Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753346AbaFPN5q (ORCPT ); Mon, 16 Jun 2014 09:57:46 -0400 Received: from mail-qc0-f173.google.com ([209.85.216.173]:47807 "EHLO mail-qc0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775AbaFPN5o (ORCPT ); Mon, 16 Jun 2014 09:57:44 -0400 Date: Mon, 16 Jun 2014 09:57:41 -0400 From: Tejun Heo To: Michal Hocko Cc: Johannes Weiner , Greg Thelen , Hugh Dickins , Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Michel Lespinasse , Roman Gushchin , linux-mm@kvack.org, LKML , Li Zefan Subject: Re: [PATCH 2/2] memcg: Allow guarantee reclaim Message-ID: <20140616135741.GA11542@htj.dyndns.org> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140616125915.GB16915@dhcp22.suse.cz> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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. > > 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. 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). Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/