From: Johannes Thumshirn <jthumshirn@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@lists.01.org,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
Hannes Reinecke <hare@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
hch@lst.de
Subject: Re: [PATCH v3 3/5] /dev/dax, core: file operations and dax-mmap
Date: Fri, 20 May 2016 09:58:33 +0200 [thread overview]
Message-ID: <20160520075833.GF4413@c203.arch.suse.de> (raw)
In-Reply-To: <146360498206.37439.343951904240579439.stgit@dwillia2-desk3.amr.corp.intel.com>
On Wed, May 18, 2016 at 01:56:22PM -0700, Dan Williams wrote:
> The "Device DAX" core enables dax mappings of performance / feature
> differentiated memory. An open mapping or file handle keeps the backing
> struct device live, but new mappings are only possible while the device
> is enabled. Faults are handled under rcu_read_lock to synchronize
> with the enabled state of the device.
>
> Similar to the filesystem-dax case the backing memory may optionally
> have struct page entries. However, unlike fs-dax there is no support
> for private mappings, or mappings that are not backed by media (see
> use of zero-page in fs-dax).
>
> Mappings are always guaranteed to match the alignment of the dax_region.
> If the dax_region is configured to have a 2MB alignment, all mappings
> are guaranteed to be backed by a pmd entry. Contrast this determinism
> with the fs-dax case where pmd mappings are opportunistic. If userspace
> attempts to force a misaligned mapping, the driver will fail the mmap
> attempt. See dax_dev_check_vma() for other scenarios that are rejected,
> like MAP_PRIVATE mappings.
>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
OK from my side,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
--
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
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Linux-nvdimm mailing list
Linux-nvdimm@lists.01.org
https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Johannes Thumshirn <jthumshirn@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@lists.01.org,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, hch@lst.de,
linux-block@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH v3 3/5] /dev/dax, core: file operations and dax-mmap
Date: Fri, 20 May 2016 09:58:33 +0200 [thread overview]
Message-ID: <20160520075833.GF4413@c203.arch.suse.de> (raw)
In-Reply-To: <146360498206.37439.343951904240579439.stgit@dwillia2-desk3.amr.corp.intel.com>
On Wed, May 18, 2016 at 01:56:22PM -0700, Dan Williams wrote:
> The "Device DAX" core enables dax mappings of performance / feature
> differentiated memory. An open mapping or file handle keeps the backing
> struct device live, but new mappings are only possible while the device
> is enabled. Faults are handled under rcu_read_lock to synchronize
> with the enabled state of the device.
>
> Similar to the filesystem-dax case the backing memory may optionally
> have struct page entries. However, unlike fs-dax there is no support
> for private mappings, or mappings that are not backed by media (see
> use of zero-page in fs-dax).
>
> Mappings are always guaranteed to match the alignment of the dax_region.
> If the dax_region is configured to have a 2MB alignment, all mappings
> are guaranteed to be backed by a pmd entry. Contrast this determinism
> with the fs-dax case where pmd mappings are opportunistic. If userspace
> attempts to force a misaligned mapping, the driver will fail the mmap
> attempt. See dax_dev_check_vma() for other scenarios that are rejected,
> like MAP_PRIVATE mappings.
>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
OK from my side,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
--
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
WARNING: multiple messages have this Message-ID (diff)
From: Johannes Thumshirn <jthumshirn@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@ml01.01.org,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-kernel@vger.kernel.org, hch@lst.de,
linux-block@vger.kernel.org, Hannes Reinecke <hare@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: [PATCH v3 3/5] /dev/dax, core: file operations and dax-mmap
Date: Fri, 20 May 2016 09:58:33 +0200 [thread overview]
Message-ID: <20160520075833.GF4413@c203.arch.suse.de> (raw)
In-Reply-To: <146360498206.37439.343951904240579439.stgit@dwillia2-desk3.amr.corp.intel.com>
On Wed, May 18, 2016 at 01:56:22PM -0700, Dan Williams wrote:
> The "Device DAX" core enables dax mappings of performance / feature
> differentiated memory. An open mapping or file handle keeps the backing
> struct device live, but new mappings are only possible while the device
> is enabled. Faults are handled under rcu_read_lock to synchronize
> with the enabled state of the device.
>
> Similar to the filesystem-dax case the backing memory may optionally
> have struct page entries. However, unlike fs-dax there is no support
> for private mappings, or mappings that are not backed by media (see
> use of zero-page in fs-dax).
>
> Mappings are always guaranteed to match the alignment of the dax_region.
> If the dax_region is configured to have a 2MB alignment, all mappings
> are guaranteed to be backed by a pmd entry. Contrast this determinism
> with the fs-dax case where pmd mappings are opportunistic. If userspace
> attempts to force a misaligned mapping, the driver will fail the mmap
> attempt. See dax_dev_check_vma() for other scenarios that are rejected,
> like MAP_PRIVATE mappings.
>
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Jeff Moyer <jmoyer@redhat.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
> Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
OK from my side,
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
--
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
next prev parent reply other threads:[~2016-05-20 7:58 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-18 20:56 [PATCH v3 0/5] "Device DAX" for persistent memory Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` [PATCH v3 1/5] libnvdimm: stop requiring a driver ->remove() method Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-20 7:29 ` Johannes Thumshirn
2016-05-20 7:29 ` Johannes Thumshirn
2016-05-20 7:29 ` Johannes Thumshirn
2016-05-18 20:56 ` [PATCH v3 2/5] /dev/dax, pmem: direct access to persistent memory Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-20 8:01 ` Johannes Thumshirn
2016-05-20 8:01 ` Johannes Thumshirn
2016-05-20 8:01 ` Johannes Thumshirn
2016-05-20 9:41 ` Xiong Zhou
2016-05-18 20:56 ` [PATCH v3 3/5] /dev/dax, core: file operations and dax-mmap Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-20 7:58 ` Johannes Thumshirn [this message]
2016-05-20 7:58 ` Johannes Thumshirn
2016-05-20 7:58 ` Johannes Thumshirn
2016-05-18 20:56 ` [PATCH v3 4/5] Revert "block: enable dax for raw block devices" Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` [PATCH v3 5/5] libnvdimm: release ida resources Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-18 20:56 ` Dan Williams
2016-05-20 7:30 ` Johannes Thumshirn
2016-05-20 7:30 ` Johannes Thumshirn
2016-05-20 7:30 ` Johannes Thumshirn
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