+ mm-memcontrol-use-memcg_kmem_enabled-in-count_objcg_event.patch added to mm-unstable branch

+ mm-memcontrol-use-memcg_kmem_enabled-in-count_objcg_event.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: memcontrol: use memcg_kmem_enabled in count_objcg_event
has been added to the -mm mm-unstable branch.  Its filename is
     mm-memcontrol-use-memcg_kmem_enabled-in-count_objcg_event.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcontrol-use-memcg_kmem_enabled-in-count_objcg_event.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Kairui Song <kasong@tencent.com>
Subject: mm: memcontrol: use memcg_kmem_enabled in count_objcg_event
Date: Tue, 20 Sep 2022 02:06:33 +0800

Patch series "mm: memcontrol: cleanup and optimize for two accounting
params", v2.


This patch (of 2):

There are currently two helpers for checking if cgroup kmem
accounting is enabled:

- mem_cgroup_kmem_disabled
- memcg_kmem_enabled

mem_cgroup_kmem_disabled is a simple helper that returns true
if cgroup.memory=nokmem is specified, otherwise returns false.

memcg_kmem_enabled is a bit different, it returns true if
cgroup.memory=nokmem is not specified and there was at least one
non-root memory control enabled cgroup ever created. This help improve
performance when kmem accounting was not actually activated. And it's
optimized with static branch.

The usage of mem_cgroup_kmem_disabled is for sub-systems that need to
preallocate data for kmem accounting since they could be initialized
before kmem accounting is activated. But count_objcg_event doesn't
need that, so using memcg_kmem_enabled is better here.

Link: https://lkml.kernel.org/r/20220919180634.45958-1-ryncsn@gmail.com
Link: https://lkml.kernel.org/r/20220919180634.45958-2-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/include/linux/memcontrol.h~mm-memcontrol-use-memcg_kmem_enabled-in-count_objcg_event
+++ a/include/linux/memcontrol.h
@@ -1778,7 +1778,7 @@ static inline void count_objcg_event(str
 {
 	struct mem_cgroup *memcg;
 
-	if (mem_cgroup_kmem_disabled())
+	if (!memcg_kmem_enabled())
 		return;
 
 	rcu_read_lock();
_

Patches currently in -mm which might be from kasong@tencent.com are

mm-memcontrol-use-memcg_kmem_enabled-in-count_objcg_event.patch
mm-memcontrol-make-cgroup_memory_noswap-a-static-key.patch