403 lines
12 KiB
C
403 lines
12 KiB
C
/***********************************************************************/
|
|
/* */
|
|
/* Objective Caml */
|
|
/* */
|
|
/* Damien Doligez, projet Para, INRIA Rocquencourt */
|
|
/* */
|
|
/* Copyright 1996 Institut National de Recherche en Informatique et */
|
|
/* en Automatique. All rights reserved. This file is distributed */
|
|
/* under the terms of the GNU Library General Public License. */
|
|
/* */
|
|
/***********************************************************************/
|
|
|
|
/* $Id$ */
|
|
|
|
#include <limits.h>
|
|
|
|
#include "compact.h"
|
|
#include "custom.h"
|
|
#include "config.h"
|
|
#include "fail.h"
|
|
#include "finalise.h"
|
|
#include "freelist.h"
|
|
#include "gc.h"
|
|
#include "gc_ctrl.h"
|
|
#include "major_gc.h"
|
|
#include "misc.h"
|
|
#include "mlvalues.h"
|
|
#include "roots.h"
|
|
#include "weak.h"
|
|
|
|
unsigned long percent_free;
|
|
long major_heap_increment;
|
|
char *heap_start, *heap_end;
|
|
page_table_entry *page_table;
|
|
asize_t page_low, page_high;
|
|
char *gc_sweep_hp;
|
|
int gc_phase;
|
|
static value *gray_vals;
|
|
value *gray_vals_cur, *gray_vals_end;
|
|
static asize_t gray_vals_size;
|
|
static int heap_is_pure; /* The heap is pure if the only gray objects
|
|
below [markhp] are also in [gray_vals]. */
|
|
unsigned long allocated_words;
|
|
double extra_heap_memory;
|
|
extern char *fl_merge; /* Defined in freelist.c. */
|
|
|
|
static char *markhp, *chunk, *limit;
|
|
|
|
static void update_weak_pointers (void);
|
|
|
|
static void realloc_gray_vals (void)
|
|
{
|
|
value *new;
|
|
|
|
Assert (gray_vals_cur == gray_vals_end);
|
|
if (gray_vals_size < stat_heap_size / 128){
|
|
gc_message (0x08, "Growing gray_vals to %luk bytes\n",
|
|
(long) gray_vals_size * sizeof (value) / 512);
|
|
new = (value *) realloc ((char *) gray_vals,
|
|
2 * gray_vals_size * sizeof (value));
|
|
if (new == NULL){
|
|
gc_message (0x08, "No room for growing gray_vals\n", 0);
|
|
gray_vals_cur = gray_vals;
|
|
heap_is_pure = 0;
|
|
}else{
|
|
gray_vals = new;
|
|
gray_vals_cur = gray_vals + gray_vals_size;
|
|
gray_vals_size *= 2;
|
|
gray_vals_end = gray_vals + gray_vals_size;
|
|
}
|
|
}else{
|
|
gray_vals_cur = gray_vals + gray_vals_size / 2;
|
|
heap_is_pure = 0;
|
|
}
|
|
}
|
|
|
|
void darken (value v, value *p /* not used */)
|
|
{
|
|
if (Is_block (v) && Is_in_heap (v)) {
|
|
if (Tag_val(v) == Infix_tag) v -= Infix_offset_val(v);
|
|
if (Is_white_val (v)){
|
|
Hd_val (v) = Grayhd_hd (Hd_val (v));
|
|
*gray_vals_cur++ = v;
|
|
if (gray_vals_cur >= gray_vals_end) realloc_gray_vals ();
|
|
}
|
|
}
|
|
}
|
|
|
|
static void start_cycle (void)
|
|
{
|
|
Assert (gc_phase == Phase_idle);
|
|
Assert (gray_vals_cur == gray_vals);
|
|
gc_message (0x01, "Starting new major GC cycle\n", 0);
|
|
darken_all_roots();
|
|
gc_phase = Phase_mark;
|
|
markhp = NULL;
|
|
#ifdef DEBUG
|
|
heap_check ();
|
|
#endif
|
|
}
|
|
|
|
static void mark_slice (long work)
|
|
{
|
|
value *gray_vals_ptr; /* Local copy of gray_vals_cur */
|
|
value v, child;
|
|
header_t hd;
|
|
mlsize_t size, i;
|
|
|
|
gc_message (0x40, "Marking %lu words\n", work);
|
|
gray_vals_ptr = gray_vals_cur;
|
|
while (work > 0){
|
|
if (gray_vals_ptr > gray_vals){
|
|
v = *--gray_vals_ptr;
|
|
hd = Hd_val(v);
|
|
Assert (Is_gray_hd (hd));
|
|
Hd_val (v) = Blackhd_hd (hd);
|
|
size = Wosize_hd(hd);
|
|
if (Tag_hd (hd) < No_scan_tag){
|
|
for (i = 0; i < size; i++){
|
|
child = Field (v, i);
|
|
if (Is_block (child) && Is_in_heap (child)) {
|
|
hd = Hd_val(child);
|
|
if (Tag_hd(hd) == Infix_tag) {
|
|
child -= Infix_offset_val(child);
|
|
hd = Hd_val(child);
|
|
}
|
|
if (Is_white_hd (hd)){
|
|
Hd_val (child) = Grayhd_hd (hd);
|
|
*gray_vals_ptr++ = child;
|
|
if (gray_vals_ptr >= gray_vals_end) {
|
|
gray_vals_cur = gray_vals_ptr;
|
|
realloc_gray_vals ();
|
|
gray_vals_ptr = gray_vals_cur;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
work -= Whsize_wosize(size);
|
|
}else if (markhp != NULL){
|
|
if (markhp == limit){
|
|
chunk = Chunk_next (chunk);
|
|
if (chunk == NULL){
|
|
markhp = NULL;
|
|
}else{
|
|
markhp = chunk;
|
|
limit = chunk + Chunk_size (chunk);
|
|
}
|
|
}else{
|
|
if (Is_gray_val (Val_hp (markhp))){
|
|
Assert (gray_vals_ptr == gray_vals);
|
|
*gray_vals_ptr++ = Val_hp (markhp);
|
|
}
|
|
markhp += Bhsize_hp (markhp);
|
|
}
|
|
}else if (!heap_is_pure){
|
|
heap_is_pure = 1;
|
|
chunk = heap_start;
|
|
markhp = chunk;
|
|
limit = chunk + Chunk_size (chunk);
|
|
}else if (gc_phase == Phase_mark){
|
|
/* The main marking phase is over. Handle finalised values. */
|
|
gray_vals_cur = gray_vals_ptr;
|
|
final_update ();
|
|
gray_vals_ptr = gray_vals_cur;
|
|
gc_phase = Phase_mark_final;
|
|
}else{
|
|
/* Marking is done. */
|
|
|
|
update_weak_pointers ();
|
|
|
|
/* Initialise the sweep phase. */
|
|
gray_vals_cur = gray_vals_ptr;
|
|
gc_sweep_hp = heap_start;
|
|
fl_init_merge ();
|
|
gc_phase = Phase_sweep;
|
|
chunk = heap_start;
|
|
gc_sweep_hp = chunk;
|
|
limit = chunk + Chunk_size (chunk);
|
|
work = 0;
|
|
}
|
|
}
|
|
gray_vals_cur = gray_vals_ptr;
|
|
}
|
|
|
|
/* Walk through the linked list of weak arrays.
|
|
Arrays that are white are removed from this list.
|
|
For the other arrays, pointers to white objects are erased.
|
|
*/
|
|
static void update_weak_pointers (void)
|
|
{
|
|
value *prev = &weak_list_head;
|
|
value *cur = (value *) *prev;
|
|
mlsize_t sz, i;
|
|
|
|
while (cur != NULL){
|
|
if (Color_val (cur) == Caml_white){
|
|
*prev = Field (cur, 0);
|
|
cur = (value *) *prev;
|
|
}else{
|
|
value curfield;
|
|
|
|
sz = Wosize_val (cur);
|
|
for (i = 1; i < sz; i++){
|
|
curfield = Field (cur, i);
|
|
if (curfield != 0 && Is_block (curfield) && Is_white_val (curfield)){
|
|
Field (cur, i) = 0;
|
|
}
|
|
}
|
|
prev = &Field (cur, 0);
|
|
cur = (value *) *prev;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void sweep_slice (long int work)
|
|
{
|
|
char *hp;
|
|
header_t hd;
|
|
|
|
gc_message (0x40, "Sweeping %lu words\n", work);
|
|
while (work > 0){
|
|
if (gc_sweep_hp < limit){
|
|
hp = gc_sweep_hp;
|
|
hd = Hd_hp (hp);
|
|
work -= Whsize_hd (hd);
|
|
gc_sweep_hp += Bhsize_hd (hd);
|
|
switch (Color_hd (hd)){
|
|
case Caml_white:
|
|
if (Tag_hd (hd) == Custom_tag){
|
|
void (*final_fun)(value) = Custom_ops_val(Val_hp(hp))->finalize;
|
|
if (final_fun != NULL) final_fun(Val_hp(hp));
|
|
}
|
|
gc_sweep_hp = fl_merge_block (Bp_hp (hp));
|
|
break;
|
|
case Caml_blue:
|
|
/* Only the blocks of the free-list are blue. See [freelist.c]. */
|
|
fl_merge = Bp_hp (hp);
|
|
break;
|
|
default: /* gray or black */
|
|
Assert (Color_hd (hd) == Caml_black);
|
|
Hd_hp (hp) = Whitehd_hd (hd);
|
|
break;
|
|
}
|
|
Assert (gc_sweep_hp <= limit);
|
|
}else{
|
|
chunk = Chunk_next (chunk);
|
|
if (chunk == NULL){
|
|
/* Sweeping is done. */
|
|
++ stat_major_collections;
|
|
work = 0;
|
|
gc_phase = Phase_idle;
|
|
}else{
|
|
gc_sweep_hp = chunk;
|
|
limit = chunk + Chunk_size (chunk);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* The main entry point for the GC. Called after each minor GC. */
|
|
void major_collection_slice (void)
|
|
{
|
|
double p;
|
|
/*
|
|
Free memory at the start of the GC cycle (garbage + free list) (assumed):
|
|
FM = stat_heap_size * percent_free / (100 + percent_free)
|
|
Garbage at the start of the GC cycle:
|
|
G = FM * 2/3
|
|
Proportion of free memory consumed since the previous slice:
|
|
PH = allocated_words / G
|
|
= 3 * allocated_words * (100 + percent_free)
|
|
/ (2 * stat_heap_size * percent_free)
|
|
Proportion of extra-heap memory consumed since the previous slice:
|
|
PE = extra_heap_memory
|
|
Proportion of total work to do in this slice:
|
|
P = max (PH, PE)
|
|
Amount of marking work for the GC cycle:
|
|
MW = stat_heap_size * 100 / (100 + percent_free)
|
|
Amount of sweeping work for the GC cycle:
|
|
SW = stat_heap_size
|
|
Amount of marking work for this slice:
|
|
MS = P * MW
|
|
MS = P * stat_heap_size * 100 / (100 + percent_free)
|
|
Amount of sweeping work for this slice:
|
|
SS = P * SW
|
|
SS = P * stat_heap_size
|
|
This slice will either mark 2*MS words or sweep 2*SS words.
|
|
*/
|
|
|
|
#define Margin 100 /* Make it a little faster to be on the safe side. */
|
|
|
|
if (gc_phase == Phase_idle) start_cycle ();
|
|
|
|
p = 1.5 * allocated_words * (100 + percent_free)
|
|
/ stat_heap_size / percent_free;
|
|
if (p < extra_heap_memory) p = extra_heap_memory;
|
|
|
|
gc_message (0x40, "allocated_words = %lu\n", allocated_words);
|
|
gc_message (0x40, "extra_heap_memory = %luu\n",
|
|
(unsigned long) (extra_heap_memory * 1000000));
|
|
gc_message (0x40, "amount of work to do = %luu\n",
|
|
(unsigned long) (p * 1000000));
|
|
|
|
if (gc_phase == Phase_mark || gc_phase == Phase_mark_final){
|
|
long work = (long) (p * stat_heap_size * 100 / (100+percent_free)) + Margin;
|
|
mark_slice (work);
|
|
gc_message (0x02, "!", 0);
|
|
}else{
|
|
long work = (long) (p * stat_heap_size) + Margin;
|
|
Assert (gc_phase == Phase_sweep);
|
|
sweep_slice (work);
|
|
gc_message (0x02, "$", 0);
|
|
}
|
|
|
|
if (gc_phase == Phase_idle) compact_heap_maybe ();
|
|
|
|
stat_major_words += allocated_words;
|
|
allocated_words = 0;
|
|
extra_heap_memory = 0.0;
|
|
}
|
|
|
|
/* The minor heap must be empty when this function is called;
|
|
the minor heap is empty when this function returns.
|
|
*/
|
|
/* This does not call compact_heap_maybe because the estimations of
|
|
free and live memory are only valid for a cycle done incrementally.
|
|
Besides, this function is called by compact_heap_maybe.
|
|
*/
|
|
void finish_major_cycle (void)
|
|
{
|
|
if (gc_phase == Phase_idle) start_cycle ();
|
|
if (gc_phase == Phase_mark) mark_slice (LONG_MAX);
|
|
Assert (gc_phase == Phase_sweep);
|
|
sweep_slice (LONG_MAX);
|
|
Assert (gc_phase == Phase_idle);
|
|
stat_major_words += allocated_words;
|
|
allocated_words = 0;
|
|
}
|
|
|
|
asize_t round_heap_chunk_size (asize_t request)
|
|
{ Assert (major_heap_increment >= Heap_chunk_min);
|
|
if (request < major_heap_increment){
|
|
Assert (major_heap_increment % Page_size == 0);
|
|
return major_heap_increment;
|
|
}else if (request <= Heap_chunk_max){
|
|
return ((request + Page_size - 1) >> Page_log) << Page_log;
|
|
}else{
|
|
raise_out_of_memory ();
|
|
/* not reached */ return 0;
|
|
}
|
|
}
|
|
|
|
void init_major_heap (asize_t heap_size)
|
|
{
|
|
asize_t i;
|
|
void *block;
|
|
asize_t page_table_size;
|
|
page_table_entry *page_table_block;
|
|
|
|
stat_heap_size = round_heap_chunk_size (heap_size);
|
|
Assert (stat_heap_size % Page_size == 0);
|
|
heap_start = aligned_malloc (stat_heap_size + sizeof (heap_chunk_head),
|
|
sizeof (heap_chunk_head), &block);
|
|
if (heap_start == NULL)
|
|
fatal_error ("Fatal error: not enough memory for the initial heap.\n");
|
|
heap_start += sizeof (heap_chunk_head);
|
|
Assert ((unsigned long) heap_start % Page_size == 0);
|
|
Chunk_size (heap_start) = stat_heap_size;
|
|
Chunk_next (heap_start) = NULL;
|
|
Chunk_block (heap_start) = block;
|
|
heap_end = heap_start + stat_heap_size;
|
|
Assert ((unsigned long) heap_end % Page_size == 0);
|
|
|
|
page_low = Page (heap_start);
|
|
page_high = Page (heap_end);
|
|
|
|
page_table_size = page_high - page_low;
|
|
page_table_block =
|
|
(page_table_entry *) malloc (page_table_size * sizeof (page_table_entry));
|
|
if (page_table_block == NULL){
|
|
fatal_error ("Fatal error: not enough memory for the initial heap.\n");
|
|
}
|
|
page_table = page_table_block - page_low;
|
|
for (i = Page (heap_start); i < Page (heap_end); i++){
|
|
page_table [i] = In_heap;
|
|
}
|
|
|
|
Hd_hp (heap_start) = Make_header (Wosize_bhsize (stat_heap_size), 0, Caml_blue);
|
|
fl_init_merge ();
|
|
fl_merge_block (Bp_hp (heap_start));
|
|
gc_phase = Phase_idle;
|
|
gray_vals_size = 2048;
|
|
gray_vals = (value *) malloc (gray_vals_size * sizeof (value));
|
|
if (gray_vals == NULL)
|
|
fatal_error ("Fatal error: not enough memory for the initial heap.\n");
|
|
gray_vals_cur = gray_vals;
|
|
gray_vals_end = gray_vals + gray_vals_size;
|
|
heap_is_pure = 1;
|
|
allocated_words = 0;
|
|
extra_heap_memory = 0.0;
|
|
}
|