xfs: pack xfs_buf structure more tightly

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pahole reports the struct xfs_buf has quite a few holes in it, so
packing the structure better will reduce the size of it by 16 bytes.
Also, move all the fields used in cache lookups into the first
cacheline.

Before on x86_64:

        /* size: 320, cachelines: 5 */
	/* sum members: 298, holes: 6, sum holes: 22 */

After on x86_64:

        /* size: 304, cachelines: 5 */
	/* padding: 6 */
	/* last cacheline: 48 bytes */

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>

...

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Dave Chinner 2010-09-24 19:59:15 +10:00 • committed by Alex Elder

parent 74f75a0cb7

commit 50f59e8eed

1 changed files with 19 additions and 11 deletions

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fs/xfs/linux-2.6/xfs_buf.h

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