Added a listener mechanism to the scheduler (ATM only for scheduler_simple).

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30242 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/kscheduler.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008, Ingo Weinhold, [email protected].
+ * Copyright 2008-2009, Ingo Weinhold, [email protected].
  * Copyright 2005, Axel Dörfler, [email protected].
  * Distributed under the terms of the MIT License.
  */
@@ -12,6 +12,28 @@
 
 struct scheduling_analysis;
 struct thread;
+struct SchedulerListener;
+
+
+#ifdef __cplusplus
+
+#include <util/DoublyLinkedList.h>
+
+struct SchedulerListener : DoublyLinkedListLinkImpl<SchedulerListener> {
+	virtual						~SchedulerListener();
+
+	virtual	void				ThreadEnqueuedInRunQueue(
+									struct thread* thread) = 0;
+	virtual	void				ThreadRemovedFromRunQueue(
+									struct thread* thread) = 0;
+	virtual	void				ThreadScheduled(struct thread* oldThread,
+									struct thread* newThread) = 0;
+};
+
+typedef DoublyLinkedList<SchedulerListener> SchedulerListenerList;
+extern SchedulerListenerList gSchedulerListeners;
+
+#endif	// __cplusplus
 
 
 struct scheduler_ops {
@@ -29,7 +51,7 @@ struct scheduler_ops {
 	// called when a thread structure is freed - freeing up any allocated
 	// mem on the scheduler's part should be done here
 	void (*on_thread_destroy)(struct thread* thread);
-	
+
 	void (*start)(void);
 };
 
@@ -52,6 +74,9 @@ extern struct scheduler_ops* gScheduler;
 extern "C" {
 #endif
 
+void scheduler_add_listener(struct SchedulerListener* listener);
+void scheduler_remove_listener(struct SchedulerListener* listener);
+
 void scheduler_init(void);
 
 status_t _user_analyze_scheduling(bigtime_t from, bigtime_t until, void* buffer,

src/system/kernel/scheduler/scheduler.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright 2008, Ingo Weinhold, [email protected].
+ * Copyright 2008-2009, Ingo Weinhold, [email protected].
  * Distributed under the terms of the MIT License.
  */
 
@@ -16,6 +16,30 @@
 #define SCHEDULER_TYPE 1
 
 struct scheduler_ops* gScheduler;
+SchedulerListenerList gSchedulerListeners;
+
+
+SchedulerListener::~SchedulerListener()
+{
+}
+
+
+/*!	Add the given scheduler listener. Thread lock must be held.
+*/
+void
+scheduler_add_listener(struct SchedulerListener* listener)
+{
+	gSchedulerListeners.Add(listener);
+}
+
+
+/*!	Remove the given scheduler listener. Thread lock must be held.
+*/
+void
+scheduler_remove_listener(struct SchedulerListener* listener)
+{
+	gSchedulerListeners.Remove(listener);
+}
 
 
 void

src/system/kernel/scheduler/scheduler_simple.cpp

@@ -101,6 +101,12 @@ simple_enqueue_in_run_queue(struct thread *thread)
 
 	T(EnqueueThread(thread, prev, curr));
 
+	// notify listeners
+	for (SchedulerListenerList::Iterator it = gSchedulerListeners.GetIterator();
+			SchedulerListener* listener = it.Next();) {
+		listener->ThreadEnqueuedInRunQueue(thread);
+	}
+
 	thread->queue_next = curr;
 	if (prev)
 		prev->queue_next = thread;
@@ -167,6 +173,12 @@ simple_set_thread_priority(struct thread *thread, int32 priority)
 
 	T(RemoveThread(thread));
 
+	// notify listeners
+	for (SchedulerListenerList::Iterator it = gSchedulerListeners.GetIterator();
+			SchedulerListener* listener = it.Next();) {
+		listener->ThreadRemovedFromRunQueue(thread);
+	}
+
 	// find thread in run queue
 	struct thread *item, *prev;
 	for (item = sRunQueue, prev = NULL; item && item != thread;
@@ -335,6 +347,12 @@ simple_reschedule(void)
 
 	T(ScheduleThread(nextThread, oldThread));
 
+	// notify listeners
+	for (SchedulerListenerList::Iterator it = gSchedulerListeners.GetIterator();
+			SchedulerListener* listener = it.Next();) {
+		listener->ThreadScheduled(oldThread, nextThread);
+	}
+
 	nextThread->state = B_THREAD_RUNNING;
 	nextThread->next_state = B_THREAD_READY;
 	oldThread->was_yielded = false;