From: Jens Axboe <axboe@fb.com>
To: Dan Williams <dan.j.williams@intel.com>, linux-block@vger.kernel.org
Cc: linux-nvdimm@lists.01.org, Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Jeff Moyer <jmoyer@redhat.com>, Jan Kara <jack@suse.com>,
linux-fsdevel@vger.kernel.org,
Matthew Wilcox <willy@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH 2/2] block: use DAX for partition table reads
Date: Fri, 29 Jan 2016 10:46:09 -0700 [thread overview]
Message-ID: <56ABA561.9070606@fb.com> (raw)
In-Reply-To: <20160129151846.18752.48460.stgit@dwillia2-desk3.amr.corp.intel.com>
On 01/29/2016 08:18 AM, Dan Williams wrote:
> +unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
> +{
> struct page *page;
>
> - page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
> - NULL);
> + /* don't populate page cache for dax capable devices */
> + if (IS_DAX(bdev->bd_inode))
> + page = read_dax_sector(bdev, n);
> + else
> + page = read_pagecache_sector(bdev, n);
> +
Fall back to non-dax, if dax fails?
> +struct page *read_dax_sector(struct block_device *bdev, sector_t n)
> +{
> + struct page *page = __page_cache_alloc(GFP_KERNEL | __GFP_COLD);
Why isn't that just alloc_pages()?
--
Jens Axboe
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@fb.com>
To: Dan Williams <dan.j.williams@intel.com>, <linux-block@vger.kernel.org>
Cc: <linux-nvdimm@ml01.01.org>, Dave Chinner <david@fromorbit.com>,
<linux-kernel@vger.kernel.org>, Christoph Hellwig <hch@lst.de>,
Jeff Moyer <jmoyer@redhat.com>, Jan Kara <jack@suse.com>,
<linux-fsdevel@vger.kernel.org>,
Matthew Wilcox <willy@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH 2/2] block: use DAX for partition table reads
Date: Fri, 29 Jan 2016 10:46:09 -0700 [thread overview]
Message-ID: <56ABA561.9070606@fb.com> (raw)
In-Reply-To: <20160129151846.18752.48460.stgit@dwillia2-desk3.amr.corp.intel.com>
On 01/29/2016 08:18 AM, Dan Williams wrote:
> +unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
> +{
> struct page *page;
>
> - page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
> - NULL);
> + /* don't populate page cache for dax capable devices */
> + if (IS_DAX(bdev->bd_inode))
> + page = read_dax_sector(bdev, n);
> + else
> + page = read_pagecache_sector(bdev, n);
> +
Fall back to non-dax, if dax fails?
> +struct page *read_dax_sector(struct block_device *bdev, sector_t n)
> +{
> + struct page *page = __page_cache_alloc(GFP_KERNEL | __GFP_COLD);
Why isn't that just alloc_pages()?
--
Jens Axboe
WARNING: multiple messages have this Message-ID (diff)
From: Jens Axboe <axboe@fb.com>
To: Dan Williams <dan.j.williams@intel.com>, <linux-block@vger.kernel.org>
Cc: <linux-nvdimm@lists.01.org>, Dave Chinner <david@fromorbit.com>,
<linux-kernel@vger.kernel.org>, Christoph Hellwig <hch@lst.de>,
Jeff Moyer <jmoyer@redhat.com>, Jan Kara <jack@suse.com>,
<linux-fsdevel@vger.kernel.org>,
Matthew Wilcox <willy@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH 2/2] block: use DAX for partition table reads
Date: Fri, 29 Jan 2016 10:46:09 -0700 [thread overview]
Message-ID: <56ABA561.9070606@fb.com> (raw)
In-Reply-To: <20160129151846.18752.48460.stgit@dwillia2-desk3.amr.corp.intel.com>
On 01/29/2016 08:18 AM, Dan Williams wrote:
> +unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
> +{
> struct page *page;
>
> - page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_CACHE_SHIFT-9)),
> - NULL);
> + /* don't populate page cache for dax capable devices */
> + if (IS_DAX(bdev->bd_inode))
> + page = read_dax_sector(bdev, n);
> + else
> + page = read_pagecache_sector(bdev, n);
> +
Fall back to non-dax, if dax fails?
> +struct page *read_dax_sector(struct block_device *bdev, sector_t n)
> +{
> + struct page *page = __page_cache_alloc(GFP_KERNEL | __GFP_COLD);
Why isn't that just alloc_pages()?
--
Jens Axboe
next prev parent reply other threads:[~2016-01-29 17:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-29 15:18 [PATCH 0/2] block: fix raw block device dax support Dan Williams
2016-01-29 15:18 ` Dan Williams
2016-01-29 15:18 ` [PATCH 1/2] block: revert runtime dax control of the raw block device Dan Williams
2016-01-29 15:18 ` Dan Williams
2016-01-29 17:54 ` Ross Zwisler
2016-01-29 17:54 ` Ross Zwisler
2016-01-29 15:18 ` [PATCH 2/2] block: use DAX for partition table reads Dan Williams
2016-01-29 15:18 ` Dan Williams
2016-01-29 17:46 ` Jens Axboe [this message]
2016-01-29 17:46 ` Jens Axboe
2016-01-29 17:46 ` Jens Axboe
2016-01-29 17:54 ` Dan Williams
2016-01-29 17:54 ` Dan Williams
2016-01-29 19:24 ` Ross Zwisler
2016-01-29 19:24 ` Ross Zwisler
2016-01-29 22:45 ` Matthew Wilcox
2016-01-29 22:45 ` Matthew Wilcox
2016-01-30 0:33 ` [PATCH v2] " Dan Williams
2016-01-30 0:33 ` Dan Williams
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