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 0C6A0C001DF for ; Wed, 2 Aug 2023 07:40:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9ED46280136; Wed, 2 Aug 2023 03:40:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 99CF7280112; Wed, 2 Aug 2023 03:40:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 88BEE280136; Wed, 2 Aug 2023 03:40:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 7AA76280112 for ; Wed, 2 Aug 2023 03:40:21 -0400 (EDT) Received: from smtpin20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 485B6120430 for ; Wed, 2 Aug 2023 07:40:21 +0000 (UTC) X-FDA: 81078366642.20.B384CEF Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf14.hostedemail.com (Postfix) with ESMTP id 360BD100005 for ; Wed, 2 Aug 2023 07:40:18 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=J+S11sgO; spf=pass (imf14.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1690962019; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=6e6GiqmpyVCzOwvyGHqSNXCNxBFa7aDIzwYUNSYMUSM=; b=zGHOW8y+vxETctXN7sm5M4KWMIZsSMgD9mwTVBgr7CYdHp+mimtJ759JbtHN03Lo9pmw0M GfMuORUQTGBIs8OwNpiUTSgCKdHiVUSYZlWreiR/LyUixmantIomUtKDDHoiukUGRdcLWy grCnnQBJlflvT8IsXKiWd/Rd09LLhHM= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1690962019; a=rsa-sha256; cv=none; b=byC8GW7XUhyi9zd9HAAH/iuCsxRtKzhBdaz6H1ROyCR2YrQiRe8QHwdmNsAM3jx8cZKRZ7 lVMG/5URhnhQw4014sGq02HEVCuEcb2YefDYqYVZ3Lw7DQM2TiP5h6lDwZLJfxL6FCRzvD scjJH/Ydsr+mGlyof3qJynyytTlIARI= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=J+S11sgO; spf=pass (imf14.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com 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-out2.suse.de (Postfix) with ESMTPS id 8A1631F749; Wed, 2 Aug 2023 07:40:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1690962017; 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=6e6GiqmpyVCzOwvyGHqSNXCNxBFa7aDIzwYUNSYMUSM=; b=J+S11sgO6aiS75myCJ8iLCSy282SRXv1ywdO5YwOTHEIVWLCWo+CmZolywZvDiekiULT7E vWy7yPZAHd+/5e7nl5xlTRsvC9Ke8RqcIZJSFGjS/fxw80Gp6IoVhZvIX5Ru4mir/H7nD1 u3KKzJjm5zGmBVBQNz63u0Wcjp13FkY= 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 6B3A513909; Wed, 2 Aug 2023 07:40:17 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id XYsOF2EIymQ9JwAAMHmgww (envelope-from ); Wed, 02 Aug 2023 07:40:17 +0000 Date: Wed, 2 Aug 2023 09:40:16 +0200 From: Michal Hocko To: Yosry Ahmed Cc: Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH v3] mm: memcg: use rstat for non-hierarchical stats Message-ID: References: <20230726153223.821757-1-yosryahmed@google.com> <20230726153223.821757-2-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: jcdod4ma8m8gw4aykn8bd6ha1ufnc5nh X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 360BD100005 X-Rspam-User: X-HE-Tag: 1690962018-430366 X-HE-Meta: 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 FCK6iHFE eKdcdisIwjQAQkO8PFDeZkDxjtHwcz6XQnIkyh84JaCpKqMBa2pCmwVKXNotcd/rEptoNPYciSg+RqgPf+/MHyWCsEsXm5oK+gMLnwnROKXLWexpG2eiS8b4Wo6A7oiMUXcMsBlj0x698Fj+/cyP/onZRxaZ4F4R8oGFlnkK0Y+yfS9s= 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: On Tue 01-08-23 10:29:39, Yosry Ahmed wrote: > On Tue, Aug 1, 2023 at 9:39 AM Yosry Ahmed wrote: [...] > > > Have you measured any potential regression for cgroup v2 which collects > > > all this data without ever using it (AFAICS)? > > > > I did not. I did not expect noticeable regressions given that all the > > extra work is done during flushing, which should mostly be done by the > > asynchronous worker, but can also happen in the stats reading context. > > Let me run the same script on cgroup v2 just in case and report back. > > A few runs on mm-unstable with this patch: > > # time cat /sys/fs/cgroup/cg*/memory.stat > /dev/null Is this really representative test to make? I would have expected the overhead would be mostly in mem_cgroup_css_rstat_flush (if it is visible at all of course). This would be more likely visible in all cpus busy situation (you can try heavy parallel kernel build from tmpfs for example). [...] > It looks like there are no regressions on cgroup v2 when reading the > stats. Please let me know if you want me to send a new version with > the cgroup v2 results as well in the commit log -- or I can just send > a new commit log. Whatever is easier for Andrew. Updating the changelog should be good enough. -- Michal Hocko SUSE Labs