Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756077AbZC1ARS (ORCPT ); Fri, 27 Mar 2009 20:17:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752702AbZC1ARC (ORCPT ); Fri, 27 Mar 2009 20:17:02 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:46540 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752448AbZC1ARA (ORCPT ); Fri, 27 Mar 2009 20:17:00 -0400 Date: Sat, 28 Mar 2009 00:14:32 +0000 From: Alan Cox To: Jeff Garzik Cc: Christoph Hellwig , Theodore Tso , Jens Axboe , Linus Torvalds , Ingo Molnar , Arjan van de Ven , Andrew Morton , Peter Zijlstra , Nick Piggin , David Rees , Jesper Krogh , Linux Kernel Mailing List Subject: Re: Linux 2.6.29 Message-ID: <20090328001432.5dd5f10f@lxorguk.ukuu.org.uk> In-Reply-To: <49CD394B.9080903@garzik.org> References: <20090324184549.GE32307@mit.edu> <49C93AB0.6070300@garzik.org> <20090325093913.GJ27476@kernel.dk> <49CA86BD.6060205@garzik.org> <20090325194341.GB27476@kernel.dk> <49CA9346.6040108@garzik.org> <20090327075723.GT27476@kernel.dk> <20090327141333.GS6239@mit.edu> <20090327143543.GA17541@infradead.org> <49CD394B.9080903@garzik.org> X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; x86_64-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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1017 Lines: 22 On Fri, 27 Mar 2009 16:38:35 -0400 Jeff Garzik wrote: > Christoph Hellwig wrote: > > And please add a tuneable for the flush. Preferable a generic one at > > the block device layer instead of the current mess where every > > filesystem has a slightly different option for barrier usage. > > At the very least, IMO the block layer should be able to notice when > barriers need not be translated into cache flushes. Most notably when > wb cache is disabled on the drive, something easy to auto-detect, but > probably a manual switch also, for people with enterprise battery-backed > storage and such. The storage drivers for those cases already generally know this and treat cache flush requests as "has hit nvram", even the non enterprise ones. -- 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/