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b=iyiO+vuzRlgKW3K1+bkEDfNzcyr9AHOBWIzMxQ1JJ9NF+heBdAq0HOnL41UTjtTY8 FkidymqWCHajYKrqOO0SRueiqUsp3+mGTkOg1/h/g/92TfwnFYDheZUZRBpg0eMrdm 4FpCdLiozbcVSwj3Iwyeam4uS9XXt0v+SCn2uG6A= Date: Wed, 14 Oct 2026 13:50:46 -0700 From: Andrew Morton To: Konstantin Khorenko Cc: Dave Chinner , Qi Zheng , Roman Gushchin , Muchun Song , Johannes Weiner , Michal Hocko , Shakeel Butt , 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> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: EC51B100007 X-Rspam-User: X-Stat-Signature: phtt9ge3hizi8mzk3cojjhutrn64gato X-HE-Tag: 1792011047-416727 X-HE-Meta: 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 yRhJUy9R 936MdDtwHS+cUQIxj7EGhgrRNHtE0esGy0K8xJlAN+Y4SFhJXmcAa8NgW20USps0WkTLcXl3a06tp+oQ5VRgbyMt+hVf1nqUCjePw8RHEzQ/aE1mDAypk6SXMcvFEXE/zaOQ24ytEJ+RzazaQNWljm+cUaM0ehSBgGDkvlwVR/pHMBAbyBYaJL4EPf3BK1rhHK5J5ufwiXC9paq3Flf/ZceBb8pyQJrURJczO4XuH8sTsrt526VV6fstsDQ0p42hs4AkP2zMG2Pc+RG806+P6R5pZ/dCEkAS9C93EroxyBNuuSQnWxa7sOb9h9Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, 14 Oct 2026 16:54:36 +0200 Konstantin Khorenko 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?