linux-kernel - [PATCH v2 1/2] memcg, oom: remove unnecessary check in mem_cgroup_oom

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Date:   Wed, 19 Apr 2023 03:07:38 +0000
From:   Haifeng Xu <haifeng.xu@...pee.com>
To:     mhocko@...e.com
Cc:     hannes@...xchg.org, roman.gushchin@...ux.dev, shakeelb@...gle.com,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Haifeng Xu <haifeng.xu@...pee.com>
Subject: [PATCH v2 1/2] memcg, oom: remove unnecessary check in mem_cgroup_oom_synchronize()

mem_cgroup_oom_synchronize() is only used when the memcg oom handling is
handed over to the edge of the #PF path. Since commit 29ef680ae7c2 ("memcg,
oom: move out_of_memory back to the charge path") this is the case only
when the kernel memcg oom killer is disabled (current->memcg_in_oom is
only set if memcg->oom_kill_disable). Therefore a check for
oom_kill_disable in mem_cgroup_oom_synchronize() is not required.

Signed-off-by: Haifeng Xu <haifeng.xu@...pee.com>
Suggested-by: Michal Hocko <mhocko@...e.com>
---
v2: split original into two and improve patch description
---
 mm/memcontrol.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5abffe6f8389..fbf4d2bb1003 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1999,16 +1999,9 @@ bool mem_cgroup_oom_synchronize(bool handle)
 	if (locked)
 		mem_cgroup_oom_notify(memcg);
 
-	if (locked && !memcg->oom_kill_disable) {
-		mem_cgroup_unmark_under_oom(memcg);
-		finish_wait(&memcg_oom_waitq, &owait.wait);
-		mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
-					 current->memcg_oom_order);
-	} else {
-		schedule();
-		mem_cgroup_unmark_under_oom(memcg);
-		finish_wait(&memcg_oom_waitq, &owait.wait);
-	}
+	schedule();
+	mem_cgroup_unmark_under_oom(memcg);
+	finish_wait(&memcg_oom_waitq, &owait.wait);
 
 	if (locked) {
 		mem_cgroup_oom_unlock(memcg);
-- 
2.25.1