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| author | Hugh Dickins <hughd@google.com> | 2012-01-13 05:19:52 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-13 08:13:09 +0400 |
| commit | 12d27107867fc7216e8faaff0b894b0f162dcf75 (patch) | |
| tree | 8f35d39f7e5d0b0f0ba10a3475e9fa4a2581e509 /mm/huge_memory.c | |
| parent | 0cee34fd72c582b4f8ad8ce00645b75fb4168199 (diff) | |
| download | linux-12d27107867fc7216e8faaff0b894b0f162dcf75.tar.xz | |
memcg: fix split_huge_page_refcounts()
This patch started off as a cleanup: __split_huge_page_refcounts() has to
cope with two scenarios, when the hugepage being split is already on LRU,
and when it is not; but why does it have to split that accounting across
three different sites? Consolidate it in lru_add_page_tail(), handling
evictable and unevictable alike, and use standard add_page_to_lru_list()
when accounting is needed (when the head is not yet on LRU).
But a recent regression in -next, I guess the removal of PageCgroupAcctLRU
test from mem_cgroup_split_huge_fixup(), makes this now a necessary fix:
under load, the MEM_CGROUP_ZSTAT count was wrapping to a huge number,
messing up reclaim calculations and causing a freeze at rmdir of cgroup.
Add a VM_BUG_ON to mem_cgroup_lru_del_list() when we're about to wrap that
count - this has not been the only such incident. Document that
lru_add_page_tail() is for Transparent HugePages by #ifdef around it.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
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.c | 10 |
1 files changed, 0 insertions, 10 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 76cc3f7dd4f0..b3ffc21ce801 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1229,7 +1229,6 @@ static void __split_huge_page_refcount(struct page *page) { int i; struct zone *zone = page_zone(page); - int zonestat; int tail_count = 0; /* prevent PageLRU to go away from under us, and freeze lru stats */ @@ -1317,15 +1316,6 @@ static void __split_huge_page_refcount(struct page *page) __dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES); __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); - /* - * A hugepage counts for HPAGE_PMD_NR pages on the LRU statistics, - * so adjust those appropriately if this page is on the LRU. - */ - if (PageLRU(page)) { - zonestat = NR_LRU_BASE + page_lru(page); - __mod_zone_page_state(zone, zonestat, -(HPAGE_PMD_NR-1)); - } - ClearPageCompound(page); compound_unlock(page); spin_unlock_irq(&zone->lru_lock); |