/* Allocate more memory from malloc for the heap.
Return a blue block of at least the requested size.
The blue block is chained to a sequence of blue blocks (through their
field 0); the last block of the chain is pointed by field 1 of the
first. There may be a fragment after the last block.
The caller must insert the blocks into the free list.
[request] is a number of words and must be less than or equal
to [Max_wosize].
Return NULL when out of memory.
*/
static value *expand_heap (mlsize_t request)
{
/* these point to headers, but we do arithmetic on them, hence [value *]. */
value *mem, *hp, *prev;
asize_t over_request, malloc_request, remain;
Assert (request <= Max_wosize);
over_request = Whsize_wosize (request + request / 100 * caml_percent_free);
malloc_request = caml_round_heap_chunk_wsz (over_request);
mem = (value *) caml_alloc_for_heap (Bsize_wsize (malloc_request));
if (mem == NULL){
caml_gc_message (0x04, "No room for growing heap\n", 0);
return NULL;
}
remain = malloc_request;
prev = hp = mem;
/* FIXME find a way to do this with a call to caml_make_free_blocks */
while (Wosize_whsize (remain) > Max_wosize){
Hd_hp (hp) = Make_header (Max_wosize, 0, Caml_blue);
#ifdef DEBUG
caml_set_fields (Val_hp (hp), 0, Debug_free_major);
#endif
hp += Whsize_wosize (Max_wosize);
remain -= Whsize_wosize (Max_wosize);
Field (Val_hp (mem), 1) = Field (Val_hp (prev), 0) = Val_hp (hp);
prev = hp;
}
if (remain > 1){
Hd_hp (hp) = Make_header (Wosize_whsize (remain), 0, Caml_blue);
#ifdef DEBUG
caml_set_fields (Val_hp (hp), 0, Debug_free_major);
#endif
Field (Val_hp (mem), 1) = Field (Val_hp (prev), 0) = Val_hp (hp);
Field (Val_hp (hp), 0) = (value) NULL;
}else{
Field (Val_hp (prev), 0) = (value) NULL;
if (remain == 1) Hd_hp (hp) = Make_header (0, 0, Caml_white);
}
Assert (Wosize_hp (mem) >= request);
if (caml_add_to_heap ((char *) mem) != 0){
caml_free_for_heap ((char *) mem);
return NULL;
}
return Op_hp (mem);
}
/* Cut a block of memory into Max_wosize pieces, give them headers,
and optionally merge them into the free list.
arguments:
p: pointer to the first word of the block
size: size of the block (in words)
do_merge: 1 -> do merge; 0 -> do not merge
color: which color to give to the pieces; if [do_merge] is 1, this
is overridden by the merge code, but we have historically used
[Caml_white].
*/
void caml_make_free_blocks (value *p, mlsize_t size, int do_merge, int color)
{
mlsize_t sz;
while (size > 0){
if (size > Whsize_wosize (Max_wosize)){
sz = Whsize_wosize (Max_wosize);
}else{
sz = size;
}
*(header_t *)p = Make_header (Wosize_whsize (sz), 0, color);
if (do_merge) caml_fl_merge_block (Bp_hp (p));
size -= sz;
p += sz;
}
}
value res;
mlsize_t whsize, wosize;
unsigned long bhsize;
color_t color;
header_t hd;
whsize = getword(chan);
if (whsize == 0) {
res = (value) getword(chan);
if (IS_LONG(res))
return res;
else
return Atom(res >> 2);
}
bhsize = Bsize_wsize (whsize);
wosize = Wosize_whsize (whsize);
#if (SIZEOF_LONG_P == 8)
if (magic == Little_endian_32_magic_number ||
magic == Big_endian_32_magic_number) {
/* Expansion 32 -> 64 required */
mlsize_t whsize32;
value32 * block;
whsize32 = whsize;
block = (value32 *) stat_alloc(whsize32 * sizeof(value32));
if (really_getblock(chan, (char *) block,
whsize32 * sizeof(value32)) == 0) {
stat_free((char *) block);
failwith ("intern : truncated object");
}
if (magic == Wrong_endian_32_magic_number)
rev_pointers_32(block, whsize32);
static void do_compaction_r (CAML_R)
{
char *ch, *chend;
Assert (caml_gc_phase == Phase_idle);
caml_gc_message (0x10, "Compacting heap...\n", 0);
#ifdef DEBUG
caml_heap_check_r (ctx);
#endif
/* First pass: encode all noninfix headers. */
{
ch = caml_heap_start;
while (ch != NULL){
header_t *p = (header_t *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
header_t hd = Hd_hp (p);
mlsize_t sz = Wosize_hd (hd);
if (Is_blue_hd (hd)){
/* Free object. Give it a string tag. */
Hd_hp (p) = Make_ehd (sz, String_tag, 3);
}else{ Assert (Is_white_hd (hd));
/* Live object. Keep its tag. */
Hd_hp (p) = Make_ehd (sz, Tag_hd (hd), 3);
}
p += Whsize_wosize (sz);
}
ch = Chunk_next (ch);
}
}
/* Second pass: invert pointers.
Link infix headers in each block in an inverted list of inverted lists.
Don't forget roots and weak pointers. */
{
/* Invert roots first because the threads library needs some heap
data structures to find its roots. Fortunately, it doesn't need
the headers (see above). */
caml_do_roots_r (ctx, invert_root_r);
caml_final_do_weak_roots_r (ctx, invert_root_r);
ch = caml_heap_start;
while (ch != NULL){
word *p = (word *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
word q = *p;
size_t sz, i;
tag_t t;
word *infixes;
while (Ecolor (q) == 0) q = * (word *) q;
sz = Whsize_ehd (q);
t = Tag_ehd (q);
if (t == Infix_tag){
/* Get the original header of this block. */
infixes = p + sz;
q = *infixes;
while (Ecolor (q) != 3) q = * (word *) (q & ~(uintnat)3);
sz = Whsize_ehd (q);
t = Tag_ehd (q);
}
if (t < No_scan_tag){
for (i = 1; i < sz; i++) invert_pointer_at_r (ctx, &(p[i]));
}
p += sz;
}
ch = Chunk_next (ch);
}
/* Invert weak pointers. */
{
value *pp = &caml_weak_list_head;
value p;
word q;
size_t sz, i;
while (1){
p = *pp;
if (p == (value) NULL) break;
q = Hd_val (p);
while (Ecolor (q) == 0) q = * (word *) q;
sz = Wosize_ehd (q);
for (i = 1; i < sz; i++){
if (Field (p,i) != caml_weak_none){
invert_pointer_at_r (ctx, (word *) &(Field (p,i)));
}
}
invert_pointer_at_r (ctx, (word *) pp);
pp = &Field (p, 0);
}
}
}
/* Third pass: reallocate virtually; revert pointers; decode headers.
Rebuild infix headers. */
{
init_compact_allocate_r (ctx);
ch = caml_heap_start;
while (ch != NULL){
word *p = (word *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
word q = *p;
if (Ecolor (q) == 0 || Tag_ehd (q) == Infix_tag){
/* There were (normal or infix) pointers to this block. */
size_t sz;
tag_t t;
char *newadr;
word *infixes = NULL;
while (Ecolor (q) == 0) q = * (word *) q;
sz = Whsize_ehd (q);
t = Tag_ehd (q);
if (t == Infix_tag){
/* Get the original header of this block. */
infixes = p + sz;
q = *infixes; Assert (Ecolor (q) == 2);
while (Ecolor (q) != 3) q = * (word *) (q & ~(uintnat)3);
sz = Whsize_ehd (q);
t = Tag_ehd (q);
}
newadr = compact_allocate_r (ctx, Bsize_wsize (sz));
q = *p;
while (Ecolor (q) == 0){
word next = * (word *) q;
* (word *) q = (word) Val_hp (newadr);
q = next;
}
*p = Make_header (Wosize_whsize (sz), t, Caml_white);
if (infixes != NULL){
/* Rebuild the infix headers and revert the infix pointers. */
while (Ecolor ((word) infixes) != 3){
infixes = (word *) ((word) infixes & ~(uintnat) 3);
q = *infixes;
while (Ecolor (q) == 2){
word next;
q = (word) q & ~(uintnat) 3;
next = * (word *) q;
* (word *) q = (word) Val_hp ((word *) newadr + (infixes - p));
q = next;
} Assert (Ecolor (q) == 1 || Ecolor (q) == 3);
*infixes = Make_header (infixes - p, Infix_tag, Caml_white);
infixes = (word *) q;
}
}
p += sz;
}else{ Assert (Ecolor (q) == 3);
/* This is guaranteed only if caml_compact_heap was called after a
nonincremental major GC: Assert (Tag_ehd (q) == String_tag);
*/
/* No pointers to the header and no infix header:
the object was free. */
*p = Make_header (Wosize_ehd (q), Tag_ehd (q), Caml_blue);
p += Whsize_ehd (q);
}
}
ch = Chunk_next (ch);
}
}
/* Fourth pass: reallocate and move objects.
Use the exact same allocation algorithm as pass 3. */
{
init_compact_allocate_r (ctx);
ch = caml_heap_start;
while (ch != NULL){
word *p = (word *) ch;
chend = ch + Chunk_size (ch);
while ((char *) p < chend){
word q = *p;
if (Color_hd (q) == Caml_white){
size_t sz = Bhsize_hd (q);
char *newadr = compact_allocate_r (ctx, sz);
memmove (newadr, p, sz);
p += Wsize_bsize (sz);
}else{
Assert (Color_hd (q) == Caml_blue);
p += Whsize_hd (q);
}
}
ch = Chunk_next (ch);
}
}
/* Shrink the heap if needed. */
{
/* Find the amount of live data and the unshrinkable free space. */
asize_t live = 0;
asize_t free = 0;
asize_t wanted;
ch = caml_heap_start;
while (ch != NULL){
if (Chunk_alloc (ch) != 0){
live += Wsize_bsize (Chunk_alloc (ch));
free += Wsize_bsize (Chunk_size (ch) - Chunk_alloc (ch));
}
ch = Chunk_next (ch);
}
/* Add up the empty chunks until there are enough, then remove the
other empty chunks. */
wanted = caml_percent_free * (live / 100 + 1);
ch = caml_heap_start;
while (ch != NULL){
char *next_chunk = Chunk_next (ch); /* Chunk_next (ch) will be erased */
if (Chunk_alloc (ch) == 0){
if (free < wanted){
free += Wsize_bsize (Chunk_size (ch));
}else{
caml_shrink_heap_r (ctx, ch);
}
}
ch = next_chunk;
}
}
/* Rebuild the free list. */
{
ch = caml_heap_start;
caml_fl_reset_r (ctx);
while (ch != NULL){
if (Chunk_size (ch) > Chunk_alloc (ch)){
caml_make_free_blocks_r (ctx, (value *) (ch + Chunk_alloc (ch)),
Wsize_bsize (Chunk_size(ch)-Chunk_alloc(ch)), 1,
Caml_white);
}
ch = Chunk_next (ch);
}
}
++ caml_stat_compactions;
caml_gc_message (0x10, "done.\n", 0);
}