From: Theodore Ts'o <tytso@mit.edu>
To: Lukas Czerner <lczerner@redhat.com>
Cc: linux-ext4@vger.kernel.org, darrick.wong@oracle.com
Subject: Re: [PATCH v2] ext4: Transfer initialized block to right neighbor if possible
Date: Mon, 1 Apr 2013 11:12:16 -0400 [thread overview]
Message-ID: <20130401151216.GC4731@thunk.org> (raw)
In-Reply-To: <1363791235-18707-1-git-send-email-lczerner@redhat.com>
On Wed, Mar 20, 2013 at 03:53:55PM +0100, Lukas Czerner wrote:
> Currently when converting extent to initialized we attempt to transfer
> initialized block to the left neighbour if possible when certain criteria
> are met. However we do not attempt to do the same for the right
> neighbor.
>
> This commit adds the possibility to transfer initialized block to the
> right neighbour if:
>
> 1. We're not converting the whole extent
> 2. Both extents are stored in the same extent tree node
> 3. Right neighbor is initialized
> 4. Right neighbor is logically abutting the current one
> 5. Right neighbor is physically abutting the current one
> 6. Right neighbor would not overflow the length limit
>
> This is basically the same logic as with transferring to the left. This
> will gain us some performance benefits since it is faster than inserting
> extent and then merging it.
>
> It would also prevent some situation in delalloc patch when we might run
> out of metadata reservation. This is due to the fact that we would
> attempt to split the extent first (possibly allocating new metadata
> block) even though we did not counted for that because it can (and will)
> be merged again. This commit fix that scenario, because we no longer
> need to split the extent in such case.
>
> Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Thanks, applied to the dev branch for testing
- Ted
prev parent reply other threads:[~2013-04-01 15:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-19 13:13 [PATCH] ext4: Transfer initialized block to right neighbor if possible Lukas Czerner
2013-03-19 18:48 ` Darrick J. Wong
2013-03-20 14:53 ` [PATCH v2] " Lukas Czerner
2013-04-01 15:12 ` Theodore Ts'o [this message]
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