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Commit ca1250bb authored by Yury Norov's avatar Yury Norov Committed by Linus Torvalds
Browse files

lib/bitmap.c: micro-optimization for __bitmap_complement() 

Use BITS_TO_LONGS() macro to avoid calculation of reminder (bits %
BITS_PER_LONG) On ARM64 it saves 5 instruction for function - 16 before
and 11 after.

Link: http://lkml.kernel.org/r/20180411145914.6011-1-ynorov@caviumnetworks.com


Signed-off-by: default avatarYury Norov <ynorov@caviumnetworks.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0455c747

lib/bitmap.c

+1 −4
Original line number Diff line number Diff line
@@ -64,12 +64,9 @@ EXPORT_SYMBOL(__bitmap_equal); 


void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)

{

	unsigned int k, lim = bits/BITS_PER_LONG;

	unsigned int k, lim = BITS_TO_LONGS(bits);

	for (k = 0; k < lim; ++k)

		dst[k] = ~src[k];



	if (bits % BITS_PER_LONG)

		dst[k] = ~src[k];

}

EXPORT_SYMBOL(__bitmap_complement);