X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FRaiseAsync.c;h=74e9dba635147e47ed8445c72c229583538cf6b4;hb=ce76b92f22b677fd6d978751be811d34fa141c84;hp=d411c4110142f4a8550379ab10ad32c50a5c8d2d;hpb=45c92e91085250724bfc350ae8e78cfe93515235;p=ghc-hetmet.git

diff --git a/rts/RaiseAsync.c b/rts/RaiseAsync.c
index d411c41..74e9dba 100644
--- a/rts/RaiseAsync.c
+++ b/rts/RaiseAsync.c
@@ -575,161 +575,15 @@ performBlockedException (Capability *cap, StgTSO *source, StgTSO *target)
 
    This is for use when we raise an exception in another thread, which
    may be blocked.
-   This has nothing to do with the UnblockThread event in GranSim. -- HWL
-   -------------------------------------------------------------------------- */
-
-#if defined(GRAN) || defined(PARALLEL_HASKELL)
-/*
-  NB: only the type of the blocking queue is different in GranSim and GUM
-      the operations on the queue-elements are the same
-      long live polymorphism!
-
-  Locks: sched_mutex is held upon entry and exit.
-
-*/
-static void
-removeFromQueues(Capability *cap, StgTSO *tso)
-{
-  StgBlockingQueueElement *t, **last;
-
-  switch (tso->why_blocked) {
-
-  case NotBlocked:
-    return;  /* not blocked */
-
-  case BlockedOnSTM:
-    // Be careful: nothing to do here!  We tell the scheduler that the thread
-    // is runnable and we leave it to the stack-walking code to abort the 
-    // transaction while unwinding the stack.  We should perhaps have a debugging
-    // test to make sure that this really happens and that the 'zombie' transaction
-    // does not get committed.
-    goto done;
-
-  case BlockedOnMVar:
-    ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
-    {
-      StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
-      StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
-
-      last = (StgBlockingQueueElement **)&mvar->head;
-      for (t = (StgBlockingQueueElement *)mvar->head; 
-	   t != END_BQ_QUEUE; 
-	   last = &t->link, last_tso = t, t = t->link) {
-	if (t == (StgBlockingQueueElement *)tso) {
-	  *last = (StgBlockingQueueElement *)tso->link;
-	  if (mvar->tail == tso) {
-	    mvar->tail = (StgTSO *)last_tso;
-	  }
-	  goto done;
-	}
-      }
-      barf("removeFromQueues (MVAR): TSO not found");
-    }
 
-  case BlockedOnBlackHole:
-    ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
-    {
-      StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
-
-      last = &bq->blocking_queue;
-      for (t = bq->blocking_queue; 
-	   t != END_BQ_QUEUE; 
-	   last = &t->link, t = t->link) {
-	if (t == (StgBlockingQueueElement *)tso) {
-	  *last = (StgBlockingQueueElement *)tso->link;
-	  goto done;
-	}
-      }
-      barf("removeFromQueues (BLACKHOLE): TSO not found");
-    }
-
-  case BlockedOnException:
-    {
-      StgTSO *target  = tso->block_info.tso;
-
-      ASSERT(get_itbl(target)->type == TSO);
-
-      while (target->what_next == ThreadRelocated) {
-	  target = target2->link;
-	  ASSERT(get_itbl(target)->type == TSO);
-      }
+   Precondition: we have exclusive access to the TSO, which entails
+   holding a lock on the object that owns the queue, if the TSO is
+   blocked.  e.g. if the thread is blocked on an MVar, we must hold a
+   lock on the MVar before calling removeFromQueues().
 
-      last = (StgBlockingQueueElement **)&target->blocked_exceptions;
-      for (t = (StgBlockingQueueElement *)target->blocked_exceptions; 
-	   t != END_BQ_QUEUE; 
-	   last = &t->link, t = t->link) {
-	ASSERT(get_itbl(t)->type == TSO);
-	if (t == (StgBlockingQueueElement *)tso) {
-	  *last = (StgBlockingQueueElement *)tso->link;
-	  goto done;
-	}
-      }
-      barf("removeFromQueues (Exception): TSO not found");
-    }
-
-  case BlockedOnRead:
-  case BlockedOnWrite:
-#if defined(mingw32_HOST_OS)
-  case BlockedOnDoProc:
-#endif
-    {
-      /* take TSO off blocked_queue */
-      StgBlockingQueueElement *prev = NULL;
-      for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE; 
-	   prev = t, t = t->link) {
-	if (t == (StgBlockingQueueElement *)tso) {
-	  if (prev == NULL) {
-	    blocked_queue_hd = (StgTSO *)t->link;
-	    if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
-	      blocked_queue_tl = END_TSO_QUEUE;
-	    }
-	  } else {
-	    prev->link = t->link;
-	    if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
-	      blocked_queue_tl = (StgTSO *)prev;
-	    }
-	  }
-#if defined(mingw32_HOST_OS)
-	  /* (Cooperatively) signal that the worker thread should abort
-	   * the request.
-	   */
-	  abandonWorkRequest(tso->block_info.async_result->reqID);
-#endif
-	  goto done;
-	}
-      }
-      barf("removeFromQueues (I/O): TSO not found");
-    }
-
-  case BlockedOnDelay:
-    {
-      /* take TSO off sleeping_queue */
-      StgBlockingQueueElement *prev = NULL;
-      for (t = (StgBlockingQueueElement *)sleeping_queue; t != END_BQ_QUEUE; 
-	   prev = t, t = t->link) {
-	if (t == (StgBlockingQueueElement *)tso) {
-	  if (prev == NULL) {
-	    sleeping_queue = (StgTSO *)t->link;
-	  } else {
-	    prev->link = t->link;
-	  }
-	  goto done;
-	}
-      }
-      barf("removeFromQueues (delay): TSO not found");
-    }
-
-  default:
-    barf("removeFromQueues: %d", tso->why_blocked);
-  }
+   This has nothing to do with the UnblockThread event in GranSim. -- HWL
+   -------------------------------------------------------------------------- */
 
- done:
-  tso->link = END_TSO_QUEUE;
-  tso->why_blocked = NotBlocked;
-  tso->block_info.closure = NULL;
-  pushOnRunQueue(cap,tso);
-}
-#else
 static void
 removeFromQueues(Capability *cap, StgTSO *tso)
 {
@@ -752,6 +606,9 @@ removeFromQueues(Capability *cap, StgTSO *tso)
       goto done;
 
   case BlockedOnBlackHole:
+      // we have exclusive access to this TSO, which implies that we
+      // must hold sched_mutex:
+      ASSERT_LOCK_HELD(&sched_mutex);
       removeThreadFromQueue(cap, &blackhole_queue, tso);
       goto done;
 
@@ -808,7 +665,6 @@ removeFromQueues(Capability *cap, StgTSO *tso)
   }
   tso->cap = cap;
 }
-#endif
 
 /* -----------------------------------------------------------------------------
  * raiseAsync()