Keep track of an accurate count of live words in each step

[ghc-hetmet.git] / includes / Block.h

diff --git a/includes/Block.h b/includes/Block.h
index dd3e201..e2e691a 100644 (file)
--- a/includes/Block.h
+++ b/includes/Block.h
@@ -54,6 +54,7 @@ typedef struct bdescr_ {
   union { 
       struct bdescr_ *back;    /* used (occasionally) for doubly-linked lists*/
       StgWord *bitmap;
+      StgPtr  scan;             /* scan pointer for copying GC */
   } u;
   unsigned int gen_no;         /* generation */
   struct step_ *step;          /* step */
@@ -227,21 +228,30 @@ void freeChain(bdescr *p);
 void freeGroup_lock(bdescr *p);
 void freeChain_lock(bdescr *p);
 
-/* Round a value to megablocks --------------------------------------------- */
+bdescr * splitBlockGroup (bdescr *bd, nat blocks);
 
-#define WORDS_PER_MBLOCK  (BLOCKS_PER_MBLOCK * BLOCK_SIZE_W)
+/* Round a value to megablocks --------------------------------------------- */
 
-INLINE_HEADER nat
-round_to_mblocks(nat words)
+// We want to allocate an object around a given size, round it up or
+// down to the nearest size that will fit in an mblock group.
+INLINE_HEADER StgWord
+round_to_mblocks(StgWord words)
 {
-  if (words > WORDS_PER_MBLOCK) {
-    if ((words % WORDS_PER_MBLOCK) < (WORDS_PER_MBLOCK / 2)) {
-      words = (words / WORDS_PER_MBLOCK) * WORDS_PER_MBLOCK;
-    } else {
-      words = ((words / WORDS_PER_MBLOCK) + 1) * WORDS_PER_MBLOCK;
+    if (words > BLOCKS_PER_MBLOCK * BLOCK_SIZE_W) {
+        // first, ignore the gap at the beginning of the first mblock by
+        // adding it to the total words.  Then we can pretend we're
+        // dealing in a uniform unit of megablocks.
+        words += FIRST_BLOCK_OFF/sizeof(W_);
+
+        if ((words % MBLOCK_SIZE_W) < (MBLOCK_SIZE_W / 2)) {
+            words = (words / MBLOCK_SIZE_W) * MBLOCK_SIZE_W;
+        } else {
+            words = ((words / MBLOCK_SIZE_W) + 1) * MBLOCK_SIZE_W;
+        }
+
+        words -= FIRST_BLOCK_OFF/sizeof(W_);
     }
-  }
-  return words;
+    return words;
 }
 
 #endif /* !CMINUSMINUS */