From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6BA63C433F5 for ; Wed, 11 May 2022 17:50:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B4D496B0073; Wed, 11 May 2022 13:50:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AFE2A6B0074; Wed, 11 May 2022 13:50:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9A2616B0075; Wed, 11 May 2022 13:50:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 8B3786B0073 for ; Wed, 11 May 2022 13:50:02 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 4FDC860B11 for ; Wed, 11 May 2022 17:49:57 +0000 (UTC) X-FDA: 79454200434.14.DFDCE6A Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf04.hostedemail.com (Postfix) with ESMTP id 85F9D400AB for ; Wed, 11 May 2022 17:49:46 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 79D5E21D24; Wed, 11 May 2022 17:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652291395; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hybTl5KXVmOatuBKIZ1j2DSZPawKaxXgyyz91XdUDuE=; b=G2bilHY0B/+vLx83jRgBB8ceum/Xr8F2UCoGFzvV/mo+XEiTGAAMpYAd2AhTxSY08pdrPp U4m58yO/rWjGFseMxnSsTzChDwtKo1EgEw2EgP72eymTewrYpBFvVPE7f1l89TA5jchVXT 1HvBpkMoA9W/gjRqjz5I3aT3F035XDE= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 522EB139F9; Wed, 11 May 2022 17:49:55 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id hj0JE0P3e2LtawAAMHmgww (envelope-from ); Wed, 11 May 2022 17:49:55 +0000 Date: Wed, 11 May 2022 19:49:54 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Ganesan Rajagopal Cc: hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v2] mm/memcontrol: Export memcg->watermark via sysfs for v2 memcg Message-ID: <20220511174953.GC31592@blackbody.suse.cz> References: <20220507050916.GA13577@us192.sjc.aristanetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220507050916.GA13577@us192.sjc.aristanetworks.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-Stat-Signature: kg9ybqt3hdrxy7hog6skk4kfj9krm6ka X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 85F9D400AB Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=G2bilHY0; spf=pass (imf04.hostedemail.com: domain of mkoutny@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mkoutny@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com X-Rspam-User: X-HE-Tag: 1652291386-737255 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi. On Fri, May 06, 2022 at 10:09:16PM -0700, Ganesan Rajagopal wrote: > We run a lot of automated tests when building our software and run into > OOM scenarios when the tests run unbounded. v1 memcg exports > memcg->watermark as "memory.max_usage_in_bytes" in sysfs. We use this > metric to heuristically limit the number of tests that can run in > parallel based on per test historical data. > > This metric is currently not exported for v2 memcg and there is no > other easy way of getting this information. getrusage() syscall returns > "ru_maxrss" which can be used as an approximation but that's the max > RSS of a single child process across all children instead of the > aggregated max for all child processes. The only work around is to > periodically poll "memory.current" but that's not practical for > short-lived one-off cgroups. > > Hence, expose memcg->watermark as "memory.peak" for v2 memcg. It'll save some future indirections if the commit messages includes the argument about multiple readers and purposeful irresetability. > > Signed-off-by: Ganesan Rajagopal > --- > Documentation/admin-guide/cgroup-v2.rst | 7 +++++++ > mm/memcontrol.c | 13 +++++++++++++ > 2 files changed, 20 insertions(+) Besides that it looks useful and correct, feel free to add Reviewed-by: Michal Koutný