Change the representation of the MVar blocked queue
[ghc-hetmet.git] / rts / sm / Scav.c
index 4fa0a22..ae9e81c 100644 (file)
@@ -36,7 +36,6 @@ static void scavenge_large_bitmap (StgPtr p,
 
 #if defined(THREADED_RTS) && !defined(PARALLEL_GC)
 # define evacuate(a) evacuate1(a)
-# define recordMutableGen_GC(a,b) recordMutableGen(a,b)
 # define scavenge_loop(a) scavenge_loop1(a)
 # define scavenge_block(a) scavenge_block1(a)
 # define scavenge_mutable_list(bd,g) scavenge_mutable_list1(bd,g)
@@ -47,17 +46,6 @@ static void scavenge_large_bitmap (StgPtr p,
    Scavenge a TSO.
    -------------------------------------------------------------------------- */
 
-STATIC_INLINE void
-scavenge_TSO_link (StgTSO *tso)
-{
-    // We don't always chase the link field: TSOs on the blackhole
-    // queue are not automatically alive, so the link field is a
-    // "weak" pointer in that case.
-    if (tso->why_blocked != BlockedOnBlackHole) {
-        evacuate((StgClosure **)&tso->_link);
-    }
-}
-
 static void
 scavengeTSO (StgTSO *tso)
 {
@@ -81,13 +69,9 @@ scavengeTSO (StgTSO *tso)
     saved_eager = gct->eager_promotion;
     gct->eager_promotion = rtsFalse;
 
-    if (   tso->why_blocked == BlockedOnMVar
-       || tso->why_blocked == BlockedOnBlackHole
-       || tso->why_blocked == BlockedOnException
-       ) {
-       evacuate(&tso->block_info.closure);
-    }
+
     evacuate((StgClosure **)&tso->blocked_exceptions);
+    evacuate((StgClosure **)&tso->bq);
     
     // scavange current transaction record
     evacuate((StgClosure **)&tso->trec);
@@ -95,20 +79,108 @@ scavengeTSO (StgTSO *tso)
     // scavenge this thread's stack 
     scavenge_stack(tso->sp, &(tso->stack[tso->stack_size]));
 
-    if (gct->failed_to_evac) {
-        tso->dirty = 1;
-        scavenge_TSO_link(tso);
+    tso->dirty = gct->failed_to_evac;
+
+    evacuate((StgClosure **)&tso->_link);
+    if (   tso->why_blocked == BlockedOnMVar
+       || tso->why_blocked == BlockedOnBlackHole
+       || tso->why_blocked == BlockedOnMsgThrowTo
+        || tso->why_blocked == NotBlocked
+       ) {
+       evacuate(&tso->block_info.closure);
+    }
+#ifdef THREADED_RTS
+    // in the THREADED_RTS, block_info.closure must always point to a
+    // valid closure, because we assume this in throwTo().  In the
+    // non-threaded RTS it might be a FD (for
+    // BlockedOnRead/BlockedOnWrite) or a time value (BlockedOnDelay)
+    else {
+        tso->block_info.closure = (StgClosure *)END_TSO_QUEUE;
+    }
+#endif
+
+    if (tso->dirty == 0 && gct->failed_to_evac) {
+        tso->flags |= TSO_LINK_DIRTY;
     } else {
-        tso->dirty = 0;
-        scavenge_TSO_link(tso);
+        tso->flags &= ~TSO_LINK_DIRTY;
+    }
+
+    gct->eager_promotion = saved_eager;
+}
+
+/* -----------------------------------------------------------------------------
+   Mutable arrays of pointers
+   -------------------------------------------------------------------------- */
+
+static StgPtr scavenge_mut_arr_ptrs (StgMutArrPtrs *a)
+{
+    lnat m;
+    rtsBool any_failed;
+    StgPtr p, q;
+
+    any_failed = rtsFalse;
+    p = (StgPtr)&a->payload[0];
+    for (m = 0; (int)m < (int)mutArrPtrsCards(a->ptrs) - 1; m++)
+    {
+        q = p + (1 << MUT_ARR_PTRS_CARD_BITS);
+        for (; p < q; p++) {
+            evacuate((StgClosure**)p);
+        }
         if (gct->failed_to_evac) {
-            tso->flags |= TSO_LINK_DIRTY;
+            any_failed = rtsTrue;
+            *mutArrPtrsCard(a,m) = 1;
+            gct->failed_to_evac = rtsFalse;
         } else {
-            tso->flags &= ~TSO_LINK_DIRTY;
+            *mutArrPtrsCard(a,m) = 0;
         }
     }
 
-    gct->eager_promotion = saved_eager;
+    q = (StgPtr)&a->payload[a->ptrs];
+    if (p < q) {
+        for (; p < q; p++) {
+            evacuate((StgClosure**)p);
+        }
+        if (gct->failed_to_evac) {
+            any_failed = rtsTrue;
+            *mutArrPtrsCard(a,m) = 1;
+            gct->failed_to_evac = rtsFalse;
+        } else {
+            *mutArrPtrsCard(a,m) = 0;
+        }
+    }
+
+    gct->failed_to_evac = any_failed;
+    return (StgPtr)a + mut_arr_ptrs_sizeW(a);
+}
+    
+// scavenge only the marked areas of a MUT_ARR_PTRS
+static StgPtr scavenge_mut_arr_ptrs_marked (StgMutArrPtrs *a)
+{
+    lnat m;
+    StgPtr p, q;
+    rtsBool any_failed;
+
+    any_failed = rtsFalse;
+    for (m = 0; m < mutArrPtrsCards(a->ptrs); m++)
+    {
+        if (*mutArrPtrsCard(a,m) != 0) {
+            p = (StgPtr)&a->payload[m << MUT_ARR_PTRS_CARD_BITS];
+            q = stg_min(p + (1 << MUT_ARR_PTRS_CARD_BITS),
+                        (StgPtr)&a->payload[a->ptrs]);
+            for (; p < q; p++) {
+                evacuate((StgClosure**)p);
+            }
+            if (gct->failed_to_evac) {
+                any_failed = rtsTrue;
+                gct->failed_to_evac = rtsFalse;
+            } else {
+                *mutArrPtrsCard(a,m) = 0;
+            }
+        }
+    }
+
+    gct->failed_to_evac = any_failed;
+    return (StgPtr)a + mut_arr_ptrs_sizeW(a);
 }
 
 /* -----------------------------------------------------------------------------
@@ -320,7 +392,6 @@ scavenge_block (bdescr *bd)
 {
   StgPtr p, q;
   StgInfoTable *info;
-  generation *saved_evac_gen;
   rtsBool saved_eager_promotion;
   gen_workspace *ws;
 
@@ -329,7 +400,6 @@ scavenge_block (bdescr *bd)
 
   gct->scan_bd = bd;
   gct->evac_gen = bd->gen;
-  saved_evac_gen = gct->evac_gen;
   saved_eager_promotion = gct->eager_promotion;
   gct->failed_to_evac = rtsFalse;
 
@@ -458,7 +528,7 @@ scavenge_block (bdescr *bd)
     gen_obj:
     case CONSTR:
     case WEAK:
-    case STABLE_NAME:
+    case PRIM:
     {
        StgPtr end;
 
@@ -497,6 +567,7 @@ scavenge_block (bdescr *bd)
       }
        // fall through 
     case IND_OLDGEN_PERM:
+    case BLACKHOLE:
        evacuate(&((StgInd *)p)->indirectee);
        p += sizeofW(StgInd);
        break;
@@ -515,10 +586,25 @@ scavenge_block (bdescr *bd)
        p += sizeofW(StgMutVar);
        break;
 
-    case CAF_BLACKHOLE:
-    case BLACKHOLE:
-       p += BLACKHOLE_sizeW();
-       break;
+    case BLOCKING_QUEUE:
+    {
+        StgBlockingQueue *bq = (StgBlockingQueue *)p;
+        
+       gct->eager_promotion = rtsFalse;
+        evacuate(&bq->bh);
+        evacuate((StgClosure**)&bq->owner);
+        evacuate((StgClosure**)&bq->queue);
+        evacuate((StgClosure**)&bq->link);
+       gct->eager_promotion = saved_eager_promotion;
+
+       if (gct->failed_to_evac) {
+           bq->header.info = &stg_BLOCKING_QUEUE_DIRTY_info;
+       } else {
+           bq->header.info = &stg_BLOCKING_QUEUE_CLEAN_info;
+       }
+        p += sizeofW(StgBlockingQueue);
+        break;
+    }
 
     case THUNK_SELECTOR:
     { 
@@ -554,20 +640,14 @@ scavenge_block (bdescr *bd)
 
     case MUT_ARR_PTRS_CLEAN:
     case MUT_ARR_PTRS_DIRTY:
-       // follow everything 
     {
-       StgPtr next;
+        // We don't eagerly promote objects pointed to by a mutable
+        // array, but if we find the array only points to objects in
+        // the same or an older generation, we mark it "clean" and
+        // avoid traversing it during minor GCs.
+        gct->eager_promotion = rtsFalse;
 
-       // We don't eagerly promote objects pointed to by a mutable
-       // array, but if we find the array only points to objects in
-       // the same or an older generation, we mark it "clean" and
-       // avoid traversing it during minor GCs.
-       gct->eager_promotion = rtsFalse;
-       next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
-       for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
-           evacuate((StgClosure **)p);
-       }
-       gct->eager_promotion = saved_eager_promotion;
+        p = scavenge_mut_arr_ptrs((StgMutArrPtrs*)p);
 
        if (gct->failed_to_evac) {
            ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_DIRTY_info;
@@ -575,6 +655,7 @@ scavenge_block (bdescr *bd)
            ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_CLEAN_info;
        }
 
+       gct->eager_promotion = saved_eager_promotion;
        gct->failed_to_evac = rtsTrue; // always put it on the mutable list.
        break;
     }
@@ -583,17 +664,12 @@ scavenge_block (bdescr *bd)
     case MUT_ARR_PTRS_FROZEN0:
        // follow everything 
     {
-       StgPtr next;
-
-       next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
-       for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
-           evacuate((StgClosure **)p);
-       }
+        p = scavenge_mut_arr_ptrs((StgMutArrPtrs*)p);
 
        // If we're going to put this object on the mutable list, then
        // set its info ptr to MUT_ARR_PTRS_FROZEN0 to indicate that.
        if (gct->failed_to_evac) {
-           ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
+            ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
        } else {
            ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN_info;
        }
@@ -608,42 +684,21 @@ scavenge_block (bdescr *bd)
        break;
     }
 
-    case TVAR_WATCH_QUEUE:
+    case MUT_PRIM:
       {
-       StgTVarWatchQueue *wq = ((StgTVarWatchQueue *) p);
-       gct->evac_gen = 0;
-       evacuate((StgClosure **)&wq->closure);
-       evacuate((StgClosure **)&wq->next_queue_entry);
-       evacuate((StgClosure **)&wq->prev_queue_entry);
-       gct->evac_gen = saved_evac_gen;
-       gct->failed_to_evac = rtsTrue; // mutable
-       p += sizeofW(StgTVarWatchQueue);
-       break;
-      }
+       StgPtr end;
 
-    case TVAR:
-      {
-       StgTVar *tvar = ((StgTVar *) p);
-       gct->evac_gen = 0;
-       evacuate((StgClosure **)&tvar->current_value);
-       evacuate((StgClosure **)&tvar->first_watch_queue_entry);
-       gct->evac_gen = saved_evac_gen;
-       gct->failed_to_evac = rtsTrue; // mutable
-       p += sizeofW(StgTVar);
-       break;
-      }
+       gct->eager_promotion = rtsFalse;
 
-    case TREC_HEADER:
-      {
-        StgTRecHeader *trec = ((StgTRecHeader *) p);
-        gct->evac_gen = 0;
-       evacuate((StgClosure **)&trec->enclosing_trec);
-       evacuate((StgClosure **)&trec->current_chunk);
-       evacuate((StgClosure **)&trec->invariants_to_check);
-       gct->evac_gen = saved_evac_gen;
+       end = (P_)((StgClosure *)p)->payload + info->layout.payload.ptrs;
+       for (p = (P_)((StgClosure *)p)->payload; p < end; p++) {
+           evacuate((StgClosure **)p);
+       }
+       p += info->layout.payload.nptrs;
+
+       gct->eager_promotion = saved_eager_promotion;
        gct->failed_to_evac = rtsTrue; // mutable
-       p += sizeofW(StgTRecHeader);
-        break;
+       break;
       }
 
     case TREC_CHUNK:
@@ -651,44 +706,19 @@ scavenge_block (bdescr *bd)
        StgWord i;
        StgTRecChunk *tc = ((StgTRecChunk *) p);
        TRecEntry *e = &(tc -> entries[0]);
-       gct->evac_gen = 0;
+       gct->eager_promotion = rtsFalse;
        evacuate((StgClosure **)&tc->prev_chunk);
        for (i = 0; i < tc -> next_entry_idx; i ++, e++ ) {
          evacuate((StgClosure **)&e->tvar);
          evacuate((StgClosure **)&e->expected_value);
          evacuate((StgClosure **)&e->new_value);
        }
-       gct->evac_gen = saved_evac_gen;
+       gct->eager_promotion = saved_eager_promotion;
        gct->failed_to_evac = rtsTrue; // mutable
        p += sizeofW(StgTRecChunk);
        break;
       }
 
-    case ATOMIC_INVARIANT:
-      {
-        StgAtomicInvariant *invariant = ((StgAtomicInvariant *) p);
-        gct->evac_gen = 0;
-       evacuate(&invariant->code);
-       evacuate((StgClosure **)&invariant->last_execution);
-       gct->evac_gen = saved_evac_gen;
-       gct->failed_to_evac = rtsTrue; // mutable
-       p += sizeofW(StgAtomicInvariant);
-        break;
-      }
-
-    case INVARIANT_CHECK_QUEUE:
-      {
-        StgInvariantCheckQueue *queue = ((StgInvariantCheckQueue *) p);
-        gct->evac_gen = 0;
-       evacuate((StgClosure **)&queue->invariant);
-       evacuate((StgClosure **)&queue->my_execution);
-       evacuate((StgClosure **)&queue->next_queue_entry);
-       gct->evac_gen = saved_evac_gen;
-       gct->failed_to_evac = rtsTrue; // mutable
-       p += sizeofW(StgInvariantCheckQueue);
-        break;
-      }
-
     default:
        barf("scavenge: unimplemented/strange closure type %d @ %p", 
             info->type, p);
@@ -742,10 +772,10 @@ scavenge_mark_stack(void)
 {
     StgPtr p, q;
     StgInfoTable *info;
-    generation *saved_evac_gen;
+    rtsBool saved_eager_promotion;
 
     gct->evac_gen = oldest_gen;
-    saved_evac_gen = gct->evac_gen;
+    saved_eager_promotion = gct->eager_promotion;
 
     while ((p = pop_mark_stack())) {
 
@@ -758,8 +788,6 @@ scavenge_mark_stack(void)
         case MVAR_CLEAN:
         case MVAR_DIRTY:
         { 
-            rtsBool saved_eager_promotion = gct->eager_promotion;
-            
             StgMVar *mvar = ((StgMVar *)p);
             gct->eager_promotion = rtsFalse;
             evacuate((StgClosure **)&mvar->head);
@@ -842,7 +870,7 @@ scavenge_mark_stack(void)
        gen_obj:
        case CONSTR:
        case WEAK:
-       case STABLE_NAME:
+       case PRIM:
        {
            StgPtr end;
            
@@ -867,15 +895,15 @@ scavenge_mark_stack(void)
            // no "old" generation.
            break;
 
+       case IND:
        case IND_OLDGEN:
        case IND_OLDGEN_PERM:
+        case BLACKHOLE:
            evacuate(&((StgInd *)p)->indirectee);
            break;
 
        case MUT_VAR_CLEAN:
        case MUT_VAR_DIRTY: {
-           rtsBool saved_eager_promotion = gct->eager_promotion;
-           
            gct->eager_promotion = rtsFalse;
            evacuate(&((StgMutVar *)p)->var);
            gct->eager_promotion = saved_eager_promotion;
@@ -888,8 +916,25 @@ scavenge_mark_stack(void)
            break;
        }
 
-       case CAF_BLACKHOLE:
-       case BLACKHOLE:
+        case BLOCKING_QUEUE:
+        {
+            StgBlockingQueue *bq = (StgBlockingQueue *)p;
+            
+            gct->eager_promotion = rtsFalse;
+            evacuate(&bq->bh);
+            evacuate((StgClosure**)&bq->owner);
+            evacuate((StgClosure**)&bq->queue);
+            evacuate((StgClosure**)&bq->link);
+            gct->eager_promotion = saved_eager_promotion;
+            
+            if (gct->failed_to_evac) {
+                bq->header.info = &stg_BLOCKING_QUEUE_DIRTY_info;
+            } else {
+                bq->header.info = &stg_BLOCKING_QUEUE_CLEAN_info;
+            }
+            break;
+        }
+
        case ARR_WORDS:
            break;
 
@@ -922,27 +967,21 @@ scavenge_mark_stack(void)
        case MUT_ARR_PTRS_DIRTY:
            // follow everything 
        {
-           StgPtr next;
-           rtsBool saved_eager;
-
            // We don't eagerly promote objects pointed to by a mutable
            // array, but if we find the array only points to objects in
            // the same or an older generation, we mark it "clean" and
            // avoid traversing it during minor GCs.
-           saved_eager = gct->eager_promotion;
            gct->eager_promotion = rtsFalse;
-           next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
-           for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
-               evacuate((StgClosure **)p);
-           }
-           gct->eager_promotion = saved_eager;
 
-           if (gct->failed_to_evac) {
-               ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_DIRTY_info;
-           } else {
-               ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_CLEAN_info;
-           }
+            scavenge_mut_arr_ptrs((StgMutArrPtrs *)p);
+
+            if (gct->failed_to_evac) {
+                ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_DIRTY_info;
+            } else {
+                ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_CLEAN_info;
+            }
 
+           gct->eager_promotion = saved_eager_promotion;
            gct->failed_to_evac = rtsTrue; // mutable anyhow.
            break;
        }
@@ -951,12 +990,9 @@ scavenge_mark_stack(void)
        case MUT_ARR_PTRS_FROZEN0:
            // follow everything 
        {
-           StgPtr next, q = p;
+           StgPtr q = p;
            
-           next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
-           for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
-               evacuate((StgClosure **)p);
-           }
+            scavenge_mut_arr_ptrs((StgMutArrPtrs *)p);
 
            // If we're going to put this object on the mutable list, then
            // set its info ptr to MUT_ARR_PTRS_FROZEN0 to indicate that.
@@ -974,81 +1010,39 @@ scavenge_mark_stack(void)
            break;
        }
 
-       case TVAR_WATCH_QUEUE:
-         {
-           StgTVarWatchQueue *wq = ((StgTVarWatchQueue *) p);
-           gct->evac_gen = 0;
-            evacuate((StgClosure **)&wq->closure);
-           evacuate((StgClosure **)&wq->next_queue_entry);
-           evacuate((StgClosure **)&wq->prev_queue_entry);
-           gct->evac_gen = saved_evac_gen;
-           gct->failed_to_evac = rtsTrue; // mutable
-           break;
-         }
-         
-       case TVAR:
-         {
-           StgTVar *tvar = ((StgTVar *) p);
-           gct->evac_gen = 0;
-           evacuate((StgClosure **)&tvar->current_value);
-           evacuate((StgClosure **)&tvar->first_watch_queue_entry);
-           gct->evac_gen = saved_evac_gen;
-           gct->failed_to_evac = rtsTrue; // mutable
-           break;
-         }
-         
+        case MUT_PRIM:
+        {
+            StgPtr end;
+            
+            gct->eager_promotion = rtsFalse;
+            
+            end = (P_)((StgClosure *)p)->payload + info->layout.payload.ptrs;
+            for (p = (P_)((StgClosure *)p)->payload; p < end; p++) {
+                evacuate((StgClosure **)p);
+            }
+            
+            gct->eager_promotion = saved_eager_promotion;
+            gct->failed_to_evac = rtsTrue; // mutable
+            break;
+        }
+
        case TREC_CHUNK:
          {
            StgWord i;
            StgTRecChunk *tc = ((StgTRecChunk *) p);
            TRecEntry *e = &(tc -> entries[0]);
-           gct->evac_gen = 0;
+           gct->eager_promotion = rtsFalse;
            evacuate((StgClosure **)&tc->prev_chunk);
            for (i = 0; i < tc -> next_entry_idx; i ++, e++ ) {
              evacuate((StgClosure **)&e->tvar);
              evacuate((StgClosure **)&e->expected_value);
              evacuate((StgClosure **)&e->new_value);
            }
-           gct->evac_gen = saved_evac_gen;
-           gct->failed_to_evac = rtsTrue; // mutable
-           break;
-         }
-
-       case TREC_HEADER:
-         {
-           StgTRecHeader *trec = ((StgTRecHeader *) p);
-           gct->evac_gen = 0;
-           evacuate((StgClosure **)&trec->enclosing_trec);
-           evacuate((StgClosure **)&trec->current_chunk);
-           evacuate((StgClosure **)&trec->invariants_to_check);
-           gct->evac_gen = saved_evac_gen;
+           gct->eager_promotion = saved_eager_promotion;
            gct->failed_to_evac = rtsTrue; // mutable
            break;
          }
 
-        case ATOMIC_INVARIANT:
-          {
-            StgAtomicInvariant *invariant = ((StgAtomicInvariant *) p);
-            gct->evac_gen = 0;
-           evacuate(&invariant->code);
-           evacuate((StgClosure **)&invariant->last_execution);
-           gct->evac_gen = saved_evac_gen;
-           gct->failed_to_evac = rtsTrue; // mutable
-            break;
-          }
-
-        case INVARIANT_CHECK_QUEUE:
-          {
-            StgInvariantCheckQueue *queue = ((StgInvariantCheckQueue *) p);
-            gct->evac_gen = 0;
-           evacuate((StgClosure **)&queue->invariant);
-           evacuate((StgClosure **)&queue->my_execution);
-            evacuate((StgClosure **)&queue->next_queue_entry);
-           gct->evac_gen = saved_evac_gen;
-           gct->failed_to_evac = rtsTrue; // mutable
-            break;
-          }
-
        default:
            barf("scavenge_mark_stack: unimplemented/strange closure type %d @ %p", 
                 info->type, p);
@@ -1075,9 +1069,11 @@ static rtsBool
 scavenge_one(StgPtr p)
 {
     const StgInfoTable *info;
-    generation *saved_evac_gen = gct->evac_gen;
     rtsBool no_luck;
+    rtsBool saved_eager_promotion;
     
+    saved_eager_promotion = gct->eager_promotion;
+
     ASSERT(LOOKS_LIKE_CLOSURE_PTR(p));
     info = get_itbl((StgClosure *)p);
     
@@ -1086,8 +1082,6 @@ scavenge_one(StgPtr p)
     case MVAR_CLEAN:
     case MVAR_DIRTY:
     { 
-       rtsBool saved_eager_promotion = gct->eager_promotion;
-
        StgMVar *mvar = ((StgMVar *)p);
        gct->eager_promotion = rtsFalse;
        evacuate((StgClosure **)&mvar->head);
@@ -1132,6 +1126,7 @@ scavenge_one(StgPtr p)
     case CONSTR_0_2:
     case CONSTR_2_0:
     case WEAK:
+    case PRIM:
     case IND_PERM:
     {
        StgPtr q, end;
@@ -1146,7 +1141,6 @@ scavenge_one(StgPtr p)
     case MUT_VAR_CLEAN:
     case MUT_VAR_DIRTY: {
        StgPtr q = p;
-       rtsBool saved_eager_promotion = gct->eager_promotion;
 
        gct->eager_promotion = rtsFalse;
        evacuate(&((StgMutVar *)p)->var);
@@ -1160,10 +1154,25 @@ scavenge_one(StgPtr p)
        break;
     }
 
-    case CAF_BLACKHOLE:
-    case BLACKHOLE:
-       break;
-       
+    case BLOCKING_QUEUE:
+    {
+        StgBlockingQueue *bq = (StgBlockingQueue *)p;
+        
+        gct->eager_promotion = rtsFalse;
+        evacuate(&bq->bh);
+        evacuate((StgClosure**)&bq->owner);
+        evacuate((StgClosure**)&bq->queue);
+        evacuate((StgClosure**)&bq->link);
+        gct->eager_promotion = saved_eager_promotion;
+        
+        if (gct->failed_to_evac) {
+            bq->header.info = &stg_BLOCKING_QUEUE_DIRTY_info;
+        } else {
+            bq->header.info = &stg_BLOCKING_QUEUE_CLEAN_info;
+        }
+        break;
+    }
+
     case THUNK_SELECTOR:
     { 
        StgSelector *s = (StgSelector *)p;
@@ -1196,28 +1205,21 @@ scavenge_one(StgPtr p)
     case MUT_ARR_PTRS_CLEAN:
     case MUT_ARR_PTRS_DIRTY:
     {
-       StgPtr next, q;
-       rtsBool saved_eager;
-
        // We don't eagerly promote objects pointed to by a mutable
        // array, but if we find the array only points to objects in
        // the same or an older generation, we mark it "clean" and
        // avoid traversing it during minor GCs.
-       saved_eager = gct->eager_promotion;
        gct->eager_promotion = rtsFalse;
-       q = p;
-       next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
-       for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
-           evacuate((StgClosure **)p);
-       }
-       gct->eager_promotion = saved_eager;
+
+        scavenge_mut_arr_ptrs((StgMutArrPtrs *)p);
 
        if (gct->failed_to_evac) {
-           ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_DIRTY_info;
+           ((StgClosure *)p)->header.info = &stg_MUT_ARR_PTRS_DIRTY_info;
        } else {
-           ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_CLEAN_info;
+           ((StgClosure *)p)->header.info = &stg_MUT_ARR_PTRS_CLEAN_info;
        }
 
+       gct->eager_promotion = saved_eager_promotion;
        gct->failed_to_evac = rtsTrue;
        break;
     }
@@ -1226,19 +1228,14 @@ scavenge_one(StgPtr p)
     case MUT_ARR_PTRS_FROZEN0:
     {
        // follow everything 
-       StgPtr next, q=p;
-      
-       next = p + mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
-       for (p = (P_)((StgMutArrPtrs *)p)->payload; p < next; p++) {
-           evacuate((StgClosure **)p);
-       }
-
+        scavenge_mut_arr_ptrs((StgMutArrPtrs *)p);
+        
        // If we're going to put this object on the mutable list, then
        // set its info ptr to MUT_ARR_PTRS_FROZEN0 to indicate that.
        if (gct->failed_to_evac) {
-           ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
+           ((StgClosure *)p)->header.info = &stg_MUT_ARR_PTRS_FROZEN0_info;
        } else {
-           ((StgClosure *)q)->header.info = &stg_MUT_ARR_PTRS_FROZEN_info;
+           ((StgClosure *)p)->header.info = &stg_MUT_ARR_PTRS_FROZEN_info;
        }
        break;
     }
@@ -1249,87 +1246,47 @@ scavenge_one(StgPtr p)
        break;
     }
   
-    case TVAR_WATCH_QUEUE:
-      {
-       StgTVarWatchQueue *wq = ((StgTVarWatchQueue *) p);
-       gct->evac_gen = 0;
-        evacuate((StgClosure **)&wq->closure);
-        evacuate((StgClosure **)&wq->next_queue_entry);
-        evacuate((StgClosure **)&wq->prev_queue_entry);
-       gct->evac_gen = saved_evac_gen;
-       gct->failed_to_evac = rtsTrue; // mutable
-       break;
-      }
+    case MUT_PRIM:
+    {
+       StgPtr end;
+        
+       gct->eager_promotion = rtsFalse;
+        
+       end = (P_)((StgClosure *)p)->payload + info->layout.payload.ptrs;
+       for (p = (P_)((StgClosure *)p)->payload; p < end; p++) {
+           evacuate((StgClosure **)p);
+       }
 
-    case TVAR:
-      {
-       StgTVar *tvar = ((StgTVar *) p);
-       gct->evac_gen = 0;
-       evacuate((StgClosure **)&tvar->current_value);
-        evacuate((StgClosure **)&tvar->first_watch_queue_entry);
-       gct->evac_gen = saved_evac_gen;
+       gct->eager_promotion = saved_eager_promotion;
        gct->failed_to_evac = rtsTrue; // mutable
        break;
-      }
 
-    case TREC_HEADER:
-      {
-        StgTRecHeader *trec = ((StgTRecHeader *) p);
-        gct->evac_gen = 0;
-       evacuate((StgClosure **)&trec->enclosing_trec);
-       evacuate((StgClosure **)&trec->current_chunk);
-        evacuate((StgClosure **)&trec->invariants_to_check);
-       gct->evac_gen = saved_evac_gen;
-       gct->failed_to_evac = rtsTrue; // mutable
-        break;
-      }
+    }
 
     case TREC_CHUNK:
       {
        StgWord i;
        StgTRecChunk *tc = ((StgTRecChunk *) p);
        TRecEntry *e = &(tc -> entries[0]);
-       gct->evac_gen = 0;
+       gct->eager_promotion = rtsFalse;
        evacuate((StgClosure **)&tc->prev_chunk);
        for (i = 0; i < tc -> next_entry_idx; i ++, e++ ) {
          evacuate((StgClosure **)&e->tvar);
          evacuate((StgClosure **)&e->expected_value);
          evacuate((StgClosure **)&e->new_value);
        }
-       gct->evac_gen = saved_evac_gen;
+       gct->eager_promotion = saved_eager_promotion;
        gct->failed_to_evac = rtsTrue; // mutable
        break;
       }
 
-    case ATOMIC_INVARIANT:
-    {
-      StgAtomicInvariant *invariant = ((StgAtomicInvariant *) p);
-      gct->evac_gen = 0;
-      evacuate(&invariant->code);
-      evacuate((StgClosure **)&invariant->last_execution);
-      gct->evac_gen = saved_evac_gen;
-      gct->failed_to_evac = rtsTrue; // mutable
-      break;
-    }
-
-    case INVARIANT_CHECK_QUEUE:
-    {
-      StgInvariantCheckQueue *queue = ((StgInvariantCheckQueue *) p);
-      gct->evac_gen = 0;
-      evacuate((StgClosure **)&queue->invariant);
-      evacuate((StgClosure **)&queue->my_execution);
-      evacuate((StgClosure **)&queue->next_queue_entry);
-      gct->evac_gen = saved_evac_gen;
-      gct->failed_to_evac = rtsTrue; // mutable
-      break;
-    }
-
     case IND:
         // IND can happen, for example, when the interpreter allocates
         // a gigantic AP closure (more than one block), which ends up
         // on the large-object list and then gets updated.  See #3424.
     case IND_OLDGEN:
     case IND_OLDGEN_PERM:
+    case BLACKHOLE:
     case IND_STATIC:
        evacuate(&((StgInd *)p)->indirectee);
 
@@ -1391,7 +1348,7 @@ scavenge_mutable_list(bdescr *bd, generation *gen)
 #ifdef DEBUG       
            switch (get_itbl((StgClosure *)p)->type) {
            case MUT_VAR_CLEAN:
-               barf("MUT_VAR_CLEAN on mutable list");
+                // can happen due to concurrent writeMutVars
            case MUT_VAR_DIRTY:
                mutlist_MUTVARS++; break;
            case MUT_ARR_PTRS_CLEAN:
@@ -1412,21 +1369,49 @@ scavenge_mutable_list(bdescr *bd, generation *gen)
            // definitely doesn't point into a young generation.
            // Clean objects don't need to be scavenged.  Some clean
            // objects (MUT_VAR_CLEAN) are not kept on the mutable
-           // list at all; others, such as MUT_ARR_PTRS_CLEAN
+           // list at all; others, such as TSO
            // are always on the mutable list.
            //
            switch (get_itbl((StgClosure *)p)->type) {
            case MUT_ARR_PTRS_CLEAN:
                recordMutableGen_GC((StgClosure *)p,gen->no);
                continue;
+           case MUT_ARR_PTRS_DIRTY:
+            {
+                rtsBool saved_eager_promotion;
+                saved_eager_promotion = gct->eager_promotion;
+                gct->eager_promotion = rtsFalse;
+
+                scavenge_mut_arr_ptrs_marked((StgMutArrPtrs *)p);
+
+                if (gct->failed_to_evac) {
+                    ((StgClosure *)p)->header.info = &stg_MUT_ARR_PTRS_DIRTY_info;
+                } else {
+                    ((StgClosure *)p)->header.info = &stg_MUT_ARR_PTRS_CLEAN_info;
+                }
+
+                gct->eager_promotion = saved_eager_promotion;
+                gct->failed_to_evac = rtsFalse;
+               recordMutableGen_GC((StgClosure *)p,gen->no);
+               continue;
+            }
            case TSO: {
                StgTSO *tso = (StgTSO *)p;
                if (tso->dirty == 0) {
-                    // Must be on the mutable list because its link
-                    // field is dirty.
-                    ASSERT(tso->flags & TSO_LINK_DIRTY);
-
-                    scavenge_TSO_link(tso);
+                    // Should be on the mutable list because its link
+                    // field is dirty.  However, in parallel GC we may
+                    // have a thread on multiple mutable lists, so
+                    // this assertion would be invalid:
+                    // ASSERT(tso->flags & TSO_LINK_DIRTY);
+
+                    evacuate((StgClosure **)&tso->_link);
+                    if (   tso->why_blocked == BlockedOnMVar
+                        || tso->why_blocked == BlockedOnBlackHole
+                        || tso->why_blocked == BlockedOnMsgThrowTo
+                        || tso->why_blocked == NotBlocked
+                        ) {
+                        evacuate((StgClosure **)&tso->block_info.prev);
+                    }
                     if (gct->failed_to_evac) {
                         recordMutableGen_GC((StgClosure *)p,gen->no);
                         gct->failed_to_evac = rtsFalse;
@@ -1646,10 +1631,12 @@ scavenge_stack(StgPtr p, StgPtr stack_end)
        // before GC, but that seems like overkill.
        //
        // Scavenging this update frame as normal would be disastrous;
-       // the updatee would end up pointing to the value.  So we turn
-       // the indirection into an IND_PERM, so that evacuate will
-       // copy the indirection into the old generation instead of
-       // discarding it.
+       // the updatee would end up pointing to the value.  So we
+       // check whether the value after evacuation is a BLACKHOLE,
+       // and if not, we change the update frame to an stg_enter
+       // frame that simply returns the value.  Hence, blackholing is
+        // compulsory (otherwise we would have to check for thunks
+        // too).
         //
         // Note [upd-black-hole]
         // One slight hiccup is that the THUNK_SELECTOR machinery can
@@ -1660,22 +1647,17 @@ scavenge_stack(StgPtr p, StgPtr stack_end)
         // the updatee is never a THUNK_SELECTOR and we're ok.
         // NB. this is a new invariant: blackholing is not optional.
     {
-        nat type;
-        const StgInfoTable *i;
-        StgClosure *updatee;
-
-        updatee = ((StgUpdateFrame *)p)->updatee;
-        i = updatee->header.info;
-        if (!IS_FORWARDING_PTR(i)) {
-            type = get_itbl(updatee)->type;
-            if (type == IND) {
-                updatee->header.info = &stg_IND_PERM_info;
-            } else if (type == IND_OLDGEN) {
-                updatee->header.info = &stg_IND_OLDGEN_PERM_info;
-            }            
+        StgUpdateFrame *frame = (StgUpdateFrame *)p;
+        StgClosure *v;
+
+        evacuate(&frame->updatee);
+        v = frame->updatee;
+        if (GET_CLOSURE_TAG(v) != 0 ||
+            (get_itbl(v)->type != BLACKHOLE)) {
+            // blackholing is compulsory, see above.
+            frame->header.info = (const StgInfoTable*)&stg_enter_checkbh_info;
         }
-        evacuate(&((StgUpdateFrame *)p)->updatee);
-        ASSERT(GET_CLOSURE_TAG(((StgUpdateFrame *)p)->updatee) == 0);
+        ASSERT(v->header.info != &stg_TSO_info);
         p += sizeofW(StgUpdateFrame);
         continue;
     }