summaryrefslogtreecommitdiff
path: root/kernel/time/tick-sched.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/time/tick-sched.c')
-rw-r--r--kernel/time/tick-sched.c50
1 files changed, 34 insertions, 16 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 22c57e191..0b1742434 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -36,16 +36,17 @@
*/
static DEFINE_PER_CPU(struct tick_sched, tick_cpu_sched);
-/*
- * The time, when the last jiffy update happened. Protected by jiffies_lock.
- */
-static ktime_t last_jiffies_update;
-
struct tick_sched *tick_get_tick_sched(int cpu)
{
return &per_cpu(tick_cpu_sched, cpu);
}
+#if defined(CONFIG_NO_HZ_COMMON) || defined(CONFIG_HIGH_RES_TIMERS)
+/*
+ * The time, when the last jiffy update happened. Protected by jiffies_lock.
+ */
+static ktime_t last_jiffies_update;
+
/*
* Must be called with interrupts disabled !
*/
@@ -143,7 +144,7 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
* when we go busy again does not account too much ticks.
*/
if (ts->tick_stopped) {
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sched();
if (is_idle_task(current))
ts->idle_jiffies++;
}
@@ -151,6 +152,7 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING);
}
+#endif
#ifdef CONFIG_NO_HZ_FULL
cpumask_var_t tick_nohz_full_mask;
@@ -387,7 +389,7 @@ void __init tick_nohz_init(void)
/*
* NO HZ enabled ?
*/
-static int tick_nohz_enabled __read_mostly = 1;
+int tick_nohz_enabled __read_mostly = 1;
unsigned long tick_nohz_active __read_mostly;
/*
* Enable / Disable tickless mode
@@ -430,7 +432,7 @@ static void tick_nohz_update_jiffies(ktime_t now)
tick_do_update_jiffies64(now);
local_irq_restore(flags);
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sched();
}
/*
@@ -603,15 +605,31 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,
/*
* If the tick is due in the next period, keep it ticking or
- * restart it proper.
+ * force prod the timer.
*/
delta = next_tick - basemono;
if (delta <= (u64)TICK_NSEC) {
tick.tv64 = 0;
+ /*
+ * We've not stopped the tick yet, and there's a timer in the
+ * next period, so no point in stopping it either, bail.
+ */
if (!ts->tick_stopped)
goto out;
+
+ /*
+ * If, OTOH, we did stop it, but there's a pending (expired)
+ * timer reprogram the timer hardware to fire now.
+ *
+ * We will not restart the tick proper, just prod the timer
+ * hardware into firing an interrupt to process the pending
+ * timers. Just like tick_irq_exit() will not restart the tick
+ * for 'normal' interrupts.
+ *
+ * Only once we exit the idle loop will we re-enable the tick,
+ * see tick_nohz_idle_exit().
+ */
if (delta == 0) {
- /* Tick is stopped, but required now. Enforce it */
tick_nohz_restart(ts, now);
goto out;
}
@@ -694,14 +712,14 @@ out:
return tick;
}
-static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now)
+static void tick_nohz_restart_sched_tick(struct tick_sched *ts, ktime_t now, int active)
{
/* Update jiffies first */
tick_do_update_jiffies64(now);
- update_cpu_load_nohz();
+ update_cpu_load_nohz(active);
calc_load_exit_idle();
- touch_softlockup_watchdog();
+ touch_softlockup_watchdog_sched();
/*
* Cancel the scheduled timer and restore the tick
*/
@@ -725,7 +743,7 @@ static void tick_nohz_full_update_tick(struct tick_sched *ts)
if (can_stop_full_tick())
tick_nohz_stop_sched_tick(ts, ktime_get(), cpu);
else if (ts->tick_stopped)
- tick_nohz_restart_sched_tick(ts, ktime_get());
+ tick_nohz_restart_sched_tick(ts, ktime_get(), 1);
#endif
}
@@ -875,7 +893,7 @@ static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
unsigned long ticks;
- if (vtime_accounting_enabled())
+ if (vtime_accounting_cpu_enabled())
return;
/*
* We stopped the tick in idle. Update process times would miss the
@@ -916,7 +934,7 @@ void tick_nohz_idle_exit(void)
tick_nohz_stop_idle(ts, now);
if (ts->tick_stopped) {
- tick_nohz_restart_sched_tick(ts, now);
+ tick_nohz_restart_sched_tick(ts, now, 0);
tick_nohz_account_idle_ticks(ts);
}