Merge branches 'timers-core-for-linus' and 'timers-urgent-for-linus' of git://git...

[cascardo/linux.git] / kernel / time / tick-sched.c

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 7c7ec45..99ef0df 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -603,15 +603,31 @@ 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;
                }
@@ -694,11 +710,11 @@ 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();
@@ -725,7 +741,7 @@ 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 +891,7 @@ 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 +932,7 @@ 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);
        }