printk/sched: Introduce special printk_sched() for those awkward moments

[linux-beck.git] / kernel / sched / core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 820f7453fda93534ef0e4980d63997c27a473915..8781cec7c3e61a2554745dca759ae653a7c2b49d 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1284,7 +1284,7 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
         * leave kernel.
         */
        if (p->mm && printk_ratelimit()) {
-               printk(KERN_INFO "process %d (%s) no longer affine to cpu%d\n",
+               printk_sched("process %d (%s) no longer affine to cpu%d\n",
                                task_pid_nr(p), p->comm, cpu);
        }
 
@@ -3227,7 +3227,7 @@ need_resched:
 
 static inline void sched_submit_work(struct task_struct *tsk)
 {
-       if (!tsk->state)
+       if (!tsk->state || tsk_is_pi_blocked(tsk))
                return;
        /*
         * If we are going to sleep and we have plugged IO queued,
@@ -3779,6 +3779,24 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
 
        rq = __task_rq_lock(p);
 
+       /*
+        * Idle task boosting is a nono in general. There is one
+        * exception, when PREEMPT_RT and NOHZ is active:
+        *
+        * The idle task calls get_next_timer_interrupt() and holds
+        * the timer wheel base->lock on the CPU and another CPU wants
+        * to access the timer (probably to cancel it). We can safely
+        * ignore the boosting request, as the idle CPU runs this code
+        * with interrupts disabled and will complete the lock
+        * protected section without being interrupted. So there is no
+        * real need to boost.
+        */
+       if (unlikely(p == rq->idle)) {
+               WARN_ON(p != rq->curr);
+               WARN_ON(p->pi_blocked_on);
+               goto out_unlock;
+       }
+
        trace_sched_pi_setprio(p, prio);
        oldprio = p->prio;
        prev_class = p->sched_class;
@@ -3802,11 +3820,10 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
                enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
 
        check_class_changed(rq, p, prev_class, oldprio);
+out_unlock:
        __task_rq_unlock(rq);
 }
-
 #endif
-
 void set_user_nice(struct task_struct *p, long nice)
 {
        int old_prio, delta, on_rq;
@@ -5393,7 +5410,7 @@ static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
                                      unsigned long action, void *hcpu)
 {
        switch (action & ~CPU_TASKS_FROZEN) {
-       case CPU_ONLINE:
+       case CPU_STARTING:
        case CPU_DOWN_FAILED:
                set_cpu_active((long)hcpu, true);
                return NOTIFY_OK;
@@ -6942,6 +6959,9 @@ void __init sched_init(void)
                rq->online = 0;
                rq->idle_stamp = 0;
                rq->avg_idle = 2*sysctl_sched_migration_cost;
+
+               INIT_LIST_HEAD(&rq->cfs_tasks);
+
                rq_attach_root(rq, &def_root_domain);
 #ifdef CONFIG_NO_HZ
                rq->nohz_flags = 0;