From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kani, Toshimitsu" Subject: Re: [PATCH v3 3/4] dm: add infrastructure for DAX support 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> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: In-Reply-To: <20160624014930.GA10540-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Content-Language: en-US Content-ID: <18CC78150207B44888EC52FD807E6F55-mmYPd6ayCNGroOM5E8FhRbjFIynDaujOfM0AETQt39g@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: "snitzer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" Cc: "axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org" , "linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org" , "viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org" List-Id: dm-devel.ids T24gVGh1LCAyMDE2LTA2LTIzIGF0IDIxOjQ5IC0wNDAwLCBNaWtlIFNuaXR6ZXIgd3JvdGU6DQo+ IE9uIFRodSwgSnVuIDIzIDIwMTYgYXTCoMKgNzozNnBtIC0wNDAwLA0KPiBLYW5pLCBUb3NoaW1p dHN1IDx0b3NoaS5rYW5pQGhwZS5jb20+IHdyb3RlOg0KwqA6DQo+ID4gVGhhbmtzIGZvciB0aGUg dXBkYXRlLiDCoEkgaGF2ZSBhIHF1ZXN0aW9uIGFib3V0IHRoZSBhYm92ZSBjaGFuZ2UuIMKgVGFy Z2V0cw0KPiA+IG1heSBoYXZlIHRoZWlyIG93biBwYXJhbWV0ZXJzLiDCoEZvciBpbnN0YW5jZSwg ZG0tc3RyaXBlIGhhcyAnY2h1bmtfc2l6ZScsDQo+ID4gd2hpY2ggaXMgY2hlY2tlZCBpbiBzdHJp cGVfY3RyKCkuIMKgREFYIGFkZHMgYWRkaXRpb25hbCByZXN0cmljdGlvbiB0aGF0DQo+ID4gY2h1 bmtfc2l6ZSBuZWVkcyB0byBiZSBhbGlnbmVkIGJ5IHBhZ2Ugc2l6ZS4gwqBTbywgSSB0aGluayB3 ZSBuZWVkIHRvIGtlZXANCj4gPiB0YXJnZXQgcmVzcG9uc2libGUgdG8gdmVyaWZ5IGlmIERBWCBj YW4gYmUgc3VwcG9ydGVkLiDCoFdoYXQgZG8geW91IHRoaW5rPw0KPg0KPiBXZSd2ZSBuZXZlciBo YWQgdG8gY29uY2VybiB0aGUgZG0tc3RyaXBlIHRhcmdldCB3aXRoIGhhcmR3YXJlDQo+IHNwZWNp ZmljIGNodW5rX3NpemUgdmFsaWRhdGlvbi7CoMKgVGhlIHVzZXIgaXMgYWJsZSB0byBzcGVjaWZ5 IHRoZQ0KPiBjaHVua19zaXplIHZpYSBsdm0yJ3MgbHZjcmVhdGUgLUkgYXJndW1lbnQuwqDCoFll cyB0aGlzIGdpdmVzIHVzZXJzIGVub3VnaA0KPiByb3BlIHRvIGhhbmcgdGhlbXNlbHZlcyBidXQg aXQgaXMgdmVyeSBlYXN5IHRvIGNvbmZpZ3VyZSBhIGRtLXN0cmlwZQ0KPiBkZXZpY2Ugd2l0aCB0 aGUgYXBwcm9wcmlhdGUgY2h1bmsgc2l6ZSAoUEFHRV9TSVpFKSBmcm9tIHVzZXJzcGFjZS4NCj4g DQo+IEJ1dCBsdm0yIGNvdWxkIGV2ZW4gYmUgdHJhaW5lZCB0byBtYWtlIHN1cmUgdGhlIGNodW5r X3NpemUgaXMgYSBmYWN0b3INCj4gb2YgcGh5c2ljYWxfYmxvY2tfc2l6ZSAoUEFHRV9TSVpFIGlu IHRoZSBjYXNlIG9mIHBtZW0pIGlmIHRoZSB1bmRlcmx5aW5nDQo+IGRldmljZXMgZXhwb3J0IHF1 ZXVlL2RheD0xDQoNCmx2Y3JlYXRlwqAtSSBvbmx5IGFsbG93cyBtdWx0aXBsZSBvZiBwYWdlIHNp emUsIHNvIHdlIGFyZSBPSyB3aXRoIGx2bTIuIMKgSSB3YXMNCndvbmRlcmluZyBpZiB0aGUgY2hl Y2sgaW4gbHZtMiBpcyBlbm91Z2guIMKgQXJlIHRoZXJlIGFueSBvdGhlciB0b29scyB0aGF0IG1h eQ0KYmUgdXNlZCB0byBjb25maWd1cmUgc3RyaXBlIHNpemU/IMKgQ2FuIHdlIHRydXN0IHVzZXJz cGFjZSBvbiB0aGlzPw0KDQpUaGFua3MsDQotVG9zaGkKX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX18KTGludXgtbnZkaW1tIG1haWxpbmcgbGlzdApMaW51eC1u dmRpbW1AbGlzdHMuMDEub3JnCmh0dHBzOi8vbGlzdHMuMDEub3JnL21haWxtYW4vbGlzdGluZm8v bGludXgtbnZkaW1tCg== 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; 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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