usermodehelper: cleanup/fix __orderly_poweroff() && argv_free()

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

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 053dfd7..2b52431 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1979,11 +1979,10 @@ context_switch(struct rq *rq, struct task_struct *prev,
 }
 
 /*
- * nr_running, nr_uninterruptible and nr_context_switches:
+ * nr_running and nr_context_switches:
  *
  * externally visible scheduler statistics: current number of runnable
- * threads, current number of uninterruptible-sleeping threads, total
- * number of context switches performed since bootup.
+ * threads, total number of context switches performed since bootup.
  */
 unsigned long nr_running(void)
 {
@@ -1995,23 +1994,6 @@ unsigned long nr_running(void)
        return sum;
 }
 
-unsigned long nr_uninterruptible(void)
-{
-       unsigned long i, sum = 0;
-
-       for_each_possible_cpu(i)
-               sum += cpu_rq(i)->nr_uninterruptible;
-
-       /*
-        * Since we read the counters lockless, it might be slightly
-        * inaccurate. Do not allow it to go below zero though:
-        */
-       if (unlikely((long)sum < 0))
-               sum = 0;
-
-       return sum;
-}
-
 unsigned long long nr_context_switches(void)
 {
        int i;
@@ -2796,7 +2778,7 @@ static noinline void __schedule_bug(struct task_struct *prev)
        if (irqs_disabled())
                print_irqtrace_events(prev);
        dump_stack();
-       add_taint(TAINT_WARN);
+       add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
 }
 
 /*
@@ -4374,7 +4356,10 @@ EXPORT_SYMBOL(yield);
  * It's the caller's job to ensure that the target task struct
  * can't go away on us before we can do any checks.
  *
- * Returns true if we indeed boosted the target task.
+ * Returns:
+ *     true (>0) if we indeed boosted the target task.
+ *     false (0) if we failed to boost the target.
+ *     -ESRCH if there's no task to yield to.
  */
 bool __sched yield_to(struct task_struct *p, bool preempt)
 {
@@ -4388,6 +4373,15 @@ bool __sched yield_to(struct task_struct *p, bool preempt)
 
 again:
        p_rq = task_rq(p);
+       /*
+        * If we're the only runnable task on the rq and target rq also
+        * has only one task, there's absolutely no point in yielding.
+        */
+       if (rq->nr_running == 1 && p_rq->nr_running == 1) {
+               yielded = -ESRCH;
+               goto out_irq;
+       }
+
        double_rq_lock(rq, p_rq);
        while (task_rq(p) != p_rq) {
                double_rq_unlock(rq, p_rq);
@@ -4395,13 +4389,13 @@ again:
        }
 
        if (!curr->sched_class->yield_to_task)
-               goto out;
+               goto out_unlock;
 
        if (curr->sched_class != p->sched_class)
-               goto out;
+               goto out_unlock;
 
        if (task_running(p_rq, p) || p->state)
-               goto out;
+               goto out_unlock;
 
        yielded = curr->sched_class->yield_to_task(rq, p, preempt);
        if (yielded) {
@@ -4414,11 +4408,12 @@ again:
                        resched_task(p_rq->curr);
        }
 
-out:
+out_unlock:
        double_rq_unlock(rq, p_rq);
+out_irq:
        local_irq_restore(flags);
 
-       if (yielded)
+       if (yielded > 0)
                schedule();
 
        return yielded;