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 BBC5AC761AF for ; Thu, 30 Mar 2023 07:43:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 476906B0072; Thu, 30 Mar 2023 03:43:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 427076B0074; Thu, 30 Mar 2023 03:43:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2EEF86B0075; Thu, 30 Mar 2023 03:43:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 1C93A6B0072 for ; Thu, 30 Mar 2023 03:43:47 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id ED570C0C9B for ; Thu, 30 Mar 2023 07:43:46 +0000 (UTC) X-FDA: 80624775252.11.6E3A7B3 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf09.hostedemail.com (Postfix) with ESMTP id 0CAA4140025 for ; Thu, 30 Mar 2023 07:43:44 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=MVEtG58M; spf=pass (imf09.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1680162225; a=rsa-sha256; cv=none; b=41LtRvZEYLzM7xH6XSU7Vt3l9/BnA6JWMq7jCaOxKs7Jf756g+nBMKND4+vs4f7HKsfjGi W53Founa0vvdJf426QbN1+41jnwtBiPJ2L0ySJjjd33M/AYX+WeZRK+np+rS0HbPjkyK9n R4i9cCwuo5N0KeVrirbTA6RZAPy9Cus= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=MVEtG58M; spf=pass (imf09.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 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=1680162225; 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; bh=pcR6uGA8qbqfio6LsBj8cNALnv9xWak5dIIrh+CRcYc=; b=3TaW85BdrVVDrVx+LTMC/MhdJqO8y5lwoKC2TSpGfixrLXiSUN2SvvMQEjbvpasybUexiD QxpV1J7LdxnI/lV5rtIuQfSphXWJ6MqE4YfXtvLfLcHi34KWiTr7JQw4VP+RtlxNUTBtWX 6YS+kqfdZJMV1PakjVHsMJJEmumOSLg= 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 C112F21B04; Thu, 30 Mar 2023 07:43:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1680162223; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=pcR6uGA8qbqfio6LsBj8cNALnv9xWak5dIIrh+CRcYc=; b=MVEtG58MeLA15yiqwOQsyU7lQWKy3SM6ILJww5NxO11VDo5w2GI08CrM66fX87jUm+ZTrn WGtLRJH21MUpLoK6nzD4jfvLVEN2izyrVTfW4vT2qm3ipGVANV5+V6S+CWgIy3tcl7vMO0 JYW0mU18y8N5KC2JpW6dUF5XhrBC/cg= 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 A02691348E; Thu, 30 Mar 2023 07:43:43 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id yz7ZJK89JWR2fgAAMHmgww (envelope-from ); Thu, 30 Mar 2023 07:43:43 +0000 Date: Thu, 30 Mar 2023 09:43:42 +0200 From: Michal Hocko To: Yosry Ahmed Cc: Tejun Heo , Josef Bacik , Jens Axboe , Zefan Li , Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , Michal =?iso-8859-1?Q?Koutn=FD?= , Vasily Averin , cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org Subject: Re: [PATCH v2 9/9] memcg: do not modify rstat tree for zero updates Message-ID: References: <20230328221644.803272-1-yosryahmed@google.com> <20230328221644.803272-10-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230328221644.803272-10-yosryahmed@google.com> X-Rspam-User: X-Rspamd-Queue-Id: 0CAA4140025 X-Rspamd-Server: rspam01 X-Stat-Signature: x8gzaoop61jx6jmjxaf77ypy4rxp4k4d X-HE-Tag: 1680162224-842062 X-HE-Meta: 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 bmwAwOp5 dbtkUrSBGLXv3STT7vbBlEC9QJPI6E2Ema0lPDMubHlVDs6P9/ls0Hf0rCLwHGuGQ85+0pHyXKH8F15Kj4/E4AIdkYzIMroZtYbV1LYTJwGF8wbghhd4uGeEitqA8a4MpuRpEg59CPM37cWrwjy1reso/19592DP7DDMDgeWUAl4vxYDQ9xjbYqM1yMQVpGDwp2d5390MY7fWKsHw/FkJwbv3ppi8o5R6qKgq1S7Yq/4rFOp91tpe15EG4RQQWv9NLhdzLAWpyqdaJyE02p6nqXK85T/vWuS312EZZmRO3CljYm5qTRYVakAeGw== 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 28-03-23 22:16:44, Yosry Ahmed wrote: > In some situations, we may end up calling memcg_rstat_updated() with a > value of 0, which means the stat was not actually updated. An example is > if we fail to reclaim any pages in shrink_folio_list(). > > Do not add the cgroup to the rstat updated tree in this case, to avoid > unnecessarily flushing it. > > Signed-off-by: Yosry Ahmed > Acked-by: Shakeel Butt > Acked-by: Johannes Weiner Acked-by: Michal Hocko > --- > mm/memcontrol.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 361c0bbf7283..a63ee2efa780 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -618,6 +618,9 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val) > { > unsigned int x; > > + if (!val) > + return; > + > cgroup_rstat_updated(memcg->css.cgroup, smp_processor_id()); > > x = __this_cpu_add_return(stats_updates, abs(val)); > -- > 2.40.0.348.gf938b09366-goog -- Michal Hocko SUSE Labs