From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261202AbVDTHbE (ORCPT ); Wed, 20 Apr 2005 03:31:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261253AbVDTHbD (ORCPT ); Wed, 20 Apr 2005 03:31:03 -0400 Received: from e31.co.us.ibm.com ([32.97.110.129]:42973 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S261202AbVDTHa4 (ORCPT ); Wed, 20 Apr 2005 03:30:56 -0400 Date: Wed, 20 Apr 2005 13:07:44 +0530 From: Dinakar Guniguntala To: Paul Jackson Cc: nickpiggin@yahoo.com.au, Simon.Derr@bull.net, linux-kernel@vger.kernel.org, lse-tech@lists.sourceforge.net, akpm@osdl.org, dipankar@in.ibm.com, colpatch@us.ibm.com Subject: Re: [RFC PATCH] Dynamic sched domains aka Isolated cpusets Message-ID: <20050420073744.GB3931@in.ibm.com> Reply-To: dino@in.ibm.com References: <1097110266.4907.187.camel@arrakis> <20050418202644.GA5772@in.ibm.com> <20050418225427.429accd5.pj@sgi.com> <1113891575.5074.46.camel@npiggin-nld.site> <20050419095230.GC3963@in.ibm.com> <20050419082639.62d706ca.pj@sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050419082639.62d706ca.pj@sgi.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 19, 2005 at 08:26:39AM -0700, Paul Jackson wrote: > * Your understanding of "cpu_exclusive" is not the same as mine. Sorry for creating confusion by what I said earlier, I do understand exactly what cpu_exclusive means. Its just that when I started working on this (a long time ago) I had a different notion and that is what I was referring to, I probably should never have brought that up > > > Since isolated cpusets are trying to partition the system, this > > can be restricted to only the first level of cpusets. > > I do not think such a restriction is a good idea. For example, lets say > our 8 CPU system has the following cpusets: > And my current implementation has no such restriction, I was only suggesting that to simplify the code. > > > Also I think we can add further restrictions in terms not being able > > to change (add/remove) cpus within a isolated cpuset. > > My approach agrees on this restriction. Earlier I wrote: > > Also note that adding or removing a cpu from a cpuset that has > > its domain_cpu_current flag set true must fail, and similarly > > for domain_mem_current. > > This restriction is required in my approach because the CPUs in the > domain_cpu_current cpusets (the isolated CPUs, in your terms) form a > partition (disjoint cover) of the CPUs in the system, which property > would be violated immediately if any CPU were added or removed from any > cpuset defining the partition. See my other note explaining how things work currently. I do feel that this restriction is not good -Dinakar