From: Jan Kara <jack@suse.cz>
To: Dave Chinner <david@fromorbit.com>
Cc: jack@suse.cz, linux-nvdimm@lists.01.org,
Brian Foster <bfoster@redhat.com>,
xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org,
ross.zwisler@linux.intel.com, dan.j.williams@intel.com
Subject: Re: [PATCH 3/6] xfs: Don't use unwritten extents for DAX
Date: Tue, 3 Nov 2015 10:16:05 +0100 [thread overview]
Message-ID: <20151103091605.GA4063@quack.suse.cz> (raw)
In-Reply-To: <20151102214424.GJ10656@dastard>
On Tue 03-11-15 08:44:24, Dave Chinner wrote:
> Realistically, dax_clear_blocks() should probably be implemented at
> the pmem driver layer through blkdev_issue_zeroout() because all it
> does is directly map the sector/len to pfn via bdev_direct_access()
> and then zero it - it's a sector based, block device operation. We
> don't actually need a special case path for DAX here. Optimisation
> of this operation has little to do with the filesystem.
Yep. This is actually what I did in ext4 - the block zeroing is using the
ext4 block zeroout path which ends up calling blkdev_issue_zeroout(). I
didn't want to special-case DAX and figured out that if we want
performance, we should implement blkdev_issue_zeroout() efficiently for
pmem. After all ext4 uses blkdev_issue_zeroout() in other extent conversion
cases where zeroing out is needed.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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prev parent reply other threads:[~2015-11-03 9:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1445225238-30413-1-git-send-email-david@fromorbit.com>
[not found] ` <1445225238-30413-4-git-send-email-david@fromorbit.com>
[not found] ` <20151029142950.GE11663@bfoster.bfoster>
[not found] ` <20151029233756.GS19199@dastard>
[not found] ` <20151030123657.GC54905@bfoster.bfoster>
[not found] ` <20151102011433.GW19199@dastard>
[not found] ` <20151102141509.GA29346@bfoster.bfoster>
2015-11-02 21:44 ` [PATCH 3/6] xfs: Don't use unwritten extents for DAX Dave Chinner
2015-11-03 3:53 ` Dan Williams
2015-11-03 5:04 ` Dave Chinner
2015-11-04 0:50 ` Ross Zwisler
2015-11-04 1:02 ` Dan Williams
2015-11-04 4:46 ` Ross Zwisler
2015-11-04 9:06 ` Jan Kara
2015-11-04 15:35 ` Ross Zwisler
2015-11-04 17:21 ` Jan Kara
2015-11-03 9:16 ` Jan Kara [this message]
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