From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261589AbUBYXB7 (ORCPT ); Wed, 25 Feb 2004 18:01:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261575AbUBYW6M (ORCPT ); Wed, 25 Feb 2004 17:58:12 -0500 Received: from fw.osdl.org ([65.172.181.6]:4581 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261589AbUBYW5E (ORCPT ); Wed, 25 Feb 2004 17:57:04 -0500 Subject: Re: [PATCH 2.6.3-mm3] serialize_writeback_fdatawait patch From: Daniel McNeil To: Andrew Morton Cc: Linux Kernel Mailing List , "linux-aio@kvack.org" In-Reply-To: <20040224174354.517b1d23.akpm@osdl.org> References: <20040222172200.1d6bdfae.akpm@osdl.org> <1077671733.1956.247.camel@ibm-c.pdx.osdl.net> <20040224174354.517b1d23.akpm@osdl.org> Content-Type: text/plain Organization: Message-Id: <1077749819.1956.271.camel@ibm-c.pdx.osdl.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.2.2 (1.2.2-5) Date: 25 Feb 2004 14:56:59 -0800 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2004-02-24 at 17:43, Andrew Morton wrote: > > hm, OK. I've converted all the down_read_trylock() things into a sinple > down_read(), to address the pdflush-busywait problem which Hugh identified. > The other thing we could do is add a wbc->encountered_congestion = 1 if the down_read_trylock() fails and then check for that to prevent the busywait problem. > This does mean that pdflush can get blocked by ongoing sync activity but > that's probably insignificant and we have per-spindle pdflush collision > avoidance which will help a bit. > > Call me lazy, but could you please work out the ranking of wb_rwsem with > respect to the other VFS locks, update the locking documentation in > mm/filemap.c and make sure that we're actually adhering to it? Thanks. Ok. I'm looking at this. Daniel