static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
/*
- * The time, when the last jiffy update happened. Protected by xtime_lock.
+ * The time, when the last jiffy update happened. Protected by jiffies_lock.
*/
static ktime_t last_jiffies_update;
ktime_t delta;
/*
- * Do a quick check without holding xtime_lock:
+ * Do a quick check without holding jiffies_lock:
*/
delta = ktime_sub(now, last_jiffies_update);
if (delta.tv64 < tick_period.tv64)
return;
- /* Reevalute with xtime_lock held */
- write_seqlock(&xtime_lock);
+ /* Reevalute with jiffies_lock held */
+ write_seqlock(&jiffies_lock);
delta = ktime_sub(now, last_jiffies_update);
if (delta.tv64 >= tick_period.tv64) {
/* Keep the tick_next_period variable up to date */
tick_next_period = ktime_add(last_jiffies_update, tick_period);
}
- write_sequnlock(&xtime_lock);
+ write_sequnlock(&jiffies_lock);
}
/*
{
ktime_t period;
- write_seqlock(&xtime_lock);
+ write_seqlock(&jiffies_lock);
/* Did we start the jiffies update yet ? */
if (last_jiffies_update.tv64 == 0)
last_jiffies_update = tick_next_period;
period = last_jiffies_update;
- write_sequnlock(&xtime_lock);
+ write_sequnlock(&jiffies_lock);
return period;
}
+
+static void tick_sched_do_timer(ktime_t now)
+{
+ int cpu = smp_processor_id();
+
+#ifdef CONFIG_NO_HZ
+ /*
+ * Check if the do_timer duty was dropped. We don't care about
+ * concurrency: This happens only when the cpu in charge went
+ * into a long sleep. If two cpus happen to assign themself to
+ * this duty, then the jiffies update is still serialized by
+ * jiffies_lock.
+ */
+ if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
+ tick_do_timer_cpu = cpu;
+#endif
+
+ /* Check, if the jiffies need an update */
+ if (tick_do_timer_cpu == cpu)
+ tick_do_update_jiffies64(now);
+}
+
+static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
+{
+#ifdef CONFIG_NO_HZ
+ /*
+ * When we are idle and the tick is stopped, we have to touch
+ * the watchdog as we might not schedule for a really long
+ * time. This happens on complete idle SMP systems while
+ * waiting on the login prompt. We also increment the "start of
+ * idle" jiffy stamp so the idle accounting adjustment we do
+ * when we go busy again does not account too much ticks.
+ */
+ if (ts->tick_stopped) {
+ touch_softlockup_watchdog();
+ if (is_idle_task(current))
+ ts->idle_jiffies++;
+ }
+#endif
+ update_process_times(user_mode(regs));
+ profile_tick(CPU_PROFILING);
+}
+
/*
* NOHZ - aka dynamic tick functionality
*/
/* Read jiffies and the time when jiffies were updated last */
do {
- seq = read_seqbegin(&xtime_lock);
+ seq = read_seqbegin(&jiffies_lock);
last_update = last_jiffies_update;
last_jiffies = jiffies;
time_delta = timekeeping_max_deferment();
- } while (read_seqretry(&xtime_lock, seq));
+ } while (read_seqretry(&jiffies_lock, seq));
if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || printk_needs_cpu(cpu) ||
arch_needs_cpu(cpu)) {
{
struct tick_sched *ts = &__get_cpu_var(tick_cpu_sched);
struct pt_regs *regs = get_irq_regs();
- int cpu = smp_processor_id();
ktime_t now = ktime_get();
dev->next_event.tv64 = KTIME_MAX;
- /*
- * Check if the do_timer duty was dropped. We don't care about
- * concurrency: This happens only when the cpu in charge went
- * into a long sleep. If two cpus happen to assign themself to
- * this duty, then the jiffies update is still serialized by
- * xtime_lock.
- */
- if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
- tick_do_timer_cpu = cpu;
-
- /* Check, if the jiffies need an update */
- if (tick_do_timer_cpu == cpu)
- tick_do_update_jiffies64(now);
-
- /*
- * When we are idle and the tick is stopped, we have to touch
- * the watchdog as we might not schedule for a really long
- * time. This happens on complete idle SMP systems while
- * waiting on the login prompt. We also increment the "start
- * of idle" jiffy stamp so the idle accounting adjustment we
- * do when we go busy again does not account too much ticks.
- */
- if (ts->tick_stopped) {
- touch_softlockup_watchdog();
- ts->idle_jiffies++;
- }
-
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING);
+ tick_sched_do_timer(now);
+ tick_sched_handle(ts, regs);
while (tick_nohz_reprogram(ts, now)) {
now = ktime_get();
container_of(timer, struct tick_sched, sched_timer);
struct pt_regs *regs = get_irq_regs();
ktime_t now = ktime_get();
- int cpu = smp_processor_id();
-#ifdef CONFIG_NO_HZ
- /*
- * Check if the do_timer duty was dropped. We don't care about
- * concurrency: This happens only when the cpu in charge went
- * into a long sleep. If two cpus happen to assign themself to
- * this duty, then the jiffies update is still serialized by
- * xtime_lock.
- */
- if (unlikely(tick_do_timer_cpu == TICK_DO_TIMER_NONE))
- tick_do_timer_cpu = cpu;
-#endif
-
- /* Check, if the jiffies need an update */
- if (tick_do_timer_cpu == cpu)
- tick_do_update_jiffies64(now);
+ tick_sched_do_timer(now);
/*
* Do not call, when we are not in irq context and have
* no valid regs pointer
*/
- if (regs) {
- /*
- * When we are idle and the tick is stopped, we have to touch
- * the watchdog as we might not schedule for a really long
- * time. This happens on complete idle SMP systems while
- * waiting on the login prompt. We also increment the "start of
- * idle" jiffy stamp so the idle accounting adjustment we do
- * when we go busy again does not account too much ticks.
- */
- if (ts->tick_stopped) {
- touch_softlockup_watchdog();
- if (is_idle_task(current))
- ts->idle_jiffies++;
- }
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING);
- }
+ if (regs)
+ tick_sched_handle(ts, regs);
hrtimer_forward(timer, now, tick_period);
/* Get the next period (per cpu) */
hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update());
- /* Offset the tick to avert xtime_lock contention. */
+ /* Offset the tick to avert jiffies_lock contention. */
if (sched_skew_tick) {
u64 offset = ktime_to_ns(tick_period) >> 1;
do_div(offset, num_possible_cpus());
projects / firefly-linux-kernel-4.4.55.git / blobdiff