Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754350AbYH0BuD (ORCPT ); Tue, 26 Aug 2008 21:50:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752964AbYH0Bty (ORCPT ); Tue, 26 Aug 2008 21:49:54 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38582 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751339AbYH0Btx (ORCPT ); Tue, 26 Aug 2008 21:49:53 -0400 Date: Tue, 26 Aug 2008 18:49:19 -0700 (PDT) From: Linus Torvalds To: Parag Warudkar cc: Adrian Bunk , Rusty Russell , "Alan D. Brunelle" , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Andrew Morton , Arjan van de Ven , Ingo Molnar , linux-embedded@vger.kernel.org Subject: Re: [Bug #11342] Linux 2.6.27-rc3: kernel BUG at mm/vmalloc.c - bisected In-Reply-To: Message-ID: References: <200808261111.19205.rusty@rustcorp.com.au> <20080826183051.GB10925@cs181140183.pp.htv.fi> <20080826205916.GB11734@cs181140183.pp.htv.fi> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1535 Lines: 37 On Tue, 26 Aug 2008, Parag Warudkar wrote: > > And although you said in your later reply that Linux x86 with 4K > stacks should be more than usable - my experiences running a untainted > desktop/file server with 4K stack have been always disastrous XFS or > not. It _might_ work for some well defined workloads but you would > not want to risk 4K stacks otherwise. Umm. How long? 4kB used to be the _only_ choice. And no, there weren't even irq stacks. So that 4kB was not just the whole kernel call-chain, it was also all the irq nesting above it. And yes, we've gotten much worse over time, and no, I can't really suggest going back to that in general. The code bloat has certainly been accompanied by a stack bloat too. But part of it is definitely gcc. Some versions of gcc used to be absolutely _horrid_ when it came to stack usage, especially with some flags, and especially with the crazy inlining that module-at-a-time caused. But I'd be really happy if some embedded people tried to take some of that bloat back, and aim for 4kB stacks. Because it's definitely not unrealistic. At least it _shouldn't_ be. And a lot of the cases of us having structures on the stack is actually not worth it, and tends to be about being lazy rather than anything else. Linus -- 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/