diff options
Diffstat (limited to 'kernel/sched/clock.c')
| -rw-r--r-- | kernel/sched/clock.c | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index dc650851935f..f861637f7fdc 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -366,20 +366,38 @@ void sched_clock_tick(void) { struct sched_clock_data *scd; + if (sched_clock_stable()) + return; + + if (unlikely(!sched_clock_running)) + return; + WARN_ON_ONCE(!irqs_disabled()); - /* - * Update these values even if sched_clock_stable(), because it can - * become unstable at any point in time at which point we need some - * values to fall back on. - * - * XXX arguably we can skip this if we expose tsc_clocksource_reliable - */ scd = this_scd(); __scd_stamp(scd); + sched_clock_local(scd); +} + +void sched_clock_tick_stable(void) +{ + u64 gtod, clock; - if (!sched_clock_stable() && likely(sched_clock_running)) - sched_clock_local(scd); + if (!sched_clock_stable()) + return; + + /* + * Called under watchdog_lock. + * + * The watchdog just found this TSC to (still) be stable, so now is a + * good moment to update our __gtod_offset. Because once we find the + * TSC to be unstable, any computation will be computing crap. + */ + local_irq_disable(); + gtod = ktime_get_ns(); + clock = sched_clock(); + __gtod_offset = (clock + __sched_clock_offset) - gtod; + local_irq_enable(); } /* |