Currently we are iterating over all possible (currently four) bits of
active_bases to see if corresponding clock bases are active. This is good enough
for cases where 3 or 4 bases are used but if only 1 or 2 are used then it makes
more sense to use __ffs() to find the right bit directly.
Suggested-by: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
---
V1->V2: Instead of removing active_bases use __ffs() on it to make loop more
efficient.
I tried to use for_each_set_bit() first and then it looked overdone. And so used
a simple form, __ffs() with some code to clear bits.
kernel/hrtimer.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index acfef5f..ea90228 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1265,6 +1265,7 @@ void hrtimer_interrupt(struct clock_event_device *dev)
{
struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
ktime_t expires_next, now, entry_time, delta;
+ unsigned long active_bases = cpu_base->active_bases;
int i, retries = 0;
BUG_ON(!cpu_base->hres_active);
@@ -1284,15 +1285,11 @@ retry:
*/
cpu_base->expires_next.tv64 = KTIME_MAX;
- for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
- struct hrtimer_clock_base *base;
+ while ((i = __ffs(active_bases))) {
+ struct hrtimer_clock_base *base = cpu_base->clock_base + i;
struct timerqueue_node *node;
ktime_t basenow;
- if (!(cpu_base->active_bases & (1 << i)))
- continue;
-
- base = cpu_base->clock_base + i;
basenow = ktime_add(now, base->offset);
while ((node = timerqueue_getnext(&base->active))) {
@@ -1327,6 +1324,8 @@ retry:
__run_hrtimer(timer, &basenow);
}
+
+ active_bases &= ~(1 << i);
}
/*
--
1.7.12.rc2.18.g61b472e
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