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authorJohannes Weiner <hannes@cmpxchg.org>2012-07-31 16:45:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-31 18:42:48 -0700
commit0030f535a5cf9b1841d2088c10a0b2f8f2987460 (patch)
tree5a71a5057fb0d3e1b5f22c550c4374ea709ac3bc /include
parent737449236240e30a7bbe99f4d5586b8ed1416763 (diff)
downloadlinux-0030f535a5cf9b1841d2088c10a0b2f8f2987460.tar.bz2
mm: memcg: fix compaction/migration failing due to memcg limits
Compaction (and page migration in general) can currently be hindered through pages being owned by memory cgroups that are at their limits and unreclaimable. The reason is that the replacement page is being charged against the limit while the page being replaced is also still charged. But this seems unnecessary, given that only one of the two pages will still be in use after migration finishes. This patch changes the memcg migration sequence so that the replacement page is not charged. Whatever page is still in use after successful or failed migration gets to keep the charge of the page that was going to be replaced. The replacement page will still show up temporarily in the rss/cache statistics, this can be fixed in a later patch as it's less urgent. Reported-by: David Rientjes <rientjes@google.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Wanpeng Li <liwp.linux@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/memcontrol.h11
1 files changed, 5 insertions, 6 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 5a3ee6423634..8d9489fdab2e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -98,9 +98,9 @@ int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
-extern int
-mem_cgroup_prepare_migration(struct page *page,
- struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask);
+extern void
+mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
+ struct mem_cgroup **memcgp);
extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
struct page *oldpage, struct page *newpage, bool migration_ok);
@@ -276,11 +276,10 @@ static inline struct cgroup_subsys_state
return NULL;
}
-static inline int
+static inline void
mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
- struct mem_cgroup **memcgp, gfp_t gfp_mask)
+ struct mem_cgroup **memcgp)
{
- return 0;
}
static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,