From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 14 Aug 2001 08:59:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 14 Aug 2001 08:58:59 -0400 Received: from humbolt.nl.linux.org ([131.211.28.48]:12037 "EHLO humbolt.nl.linux.org") by vger.kernel.org with ESMTP id ; Tue, 14 Aug 2001 08:58:51 -0400 Content-Type: text/plain; charset=US-ASCII From: Daniel Phillips To: Rik van Riel , Alan Cox Subject: Re: VM working much better in 2.4.8 than before Date: Tue, 14 Aug 2001 15:03:51 +0200 X-Mailer: KMail [version 1.3] Cc: Helge Hafting , In-Reply-To: In-Reply-To: MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <20010814125859Z16031-1231+838@humbolt.nl.linux.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On August 13, 2001 05:52 pm, Rik van Riel wrote: > On Mon, 13 Aug 2001, Alan Cox wrote: > > > Yes, those would be the expected effects of use-once, in fact it was > > > "morning after updatedb" question that got me started on it. > > > > updatedb is also absolutely fine if you just work with the existing VM > > and up the inode pressure a little. I'm still very unconvinced by > > use-once. > > Use-once has a number of theoretical disadvantages too: > > 1) newly read in pages are evicted earlier, this means > readahead pages will either evict each other or the > amount of readahead done might need to be shrunk > -- the current readahead code is not prepared for this, > use-once could lead to more disk seeks being done Have you actually seen this happening? > 2) since we add new pages to the inactive list, VM > balancing is faced with a really strange situation ;) > > Yes, these things are solvable, but not without redesigning > major parts of the VM balancing to do things which have never > been done before. I'm not sure 2.4 is the time to do that. -- Daniel