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From: Roman Gushchin <roman.gushchin@linux.dev>
To: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Muchun Song <songmuchun@bytedance.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] memcg: reduce size of memcg vmstats structures
Date: Wed, 7 Sep 2022 16:27:12 -0700	[thread overview]
Message-ID: <Yxko0AxuVO6oiN5M@P9FQF9L96D.corp.robot.car> (raw)
In-Reply-To: <20220907043537.3457014-4-shakeelb@google.com>

On Wed, Sep 07, 2022 at 04:35:37AM +0000, Shakeel Butt wrote:
> The struct memcg_vmstats and struct memcg_vmstats_percpu contains two
> arrays each for events of size NR_VM_EVENT_ITEMS which can be as large
> as 110. However the memcg v1 only uses 4 of those while memcg v2 uses
> 15. The union of both is 17. On a 64 bit system, we are wasting
> approximately ((110 - 17) * 8 * 2) * (nr_cpus + 1) bytes which is
> significant on large machines.
> 
> This patch reduces the size of the given structures by adding one
> indirection and only stores array of events which are actually used by
> the memcg code. With this patch, the size of memcg_vmstats has reduced
> from 2544 bytes to 1056 bytes while the size of memcg_vmstats_percpu has
> reduced from 2568 bytes to 1080 bytes.

This is pretty impressive!

Thank you, Shakeel!

Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
for the series.

Thanks!

  reply	other threads:[~2022-09-07 23:27 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-07  4:35 [PATCH 0/3] memcg: reduce memory overhead of memory cgroups Shakeel Butt
2022-09-07  4:35 ` [PATCH 1/3] memcg: extract memcg_vmstats from struct mem_cgroup Shakeel Butt
2022-09-09  0:26   ` Michal Koutný
2022-09-09 16:11     ` Shakeel Butt
2022-09-07  4:35 ` [PATCH 2/3] memcg: rearrange code Shakeel Butt
2022-09-07  4:35 ` [PATCH 3/3] memcg: reduce size of memcg vmstats structures Shakeel Butt
2022-09-07 23:27   ` Roman Gushchin [this message]
2022-09-08  2:35   ` Shakeel Butt
2022-09-08 22:37     ` Andrew Morton
2022-09-09  0:23   ` Michal Koutný
2022-09-09 17:14     ` Shakeel Butt

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