From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f180.google.com (mail-we0-f180.google.com [74.125.82.180]) by kanga.kvack.org (Postfix) with ESMTP id F16606B0037 for ; Mon, 16 Jun 2014 10:04:52 -0400 (EDT) Received: by mail-we0-f180.google.com with SMTP id x48so5712412wes.39 for ; Mon, 16 Jun 2014 07:04:52 -0700 (PDT) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id n20si8647213wiw.90.2014.06.16.07.04.50 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 16 Jun 2014 07:04:51 -0700 (PDT) Date: Mon, 16 Jun 2014 16:04:48 +0200 From: Michal Hocko Subject: Re: [PATCH 2/2] memcg: Allow guarantee reclaim Message-ID: <20140616140448.GE16915@dhcp22.suse.cz> References: <20140611075729.GA4520@dhcp22.suse.cz> <1402473624-13827-1-git-send-email-mhocko@suse.cz> <1402473624-13827-2-git-send-email-mhocko@suse.cz> <20140611153631.GH2878@cmpxchg.org> <20140612132207.GA32720@dhcp22.suse.cz> <20140612135600.GI2878@cmpxchg.org> <20140612142237.GB32720@dhcp22.suse.cz> <20140612161733.GC23606@htj.dyndns.org> <20140616125915.GB16915@dhcp22.suse.cz> <20140616135741.GA11542@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140616135741.GA11542@htj.dyndns.org> Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Johannes Weiner , Greg Thelen , Hugh Dickins , Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Michel Lespinasse , Roman Gushchin , linux-mm@kvack.org, LKML , Li Zefan On Mon 16-06-14 09:57:41, Tejun Heo wrote: > Hello, Michal. > > On Mon, Jun 16, 2014 at 02:59:15PM +0200, Michal Hocko wrote: > > > There sure is a question of how fast userland will move to the new > > > interface. > > > > Yeah, I was mostly thinking about those who would need to to bigger > > changes. AFAIR threads will no longer be distributable between groups. > > Thread-level granularity should go away no matter what, but this is > completely irrelevant to memcg which can't do per-thread anyway. Yes, I wasn't afraid about memcg. It was a setup which requires more controllers that I was worried about. > For whatever reason, a user is stuck with thread-level granularity for > controllers which work that way, the user can use the old hierarchies > for them for the time being. So he can mount memcg with new cgroup API and others with old? > > > is used but I don't think there's any chance of removing the knob. > > > There's a reason why we're introducing a new version of the whole > > > cgroup interface which can co-exist with the existing one after all. > > > If you wanna version memcg interface separately, maybe that'd work but > > > it sounds like a lot of extra hassle for not much gain. > > > > No, I didn't mean to version the interface. I just wanted to have > > gradual transition for potential soft_limit users. > > > > Maybe I am misunderstanding something but I thought that new version of > > API will contain all knobs which are not marked .flags = CFTYPE_INSANE > > while the old API will contain all of them. > > Nope, some changes don't fit that model. CFTYPE_ON_ON_DFL is the > opposite. OK, I wasn't aware of this. On which branch I find this? > Knobs marked with the flag only appear on the default > hierarchy (cgroup core internally calls it the default hierarchy as > this is the tree all the controllers are attached to by default). I am not sure I understand. So they are visible only in the hierarchy mounted with the new cgroup API (sane or how is it called)? -- 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