4 files changed, 65 insertions, 146 deletions

diff --git a/kernel/Kconfig.hz b/kernel/Kconfig.hz
index 526128a2e622..2a202a846757 100644
--- a/kernel/Kconfig.hz
+++ b/kernel/Kconfig.hz
@@ -55,4 +55,4 @@ config HZ
         default 1000 if HZ_1000
 
 config SCHED_HRTICK
-        def_bool HIGH_RES_TIMERS && X86
+        def_bool HIGH_RES_TIMERS
diff --git a/kernel/sched.c b/kernel/sched.c
index c237624a8a04..85cf246cfdf5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -571,8 +571,10 @@ struct rq {
 #endif
 
 #ifdef CONFIG_SCHED_HRTICK
-        unsigned long hrtick_flags;
-        ktime_t hrtick_expire;
+#ifdef CONFIG_SMP
+        int hrtick_csd_pending;
+        struct call_single_data hrtick_csd;
+#endif
         struct hrtimer hrtick_timer;
 #endif
 
@@ -983,13 +985,6 @@ static struct rq *this_rq_lock(void)
         return rq;
 }
 
-static void __resched_task(struct task_struct *p, int tif_bit);
-
-static inline void resched_task(struct task_struct *p)
-{
-        __resched_task(p, TIF_NEED_RESCHED);
-}
-
 #ifdef CONFIG_SCHED_HRTICK
 /*
  * Use HR-timers to deliver accurate preemption points.
@@ -1001,25 +996,6 @@ static inline void resched_task(struct task_struct *p)
  * When we get rescheduled we reprogram the hrtick_timer outside of the
  * rq->lock.
  */
-static inline void resched_hrt(struct task_struct *p)
-{
-        __resched_task(p, TIF_HRTICK_RESCHED);
-}
-
-static inline void resched_rq(struct rq *rq)
-{
-        unsigned long flags;
-
-        spin_lock_irqsave(&rq->lock, flags);
-        resched_task(rq->curr);
-        spin_unlock_irqrestore(&rq->lock, flags);
-}
-
-enum {
-        HRTICK_SET,             /* re-programm hrtick_timer */
-        HRTICK_RESET,           /* not a new slice */
-        HRTICK_BLOCK,           /* stop hrtick operations */
-};
 
 /*
  * Use hrtick when:
@@ -1030,40 +1006,11 @@ static inline int hrtick_enabled(struct rq *rq)
 {
         if (!sched_feat(HRTICK))
                 return 0;
-        if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags)))
+        if (!cpu_online(cpu_of(rq)))
                 return 0;
         return hrtimer_is_hres_active(&rq->hrtick_timer);
 }
 
-/*
- * Called to set the hrtick timer state.
- *
- * called with rq->lock held and irqs disabled
- */
-static void hrtick_start(struct rq *rq, u64 delay, int reset)
-{
-        assert_spin_locked(&rq->lock);
-
-        /*
-         * preempt at: now + delay
-         */
-        rq->hrtick_expire =
-                ktime_add_ns(rq->hrtick_timer.base->get_time(), delay);
-        /*
-         * indicate we need to program the timer
-         */
-        __set_bit(HRTICK_SET, &rq->hrtick_flags);
-        if (reset)
-                __set_bit(HRTICK_RESET, &rq->hrtick_flags);
-
-        /*
-         * New slices are called from the schedule path and don't need a
-         * forced reschedule.
-         */
-        if (reset)
-                resched_hrt(rq->curr);
-}
-
 static void hrtick_clear(struct rq *rq)
 {
         if (hrtimer_active(&rq->hrtick_timer))
@@ -1071,32 +1018,6 @@ static void hrtick_clear(struct rq *rq)
 }
 
 /*
- * Update the timer from the possible pending state.
- */
-static void hrtick_set(struct rq *rq)
-{
-        ktime_t time;
-        int set, reset;
-        unsigned long flags;
-
-        WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
-
-        spin_lock_irqsave(&rq->lock, flags);
-        set = __test_and_clear_bit(HRTICK_SET, &rq->hrtick_flags);
-        reset = __test_and_clear_bit(HRTICK_RESET, &rq->hrtick_flags);
-        time = rq->hrtick_expire;
-        clear_thread_flag(TIF_HRTICK_RESCHED);
-        spin_unlock_irqrestore(&rq->lock, flags);
-
-        if (set) {
-                hrtimer_start(&rq->hrtick_timer, time, HRTIMER_MODE_ABS);
-                if (reset && !hrtimer_active(&rq->hrtick_timer))
-                        resched_rq(rq);
-        } else
-                hrtick_clear(rq);
-}
-
-/*
  * High-resolution timer tick.
  * Runs from hardirq context with interrupts disabled.
  */
@@ -1115,27 +1036,37 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
 }
 
 #ifdef CONFIG_SMP
-static void hotplug_hrtick_disable(int cpu)
+/*
+ * called from hardirq (IPI) context
+ */
+static void __hrtick_start(void *arg)
 {
-        struct rq *rq = cpu_rq(cpu);
-        unsigned long flags;
-
-        spin_lock_irqsave(&rq->lock, flags);
-        rq->hrtick_flags = 0;
-        __set_bit(HRTICK_BLOCK, &rq->hrtick_flags);
-        spin_unlock_irqrestore(&rq->lock, flags);
+        struct rq *rq = arg;
 
-        hrtick_clear(rq);
+        spin_lock(&rq->lock);
+        hrtimer_restart(&rq->hrtick_timer);
+        rq->hrtick_csd_pending = 0;
+        spin_unlock(&rq->lock);
 }
 
-static void hotplug_hrtick_enable(int cpu)
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+static void hrtick_start(struct rq *rq, u64 delay)
 {
-        struct rq *rq = cpu_rq(cpu);
-        unsigned long flags;
+        struct hrtimer *timer = &rq->hrtick_timer;
+        ktime_t time = ktime_add_ns(timer->base->get_time(), delay);
 
-        spin_lock_irqsave(&rq->lock, flags);
-        __clear_bit(HRTICK_BLOCK, &rq->hrtick_flags);
-        spin_unlock_irqrestore(&rq->lock, flags);
+        timer->expires = time;
+
+        if (rq == this_rq()) {
+                hrtimer_restart(timer);
+        } else if (!rq->hrtick_csd_pending) {
+                __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
+                rq->hrtick_csd_pending = 1;
+        }
 }
 
 static int
@@ -1150,16 +1081,7 @@ hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
         case CPU_DOWN_PREPARE_FROZEN:
         case CPU_DEAD:
         case CPU_DEAD_FROZEN:
-                hotplug_hrtick_disable(cpu);
-                return NOTIFY_OK;
-
-        case CPU_UP_PREPARE:
-        case CPU_UP_PREPARE_FROZEN:
-        case CPU_DOWN_FAILED:
-        case CPU_DOWN_FAILED_FROZEN:
-        case CPU_ONLINE:
-        case CPU_ONLINE_FROZEN:
-                hotplug_hrtick_enable(cpu);
+                hrtick_clear(cpu_rq(cpu));
                 return NOTIFY_OK;
         }
 
@@ -1170,46 +1092,45 @@ static void init_hrtick(void)
 {
         hotcpu_notifier(hotplug_hrtick, 0);
 }
-#endif /* CONFIG_SMP */
+#else
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+static void hrtick_start(struct rq *rq, u64 delay)
+{
+        hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
+}
 
-static void init_rq_hrtick(struct rq *rq)
+static void init_hrtick(void)
 {
-        rq->hrtick_flags = 0;
-        hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-        rq->hrtick_timer.function = hrtick;
-        rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
 }
+#endif /* CONFIG_SMP */
 
-void hrtick_resched(void)
+static void init_rq_hrtick(struct rq *rq)
 {
-        struct rq *rq;
-        unsigned long flags;
+#ifdef CONFIG_SMP
+        rq->hrtick_csd_pending = 0;
 
-        if (!test_thread_flag(TIF_HRTICK_RESCHED))
-                return;
+        rq->hrtick_csd.flags = 0;
+        rq->hrtick_csd.func = __hrtick_start;
+        rq->hrtick_csd.info = rq;
+#endif
 
-        local_irq_save(flags);
-        rq = cpu_rq(smp_processor_id());
-        hrtick_set(rq);
-        local_irq_restore(flags);
+        hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+        rq->hrtick_timer.function = hrtick;
+        rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
 }
 #else
 static inline void hrtick_clear(struct rq *rq)
 {
 }
 
-static inline void hrtick_set(struct rq *rq)
-{
-}
-
 static inline void init_rq_hrtick(struct rq *rq)
 {
 }
 
-void hrtick_resched(void)
-{
-}
-
 static inline void init_hrtick(void)
 {
 }
@@ -1228,16 +1149,16 @@ static inline void init_hrtick(void)
 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
 #endif
 
-static void __resched_task(struct task_struct *p, int tif_bit)
+static void resched_task(struct task_struct *p)
 {
         int cpu;
 
         assert_spin_locked(&task_rq(p)->lock);
 
-        if (unlikely(test_tsk_thread_flag(p, tif_bit)))
+        if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
                 return;
 
-        set_tsk_thread_flag(p, tif_bit);
+        set_tsk_thread_flag(p, TIF_NEED_RESCHED);
 
         cpu = task_cpu(p);
         if (cpu == smp_processor_id())
@@ -1303,10 +1224,10 @@ void wake_up_idle_cpu(int cpu)
 #endif /* CONFIG_NO_HZ */
 
 #else /* !CONFIG_SMP */
-static void __resched_task(struct task_struct *p, int tif_bit)
+static void resched_task(struct task_struct *p)
 {
         assert_spin_locked(&task_rq(p)->lock);
-        set_tsk_thread_flag(p, tif_bit);
+        set_tsk_need_resched(p);
 }
 #endif /* CONFIG_SMP */
 
@@ -4395,7 +4316,7 @@ asmlinkage void __sched schedule(void)
         struct task_struct *prev, *next;
         unsigned long *switch_count;
         struct rq *rq;
-        int cpu, hrtick = sched_feat(HRTICK);
+        int cpu;
 
 need_resched:
         preempt_disable();
@@ -4410,7 +4331,7 @@ need_resched_nonpreemptible:
 
         schedule_debug(prev);
 
-        if (hrtick)
+        if (sched_feat(HRTICK))
                 hrtick_clear(rq);
 
         /*
@@ -4457,9 +4378,6 @@ need_resched_nonpreemptible:
         } else
                 spin_unlock_irq(&rq->lock);
 
-        if (hrtick)
-                hrtick_set(rq);
-
         if (unlikely(reacquire_kernel_lock(current) < 0))
                 goto need_resched_nonpreemptible;
 
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index d924c679dfac..7f700263f04c 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -878,7 +878,6 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
 #ifdef CONFIG_SCHED_HRTICK
 static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
 {
-        int requeue = rq->curr == p;
         struct sched_entity *se = &p->se;
         struct cfs_rq *cfs_rq = cfs_rq_of(se);
 
@@ -899,10 +898,10 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
                  * Don't schedule slices shorter than 10000ns, that just
                  * doesn't make sense. Rely on vruntime for fairness.
                  */
-                if (!requeue)
+                if (rq->curr != p)
                         delta = max(10000LL, delta);
 
-                hrtick_start(rq, delta, requeue);
+                hrtick_start(rq, delta);
         }
 }
 #else /* !CONFIG_SCHED_HRTICK */
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 50735bb96149..24621cea8bb0 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -505,7 +505,9 @@ void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
         rt_rq->rt_nr_running++;
 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
         if (rt_se_prio(rt_se) < rt_rq->highest_prio) {
+#ifdef CONFIG_SMP
                 struct rq *rq = rq_of_rt_rq(rt_rq);
+#endif
 
                 rt_rq->highest_prio = rt_se_prio(rt_se);
 #ifdef CONFIG_SMP