The patch titled Subject: mm: memcontrol: do not acquire page_cgroup lock for kmem pages has been removed from the -mm tree. Its filename was mm-memcontrol-do-not-acquire-page_cgroup-lock-for-kmem-pages.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Johannes Weiner <hannes@xxxxxxxxxxx> Subject: mm: memcontrol: do not acquire page_cgroup lock for kmem pages Kmem page charging and uncharging is serialized by means of exclusive access to the page. Do not take the page_cgroup lock and don't set pc->flags atomically. Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxx> Acked-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) diff -puN mm/memcontrol.c~mm-memcontrol-do-not-acquire-page_cgroup-lock-for-kmem-pages mm/memcontrol.c --- a/mm/memcontrol.c~mm-memcontrol-do-not-acquire-page_cgroup-lock-for-kmem-pages +++ a/mm/memcontrol.c @@ -3407,12 +3407,13 @@ void __memcg_kmem_commit_charge(struct p memcg_uncharge_kmem(memcg, PAGE_SIZE << order); return; } - + /* + * The page is freshly allocated and not visible to any + * outside callers yet. Set up pc non-atomically. + */ pc = lookup_page_cgroup(page); - lock_page_cgroup(pc); pc->mem_cgroup = memcg; - SetPageCgroupUsed(pc); - unlock_page_cgroup(pc); + pc->flags = PCG_USED; } void __memcg_kmem_uncharge_pages(struct page *page, int order) @@ -3422,19 +3423,11 @@ void __memcg_kmem_uncharge_pages(struct pc = lookup_page_cgroup(page); - /* - * Fast unlocked return. Theoretically might have changed, have to - * check again after locking. - */ if (!PageCgroupUsed(pc)) return; - lock_page_cgroup(pc); - if (PageCgroupUsed(pc)) { - memcg = pc->mem_cgroup; - ClearPageCgroupUsed(pc); - } - unlock_page_cgroup(pc); + memcg = pc->mem_cgroup; + pc->flags = 0; /* * We trust that only if there is a memcg associated with the page, it _ Patches currently in -mm which might be from hannes@xxxxxxxxxxx are origin.patch mm-memcontrol-rewrite-charge-api.patch mm-memcontrol-rewrite-uncharge-api.patch mm-memcontrol-use-page-lists-for-uncharge-batching.patch mm-memcontrol-use-page-lists-for-uncharge-batching-fix-hugetlb-page-lru.patch page-cgroup-trivial-cleanup.patch page-cgroup-get-rid-of-nr_pcg_flags.patch memcg-remove-lookup_cgroup_page-prototype.patch mm-memcontrol-avoid-charge-statistics-churn-during-page-migration.patch nilfs2-integrate-sysfs-support-into-driver-fix.patch linux-next.patch debugging-keep-track-of-page-owners.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html