The patch titled
Subject: memcg: remove unnecessary thp check in page stat accounting
has been added to the -mm tree. Its filename is
memcg-remove-unnecessary-thp-check-in-page-stat-accounting.patch
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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Subject: memcg: remove unnecessary thp check in page stat accounting
e94c8a9cbce1ae ("memcg: make mem_cgroup_split_huge_fixup() more
efficient") removed move_lock_page_cgroup(). So we do not have to check
PageTransHuge in mem_cgroup_update_page_stat() and fallback into the
locked accounting because both move_account() and thp split are done with
compound_lock so they cannot race.
The race between update vs. move is protected by mem_cgroup_stealed.
PageTransHuge pages shouldn't appear in this code path currently because
we are tracking only file pages at the moment but later we are planning
to track also other pages (e.g. mlocked ones).
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Reviewed-by: Acked-by: Michal Hocko <mhocko@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/memcontrol.c~memcg-remove-unnecessary-thp-check-in-page-stat-accounting mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-remove-unnecessary-thp-check-in-page-stat-accounting
+++ a/mm/memcontrol.c
@@ -1864,7 +1864,7 @@ void mem_cgroup_update_page_stat(struct
if (unlikely(!memcg || !PageCgroupUsed(pc)))
goto out;
/* pc->mem_cgroup is unstable ? */
- if (unlikely(mem_cgroup_stealed(memcg)) || PageTransHuge(page)) {
+ if (unlikely(mem_cgroup_stealed(memcg))) {
/* take a lock against to access pc->mem_cgroup */
move_lock_page_cgroup(pc, &flags);
need_unlock = true;
_
Subject: Subject: memcg: remove unnecessary thp check in page stat accounting
Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are
mm-fix-null-ptr-dereference-in-__count_immobile_pages.patch
mm-__count_immobile_pages-make-sure-the-node-is-online.patch
mm-memcg-update-the-correct-soft-limit-tree-during-migration.patch
mm-hugetlb-undo-change-to-page-mapcount-in-fault-handler.patch
mm-fix-rss-count-leakage-during-migration.patch
mm-oom-avoid-looping-when-chosen-thread-detaches-its-mm.patch
mm-oom-fold-oom_kill_task-into-oom_kill_process.patch
mm-oom-do-not-emit-oom-killer-warning-if-chosen-thread-is-already-exiting.patch
mm-add-rss-counters-consistency-check.patch
mm-postpone-migrated-page-mapping-reset.patch
mm-vmscanc-cleanup-with-s-reclaim_mode-isolate_mode.patch
mm-make-get_mm_counter-static-inline.patch
memcg-replace-mem_cont-by-mem_res_ctlr.patch
memcg-replace-mem-and-mem_cont-stragglers.patch
memcg-lru_size-instead-of-mem_cgroup_zstat.patch
memcg-enum-lru_list-lru.patch
memcg-remove-redundant-returns.patch
memcg-remove-unnecessary-thp-check-in-page-stat-accounting.patch
proc-speedup-proc-stat-handling.patch
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