diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/tick-common.c | 36 |
1 files changed, 33 insertions, 3 deletions
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 7e5d3524e924..cce4ed1515c7 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -16,6 +16,7 @@ #include <linux/profile.h> #include <linux/sched.h> #include <linux/module.h> +#include <linux/sched/clock.h> #include <trace/events/power.h> #include <asm/irq_regs.h> @@ -84,12 +85,41 @@ int tick_is_oneshot_available(void) static void tick_periodic(int cpu) { if (tick_do_timer_cpu == cpu) { + /* + * Use running_clock() as reference to check for missing ticks. + */ + static ktime_t last_update; + ktime_t now; + int ticks = 1; + + now = ns_to_ktime(running_clock()); write_seqlock(&jiffies_lock); - /* Keep track of the next tick event */ - tick_next_period = ktime_add(tick_next_period, tick_period); + if (last_update) { + u64 delta = ktime_sub(now, last_update); - do_timer(1); + /* + * Check for eventually missed ticks + * + * There is likely a persistent delta between + * last_update and tick_next_period. So they are + * updated separately. + */ + if (delta >= 2 * tick_period) { + s64 period = ktime_to_ns(tick_period); + + ticks = ktime_divns(delta, period); + } + last_update = ktime_add(last_update, + ticks * tick_period); + } else { + last_update = now; + } + + /* Keep track of the next tick event */ + tick_next_period = ktime_add(tick_next_period, + ticks * tick_period); + do_timer(ticks); write_sequnlock(&jiffies_lock); update_wall_time(); } |