X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Ftests%2Fthreads%2Fpriority-donate-nest.c;h=71cf8a9186db979a14ae224ccd809cf2f21754bf;hb=fd36e1fee6a7f98bfbc13aa20f0ee7d3aeab72ef;hp=a7b919c90b276cf049bdab81598687e40a11f4e6;hpb=0b877ed0d174985b620fdf3be1183ac09d7c55fd;p=pintos-anon

diff --git a/src/tests/threads/priority-donate-nest.c b/src/tests/threads/priority-donate-nest.c
index a7b919c..71cf8a9 100644
--- a/src/tests/threads/priority-donate-nest.c
+++ b/src/tests/threads/priority-donate-nest.c
@@ -1,5 +1,9 @@
-/* Problem 1-3: Priority Scheduling tests.
-
+/* 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
@@ -39,15 +43,15 @@ test_priority_donate_nest (void)
 
   locks.a = &a;
   locks.b = &b;
-  thread_create ("medium", PRI_DEFAULT - 1, medium_thread_func, &locks);
+  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 ());
+       PRI_DEFAULT + 1, thread_get_priority ());
 
-  thread_create ("high", PRI_DEFAULT - 2, high_thread_func, &b);
+  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 ());
+       PRI_DEFAULT + 2, thread_get_priority ());
 
   lock_release (&a);
   thread_yield ();
@@ -65,7 +69,7 @@ medium_thread_func (void *locks_)
   lock_acquire (locks->a);
 
   msg ("Medium thread should have priority %d.  Actual priority: %d.",
-       PRI_DEFAULT - 2, thread_get_priority ());
+       PRI_DEFAULT + 2, thread_get_priority ());
   msg ("Medium thread got the lock.");
 
   lock_release (locks->a);