Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757404AbXHZExY (ORCPT ); Sun, 26 Aug 2007 00:53:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752074AbXHZExP (ORCPT ); Sun, 26 Aug 2007 00:53:15 -0400 Received: from mx1.redhat.com ([66.187.233.31]:58047 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751998AbXHZExO (ORCPT ); Sun, 26 Aug 2007 00:53:14 -0400 Message-ID: <46D10721.7070406@redhat.com> Date: Sun, 26 Aug 2007 00:52:49 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 1.5.0.7 (X11/20061008) MIME-Version: 1.0 To: Christoph Lameter CC: Peter Zijlstra , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [RFC 0/7] Postphone reclaim laundry to write at high water marks References: <20070820215040.937296148@sgi.com> <1187692586.6114.211.camel@twins> <1187730812.5463.12.camel@lappy> <1187734144.5463.35.camel@lappy> <1187766156.6114.280.camel@twins> <1187813025.5463.85.camel@lappy> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1223 Lines: 30 Christoph Lameter wrote: > On Wed, 22 Aug 2007, Peter Zijlstra wrote: > >>> That is an extreme case that AFAIK we currently ignore and could be >>> avoided with some effort. >> Its not extreme, not even rare, and its handled now. Its what >> PF_MEMALLOC is for. > > No its not. If you have all pages allocated as anonymous pages and your > writeout requires more pages than available in the reserves then you are > screwed either way regardless if you have PF_MEMALLOC set or not. Only if the _first_ writeout needs more pages. If the sum of all writeouts need more pages than you have available, that is fine. After all, buffer heads and some other metadata is freed on IO completion. Recursive reclaim will also be able to free the data pages after IO completion, and really fix the problem. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/