[PATCH] hrtimer: call get_softirq_time() only when necessary in run_hrtimer_queue()

It seems that run_hrtimer_queue() is calling get_softirq_time() more
often than it needs to.

With this patch, it only calls get_softirq_time() if there's a
pending timer.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 49cbf7cffebd..f181ff4dd32e 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -606,6 +606,9 @@ static inline void run_hrtimer_queue(struct hrtimer_base *base)
 {
         struct rb_node *node;
 
+        if (!base->first)
+                return;
+
         if (base->get_softirq_time)
                 base->softirq_time = base->get_softirq_time();