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Fri, 04 Jun 2021 05:45:20 -0700 (PDT) Received: from localhost ([199.192.137.73]) by smtp.gmail.com with ESMTPSA id f11sm3375209qtf.30.2021.06.04.05.45.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Jun 2021 05:45:20 -0700 (PDT) Date: Fri, 4 Jun 2021 08:45:19 -0400 From: Tejun Heo To: Hillf Danton Cc: Shakeel Butt , Johannes Weiner , Muchun Song , Michal Hocko , Roman Gushchin , Michal =?iso-8859-1?Q?Koutn=FD?= , Huang Ying , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] memcg: periodically flush the memcg stats Message-ID: References: <20210604015640.2586269-1-shakeelb@google.com> <20210604061816.3110-1-hdanton@sina.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210604061816.3110-1-hdanton@sina.com> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 99AF1575 X-Stat-Signature: 8ym6r11c9n7esx8fk46i9innhthktsrp Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b="QOs7/5Iz"; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none); spf=pass (imf12.hostedemail.com: domain of htejun@gmail.com designates 209.85.160.169 as permitted sender) smtp.mailfrom=htejun@gmail.com X-HE-Tag: 1622810711-488539 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 Fri, Jun 04, 2021 at 02:18:16PM +0800, Hillf Danton wrote: > On Thu, 3 Jun 2021 18:56:40 -0700 Shakeel Butt wrote: > > > > +static void flush_memcg_stats(struct work_struct *w) > > +{ > > + cgroup_rstat_flush(root_mem_cgroup->css.cgroup); > > + schedule_delayed_work(&stats_flush, round_jiffies(2UL*HZ)); > > +} > > Given flush may block, the unbound wq is what you need. > > queue_delayed_work(system_unbound_wq, &stats_flush, 2 * HZ); Default per-cpu workqueue can block just fine. I don't see a strong reason why this would need to be unbound. -- tejun