1 files changed, 56 insertions, 33 deletions

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index cb89fa8db110..63f24b550695 100644
--- 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>
@@ -143,6 +143,44 @@ void tick_nohz_update_jiffies(void)
         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
  *
@@ -153,14 +191,16 @@ void tick_nohz_update_jiffies(void)
 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);
 
         /*
@@ -192,19 +232,7 @@ 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);
@@ -216,6 +244,10 @@ void tick_nohz_stop_sched_tick(void)
         next_jiffies = get_next_timer_interrupt(last_jiffies);
         delta_jiffies = next_jiffies - last_jiffies;
 
+        rt_jiffies = rt_needs_cpu(cpu);
+        if (rt_jiffies && rt_jiffies < delta_jiffies)
+                delta_jiffies = rt_jiffies;
+
         if (rcu_needs_cpu(cpu))
                 delta_jiffies = 1;
         /*
@@ -291,7 +323,7 @@ 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
@@ -332,23 +364,22 @@ 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();
-
-        local_irq_disable();
         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
@@ -502,14 +533,13 @@ 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();
@@ -547,15 +577,8 @@ 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 */