Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964830AbWHCS0h (ORCPT ); Thu, 3 Aug 2006 14:26:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964833AbWHCS0h (ORCPT ); Thu, 3 Aug 2006 14:26:37 -0400 Received: from iona.labri.fr ([147.210.8.143]:24036 "EHLO iona.labri.fr") by vger.kernel.org with ESMTP id S964830AbWHCS0g (ORCPT ); Thu, 3 Aug 2006 14:26:36 -0400 Date: Thu, 3 Aug 2006 20:26:34 +0200 From: Samuel Thibault To: Steven Rostedt Cc: Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix initialization of runqueues Message-ID: <20060803182634.GD4368@implementation.labri.fr> Mail-Followup-To: Samuel Thibault , Steven Rostedt , Ingo Molnar , linux-kernel@vger.kernel.org References: <20060802122743.GF4460@implementation.labri.fr> <20060802152419.GA31970@elte.hu> <20060802165742.GI4460@implementation.labri.fr> <1154617657.32264.14.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1154617657.32264.14.camel@localhost.localdomain> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1427 Lines: 34 Steven Rostedt, le Thu 03 Aug 2006 11:07:37 -0400, a ?crit : > On Wed, 2006-08-02 at 18:57 +0200, Samuel Thibault wrote: > > Ingo Molnar, le Wed 02 Aug 2006 17:24:19 +0200, a ?crit : > > > > > > * Samuel Thibault wrote: > > > > > > > Hi, > > > > > > > > There's an odd thing about the nr_active field in arrays of > > > > runqueue_t: it is actually never initialized to 0!... This doesn't > > > > yet trigger a bug probably because the way runqueues are allocated > > > > make it so that it is already initialized to 0, but that's not a safe > > > > way. Here is a patch: > > > > > > we do rely on zero initialization of bss (and percpu) data in a number > > > of places. > > > > The rest of runqueue initialization doesn't rely on that, and as > > a result people might think that it is safe to allocate runqueues > > dynamically. > > I don't buy the "safe to allocate runqueues dynamically" bit since they > are local to sched.c and if you do do that (I did for a customer once) > you better know what you're doing. Yes, but as you agreed, initializing some members to 0 and not others doesn't help to know what you're doing :) Samuel - 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/