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From: "Kani, Toshimitsu" <toshi.kani@hpe.com>
To: "kirill@shutemov.name" <kirill@shutemov.name>
Cc: "tytso@mit.edu" <tytso@mit.edu>,
	"mawilcox@microsoft.com" <mawilcox@microsoft.com>,
	"david@fromorbit.com" <david@fromorbit.com>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
	"hughd@google.com" <hughd@google.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"adilger.kernel@dilger.ca" <adilger.kernel@dilger.ca>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"jack@suse.cz" <jack@suse.cz>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	"mike.kravetz@oracle.com" <mike.kravetz@oracle.com>
Subject: Re: [PATCH v4 RESEND 0/2] Align mmap address for DAX pmd mappings
Date: Mon, 29 Aug 2016 21:32:32 +0000	[thread overview]
Message-ID: <1472506310.1532.47.camel@hpe.com> (raw)
In-Reply-To: <20160829204842.GA27286@node.shutemov.name>

On Mon, 2016-08-29 at 23:48 +0300, Kirill A. Shutemov wrote:
> On Mon, Aug 29, 2016 at 01:11:19PM -0600, Toshi Kani wrote:
> > 
> > When CONFIG_FS_DAX_PMD is set, DAX supports mmap() using pmd page
> > size.  This feature relies on both mmap virtual address and FS
> > block (i.e. physical address) to be aligned by the pmd page size.
> > Users can use mkfs options to specify FS to align block
> > allocations. However, aligning mmap address requires code changes
> > to existing applications for providing a pmd-aligned address to
> > mmap().
> > 
> > For instance, fio with "ioengine=mmap" performs I/Os with mmap()
> > [1]. It calls mmap() with a NULL address, which needs to be changed
> > to provide a pmd-aligned address for testing with DAX pmd mappings.
> > Changing all applications that call mmap() with NULL is
> > undesirable.
> > 
> > This patch-set extends filesystems to align an mmap address for
> > a DAX file so that unmodified applications can use DAX pmd
> > mappings.
> 
> +Hugh
> 
> Can we get it used for shmem/tmpfs too?
> I don't think we should duplicate essentially the same functionality
> in multiple places.

Here is my brief analysis when I had looked at the Hugh's patch last
time (before shmem_get_unmapped_area() was accepted).
https://patchwork.kernel.org/patch/8916741/

Besides some differences in the logic, ex. shmem_get_unmapped_area()
always calls current->mm->get_unmapped_area twice, yes, they basically
provide the same functionality.

I think one issue is that shmem_get_unmapped_area() checks with its
static flag 'shmem_huge', and additinally deals with SHMEM_HUGE_DENY
and SHMEM_HUGE_FORCE cases.  It also handles non-file case for
!SHMEM_HUGE_FORCE.

Thanks,
-Toshi



_______________________________________________
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: "Kani, Toshimitsu" <toshi.kani@hpe.com>
To: "kirill@shutemov.name" <kirill@shutemov.name>
Cc: "hughd@google.com" <hughd@google.com>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"adilger.kernel@dilger.ca" <adilger.kernel@dilger.ca>,
	"mike.kravetz@oracle.com" <mike.kravetz@oracle.com>,
	"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
	"mawilcox@microsoft.com" <mawilcox@microsoft.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@lists.01.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>,
	"tytso@mit.edu" <tytso@mit.edu>,
	"david@fromorbit.com" <david@fromorbit.com>,
	"jack@suse.cz" <jack@suse.cz>
Subject: Re: [PATCH v4 RESEND 0/2] Align mmap address for DAX pmd mappings
Date: Mon, 29 Aug 2016 21:32:32 +0000	[thread overview]
Message-ID: <1472506310.1532.47.camel@hpe.com> (raw)
In-Reply-To: <20160829204842.GA27286@node.shutemov.name>

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1869 bytes --]

On Mon, 2016-08-29 at 23:48 +0300, Kirill A. Shutemov wrote:
> On Mon, Aug 29, 2016 at 01:11:19PM -0600, Toshi Kani wrote:
> > 
> > When CONFIG_FS_DAX_PMD is set, DAX supports mmap() using pmd page
> > size.  This feature relies on both mmap virtual address and FS
> > block (i.e. physical address) to be aligned by the pmd page size.
> > Users can use mkfs options to specify FS to align block
> > allocations. However, aligning mmap address requires code changes
> > to existing applications for providing a pmd-aligned address to
> > mmap().
> > 
> > For instance, fio with "ioengine=mmap" performs I/Os with mmap()
> > [1]. It calls mmap() with a NULL address, which needs to be changed
> > to provide a pmd-aligned address for testing with DAX pmd mappings.
> > Changing all applications that call mmap() with NULL is
> > undesirable.
> > 
> > This patch-set extends filesystems to align an mmap address for
> > a DAX file so that unmodified applications can use DAX pmd
> > mappings.
> 
> +Hugh
> 
> Can we get it used for shmem/tmpfs too?
> I don't think we should duplicate essentially the same functionality
> in multiple places.

Here is my brief analysis when I had looked at the Hugh's patch last
time (before shmem_get_unmapped_area() was accepted).
https://patchwork.kernel.org/patch/8916741/

Besides some differences in the logic, ex. shmem_get_unmapped_area()
always calls current->mm->get_unmapped_area twice, yes, they basically
provide the same functionality.

I think one issue is that shmem_get_unmapped_area() checks with its
static flag 'shmem_huge', and additinally deals with SHMEM_HUGE_DENY
and SHMEM_HUGE_FORCE cases.  It also handles non-file case for
!SHMEM_HUGE_FORCE.

Thanks,
-Toshi



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WARNING: multiple messages have this Message-ID (diff)
From: "Kani, Toshimitsu" <toshi.kani@hpe.com>
To: "kirill@shutemov.name" <kirill@shutemov.name>
Cc: "hughd@google.com" <hughd@google.com>,
	"kirill.shutemov@linux.intel.com"
	<kirill.shutemov@linux.intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"adilger.kernel@dilger.ca" <adilger.kernel@dilger.ca>,
	"mike.kravetz@oracle.com" <mike.kravetz@oracle.com>,
	"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
	"mawilcox@microsoft.com" <mawilcox@microsoft.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"ross.zwisler@linux.intel.com" <ross.zwisler@linux.intel.com>,
	"tytso@mit.edu" <tytso@mit.edu>,
	"david@fromorbit.com" <david@fromorbit.com>,
	"jack@suse.cz" <jack@suse.cz>
Subject: Re: [PATCH v4 RESEND 0/2] Align mmap address for DAX pmd mappings
Date: Mon, 29 Aug 2016 21:32:32 +0000	[thread overview]
Message-ID: <1472506310.1532.47.camel@hpe.com> (raw)
In-Reply-To: <20160829204842.GA27286@node.shutemov.name>

On Mon, 2016-08-29 at 23:48 +0300, Kirill A. Shutemov wrote:
> On Mon, Aug 29, 2016 at 01:11:19PM -0600, Toshi Kani wrote:
> > 
> > When CONFIG_FS_DAX_PMD is set, DAX supports mmap() using pmd page
> > size.  This feature relies on both mmap virtual address and FS
> > block (i.e. physical address) to be aligned by the pmd page size.
> > Users can use mkfs options to specify FS to align block
> > allocations. However, aligning mmap address requires code changes
> > to existing applications for providing a pmd-aligned address to
> > mmap().
> > 
> > For instance, fio with "ioengine=mmap" performs I/Os with mmap()
> > [1]. It calls mmap() with a NULL address, which needs to be changed
> > to provide a pmd-aligned address for testing with DAX pmd mappings.
> > Changing all applications that call mmap() with NULL is
> > undesirable.
> > 
> > This patch-set extends filesystems to align an mmap address for
> > a DAX file so that unmodified applications can use DAX pmd
> > mappings.
> 
> +Hugh
> 
> Can we get it used for shmem/tmpfs too?
> I don't think we should duplicate essentially the same functionality
> in multiple places.

Here is my brief analysis when I had looked at the Hugh's patch last
time (before shmem_get_unmapped_area() was accepted).
https://patchwork.kernel.org/patch/8916741/

Besides some differences in the logic, ex. shmem_get_unmapped_area()
always calls current->mm->get_unmapped_area twice, yes, they basically
provide the same functionality.

I think one issue is that shmem_get_unmapped_area() checks with its
static flag 'shmem_huge', and additinally deals with SHMEM_HUGE_DENY
and SHMEM_HUGE_FORCE cases.  It also handles non-file case for
!SHMEM_HUGE_FORCE.

Thanks,
-Toshi

  reply	other threads:[~2016-08-29 21:32 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-29 19:11 [PATCH v4 RESEND 0/2] Align mmap address for DAX pmd mappings Toshi Kani
2016-08-29 19:11 ` Toshi Kani
2016-08-29 19:11 ` Toshi Kani
2016-08-29 19:11 ` [PATCH v4 RESEND 1/2] thp, dax: add thp_get_unmapped_area for " Toshi Kani
2016-08-29 19:11   ` Toshi Kani
2016-08-29 19:11   ` Toshi Kani
2016-08-29 19:34   ` Dan Williams
2016-08-29 19:34     ` Dan Williams
2016-08-29 19:34     ` Dan Williams
2016-08-29 20:44     ` Kani, Toshimitsu
2016-08-29 20:44       ` Kani, Toshimitsu
2016-08-29 20:44       ` Kani, Toshimitsu
2016-08-29 20:54       ` Dan Williams
2016-08-29 20:54         ` Dan Williams
2016-08-29 20:54         ` Dan Williams
2016-08-29 19:11 ` [PATCH v4 RESEND 2/2] ext2/4, xfs: call thp_get_unmapped_area() " Toshi Kani
2016-08-29 19:11   ` Toshi Kani
2016-08-29 19:11   ` Toshi Kani
2016-08-29 20:48 ` [PATCH v4 RESEND 0/2] Align mmap address for DAX " Kirill A. Shutemov
2016-08-29 20:48   ` Kirill A. Shutemov
2016-08-29 20:48   ` Kirill A. Shutemov
2016-08-29 21:32   ` Kani, Toshimitsu [this message]
2016-08-29 21:32     ` Kani, Toshimitsu
2016-08-29 21:32     ` Kani, Toshimitsu
2016-08-29 22:00     ` Kani, Toshimitsu
2016-08-29 22:00       ` Kani, Toshimitsu
2016-08-29 22:00       ` Kani, Toshimitsu
2016-09-08 10:57       ` Kirill A. Shutemov
2016-09-08 10:57         ` Kirill A. Shutemov
2016-09-08 10:57         ` Kirill A. Shutemov
2016-09-08 13:49         ` Kani, Toshimitsu
2016-09-08 13:49           ` Kani, Toshimitsu
2016-09-08 13:49           ` Kani, Toshimitsu
2016-09-08 23:21           ` Kani, Toshimitsu
2016-09-08 23:21             ` Kani, Toshimitsu
2016-09-08 23:21             ` Kani, Toshimitsu
2016-09-09 12:36             ` Kirill A. Shutemov
2016-09-09 12:36               ` Kirill A. Shutemov
2016-09-09 12:36               ` Kirill A. Shutemov
2016-09-09 17:21               ` Kani, Toshimitsu
2016-09-09 17:21                 ` Kani, Toshimitsu
2016-09-09 17:21                 ` Kani, Toshimitsu
2016-09-09 18:37                 ` Kirill A. Shutemov
2016-09-09 18:37                   ` Kirill A. Shutemov
2016-09-09 18:37                   ` Kirill A. Shutemov
2016-09-09 18:37                   ` Kirill A. Shutemov

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