[project @ 2003-07-30 10:38:42 by simonmar]

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

diff --git a/ghc/rts/BlockAlloc.c b/ghc/rts/BlockAlloc.c
index 7c7dcae..8e09d0c 100644 (file)
--- a/ghc/rts/BlockAlloc.c
+++ b/ghc/rts/BlockAlloc.c
@@ -1,7 +1,7 @@
 /* -----------------------------------------------------------------------------
- * $Id: BlockAlloc.c,v 1.4 1999/02/05 16:02:35 simonm Exp $
+ * $Id: BlockAlloc.c,v 1.16 2003/02/18 05:47:53 sof Exp $
  *
- * (c) The GHC Team 1998-1999
+ * (c) The GHC Team 1998-2000
  * 
  * The block allocator and free list manager.
  *
@@ -16,17 +16,20 @@
  *
  * ---------------------------------------------------------------------------*/
 
+#include "PosixSource.h"
 #include "Rts.h"
 #include "RtsFlags.h"
 #include "RtsUtils.h"
 #include "BlockAlloc.h"
 #include "MBlock.h"
 
+#include <string.h>
+
 static void    initMBlock(void *mblock);
 static bdescr *allocMegaGroup(nat mblocks);
 static void    freeMegaGroup(bdescr *bd);
 
-static bdescr *free_list;
+static bdescr *free_list = NULL;
 
 /* -----------------------------------------------------------------------------
    Initialisation
@@ -34,7 +37,7 @@ static bdescr *free_list;
 
 void initBlockAllocator(void)
 {
-  free_list = NULL;
+    // The free list starts off NULL
 }
 
 /* -----------------------------------------------------------------------------
@@ -52,6 +55,7 @@ initGroup(nat n, bdescr *head)
     head->free = head->start;
     for (i=1, bd = head+1; i < n; i++, bd++) {
       bd->free = 0;
+      bd->blocks = 0;
       bd->link = head;
     }
   }
@@ -63,6 +67,8 @@ allocGroup(nat n)
   void *mblock;
   bdescr *bd, **last;
 
+  ASSERT(n != 0);
+
   if (n > BLOCKS_PER_MBLOCK) {
     return allocMegaGroup(BLOCKS_TO_MBLOCKS(n));
   }
@@ -73,6 +79,9 @@ allocGroup(nat n)
       *last = bd->link;
       /* no initialisation necessary - this is already a
        * self-contained block group. */
+#ifdef DEBUG
+      bd->free = bd->start;    /* block isn't free now */
+#endif
       return bd;
     }
     if (bd->blocks >  n) {     /* block too big... */
@@ -88,8 +97,10 @@ allocGroup(nat n)
   initMBlock(mblock);          /* initialise the start fields */
   bd = FIRST_BDESCR(mblock);
   initGroup(n,bd);             /* we know the group will fit */
-  initGroup(BLOCKS_PER_MBLOCK-n, bd+n);
-  freeGroup(bd+n);             /* add the rest on to the free list */
+  if (n < BLOCKS_PER_MBLOCK) {
+    initGroup(BLOCKS_PER_MBLOCK-n, bd+n);
+    freeGroup(bd+n);           /* add the rest on to the free list */
+  }
   return bd;
 }
 
@@ -126,7 +137,9 @@ allocMegaGroup(nat n)
 
     if (bd->blocks == BLOCKS_PER_MBLOCK) {     /* whole megablock found */
 
-      if (grp_start == NULL) { /* is it the first one we've found? */
+      /* is it the first one we've found or a non-contiguous megablock? */
+      if (grp_start == NULL ||
+          bd->start != last->start + MBLOCK_SIZE/sizeof(W_)) {
        grp_start = bd;
        grp_prev  = last;
        mbs_found = 1;
@@ -185,15 +198,17 @@ static inline bdescr *
 coalesce(bdescr *p)
 {
   bdescr *bd, *q;
-  nat i;
+  nat i, blocks;
 
   q = p->link;
   if (q != NULL && p->start + p->blocks * BLOCK_SIZE_W == q->start) {
     /* can coalesce */
     p->blocks += q->blocks;
     p->link    = q->link;
-    for (i = 0, bd = q; i < q->blocks; bd++, i++) {
+    blocks = q->blocks;
+    for (i = 0, bd = q; i < blocks; bd++, i++) {
        bd->free = 0;
+       bd->blocks = 0;
        bd->link = p;
     }
     return p;
@@ -215,7 +230,7 @@ freeGroup(bdescr *p)
 #ifdef DEBUG
   p->free = (void *)-1;  /* indicates that this block is free */
   p->step = NULL;
-  p->gen  = NULL;
+  p->gen_no = 0;
   /* fill the block group with garbage if sanity checking is on */
   IF_DEBUG(sanity,memset(p->start, 0xaa, p->blocks * BLOCK_SIZE));
 #endif
@@ -250,7 +265,7 @@ freeMegaGroup(bdescr *p)
 
   n = p->blocks * BLOCK_SIZE / MBLOCK_SIZE + 1;
   for (; n > 0; (W_)p += MBLOCK_SIZE, n--) {
-    initMBlock((void *)((W_)p & ~MBLOCK_MASK));
+    initMBlock(MBLOCK_ROUND_DOWN(p));
     initGroup(BLOCKS_PER_MBLOCK, p);
     freeGroup(p);
   }
@@ -291,6 +306,18 @@ initMBlock(void *mblock)
    -------------------------------------------------------------------------- */
 
 #ifdef DEBUG
+static void
+checkWellFormedGroup( bdescr *bd )
+{
+    nat i;
+
+    for (i = 1; i < bd->blocks; i++) {
+       ASSERT(bd[i].blocks == 0);
+       ASSERT(bd[i].free   == 0);
+       ASSERT(bd[i].link   == bd);
+    }
+}
+
 void
 checkFreeListSanity(void)
 {
@@ -301,6 +328,7 @@ checkFreeListSanity(void)
             fprintf(stderr,"group at 0x%x, length %d blocks\n", 
                     (nat)bd->start, bd->blocks));
     ASSERT(bd->blocks > 0);
+    checkWellFormedGroup(bd);
     if (bd->link != NULL) {
       /* make sure we're fully coalesced */
       ASSERT(bd->start + bd->blocks * BLOCK_SIZE_W != bd->link->start);