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authorIngo Molnar <mingo@elte.hu>2008-05-12 15:43:53 +0200
committerIngo Molnar <mingo@elte.hu>2008-05-30 14:16:10 +0200
commit7a14ce1d8c1d3a6118d406e64eaf9aa70375e085 (patch)
tree01a0d9f785a849fc4242d024bd1afa7deb7c1bf6 /kernel/time
parent916941b2bfd9c4a8b66855f198ae16c3f51ef570 (diff)
downloadlinux-7a14ce1d8c1d3a6118d406e64eaf9aa70375e085.tar.gz
nohz: reduce jiffies polling overhead
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index b854a895591e..cb75394ed00e 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -48,6 +48,13 @@ static void tick_do_update_jiffies64(ktime_t now)
unsigned long ticks = 0;
ktime_t delta;
+ /*
+ * Do a quick check without holding xtime_lock:
+ */
+ delta = ktime_sub(now, last_jiffies_update);
+ if (delta.tv64 < tick_period.tv64)
+ return;
+
/* Reevalute with xtime_lock held */
write_seqlock(&xtime_lock);