Commit-ID: 22aa2ad45fd8a6ef56eb60038fc0ac7059c0a986 Gitweb: http://git.kernel.org/tip/22aa2ad45fd8a6ef56eb60038fc0ac7059c0a986 Author: Frederic Weisbecker <[email protected]> AuthorDate: Fri, 21 Apr 2017 16:00:55 +0200 Committer: Thomas Gleixner <[email protected]> CommitDate: Sun, 23 Apr 2017 13:33:18 +0200
tick: Make sure tick timer is active when bypassing reprogramming So far we have run into too much troubles with the optimization path that skips reprogramming the clock on IRQ exit when the expiration deadline hasn't changed. If by accident the cached deadline happens to be out of sync with the hardware deadline, the buggy result and its cause are hard to investigate. So lets detect and warn about the issue early. Signed-off-by: Frederic Weisbecker <[email protected]> Acked-by: Rik van Riel <[email protected]> Cc: James Hartsock <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: [email protected] Cc: Tim Wright <[email protected]> Cc: Pavel Machek <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> --- kernel/time/tick-sched.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 502b320..be7ca4d 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -783,8 +783,13 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, tick = expires; /* Skip reprogram of event if its not changed */ - if (ts->tick_stopped && (expires == ts->next_tick)) - goto out; + if (ts->tick_stopped && (expires == ts->next_tick)) { + /* Sanity check: make sure clockevent is actually programmed */ + if (likely(dev->next_event <= ts->next_tick)) + goto out; + + WARN_ON_ONCE(1); + } /* * nohz_stop_sched_tick can be called several times before
