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ext4: Add configurable run-time mballoc debugging
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Allow mballoc debugging to be enabled at run-time instead of just at
compile time.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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Theodore Ts'o committed Sep 18, 2009
1 parent 91cc219 commit 6ba495e
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Showing 3 changed files with 80 additions and 26 deletions.
9 changes: 9 additions & 0 deletions fs/ext4/Kconfig
View file
Original file line number Diff line number Diff line change
Expand Up @@ -77,3 +77,12 @@ config EXT4_FS_SECURITY

If you are not using a security module that requires using
extended attributes for file security labels, say N.

config EXT4_DEBUG
bool "EXT4 debugging support"
depends on EXT4_FS
help
Enables run-time debugging support for the ext4 filesystem.

If you select Y here, then you will be able to turn on debugging
with a command such as "echo 1 > /sys/kernel/debug/ext4/mballoc-debug"
81 changes: 59 additions & 22 deletions fs/ext4/mballoc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
*/

#include "mballoc.h"
#include <linux/debugfs.h>
#include <trace/events/ext4.h>

/*
Expand Down Expand Up @@ -743,7 +744,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
char *data;
char *bitmap;

mb_debug("init page %lu\n", page->index);
mb_debug(1, "init page %lu\n", page->index);

inode = page->mapping->host;
sb = inode->i_sb;
Expand Down Expand Up @@ -822,7 +823,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
set_bitmap_uptodate(bh[i]);
bh[i]->b_end_io = end_buffer_read_sync;
submit_bh(READ, bh[i]);
mb_debug("read bitmap for group %u\n", first_group + i);
mb_debug(1, "read bitmap for group %u\n", first_group + i);
}

/* wait for I/O completion */
Expand Down Expand Up @@ -862,7 +863,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
if ((first_block + i) & 1) {
/* this is block of buddy */
BUG_ON(incore == NULL);
mb_debug("put buddy for group %u in page %lu/%x\n",
mb_debug(1, "put buddy for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
grinfo = ext4_get_group_info(sb, group);
grinfo->bb_fragments = 0;
Expand All @@ -878,7 +879,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
} else {
/* this is block of bitmap */
BUG_ON(incore != NULL);
mb_debug("put bitmap for group %u in page %lu/%x\n",
mb_debug(1, "put bitmap for group %u in page %lu/%x\n",
group, page->index, i * blocksize);

/* see comments in ext4_mb_put_pa() */
Expand Down Expand Up @@ -922,7 +923,7 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;

mb_debug("load group %u\n", group);
mb_debug(1, "load group %u\n", group);

blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
grp = ext4_get_group_info(sb, group);
Expand Down Expand Up @@ -1851,7 +1852,7 @@ int ext4_mb_init_group(struct super_block *sb, ext4_group_t group)
struct inode *inode = sbi->s_buddy_cache;
struct page *page = NULL, *bitmap_page = NULL;

mb_debug("init group %u\n", group);
mb_debug(1, "init group %u\n", group);
blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
this_grp = ext4_get_group_info(sb, group);
/*
Expand Down Expand Up @@ -2739,7 +2740,7 @@ static void ext4_mb_cleanup_pa(struct ext4_group_info *grp)
kmem_cache_free(ext4_pspace_cachep, pa);
}
if (count)
mb_debug("mballoc: %u PAs left\n", count);
mb_debug(1, "mballoc: %u PAs left\n", count);

}

Expand Down Expand Up @@ -2820,7 +2821,7 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
list_for_each_safe(l, ltmp, &txn->t_private_list) {
entry = list_entry(l, struct ext4_free_data, list);

mb_debug("gonna free %u blocks in group %u (0x%p):",
mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
entry->count, entry->group, entry);

err = ext4_mb_load_buddy(sb, entry->group, &e4b);
Expand Down Expand Up @@ -2855,9 +2856,43 @@ static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
ext4_mb_release_desc(&e4b);
}

mb_debug("freed %u blocks in %u structures\n", count, count2);
mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
}

#ifdef CONFIG_EXT4_DEBUG
u8 mb_enable_debug __read_mostly;

static struct dentry *debugfs_dir;
static struct dentry *debugfs_debug;

static void __init ext4_create_debugfs_entry(void)
{
debugfs_dir = debugfs_create_dir("ext4", NULL);
if (debugfs_dir)
debugfs_debug = debugfs_create_u8("mballoc-debug",
S_IRUGO | S_IWUSR,
debugfs_dir,
&mb_enable_debug);
}

static void ext4_remove_debugfs_entry(void)
{
debugfs_remove(debugfs_debug);
debugfs_remove(debugfs_dir);
}

#else

static void __init ext4_create_debugfs_entry(void)
{
}

static void ext4_remove_debugfs_entry(void)
{
}

#endif

int __init init_ext4_mballoc(void)
{
ext4_pspace_cachep =
Expand Down Expand Up @@ -2885,6 +2920,7 @@ int __init init_ext4_mballoc(void)
kmem_cache_destroy(ext4_ac_cachep);
return -ENOMEM;
}
ext4_create_debugfs_entry();
return 0;
}

Expand All @@ -2898,6 +2934,7 @@ void exit_ext4_mballoc(void)
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
kmem_cache_destroy(ext4_free_ext_cachep);
ext4_remove_debugfs_entry();
}


Expand Down Expand Up @@ -3042,7 +3079,7 @@ static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_stripe;
else
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
mb_debug("#%u: goal %u blocks for locality group\n",
mb_debug(1, "#%u: goal %u blocks for locality group\n",
current->pid, ac->ac_g_ex.fe_len);
}

Expand Down Expand Up @@ -3232,7 +3269,7 @@ ext4_mb_normalize_request(struct ext4_allocation_context *ac,
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}

mb_debug("goal: %u(was %u) blocks at %u\n", (unsigned) size,
mb_debug(1, "goal: %u(was %u) blocks at %u\n", (unsigned) size,
(unsigned) orig_size, (unsigned) start);
}

Expand Down Expand Up @@ -3281,7 +3318,7 @@ static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
BUG_ON(pa->pa_free < len);
pa->pa_free -= len;

mb_debug("use %llu/%u from inode pa %p\n", start, len, pa);
mb_debug(1, "use %llu/%u from inode pa %p\n", start, len, pa);
}

/*
Expand All @@ -3305,7 +3342,7 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
* in on-disk bitmap -- see ext4_mb_release_context()
* Other CPUs are prevented from allocating from this pa by lg_mutex
*/
mb_debug("use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
mb_debug(1, "use %u/%u from group pa %p\n", pa->pa_lstart-len, len, pa);
}

/*
Expand Down Expand Up @@ -3484,7 +3521,7 @@ void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
preallocated += len;
count++;
}
mb_debug("prellocated %u for group %u\n", preallocated, group);
mb_debug(1, "prellocated %u for group %u\n", preallocated, group);
}

static void ext4_mb_pa_callback(struct rcu_head *head)
Expand Down Expand Up @@ -3619,7 +3656,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
pa->pa_deleted = 0;
pa->pa_type = MB_INODE_PA;

mb_debug("new inode pa %p: %llu/%u for %u\n", pa,
mb_debug(1, "new inode pa %p: %llu/%u for %u\n", pa,
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_inode_pa(ac, pa);

Expand Down Expand Up @@ -3679,7 +3716,7 @@ ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
pa->pa_deleted = 0;
pa->pa_type = MB_GROUP_PA;

mb_debug("new group pa %p: %llu/%u for %u\n", pa,
mb_debug(1, "new group pa %p: %llu/%u for %u\n", pa,
pa->pa_pstart, pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_group_pa(ac, pa);

Expand Down Expand Up @@ -3758,7 +3795,7 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
le32_to_cpu(sbi->s_es->s_first_data_block);
mb_debug(" free preallocated %u/%u in group %u\n",
mb_debug(1, " free preallocated %u/%u in group %u\n",
(unsigned) start, (unsigned) next - bit,
(unsigned) group);
free += next - bit;
Expand Down Expand Up @@ -3849,7 +3886,7 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
int busy = 0;
int free = 0;

mb_debug("discard preallocation for group %u\n", group);
mb_debug(1, "discard preallocation for group %u\n", group);

if (list_empty(&grp->bb_prealloc_list))
return 0;
Expand Down Expand Up @@ -3973,7 +4010,7 @@ void ext4_discard_preallocations(struct inode *inode)
return;
}

mb_debug("discard preallocation for inode %lu\n", inode->i_ino);
mb_debug(1, "discard preallocation for inode %lu\n", inode->i_ino);
trace_ext4_discard_preallocations(inode);

INIT_LIST_HEAD(&list);
Expand Down Expand Up @@ -4078,7 +4115,7 @@ static void ext4_mb_return_to_preallocation(struct inode *inode,
{
BUG_ON(!list_empty(&EXT4_I(inode)->i_prealloc_list));
}
#ifdef MB_DEBUG
#ifdef CONFIG_EXT4_DEBUG
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
Expand Down Expand Up @@ -4227,7 +4264,7 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac,
* locality group. this is a policy, actually */
ext4_mb_group_or_file(ac);

mb_debug("init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
mb_debug(1, "init ac: %u blocks @ %u, goal %u, flags %x, 2^%d, "
"left: %u/%u, right %u/%u to %swritable\n",
(unsigned) ar->len, (unsigned) ar->logical,
(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
Expand All @@ -4249,7 +4286,7 @@ ext4_mb_discard_lg_preallocations(struct super_block *sb,
struct ext4_prealloc_space *pa, *tmp;
struct ext4_allocation_context *ac;

mb_debug("discard locality group preallocation\n");
mb_debug(1, "discard locality group preallocation\n");

INIT_LIST_HEAD(&discard_list);
ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
Expand Down
16 changes: 12 additions & 4 deletions fs/ext4/mballoc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,19 @@

/*
*/
#define MB_DEBUG__
#ifdef MB_DEBUG
#define mb_debug(fmt, a...) printk(fmt, ##a)
#ifdef CONFIG_EXT4_DEBUG
extern u8 mb_enable_debug;

#define mb_debug(n, fmt, a...) \
do { \
if ((n) <= mb_enable_debug) { \
printk(KERN_DEBUG "(%s, %d): %s: ", \
__FILE__, __LINE__, __func__); \
printk(fmt, ## a); \
} \
} while (0)
#else
#define mb_debug(fmt, a...)
#define mb_debug(n, fmt, a...)
#endif

/*
Expand Down

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