Add a write barrier to the TSO link field (#1589)

[ghc-hetmet.git] / rts / sm / MarkWeak.c

diff --git a/rts/sm/MarkWeak.c b/rts/sm/MarkWeak.c
index 3faaf0e..9d47cde 100644 (file)
--- a/rts/sm/MarkWeak.c
+++ b/rts/sm/MarkWeak.c
@@ -200,7 +200,7 @@ traverseWeakPtrList(void)
              ASSERT(get_itbl(t)->type == TSO);
              switch (t->what_next) {
              case ThreadRelocated:
-                 next = t->link;
+                 next = t->_link;
                  *prev = next;
                  continue;
              case ThreadKilled:
@@ -258,7 +258,7 @@ traverseWeakPtrList(void)
        */
       { 
          StgTSO **pt;
-         for (pt = &blackhole_queue; *pt != END_TSO_QUEUE; pt = &((*pt)->link)) {
+         for (pt = &blackhole_queue; *pt != END_TSO_QUEUE; pt = &((*pt)->_link)) {
              *pt = (StgTSO *)isAlive((StgClosure *)*pt);
              ASSERT(*pt != NULL);
          }
@@ -291,7 +291,7 @@ traverseBlackholeQueue (void)
     flag = rtsFalse;
     prev = NULL;
 
-    for (t = blackhole_queue; t != END_TSO_QUEUE; prev=t, t = t->link) {
+    for (t = blackhole_queue; t != END_TSO_QUEUE; prev=t, t = t->_link) {
         // if the thread is not yet alive...
        if (! (tmp = (StgTSO *)isAlive((StgClosure*)t))) {
             // if the closure it is blocked on is either (a) a
@@ -305,7 +305,9 @@ traverseBlackholeQueue (void)
             }
             tmp = t;
             evacuate((StgClosure **)&tmp);
-            if (prev) prev->link = t;
+            if (prev) prev->_link = t; 
+                 // no write barrier when on the blackhole queue,
+                 // because we traverse the whole queue on every GC.
             flag = rtsTrue;
        }
     }