From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754034AbYLNJ4V (ORCPT ); Sun, 14 Dec 2008 04:56:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751857AbYLNJ4M (ORCPT ); Sun, 14 Dec 2008 04:56:12 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:49467 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751793AbYLNJ4L (ORCPT ); Sun, 14 Dec 2008 04:56:11 -0500 Date: Sun, 14 Dec 2008 01:55:56 -0800 From: Andrew Morton To: Yinghai Lu Cc: Ingo Molnar , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] add init_start_cpus to config boot cpus -v2 Message-Id: <20081214015556.16615d55.akpm@linux-foundation.org> In-Reply-To: <4944B5A4.9060706@kernel.org> References: <4944A279.5020009@kernel.org> <20081213221842.583f1e38.akpm@linux-foundation.org> <4944B5A4.9060706@kernel.org> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 13 Dec 2008 23:28:36 -0800 Yinghai Lu wrote: > > Impact: new command line > > so could select cpus to be started during init stage. I already knew that :( > example: > init_start_cpus=2,4,6 > to start core 0 only on every node or thread 0 or all cores > > init_start_cpus=0 > not start other APs, and later let user to use > echo 1 > /sys/devices/cpu/cpu2 > to start them in user space. > But why? Why is this useful? Why did you even bother writing the code? Who wants this? For what reason? What value has it? This stuff matters. > +static __initdata cpumask_var_t cpu_init_start_mask; OK. I also suggested that this code not be added in init/main.c. What happened to that idea?