Merge branch 'for-linus' of git://git.infradead.org/~dedekind/ubi-2.6

[sfrench/cifs-2.6.git] / kernel / time / tick-sched.c

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 5f9fb645b725edabb94a9f831631be126acc41d6..2968298f8f364923010c440fe68f6e02d2f32e2a 100644 (file)
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -9,7 +9,7 @@
  *
  *  Started by: Thomas Gleixner and Ingo Molnar
  *
- *  For licencing details see kernel-base/COPYING
+ *  Distribute under GPLv2.
  */
 #include <linux/cpu.h>
 #include <linux/err.h>
@@ -137,12 +137,51 @@ void tick_nohz_update_jiffies(void)
 
        cpu_clear(cpu, nohz_cpu_mask);
        now = ktime_get();
+       ts->idle_waketime = now;
 
        local_irq_save(flags);
        tick_do_update_jiffies64(now);
        local_irq_restore(flags);
 }
 
+void tick_nohz_stop_idle(int cpu)
+{
+       struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+       if (ts->idle_active) {
+               ktime_t now, delta;
+               now = ktime_get();
+               delta = ktime_sub(now, ts->idle_entrytime);
+               ts->idle_lastupdate = now;
+               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+               ts->idle_active = 0;
+       }
+}
+
+static ktime_t tick_nohz_start_idle(int cpu)
+{
+       struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+       ktime_t now, delta;
+
+       now = ktime_get();
+       if (ts->idle_active) {
+               delta = ktime_sub(now, ts->idle_entrytime);
+               ts->idle_lastupdate = now;
+               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
+       }
+       ts->idle_entrytime = now;
+       ts->idle_active = 1;
+       return now;
+}
+
+u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
+{
+       struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
+
+       *last_update_time = ktime_to_us(ts->idle_lastupdate);
+       return ktime_to_us(ts->idle_sleeptime);
+}
+
 /**
  * tick_nohz_stop_sched_tick - stop the idle tick from the idle task
  *
@@ -155,13 +194,14 @@ void tick_nohz_stop_sched_tick(void)
        unsigned long seq, last_jiffies, next_jiffies, delta_jiffies, flags;
        unsigned long rt_jiffies;
        struct tick_sched *ts;
-       ktime_t last_update, expires, now, delta;
+       ktime_t last_update, expires, now;
        struct clock_event_device *dev = __get_cpu_var(tick_cpu_device).evtdev;
        int cpu;
 
        local_irq_save(flags);
 
        cpu = smp_processor_id();
+       now = tick_nohz_start_idle(cpu);
        ts = &per_cpu(tick_cpu_sched, cpu);
 
        /*
@@ -193,19 +233,7 @@ void tick_nohz_stop_sched_tick(void)
                }
        }
 
-       now = ktime_get();
-       /*
-        * When called from irq_exit we need to account the idle sleep time
-        * correctly.
-        */
-       if (ts->tick_stopped) {
-               delta = ktime_sub(now, ts->idle_entrytime);
-               ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-       }
-
-       ts->idle_entrytime = now;
        ts->idle_calls++;
-
        /* Read jiffies and the time when jiffies were updated last */
        do {
                seq = read_seqbegin(&xtime_lock);
@@ -254,6 +282,7 @@ void tick_nohz_stop_sched_tick(void)
                        ts->idle_tick = ts->sched_timer.expires;
                        ts->tick_stopped = 1;
                        ts->idle_jiffies = last_jiffies;
+                       rcu_enter_nohz();
                }
 
                /*
@@ -296,7 +325,7 @@ void tick_nohz_stop_sched_tick(void)
                        /* Check, if the timer was already in the past */
                        if (hrtimer_active(&ts->sched_timer))
                                goto out;
-               } else if(!tick_program_event(expires, 0))
+               } else if (!tick_program_event(expires, 0))
                                goto out;
                /*
                 * We are past the event already. So we crossed a
@@ -337,23 +366,24 @@ void tick_nohz_restart_sched_tick(void)
        int cpu = smp_processor_id();
        struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
        unsigned long ticks;
-       ktime_t now, delta;
+       ktime_t now;
 
-       if (!ts->tick_stopped)
+       local_irq_disable();
+       tick_nohz_stop_idle(cpu);
+
+       if (!ts->tick_stopped) {
+               local_irq_enable();
                return;
+       }
 
-       /* Update jiffies first */
-       now = ktime_get();
+       rcu_exit_nohz();
 
-       local_irq_disable();
+       /* Update jiffies first */
        select_nohz_load_balancer(0);
+       now = ktime_get();
        tick_do_update_jiffies64(now);
        cpu_clear(cpu, nohz_cpu_mask);
 
-       /* Account the idle time */
-       delta = ktime_sub(now, ts->idle_entrytime);
-       ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
-
        /*
         * We stopped the tick in idle. Update process times would miss the
         * time we slept as update_process_times does only a 1 tick
@@ -374,6 +404,7 @@ void tick_nohz_restart_sched_tick(void)
         * Cancel the scheduled timer and restore the tick
         */
        ts->tick_stopped  = 0;
+       ts->idle_exittime = now;
        hrtimer_cancel(&ts->sched_timer);
        ts->sched_timer.expires = ts->idle_tick;
 
@@ -507,14 +538,13 @@ static inline void tick_nohz_switch_to_nohz(void) { }
  */
 #ifdef CONFIG_HIGH_RES_TIMERS
 /*
- * We rearm the timer until we get disabled by the idle code
+ * We rearm the timer until we get disabled by the idle code.
  * Called with interrupts disabled and timer->base->cpu_base->lock held.
  */
 static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
 {
        struct tick_sched *ts =
                container_of(timer, struct tick_sched, sched_timer);
-       struct hrtimer_cpu_base *base = timer->base->cpu_base;
        struct pt_regs *regs = get_irq_regs();
        ktime_t now = ktime_get();
        int cpu = smp_processor_id();
@@ -552,15 +582,8 @@ static enum hrtimer_restart tick_sched_timer(struct hrtimer *timer)
                        touch_softlockup_watchdog();
                        ts->idle_jiffies++;
                }
-               /*
-                * update_process_times() might take tasklist_lock, hence
-                * drop the base lock. sched-tick hrtimers are per-CPU and
-                * never accessible by userspace APIs, so this is safe to do.
-                */
-               spin_unlock(&base->lock);
                update_process_times(user_mode(regs));
                profile_tick(CPU_PROFILING);
-               spin_lock(&base->lock);
        }
 
        /* Do not restart, when we are in the idle loop */
@@ -661,7 +684,7 @@ int tick_check_oneshot_change(int allow_nohz)
        if (ts->nohz_mode != NOHZ_MODE_INACTIVE)
                return 0;
 
-       if (!timekeeping_is_continuous() || !tick_is_oneshot_available())
+       if (!timekeeping_valid_for_hres() || !tick_is_oneshot_available())
                return 0;
 
        if (!allow_nohz)