#include <linux/reciprocal_div.h>
#include <linux/unistd.h>
#include <linux/pagemap.h>
+#include <linux/hrtimer.h>
#include <asm/tlb.h>
#include <asm/irq_regs.h>
struct list_head migration_queue;
#endif
+#ifdef CONFIG_SCHED_HRTICK
+ unsigned long hrtick_flags;
+ ktime_t hrtick_expire;
+ struct hrtimer hrtick_timer;
+#endif
+
#ifdef CONFIG_SCHEDSTATS
/* latency stats */
struct sched_info rq_sched_info;
SCHED_FEAT_START_DEBIT = 4,
SCHED_FEAT_TREE_AVG = 8,
SCHED_FEAT_APPROX_AVG = 16,
+ SCHED_FEAT_HRTICK = 32,
+ SCHED_FEAT_DOUBLE_TICK = 64,
};
const_debug unsigned int sysctl_sched_features =
SCHED_FEAT_WAKEUP_PREEMPT * 1 |
SCHED_FEAT_START_DEBIT * 1 |
SCHED_FEAT_TREE_AVG * 0 |
- SCHED_FEAT_APPROX_AVG * 0;
+ SCHED_FEAT_APPROX_AVG * 0 |
+ SCHED_FEAT_HRTICK * 1 |
+ SCHED_FEAT_DOUBLE_TICK * 0;
#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
}
EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
+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.
+ *
+ * Its all a bit involved since we cannot program an hrt while holding the
+ * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
+ * reschedule event.
+ *
+ * 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 */
+};
+
+/*
+ * Use hrtick when:
+ * - enabled by features
+ * - hrtimer is actually high res
+ */
+static inline int hrtick_enabled(struct rq *rq)
+{
+ if (!sched_feat(HRTICK))
+ 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))
+ hrtimer_cancel(&rq->hrtick_timer);
+}
+
+/*
+ * 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.
+ */
+static enum hrtimer_restart hrtick(struct hrtimer *timer)
+{
+ struct rq *rq = container_of(timer, struct rq, hrtick_timer);
+
+ WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
+
+ spin_lock(&rq->lock);
+ __update_rq_clock(rq);
+ rq->curr->sched_class->task_tick(rq, rq->curr, 1);
+ spin_unlock(&rq->lock);
+
+ return HRTIMER_NORESTART;
+}
+
+static inline void init_rq_hrtick(struct rq *rq)
+{
+ 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;
+}
+
+void hrtick_resched(void)
+{
+ struct rq *rq;
+ unsigned long flags;
+
+ if (!test_thread_flag(TIF_HRTICK_RESCHED))
+ return;
+
+ local_irq_save(flags);
+ rq = cpu_rq(smp_processor_id());
+ hrtick_set(rq);
+ local_irq_restore(flags);
+}
+#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)
+{
+}
+#endif
+
/*
* resched_task - mark a task 'to be rescheduled now'.
*
#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
#endif
-static void resched_task(struct task_struct *p)
+static void __resched_task(struct task_struct *p, int tif_bit)
{
int cpu;
assert_spin_locked(&task_rq(p)->lock);
- if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+ if (unlikely(test_tsk_thread_flag(p, tif_bit)))
return;
- set_tsk_thread_flag(p, TIF_NEED_RESCHED);
+ set_tsk_thread_flag(p, tif_bit);
cpu = task_cpu(p);
if (cpu == smp_processor_id())
spin_unlock_irqrestore(&rq->lock, flags);
}
#else
-static inline void resched_task(struct task_struct *p)
+static void __resched_task(struct task_struct *p, int tif_bit)
{
assert_spin_locked(&task_rq(p)->lock);
- set_tsk_need_resched(p);
+ set_tsk_thread_flag(p, tif_bit);
}
#endif
rq->tick_timestamp = rq->clock;
update_cpu_load(rq);
if (curr != rq->idle) /* FIXME: needed? */
- curr->sched_class->task_tick(rq, curr);
+ curr->sched_class->task_tick(rq, curr, 0);
spin_unlock(&rq->lock);
#ifdef CONFIG_SMP
schedule_debug(prev);
+ hrtick_clear(rq);
+
/*
* Do the rq-clock update outside the rq lock:
*/
++*switch_count;
context_switch(rq, prev, next); /* unlocks the rq */
+ /*
+ * the context switch might have flipped the stack from under
+ * us, hence refresh the local variables.
+ */
+ cpu = smp_processor_id();
+ rq = cpu_rq(cpu);
} else
spin_unlock_irq(&rq->lock);
- if (unlikely(reacquire_kernel_lock(current) < 0)) {
- cpu = smp_processor_id();
- rq = cpu_rq(cpu);
+ hrtick_set(rq);
+
+ if (unlikely(reacquire_kernel_lock(current) < 0))
goto need_resched_nonpreemptible;
- }
+
preempt_enable_no_resched();
if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
goto need_resched;
rq->rt.overloaded = 0;
rq_attach_root(rq, &def_root_domain);
#endif
+ init_rq_hrtick(rq);
+
atomic_set(&rq->nr_iowait, 0);
array = &rq->rt.active;
git.openpandora.org / pandora-kernel.git / blobdiff