From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx113.postini.com [74.125.245.113]) by kanga.kvack.org (Postfix) with SMTP id 58D956B0032 for ; Fri, 17 May 2013 13:39:01 -0400 (EDT) In-Reply-To: <20130517165712.GB12632@mtj.dyndns.org> References: <1368431172-6844-1-git-send-email-mhocko@suse.cz> <1368431172-6844-2-git-send-email-mhocko@suse.cz> <20130517160247.GA10023@cmpxchg.org> <20130517165712.GB12632@mtj.dyndns.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Subject: Re: [patch v3 -mm 1/3] memcg: integrate soft reclaim tighter with zone shrinking code From: Johannes Weiner Date: Fri, 17 May 2013 13:27:09 -0400 Message-ID: Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Michal Hocko , Andrew Morton , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, KAMEZAWA Hiroyuki , Ying Han , Hugh Dickins , Glauber Costa , Michel Lespinasse , Greg Thelen , Balbir Singh Tejun Heo wrote: >Hello, Johannes. > >On Fri, May 17, 20= 13 at 12:02:47PM -0400, Johannes Weiner wrote: >> There are setups with tho= usands of groups that do not even use soft >> limits. Having them pointles= sly iterate over all of them for every >> couple of pages reclaimed is just= not acceptable. > >Hmmm... if the iteration is the problem, it shouldn't b= e difficult to >build list of children which should be iterated. Would tha= t make it >acceptable? You mean, a separate structure that tracks which gr= oups are in excess of the limit? Like the current tree? :) Kidding aside,= yes, that would be better, and an unsorted list would probably be enough f= or the global case. To support target reclaim soft limits later on, we cou= ld maybe propagate tags upwards the cgroup tree when a group is in excess s= o that reclaim can be smarter about which subtrees to test for soft limits = and which to skip during the soft limit pass. The no-softlimit-set-anywher= e case is then only a single tag test in the root cgroup. But starting wit= h the list would be simple enough, delete a bunch of code, come with the sa= me performance improvements etc. -- Sent from my Android phone with K-9 Ma= il. Please excuse my brevity. -- 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