-#include <stdlib.h>
-
-#include "libthreads.h"
+#include "threads.h"
#include "schedule.h"
#include "common.h"
#include "model.h"
-struct thread_list_node {
- struct thread *t;
- struct thread_list_node *next;
- int live;
-};
-
-#define NUM_LIST_NODES 32
-
-struct thread_list_node *head, *tail;
-struct thread_list_node nodes[NUM_LIST_NODES];
-struct thread *current;
-
-static void enqueue_thread(struct thread *t)
+/** Constructor */
+Scheduler::Scheduler() :
+ current(NULL)
{
- int i;
- struct thread_list_node *node;
+}
- for (node = nodes, i = 0; node->live && i < NUM_LIST_NODES; i++, node++);
- if (i >= NUM_LIST_NODES) {
- printf("ran out of nodes\n");
- exit(1);
- }
- node->t = t;
- node->next = NULL;
- node->live = 1;
+/**
+ * Add a Thread to the scheduler's ready list.
+ * @param t The Thread to add
+ */
+void Scheduler::add_thread(Thread *t)
+{
+ DEBUG("thread %d\n", t->get_id());
+ readyList.push_back(t);
+}
- if (tail)
- tail->next = node;
+/**
+ * Remove a given Thread from the scheduler.
+ * @param t The Thread to remove
+ */
+void Scheduler::remove_thread(Thread *t)
+{
+ if (current == t)
+ current = NULL;
else
- head = node;
- tail = node;
+ readyList.remove(t);
}
-static struct thread *dequeue_thread(void)
+/**
+ * Force one Thread to wait on another Thread. The "join" Thread should
+ * eventually wake up the waiting Thread via Scheduler::wake.
+ * @param wait The Thread that should wait
+ * @param join The Thread on which we are waiting.
+ */
+void Scheduler::wait(Thread *wait, Thread *join)
{
- struct thread *pop;
+ ASSERT(!join->is_complete());
+ remove_thread(wait);
+ join->push_wait_list(wait);
+ wait->set_state(THREAD_BLOCKED);
+}
- if (!head)
- return NULL;
+/**
+ * Wake a Thread up that was previously waiting (see Scheduler::wait)
+ * @param t The Thread to wake up
+ */
+void Scheduler::wake(Thread *t)
+{
+ add_thread(t);
+ t->set_state(THREAD_READY);
+}
- pop = head->t;
- head->live = 0;
- if (head == tail)
- tail = NULL;
- head = head->next;
+/**
+ * Remove one Thread from the scheduler. This implementation defaults to FIFO,
+ * if a thread is not already provided.
+ *
+ * @param t Thread to run, if chosen by an external entity (e.g.,
+ * ModelChecker). May be NULL to indicate no external choice.
+ * @return The next Thread to run
+ */
+Thread * Scheduler::next_thread(Thread *t)
+{
+ if (t != NULL) {
+ current = t;
+ readyList.remove(t);
+ } else if (readyList.empty()) {
+ t = NULL;
+ } else {
+ t = readyList.front();
+ current = t;
+ readyList.pop_front();
+ }
- /* Set new current thread */
- current = pop;
+ print();
- return pop;
+ return t;
}
-void DefaultScheduler::add_thread(struct thread *t)
+/**
+ * @return The currently-running Thread
+ */
+Thread * Scheduler::get_current_thread() const
{
- DEBUG("thread %d\n", t->id);
- enqueue_thread(t);
+ return current;
}
-struct thread *DefaultScheduler::next_thread(void)
+/**
+ * Print debugging information about the current state of the scheduler. Only
+ * prints something if debugging is enabled.
+ */
+void Scheduler::print() const
{
- return dequeue_thread();
-}
+ if (current)
+ DEBUG("Current thread: %d\n", current->get_id());
+ else
+ DEBUG("No current thread\n");
+ DEBUG("Num. threads in ready list: %zu\n", readyList.size());
-struct thread *DefaultScheduler::get_current_thread(void)
-{
- return current;
+ std::list<Thread *, MyAlloc< Thread * > >::const_iterator it;
+ for (it = readyList.begin(); it != readyList.end(); it++)
+ DEBUG("In ready list: thread %d\n", (*it)->get_id());
}