From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754790AbdBGOxC (ORCPT ); Tue, 7 Feb 2017 09:53:02 -0500 Received: from mx2.suse.de ([195.135.220.15]:48864 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754258AbdBGOxA (ORCPT ); Tue, 7 Feb 2017 09:53:00 -0500 Date: Tue, 7 Feb 2017 15:52:57 +0100 From: Michal Hocko To: vinayak menon Cc: Vinayak Menon , Andrew Morton , Johannes Weiner , mgorman@techsingularity.net, vbabka@suse.cz, Rik van Riel , vdavydov.dev@gmail.com, anton.vorontsov@linaro.org, Minchan Kim , shashim@codeaurora.org, "linux-mm@kvack.org" , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2 v4] mm: vmscan: do not pass reclaimed slab to vmpressure Message-ID: <20170207145257.GT5065@dhcp22.suse.cz> References: <1486383850-30444-1-git-send-email-vinmenon@codeaurora.org> <20170206125240.GB10298@dhcp22.suse.cz> <20170207081002.GB5065@dhcp22.suse.cz> <20170207121744.GM5065@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 07-02-17 18:46:55, vinayak menon wrote: > On Tue, Feb 7, 2017 at 5:47 PM, Michal Hocko wrote: > > On Tue 07-02-17 16:39:15, vinayak menon wrote: [...] > >> Starting to kill at the right time helps in recovering memory at a > >> faster rate than waiting for the reclaim to complete. Yes, we may > >> be able to modify lowmemorykiller to cope with this problem. But > >> the actual problem this patch tried to fix was the vmpressure event > >> regression. > > > > I am not happy about the regression but you should try to understand > > that we might end up with another report a month later for a different > > consumer of events. > > I understand that. But this was the way vmpressure had worked until the > regression and IMHO adding reclaimed slab just increases the noise in > vmpressure. I would argue the previous behavior was wrong as well. > > I believe that the vmpressure needs some serious rethought and come with > > a more realistic and stable metric. > > Okay. I agree. So you are suggesting to drop the patch ? Unless there is a strong reason to keep it. Your test case seems to be rather artificial and the behavior is not much better after your patch. So rather than tunning the broken behavior for a particular test case I would welcome rethinking the whole thing. That being said I am not nacking the patch so if others think that this is a reasonable thing to do for now I will not stand in the way. -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f200.google.com (mail-wj0-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id B200B6B0033 for ; Tue, 7 Feb 2017 09:53:00 -0500 (EST) Received: by mail-wj0-f200.google.com with SMTP id kq3so26124938wjc.1 for ; Tue, 07 Feb 2017 06:53:00 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id 31si5279362wrj.324.2017.02.07.06.52.59 for (version=TLS1 cipher=AES128-SHA bits=128/128); Tue, 07 Feb 2017 06:52:59 -0800 (PST) Date: Tue, 7 Feb 2017 15:52:57 +0100 From: Michal Hocko Subject: Re: [PATCH 1/2 v4] mm: vmscan: do not pass reclaimed slab to vmpressure Message-ID: <20170207145257.GT5065@dhcp22.suse.cz> References: <1486383850-30444-1-git-send-email-vinmenon@codeaurora.org> <20170206125240.GB10298@dhcp22.suse.cz> <20170207081002.GB5065@dhcp22.suse.cz> <20170207121744.GM5065@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: vinayak menon Cc: Vinayak Menon , Andrew Morton , Johannes Weiner , mgorman@techsingularity.net, vbabka@suse.cz, Rik van Riel , vdavydov.dev@gmail.com, anton.vorontsov@linaro.org, Minchan Kim , shashim@codeaurora.org, "linux-mm@kvack.org" , linux-kernel@vger.kernel.org On Tue 07-02-17 18:46:55, vinayak menon wrote: > On Tue, Feb 7, 2017 at 5:47 PM, Michal Hocko wrote: > > On Tue 07-02-17 16:39:15, vinayak menon wrote: [...] > >> Starting to kill at the right time helps in recovering memory at a > >> faster rate than waiting for the reclaim to complete. Yes, we may > >> be able to modify lowmemorykiller to cope with this problem. But > >> the actual problem this patch tried to fix was the vmpressure event > >> regression. > > > > I am not happy about the regression but you should try to understand > > that we might end up with another report a month later for a different > > consumer of events. > > I understand that. But this was the way vmpressure had worked until the > regression and IMHO adding reclaimed slab just increases the noise in > vmpressure. I would argue the previous behavior was wrong as well. > > I believe that the vmpressure needs some serious rethought and come with > > a more realistic and stable metric. > > Okay. I agree. So you are suggesting to drop the patch ? Unless there is a strong reason to keep it. Your test case seems to be rather artificial and the behavior is not much better after your patch. So rather than tunning the broken behavior for a particular test case I would welcome rethinking the whole thing. That being said I am not nacking the patch so if others think that this is a reasonable thing to do for now I will not stand in the way. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org