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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2012-01-12 17:18:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:05 -0800
commite94c8a9cbce1aee4af9e1285802785481b7f93c5 (patch)
tree14d496e62c2e8d59a8954ff10368d59d8dfaea03 /mm/huge_memory.c
parent6b208e3f6e35aa76d254c395bdcd984b17c6b626 (diff)
downloadop-kernel-dev-e94c8a9cbce1aee4af9e1285802785481b7f93c5.zip
op-kernel-dev-e94c8a9cbce1aee4af9e1285802785481b7f93c5.tar.gz
memcg: make mem_cgroup_split_huge_fixup() more efficient
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>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 36b3d98..db522e1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1207,6 +1207,8 @@ static void __split_huge_page_refcount(struct page *page)
/* prevent PageLRU to go away from under us, and freeze lru stats */
spin_lock_irq(&zone->lru_lock);
compound_lock(page);
+ /* complete memcg works before add pages to LRU */
+ mem_cgroup_split_huge_fixup(page);
for (i = 1; i < HPAGE_PMD_NR; i++) {
struct page *page_tail = page + i;
@@ -1278,7 +1280,6 @@ static void __split_huge_page_refcount(struct page *page)
BUG_ON(!PageDirty(page_tail));
BUG_ON(!PageSwapBacked(page_tail));
- mem_cgroup_split_huge_fixup(page, page_tail);
lru_add_page_tail(zone, page, page_tail);
}
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