ftrace: fix wakeups
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/sched.c b/kernel/sched.c
index 673b588..9ca4a2e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -642,6 +642,24 @@
# define const_debug static const
#endif
+/**
+ * runqueue_is_locked
+ *
+ * Returns true if the current cpu runqueue is locked.
+ * This interface allows printk to be called with the runqueue lock
+ * held and know whether or not it is OK to wake up the klogd.
+ */
+int runqueue_is_locked(void)
+{
+ int cpu = get_cpu();
+ struct rq *rq = cpu_rq(cpu);
+ int ret;
+
+ ret = spin_is_locked(&rq->lock);
+ put_cpu();
+ return ret;
+}
+
/*
* Debugging: various feature bits
*/
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 65173b1..2ca9d66 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -70,12 +70,13 @@
unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
-/*
- * FIXME: where should this be called?
- */
void trace_wake_up(void)
{
- if (!(trace_flags & TRACE_ITER_BLOCK))
+ /*
+ * The runqueue_is_locked() can fail, but this is the best we
+ * have for now:
+ */
+ if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
wake_up(&trace_wait);
}
@@ -657,6 +658,8 @@
entry->fn.ip = ip;
entry->fn.parent_ip = parent_ip;
spin_unlock_irqrestore(&data->lock, irq_flags);
+
+ trace_wake_up();
}
void
@@ -686,6 +689,8 @@
entry->special.arg2 = arg2;
entry->special.arg3 = arg3;
spin_unlock_irqrestore(&data->lock, irq_flags);
+
+ trace_wake_up();
}
#endif
@@ -759,6 +764,8 @@
entry->ctx.next_prio = wakee->prio;
__trace_stack(tr, data, flags, 5);
spin_unlock_irqrestore(&data->lock, irq_flags);
+
+ trace_wake_up();
}
#ifdef CONFIG_FTRACE