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From:   Shakeel Butt <shakeelb@google.com>
Date:   Sat, 21 May 2022 14:35:51 -0700
Message-ID: <CALvZod6qeh_rNVVpZ5N8RMauhvxjQ=wLJUpK-QBCa9AXDNqi_g@mail.gmail.com>
Subject: Re: [PATCH mm v2 6/9] memcg: enable accounting for percpu allocation
 of struct cgroup_rstat_cpu
To:     Vasily Averin <vvs@openvz.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>, kernel@openvz.org,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        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>,
        Cgroups <cgroups@vger.kernel.org>
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On Sat, May 21, 2022 at 9:38 AM Vasily Averin <vvs@openvz.org> wrote:
>
> struct cgroup_rstat_cpu is percpu allocated for each new cgroup and
> can consume a significant portion of all allocated memory on nodes
> with a large number of CPUs.
>
> Common part of the cgroup creation:
> Allocs  Alloc   $1*$2   Sum     Allocation
> number  size
> --------------------------------------------
> 16  ~   352     5632    5632    KERNFS
> 1   +   4096    4096    9728    (cgroup_mkdir+0xe4)
> 1       584     584     10312   (radix_tree_node_alloc.constprop.0+0x89)
> 1       192     192     10504   (__d_alloc+0x29)
> 2       72      144     10648   (avc_alloc_node+0x27)
> 2       64      128     10776   (percpu_ref_init+0x6a)
> 1       64      64      10840   (memcg_list_lru_alloc+0x21a)
> percpu:
> 1   +   192     192     192     call_site=psi_cgroup_alloc+0x1e
> 1   +   96      96      288     call_site=cgroup_rstat_init+0x5f
> 2       12      24      312     call_site=percpu_ref_init+0x23
> 1       6       6       318     call_site=__percpu_counter_init+0x22
>
>  '+' -- to be accounted,
>  '~' -- partially accounted
>
> Signed-off-by: Vasily Averin <vvs@openvz.org>

Acked-by: Shakeel Butt <shakeelb@google.com>