[Click] NotifierQueue on multi-threaded Click problem.

[Joonwoo Park]

Unfortunately, A few hours ago I found that my test machine has gone
into hibernation.
It had worked for about 3 ~ 4 days maybe.
And I found that I can reproduce the problem in short time with
SLEEPINESS_TRIGGER=1.
IMHO, I think process_pending() still has problem.
When another thread's Task::add_pending see 'if (!_pending_nextptr)'
as FALSE, at the same time if we set it to 0, thread->add_pending()
cannot be called again (only if _pending_reschedule is FALSE).
As a result, It's seems that a routerthread go sleep forever.
I tried patch and It works fine although SLEEPINESS_TRIGGER=1. (I have
never seen before working SLEEPINESS_TRIGGER=1)
How about this?

-
Signed-off-by: Joonwoo Park <joonwpark81 at gmail.com>

 lib/master.cc |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/lib/master.cc b/lib/master.cc
index 5a56371..cef62be 100644
--- a/lib/master.cc
+++ b/lib/master.cc
@@ -370,7 +370,15 @@ Master::process_pending(RouterThread *thread)
     // process the list
     while (Task *t = Task::pending_to_task(my_pending)) {
 	my_pending = t->_pending_nextptr;
+	// when another thread's Task::add_pending see 'if (!_pending_nextptr)'
+	// as FALSE, at the same time if we set it to 0, thread->add_pending()
+	// cannot be called again (only if _pending_reschedule is 0).
+	bool lock = !t->_pending_reschedule;
+	if (lock)
+		flags = _task_lock.acquire();
 	t->_pending_nextptr = 0;
+	if (lock)
+		_task_lock.release(flags);
 	t->process_pending(thread);
     }
 }
-

Joonwoo Park