Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753272AbbFVTJI (ORCPT ); Mon, 22 Jun 2015 15:09:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54113 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751511AbbFVTJE (ORCPT ); Mon, 22 Jun 2015 15:09:04 -0400 From: Jeff Moyer To: Dan Williams Cc: Christoph Hellwig , Jens Axboe , "linux-nvdimm\@lists.01.org" , Neil Brown , Greg KH , "linux-kernel\@vger.kernel.org" , Ingo Molnar , Linux ACPI , linux-fsdevel Subject: Re: [PATCH 02/15] libnvdimm: infrastructure for btt devices References: <20150617235209.12943.24419.stgit@dwillia2-desk3.amr.corp.intel.com> <20150617235458.12943.23425.stgit@dwillia2-desk3.amr.corp.intel.com> <20150622163453.GA9187@lst.de> <20150622164837.GB9393@lst.de> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Mon, 22 Jun 2015 15:09:02 -0400 In-Reply-To: (Dan Williams's message of "Mon, 22 Jun 2015 12:02:54 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1523 Lines: 38 Dan Williams writes: > On Mon, Jun 22, 2015 at 11:32 AM, Jeff Moyer wrote: >> Christoph Hellwig writes: >> >>> On Mon, Jun 22, 2015 at 09:48:03AM -0700, Dan Williams wrote: >>>> Only if you abandon BTT on partitions, which at this point it seems >>>> you're boldly committed to doing. It's unacceptable to drop BTT on >>>> the floor so I'll take a look at making BTT per-disk only for 4.2. >>> >>> If by partitions you mean block layer partitions: yes. If by partitions >>> you mean subdivision of nvdimms: no. >> >> How will this subdivision be recorded? Not all NVDIMMs support the >> label specification. > > ...and the ones that do only use labels for resolving aliasing, not > partitioning. > >> Sysadmins are already familiar with partitions; I'm not sure why we'd >> deviate from that here. What am I missing? > > I don't see the need to re-invent partitioning which is the path this > requested rework is putting us on... > > However, when the need arises for smaller granularity BTT we can have > the partition fight then. To be clear, I believe that need is already > here today, but I'm not in a position to push that agenda at this late > date. The xfs example is enough to convince me that we need to support btt on a partition right now. Otherwise, for RHEL at least, dax on xfs simply won't be supported. -Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/