bitmap: bitmap_equal memcmp optimization

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The bitmap_equal function has optimized code for small bitmaps with less
than BITS_PER_LONG bits. For larger bitmaps the out-of-line function
__bitmap_equal is called.

For a constant number of bits divisible by BITS_PER_LONG the memcmp
function can be used. For s390 gcc knows how to optimize this function,
memcmp calls with up to 256 bytes / 2048 bits are translated into a
single instruction.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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Martin Schwidefsky 2016-05-25 09:32:20 +02:00

parent a9809407f6

commit 7dd968163f

1 changed files with 4 additions and 0 deletions

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include/linux/bitmap.h

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