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Date:   Mon, 30 May 2022 14:26:59 +0300
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From:   Vasily Averin <vvs@openvz.org>
Subject: [PATCH mm v3 8/9] memcg: enable accounting for allocations in
 alloc_fair_sched_group
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     kernel@openvz.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Shakeel Butt <shakeelb@google.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        =?UTF-8?Q?Michal_Koutn=c3=bd?= <mkoutny@suse.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Michal Hocko <mhocko@suse.com>,
        Muchun Song <songmuchun@bytedance.com>, cgroups@vger.kernel.org
References: <06505918-3b8a-0ad5-5951-89ecb510138e@openvz.org>
 <cover.1653899364.git.vvs@openvz.org>
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Precedence: bulk

Creating of each new cpu cgroup allocates two 512-bytes kernel objects
per CPU. This is especially important for cgroups shared parent memory
cgroup. In this scenario, on nodes with multiple processors, these
allocations become one of the main memory consumers.

Memory allocated during new cpu cgroup creation:
common part: 	~11Kb	+  318 bytes percpu
cpu cgroup:	~2.5Kb	+ 1036 bytes percpu

Accounting for this memory helps to avoid misuse inside memcg-limited
contianers.

Signed-off-by: Vasily Averin <vvs@openvz.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
---
 kernel/sched/fair.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8c5b74f66bd3..f4fc39d5aa4b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -11499,12 +11499,12 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
 
 	for_each_possible_cpu(i) {
 		cfs_rq = kzalloc_node(sizeof(struct cfs_rq),
-				      GFP_KERNEL, cpu_to_node(i));
+				      GFP_KERNEL_ACCOUNT, cpu_to_node(i));
 		if (!cfs_rq)
 			goto err;
 
 		se = kzalloc_node(sizeof(struct sched_entity_stats),
-				  GFP_KERNEL, cpu_to_node(i));
+				  GFP_KERNEL_ACCOUNT, cpu_to_node(i));
 		if (!se)
 			goto err_free_rq;
 
-- 
2.36.1