From: Christoph Hellwig <hch@infradead.org>
To: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>, xfs@oss.sgi.com
Subject: Re: [PATCH 23/28] xfs: byteswap constants instead of variables
Date: Thu, 7 Jul 2011 12:28:24 -0400 [thread overview]
Message-ID: <20110707162824.GA7830@infradead.org> (raw)
In-Reply-To: <1310055860.1980.23.camel@doink>
On Thu, Jul 07, 2011 at 11:24:20AM -0500, Alex Elder wrote:
> On Thu, 2011-07-07 at 07:05 -0400, Christoph Hellwig wrote:
> > Micro-optimize various comparisms by always byteswapping the constant
> > instead of the variable, which allows to do the swap at compile instead
> > of runtime.
> >
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Ha!!! You missed one! File "fs/xfs/xfs_dir2_node.c"
> lines 412-413 (after applying this patch):
>
> ASSERT(be32_to_cpu(free->hdr.magic) == XFS_DIR2_FREE_MAGIC);
I left a few where we are doing the same byteswap a little later again,
but this one doesn't seem to fall into the category. Oh, I see why now:
my grep only found the _MAGIC and the byteswap on the same line.
> Also, xfs_magics[] in "fs/xfs/xfs_btree.c" could be
> initialized with the pre-byte-swapped versions of
> the constants (and the array should be given static
> scope as well).
Yeah, but let's keep this patch simple for now.
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next prev parent reply other threads:[~2011-07-07 16:28 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-07 11:05 [PATCH 00/28] patch queue for Linux 3.1, V3 Christoph Hellwig
2011-07-07 11:05 ` [PATCH 01/28] xfs: PF_FSTRANS should never be set in ->writepage Christoph Hellwig
2011-07-07 11:05 ` [PATCH 02/28] xfs: re-enable non-blocking behaviour in xfs_map_blocks Christoph Hellwig
2011-07-08 10:19 ` Dave Chinner
2011-07-07 11:05 ` [PATCH 03/28] xfs: work around bogus gcc warning in xfs_allocbt_init_cursor Christoph Hellwig
2011-07-07 11:05 ` [PATCH 04/28] xfs: split xfs_setattr Christoph Hellwig
2011-07-07 11:05 ` [PATCH 06/28] xfs: kill xfs_itruncate_start Christoph Hellwig
2011-07-07 11:05 ` [PATCH 07/28] xfs: split xfs_itruncate_finish Christoph Hellwig
2011-07-07 11:05 ` [PATCH 08/28] xfs: improve sync behaviour in the face of aggressive dirtying Christoph Hellwig
2011-07-07 11:05 ` [PATCH 09/28] xfs: fix filesystsem freeze race in xfs_trans_alloc Christoph Hellwig
2011-07-07 11:05 ` [PATCH 10/28] xfs: remove i_transp Christoph Hellwig
2011-07-07 11:05 ` [PATCH 11/28] xfs: kill the unused struct xfs_sync_work Christoph Hellwig
2011-07-08 10:20 ` Dave Chinner
2011-07-07 11:05 ` [PATCH 12/28] xfs: factor out xfs_dir2_leaf_find_entry Christoph Hellwig
2011-07-07 11:05 ` [PATCH 13/28] xfs: cleanup shortform directory inode number handling Christoph Hellwig
2011-07-07 11:05 ` [PATCH 14/28] xfs: kill struct xfs_dir2_sf Christoph Hellwig
2011-07-07 11:05 ` [PATCH 15/28] xfs: cleanup the definition of struct xfs_dir2_sf_entry Christoph Hellwig
2011-07-07 11:05 ` [PATCH 16/28] xfs: avoid usage of struct xfs_dir2_block Christoph Hellwig
2011-07-07 11:05 ` [PATCH 17/28] xfs: kill " Christoph Hellwig
2011-07-08 10:20 ` Dave Chinner
2011-07-07 11:05 ` [PATCH 18/28] xfs: avoid usage of struct xfs_dir2_data Christoph Hellwig
2011-07-07 11:05 ` [PATCH 19/28] xfs: kill " Christoph Hellwig
2011-07-07 11:05 ` [PATCH 20/28] xfs: cleanup the definition of struct xfs_dir2_data_entry Christoph Hellwig
2011-07-07 11:05 ` [PATCH 21/28] xfs: cleanup struct xfs_dir2_leaf Christoph Hellwig
2011-07-08 10:21 ` Dave Chinner
2011-07-07 11:05 ` [PATCH 22/28] xfs: use generic get_unaligned_beXX helpers Christoph Hellwig
2011-07-08 10:22 ` Dave Chinner
2011-07-07 11:05 ` [PATCH 23/28] xfs: byteswap constants instead of variables Christoph Hellwig
2011-07-07 16:24 ` Alex Elder
2011-07-07 16:28 ` Christoph Hellwig [this message]
2011-07-08 10:26 ` Dave Chinner
2011-07-07 11:05 ` [PATCH 24/28] xfs: remove the unused xfs_bufhash structure Christoph Hellwig
2011-07-07 11:06 ` [PATCH 25/28] xfs: clean up buffer locking helpers Christoph Hellwig
2011-07-07 11:06 ` [PATCH 26/28] xfs: return the buffer locked from xfs_buf_get_uncached Christoph Hellwig
2011-07-07 11:06 ` [PATCH 27/28] xfs: cleanup I/O-related buffer flags Christoph Hellwig
2011-07-07 11:06 ` [PATCH 28/28] xfs: avoid a few disk cache flushes Christoph Hellwig
2011-07-08 10:18 ` [PATCH 00/28] patch queue for Linux 3.1, V3 Dave Chinner
2011-07-08 12:28 ` Christoph Hellwig
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