From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262307AbVAUHIq (ORCPT ); Fri, 21 Jan 2005 02:08:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262155AbVAUHIq (ORCPT ); Fri, 21 Jan 2005 02:08:46 -0500 Received: from one.firstfloor.org ([213.235.205.2]:35532 "EHLO one.firstfloor.org") by vger.kernel.org with ESMTP id S262299AbVAUHI2 (ORCPT ); Fri, 21 Jan 2005 02:08:28 -0500 To: Andrew Morton Cc: andrea@suse.de, linux-kernel@vger.kernel.org Subject: Re: OOM fixes 2/5 References: <20050121054840.GA12647@dualathlon.random> <20050121054916.GB12647@dualathlon.random> <20050120222056.61b8b1c3.akpm@osdl.org> <1106289375.5171.7.camel@npiggin-nld.site> <20050120224645.3351d22c.akpm@osdl.org> From: Andi Kleen Date: Fri, 21 Jan 2005 08:08:21 +0100 In-Reply-To: <20050120224645.3351d22c.akpm@osdl.org> (Andrew Morton's message of "Thu, 20 Jan 2005 22:46:45 -0800") Message-ID: User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton writes: > Just that it throws away a bunch of potentially usable memory. In three > years I've seen zero reports of any problems which would have been solved > by increasing the protection ratio. We ran into a big problem with this on x86-64. The SUSE installer would load the floppy driver during installation. Floppy driver would try to allocate some pages with GFP_DMA and on a small memory x86-64 system (256-512MB) the OOM killer would always start to kill things trying to free some DMA pages. This was quite a show stopper because you effectively couldn't install. So at least for GFP_DMA it seems to be definitely needed. -Andi