From: Dave Chinner <david@fromorbit.com>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 4/4] xfs: speed up write operations by using non-overlapped lookups when possible
Date: Wed, 27 Apr 2022 14:22:00 +1000 [thread overview]
Message-ID: <20220427042200.GF1098723@dread.disaster.area> (raw)
In-Reply-To: <165102070826.3922526.7040761074869734523.stgit@magnolia>
On Tue, Apr 26, 2022 at 05:51:48PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
>
> Reverse mapping on a reflink-capable filesystem has some pretty high
> overhead when performing file operations. This is because the rmap
> records for logically and physically adjacent extents might not be
> adjacent in the rmap index due to data block sharing. As a result, we
> use expensive overlapped-interval btree search, which walks every record
> that overlaps with the supplied key in the hopes of finding the record.
>
> However, profiling data shows that when the index contains a record that
> is an exact match for a query key, the non-overlapped btree search
> function can find the record much faster than the overlapped version.
> Try the non-overlapped lookup first when we're trying to find the left
> neighbor rmap record for a given file mapping, which makes unwritten
> extent conversion and remap operations run faster if data block sharing
> is minimal in this part of the filesystem.
>
> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Looks good now.
Reviewed-by: Dave Chinner <dchinner@redhat.com>
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2022-04-27 4:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-27 0:51 [PATCHSET v2 0/4] xfs: fix rmap inefficiencies Darrick J. Wong
2022-04-27 0:51 ` [PATCH 1/4] xfs: capture buffer ops in the xfs_buf tracepoints Darrick J. Wong
2022-04-27 0:51 ` [PATCH 2/4] xfs: simplify xfs_rmap_lookup_le call sites Darrick J. Wong
2022-04-27 0:51 ` [PATCH 3/4] xfs: speed up rmap lookups by using non-overlapped lookups when possible Darrick J. Wong
2022-04-27 4:19 ` Dave Chinner
2022-04-28 12:44 ` Christoph Hellwig
2022-04-27 0:51 ` [PATCH 4/4] xfs: speed up write operations " Darrick J. Wong
2022-04-27 4:22 ` Dave Chinner [this message]
2022-04-28 12:45 ` Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2022-04-14 22:53 [PATCHSET 0/4] xfs: fix rmap inefficiencies Darrick J. Wong
2022-04-14 22:54 ` [PATCH 4/4] xfs: speed up write operations by using non-overlapped lookups when possible Darrick J. Wong
2022-04-22 21:46 ` Dave Chinner
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