2 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3 * Copyright (c) 1991-1996 by Xerox Corporation. All rights reserved.
4 * Copyright (c) 1998 by Silicon Graphics. All rights reserved.
5 * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
7 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 * Permission is hereby granted to use or copy this program
11 * for any purpose, provided the above notices are retained on all copies.
12 * Permission to modify the code and to distribute modified code is granted,
13 * provided the above notices are retained, and a notice that the code was
14 * modified is included with the above copyright notice.
19 # include "private/gc_priv.h"
22 # if !defined(MACOS) && !defined(MSWINCE)
24 # include <sys/types.h>
28 * Separate free lists are maintained for different sized objects
30 * The call GC_allocobj(i,k) ensures that the freelist for
31 * kind k objects of size i points to a non-empty
32 * free list. It returns a pointer to the first entry on the free list.
33 * In a single-threaded world, GC_allocobj may be called to allocate
34 * an object of (small) size i as follows:
36 * opp = &(GC_objfreelist[i]);
37 * if (*opp == 0) GC_allocobj(i, NORMAL);
39 * *opp = obj_link(ptr);
41 * Note that this is very fast if the free list is non-empty; it should
42 * only involve the execution of 4 or 5 simple instructions.
43 * All composite objects on freelists are cleared, except for
48 * The allocator uses GC_allochblk to allocate large chunks of objects.
49 * These chunks all start on addresses which are multiples of
50 * HBLKSZ. Each allocated chunk has an associated header,
51 * which can be located quickly based on the address of the chunk.
52 * (See headers.c for details.)
53 * This makes it possible to check quickly whether an
54 * arbitrary address corresponds to an object administered by the
58 word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */
63 int GC_incremental = 0; /* By default, stop the world. */
66 int GC_parallel = FALSE; /* By default, parallel GC is off. */
68 int GC_full_freq = 19; /* Every 20th collection is a full */
69 /* collection, whether we need it */
72 GC_bool GC_need_full_gc = FALSE;
73 /* Need full GC do to heap growth. */
76 GC_bool GC_world_stopped = FALSE;
77 # define IF_THREADS(x) x
79 # define IF_THREADS(x)
82 word GC_used_heap_size_after_full = 0;
84 char * GC_copyright[] =
85 {"Copyright 1988,1989 Hans-J. Boehm and Alan J. Demers ",
86 "Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",
87 "Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",
88 "Copyright (c) 1999-2001 by Hewlett-Packard Company. All rights reserved. ",
89 "THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",
90 " EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",
91 "See source code for details." };
95 /* some more variables */
97 extern signed_word GC_mem_found; /* Number of reclaimed longwords */
98 /* after garbage collection */
100 GC_bool GC_dont_expand = 0;
102 word GC_free_space_divisor = 3;
104 extern GC_bool GC_collection_in_progress();
105 /* Collection is in progress, or was abandoned. */
107 extern GC_bool GC_print_back_height;
109 int GC_never_stop_func GC_PROTO((void)) { return(0); }
111 unsigned long GC_time_limit = TIME_LIMIT;
113 CLOCK_TYPE GC_start_time; /* Time at which we stopped world. */
114 /* used only in GC_timeout_stop_func. */
116 int GC_n_attempts = 0; /* Number of attempts at finishing */
117 /* collection within GC_time_limit. */
119 #if defined(SMALL_CONFIG) || defined(NO_CLOCK)
120 # define GC_timeout_stop_func GC_never_stop_func
122 int GC_timeout_stop_func GC_PROTO((void))
124 CLOCK_TYPE current_time;
125 static unsigned count = 0;
126 unsigned long time_diff;
128 if ((count++ & 3) != 0) return(0);
129 GET_TIME(current_time);
130 time_diff = MS_TIME_DIFF(current_time,GC_start_time);
131 if (time_diff >= GC_time_limit) {
133 if (GC_print_stats) {
134 GC_printf0("Abandoning stopped marking after ");
135 GC_printf1("%lu msecs", (unsigned long)time_diff);
136 GC_printf1("(attempt %d)\n", (unsigned long) GC_n_attempts);
143 #endif /* !SMALL_CONFIG */
145 /* Return the minimum number of words that must be allocated between */
146 /* collections to amortize the collection cost. */
147 static word min_words_allocd()
150 /* We punt, for now. */
151 register signed_word stack_size = 10000;
154 register signed_word stack_size = (ptr_t)(&dummy) - GC_stackbottom;
156 word total_root_size; /* includes double stack size, */
157 /* since the stack is expensive */
159 word scan_size; /* Estimate of memory to be scanned */
160 /* during normal GC. */
162 if (stack_size < 0) stack_size = -stack_size;
163 total_root_size = 2 * stack_size + GC_root_size;
164 scan_size = BYTES_TO_WORDS(GC_heapsize - GC_large_free_bytes
165 + (GC_large_free_bytes >> 2)
166 /* use a bit more of large empty heap */
168 if (TRUE_INCREMENTAL) {
169 return scan_size / (2 * GC_free_space_divisor);
171 return scan_size / GC_free_space_divisor;
175 /* Return the number of words allocated, adjusted for explicit storage */
176 /* management, etc.. This number is used in deciding when to trigger */
178 word GC_adj_words_allocd()
180 register signed_word result;
181 register signed_word expl_managed =
182 BYTES_TO_WORDS((long)GC_non_gc_bytes
183 - (long)GC_non_gc_bytes_at_gc);
185 /* Don't count what was explicitly freed, or newly allocated for */
186 /* explicit management. Note that deallocating an explicitly */
187 /* managed object should not alter result, assuming the client */
188 /* is playing by the rules. */
189 result = (signed_word)GC_words_allocd
190 - (signed_word)GC_mem_freed
191 + (signed_word)GC_finalizer_mem_freed - expl_managed;
192 if (result > (signed_word)GC_words_allocd) {
193 result = GC_words_allocd;
194 /* probably client bug or unfortunate scheduling */
196 result += GC_words_finalized;
197 /* We count objects enqueued for finalization as though they */
198 /* had been reallocated this round. Finalization is user */
199 /* visible progress. And if we don't count this, we have */
200 /* stability problems for programs that finalize all objects. */
201 result += GC_words_wasted;
202 /* This doesn't reflect useful work. But if there is lots of */
203 /* new fragmentation, the same is probably true of the heap, */
204 /* and the collection will be correspondingly cheaper. */
205 if (result < (signed_word)(GC_words_allocd >> 3)) {
206 /* Always count at least 1/8 of the allocations. We don't want */
207 /* to collect too infrequently, since that would inhibit */
208 /* coalescing of free storage blocks. */
209 /* This also makes us partially robust against client bugs. */
210 return(GC_words_allocd >> 3);
217 /* Clear up a few frames worth of garbage left at the top of the stack. */
218 /* This is used to prevent us from accidentally treating garbade left */
219 /* on the stack by other parts of the collector as roots. This */
220 /* differs from the code in misc.c, which actually tries to keep the */
221 /* stack clear of long-lived, client-generated garbage. */
222 void GC_clear_a_few_frames()
228 for (i = 0; i < NWORDS; i++) frames[i] = 0;
231 /* Have we allocated enough to amortize a collection? */
232 GC_bool GC_should_collect()
234 return(GC_adj_words_allocd() >= min_words_allocd());
238 void GC_notify_full_gc()
240 if (GC_start_call_back != (void (*) GC_PROTO((void)))0) {
241 (*GC_start_call_back)();
245 GC_bool GC_is_full_gc = FALSE;
248 * Initiate a garbage collection if appropriate.
250 * between partial, full, and stop-world collections.
251 * Assumes lock held, signals disabled.
255 static int n_partial_gcs = 0;
257 if (GC_should_collect()) {
258 if (!GC_incremental) {
263 # ifdef PARALLEL_MARK
264 GC_wait_for_reclaim();
266 if (GC_need_full_gc || n_partial_gcs >= GC_full_freq) {
268 if (GC_print_stats) {
270 "***>Full mark for collection %lu after %ld allocd bytes\n",
271 (unsigned long) GC_gc_no+1,
272 (long)WORDS_TO_BYTES(GC_words_allocd));
275 GC_promote_black_lists();
276 (void)GC_reclaim_all((GC_stop_func)0, TRUE);
280 GC_is_full_gc = TRUE;
285 /* We try to mark with the world stopped. */
286 /* If we run out of time, this turns into */
287 /* incremental marking. */
289 if (GC_time_limit != GC_TIME_UNLIMITED) { GET_TIME(GC_start_time); }
291 if (GC_stopped_mark(GC_time_limit == GC_TIME_UNLIMITED?
292 GC_never_stop_func : GC_timeout_stop_func)) {
293 # ifdef SAVE_CALL_CHAIN
294 GC_save_callers(GC_last_stack);
296 GC_finish_collection();
298 if (!GC_is_full_gc) {
299 /* Count this as the first attempt */
308 * Stop the world garbage collection. Assumes lock held, signals disabled.
309 * If stop_func is not GC_never_stop_func, then abort if stop_func returns TRUE.
310 * Return TRUE if we successfully completed the collection.
312 GC_bool GC_try_to_collect_inner(stop_func)
313 GC_stop_func stop_func;
316 CLOCK_TYPE start_time, current_time;
318 if (GC_dont_gc) return FALSE;
319 if (GC_incremental && GC_collection_in_progress()) {
321 if (GC_print_stats) {
323 "GC_try_to_collect_inner: finishing collection in progress\n");
325 # endif /* CONDPRINT */
326 /* Just finish collection already in progress. */
327 while(GC_collection_in_progress()) {
328 if (stop_func()) return(FALSE);
329 GC_collect_a_little_inner(1);
332 if (stop_func == GC_never_stop_func) GC_notify_full_gc();
334 if (GC_print_stats) {
335 if (GC_print_stats) GET_TIME(start_time);
337 "Initiating full world-stop collection %lu after %ld allocd bytes\n",
338 (unsigned long) GC_gc_no+1,
339 (long)WORDS_TO_BYTES(GC_words_allocd));
342 GC_promote_black_lists();
343 /* Make sure all blocks have been reclaimed, so sweep routines */
344 /* don't see cleared mark bits. */
345 /* If we're guaranteed to finish, then this is unnecessary. */
346 /* In the find_leak case, we have to finish to guarantee that */
347 /* previously unmarked objects are not reported as leaks. */
348 # ifdef PARALLEL_MARK
349 GC_wait_for_reclaim();
351 if ((GC_find_leak || stop_func != GC_never_stop_func)
352 && !GC_reclaim_all(stop_func, FALSE)) {
353 /* Aborted. So far everything is still consistent. */
356 GC_invalidate_mark_state(); /* Flush mark stack. */
358 # ifdef SAVE_CALL_CHAIN
359 GC_save_callers(GC_last_stack);
361 GC_is_full_gc = TRUE;
362 if (!GC_stopped_mark(stop_func)) {
363 if (!GC_incremental) {
364 /* We're partially done and have no way to complete or use */
365 /* current work. Reestablish invariants as cheaply as */
367 GC_invalidate_mark_state();
368 GC_unpromote_black_lists();
369 } /* else we claim the world is already still consistent. We'll */
370 /* finish incrementally. */
373 GC_finish_collection();
374 # if defined(CONDPRINT)
375 if (GC_print_stats) {
376 GET_TIME(current_time);
377 GC_printf1("Complete collection took %lu msecs\n",
378 MS_TIME_DIFF(current_time,start_time));
387 * Perform n units of garbage collection work. A unit is intended to touch
388 * roughly GC_RATE pages. Every once in a while, we do more than that.
389 * This needa to be a fairly large number with our current incremental
390 * GC strategy, since otherwise we allocate too much during GC, and the
391 * cleanup gets expensive.
394 # define MAX_PRIOR_ATTEMPTS 1
395 /* Maximum number of prior attempts at world stop marking */
396 /* A value of 1 means that we finish the second time, no matter */
397 /* how long it takes. Doesn't count the initial root scan */
400 int GC_deficit = 0; /* The number of extra calls to GC_mark_some */
401 /* that we have made. */
403 void GC_collect_a_little_inner(n)
408 if (GC_dont_gc) return;
409 if (GC_incremental && GC_collection_in_progress()) {
410 for (i = GC_deficit; i < GC_RATE*n; i++) {
411 if (GC_mark_some((ptr_t)0)) {
412 /* Need to finish a collection */
413 # ifdef SAVE_CALL_CHAIN
414 GC_save_callers(GC_last_stack);
416 # ifdef PARALLEL_MARK
417 GC_wait_for_reclaim();
419 if (GC_n_attempts < MAX_PRIOR_ATTEMPTS
420 && GC_time_limit != GC_TIME_UNLIMITED) {
421 GET_TIME(GC_start_time);
422 if (!GC_stopped_mark(GC_timeout_stop_func)) {
427 (void)GC_stopped_mark(GC_never_stop_func);
429 GC_finish_collection();
433 if (GC_deficit > 0) GC_deficit -= GC_RATE*n;
434 if (GC_deficit < 0) GC_deficit = 0;
440 int GC_collect_a_little GC_PROTO(())
447 GC_collect_a_little_inner(1);
448 result = (int)GC_collection_in_progress();
451 if (!result && GC_debugging_started) GC_print_all_smashed();
456 * Assumes lock is held, signals are disabled.
458 * If stop_func() ever returns TRUE, we may fail and return FALSE.
459 * Increment GC_gc_no if we succeed.
461 GC_bool GC_stopped_mark(stop_func)
462 GC_stop_func stop_func;
466 # if defined(PRINTTIMES) || defined(CONDPRINT)
467 CLOCK_TYPE start_time, current_time;
471 GET_TIME(start_time);
473 # if defined(CONDPRINT) && !defined(PRINTTIMES)
474 if (GC_print_stats) GET_TIME(start_time);
476 # if defined(REGISTER_LIBRARIES_EARLY)
477 GC_cond_register_dynamic_libraries();
480 IF_THREADS(GC_world_stopped = TRUE);
482 if (GC_print_stats) {
483 GC_printf1("--> Marking for collection %lu ",
484 (unsigned long) GC_gc_no + 1);
485 GC_printf2("after %lu allocd bytes + %lu wasted bytes\n",
486 (unsigned long) WORDS_TO_BYTES(GC_words_allocd),
487 (unsigned long) WORDS_TO_BYTES(GC_words_wasted));
490 # ifdef MAKE_BACK_GRAPH
491 if (GC_print_back_height) {
492 GC_build_back_graph();
496 /* Mark from all roots. */
497 /* Minimize junk left in my registers and on the stack */
498 GC_clear_a_few_frames();
499 GC_noop(0,0,0,0,0,0);
502 if ((*stop_func)()) {
504 if (GC_print_stats) {
505 GC_printf0("Abandoned stopped marking after ");
506 GC_printf1("%lu iterations\n",
510 GC_deficit = i; /* Give the mutator a chance. */
511 IF_THREADS(GC_world_stopped = FALSE);
515 if (GC_mark_some((ptr_t)(&dummy))) break;
520 GC_printf2("Collection %lu reclaimed %ld bytes",
521 (unsigned long) GC_gc_no - 1,
522 (long)WORDS_TO_BYTES(GC_mem_found));
525 if (GC_print_stats) {
526 GC_printf1("Collection %lu finished", (unsigned long) GC_gc_no - 1);
529 # endif /* !PRINTSTATS */
531 if (GC_print_stats) {
532 GC_printf1(" ---> heapsize = %lu bytes\n",
533 (unsigned long) GC_heapsize);
534 /* Printf arguments may be pushed in funny places. Clear the */
538 # endif /* CONDPRINT */
540 /* Check all debugged objects for consistency */
541 if (GC_debugging_started) {
545 IF_THREADS(GC_world_stopped = FALSE);
548 GET_TIME(current_time);
549 GC_printf1("World-stopped marking took %lu msecs\n",
550 MS_TIME_DIFF(current_time,start_time));
553 if (GC_print_stats) {
554 GET_TIME(current_time);
555 GC_printf1("World-stopped marking took %lu msecs\n",
556 MS_TIME_DIFF(current_time,start_time));
563 /* Set all mark bits for the free list whose first entry is q */
565 void GC_set_fl_marks(ptr_t q)
567 void GC_set_fl_marks(q)
572 struct hblk * h, * last_h = 0;
576 for (p = q; p != 0; p = obj_link(p)){
582 word_no = (((word *)p) - ((word *)h));
583 set_mark_bit_from_hdr(hhdr, word_no);
587 /* Clear all mark bits for the free list whose first entry is q */
588 /* Decrement GC_mem_found by number of words on free list. */
590 void GC_clear_fl_marks(ptr_t q)
592 void GC_clear_fl_marks(q)
597 struct hblk * h, * last_h = 0;
601 for (p = q; p != 0; p = obj_link(p)){
607 word_no = (((word *)p) - ((word *)h));
608 clear_mark_bit_from_hdr(hhdr, word_no);
610 GC_mem_found -= hhdr -> hb_sz;
615 /* Finish up a collection. Assumes lock is held, signals are disabled, */
616 /* but the world is otherwise running. */
617 void GC_finish_collection()
620 CLOCK_TYPE start_time;
621 CLOCK_TYPE finalize_time;
622 CLOCK_TYPE done_time;
624 GET_TIME(start_time);
625 finalize_time = start_time;
631 # if defined(LINUX) && defined(__ELF__) && !defined(SMALL_CONFIG)
632 if (getenv("GC_PRINT_ADDRESS_MAP") != 0) {
633 GC_print_address_map();
638 /* Mark all objects on the free list. All objects should be */
639 /* marked when we're done. */
641 register word size; /* current object size */
645 for (kind = 0; kind < GC_n_kinds; kind++) {
646 for (size = 1; size <= MAXOBJSZ; size++) {
647 q = GC_obj_kinds[kind].ok_freelist[size];
648 if (q != 0) GC_set_fl_marks(q);
652 GC_start_reclaim(TRUE);
653 /* The above just checks; it doesn't really reclaim anything. */
657 # ifdef STUBBORN_ALLOC
658 GC_clean_changing_list();
662 GET_TIME(finalize_time);
665 if (GC_print_back_height) {
666 # ifdef MAKE_BACK_GRAPH
667 GC_traverse_back_graph();
669 # ifndef SMALL_CONFIG
670 GC_err_printf0("Back height not available: "
671 "Rebuild collector with -DMAKE_BACK_GRAPH\n");
676 /* Clear free list mark bits, in case they got accidentally marked */
677 /* (or GC_find_leak is set and they were intentionally marked). */
678 /* Also subtract memory remaining from GC_mem_found count. */
679 /* Note that composite objects on free list are cleared. */
680 /* Thus accidentally marking a free list is not a problem; only */
681 /* objects on the list itself will be marked, and that's fixed here. */
683 register word size; /* current object size */
684 register ptr_t q; /* pointer to current object */
687 for (kind = 0; kind < GC_n_kinds; kind++) {
688 for (size = 1; size <= MAXOBJSZ; size++) {
689 q = GC_obj_kinds[kind].ok_freelist[size];
690 if (q != 0) GC_clear_fl_marks(q);
697 GC_printf1("Bytes recovered before sweep - f.l. count = %ld\n",
698 (long)WORDS_TO_BYTES(GC_mem_found));
700 /* Reconstruct free lists to contain everything not marked */
701 GC_start_reclaim(FALSE);
703 GC_used_heap_size_after_full = USED_HEAP_SIZE;
704 GC_need_full_gc = FALSE;
707 BYTES_TO_WORDS(USED_HEAP_SIZE - GC_used_heap_size_after_full)
708 > min_words_allocd();
713 "Immediately reclaimed %ld bytes in heap of size %lu bytes",
714 (long)WORDS_TO_BYTES(GC_mem_found),
715 (unsigned long)GC_heapsize);
717 GC_printf1("(%lu unmapped)", GC_unmapped_bytes);
720 "\n%lu (atomic) + %lu (composite) collectable bytes in use\n",
721 (unsigned long)WORDS_TO_BYTES(GC_atomic_in_use),
722 (unsigned long)WORDS_TO_BYTES(GC_composite_in_use));
726 GC_is_full_gc = FALSE;
727 /* Reset or increment counters for next cycle */
728 GC_words_allocd_before_gc += GC_words_allocd;
729 GC_non_gc_bytes_at_gc = GC_non_gc_bytes;
733 GC_finalizer_mem_freed = 0;
740 GC_printf2("Finalize + initiate sweep took %lu + %lu msecs\n",
741 MS_TIME_DIFF(finalize_time,start_time),
742 MS_TIME_DIFF(done_time,finalize_time));
746 /* Externally callable routine to invoke full, stop-world collection */
747 # if defined(__STDC__) || defined(__cplusplus)
748 int GC_try_to_collect(GC_stop_func stop_func)
750 int GC_try_to_collect(stop_func)
751 GC_stop_func stop_func;
757 if (GC_debugging_started) GC_print_all_smashed();
758 GC_INVOKE_FINALIZERS();
762 if (!GC_is_initialized) GC_init_inner();
763 /* Minimize junk left in my registers */
764 GC_noop(0,0,0,0,0,0);
765 result = (int)GC_try_to_collect_inner(stop_func);
770 if (GC_debugging_started) GC_print_all_smashed();
771 GC_INVOKE_FINALIZERS();
776 void GC_gcollect GC_PROTO(())
778 (void)GC_try_to_collect(GC_never_stop_func);
779 if (GC_have_errors) GC_print_all_errors();
782 word GC_n_heap_sects = 0; /* Number of sections currently in heap. */
785 * Use the chunk of memory starting at p of size bytes as part of the heap.
786 * Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE.
788 void GC_add_to_heap(p, bytes)
795 if (GC_n_heap_sects >= MAX_HEAP_SECTS) {
796 ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS");
798 phdr = GC_install_header(p);
800 /* This is extremely unlikely. Can't add it. This will */
801 /* almost certainly result in a 0 return from the allocator, */
802 /* which is entirely appropriate. */
805 GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p;
806 GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes;
808 words = BYTES_TO_WORDS(bytes);
809 phdr -> hb_sz = words;
810 phdr -> hb_map = (unsigned char *)1; /* A value != GC_invalid_map */
811 phdr -> hb_flags = 0;
813 GC_heapsize += bytes;
814 if ((ptr_t)p <= (ptr_t)GC_least_plausible_heap_addr
815 || GC_least_plausible_heap_addr == 0) {
816 GC_least_plausible_heap_addr = (GC_PTR)((ptr_t)p - sizeof(word));
817 /* Making it a little smaller than necessary prevents */
818 /* us from getting a false hit from the variable */
819 /* itself. There's some unintentional reflection */
822 if ((ptr_t)p + bytes >= (ptr_t)GC_greatest_plausible_heap_addr) {
823 GC_greatest_plausible_heap_addr = (GC_PTR)((ptr_t)p + bytes);
827 # if !defined(NO_DEBUGGING)
828 void GC_print_heap_sects()
832 GC_printf1("Total heap size: %lu\n", (unsigned long) GC_heapsize);
833 for (i = 0; i < GC_n_heap_sects; i++) {
834 unsigned long start = (unsigned long) GC_heap_sects[i].hs_start;
835 unsigned long len = (unsigned long) GC_heap_sects[i].hs_bytes;
839 GC_printf3("Section %ld from 0x%lx to 0x%lx ", (unsigned long)i,
840 start, (unsigned long)(start + len));
841 for (h = (struct hblk *)start; h < (struct hblk *)(start + len); h++) {
842 if (GC_is_black_listed(h, HBLKSIZE)) nbl++;
844 GC_printf2("%lu/%lu blacklisted\n", (unsigned long)nbl,
845 (unsigned long)(len/HBLKSIZE));
850 GC_PTR GC_least_plausible_heap_addr = (GC_PTR)ONES;
851 GC_PTR GC_greatest_plausible_heap_addr = 0;
856 return(x > y? x : y);
862 return(x < y? x : y);
865 # if defined(__STDC__) || defined(__cplusplus)
866 void GC_set_max_heap_size(GC_word n)
868 void GC_set_max_heap_size(n)
875 GC_word GC_max_retries = 0;
878 * this explicitly increases the size of the heap. It is used
879 * internally, but may also be invoked from GC_expand_hp by the user.
880 * The argument is in units of HBLKSIZE.
881 * Tiny values of n are rounded up.
882 * Returns FALSE on failure.
884 GC_bool GC_expand_hp_inner(n)
889 word expansion_slop; /* Number of bytes by which we expect the */
890 /* heap to expand soon. */
892 if (n < MINHINCR) n = MINHINCR;
893 bytes = n * HBLKSIZE;
894 /* Make sure bytes is a multiple of GC_page_size */
896 word mask = GC_page_size - 1;
901 if (GC_max_heapsize != 0 && GC_heapsize + bytes > GC_max_heapsize) {
902 /* Exceeded self-imposed limit */
905 space = GET_MEM(bytes);
908 if (GC_print_stats) {
909 GC_printf1("Failed to expand heap by %ld bytes\n",
910 (unsigned long)bytes);
916 if (GC_print_stats) {
917 GC_printf2("Increasing heap size by %lu after %lu allocated bytes\n",
918 (unsigned long)bytes,
919 (unsigned long)WORDS_TO_BYTES(GC_words_allocd));
921 GC_printf1("Root size = %lu\n", GC_root_size);
922 GC_print_block_list(); GC_print_hblkfreelist();
927 expansion_slop = 8 * WORDS_TO_BYTES(min_words_allocd());
928 if (5 * HBLKSIZE * MAXHINCR > expansion_slop) {
929 expansion_slop = 5 * HBLKSIZE * MAXHINCR;
931 if (GC_last_heap_addr == 0 && !((word)space & SIGNB)
932 || GC_last_heap_addr != 0 && GC_last_heap_addr < (ptr_t)space) {
933 /* Assume the heap is growing up */
934 GC_greatest_plausible_heap_addr =
935 GC_max(GC_greatest_plausible_heap_addr,
936 (ptr_t)space + bytes + expansion_slop);
938 /* Heap is growing down */
939 GC_least_plausible_heap_addr =
940 GC_min(GC_least_plausible_heap_addr,
941 (ptr_t)space - expansion_slop);
943 GC_prev_heap_addr = GC_last_heap_addr;
944 GC_last_heap_addr = (ptr_t)space;
945 GC_add_to_heap(space, bytes);
949 /* Really returns a bool, but it's externally visible, so that's clumsy. */
950 /* Arguments is in bytes. */
951 # if defined(__STDC__) || defined(__cplusplus)
952 int GC_expand_hp(size_t bytes)
954 int GC_expand_hp(bytes)
963 if (!GC_is_initialized) GC_init_inner();
964 result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes));
965 if (result) GC_requested_heapsize += bytes;
971 unsigned GC_fail_count = 0;
972 /* How many consecutive GC/expansion failures? */
973 /* Reset by GC_allochblk. */
975 GC_bool GC_collect_or_expand(needed_blocks, ignore_off_page)
977 GC_bool ignore_off_page;
979 if (!GC_incremental && !GC_dont_gc &&
980 (GC_dont_expand && GC_words_allocd > 0 || GC_should_collect())) {
983 word blocks_to_get = GC_heapsize/(HBLKSIZE*GC_free_space_divisor)
986 if (blocks_to_get > MAXHINCR) {
989 if (ignore_off_page) {
992 slop = 2*divHBLKSZ(BL_LIMIT);
993 if (slop > needed_blocks) slop = needed_blocks;
995 if (needed_blocks + slop > MAXHINCR) {
996 blocks_to_get = needed_blocks + slop;
998 blocks_to_get = MAXHINCR;
1001 if (!GC_expand_hp_inner(blocks_to_get)
1002 && !GC_expand_hp_inner(needed_blocks)) {
1003 if (GC_fail_count++ < GC_max_retries) {
1004 WARN("Out of Memory! Trying to continue ...\n", 0);
1005 GC_gcollect_inner();
1007 # if !defined(AMIGA) || !defined(GC_AMIGA_FASTALLOC)
1008 WARN("Out of Memory! Returning NIL!\n", 0);
1014 if (GC_fail_count && GC_print_stats) {
1015 GC_printf0("Memory available again ...\n");
1024 * Make sure the object free list for sz is not empty.
1025 * Return a pointer to the first object on the free list.
1026 * The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER.
1027 * Assumes we hold the allocator lock and signals are disabled.
1030 ptr_t GC_allocobj(sz, kind)
1034 ptr_t * flh = &(GC_obj_kinds[kind].ok_freelist[sz]);
1035 GC_bool tried_minor = FALSE;
1037 if (sz == 0) return(0);
1041 /* Do our share of marking work */
1042 if(TRUE_INCREMENTAL) GC_collect_a_little_inner(1);
1043 /* Sweep blocks for objects of this size */
1044 GC_continue_reclaim(sz, kind);
1047 GC_new_hblk(sz, kind);
1051 if (GC_incremental && GC_time_limit == GC_TIME_UNLIMITED
1052 && ! tried_minor ) {
1053 GC_collect_a_little_inner(1);
1056 if (!GC_collect_or_expand((word)1,FALSE)) {
1064 /* Successful allocation; reset failure count. */