From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751099AbcB2UzO (ORCPT ); Mon, 29 Feb 2016 15:55:14 -0500 Received: from mail-qk0-f178.google.com ([209.85.220.178]:36426 "EHLO mail-qk0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750905AbcB2UzM (ORCPT ); Mon, 29 Feb 2016 15:55:12 -0500 Date: Mon, 29 Feb 2016 15:55:09 -0500 From: Tejun Heo To: Johannes Weiner Cc: Vladimir Davydov , Andrew Morton , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org Subject: Re: [PATCH] mm: memcontrol: reset memory.low on css offline Message-ID: <20160229205509.GW3965@htj.duckdns.org> References: <1456766193-16255-1-git-send-email-vdavydov@virtuozzo.com> <20160229200255.GA32539@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160229200255.GA32539@cmpxchg.org> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Mon, Feb 29, 2016 at 03:02:55PM -0500, Johannes Weiner wrote: > > To fix this, let's reset memory.low on css offline. > > We already have mem_cgroup_css_reset() for soft-offlining a css - when > the css is asked to be disabled but another subsystem still uses it. > Can we just call that function during offline as well? The css can be > around for quite a bit after the user deleted it. Eliminating *any* > user-supplied configurations and zapping it back to defaults makes > sense in general, so that we never have to worry about any remnants. Hmmm... I wonder whether the behavior can be a bit surprising and it could be better to simply let memcg offline callback to call the reset function explicitly. No big deal either way tho. Please feel free to send a patch. Thanks. -- tejun