From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964807AbWBGAlt (ORCPT ); Mon, 6 Feb 2006 19:41:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964900AbWBGAlt (ORCPT ); Mon, 6 Feb 2006 19:41:49 -0500 Received: from MAIL.13thfloor.at ([212.16.62.50]:24742 "EHLO mail.13thfloor.at") by vger.kernel.org with ESMTP id S964807AbWBGAls (ORCPT ); Mon, 6 Feb 2006 19:41:48 -0500 Date: Tue, 7 Feb 2006 01:41:47 +0100 From: Herbert Poetzl To: Jan Engelhardt Cc: Arjan van de Ven , Mark Lord , Ulrich Mueller , linux-kernel@vger.kernel.org, Jens Axboe , Linus Torvalds , Byron Stanoszek , Ingo Molnar , Andrew Morton Subject: Re: [PATCH ] VMSPLIT config options (with default config fixed) Message-ID: <20060207004147.GA21620@MAIL.13thfloor.at> Mail-Followup-To: Jan Engelhardt , Arjan van de Ven , Mark Lord , Ulrich Mueller , linux-kernel@vger.kernel.org, Jens Axboe , Linus Torvalds , Byron Stanoszek , Ingo Molnar , Andrew Morton References: <43C40803.2000106@rtr.ca> <20060201222314.GA26081@MAIL.13thfloor.at> <43E3DB99.9020604@rtr.ca> <1139153913.3131.42.camel@laptopd505.fenrus.org> <1139174355.3131.50.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 06, 2006 at 03:56:34PM +0100, Jan Engelhardt wrote: > >> >> What userspace programs do depend on it? > >> > > >> >there is a lot of userspace that assumes they can do 2Gb or even close > >> >to 3Gb of memory allocations. Databases, java, basically anything with > >> >threads. Sure for most of these its a configuration option to reduce > >> >this, but that still doesn't mean it's a good idea to change from the > >> >existing behavior... > >> > > >> Not to mention that these (almost(*)) fail anyway when you have less than 2 > >> GB of RAM. > > > >it's not really overcommit... it can also be file mmaps or shared mmaps > >of say tmpfs files (the later is common with oracle actually) > > So, just as I did in the sample patch, the manual split shall depend on > EMBEDDED. Those who run fat databases with big malloc/mmap assumptions > don't probably belong to the group using CONFIG_EMBEDDED. *sigh* well, the embeded folks are unlikely to have 1-3GB why not use EXPERIMENTAL if you 'think' the option will hurt the database folks who do not know to configure their kernel ... best, Herbert > Jan Engelhardt > --