From: "Michal Koutný" <mkoutny@suse.com>
To: "T.J. Mercier" <tjmercier@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeelb@google.com>,
Muchun Song <muchun.song@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Efly Young <yangyifei03@kuaishou.com>,
android-mm@google.com, yuzhao@google.com,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: memcg: Use larger chunks for proactive reclaim
Date: Thu, 1 Feb 2024 14:57:22 +0100 [thread overview]
Message-ID: <q3m42iuxahsjrskuio3ajz2edrisiw56cwy2etx2jyht5l7jzq@ttbsrvgu4mvl> (raw)
In-Reply-To: <20240131162442.3487473-1-tjmercier@google.com>
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Hello.
On Wed, Jan 31, 2024 at 04:24:41PM +0000, "T.J. Mercier" <tjmercier@google.com> wrote:
> reclaimed = try_to_free_mem_cgroup_pages(memcg,
> - min(nr_to_reclaim - nr_reclaimed, SWAP_CLUSTER_MAX),
> + max((nr_to_reclaim - nr_reclaimed) / 4,
> + (nr_to_reclaim - nr_reclaimed) % 4),
The 1/4 factor looks like magic.
Commit 0388536ac291 says:
| In theory, the amount of reclaimed would be in [request, 2 * request).
Doesn't this suggest 1/2 as a better option? (I didn't pursue the
theory.)
Also IMO importantly, when nr_to_reclaim - nr_reclaimed is less than 8,
the formula gives arbitrary (unrelated to delta's magnitude) values.
Regards,
Michal
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next prev parent reply other threads:[~2024-02-01 13:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-31 16:24 T.J. Mercier
2024-01-31 17:50 ` Johannes Weiner
2024-01-31 18:01 ` T.J. Mercier
2024-01-31 20:12 ` Johannes Weiner
2024-02-01 13:57 ` Michal Koutný [this message]
2024-02-01 15:34 ` Johannes Weiner
2024-02-01 18:10 ` T.J. Mercier
2024-02-02 5:02 ` Efly Young
2024-02-02 10:15 ` Michal Koutný
2024-02-02 18:22 ` T.J. Mercier
2024-02-02 19:46 ` Michal Koutný
2024-02-02 21:42 ` T.J. Mercier
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