Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932376AbVLPTCO (ORCPT ); Fri, 16 Dec 2005 14:02:14 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932381AbVLPTCO (ORCPT ); Fri, 16 Dec 2005 14:02:14 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:59607 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932377AbVLPTCN (ORCPT ); Fri, 16 Dec 2005 14:02:13 -0500 Subject: Re: [2.6 patch] i386: always use 4k stacks From: Arjan van de Ven To: Brian Gerst Cc: linux-kernel@vger.kernel.org In-Reply-To: <43A30D36.5090406@didntduck.org> References: <200512161842.jBGIgjZG003433@laptop11.inf.utfsm.cl> <43A30D36.5090406@didntduck.org> Content-Type: text/plain Date: Fri, 16 Dec 2005 20:02:10 +0100 Message-Id: <1134759731.2992.57.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit X-Spam-Score: -2.8 (--) X-Spam-Report: SpamAssassin version 3.0.4 on pentafluge.infradead.org summary: Content analysis details: (-2.8 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.8 ALL_TRUSTED Did not pass through any untrusted hosts X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 875 Lines: 21 > > So what about arches where single-page stacks aren't viable (for example > x86_64)? Are we just screwed? x86 is specially handicapped due to the fact that the stacks need to be in the lowmem zone. Even if you have 8Gb ram, the lowmem zone is still 800Mb and a bit, and this gets to be under a high pressure, like hyper-fragmentation. Same for bounce buffers etc etc. note that the order thing is by far not the only advantage, pure memory usage alone and cache locality also are wins. The memory usage halves for kernel stacks after all (which means you can do more threads in java, or use the memory for disk cache ;) - 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/