Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754257AbXEHGDO (ORCPT ); Tue, 8 May 2007 02:03:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754114AbXEHGDJ (ORCPT ); Tue, 8 May 2007 02:03:09 -0400 Received: from holomorphy.com ([66.93.40.71]:59473 "EHLO holomorphy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752808AbXEHGDI (ORCPT ); Tue, 8 May 2007 02:03:08 -0400 Date: Mon, 7 May 2007 23:03:42 -0700 From: William Lee Irwin III To: Andrew Morton Cc: Jeremy Fitzhardinge , Simon Arlott , linux-kernel@vger.kernel.org, Andi Kleen Subject: Re: sleeping function called from invalid context at block/cfq-iosched.c (Was: Re: 2.6.21-mm1) Message-ID: <20070508060342.GH19966@holomorphy.com> References: <463E3C50.9080207@simon.arlott.org.uk> <20070506135403.a6785f7d.akpm@linux-foundation.org> <463FAF1C.8060500@simon.arlott.org.uk> <20070507162349.0790706f.akpm@linux-foundation.org> <463FB697.6060902@simon.arlott.org.uk> <20070507163335.f5f5ea6e.akpm@linux-foundation.org> <463FFD0A.2050708@goop.org> <20070507222409.2d597a86.akpm@linux-foundation.org> <20070508053132.GZ31925@holomorphy.com> <20070507223738.57d763da.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070507223738.57d763da.akpm@linux-foundation.org> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2026 Lines: 40 On Mon, 7 May 2007 22:31:32 -0700 William Lee Irwin III wrote: >> I think Andi's handling the mergework on those patches, but I'll check >> in to see if I should rediff vs. -mm or what if you want them. >> Andi, what's the verdict on those stack patches? On Mon, May 07, 2007 at 10:37:38PM -0700, Andrew Morton wrote: > Whoa. The verdict is usually "don't use so much stack". > Do we know what has gone wrong here? > Last week Jens said he was picking up the ancient > md-dm-reduce-stack-usage-with-stacked-block-devices.patch, but he doesn't > seem to have done so yet. > XFS is frequently implicated. Well, the culmination of those patches is a patch to use vmallocspace to establish guard pages for stacks so overflows are immediately trapped and the potential for silent corruption greatly reduced. That would be where I suspect it's most relevant, as that's the focal point of the series. The bit about unconditional IRQ stacks arose as part of review. It started life as a set of patches intended to help with debugging stack overflows, which is how the only tangentially-related unconditional IRQ stacks came about: originally they were optional as a debug option for differential diagnosis of interrupt-time overflows. For mainline, hch suggested that they should rather be made unconditional. The third part of the series that survived review was dynamic boot-time allocation of IRQ stacks, which was originally motivated by the need for indirection when remapping IRQ stacks into vmallocspace, but also served the purpose of mitigating space overhead when using IRQ stacks because cpu_possible_map is not set up as it should be to avoid the allocation via per_cpu array variables' dynamic boot-time allocation on i386 and (AFAIK) x86-64. -- wli - 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/