Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932361AbVLPSpc (ORCPT ); Fri, 16 Dec 2005 13:45:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932364AbVLPSpc (ORCPT ); Fri, 16 Dec 2005 13:45:32 -0500 Received: from inti.inf.utfsm.cl ([200.1.21.155]:9897 "EHLO inti.inf.utfsm.cl") by vger.kernel.org with ESMTP id S932361AbVLPSpc (ORCPT ); Fri, 16 Dec 2005 13:45:32 -0500 Message-Id: <200512161842.jBGIgjZG003433@laptop11.inf.utfsm.cl> To: "linux-os \(Dick Johnson\)" cc: "Lee Revell" , "Jeff V. Merkey" , "Adrian Bunk" , "Andrew Morton" , linux-kernel@vger.kernel.org, arjan@infradead.org Subject: Re: [2.6 patch] i386: always use 4k stacks In-Reply-To: Message from "linux-os \(Dick Johnson\)" of "Fri, 16 Dec 2005 09:39:56 CDT." X-Mailer: MH-E 7.4.2; nmh 1.1; XEmacs 21.4 (patch 18) Date: Fri, 16 Dec 2005 15:42:45 -0300 From: Horst von Brand X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0b5 (inti.inf.utfsm.cl [200.1.19.1]); Fri, 16 Dec 2005 15:42:58 -0300 (CLST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1477 Lines: 30 linux-os \(Dick Johnson\) wrote: [...] > Throughout the past two years of 4k stack-wars, I never heard why > such a small stack was needed (not wanted, needed). It seems that > everybody "knows" that smaller is better and most everybody thinks > that one page in ix86 land is "optimum". However I don't think > anybody ever even tried to analyze what was better from a technical > perspective. Instead it's been analyzed as religious dogma, i.e., > keep the stack small, it will prevent idiots from doing bad things. OK, so here goes again... The kernel stack has to be contiguous in /physical/ memory. Keep the stack /one/ page, that way you can always get a new stack when needed (== each fork(2) or clone(2)). If the stack is 2 (or more) pages, you'll have to find (or create) a multi-page free area, and (fragmentation being what it is, and Linux routinely running for months at a time) you are in a whole new world of pain. -- Dr. Horst H. von Brand User #22616 counter.li.org Departamento de Informatica Fono: +56 32 654431 Universidad Tecnica Federico Santa Maria +56 32 654239 Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513 - 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/