From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 8/8] vm: Add an tuning knob for vm.max_writeback_pages Date: Tue, 1 Sep 2009 14:44:55 -0400 Message-ID: <20090901184455.GA27294@infradead.org> References: <1251803946-9243-1-git-send-email-jens.axboe@oracle.com> <1251803946-9243-9-git-send-email-jens.axboe@oracle.com> <1251830335.8502.17.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jens Axboe , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, chris.mason@oracle.com, david@fromorbit.com, hch@infradead.org, tytso@mit.edu, akpm@linux-foundation.org, jack@suse.cz To: Peter Zijlstra Return-path: Received: from bombadil.infradead.org ([18.85.46.34]:54143 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751848AbZIASoy (ORCPT ); Tue, 1 Sep 2009 14:44:54 -0400 Content-Disposition: inline In-Reply-To: <1251830335.8502.17.camel@laptop> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Sep 01, 2009 at 08:38:55PM +0200, Peter Zijlstra wrote: > Do we really need a tunable for this? It will make increasing it in the field a lot easier. And having deal with really large systems I have the fear that there are I/O topologies outhere for which every "reasonable" value is too low. > I guess we need a limit to avoid it writing out everything, but can't we > have something automagic? Some automatic adjustment would be nice. But finding the right auto tuning will be an interesting exercise.