From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: I/O topology fixes for big physical block size Date: Mon, 27 Sep 2010 18:14:52 -0400 Message-ID: References: <1285605664-27027-1-git-send-email-martin.petersen@oracle.com> <4CA0CC38.5010804@fusionio.com> <20100927172309.GA13874@redhat.com> <1285624684.2888.120.camel@mulgrave.site> <4CA114A3.4010202@fusionio.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from rcsinet10.oracle.com ([148.87.113.121]:42323 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756026Ab0I0WQF (ORCPT ); Mon, 27 Sep 2010 18:16:05 -0400 In-Reply-To: <4CA114A3.4010202@fusionio.com> (Jens Axboe's message of "Tue, 28 Sep 2010 07:03:15 +0900") Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe Cc: James Bottomley , Mike Snitzer , "Martin K. Petersen" , "linux-scsi@vger.kernel.org" >>>>> "Jens" == Jens Axboe writes: Jens> Yes, from a correctness point of view it doesn't matter, but when Jens> people go looking up fixes for whatever reason, it's much better Jens> to include such a fix in the original patch so it's not missed. I have talked to a few standards people today. They are of the opinion that the device's usage of the physical block exponent is incorrect. And that the device must provide the Block Limits and the TP VPD if thin provisioning is enabled. However, devices with 8KiB physical blocks are shipping and 16KiB ditto are right around the corner. Which says to me that it's important to report the correct thing to userland so we can cause allocators to align on the right boundaries, etc. If we artificially clamp the physical block size parameter in the kernel we are losing information. Note that there are no kernel users of the physical block size parameter at all. -- Martin K. Petersen Oracle Linux Engineering