Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755837AbXJCD6q (ORCPT ); Tue, 2 Oct 2007 23:58:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751522AbXJCD6j (ORCPT ); Tue, 2 Oct 2007 23:58:39 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:58681 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751408AbXJCD6i (ORCPT ); Tue, 2 Oct 2007 23:58:38 -0400 Date: Wed, 3 Oct 2007 09:39:39 +0530 From: Srivatsa Vaddagiri To: Eric St-Laurent Cc: Ingo Molnar , Dhaval Giani , Mike Galbraith , Peter Zijlstra , Dmitry Adamushko , lkml , maneesh@linux.vnet.ibm.com, Andrew Morton , Sudhir Kumar Subject: Re: [RFC/PATCH] Add sysfs control to modify a user's cpu share Message-ID: <20071003040939.GI5724@linux.vnet.ibm.com> Reply-To: vatsa@linux.vnet.ibm.com References: <20070925131717.GM26289@linux.vnet.ibm.com> <1190725693.13716.10.camel@Homer.simpson.net> <20070925132528.GN26289@linux.vnet.ibm.com> <1190726682.11260.1.camel@Homer.simpson.net> <20070925140559.GB26310@linux.vnet.ibm.com> <20070925143755.GA15594@elte.hu> <20070926210737.GA8663@elte.hu> <20071001140454.GA19439@linux.vnet.ibm.com> <20071001144402.GA3505@elte.hu> <1191363159.29539.15.camel@perkele> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1191363159.29539.15.camel@perkele> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1548 Lines: 35 On Tue, Oct 02, 2007 at 06:12:39PM -0400, Eric St-Laurent wrote: > While a sysfs interface is OK and somewhat orthogonal to the interface > proposed the containers patches, I think maybe a new syscall should be > considered. We had discussed syscall vs filesystem based interface for resource management [1] and there was a heavy bias favoring filesystem based interface, based on which the container (now "cgroup") filesystem evolved. Where we already have one interface defined, I would be against adding an equivalent syscall interface. Note that this "fair-user" scheduling can in theory be accomplished using the same cgroup based interface, but requires some extra setup in userspace (either to run a daemon which moves tasks to appropriate control groups/containers upon their uid change OR to modify initrd to mount cgroup filesystem at early bootup time). I expect most distros to enable CONFIG_FAIR_CGROUP_SCHED (control group based fair group scheduler) and not CONFIG_FAIR_USER_SHCED (user id based fair group scheduler). The only reason why we are providing CONFIG_FAIR_USER_SCHED and the associated sysfs interface is to help test group scheduler w/o requiring knowledge of cgroup filesystem. Reference: 1. http://marc.info/?l=linux-kernel&m=116231242201300&w=2 -- Regards, vatsa - 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/