path: root/mm/ksm.c
diff options
authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2012-01-12 17:18:58 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-12 20:13:07 -0800
commit4e5f01c2b9b94321992acb09c35d34f5ee5bb274 (patch)
tree4e6ac9d29539dc26468fe2630d0e64cd022b1155 /mm/ksm.c
parentmemcg: simplify corner case handling of LRU. (diff)
memcg: clear pc->mem_cgroup if necessary.
This is a preparation before removing a flag PCG_ACCT_LRU in page_cgroup and reducing atomic ops/complexity in memcg LRU handling. In some cases, pages are added to lru before charge to memcg and pages are not classfied to memory cgroup at lru addtion. Now, the lru where the page should be added is determined a bit in page_cgroup->flags and pc->mem_cgroup. I'd like to remove the check of flag. To handle the case pc->mem_cgroup may contain stale pointers if pages are added to LRU before classification. This patch resets pc->mem_cgroup to root_mem_cgroup before lru additions. [akpm@linux-foundation.org: fix CONFIG_CGROUP_MEM_CONT=n build] [hughd@google.com: fix CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_CGROUP_MEM_RES_CTLR_SWAP=n build] [akpm@linux-foundation.org: ksm.c needs memcontrol.h, per Michal] [hughd@google.com: stop oops in mem_cgroup_reset_owner()] [hughd@google.com: fix page migration to reset_owner] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 310544a379ae..1925ffbfb27f 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -28,6 +28,7 @@
#include <linux/kthread.h>
#include <linux/wait.h>
#include <linux/slab.h>
+#include <linux/memcontrol.h>
#include <linux/rbtree.h>
#include <linux/memory.h>
#include <linux/mmu_notifier.h>
@@ -1571,6 +1572,16 @@ struct page *ksm_does_need_to_copy(struct page *page,
new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
if (new_page) {
+ /*
+ * The memcg-specific accounting when moving
+ * pages around the LRU lists relies on the
+ * page's owner (memcg) to be valid. Usually,
+ * pages are assigned to a new owner before
+ * being put on the LRU list, but since this
+ * is not the case here, the stale owner from
+ * a previous allocation cycle must be reset.
+ */
+ mem_cgroup_reset_owner(new_page);
copy_user_highpage(new_page, page, address, vma);