[PATCH] sched: make cpu_clock() not use the rq clock

[pandora-kernel.git] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index 93cf241..3eed860 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -263,8 +263,6 @@ struct rq {
        unsigned int clock_warps, clock_overflows;
        unsigned int clock_unstable_events;
 
-       struct sched_class *load_balance_class;
-
        atomic_t nr_iowait;
 
 #ifdef CONFIG_SMP
@@ -385,13 +383,12 @@ static inline unsigned long long rq_clock(struct rq *rq)
  */
 unsigned long long cpu_clock(int cpu)
 {
-       struct rq *rq = cpu_rq(cpu);
        unsigned long long now;
        unsigned long flags;
 
-       spin_lock_irqsave(&rq->lock, flags);
-       now = rq_clock(rq);
-       spin_unlock_irqrestore(&rq->lock, flags);
+       local_irq_save(flags);
+       now = rq_clock(cpu_rq(cpu));
+       local_irq_restore(flags);
 
        return now;
 }
@@ -1592,6 +1589,10 @@ static void __sched_fork(struct task_struct *p)
        INIT_LIST_HEAD(&p->run_list);
        p->se.on_rq = 0;
 
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+       INIT_HLIST_HEAD(&p->preempt_notifiers);
+#endif
+
        /*
         * We mark the process as running here, but have not actually
         * inserted it onto the runqueue yet. This guarantees that
@@ -1673,6 +1674,63 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
        task_rq_unlock(rq, &flags);
 }
 
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+/**
+ * preempt_notifier_register - tell me when current is being being preempted
+ *                         and rescheduled
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+       hlist_add_head(&notifier->link, &current->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ *
+ * This is safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+       hlist_del(&notifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+       struct preempt_notifier *notifier;
+       struct hlist_node *node;
+
+       hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
+               notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+                                struct task_struct *next)
+{
+       struct preempt_notifier *notifier;
+       struct hlist_node *node;
+
+       hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
+               notifier->ops->sched_out(notifier, next);
+}
+
+#else
+
+static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+                                struct task_struct *next)
+{
+}
+
+#endif
+
 /**
  * prepare_task_switch - prepare to switch tasks
  * @rq: the runqueue preparing to switch
@@ -1685,8 +1743,11 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
  * prepare_task_switch sets up locking and calls architecture specific
  * hooks.
  */
-static inline void prepare_task_switch(struct rq *rq, struct task_struct *next)
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+                   struct task_struct *next)
 {
+       fire_sched_out_preempt_notifiers(prev, next);
        prepare_lock_switch(rq, next);
        prepare_arch_switch(next);
 }
@@ -1728,6 +1789,7 @@ static inline void finish_task_switch(struct rq *rq, struct task_struct *prev)
        prev_state = prev->state;
        finish_arch_switch(prev);
        finish_lock_switch(rq, prev);
+       fire_sched_in_preempt_notifiers(current);
        if (mm)
                mmdrop(mm);
        if (unlikely(prev_state == TASK_DEAD)) {
@@ -1768,7 +1830,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
 {
        struct mm_struct *mm, *oldmm;
 
-       prepare_task_switch(rq, next);
+       prepare_task_switch(rq, prev, next);
        mm = next->mm;
        oldmm = prev->active_mm;
        /*
@@ -6335,6 +6397,10 @@ void __init sched_init(void)
 
        set_load_weight(&init_task);
 
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+       INIT_HLIST_HEAD(&init_task.preempt_notifiers);
+#endif
+
 #ifdef CONFIG_SMP
        nr_cpu_ids = highest_cpu + 1;
        open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);