Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262741AbVAFFqy (ORCPT ); Thu, 6 Jan 2005 00:46:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262742AbVAFFqy (ORCPT ); Thu, 6 Jan 2005 00:46:54 -0500 Received: from ppp-217-133-42-200.cust-adsl.tiscali.it ([217.133.42.200]:57159 "EHLO dualathlon.random") by vger.kernel.org with ESMTP id S262741AbVAFFqs (ORCPT ); Thu, 6 Jan 2005 00:46:48 -0500 Date: Thu, 6 Jan 2005 06:46:59 +0100 From: Andrea Arcangeli To: Andrew Morton Cc: Nick Piggin , riel@redhat.com, marcelo.tosatti@cyclades.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH][5/?] count writeback pages in nr_scanned Message-ID: <20050106054659.GS4597@dualathlon.random> References: <41DCB577.9000205@yahoo.com.au> <20050105202611.65eb82cf.akpm@osdl.org> <41DCC014.80007@yahoo.com.au> <20050105204706.0781d672.akpm@osdl.org> <20050106045932.GN4597@dualathlon.random> <20050105210539.19807337.akpm@osdl.org> <20050106051707.GP4597@dualathlon.random> <41DCCA68.3020100@yahoo.com.au> <20050105213207.721b1aae.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050105213207.721b1aae.akpm@osdl.org> 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 Content-Length: 1263 Lines: 26 On Wed, Jan 05, 2005 at 09:32:07PM -0800, Andrew Morton wrote: > > > The slight improvement you suggested of waiting on _any_ random > > > PG_writeback to go away (instead of one particular one as I did in 2.4) > > It's a HUGE improvement. I didn't want to question the improvement in wall clock time terms. > For the third time: "fixing" this involves delivering a wakeup to all zones > in the page's classzone in end_page_writeback(), and passing the zone* into > blk_congestion_wait(). Only deliver the wakeup on every Nth page to get a > bit of batching and to reduce CPU consumption. Then demonstrating that the > change actually improves something. Since I cannot reproduce oom kills with writeback, I sure can't demonstrate it on bare hardware with unmodified kernel. But I dislike code that works by luck, and sure I could demonstrate it if I bothered to write an artificial testcase on simulated hardware. This is the only reason I mentioned this bug in the first place, not because I'm reproducing it. - 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/