diff options
| -rw-r--r-- | mm/memcontrol.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b495f29d4746..a0ae64ca55bf 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6157,7 +6157,12 @@ void mem_cgroup_migrate(struct page *oldpage, struct page *newpage, if (PageCgroupUsed(pc)) return; - /* Re-entrant migration: old page already uncharged? */ + /* + * Swapcache readahead pages can get migrated before being + * charged, and migration from compaction can happen to an + * uncharged page when the PFN walker finds a page that + * reclaim just put back on the LRU but has not released yet. + */ pc = lookup_page_cgroup(oldpage); if (!PageCgroupUsed(pc)) return; |