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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD5FEC433E6 for ; Tue, 16 Mar 2021 09:30:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 364AE6500F for ; Tue, 16 Mar 2021 09:30:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 364AE6500F Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 90A136B006C; Tue, 16 Mar 2021 05:30:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8BB986B006E; Tue, 16 Mar 2021 05:30:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7A9396B0070; Tue, 16 Mar 2021 05:30:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0114.hostedemail.com [216.40.44.114]) by kanga.kvack.org (Postfix) with ESMTP id 601C66B006C for ; Tue, 16 Mar 2021 05:30:58 -0400 (EDT) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 1C5878249980 for ; Tue, 16 Mar 2021 09:30:58 +0000 (UTC) X-FDA: 77925218196.16.D183545 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf08.hostedemail.com (Postfix) with ESMTP id 7D3B5801916A for ; Tue, 16 Mar 2021 09:30:57 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1615887056; 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=lBGk+Iyq4CVjb4mLe0kBH+gokhgg7ZND2EOk7K2C61E=; b=JlKA6J2mMwOl6dNyPKwczKNqW5ujsCX/JNcnjD9w/a3KbTDxWdeRveY6v+nSQvzPy7cTga 3jKZunIC3Fc8DEWQ6ZbMVPbPVTw1NjyL651SN0ROIRokZhD4hOlgVvuTLtujB+qwZOCFh+ dXNnU/vEJ9SzwTymxFR0IdP57NeyXro= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 174C7AC5C; Tue, 16 Mar 2021 09:30:56 +0000 (UTC) Date: Tue, 16 Mar 2021 10:30:54 +0100 From: Michal Hocko To: Johannes Weiner Cc: Andrew Morton , Roman Gushchin , Shakeel Butt , Tejun Heo , Michal =?iso-8859-1?Q?Koutn=FD?= , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH] mm: memcontrol: switch to rstat fix Message-ID: References: <20210315234100.64307-1-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210315234100.64307-1-hannes@cmpxchg.org> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 7D3B5801916A X-Stat-Signature: dww7jno3ecd7gnbpojdz74c56f3xo3p5 Received-SPF: none (suse.com>: No applicable sender policy available) receiver=imf08; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615887057-901616 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 Mon 15-03-21 19:41:00, Johannes Weiner wrote: > Fix a sleep in atomic section problem: wb_writeback() takes a spinlock > and calls wb_over_bg_thresh() -> mem_cgroup_wb_stats, but the regular > rstat flushing function called from in there does lockbreaking and may > sleep. Switch to the atomic variant, cgroup_rstat_irqsafe(). > > To be consistent with other memcg flush calls, but without adding > another memcg wrapper, inline and drop memcg_flush_vmstats() instead. > > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko > --- > mm/memcontrol.c | 15 +++++---------- > 1 file changed, 5 insertions(+), 10 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index f7fb12d3c2fc..9091913ec877 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -757,11 +757,6 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) > return mz; > } > > -static void memcg_flush_vmstats(struct mem_cgroup *memcg) > -{ > - cgroup_rstat_flush(memcg->css.cgroup); > -} > - > /** > * __mod_memcg_state - update cgroup memory statistics > * @memcg: the memory cgroup > @@ -1572,7 +1567,7 @@ static char *memory_stat_format(struct mem_cgroup *memcg) > * > * Current memory state: > */ > - memcg_flush_vmstats(memcg); > + cgroup_rstat_flush(memcg->css.cgroup); > > for (i = 0; i < ARRAY_SIZE(memory_stats); i++) { > u64 size; > @@ -3523,7 +3518,7 @@ static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) > unsigned long val; > > if (mem_cgroup_is_root(memcg)) { > - memcg_flush_vmstats(memcg); > + cgroup_rstat_flush(memcg->css.cgroup); > val = memcg_page_state(memcg, NR_FILE_PAGES) + > memcg_page_state(memcg, NR_ANON_MAPPED); > if (swap) > @@ -3925,7 +3920,7 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v) > int nid; > struct mem_cgroup *memcg = mem_cgroup_from_seq(m); > > - memcg_flush_vmstats(memcg); > + cgroup_rstat_flush(memcg->css.cgroup); > > for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { > seq_printf(m, "%s=%lu", stat->name, > @@ -3997,7 +3992,7 @@ static int memcg_stat_show(struct seq_file *m, void *v) > > BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats)); > > - memcg_flush_vmstats(memcg); > + cgroup_rstat_flush(memcg->css.cgroup); > > for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { > unsigned long nr; > @@ -4500,7 +4495,7 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages, > struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css); > struct mem_cgroup *parent; > > - memcg_flush_vmstats(memcg); > + cgroup_rstat_flush_irqsafe(memcg->css.cgroup); > > *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY); > *pwriteback = memcg_page_state(memcg, NR_WRITEBACK); > -- > 2.30.1 -- Michal Hocko SUSE Labs