From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750953AbWG1FTM (ORCPT ); Fri, 28 Jul 2006 01:19:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751773AbWG1FTM (ORCPT ); Fri, 28 Jul 2006 01:19:12 -0400 Received: from omx2-ext.sgi.com ([192.48.171.19]:4075 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S1750953AbWG1FTL (ORCPT ); Fri, 28 Jul 2006 01:19:11 -0400 Date: Thu, 27 Jul 2006 22:19:00 -0700 From: Paul Jackson To: linux-kernel@vger.kernel.org Cc: akpm@osdl.org, mm-commits@vger.kernel.org, npiggin@suse.de, mingo@elte.hu, sivanich@sgi.com Subject: Re: + sched-force-sbin-init-off-isolated-cpus.patch added to -mm tree Message-Id: <20060727221900.d87afdcc.pj@sgi.com> In-Reply-To: <200607280451.k6S4pEY9027994@shell0.pdx.osdl.net> References: <200607280451.k6S4pEY9027994@shell0.pdx.osdl.net> Organization: SGI X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.3; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nick wrote: > Force /sbin/init off isolated cpus (unless every CPU is specified as an > isolcpu). For our big honkin NUMA iron SGI customers, who are serious about this sort of thing, we actually already do this, entirely in user space. I use the init= kernel command line boot option to run a pre-init program, that sets up a configurable (by a config file in /etc) cpuset, then exec's the real init in that cpuset. This feature is known to SGI customers as the "bootcpuset." But Nick's patch looks ok to me. It seems harmless enough for our NUMA power users - as the bootcpuset they configured will just override what Nick's code did a few milliseconds (to read the pre-init executable off the disk) earlier, harmlessly. Meanwhile, the remaining (and likely vast majority of) isolcpu users will get the behaviour they prefer. Acked-by: Paul Jackson -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401