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memcg: make mem_cgroup_split_huge_fixup() more efficient

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In split_huge_page(), mem_cgroup_split_huge_fixup() is called to handle
page_cgroup modifcations.  It takes move_lock_page_cgroup() and modifies
page_cgroup and LRU accounting jobs and called HPAGE_PMD_SIZE - 1 times.

But thinking again,
  - compound_lock() is held at move_accout...then, it's not necessary
    to take move_lock_page_cgroup().
  - LRU is locked and all tail pages will go into the same LRU as
    head is now on.
  - page_cgroup is contiguous in huge page range.

This patch fixes mem_cgroup_split_huge_fixup() as to be called once per
hugepage and reduce costs for spliting.

[akpm@linux-foundation.org: fix typo, per Michal]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki
2012-01-12 17:18:20 -08:00
committed by Linus Torvalds
parent 6b208e3f6e
commit e94c8a9cbc
3 changed files with 21 additions and 21 deletions
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5
include/linux/memcontrol.h
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@ -163,7 +163,7 @@ u64 mem_cgroup_get_limit(struct mem_cgroup *memcg);
void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail);
void mem_cgroup_split_huge_fixup(struct page *head);
#endif
#ifdef CONFIG_DEBUG_VM
@ -379,8 +379,7 @@ u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
return 0;
}
static inline void mem_cgroup_split_huge_fixup(struct page *head,
struct page *tail)
static inline void mem_cgroup_split_huge_fixup(struct page *head)
{
}