From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755780Ab0CHUWR (ORCPT ); Mon, 8 Mar 2010 15:22:17 -0500 Received: from rcsinet11.oracle.com ([148.87.113.123]:55069 "EHLO rcsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755714Ab0CHUWG (ORCPT ); Mon, 8 Mar 2010 15:22:06 -0500 To: "H. Peter Anvin" Cc: "Martin K. Petersen" , James Bottomley , Tejun Heo , "linux-ide\@vger.kernel.org" , lkml , Daniel Taylor , Jeff Garzik , Mark Lord , tytso@mit.edu, hirofumi@mail.parknet.co.jp, Andrew Morton , Alan Cox , irtiger@gmail.com, Matthew Wilcox , aschnell@suse.de, knikanth@suse.de, jdelvare@suse.de Subject: Re: ATA 4 KiB sector issues. From: "Martin K. Petersen" Organization: Oracle References: <4B947393.2050002@kernel.org> <1268031640.4389.11.camel@mulgrave.site> <4B9546E6.6050006@zytor.com> Date: Mon, 08 Mar 2010 15:19:05 -0500 In-Reply-To: <4B9546E6.6050006@zytor.com> (H. Peter Anvin's message of "Mon, 08 Mar 2010 10:50:14 -0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Source-IP: acsmt354.oracle.com [141.146.40.154] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090206.4B955C20.00D8:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>>>> "hpa" == H Peter Anvin writes: hpa> On the flipside, though, there really is very little net benefit to hpa> 4K as opposed to 512 byte logical sectors: the additional protocol hpa> overhead is relatively minimal, and as long as writes are aligned hpa> full blocks, there shouldn't be any additional overhead on either hpa> the OS or the drive side. On the plus side, you get full hpa> compatibility with the existing software stack. The equation hpa> really seems rather simple. 4KB sectors are not a win for anybody except the drive vendors. There is a push in the industry right now to keep the 512-byte logical blocks forever. The first step would be to report misaligned accesses or accesses that are not a multiple of the physical block size. Second step would be to eventually reject any write that's not a properly aligned multiple of the physical block size. -- Martin K. Petersen Oracle Linux Engineering