Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752530AbYKRKiR (ORCPT ); Tue, 18 Nov 2008 05:38:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751099AbYKRKiA (ORCPT ); Tue, 18 Nov 2008 05:38:00 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:46882 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809AbYKRKh7 (ORCPT ); Tue, 18 Nov 2008 05:37:59 -0500 Date: Tue, 18 Nov 2008 11:37:26 +0100 From: Ingo Molnar To: Christoph Hellwig Cc: Benjamin Herrenschmidt , Steven Rostedt , LKML , Paul Mackerras , linuxppc-dev@ozlabs.org, Linus Torvalds , Andrew Morton , Thomas Gleixner , Arjan van de Ven Subject: Re: Large stack usage in fs code (especially for PPC64) Message-ID: <20081118103726.GB31146@elte.hu> References: <1226963005.7178.248.camel@pasglop> <20081118095305.GA24119@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081118095305.GA24119@infradead.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1486 Lines: 33 * Christoph Hellwig wrote: > On Tue, Nov 18, 2008 at 10:03:25AM +1100, Benjamin Herrenschmidt wrote: > > On Mon, 2008-11-17 at 15:34 -0500, Steven Rostedt wrote: > > > Note, I was using a default config that had CONFIG_IRQSTACKS off and > > > CONFIG_PPC_64K_PAGES on. > > > > For one, we definitely need to turn IRQSTACKS on by default ... In fact, > > I'm pondering just removing the option. > > It shouldn't be a user-visible option. It shouldn't on x86 either, > but there it always gets into the ideological 4k stacks flameware so > people usually gave up after a while instead of doing the sensibke > 8k + irqstacks by default, 4k as an option.. yep, i tend to agree that 8k + irqstacks on both 32-bit and 64-bit would be the sane default. There's just too much gcc and other noise for us to have that cushion by default on 32-bit too. 64-bit is already there, on 32-bit we should decouple irqstacks from 4K stacks and just turn irqstacks on by default. Life's too short to fight kernel stack overflows - and now we've got the stack-tracer that will record and show the frame of the worst-ever kernel stack situation the system was in since bootup. (see Steve's tracer output in this thread) Ingo -- 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/