[PATCH] lib: micro-optimization for __bitmap_complement()

From: Yury Norov
Date: Wed Apr 11 2018 - 10:59:37 EST


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.

Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
---
lib/bitmap.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index c82c61b66e16..7adc10074cff 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -62,12 +62,9 @@ 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);

--
2.14.1