1 files changed, 94 insertions, 0 deletions

diff --git a/tests/threads/priority-donate-nest.c b/tests/threads/priority-donate-nest.c
new file mode 100644
index 0000000..3a3a9a5
--- /dev/null
+++ b/tests/threads/priority-donate-nest.c
@@ -0,0 +1,94 @@
+/* Low-priority main thread L acquires lock A.  Medium-priority
+   thread M then acquires lock B then blocks on acquiring lock A.
+   High-priority thread H then blocks on acquiring lock B.  Thus,
+   thread H donates its priority to M, which in turn donates it
+   to thread L.
+   
+   Based on a test originally submitted for Stanford's CS 140 in
+   winter 1999 by Matt Franklin <startled@leland.stanford.edu>,
+   Greg Hutchins <gmh@leland.stanford.edu>, Yu Ping Hu
+   <yph@cs.stanford.edu>.  Modified by arens. */
+
+#include <stdio.h>
+#include "tests/threads/tests.h"
+#include "threads/init.h"
+#include "threads/synch.h"
+#include "threads/thread.h"
+
+struct locks 
+  {
+    struct lock *a;
+    struct lock *b;
+  };
+
+static thread_func medium_thread_func;
+static thread_func high_thread_func;
+
+void
+test_priority_donate_nest (void) 
+{
+  struct lock a, b;
+  struct locks locks;
+
+  /* This test does not work with the MLFQS. */
+  ASSERT (!thread_mlfqs);
+
+  /* Make sure our priority is the default. */
+  ASSERT (thread_get_priority () == PRI_DEFAULT);
+
+  lock_init (&a);
+  lock_init (&b);
+
+  lock_acquire (&a);
+
+  locks.a = &a;
+  locks.b = &b;
+  thread_create ("medium", PRI_DEFAULT + 1, medium_thread_func, &locks);
+  thread_yield ();
+  msg ("Low thread should have priority %d.  Actual priority: %d.",
+       PRI_DEFAULT + 1, thread_get_priority ());
+
+  thread_create ("high", PRI_DEFAULT + 2, high_thread_func, &b);
+  thread_yield ();
+  msg ("Low thread should have priority %d.  Actual priority: %d.",
+       PRI_DEFAULT + 2, thread_get_priority ());
+
+  lock_release (&a);
+  thread_yield ();
+  msg ("Medium thread should just have finished.");
+  msg ("Low thread should have priority %d.  Actual priority: %d.",
+       PRI_DEFAULT, thread_get_priority ());
+}
+
+static void
+medium_thread_func (void *locks_) 
+{
+  struct locks *locks = locks_;
+
+  lock_acquire (locks->b);
+  lock_acquire (locks->a);
+
+  msg ("Medium thread should have priority %d.  Actual priority: %d.",
+       PRI_DEFAULT + 2, thread_get_priority ());
+  msg ("Medium thread got the lock.");
+
+  lock_release (locks->a);
+  thread_yield ();
+
+  lock_release (locks->b);
+  thread_yield ();
+
+  msg ("High thread should have just finished.");
+  msg ("Middle thread finished.");
+}
+
+static void
+high_thread_func (void *lock_) 
+{
+  struct lock *lock = lock_;
+
+  lock_acquire (lock);
+  msg ("High thread got the lock.");
+  lock_release (lock);
+  msg ("High thread finished.");
+}