From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH 4/5] xfs: speed up directory bestfree block scanning
Date: Thu, 29 Aug 2019 19:31:17 +1000 [thread overview]
Message-ID: <20190829093117.GS1119@dread.disaster.area> (raw)
In-Reply-To: <20190829082501.GA18614@infradead.org>
On Thu, Aug 29, 2019 at 01:25:01AM -0700, Christoph Hellwig wrote:
> Actually, another comment:
>
> > + /* Scan the free entry array for a large enough free space. */
> > + do {
> > + if (be16_to_cpu(bests[findex]) != NULLDATAOFF &&
>
> This could be changed to:
>
> if (bests[findex] != cpu_to_be16(NULLDATAOFF) &&
>
> which might lead to slightly better code generation.
I don't think it will make any difference because the very next
comparison in the if() statement needs the cpu order bests[findex]
value because its a >= check. Hence we have to calculate it anyway,
and the compiler should be smart enough to only evaluate it once...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2019-08-29 9:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-29 6:30 [PATCH V2 0/5] xfs: speed up large directory modifications Dave Chinner
2019-08-29 6:30 ` [PATCH 1/5] xfs: move xfs_dir2_addname() Dave Chinner
2019-08-29 7:59 ` Christoph Hellwig
2019-08-29 6:30 ` [PATCH 2/5] xfs: factor data block addition from xfs_dir2_node_addname_int() Dave Chinner
2019-08-29 8:05 ` Christoph Hellwig
2019-08-29 8:34 ` Dave Chinner
2019-08-29 6:30 ` [PATCH 3/5] xfs: factor free block index lookup " Dave Chinner
2019-08-29 8:10 ` Christoph Hellwig
2019-08-29 8:35 ` Dave Chinner
2019-08-29 6:30 ` [PATCH 4/5] xfs: speed up directory bestfree block scanning Dave Chinner
2019-08-29 8:18 ` Christoph Hellwig
2019-08-29 8:45 ` Dave Chinner
2019-08-29 8:47 ` Christoph Hellwig
2019-08-29 8:55 ` Dave Chinner
2019-08-29 8:25 ` Christoph Hellwig
2019-08-29 9:31 ` Dave Chinner [this message]
2019-08-29 9:33 ` Christoph Hellwig
2019-08-29 6:30 ` [PATCH 5/5] xfs: reverse search directory freespace indexes Dave Chinner
2019-08-29 8:23 ` Christoph Hellwig
2019-08-29 9:14 ` Dave Chinner
-- strict thread matches above, loose matches on Subject: below --
2019-08-29 10:47 [PATCH v3 0/5] xfs: speed up large directory modifications Dave Chinner
2019-08-29 10:47 ` [PATCH 4/5] xfs: speed up directory bestfree block scanning Dave Chinner
2019-08-29 21:18 ` Darrick J. Wong
2019-08-30 5:24 ` Christoph Hellwig
2018-10-24 22:57 [PATCH 0/5] xfs: speed up large directory modifications Dave Chinner
2018-10-24 22:57 ` [PATCH 4/5] xfs: speed up directory bestfree block scanning Dave Chinner
2018-10-26 10:24 ` Christoph Hellwig
2018-10-26 10:58 ` Dave Chinner
2018-10-26 11:56 ` Christoph Hellwig
2018-10-26 12:12 ` Christoph Hellwig
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