From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx115.postini.com [74.125.245.115]) by kanga.kvack.org (Postfix) with SMTP id ED9E46B0071 for ; Wed, 5 Sep 2012 05:45:26 -0400 (EDT) Received: by pbbro12 with SMTP id ro12so716872pbb.14 for ; Wed, 05 Sep 2012 02:45:26 -0700 (PDT) Date: Wed, 5 Sep 2012 02:45:20 -0700 From: Tejun Heo Subject: Re: [RFC 0/5] forced comounts for cgroups. Message-ID: <20120905094520.GM3195@dhcp-172-17-108-109.mtv.corp.google.com> References: <20120905081439.GC3195@dhcp-172-17-108-109.mtv.corp.google.com> <50470A87.1040701@parallels.com> <20120905082947.GD3195@dhcp-172-17-108-109.mtv.corp.google.com> <50470EBF.9070109@parallels.com> <20120905084740.GE3195@dhcp-172-17-108-109.mtv.corp.google.com> <1346835993.2600.9.camel@twins> <20120905091140.GH3195@dhcp-172-17-108-109.mtv.corp.google.com> <50471782.6060800@parallels.com> <1346837209.2600.14.camel@twins> <50471C0C.7050600@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50471C0C.7050600@parallels.com> Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, davej@redhat.com, ben@decadent.org.uk, pjt@google.com, lennart@poettering.net, kay.sievers@vrfy.org Hello, On Wed, Sep 05, 2012 at 01:31:56PM +0400, Glauber Costa wrote: > > I simply don't want to have to do two (or more) hierarchy walks for > > accounting on every schedule event, all that pointer chasing is stupidly > > expensive. > > You wouldn't have to do more than one hierarchy walks for that. What > Tejun seems to want, is the ability to not have a particular controller > at some point in the tree. But if they exist, they are always together. Nope, as I wrote in the other reply, for cpu and cpuacct, either just merge them or kill cpuacct if you want to avoid silliness from walking multiple times. Does cpuset cause problem in this regard too? Or can it be handled similarly to other controllers? I think the confusion here is that we're talking about two different issues. As for cpuacct, I can see why strict co-mounting can be attractive but then again if that's gonna be required, there's no point in having them separate, right? If that's the way you want it, just trigger WARN_ON() if cpu and cpuacct aren't co-mounted and later on kill cpuacct. Thanks. -- tejun -- 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