[GIT pull] timer fixes for 2.6.30

From: Thomas Gleixner
Date: Tue May 05 2009 - 06:50:57 EST


Linus,

Please pull the latest timers/urgent git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers/urgent

Thanks,

tglx

------------------>
John Stultz (1):
clockevents: prevent endless loop in tick_handle_periodic()


kernel/time/tick-common.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index 21a5ca8..83c4417 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -93,7 +93,17 @@ void tick_handle_periodic(struct clock_event_device *dev)
for (;;) {
if (!clockevents_program_event(dev, next, ktime_get()))
return;
- tick_periodic(cpu);
+ /*
+ * Have to be careful here. If we're in oneshot mode,
+ * before we call tick_periodic() in a loop, we need
+ * to be sure we're using a real hardware clocksource.
+ * Otherwise we could get trapped in an infinite
+ * loop, as the tick_periodic() increments jiffies,
+ * when then will increment time, posibly causing
+ * the loop to trigger again and again.
+ */
+ if (timekeeping_valid_for_hres())
+ tick_periodic(cpu);
next = ktime_add(next, tick_period);
}
}
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