commit c731a27c67d5200f71ba78613b2e7ad87284d1e7
author Felix Fietkau <nbd@openwrt.org> Fri May 04 21:08:33 2012 -0700
committer William Bellavance <flintman@flintmancomputers.com> Wed Jul 13 07:02:28 2016 -0400
tree dfd4e5af6eaa62f7878f60fcefa5ec845023694f
parent dbc29455e7c6c0cfd8f15d4586ef67acfd3e55ca

timer: optimize apply_slack()

__fls(mask) is equivalent to find_last_bit(&mask, BITS_PER_LONG), but cheaper.
find_last_bit was showing up high on the list when I was profiling for stalls
on icache misses on a system with very small cache size (MIPS).

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: edoko <r_data@naver.com>

Change-Id: I8a5021a2fb2936c00ffd456663a76cb1b23e3100

kernel/timer.c

diff --git a/kernel/timer.c b/kernel/timer.c
index 441e6d0..0d19b32 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -814,7 +814,7 @@
 	if (mask == 0)
 		return expires;
 
-	bit = find_last_bit(&mask, BITS_PER_LONG);
+	bit = __fls(mask);
 
 	mask = (1UL << bit) - 1;