[project @ 2004-05-27 15:21:37 by simonmar]

[ghc-hetmet.git] / ghc / rts / Schedule.c

diff --git a/ghc/rts/Schedule.c b/ghc/rts/Schedule.c
index 262e4c4..f8a6587 100644 (file)
--- a/ghc/rts/Schedule.c
+++ b/ghc/rts/Schedule.c
@@ -1,5 +1,5 @@
 /* ---------------------------------------------------------------------------
- * $Id: Schedule.c,v 1.194 2004/03/13 00:56:45 sof Exp $
+ * $Id: Schedule.c,v 1.198 2004/05/27 15:21:37 simonmar Exp $
  *
  * (c) The GHC Team, 1998-2003
  *
@@ -276,7 +276,10 @@ startSchedulerTaskIfNecessary(void)
       // just because the last one hasn't yet reached the
       // "waiting for capability" state
       startingWorkerThread = rtsTrue;
-      startTask(taskStart);
+      if(!startTask(taskStart))
+      {
+        startingWorkerThread = rtsFalse;
+      }
     }
   }
 }
@@ -894,23 +897,35 @@ run_thread:
     /* Run the current thread 
      */
     prev_what_next = t->what_next;
+
+    errno = t->saved_errno;
+
     switch (prev_what_next) {
+
     case ThreadKilled:
     case ThreadComplete:
        /* Thread already finished, return to scheduler. */
        ret = ThreadFinished;
        break;
+
     case ThreadRunGHC:
-       errno = t->saved_errno;
        ret = StgRun((StgFunPtr) stg_returnToStackTop, &cap->r);
-       t->saved_errno = errno;
        break;
+
     case ThreadInterpret:
        ret = interpretBCO(cap);
        break;
+
     default:
       barf("schedule: invalid what_next field");
     }
+
+    // The TSO might have moved, so find the new location:
+    t = cap->r.rCurrentTSO;
+
+    // And save the current errno in this thread.
+    t->saved_errno = errno;
+
     /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
     
     /* Costs for the scheduler are assigned to CCS_SYSTEM */
@@ -926,7 +941,6 @@ run_thread:
 #elif !defined(GRAN) && !defined(PAR)
     IF_DEBUG(scheduler,fprintf(stderr,"sched: "););
 #endif
-    t = cap->r.rCurrentTSO;
     
 #if defined(PAR)
     /* HACK 675: if the last thread didn't yield, make sure to print a 
@@ -1062,7 +1076,6 @@ run_thread:
        if (t->main != NULL) {
            t->main->tso = new_t;
        }
-       threadPaused(new_t);
        PUSH_ON_RUN_QUEUE(new_t);
       }
       break;
@@ -1473,9 +1486,15 @@ deleteAllThreads ( void )
       next = t->global_link;
       deleteThread(t);
   }      
-  run_queue_hd = run_queue_tl = END_TSO_QUEUE;
-  blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
-  sleeping_queue = END_TSO_QUEUE;
+
+  // The run queue now contains a bunch of ThreadKilled threads.  We
+  // must not throw these away: the main thread(s) will be in there
+  // somewhere, and the main scheduler loop has to deal with it.
+  // Also, the run queue is the only thing keeping these threads from
+  // being GC'd, and we don't want the "main thread has been GC'd" panic.
+
+  ASSERT(blocked_queue_hd == END_TSO_QUEUE);
+  ASSERT(sleeping_queue == END_TSO_QUEUE);
 }
 
 /* startThread and  insertThread are now in GranSim.c -- HWL */