From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 6 Aug 2001 16:12:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 6 Aug 2001 16:12:14 -0400 Received: from roc-24-169-102-121.rochester.rr.com ([24.169.102.121]:63246 "EHLO roc-24-169-102-121.rochester.rr.com") by vger.kernel.org with ESMTP id ; Mon, 6 Aug 2001 16:11:57 -0400 Date: Mon, 06 Aug 2001 16:12:00 -0400 From: Chris Mason To: Daniel Phillips , linux-kernel@vger.kernel.org cc: linux-mm@kvack.org Subject: Re: [RFC] using writepage to start io Message-ID: <755760000.997128720@tiny> In-Reply-To: <0108062145120I.00294@starship> X-Mailer: Mulberry/2.0.8 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Monday, August 06, 2001 09:45:12 PM +0200 Daniel Phillips wrote: >> Almost ;-) memory pressure doesn't need to care about how long a >> buffer has been dirty, that's kupdate's job. kupdate doesn't care if >> the buffer it is writing is a good candidate for freeing, that's taken >> care of elsewhere. The two never need to talk (aside from >> optimizations). > > My point is, they should talk, in fact they should be the same function. > It's never right for bdflush to submit younger buffers when there are > dirty buffers whose flush time has already passed. > Grin, we're talking in circles. My point is that by having two threads, bdflush is allowed to skip over older buffers in favor of younger ones because somebody else is responsible for writing the older ones out. Take away the kupdate thread and bdflush must write the older buffer. I believe this limits optimizations, unless kswapd is changed to handle all memory pressure flushes. -chris