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mm: memcontrol: eliminate raw access to stat and event counters
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Replace all raw 'this_cpu_' modifications of the stat and event per-cpu
counters with API functions such as mod_memcg_state().

This makes the code easier to read, but is also in preparation for the
next patch, which changes the per-cpu implementation of those counters.

Link: http://lkml.kernel.org/r/20171103153336.24044-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored and Linus Torvalds committed Feb 1, 2018
1 parent 2b9fceb commit c9019e9
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Showing 2 changed files with 45 additions and 45 deletions.
31 changes: 20 additions & 11 deletions include/linux/memcontrol.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -272,13 +272,6 @@ static inline bool mem_cgroup_disabled(void)
return !cgroup_subsys_enabled(memory_cgrp_subsys);
}

static inline void mem_cgroup_event(struct mem_cgroup *memcg,
enum memcg_event_item event)
{
this_cpu_inc(memcg->stat->events[event]);
cgroup_file_notify(&memcg->events_file);
}

bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);

int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
Expand Down Expand Up @@ -627,15 +620,23 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
gfp_t gfp_mask,
unsigned long *total_scanned);

/* idx can be of type enum memcg_event_item or vm_event_item */
static inline void __count_memcg_events(struct mem_cgroup *memcg,
int idx, unsigned long count)
{
if (!mem_cgroup_disabled())
__this_cpu_add(memcg->stat->events[idx], count);
}

/* idx can be of type enum memcg_event_item or vm_event_item */
static inline void count_memcg_events(struct mem_cgroup *memcg,
enum vm_event_item idx,
unsigned long count)
int idx, unsigned long count)
{
if (!mem_cgroup_disabled())
this_cpu_add(memcg->stat->events[idx], count);
}

/* idx can be of type enum memcg_stat_item or node_stat_item */
/* idx can be of type enum memcg_event_item or vm_event_item */
static inline void count_memcg_page_event(struct page *page,
int idx)
{
Expand All @@ -654,12 +655,20 @@ static inline void count_memcg_event_mm(struct mm_struct *mm,
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (likely(memcg)) {
this_cpu_inc(memcg->stat->events[idx]);
count_memcg_events(memcg, idx, 1);
if (idx == OOM_KILL)
cgroup_file_notify(&memcg->events_file);
}
rcu_read_unlock();
}

static inline void mem_cgroup_event(struct mem_cgroup *memcg,
enum memcg_event_item event)
{
count_memcg_events(memcg, event, 1);
cgroup_file_notify(&memcg->events_file);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head);
#endif
Expand Down
59 changes: 25 additions & 34 deletions mm/memcontrol.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -586,23 +586,23 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
* counted as CACHE even if it's on ANON LRU.
*/
if (PageAnon(page))
__this_cpu_add(memcg->stat->count[MEMCG_RSS], nr_pages);
__mod_memcg_state(memcg, MEMCG_RSS, nr_pages);
else {
__this_cpu_add(memcg->stat->count[MEMCG_CACHE], nr_pages);
__mod_memcg_state(memcg, MEMCG_CACHE, nr_pages);
if (PageSwapBacked(page))
__this_cpu_add(memcg->stat->count[NR_SHMEM], nr_pages);
__mod_memcg_state(memcg, NR_SHMEM, nr_pages);
}

if (compound) {
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
__this_cpu_add(memcg->stat->count[MEMCG_RSS_HUGE], nr_pages);
__mod_memcg_state(memcg, MEMCG_RSS_HUGE, nr_pages);
}

/* pagein of a big page is an event. So, ignore page size */
if (nr_pages > 0)
__this_cpu_inc(memcg->stat->events[PGPGIN]);
__count_memcg_events(memcg, PGPGIN, 1);
else {
__this_cpu_inc(memcg->stat->events[PGPGOUT]);
__count_memcg_events(memcg, PGPGOUT, 1);
nr_pages = -nr_pages; /* for event */
}

Expand Down Expand Up @@ -2415,18 +2415,11 @@ void mem_cgroup_split_huge_fixup(struct page *head)
for (i = 1; i < HPAGE_PMD_NR; i++)
head[i].mem_cgroup = head->mem_cgroup;

__this_cpu_sub(head->mem_cgroup->stat->count[MEMCG_RSS_HUGE],
HPAGE_PMD_NR);
__mod_memcg_state(head->mem_cgroup, MEMCG_RSS_HUGE, -HPAGE_PMD_NR);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifdef CONFIG_MEMCG_SWAP
static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
int nr_entries)
{
this_cpu_add(memcg->stat->count[MEMCG_SWAP], nr_entries);
}

/**
* mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
* @entry: swap entry to be moved
Expand All @@ -2450,8 +2443,8 @@ static int mem_cgroup_move_swap_account(swp_entry_t entry,
new_id = mem_cgroup_id(to);

if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
mem_cgroup_swap_statistics(from, -1);
mem_cgroup_swap_statistics(to, 1);
mod_memcg_state(from, MEMCG_SWAP, -1);
mod_memcg_state(to, MEMCG_SWAP, 1);
return 0;
}
return -EINVAL;
Expand Down Expand Up @@ -4584,8 +4577,8 @@ static int mem_cgroup_move_account(struct page *page,
spin_lock_irqsave(&from->move_lock, flags);

if (!anon && page_mapped(page)) {
__this_cpu_sub(from->stat->count[NR_FILE_MAPPED], nr_pages);
__this_cpu_add(to->stat->count[NR_FILE_MAPPED], nr_pages);
__mod_memcg_state(from, NR_FILE_MAPPED, -nr_pages);
__mod_memcg_state(to, NR_FILE_MAPPED, nr_pages);
}

/*
Expand All @@ -4597,16 +4590,14 @@ static int mem_cgroup_move_account(struct page *page,
struct address_space *mapping = page_mapping(page);

if (mapping_cap_account_dirty(mapping)) {
__this_cpu_sub(from->stat->count[NR_FILE_DIRTY],
nr_pages);
__this_cpu_add(to->stat->count[NR_FILE_DIRTY],
nr_pages);
__mod_memcg_state(from, NR_FILE_DIRTY, -nr_pages);
__mod_memcg_state(to, NR_FILE_DIRTY, nr_pages);
}
}

if (PageWriteback(page)) {
__this_cpu_sub(from->stat->count[NR_WRITEBACK], nr_pages);
__this_cpu_add(to->stat->count[NR_WRITEBACK], nr_pages);
__mod_memcg_state(from, NR_WRITEBACK, -nr_pages);
__mod_memcg_state(to, NR_WRITEBACK, nr_pages);
}

/*
Expand Down Expand Up @@ -5642,11 +5633,11 @@ static void uncharge_batch(const struct uncharge_gather *ug)
}

local_irq_save(flags);
__this_cpu_sub(ug->memcg->stat->count[MEMCG_RSS], ug->nr_anon);
__this_cpu_sub(ug->memcg->stat->count[MEMCG_CACHE], ug->nr_file);
__this_cpu_sub(ug->memcg->stat->count[MEMCG_RSS_HUGE], ug->nr_huge);
__this_cpu_sub(ug->memcg->stat->count[NR_SHMEM], ug->nr_shmem);
__this_cpu_add(ug->memcg->stat->events[PGPGOUT], ug->pgpgout);
__mod_memcg_state(ug->memcg, MEMCG_RSS, -ug->nr_anon);
__mod_memcg_state(ug->memcg, MEMCG_CACHE, -ug->nr_file);
__mod_memcg_state(ug->memcg, MEMCG_RSS_HUGE, -ug->nr_huge);
__mod_memcg_state(ug->memcg, NR_SHMEM, -ug->nr_shmem);
__count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
__this_cpu_add(ug->memcg->stat->nr_page_events, nr_pages);
memcg_check_events(ug->memcg, ug->dummy_page);
local_irq_restore(flags);
Expand Down Expand Up @@ -5874,7 +5865,7 @@ bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
if (in_softirq())
gfp_mask = GFP_NOWAIT;

this_cpu_add(memcg->stat->count[MEMCG_SOCK], nr_pages);
mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);

if (try_charge(memcg, gfp_mask, nr_pages) == 0)
return true;
Expand All @@ -5895,7 +5886,7 @@ void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
return;
}

this_cpu_sub(memcg->stat->count[MEMCG_SOCK], nr_pages);
mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);

refill_stock(memcg, nr_pages);
}
Expand Down Expand Up @@ -6019,7 +6010,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
nr_entries);
VM_BUG_ON_PAGE(oldid, page);
mem_cgroup_swap_statistics(swap_memcg, nr_entries);
mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);

page->mem_cgroup = NULL;

Expand Down Expand Up @@ -6085,7 +6076,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
mem_cgroup_id_get_many(memcg, nr_pages - 1);
oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
VM_BUG_ON_PAGE(oldid, page);
mem_cgroup_swap_statistics(memcg, nr_pages);
mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);

return 0;
}
Expand Down Expand Up @@ -6113,7 +6104,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
else
page_counter_uncharge(&memcg->memsw, nr_pages);
}
mem_cgroup_swap_statistics(memcg, -nr_pages);
mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
mem_cgroup_id_put_many(memcg, nr_pages);
}
rcu_read_unlock();
Expand Down

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