From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751485AbcFXPyq (ORCPT ); Fri, 24 Jun 2016 11:54:46 -0400 Received: from mail-by2on0126.outbound.protection.outlook.com ([207.46.100.126]:6784 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751063AbcFXPyn (ORCPT ); Fri, 24 Jun 2016 11:54:43 -0400 From: "Kani, Toshimitsu" To: "snitzer@redhat.com" CC: "linux-kernel@vger.kernel.org" , "linux-nvdimm@ml01.01.org" , "viro@zeniv.linux.org.uk" , "dan.j.williams@intel.com" , "axboe@kernel.dk" , "ross.zwisler@linux.intel.com" , "dm-devel@redhat.com" , "yigal@plexistor.com" Subject: Re: [PATCH v3 3/4] dm: add infrastructure for DAX support Thread-Topic: [PATCH v3 3/4] dm: add infrastructure for DAX support Thread-Index: AQHRzZMZVThpDHQ2vEakVTOObT7oI5/3tPUAgAAlMACAAOgkAA== Date: Fri, 24 Jun 2016 15:40:24 +0000 Message-ID: <1466782822.3504.391.camel@hpe.com> References: <1466715953-40692-1-git-send-email-snitzer@redhat.com> <1466715953-40692-4-git-send-email-snitzer@redhat.com> <1466724984.3504.380.camel@hpe.com> <20160624014930.GA10540@redhat.com> In-Reply-To: <20160624014930.GA10540@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=toshi.kani@hpe.com; x-originating-ip: [15.219.163.9] x-ms-office365-filtering-correlation-id: d51486d6-ef61-4e8a-9473-08d39c45dbec x-microsoft-exchange-diagnostics: 1;CS1PR84MB0005;6:vGJA1J9FvYMoTj/NZUHa3k3C2PYKeXYr3mIP4EY1doTFGV1JLda+TSdrsLSavGAOYa/t2apgUTvrhAbqVigIxjylEPlyE0d7y1j5IP+qhyRaqwVeUx2c9HyWsspwN6eNNIGAnmiqzbYode9Jj4hWUkRXKKHSIg6arsEiP1z4DrZmL3Ysj9KAFDUJCCPExyfAKRB24S2vNmVYU1Yy0VcTsN9LO8+7ZZR3kepHqjor82sL+qhg8a2xs/GBS1I8Dy06pR315WUN16/mDWueasjpFS1qoAoGDbJRXcXLUNVNSGHTHS2cPVT7FZZKQ1T86uO5;5:duLQdJgLja/k9+wuer9pUxpo0GF9K9R8axkARWvrIWwECoXvjiGh6FoHkbqkD+deA7hrcXcgR6129k0tpbEqW9RZZL259ynohQItyPTCFArQGZN+fkCdEW7vUduvFk7UGLmU5y1HFhTqsyXUN1Piag==;24:Ih1AyLpqqiSPft/2FitEbdhLIaGgrgb4UfqRpbOiGrafvxFrmMtb7dkX9UN/AmOIp/LUWXjUsjGDqPJ2UwTXNQNZ+SJvhAhSSIP5fptQ7FI=;7:XKVbmNCrvXtEfEXSqqxOoMQc0MnkTcg4BRKezshECR41OjYx6e+ZJ8pmrY+0sZiDrv9La3Bs1O5uG2pY6ZXTdkYN73N8r06UfyjCkH4PzqDQUfrRi/uccv7HZOO7i7as4+oOvwRZhPh6AzBxqn4wakLK+uw4hs9ZERzEhtMcZoMpSJJcifvAS+GitPedtvl2VIeom4sn8aIkvTAKc/aZTNKeasrkmCYo/QfEXOboKlWHQPK1kiuj5feXhx5GKFZ2JedMh/s+Wnck7jjz8h48sg== x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0005; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(227479698468861); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(601004)(2401047)(8121501046)(5005006)(10201501046)(3002001);SRVR:CS1PR84MB0005;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0005; x-forefront-prvs: 0983EAD6B2 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(7916002)(377424004)(76104003)(189002)(51914003)(24454002)(199003)(7846002)(8676002)(3660700001)(2906002)(7736002)(99286002)(1730700003)(81156014)(2351001)(3280700002)(81166006)(4326007)(110136002)(97736004)(189998001)(5640700001)(305945005)(122556002)(10400500002)(5002640100001)(106356001)(103116003)(6116002)(11100500001)(3846002)(36756003)(586003)(33646002)(2900100001)(87936001)(2501003)(92566002)(68736007)(76176999)(54356999)(8936002)(106116001)(50986999)(105586002)(19580405001)(19580395003)(101416001)(86362001)(93886004)(2950100001)(77096005)(66066001)(102836003);DIR:OUT;SFP:1102;SCL:1;SRVR:CS1PR84MB0005;H:CS1PR84MB0005.NAMPRD84.PROD.OUTLOOK.COM;FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <18CC78150207B44888EC52FD807E6F55@NAMPRD84.PROD.OUTLOOK.COM> MIME-Version: 1.0 X-OriginatorOrg: hpe.com X-MS-Exchange-CrossTenant-originalarrivaltime: 24 Jun 2016 15:40:24.3991 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 105b2061-b669-4b31-92ac-24d304d195dc X-MS-Exchange-Transport-CrossTenantHeadersStamped: CS1PR84MB0005 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id u5OFsolo026011 On Thu, 2016-06-23 at 21:49 -0400, Mike Snitzer wrote: > On Thu, Jun 23 2016 at  7:36pm -0400, > Kani, Toshimitsu wrote:  : > > Thanks for the update.  I have a question about the above change.  Targets > > may have their own parameters.  For instance, dm-stripe has 'chunk_size', > > which is checked in stripe_ctr().  DAX adds additional restriction that > > chunk_size needs to be aligned by page size.  So, I think we need to keep > > target responsible to verify if DAX can be supported.  What do you think? > > We've never had to concern the dm-stripe target with hardware > specific chunk_size validation.  The user is able to specify the > chunk_size via lvm2's lvcreate -I argument.  Yes this gives users enough > rope to hang themselves but it is very easy to configure a dm-stripe > device with the appropriate chunk size (PAGE_SIZE) from userspace. > > But lvm2 could even be trained to make sure the chunk_size is a factor > of physical_block_size (PAGE_SIZE in the case of pmem) if the underlying > devices export queue/dax=1 lvcreate -I only allows multiple of page size, so we are OK with lvm2.  I was wondering if the check in lvm2 is enough.  Are there any other tools that may be used to configure stripe size?  Can we trust userspace on this? Thanks, -Toshi