/* -----------------------------------------------------------------------------
*
- * (c) The GHC Team 1998-2005
+ * (c) The GHC Team 1998-2000
*
* The block allocator and free list manager.
*
-------------------------------------------------------------------------- */
STATIC_INLINE void
-initGroupTail(nat n, bdescr *head, bdescr *tail)
-{
- bdescr *bd;
- nat i;
-
- for (i=0, bd = tail; i < n; i++, bd++) {
- bd->flags = 0;
- bd->free = 0;
- bd->blocks = 0;
- bd->link = head;
- }
-}
-
-STATIC_INLINE void
initGroup(nat n, bdescr *head)
{
+ bdescr *bd;
+ nat i;
+
if (n != 0) {
head->blocks = n;
head->free = head->start;
head->link = NULL;
- head->flags = 0;
- initGroupTail( n-1, head, head+1 );
+ for (i=1, bd = head+1; i < n; i++, bd++) {
+ bd->free = 0;
+ bd->blocks = 0;
+ bd->link = head;
+ }
}
}
last = &free_list;
for (bd = free_list; bd != NULL; bd = bd->link) {
if (bd->blocks == n) { /* exactly the right size! */
- if (bd->link) {
- bd->link->u.back = bd->u.back;
- }
*last = bd->link;
/* no initialisation necessary - this is already a
* self-contained block group. */
- bd->flags = 0;
- bd->free = bd->start;
- bd->link = NULL;
+ bd->free = bd->start; /* block isn't free now */
+ bd->link = NULL;
return bd;
}
if (bd->blocks > n) { /* block too big... */
last = bd;
}
- /* found all the megablocks we need on the free list */
+ /* found all the megablocks we need on the free list
+ */
if (mbs_found == n) {
/* remove the megablocks from the free list */
if (grp_prev == NULL) { /* bd now points to the last mblock */
free_list = bd->link;
- if (free_list) {
- free_list->u.back = NULL;
- }
} else {
grp_prev->link = bd->link;
- if (bd->link) {
- bd->link->u.back = grp_prev;
- }
}
}
- /* the free list wasn't sufficient, allocate all new mblocks. */
+ /* the free list wasn't sufficient, allocate all new mblocks.
+ */
else {
void *mblock = getMBlocks(n);
initMBlock(mblock); /* only need to init the 1st one */
De-Allocation
-------------------------------------------------------------------------- */
-/* coalesce the group p with its predecessor and successor groups, if possible
+/* coalesce the group p with p->link if possible.
*
- * Returns NULL if no coalescing was done, otherwise returns a
+ * Returns p->link if no coalescing was done, otherwise returns a
* pointer to the newly enlarged group p.
*/
STATIC_INLINE bdescr *
coalesce(bdescr *p)
{
- bdescr *first, *q, *result = NULL;
-
- /* Get first megablock descriptor */
- first = FIRST_BDESCR(MBLOCK_ROUND_DOWN(p->start));
-
- /* Attempt to coalesce with predecessor if not the first block */
- if (p != first) {
- q = p - 1;
- if (!q->blocks) { // not a block head?
- q = q->link; // find the head.
- }
- /* Predecessor is free? */
- if (q->flags & BF_FREE) {
- q->blocks += p->blocks;
- initGroupTail( p->blocks, q, p );
- p = result = q;
- }
- }
-
- /* Attempt to coalesce with successor if not the last block */
- q = p + p->blocks;
- if (q != first + BLOCKS_PER_MBLOCK) {
- /* Successor is free */
- if (q->flags & BF_FREE) {
- if (result) {
- /* p is on free_list, q is on free_list, unlink
- * q completely and patch up list
- */
- if (q->u.back) {
- q->u.back->link = q->link;
- }
- if (q->link) {
- q->link->u.back = q->u.back;
- }
- if (free_list == q) {
- free_list = q->link;
- }
- } else {
- /* p is not on free_list just assume q's links */
- p->u.back = q->u.back;
- if (p->u.back) {
- p->u.back->link = p;
- }
- p->link = q->link;
- if (p->link) {
- p->link->u.back = p;
- }
- if (q == free_list) {
- free_list = p;
- free_list->u.back = NULL;
- }
- }
-
- p->blocks += q->blocks;
- initGroupTail( q->blocks, p, q );
- result = p;
- }
+ bdescr *bd, *q;
+ 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;
+ blocks = q->blocks;
+ for (i = 0, bd = q; i < blocks; bd++, i++) {
+ bd->free = 0;
+ bd->blocks = 0;
+ bd->link = p;
}
-
- return result;
+ return p;
+ }
+ return q;
}
void
freeGroup(bdescr *p)
{
+ bdescr *bd, *last;
+
/* are we dealing with a megablock group? */
if (p->blocks > BLOCKS_PER_MBLOCK) {
freeMegaGroup(p);
return;
}
- p->flags = BF_FREE;
- p->u.back = NULL;
- p->link = NULL;
+
+ p->free = (void *)-1; /* indicates that this block is free */
p->step = 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));
- if (!coalesce(p)) {
- dbl_link_onto(p, &free_list);
+ /* find correct place in free list to place new group */
+ last = NULL;
+ for (bd = free_list; bd != NULL && bd->start < p->start;
+ bd = bd->link) {
+ last = bd;
+ }
+
+ /* now, last = previous group (or NULL) */
+ if (last == NULL) {
+ p->link = free_list;
+ free_list = p;
+ } else {
+ /* coalesce with previous group if possible */
+ p->link = last->link;
+ last->link = p;
+ p = coalesce(last);
}
+ /* coalesce with next group if possible */
+ coalesce(p);
IF_DEBUG(sanity, checkFreeListSanity());
}
#ifdef DEBUG
static void
-checkWellFormedGroup(bdescr *bd)
+checkWellFormedGroup( bdescr *bd )
{
nat i;
debugBelch("group at 0x%x, length %d blocks\n",
(nat)bd->start, bd->blocks));
ASSERT(bd->blocks > 0);
- ASSERT(bd->link ? bd->link->u.back == bd : 1);
- ASSERT(bd->u.back ? bd->u.back->link == bd : 1);
checkWellFormedGroup(bd);
if (bd->link != NULL) {
/* make sure we're fully coalesced */
ASSERT(bd->start + bd->blocks * BLOCK_SIZE_W != bd->link->start);
+ ASSERT(bd->start < bd->link->start);
}
}
}
projects / ghc-hetmet.git / commitdiff