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-rw-r--r--mm/memcontrol.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 4f71219cc53e..d7ce417cae7c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3373,7 +3373,7 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg,
void mem_cgroup_replace_page_cache(struct page *oldpage,
struct page *newpage)
{
- struct mem_cgroup *memcg;
+ struct mem_cgroup *memcg = NULL;
struct page_cgroup *pc;
enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
@@ -3383,11 +3383,20 @@ void mem_cgroup_replace_page_cache(struct page *oldpage,
pc = lookup_page_cgroup(oldpage);
/* fix accounting on old pages */
lock_page_cgroup(pc);
- memcg = pc->mem_cgroup;
- mem_cgroup_charge_statistics(memcg, false, -1);
- ClearPageCgroupUsed(pc);
+ if (PageCgroupUsed(pc)) {
+ memcg = pc->mem_cgroup;
+ mem_cgroup_charge_statistics(memcg, false, -1);
+ ClearPageCgroupUsed(pc);
+ }
unlock_page_cgroup(pc);
+ /*
+ * When called from shmem_replace_page(), in some cases the
+ * oldpage has already been charged, and in some cases not.
+ */
+ if (!memcg)
+ return;
+
if (PageSwapBacked(oldpage))
type = MEM_CGROUP_CHARGE_TYPE_SHMEM;