/* 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);
}
/* 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.
The request must be less than or equal to Max_wosize.
Return NULL when out of memory.
*/
static char *expand_heap (mlsize_t request)
{
char *mem, *hp, *prev;
asize_t over_request, malloc_request, remain;
Assert (request <= Max_wosize);
over_request = request + request / 100 * caml_percent_free;
malloc_request = caml_round_heap_chunk_size (Bhsize_wosize (over_request));
mem = caml_alloc_for_heap (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_bhsize (remain) > Max_wosize){
Hd_hp (hp) = Make_header (Max_wosize, 0, Caml_blue);
#ifdef DEBUG
caml_set_fields (Bp_hp (hp), 0, Debug_free_major);
#endif
hp += Bhsize_wosize (Max_wosize);
remain -= Bhsize_wosize (Max_wosize);
Field (Op_hp (mem), 1) = Field (Op_hp (prev), 0) = (value) Op_hp (hp);
prev = hp;
}
if (remain > 1){
Hd_hp (hp) = Make_header (Wosize_bhsize (remain), 0, Caml_blue);
#ifdef DEBUG
caml_set_fields (Bp_hp (hp), 0, Debug_free_major);
#endif
Field (Op_hp (mem), 1) = Field (Op_hp (prev), 0) = (value) Op_hp (hp);
Field (Op_hp (hp), 0) = (value) NULL;
}else{
Field (Op_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 (mem) != 0){
caml_free_for_heap (mem);
return NULL;
}
return Bp_hp (mem);
}
/* [caml_fl_merge_block] returns the head pointer of the next block after [bp],
because merging blocks may change the size of [bp]. */
char *caml_fl_merge_block (char *bp)
{
char *prev, *cur, *adj;
header_t hd = Hd_bp (bp);
mlsize_t prev_wosz;
caml_fl_cur_size += Whsize_hd (hd);
#ifdef DEBUG
caml_set_fields (bp, 0, Debug_free_major);
#endif
prev = caml_fl_merge;
cur = Next (prev);
/* The sweep code makes sure that this is the right place to insert
this block: */
Assert (prev < bp || prev == Fl_head);
Assert (cur > bp || cur == NULL);
if (policy == Policy_first_fit) truncate_flp (prev);
/* If [last_fragment] and [bp] are adjacent, merge them. */
if (last_fragment == Hp_bp (bp)){
mlsize_t bp_whsz = Whsize_bp (bp);
if (bp_whsz <= Max_wosize){
hd = Make_header (bp_whsz, 0, Caml_white);
bp = last_fragment;
Hd_bp (bp) = hd;
caml_fl_cur_size += Whsize_wosize (0);
}
}
/* If [bp] and [cur] are adjacent, remove [cur] from the free-list
and merge them. */
adj = bp + Bosize_hd (hd);
if (adj == Hp_bp (cur)){
char *next_cur = Next (cur);
mlsize_t cur_whsz = Whsize_bp (cur);
if (Wosize_hd (hd) + cur_whsz <= Max_wosize){
Next (prev) = next_cur;
if (policy == Policy_next_fit && fl_prev == cur) fl_prev = prev;
hd = Make_header (Wosize_hd (hd) + cur_whsz, 0, Caml_blue);
Hd_bp (bp) = hd;
adj = bp + Bosize_hd (hd);
#ifdef DEBUG
fl_last = NULL;
Next (cur) = (char *) Debug_free_major;
Hd_bp (cur) = Debug_free_major;
#endif
cur = next_cur;
}
}
/* If [prev] and [bp] are adjacent merge them, else insert [bp] into
the free-list if it is big enough. */
prev_wosz = Wosize_bp (prev);
if (prev + Bsize_wsize (prev_wosz) == Hp_bp (bp)
&& prev_wosz + Whsize_hd (hd) < Max_wosize){
Hd_bp (prev) = Make_header (prev_wosz + Whsize_hd (hd), 0,Caml_blue);
#ifdef DEBUG
Hd_bp (bp) = Debug_free_major;
#endif
Assert (caml_fl_merge == prev);
}else if (Wosize_hd (hd) != 0){
Hd_bp (bp) = Bluehd_hd (hd);
Next (bp) = cur;
Next (prev) = bp;
caml_fl_merge = bp;
}else{
/* This is a fragment. Leave it in white but remember it for eventual
merging with the next block. */
last_fragment = bp;
caml_fl_cur_size -= Whsize_wosize (0);
}
return adj;
}
