From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933498AbeALMYJ (ORCPT + 1 other); Fri, 12 Jan 2018 07:24:09 -0500 Received: from mx2.suse.de ([195.135.220.15]:44702 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932705AbeALMYH (ORCPT ); Fri, 12 Jan 2018 07:24:07 -0500 Date: Fri, 12 Jan 2018 13:24:05 +0100 From: Michal Hocko To: Andrey Ryabinin Cc: Andrew Morton , Johannes Weiner , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Shakeel Butt Subject: Re: [PATCH v4] mm/memcg: try harder to decrease [memory,memsw].limit_in_bytes Message-ID: <20180112122405.GK1732@dhcp22.suse.cz> References: <20180109152622.31ca558acb0cc25a1b14f38c@linux-foundation.org> <20180110124317.28887-1-aryabinin@virtuozzo.com> <20180111104239.GZ1732@dhcp22.suse.cz> <4a8f667d-c2ae-e3df-00fd-edc01afe19e1@virtuozzo.com> <20180111124629.GA1732@dhcp22.suse.cz> <20180111162947.GG1732@dhcp22.suse.cz> <560a77b5-02d7-cbae-35f3-0b20a1c384c2@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <560a77b5-02d7-cbae-35f3-0b20a1c384c2@virtuozzo.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Fri 12-01-18 00:59:38, Andrey Ryabinin wrote: > On 01/11/2018 07:29 PM, Michal Hocko wrote: [...] > > I do not think so. Consider that this reclaim races with other > > reclaimers. Now you are reclaiming a large chunk so you might end up > > reclaiming more than necessary. SWAP_CLUSTER_MAX would reduce the over > > reclaim to be negligible. > > > > I did consider this. And I think, I already explained that sort of race in previous email. > Whether "Task B" is really a task in cgroup or it's actually a bunch of reclaimers, > doesn't matter. That doesn't change anything. I would _really_ prefer two patches here. The first one removing the hard coded reclaim count. That thing is just dubious at best. If you _really_ think that the higher reclaim target is meaningfull then make it a separate patch. I am not conviced but I will not nack it it either. But it will make our life much easier if my over reclaim concern is right and we will need to revert it. Conceptually those two changes are independent anywa. -- Michal Hocko SUSE Labs