From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 76DF61A1DF7 for ; Fri, 20 May 2016 01:01:45 -0700 (PDT) Date: Fri, 20 May 2016 10:01:36 +0200 From: Johannes Thumshirn Subject: Re: [PATCH v3 2/5] /dev/dax, pmem: direct access to persistent memory Message-ID: <20160520080136.GG4413@c203.arch.suse.de> References: <146360496572.37439.6497663679891935585.stgit@dwillia2-desk3.amr.corp.intel.com> <146360497642.37439.12866290214925858506.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <146360497642.37439.12866290214925858506.stgit@dwillia2-desk3.amr.corp.intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dan Williams Cc: linux-nvdimm@lists.01.org, Dave Hansen , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, Andrew Morton , hch@lst.de List-ID: On Wed, May 18, 2016 at 01:56:16PM -0700, Dan Williams wrote: > Device DAX is the device-centric analogue of Filesystem DAX > (CONFIG_FS_DAX). It allows memory ranges to be allocated and mapped > without need of an intervening file system. Device DAX is strict, > precise and predictable. Specifically this interface: > = > 1/ Guarantees fault granularity with respect to a given page size (pte, > pmd, or pud) set at configuration time. > = > 2/ Enforces deterministic behavior by being strict about what fault > scenarios are supported. > = > For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE > support device-dax guarantees that a mapping always behaves/performs the > same once established. It is the "what you see is what you get" access > mechanism to differentiated memory vs filesystem DAX which has > filesystem specific implementation semantics. > = > Persistent memory is the first target, but the mechanism is also > targeted for exclusive allocations of performance differentiated memory > ranges. > = > This commit is limited to the base device driver infrastructure to > associate a dax device with pmem range. > = > Cc: Jeff Moyer > Cc: Christoph Hellwig > Cc: Andrew Morton > Cc: Dave Hansen > Cc: Ross Zwisler > Signed-off-by: Dan Williams Reviewed-by: Johannes Thumshirn -- = Johannes Thumshirn Storage jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N=FCrnberg GF: Felix Imend=F6rffer, Jane Smithard, Graham Norton HRB 21284 (AG N=FCrnberg) Key fingerprint =3D EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:51053 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755166AbcETIBj (ORCPT ); Fri, 20 May 2016 04:01:39 -0400 Date: Fri, 20 May 2016 10:01:36 +0200 From: Johannes Thumshirn To: Dan Williams Cc: linux-nvdimm@lists.01.org, Dave Hansen , linux-kernel@vger.kernel.org, hch@lst.de, linux-block@vger.kernel.org, Andrew Morton Subject: Re: [PATCH v3 2/5] /dev/dax, pmem: direct access to persistent memory Message-ID: <20160520080136.GG4413@c203.arch.suse.de> References: <146360496572.37439.6497663679891935585.stgit@dwillia2-desk3.amr.corp.intel.com> <146360497642.37439.12866290214925858506.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <146360497642.37439.12866290214925858506.stgit@dwillia2-desk3.amr.corp.intel.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Wed, May 18, 2016 at 01:56:16PM -0700, Dan Williams wrote: > Device DAX is the device-centric analogue of Filesystem DAX > (CONFIG_FS_DAX). It allows memory ranges to be allocated and mapped > without need of an intervening file system. Device DAX is strict, > precise and predictable. Specifically this interface: > > 1/ Guarantees fault granularity with respect to a given page size (pte, > pmd, or pud) set at configuration time. > > 2/ Enforces deterministic behavior by being strict about what fault > scenarios are supported. > > For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE > support device-dax guarantees that a mapping always behaves/performs the > same once established. It is the "what you see is what you get" access > mechanism to differentiated memory vs filesystem DAX which has > filesystem specific implementation semantics. > > Persistent memory is the first target, but the mechanism is also > targeted for exclusive allocations of performance differentiated memory > ranges. > > This commit is limited to the base device driver infrastructure to > associate a dax device with pmem range. > > Cc: Jeff Moyer > Cc: Christoph Hellwig > Cc: Andrew Morton > Cc: Dave Hansen > Cc: Ross Zwisler > Signed-off-by: Dan Williams Reviewed-by: Johannes Thumshirn -- Johannes Thumshirn Storage jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg GF: Felix Imend�rffer, Jane Smithard, Graham Norton HRB 21284 (AG N�rnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755769AbcETIBk (ORCPT ); Fri, 20 May 2016 04:01:40 -0400 Received: from mx2.suse.de ([195.135.220.15]:51053 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755166AbcETIBj (ORCPT ); Fri, 20 May 2016 04:01:39 -0400 Date: Fri, 20 May 2016 10:01:36 +0200 From: Johannes Thumshirn To: Dan Williams Cc: linux-nvdimm@ml01.01.org, Dave Hansen , linux-kernel@vger.kernel.org, hch@lst.de, linux-block@vger.kernel.org, Andrew Morton Subject: Re: [PATCH v3 2/5] /dev/dax, pmem: direct access to persistent memory Message-ID: <20160520080136.GG4413@c203.arch.suse.de> References: <146360496572.37439.6497663679891935585.stgit@dwillia2-desk3.amr.corp.intel.com> <146360497642.37439.12866290214925858506.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <146360497642.37439.12866290214925858506.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 18, 2016 at 01:56:16PM -0700, Dan Williams wrote: > Device DAX is the device-centric analogue of Filesystem DAX > (CONFIG_FS_DAX). It allows memory ranges to be allocated and mapped > without need of an intervening file system. Device DAX is strict, > precise and predictable. Specifically this interface: > > 1/ Guarantees fault granularity with respect to a given page size (pte, > pmd, or pud) set at configuration time. > > 2/ Enforces deterministic behavior by being strict about what fault > scenarios are supported. > > For example, by forcing MADV_DONTFORK semantics and omitting MAP_PRIVATE > support device-dax guarantees that a mapping always behaves/performs the > same once established. It is the "what you see is what you get" access > mechanism to differentiated memory vs filesystem DAX which has > filesystem specific implementation semantics. > > Persistent memory is the first target, but the mechanism is also > targeted for exclusive allocations of performance differentiated memory > ranges. > > This commit is limited to the base device driver infrastructure to > associate a dax device with pmem range. > > Cc: Jeff Moyer > Cc: Christoph Hellwig > Cc: Andrew Morton > Cc: Dave Hansen > Cc: Ross Zwisler > Signed-off-by: Dan Williams Reviewed-by: Johannes Thumshirn -- Johannes Thumshirn Storage jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850