Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932365AbVLPSxP (ORCPT ); Fri, 16 Dec 2005 13:53:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932368AbVLPSxP (ORCPT ); Fri, 16 Dec 2005 13:53:15 -0500 Received: from quark.didntduck.org ([69.55.226.66]:46464 "EHLO quark.didntduck.org") by vger.kernel.org with ESMTP id S932365AbVLPSxL (ORCPT ); Fri, 16 Dec 2005 13:53:11 -0500 Message-ID: <43A30D36.5090406@didntduck.org> Date: Fri, 16 Dec 2005 13:53:42 -0500 From: Brian Gerst User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Horst von Brand CC: "linux-os (Dick Johnson)" , 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 References: <200512161842.jBGIgjZG003433@laptop11.inf.utfsm.cl> In-Reply-To: <200512161842.jBGIgjZG003433@laptop11.inf.utfsm.cl> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1382 Lines: 34 Horst von Brand wrote: > 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. So what about arches where single-page stacks aren't viable (for example x86_64)? Are we just screwed? -- Brian Gerst - 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/