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gecko-dev/gc/boehm/alloc.c

903 строки
26 KiB
C
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First Checked In.
1999-09-30 06:59:32 +04:00
/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
* Copyright (c) 1998 by Silicon Graphics. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*
*/
# include "gc_priv.h"
# include <stdio.h>
# ifndef MACOS
# include <signal.h>
# include <sys/types.h>
# endif
/*
* Separate free lists are maintained for different sized objects
* up to MAXOBJSZ.
* The call GC_allocobj(i,k) ensures that the freelist for
* kind k objects of size i points to a non-empty
* free list. It returns a pointer to the first entry on the free list.
* In a single-threaded world, GC_allocobj may be called to allocate
* an object of (small) size i as follows:
*
* opp = &(GC_objfreelist[i]);
* if (*opp == 0) GC_allocobj(i, NORMAL);
* ptr = *opp;
* *opp = obj_link(ptr);
*
* Note that this is very fast if the free list is non-empty; it should
* only involve the execution of 4 or 5 simple instructions.
* All composite objects on freelists are cleared, except for
* their first word.
*/
/*
* The allocator uses GC_allochblk to allocate large chunks of objects.
* These chunks all start on addresses which are multiples of
* HBLKSZ. Each allocated chunk has an associated header,
* which can be located quickly based on the address of the chunk.
* (See headers.c for details.)
* This makes it possible to check quickly whether an
* arbitrary address corresponds to an object administered by the
* allocator.
*/
word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */
word GC_gc_no = 0;
#ifndef SMALL_CONFIG
int GC_incremental = 0; /* By default, stop the world. */
#endif
int GC_full_freq = 4; /* Every 5th collection is a full */
/* collection. */
char * GC_copyright[] =
{"Copyright 1988,1989 Hans-J. Boehm and Alan J. Demers ",
"Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",
"Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",
"THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",
" EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",
"See source code for details." };
# include "version.h"
/* some more variables */
extern signed_word GC_mem_found; /* Number of reclaimed longwords */
/* after garbage collection */
GC_bool GC_dont_expand = 0;
word GC_free_space_divisor = 4;
extern GC_bool GC_collection_in_progress();
/* Collection is in progress, or was abandoned. */
int GC_never_stop_func GC_PROTO((void)) { return(0); }
CLOCK_TYPE GC_start_time; /* Time at which we stopped world. */
/* used only in GC_timeout_stop_func. */
int GC_n_attempts = 0; /* Number of attempts at finishing */
/* collection within TIME_LIMIT */
#ifdef SMALL_CONFIG
# define GC_timeout_stop_func GC_never_stop_func
#else
int GC_timeout_stop_func GC_PROTO((void))
{
CLOCK_TYPE current_time;
static unsigned count = 0;
unsigned long time_diff;
if ((count++ & 3) != 0) return(0);
GET_TIME(current_time);
time_diff = MS_TIME_DIFF(current_time,GC_start_time);
if (time_diff >= TIME_LIMIT) {
# ifdef PRINTSTATS
GC_printf0("Abandoning stopped marking after ");
GC_printf1("%lu msecs", (unsigned long)time_diff);
GC_printf1("(attempt %d)\n", (unsigned long) GC_n_attempts);
# endif
return(1);
}
return(0);
}
#endif /* !SMALL_CONFIG */
/* Return the minimum number of words that must be allocated between */
/* collections to amortize the collection cost. */
static word min_words_allocd()
{
# ifdef THREADS
/* We punt, for now. */
register signed_word stack_size = 10000;
# else
int dummy;
register signed_word stack_size = (ptr_t)(&dummy) - GC_stackbottom;
# endif
register word total_root_size; /* includes double stack size, */
/* since the stack is expensive */
/* to scan. */
if (stack_size < 0) stack_size = -stack_size;
total_root_size = 2 * stack_size + GC_root_size;
if (GC_incremental) {
return(BYTES_TO_WORDS(GC_heapsize + total_root_size)
/ (2 * GC_free_space_divisor));
} else {
return(BYTES_TO_WORDS(GC_heapsize + total_root_size)
/ GC_free_space_divisor);
}
}
/* Return the number of words allocated, adjusted for explicit storage */
/* management, etc.. This number is used in deciding when to trigger */
/* collections. */
word GC_adj_words_allocd()
{
register signed_word result;
register signed_word expl_managed =
BYTES_TO_WORDS((long)GC_non_gc_bytes
- (long)GC_non_gc_bytes_at_gc);
/* Don't count what was explicitly freed, or newly allocated for */
/* explicit management. Note that deallocating an explicitly */
/* managed object should not alter result, assuming the client */
/* is playing by the rules. */
result = (signed_word)GC_words_allocd
- (signed_word)GC_mem_freed - expl_managed;
if (result > (signed_word)GC_words_allocd) {
result = GC_words_allocd;
/* probably client bug or unfortunate scheduling */
}
result += GC_words_finalized;
/* We count objects enqueued for finalization as though they */
/* had been reallocated this round. Finalization is user */
/* visible progress. And if we don't count this, we have */
/* stability problems for programs that finalize all objects. */
result += GC_words_wasted;
/* This doesn't reflect useful work. But if there is lots of */
/* new fragmentation, the same is probably true of the heap, */
/* and the collection will be correspondingly cheaper. */
if (result < (signed_word)(GC_words_allocd >> 3)) {
/* Always count at least 1/8 of the allocations. We don't want */
/* to collect too infrequently, since that would inhibit */
/* coalescing of free storage blocks. */
/* This also makes us partially robust against client bugs. */
return(GC_words_allocd >> 3);
} else {
return(result);
}
}
/* Clear up a few frames worth of garbage left at the top of the stack. */
/* This is used to prevent us from accidentally treating garbade left */
/* on the stack by other parts of the collector as roots. This */
/* differs from the code in misc.c, which actually tries to keep the */
/* stack clear of long-lived, client-generated garbage. */
void GC_clear_a_few_frames()
{
# define NWORDS 64
word frames[NWORDS];
register int i;
for (i = 0; i < NWORDS; i++) frames[i] = 0;
}
/* Have we allocated enough to amortize a collection? */
GC_bool GC_should_collect()
{
return(GC_adj_words_allocd() >= min_words_allocd());
}
void GC_notify_full_gc()
{
if (GC_start_call_back != (void (*)())0) {
(*GC_start_call_back)();
}
}
/*
* Initiate a garbage collection if appropriate.
* Choose judiciously
* between partial, full, and stop-world collections.
* Assumes lock held, signals disabled.
*/
void GC_maybe_gc()
{
static int n_partial_gcs = 0;
GC_bool is_full_gc = FALSE;
if (GC_should_collect()) {
if (!GC_incremental) {
GC_notify_full_gc();
GC_gcollect_inner();
n_partial_gcs = 0;
return;
} else if (n_partial_gcs >= GC_full_freq) {
# ifdef PRINTSTATS
GC_printf2(
"***>Full mark for collection %lu after %ld allocd bytes\n",
(unsigned long) GC_gc_no+1,
(long)WORDS_TO_BYTES(GC_words_allocd));
# endif
GC_promote_black_lists();
(void)GC_reclaim_all((GC_stop_func)0, TRUE);
GC_clear_marks();
n_partial_gcs = 0;
GC_notify_full_gc();
is_full_gc = TRUE;
} else {
n_partial_gcs++;
}
/* We try to mark with the world stopped. */
/* If we run out of time, this turns into */
/* incremental marking. */
GET_TIME(GC_start_time);
if (GC_stopped_mark(GC_timeout_stop_func)) {
# ifdef SAVE_CALL_CHAIN
GC_save_callers(GC_last_stack);
# endif
GC_finish_collection();
} else {
if (!is_full_gc) {
/* Count this as the first attempt */
GC_n_attempts++;
}
}
}
}
/*
* Stop the world garbage collection. Assumes lock held, signals disabled.
* If stop_func is not GC_never_stop_func, then abort if stop_func returns TRUE.
*/
GC_bool GC_try_to_collect_inner(stop_func)
GC_stop_func stop_func;
{
if (GC_incremental && GC_collection_in_progress()) {
# ifdef PRINTSTATS
GC_printf0(
"GC_try_to_collect_inner: finishing collection in progress\n");
# endif /* PRINTSTATS */
/* Just finish collection already in progress. */
while(GC_collection_in_progress()) {
if (stop_func()) return(FALSE);
GC_collect_a_little_inner(1);
}
}
# ifdef PRINTSTATS
GC_printf2(
"Initiating full world-stop collection %lu after %ld allocd bytes\n",
(unsigned long) GC_gc_no+1,
(long)WORDS_TO_BYTES(GC_words_allocd));
# endif
GC_promote_black_lists();
/* Make sure all blocks have been reclaimed, so sweep routines */
/* don't see cleared mark bits. */
/* If we're guaranteed to finish, then this is unnecessary. */
if (stop_func != GC_never_stop_func
&& !GC_reclaim_all(stop_func, FALSE)) {
/* Aborted. So far everything is still consistent. */
return(FALSE);
}
GC_invalidate_mark_state(); /* Flush mark stack. */
GC_clear_marks();
# ifdef SAVE_CALL_CHAIN
GC_save_callers(GC_last_stack);
# endif
if (!GC_stopped_mark(stop_func)) {
if (!GC_incremental) {
/* We're partially done and have no way to complete or use */
/* current work. Reestablish invariants as cheaply as */
/* possible. */
GC_invalidate_mark_state();
GC_unpromote_black_lists();
} /* else we claim the world is already still consistent. We'll */
/* finish incrementally. */
return(FALSE);
}
GC_finish_collection();
return(TRUE);
}
/*
* Perform n units of garbage collection work. A unit is intended to touch
* roughly GC_RATE pages. Every once in a while, we do more than that.
* This needa to be a fairly large number with our current incremental
* GC strategy, since otherwise we allocate too much during GC, and the
* cleanup gets expensive.
*/
# define GC_RATE 10
# define MAX_PRIOR_ATTEMPTS 1
/* Maximum number of prior attempts at world stop marking */
/* A value of 1 means that we finish the seconf time, no matter */
/* how long it takes. Doesn't count the initial root scan */
/* for a full GC. */
int GC_deficit = 0; /* The number of extra calls to GC_mark_some */
/* that we have made. */
void GC_collect_a_little_inner(n)
int n;
{
register int i;
if (GC_incremental && GC_collection_in_progress()) {
for (i = GC_deficit; i < GC_RATE*n; i++) {
if (GC_mark_some((ptr_t)0)) {
/* Need to finish a collection */
# ifdef SAVE_CALL_CHAIN
GC_save_callers(GC_last_stack);
# endif
if (GC_n_attempts < MAX_PRIOR_ATTEMPTS) {
GET_TIME(GC_start_time);
if (!GC_stopped_mark(GC_timeout_stop_func)) {
GC_n_attempts++;
break;
}
} else {
(void)GC_stopped_mark(GC_never_stop_func);
}
GC_finish_collection();
break;
}
}
if (GC_deficit > 0) GC_deficit -= GC_RATE*n;
if (GC_deficit < 0) GC_deficit = 0;
} else {
GC_maybe_gc();
}
}
int GC_collect_a_little GC_PROTO(())
{
int result;
DCL_LOCK_STATE;
DISABLE_SIGNALS();
LOCK();
GC_collect_a_little_inner(1);
result = (int)GC_collection_in_progress();
UNLOCK();
ENABLE_SIGNALS();
return(result);
}
/*
* Assumes lock is held, signals are disabled.
* We stop the world.
* If stop_func() ever returns TRUE, we may fail and return FALSE.
* Increment GC_gc_no if we succeed.
*/
GC_bool GC_stopped_mark(stop_func)
GC_stop_func stop_func;
{
register int i;
int dummy;
# ifdef PRINTSTATS
CLOCK_TYPE start_time, current_time;
# endif
STOP_WORLD();
# ifdef PRINTSTATS
GET_TIME(start_time);
GC_printf1("--> Marking for collection %lu ",
(unsigned long) GC_gc_no + 1);
GC_printf2("after %lu allocd bytes + %lu wasted bytes\n",
(unsigned long) WORDS_TO_BYTES(GC_words_allocd),
(unsigned long) WORDS_TO_BYTES(GC_words_wasted));
# endif
/* Mark from all roots. */
/* Minimize junk left in my registers and on the stack */
GC_clear_a_few_frames();
GC_noop(0,0,0,0,0,0);
GC_initiate_gc();
for(i = 0;;i++) {
if ((*stop_func)()) {
# ifdef PRINTSTATS
GC_printf0("Abandoned stopped marking after ");
GC_printf1("%lu iterations\n",
(unsigned long)i);
# endif
GC_deficit = i; /* Give the mutator a chance. */
START_WORLD();
return(FALSE);
}
if (GC_mark_some((ptr_t)(&dummy))) break;
}
GC_gc_no++;
# ifdef PRINTSTATS
GC_printf2("Collection %lu reclaimed %ld bytes",
(unsigned long) GC_gc_no - 1,
(long)WORDS_TO_BYTES(GC_mem_found));
GC_printf1(" ---> heapsize = %lu bytes\n",
(unsigned long) GC_heapsize);
/* Printf arguments may be pushed in funny places. Clear the */
/* space. */
GC_printf0("");
# endif
/* Check all debugged objects for consistency */
if (GC_debugging_started) {
(*GC_check_heap)();
}
# ifdef PRINTTIMES
GET_TIME(current_time);
GC_printf1("World-stopped marking took %lu msecs\n",
MS_TIME_DIFF(current_time,start_time));
# endif
START_WORLD();
return(TRUE);
}
/* Finish up a collection. Assumes lock is held, signals are disabled, */
/* but the world is otherwise running. */
void GC_finish_collection()
{
# ifdef PRINTTIMES
CLOCK_TYPE start_time;
CLOCK_TYPE finalize_time;
CLOCK_TYPE done_time;
GET_TIME(start_time);
finalize_time = start_time;
# endif
# ifdef GATHERSTATS
GC_mem_found = 0;
# endif
# ifdef FIND_LEAK
/* Mark all objects on the free list. All objects should be */
/* marked when we're done. */
{
register word size; /* current object size */
register ptr_t p; /* pointer to current object */
register struct hblk * h; /* pointer to block containing *p */
register hdr * hhdr;
register int word_no; /* "index" of *p in *q */
int kind;
for (kind = 0; kind < GC_n_kinds; kind++) {
for (size = 1; size <= MAXOBJSZ; size++) {
for (p= GC_obj_kinds[kind].ok_freelist[size];
p != 0; p=obj_link(p)){
h = HBLKPTR(p);
hhdr = HDR(h);
word_no = (((word *)p) - ((word *)h));
set_mark_bit_from_hdr(hhdr, word_no);
}
}
}
}
/* Check that everything is marked */
GC_start_reclaim(TRUE);
# else
GC_finalize();
# ifdef STUBBORN_ALLOC
GC_clean_changing_list();
# endif
# ifdef PRINTTIMES
GET_TIME(finalize_time);
# endif
/* Clear free list mark bits, in case they got accidentally marked */
/* Note: HBLKPTR(p) == pointer to head of block containing *p */
/* Also subtract memory remaining from GC_mem_found count. */
/* Note that composite objects on free list are cleared. */
/* Thus accidentally marking a free list is not a problem; only */
/* objects on the list itself will be marked, and that's fixed here. */
{
register word size; /* current object size */
register ptr_t p; /* pointer to current object */
register struct hblk * h; /* pointer to block containing *p */
register hdr * hhdr;
register int word_no; /* "index" of *p in *q */
int kind;
for (kind = 0; kind < GC_n_kinds; kind++) {
for (size = 1; size <= MAXOBJSZ; size++) {
for (p= GC_obj_kinds[kind].ok_freelist[size];
p != 0; p=obj_link(p)){
h = HBLKPTR(p);
hhdr = HDR(h);
word_no = (((word *)p) - ((word *)h));
clear_mark_bit_from_hdr(hhdr, word_no);
# ifdef GATHERSTATS
GC_mem_found -= size;
# endif
}
}
}
}
# ifdef PRINTSTATS
GC_printf1("Bytes recovered before sweep - f.l. count = %ld\n",
(long)WORDS_TO_BYTES(GC_mem_found));
# endif
/* Reconstruct free lists to contain everything not marked */
GC_start_reclaim(FALSE);
# endif /* !FIND_LEAK */
# ifdef PRINTSTATS
GC_printf2(
"Immediately reclaimed %ld bytes in heap of size %lu bytes\n",
(long)WORDS_TO_BYTES(GC_mem_found),
(unsigned long)GC_heapsize);
GC_printf2("%lu (atomic) + %lu (composite) collectable bytes in use\n",
(unsigned long)WORDS_TO_BYTES(GC_atomic_in_use),
(unsigned long)WORDS_TO_BYTES(GC_composite_in_use));
# endif
GC_n_attempts = 0;
/* Reset or increment counters for next cycle */
GC_words_allocd_before_gc += GC_words_allocd;
GC_non_gc_bytes_at_gc = GC_non_gc_bytes;
GC_words_allocd = 0;
GC_words_wasted = 0;
GC_mem_freed = 0;
# ifdef PRINTTIMES
GET_TIME(done_time);
GC_printf2("Finalize + initiate sweep took %lu + %lu msecs\n",
MS_TIME_DIFF(finalize_time,start_time),
MS_TIME_DIFF(done_time,finalize_time));
# endif
}
/* Externally callable routine to invoke full, stop-world collection */
# if defined(__STDC__) || defined(__cplusplus)
int GC_try_to_collect(GC_stop_func stop_func)
# else
int GC_try_to_collect(stop_func)
GC_stop_func stop_func;
# endif
{
int result;
DCL_LOCK_STATE;
GC_INVOKE_FINALIZERS();
DISABLE_SIGNALS();
LOCK();
ENTER_GC();
if (!GC_is_initialized) GC_init_inner();
/* Minimize junk left in my registers */
GC_noop(0,0,0,0,0,0);
result = (int)GC_try_to_collect_inner(stop_func);
EXIT_GC();
UNLOCK();
ENABLE_SIGNALS();
if(result) GC_INVOKE_FINALIZERS();
return(result);
}
void GC_gcollect GC_PROTO(())
{
GC_notify_full_gc();
(void)GC_try_to_collect(GC_never_stop_func);
}
word GC_n_heap_sects = 0; /* Number of sections currently in heap. */
/*
* Use the chunk of memory starting at p of syze bytes as part of the heap.
* Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE.
*/
void GC_add_to_heap(p, bytes)
struct hblk *p;
word bytes;
{
word words;
if (GC_n_heap_sects >= MAX_HEAP_SECTS) {
ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS");
}
if (!GC_install_header(p)) {
/* This is extremely unlikely. Can't add it. This will */
/* almost certainly result in a 0 return from the allocator, */
/* which is entirely appropriate. */
return;
}
GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p;
GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes;
GC_n_heap_sects++;
words = BYTES_TO_WORDS(bytes - HDR_BYTES);
HDR(p) -> hb_sz = words;
GC_freehblk(p);
GC_heapsize += bytes;
if ((ptr_t)p <= GC_least_plausible_heap_addr
|| GC_least_plausible_heap_addr == 0) {
GC_least_plausible_heap_addr = (ptr_t)p - sizeof(word);
/* Making it a little smaller than necessary prevents */
/* us from getting a false hit from the variable */
/* itself. There's some unintentional reflection */
/* here. */
}
if ((ptr_t)p + bytes >= GC_greatest_plausible_heap_addr) {
GC_greatest_plausible_heap_addr = (ptr_t)p + bytes;
}
}
#ifdef PRESERVE_LAST
GC_bool GC_protect_last_block = FALSE;
GC_bool GC_in_last_heap_sect(p)
ptr_t p;
{
struct HeapSect * last_heap_sect;
ptr_t start;
ptr_t end;
if (!GC_protect_last_block) return FALSE;
last_heap_sect = &(GC_heap_sects[GC_n_heap_sects-1]);
start = last_heap_sect -> hs_start;
if (p < start) return FALSE;
end = start + last_heap_sect -> hs_bytes;
if (p >= end) return FALSE;
return TRUE;
}
#endif
# if !defined(NO_DEBUGGING)
void GC_print_heap_sects()
{
register unsigned i;
GC_printf1("Total heap size: %lu\n", (unsigned long) GC_heapsize);
for (i = 0; i < GC_n_heap_sects; i++) {
unsigned long start = (unsigned long) GC_heap_sects[i].hs_start;
unsigned long len = (unsigned long) GC_heap_sects[i].hs_bytes;
struct hblk *h;
unsigned nbl = 0;
GC_printf3("Section %ld from 0x%lx to 0x%lx ", (unsigned long)i,
start, (unsigned long)(start + len));
for (h = (struct hblk *)start; h < (struct hblk *)(start + len); h++) {
if (GC_is_black_listed(h, HBLKSIZE)) nbl++;
}
GC_printf2("%lu/%lu blacklisted\n", (unsigned long)nbl,
(unsigned long)(len/HBLKSIZE));
}
}
# endif
ptr_t GC_least_plausible_heap_addr = (ptr_t)ONES;
ptr_t GC_greatest_plausible_heap_addr = 0;
ptr_t GC_max(x,y)
ptr_t x, y;
{
return(x > y? x : y);
}
ptr_t GC_min(x,y)
ptr_t x, y;
{
return(x < y? x : y);
}
# if defined(__STDC__) || defined(__cplusplus)
void GC_set_max_heap_size(GC_word n)
# else
void GC_set_max_heap_size(n)
GC_word n;
# endif
{
GC_max_heapsize = n;
}
GC_word GC_max_retries = 0;
/*
* this explicitly increases the size of the heap. It is used
* internally, but may also be invoked from GC_expand_hp by the user.
* The argument is in units of HBLKSIZE.
* Tiny values of n are rounded up.
* Returns FALSE on failure.
*/
GC_bool GC_expand_hp_inner(n)
word n;
{
word bytes;
struct hblk * space;
word expansion_slop; /* Number of bytes by which we expect the */
/* heap to expand soon. */
if (n < MINHINCR) n = MINHINCR;
bytes = n * HBLKSIZE;
/* Make sure bytes is a multiple of GC_page_size */
{
word mask = GC_page_size - 1;
bytes += mask;
bytes &= ~mask;
}
if (GC_max_heapsize != 0 && GC_heapsize + bytes > GC_max_heapsize) {
/* Exceeded self-imposed limit */
return(FALSE);
}
space = GET_MEM(bytes);
if( space == 0 ) {
return(FALSE);
}
# ifdef PRINTSTATS
GC_printf2("Increasing heap size by %lu after %lu allocated bytes\n",
(unsigned long)bytes,
(unsigned long)WORDS_TO_BYTES(GC_words_allocd));
# ifdef UNDEFINED
GC_printf1("Root size = %lu\n", GC_root_size);
GC_print_block_list(); GC_print_hblkfreelist();
GC_printf0("\n");
# endif
# endif
expansion_slop = 8 * WORDS_TO_BYTES(min_words_allocd());
if (5 * HBLKSIZE * MAXHINCR > expansion_slop) {
expansion_slop = 5 * HBLKSIZE * MAXHINCR;
}
if (GC_last_heap_addr == 0 && !((word)space & SIGNB)
|| GC_last_heap_addr != 0 && GC_last_heap_addr < (ptr_t)space) {
/* Assume the heap is growing up */
GC_greatest_plausible_heap_addr =
GC_max(GC_greatest_plausible_heap_addr,
(ptr_t)space + bytes + expansion_slop);
} else {
/* Heap is growing down */
GC_least_plausible_heap_addr =
GC_min(GC_least_plausible_heap_addr,
(ptr_t)space - expansion_slop);
}
GC_prev_heap_addr = GC_last_heap_addr;
GC_last_heap_addr = (ptr_t)space;
GC_add_to_heap(space, bytes);
return(TRUE);
}
/* Really returns a bool, but it's externally visible, so that's clumsy. */
/* Arguments is in bytes. */
# if defined(__STDC__) || defined(__cplusplus)
int GC_expand_hp(size_t bytes)
# else
int GC_expand_hp(bytes)
size_t bytes;
# endif
{
int result;
DCL_LOCK_STATE;
DISABLE_SIGNALS();
LOCK();
if (!GC_is_initialized) GC_init_inner();
result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes));
# ifdef PRESERVE_LAST
if (result) GC_protect_last_block = FALSE;
# endif
UNLOCK();
ENABLE_SIGNALS();
return(result);
}
unsigned GC_fail_count = 0;
/* How many consecutive GC/expansion failures? */
/* Reset by GC_allochblk. */
GC_bool GC_collect_or_expand(needed_blocks, ignore_off_page)
word needed_blocks;
GC_bool ignore_off_page;
{
if (!GC_incremental && !GC_dont_gc && GC_should_collect()) {
GC_notify_full_gc();
GC_gcollect_inner();
} else {
word blocks_to_get = GC_heapsize/(HBLKSIZE*GC_free_space_divisor)
+ needed_blocks;
if (blocks_to_get > MAXHINCR) {
word slop;
if (ignore_off_page) {
slop = 4;
} else {
slop = 2*divHBLKSZ(BL_LIMIT);
if (slop > needed_blocks) slop = needed_blocks;
}
if (needed_blocks + slop > MAXHINCR) {
blocks_to_get = needed_blocks + slop;
} else {
blocks_to_get = MAXHINCR;
}
}
if (!GC_expand_hp_inner(blocks_to_get)
&& !GC_expand_hp_inner(needed_blocks)) {
if (GC_fail_count++ < GC_max_retries) {
WARN("Out of Memory! Trying to continue ...\n", 0);
GC_notify_full_gc();
GC_gcollect_inner();
} else {
WARN("Out of Memory! Returning NIL!\n", 0);
return(FALSE);
}
} else {
# ifdef PRINTSTATS
if (GC_fail_count) {
GC_printf0("Memory available again ...\n");
}
# endif
# ifdef PRESERVE_LAST
if (needed_blocks > 1) GC_protect_last_block = TRUE;
/* We were forced to expand the heap as the result */
/* of a large block allocation. Avoid breaking up */
/* new block into small pieces. */
# endif
}
}
return(TRUE);
}
/*
* Make sure the object free list for sz is not empty.
* Return a pointer to the first object on the free list.
* The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER.
* Assumes we hold the allocator lock and signals are disabled.
*
*/
ptr_t GC_allocobj(sz, kind)
word sz;
int kind;
{
register ptr_t * flh = &(GC_obj_kinds[kind].ok_freelist[sz]);
if (sz == 0) return(0);
while (*flh == 0) {
ENTER_GC();
/* Do our share of marking work */
if(GC_incremental && !GC_dont_gc) GC_collect_a_little_inner(1);
/* Sweep blocks for objects of this size */
GC_continue_reclaim(sz, kind);
EXIT_GC();
if (*flh == 0) {
GC_new_hblk(sz, kind);
}
if (*flh == 0) {
ENTER_GC();
if (!GC_collect_or_expand((word)1,FALSE)) {
EXIT_GC();
return(0);
}
EXIT_GC();
}
}
return(*flh);
}