From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx180.postini.com [74.125.245.180]) by kanga.kvack.org (Postfix) with SMTP id 33CEF6B0032 for ; Tue, 25 Jun 2013 12:08:00 -0400 (EDT) Date: Tue, 25 Jun 2013 18:07:56 +0200 From: Michal Hocko Subject: Re: [PATCH v6] memcg: event control at vmpressure. Message-ID: <20130625160756.GB10617@dhcp22.suse.cz> References: <20130618110151.GI13677@dhcp22.suse.cz> <00fd01ce6ce0$82eac0a0$88c041e0$%kim@samsung.com> <20130619125329.GB16457@dhcp22.suse.cz> <000401ce6d5c$566ac620$03405260$%kim@samsung.com> <20130620121649.GB27196@dhcp22.suse.cz> <001e01ce6e15$3d183bd0$b748b370$%kim@samsung.com> <001f01ce6e15$b7109950$2531cbf0$%kim@samsung.com> <20130621012234.GF11659@bbox> <20130621091944.GC12424@dhcp22.suse.cz> <20130621162743.GA2837@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130621162743.GA2837@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Hyunhee Kim , 'Anton Vorontsov' , linux-mm@kvack.org, akpm@linux-foundation.org, rob@landley.net, kamezawa.hiroyu@jp.fujitsu.com, hannes@cmpxchg.org, rientjes@google.com, kirill@shutemov.name, 'Kyungmin Park' Hi, On Sat 22-06-13 01:27:43, Minchan Kim wrote: > > > Question. > > > > > > 1. user: set critical edge > > > 2. kernel: memory is tight and trigger event with critical > > > 3. user: kill a program when he receives a event > > > 4. kernel: memory is very tight again and want to trigger a event > > > with critical but fail because last_level was critical and it was edge. > > > > > > Right? > > > > yes, this is the risk of the edge triggering and the user has to be > > prepared for that. I still think that it makes some sense to have the > > two modes. > > I'm not sure it's good idea. > How could user overcome above problem? Well, if the interface is proposed to workaround issues of the current implementation then it is surely not a good path. I was referring to a concept of edge triggering which makes some sense to me. Consider one shot actions that should start/stop a certain action when the level changes (e.g. very popular notification to admin). [...] -- 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