[project @ 2001-10-01 10:52:36 by simonmar]

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

diff --git a/ghc/rts/GC.c b/ghc/rts/GC.c
index 3d4e687..713c579 100644 (file)
--- a/ghc/rts/GC.c
+++ b/ghc/rts/GC.c
@@ -1,5 +1,5 @@
 /* -----------------------------------------------------------------------------
- * $Id: GC.c,v 1.121 2001/08/17 15:46:54 simonmar Exp $
+ * $Id: GC.c,v 1.123 2001/10/01 10:52:36 simonmar Exp $
  *
  * (c) The GHC Team 1998-1999
  *
@@ -741,10 +741,11 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc )
 
       // Auto-enable compaction when the residency reaches a
       // certain percentage of the maximum heap size (default: 30%).
-      if (RtsFlags.GcFlags.compact ||
-         (max > 0 &&
-          oldest_gen->steps[0].n_blocks > 
-          (RtsFlags.GcFlags.compactThreshold * max) / 100)) {
+      if (RtsFlags.GcFlags.generations > 1 &&
+         (RtsFlags.GcFlags.compact ||
+          (max > 0 &&
+           oldest_gen->steps[0].n_blocks > 
+           (RtsFlags.GcFlags.compactThreshold * max) / 100))) {
          oldest_gen->steps[0].is_compacted = 1;
 //       fprintf(stderr,"compaction: on\n", live);
       } else {
@@ -757,6 +758,14 @@ GarbageCollect ( void (*get_roots)(evac_fn), rtsBool force_major_gc )
       // different if compaction is turned on, because we don't need
       // to double the space required to collect the old generation.
       if (max != 0) {
+
+         // this test is necessary to ensure that the calculations
+         // below don't have any negative results - we're working
+         // with unsigned values here.
+         if (max < min_alloc) {
+             heapOverflow();
+         }
+
          if (oldest_gen->steps[0].is_compacted) {
              if ( (size + (size - 1) * (gens - 2) * 2) + min_alloc > max ) {
                  size = (max - min_alloc) / ((gens - 1) * 2 - 1);