From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932395AbVHaOmY (ORCPT ); Wed, 31 Aug 2005 10:42:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932496AbVHaOmY (ORCPT ); Wed, 31 Aug 2005 10:42:24 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:8389 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S932395AbVHaOmX (ORCPT ); Wed, 31 Aug 2005 10:42:23 -0400 Subject: Re: [PATCH 1/1] Implement shared page tables From: Arjan van de Ven To: "Martin J. Bligh" Cc: Hugh Dickins , Dave McCracken , Andrew Morton , Linux Kernel , Linux Memory Management In-Reply-To: <16640000.1125498711@[10.10.2.4]> References: <7C49DFF721CB4E671DB260F9@[10.1.1.4]> <1125489077.3213.12.camel@laptopd505.fenrus.org> <16640000.1125498711@[10.10.2.4]> Content-Type: text/plain Date: Wed, 31 Aug 2005 16:41:57 +0200 Message-Id: <1125499318.3213.18.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.2.2 (2.2.2-5) Content-Transfer-Encoding: 7bit X-Spam-Score: 2.9 (++) X-Spam-Report: SpamAssassin version 3.0.4 on pentafluge.infradead.org summary: Content analysis details: (2.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.1 RCVD_IN_SORBS_DUL RBL: SORBS: sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 2.8 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 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 > > Which is indeed a further disincentive against shared page tables. > > Or shared pagetables a disincentive to randomizing the mmap space ;-) > They're incompatible, but you could be left to choose one or the other > via config option. > > 3% on "a certain industry-standard database benchmark" (cough) is huge, > and we expect the benefit for PPC64 will be larger as we can share the > underlying hardware PTEs without TLB flushing as well. > surely the benchmark people know that the database in question always mmaps the shared area at the address where the first one started it? (if not, could make it so ;)