dm thin: optimize power of two block size

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dm-thin will be most likely used with a block size that is a power of
two. So it should be optimized for this case.

This patch changes division and modulo operations to shifts and bit
masks if block size is a power of two.

A test that bi_sector is divisible by a block size is removed from
io_overlaps_block. Device mapper never sends bios that span a block
boundary. Consequently, if we tested that bi_size is equivalent to block
size, bi_sector must already be on a block boundary.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

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This commit is contained in:

Mikulas Patocka 2012-07-27 15:08:03 +01:00 • committed by Alasdair G Kergon

parent 4929630901

commit f9a8e0cd26

1 changed files with 16 additions and 7 deletions

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drivers/md/dm-thin.c

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