From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030272AbWJSIW6 (ORCPT ); Thu, 19 Oct 2006 04:22:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030315AbWJSIW5 (ORCPT ); Thu, 19 Oct 2006 04:22:57 -0400 Received: from smtp102.mail.mud.yahoo.com ([209.191.85.212]:18518 "HELO smtp102.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1030272AbWJSIW4 (ORCPT ); Thu, 19 Oct 2006 04:22:56 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=y16vV6QEQx30irn5BoNZu4Bpa4Ym4vOOYPkITt6oh23Nw54boKFsMg+F7CKQYpDpJtk2DcksyD95oYPORNPWtfpTVEQ4/2QgCbc3lLmqQSIVJ3NoM92btPm+MAUlawXfFxTfammcMuumoRkbAYk0bqP691cmQi1yNLPRwZ0d0f4= ; Message-ID: <453735D8.5040100@yahoo.com.au> Date: Thu, 19 Oct 2006 18:22:48 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Paul Jackson CC: holt@sgi.com, suresh.b.siddha@intel.com, dino@in.ibm.com, menage@google.com, Simon.Derr@bull.net, linux-kernel@vger.kernel.org, mbligh@google.com, rohitseth@google.com, dipankar@in.ibm.com Subject: Re: exclusive cpusets broken with cpu hotplug References: <20061017192547.B19901@unix-os.sc.intel.com> <20061018001424.0c22a64b.pj@sgi.com> <20061018095621.GB15877@lnx-holt.americas.sgi.com> <20061018031021.9920552e.pj@sgi.com> <45361B32.8040604@yahoo.com.au> <20061018231559.8d3ede8f.pj@sgi.com> <45371CBB.2030409@yahoo.com.au> <20061018235746.95343e77.pj@sgi.com> <4537238A.7060106@yahoo.com.au> <20061019003405.15a4dd8c.pj@sgi.com> <45373241.5060203@yahoo.com.au> <20061019011152.752f9657.pj@sgi.com> In-Reply-To: <20061019011152.752f9657.pj@sgi.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Paul Jackson wrote: >>Paul Jackson wrote: >> >>>Nick wrote: >>> >>> >>>>(we simply shouldn't allow >>>>situations where we put a partition in the middle of a cpuset). >>> >>> >>>Could you explain to me what you mean by "put a partition in the >>>middle of a cpuset?" >>> >> >>Your example, if a partition is created for each of the sub cpusets. > > > The thing "we simply shouldn't allow", then, is the bread and > butter of cpusets. No. They can put a cpuset there all they like. But the cpuset code should *not* put a partition there. That is all. > > I am convinced that we are trying to pound nails with toothpicks. > > The cpu_exclusive flag was the wrong flag to overload to define > sched domains. Well it is the correct flag if we only create the domain for the oldest ancestor with the cpu_exclusive flag set. From the documentation: "A cpuset may be marked exclusive, which ensures that no other cpuset (except direct ancestors and descendents) may contain any overlapping CPUs or Memory Nodes." It is this non overlapping property that we can take advantage of, and partition the scheduler. Obviously, the exception (from the POV of the oldest ancestor) is its descendents, which can be overlapping. So just don't create partitions for those guys. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com