From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752060AbdJZVAA (ORCPT ); Thu, 26 Oct 2017 17:00:00 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:44268 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752016AbdJZU74 (ORCPT ); Thu, 26 Oct 2017 16:59:56 -0400 X-Google-Smtp-Source: ABhQp+QTmvjfNEyGrBy2POKaQRmYA9n41IDqVpv43br7jHmeoBQGZKAbOY0Xzinj3bzh0qmNpAk//w== Date: Thu, 26 Oct 2017 22:59:16 +0200 From: Christian Brauner To: Waiman Long Cc: Tejun Heo , Li Zefan , Johannes Weiner , Jonathan Corbet , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, Mike Galbraith , =?utf-8?B?U3TDqXBoYW5l?= Graber , Serge Hallyn Subject: Re: [PATCH v3] cpuset: Enable cpuset controller in default hierarchy Message-ID: <20171026205915.ztcc3yg7wzemlbzw@gmail.com> References: <1507324230-22996-1-git-send-email-longman@redhat.com> <20171026143908.GD59538@devbig577.frc2.facebook.com> <2814be69-8dc1-b2f8-406e-cc4dda289d94@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <2814be69-8dc1-b2f8-406e-cc4dda289d94@redhat.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 26, 2017 at 02:12:01PM -0400, Waiman Long wrote: > On 10/26/2017 10:39 AM, Tejun Heo wrote: > > Hello, Waiman. > > > > On Wed, Oct 25, 2017 at 11:50:34AM -0400, Waiman Long wrote: > >> Ping! Any comment on this patch? Fwiw, I just saw this patch today for some weird reason. > > Sorry about the lack of response. Here are my two thoughts. > > > > 1. I'm not really sure about the memory part. Mostly because of the > > way it's configured and enforced is completely out of step with how > > mm behaves in general. I'd like to get more input from mm folks on > > this. > > Yes, I also have doubt about which of the additional features are being > actively used. That is why the current patch exposes only the memory_migrate > flag in addition to the core *cpus and *mems control files. All the > other v1 features are not exposed waiting for further investigation and > feedback. One way to get more feedback is to have something that people > can play with. Maybe we could somehow tag it as experimental so that we > can change the interface later on, when necessary, if you have concern > about setting the APIs in stone. This sounds like a reasonable approach to me. The cpuset controller is quite important from a userspace (especially container) perspective. So making this an experimental feature for a while to gather feedback seems worth it. I'd be happy to carry/receive some experimental patches in a liblxc branch for cgroup v2 to see where the current cpuset controller implementation currently gets us and send/discuss patches where needed. > > > 2. I want to think more about how we expose the effective settings. > > Not that anything is wrong with what cpuset does, but more that I > > wanna ensure that it's something we can follow in other cases where > > we have similar hierarchical property propagation. > > Currently, the effective setting is exposed via the effective_cpus and > effective_mems control files. Unlike other controllers that control > resources, cpuset is unique in the sense that it is propagating > hierarchical constraints on CPUs and memory nodes down the tree. I > understand your desire to have a unified framework that can be applied > to most controllers, but I doubt cpuset is a good model in this regard. > > Cheers, > Longman >