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Tue, 28 Jun 2022 09:08:20 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id wxFzIQTFumKKQAAAMHmgww (envelope-from ); Tue, 28 Jun 2022 09:08:20 +0000 Date: Tue, 28 Jun 2022 11:08:19 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Roman Gushchin Cc: Vasily Averin , Muchun Song , Shakeel Butt , Michal Hocko , kernel@openvz.org, LKML , Andrew Morton , Linux Memory Management List , Vlastimil Babka , Cgroups Subject: Re: [PATCH mm v2] memcg: notify about global mem_cgroup_id space depletion Message-ID: <20220628090819.GB30543@blackbody.suse.cz> References: <97bed1fd-f230-c2ea-1cb6-8230825a9a64@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656407302; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; 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dmarc=pass (policy=quarantine) header.from=suse.com X-Rspam-User: X-Rspamd-Server: rspam06 X-Stat-Signature: rnikqf9kpioib88rxu7d6s9jcpesdffk X-Rspamd-Queue-Id: 68D524002D X-HE-Tag: 1656407302-988937 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000143, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jun 27, 2022 at 06:11:27PM -0700, Roman Gushchin wrote: > I think a better approach will be to add a cgroup event (displayed via > cgroup.events) about reaching the maximum limit of cgroups. E.g. > cgroups.events::max_nr_reached. This sounds like a good generalization. > Then you can set cgroup.max.descendants to some value below memcg_id > space size. It's more work, but IMO it's a better way to communicate > this event. As a bonus, you can easily get an idea which cgroup > depletes the limit. Just mind there's a difference between events: what cgroup's limit was hit and what cgroup was affected by the limit [1] (the former is more useful for the calibration if I understand the situation). Michal [1] https://lore.kernel.org/all/20200205134426.10570-2-mkoutny@suse.com/