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Thu, 20 Feb 2020 10:45:46 -0800 (PST) Received: from localhost ([2620:10d:c091:500::55b1]) by smtp.gmail.com with ESMTPSA id z1sm194156qtq.69.2020.02.20.10.45.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 10:45:45 -0800 (PST) Date: Thu, 20 Feb 2020 13:45:45 -0500 From: Tejun Heo To: Daniel Jordan Cc: Johannes Weiner , Michal Hocko , Andrew Morton , Roman Gushchin , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Peter Zijlstra Subject: Re: [PATCH] mm: memcontrol: asynchronous reclaim for memory.high Message-ID: <20200220184545.GH698990@mtj.thefacebook.com> References: <20200219181219.54356-1-hannes@cmpxchg.org> <20200219183731.GC11847@dhcp22.suse.cz> <20200219191618.GB54486@cmpxchg.org> <20200219195332.GE11847@dhcp22.suse.cz> <20200219214112.4kt573kyzbvmbvn3@ca-dmjordan1.us.oracle.com> <20200219220859.GF54486@cmpxchg.org> <20200220154524.dql3i5brnjjwecft@ca-dmjordan1.us.oracle.com> <20200220155651.GG698990@mtj.thefacebook.com> <20200220182326.ubcjycaubgykiy6e@ca-dmjordan1.us.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200220182326.ubcjycaubgykiy6e@ca-dmjordan1.us.oracle.com> 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: Hello, On Thu, Feb 20, 2020 at 01:23:26PM -0500, Daniel Jordan wrote: > The amount of work wouldn't seem to matter as long as the kernel thread stays > in the cgroup and lives long enough. There's only the one-time cost of > attaching it when it's forked. That seems doable for unbound workqueues (the > async reclaim), but may not be for the network packets. The setup cost can be lazy optimized but it'd still have to bounce the tiny pieces of work to different threads instead of processing them in one fell swoop from the same context, which most likely is gonna be untenably expensive. Thanks. -- tejun