Merge commit 'v2.6.29-rc7' into perfcounters/core
[linux-2.6.git] / kernel / sched.c
index 40d70d9..78f4424 100644 (file)
@@ -223,7 +223,7 @@ static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
 {
        ktime_t now;
 
-       if (rt_bandwidth_enabled() && rt_b->rt_runtime == RUNTIME_INF)
+       if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
                return;
 
        if (hrtimer_active(&rt_b->rt_period_timer))
@@ -558,6 +558,7 @@ struct rq {
        struct load_weight load;
        unsigned long nr_load_updates;
        u64 nr_switches;
+       u64 nr_migrations_in;
 
        struct cfs_rq cfs;
        struct rt_rq rt;
@@ -1908,6 +1909,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
 #endif
        if (old_cpu != new_cpu) {
                p->se.nr_migrations++;
+               new_rq->nr_migrations_in++;
 #ifdef CONFIG_SCHEDSTATS
                if (task_hot(p, old_rq->clock, NULL))
                        schedstat_inc(p, se.nr_forced2_migrations);
@@ -2811,6 +2813,21 @@ unsigned long nr_active(void)
 }
 
 /*
+ * Externally visible per-cpu scheduler statistics:
+ * cpu_nr_switches(cpu) - number of context switches on that cpu
+ * cpu_nr_migrations(cpu) - number of migrations into that cpu
+ */
+u64 cpu_nr_switches(int cpu)
+{
+       return cpu_rq(cpu)->nr_switches;
+}
+
+u64 cpu_nr_migrations(int cpu)
+{
+       return cpu_rq(cpu)->nr_migrations_in;
+}
+
+/*
  * Update rq->cpu_load[] statistics. This function is usually called every
  * scheduler tick (TICK_NSEC).
  */
@@ -3925,19 +3942,24 @@ int select_nohz_load_balancer(int stop_tick)
        int cpu = smp_processor_id();
 
        if (stop_tick) {
-               cpumask_set_cpu(cpu, nohz.cpu_mask);
                cpu_rq(cpu)->in_nohz_recently = 1;
 
-               /*
-                * If we are going offline and still the leader, give up!
-                */
-               if (!cpu_active(cpu) &&
-                   atomic_read(&nohz.load_balancer) == cpu) {
+               if (!cpu_active(cpu)) {
+                       if (atomic_read(&nohz.load_balancer) != cpu)
+                               return 0;
+
+                       /*
+                        * If we are going offline and still the leader,
+                        * give up!
+                        */
                        if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
                                BUG();
+
                        return 0;
                }
 
+               cpumask_set_cpu(cpu, nohz.cpu_mask);
+
                /* time for ilb owner also to sleep */
                if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
                        if (atomic_read(&nohz.load_balancer) == cpu)
@@ -4757,8 +4779,8 @@ EXPORT_SYMBOL(default_wake_function);
  * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
  * zero in this (rare) case, and we handle it by continuing to scan the queue.
  */
-static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
-                            int nr_exclusive, int sync, void *key)
+void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
+                       int nr_exclusive, int sync, void *key)
 {
        wait_queue_t *curr, *next;
 
@@ -6009,12 +6031,7 @@ void sched_show_task(struct task_struct *p)
                printk(KERN_CONT " %016lx ", thread_saved_pc(p));
 #endif
 #ifdef CONFIG_DEBUG_STACK_USAGE
-       {
-               unsigned long *n = end_of_stack(p);
-               while (!*n)
-                       n++;
-               free = (unsigned long)n - (unsigned long)end_of_stack(p);
-       }
+       free = stack_not_used(p);
 #endif
        printk(KERN_CONT "%5lu %5d %6d\n", free,
                task_pid_nr(p), task_pid_nr(p->real_parent));
@@ -7009,20 +7026,26 @@ static void free_rootdomain(struct root_domain *rd)
 
 static void rq_attach_root(struct rq *rq, struct root_domain *rd)
 {
+       struct root_domain *old_rd = NULL;
        unsigned long flags;
 
        spin_lock_irqsave(&rq->lock, flags);
 
        if (rq->rd) {
-               struct root_domain *old_rd = rq->rd;
+               old_rd = rq->rd;
 
                if (cpumask_test_cpu(rq->cpu, old_rd->online))
                        set_rq_offline(rq);
 
                cpumask_clear_cpu(rq->cpu, old_rd->span);
 
-               if (atomic_dec_and_test(&old_rd->refcount))
-                       free_rootdomain(old_rd);
+               /*
+                * If we dont want to free the old_rt yet then
+                * set old_rd to NULL to skip the freeing later
+                * in this function:
+                */
+               if (!atomic_dec_and_test(&old_rd->refcount))
+                       old_rd = NULL;
        }
 
        atomic_inc(&rd->refcount);
@@ -7033,6 +7056,9 @@ static void rq_attach_root(struct rq *rq, struct root_domain *rd)
                set_rq_online(rq);
 
        spin_unlock_irqrestore(&rq->lock, flags);
+
+       if (old_rd)
+               free_rootdomain(old_rd);
 }
 
 static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
@@ -9280,6 +9306,16 @@ static int sched_rt_global_constraints(void)
 
        return ret;
 }
+
+int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
+{
+       /* Don't accept realtime tasks when there is no way for them to run */
+       if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
+               return 0;
+
+       return 1;
+}
+
 #else /* !CONFIG_RT_GROUP_SCHED */
 static int sched_rt_global_constraints(void)
 {
@@ -9373,8 +9409,7 @@ cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
                      struct task_struct *tsk)
 {
 #ifdef CONFIG_RT_GROUP_SCHED
-       /* Don't accept realtime tasks when there is no way for them to run */
-       if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
+       if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
                return -EINVAL;
 #else
        /* We don't support RT-tasks being in separate groups */