From 038cbfe889138a36d8adf91d12a76ba035e78e11 Mon Sep 17 00:00:00 2001 From: Qian Yingjin Date: Wed, 8 Feb 2023 10:24:00 +0800 Subject: [PATCH 01/80] mm/filemap: fix page end in filemap_get_read_batch I was running traces of the read code against an RAID storage system to understand why read requests were being misaligned against the underlying RAID strips. I found that the page end offset calculation in filemap_get_read_batch() was off by one. When a read is submitted with end offset 1048575, then it calculates the end page for read of 256 when it should be 255. "last_index" is the index of the page beyond the end of the read and it should be skipped when get a batch of pages for read in @filemap_get_read_batch(). The below simple patch fixes the problem. This code was introduced in kernel 5.12. Link: https://lkml.kernel.org/r/20230208022400.28962-1-coolqyj@163.com Fixes: cbd59c48ae2b ("mm/filemap: use head pages in generic_file_buffered_read") Signed-off-by: Qian Yingjin Reviewed-by: Matthew Wilcox (Oracle) Cc: Signed-off-by: Andrew Morton --- mm/filemap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index c4d4ace9cc700..0e20a8d6dd93f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2588,18 +2588,19 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, struct folio *folio; int err = 0; + /* "last_index" is the index of the page beyond the end of the read */ last_index = DIV_ROUND_UP(iocb->ki_pos + iter->count, PAGE_SIZE); retry: if (fatal_signal_pending(current)) return -EINTR; - filemap_get_read_batch(mapping, index, last_index, fbatch); + filemap_get_read_batch(mapping, index, last_index - 1, fbatch); if (!folio_batch_count(fbatch)) { if (iocb->ki_flags & IOCB_NOIO) return -EAGAIN; page_cache_sync_readahead(mapping, ra, filp, index, last_index - index); - filemap_get_read_batch(mapping, index, last_index, fbatch); + filemap_get_read_batch(mapping, index, last_index - 1, fbatch); } if (!folio_batch_count(fbatch)) { if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ)) From 1e1db79e1ed6e28dd4c2380d65c7dfbb2c0b07ce Mon Sep 17 00:00:00 2001 From: Zach O'Keefe Date: Tue, 24 Jan 2023 17:57:37 -0800 Subject: [PATCH 02/80] mm/MADV_COLLAPSE: set EAGAIN on unexpected page refcount During collapse, in a few places we check to see if a given small page has any unaccounted references. If the refcount on the page doesn't match our expectations, it must be there is an unknown user concurrently interested in the page, and so it's not safe to move the contents elsewhere. However, the unaccounted pins are likely an ephemeral state. In this situation, MADV_COLLAPSE returns -EINVAL when it should return -EAGAIN. This could cause userspace to conclude that the syscall failed, when it in fact could succeed by retrying. Link: https://lkml.kernel.org/r/20230125015738.912924-1-zokeefe@google.com Fixes: 7d8faaf15545 ("mm/madvise: introduce MADV_COLLAPSE sync hugepage collapse") Signed-off-by: Zach O'Keefe Reported-by: Hugh Dickins Acked-by: Hugh Dickins Reviewed-by: Yang Shi Cc: Signed-off-by: Andrew Morton --- mm/khugepaged.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 90acfea40c13c..a26a28e3738c1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2611,6 +2611,7 @@ static int madvise_collapse_errno(enum scan_result r) case SCAN_CGROUP_CHARGE_FAIL: return -EBUSY; /* Resource temporary unavailable - trying again might succeed */ + case SCAN_PAGE_COUNT: case SCAN_PAGE_LOCK: case SCAN_PAGE_LRU: case SCAN_DEL_PAGE_LRU: From e634c0fcfe6b6e435e767a9a1849bc124e426e2a Mon Sep 17 00:00:00 2001 From: Randy Dunlap Date: Tue, 14 Feb 2023 09:02:08 -0800 Subject: [PATCH 03/80] MAINTAINERS: update FPU EMULATOR web page The web page entry for the FPU EMULATOR no longer works. I notified Bill of this and he asked me to update it to this new entry. Link: https://lkml.kernel.org/r/20230214170208.17287-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Acked-by: Bill Metzenthen Signed-off-by: Andrew Morton --- MAINTAINERS | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/MAINTAINERS b/MAINTAINERS index 123216b76534f..f4267d19749ae 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -8196,7 +8196,7 @@ F: drivers/fpga/microchip-spi.c FPU EMULATOR M: Bill Metzenthen S: Maintained -W: http://floatingpoint.sourceforge.net/emulator/index.html +W: https://floatingpoint.billm.au/ F: arch/x86/math-emu/ FRAMEBUFFER CORE From 3c0c7e6ad75a7171bb1ff1b3a1b8bc044144828d Mon Sep 17 00:00:00 2001 From: David Chen Date: Thu, 9 Feb 2023 17:48:28 +0000 Subject: [PATCH 04/80] mm/page_alloc.c: fix page corruption caused by racy check in __free_pages When we upgraded our kernel, we started seeing some page corruption like the following consistently: BUG: Bad page state in process ganesha.nfsd pfn:1304ca page:0000000022261c55 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1304ca flags: 0x17ffffc0000000() raw: 0017ffffc0000000 ffff8a513ffd4c98 ffffeee24b35ec08 0000000000000000 raw: 0000000000000000 0000000000000001 00000000ffffff7f 0000000000000000 page dumped because: nonzero mapcount CPU: 0 PID: 15567 Comm: ganesha.nfsd Kdump: loaded Tainted: P B O 5.10.158-1.nutanix.20221209.el7.x86_64 #1 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016 Call Trace: dump_stack+0x74/0x96 bad_page.cold+0x63/0x94 check_new_page_bad+0x6d/0x80 rmqueue+0x46e/0x970 get_page_from_freelist+0xcb/0x3f0 ? _cond_resched+0x19/0x40 __alloc_pages_nodemask+0x164/0x300 alloc_pages_current+0x87/0xf0 skb_page_frag_refill+0x84/0x110 ... Sometimes, it would also show up as corruption in the free list pointer and cause crashes. After bisecting the issue, we found the issue started from e320d3012d25: if (put_page_testzero(page)) free_the_page(page, order); else if (!PageHead(page)) while (order-- > 0) free_the_page(page + (1 << order), order); So the problem is the check PageHead is racy because at this point we already dropped our reference to the page. So even if we came in with compound page, the page can already be freed and PageHead can return false and we will end up freeing all the tail pages causing double free. Link: https://lkml.kernel.org/r/Message-ID: Fixes: e320d3012d25 ("mm/page_alloc.c: fix freeing non-compound pages") Signed-off-by: Chunwei Chen Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Vlastimil Babka Cc: Signed-off-by: Andrew Morton --- mm/page_alloc.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0745aedebb371..3bb3484563eda 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -5631,9 +5631,12 @@ EXPORT_SYMBOL(get_zeroed_page); */ void __free_pages(struct page *page, unsigned int order) { + /* get PageHead before we drop reference */ + int head = PageHead(page); + if (put_page_testzero(page)) free_the_page(page, order); - else if (!PageHead(page)) + else if (!head) while (order-- > 0) free_the_page(page + (1 << order), order); } From 1401fe07078636475e59b642afd1e217fff560c0 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Thu, 16 Feb 2023 10:30:59 -0500 Subject: [PATCH 05/80] mm/migrate: fix wrongly apply write bit after mkdirty on sparc64 Nick Bowler reported another sparc64 breakage after the young/dirty persistent work for page migration (per "Link:" below). That's after a similar report [2]. It turns out page migration was overlooked, and it wasn't failing before because page migration was not enabled in the initial report test environment. David proposed another way [2] to fix this from sparc64 side, but that patch didn't land somehow. Neither did I check whether there's any other arch that has similar issues. Let's fix it for now as simple as moving the write bit handling to be after dirty, like what we did before. Note: this is based on mm-unstable, because the breakage was since 6.1 and we're at a very late stage of 6.2 (-rc8), so I assume for this specific case we should target this at 6.3. [1] https://lore.kernel.org/all/20221021160603.GA23307@u164.east.ru/ [2] https://lore.kernel.org/all/20221212130213.136267-1-david@redhat.com/ Link: https://lkml.kernel.org/r/20230216153059.256739-1-peterx@redhat.com Fixes: 2e3468778dbe ("mm: remember young/dirty bit for page migrations") Link: https://lore.kernel.org/all/CADyTPExpEqaJiMGoV+Z6xVgL50ZoMJg49B10LcZ=8eg19u34BA@mail.gmail.com/ Signed-off-by: Peter Xu Reported-by: Nick Bowler Acked-by: David Hildenbrand Tested-by: Nick Bowler Cc: Cc: Signed-off-by: Andrew Morton --- mm/huge_memory.c | 6 ++++-- mm/migrate.c | 2 ++ 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index abe6cfd92ffa0..1b791b26d72d7 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3272,8 +3272,6 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot)); if (pmd_swp_soft_dirty(*pvmw->pmd)) pmde = pmd_mksoft_dirty(pmde); - if (is_writable_migration_entry(entry)) - pmde = maybe_pmd_mkwrite(pmde, vma); if (pmd_swp_uffd_wp(*pvmw->pmd)) pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); if (!is_migration_entry_young(entry)) @@ -3281,6 +3279,10 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) /* NOTE: this may contain setting soft-dirty on some archs */ if (PageDirty(new) && is_migration_entry_dirty(entry)) pmde = pmd_mkdirty(pmde); + if (is_writable_migration_entry(entry)) + pmde = maybe_pmd_mkwrite(pmde, vma); + else + pmde = pmd_wrprotect(pmde); if (PageAnon(new)) { rmap_t rmap_flags = RMAP_COMPOUND; diff --git a/mm/migrate.c b/mm/migrate.c index a4d3fc65085f3..cc5455614e018 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -224,6 +224,8 @@ static bool remove_migration_pte(struct folio *folio, pte = maybe_mkwrite(pte, vma); else if (pte_swp_uffd_wp(*pvmw.pte)) pte = pte_mkuffd_wp(pte); + else + pte = pte_wrprotect(pte); if (folio_test_anon(folio) && !is_readable_migration_entry(entry)) rmap_flags |= RMAP_EXCLUSIVE; From 7f2907571c2dca296c693a50e4554a704a7e54df Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Wed, 15 Feb 2023 17:35:42 -0800 Subject: [PATCH 06/80] hugetlb: check for undefined shift on 32 bit architectures Users can specify the hugetlb page size in the mmap, shmget and memfd_create system calls. This is done by using 6 bits within the flags argument to encode the base-2 logarithm of the desired page size. The routine hstate_sizelog() uses the log2 value to find the corresponding hugetlb hstate structure. Converting the log2 value (page_size_log) to potential hugetlb page size is the simple statement: 1UL << page_size_log Because only 6 bits are used for page_size_log, the left shift can not be greater than 63. This is fine on 64 bit architectures where a long is 64 bits. However, if a value greater than 31 is passed on a 32 bit architecture (where long is 32 bits) the shift will result in undefined behavior. This was generally not an issue as the result of the undefined shift had to exactly match hugetlb page size to proceed. Recent improvements in runtime checking have resulted in this undefined behavior throwing errors such as reported below. Fix by comparing page_size_log to BITS_PER_LONG before doing shift. Link: https://lkml.kernel.org/r/20230216013542.138708-1-mike.kravetz@oracle.com Link: https://lore.kernel.org/lkml/CA+G9fYuei_Tr-vN9GS7SfFyU1y9hNysnf=PB7kT0=yv4MiPgVg@mail.gmail.com/ Fixes: 42d7395feb56 ("mm: support more pagesizes for MAP_HUGETLB/SHM_HUGETLB") Signed-off-by: Mike Kravetz Reported-by: Naresh Kamboju Reviewed-by: Jesper Juhl Acked-by: Muchun Song Tested-by: Linux Kernel Functional Testing Tested-by: Naresh Kamboju Cc: Anders Roxell Cc: Andi Kleen Cc: Sasha Levin Cc: Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index db194e2ba69fd..9ab9d3105d5c2 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -743,7 +743,10 @@ static inline struct hstate *hstate_sizelog(int page_size_log) if (!page_size_log) return &default_hstate; - return size_to_hstate(1UL << page_size_log); + if (page_size_log < BITS_PER_LONG) + return size_to_hstate(1UL << page_size_log); + + return NULL; } static inline struct hstate *hstate_vma(struct vm_area_struct *vma) From f9cd4a95ea6db3735223f70c6aff8ca6627e782f Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Wed, 15 Feb 2023 07:40:43 +0900 Subject: [PATCH 07/80] nilfs2: fix underflow in second superblock position calculations Macro NILFS_SB2_OFFSET_BYTES, which computes the position of the second superblock, underflows when the argument device size is less than 4096 bytes. Therefore, when using this macro, it is necessary to check in advance that the device size is not less than a lower limit, or at least that underflow does not occur. The current nilfs2 implementation lacks this check, causing out-of-bound block access when mounting devices smaller than 4096 bytes: I/O error, dev loop0, sector 36028797018963960 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 2 NILFS (loop0): unable to read secondary superblock (blocksize = 1024) In addition, when trying to resize the filesystem to a size below 4096 bytes, this underflow occurs in nilfs_resize_fs(), passing a huge number of segments to nilfs_sufile_resize(), corrupting parameters such as the number of segments in superblocks. This causes excessive loop iterations in nilfs_sufile_resize() during a subsequent resize ioctl, causing semaphore ns_segctor_sem to block for a long time and hang the writer thread: INFO: task segctord:5067 blocked for more than 143 seconds. Not tainted 6.2.0-rc8-syzkaller-00015-gf6feea56f66d #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:segctord state:D stack:23456 pid:5067 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5293 [inline] __schedule+0x1409/0x43f0 kernel/sched/core.c:6606 schedule+0xc3/0x190 kernel/sched/core.c:6682 rwsem_down_write_slowpath+0xfcf/0x14a0 kernel/locking/rwsem.c:1190 nilfs_transaction_lock+0x25c/0x4f0 fs/nilfs2/segment.c:357 nilfs_segctor_thread_construct fs/nilfs2/segment.c:2486 [inline] nilfs_segctor_thread+0x52f/0x1140 fs/nilfs2/segment.c:2570 kthread+0x270/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 ... Call Trace: folio_mark_accessed+0x51c/0xf00 mm/swap.c:515 __nilfs_get_page_block fs/nilfs2/page.c:42 [inline] nilfs_grab_buffer+0x3d3/0x540 fs/nilfs2/page.c:61 nilfs_mdt_submit_block+0xd7/0x8f0 fs/nilfs2/mdt.c:121 nilfs_mdt_read_block+0xeb/0x430 fs/nilfs2/mdt.c:176 nilfs_mdt_get_block+0x12d/0xbb0 fs/nilfs2/mdt.c:251 nilfs_sufile_get_segment_usage_block fs/nilfs2/sufile.c:92 [inline] nilfs_sufile_truncate_range fs/nilfs2/sufile.c:679 [inline] nilfs_sufile_resize+0x7a3/0x12b0 fs/nilfs2/sufile.c:777 nilfs_resize_fs+0x20c/0xed0 fs/nilfs2/super.c:422 nilfs_ioctl_resize fs/nilfs2/ioctl.c:1033 [inline] nilfs_ioctl+0x137c/0x2440 fs/nilfs2/ioctl.c:1301 ... This fixes these issues by inserting appropriate minimum device size checks or anti-underflow checks, depending on where the macro is used. Link: https://lkml.kernel.org/r/0000000000004e1dfa05f4a48e6b@google.com Link: https://lkml.kernel.org/r/20230214224043.24141-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi Reported-by: Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton --- fs/nilfs2/ioctl.c | 7 +++++++ fs/nilfs2/super.c | 9 +++++++++ fs/nilfs2/the_nilfs.c | 8 +++++++- 3 files changed, 23 insertions(+), 1 deletion(-) diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index 87e1004b606d2..b4041d0566a9a 100644 --- a/fs/nilfs2/ioctl.c +++ b/fs/nilfs2/ioctl.c @@ -1114,7 +1114,14 @@ static int nilfs_ioctl_set_alloc_range(struct inode *inode, void __user *argp) minseg = range[0] + segbytes - 1; do_div(minseg, segbytes); + + if (range[1] < 4096) + goto out; + maxseg = NILFS_SB2_OFFSET_BYTES(range[1]); + if (maxseg < segbytes) + goto out; + do_div(maxseg, segbytes); maxseg--; diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 6edb6e0dd61f7..1422b8ba24ed6 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -408,6 +408,15 @@ int nilfs_resize_fs(struct super_block *sb, __u64 newsize) if (newsize > devsize) goto out; + /* + * Prevent underflow in second superblock position calculation. + * The exact minimum size check is done in nilfs_sufile_resize(). + */ + if (newsize < 4096) { + ret = -ENOSPC; + goto out; + } + /* * Write lock is required to protect some functions depending * on the number of segments, the number of reserved segments, diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index 2064e6473d304..3a4c9c150cbf5 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -544,9 +544,15 @@ static int nilfs_load_super_block(struct the_nilfs *nilfs, { struct nilfs_super_block **sbp = nilfs->ns_sbp; struct buffer_head **sbh = nilfs->ns_sbh; - u64 sb2off = NILFS_SB2_OFFSET_BYTES(bdev_nr_bytes(nilfs->ns_bdev)); + u64 sb2off, devsize = bdev_nr_bytes(nilfs->ns_bdev); int valid[2], swp = 0; + if (devsize < NILFS_SEG_MIN_BLOCKS * NILFS_MIN_BLOCK_SIZE + 4096) { + nilfs_err(sb, "device size too small"); + return -EINVAL; + } + sb2off = NILFS_SB2_OFFSET_BYTES(devsize); + sbp[0] = nilfs_read_super_block(sb, NILFS_SB_OFFSET_BYTES, blocksize, &sbh[0]); sbp[1] = nilfs_read_super_block(sb, sb2off, blocksize, &sbh[1]); From 3f0ec7fb2b3530f69a0424d6fbf1fdc75a1ef87f Mon Sep 17 00:00:00 2001 From: Jiaqi Yan Date: Mon, 5 Dec 2022 15:40:58 -0800 Subject: [PATCH 08/80] mm/khugepaged: recover from poisoned anonymous memory MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Patch series "Memory poison recovery in khugepaged collapsing", v9. Problem ======= Memory DIMMs are subject to multi-bit flips, i.e. memory errors. As memory size and density increase, the chances of and number of memory errors increase. The increasing size and density of server RAM in the data center and cloud have shown increased uncorrectable memory errors. There are already mechanisms in the kernel to recover from uncorrectable memory errors. This series of patches provides the recovery mechanism for the particular kernel agent khugepaged when it collapses memory pages. Impact ====== The main reason we chose to make khugepaged collapsing tolerant of memory failures was its high possibility of accessing poisoned memory while performing functionally optional compaction actions. Standard applications typically don't have strict requirements on the size of their pages. So they are given 4K pages by the kernel. The kernel is able to improve application performance by either 1) giving applications 2M pages to begin with, or 2) collapsing 4K pages into 2M pages when possible. This collapsing operation is done by khugepaged, a kernel agent that is constantly scanning memory. When collapsing 4K pages into a 2M page, it must copy the data from the 4K pages into a physically contiguous 2M page. Therefore, as long as there exists one poisoned cache line in collapsible 4K pages, khugepaged will eventually access it. The current impact to users is a machine check exception triggered kernel panic. However, khugepaged’s compaction operations are not functionally required kernel actions. Therefore making khugepaged tolerant to poisoned memory will greatly improve user experience. This patch series is for cases where khugepaged is the first guy that detects the memory errors on the poisoned pages. IOW, the pages are not known to have memory errors when khugepaged collapsing gets to them. In our observation, this happens frequently when the huge page ratio of the system is relatively low, which is fairly common in virtual machines running on cloud. Solution ======== As stated before, it is less desirable to crash the system only because khugepaged accesses poisoned pages while it is collapsing 4K pages. The high level idea of this patch series is to skip the group of pages (usually 512 4K-size pages) once khugepaged finds one of them is poisoned, as these pages have become ineligible to be collapsed. We are also careful to unwind operations khuagepaged has performed before it detects memory failures. For example, before copying and collapsing a group of anonymous pages into a huge page, the source pages will be isolated and their page table is unlinked from their PMD. These operations need to be undone in order to ensure these pages are not changed/lost from the perspective of other threads (both user and kernel space). As for file backed memory pages, there already exists a rollback case. This patch just extends it so that khugepaged also correctly rolls back when it fails to copy poisoned 4K pages. This patch (of 2): Make __collapse_huge_page_copy return whether copying anonymous pages succeeded, and make collapse_huge_page handle the return status. Break existing PTE scan loop into two for-loops. The first loop copies source pages into target huge page, and can fail gracefully when running into memory errors in source pages. If copying all pages succeeds, the second loop releases and clears up these normal pages. Otherwise, the second loop rolls back the page table and page states by: - re-establishing the original PTEs-to-PMD connection. - releasing source pages back to their LRU list. Tested manually: 0. Enable khugepaged on system under test. 1. Start a two-thread application. Each thread allocates a chunk of non-huge anonymous memory buffer. 2. Pick 4 random buffer locations (2 in each thread) and inject uncorrectable memory errors at corresponding physical addresses. 3. Signal both threads to make their memory buffer collapsible, i.e. calling madvise(MADV_HUGEPAGE). 4. Wait and check kernel log: khugepaged is able to recover from poisoned pages and skips collapsing them. 5. Signal both threads to inspect their buffer contents and make sure no data corruption. Link: https://lkml.kernel.org/r/20221205234059.42971-1-jiaqiyan@google.com Link: https://lkml.kernel.org/r/20221205234059.42971-2-jiaqiyan@google.com Signed-off-by: Jiaqi Yan Cc: Kefeng Wang Cc: Kirill A. Shutemov Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Tony Luck Cc: Yang Shi Cc: Signed-off-by: Andrew Morton --- include/trace/events/huge_memory.h | 3 +- mm/khugepaged.c | 179 ++++++++++++++++++++++------- 2 files changed, 139 insertions(+), 43 deletions(-) diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h index 3e6fb05852f9a..46cce509957ba 100644 --- a/include/trace/events/huge_memory.h +++ b/include/trace/events/huge_memory.h @@ -36,7 +36,8 @@ EM( SCAN_ALLOC_HUGE_PAGE_FAIL, "alloc_huge_page_failed") \ EM( SCAN_CGROUP_CHARGE_FAIL, "ccgroup_charge_failed") \ EM( SCAN_TRUNCATED, "truncated") \ - EMe(SCAN_PAGE_HAS_PRIVATE, "page_has_private") \ + EM( SCAN_PAGE_HAS_PRIVATE, "page_has_private") \ + EMe(SCAN_COPY_MC, "copy_poisoned_page") \ #undef EM #undef EMe diff --git a/mm/khugepaged.c b/mm/khugepaged.c index acf8ea617cd32..2696de98cdd24 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include @@ -55,6 +56,7 @@ enum scan_result { SCAN_CGROUP_CHARGE_FAIL, SCAN_TRUNCATED, SCAN_PAGE_HAS_PRIVATE, + SCAN_COPY_MC, }; #define CREATE_TRACE_POINTS @@ -541,6 +543,27 @@ static bool is_refcount_suitable(struct page *page) return page_count(page) == expected_refcount; } +/* + * Copies memory with #MC in source page (@from) handled. Returns number + * of bytes not copied if there was an exception; otherwise 0 for success. + * Note handling #MC requires arch opt-in. + */ +static int copy_mc_page(struct page *to, struct page *from) +{ + char *vfrom, *vto; + unsigned long ret; + + vfrom = kmap_local_page(from); + vto = kmap_local_page(to); + ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE); + if (ret == 0) + kmsan_copy_page_meta(to, from); + kunmap_local(vto); + kunmap_local(vfrom); + + return ret; +} + static int __collapse_huge_page_isolate(struct vm_area_struct *vma, unsigned long address, pte_t *pte, @@ -681,56 +704,124 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, return result; } -static void __collapse_huge_page_copy(pte_t *pte, struct page *page, - struct vm_area_struct *vma, - unsigned long address, - spinlock_t *ptl, - struct list_head *compound_pagelist) +/* + * __collapse_huge_page_copy - attempts to copy memory contents from normal + * pages to a hugepage. Cleans up the normal pages if copying succeeds; + * otherwise restores the original page table and releases isolated normal pages. + * Returns SCAN_SUCCEED if copying succeeds, otherwise returns SCAN_COPY_MC. + * + * @pte: starting of the PTEs to copy from + * @page: the new hugepage to copy contents to + * @pmd: pointer to the new hugepage's PMD + * @rollback: the original normal pages' PMD + * @vma: the original normal pages' virtual memory area + * @address: starting address to copy + * @pte_ptl: lock on normal pages' PTEs + * @compound_pagelist: list that stores compound pages + */ +static int __collapse_huge_page_copy(pte_t *pte, + struct page *page, + pmd_t *pmd, + pmd_t rollback, + struct vm_area_struct *vma, + unsigned long address, + spinlock_t *pte_ptl, + struct list_head *compound_pagelist) { struct page *src_page, *tmp; pte_t *_pte; - for (_pte = pte; _pte < pte + HPAGE_PMD_NR; - _pte++, page++, address += PAGE_SIZE) { - pte_t pteval = *_pte; + pte_t pteval; + unsigned long _address; + spinlock_t *pmd_ptl; + int result = SCAN_SUCCEED; - if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { - clear_user_highpage(page, address); - add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); - if (is_zero_pfn(pte_pfn(pteval))) { + /* + * Copying pages' contents is subject to memory poison at any iteration. + */ + for (_pte = pte, _address = address; _pte < pte + HPAGE_PMD_NR; + _pte++, page++, _address += PAGE_SIZE) { + pteval = *_pte; + + if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) + clear_user_highpage(page, _address); + else { + src_page = pte_page(pteval); + if (copy_mc_page(page, src_page) > 0) { + result = SCAN_COPY_MC; + break; + } + } + } + + if (likely(result == SCAN_SUCCEED)) { + for (_pte = pte, _address = address; _pte < pte + HPAGE_PMD_NR; + _pte++, _address += PAGE_SIZE) { + pteval = *_pte; + if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) { + add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1); + if (is_zero_pfn(pte_pfn(pteval))) { + /* + * pte_ptl mostly unnecessary. + */ + spin_lock(pte_ptl); + pte_clear(vma->vm_mm, _address, _pte); + spin_unlock(pte_ptl); + } + } else { + src_page = pte_page(pteval); + if (!PageCompound(src_page)) + release_pte_page(src_page); /* - * ptl mostly unnecessary. + * pte_ptl mostly unnecessary, but preempt has + * to be disabled to update the per-cpu stats + * inside page_remove_rmap(). */ - spin_lock(ptl); - ptep_clear(vma->vm_mm, address, _pte); - spin_unlock(ptl); + spin_lock(pte_ptl); + ptep_clear(vma->vm_mm, _address, _pte); + page_remove_rmap(src_page, vma, false); + spin_unlock(pte_ptl); + free_page_and_swap_cache(src_page); + } + } + list_for_each_entry_safe(src_page, tmp, compound_pagelist, lru) { + list_del(&src_page->lru); + mod_node_page_state(page_pgdat(src_page), + NR_ISOLATED_ANON + page_is_file_lru(src_page), + -compound_nr(src_page)); + unlock_page(src_page); + free_swap_cache(src_page); + putback_lru_page(src_page); + } + } else { + /* + * Re-establish the regular PMD that points to the regular + * page table. Restoring PMD needs to be done prior to + * releasing pages. Since pages are still isolated and + * locked here, acquiring anon_vma_lock_write is unnecessary. + */ + pmd_ptl = pmd_lock(vma->vm_mm, pmd); + pmd_populate(vma->vm_mm, pmd, pmd_pgtable(rollback)); + spin_unlock(pmd_ptl); + /* + * Release both raw and compound pages isolated + * in __collapse_huge_page_isolate. + */ + for (_pte = pte, _address = address; _pte < pte + HPAGE_PMD_NR; + _pte++, _address += PAGE_SIZE) { + pteval = *_pte; + if (!pte_none(pteval) && !is_zero_pfn(pte_pfn(pteval))) { + src_page = pte_page(pteval); + if (!PageCompound(src_page)) + release_pte_page(src_page); } - } else { - src_page = pte_page(pteval); - copy_user_highpage(page, src_page, address, vma); - if (!PageCompound(src_page)) - release_pte_page(src_page); - /* - * ptl mostly unnecessary, but preempt has to - * be disabled to update the per-cpu stats - * inside page_remove_rmap(). - */ - spin_lock(ptl); - ptep_clear(vma->vm_mm, address, _pte); - page_remove_rmap(src_page, vma, false); - spin_unlock(ptl); - free_page_and_swap_cache(src_page); + } + list_for_each_entry_safe(src_page, tmp, compound_pagelist, lru) { + list_del(&src_page->lru); + release_pte_page(src_page); } } - list_for_each_entry_safe(src_page, tmp, compound_pagelist, lru) { - list_del(&src_page->lru); - mod_node_page_state(page_pgdat(src_page), - NR_ISOLATED_ANON + page_is_file_lru(src_page), - -compound_nr(src_page)); - unlock_page(src_page); - free_swap_cache(src_page); - putback_lru_page(src_page); - } + return result; } static void khugepaged_alloc_sleep(void) @@ -1098,9 +1189,13 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, */ anon_vma_unlock_write(vma->anon_vma); - __collapse_huge_page_copy(pte, hpage, vma, address, pte_ptl, - &compound_pagelist); + result = __collapse_huge_page_copy(pte, hpage, pmd, _pmd, + vma, address, pte_ptl, + &compound_pagelist); pte_unmap(pte); + if (unlikely(result != SCAN_SUCCEED)) + goto out_up_write; + /* * spin_lock() below is not the equivalent of smp_wmb(), but * the smp_wmb() inside __SetPageUptodate() can be reused to From 4edc9840addba3ad4d7d53444d27f4a165916d12 Mon Sep 17 00:00:00 2001 From: Jiaqi Yan Date: Mon, 5 Dec 2022 15:40:59 -0800 Subject: [PATCH 09/80] mm/khugepaged: recover from poisoned file-backed memory Make collapse_file roll back when copying pages failed. More concretely: - extract copying operations into a separate loop - postpone the updates for nr_none until both scanning and copying succeeded - postpone joining small xarray entries until both scanning and copying succeeded - postpone the update operations to NR_XXX_THPS until both scanning and copying succeeded - for non-SHMEM file, roll back filemap_nr_thps_inc if scan succeeded but copying failed Tested manually: 0. Enable khugepaged on system under test. Mount tmpfs at /mnt/ramdisk. 1. Start a two-thread application. Each thread allocates a chunk of non-huge memory buffer from /mnt/ramdisk. 2. Pick 4 random buffer address (2 in each thread) and inject uncorrectable memory errors at physical addresses. 3. Signal both threads to make their memory buffer collapsible, i.e. calling madvise(MADV_HUGEPAGE). 4. Wait and then check kernel log: khugepaged is able to recover from poisoned pages by skipping them. 5. Signal both threads to inspect their buffer contents and make sure no data corruption. Link: https://lkml.kernel.org/r/20221205234059.42971-3-jiaqiyan@google.com Signed-off-by: Jiaqi Yan Acked-by: Kirill A. Shutemov Cc: Kefeng Wang Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Cc: Tony Luck Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/khugepaged.c | 78 ++++++++++++++++++++++++++++++------------------- 1 file changed, 48 insertions(+), 30 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 2696de98cdd24..a5d32231bfad9 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1868,6 +1868,9 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, { struct address_space *mapping = file->f_mapping; struct page *hpage; + struct page *page; + struct page *tmp; + struct folio *folio; pgoff_t index = 0, end = start + HPAGE_PMD_NR; LIST_HEAD(pagelist); XA_STATE_ORDER(xas, &mapping->i_pages, start, HPAGE_PMD_ORDER); @@ -1912,8 +1915,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, xas_set(&xas, start); for (index = start; index < end; index++) { - struct page *page = xas_next(&xas); - struct folio *folio; + page = xas_next(&xas); VM_BUG_ON(index != xas.xa_index); if (is_shmem) { @@ -2095,10 +2097,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, } nr = thp_nr_pages(hpage); - if (is_shmem) - __mod_lruvec_page_state(hpage, NR_SHMEM_THPS, nr); - else { - __mod_lruvec_page_state(hpage, NR_FILE_THPS, nr); + if (!is_shmem) { filemap_nr_thps_inc(mapping); /* * Paired with smp_mb() in do_dentry_open() to ensure @@ -2109,21 +2108,10 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, smp_mb(); if (inode_is_open_for_write(mapping->host)) { result = SCAN_FAIL; - __mod_lruvec_page_state(hpage, NR_FILE_THPS, -nr); filemap_nr_thps_dec(mapping); goto xa_locked; } } - - if (nr_none) { - __mod_lruvec_page_state(hpage, NR_FILE_PAGES, nr_none); - /* nr_none is always 0 for non-shmem. */ - __mod_lruvec_page_state(hpage, NR_SHMEM, nr_none); - } - - /* Join all the small entries into a single multi-index entry */ - xas_set_order(&xas, start, HPAGE_PMD_ORDER); - xas_store(&xas, hpage); xa_locked: xas_unlock_irq(&xas); xa_unlocked: @@ -2136,21 +2124,35 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, try_to_unmap_flush(); if (result == SCAN_SUCCEED) { - struct page *page, *tmp; - struct folio *folio; - /* * Replacing old pages with new one has succeeded, now we - * need to copy the content and free the old pages. + * attempt to copy the contents. */ index = start; - list_for_each_entry_safe(page, tmp, &pagelist, lru) { + list_for_each_entry(page, &pagelist, lru) { while (index < page->index) { clear_highpage(hpage + (index % HPAGE_PMD_NR)); index++; } - copy_highpage(hpage + (page->index % HPAGE_PMD_NR), - page); + if (copy_mc_page(hpage + (page->index % HPAGE_PMD_NR), + page) > 0) { + result = SCAN_COPY_MC; + break; + } + index++; + } + while (result == SCAN_SUCCEED && index < end) { + clear_highpage(hpage + (index % HPAGE_PMD_NR)); + index++; + } + } + + if (result == SCAN_SUCCEED) { + /* + * Copying old pages to huge one has succeeded, now we + * need to free the old pages. + */ + list_for_each_entry_safe(page, tmp, &pagelist, lru) { list_del(&page->lru); page->mapping = NULL; page_ref_unfreeze(page, 1); @@ -2158,12 +2160,23 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, ClearPageUnevictable(page); unlock_page(page); put_page(page); - index++; } - while (index < end) { - clear_highpage(hpage + (index % HPAGE_PMD_NR)); - index++; + + xas_lock_irq(&xas); + if (is_shmem) + __mod_lruvec_page_state(hpage, NR_SHMEM_THPS, nr); + else + __mod_lruvec_page_state(hpage, NR_FILE_THPS, nr); + + if (nr_none) { + __mod_lruvec_page_state(hpage, NR_FILE_PAGES, nr_none); + /* nr_none is always 0 for non-shmem. */ + __mod_lruvec_page_state(hpage, NR_SHMEM, nr_none); } + /* Join all the small entries into a single multi-index entry. */ + xas_set_order(&xas, start, HPAGE_PMD_ORDER); + xas_store(&xas, hpage); + xas_unlock_irq(&xas); folio = page_folio(hpage); folio_mark_uptodate(folio); @@ -2181,8 +2194,6 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, unlock_page(hpage); hpage = NULL; } else { - struct page *page; - /* Something went wrong: roll back page cache changes */ xas_lock_irq(&xas); if (nr_none) { @@ -2216,6 +2227,13 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, xas_lock_irq(&xas); } VM_BUG_ON(nr_none); + /* + * Undo the updates of filemap_nr_thps_inc for non-SHMEM file only. + * This undo is not needed unless failure is due to SCAN_COPY_MC. + */ + if (!is_shmem && result == SCAN_COPY_MC) + filemap_nr_thps_dec(mapping); + xas_unlock_irq(&xas); hpage->mapping = NULL; From 9be80625eeaa3f578d11b5e49f3d9d2eed70e74d Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 30 Dec 2022 09:12:44 +0800 Subject: [PATCH 10/80] ksm: abstract the function try_to_get_old_rmap_item Patch series "ksm: support tracking KSM-placed zero-pages", v6. The core idea of this patch set is to enable users to perceive the number of any pages merged by KSM, regardless of whether use_zero_page switch has been turned on, so that users can know how much free memory increase is really due to their madvise(MERGEABLE) actions. But the problem is, when enabling use_zero_pages, all empty pages will be merged with kernel zero pages instead of with each other as use_zero_pages is disabled, and then these zero-pages are no longer monitored by KSM. The motivations for me to do this contains three points: 1) MADV_UNMERGEABLE and other ways to trigger unsharing will *not* unshare the shared zeropage as placed by KSM (which is against the MADV_UNMERGEABLE documentation at least); see the link: https://lore.kernel.org/lkml/4a3daba6-18f9-d252-697c-197f65578c44@redhat.com/ 2) We cannot know how many pages are zero pages placed by KSM when enabling use_zero_pages, which hides the critical information about how much actual memory are really saved by KSM. Knowing how many ksm-placed zero pages are helpful for user to use the policy of madvise (MERGEABLE) better because they can see the actual profit brought by KSM. 3) The zero pages placed-by KSM are different from those initial empty page (filled with zeros) which are never touched by applications. The former is active-merged by KSM while the later have never consume actual memory. use_zero_pages is useful, not only because of cache colouring as described in doc, but also because use_zero_pages can accelerate merging empty pages when there are plenty of empty pages (full of zeros) as the time of page-by-page comparisons (unstable_tree_search_insert) is saved. So we hope to implement the support for ksm zero page tracking without affecting the feature of use_zero_pages. Zero pages may be the most common merged pages in actual environment(not only VM but also including other application like containers). Enabling use_zero_pages in the environment with plenty of empty pages(full of zeros) will be very useful. Users and app developer can also benefit from knowing the proportion of zero pages in all merged pages to optimize applications. With the patch series, we can both unshare zero-pages(KSM-placed) accurately and count ksm zero pages with enabling use_zero_pages. This patch (of 6): A new function try_to_get_old_rmap_item is abstracted from get_next_rmap_item. This function will be reused by the subsequent patches about counting ksm_zero_pages. The patch improves the readability and reusability of KSM code. Link: https://lkml.kernel.org/r/202302100915227721315@zte.com.cn Link: https://lkml.kernel.org/r/202212300911327101708@zte.com.cn Link: https://lkml.kernel.org/r/202212300912449061763@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: David Hildenbrand Cc: Claudio Imbrenda Cc: Xuexin Jiang Signed-off-by: Andrew Morton --- mm/ksm.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index ad591b779d534..79ffadd18f8af 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2213,23 +2213,36 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite } } -static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, - struct ksm_rmap_item **rmap_list, - unsigned long addr) +static struct ksm_rmap_item *try_to_get_old_rmap_item(unsigned long addr, + struct ksm_rmap_item **rmap_list) { - struct ksm_rmap_item *rmap_item; - while (*rmap_list) { - rmap_item = *rmap_list; + struct ksm_rmap_item *rmap_item = *rmap_list; if ((rmap_item->address & PAGE_MASK) == addr) return rmap_item; if (rmap_item->address > addr) break; *rmap_list = rmap_item->rmap_list; + /* Running here indicates it's vma has been UNMERGEABLE */ remove_rmap_item_from_tree(rmap_item); free_rmap_item(rmap_item); } + return NULL; +} + +static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, + struct ksm_rmap_item **rmap_list, + unsigned long addr) +{ + struct ksm_rmap_item *rmap_item; + + /* lookup if we have a old rmap_item matching the addr*/ + rmap_item = try_to_get_old_rmap_item(addr, rmap_list); + if (rmap_item) + return rmap_item; + + /* Need to allocate a new rmap_item */ rmap_item = alloc_rmap_item(); if (rmap_item) { /* It has already been zeroed */ From 521a51cc471be624f61d2651ea6ab361e1d67fc1 Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 10 Feb 2023 09:16:42 +0800 Subject: [PATCH 11/80] ksm-abstract-the-function-try_to_get_old_rmap_item-v6 modify some comments according to David's suggestions. Link: https://lkml.kernel.org/r/202302100916423431376@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: David Hildenbrand Cc: Claudio Imbrenda Cc: Xuexin Jiang Signed-off-by: Andrew Morton --- mm/ksm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 79ffadd18f8af..39a71bd25e4c4 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -2218,12 +2218,16 @@ static struct ksm_rmap_item *try_to_get_old_rmap_item(unsigned long addr, { while (*rmap_list) { struct ksm_rmap_item *rmap_item = *rmap_list; + if ((rmap_item->address & PAGE_MASK) == addr) return rmap_item; if (rmap_item->address > addr) break; *rmap_list = rmap_item->rmap_list; - /* Running here indicates it's vma has been UNMERGEABLE */ + /* + * If we end up here, the VMA is MADV_UNMERGEABLE or its page + * is ineligible or discarded, e.g. MADV_DONTNEED. + */ remove_rmap_item_from_tree(rmap_item); free_rmap_item(rmap_item); } @@ -2237,12 +2241,10 @@ static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, { struct ksm_rmap_item *rmap_item; - /* lookup if we have a old rmap_item matching the addr*/ rmap_item = try_to_get_old_rmap_item(addr, rmap_list); if (rmap_item) return rmap_item; - /* Need to allocate a new rmap_item */ rmap_item = alloc_rmap_item(); if (rmap_item) { /* It has already been zeroed */ From 409aabda934c196164ec42fb174078e842c659b9 Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 30 Dec 2022 09:13:57 +0800 Subject: [PATCH 12/80] ksm: support unsharing zero pages placed by KSM use_zero_pages may be very useful, not just because of cache colouring as described in doc, but also because use_zero_pages can accelerate merging empty pages when there are plenty of empty pages (full of zeros) as the time of page-by-page comparisons (unstable_tree_search_insert) is saved. But when enabling use_zero_pages, madvise(addr, len, MADV_UNMERGEABLE) and other ways (like write 2 to /sys/kernel/mm/ksm/run) to trigger unsharing will *not* actually unshare the shared zeropage as placed by KSM (which is against the MADV_UNMERGEABLE documentation). As these KSM-placed zero pages are out of the control of KSM, the related counts of ksm pages don't expose how many zero pages are placed by KSM (these special zero pages are different from those initially mapped zero pages, because the zero pages mapped to MADV_UNMERGEABLE areas are expected to be a complete and unshared page) To not blindly unshare all shared zero_pages in applicable VMAs, the patch introduces a dedicated flag ZERO_PAGE_FLAG to mark the rmap_items of those shared zero_pages. and guarantee that these rmap_items will be not freed during the time of zero_pages not being writing, so we can only unshare the *KSM-placed* zero_pages. The patch will not degrade the performance of use_zero_pages as it doesn't change the way of merging empty pages in use_zero_pages's feature. Link: https://lkml.kernel.org/r/202212300913573751808@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Reported-by: David Hildenbrand Cc: Claudio Imbrenda Cc: Xuexin Jiang Signed-off-by: Andrew Morton --- mm/ksm.c | 141 +++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 111 insertions(+), 30 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 39a71bd25e4c4..2897c34176993 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -214,6 +214,7 @@ struct ksm_rmap_item { #define SEQNR_MASK 0x0ff /* low bits of unstable tree seqnr */ #define UNSTABLE_FLAG 0x100 /* is a node of the unstable tree */ #define STABLE_FLAG 0x200 /* is listed from the stable tree */ +#define ZERO_PAGE_FLAG 0x400 /* is zero page placed by KSM */ /* The stable and unstable tree heads */ static struct rb_root one_stable_tree[1] = { RB_ROOT }; @@ -420,6 +421,11 @@ static inline bool ksm_test_exit(struct mm_struct *mm) return atomic_read(&mm->mm_users) == 0; } +enum break_ksm_pmd_entry_return_flag { + HAVE_KSM_PAGE = 1, + HAVE_ZERO_PAGE +}; + static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long next, struct mm_walk *walk) { @@ -427,6 +433,7 @@ static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long nex spinlock_t *ptl; pte_t *pte; int ret; + bool is_zero_page = false; if (pmd_leaf(*pmd) || !pmd_present(*pmd)) return 0; @@ -434,6 +441,8 @@ static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long nex pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); if (pte_present(*pte)) { page = vm_normal_page(walk->vma, addr, *pte); + if (!page) + is_zero_page = is_zero_pfn(pte_pfn(*pte)); } else if (!pte_none(*pte)) { swp_entry_t entry = pte_to_swp_entry(*pte); @@ -444,7 +453,14 @@ static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long nex if (is_migration_entry(entry)) page = pfn_swap_entry_to_page(entry); } - ret = page && PageKsm(page); + + if (page && PageKsm(page)) + ret = HAVE_KSM_PAGE; + else if (is_zero_page) + ret = HAVE_ZERO_PAGE; + else + ret = 0; + pte_unmap_unlock(pte, ptl); return ret; } @@ -466,19 +482,22 @@ static const struct mm_walk_ops break_ksm_ops = { * of the process that owns 'vma'. We also do not want to enforce * protection keys here anyway. */ -static int break_ksm(struct vm_area_struct *vma, unsigned long addr) +static int break_ksm(struct vm_area_struct *vma, unsigned long addr, + bool unshare_zero_page) { vm_fault_t ret = 0; do { - int ksm_page; + int walk_result; cond_resched(); - ksm_page = walk_page_range_vma(vma, addr, addr + 1, + walk_result = walk_page_range_vma(vma, addr, addr + 1, &break_ksm_ops, NULL); - if (WARN_ON_ONCE(ksm_page < 0)) - return ksm_page; - if (!ksm_page) + if (WARN_ON_ONCE(walk_result < 0)) + return walk_result; + if (!walk_result) + return 0; + if (walk_result == HAVE_ZERO_PAGE && !unshare_zero_page) return 0; ret = handle_mm_fault(vma, addr, FAULT_FLAG_UNSHARE | FAULT_FLAG_REMOTE, @@ -539,7 +558,7 @@ static void break_cow(struct ksm_rmap_item *rmap_item) mmap_read_lock(mm); vma = find_mergeable_vma(mm, addr); if (vma) - break_ksm(vma, addr); + break_ksm(vma, addr, false); mmap_read_unlock(mm); } @@ -764,6 +783,30 @@ static struct page *get_ksm_page(struct ksm_stable_node *stable_node, return NULL; } +/* + * Cleaning the rmap_item's ZERO_PAGE_FLAG + * This function will be called when unshare or writing on zero pages. + */ +static inline void clean_rmap_item_zero_flag(struct ksm_rmap_item *rmap_item) +{ + if (rmap_item->address & ZERO_PAGE_FLAG) + rmap_item->address &= PAGE_MASK; +} + +/* Only called when rmap_item is going to be freed */ +static inline void unshare_zero_pages(struct ksm_rmap_item *rmap_item) +{ + struct vm_area_struct *vma; + + if (rmap_item->address & ZERO_PAGE_FLAG) { + vma = vma_lookup(rmap_item->mm, rmap_item->address); + if (vma && !ksm_test_exit(rmap_item->mm)) + break_ksm(vma, rmap_item->address, true); + } + /* Put at last. */ + clean_rmap_item_zero_flag(rmap_item); +} + /* * Removing rmap_item from stable or unstable tree. * This function will clean the information from the stable/unstable tree. @@ -824,6 +867,7 @@ static void remove_trailing_rmap_items(struct ksm_rmap_item **rmap_list) struct ksm_rmap_item *rmap_item = *rmap_list; *rmap_list = rmap_item->rmap_list; remove_rmap_item_from_tree(rmap_item); + unshare_zero_pages(rmap_item); free_rmap_item(rmap_item); } } @@ -853,7 +897,7 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma, if (signal_pending(current)) err = -ERESTARTSYS; else - err = break_ksm(vma, addr); + err = break_ksm(vma, addr, false); } return err; } @@ -2043,6 +2087,39 @@ static void stable_tree_append(struct ksm_rmap_item *rmap_item, rmap_item->mm->ksm_merging_pages++; } +static int try_to_merge_with_kernel_zero_page(struct ksm_rmap_item *rmap_item, + struct page *page) +{ + struct mm_struct *mm = rmap_item->mm; + int err = 0; + + /* + * It should not take ZERO_PAGE_FLAG because on one hand, + * get_next_rmap_item don't return zero pages' rmap_item. + * On the other hand, even if zero page was writen as + * anonymous page, rmap_item has been cleaned after + * stable_tree_search + */ + if (!WARN_ON_ONCE(rmap_item->address & ZERO_PAGE_FLAG)) { + struct vm_area_struct *vma; + + mmap_read_lock(mm); + vma = find_mergeable_vma(mm, rmap_item->address); + if (vma) { + err = try_to_merge_one_page(vma, page, + ZERO_PAGE(rmap_item->address)); + if (!err) + rmap_item->address |= ZERO_PAGE_FLAG; + } else { + /* If the vma is out of date, we do not need to continue. */ + err = 0; + } + mmap_read_unlock(mm); + } + + return err; +} + /* * cmp_and_merge_page - first see if page can be merged into the stable tree; * if not, compare checksum to previous and if it's the same, see if page can @@ -2054,7 +2131,6 @@ static void stable_tree_append(struct ksm_rmap_item *rmap_item, */ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_item) { - struct mm_struct *mm = rmap_item->mm; struct ksm_rmap_item *tree_rmap_item; struct page *tree_page = NULL; struct ksm_stable_node *stable_node; @@ -2091,6 +2167,7 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite } remove_rmap_item_from_tree(rmap_item); + clean_rmap_item_zero_flag(rmap_item); if (kpage) { if (PTR_ERR(kpage) == -EBUSY) @@ -2127,29 +2204,16 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite * Same checksum as an empty page. We attempt to merge it with the * appropriate zero page if the user enabled this via sysfs. */ - if (ksm_use_zero_pages && (checksum == zero_checksum)) { - struct vm_area_struct *vma; - - mmap_read_lock(mm); - vma = find_mergeable_vma(mm, rmap_item->address); - if (vma) { - err = try_to_merge_one_page(vma, page, - ZERO_PAGE(rmap_item->address)); - } else { + if (ksm_use_zero_pages) { + if (checksum == zero_checksum) /* - * If the vma is out of date, we do not need to - * continue. + * In case of failure, the page was not really empty, so we + * need to continue. Otherwise we're done. */ - err = 0; - } - mmap_read_unlock(mm); - /* - * In case of failure, the page was not really empty, so we - * need to continue. Otherwise we're done. - */ - if (!err) - return; + if (!try_to_merge_with_kernel_zero_page(rmap_item, page)) + return; } + tree_rmap_item = unstable_tree_search_insert(rmap_item, page, &tree_page); if (tree_rmap_item) { @@ -2229,6 +2293,7 @@ static struct ksm_rmap_item *try_to_get_old_rmap_item(unsigned long addr, * is ineligible or discarded, e.g. MADV_DONTNEED. */ remove_rmap_item_from_tree(rmap_item); + unshare_zero_pages(rmap_item); free_rmap_item(rmap_item); } @@ -2351,6 +2416,22 @@ static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) } if (is_zone_device_page(*page)) goto next_page; + if (is_zero_pfn(page_to_pfn(*page))) { + /* + * To monitor ksm zero pages which becomes non-anonymous, + * we have to save each rmap_item of zero pages by + * try_to_get_old_rmap_item() walking on + * ksm_scan.rmap_list, otherwise their rmap_items will be + * freed by the next turn of get_next_rmap_item(). The + * function get_next_rmap_item() will free all "skipped" + * rmap_items because it thinks its areas as UNMERGEABLE. + */ + rmap_item = try_to_get_old_rmap_item(ksm_scan.address, + ksm_scan.rmap_list); + if (rmap_item && (rmap_item->address & ZERO_PAGE_FLAG)) + ksm_scan.rmap_list = &rmap_item->rmap_list; + goto next_page; + } if (PageAnon(*page)) { flush_anon_page(vma, *page, ksm_scan.address); flush_dcache_page(*page); From 41b58fbdc1d8132cb85ff92bc89cf6e09926551f Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 30 Dec 2022 09:15:14 +0800 Subject: [PATCH 13/80] ksm: count all zero pages placed by KSM As pages_sharing and pages_shared don't include the number of zero pages merged by KSM, we cannot know how many pages are zero pages placed by KSM when enabling use_zero_pages, which leads to KSM not being transparent with all actual merged pages by KSM. In the early days of use_zero_pages, zero-pages was unable to get unshared by the ways like MADV_UNMERGEABLE so it's hard to count how many times one of those zeropages was then unmerged. But now, unsharing KSM-placed zero page accurately has been achieved, so we can easily count both how many times a page full of zeroes was merged with zero-page and how many times one of those pages was then unmerged. and so, it helps to estimate memory demands when each and every shared page could get unshared. So we add zero_pages_sharing under /sys/kernel/mm/ksm/ to show the number of all zero pages placed by KSM. Link: https://lkml.kernel.org/r/202212300915147801864@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Xuexin Jiang Signed-off-by: Andrew Morton --- mm/ksm.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/mm/ksm.c b/mm/ksm.c index 2897c34176993..7ec1de787ebed 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -276,6 +276,9 @@ static unsigned int zero_checksum __read_mostly; /* Whether to merge empty (zeroed) pages with actual zero pages */ static bool ksm_use_zero_pages __read_mostly; +/* The number of zero pages placed by KSM use_zero_pages */ +static unsigned long ksm_zero_pages_sharing; + #ifdef CONFIG_NUMA /* Zeroed when merging across nodes is not allowed */ static unsigned int ksm_merge_across_nodes = 1; @@ -789,8 +792,10 @@ static struct page *get_ksm_page(struct ksm_stable_node *stable_node, */ static inline void clean_rmap_item_zero_flag(struct ksm_rmap_item *rmap_item) { - if (rmap_item->address & ZERO_PAGE_FLAG) + if (rmap_item->address & ZERO_PAGE_FLAG) { + ksm_zero_pages_sharing--; rmap_item->address &= PAGE_MASK; + } } /* Only called when rmap_item is going to be freed */ @@ -2108,8 +2113,10 @@ static int try_to_merge_with_kernel_zero_page(struct ksm_rmap_item *rmap_item, if (vma) { err = try_to_merge_one_page(vma, page, ZERO_PAGE(rmap_item->address)); - if (!err) + if (!err) { rmap_item->address |= ZERO_PAGE_FLAG; + ksm_zero_pages_sharing++; + } } else { /* If the vma is out of date, we do not need to continue. */ err = 0; @@ -3228,6 +3235,13 @@ static ssize_t pages_volatile_show(struct kobject *kobj, } KSM_ATTR_RO(pages_volatile); +static ssize_t zero_pages_sharing_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sysfs_emit(buf, "%ld\n", ksm_zero_pages_sharing); +} +KSM_ATTR_RO(zero_pages_sharing); + static ssize_t stable_node_dups_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -3283,6 +3297,7 @@ static struct attribute *ksm_attrs[] = { &pages_sharing_attr.attr, &pages_unshared_attr.attr, &pages_volatile_attr.attr, + &zero_pages_sharing_attr.attr, &full_scans_attr.attr, #ifdef CONFIG_NUMA &merge_across_nodes_attr.attr, From 37f5860def48c50e6c131722803764f4ec35ebcd Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 30 Dec 2022 09:16:29 +0800 Subject: [PATCH 14/80] ksm: count zero pages for each process As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merged by KSM. To let users accurately estimate their memory demands when unsharing KSM zero-pages, it's necessary to show KSM zero- pages per process. Since unsharing zero pages placed by KSM accurately is achieved, then tracking empty pages merging and unmerging is not a difficult thing any longer. Since we already have /proc//ksm_stat, just add the information of zero_pages_sharing in it. Link: https://lkml.kernel.org/r/202212300916292181912@zte.com.cn Signed-off-by: xu xin Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Xuexin Jiang Cc: Xiaokai Ran Cc: Yang Yang Signed-off-by: Andrew Morton --- fs/proc/base.c | 1 + include/linux/mm_types.h | 7 ++++++- mm/ksm.c | 2 ++ 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 9e479d7d202b1..ac9ebe972be0b 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3207,6 +3207,7 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, mm = get_task_mm(task); if (mm) { seq_printf(m, "ksm_rmap_items %lu\n", mm->ksm_rmap_items); + seq_printf(m, "zero_pages_sharing %lu\n", mm->ksm_zero_pages_sharing); mmput(mm); } diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 56753d0f096d0..3cd60243c6252 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -729,7 +729,7 @@ struct mm_struct { #ifdef CONFIG_KSM /* * Represent how many pages of this process are involved in KSM - * merging. + * merging (not including ksm_zero_pages_sharing). */ unsigned long ksm_merging_pages; /* @@ -737,6 +737,11 @@ struct mm_struct { * including merged and not merged. */ unsigned long ksm_rmap_items; + /* + * Represent how many empty pages are merged with kernel zero + * pages when enabling KSM use_zero_pages. + */ + unsigned long ksm_zero_pages_sharing; #endif #ifdef CONFIG_LRU_GEN struct { diff --git a/mm/ksm.c b/mm/ksm.c index 7ec1de787ebed..31de9252f0452 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -794,6 +794,7 @@ static inline void clean_rmap_item_zero_flag(struct ksm_rmap_item *rmap_item) { if (rmap_item->address & ZERO_PAGE_FLAG) { ksm_zero_pages_sharing--; + rmap_item->mm->ksm_zero_pages_sharing--; rmap_item->address &= PAGE_MASK; } } @@ -2116,6 +2117,7 @@ static int try_to_merge_with_kernel_zero_page(struct ksm_rmap_item *rmap_item, if (!err) { rmap_item->address |= ZERO_PAGE_FLAG; ksm_zero_pages_sharing++; + rmap_item->mm->ksm_zero_pages_sharing++; } } else { /* If the vma is out of date, we do not need to continue. */ From a87b44dfa86cc4582e6589e4f7ca4094c0b19697 Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 30 Dec 2022 09:17:28 +0800 Subject: [PATCH 15/80] ksm: add zero_pages_sharing documentation When enabling use_zero_pages, pages_sharing cannot represent how much memory saved indeed. zero_pages_sharing + pages_sharing does. add the description of zero_pages_sharing. Link: https://lkml.kernel.org/r/202212300917284911971@zte.com.cn Signed-off-by: xu xin Cc: Xiaokai Ran Cc: Yang Yang Cc: Jiang Xuexin Cc: Claudio Imbrenda Cc: David Hildenbrand Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/ksm.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index fb6ba2002a4b2..f160f9487a90f 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -173,6 +173,13 @@ stable_node_chains the number of KSM pages that hit the ``max_page_sharing`` limit stable_node_dups number of duplicated KSM pages +zero_pages_sharing + how many empty pages are sharing kernel zero page(s) instead of + with each other as it would happen normally. Only effective when + enabling ``use_zero_pages`` knob. + +When enabling ``use_zero_pages``, the sum of ``pages_sharing`` + +``zero_pages_sharing`` represents how much really saved by KSM. A high ratio of ``pages_sharing`` to ``pages_shared`` indicates good sharing, but a high ratio of ``pages_unshared`` to ``pages_sharing`` From c6fac37d24d833d2ba995d41ee613b820c348f8c Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 30 Dec 2022 09:18:47 +0800 Subject: [PATCH 16/80] selftest: add testing unsharing and counting ksm zero page Add a function test_unmerge_zero_page() to test the functionality on unsharing and counting ksm-placed zero pages and counting of this patch series. test_unmerge_zero_page() actually contains three subjct test objects: 1) whether the count of ksm zero page can react correctly to cow (copy on write); 2) whether the count of ksm zero page can react correctly to unmerge; 3) whether ksm zero pages are really unmerged. Link: https://lkml.kernel.org/r/202212300918477352037@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Xuexin Jiang Signed-off-by: Andrew Morton --- .../selftests/mm/ksm_functional_tests.c | 103 +++++++++++++++++- 1 file changed, 99 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c index d8b5b49304121..6acbd08e73e7b 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -27,6 +27,8 @@ static int ksm_fd; static int ksm_full_scans_fd; +static int ksm_zero_pages_fd; +static int ksm_use_zero_pages_fd; static int pagemap_fd; static size_t pagesize; @@ -57,6 +59,22 @@ static bool range_maps_duplicates(char *addr, unsigned long size) return false; } +static bool check_ksm_zero_pages_count(unsigned long zero_size) +{ + unsigned long pages_expected = zero_size / (4 * KiB); + char buf[20]; + ssize_t read_size; + unsigned long ksm_zero_pages; + + read_size = pread(ksm_zero_pages_fd, buf, sizeof(buf) - 1, 0); + if (read_size < 0) + return -errno; + buf[read_size] = 0; + ksm_zero_pages = strtol(buf, NULL, 10); + + return ksm_zero_pages == pages_expected; +} + static long ksm_get_full_scans(void) { char buf[10]; @@ -70,15 +88,12 @@ static long ksm_get_full_scans(void) return strtol(buf, NULL, 10); } -static int ksm_merge(void) +static int wait_two_full_scans(void) { long start_scans, end_scans; - /* Wait for two full scans such that any possible merging happened. */ start_scans = ksm_get_full_scans(); if (start_scans < 0) - return start_scans; - if (write(ksm_fd, "1", 1) != 1) return -errno; do { end_scans = ksm_get_full_scans(); @@ -89,6 +104,34 @@ static int ksm_merge(void) return 0; } +static inline int ksm_merge(void) +{ + /* Wait for two full scans such that any possible merging happened. */ + if (write(ksm_fd, "1", 1) != 1) + return -errno; + return wait_two_full_scans(); +} + +static inline int make_cow(char *map, char val, unsigned long size) +{ + + memset(map, val, size); + return wait_two_full_scans(); +} + +static int unmerge_zero_page(char *start, unsigned long size) +{ + int ret; + + ret = madvise(start, size, MADV_UNMERGEABLE); + if (ret) { + ksft_test_result_fail("MADV_UNMERGEABLE failed\n"); + return ret; + } + + return wait_two_full_scans(); +} + static char *mmap_and_merge_range(char val, unsigned long size) { char *map; @@ -146,6 +189,56 @@ static void test_unmerge(void) munmap(map, size); } +static void test_unmerge_zero_pages(void) +{ + const unsigned int size = 2 * MiB; + char *map; + + ksft_print_msg("[RUN] %s\n", __func__); + + /* Confirm the interfaces*/ + ksm_zero_pages_fd = open("/sys/kernel/mm/ksm/zero_pages_sharing", O_RDONLY); + if (ksm_zero_pages_fd < 0) { + ksft_test_result_skip("open(\"/sys/kernel/mm/ksm/zero_pages_sharing\") failed\n"); + return; + } + ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR); + if (ksm_use_zero_pages_fd < 0) { + ksft_test_result_skip("open \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); + return; + } + if (write(ksm_use_zero_pages_fd, "1", 1) != 1) { + ksft_test_result_skip("write \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); + return; + } + + /* Mmap zero pages*/ + map = mmap_and_merge_range(0x00, size); + + /* Case 1: make Writing on ksm zero pages (COW) */ + if (make_cow(map, 0xcf, size / 2)) { + ksft_test_result_fail("COW failed\n"); + goto unmap; + } + ksft_test_result(check_ksm_zero_pages_count(size / 2), + "zero page count react to cow\n"); + + /* Case 2: Call madvise(xxx, MADV_UNMERGEABLE)*/ + if (unmerge_zero_page(map + size / 2, size / 4)) { + ksft_test_result_fail("unmerge_zero_page failed\n"); + goto unmap; + } + ksft_test_result(check_ksm_zero_pages_count(size / 4), + "zero page count react to unmerge\n"); + + /*Check if ksm pages are really unmerged */ + ksft_test_result(!range_maps_duplicates(map + size / 2, size / 4), + "KSM zero pages were unmerged\n"); + +unmap: + munmap(map, size); +} + static void test_unmerge_discarded(void) { const unsigned int size = 2 * MiB; @@ -261,11 +354,13 @@ int main(int argc, char **argv) ksm_full_scans_fd = open("/sys/kernel/mm/ksm/full_scans", O_RDONLY); if (ksm_full_scans_fd < 0) ksft_exit_skip("open(\"/sys/kernel/mm/ksm/full_scans\") failed\n"); + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); if (pagemap_fd < 0) ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n"); test_unmerge(); + test_unmerge_zero_pages(); test_unmerge_discarded(); #ifdef __NR_userfaultfd test_unmerge_uffd_wp(); From ce71d216ac3662f8dc68fddb195aaa520cc02e47 Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 10 Feb 2023 09:21:57 +0800 Subject: [PATCH 17/80] selftest-add-testing-unsharing-and-counting-ksm-zero-page-v6 v5->v6: According to David's suggestions, the following changes are made: 1) Rename check_ksm_zero_pages_count() -> ksm_get_zero_pages(), and do the comparison outside. 2) Open all global fd from main() rather than the test case. 3) Remove COW-related test codes and focus on explicit unmerging here. 4) Add some coments to explain why wait_two_full_scans is required. 5) Clean up some unneed changes. Link: https://lkml.kernel.org/r/202302100921574141612@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Cc: Claudio Imbrenda Cc: David Hildenbrand Cc: Xuexin Jiang Signed-off-by: Andrew Morton --- .../selftests/mm/ksm_functional_tests.c | 47 ++++++++----------- 1 file changed, 20 insertions(+), 27 deletions(-) diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c index 6acbd08e73e7b..05048ebc24d81 100644 --- a/tools/testing/selftests/mm/ksm_functional_tests.c +++ b/tools/testing/selftests/mm/ksm_functional_tests.c @@ -24,6 +24,7 @@ #define KiB 1024u #define MiB (1024 * KiB) +#define PageSize (4 * KiB) static int ksm_fd; static int ksm_full_scans_fd; @@ -59,9 +60,8 @@ static bool range_maps_duplicates(char *addr, unsigned long size) return false; } -static bool check_ksm_zero_pages_count(unsigned long zero_size) +static long ksm_get_zero_pages(void) { - unsigned long pages_expected = zero_size / (4 * KiB); char buf[20]; ssize_t read_size; unsigned long ksm_zero_pages; @@ -72,7 +72,7 @@ static bool check_ksm_zero_pages_count(unsigned long zero_size) buf[read_size] = 0; ksm_zero_pages = strtol(buf, NULL, 10); - return ksm_zero_pages == pages_expected; + return ksm_zero_pages; } static long ksm_get_full_scans(void) @@ -109,13 +109,7 @@ static inline int ksm_merge(void) /* Wait for two full scans such that any possible merging happened. */ if (write(ksm_fd, "1", 1) != 1) return -errno; - return wait_two_full_scans(); -} -static inline int make_cow(char *map, char val, unsigned long size) -{ - - memset(map, val, size); return wait_two_full_scans(); } @@ -129,6 +123,12 @@ static int unmerge_zero_page(char *start, unsigned long size) return ret; } + /* + * Wait for two full scans such that any possible unmerging of zero + * pages happened. Why? Because the unmerge action of zero pages is not + * done in the context of madvise(), but in the context of + * unshare_zero_pages() of the ksmd thread. + */ return wait_two_full_scans(); } @@ -193,16 +193,15 @@ static void test_unmerge_zero_pages(void) { const unsigned int size = 2 * MiB; char *map; + unsigned long pages_expected; ksft_print_msg("[RUN] %s\n", __func__); /* Confirm the interfaces*/ - ksm_zero_pages_fd = open("/sys/kernel/mm/ksm/zero_pages_sharing", O_RDONLY); if (ksm_zero_pages_fd < 0) { ksft_test_result_skip("open(\"/sys/kernel/mm/ksm/zero_pages_sharing\") failed\n"); return; } - ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR); if (ksm_use_zero_pages_fd < 0) { ksft_test_result_skip("open \"/sys/kernel/mm/ksm/use_zero_pages\" failed\n"); return; @@ -214,27 +213,20 @@ static void test_unmerge_zero_pages(void) /* Mmap zero pages*/ map = mmap_and_merge_range(0x00, size); + if (map == MAP_FAILED) + return; - /* Case 1: make Writing on ksm zero pages (COW) */ - if (make_cow(map, 0xcf, size / 2)) { - ksft_test_result_fail("COW failed\n"); + if (unmerge_zero_page(map + size / 2, size / 2)) goto unmap; - } - ksft_test_result(check_ksm_zero_pages_count(size / 2), - "zero page count react to cow\n"); - /* Case 2: Call madvise(xxx, MADV_UNMERGEABLE)*/ - if (unmerge_zero_page(map + size / 2, size / 4)) { - ksft_test_result_fail("unmerge_zero_page failed\n"); - goto unmap; - } - ksft_test_result(check_ksm_zero_pages_count(size / 4), + /* Check if zero_pages_sharing can be update correctly when unmerge */ + pages_expected = (size / 2) / PageSize; + ksft_test_result(pages_expected == ksm_get_zero_pages(), "zero page count react to unmerge\n"); - /*Check if ksm pages are really unmerged */ - ksft_test_result(!range_maps_duplicates(map + size / 2, size / 4), + /* Check if ksm zero pages are really unmerged */ + ksft_test_result(!range_maps_duplicates(map + size / 2, size / 2), "KSM zero pages were unmerged\n"); - unmap: munmap(map, size); } @@ -354,10 +346,11 @@ int main(int argc, char **argv) ksm_full_scans_fd = open("/sys/kernel/mm/ksm/full_scans", O_RDONLY); if (ksm_full_scans_fd < 0) ksft_exit_skip("open(\"/sys/kernel/mm/ksm/full_scans\") failed\n"); - pagemap_fd = open("/proc/self/pagemap", O_RDONLY); if (pagemap_fd < 0) ksft_exit_skip("open(\"/proc/self/pagemap\") failed\n"); + ksm_zero_pages_fd = open("/sys/kernel/mm/ksm/zero_pages_sharing", O_RDONLY); + ksm_use_zero_pages_fd = open("/sys/kernel/mm/ksm/use_zero_pages", O_RDWR); test_unmerge(); test_unmerge_zero_pages(); From b4c3c22b692d36a7e7b9f1489eda5f1fd5fbd9eb Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:14 -0800 Subject: [PATCH 18/80] dmapool: add alloc/free performance test Patch series "dmapool enhancements", v4. Time spent in dma_pool alloc/free increases linearly with the number of pages backing the pool. We can reduce this to constant time with minor changes to how free pages are tracked. This patch (of 12): Provide a module that allocates and frees many blocks of various sizes and report how long it takes. This is intended to provide a consistent way to measure how changes to the dma_pool_alloc/free routines affect timing. Link: https://lkml.kernel.org/r/20230126215125.4069751-1-kbusch@meta.com Link: https://lkml.kernel.org/r/20230126215125.4069751-2-kbusch@meta.com Signed-off-by: Keith Busch Cc: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/Kconfig | 9 +++ mm/Makefile | 1 + mm/dmapool_test.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 157 insertions(+) create mode 100644 mm/dmapool_test.c diff --git a/mm/Kconfig b/mm/Kconfig index 4751031f3f052..ca98b2072df5c 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1100,6 +1100,15 @@ comment "GUP_TEST needs to have DEBUG_FS enabled" config GUP_GET_PXX_LOW_HIGH bool +config DMAPOOL_TEST + tristate "Enable a module to run time tests on dma_pool" + depends on HAS_DMA + help + Provides a test module that will allocate and free many blocks of + various sizes and report how long it takes. This is intended to + provide a consistent way to measure how changes to the + dma_pool_alloc/free routines affect performance. + config ARCH_HAS_PTE_SPECIAL bool diff --git a/mm/Makefile b/mm/Makefile index 8e105e5b3e293..3a08f5d7b1782 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -103,6 +103,7 @@ obj-$(CONFIG_MEMCG) += swap_cgroup.o endif obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o obj-$(CONFIG_GUP_TEST) += gup_test.o +obj-$(CONFIG_DMAPOOL_TEST) += dmapool_test.o obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o diff --git a/mm/dmapool_test.c b/mm/dmapool_test.c new file mode 100644 index 0000000000000..370fb9e209eff --- /dev/null +++ b/mm/dmapool_test.c @@ -0,0 +1,147 @@ +#include +#include +#include +#include +#include +#include +#include + +#define NR_TESTS (100) + +struct dma_pool_pair { + dma_addr_t dma; + void *v; +}; + +struct dmapool_parms { + size_t size; + size_t align; + size_t boundary; +}; + +static const struct dmapool_parms pool_parms[] = { + { .size = 16, .align = 16, .boundary = 0 }, + { .size = 64, .align = 64, .boundary = 0 }, + { .size = 256, .align = 256, .boundary = 0 }, + { .size = 1024, .align = 1024, .boundary = 0 }, + { .size = 4096, .align = 4096, .boundary = 0 }, + { .size = 68, .align = 32, .boundary = 4096 }, +}; + +static struct dma_pool *pool; +static struct device test_dev; +static u64 dma_mask; + +static inline int nr_blocks(int size) +{ + return clamp_t(int, (PAGE_SIZE / size) * 512, 1024, 8192); +} + +static int dmapool_test_alloc(struct dma_pool_pair *p, int blocks) +{ + int i; + + for (i = 0; i < blocks; i++) { + p[i].v = dma_pool_alloc(pool, GFP_KERNEL, + &p[i].dma); + if (!p[i].v) + goto pool_fail; + } + + for (i = 0; i < blocks; i++) + dma_pool_free(pool, p[i].v, p[i].dma); + + return 0; + +pool_fail: + for (--i; i >= 0; i--) + dma_pool_free(pool, p[i].v, p[i].dma); + return -ENOMEM; +} + +static int dmapool_test_block(const struct dmapool_parms *parms) +{ + int blocks = nr_blocks(parms->size); + ktime_t start_time, end_time; + struct dma_pool_pair *p; + int i, ret; + + p = kcalloc(blocks, sizeof(*p), GFP_KERNEL); + if (!p) + return -ENOMEM; + + pool = dma_pool_create("test pool", &test_dev, parms->size, + parms->align, parms->boundary); + if (!pool) { + ret = -ENOMEM; + goto free_pairs; + } + + start_time = ktime_get(); + for (i = 0; i < NR_TESTS; i++) { + ret = dmapool_test_alloc(p, blocks); + if (ret) + goto free_pool; + if (need_resched()) + cond_resched(); + } + end_time = ktime_get(); + + printk("dmapool test: size:%-4zu align:%-4zu blocks:%-4d time:%llu\n", + parms->size, parms->align, blocks, + ktime_us_delta(end_time, start_time)); + +free_pool: + dma_pool_destroy(pool); +free_pairs: + kfree(p); + return ret; +} + +static void dmapool_test_release(struct device *dev) +{ +} + +static int dmapool_checks(void) +{ + int i, ret; + + ret = dev_set_name(&test_dev, "dmapool-test"); + if (ret) + return ret; + + ret = device_register(&test_dev); + if (ret) { + printk("%s: register failed:%d\n", __func__, ret); + goto put_device; + } + + test_dev.release = dmapool_test_release; + set_dma_ops(&test_dev, NULL); + test_dev.dma_mask = &dma_mask; + ret = dma_set_mask_and_coherent(&test_dev, DMA_BIT_MASK(64)); + if (ret) { + printk("%s: mask failed:%d\n", __func__, ret); + goto del_device; + } + + for (i = 0; i < ARRAY_SIZE(pool_parms); i++) { + ret = dmapool_test_block(&pool_parms[i]); + if (ret) + break; + } + +del_device: + device_del(&test_dev); +put_device: + put_device(&test_dev); + return ret; +} + +static void dmapool_exit(void) +{ +} + +module_init(dmapool_checks); +module_exit(dmapool_exit); +MODULE_LICENSE("GPL"); From c187a71c5697f55731a5aa91b150fea4d0220143 Mon Sep 17 00:00:00 2001 From: Tony Battersby Date: Thu, 26 Jan 2023 13:51:15 -0800 Subject: [PATCH 19/80] dmapool: remove checks for dev == NULL dmapool originally tried to support pools without a device because dma_alloc_coherent() supports allocations without a device. But nobody ended up using dma pools without a device, and trying to do so will result in an oops. So remove the checks for pool->dev == NULL since they are unneeded bloat. [kbusch@kernel.org: add check for null dev on create] Link: https://lkml.kernel.org/r/20230126215125.4069751-3-kbusch@meta.com Signed-off-by: Tony Battersby Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/dmapool.c | 45 ++++++++++++++------------------------------- 1 file changed, 14 insertions(+), 31 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index a7eb5d0eb2da7..559207e1c3339 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -134,6 +134,9 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, size_t allocation; bool empty = false; + if (!dev) + return NULL; + if (align == 0) align = 1; else if (align & (align - 1)) @@ -275,7 +278,7 @@ void dma_pool_destroy(struct dma_pool *pool) mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); list_del(&pool->pools); - if (pool->dev && list_empty(&pool->dev->dma_pools)) + if (list_empty(&pool->dev->dma_pools)) empty = true; mutex_unlock(&pools_lock); if (empty) @@ -284,12 +287,8 @@ void dma_pool_destroy(struct dma_pool *pool) list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { if (is_page_busy(page)) { - if (pool->dev) - dev_err(pool->dev, "%s %s, %p busy\n", __func__, - pool->name, page->vaddr); - else - pr_err("%s %s, %p busy\n", __func__, - pool->name, page->vaddr); + dev_err(pool->dev, "%s %s, %p busy\n", __func__, + pool->name, page->vaddr); /* leak the still-in-use consistent memory */ list_del(&page->page_list); kfree(page); @@ -351,12 +350,8 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, for (i = sizeof(page->offset); i < pool->size; i++) { if (data[i] == POOL_POISON_FREED) continue; - if (pool->dev) - dev_err(pool->dev, "%s %s, %p (corrupted)\n", - __func__, pool->name, retval); - else - pr_err("%s %s, %p (corrupted)\n", - __func__, pool->name, retval); + dev_err(pool->dev, "%s %s, %p (corrupted)\n", + __func__, pool->name, retval); /* * Dump the first 4 bytes even if they are not @@ -411,12 +406,8 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) page = pool_find_page(pool, dma); if (!page) { spin_unlock_irqrestore(&pool->lock, flags); - if (pool->dev) - dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", - __func__, pool->name, vaddr, &dma); - else - pr_err("%s %s, %p/%pad (bad dma)\n", - __func__, pool->name, vaddr, &dma); + dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", + __func__, pool->name, vaddr, &dma); return; } @@ -426,12 +417,8 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) #ifdef DMAPOOL_DEBUG if ((dma - page->dma) != offset) { spin_unlock_irqrestore(&pool->lock, flags); - if (pool->dev) - dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", - __func__, pool->name, vaddr, &dma); - else - pr_err("%s %s, %p (bad vaddr)/%pad\n", - __func__, pool->name, vaddr, &dma); + dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", + __func__, pool->name, vaddr, &dma); return; } { @@ -442,12 +429,8 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) continue; } spin_unlock_irqrestore(&pool->lock, flags); - if (pool->dev) - dev_err(pool->dev, "%s %s, dma %pad already free\n", - __func__, pool->name, &dma); - else - pr_err("%s %s, dma %pad already free\n", - __func__, pool->name, &dma); + dev_err(pool->dev, "%s %s, dma %pad already free\n", + __func__, pool->name, &dma); return; } } From 9c88dc987330c7d3dc2f7fc898128c3a7f45fe44 Mon Sep 17 00:00:00 2001 From: Tony Battersby Date: Thu, 26 Jan 2023 13:51:16 -0800 Subject: [PATCH 20/80] dmapool: use sysfs_emit() instead of scnprintf() Use sysfs_emit instead of scnprintf, snprintf or sprintf. Link: https://lkml.kernel.org/r/20230126215125.4069751-4-kbusch@meta.com Signed-off-by: Tony Battersby Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/dmapool.c | 23 +++++++---------------- 1 file changed, 7 insertions(+), 16 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 559207e1c3339..20616b760bb9c 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -64,18 +64,11 @@ static DEFINE_MUTEX(pools_reg_lock); static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf) { - unsigned temp; - unsigned size; - char *next; + int size; struct dma_page *page; struct dma_pool *pool; - next = buf; - size = PAGE_SIZE; - - temp = scnprintf(next, size, "poolinfo - 0.1\n"); - size -= temp; - next += temp; + size = sysfs_emit(buf, "poolinfo - 0.1\n"); mutex_lock(&pools_lock); list_for_each_entry(pool, &dev->dma_pools, pools) { @@ -90,16 +83,14 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha spin_unlock_irq(&pool->lock); /* per-pool info, no real statistics yet */ - temp = scnprintf(next, size, "%-16s %4u %4zu %4zu %2u\n", - pool->name, blocks, - pages * (pool->allocation / pool->size), - pool->size, pages); - size -= temp; - next += temp; + size += sysfs_emit_at(buf, size, "%-16s %4u %4zu %4zu %2u\n", + pool->name, blocks, + pages * (pool->allocation / pool->size), + pool->size, pages); } mutex_unlock(&pools_lock); - return PAGE_SIZE - size; + return size; } static DEVICE_ATTR_RO(pools); From 45cd251a07202d32ba8d348b1e5e3f133dd4392f Mon Sep 17 00:00:00 2001 From: Tony Battersby Date: Thu, 26 Jan 2023 13:51:17 -0800 Subject: [PATCH 21/80] dmapool: cleanup integer types To represent the size of a single allocation, dmapool currently uses 'unsigned int' in some places and 'size_t' in other places. Standardize on 'unsigned int' to reduce overhead, but use 'size_t' when counting all the blocks in the entire pool. Link: https://lkml.kernel.org/r/20230126215125.4069751-5-kbusch@meta.com Signed-off-by: Tony Battersby Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/dmapool.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 20616b760bb9c..ee993bb59fc27 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -43,10 +43,10 @@ struct dma_pool { /* the pool */ struct list_head page_list; spinlock_t lock; - size_t size; struct device *dev; - size_t allocation; - size_t boundary; + unsigned int size; + unsigned int allocation; + unsigned int boundary; char name[32]; struct list_head pools; }; @@ -73,7 +73,7 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha mutex_lock(&pools_lock); list_for_each_entry(pool, &dev->dma_pools, pools) { unsigned pages = 0; - unsigned blocks = 0; + size_t blocks = 0; spin_lock_irq(&pool->lock); list_for_each_entry(page, &pool->page_list, page_list) { @@ -83,9 +83,10 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha spin_unlock_irq(&pool->lock); /* per-pool info, no real statistics yet */ - size += sysfs_emit_at(buf, size, "%-16s %4u %4zu %4zu %2u\n", + size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2u\n", pool->name, blocks, - pages * (pool->allocation / pool->size), + (size_t) pages * + (pool->allocation / pool->size), pool->size, pages); } mutex_unlock(&pools_lock); @@ -133,7 +134,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, else if (align & (align - 1)) return NULL; - if (size == 0) + if (size == 0 || size > INT_MAX) return NULL; else if (size < 4) size = 4; @@ -146,6 +147,8 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, else if ((boundary < size) || (boundary & (boundary - 1))) return NULL; + boundary = min(boundary, allocation); + retval = kmalloc(sizeof(*retval), GFP_KERNEL); if (!retval) return retval; @@ -306,7 +309,7 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, { unsigned long flags; struct dma_page *page; - size_t offset; + unsigned int offset; void *retval; might_alloc(mem_flags); From f9ce55c9871b4bff27b472f7fc2a06a0790e6ee0 Mon Sep 17 00:00:00 2001 From: Tony Battersby Date: Thu, 26 Jan 2023 13:51:18 -0800 Subject: [PATCH 22/80] dmapool: speedup DMAPOOL_DEBUG with init_on_alloc Avoid double-memset of the same allocated memory in dma_pool_alloc() when both DMAPOOL_DEBUG is enabled and init_on_alloc=1. Link: https://lkml.kernel.org/r/20230126215125.4069751-6-kbusch@meta.com Signed-off-by: Tony Battersby Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/dmapool.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index ee993bb59fc27..eaed3ffb42aa8 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -356,7 +356,7 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, break; } } - if (!(mem_flags & __GFP_ZERO)) + if (!want_init_on_alloc(mem_flags)) memset(retval, POOL_POISON_ALLOCATED, pool->size); #endif spin_unlock_irqrestore(&pool->lock, flags); From 8fb7bb53e2ea02c2fc492a0e64d88283a4cb5817 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:19 -0800 Subject: [PATCH 23/80] dmapool: move debug code to own functions Clean up the normal path by moving the debug code outside it. Link: https://lkml.kernel.org/r/20230126215125.4069751-7-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 128 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 77 insertions(+), 51 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index eaed3ffb42aa8..30b069e999968 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -96,6 +96,78 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha static DEVICE_ATTR_RO(pools); +#ifdef DMAPOOL_DEBUG +static void pool_check_block(struct dma_pool *pool, void *retval, + unsigned int offset, gfp_t mem_flags) +{ + int i; + u8 *data = retval; + /* page->offset is stored in first 4 bytes */ + for (i = sizeof(offset); i < pool->size; i++) { + if (data[i] == POOL_POISON_FREED) + continue; + dev_err(pool->dev, "%s %s, %p (corrupted)\n", + __func__, pool->name, retval); + + /* + * Dump the first 4 bytes even if they are not + * POOL_POISON_FREED + */ + print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, + data, pool->size, 1); + break; + } + if (!want_init_on_alloc(mem_flags)) + memset(retval, POOL_POISON_ALLOCATED, pool->size); +} + +static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, + void *vaddr, dma_addr_t dma) +{ + unsigned int offset = vaddr - page->vaddr; + unsigned int chain = page->offset; + + if ((dma - page->dma) != offset) { + dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", + __func__, pool->name, vaddr, &dma); + return true; + } + + while (chain < pool->allocation) { + if (chain != offset) { + chain = *(int *)(page->vaddr + chain); + continue; + } + dev_err(pool->dev, "%s %s, dma %pad already free\n", + __func__, pool->name, &dma); + return true; + } + memset(vaddr, POOL_POISON_FREED, pool->size); + return false; +} + +static void pool_init_page(struct dma_pool *pool, struct dma_page *page) +{ + memset(page->vaddr, POOL_POISON_FREED, pool->allocation); +} +#else +static void pool_check_block(struct dma_pool *pool, void *retval, + unsigned int offset, gfp_t mem_flags) + +{ +} + +static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, + void *vaddr, dma_addr_t dma) +{ + return false; +} + +static void pool_init_page(struct dma_pool *pool, struct dma_page *page) +{ +} +#endif + /** * dma_pool_create - Creates a pool of consistent memory blocks, for dma. * @name: name of pool, for diagnostics @@ -223,9 +295,7 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, &page->dma, mem_flags); if (page->vaddr) { -#ifdef DMAPOOL_DEBUG - memset(page->vaddr, POOL_POISON_FREED, pool->allocation); -#endif + pool_init_page(pool, page); pool_initialise_page(pool, page); page->in_use = 0; page->offset = 0; @@ -245,9 +315,7 @@ static void pool_free_page(struct dma_pool *pool, struct dma_page *page) { dma_addr_t dma = page->dma; -#ifdef DMAPOOL_DEBUG - memset(page->vaddr, POOL_POISON_FREED, pool->allocation); -#endif + pool_init_page(pool, page); dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); list_del(&page->page_list); kfree(page); @@ -336,29 +404,7 @@ void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, page->offset = *(int *)(page->vaddr + offset); retval = offset + page->vaddr; *handle = offset + page->dma; -#ifdef DMAPOOL_DEBUG - { - int i; - u8 *data = retval; - /* page->offset is stored in first 4 bytes */ - for (i = sizeof(page->offset); i < pool->size; i++) { - if (data[i] == POOL_POISON_FREED) - continue; - dev_err(pool->dev, "%s %s, %p (corrupted)\n", - __func__, pool->name, retval); - - /* - * Dump the first 4 bytes even if they are not - * POOL_POISON_FREED - */ - print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, - data, pool->size, 1); - break; - } - } - if (!want_init_on_alloc(mem_flags)) - memset(retval, POOL_POISON_ALLOCATED, pool->size); -#endif + pool_check_block(pool, retval, offset, mem_flags); spin_unlock_irqrestore(&pool->lock, flags); if (want_init_on_alloc(mem_flags)) @@ -394,7 +440,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { struct dma_page *page; unsigned long flags; - unsigned int offset; spin_lock_irqsave(&pool->lock, flags); page = pool_find_page(pool, dma); @@ -405,35 +450,16 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) return; } - offset = vaddr - page->vaddr; if (want_init_on_free()) memset(vaddr, 0, pool->size); -#ifdef DMAPOOL_DEBUG - if ((dma - page->dma) != offset) { + if (pool_page_err(pool, page, vaddr, dma)) { spin_unlock_irqrestore(&pool->lock, flags); - dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", - __func__, pool->name, vaddr, &dma); return; } - { - unsigned int chain = page->offset; - while (chain < pool->allocation) { - if (chain != offset) { - chain = *(int *)(page->vaddr + chain); - continue; - } - spin_unlock_irqrestore(&pool->lock, flags); - dev_err(pool->dev, "%s %s, dma %pad already free\n", - __func__, pool->name, &dma); - return; - } - } - memset(vaddr, POOL_POISON_FREED, pool->size); -#endif page->in_use--; *(int *)vaddr = page->offset; - page->offset = offset; + page->offset = vaddr - page->vaddr; /* * Resist a temptation to do * if (!is_page_busy(page)) pool_free_page(pool, page); From fa3aa07995a206219a527fef106bd82e0998df32 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:20 -0800 Subject: [PATCH 24/80] dmapool: rearrange page alloc failure handling Handle the error in a condition so the good path can be in the normal flow. Link: https://lkml.kernel.org/r/20230126215125.4069751-8-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 30b069e999968..900f2afa363a9 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -292,17 +292,19 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) page = kmalloc(sizeof(*page), mem_flags); if (!page) return NULL; + page->vaddr = dma_alloc_coherent(pool->dev, pool->allocation, &page->dma, mem_flags); - if (page->vaddr) { - pool_init_page(pool, page); - pool_initialise_page(pool, page); - page->in_use = 0; - page->offset = 0; - } else { + if (!page->vaddr) { kfree(page); - page = NULL; + return NULL; } + + pool_init_page(pool, page); + pool_initialise_page(pool, page); + page->in_use = 0; + page->offset = 0; + return page; } From a1206c2e2940ae4a85cf6ddf43a96dd7461767b2 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:21 -0800 Subject: [PATCH 25/80] dmapool: consolidate page initialization Various fields of the dma pool are set in different places. Move it all to one function. Link: https://lkml.kernel.org/r/20230126215125.4069751-9-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 900f2afa363a9..9e98065a68b1f 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -274,6 +274,9 @@ static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) unsigned int offset = 0; unsigned int next_boundary = pool->boundary; + pool_init_page(pool, page); + page->in_use = 0; + page->offset = 0; do { unsigned int next = offset + pool->size; if (unlikely((next + pool->size) >= next_boundary)) { @@ -300,11 +303,7 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) return NULL; } - pool_init_page(pool, page); pool_initialise_page(pool, page); - page->in_use = 0; - page->offset = 0; - return page; } From 9f9e89ac6ecb736eb76445b8b1cf15dc02d702d3 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:22 -0800 Subject: [PATCH 26/80] dmapool: simplify freeing The actions for busy and not busy are mostly the same, so combine these and remove the unnecessary function. Also, the pool is about to be freed so there's no need to poison the page data since we only check for poison on alloc, which can't be done on a freed pool. Link: https://lkml.kernel.org/r/20230126215125.4069751-10-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 22 ++++++---------------- 1 file changed, 6 insertions(+), 16 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 9e98065a68b1f..4dea2a0dbd336 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -312,16 +312,6 @@ static inline bool is_page_busy(struct dma_page *page) return page->in_use != 0; } -static void pool_free_page(struct dma_pool *pool, struct dma_page *page) -{ - dma_addr_t dma = page->dma; - - pool_init_page(pool, page); - dma_free_coherent(pool->dev, pool->allocation, page->vaddr, dma); - list_del(&page->page_list); - kfree(page); -} - /** * dma_pool_destroy - destroys a pool of dma memory blocks. * @pool: dma pool that will be destroyed @@ -349,14 +339,14 @@ void dma_pool_destroy(struct dma_pool *pool) mutex_unlock(&pools_reg_lock); list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { - if (is_page_busy(page)) { + if (!is_page_busy(page)) + dma_free_coherent(pool->dev, pool->allocation, + page->vaddr, page->dma); + else dev_err(pool->dev, "%s %s, %p busy\n", __func__, pool->name, page->vaddr); - /* leak the still-in-use consistent memory */ - list_del(&page->page_list); - kfree(page); - } else - pool_free_page(pool, page); + list_del(&page->page_list); + kfree(page); } kfree(pool); From 87ee58cc869797cccb854671637274abb99f31e6 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:23 -0800 Subject: [PATCH 27/80] dmapool: don't memset on free twice If debug is enabled, dmapool will poison the range, so no need to clear it to 0 immediately before writing over it. Link: https://lkml.kernel.org/r/20230126215125.4069751-11-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 4dea2a0dbd336..21e6d362c7264 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -160,6 +160,8 @@ static void pool_check_block(struct dma_pool *pool, void *retval, static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, void *vaddr, dma_addr_t dma) { + if (want_init_on_free()) + memset(vaddr, 0, pool->size); return false; } @@ -441,8 +443,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) return; } - if (want_init_on_free()) - memset(vaddr, 0, pool->size); if (pool_page_err(pool, page, vaddr, dma)) { spin_unlock_irqrestore(&pool->lock, flags); return; From d9aa4a1a1334029342ab3ebe65586b5a76048884 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:24 -0800 Subject: [PATCH 28/80] dmapool: link blocks across pages The allocated dmapool pages are never freed for the lifetime of the pool. There is no need for the two level list+stack lookup for finding a free block since nothing is ever removed from the list. Just use a simple stack, reducing time complexity to constant. The implementation inserts the stack linking elements and the dma handle of the block within itself when freed. This means the smallest possible dmapool block is increased to at most 16 bytes to accommodate these fields, but there are no exisiting users requesting a dma pool smaller than that anyway. Removing the list has a significant change in performance. Using the kernel's micro-benchmarking self test: Before: # modprobe dmapool_test dmapool test: size:16 blocks:8192 time:57282 dmapool test: size:64 blocks:8192 time:172562 dmapool test: size:256 blocks:8192 time:789247 dmapool test: size:1024 blocks:2048 time:371823 dmapool test: size:4096 blocks:1024 time:362237 After: # modprobe dmapool_test dmapool test: size:16 blocks:8192 time:24997 dmapool test: size:64 blocks:8192 time:26584 dmapool test: size:256 blocks:8192 time:33542 dmapool test: size:1024 blocks:2048 time:9022 dmapool test: size:4096 blocks:1024 time:6045 The module test allocates quite a few blocks that may not accurately represent how these pools are used in real life. For a more marco level benchmark, running fio high-depth + high-batched on nvme, this patch shows submission and completion latency reduced by ~100usec each, 1% IOPs improvement, and perf record's time spent in dma_pool_alloc/free were reduced by half. Link: https://lkml.kernel.org/r/20230126215125.4069751-12-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 246 +++++++++++++++++++++++++-------------------------- 1 file changed, 119 insertions(+), 127 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index 21e6d362c7264..bb8893b4f4b96 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -15,7 +15,7 @@ * represented by the 'struct dma_pool' which keeps a doubly-linked list of * allocated pages. Each page in the page_list is split into blocks of at * least 'size' bytes. Free blocks are tracked in an unsorted singly-linked - * list of free blocks within the page. Used blocks aren't tracked, but we + * list of free blocks across all pages. Used blocks aren't tracked, but we * keep a count of how many are currently allocated from each page. */ @@ -40,9 +40,18 @@ #define DMAPOOL_DEBUG 1 #endif +struct dma_block { + struct dma_block *next_block; + dma_addr_t dma; +}; + struct dma_pool { /* the pool */ struct list_head page_list; spinlock_t lock; + struct dma_block *next_block; + size_t nr_blocks; + size_t nr_active; + size_t nr_pages; struct device *dev; unsigned int size; unsigned int allocation; @@ -55,8 +64,6 @@ struct dma_page { /* cacheable header for 'allocation' bytes */ struct list_head page_list; void *vaddr; dma_addr_t dma; - unsigned int in_use; - unsigned int offset; }; static DEFINE_MUTEX(pools_lock); @@ -64,30 +71,18 @@ static DEFINE_MUTEX(pools_reg_lock); static ssize_t pools_show(struct device *dev, struct device_attribute *attr, char *buf) { - int size; - struct dma_page *page; struct dma_pool *pool; + unsigned size; size = sysfs_emit(buf, "poolinfo - 0.1\n"); mutex_lock(&pools_lock); list_for_each_entry(pool, &dev->dma_pools, pools) { - unsigned pages = 0; - size_t blocks = 0; - - spin_lock_irq(&pool->lock); - list_for_each_entry(page, &pool->page_list, page_list) { - pages++; - blocks += page->in_use; - } - spin_unlock_irq(&pool->lock); - /* per-pool info, no real statistics yet */ - size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2u\n", - pool->name, blocks, - (size_t) pages * - (pool->allocation / pool->size), - pool->size, pages); + size += sysfs_emit_at(buf, size, "%-16s %4zu %4zu %4u %2zu\n", + pool->name, pool->nr_active, + pool->nr_blocks, pool->size, + pool->nr_pages); } mutex_unlock(&pools_lock); @@ -97,17 +92,17 @@ static ssize_t pools_show(struct device *dev, struct device_attribute *attr, cha static DEVICE_ATTR_RO(pools); #ifdef DMAPOOL_DEBUG -static void pool_check_block(struct dma_pool *pool, void *retval, - unsigned int offset, gfp_t mem_flags) +static void pool_check_block(struct dma_pool *pool, struct dma_block *block, + gfp_t mem_flags) { + u8 *data = (void *)block; int i; - u8 *data = retval; - /* page->offset is stored in first 4 bytes */ - for (i = sizeof(offset); i < pool->size; i++) { + + for (i = sizeof(struct dma_block); i < pool->size; i++) { if (data[i] == POOL_POISON_FREED) continue; - dev_err(pool->dev, "%s %s, %p (corrupted)\n", - __func__, pool->name, retval); + dev_err(pool->dev, "%s %s, %p (corrupted)\n", __func__, + pool->name, block); /* * Dump the first 4 bytes even if they are not @@ -117,31 +112,46 @@ static void pool_check_block(struct dma_pool *pool, void *retval, data, pool->size, 1); break; } + if (!want_init_on_alloc(mem_flags)) - memset(retval, POOL_POISON_ALLOCATED, pool->size); + memset(block, POOL_POISON_ALLOCATED, pool->size); +} + +static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) +{ + struct dma_page *page; + + list_for_each_entry(page, &pool->page_list, page_list) { + if (dma < page->dma) + continue; + if ((dma - page->dma) < pool->allocation) + return page; + } + return NULL; } -static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, - void *vaddr, dma_addr_t dma) +static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { - unsigned int offset = vaddr - page->vaddr; - unsigned int chain = page->offset; + struct dma_block *block = pool->next_block; + struct dma_page *page; - if ((dma - page->dma) != offset) { - dev_err(pool->dev, "%s %s, %p (bad vaddr)/%pad\n", + page = pool_find_page(pool, dma); + if (!page) { + dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", __func__, pool->name, vaddr, &dma); return true; } - while (chain < pool->allocation) { - if (chain != offset) { - chain = *(int *)(page->vaddr + chain); + while (block) { + if (block != vaddr) { + block = block->next_block; continue; } dev_err(pool->dev, "%s %s, dma %pad already free\n", __func__, pool->name, &dma); return true; } + memset(vaddr, POOL_POISON_FREED, pool->size); return false; } @@ -151,14 +161,12 @@ static void pool_init_page(struct dma_pool *pool, struct dma_page *page) memset(page->vaddr, POOL_POISON_FREED, pool->allocation); } #else -static void pool_check_block(struct dma_pool *pool, void *retval, - unsigned int offset, gfp_t mem_flags) - +static void pool_check_block(struct dma_pool *pool, struct dma_block *block, + gfp_t mem_flags) { } -static bool pool_page_err(struct dma_pool *pool, struct dma_page *page, - void *vaddr, dma_addr_t dma) +static bool pool_block_err(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { if (want_init_on_free()) memset(vaddr, 0, pool->size); @@ -170,6 +178,26 @@ static void pool_init_page(struct dma_pool *pool, struct dma_page *page) } #endif +static struct dma_block *pool_block_pop(struct dma_pool *pool) +{ + struct dma_block *block = pool->next_block; + + if (block) { + pool->next_block = block->next_block; + pool->nr_active++; + } + return block; +} + +static void pool_block_push(struct dma_pool *pool, struct dma_block *block, + dma_addr_t dma) +{ + block->dma = dma; + block->next_block = pool->next_block; + pool->next_block = block; +} + + /** * dma_pool_create - Creates a pool of consistent memory blocks, for dma. * @name: name of pool, for diagnostics @@ -210,8 +238,8 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, if (size == 0 || size > INT_MAX) return NULL; - else if (size < 4) - size = 4; + if (size < sizeof(struct dma_block)) + size = sizeof(struct dma_block); size = ALIGN(size, align); allocation = max_t(size_t, size, PAGE_SIZE); @@ -223,7 +251,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, boundary = min(boundary, allocation); - retval = kmalloc(sizeof(*retval), GFP_KERNEL); + retval = kzalloc(sizeof(*retval), GFP_KERNEL); if (!retval) return retval; @@ -236,7 +264,6 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, retval->size = size; retval->boundary = boundary; retval->allocation = allocation; - INIT_LIST_HEAD(&retval->pools); /* @@ -273,21 +300,25 @@ EXPORT_SYMBOL(dma_pool_create); static void pool_initialise_page(struct dma_pool *pool, struct dma_page *page) { - unsigned int offset = 0; - unsigned int next_boundary = pool->boundary; + unsigned int next_boundary = pool->boundary, offset = 0; + struct dma_block *block; pool_init_page(pool, page); - page->in_use = 0; - page->offset = 0; - do { - unsigned int next = offset + pool->size; - if (unlikely((next + pool->size) >= next_boundary)) { - next = next_boundary; + while (offset + pool->size <= pool->allocation) { + if (offset + pool->size > next_boundary) { + offset = next_boundary; next_boundary += pool->boundary; + continue; } - *(int *)(page->vaddr + offset) = next; - offset = next; - } while (offset < pool->allocation); + + block = page->vaddr + offset; + pool_block_push(pool, block, page->dma + offset); + offset += pool->size; + pool->nr_blocks++; + } + + list_add(&page->page_list, &pool->page_list); + pool->nr_pages++; } static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) @@ -305,15 +336,9 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) return NULL; } - pool_initialise_page(pool, page); return page; } -static inline bool is_page_busy(struct dma_page *page) -{ - return page->in_use != 0; -} - /** * dma_pool_destroy - destroys a pool of dma memory blocks. * @pool: dma pool that will be destroyed @@ -325,7 +350,7 @@ static inline bool is_page_busy(struct dma_page *page) void dma_pool_destroy(struct dma_pool *pool) { struct dma_page *page, *tmp; - bool empty = false; + bool empty = false, busy = false; if (unlikely(!pool)) return; @@ -340,13 +365,15 @@ void dma_pool_destroy(struct dma_pool *pool) device_remove_file(pool->dev, &dev_attr_pools); mutex_unlock(&pools_reg_lock); + if (pool->nr_active) { + dev_err(pool->dev, "%s %s busy\n", __func__, pool->name); + busy = true; + } + list_for_each_entry_safe(page, tmp, &pool->page_list, page_list) { - if (!is_page_busy(page)) + if (!busy) dma_free_coherent(pool->dev, pool->allocation, page->vaddr, page->dma); - else - dev_err(pool->dev, "%s %s, %p busy\n", __func__, - pool->name, page->vaddr); list_del(&page->page_list); kfree(page); } @@ -368,58 +395,40 @@ EXPORT_SYMBOL(dma_pool_destroy); void *dma_pool_alloc(struct dma_pool *pool, gfp_t mem_flags, dma_addr_t *handle) { - unsigned long flags; + struct dma_block *block; struct dma_page *page; - unsigned int offset; - void *retval; + unsigned long flags; might_alloc(mem_flags); spin_lock_irqsave(&pool->lock, flags); - list_for_each_entry(page, &pool->page_list, page_list) { - if (page->offset < pool->allocation) - goto ready; - } - - /* pool_alloc_page() might sleep, so temporarily drop &pool->lock */ - spin_unlock_irqrestore(&pool->lock, flags); - - page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); - if (!page) - return NULL; + block = pool_block_pop(pool); + if (!block) { + /* + * pool_alloc_page() might sleep, so temporarily drop + * &pool->lock + */ + spin_unlock_irqrestore(&pool->lock, flags); - spin_lock_irqsave(&pool->lock, flags); + page = pool_alloc_page(pool, mem_flags & (~__GFP_ZERO)); + if (!page) + return NULL; - list_add(&page->page_list, &pool->page_list); - ready: - page->in_use++; - offset = page->offset; - page->offset = *(int *)(page->vaddr + offset); - retval = offset + page->vaddr; - *handle = offset + page->dma; - pool_check_block(pool, retval, offset, mem_flags); + spin_lock_irqsave(&pool->lock, flags); + pool_initialise_page(pool, page); + block = pool_block_pop(pool); + } spin_unlock_irqrestore(&pool->lock, flags); + *handle = block->dma; + pool_check_block(pool, block, mem_flags); if (want_init_on_alloc(mem_flags)) - memset(retval, 0, pool->size); + memset(block, 0, pool->size); - return retval; + return block; } EXPORT_SYMBOL(dma_pool_alloc); -static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) -{ - struct dma_page *page; - - list_for_each_entry(page, &pool->page_list, page_list) { - if (dma < page->dma) - continue; - if ((dma - page->dma) < pool->allocation) - return page; - } - return NULL; -} - /** * dma_pool_free - put block back into dma pool * @pool: the dma pool holding the block @@ -431,31 +440,14 @@ static struct dma_page *pool_find_page(struct dma_pool *pool, dma_addr_t dma) */ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma) { - struct dma_page *page; + struct dma_block *block = vaddr; unsigned long flags; spin_lock_irqsave(&pool->lock, flags); - page = pool_find_page(pool, dma); - if (!page) { - spin_unlock_irqrestore(&pool->lock, flags); - dev_err(pool->dev, "%s %s, %p/%pad (bad dma)\n", - __func__, pool->name, vaddr, &dma); - return; + if (!pool_block_err(pool, vaddr, dma)) { + pool_block_push(pool, block, dma); + pool->nr_active--; } - - if (pool_page_err(pool, page, vaddr, dma)) { - spin_unlock_irqrestore(&pool->lock, flags); - return; - } - - page->in_use--; - *(int *)vaddr = page->offset; - page->offset = vaddr - page->vaddr; - /* - * Resist a temptation to do - * if (!is_page_busy(page)) pool_free_page(pool, page); - * Better have a few empty pages hang around. - */ spin_unlock_irqrestore(&pool->lock, flags); } EXPORT_SYMBOL(dma_pool_free); From ea3bbdc313dc0b4e7ce6730788de643c82fae6ee Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Thu, 26 Jan 2023 13:51:25 -0800 Subject: [PATCH 29/80] dmapool: create/destroy cleanup Set the 'empty' bool directly from the result of the function that determines its value instead of adding additional logic. Link: https://lkml.kernel.org/r/20230126215125.4069751-13-kbusch@meta.com Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig Cc: Matthew Wilcox Cc: Tony Battersby Signed-off-by: Andrew Morton --- mm/dmapool.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/mm/dmapool.c b/mm/dmapool.c index bb8893b4f4b96..1920890ff8d3d 100644 --- a/mm/dmapool.c +++ b/mm/dmapool.c @@ -226,7 +226,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, { struct dma_pool *retval; size_t allocation; - bool empty = false; + bool empty; if (!dev) return NULL; @@ -276,8 +276,7 @@ struct dma_pool *dma_pool_create(const char *name, struct device *dev, */ mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); - if (list_empty(&dev->dma_pools)) - empty = true; + empty = list_empty(&dev->dma_pools); list_add(&retval->pools, &dev->dma_pools); mutex_unlock(&pools_lock); if (empty) { @@ -350,7 +349,7 @@ static struct dma_page *pool_alloc_page(struct dma_pool *pool, gfp_t mem_flags) void dma_pool_destroy(struct dma_pool *pool) { struct dma_page *page, *tmp; - bool empty = false, busy = false; + bool empty, busy = false; if (unlikely(!pool)) return; @@ -358,8 +357,7 @@ void dma_pool_destroy(struct dma_pool *pool) mutex_lock(&pools_reg_lock); mutex_lock(&pools_lock); list_del(&pool->pools); - if (list_empty(&pool->dev->dma_pools)) - empty = true; + empty = list_empty(&pool->dev->dma_pools); mutex_unlock(&pools_lock); if (empty) device_remove_file(pool->dev, &dev_attr_pools); From aaee54ef50a8e94c810b3cdbc32f29cb668ef33a Mon Sep 17 00:00:00 2001 From: Alexander Halbuer Date: Wed, 1 Feb 2023 17:25:49 +0100 Subject: [PATCH 30/80] mm: reduce lock contention of pcp buffer refill rmqueue_bulk() batches the allocation of multiple elements to refill the per-CPU buffers into a single hold of the zone lock. Each element is allocated and checked using check_pcp_refill(). The check touches every related struct page which is especially expensive for higher order allocations (huge pages). This patch reduces the time holding the lock by moving the check out of the critical section similar to rmqueue_buddy() which allocates a single element. Measurements of parallel allocation-heavy workloads show a reduction of the average huge page allocation latency of 50 percent for two cores and nearly 90 percent for 24 cores. Link: https://lkml.kernel.org/r/20230201162549.68384-1-halbuer@sra.uni-hannover.de Signed-off-by: Alexander Halbuer Cc: Mel Gorman Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/page_alloc.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6eb9c58fcd997..6721c0ba12f8b 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3137,6 +3137,8 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, { unsigned long flags; int i, allocated = 0; + struct list_head *prev_tail = list->prev; + struct page *pos, *n; spin_lock_irqsave(&zone->lock, flags); for (i = 0; i < count; ++i) { @@ -3145,9 +3147,6 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, if (unlikely(page == NULL)) break; - if (unlikely(check_pcp_refill(page, order))) - continue; - /* * Split buddy pages returned by expand() are received here in * physical page order. The page is added to the tail of @@ -3159,7 +3158,6 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, * pages are ordered properly. */ list_add_tail(&page->pcp_list, list); - allocated++; if (is_migrate_cma(get_pcppage_migratetype(page))) __mod_zone_page_state(zone, NR_FREE_CMA_PAGES, -(1 << order)); @@ -3173,6 +3171,22 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order, */ __mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order)); spin_unlock_irqrestore(&zone->lock, flags); + + /* + * Pages are appended to the pcp list without checking to reduce the + * time holding the zone lock. Checking the appended pages happens right + * after the critical section while still holding the pcp lock. + */ + pos = list_first_entry(prev_tail, struct page, pcp_list); + list_for_each_entry_safe_from(pos, n, list, pcp_list) { + if (unlikely(check_pcp_refill(pos, order))) { + list_del(&pos->pcp_list); + continue; + } + + allocated++; + } + return allocated; } From 3ac8e31936124f89c68da496775a38f258b7ea77 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:49 +0100 Subject: [PATCH 31/80] lib/stackdepot: put functions in logical order Patch series "lib/stackdepot: fixes and clean-ups", v2. A set of fixes, comments, and clean-ups I came up with while reading the stack depot code. This patch (of 18): Put stack depot functions' declarations and definitions in a more logical order: 1. Functions that save stack traces into stack depot. 2. Functions that fetch and print stack traces. 3. stack_depot_get_extra_bits that operates on stack depot handles and does not interact with the stack depot storage. No functional changes. Link: https://lkml.kernel.org/r/cover.1676063693.git.andreyknvl@google.com Link: https://lkml.kernel.org/r/daca1319b665d826b94c596b992a8d8117846147.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Cc: Evgenii Stepanov Cc: Marco Elver Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 15 +- lib/stackdepot.c | 314 ++++++++++++++++++------------------- 2 files changed, 165 insertions(+), 164 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 9ca7798d7a318..1296a6eeaec0a 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -14,17 +14,13 @@ #include typedef u32 depot_stack_handle_t; + /* * Number of bits in the handle that stack depot doesn't use. Users may store * information in them. */ #define STACK_DEPOT_EXTRA_BITS 5 -depot_stack_handle_t __stack_depot_save(unsigned long *entries, - unsigned int nr_entries, - unsigned int extra_bits, - gfp_t gfp_flags, bool can_alloc); - /* * Every user of stack depot has to call stack_depot_init() during its own init * when it's decided that it will be calling stack_depot_save() later. This is @@ -59,17 +55,22 @@ static inline void stack_depot_want_early_init(void) { } static inline int stack_depot_early_init(void) { return 0; } #endif +depot_stack_handle_t __stack_depot_save(unsigned long *entries, + unsigned int nr_entries, + unsigned int extra_bits, + gfp_t gfp_flags, bool can_alloc); + depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags); unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries); -unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); +void stack_depot_print(depot_stack_handle_t stack); int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces); -void stack_depot_print(depot_stack_handle_t stack); +unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); #endif diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 79e894cf84064..4bfaf3bce619c 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -79,84 +79,6 @@ static int next_slab_inited; static size_t depot_offset; static DEFINE_RAW_SPINLOCK(depot_lock); -unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) -{ - union handle_parts parts = { .handle = handle }; - - return parts.extra; -} -EXPORT_SYMBOL(stack_depot_get_extra_bits); - -static bool init_stack_slab(void **prealloc) -{ - if (!*prealloc) - return false; - /* - * This smp_load_acquire() pairs with smp_store_release() to - * |next_slab_inited| below and in depot_alloc_stack(). - */ - if (smp_load_acquire(&next_slab_inited)) - return true; - if (stack_slabs[depot_index] == NULL) { - stack_slabs[depot_index] = *prealloc; - *prealloc = NULL; - } else { - /* If this is the last depot slab, do not touch the next one. */ - if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) { - stack_slabs[depot_index + 1] = *prealloc; - *prealloc = NULL; - } - /* - * This smp_store_release pairs with smp_load_acquire() from - * |next_slab_inited| above and in stack_depot_save(). - */ - smp_store_release(&next_slab_inited, 1); - } - return true; -} - -/* Allocation of a new stack in raw storage */ -static struct stack_record * -depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) -{ - struct stack_record *stack; - size_t required_size = struct_size(stack, entries, size); - - required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN); - - if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) { - if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) { - WARN_ONCE(1, "Stack depot reached limit capacity"); - return NULL; - } - depot_index++; - depot_offset = 0; - /* - * smp_store_release() here pairs with smp_load_acquire() from - * |next_slab_inited| in stack_depot_save() and - * init_stack_slab(). - */ - if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) - smp_store_release(&next_slab_inited, 0); - } - init_stack_slab(prealloc); - if (stack_slabs[depot_index] == NULL) - return NULL; - - stack = stack_slabs[depot_index] + depot_offset; - - stack->hash = hash; - stack->size = size; - stack->handle.slabindex = depot_index; - stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN; - stack->handle.valid = 1; - stack->handle.extra = 0; - memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); - depot_offset += required_size; - - return stack; -} - /* one hash table bucket entry per 16kB of memory */ #define STACK_HASH_SCALE 14 /* limited between 4k and 1M buckets */ @@ -270,6 +192,76 @@ int stack_depot_init(void) } EXPORT_SYMBOL_GPL(stack_depot_init); +static bool init_stack_slab(void **prealloc) +{ + if (!*prealloc) + return false; + /* + * This smp_load_acquire() pairs with smp_store_release() to + * |next_slab_inited| below and in depot_alloc_stack(). + */ + if (smp_load_acquire(&next_slab_inited)) + return true; + if (stack_slabs[depot_index] == NULL) { + stack_slabs[depot_index] = *prealloc; + *prealloc = NULL; + } else { + /* If this is the last depot slab, do not touch the next one. */ + if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) { + stack_slabs[depot_index + 1] = *prealloc; + *prealloc = NULL; + } + /* + * This smp_store_release pairs with smp_load_acquire() from + * |next_slab_inited| above and in stack_depot_save(). + */ + smp_store_release(&next_slab_inited, 1); + } + return true; +} + +/* Allocation of a new stack in raw storage */ +static struct stack_record * +depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) +{ + struct stack_record *stack; + size_t required_size = struct_size(stack, entries, size); + + required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN); + + if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) { + if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) { + WARN_ONCE(1, "Stack depot reached limit capacity"); + return NULL; + } + depot_index++; + depot_offset = 0; + /* + * smp_store_release() here pairs with smp_load_acquire() from + * |next_slab_inited| in stack_depot_save() and + * init_stack_slab(). + */ + if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) + smp_store_release(&next_slab_inited, 0); + } + init_stack_slab(prealloc); + if (stack_slabs[depot_index] == NULL) + return NULL; + + stack = stack_slabs[depot_index] + depot_offset; + + stack->hash = hash; + stack->size = size; + stack->handle.slabindex = depot_index; + stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN; + stack->handle.valid = 1; + stack->handle.extra = 0; + memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); + depot_offset += required_size; + + return stack; +} + /* Calculate hash for a stack */ static inline u32 hash_stack(unsigned long *entries, unsigned int size) { @@ -309,85 +301,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, return NULL; } -/** - * stack_depot_snprint - print stack entries from a depot into a buffer - * - * @handle: Stack depot handle which was returned from - * stack_depot_save(). - * @buf: Pointer to the print buffer - * - * @size: Size of the print buffer - * - * @spaces: Number of leading spaces to print - * - * Return: Number of bytes printed. - */ -int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, - int spaces) -{ - unsigned long *entries; - unsigned int nr_entries; - - nr_entries = stack_depot_fetch(handle, &entries); - return nr_entries ? stack_trace_snprint(buf, size, entries, nr_entries, - spaces) : 0; -} -EXPORT_SYMBOL_GPL(stack_depot_snprint); - -/** - * stack_depot_print - print stack entries from a depot - * - * @stack: Stack depot handle which was returned from - * stack_depot_save(). - * - */ -void stack_depot_print(depot_stack_handle_t stack) -{ - unsigned long *entries; - unsigned int nr_entries; - - nr_entries = stack_depot_fetch(stack, &entries); - if (nr_entries > 0) - stack_trace_print(entries, nr_entries, 0); -} -EXPORT_SYMBOL_GPL(stack_depot_print); - -/** - * stack_depot_fetch - Fetch stack entries from a depot - * - * @handle: Stack depot handle which was returned from - * stack_depot_save(). - * @entries: Pointer to store the entries address - * - * Return: The number of trace entries for this depot. - */ -unsigned int stack_depot_fetch(depot_stack_handle_t handle, - unsigned long **entries) -{ - union handle_parts parts = { .handle = handle }; - void *slab; - size_t offset = parts.offset << STACK_ALLOC_ALIGN; - struct stack_record *stack; - - *entries = NULL; - if (!handle) - return 0; - - if (parts.slabindex > depot_index) { - WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n", - parts.slabindex, depot_index, handle); - return 0; - } - slab = stack_slabs[parts.slabindex]; - if (!slab) - return 0; - stack = slab + offset; - - *entries = stack->entries; - return stack->size; -} -EXPORT_SYMBOL_GPL(stack_depot_fetch); - /** * __stack_depot_save - Save a stack trace from an array * @@ -533,3 +446,90 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, return __stack_depot_save(entries, nr_entries, 0, alloc_flags, true); } EXPORT_SYMBOL_GPL(stack_depot_save); + +/** + * stack_depot_fetch - Fetch stack entries from a depot + * + * @handle: Stack depot handle which was returned from + * stack_depot_save(). + * @entries: Pointer to store the entries address + * + * Return: The number of trace entries for this depot. + */ +unsigned int stack_depot_fetch(depot_stack_handle_t handle, + unsigned long **entries) +{ + union handle_parts parts = { .handle = handle }; + void *slab; + size_t offset = parts.offset << STACK_ALLOC_ALIGN; + struct stack_record *stack; + + *entries = NULL; + if (!handle) + return 0; + + if (parts.slabindex > depot_index) { + WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n", + parts.slabindex, depot_index, handle); + return 0; + } + slab = stack_slabs[parts.slabindex]; + if (!slab) + return 0; + stack = slab + offset; + + *entries = stack->entries; + return stack->size; +} +EXPORT_SYMBOL_GPL(stack_depot_fetch); + +/** + * stack_depot_print - print stack entries from a depot + * + * @stack: Stack depot handle which was returned from + * stack_depot_save(). + * + */ +void stack_depot_print(depot_stack_handle_t stack) +{ + unsigned long *entries; + unsigned int nr_entries; + + nr_entries = stack_depot_fetch(stack, &entries); + if (nr_entries > 0) + stack_trace_print(entries, nr_entries, 0); +} +EXPORT_SYMBOL_GPL(stack_depot_print); + +/** + * stack_depot_snprint - print stack entries from a depot into a buffer + * + * @handle: Stack depot handle which was returned from + * stack_depot_save(). + * @buf: Pointer to the print buffer + * + * @size: Size of the print buffer + * + * @spaces: Number of leading spaces to print + * + * Return: Number of bytes printed. + */ +int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, + int spaces) +{ + unsigned long *entries; + unsigned int nr_entries; + + nr_entries = stack_depot_fetch(handle, &entries); + return nr_entries ? stack_trace_snprint(buf, size, entries, nr_entries, + spaces) : 0; +} +EXPORT_SYMBOL_GPL(stack_depot_snprint); + +unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) +{ + union handle_parts parts = { .handle = handle }; + + return parts.extra; +} +EXPORT_SYMBOL(stack_depot_get_extra_bits); From 9038f07d54f420883d52a3838ba18b1f5291c53f Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:50 +0100 Subject: [PATCH 32/80] lib/stackdepot: use pr_fmt to define message format Use pr_fmt to define the format for printing stack depot messages instead of duplicating the "Stack Depot" prefix in each message. Link: https://lkml.kernel.org/r/3d09db0171a0e92ff3eb0ee74de74558bc9b56c4.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 4bfaf3bce619c..83787e46a3ab3 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -19,6 +19,8 @@ * Based on code by Dmitry Chernenkov. */ +#define pr_fmt(fmt) "stackdepot: " fmt + #include #include #include @@ -98,7 +100,7 @@ static int __init is_stack_depot_disabled(char *str) ret = kstrtobool(str, &stack_depot_disable); if (!ret && stack_depot_disable) { - pr_info("Stack Depot is disabled\n"); + pr_info("disabled\n"); stack_table = NULL; } return 0; @@ -142,7 +144,7 @@ int __init stack_depot_early_init(void) 1UL << STACK_HASH_ORDER_MAX); if (!stack_table) { - pr_err("Stack Depot hash table allocation failed, disabling\n"); + pr_err("hash table allocation failed, disabling\n"); stack_depot_disable = true; return -ENOMEM; } @@ -177,11 +179,11 @@ int stack_depot_init(void) if (entries > 1UL << STACK_HASH_ORDER_MAX) entries = 1UL << STACK_HASH_ORDER_MAX; - pr_info("Stack Depot allocating hash table of %lu entries with kvcalloc\n", + pr_info("allocating hash table of %lu entries with kvcalloc\n", entries); stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); if (!stack_table) { - pr_err("Stack Depot hash table allocation failed, disabling\n"); + pr_err("hash table allocation failed, disabling\n"); stack_depot_disable = true; ret = -ENOMEM; } From e245b40b584a7dd7ce5b91cc0b3709f2fc18b5e9 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:51 +0100 Subject: [PATCH 33/80] lib/stackdepot, mm: rename stack_depot_want_early_init Rename stack_depot_want_early_init to stack_depot_request_early_init. The old name is confusing, as it hints at returning some kind of intention of stack depot. The new name reflects that this function requests an action from stack depot instead. No functional changes. Link: https://lkml.kernel.org/r/359f31bf67429a06e630b4395816a967214ef753.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Acked-by: Vlastimil Babka Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 14 +++++++------- lib/stackdepot.c | 10 +++++----- mm/page_owner.c | 2 +- mm/slub.c | 4 ++-- 4 files changed, 15 insertions(+), 15 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 1296a6eeaec0a..c4e3abc16b16a 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -31,26 +31,26 @@ typedef u32 depot_stack_handle_t; * enabled as part of mm_init(), for subsystems where it's known at compile time * that stack depot will be used. * - * Another alternative is to call stack_depot_want_early_init(), when the + * Another alternative is to call stack_depot_request_early_init(), when the * decision to use stack depot is taken e.g. when evaluating kernel boot * parameters, which precedes the enablement point in mm_init(). * - * stack_depot_init() and stack_depot_want_early_init() can be called regardless - * of CONFIG_STACKDEPOT and are no-op when disabled. The actual save/fetch/print - * functions should only be called from code that makes sure CONFIG_STACKDEPOT - * is enabled. + * stack_depot_init() and stack_depot_request_early_init() can be called + * regardless of CONFIG_STACKDEPOT and are no-op when disabled. The actual + * save/fetch/print functions should only be called from code that makes sure + * CONFIG_STACKDEPOT is enabled. */ #ifdef CONFIG_STACKDEPOT int stack_depot_init(void); -void __init stack_depot_want_early_init(void); +void __init stack_depot_request_early_init(void); /* This is supposed to be called only from mm_init() */ int __init stack_depot_early_init(void); #else static inline int stack_depot_init(void) { return 0; } -static inline void stack_depot_want_early_init(void) { } +static inline void stack_depot_request_early_init(void) { } static inline int stack_depot_early_init(void) { return 0; } #endif diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 83787e46a3ab3..136706efe339d 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -71,7 +71,7 @@ struct stack_record { unsigned long entries[]; /* Variable-sized array of entries. */ }; -static bool __stack_depot_want_early_init __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT); +static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT); static bool __stack_depot_early_init_passed __initdata; static void *stack_slabs[STACK_ALLOC_MAX_SLABS]; @@ -107,12 +107,12 @@ static int __init is_stack_depot_disabled(char *str) } early_param("stack_depot_disable", is_stack_depot_disabled); -void __init stack_depot_want_early_init(void) +void __init stack_depot_request_early_init(void) { - /* Too late to request early init now */ + /* Too late to request early init now. */ WARN_ON(__stack_depot_early_init_passed); - __stack_depot_want_early_init = true; + __stack_depot_early_init_requested = true; } int __init stack_depot_early_init(void) @@ -128,7 +128,7 @@ int __init stack_depot_early_init(void) if (kasan_enabled() && !stack_hash_order) stack_hash_order = STACK_HASH_ORDER_MAX; - if (!__stack_depot_want_early_init || stack_depot_disable) + if (!__stack_depot_early_init_requested || stack_depot_disable) return 0; if (stack_hash_order) diff --git a/mm/page_owner.c b/mm/page_owner.c index 80dc8f4050faa..220cdeddc2950 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -48,7 +48,7 @@ static int __init early_page_owner_param(char *buf) int ret = kstrtobool(buf, &page_owner_enabled); if (page_owner_enabled) - stack_depot_want_early_init(); + stack_depot_request_early_init(); return ret; } diff --git a/mm/slub.c b/mm/slub.c index 67020074ecb40..f8dba33e4d15f 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1592,7 +1592,7 @@ static int __init setup_slub_debug(char *str) } else { slab_list_specified = true; if (flags & SLAB_STORE_USER) - stack_depot_want_early_init(); + stack_depot_request_early_init(); } } @@ -1611,7 +1611,7 @@ static int __init setup_slub_debug(char *str) out: slub_debug = global_flags; if (slub_debug & SLAB_STORE_USER) - stack_depot_want_early_init(); + stack_depot_request_early_init(); if (slub_debug != 0 || slub_debug_string) static_branch_enable(&slub_debug_enabled); else From 9eae7c6b4b7396b2de91c392f35e2b87102bb1bd Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Fri, 10 Feb 2023 15:13:49 -0800 Subject: [PATCH 34/80] lib-stackdepot-mm-rename-stack_depot_want_early_init-fix update mm/kmemleak.c Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/kmemleak.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/kmemleak.c b/mm/kmemleak.c index d9b242cfdb1c9..a2d34226e3c8c 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -2071,7 +2071,7 @@ static int __init kmemleak_boot_config(char *str) kmemleak_disable(); else if (strcmp(str, "on") == 0) { kmemleak_skip_disable = 1; - stack_depot_want_early_init(); + stack_depot_request_early_init(); } else return -EINVAL; From e76f34f031afb28b8a5f713393d272e4a2745f41 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:52 +0100 Subject: [PATCH 35/80] lib/stackdepot: rename stack_depot_disable Rename stack_depot_disable to stack_depot_disabled to make its name look similar to the names of other stack depot flags. Also put stack_depot_disabled's definition together with the other flags. Also rename is_stack_depot_disabled to disable_stack_depot: this name looks more conventional for a function that processes a boot parameter. No functional changes. Link: https://lkml.kernel.org/r/d78a07d222e689926e5ead229e4a2e3d87dc9aa7.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 136706efe339d..202e07c4f02d6 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -71,6 +71,7 @@ struct stack_record { unsigned long entries[]; /* Variable-sized array of entries. */ }; +static bool stack_depot_disabled; static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT); static bool __stack_depot_early_init_passed __initdata; @@ -91,21 +92,20 @@ static DEFINE_RAW_SPINLOCK(depot_lock); static unsigned int stack_hash_order; static unsigned int stack_hash_mask; -static bool stack_depot_disable; static struct stack_record **stack_table; -static int __init is_stack_depot_disabled(char *str) +static int __init disable_stack_depot(char *str) { int ret; - ret = kstrtobool(str, &stack_depot_disable); - if (!ret && stack_depot_disable) { + ret = kstrtobool(str, &stack_depot_disabled); + if (!ret && stack_depot_disabled) { pr_info("disabled\n"); stack_table = NULL; } return 0; } -early_param("stack_depot_disable", is_stack_depot_disabled); +early_param("stack_depot_disable", disable_stack_depot); void __init stack_depot_request_early_init(void) { @@ -128,7 +128,7 @@ int __init stack_depot_early_init(void) if (kasan_enabled() && !stack_hash_order) stack_hash_order = STACK_HASH_ORDER_MAX; - if (!__stack_depot_early_init_requested || stack_depot_disable) + if (!__stack_depot_early_init_requested || stack_depot_disabled) return 0; if (stack_hash_order) @@ -145,7 +145,7 @@ int __init stack_depot_early_init(void) if (!stack_table) { pr_err("hash table allocation failed, disabling\n"); - stack_depot_disable = true; + stack_depot_disabled = true; return -ENOMEM; } @@ -158,7 +158,7 @@ int stack_depot_init(void) int ret = 0; mutex_lock(&stack_depot_init_mutex); - if (!stack_depot_disable && !stack_table) { + if (!stack_depot_disabled && !stack_table) { unsigned long entries; int scale = STACK_HASH_SCALE; @@ -184,7 +184,7 @@ int stack_depot_init(void) stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); if (!stack_table) { pr_err("hash table allocation failed, disabling\n"); - stack_depot_disable = true; + stack_depot_disabled = true; ret = -ENOMEM; } stack_hash_mask = entries - 1; @@ -353,7 +353,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, */ nr_entries = filter_irq_stacks(entries, nr_entries); - if (unlikely(nr_entries == 0) || stack_depot_disable) + if (unlikely(nr_entries == 0) || stack_depot_disabled) goto fast_exit; hash = hash_stack(entries, nr_entries); From ca77610d11b4b8b67c1781bbfd5401a3e1dc4036 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:53 +0100 Subject: [PATCH 36/80] lib/stackdepot: annotate init and early init functions Add comments to stack_depot_early_init and stack_depot_init to explain certain parts of their implementation. Also add a pr_info message to stack_depot_early_init similar to the one in stack_depot_init. Also move the scale variable in stack_depot_init to the scope where it is being used. Link: https://lkml.kernel.org/r/d17fbfbd4d73f38686c5e3d4824a6d62047213a1.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 202e07c4f02d6..9fab711e48265 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -115,24 +115,34 @@ void __init stack_depot_request_early_init(void) __stack_depot_early_init_requested = true; } +/* Allocates a hash table via memblock. Can only be used during early boot. */ int __init stack_depot_early_init(void) { unsigned long entries = 0; - /* This is supposed to be called only once, from mm_init() */ + /* This function must be called only once, from mm_init(). */ if (WARN_ON(__stack_depot_early_init_passed)) return 0; - __stack_depot_early_init_passed = true; + /* + * If KASAN is enabled, use the maximum order: KASAN is frequently used + * in fuzzing scenarios, which leads to a large number of different + * stack traces being stored in stack depot. + */ if (kasan_enabled() && !stack_hash_order) stack_hash_order = STACK_HASH_ORDER_MAX; if (!__stack_depot_early_init_requested || stack_depot_disabled) return 0; + /* + * If stack_hash_order is not set, leave entries as 0 to rely on the + * automatic calculations performed by alloc_large_system_hash. + */ if (stack_hash_order) - entries = 1UL << stack_hash_order; + entries = 1UL << stack_hash_order; + pr_info("allocating hash table via alloc_large_system_hash\n"); stack_table = alloc_large_system_hash("stackdepot", sizeof(struct stack_record *), entries, @@ -142,7 +152,6 @@ int __init stack_depot_early_init(void) &stack_hash_mask, 1UL << STACK_HASH_ORDER_MIN, 1UL << STACK_HASH_ORDER_MAX); - if (!stack_table) { pr_err("hash table allocation failed, disabling\n"); stack_depot_disabled = true; @@ -152,6 +161,7 @@ int __init stack_depot_early_init(void) return 0; } +/* Allocates a hash table via kvcalloc. Can be used after boot. */ int stack_depot_init(void) { static DEFINE_MUTEX(stack_depot_init_mutex); @@ -160,11 +170,16 @@ int stack_depot_init(void) mutex_lock(&stack_depot_init_mutex); if (!stack_depot_disabled && !stack_table) { unsigned long entries; - int scale = STACK_HASH_SCALE; + /* + * Similarly to stack_depot_early_init, use stack_hash_order + * if assigned, and rely on automatic scaling otherwise. + */ if (stack_hash_order) { entries = 1UL << stack_hash_order; } else { + int scale = STACK_HASH_SCALE; + entries = nr_free_buffer_pages(); entries = roundup_pow_of_two(entries); @@ -179,7 +194,7 @@ int stack_depot_init(void) if (entries > 1UL << STACK_HASH_ORDER_MAX) entries = 1UL << STACK_HASH_ORDER_MAX; - pr_info("allocating hash table of %lu entries with kvcalloc\n", + pr_info("allocating hash table of %lu entries via kvcalloc\n", entries); stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); if (!stack_table) { From 1cd7891dee3c5c798c769704dc6dd575048a93d4 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:54 +0100 Subject: [PATCH 37/80] lib/stackdepot: lower the indentation in stack_depot_init stack_depot_init does most things inside an if check. Move them out and use a goto statement instead. No functional changes. Link: https://lkml.kernel.org/r/8e382f1f0c352e4b2ad47326fec7782af961fe8e.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 70 +++++++++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 33 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 9fab711e48265..3c713f70b0a36 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -165,46 +165,50 @@ int __init stack_depot_early_init(void) int stack_depot_init(void) { static DEFINE_MUTEX(stack_depot_init_mutex); + unsigned long entries; int ret = 0; mutex_lock(&stack_depot_init_mutex); - if (!stack_depot_disabled && !stack_table) { - unsigned long entries; - /* - * Similarly to stack_depot_early_init, use stack_hash_order - * if assigned, and rely on automatic scaling otherwise. - */ - if (stack_hash_order) { - entries = 1UL << stack_hash_order; - } else { - int scale = STACK_HASH_SCALE; - - entries = nr_free_buffer_pages(); - entries = roundup_pow_of_two(entries); - - if (scale > PAGE_SHIFT) - entries >>= (scale - PAGE_SHIFT); - else - entries <<= (PAGE_SHIFT - scale); - } + if (stack_depot_disabled || stack_table) + goto out_unlock; - if (entries < 1UL << STACK_HASH_ORDER_MIN) - entries = 1UL << STACK_HASH_ORDER_MIN; - if (entries > 1UL << STACK_HASH_ORDER_MAX) - entries = 1UL << STACK_HASH_ORDER_MAX; - - pr_info("allocating hash table of %lu entries via kvcalloc\n", - entries); - stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); - if (!stack_table) { - pr_err("hash table allocation failed, disabling\n"); - stack_depot_disabled = true; - ret = -ENOMEM; - } - stack_hash_mask = entries - 1; + /* + * Similarly to stack_depot_early_init, use stack_hash_order + * if assigned, and rely on automatic scaling otherwise. + */ + if (stack_hash_order) { + entries = 1UL << stack_hash_order; + } else { + int scale = STACK_HASH_SCALE; + + entries = nr_free_buffer_pages(); + entries = roundup_pow_of_two(entries); + + if (scale > PAGE_SHIFT) + entries >>= (scale - PAGE_SHIFT); + else + entries <<= (PAGE_SHIFT - scale); } + + if (entries < 1UL << STACK_HASH_ORDER_MIN) + entries = 1UL << STACK_HASH_ORDER_MIN; + if (entries > 1UL << STACK_HASH_ORDER_MAX) + entries = 1UL << STACK_HASH_ORDER_MAX; + + pr_info("allocating hash table of %lu entries via kvcalloc\n", entries); + stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); + if (!stack_table) { + pr_err("hash table allocation failed, disabling\n"); + stack_depot_disabled = true; + ret = -ENOMEM; + goto out_unlock; + } + stack_hash_mask = entries - 1; + +out_unlock: mutex_unlock(&stack_depot_init_mutex); + return ret; } EXPORT_SYMBOL_GPL(stack_depot_init); From 7d9275151ae564564628436418eef17d78441fd2 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:55 +0100 Subject: [PATCH 38/80] lib/stackdepot: reorder and annotate global variables Group stack depot global variables by their purpose: 1. Hash table-related variables, 2. Slab-related variables, and add comments. Also clean up comments for hash table-related constants. Link: https://lkml.kernel.org/r/5606a6c70659065a25bee59cd10e57fc60bb4110.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 3c713f70b0a36..de1afe3fb24d0 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -75,24 +75,31 @@ static bool stack_depot_disabled; static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT); static bool __stack_depot_early_init_passed __initdata; -static void *stack_slabs[STACK_ALLOC_MAX_SLABS]; - -static int depot_index; -static int next_slab_inited; -static size_t depot_offset; -static DEFINE_RAW_SPINLOCK(depot_lock); - -/* one hash table bucket entry per 16kB of memory */ +/* Use one hash table bucket per 16 KB of memory. */ #define STACK_HASH_SCALE 14 -/* limited between 4k and 1M buckets */ +/* Limit the number of buckets between 4K and 1M. */ #define STACK_HASH_ORDER_MIN 12 #define STACK_HASH_ORDER_MAX 20 +/* Initial seed for jhash2. */ #define STACK_HASH_SEED 0x9747b28c +/* Hash table of pointers to stored stack traces. */ +static struct stack_record **stack_table; +/* Fixed order of the number of table buckets. Used when KASAN is enabled. */ static unsigned int stack_hash_order; +/* Hash mask for indexing the table. */ static unsigned int stack_hash_mask; -static struct stack_record **stack_table; +/* Array of memory regions that store stack traces. */ +static void *stack_slabs[STACK_ALLOC_MAX_SLABS]; +/* Currently used slab in stack_slabs. */ +static int depot_index; +/* Offset to the unused space in the currently used slab. */ +static size_t depot_offset; +/* Lock that protects the variables above. */ +static DEFINE_RAW_SPINLOCK(depot_lock); +/* Whether the next slab is initialized. */ +static int next_slab_inited; static int __init disable_stack_depot(char *str) { From 0c7ae6175c852770b507a51505e93e68a28c5128 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:56 +0100 Subject: [PATCH 39/80] lib/stackdepot: rename hash table constants and variables Give more meaningful names to hash table-related constants and variables: 1. Rename STACK_HASH_SCALE to STACK_HASH_TABLE_SCALE to point out that it is related to scaling the hash table. 2. Rename STACK_HASH_ORDER_MIN/MAX to STACK_BUCKET_NUMBER_ORDER_MIN/MAX to point out that it is related to the number of hash table buckets. 3. Rename stack_hash_order to stack_bucket_number_order for the same reason as #2. No functional changes. Link: https://lkml.kernel.org/r/f166dd6f3cb2378aea78600714393dd568c33ee9.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index de1afe3fb24d0..d1ab53197353e 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -76,17 +76,17 @@ static bool __stack_depot_early_init_requested __initdata = IS_ENABLED(CONFIG_ST static bool __stack_depot_early_init_passed __initdata; /* Use one hash table bucket per 16 KB of memory. */ -#define STACK_HASH_SCALE 14 +#define STACK_HASH_TABLE_SCALE 14 /* Limit the number of buckets between 4K and 1M. */ -#define STACK_HASH_ORDER_MIN 12 -#define STACK_HASH_ORDER_MAX 20 +#define STACK_BUCKET_NUMBER_ORDER_MIN 12 +#define STACK_BUCKET_NUMBER_ORDER_MAX 20 /* Initial seed for jhash2. */ #define STACK_HASH_SEED 0x9747b28c /* Hash table of pointers to stored stack traces. */ static struct stack_record **stack_table; /* Fixed order of the number of table buckets. Used when KASAN is enabled. */ -static unsigned int stack_hash_order; +static unsigned int stack_bucket_number_order; /* Hash mask for indexing the table. */ static unsigned int stack_hash_mask; @@ -137,28 +137,28 @@ int __init stack_depot_early_init(void) * in fuzzing scenarios, which leads to a large number of different * stack traces being stored in stack depot. */ - if (kasan_enabled() && !stack_hash_order) - stack_hash_order = STACK_HASH_ORDER_MAX; + if (kasan_enabled() && !stack_bucket_number_order) + stack_bucket_number_order = STACK_BUCKET_NUMBER_ORDER_MAX; if (!__stack_depot_early_init_requested || stack_depot_disabled) return 0; /* - * If stack_hash_order is not set, leave entries as 0 to rely on the - * automatic calculations performed by alloc_large_system_hash. + * If stack_bucket_number_order is not set, leave entries as 0 to rely + * on the automatic calculations performed by alloc_large_system_hash. */ - if (stack_hash_order) - entries = 1UL << stack_hash_order; + if (stack_bucket_number_order) + entries = 1UL << stack_bucket_number_order; pr_info("allocating hash table via alloc_large_system_hash\n"); stack_table = alloc_large_system_hash("stackdepot", sizeof(struct stack_record *), entries, - STACK_HASH_SCALE, + STACK_HASH_TABLE_SCALE, HASH_EARLY | HASH_ZERO, NULL, &stack_hash_mask, - 1UL << STACK_HASH_ORDER_MIN, - 1UL << STACK_HASH_ORDER_MAX); + 1UL << STACK_BUCKET_NUMBER_ORDER_MIN, + 1UL << STACK_BUCKET_NUMBER_ORDER_MAX); if (!stack_table) { pr_err("hash table allocation failed, disabling\n"); stack_depot_disabled = true; @@ -181,13 +181,13 @@ int stack_depot_init(void) goto out_unlock; /* - * Similarly to stack_depot_early_init, use stack_hash_order + * Similarly to stack_depot_early_init, use stack_bucket_number_order * if assigned, and rely on automatic scaling otherwise. */ - if (stack_hash_order) { - entries = 1UL << stack_hash_order; + if (stack_bucket_number_order) { + entries = 1UL << stack_bucket_number_order; } else { - int scale = STACK_HASH_SCALE; + int scale = STACK_HASH_TABLE_SCALE; entries = nr_free_buffer_pages(); entries = roundup_pow_of_two(entries); @@ -198,10 +198,10 @@ int stack_depot_init(void) entries <<= (PAGE_SHIFT - scale); } - if (entries < 1UL << STACK_HASH_ORDER_MIN) - entries = 1UL << STACK_HASH_ORDER_MIN; - if (entries > 1UL << STACK_HASH_ORDER_MAX) - entries = 1UL << STACK_HASH_ORDER_MAX; + if (entries < 1UL << STACK_BUCKET_NUMBER_ORDER_MIN) + entries = 1UL << STACK_BUCKET_NUMBER_ORDER_MIN; + if (entries > 1UL << STACK_BUCKET_NUMBER_ORDER_MAX) + entries = 1UL << STACK_BUCKET_NUMBER_ORDER_MAX; pr_info("allocating hash table of %lu entries via kvcalloc\n", entries); stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL); From 84821f10a2f20b7bb564f40efba24a9d152b7737 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:57 +0100 Subject: [PATCH 40/80] lib/stackdepot: rename slab to pool Use "pool" instead of "slab" for naming memory regions stack depot uses to store stack traces. Using "slab" is confusing, as stack depot pools have nothing to do with the slab allocator. Also give better names to pool-related global variables: change "depot_" prefix to "pool_" to point out that these variables are related to stack depot pools. Also rename the slabindex (poolindex) field in handle_parts to pool_index to align its name with the pool_index global variable. No functional changes. Link: https://lkml.kernel.org/r/923c507edb350c3b6ef85860f36be489dfc0ad21.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Acked-by: Vlastimil Babka Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 106 +++++++++++++++++++++++------------------------ 1 file changed, 53 insertions(+), 53 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index d1ab53197353e..522e36cf449f6 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -39,7 +39,7 @@ #define DEPOT_STACK_BITS (sizeof(depot_stack_handle_t) * 8) #define STACK_ALLOC_NULL_PROTECTION_BITS 1 -#define STACK_ALLOC_ORDER 2 /* 'Slab' size order for stack depot, 4 pages */ +#define STACK_ALLOC_ORDER 2 /* Pool size order for stack depot, 4 pages */ #define STACK_ALLOC_SIZE (1LL << (PAGE_SHIFT + STACK_ALLOC_ORDER)) #define STACK_ALLOC_ALIGN 4 #define STACK_ALLOC_OFFSET_BITS (STACK_ALLOC_ORDER + PAGE_SHIFT - \ @@ -47,16 +47,16 @@ #define STACK_ALLOC_INDEX_BITS (DEPOT_STACK_BITS - \ STACK_ALLOC_NULL_PROTECTION_BITS - \ STACK_ALLOC_OFFSET_BITS - STACK_DEPOT_EXTRA_BITS) -#define STACK_ALLOC_SLABS_CAP 8192 -#define STACK_ALLOC_MAX_SLABS \ - (((1LL << (STACK_ALLOC_INDEX_BITS)) < STACK_ALLOC_SLABS_CAP) ? \ - (1LL << (STACK_ALLOC_INDEX_BITS)) : STACK_ALLOC_SLABS_CAP) +#define STACK_ALLOC_POOLS_CAP 8192 +#define STACK_ALLOC_MAX_POOLS \ + (((1LL << (STACK_ALLOC_INDEX_BITS)) < STACK_ALLOC_POOLS_CAP) ? \ + (1LL << (STACK_ALLOC_INDEX_BITS)) : STACK_ALLOC_POOLS_CAP) /* The compact structure to store the reference to stacks. */ union handle_parts { depot_stack_handle_t handle; struct { - u32 slabindex : STACK_ALLOC_INDEX_BITS; + u32 pool_index : STACK_ALLOC_INDEX_BITS; u32 offset : STACK_ALLOC_OFFSET_BITS; u32 valid : STACK_ALLOC_NULL_PROTECTION_BITS; u32 extra : STACK_DEPOT_EXTRA_BITS; @@ -91,15 +91,15 @@ static unsigned int stack_bucket_number_order; static unsigned int stack_hash_mask; /* Array of memory regions that store stack traces. */ -static void *stack_slabs[STACK_ALLOC_MAX_SLABS]; -/* Currently used slab in stack_slabs. */ -static int depot_index; -/* Offset to the unused space in the currently used slab. */ -static size_t depot_offset; +static void *stack_pools[STACK_ALLOC_MAX_POOLS]; +/* Currently used pool in stack_pools. */ +static int pool_index; +/* Offset to the unused space in the currently used pool. */ +static size_t pool_offset; /* Lock that protects the variables above. */ -static DEFINE_RAW_SPINLOCK(depot_lock); -/* Whether the next slab is initialized. */ -static int next_slab_inited; +static DEFINE_RAW_SPINLOCK(pool_lock); +/* Whether the next pool is initialized. */ +static int next_pool_inited; static int __init disable_stack_depot(char *str) { @@ -220,30 +220,30 @@ int stack_depot_init(void) } EXPORT_SYMBOL_GPL(stack_depot_init); -static bool init_stack_slab(void **prealloc) +static bool init_stack_pool(void **prealloc) { if (!*prealloc) return false; /* * This smp_load_acquire() pairs with smp_store_release() to - * |next_slab_inited| below and in depot_alloc_stack(). + * |next_pool_inited| below and in depot_alloc_stack(). */ - if (smp_load_acquire(&next_slab_inited)) + if (smp_load_acquire(&next_pool_inited)) return true; - if (stack_slabs[depot_index] == NULL) { - stack_slabs[depot_index] = *prealloc; + if (stack_pools[pool_index] == NULL) { + stack_pools[pool_index] = *prealloc; *prealloc = NULL; } else { - /* If this is the last depot slab, do not touch the next one. */ - if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) { - stack_slabs[depot_index + 1] = *prealloc; + /* If this is the last depot pool, do not touch the next one. */ + if (pool_index + 1 < STACK_ALLOC_MAX_POOLS) { + stack_pools[pool_index + 1] = *prealloc; *prealloc = NULL; } /* * This smp_store_release pairs with smp_load_acquire() from - * |next_slab_inited| above and in stack_depot_save(). + * |next_pool_inited| above and in stack_depot_save(). */ - smp_store_release(&next_slab_inited, 1); + smp_store_release(&next_pool_inited, 1); } return true; } @@ -257,35 +257,35 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN); - if (unlikely(depot_offset + required_size > STACK_ALLOC_SIZE)) { - if (unlikely(depot_index + 1 >= STACK_ALLOC_MAX_SLABS)) { + if (unlikely(pool_offset + required_size > STACK_ALLOC_SIZE)) { + if (unlikely(pool_index + 1 >= STACK_ALLOC_MAX_POOLS)) { WARN_ONCE(1, "Stack depot reached limit capacity"); return NULL; } - depot_index++; - depot_offset = 0; + pool_index++; + pool_offset = 0; /* * smp_store_release() here pairs with smp_load_acquire() from - * |next_slab_inited| in stack_depot_save() and - * init_stack_slab(). + * |next_pool_inited| in stack_depot_save() and + * init_stack_pool(). */ - if (depot_index + 1 < STACK_ALLOC_MAX_SLABS) - smp_store_release(&next_slab_inited, 0); + if (pool_index + 1 < STACK_ALLOC_MAX_POOLS) + smp_store_release(&next_pool_inited, 0); } - init_stack_slab(prealloc); - if (stack_slabs[depot_index] == NULL) + init_stack_pool(prealloc); + if (stack_pools[pool_index] == NULL) return NULL; - stack = stack_slabs[depot_index] + depot_offset; + stack = stack_pools[pool_index] + pool_offset; stack->hash = hash; stack->size = size; - stack->handle.slabindex = depot_index; - stack->handle.offset = depot_offset >> STACK_ALLOC_ALIGN; + stack->handle.pool_index = pool_index; + stack->handle.offset = pool_offset >> STACK_ALLOC_ALIGN; stack->handle.valid = 1; stack->handle.extra = 0; memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); - depot_offset += required_size; + pool_offset += required_size; return stack; } @@ -336,10 +336,10 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, * @nr_entries: Size of the storage array * @extra_bits: Flags to store in unused bits of depot_stack_handle_t * @alloc_flags: Allocation gfp flags - * @can_alloc: Allocate stack slabs (increased chance of failure if false) + * @can_alloc: Allocate stack pools (increased chance of failure if false) * * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is - * %true, is allowed to replenish the stack slab pool in case no space is left + * %true, is allowed to replenish the stack pool in case no space is left * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids * any allocations and will fail if no space is left to store the stack trace. * @@ -396,14 +396,14 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, goto exit; /* - * Check if the current or the next stack slab need to be initialized. + * Check if the current or the next stack pool need to be initialized. * If so, allocate the memory - we won't be able to do that under the * lock. * * The smp_load_acquire() here pairs with smp_store_release() to - * |next_slab_inited| in depot_alloc_stack() and init_stack_slab(). + * |next_pool_inited| in depot_alloc_stack() and init_stack_pool(). */ - if (unlikely(can_alloc && !smp_load_acquire(&next_slab_inited))) { + if (unlikely(can_alloc && !smp_load_acquire(&next_pool_inited))) { /* * Zero out zone modifiers, as we don't have specific zone * requirements. Keep the flags related to allocation in atomic @@ -417,7 +417,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, prealloc = page_address(page); } - raw_spin_lock_irqsave(&depot_lock, flags); + raw_spin_lock_irqsave(&pool_lock, flags); found = find_stack(*bucket, entries, nr_entries, hash); if (!found) { @@ -437,10 +437,10 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * We didn't need to store this stack trace, but let's keep * the preallocated memory for the future. */ - WARN_ON(!init_stack_slab(&prealloc)); + WARN_ON(!init_stack_pool(&prealloc)); } - raw_spin_unlock_irqrestore(&depot_lock, flags); + raw_spin_unlock_irqrestore(&pool_lock, flags); exit: if (prealloc) { /* Nobody used this memory, ok to free it. */ @@ -488,7 +488,7 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries) { union handle_parts parts = { .handle = handle }; - void *slab; + void *pool; size_t offset = parts.offset << STACK_ALLOC_ALIGN; struct stack_record *stack; @@ -496,15 +496,15 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, if (!handle) return 0; - if (parts.slabindex > depot_index) { - WARN(1, "slab index %d out of bounds (%d) for stack id %08x\n", - parts.slabindex, depot_index, handle); + if (parts.pool_index > pool_index) { + WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n", + parts.pool_index, pool_index, handle); return 0; } - slab = stack_slabs[parts.slabindex]; - if (!slab) + pool = stack_pools[parts.pool_index]; + if (!pool) return 0; - stack = slab + offset; + stack = pool + offset; *entries = stack->entries; return stack->size; From a573012edfdd5d3924251d020abea1faecb22a26 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:58 +0100 Subject: [PATCH 41/80] lib/stackdepot: rename handle and pool constants Change the "STACK_ALLOC_" prefix to "DEPOT_" for the constants that define the number of bits in stack depot handles and the maximum number of pools. The old prefix is unclear and makes wonder about how these constants are related to stack allocations. The new prefix is also shorter. Also simplify the comment for DEPOT_POOL_ORDER. No functional changes. Link: https://lkml.kernel.org/r/84fcceb0acc261a356a0ad4bdfab9ff04bea2445.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 56 +++++++++++++++++++++++------------------------- 1 file changed, 27 insertions(+), 29 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 522e36cf449f6..97bba462ee13b 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -36,30 +36,28 @@ #include #include -#define DEPOT_STACK_BITS (sizeof(depot_stack_handle_t) * 8) - -#define STACK_ALLOC_NULL_PROTECTION_BITS 1 -#define STACK_ALLOC_ORDER 2 /* Pool size order for stack depot, 4 pages */ -#define STACK_ALLOC_SIZE (1LL << (PAGE_SHIFT + STACK_ALLOC_ORDER)) -#define STACK_ALLOC_ALIGN 4 -#define STACK_ALLOC_OFFSET_BITS (STACK_ALLOC_ORDER + PAGE_SHIFT - \ - STACK_ALLOC_ALIGN) -#define STACK_ALLOC_INDEX_BITS (DEPOT_STACK_BITS - \ - STACK_ALLOC_NULL_PROTECTION_BITS - \ - STACK_ALLOC_OFFSET_BITS - STACK_DEPOT_EXTRA_BITS) -#define STACK_ALLOC_POOLS_CAP 8192 -#define STACK_ALLOC_MAX_POOLS \ - (((1LL << (STACK_ALLOC_INDEX_BITS)) < STACK_ALLOC_POOLS_CAP) ? \ - (1LL << (STACK_ALLOC_INDEX_BITS)) : STACK_ALLOC_POOLS_CAP) +#define DEPOT_HANDLE_BITS (sizeof(depot_stack_handle_t) * 8) + +#define DEPOT_VALID_BITS 1 +#define DEPOT_POOL_ORDER 2 /* Pool size order, 4 pages */ +#define DEPOT_POOL_SIZE (1LL << (PAGE_SHIFT + DEPOT_POOL_ORDER)) +#define DEPOT_STACK_ALIGN 4 +#define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN) +#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_VALID_BITS - \ + DEPOT_OFFSET_BITS - STACK_DEPOT_EXTRA_BITS) +#define DEPOT_POOLS_CAP 8192 +#define DEPOT_MAX_POOLS \ + (((1LL << (DEPOT_POOL_INDEX_BITS)) < DEPOT_POOLS_CAP) ? \ + (1LL << (DEPOT_POOL_INDEX_BITS)) : DEPOT_POOLS_CAP) /* The compact structure to store the reference to stacks. */ union handle_parts { depot_stack_handle_t handle; struct { - u32 pool_index : STACK_ALLOC_INDEX_BITS; - u32 offset : STACK_ALLOC_OFFSET_BITS; - u32 valid : STACK_ALLOC_NULL_PROTECTION_BITS; - u32 extra : STACK_DEPOT_EXTRA_BITS; + u32 pool_index : DEPOT_POOL_INDEX_BITS; + u32 offset : DEPOT_OFFSET_BITS; + u32 valid : DEPOT_VALID_BITS; + u32 extra : STACK_DEPOT_EXTRA_BITS; }; }; @@ -91,7 +89,7 @@ static unsigned int stack_bucket_number_order; static unsigned int stack_hash_mask; /* Array of memory regions that store stack traces. */ -static void *stack_pools[STACK_ALLOC_MAX_POOLS]; +static void *stack_pools[DEPOT_MAX_POOLS]; /* Currently used pool in stack_pools. */ static int pool_index; /* Offset to the unused space in the currently used pool. */ @@ -235,7 +233,7 @@ static bool init_stack_pool(void **prealloc) *prealloc = NULL; } else { /* If this is the last depot pool, do not touch the next one. */ - if (pool_index + 1 < STACK_ALLOC_MAX_POOLS) { + if (pool_index + 1 < DEPOT_MAX_POOLS) { stack_pools[pool_index + 1] = *prealloc; *prealloc = NULL; } @@ -255,10 +253,10 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) struct stack_record *stack; size_t required_size = struct_size(stack, entries, size); - required_size = ALIGN(required_size, 1 << STACK_ALLOC_ALIGN); + required_size = ALIGN(required_size, 1 << DEPOT_STACK_ALIGN); - if (unlikely(pool_offset + required_size > STACK_ALLOC_SIZE)) { - if (unlikely(pool_index + 1 >= STACK_ALLOC_MAX_POOLS)) { + if (unlikely(pool_offset + required_size > DEPOT_POOL_SIZE)) { + if (unlikely(pool_index + 1 >= DEPOT_MAX_POOLS)) { WARN_ONCE(1, "Stack depot reached limit capacity"); return NULL; } @@ -269,7 +267,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) * |next_pool_inited| in stack_depot_save() and * init_stack_pool(). */ - if (pool_index + 1 < STACK_ALLOC_MAX_POOLS) + if (pool_index + 1 < DEPOT_MAX_POOLS) smp_store_release(&next_pool_inited, 0); } init_stack_pool(prealloc); @@ -281,7 +279,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) stack->hash = hash; stack->size = size; stack->handle.pool_index = pool_index; - stack->handle.offset = pool_offset >> STACK_ALLOC_ALIGN; + stack->handle.offset = pool_offset >> DEPOT_STACK_ALIGN; stack->handle.valid = 1; stack->handle.extra = 0; memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); @@ -412,7 +410,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, alloc_flags &= ~GFP_ZONEMASK; alloc_flags &= (GFP_ATOMIC | GFP_KERNEL); alloc_flags |= __GFP_NOWARN; - page = alloc_pages(alloc_flags, STACK_ALLOC_ORDER); + page = alloc_pages(alloc_flags, DEPOT_POOL_ORDER); if (page) prealloc = page_address(page); } @@ -444,7 +442,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, exit: if (prealloc) { /* Nobody used this memory, ok to free it. */ - free_pages((unsigned long)prealloc, STACK_ALLOC_ORDER); + free_pages((unsigned long)prealloc, DEPOT_POOL_ORDER); } if (found) retval.handle = found->handle.handle; @@ -489,7 +487,7 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, { union handle_parts parts = { .handle = handle }; void *pool; - size_t offset = parts.offset << STACK_ALLOC_ALIGN; + size_t offset = parts.offset << DEPOT_STACK_ALIGN; struct stack_record *stack; *entries = NULL; From d7a599aaf5e0a7cd95007fc34b4746dbe7aba035 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:15:59 +0100 Subject: [PATCH 42/80] lib/stackdepot: rename init_stack_pool Rename init_stack_pool to depot_init_pool to align the name with depot_alloc_stack. No functional changes. Link: https://lkml.kernel.org/r/23106a3e291d8df0aba33c0e2fe86dc596286479.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 97bba462ee13b..7f5f08bb6c3a2 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -218,7 +218,7 @@ int stack_depot_init(void) } EXPORT_SYMBOL_GPL(stack_depot_init); -static bool init_stack_pool(void **prealloc) +static bool depot_init_pool(void **prealloc) { if (!*prealloc) return false; @@ -265,12 +265,12 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) /* * smp_store_release() here pairs with smp_load_acquire() from * |next_pool_inited| in stack_depot_save() and - * init_stack_pool(). + * depot_init_pool(). */ if (pool_index + 1 < DEPOT_MAX_POOLS) smp_store_release(&next_pool_inited, 0); } - init_stack_pool(prealloc); + depot_init_pool(prealloc); if (stack_pools[pool_index] == NULL) return NULL; @@ -399,7 +399,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * lock. * * The smp_load_acquire() here pairs with smp_store_release() to - * |next_pool_inited| in depot_alloc_stack() and init_stack_pool(). + * |next_pool_inited| in depot_alloc_stack() and depot_init_pool(). */ if (unlikely(can_alloc && !smp_load_acquire(&next_pool_inited))) { /* @@ -435,7 +435,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * We didn't need to store this stack trace, but let's keep * the preallocated memory for the future. */ - WARN_ON(!init_stack_pool(&prealloc)); + WARN_ON(!depot_init_pool(&prealloc)); } raw_spin_unlock_irqrestore(&pool_lock, flags); From 4c173585cad1708de2854495941660554565efa5 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:00 +0100 Subject: [PATCH 43/80] lib/stacktrace: drop impossible WARN_ON for depot_init_pool depot_init_pool has two call sites: 1. In depot_alloc_stack with a potentially NULL prealloc. 2. In __stack_depot_save with a non-NULL prealloc. At the same time depot_init_pool can only return false when prealloc is NULL. As the second call site makes sure that prealloc is not NULL, the WARN_ON there can never trigger. Thus, drop the WARN_ON and also move the prealloc check from depot_init_pool to its first call site. Also change the return type of depot_init_pool to void as it now always returns true. Link: https://lkml.kernel.org/r/ce149f9bdcbc80a92549b54da67eafb27f846b7b.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 7f5f08bb6c3a2..d4d988276b910 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -218,16 +218,14 @@ int stack_depot_init(void) } EXPORT_SYMBOL_GPL(stack_depot_init); -static bool depot_init_pool(void **prealloc) +static void depot_init_pool(void **prealloc) { - if (!*prealloc) - return false; /* * This smp_load_acquire() pairs with smp_store_release() to * |next_pool_inited| below and in depot_alloc_stack(). */ if (smp_load_acquire(&next_pool_inited)) - return true; + return; if (stack_pools[pool_index] == NULL) { stack_pools[pool_index] = *prealloc; *prealloc = NULL; @@ -243,7 +241,6 @@ static bool depot_init_pool(void **prealloc) */ smp_store_release(&next_pool_inited, 1); } - return true; } /* Allocation of a new stack in raw storage */ @@ -270,7 +267,8 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) if (pool_index + 1 < DEPOT_MAX_POOLS) smp_store_release(&next_pool_inited, 0); } - depot_init_pool(prealloc); + if (*prealloc) + depot_init_pool(prealloc); if (stack_pools[pool_index] == NULL) return NULL; @@ -435,7 +433,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * We didn't need to store this stack trace, but let's keep * the preallocated memory for the future. */ - WARN_ON(!depot_init_pool(&prealloc)); + depot_init_pool(&prealloc); } raw_spin_unlock_irqrestore(&pool_lock, flags); From dc34b0bbb534cd60e68bf4cf78bd3dc4c560ab50 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:01 +0100 Subject: [PATCH 44/80] lib/stackdepot: annotate depot_init_pool and depot_alloc_stack Clean up the exisiting comments and add new ones to depot_init_pool and depot_alloc_stack. As a part of the clean-up, remove mentions of which variable is accessed by smp_store_release and smp_load_acquire: it is clear as is from the code. Link: https://lkml.kernel.org/r/f80b02951364e6b40deda965b4003de0cd1a532d.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index d4d988276b910..c4bc198c3d938 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -218,32 +218,39 @@ int stack_depot_init(void) } EXPORT_SYMBOL_GPL(stack_depot_init); +/* Uses preallocated memory to initialize a new stack depot pool. */ static void depot_init_pool(void **prealloc) { /* - * This smp_load_acquire() pairs with smp_store_release() to - * |next_pool_inited| below and in depot_alloc_stack(). + * smp_load_acquire() here pairs with smp_store_release() below and + * in depot_alloc_stack(). */ if (smp_load_acquire(&next_pool_inited)) return; + + /* Check if the current pool is not yet allocated. */ if (stack_pools[pool_index] == NULL) { + /* Use the preallocated memory for the current pool. */ stack_pools[pool_index] = *prealloc; *prealloc = NULL; } else { - /* If this is the last depot pool, do not touch the next one. */ + /* + * Otherwise, use the preallocated memory for the next pool + * as long as we do not exceed the maximum number of pools. + */ if (pool_index + 1 < DEPOT_MAX_POOLS) { stack_pools[pool_index + 1] = *prealloc; *prealloc = NULL; } /* - * This smp_store_release pairs with smp_load_acquire() from - * |next_pool_inited| above and in stack_depot_save(). + * This smp_store_release pairs with smp_load_acquire() above + * and in stack_depot_save(). */ smp_store_release(&next_pool_inited, 1); } } -/* Allocation of a new stack in raw storage */ +/* Allocates a new stack in a stack depot pool. */ static struct stack_record * depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) { @@ -252,28 +259,35 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) required_size = ALIGN(required_size, 1 << DEPOT_STACK_ALIGN); + /* Check if there is not enough space in the current pool. */ if (unlikely(pool_offset + required_size > DEPOT_POOL_SIZE)) { + /* Bail out if we reached the pool limit. */ if (unlikely(pool_index + 1 >= DEPOT_MAX_POOLS)) { WARN_ONCE(1, "Stack depot reached limit capacity"); return NULL; } + + /* Move on to the next pool. */ pool_index++; pool_offset = 0; /* - * smp_store_release() here pairs with smp_load_acquire() from - * |next_pool_inited| in stack_depot_save() and - * depot_init_pool(). + * smp_store_release() here pairs with smp_load_acquire() in + * stack_depot_save() and depot_init_pool(). */ if (pool_index + 1 < DEPOT_MAX_POOLS) smp_store_release(&next_pool_inited, 0); } + + /* Assign the preallocated memory to a pool if required. */ if (*prealloc) depot_init_pool(prealloc); + + /* Check if we have a pool to save the stack trace. */ if (stack_pools[pool_index] == NULL) return NULL; + /* Save the stack trace. */ stack = stack_pools[pool_index] + pool_offset; - stack->hash = hash; stack->size = size; stack->handle.pool_index = pool_index; From 7dd29fc7c8e434d458912566a96686f26d94e980 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:02 +0100 Subject: [PATCH 45/80] lib/stackdepot: rename next_pool_inited to next_pool_required Stack depot uses next_pool_inited to mark that either the next pool is initialized or the limit on the number of pools is reached. However, the flag name only reflects the former part of its purpose, which is confusing. Rename next_pool_inited to next_pool_required and invert its value. Also annotate usages of next_pool_required with comments. Link: https://lkml.kernel.org/r/484fd2695dff7a9bdc437a32f8a6ee228535aa02.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index c4bc198c3d938..4df162a84bfe1 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -96,8 +96,14 @@ static int pool_index; static size_t pool_offset; /* Lock that protects the variables above. */ static DEFINE_RAW_SPINLOCK(pool_lock); -/* Whether the next pool is initialized. */ -static int next_pool_inited; +/* + * Stack depot tries to keep an extra pool allocated even before it runs out + * of space in the currently used pool. + * This flag marks that this next extra pool needs to be allocated and + * initialized. It has the value 0 when either the next pool is not yet + * initialized or the limit on the number of pools is reached. + */ +static int next_pool_required = 1; static int __init disable_stack_depot(char *str) { @@ -222,10 +228,12 @@ EXPORT_SYMBOL_GPL(stack_depot_init); static void depot_init_pool(void **prealloc) { /* + * If the next pool is already initialized or the maximum number of + * pools is reached, do not use the preallocated memory. * smp_load_acquire() here pairs with smp_store_release() below and * in depot_alloc_stack(). */ - if (smp_load_acquire(&next_pool_inited)) + if (!smp_load_acquire(&next_pool_required)) return; /* Check if the current pool is not yet allocated. */ @@ -243,10 +251,13 @@ static void depot_init_pool(void **prealloc) *prealloc = NULL; } /* + * At this point, either the next pool is initialized or the + * maximum number of pools is reached. In either case, take + * note that initializing another pool is not required. * This smp_store_release pairs with smp_load_acquire() above * and in stack_depot_save(). */ - smp_store_release(&next_pool_inited, 1); + smp_store_release(&next_pool_required, 0); } } @@ -271,11 +282,13 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) pool_index++; pool_offset = 0; /* + * If the maximum number of pools is not reached, take note + * that the next pool needs to initialized. * smp_store_release() here pairs with smp_load_acquire() in * stack_depot_save() and depot_init_pool(). */ if (pool_index + 1 < DEPOT_MAX_POOLS) - smp_store_release(&next_pool_inited, 0); + smp_store_release(&next_pool_required, 1); } /* Assign the preallocated memory to a pool if required. */ @@ -406,14 +419,13 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, goto exit; /* - * Check if the current or the next stack pool need to be initialized. - * If so, allocate the memory - we won't be able to do that under the - * lock. + * Check if another stack pool needs to be initialized. If so, allocate + * the memory now - we won't be able to do that under the lock. * * The smp_load_acquire() here pairs with smp_store_release() to * |next_pool_inited| in depot_alloc_stack() and depot_init_pool(). */ - if (unlikely(can_alloc && !smp_load_acquire(&next_pool_inited))) { + if (unlikely(can_alloc && smp_load_acquire(&next_pool_required))) { /* * Zero out zone modifiers, as we don't have specific zone * requirements. Keep the flags related to allocation in atomic From 38e4c49325da92af20c85f1e3fd6da31330e5012 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:03 +0100 Subject: [PATCH 46/80] lib/stacktrace, kasan, kmsan: rework extra_bits interface The current implementation of the extra_bits interface is confusing: passing extra_bits to __stack_depot_save makes it seem that the extra bits are somehow stored in stack depot. In reality, they are only embedded into a stack depot handle and are not used within stack depot. Drop the extra_bits argument from __stack_depot_save and instead provide a new stack_depot_set_extra_bits function (similar to the exsiting stack_depot_get_extra_bits) that saves extra bits into a stack depot handle. Update the callers of __stack_depot_save to use the new interace. This change also fixes a minor issue in the old code: __stack_depot_save does not return NULL if saving stack trace fails and extra_bits is used. Link: https://lkml.kernel.org/r/317123b5c05e2f82854fc55d8b285e0869d3cb77.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 4 +++- lib/stackdepot.c | 42 ++++++++++++++++++++++++++++++-------- mm/kasan/common.c | 2 +- mm/kmsan/core.c | 10 ++++++--- 4 files changed, 44 insertions(+), 14 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index c4e3abc16b16a..267f4b2634ee1 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -57,7 +57,6 @@ static inline int stack_depot_early_init(void) { return 0; } depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, - unsigned int extra_bits, gfp_t gfp_flags, bool can_alloc); depot_stack_handle_t stack_depot_save(unsigned long *entries, @@ -71,6 +70,9 @@ void stack_depot_print(depot_stack_handle_t stack); int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces); +depot_stack_handle_t __must_check stack_depot_set_extra_bits( + depot_stack_handle_t handle, unsigned int extra_bits); + unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); #endif diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 4df162a84bfe1..8c6e4e9cb5353 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -357,7 +357,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, * * @entries: Pointer to storage array * @nr_entries: Size of the storage array - * @extra_bits: Flags to store in unused bits of depot_stack_handle_t * @alloc_flags: Allocation gfp flags * @can_alloc: Allocate stack pools (increased chance of failure if false) * @@ -369,10 +368,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, * If the stack trace in @entries is from an interrupt, only the portion up to * interrupt entry is saved. * - * Additional opaque flags can be passed in @extra_bits, stored in the unused - * bits of the stack handle, and retrieved using stack_depot_get_extra_bits() - * without calling stack_depot_fetch(). - * * Context: Any context, but setting @can_alloc to %false is required if * alloc_pages() cannot be used from the current context. Currently * this is the case from contexts where neither %GFP_ATOMIC nor @@ -382,7 +377,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, - unsigned int extra_bits, gfp_t alloc_flags, bool can_alloc) { struct stack_record *found = NULL, **bucket; @@ -471,8 +465,6 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, if (found) retval.handle = found->handle.handle; fast_exit: - retval.extra = extra_bits; - return retval.handle; } EXPORT_SYMBOL_GPL(__stack_depot_save); @@ -493,7 +485,7 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t alloc_flags) { - return __stack_depot_save(entries, nr_entries, 0, alloc_flags, true); + return __stack_depot_save(entries, nr_entries, alloc_flags, true); } EXPORT_SYMBOL_GPL(stack_depot_save); @@ -576,6 +568,38 @@ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, } EXPORT_SYMBOL_GPL(stack_depot_snprint); +/** + * stack_depot_set_extra_bits - Set extra bits in a stack depot handle + * + * @handle: Stack depot handle returned from stack_depot_save() + * @extra_bits: Value to set the extra bits + * + * Return: Stack depot handle with extra bits set + * + * Stack depot handles have a few unused bits, which can be used for storing + * user-specific information. These bits are transparent to the stack depot. + */ +depot_stack_handle_t __must_check stack_depot_set_extra_bits( + depot_stack_handle_t handle, unsigned int extra_bits) +{ + union handle_parts parts = { .handle = handle }; + + /* Don't set extra bits on empty handles. */ + if (!handle) + return 0; + + parts.extra = extra_bits; + return parts.handle; +} +EXPORT_SYMBOL(stack_depot_set_extra_bits); + +/** + * stack_depot_get_extra_bits - Retrieve extra bits from a stack depot handle + * + * @handle: Stack depot handle with extra bits saved + * + * Return: Extra bits retrieved from the stack depot handle + */ unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) { union handle_parts parts = { .handle = handle }; diff --git a/mm/kasan/common.c b/mm/kasan/common.c index 1e7336ae37864..b376a5d055e55 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -43,7 +43,7 @@ depot_stack_handle_t kasan_save_stack(gfp_t flags, bool can_alloc) unsigned int nr_entries; nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 0); - return __stack_depot_save(entries, nr_entries, 0, flags, can_alloc); + return __stack_depot_save(entries, nr_entries, flags, can_alloc); } void kasan_set_track(struct kasan_track *track, gfp_t flags) diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c index 112dce135c7f6..f710257d68670 100644 --- a/mm/kmsan/core.c +++ b/mm/kmsan/core.c @@ -69,13 +69,15 @@ depot_stack_handle_t kmsan_save_stack_with_flags(gfp_t flags, { unsigned long entries[KMSAN_STACK_DEPTH]; unsigned int nr_entries; + depot_stack_handle_t handle; nr_entries = stack_trace_save(entries, KMSAN_STACK_DEPTH, 0); /* Don't sleep (see might_sleep_if() in __alloc_pages_nodemask()). */ flags &= ~__GFP_DIRECT_RECLAIM; - return __stack_depot_save(entries, nr_entries, extra, flags, true); + handle = __stack_depot_save(entries, nr_entries, flags, true); + return stack_depot_set_extra_bits(handle, extra); } /* Copy the metadata following the memmove() behavior. */ @@ -215,6 +217,7 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id) u32 extra_bits; int depth; bool uaf; + depot_stack_handle_t handle; if (!id) return id; @@ -250,8 +253,9 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id) * positives when __stack_depot_save() passes it to instrumented code. */ kmsan_internal_unpoison_memory(entries, sizeof(entries), false); - return __stack_depot_save(entries, ARRAY_SIZE(entries), extra_bits, - GFP_ATOMIC, true); + handle = __stack_depot_save(entries, ARRAY_SIZE(entries), GFP_ATOMIC, + true); + return stack_depot_set_extra_bits(handle, extra_bits); } void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, From 275aea1ee313f7c85b757be930f012107406824a Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:04 +0100 Subject: [PATCH 47/80] lib/stackdepot: annotate racy pool_index accesses Accesses to pool_index are protected by pool_lock everywhere except in a sanity check in stack_depot_fetch. The read access there can race with the write access in depot_alloc_stack. Use WRITE/READ_ONCE() to annotate the racy accesses. As the sanity check is only used to print a warning in case of a violation of the stack depot interface usage, it does not make a lot of sense to use proper synchronization. Link: https://lkml.kernel.org/r/359ac9c13cd0869c56740fb2029f505e41593830.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- lib/stackdepot.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 8c6e4e9cb5353..684c2168bed9e 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -278,8 +278,12 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) return NULL; } - /* Move on to the next pool. */ - pool_index++; + /* + * Move on to the next pool. + * WRITE_ONCE pairs with potential concurrent read in + * stack_depot_fetch(). + */ + WRITE_ONCE(pool_index, pool_index + 1); pool_offset = 0; /* * If the maximum number of pools is not reached, take note @@ -502,6 +506,11 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries) { union handle_parts parts = { .handle = handle }; + /* + * READ_ONCE pairs with potential concurrent write in + * depot_alloc_stack. + */ + int pool_index_cached = READ_ONCE(pool_index); void *pool; size_t offset = parts.offset << DEPOT_STACK_ALIGN; struct stack_record *stack; @@ -510,7 +519,7 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, if (!handle) return 0; - if (parts.pool_index > pool_index) { + if (parts.pool_index > pool_index_cached) { WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n", parts.pool_index, pool_index, handle); return 0; From ceea793bb3724351cacf563574f6074560d38ede Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Sat, 11 Feb 2023 16:48:42 +0100 Subject: [PATCH 48/80] lib/stackdepot: fix for "annotate racy pool_index accesses" Change the remaining reference to pool_index in stack_depot_fetch to pool_index_cached. Link: https://lkml.kernel.org/r/95cf53f0da2c112aa2cc54456cbcd6975c3ff343.1676129911.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Cc: Alexander Potapenko Cc: Evgenii Stepanov Cc: Marco Elver Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- lib/stackdepot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 684c2168bed9e..b625090890e14 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -521,7 +521,7 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, if (parts.pool_index > pool_index_cached) { WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n", - parts.pool_index, pool_index, handle); + parts.pool_index, pool_index_cached, handle); return 0; } pool = stack_pools[parts.pool_index]; From 3c071555f8251a285707255ef21686f96e836b07 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:05 +0100 Subject: [PATCH 49/80] lib/stackdepot: various comments clean-ups Clean up comments in include/linux/stackdepot.h and lib/stackdepot.c: 1. Rework the initialization comment in stackdepot.h. 2. Rework the header comment in stackdepot.c. 3. Various clean-ups for other comments. Also adjust whitespaces for find_stack and depot_alloc_stack call sites. No functional changes. Link: https://lkml.kernel.org/r/5836231b7954355e2311fc9b5870f697ea8e1f7d.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 36 +++++------ lib/stackdepot.c | 120 ++++++++++++++++++------------------- 2 files changed, 78 insertions(+), 78 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 267f4b2634ee1..afdf8ee7b597a 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -1,11 +1,11 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ /* - * A generic stack depot implementation + * Stack depot - a stack trace storage that avoids duplication. * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * - * Based on code by Dmitry Chernenkov. + * Based on the code by Dmitry Chernenkov. */ #ifndef _LINUX_STACKDEPOT_H @@ -17,35 +17,37 @@ typedef u32 depot_stack_handle_t; /* * Number of bits in the handle that stack depot doesn't use. Users may store - * information in them. + * information in them via stack_depot_set/get_extra_bits. */ #define STACK_DEPOT_EXTRA_BITS 5 /* - * Every user of stack depot has to call stack_depot_init() during its own init - * when it's decided that it will be calling stack_depot_save() later. This is - * recommended for e.g. modules initialized later in the boot process, when - * slab_is_available() is true. + * Using stack depot requires its initialization, which can be done in 3 ways: * - * The alternative is to select STACKDEPOT_ALWAYS_INIT to have stack depot - * enabled as part of mm_init(), for subsystems where it's known at compile time - * that stack depot will be used. + * 1. Selecting CONFIG_STACKDEPOT_ALWAYS_INIT. This option is suitable in + * scenarios where it's known at compile time that stack depot will be used. + * Enabling this config makes the kernel initialize stack depot in mm_init(). * - * Another alternative is to call stack_depot_request_early_init(), when the - * decision to use stack depot is taken e.g. when evaluating kernel boot - * parameters, which precedes the enablement point in mm_init(). + * 2. Calling stack_depot_request_early_init() during early boot, before + * stack_depot_early_init() in mm_init() completes. For example, this can + * be done when evaluating kernel boot parameters. + * + * 3. Calling stack_depot_init(). Possible after boot is complete. This option + * is recommended for modules initialized later in the boot process, after + * mm_init() completes. * * stack_depot_init() and stack_depot_request_early_init() can be called - * regardless of CONFIG_STACKDEPOT and are no-op when disabled. The actual - * save/fetch/print functions should only be called from code that makes sure - * CONFIG_STACKDEPOT is enabled. + * regardless of whether CONFIG_STACKDEPOT is enabled and are no-op when this + * config is disabled. The save/fetch/print stack depot functions can only be + * called from the code that makes sure CONFIG_STACKDEPOT is enabled _and_ + * initializes stack depot via one of the ways listed above. */ #ifdef CONFIG_STACKDEPOT int stack_depot_init(void); void __init stack_depot_request_early_init(void); -/* This is supposed to be called only from mm_init() */ +/* Must be only called from mm_init(). */ int __init stack_depot_early_init(void); #else static inline int stack_depot_init(void) { return 0; } diff --git a/lib/stackdepot.c b/lib/stackdepot.c index b625090890e14..aaa5d2f1abc27 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -1,22 +1,26 @@ // SPDX-License-Identifier: GPL-2.0-only /* - * Generic stack depot for storing stack traces. + * Stack depot - a stack trace storage that avoids duplication. * - * Some debugging tools need to save stack traces of certain events which can - * be later presented to the user. For example, KASAN needs to safe alloc and - * free stacks for each object, but storing two stack traces per object - * requires too much memory (e.g. SLUB_DEBUG needs 256 bytes per object for - * that). + * Stack depot is intended to be used by subsystems that need to store and + * later retrieve many potentially duplicated stack traces without wasting + * memory. * - * Instead, stack depot maintains a hashtable of unique stacktraces. Since alloc - * and free stacks repeat a lot, we save about 100x space. - * Stacks are never removed from depot, so we store them contiguously one after - * another in a contiguous memory allocation. + * For example, KASAN needs to save allocation and free stack traces for each + * object. Storing two stack traces per object requires a lot of memory (e.g. + * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free + * stack traces often repeat, using stack depot allows to save about 100x space. + * + * Internally, stack depot maintains a hash table of unique stacktraces. The + * stack traces themselves are stored contiguously one after another in a set + * of separate page allocations. + * + * Stack traces are never removed from stack depot. * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * - * Based on code by Dmitry Chernenkov. + * Based on the code by Dmitry Chernenkov. */ #define pr_fmt(fmt) "stackdepot: " fmt @@ -50,7 +54,7 @@ (((1LL << (DEPOT_POOL_INDEX_BITS)) < DEPOT_POOLS_CAP) ? \ (1LL << (DEPOT_POOL_INDEX_BITS)) : DEPOT_POOLS_CAP) -/* The compact structure to store the reference to stacks. */ +/* Compact structure that stores a reference to a stack. */ union handle_parts { depot_stack_handle_t handle; struct { @@ -62,11 +66,11 @@ union handle_parts { }; struct stack_record { - struct stack_record *next; /* Link in the hashtable */ - u32 hash; /* Hash in the hastable */ - u32 size; /* Number of frames in the stack */ + struct stack_record *next; /* Link in the hash table */ + u32 hash; /* Hash in the hash table */ + u32 size; /* Number of stored frames */ union handle_parts handle; - unsigned long entries[]; /* Variable-sized array of entries. */ + unsigned long entries[]; /* Variable-sized array of frames */ }; static bool stack_depot_disabled; @@ -317,7 +321,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) return stack; } -/* Calculate hash for a stack */ +/* Calculates the hash for a stack. */ static inline u32 hash_stack(unsigned long *entries, unsigned int size) { return jhash2((u32 *)entries, @@ -325,9 +329,9 @@ static inline u32 hash_stack(unsigned long *entries, unsigned int size) STACK_HASH_SEED); } -/* Use our own, non-instrumented version of memcmp(). - * - * We actually don't care about the order, just the equality. +/* + * Non-instrumented version of memcmp(). + * Does not check the lexicographical order, only the equality. */ static inline int stackdepot_memcmp(const unsigned long *u1, const unsigned long *u2, @@ -340,7 +344,7 @@ int stackdepot_memcmp(const unsigned long *u1, const unsigned long *u2, return 0; } -/* Find a stack that is equal to the one stored in entries in the hash */ +/* Finds a stack in a bucket of the hash table. */ static inline struct stack_record *find_stack(struct stack_record *bucket, unsigned long *entries, int size, u32 hash) @@ -357,27 +361,27 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, } /** - * __stack_depot_save - Save a stack trace from an array + * __stack_depot_save - Save a stack trace to stack depot * - * @entries: Pointer to storage array - * @nr_entries: Size of the storage array - * @alloc_flags: Allocation gfp flags + * @entries: Pointer to the stack trace + * @nr_entries: Number of frames in the stack + * @alloc_flags: Allocation GFP flags * @can_alloc: Allocate stack pools (increased chance of failure if false) * * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is - * %true, is allowed to replenish the stack pool in case no space is left + * %true, stack depot can replenish the stack pools in case no space is left * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids - * any allocations and will fail if no space is left to store the stack trace. + * any allocations and fails if no space is left to store the stack trace. * - * If the stack trace in @entries is from an interrupt, only the portion up to - * interrupt entry is saved. + * If the provided stack trace comes from the interrupt context, only the part + * up to the interrupt entry is saved. * * Context: Any context, but setting @can_alloc to %false is required if * alloc_pages() cannot be used from the current context. Currently - * this is the case from contexts where neither %GFP_ATOMIC nor + * this is the case for contexts where neither %GFP_ATOMIC nor * %GFP_NOWAIT can be used (NMI, raw_spin_lock). * - * Return: The handle of the stack struct stored in depot, 0 on failure. + * Return: Handle of the stack struct stored in depot, 0 on failure */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, @@ -392,11 +396,11 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, /* * If this stack trace is from an interrupt, including anything before - * interrupt entry usually leads to unbounded stackdepot growth. + * interrupt entry usually leads to unbounded stack depot growth. * - * Because use of filter_irq_stacks() is a requirement to ensure - * stackdepot can efficiently deduplicate interrupt stacks, always - * filter_irq_stacks() to simplify all callers' use of stackdepot. + * Since use of filter_irq_stacks() is a requirement to ensure stack + * depot can efficiently deduplicate interrupt stacks, always + * filter_irq_stacks() to simplify all callers' use of stack depot. */ nr_entries = filter_irq_stacks(entries, nr_entries); @@ -411,8 +415,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, * The smp_load_acquire() here pairs with smp_store_release() to * |bucket| below. */ - found = find_stack(smp_load_acquire(bucket), entries, - nr_entries, hash); + found = find_stack(smp_load_acquire(bucket), entries, nr_entries, hash); if (found) goto exit; @@ -441,7 +444,8 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, found = find_stack(*bucket, entries, nr_entries, hash); if (!found) { - struct stack_record *new = depot_alloc_stack(entries, nr_entries, hash, &prealloc); + struct stack_record *new = + depot_alloc_stack(entries, nr_entries, hash, &prealloc); if (new) { new->next = *bucket; @@ -454,8 +458,8 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, } } else if (prealloc) { /* - * We didn't need to store this stack trace, but let's keep - * the preallocated memory for the future. + * Stack depot already contains this stack trace, but let's + * keep the preallocated memory for the future. */ depot_init_pool(&prealloc); } @@ -463,7 +467,7 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, raw_spin_unlock_irqrestore(&pool_lock, flags); exit: if (prealloc) { - /* Nobody used this memory, ok to free it. */ + /* Stack depot didn't use this memory, free it. */ free_pages((unsigned long)prealloc, DEPOT_POOL_ORDER); } if (found) @@ -474,16 +478,16 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, EXPORT_SYMBOL_GPL(__stack_depot_save); /** - * stack_depot_save - Save a stack trace from an array + * stack_depot_save - Save a stack trace to stack depot * - * @entries: Pointer to storage array - * @nr_entries: Size of the storage array - * @alloc_flags: Allocation gfp flags + * @entries: Pointer to the stack trace + * @nr_entries: Number of frames in the stack + * @alloc_flags: Allocation GFP flags * * Context: Contexts where allocations via alloc_pages() are allowed. * See __stack_depot_save() for more details. * - * Return: The handle of the stack struct stored in depot, 0 on failure. + * Return: Handle of the stack trace stored in depot, 0 on failure */ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, @@ -494,13 +498,12 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, EXPORT_SYMBOL_GPL(stack_depot_save); /** - * stack_depot_fetch - Fetch stack entries from a depot + * stack_depot_fetch - Fetch a stack trace from stack depot * - * @handle: Stack depot handle which was returned from - * stack_depot_save(). - * @entries: Pointer to store the entries address + * @handle: Stack depot handle returned from stack_depot_save() + * @entries: Pointer to store the address of the stack trace * - * Return: The number of trace entries for this depot. + * Return: Number of frames for the fetched stack */ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries) @@ -535,11 +538,9 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, EXPORT_SYMBOL_GPL(stack_depot_fetch); /** - * stack_depot_print - print stack entries from a depot - * - * @stack: Stack depot handle which was returned from - * stack_depot_save(). + * stack_depot_print - Print a stack trace from stack depot * + * @stack: Stack depot handle returned from stack_depot_save() */ void stack_depot_print(depot_stack_handle_t stack) { @@ -553,17 +554,14 @@ void stack_depot_print(depot_stack_handle_t stack) EXPORT_SYMBOL_GPL(stack_depot_print); /** - * stack_depot_snprint - print stack entries from a depot into a buffer + * stack_depot_snprint - Print a stack trace from stack depot into a buffer * - * @handle: Stack depot handle which was returned from - * stack_depot_save(). + * @handle: Stack depot handle returned from stack_depot_save() * @buf: Pointer to the print buffer - * * @size: Size of the print buffer - * * @spaces: Number of leading spaces to print * - * Return: Number of bytes printed. + * Return: Number of bytes printed */ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces) From 949cf637955e0ef9558e80153bf770a5f6697873 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Fri, 10 Feb 2023 22:16:06 +0100 Subject: [PATCH 50/80] lib/stackdepot: move documentation comments to stackdepot.h Move all interface- and usage-related documentation comments to include/linux/stackdepot.h. It makes sense to have them in the header where they are available to the interface users. Link: https://lkml.kernel.org/r/fbfee41495b306dd8881f9b1c1b80999c885e82f.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Alexander Potapenko Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 87 ++++++++++++++++++++++++++++++++++++++ lib/stackdepot.c | 87 -------------------------------------- 2 files changed, 87 insertions(+), 87 deletions(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index afdf8ee7b597a..91f038829eaad 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -2,6 +2,17 @@ /* * Stack depot - a stack trace storage that avoids duplication. * + * Stack depot is intended to be used by subsystems that need to store and + * later retrieve many potentially duplicated stack traces without wasting + * memory. + * + * For example, KASAN needs to save allocation and free stack traces for each + * object. Storing two stack traces per object requires a lot of memory (e.g. + * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free + * stack traces often repeat, using stack depot allows to save about 100x space. + * + * Stack traces are never removed from stack depot. + * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * @@ -57,24 +68,100 @@ static inline void stack_depot_request_early_init(void) { } static inline int stack_depot_early_init(void) { return 0; } #endif +/** + * __stack_depot_save - Save a stack trace to stack depot + * + * @entries: Pointer to the stack trace + * @nr_entries: Number of frames in the stack + * @alloc_flags: Allocation GFP flags + * @can_alloc: Allocate stack pools (increased chance of failure if false) + * + * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is + * %true, stack depot can replenish the stack pools in case no space is left + * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids + * any allocations and fails if no space is left to store the stack trace. + * + * If the provided stack trace comes from the interrupt context, only the part + * up to the interrupt entry is saved. + * + * Context: Any context, but setting @can_alloc to %false is required if + * alloc_pages() cannot be used from the current context. Currently + * this is the case for contexts where neither %GFP_ATOMIC nor + * %GFP_NOWAIT can be used (NMI, raw_spin_lock). + * + * Return: Handle of the stack struct stored in depot, 0 on failure + */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags, bool can_alloc); +/** + * stack_depot_save - Save a stack trace to stack depot + * + * @entries: Pointer to the stack trace + * @nr_entries: Number of frames in the stack + * @alloc_flags: Allocation GFP flags + * + * Context: Contexts where allocations via alloc_pages() are allowed. + * See __stack_depot_save() for more details. + * + * Return: Handle of the stack trace stored in depot, 0 on failure + */ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t gfp_flags); +/** + * stack_depot_fetch - Fetch a stack trace from stack depot + * + * @handle: Stack depot handle returned from stack_depot_save() + * @entries: Pointer to store the address of the stack trace + * + * Return: Number of frames for the fetched stack + */ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries); +/** + * stack_depot_print - Print a stack trace from stack depot + * + * @stack: Stack depot handle returned from stack_depot_save() + */ void stack_depot_print(depot_stack_handle_t stack); +/** + * stack_depot_snprint - Print a stack trace from stack depot into a buffer + * + * @handle: Stack depot handle returned from stack_depot_save() + * @buf: Pointer to the print buffer + * @size: Size of the print buffer + * @spaces: Number of leading spaces to print + * + * Return: Number of bytes printed + */ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces); +/** + * stack_depot_set_extra_bits - Set extra bits in a stack depot handle + * + * @handle: Stack depot handle returned from stack_depot_save() + * @extra_bits: Value to set the extra bits + * + * Return: Stack depot handle with extra bits set + * + * Stack depot handles have a few unused bits, which can be used for storing + * user-specific information. These bits are transparent to the stack depot. + */ depot_stack_handle_t __must_check stack_depot_set_extra_bits( depot_stack_handle_t handle, unsigned int extra_bits); +/** + * stack_depot_get_extra_bits - Retrieve extra bits from a stack depot handle + * + * @handle: Stack depot handle with extra bits saved + * + * Return: Extra bits retrieved from the stack depot handle + */ unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle); #endif diff --git a/lib/stackdepot.c b/lib/stackdepot.c index aaa5d2f1abc27..036da8e295d19 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -2,21 +2,10 @@ /* * Stack depot - a stack trace storage that avoids duplication. * - * Stack depot is intended to be used by subsystems that need to store and - * later retrieve many potentially duplicated stack traces without wasting - * memory. - * - * For example, KASAN needs to save allocation and free stack traces for each - * object. Storing two stack traces per object requires a lot of memory (e.g. - * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free - * stack traces often repeat, using stack depot allows to save about 100x space. - * * Internally, stack depot maintains a hash table of unique stacktraces. The * stack traces themselves are stored contiguously one after another in a set * of separate page allocations. * - * Stack traces are never removed from stack depot. - * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. * @@ -360,29 +349,6 @@ static inline struct stack_record *find_stack(struct stack_record *bucket, return NULL; } -/** - * __stack_depot_save - Save a stack trace to stack depot - * - * @entries: Pointer to the stack trace - * @nr_entries: Number of frames in the stack - * @alloc_flags: Allocation GFP flags - * @can_alloc: Allocate stack pools (increased chance of failure if false) - * - * Saves a stack trace from @entries array of size @nr_entries. If @can_alloc is - * %true, stack depot can replenish the stack pools in case no space is left - * (allocates using GFP flags of @alloc_flags). If @can_alloc is %false, avoids - * any allocations and fails if no space is left to store the stack trace. - * - * If the provided stack trace comes from the interrupt context, only the part - * up to the interrupt entry is saved. - * - * Context: Any context, but setting @can_alloc to %false is required if - * alloc_pages() cannot be used from the current context. Currently - * this is the case for contexts where neither %GFP_ATOMIC nor - * %GFP_NOWAIT can be used (NMI, raw_spin_lock). - * - * Return: Handle of the stack struct stored in depot, 0 on failure - */ depot_stack_handle_t __stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t alloc_flags, bool can_alloc) @@ -477,18 +443,6 @@ depot_stack_handle_t __stack_depot_save(unsigned long *entries, } EXPORT_SYMBOL_GPL(__stack_depot_save); -/** - * stack_depot_save - Save a stack trace to stack depot - * - * @entries: Pointer to the stack trace - * @nr_entries: Number of frames in the stack - * @alloc_flags: Allocation GFP flags - * - * Context: Contexts where allocations via alloc_pages() are allowed. - * See __stack_depot_save() for more details. - * - * Return: Handle of the stack trace stored in depot, 0 on failure - */ depot_stack_handle_t stack_depot_save(unsigned long *entries, unsigned int nr_entries, gfp_t alloc_flags) @@ -497,14 +451,6 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, } EXPORT_SYMBOL_GPL(stack_depot_save); -/** - * stack_depot_fetch - Fetch a stack trace from stack depot - * - * @handle: Stack depot handle returned from stack_depot_save() - * @entries: Pointer to store the address of the stack trace - * - * Return: Number of frames for the fetched stack - */ unsigned int stack_depot_fetch(depot_stack_handle_t handle, unsigned long **entries) { @@ -537,11 +483,6 @@ unsigned int stack_depot_fetch(depot_stack_handle_t handle, } EXPORT_SYMBOL_GPL(stack_depot_fetch); -/** - * stack_depot_print - Print a stack trace from stack depot - * - * @stack: Stack depot handle returned from stack_depot_save() - */ void stack_depot_print(depot_stack_handle_t stack) { unsigned long *entries; @@ -553,16 +494,6 @@ void stack_depot_print(depot_stack_handle_t stack) } EXPORT_SYMBOL_GPL(stack_depot_print); -/** - * stack_depot_snprint - Print a stack trace from stack depot into a buffer - * - * @handle: Stack depot handle returned from stack_depot_save() - * @buf: Pointer to the print buffer - * @size: Size of the print buffer - * @spaces: Number of leading spaces to print - * - * Return: Number of bytes printed - */ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, int spaces) { @@ -575,17 +506,6 @@ int stack_depot_snprint(depot_stack_handle_t handle, char *buf, size_t size, } EXPORT_SYMBOL_GPL(stack_depot_snprint); -/** - * stack_depot_set_extra_bits - Set extra bits in a stack depot handle - * - * @handle: Stack depot handle returned from stack_depot_save() - * @extra_bits: Value to set the extra bits - * - * Return: Stack depot handle with extra bits set - * - * Stack depot handles have a few unused bits, which can be used for storing - * user-specific information. These bits are transparent to the stack depot. - */ depot_stack_handle_t __must_check stack_depot_set_extra_bits( depot_stack_handle_t handle, unsigned int extra_bits) { @@ -600,13 +520,6 @@ depot_stack_handle_t __must_check stack_depot_set_extra_bits( } EXPORT_SYMBOL(stack_depot_set_extra_bits); -/** - * stack_depot_get_extra_bits - Retrieve extra bits from a stack depot handle - * - * @handle: Stack depot handle with extra bits saved - * - * Return: Extra bits retrieved from the stack depot handle - */ unsigned int stack_depot_get_extra_bits(depot_stack_handle_t handle) { union handle_parts parts = { .handle = handle }; From 896f8c7d04cb0470887450738a3f9b75047060a8 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Mon, 13 Feb 2023 10:04:04 -0800 Subject: [PATCH 51/80] lib-stackdepot-move-documentation-comments-to-stackdepoth-fix grammar fix, per Alexander Cc: Alexander Potapenko Cc: Andrey Konovalov Signed-off-by: Andrew Morton --- include/linux/stackdepot.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 91f038829eaad..e58306783d8e7 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -11,7 +11,7 @@ * SLUB_DEBUG needs 256 bytes per object for that). Since allocation and free * stack traces often repeat, using stack depot allows to save about 100x space. * - * Stack traces are never removed from stack depot. + * Stack traces are never removed from the stack depot. * * Author: Alexander Potapenko * Copyright (C) 2016 Google, Inc. From 04f70ba933707e822a422efa4fef730b116d2576 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:36 +0800 Subject: [PATCH 52/80] migrate_pages: organize stats with struct migrate_pages_stats Patch series "migrate_pages(): batch TLB flushing", v5. Now, migrate_pages() migrates folios one by one, like the fake code as follows, for each folio unmap flush TLB copy restore map If multiple folios are passed to migrate_pages(), there are opportunities to batch the TLB flushing and copying. That is, we can change the code to something as follows, for each folio unmap for each folio flush TLB for each folio copy for each folio restore map The total number of TLB flushing IPI can be reduced considerably. And we may use some hardware accelerator such as DSA to accelerate the folio copying. So in this patch, we refactor the migrate_pages() implementation and implement the TLB flushing batching. Base on this, hardware accelerated folio copying can be implemented. If too many folios are passed to migrate_pages(), in the naive batched implementation, we may unmap too many folios at the same time. The possibility for a task to wait for the migrated folios to be mapped again increases. So the latency may be hurt. To deal with this issue, the max number of folios be unmapped in batch is restricted to no more than HPAGE_PMD_NR in the unit of page. That is, the influence is at the same level of THP migration. We use the following test to measure the performance impact of the patchset, On a 2-socket Intel server, - Run pmbench memory accessing benchmark - Run `migratepages` to migrate pages of pmbench between node 0 and node 1 back and forth. With the patch, the TLB flushing IPI reduces 99.1% during the test and the number of pages migrated successfully per second increases 291.7%. Xin Hao helped to test the patchset on an ARM64 server with 128 cores, 2 NUMA nodes. Test results show that the page migration performance increases up to 78%. This patch (of 9): Define struct migrate_pages_stats to organize the various statistics in migrate_pages(). This makes it easier to collect and consume the statistics in multiple functions. This will be needed in the following patches in the series. Link: https://lkml.kernel.org/r/20230213123444.155149-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20230213123444.155149-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Alistair Popple Reviewed-by: Zi Yan Reviewed-by: Baolin Wang Reviewed-by: Xin Hao Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 60 +++++++++++++++++++++++++++++----------------------- 1 file changed, 34 insertions(+), 26 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index b3dba30d4f64c..814c2187d5a40 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1416,6 +1416,16 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f return rc; } +struct migrate_pages_stats { + int nr_succeeded; /* Normal and large folios migrated successfully, in + units of base pages */ + int nr_failed_pages; /* Normal and large folios failed to be migrated, in + units of base pages. Untried folios aren't counted */ + int nr_thp_succeeded; /* THP migrated successfully */ + int nr_thp_failed; /* THP failed to be migrated */ + int nr_thp_split; /* THP split before migrating */ +}; + /* * migrate_pages - migrate the folios specified in a list, to the free folios * supplied as the target for the page migration @@ -1450,13 +1460,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, int large_retry = 1; int thp_retry = 1; int nr_failed = 0; - int nr_failed_pages = 0; int nr_retry_pages = 0; - int nr_succeeded = 0; - int nr_thp_succeeded = 0; int nr_large_failed = 0; - int nr_thp_failed = 0; - int nr_thp_split = 0; int pass = 0; bool is_large = false; bool is_thp = false; @@ -1466,9 +1471,11 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_split_folio_counting = false; + struct migrate_pages_stats stats; trace_mm_migrate_pages_start(mode, reason); + memset(&stats, 0, sizeof(stats)); split_folio_migration: for (pass = 0; pass < 10 && (retry || large_retry); pass++) { retry = 0; @@ -1522,9 +1529,9 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, /* Large folio migration is unsupported */ if (is_large) { nr_large_failed++; - nr_thp_failed += is_thp; + stats.nr_thp_failed += is_thp; if (!try_split_folio(folio, &split_folios)) { - nr_thp_split += is_thp; + stats.nr_thp_split += is_thp; break; } /* Hugetlb migration is unsupported */ @@ -1532,7 +1539,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, nr_failed++; } - nr_failed_pages += nr_pages; + stats.nr_failed_pages += nr_pages; list_move_tail(&folio->lru, &ret_folios); break; case -ENOMEM: @@ -1542,13 +1549,13 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ if (is_large) { nr_large_failed++; - nr_thp_failed += is_thp; + stats.nr_thp_failed += is_thp; /* Large folio NUMA faulting doesn't split to retry. */ if (!nosplit) { int ret = try_split_folio(folio, &split_folios); if (!ret) { - nr_thp_split += is_thp; + stats.nr_thp_split += is_thp; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1566,7 +1573,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, nr_failed++; } - nr_failed_pages += nr_pages + nr_retry_pages; + stats.nr_failed_pages += nr_pages + nr_retry_pages; /* * There might be some split folios of fail-to-migrate large * folios left in split_folios list. Move them back to migration @@ -1576,7 +1583,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, list_splice_init(&split_folios, from); /* nr_failed isn't updated for not used */ nr_large_failed += large_retry; - nr_thp_failed += thp_retry; + stats.nr_thp_failed += thp_retry; goto out; case -EAGAIN: if (is_large) { @@ -1588,8 +1595,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, nr_retry_pages += nr_pages; break; case MIGRATEPAGE_SUCCESS: - nr_succeeded += nr_pages; - nr_thp_succeeded += is_thp; + stats.nr_succeeded += nr_pages; + stats.nr_thp_succeeded += is_thp; break; default: /* @@ -1600,20 +1607,20 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ if (is_large) { nr_large_failed++; - nr_thp_failed += is_thp; + stats.nr_thp_failed += is_thp; } else if (!no_split_folio_counting) { nr_failed++; } - nr_failed_pages += nr_pages; + stats.nr_failed_pages += nr_pages; break; } } } nr_failed += retry; nr_large_failed += large_retry; - nr_thp_failed += thp_retry; - nr_failed_pages += nr_retry_pages; + stats.nr_thp_failed += thp_retry; + stats.nr_failed_pages += nr_retry_pages; /* * Try to migrate split folios of fail-to-migrate large folios, no * nr_failed counting in this round, since all split folios of a @@ -1646,16 +1653,17 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, if (list_empty(from)) rc = 0; - count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); - count_vm_events(PGMIGRATE_FAIL, nr_failed_pages); - count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded); - count_vm_events(THP_MIGRATION_FAIL, nr_thp_failed); - count_vm_events(THP_MIGRATION_SPLIT, nr_thp_split); - trace_mm_migrate_pages(nr_succeeded, nr_failed_pages, nr_thp_succeeded, - nr_thp_failed, nr_thp_split, mode, reason); + count_vm_events(PGMIGRATE_SUCCESS, stats.nr_succeeded); + count_vm_events(PGMIGRATE_FAIL, stats.nr_failed_pages); + count_vm_events(THP_MIGRATION_SUCCESS, stats.nr_thp_succeeded); + count_vm_events(THP_MIGRATION_FAIL, stats.nr_thp_failed); + count_vm_events(THP_MIGRATION_SPLIT, stats.nr_thp_split); + trace_mm_migrate_pages(stats.nr_succeeded, stats.nr_failed_pages, + stats.nr_thp_succeeded, stats.nr_thp_failed, + stats.nr_thp_split, mode, reason); if (ret_succeeded) - *ret_succeeded = nr_succeeded; + *ret_succeeded = stats.nr_succeeded; return rc; } From 965a41cea72c8c27ce677f13a7bd308ea12d85b9 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:37 +0800 Subject: [PATCH 53/80] migrate_pages: separate hugetlb folios migration This is a preparation patch to batch the folio unmapping and moving for the non-hugetlb folios. Based on that we can batch the TLB shootdown during the folio migration and make it possible to use some hardware accelerator for the folio copying. In this patch the hugetlb folios and non-hugetlb folios migration is separated in migrate_pages() to make it easy to change the non-hugetlb folios migration implementation. Link: https://lkml.kernel.org/r/20230213123444.155149-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Reviewed-by: Xin Hao Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 141 +++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 119 insertions(+), 22 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 814c2187d5a40..f103f4565dbaf 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1416,6 +1416,8 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f return rc; } +#define NR_MAX_MIGRATE_PAGES_RETRY 10 + struct migrate_pages_stats { int nr_succeeded; /* Normal and large folios migrated successfully, in units of base pages */ @@ -1426,6 +1428,95 @@ struct migrate_pages_stats { int nr_thp_split; /* THP split before migrating */ }; +/* + * Returns the number of hugetlb folios that were not migrated, or an error code + * after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no hugetlb folios are movable + * any more because the list has become empty or no retryable hugetlb folios + * exist any more. It is caller's responsibility to call putback_movable_pages() + * only if ret != 0. + */ +static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, + free_page_t put_new_page, unsigned long private, + enum migrate_mode mode, int reason, + struct migrate_pages_stats *stats, + struct list_head *ret_folios) +{ + int retry = 1; + int nr_failed = 0; + int nr_retry_pages = 0; + int pass = 0; + struct folio *folio, *folio2; + int rc, nr_pages; + + for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && retry; pass++) { + retry = 0; + nr_retry_pages = 0; + + list_for_each_entry_safe(folio, folio2, from, lru) { + if (!folio_test_hugetlb(folio)) + continue; + + nr_pages = folio_nr_pages(folio); + + cond_resched(); + + rc = unmap_and_move_huge_page(get_new_page, + put_new_page, private, + &folio->page, pass > 2, mode, + reason, ret_folios); + /* + * The rules are: + * Success: hugetlb folio will be put back + * -EAGAIN: stay on the from list + * -ENOMEM: stay on the from list + * -ENOSYS: stay on the from list + * Other errno: put on ret_folios list + */ + switch(rc) { + case -ENOSYS: + /* Hugetlb migration is unsupported */ + nr_failed++; + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); + break; + case -ENOMEM: + /* + * When memory is low, don't bother to try to migrate + * other folios, just exit. + */ + stats->nr_failed_pages += nr_pages + nr_retry_pages; + return -ENOMEM; + case -EAGAIN: + retry++; + nr_retry_pages += nr_pages; + break; + case MIGRATEPAGE_SUCCESS: + stats->nr_succeeded += nr_pages; + break; + default: + /* + * Permanent failure (-EBUSY, etc.): + * unlike -EAGAIN case, the failed folio is + * removed from migration folio list and not + * retried in the next outer loop. + */ + nr_failed++; + stats->nr_failed_pages += nr_pages; + break; + } + } + } + /* + * nr_failed is number of hugetlb folios failed to be migrated. After + * NR_MAX_MIGRATE_PAGES_RETRY attempts, give up and count retried hugetlb + * folios as failed. + */ + nr_failed += retry; + stats->nr_failed_pages += nr_retry_pages; + + return nr_failed; +} + /* * migrate_pages - migrate the folios specified in a list, to the free folios * supplied as the target for the page migration @@ -1442,10 +1533,10 @@ struct migrate_pages_stats { * @ret_succeeded: Set to the number of folios migrated successfully if * the caller passes a non-NULL pointer. * - * The function returns after 10 attempts or if no folios are movable any more - * because the list has become empty or no retryable folios exist any more. - * It is caller's responsibility to call putback_movable_pages() to return folios - * to the LRU or free list only if ret != 0. + * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios + * are movable any more because the list has become empty or no retryable folios + * exist any more. It is caller's responsibility to call putback_movable_pages() + * only if ret != 0. * * Returns the number of {normal folio, large folio, hugetlb} that were not * migrated, or an error code. The number of large folio splits will be @@ -1459,7 +1550,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, int retry = 1; int large_retry = 1; int thp_retry = 1; - int nr_failed = 0; + int nr_failed; int nr_retry_pages = 0; int nr_large_failed = 0; int pass = 0; @@ -1476,38 +1567,45 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, trace_mm_migrate_pages_start(mode, reason); memset(&stats, 0, sizeof(stats)); + rc = migrate_hugetlbs(from, get_new_page, put_new_page, private, mode, reason, + &stats, &ret_folios); + if (rc < 0) + goto out; + nr_failed = rc; + split_folio_migration: - for (pass = 0; pass < 10 && (retry || large_retry); pass++) { + for (pass = 0; + pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); + pass++) { retry = 0; large_retry = 0; thp_retry = 0; nr_retry_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { + /* Retried hugetlb folios will be kept in list */ + if (folio_test_hugetlb(folio)) { + list_move_tail(&folio->lru, &ret_folios); + continue; + } + /* * Large folio statistics is based on the source large * folio. Capture required information that might get * lost during migration. */ - is_large = folio_test_large(folio) && !folio_test_hugetlb(folio); + is_large = folio_test_large(folio); is_thp = is_large && folio_test_pmd_mappable(folio); nr_pages = folio_nr_pages(folio); + cond_resched(); - if (folio_test_hugetlb(folio)) - rc = unmap_and_move_huge_page(get_new_page, - put_new_page, private, - &folio->page, pass > 2, mode, - reason, - &ret_folios); - else - rc = unmap_and_move(get_new_page, put_new_page, - private, folio, pass > 2, mode, - reason, &ret_folios); + rc = unmap_and_move(get_new_page, put_new_page, + private, folio, pass > 2, mode, + reason, &ret_folios); /* * The rules are: - * Success: non hugetlb folio will be freed, hugetlb - * folio will be put back + * Success: folio will be freed * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list * -ENOSYS: stay on the from list @@ -1534,7 +1632,6 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, stats.nr_thp_split += is_thp; break; } - /* Hugetlb migration is unsupported */ } else if (!no_split_folio_counting) { nr_failed++; } @@ -1628,8 +1725,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ if (!list_empty(&split_folios)) { /* - * Move non-migrated folios (after 10 retries) to ret_folios - * to avoid migrating them again. + * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY + * retries) to ret_folios to avoid migrating them again. */ list_splice_init(from, &ret_folios); list_splice_init(&split_folios, from); From f547d2bbe9e4fe447e2aec9e30cdf775270e289a Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:38 +0800 Subject: [PATCH 54/80] migrate_pages: restrict number of pages to migrate in batch This is a preparation patch to batch the folio unmapping and moving for non-hugetlb folios. If we had batched the folio unmapping, all folios to be migrated would be unmapped before copying the contents and flags of the folios. If the folios that were passed to migrate_pages() were too many in unit of pages, the execution of the processes would be stopped for too long time, thus too long latency. For example, migrate_pages() syscall will call migrate_pages() with all folios of a process. To avoid this possible issue, in this patch, we restrict the number of pages to be migrated to be no more than HPAGE_PMD_NR. That is, the influence is at the same level of THP migration. Link: https://lkml.kernel.org/r/20230213123444.155149-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 174 +++++++++++++++++++++++++++++++-------------------- 1 file changed, 106 insertions(+), 68 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index f103f4565dbaf..c3035bc25bed1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1416,6 +1416,11 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f return rc; } +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define NR_MAX_BATCHED_MIGRATION HPAGE_PMD_NR +#else +#define NR_MAX_BATCHED_MIGRATION 512 +#endif #define NR_MAX_MIGRATE_PAGES_RETRY 10 struct migrate_pages_stats { @@ -1517,40 +1522,15 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, return nr_failed; } -/* - * migrate_pages - migrate the folios specified in a list, to the free folios - * supplied as the target for the page migration - * - * @from: The list of folios to be migrated. - * @get_new_page: The function used to allocate free folios to be used - * as the target of the folio migration. - * @put_new_page: The function used to free target folios if migration - * fails, or NULL if no special handling is necessary. - * @private: Private data to be passed on to get_new_page() - * @mode: The migration mode that specifies the constraints for - * folio migration, if any. - * @reason: The reason for folio migration. - * @ret_succeeded: Set to the number of folios migrated successfully if - * the caller passes a non-NULL pointer. - * - * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios - * are movable any more because the list has become empty or no retryable folios - * exist any more. It is caller's responsibility to call putback_movable_pages() - * only if ret != 0. - * - * Returns the number of {normal folio, large folio, hugetlb} that were not - * migrated, or an error code. The number of large folio splits will be - * considered as the number of non-migrated large folio, no matter how many - * split folios of the large folio are migrated successfully. - */ -int migrate_pages(struct list_head *from, new_page_t get_new_page, +static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, free_page_t put_new_page, unsigned long private, - enum migrate_mode mode, int reason, unsigned int *ret_succeeded) + enum migrate_mode mode, int reason, struct list_head *ret_folios, + struct migrate_pages_stats *stats) { int retry = 1; int large_retry = 1; int thp_retry = 1; - int nr_failed; + int nr_failed = 0; int nr_retry_pages = 0; int nr_large_failed = 0; int pass = 0; @@ -1558,20 +1538,9 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, bool is_thp = false; struct folio *folio, *folio2; int rc, nr_pages; - LIST_HEAD(ret_folios); LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_split_folio_counting = false; - struct migrate_pages_stats stats; - - trace_mm_migrate_pages_start(mode, reason); - - memset(&stats, 0, sizeof(stats)); - rc = migrate_hugetlbs(from, get_new_page, put_new_page, private, mode, reason, - &stats, &ret_folios); - if (rc < 0) - goto out; - nr_failed = rc; split_folio_migration: for (pass = 0; @@ -1583,12 +1552,6 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, nr_retry_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { - /* Retried hugetlb folios will be kept in list */ - if (folio_test_hugetlb(folio)) { - list_move_tail(&folio->lru, &ret_folios); - continue; - } - /* * Large folio statistics is based on the source large * folio. Capture required information that might get @@ -1602,15 +1565,14 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, rc = unmap_and_move(get_new_page, put_new_page, private, folio, pass > 2, mode, - reason, &ret_folios); + reason, ret_folios); /* * The rules are: * Success: folio will be freed * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list * -ENOSYS: stay on the from list - * Other errno: put on ret_folios list then splice to - * from list + * Other errno: put on ret_folios list */ switch(rc) { /* @@ -1627,17 +1589,17 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, /* Large folio migration is unsupported */ if (is_large) { nr_large_failed++; - stats.nr_thp_failed += is_thp; + stats->nr_thp_failed += is_thp; if (!try_split_folio(folio, &split_folios)) { - stats.nr_thp_split += is_thp; + stats->nr_thp_split += is_thp; break; } } else if (!no_split_folio_counting) { nr_failed++; } - stats.nr_failed_pages += nr_pages; - list_move_tail(&folio->lru, &ret_folios); + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); break; case -ENOMEM: /* @@ -1646,13 +1608,13 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ if (is_large) { nr_large_failed++; - stats.nr_thp_failed += is_thp; + stats->nr_thp_failed += is_thp; /* Large folio NUMA faulting doesn't split to retry. */ if (!nosplit) { int ret = try_split_folio(folio, &split_folios); if (!ret) { - stats.nr_thp_split += is_thp; + stats->nr_thp_split += is_thp; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1670,17 +1632,17 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, nr_failed++; } - stats.nr_failed_pages += nr_pages + nr_retry_pages; + stats->nr_failed_pages += nr_pages + nr_retry_pages; /* * There might be some split folios of fail-to-migrate large - * folios left in split_folios list. Move them back to migration + * folios left in split_folios list. Move them to ret_folios * list so that they could be put back to the right list by * the caller otherwise the folio refcnt will be leaked. */ - list_splice_init(&split_folios, from); + list_splice_init(&split_folios, ret_folios); /* nr_failed isn't updated for not used */ nr_large_failed += large_retry; - stats.nr_thp_failed += thp_retry; + stats->nr_thp_failed += thp_retry; goto out; case -EAGAIN: if (is_large) { @@ -1692,8 +1654,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, nr_retry_pages += nr_pages; break; case MIGRATEPAGE_SUCCESS: - stats.nr_succeeded += nr_pages; - stats.nr_thp_succeeded += is_thp; + stats->nr_succeeded += nr_pages; + stats->nr_thp_succeeded += is_thp; break; default: /* @@ -1704,20 +1666,20 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, */ if (is_large) { nr_large_failed++; - stats.nr_thp_failed += is_thp; + stats->nr_thp_failed += is_thp; } else if (!no_split_folio_counting) { nr_failed++; } - stats.nr_failed_pages += nr_pages; + stats->nr_failed_pages += nr_pages; break; } } } nr_failed += retry; nr_large_failed += large_retry; - stats.nr_thp_failed += thp_retry; - stats.nr_failed_pages += nr_retry_pages; + stats->nr_thp_failed += thp_retry; + stats->nr_failed_pages += nr_retry_pages; /* * Try to migrate split folios of fail-to-migrate large folios, no * nr_failed counting in this round, since all split folios of a @@ -1728,7 +1690,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY * retries) to ret_folios to avoid migrating them again. */ - list_splice_init(from, &ret_folios); + list_splice_init(from, ret_folios); list_splice_init(&split_folios, from); no_split_folio_counting = true; retry = 1; @@ -1736,6 +1698,82 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, } rc = nr_failed + nr_large_failed; +out: + return rc; +} + +/* + * migrate_pages - migrate the folios specified in a list, to the free folios + * supplied as the target for the page migration + * + * @from: The list of folios to be migrated. + * @get_new_page: The function used to allocate free folios to be used + * as the target of the folio migration. + * @put_new_page: The function used to free target folios if migration + * fails, or NULL if no special handling is necessary. + * @private: Private data to be passed on to get_new_page() + * @mode: The migration mode that specifies the constraints for + * folio migration, if any. + * @reason: The reason for folio migration. + * @ret_succeeded: Set to the number of folios migrated successfully if + * the caller passes a non-NULL pointer. + * + * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios + * are movable any more because the list has become empty or no retryable folios + * exist any more. It is caller's responsibility to call putback_movable_pages() + * only if ret != 0. + * + * Returns the number of {normal folio, large folio, hugetlb} that were not + * migrated, or an error code. The number of large folio splits will be + * considered as the number of non-migrated large folio, no matter how many + * split folios of the large folio are migrated successfully. + */ +int migrate_pages(struct list_head *from, new_page_t get_new_page, + free_page_t put_new_page, unsigned long private, + enum migrate_mode mode, int reason, unsigned int *ret_succeeded) +{ + int rc, rc_gather; + int nr_pages; + struct folio *folio, *folio2; + LIST_HEAD(folios); + LIST_HEAD(ret_folios); + struct migrate_pages_stats stats; + + trace_mm_migrate_pages_start(mode, reason); + + memset(&stats, 0, sizeof(stats)); + + rc_gather = migrate_hugetlbs(from, get_new_page, put_new_page, private, + mode, reason, &stats, &ret_folios); + if (rc_gather < 0) + goto out; +again: + nr_pages = 0; + list_for_each_entry_safe(folio, folio2, from, lru) { + /* Retried hugetlb folios will be kept in list */ + if (folio_test_hugetlb(folio)) { + list_move_tail(&folio->lru, &ret_folios); + continue; + } + + nr_pages += folio_nr_pages(folio); + if (nr_pages > NR_MAX_BATCHED_MIGRATION) + break; + } + if (nr_pages > NR_MAX_BATCHED_MIGRATION) + list_cut_before(&folios, from, &folio->lru); + else + list_splice_init(from, &folios); + rc = migrate_pages_batch(&folios, get_new_page, put_new_page, private, + mode, reason, &ret_folios, &stats); + list_splice_tail_init(&folios, &ret_folios); + if (rc < 0) { + rc_gather = rc; + goto out; + } + rc_gather += rc; + if (!list_empty(from)) + goto again; out: /* * Put the permanent failure folio back to migration list, they @@ -1748,7 +1786,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, * are migrated successfully. */ if (list_empty(from)) - rc = 0; + rc_gather = 0; count_vm_events(PGMIGRATE_SUCCESS, stats.nr_succeeded); count_vm_events(PGMIGRATE_FAIL, stats.nr_failed_pages); @@ -1762,7 +1800,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, if (ret_succeeded) *ret_succeeded = stats.nr_succeeded; - return rc; + return rc_gather; } struct page *alloc_migration_target(struct page *page, unsigned long private) From 3df6b6d860d2dc7fb80a5f1dd3c6101df10b5882 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:39 +0800 Subject: [PATCH 55/80] migrate_pages: split unmap_and_move() to _unmap() and _move() This is a preparation patch to batch the folio unmapping and moving. In this patch, unmap_and_move() is split to migrate_folio_unmap() and migrate_folio_move(). So, we can batch _unmap() and _move() in different loops later. To pass some information between unmap and move, the original unused dst->mapping and dst->private are used. Link: https://lkml.kernel.org/r/20230213123444.155149-5-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Reviewed-by: Xin Hao Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- include/linux/migrate.h | 1 + mm/migrate.c | 169 ++++++++++++++++++++++++++++++---------- 2 files changed, 129 insertions(+), 41 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index bdff950a8bb45..c88b96b48be70 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -18,6 +18,7 @@ struct migration_target_control; * - zero on page migration success; */ #define MIGRATEPAGE_SUCCESS 0 +#define MIGRATEPAGE_UNMAP 1 /** * struct movable_operations - Driver page migration diff --git a/mm/migrate.c b/mm/migrate.c index c3035bc25bed1..59a9e1adc4989 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1029,11 +1029,53 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, return rc; } -static int __unmap_and_move(struct folio *src, struct folio *dst, +/* + * To record some information during migration, we use some unused + * fields (mapping and private) of struct folio of the newly allocated + * destination folio. This is safe because nobody is using them + * except us. + */ +static void __migrate_folio_record(struct folio *dst, + unsigned long page_was_mapped, + struct anon_vma *anon_vma) +{ + dst->mapping = (void *)anon_vma; + dst->private = (void *)page_was_mapped; +} + +static void __migrate_folio_extract(struct folio *dst, + int *page_was_mappedp, + struct anon_vma **anon_vmap) +{ + *anon_vmap = (void *)dst->mapping; + *page_was_mappedp = (unsigned long)dst->private; + dst->mapping = NULL; + dst->private = NULL; +} + +/* Cleanup src folio upon migration success */ +static void migrate_folio_done(struct folio *src, + enum migrate_reason reason) +{ + /* + * Compaction can migrate also non-LRU pages which are + * not accounted to NR_ISOLATED_*. They can be recognized + * as __PageMovable + */ + if (likely(!__folio_test_movable(src))) + mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + + folio_is_file_lru(src), -folio_nr_pages(src)); + + if (reason != MR_MEMORY_FAILURE) + /* We release the page in page_handle_poison. */ + folio_put(src); +} + +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, enum migrate_mode mode) { int rc = -EAGAIN; - bool page_was_mapped = false; + int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); @@ -1109,8 +1151,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, goto out_unlock; if (unlikely(!is_lru)) { - rc = move_to_new_folio(dst, src, mode); - goto out_unlock_both; + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; } /* @@ -1135,11 +1177,42 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); try_to_migrate(src, 0); - page_was_mapped = true; + page_was_mapped = 1; } - if (!folio_mapped(src)) - rc = move_to_new_folio(dst, src, mode); + if (!folio_mapped(src)) { + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; + } + + if (page_was_mapped) + remove_migration_ptes(src, src, false); + +out_unlock_both: + folio_unlock(dst); +out_unlock: + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); +out: + + return rc; +} + +static int __migrate_folio_move(struct folio *src, struct folio *dst, + enum migrate_mode mode) +{ + int rc; + int page_was_mapped = 0; + struct anon_vma *anon_vma = NULL; + bool is_lru = !__PageMovable(&src->page); + + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + + rc = move_to_new_folio(dst, src, mode); + if (unlikely(!is_lru)) + goto out_unlock_both; /* * When successful, push dst to LRU immediately: so that if it @@ -1162,12 +1235,10 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, out_unlock_both: folio_unlock(dst); -out_unlock: /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); folio_unlock(src); -out: /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased @@ -1179,19 +1250,15 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, return rc; } -/* - * Obtain the lock on folio, remove all ptes and migrate the folio - * to the newly allocated folio in dst. - */ -static int unmap_and_move(new_page_t get_new_page, - free_page_t put_new_page, - unsigned long private, struct folio *src, - int force, enum migrate_mode mode, - enum migrate_reason reason, - struct list_head *ret) +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { struct folio *dst; - int rc = MIGRATEPAGE_SUCCESS; + int rc = MIGRATEPAGE_UNMAP; struct page *newpage = NULL; if (!thp_migration_supported() && folio_test_transhuge(src)) @@ -1202,20 +1269,49 @@ static int unmap_and_move(new_page_t get_new_page, folio_clear_active(src); folio_clear_unevictable(src); /* free_pages_prepare() will clear PG_isolated. */ - goto out; + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; } newpage = get_new_page(&src->page, private); if (!newpage) return -ENOMEM; dst = page_folio(newpage); + *dstp = dst; dst->private = NULL; - rc = __unmap_and_move(src, dst, force, mode); + rc = __migrate_folio_unmap(src, dst, force, mode); + if (rc == MIGRATEPAGE_UNMAP) + return rc; + + /* + * A folio that has not been unmapped will be restored to + * right list unless we want to retry. + */ + if (rc != -EAGAIN) + list_move_tail(&src->lru, ret); + + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); + + return rc; +} + +/* Migrate the folio to the newly allocated folio in dst. */ +static int migrate_folio_move(free_page_t put_new_page, unsigned long private, + struct folio *src, struct folio *dst, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) +{ + int rc; + + rc = __migrate_folio_move(src, dst, mode); if (rc == MIGRATEPAGE_SUCCESS) set_page_owner_migrate_reason(&dst->page, reason); -out: if (rc != -EAGAIN) { /* * A folio that has been migrated has all references @@ -1231,20 +1327,7 @@ static int unmap_and_move(new_page_t get_new_page, * we want to retry. */ if (rc == MIGRATEPAGE_SUCCESS) { - /* - * Compaction can migrate also non-LRU folios which are - * not accounted to NR_ISOLATED_*. They can be recognized - * as __folio_test_movable - */ - if (likely(!__folio_test_movable(src))) - mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + - folio_is_file_lru(src), -folio_nr_pages(src)); - - if (reason != MR_MEMORY_FAILURE) - /* - * We release the folio in page_handle_poison. - */ - folio_put(src); + migrate_folio_done(src, reason); } else { if (rc != -EAGAIN) list_add_tail(&src->lru, ret); @@ -1536,7 +1619,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, int pass = 0; bool is_large = false; bool is_thp = false; - struct folio *folio, *folio2; + struct folio *folio, *folio2, *dst = NULL; int rc, nr_pages; LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); @@ -1563,9 +1646,13 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, cond_resched(); - rc = unmap_and_move(get_new_page, put_new_page, - private, folio, pass > 2, mode, - reason, ret_folios); + rc = migrate_folio_unmap(get_new_page, put_new_page, private, + folio, &dst, pass > 2, mode, + reason, ret_folios); + if (rc == MIGRATEPAGE_UNMAP) + rc = migrate_folio_move(put_new_page, private, + folio, dst, mode, + reason, ret_folios); /* * The rules are: * Success: folio will be freed From 6a0d8c9e627ea25e7347d505c410aa6d658a00dd Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:40 +0800 Subject: [PATCH 56/80] migrate_pages: batch _unmap and _move In this patch the _unmap and _move stage of the folio migration is batched. That for, previously, it is, for each folio _unmap() _move() Now, it is, for each folio _unmap() for each folio _move() Based on this, we can batch the TLB flushing and use some hardware accelerator to copy folios between batched _unmap and batched _move stages. Link: https://lkml.kernel.org/r/20230213123444.155149-6-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Signed-off-by: Andrew Morton --- mm/migrate.c | 214 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 189 insertions(+), 25 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 59a9e1adc4989..106b95f19fab3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1053,6 +1053,33 @@ static void __migrate_folio_extract(struct folio *dst, dst->private = NULL; } +/* Restore the source folio to the original state upon failure */ +static void migrate_folio_undo_src(struct folio *src, + int page_was_mapped, + struct anon_vma *anon_vma, + struct list_head *ret) +{ + if (page_was_mapped) + remove_migration_ptes(src, src, false); + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); + list_move_tail(&src->lru, ret); +} + +/* Restore the destination folio to the original state upon failure */ +static void migrate_folio_undo_dst(struct folio *dst, + free_page_t put_new_page, + unsigned long private) +{ + folio_unlock(dst); + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); +} + /* Cleanup src folio upon migration success */ static void migrate_folio_done(struct folio *src, enum migrate_reason reason) @@ -1071,8 +1098,8 @@ static void migrate_folio_done(struct folio *src, folio_put(src); } -static int __migrate_folio_unmap(struct folio *src, struct folio *dst, - int force, enum migrate_mode mode) +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, + bool avoid_force_lock, enum migrate_mode mode) { int rc = -EAGAIN; int page_was_mapped = 0; @@ -1099,6 +1126,17 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, if (current->flags & PF_MEMALLOC) goto out; + /* + * We have locked some folios and are going to wait to lock + * this folio. To avoid a potential deadlock, let's bail + * out and not do that. The locked folios will be moved and + * unlocked, then we can wait to lock this folio. + */ + if (avoid_force_lock) { + rc = -EDEADLOCK; + goto out; + } + folio_lock(src); } @@ -1207,10 +1245,20 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); + struct list_head *prev; __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + prev = dst->lru.prev; + list_del(&dst->lru); rc = move_to_new_folio(dst, src, mode); + + if (rc == -EAGAIN) { + list_add(&dst->lru, prev); + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return rc; + } + if (unlikely(!is_lru)) goto out_unlock_both; @@ -1253,7 +1301,7 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, /* Obtain the lock on page, remove all ptes. */ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, unsigned long private, struct folio *src, - struct folio **dstp, int force, + struct folio **dstp, int force, bool avoid_force_lock, enum migrate_mode mode, enum migrate_reason reason, struct list_head *ret) { @@ -1281,7 +1329,7 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page *dstp = dst; dst->private = NULL; - rc = __migrate_folio_unmap(src, dst, force, mode); + rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); if (rc == MIGRATEPAGE_UNMAP) return rc; @@ -1289,7 +1337,7 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page * A folio that has not been unmapped will be restored to * right list unless we want to retry. */ - if (rc != -EAGAIN) + if (rc != -EAGAIN && rc != -EDEADLOCK) list_move_tail(&src->lru, ret); if (put_new_page) @@ -1328,9 +1376,8 @@ static int migrate_folio_move(free_page_t put_new_page, unsigned long private, */ if (rc == MIGRATEPAGE_SUCCESS) { migrate_folio_done(src, reason); - } else { - if (rc != -EAGAIN) - list_add_tail(&src->lru, ret); + } else if (rc != -EAGAIN) { + list_add_tail(&src->lru, ret); if (put_new_page) put_new_page(&dst->page, private); @@ -1605,12 +1652,16 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, return nr_failed; } +/* + * migrate_pages_batch() first unmaps folios in the from list as many as + * possible, then move the unmapped folios. + */ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, free_page_t put_new_page, unsigned long private, enum migrate_mode mode, int reason, struct list_head *ret_folios, struct migrate_pages_stats *stats) { - int retry = 1; + int retry; int large_retry = 1; int thp_retry = 1; int nr_failed = 0; @@ -1619,13 +1670,19 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, int pass = 0; bool is_large = false; bool is_thp = false; - struct folio *folio, *folio2, *dst = NULL; - int rc, nr_pages; + struct folio *folio, *folio2, *dst = NULL, *dst2; + int rc, rc_saved, nr_pages; LIST_HEAD(split_folios); + LIST_HEAD(unmap_folios); + LIST_HEAD(dst_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_split_folio_counting = false; + bool avoid_force_lock; -split_folio_migration: +retry: + rc_saved = 0; + avoid_force_lock = false; + retry = 1; for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); pass++) { @@ -1647,16 +1704,15 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, cond_resched(); rc = migrate_folio_unmap(get_new_page, put_new_page, private, - folio, &dst, pass > 2, mode, - reason, ret_folios); - if (rc == MIGRATEPAGE_UNMAP) - rc = migrate_folio_move(put_new_page, private, - folio, dst, mode, - reason, ret_folios); + folio, &dst, pass > 2, avoid_force_lock, + mode, reason, ret_folios); /* * The rules are: * Success: folio will be freed + * Unmap: folio will be put on unmap_folios list, + * dst folio put on dst_folios list * -EAGAIN: stay on the from list + * -EDEADLOCK: stay on the from list * -ENOMEM: stay on the from list * -ENOSYS: stay on the from list * Other errno: put on ret_folios list @@ -1691,7 +1747,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, case -ENOMEM: /* * When memory is low, don't bother to try to migrate - * other folios, just exit. + * other folios, move unmapped folios, then exit. */ if (is_large) { nr_large_failed++; @@ -1730,7 +1786,19 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, /* nr_failed isn't updated for not used */ nr_large_failed += large_retry; stats->nr_thp_failed += thp_retry; - goto out; + rc_saved = rc; + if (list_empty(&unmap_folios)) + goto out; + else + goto move; + case -EDEADLOCK: + /* + * The folio cannot be locked for potential deadlock. + * Go move (and unlock) all locked folios. Then we can + * try again. + */ + rc_saved = rc; + goto move; case -EAGAIN: if (is_large) { large_retry++; @@ -1744,6 +1812,15 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, stats->nr_succeeded += nr_pages; stats->nr_thp_succeeded += is_thp; break; + case MIGRATEPAGE_UNMAP: + /* + * We have locked some folios, don't force lock + * to avoid deadlock. + */ + avoid_force_lock = true; + list_move_tail(&folio->lru, &unmap_folios); + list_add_tail(&dst->lru, &dst_folios); + break; default: /* * Permanent failure (-EBUSY, etc.): @@ -1767,12 +1844,95 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, nr_large_failed += large_retry; stats->nr_thp_failed += thp_retry; stats->nr_failed_pages += nr_retry_pages; +move: + retry = 1; + for (pass = 0; + pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); + pass++) { + retry = 0; + large_retry = 0; + thp_retry = 0; + nr_retry_pages = 0; + + dst = list_first_entry(&dst_folios, struct folio, lru); + dst2 = list_next_entry(dst, lru); + list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { + is_large = folio_test_large(folio); + is_thp = is_large && folio_test_pmd_mappable(folio); + nr_pages = folio_nr_pages(folio); + + cond_resched(); + + rc = migrate_folio_move(put_new_page, private, + folio, dst, mode, + reason, ret_folios); + /* + * The rules are: + * Success: folio will be freed + * -EAGAIN: stay on the unmap_folios list + * Other errno: put on ret_folios list + */ + switch(rc) { + case -EAGAIN: + if (is_large) { + large_retry++; + thp_retry += is_thp; + } else if (!no_split_folio_counting) { + retry++; + } + nr_retry_pages += nr_pages; + break; + case MIGRATEPAGE_SUCCESS: + stats->nr_succeeded += nr_pages; + stats->nr_thp_succeeded += is_thp; + break; + default: + if (is_large) { + nr_large_failed++; + stats->nr_thp_failed += is_thp; + } else if (!no_split_folio_counting) { + nr_failed++; + } + + stats->nr_failed_pages += nr_pages; + break; + } + dst = dst2; + dst2 = list_next_entry(dst, lru); + } + } + nr_failed += retry; + nr_large_failed += large_retry; + stats->nr_thp_failed += thp_retry; + stats->nr_failed_pages += nr_retry_pages; + + if (rc_saved) + rc = rc_saved; + else + rc = nr_failed + nr_large_failed; +out: + /* Cleanup remaining folios */ + dst = list_first_entry(&dst_folios, struct folio, lru); + dst2 = list_next_entry(dst, lru); + list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { + int page_was_mapped = 0; + struct anon_vma *anon_vma = NULL; + + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + migrate_folio_undo_src(folio, page_was_mapped, anon_vma, + ret_folios); + list_del(&dst->lru); + migrate_folio_undo_dst(dst, put_new_page, private); + dst = dst2; + dst2 = list_next_entry(dst, lru); + } + /* * Try to migrate split folios of fail-to-migrate large folios, no * nr_failed counting in this round, since all split folios of a * large folio is counted as 1 failure in the first round. */ - if (!list_empty(&split_folios)) { + if (rc >= 0 && !list_empty(&split_folios)) { /* * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY * retries) to ret_folios to avoid migrating them again. @@ -1780,12 +1940,16 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, list_splice_init(from, ret_folios); list_splice_init(&split_folios, from); no_split_folio_counting = true; - retry = 1; - goto split_folio_migration; + goto retry; } - rc = nr_failed + nr_large_failed; -out: + /* + * We have unlocked all locked folios, so we can force lock now, let's + * try again. + */ + if (rc == -EDEADLOCK) + goto retry; + return rc; } From 05acd76093e49ff617a59493986c97447875eed5 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:41 +0800 Subject: [PATCH 57/80] migrate_pages: move migrate_folio_unmap() Just move the position of the functions. There's no any functionality change. This is to make it easier to review the next patch via putting code near its position in the next patch. Link: https://lkml.kernel.org/r/20230213123444.155149-7-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 100 +++++++++++++++++++++++++-------------------------- 1 file changed, 50 insertions(+), 50 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 106b95f19fab3..0a77fecb4395e 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1238,6 +1238,56 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force return rc; } +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, bool avoid_force_lock, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) +{ + struct folio *dst; + int rc = MIGRATEPAGE_UNMAP; + struct page *newpage = NULL; + + if (!thp_migration_supported() && folio_test_transhuge(src)) + return -ENOSYS; + + if (folio_ref_count(src) == 1) { + /* Folio was freed from under us. So we are done. */ + folio_clear_active(src); + folio_clear_unevictable(src); + /* free_pages_prepare() will clear PG_isolated. */ + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; + } + + newpage = get_new_page(&src->page, private); + if (!newpage) + return -ENOMEM; + dst = page_folio(newpage); + *dstp = dst; + + dst->private = NULL; + rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); + if (rc == MIGRATEPAGE_UNMAP) + return rc; + + /* + * A folio that has not been unmapped will be restored to + * right list unless we want to retry. + */ + if (rc != -EAGAIN && rc != -EDEADLOCK) + list_move_tail(&src->lru, ret); + + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); + + return rc; +} + static int __migrate_folio_move(struct folio *src, struct folio *dst, enum migrate_mode mode) { @@ -1298,56 +1348,6 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, return rc; } -/* Obtain the lock on page, remove all ptes. */ -static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, - unsigned long private, struct folio *src, - struct folio **dstp, int force, bool avoid_force_lock, - enum migrate_mode mode, enum migrate_reason reason, - struct list_head *ret) -{ - struct folio *dst; - int rc = MIGRATEPAGE_UNMAP; - struct page *newpage = NULL; - - if (!thp_migration_supported() && folio_test_transhuge(src)) - return -ENOSYS; - - if (folio_ref_count(src) == 1) { - /* Folio was freed from under us. So we are done. */ - folio_clear_active(src); - folio_clear_unevictable(src); - /* free_pages_prepare() will clear PG_isolated. */ - list_del(&src->lru); - migrate_folio_done(src, reason); - return MIGRATEPAGE_SUCCESS; - } - - newpage = get_new_page(&src->page, private); - if (!newpage) - return -ENOMEM; - dst = page_folio(newpage); - *dstp = dst; - - dst->private = NULL; - rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); - if (rc == MIGRATEPAGE_UNMAP) - return rc; - - /* - * A folio that has not been unmapped will be restored to - * right list unless we want to retry. - */ - if (rc != -EAGAIN && rc != -EDEADLOCK) - list_move_tail(&src->lru, ret); - - if (put_new_page) - put_new_page(&dst->page, private); - else - folio_put(dst); - - return rc; -} - /* Migrate the folio to the newly allocated folio in dst. */ static int migrate_folio_move(free_page_t put_new_page, unsigned long private, struct folio *src, struct folio *dst, From c1614c236ad308578ba077ee5009a62dc141e887 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:42 +0800 Subject: [PATCH 58/80] migrate_pages: share more code between _unmap and _move This is a code cleanup patch to reduce the duplicated code between the _unmap and _move stages of migrate_pages(). No functionality change is expected. Link: https://lkml.kernel.org/r/20230213123444.155149-8-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 207 +++++++++++++++++++++------------------------------ 1 file changed, 85 insertions(+), 122 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 0a77fecb4395e..ae94979e3209d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1057,6 +1057,7 @@ static void __migrate_folio_extract(struct folio *dst, static void migrate_folio_undo_src(struct folio *src, int page_was_mapped, struct anon_vma *anon_vma, + bool locked, struct list_head *ret) { if (page_was_mapped) @@ -1064,16 +1065,20 @@ static void migrate_folio_undo_src(struct folio *src, /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); - folio_unlock(src); - list_move_tail(&src->lru, ret); + if (locked) + folio_unlock(src); + if (ret) + list_move_tail(&src->lru, ret); } /* Restore the destination folio to the original state upon failure */ static void migrate_folio_undo_dst(struct folio *dst, + bool locked, free_page_t put_new_page, unsigned long private) { - folio_unlock(dst); + if (locked) + folio_unlock(dst); if (put_new_page) put_new_page(&dst->page, private); else @@ -1098,13 +1103,42 @@ static void migrate_folio_done(struct folio *src, folio_put(src); } -static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, - bool avoid_force_lock, enum migrate_mode mode) +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, bool avoid_force_lock, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { + struct folio *dst; int rc = -EAGAIN; + struct page *newpage = NULL; int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); + bool locked = false; + bool dst_locked = false; + + if (!thp_migration_supported() && folio_test_transhuge(src)) + return -ENOSYS; + + if (folio_ref_count(src) == 1) { + /* Folio was freed from under us. So we are done. */ + folio_clear_active(src); + folio_clear_unevictable(src); + /* free_pages_prepare() will clear PG_isolated. */ + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; + } + + newpage = get_new_page(&src->page, private); + if (!newpage) + return -ENOMEM; + dst = page_folio(newpage); + *dstp = dst; + + dst->private = NULL; if (!folio_trylock(src)) { if (!force || mode == MIGRATE_ASYNC) @@ -1139,6 +1173,7 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force folio_lock(src); } + locked = true; if (folio_test_writeback(src)) { /* @@ -1153,10 +1188,10 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force break; default: rc = -EBUSY; - goto out_unlock; + goto out; } if (!force) - goto out_unlock; + goto out; folio_wait_writeback(src); } @@ -1186,7 +1221,8 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force * This is much like races on refcount of oldpage: just don't BUG(). */ if (unlikely(!folio_trylock(dst))) - goto out_unlock; + goto out; + dst_locked = true; if (unlikely(!is_lru)) { __migrate_folio_record(dst, page_was_mapped, anon_vma); @@ -1208,7 +1244,7 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force if (!src->mapping) { if (folio_test_private(src)) { try_to_free_buffers(src); - goto out_unlock_both; + goto out; } } else if (folio_mapped(src)) { /* Establish migration ptes */ @@ -1223,73 +1259,25 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force return MIGRATEPAGE_UNMAP; } - if (page_was_mapped) - remove_migration_ptes(src, src, false); - -out_unlock_both: - folio_unlock(dst); -out_unlock: - /* Drop an anon_vma reference if we took one */ - if (anon_vma) - put_anon_vma(anon_vma); - folio_unlock(src); out: - - return rc; -} - -/* Obtain the lock on page, remove all ptes. */ -static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, - unsigned long private, struct folio *src, - struct folio **dstp, int force, bool avoid_force_lock, - enum migrate_mode mode, enum migrate_reason reason, - struct list_head *ret) -{ - struct folio *dst; - int rc = MIGRATEPAGE_UNMAP; - struct page *newpage = NULL; - - if (!thp_migration_supported() && folio_test_transhuge(src)) - return -ENOSYS; - - if (folio_ref_count(src) == 1) { - /* Folio was freed from under us. So we are done. */ - folio_clear_active(src); - folio_clear_unevictable(src); - /* free_pages_prepare() will clear PG_isolated. */ - list_del(&src->lru); - migrate_folio_done(src, reason); - return MIGRATEPAGE_SUCCESS; - } - - newpage = get_new_page(&src->page, private); - if (!newpage) - return -ENOMEM; - dst = page_folio(newpage); - *dstp = dst; - - dst->private = NULL; - rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); - if (rc == MIGRATEPAGE_UNMAP) - return rc; - /* * A folio that has not been unmapped will be restored to * right list unless we want to retry. */ - if (rc != -EAGAIN && rc != -EDEADLOCK) - list_move_tail(&src->lru, ret); + if (rc == -EAGAIN || rc == -EDEADLOCK) + ret = NULL; - if (put_new_page) - put_new_page(&dst->page, private); - else - folio_put(dst); + migrate_folio_undo_src(src, page_was_mapped, anon_vma, locked, ret); + migrate_folio_undo_dst(dst, dst_locked, put_new_page, private); return rc; } -static int __migrate_folio_move(struct folio *src, struct folio *dst, - enum migrate_mode mode) +/* Migrate the folio to the newly allocated folio in dst. */ +static int migrate_folio_move(free_page_t put_new_page, unsigned long private, + struct folio *src, struct folio *dst, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { int rc; int page_was_mapped = 0; @@ -1302,12 +1290,8 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, list_del(&dst->lru); rc = move_to_new_folio(dst, src, mode); - - if (rc == -EAGAIN) { - list_add(&dst->lru, prev); - __migrate_folio_record(dst, page_was_mapped, anon_vma); - return rc; - } + if (rc) + goto out; if (unlikely(!is_lru)) goto out_unlock_both; @@ -1321,70 +1305,49 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, * unsuccessful, and other cases when a page has been temporarily * isolated from the unevictable LRU: but this case is the easiest. */ - if (rc == MIGRATEPAGE_SUCCESS) { - folio_add_lru(dst); - if (page_was_mapped) - lru_add_drain(); - } + folio_add_lru(dst); + if (page_was_mapped) + lru_add_drain(); if (page_was_mapped) - remove_migration_ptes(src, - rc == MIGRATEPAGE_SUCCESS ? dst : src, false); + remove_migration_ptes(src, dst, false); out_unlock_both: folio_unlock(dst); - /* Drop an anon_vma reference if we took one */ - if (anon_vma) - put_anon_vma(anon_vma); - folio_unlock(src); + set_page_owner_migrate_reason(&dst->page, reason); /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased * refcounter. */ - if (rc == MIGRATEPAGE_SUCCESS) - folio_put(dst); - - return rc; -} - -/* Migrate the folio to the newly allocated folio in dst. */ -static int migrate_folio_move(free_page_t put_new_page, unsigned long private, - struct folio *src, struct folio *dst, - enum migrate_mode mode, enum migrate_reason reason, - struct list_head *ret) -{ - int rc; - - rc = __migrate_folio_move(src, dst, mode); - if (rc == MIGRATEPAGE_SUCCESS) - set_page_owner_migrate_reason(&dst->page, reason); - - if (rc != -EAGAIN) { - /* - * A folio that has been migrated has all references - * removed and will be freed. A folio that has not been - * migrated will have kept its references and be restored. - */ - list_del(&src->lru); - } + folio_put(dst); /* - * If migration is successful, releases reference grabbed during - * isolation. Otherwise, restore the folio to right list unless - * we want to retry. + * A folio that has been migrated has all references removed + * and will be freed. */ - if (rc == MIGRATEPAGE_SUCCESS) { - migrate_folio_done(src, reason); - } else if (rc != -EAGAIN) { - list_add_tail(&src->lru, ret); + list_del(&src->lru); + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); + migrate_folio_done(src, reason); - if (put_new_page) - put_new_page(&dst->page, private); - else - folio_put(dst); + return rc; +out: + /* + * A folio that has not been migrated will be restored to + * right list unless we want to retry. + */ + if (rc == -EAGAIN) { + list_add(&dst->lru, prev); + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return rc; } + migrate_folio_undo_src(src, page_was_mapped, anon_vma, true, ret); + migrate_folio_undo_dst(dst, true, put_new_page, private); + return rc; } @@ -1920,9 +1883,9 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); migrate_folio_undo_src(folio, page_was_mapped, anon_vma, - ret_folios); + true, ret_folios); list_del(&dst->lru); - migrate_folio_undo_dst(dst, put_new_page, private); + migrate_folio_undo_dst(dst, true, put_new_page, private); dst = dst2; dst2 = list_next_entry(dst, lru); } From aaf976760cb0cc758d276ef9c5c550b84e097c2a Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:43 +0800 Subject: [PATCH 59/80] migrate_pages: batch flushing TLB The TLB flushing will cost quite some CPU cycles during the folio migration in some situations. For example, when migrate a folio of a process with multiple active threads that run on multiple CPUs. After batching the _unmap and _move in migrate_pages(), the TLB flushing can be batched easily with the existing TLB flush batching mechanism. This patch implements that. We use the following test case to test the patch. On a 2-socket Intel server, - Run pmbench memory accessing benchmark - Run `migratepages` to migrate pages of pmbench between node 0 and node 1 back and forth. With the patch, the TLB flushing IPI reduces 99.1% during the test and the number of pages migrated successfully per second increases 291.7%. Haoxin helped to test the patchset on an ARM64 server with 128 cores, 2 NUMA nodes. Test results show that the page migration performance increases up to 78%. NOTE: TLB flushing is batched only for normal folios, not for THP folios. Because the overhead of TLB flushing for THP folios is much lower than that for normal folios (about 1/512 on x86 platform). Link: https://lkml.kernel.org/r/20230213123444.155149-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Xin Hao Reviewed-by: Zi Yan Reviewed-by: Xin Hao Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 5 ++++- mm/rmap.c | 20 +++++++++++++++++--- 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index ae94979e3209d..78d37ae4c3330 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1250,7 +1250,7 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page /* Establish migration ptes */ VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); - try_to_migrate(src, 0); + try_to_migrate(src, TTU_BATCH_FLUSH); page_was_mapped = 1; } @@ -1808,6 +1808,9 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, stats->nr_thp_failed += thp_retry; stats->nr_failed_pages += nr_retry_pages; move: + /* Flush TLBs for all unmapped folios */ + try_to_unmap_flush(); + retry = 1; for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); diff --git a/mm/rmap.c b/mm/rmap.c index 8287f2cc327d3..15ae24585fc49 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1952,7 +1952,21 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, } else { flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); /* Nuke the page table entry. */ - pteval = ptep_clear_flush(vma, address, pvmw.pte); + if (should_defer_flush(mm, flags)) { + /* + * We clear the PTE but do not flush so potentially + * a remote CPU could still be writing to the folio. + * If the entry was previously clean then the + * architecture must guarantee that a clear->dirty + * transition on a cached TLB entry is written through + * and traps if the PTE is unmapped. + */ + pteval = ptep_get_and_clear(mm, address, pvmw.pte); + + set_tlb_ubc_flush_pending(mm, pte_dirty(pteval)); + } else { + pteval = ptep_clear_flush(vma, address, pvmw.pte); + } } /* Set the dirty flag on the folio now the pte is gone. */ @@ -2124,10 +2138,10 @@ void try_to_migrate(struct folio *folio, enum ttu_flags flags) /* * Migration always ignores mlock and only supports TTU_RMAP_LOCKED and - * TTU_SPLIT_HUGE_PMD and TTU_SYNC flags. + * TTU_SPLIT_HUGE_PMD, TTU_SYNC, and TTU_BATCH_FLUSH flags. */ if (WARN_ON_ONCE(flags & ~(TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PMD | - TTU_SYNC))) + TTU_SYNC | TTU_BATCH_FLUSH))) return; if (folio_is_zone_device(folio) && From 2e839e7d744db2df8f29ccd63ba2a2ac526363ea Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:44 +0800 Subject: [PATCH 60/80] migrate_pages: move THP/hugetlb migration support check to simplify code This is a code cleanup patch, no functionality change is expected. After the change, the line number reduces especially in the long migrate_pages_batch(). Link: https://lkml.kernel.org/r/20230213123444.155149-10-ying.huang@intel.com Signed-off-by: "Huang, Ying" Suggested-by: Alistair Popple Reviewed-by: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 83 +++++++++++++++++++++++----------------------------- 1 file changed, 36 insertions(+), 47 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 78d37ae4c3330..40c63e77e91fb 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1119,9 +1119,6 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page bool locked = false; bool dst_locked = false; - if (!thp_migration_supported() && folio_test_transhuge(src)) - return -ENOSYS; - if (folio_ref_count(src) == 1) { /* Folio was freed from under us. So we are done. */ folio_clear_active(src); @@ -1382,16 +1379,6 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, struct anon_vma *anon_vma = NULL; struct address_space *mapping = NULL; - /* - * Migratability of hugepages depends on architectures and their size. - * This check is necessary because some callers of hugepage migration - * like soft offline and memory hotremove don't walk through page - * tables or check whether the hugepage is pmd-based or not before - * kicking migration. - */ - if (!hugepage_migration_supported(page_hstate(hpage))) - return -ENOSYS; - if (folio_ref_count(src) == 1) { /* page was freed from under us. So we are done. */ folio_putback_active_hugetlb(src); @@ -1558,6 +1545,20 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, cond_resched(); + /* + * Migratability of hugepages depends on architectures and + * their size. This check is necessary because some callers + * of hugepage migration like soft offline and memory + * hotremove don't walk through page tables or check whether + * the hugepage is pmd-based or not before kicking migration. + */ + if (!hugepage_migration_supported(folio_hstate(folio))) { + nr_failed++; + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); + continue; + } + rc = unmap_and_move_huge_page(get_new_page, put_new_page, private, &folio->page, pass > 2, mode, @@ -1567,16 +1568,9 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, * Success: hugetlb folio will be put back * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list - * -ENOSYS: stay on the from list * Other errno: put on ret_folios list */ switch(rc) { - case -ENOSYS: - /* Hugetlb migration is unsupported */ - nr_failed++; - stats->nr_failed_pages += nr_pages; - list_move_tail(&folio->lru, ret_folios); - break; case -ENOMEM: /* * When memory is low, don't bother to try to migrate @@ -1666,6 +1660,28 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, cond_resched(); + /* + * Large folio migration might be unsupported or + * the allocation might be failed so we should retry + * on the same folio with the large folio split + * to normal folios. + * + * Split folios are put in split_folios, and + * we will migrate them after the rest of the + * list is processed. + */ + if (!thp_migration_supported() && is_thp) { + nr_large_failed++; + stats->nr_thp_failed++; + if (!try_split_folio(folio, &split_folios)) { + stats->nr_thp_split++; + continue; + } + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); + continue; + } + rc = migrate_folio_unmap(get_new_page, put_new_page, private, folio, &dst, pass > 2, avoid_force_lock, mode, reason, ret_folios); @@ -1677,36 +1693,9 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, * -EAGAIN: stay on the from list * -EDEADLOCK: stay on the from list * -ENOMEM: stay on the from list - * -ENOSYS: stay on the from list * Other errno: put on ret_folios list */ switch(rc) { - /* - * Large folio migration might be unsupported or - * the allocation could've failed so we should retry - * on the same folio with the large folio split - * to normal folios. - * - * Split folios are put in split_folios, and - * we will migrate them after the rest of the - * list is processed. - */ - case -ENOSYS: - /* Large folio migration is unsupported */ - if (is_large) { - nr_large_failed++; - stats->nr_thp_failed += is_thp; - if (!try_split_folio(folio, &split_folios)) { - stats->nr_thp_split += is_thp; - break; - } - } else if (!no_split_folio_counting) { - nr_failed++; - } - - stats->nr_failed_pages += nr_pages; - list_move_tail(&folio->lru, ret_folios); - break; case -ENOMEM: /* * When memory is low, don't bother to try to migrate From 20e5a4b7b1a7e9081507c9a87fcc6c354692560b Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Mon, 13 Feb 2023 00:53:22 -0700 Subject: [PATCH 61/80] mm: multi-gen LRU: avoid futile retries Recall that the per-node memcg LRU has two generations and they alternate when the last memcg (of a given node) is moved from one to the other. Each generation is also sharded into multiple bins to improve scalability. A reclaimer starts with a random bin (in the old generation) and, if it fails, it will retry, i.e., to try the rest of the bins. If a reclaimer fails with the last memcg, it should move this memcg to the young generation first, which causes the generations to alternate, and then retry. Otherwise, the retries will be futile because all other bins are empty. Link: https://lkml.kernel.org/r/20230213075322.1416966-1-yuzhao@google.com Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: Yu Zhao Reported-by: T.J. Mercier Signed-off-by: Andrew Morton --- mm/vmscan.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index d4b9fd1ae0ed8..34535bbd4fe90 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -5356,18 +5356,20 @@ static int shrink_one(struct lruvec *lruvec, struct scan_control *sc) static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc) { + int op; int gen; int bin; int first_bin; struct lruvec *lruvec; struct lru_gen_folio *lrugen; + struct mem_cgroup *memcg; const struct hlist_nulls_node *pos; - int op = 0; - struct mem_cgroup *memcg = NULL; unsigned long nr_to_reclaim = get_nr_to_reclaim(sc); bin = first_bin = get_random_u32_below(MEMCG_NR_BINS); restart: + op = 0; + memcg = NULL; gen = get_memcg_gen(READ_ONCE(pgdat->memcg_lru.seq)); rcu_read_lock(); @@ -5391,14 +5393,22 @@ static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc) op = shrink_one(lruvec, sc); - if (sc->nr_reclaimed >= nr_to_reclaim) - goto success; - rcu_read_lock(); + + if (sc->nr_reclaimed >= nr_to_reclaim) + break; } rcu_read_unlock(); + if (op) + lru_gen_rotate_memcg(lruvec, op); + + mem_cgroup_put(memcg); + + if (sc->nr_reclaimed >= nr_to_reclaim) + return; + /* restart if raced with lru_gen_rotate_memcg() */ if (gen != get_nulls_value(pos)) goto restart; @@ -5407,11 +5417,6 @@ static void shrink_many(struct pglist_data *pgdat, struct scan_control *sc) bin = get_memcg_bin(bin + 1); if (bin != first_bin) goto restart; -success: - if (op) - lru_gen_rotate_memcg(lruvec, op); - - mem_cgroup_put(memcg); } static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc) From 438da906fb19ba4adcb5725f1eb96519576a4676 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Sun, 12 Feb 2023 19:10:27 +0800 Subject: [PATCH 62/80] mm: page_alloc: call panic() when memoryless node allocation fails In free_area_init(), we will continue to run after allocation of memoryless node pgdat fails. However, in the subsequent process (such as when initializing zonelist), the case that NODE_DATA(nid) is NULL is not handled, which will cause panic. Instead of this, it's better to call panic() directly when the memory allocation fails during system boot. Link: https://lkml.kernel.org/r/20230212111027.95520-1-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Signed-off-by: Andrew Morton --- mm/page_alloc.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 6721c0ba12f8b..010ae27b0aab3 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8422,11 +8422,9 @@ void __init free_area_init(unsigned long *max_zone_pfn) /* Allocator not initialized yet */ pgdat = arch_alloc_nodedata(nid); - if (!pgdat) { - pr_err("Cannot allocate %zuB for node %d.\n", - sizeof(*pgdat), nid); - continue; - } + if (!pgdat) + panic("Cannot allocate %zuB for node %d.\n", + sizeof(*pgdat), nid); arch_refresh_nodedata(nid, pgdat); free_area_init_memoryless_node(nid); From 16622f192f904af85d1384cbead79338dfcfae5b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 14 Feb 2023 11:30:24 +0100 Subject: [PATCH 63/80] maple_tree: reduce stack usage with gcc-9 and earlier gcc-10 changed the way inlining works to be less aggressive, but older versions run into an oversized stack frame warning whenever CONFIG_KASAN_STACK is enabled, as that forces variables from inlined callees to be non-overlapping: lib/maple_tree.c: In function 'mas_wr_bnode': lib/maple_tree.c:4320:1: error: the frame size of 1424 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] Change the annotations on mas_store_b_node() and mas_commit_b_node() to explicitly forbid inlining in this configuration, which is the same behavior that newer versions already have. Link: https://lkml.kernel.org/r/20230214103030.1051950-1-arnd@kernel.org Signed-off-by: Arnd Bergmann Reviewed-by: David Hildenbrand Reviewed-by: Liam R. Howlett Cc: Andrey Ryabinin Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Dmitry Vyukov Cc: Vincenzo Frascino Cc: Vernon Yang Signed-off-by: Andrew Morton --- lib/maple_tree.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 5e97031892590..646297cae5d16 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -146,6 +146,13 @@ struct maple_subtree_state { struct maple_big_node *bn; }; +#ifdef CONFIG_KASAN_STACK +/* Prevent mas_wr_bnode() from exceeding the stack frame limit */ +#define noinline_for_kasan noinline_for_stack +#else +#define noinline_for_kasan inline +#endif + /* Functions */ static inline struct maple_node *mt_alloc_one(gfp_t gfp) { @@ -2107,7 +2114,7 @@ static inline void mas_bulk_rebalance(struct ma_state *mas, unsigned char end, * * Return: The actual end of the data stored in @b_node */ -static inline void mas_store_b_node(struct ma_wr_state *wr_mas, +static noinline_for_kasan void mas_store_b_node(struct ma_wr_state *wr_mas, struct maple_big_node *b_node, unsigned char offset_end) { unsigned char slot; @@ -3579,7 +3586,7 @@ static inline bool mas_reuse_node(struct ma_wr_state *wr_mas, * @b_node: The maple big node * @end: The end of the data. */ -static inline int mas_commit_b_node(struct ma_wr_state *wr_mas, +static noinline_for_kasan int mas_commit_b_node(struct ma_wr_state *wr_mas, struct maple_big_node *b_node, unsigned char end) { struct maple_node *node; From d77ebe4bea39a7b3f7414c1056c4b10e98480627 Mon Sep 17 00:00:00 2001 From: Yafang Shao Date: Tue, 14 Feb 2023 15:35:49 +0000 Subject: [PATCH 64/80] mm: percpu: fix incorrect size in pcpu_obj_full_size() The extra space which is used to store the obj_cgroup membership is only valid when kmemcg is enabled. The kmemcg can be disabled via the kernel parameter "cgroup.memory=nokmem" at boot time. This helper is also used in non-memcg code, for example the tracepoint, so we should fix it. It was found by code review when I was implementing bpf memory usage[1]. No real issue happens in production environment. [1]. https://lwn.net/Articles/921991/ Link: https://lkml.kernel.org/r/20230214153549.12291-1-laoar.shao@gmail.com Signed-off-by: Yafang Shao Reviewed-by: Roman Gushchin Acked-by: Dennis Zhou Cc: Tejun Heo Cc: Christoph Lameter Cc: Vasily Averin Signed-off-by: Andrew Morton --- mm/percpu-internal.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/percpu-internal.h b/mm/percpu-internal.h index 70b1ea23f4d23..f9847c1319989 100644 --- a/mm/percpu-internal.h +++ b/mm/percpu-internal.h @@ -4,6 +4,7 @@ #include #include +#include /* * pcpu_block_md is the metadata block struct. @@ -118,14 +119,15 @@ static inline int pcpu_chunk_map_bits(struct pcpu_chunk *chunk) * @size: size of area to allocate in bytes * * For each accounted object there is an extra space which is used to store - * obj_cgroup membership. Charge it too. + * obj_cgroup membership if kmemcg is not disabled. Charge it too. */ static inline size_t pcpu_obj_full_size(size_t size) { size_t extra_size = 0; #ifdef CONFIG_MEMCG_KMEM - extra_size += size / PCPU_MIN_ALLOC_SIZE * sizeof(struct obj_cgroup *); + if (!mem_cgroup_kmem_disabled()) + extra_size += size / PCPU_MIN_ALLOC_SIZE * sizeof(struct obj_cgroup *); #endif return size * num_possible_cpus() + extra_size; From 6d018554abb626bfb965eb1c018524bd4b49b010 Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (IBM)" Date: Tue, 14 Feb 2023 16:07:28 +0200 Subject: [PATCH 65/80] m68k/nommu: add missing definition of ARCH_PFN_OFFSET Patch series "fixups for generic implementation of pfn_valid()". Guenter reported boot failures on m68k-nommu and sh caused by the switch to the generic implementation of pfn_valid(): https://lore.kernel.org/all/20230212173513.GA4052259@roeck-us.net https://lore.kernel.org/all/20230212161320.GA3784076@roeck-us.net These are small fixups that address the issues. This patch (of 2): On m68k/nommu RAM does not necessarily start at 0x0 and when it does not pfn_valid() uses a wrong offset into the memory map which causes silent boot failures. Define ARCH_PFN_OFFSET to make pfn_valid() use the correct offset. Link: https://lkml.kernel.org/r/20230214140729.1649961-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20230214140729.1649961-2-rppt@kernel.org Fixes: d82f07f06cf8 ("m68k: use asm-generic/memory_model.h for both MMU and !MMU") Reported-by: Guenter Roeck Signed-off-by: Mike Rapoport (IBM) Acked-by: Greg Ungerer Reviewed-by: David Hildenbrand Cc: Arnd Bergmann Cc: Geert Uytterhoeven Cc: Rich Felker Cc: Yoshinori Sato Cc: John Paul Adrian Glaubitz Signed-off-by: Andrew Morton --- arch/m68k/include/asm/page_no.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/m68k/include/asm/page_no.h b/arch/m68k/include/asm/page_no.h index 43ff6b109ebbb..060e4c0e76053 100644 --- a/arch/m68k/include/asm/page_no.h +++ b/arch/m68k/include/asm/page_no.h @@ -28,6 +28,8 @@ extern unsigned long memory_end; #define virt_addr_valid(kaddr) (((unsigned long)(kaddr) >= PAGE_OFFSET) && \ ((unsigned long)(kaddr) < memory_end)) +#define ARCH_PFN_OFFSET PHYS_PFN(PAGE_OFFSET_RAW) + #endif /* __ASSEMBLY__ */ #endif /* _M68K_PAGE_NO_H */ From a360d14cbb54c89512f9c205494cdba2e1692f7d Mon Sep 17 00:00:00 2001 From: "Mike Rapoport (IBM)" Date: Tue, 14 Feb 2023 16:07:29 +0200 Subject: [PATCH 66/80] sh: initialize max_mapnr sh never initializes max_mapnr which is used by the generic implementation of pfn_valid(). Initialize max_mapnr with set_max_mapnr() in sh::paging_init(). Link: https://lkml.kernel.org/r/20230214140729.1649961-3-rppt@kernel.org Fixes: e5080a967785 ("mm, arch: add generic implementation of pfn_valid() for FLATMEM") Reported-by: Guenter Roeck Signed-off-by: Mike Rapoport (IBM) Acked-by: John Paul Adrian Glaubitz Reviewed-by: David Hildenbrand Cc: Arnd Bergmann Cc: Geert Uytterhoeven Cc: Greg Ungerer Cc: Rich Felker Cc: Yoshinori Sato Signed-off-by: Andrew Morton --- arch/sh/mm/init.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c index 506784702430c..bf1b540553164 100644 --- a/arch/sh/mm/init.c +++ b/arch/sh/mm/init.c @@ -301,6 +301,7 @@ void __init paging_init(void) */ max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT; min_low_pfn = __MEMORY_START >> PAGE_SHIFT; + set_max_mapnr(max_low_pfn - min_low_pfn); nodes_clear(node_online_map); From 1f0b1b661a0ca797efaf82451ad5fce851867d6e Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Mon, 13 Feb 2023 11:29:22 -0800 Subject: [PATCH 67/80] mm: memcontrol: rename memcg_kmem_enabled() Currently there are two kmem-related helper functions with a confusing semantics: memcg_kmem_enabled() and mem_cgroup_kmem_disabled(). The problem is that an obvious expectation memcg_kmem_enabled() == !mem_cgroup_kmem_disabled(), can be false. mem_cgroup_kmem_disabled() is similar to mem_cgroup_disabled(): it returns true only if CONFIG_MEMCG_KMEM is not set or the kmem accounting is disabled using a boot time kernel option "cgroup.memory=nokmem". It never changes the value dynamically. memcg_kmem_enabled() is different: it always returns false until the first non-root memory cgroup will get online (assuming the kernel memory accounting is enabled). It's goal is to improve the performance on systems without the cgroupfs mounted/memory controller enabled or on the systems with only the root memory cgroup. To make things more obvious and avoid potential bugs, let's rename memcg_kmem_enabled() to memcg_kmem_online(). Link: https://lkml.kernel.org/r/20230213192922.1146370-1-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin Acked-by: Muchun Song Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Shakeel Butt Cc: Dennis Zhou Signed-off-by: Andrew Morton --- include/linux/memcontrol.h | 14 +++++++------- mm/memcontrol.c | 8 ++++---- mm/page_alloc.c | 8 ++++---- mm/percpu.c | 2 +- mm/slab.h | 10 +++++----- mm/vmscan.c | 2 +- 6 files changed, 22 insertions(+), 22 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 35478695cabf8..5567319027d18 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1776,24 +1776,24 @@ struct obj_cgroup *get_obj_cgroup_from_page(struct page *page); int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size); void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size); -extern struct static_key_false memcg_kmem_enabled_key; +extern struct static_key_false memcg_kmem_online_key; -static inline bool memcg_kmem_enabled(void) +static inline bool memcg_kmem_online(void) { - return static_branch_likely(&memcg_kmem_enabled_key); + return static_branch_likely(&memcg_kmem_online_key); } static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order) { - if (memcg_kmem_enabled()) + if (memcg_kmem_online()) return __memcg_kmem_charge_page(page, gfp, order); return 0; } static inline void memcg_kmem_uncharge_page(struct page *page, int order) { - if (memcg_kmem_enabled()) + if (memcg_kmem_online()) __memcg_kmem_uncharge_page(page, order); } @@ -1814,7 +1814,7 @@ static inline void count_objcg_event(struct obj_cgroup *objcg, { struct mem_cgroup *memcg; - if (!memcg_kmem_enabled()) + if (!memcg_kmem_online()) return; rcu_read_lock(); @@ -1854,7 +1854,7 @@ static inline struct obj_cgroup *get_obj_cgroup_from_page(struct page *page) return NULL; } -static inline bool memcg_kmem_enabled(void) +static inline bool memcg_kmem_online(void) { return false; } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 17335459d8dc7..3e3cdb9bed952 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -345,8 +345,8 @@ static void memcg_reparent_objcgs(struct mem_cgroup *memcg, * conditional to this static branch, we'll have to allow modules that does * kmem_cache_alloc and the such to see this symbol as well */ -DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key); -EXPORT_SYMBOL(memcg_kmem_enabled_key); +DEFINE_STATIC_KEY_FALSE(memcg_kmem_online_key); +EXPORT_SYMBOL(memcg_kmem_online_key); #endif /** @@ -3034,7 +3034,7 @@ struct obj_cgroup *get_obj_cgroup_from_page(struct page *page) { struct obj_cgroup *objcg; - if (!memcg_kmem_enabled()) + if (!memcg_kmem_online()) return NULL; if (PageMemcgKmem(page)) { @@ -3746,7 +3746,7 @@ static int memcg_online_kmem(struct mem_cgroup *memcg) objcg->memcg = memcg; rcu_assign_pointer(memcg->objcg, objcg); - static_branch_enable(&memcg_kmem_enabled_key); + static_branch_enable(&memcg_kmem_online_key); memcg->kmemcg_id = memcg->id.id; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 010ae27b0aab3..713643fd132b5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1410,7 +1410,7 @@ static __always_inline bool free_pages_prepare(struct page *page, * Do not let hwpoison pages hit pcplists/buddy * Untie memcg state and reset page's owner */ - if (memcg_kmem_enabled() && PageMemcgKmem(page)) + if (memcg_kmem_online() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); reset_page_owner(page, order); page_table_check_free(page, order); @@ -1441,7 +1441,7 @@ static __always_inline bool free_pages_prepare(struct page *page, } if (PageMappingFlags(page)) page->mapping = NULL; - if (memcg_kmem_enabled() && PageMemcgKmem(page)) + if (memcg_kmem_online() && PageMemcgKmem(page)) __memcg_kmem_uncharge_page(page, order); if (check_free && free_page_is_bad(page)) bad++; @@ -5446,7 +5446,7 @@ unsigned long __alloc_pages_bulk(gfp_t gfp, int preferred_nid, goto out; /* Bulk allocator does not support memcg accounting. */ - if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT)) + if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT)) goto failed; /* Use the single page allocator for one page. */ @@ -5618,7 +5618,7 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid, page = __alloc_pages_slowpath(alloc_gfp, order, &ac); out: - if (memcg_kmem_enabled() && (gfp & __GFP_ACCOUNT) && page && + if (memcg_kmem_online() && (gfp & __GFP_ACCOUNT) && page && unlikely(__memcg_kmem_charge_page(page, gfp, order) != 0)) { __free_pages(page, order); page = NULL; diff --git a/mm/percpu.c b/mm/percpu.c index acd78da0493b9..28e07ede46f66 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1625,7 +1625,7 @@ static bool pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp, { struct obj_cgroup *objcg; - if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT)) + if (!memcg_kmem_online() || !(gfp & __GFP_ACCOUNT)) return true; objcg = get_obj_cgroup_from_current(); diff --git a/mm/slab.h b/mm/slab.h index 63fb4c00d5293..43966aa5fadf3 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -494,7 +494,7 @@ static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, { struct obj_cgroup *objcg; - if (!memcg_kmem_enabled()) + if (!memcg_kmem_online()) return true; if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)) @@ -535,7 +535,7 @@ static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, unsigned long off; size_t i; - if (!memcg_kmem_enabled() || !objcg) + if (!memcg_kmem_online() || !objcg) return; for (i = 0; i < size; i++) { @@ -567,7 +567,7 @@ static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, struct obj_cgroup **objcgs; int i; - if (!memcg_kmem_enabled()) + if (!memcg_kmem_online()) return; objcgs = slab_objcgs(slab); @@ -649,7 +649,7 @@ static inline struct kmem_cache *virt_to_cache(const void *obj) static __always_inline void account_slab(struct slab *slab, int order, struct kmem_cache *s, gfp_t gfp) { - if (memcg_kmem_enabled() && (s->flags & SLAB_ACCOUNT)) + if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT)) memcg_alloc_slab_cgroups(slab, s, gfp, true); mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), @@ -659,7 +659,7 @@ static __always_inline void account_slab(struct slab *slab, int order, static __always_inline void unaccount_slab(struct slab *slab, int order, struct kmem_cache *s) { - if (memcg_kmem_enabled()) + if (memcg_kmem_online()) memcg_free_slab_cgroups(slab); mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), diff --git a/mm/vmscan.c b/mm/vmscan.c index 34535bbd4fe90..098c79129c426 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -915,7 +915,7 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid, } /* Call non-slab shrinkers even though kmem is disabled */ - if (!memcg_kmem_enabled() && + if (!memcg_kmem_online() && !(shrinker->flags & SHRINKER_NONSLAB)) continue; From bb1235e20cc0d5b6cb9cf47b36482075febe5c45 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 15 Feb 2023 14:00:56 +0100 Subject: [PATCH 68/80] kasan: mark addr_has_metadata __always_inline Patch series "objtool warning fixes", v2. These are three of the easier fixes for objtool warnings around kasan/kmsan/kcsan. I dropped one patch since Peter had come up with a better fix, and adjusted the changelog text based on feedback. This patch (of 3): When the compiler decides not to inline this function, objtool complains about incorrect UACCESS state: mm/kasan/generic.o: warning: objtool: __asan_load2+0x11: call to addr_has_metadata() with UACCESS enabled Link: https://lore.kernel.org/all/20230208164011.2287122-1-arnd@kernel.org/ Link: https://lkml.kernel.org/r/20230215130058.3836177-2-arnd@kernel.org Signed-off-by: Arnd Bergmann Acked-by: Peter Zijlstra (Intel) Reviewed-by: Marco Elver Reviewed-by: Andrey Konovalov Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Josh Poimboeuf Cc: Kuan-Ying Lee Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- mm/kasan/kasan.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 308fb70fd40a5..8fae87ab99cc5 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -297,7 +297,7 @@ static inline const void *kasan_shadow_to_mem(const void *shadow_addr) << KASAN_SHADOW_SCALE_SHIFT); } -static inline bool addr_has_metadata(const void *addr) +static __always_inline bool addr_has_metadata(const void *addr) { return (kasan_reset_tag(addr) >= kasan_shadow_to_mem((void *)KASAN_SHADOW_START)); @@ -316,7 +316,7 @@ bool kasan_check_range(unsigned long addr, size_t size, bool write, #else /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ -static inline bool addr_has_metadata(const void *addr) +static __always_inline bool addr_has_metadata(const void *addr) { return (is_vmalloc_addr(addr) || virt_addr_valid(addr)); } From dfbeab8eedaf655fbb15b321a8afc82b46ffee8b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 15 Feb 2023 14:00:57 +0100 Subject: [PATCH 69/80] kmsan: disable ftrace in kmsan core code objtool warns about some suspicous code inside of kmsan: vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_n+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_n+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_1+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_1+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_2+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_2+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_4+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_4+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_8+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_8+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_instrument_asm_store+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_chain_origin+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_poison_alloca+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_warning+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: __msan_get_context_state+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: kmsan_copy_to_user+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: kmsan_unpoison_memory+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: kmsan_unpoison_entry_regs+0x4: call to __fentry__() with UACCESS enabled vmlinux.o: warning: objtool: kmsan_report+0x4: call to __fentry__() with UACCESS enabled The Makefile contained a line to turn off ftrace for the entire directory, but this does not work. Replace it with individual lines, matching the approach in kasan. Link: https://lkml.kernel.org/r/20230215130058.3836177-3-arnd@kernel.org Signed-off-by: Arnd Bergmann Fixes: f80be4571b19 ("kmsan: add KMSAN runtime core") Acked-by: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Josh Poimboeuf Cc: Kuan-Ying Lee Cc: Marco Elver Cc: Peter Zijlstra (Intel) Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- mm/kmsan/Makefile | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile index 98eab2856626f..91cfdde642d16 100644 --- a/mm/kmsan/Makefile +++ b/mm/kmsan/Makefile @@ -14,7 +14,13 @@ CC_FLAGS_KMSAN_RUNTIME := -fno-stack-protector CC_FLAGS_KMSAN_RUNTIME += $(call cc-option,-fno-conserve-stack) CC_FLAGS_KMSAN_RUNTIME += -DDISABLE_BRANCH_PROFILING -CFLAGS_REMOVE.o = $(CC_FLAGS_FTRACE) +# Disable ftrace to avoid recursion. +CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_hooks.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_instrumentation.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_shadow.o = $(CC_FLAGS_FTRACE) CFLAGS_core.o := $(CC_FLAGS_KMSAN_RUNTIME) CFLAGS_hooks.o := $(CC_FLAGS_KMSAN_RUNTIME) From 3cff5b0274e31c62b07c9015b874dd3b4f64b92e Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 15 Feb 2023 14:00:58 +0100 Subject: [PATCH 70/80] objtool: add UACCESS exceptions for __tsan_volatile_read/write A lot of the tsan helpers are already excempt from the UACCESS warnings, but some more functions were added that need the same thing: kernel/kcsan/core.o: warning: objtool: __tsan_volatile_read16+0x0: call to __tsan_unaligned_read16() with UACCESS enabled kernel/kcsan/core.o: warning: objtool: __tsan_volatile_write16+0x0: call to __tsan_unaligned_write16() with UACCESS enabled vmlinux.o: warning: objtool: __tsan_unaligned_volatile_read16+0x4: call to __tsan_unaligned_read16() with UACCESS enabled vmlinux.o: warning: objtool: __tsan_unaligned_volatile_write16+0x4: call to __tsan_unaligned_write16() with UACCESS enabled As Marco points out, these functions don't even call each other explicitly but instead gcc (but not clang) notices the functions being identical and turns one symbol into a direct branch to the other. Link: https://lkml.kernel.org/r/20230215130058.3836177-4-arnd@kernel.org Fixes: 75d75b7a4d54 ("kcsan: Support distinguishing volatile accesses") Signed-off-by: Arnd Bergmann Acked-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Josh Poimboeuf Cc: Kuan-Ying Lee Cc: Peter Zijlstra (Intel) Cc: Vincenzo Frascino Signed-off-by: Andrew Morton --- tools/objtool/check.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 4b7c8b33069e5..b1a5f658673f0 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1186,6 +1186,8 @@ static const char *uaccess_safe_builtin[] = { "__tsan_atomic64_compare_exchange_val", "__tsan_atomic_thread_fence", "__tsan_atomic_signal_fence", + "__tsan_unaligned_read16", + "__tsan_unaligned_write16", /* KCOV */ "write_comp_data", "check_kcov_mode", From a434151df8af8c6828b28871efb42175a0d2839e Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:34 +0800 Subject: [PATCH 71/80] mm: change to return bool for folio_isolate_lru() Patch series "Change the return value for page isolation functions", v3. Now the page isolation functions did not return a boolean to indicate success or not, instead it will return a negative error when failed to isolate a page. So below code used in most places seem a boolean success/failure thing, which can confuse people whether the isolation is successful. if (folio_isolate_lru(folio)) continue; Moreover the page isolation functions only return 0 or -EBUSY, and most users did not care about the negative error except for few users, thus we can convert all page isolation functions to return a boolean value, which can remove the confusion to make code more clear. No functional changes intended in this patch series. This patch (of 4): Now the folio_isolate_lru() did not return a boolean value to indicate isolation success or not, however below code checking the return value can make people think that it was a boolean success/failure thing, which makes people easy to make mistakes (see the fix patch[1]). if (folio_isolate_lru(folio)) continue; Thus it's better to check the negative error value expilictly returned by folio_isolate_lru(), which makes code more clear per Linus's suggestion[2]. Moreover Matthew suggested we can convert the isolation functions to return a boolean[3], since most users did not care about the negative error value, and can also remove the confusing of checking return value. So this patch converts the folio_isolate_lru() to return a boolean value, which means return 'true' to indicate the folio isolation is successful, and 'false' means a failure to isolation. Meanwhile changing all users' logic of checking the isolation state. No functional changes intended. [1] https://lore.kernel.org/all/20230131063206.28820-1-Kuan-Ying.Lee@mediatek.com/T/#u [2] https://lore.kernel.org/all/CAHk-=wiBrY+O-4=2mrbVyxR+hOqfdJ=Do6xoucfJ9_5az01L4Q@mail.gmail.com/ [3] https://lore.kernel.org/all/Y+sTFqwMNAjDvxw3@casper.infradead.org/ Link: https://lkml.kernel.org/r/cover.1676424378.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/8a4e3679ed4196168efadf7ea36c038f2f7d5aa9.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Reviewed-by: SeongJae Park Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Cc: Johannes Weiner Cc: Miaohe Lin Cc: Michal Hocko Cc: Mike Kravetz Cc: Muchun Song Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Roman Gushchin Cc: Shakeel Butt Signed-off-by: Andrew Morton --- mm/damon/paddr.c | 2 +- mm/folio-compat.c | 8 +++++++- mm/gup.c | 2 +- mm/internal.h | 2 +- mm/khugepaged.c | 2 +- mm/madvise.c | 4 ++-- mm/mempolicy.c | 2 +- mm/vmscan.c | 10 +++++----- 8 files changed, 19 insertions(+), 13 deletions(-) diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index b4df9b9bcc0a1..607bb69e526cf 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -246,7 +246,7 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) folio_clear_referenced(folio); folio_test_clear_young(folio); - if (folio_isolate_lru(folio)) { + if (!folio_isolate_lru(folio)) { folio_put(folio); continue; } diff --git a/mm/folio-compat.c b/mm/folio-compat.c index 18c48b5579263..540373cf904e9 100644 --- a/mm/folio-compat.c +++ b/mm/folio-compat.c @@ -115,9 +115,15 @@ EXPORT_SYMBOL(grab_cache_page_write_begin); int isolate_lru_page(struct page *page) { + bool ret; + if (WARN_RATELIMIT(PageTail(page), "trying to isolate tail page")) return -EBUSY; - return folio_isolate_lru((struct folio *)page); + ret = folio_isolate_lru((struct folio *)page); + if (ret) + return 0; + + return -EBUSY; } void putback_lru_page(struct page *page) diff --git a/mm/gup.c b/mm/gup.c index b0885f70579c5..eab18ba045dbe 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1939,7 +1939,7 @@ static unsigned long collect_longterm_unpinnable_pages( drain_allow = false; } - if (folio_isolate_lru(folio)) + if (!folio_isolate_lru(folio)) continue; list_add_tail(&folio->lru, movable_page_list); diff --git a/mm/internal.h b/mm/internal.h index dfb37e94e140c..8645e8496537f 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -188,7 +188,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr, * in mm/vmscan.c: */ int isolate_lru_page(struct page *page); -int folio_isolate_lru(struct folio *folio); +bool folio_isolate_lru(struct folio *folio); void putback_lru_page(struct page *page); void folio_putback_lru(struct folio *folio); extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason); diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a5d32231bfad9..cee659cfa3c1a 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2047,7 +2047,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, goto out_unlock; } - if (folio_isolate_lru(folio)) { + if (!folio_isolate_lru(folio)) { result = SCAN_DEL_PAGE_LRU; goto out_unlock; } diff --git a/mm/madvise.c b/mm/madvise.c index 5a5a687d03c24..c2202f51e9ddf 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -406,7 +406,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, folio_clear_referenced(folio); folio_test_clear_young(folio); if (pageout) { - if (!folio_isolate_lru(folio)) { + if (folio_isolate_lru(folio)) { if (folio_test_unevictable(folio)) folio_putback_lru(folio); else @@ -500,7 +500,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, folio_clear_referenced(folio); folio_test_clear_young(folio); if (pageout) { - if (!folio_isolate_lru(folio)) { + if (folio_isolate_lru(folio)) { if (folio_test_unevictable(folio)) folio_putback_lru(folio); else diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 0919c7a719d41..2751bc3310fd6 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1033,7 +1033,7 @@ static int migrate_folio_add(struct folio *folio, struct list_head *foliolist, * expensive, so check the estimated mapcount of the folio instead. */ if ((flags & MPOL_MF_MOVE_ALL) || folio_estimated_sharers(folio) == 1) { - if (!folio_isolate_lru(folio)) { + if (folio_isolate_lru(folio)) { list_add_tail(&folio->lru, foliolist); node_stat_mod_folio(folio, NR_ISOLATED_ANON + folio_is_file_lru(folio), diff --git a/mm/vmscan.c b/mm/vmscan.c index 098c79129c426..9c1c5e8b24b8f 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2337,12 +2337,12 @@ static unsigned long isolate_lru_folios(unsigned long nr_to_scan, * (2) The lru_lock must not be held. * (3) Interrupts must be enabled. * - * Return: 0 if the folio was removed from an LRU list. - * -EBUSY if the folio was not on an LRU list. + * Return: true if the folio was removed from an LRU list. + * false if the folio was not on an LRU list. */ -int folio_isolate_lru(struct folio *folio) +bool folio_isolate_lru(struct folio *folio) { - int ret = -EBUSY; + bool ret = false; VM_BUG_ON_FOLIO(!folio_ref_count(folio), folio); @@ -2353,7 +2353,7 @@ int folio_isolate_lru(struct folio *folio) lruvec = folio_lruvec_lock_irq(folio); lruvec_del_folio(lruvec, folio); unlock_page_lruvec_irq(lruvec); - ret = 0; + ret = true; } return ret; From cb811bdc78ef6fc5be38b64d8565464d03563687 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:35 +0800 Subject: [PATCH 72/80] mm: change to return bool for isolate_lru_page() The isolate_lru_page() can only return 0 or -EBUSY, and most users did not care about the negative error of isolate_lru_page(), except one user in add_page_for_migration(). So we can convert the isolate_lru_page() to return a boolean value, which can help to make the code more clear when checking the return value of isolate_lru_page(). Also convert all users' logic of checking the isolation state. No functional changes intended. Link: https://lkml.kernel.org/r/3074c1ab628d9dbf139b33f248a8bc253a3f95f0.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/folio-compat.c | 12 +++--------- mm/internal.h | 2 +- mm/khugepaged.c | 2 +- mm/memcontrol.c | 4 ++-- mm/memory-failure.c | 4 ++-- mm/memory_hotplug.c | 8 +++++--- mm/migrate.c | 9 ++++++--- mm/migrate_device.c | 2 +- 8 files changed, 21 insertions(+), 22 deletions(-) diff --git a/mm/folio-compat.c b/mm/folio-compat.c index 540373cf904e9..cabcd1de9ecbb 100644 --- a/mm/folio-compat.c +++ b/mm/folio-compat.c @@ -113,17 +113,11 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping, } EXPORT_SYMBOL(grab_cache_page_write_begin); -int isolate_lru_page(struct page *page) +bool isolate_lru_page(struct page *page) { - bool ret; - if (WARN_RATELIMIT(PageTail(page), "trying to isolate tail page")) - return -EBUSY; - ret = folio_isolate_lru((struct folio *)page); - if (ret) - return 0; - - return -EBUSY; + return false; + return folio_isolate_lru((struct folio *)page); } void putback_lru_page(struct page *page) diff --git a/mm/internal.h b/mm/internal.h index 8645e8496537f..fc01fd092ea58 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -187,7 +187,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr, /* * in mm/vmscan.c: */ -int isolate_lru_page(struct page *page); +bool isolate_lru_page(struct page *page); bool folio_isolate_lru(struct folio *folio); void putback_lru_page(struct page *page); void folio_putback_lru(struct folio *folio); diff --git a/mm/khugepaged.c b/mm/khugepaged.c index cee659cfa3c1a..8dbc398968110 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -659,7 +659,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma, * Isolate the page to avoid collapsing an hugepage * currently in use by the VM. */ - if (isolate_lru_page(page)) { + if (!isolate_lru_page(page)) { unlock_page(page); result = SCAN_DEL_PAGE_LRU; goto out; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 3e3cdb9bed952..25f2465d5a37b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6176,7 +6176,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); if (target_type == MC_TARGET_PAGE) { page = target.page; - if (!isolate_lru_page(page)) { + if (isolate_lru_page(page)) { if (!mem_cgroup_move_account(page, true, mc.from, mc.to)) { mc.precharge -= HPAGE_PMD_NR; @@ -6226,7 +6226,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, */ if (PageTransCompound(page)) goto put; - if (!device && isolate_lru_page(page)) + if (!device && !isolate_lru_page(page)) goto put; if (!mem_cgroup_move_account(page, false, mc.from, mc.to)) { diff --git a/mm/memory-failure.c b/mm/memory-failure.c index db85c2d37f70a..e504362fdb235 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -846,7 +846,7 @@ static const char * const action_page_types[] = { */ static int delete_from_lru_cache(struct page *p) { - if (!isolate_lru_page(p)) { + if (isolate_lru_page(p)) { /* * Clear sensible page flags, so that the buddy system won't * complain when the page is unpoison-and-freed. @@ -2513,7 +2513,7 @@ static bool isolate_page(struct page *page, struct list_head *pagelist) bool lru = !__PageMovable(page); if (lru) - isolated = !isolate_lru_page(page); + isolated = isolate_lru_page(page); else isolated = !isolate_movable_page(page, ISOLATE_UNEVICTABLE); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a1e8c3e9ab080..5fc2dcf4e3abe 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1632,6 +1632,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) for (pfn = start_pfn; pfn < end_pfn; pfn++) { struct folio *folio; + bool isolated; if (!pfn_valid(pfn)) continue; @@ -1667,9 +1668,10 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) * We can skip free pages. And we can deal with pages on * LRU and non-lru movable pages. */ - if (PageLRU(page)) - ret = isolate_lru_page(page); - else + if (PageLRU(page)) { + isolated = isolate_lru_page(page); + ret = isolated ? 0 : -EBUSY; + } else ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); if (!ret) { /* Success */ list_add_tail(&page->lru, &source); diff --git a/mm/migrate.c b/mm/migrate.c index 40c63e77e91fb..e8e87da850ea3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2134,11 +2134,14 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, } } else { struct page *head; + bool isolated; head = compound_head(page); - err = isolate_lru_page(head); - if (err) + isolated = isolate_lru_page(head); + if (!isolated) { + err = -EBUSY; goto out_putpage; + } err = 1; list_add_tail(&head->lru, pagelist); @@ -2543,7 +2546,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) return 0; } - if (isolate_lru_page(page)) + if (!isolate_lru_page(page)) return 0; mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_is_file_lru(page), diff --git a/mm/migrate_device.c b/mm/migrate_device.c index 6c3740318a98c..d30c9de60b0d7 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -388,7 +388,7 @@ static unsigned long migrate_device_unmap(unsigned long *src_pfns, allow_drain = false; } - if (isolate_lru_page(page)) { + if (!isolate_lru_page(page)) { src_pfns[i] &= ~MIGRATE_PFN_MIGRATE; restore++; continue; From 76d75df08412ebe2d25e8c22e3eb5013952ef642 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:36 +0800 Subject: [PATCH 73/80] mm: hugetlb: change to return bool for isolate_hugetlb() Now the isolate_hugetlb() only returns 0 or -EBUSY, and most users did not care about the negative value, thus we can convert the isolate_hugetlb() to return a boolean value to make code more clear when checking the hugetlb isolation state. Moreover converts 2 users which will consider the negative value returned by isolate_hugetlb(). No functional changes intended. Link: https://lkml.kernel.org/r/12a287c5bebc13df304387087bbecc6421510849.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Mike Kravetz Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 6 +++--- mm/hugetlb.c | 13 ++++++++----- mm/memory-failure.c | 2 +- mm/mempolicy.c | 2 +- mm/migrate.c | 7 +++---- 5 files changed, 16 insertions(+), 14 deletions(-) diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 8b45720f94756..7c977d234aba3 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -171,7 +171,7 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to, vm_flags_t vm_flags); long hugetlb_unreserve_pages(struct inode *inode, long start, long end, long freed); -int isolate_hugetlb(struct folio *folio, struct list_head *list); +bool isolate_hugetlb(struct folio *folio, struct list_head *list); int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison); int get_huge_page_for_hwpoison(unsigned long pfn, int flags, bool *migratable_cleared); @@ -413,9 +413,9 @@ static inline pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, return NULL; } -static inline int isolate_hugetlb(struct folio *folio, struct list_head *list) +static inline bool isolate_hugetlb(struct folio *folio, struct list_head *list) { - return -EBUSY; + return false; } static inline int get_hwpoison_hugetlb_folio(struct folio *folio, bool *hugetlb, bool unpoison) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 3a01a9dbf445a..16513cd23d5d7 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2925,13 +2925,16 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h, */ goto free_new; } else if (folio_ref_count(old_folio)) { + bool isolated; + /* * Someone has grabbed the folio, try to isolate it here. * Fail with -EBUSY if not possible. */ spin_unlock_irq(&hugetlb_lock); - ret = isolate_hugetlb(old_folio, list); + isolated = isolate_hugetlb(old_folio, list); spin_lock_irq(&hugetlb_lock); + ret = isolated ? 0 : -EBUSY; goto free_new; } else if (!folio_test_hugetlb_freed(old_folio)) { /* @@ -3005,7 +3008,7 @@ int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list) if (hstate_is_gigantic(h)) return -ENOMEM; - if (folio_ref_count(folio) && !isolate_hugetlb(folio, list)) + if (folio_ref_count(folio) && isolate_hugetlb(folio, list)) ret = 0; else if (!folio_ref_count(folio)) ret = alloc_and_dissolve_hugetlb_folio(h, folio, list); @@ -7251,15 +7254,15 @@ __weak unsigned long hugetlb_mask_last_page(struct hstate *h) * These functions are overwritable if your architecture needs its own * behavior. */ -int isolate_hugetlb(struct folio *folio, struct list_head *list) +bool isolate_hugetlb(struct folio *folio, struct list_head *list) { - int ret = 0; + bool ret = true; spin_lock_irq(&hugetlb_lock); if (!folio_test_hugetlb(folio) || !folio_test_hugetlb_migratable(folio) || !folio_try_get(folio)) { - ret = -EBUSY; + ret = false; goto unlock; } folio_clear_hugetlb_migratable(folio); diff --git a/mm/memory-failure.c b/mm/memory-failure.c index e504362fdb235..8604753bc6444 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2508,7 +2508,7 @@ static bool isolate_page(struct page *page, struct list_head *pagelist) bool isolated = false; if (PageHuge(page)) { - isolated = !isolate_hugetlb(page_folio(page), pagelist); + isolated = isolate_hugetlb(page_folio(page), pagelist); } else { bool lru = !__PageMovable(page); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 2751bc3310fd6..a256a241fd1da 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -609,7 +609,7 @@ static int queue_folios_hugetlb(pte_t *pte, unsigned long hmask, if (flags & (MPOL_MF_MOVE_ALL) || (flags & MPOL_MF_MOVE && folio_estimated_sharers(folio) == 1 && !hugetlb_pmd_shared(pte))) { - if (isolate_hugetlb(folio, qp->pagelist) && + if (!isolate_hugetlb(folio, qp->pagelist) && (flags & MPOL_MF_STRICT)) /* * Failed to isolate folio but allow migrating pages diff --git a/mm/migrate.c b/mm/migrate.c index e8e87da850ea3..3516ba8d5e98d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2097,6 +2097,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, struct vm_area_struct *vma; struct page *page; int err; + bool isolated; mmap_read_lock(mm); err = -EFAULT; @@ -2128,13 +2129,11 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, if (PageHuge(page)) { if (PageHead(page)) { - err = isolate_hugetlb(page_folio(page), pagelist); - if (!err) - err = 1; + isolated = isolate_hugetlb(page_folio(page), pagelist); + err = isolated ? 1 : -EBUSY; } } else { struct page *head; - bool isolated; head = compound_head(page); isolated = isolate_lru_page(head); From 296b8b566b73a1dc2c125db9b7d90a4592026185 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Wed, 15 Feb 2023 12:53:56 -0800 Subject: [PATCH 74/80] mm-hugetlb-change-to-return-bool-for-isolate_hugetlb-fix shorten locked section, per SeongJae Park Cc: Baolin Wang Cc: David Hildenbrand Cc: Linus Torvalds Cc: Matthew Wilcox (Oracle) Cc: Mike Kravetz Cc: SeongJae Park Signed-off-by: Andrew Morton --- mm/hugetlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 16513cd23d5d7..07abcb6eb2030 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2933,8 +2933,8 @@ static int alloc_and_dissolve_hugetlb_folio(struct hstate *h, */ spin_unlock_irq(&hugetlb_lock); isolated = isolate_hugetlb(old_folio, list); - spin_lock_irq(&hugetlb_lock); ret = isolated ? 0 : -EBUSY; + spin_lock_irq(&hugetlb_lock); goto free_new; } else if (!folio_test_hugetlb_freed(old_folio)) { /* From 272824b3d8bc1f353bb47172cc38fcc9378df0a9 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:37 +0800 Subject: [PATCH 75/80] mm: change to return bool for isolate_movable_page() Now the isolate_movable_page() can only return 0 or -EBUSY, and no users will care about the negative return value, thus we can convert the isolate_movable_page() to return a boolean value to make the code more clear when checking the movable page isolation state. No functional changes intended. Link: https://lkml.kernel.org/r/cb877f73f4fff8d309611082ec740a7065b1ade0.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- include/linux/migrate.h | 6 +++--- mm/compaction.c | 2 +- mm/memory-failure.c | 4 ++-- mm/memory_hotplug.c | 10 +++++----- mm/migrate.c | 6 +++--- 5 files changed, 14 insertions(+), 14 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index c88b96b48be70..6b252f519c868 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -71,7 +71,7 @@ extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, unsigned long private, enum migrate_mode mode, int reason, unsigned int *ret_succeeded); extern struct page *alloc_migration_target(struct page *page, unsigned long private); -extern int isolate_movable_page(struct page *page, isolate_mode_t mode); +extern bool isolate_movable_page(struct page *page, isolate_mode_t mode); int migrate_huge_page_move_mapping(struct address_space *mapping, struct folio *dst, struct folio *src); @@ -92,8 +92,8 @@ static inline int migrate_pages(struct list_head *l, new_page_t new, static inline struct page *alloc_migration_target(struct page *page, unsigned long private) { return NULL; } -static inline int isolate_movable_page(struct page *page, isolate_mode_t mode) - { return -EBUSY; } +static inline bool isolate_movable_page(struct page *page, isolate_mode_t mode) + { return false; } static inline int migrate_huge_page_move_mapping(struct address_space *mapping, struct folio *dst, struct folio *src) diff --git a/mm/compaction.c b/mm/compaction.c index d73578af44cc1..ad7409f705190 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -976,7 +976,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, locked = NULL; } - if (!isolate_movable_page(page, mode)) + if (isolate_movable_page(page, mode)) goto isolate_success; } diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 8604753bc6444..a1ede7bdce95e 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2515,8 +2515,8 @@ static bool isolate_page(struct page *page, struct list_head *pagelist) if (lru) isolated = isolate_lru_page(page); else - isolated = !isolate_movable_page(page, - ISOLATE_UNEVICTABLE); + isolated = isolate_movable_page(page, + ISOLATE_UNEVICTABLE); if (isolated) { list_add(&page->lru, pagelist); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 5fc2dcf4e3abe..bcb0dc41c2f28 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1668,18 +1668,18 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) * We can skip free pages. And we can deal with pages on * LRU and non-lru movable pages. */ - if (PageLRU(page)) { + if (PageLRU(page)) isolated = isolate_lru_page(page); - ret = isolated ? 0 : -EBUSY; - } else - ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); - if (!ret) { /* Success */ + else + isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE); + if (isolated) { /* Success */ list_add_tail(&page->lru, &source); if (!__PageMovable(page)) inc_node_page_state(page, NR_ISOLATED_ANON + page_is_file_lru(page)); } else { + ret = -EBUSY; if (__ratelimit(&migrate_rs)) { pr_warn("failed to isolate pfn %lx\n", pfn); dump_page(page, "isolation failed"); diff --git a/mm/migrate.c b/mm/migrate.c index 3516ba8d5e98d..37865f85df6d4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -58,7 +58,7 @@ #include "internal.h" -int isolate_movable_page(struct page *page, isolate_mode_t mode) +bool isolate_movable_page(struct page *page, isolate_mode_t mode) { struct folio *folio = folio_get_nontail_page(page); const struct movable_operations *mops; @@ -119,14 +119,14 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) folio_set_isolated(folio); folio_unlock(folio); - return 0; + return true; out_no_isolated: folio_unlock(folio); out_putfolio: folio_put(folio); out: - return -EBUSY; + return false; } static void putback_movable_folio(struct folio *folio) From 6905915500816fed9b27d722e1a392ff66016184 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Thu, 16 Feb 2023 14:41:42 -0800 Subject: [PATCH 76/80] mm-change-to-return-bool-for-isolate_movable_page-fix remove unneeded comment, per Matthew Cc: Baolin Wang Cc: David Hildenbrand Cc: Linus Torvalds Cc: Matthew Wilcox (Oracle) Cc: SeongJae Park Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index bcb0dc41c2f28..5f73fd894b897 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1672,7 +1672,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) isolated = isolate_lru_page(page); else isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE); - if (isolated) { /* Success */ + if (isolated) { list_add_tail(&page->lru, &source); if (!__PageMovable(page)) inc_node_page_state(page, NR_ISOLATED_ANON + From dac4d0e17b7540b0d6f81b8dc77b0d154b3a97c5 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 15 Feb 2023 15:58:00 -0500 Subject: [PATCH 77/80] mm/uffd: fix comment in handling pte markers The comment is obsolete after f369b07c8614 ("mm/uffd: reset write protection when unregister with wp-mode", 2022-08-20). Remove it. Link: https://lkml.kernel.org/r/20230215205800.223549-1-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: David Hildenbrand Cc: Andrea Arcangeli Cc: Axel Rasmussen Signed-off-by: Andrew Morton --- mm/memory.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 7a04a1130ec15..f456f3b5049cf 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3627,9 +3627,7 @@ static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf) { /* * Just in case there're leftover special ptes even after the region - * got unregistered - we can simply clear them. We can also do that - * proactively when e.g. when we do UFFDIO_UNREGISTER upon some uffd-wp - * ranges, but it should be more efficient to be done lazily here. + * got unregistered - we can simply clear them. */ if (unlikely(!userfaultfd_wp(vmf->vma) || vma_is_anonymous(vmf->vma))) return pte_marker_clear(vmf); From b13b038fdf0e18f9a8e3c63f06820e8195441602 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Thu, 16 Feb 2023 17:07:03 +0000 Subject: [PATCH 78/80] mm/memory_hotplug: cleanup return value handing in do_migrate_range() Return value mechanism of do_migrate_range() is not very simple, while no caller of the function checks the return value. Make the function return nothing to be more simple, and cleanup related unnecessary code. Link: https://lkml.kernel.org/r/20230216170703.64574-1-sj@kernel.org Suggested-by: David Hildenbrand Acked-by: David Hildenbrand Reviewed-by: Baolin Wang Signed-off-by: SeongJae Park Cc: Oscar Salvador Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 5f73fd894b897..db3b270254f1e 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1620,12 +1620,10 @@ static int scan_movable_pages(unsigned long start, unsigned long end, return 0; } -static int -do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) +static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; struct page *page, *head; - int ret = 0; LIST_HEAD(source); static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); @@ -1679,7 +1677,6 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) page_is_file_lru(page)); } else { - ret = -EBUSY; if (__ratelimit(&migrate_rs)) { pr_warn("failed to isolate pfn %lx\n", pfn); dump_page(page, "isolation failed"); @@ -1693,6 +1690,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) .nmask = &nmask, .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, }; + int ret; /* * We have checked that migration range is on a single zone so @@ -1721,8 +1719,6 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) putback_movable_pages(&source); } } - - return ret; } static int __init cmdline_parse_movable_node(char *p) From 440b18fc3074a5146b6eb12d5f4fe0933fe89f75 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Thu, 16 Feb 2023 14:44:24 -0800 Subject: [PATCH 79/80] include/linux/migrate.h: remove unneeded externs As suggested by Matthew. Suggested-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- include/linux/migrate.h | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 6b252f519c868..6241a1596a755 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -62,16 +62,16 @@ extern const char *migrate_reason_names[MR_TYPES]; #ifdef CONFIG_MIGRATION -extern void putback_movable_pages(struct list_head *l); +void putback_movable_pages(struct list_head *l); int migrate_folio_extra(struct address_space *mapping, struct folio *dst, struct folio *src, enum migrate_mode mode, int extra_count); int migrate_folio(struct address_space *mapping, struct folio *dst, struct folio *src, enum migrate_mode mode); -extern int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, - unsigned long private, enum migrate_mode mode, int reason, - unsigned int *ret_succeeded); -extern struct page *alloc_migration_target(struct page *page, unsigned long private); -extern bool isolate_movable_page(struct page *page, isolate_mode_t mode); +int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, + unsigned long private, enum migrate_mode mode, int reason, + unsigned int *ret_succeeded); +struct page *alloc_migration_target(struct page *page, unsigned long private); +bool isolate_movable_page(struct page *page, isolate_mode_t mode); int migrate_huge_page_move_mapping(struct address_space *mapping, struct folio *dst, struct folio *src); @@ -142,8 +142,8 @@ const struct movable_operations *page_movable_ops(struct page *page) } #ifdef CONFIG_NUMA_BALANCING -extern int migrate_misplaced_page(struct page *page, - struct vm_area_struct *vma, int node); +int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, + int node); #else static inline int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma, int node) From 7698bb96507a6bd8f5f56a79a46d9a8a506931bd Mon Sep 17 00:00:00 2001 From: Wang Yong Date: Mon, 13 Feb 2023 14:08:08 +0800 Subject: [PATCH 80/80] delayacct: improve the average delay precision of getdelay tool to microsecond Improve the average delay precision of getdelay tool to microsecond. When using the getdelay tool, it is sometimes found that the average delay except CPU is not 0, but display is 0, because the precison is too low. For example, see delay average of SWAP below when using ZRAM. print delayacct stats ON PID 32915 CPU count real total virtual total delay total delay average 339202 2793871936 9233585504 7951112 0.000ms IO count delay total delay average 41 419296904 10ms SWAP count delay total delay average 242589 1045792384 0ms This wrong display is misleading, so improve the millisecond precision of the average delay to microsecond just like CPU. Then user would get more accurate information of delay time. Link: https://lkml.kernel.org/r/202302131408087983857@zte.com.cn Signed-off-by: Wang Yong Reviewed-by: Yang Yang Cc: David Hildenbrand Signed-off-by: Andrew Morton --- Documentation/accounting/delay-accounting.rst | 14 +++++------ .../zh_CN/accounting/delay-accounting.rst | 10 ++++---- tools/accounting/getdelays.c | 24 +++++++++---------- 3 files changed, 24 insertions(+), 24 deletions(-) diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index 7103b62ba6d7e..79f537c9f160b 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -109,17 +109,17 @@ Get sum of delays, since system boot, for all pids with tgid 5:: CPU count real total virtual total delay total delay average 8 7000000 6872122 3382277 0.423ms IO count delay total delay average - 0 0 0ms + 0 0 0.000ms SWAP count delay total delay average - 0 0 0ms + 0 0 0.000ms RECLAIM count delay total delay average - 0 0 0ms + 0 0 0.000ms THRASHING count delay total delay average - 0 0 0ms + 0 0 0.000ms COMPACT count delay total delay average - 0 0 0ms - WPCOPY count delay total delay average - 0 0 0ms + 0 0 0.000ms + WPCOPY count delay total delay average + 0 0 0.000ms Get IO accounting for pid 1, it works only with -p:: diff --git a/Documentation/translations/zh_CN/accounting/delay-accounting.rst b/Documentation/translations/zh_CN/accounting/delay-accounting.rst index f1849411018e9..5623f555d7c55 100644 --- a/Documentation/translations/zh_CN/accounting/delay-accounting.rst +++ b/Documentation/translations/zh_CN/accounting/delay-accounting.rst @@ -91,15 +91,15 @@ getdelays命令的一般格式:: CPU count real total virtual total delay total delay average 8 7000000 6872122 3382277 0.423ms IO count delay total delay average - 0 0 0ms + 0 0 0.000ms SWAP count delay total delay average - 0 0 0ms + 0 0 0.000ms RECLAIM count delay total delay average - 0 0 0ms + 0 0 0.000ms THRASHING count delay total delay average - 0 0 0ms + 0 0 0.000ms COMPACT count delay total delay average - 0 0 0ms + 0 0 0.000ms 获取pid为1的IO计数，它只和-p一起使用:: # ./getdelays -i -p 1 diff --git a/tools/accounting/getdelays.c b/tools/accounting/getdelays.c index 938dec0dfaad8..23a15d8f2bf4f 100644 --- a/tools/accounting/getdelays.c +++ b/tools/accounting/getdelays.c @@ -198,17 +198,17 @@ static void print_delayacct(struct taskstats *t) printf("\n\nCPU %15s%15s%15s%15s%15s\n" " %15llu%15llu%15llu%15llu%15.3fms\n" "IO %15s%15s%15s\n" - " %15llu%15llu%15llums\n" + " %15llu%15llu%15.3fms\n" "SWAP %15s%15s%15s\n" - " %15llu%15llu%15llums\n" + " %15llu%15llu%15.3fms\n" "RECLAIM %12s%15s%15s\n" - " %15llu%15llu%15llums\n" + " %15llu%15llu%15.3fms\n" "THRASHING%12s%15s%15s\n" - " %15llu%15llu%15llums\n" + " %15llu%15llu%15.3fms\n" "COMPACT %12s%15s%15s\n" - " %15llu%15llu%15llums\n" + " %15llu%15llu%15.3fms\n" "WPCOPY %12s%15s%15s\n" - " %15llu%15llu%15llums\n", + " %15llu%15llu%15.3fms\n", "count", "real total", "virtual total", "delay total", "delay average", (unsigned long long)t->cpu_count, @@ -219,27 +219,27 @@ static void print_delayacct(struct taskstats *t) "count", "delay total", "delay average", (unsigned long long)t->blkio_count, (unsigned long long)t->blkio_delay_total, - average_ms(t->blkio_delay_total, t->blkio_count), + average_ms((double)t->blkio_delay_total, t->blkio_count), "count", "delay total", "delay average", (unsigned long long)t->swapin_count, (unsigned long long)t->swapin_delay_total, - average_ms(t->swapin_delay_total, t->swapin_count), + average_ms((double)t->swapin_delay_total, t->swapin_count), "count", "delay total", "delay average", (unsigned long long)t->freepages_count, (unsigned long long)t->freepages_delay_total, - average_ms(t->freepages_delay_total, t->freepages_count), + average_ms((double)t->freepages_delay_total, t->freepages_count), "count", "delay total", "delay average", (unsigned long long)t->thrashing_count, (unsigned long long)t->thrashing_delay_total, - average_ms(t->thrashing_delay_total, t->thrashing_count), + average_ms((double)t->thrashing_delay_total, t->thrashing_count), "count", "delay total", "delay average", (unsigned long long)t->compact_count, (unsigned long long)t->compact_delay_total, - average_ms(t->compact_delay_total, t->compact_count), + average_ms((double)t->compact_delay_total, t->compact_count), "count", "delay total", "delay average", (unsigned long long)t->wpcopy_count, (unsigned long long)t->wpcopy_delay_total, - average_ms(t->wpcopy_delay_total, t->wpcopy_count)); + average_ms((double)t->wpcopy_delay_total, t->wpcopy_count)); } static void task_context_switch_counts(struct taskstats *t)