Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261403AbUJZUYz (ORCPT ); Tue, 26 Oct 2004 16:24:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261426AbUJZUXD (ORCPT ); Tue, 26 Oct 2004 16:23:03 -0400 Received: from fw.osdl.org ([65.172.181.6]:29133 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261403AbUJZUU5 (ORCPT ); Tue, 26 Oct 2004 16:20:57 -0400 Date: Tue, 26 Oct 2004 13:18:42 -0700 From: Andrew Morton To: Mingming Cao Cc: ray-lk@madrabbit.org, sct@redhat.com, pbadari@us.ibm.com, linux-kernel@vger.kernel.org, ext2-devel@lists.sourceforge.net Subject: Re: [Ext2-devel] Re: [PATCH 2/3] ext3 reservation allow turn off for specifed file Message-Id: <20041026131842.45b99834.akpm@osdl.org> In-Reply-To: <1098809607.8919.7466.camel@w-ming2.beaverton.ibm.com> References: <1097846833.1968.88.camel@sisko.scot.redhat.com> <1097856114.4591.28.camel@localhost.localdomain> <1097858401.1968.148.camel@sisko.scot.redhat.com> <1097872144.4591.54.camel@localhost.localdomain> <1097878826.1968.162.camel@sisko.scot.redhat.com> <109787 <1098147705.8803.1084.camel@w-ming2.beaverton.ibm.com> <1098294941.18850.4.camel@orca.madrabbit.org> <1098736389.9692.7243.camel@w-ming2.beaverton.ibm.com> <1098745548.9754.7427.camel@w-ming2.beaverton.ibm.com> <20041025164516.1f02bb9f.akpm@osdl.org> <1098809607.8919.7466.camel@w-ming2.beaverton.ibm.com> X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1224 Lines: 24 Mingming Cao wrote: > > > I wonder how important this optimisation really is? I bet no applications > > are using posix_fadvise(POSIX_FADV_RANDOM) anyway. > > > I don't know if there is application using the POSIX_FADV_RANDOM. No? If > this is the truth, I think we don't need this optimization at present. > Logically reservation does not benefit seeky random write, but there is > no benchmark showing performance issue so far. We have already provided > ways for applications turn off reservation through the existing ioctl > for specified file and -o noreservation mount option for the whole > filesystem. Well we definitely don't want to be encouraging application developers to be adding ext3-specific ioctls. So we need to work out if any applications can get significant benefit from manually disabling reservations and if so, wire up fadvise() into filesystems and do it that way. Do you know if disabling reservations helps any workloads? - 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/