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: Yury Norov <ynorov@caviumnetworks.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/bitmap.c b/lib/bitmap.c
index a42eff7..58f9750 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -64,12 +64,9 @@
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);