From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx190.postini.com [74.125.245.190]) by kanga.kvack.org (Postfix) with SMTP id 6279B6B00A3 for ; Wed, 5 Sep 2012 05:26:58 -0400 (EDT) Message-ID: <1346837209.2600.14.camel@twins> Subject: Re: [RFC 0/5] forced comounts for cgroups. From: Peter Zijlstra Date: Wed, 05 Sep 2012 11:26:49 +0200 In-Reply-To: <50471782.6060800@parallels.com> References: <1346768300-10282-1-git-send-email-glommer@parallels.com> <20120904214602.GA9092@dhcp-172-17-108-109.mtv.corp.google.com> <5047074D.1030104@parallels.com> <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> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: Tejun Heo , 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 On Wed, 2012-09-05 at 13:12 +0400, Glauber Costa wrote: > On 09/05/2012 01:11 PM, Tejun Heo wrote: > > Hello, Peter. > >=20 > > On Wed, Sep 05, 2012 at 11:06:33AM +0200, Peter Zijlstra wrote: > >> *confused* I always thought that was exactly what you meant with unifi= ed > >> hierarchy. > >=20 > > No, I never counted out differing granularity. > >=20 >=20 > Can you elaborate on which interface do you envision to make it work? > They will clearly be mounted in the same hierarchy, or as said > alternatively, comounted. >=20 > If you can turn them on/off on a per-subtree basis, which interface > exactly do you propose for that? I wouldn't, screw that. That would result in the exact same problem we're trying to fix. I want a single hierarchy walk, that's expensive enough. > Would a pair of cgroup core files like available_controllers and > current_controllers are a lot of drivers do, suffice? No.. its not a 'feature' I care to support for 'my' controllers. 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. -- 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