From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261558AbULYUEq (ORCPT ); Sat, 25 Dec 2004 15:04:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261560AbULYUEq (ORCPT ); Sat, 25 Dec 2004 15:04:46 -0500 Received: from mail-relay-1.tiscali.it ([213.205.33.41]:49553 "EHLO mail-relay-1.tiscali.it") by vger.kernel.org with ESMTP id S261558AbULYUEm (ORCPT ); Sat, 25 Dec 2004 15:04:42 -0500 Date: Sat, 25 Dec 2004 21:03:49 +0100 From: Andrea Arcangeli To: William Lee Irwin III Cc: Rik van Riel , Andrew Morton , linux-kernel@vger.kernel.org, Robert_Hentosh@Dell.com, Con Kolivas Subject: Re: [PATCH][1/2] adjust dirty threshold for lowmem-only mappings Message-ID: <20041225200349.GA11116@dualathlon.random> References: <20041220125443.091a911b.akpm@osdl.org> <20041224160136.GG4459@dualathlon.random> <20041224164024.GK4459@dualathlon.random> <20041225020707.GQ13747@dualathlon.random> <20041225190710.GZ771@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20041225190710.GZ771@holomorphy.com> X-GPG-Key: 1024D/68B9CB43 13D9 8355 295F 4823 7C49 C012 DFA1 686E 68B9 CB43 X-PGP-Key: 1024R/CB4660B9 CC A0 71 81 F4 A0 63 AC C0 4B 81 1D 8C 15 C8 E5 User-Agent: Mutt/1.5.6i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 25, 2004 at 11:07:10AM -0800, William Lee Irwin III wrote: > Lifting the artificial lowmem restrictions on blockdev mappings > (thereby nuking mapping->gfp_mask altogether) would resolve a number of > problems, not that anything making that much sense could ever happen. I recall that such restriction is needed only for the buffercache, or you'd need to change _all_ the fs to kmap before accessing metadata (this is partly already happening for the dir in pagecache, but not for everything else). Whatever the problem is (assuming there's really a problem in the write throttling) it isn't going away by eliminating that restriction. Just think booting with mem=800M, it would run into the same issue that happens right now with the artificial limitation and >=1G of ram. 2.4 has the same limitation and it has no problem with write throttling (and from my part 2.6 is working fine too with the 4 patches I posted, it's not me being able to reproduce it).