From a53f311349ca967b481f73501df5dfabb47a1d2f Mon Sep 17 00:00:00 2001 From: Kairui Song Date: Wed, 18 Dec 2024 19:46:30 +0800 Subject: [PATCH] mm, memcontrol: avoid duplicated memcg enable check Patch series "mm/swap_cgroup: remove global swap cgroup lock", v3. This series removes the global swap cgroup lock. The critical section of this lock is very short but it's still a bottle neck for mass parallel swap workloads. Up to 10% performance gain for tmpfs build kernel test on a 48c96t system under memory pressure, and no regression for other cases: This patch (of 3): mem_cgroup_uncharge_swap() includes a mem_cgroup_disabled() check, so the caller doesn't need to check that. Link: https://lkml.kernel.org/r/20241218114633.85196-1-ryncsn@gmail.com Link: https://lkml.kernel.org/r/20241218114633.85196-2-ryncsn@gmail.com Signed-off-by: Kairui Song Reviewed-by: Yosry Ahmed Reviewed-by: Roman Gushchin Acked-by: Shakeel Butt Acked-by: Chris Li Cc: Barry Song Cc: Hugh Dickins Cc: Johannes Weiner Cc: Michal Hocko Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7ddbb2d12eb9..5c373d275e7a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4595,7 +4595,7 @@ void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) * correspond 1:1 to page and swap slot lifetimes: we charge the * page to memory here, and uncharge swap when the slot is freed. */ - if (!mem_cgroup_disabled() && do_memsw_account()) { + if (do_memsw_account()) { /* * The swap entry might not get freed for a long time, * let's not wait for it. The page already received a