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Date: Wed, 14 Oct 2026 13:50:46 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Konstantin Khorenko <khorenko@virtuozzo.com>
Cc: Dave Chinner <david@fromorbit.com>, Qi Zheng <qi.zheng@linux.dev>, Roman
 Gushchin <roman.gushchin@linux.dev>, Muchun Song <muchun.song@linux.dev>,
 Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@kernel.org>,
 Shakeel Butt <shakeel.butt@linux.dev>, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, cgroups@vger.kernel.org
Subject: Re: [PATCH v2 0/2] mm/shrinker: make per-memcg shrinker units
 cheaper
Message-Id: <20261014135046.7b13252ce99d918ffcdb1f49@linux-foundation.org>
In-Reply-To: <20261014-b4-prep-vstor-144715-size-shrinker_info_unit-to-a-power-of-two-v2-0-51af2aedbe6c@virtuozzo.com>
References: <20261014-b4-prep-vstor-144715-size-shrinker_info_unit-to-a-power-of-two-v2-0-51af2aedbe6c@virtuozzo.com>
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On Wed, 14 Oct 2026 16:54:36 +0200 Konstantin Khorenko <khorenko@virtuozzo.com> wrote:

> Every memory cgroup allocates, per NUMA node, one shrinker_info_unit
> per 64 memcg-aware shrinker ids up to shrinker_nr_max, whether or not it
> ever charges an object to those shrinkers. Every superblock registers
> such a shrinker, so the cost is
> 
>   memory cgroups x NUMA nodes x shrinker_nr_max / 64 x 1 KiB
> 
> because the unit is 520 bytes and comes from kmalloc-1k.

So we could almost halve this just by using a dedicated kmem_cache?