From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161202AbXDMXcq (ORCPT ); Fri, 13 Apr 2007 19:32:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161260AbXDMXcq (ORCPT ); Fri, 13 Apr 2007 19:32:46 -0400 Received: from smtp.osdl.org ([65.172.181.24]:60828 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161202AbXDMXcp (ORCPT ); Fri, 13 Apr 2007 19:32:45 -0400 Date: Fri, 13 Apr 2007 16:32:42 -0700 From: Andrew Morton To: William Lee Irwin III Cc: Jason Lunz , Cameron Schaus , linux-kernel@vger.kernel.org Subject: Re: 2.6.20 OOM with 8Gb RAM Message-Id: <20070413163242.7d9283e1.akpm@linux-foundation.org> In-Reply-To: <20070413225433.GV2986@holomorphy.com> References: <20070412173830.GA31323@schaus.ca> <20070412121553.c7fd3249.akpm@linux-foundation.org> <20070413223935.GA6783@metaxa.reflex> <20070413154653.21fdb914.akpm@linux-foundation.org> <20070413225433.GV2986@holomorphy.com> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 13 Apr 2007 15:54:33 -0700 William Lee Irwin III wrote: > On Fri, Apr 13, 2007 at 03:46:53PM -0700, Andrew Morton wrote: > > It's just weird - it exploits internal knowledge of VFS behaviour, diddles > > with pagecache within a fake disk strategy handler, etc. > > Furthermore, because it pretends to be a block device, the VFS will not use > > highmem pages when accessing the ramdisk. So the 8GB machine will go splat > > with only 800MB of ramdisk. > > ramfs is much cleaner and does not have that limitation. > > After all this time, bdevs are still lowmem etc. Crying shame. One would need to hunt down every use of b_data in filesystems and switch them to kmap the page. Possibly it could be done on a per-fs basis.