1 /*
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) 1999-2004 Hewlett-Packard Development Company, L.P.
6 * Copyright (c) 2008-2019 Ivan Maidanski
7 *
8 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
9 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
10 *
11 * Permission is hereby granted to use or copy this program
12 * for any purpose, provided the above notices are retained on all copies.
13 * Permission to modify the code and to distribute modified code is granted,
14 * provided the above notices are retained, and a notice that the code was
15 * modified is included with the above copyright notice.
16 *
17 */
18
19 #include "private/gc_priv.h"
20
21 #include <stdio.h>
22 #if !defined(MACOS) && !defined(MSWINCE)
23 # include <signal.h>
24 # if !defined(SN_TARGET_ORBIS) && !defined(SN_TARGET_PSP2) \
25 && !defined(__CC_ARM)
26 # include <sys/types.h>
27 # endif
28 #endif
29
30 /*
31 * Separate free lists are maintained for different sized objects
32 * up to MAXOBJBYTES.
33 * The call GC_allocobj(i,k) ensures that the freelist for
34 * kind k objects of size i points to a non-empty
35 * free list. It returns a pointer to the first entry on the free list.
36 * In a single-threaded world, GC_allocobj may be called to allocate
37 * an object of small size lb (and NORMAL kind) as follows
38 * (GC_generic_malloc_inner is a wrapper over GC_allocobj which also
39 * fills in GC_size_map if needed):
40 *
41 * lg = GC_size_map[lb];
42 * op = GC_objfreelist[lg];
43 * if (NULL == op) {
44 * op = GC_generic_malloc_inner(lb, NORMAL);
45 * } else {
46 * GC_objfreelist[lg] = obj_link(op);
47 * GC_bytes_allocd += GRANULES_TO_BYTES((word)lg);
48 * }
49 *
50 * Note that this is very fast if the free list is non-empty; it should
51 * only involve the execution of 4 or 5 simple instructions.
52 * All composite objects on freelists are cleared, except for
53 * their first word.
54 */
55
56 /*
57 * The allocator uses GC_allochblk to allocate large chunks of objects.
58 * These chunks all start on addresses which are multiples of
59 * HBLKSZ. Each allocated chunk has an associated header,
60 * which can be located quickly based on the address of the chunk.
61 * (See headers.c for details.)
62 * This makes it possible to check quickly whether an
63 * arbitrary address corresponds to an object administered by the
64 * allocator.
65 */
66
67 word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */
68
69 word GC_gc_no = 0;
70
71 #ifndef NO_CLOCK
72 static unsigned long full_gc_total_time = 0; /* in msecs, may wrap */
73 static GC_bool measure_performance = FALSE;
74 /* Do performance measurements if set to true (e.g., */
75 /* accumulation of the total time of full collections). */
76
GC_start_performance_measurement(void)77 GC_API void GC_CALL GC_start_performance_measurement(void)
78 {
79 measure_performance = TRUE;
80 }
81
GC_get_full_gc_total_time(void)82 GC_API unsigned long GC_CALL GC_get_full_gc_total_time(void)
83 {
84 return full_gc_total_time;
85 }
86 #endif /* !NO_CLOCK */
87
88 #ifndef GC_DISABLE_INCREMENTAL
89 GC_INNER GC_bool GC_incremental = FALSE; /* By default, stop the world. */
90 #endif
91
GC_is_incremental_mode(void)92 GC_API int GC_CALL GC_is_incremental_mode(void)
93 {
94 return (int)GC_incremental;
95 }
96
97 #ifdef THREADS
98 int GC_parallel = FALSE; /* By default, parallel GC is off. */
99 #endif
100
101 #if defined(GC_FULL_FREQ) && !defined(CPPCHECK)
102 int GC_full_freq = GC_FULL_FREQ;
103 #else
104 int GC_full_freq = 19; /* Every 20th collection is a full */
105 /* collection, whether we need it */
106 /* or not. */
107 #endif
108
109 STATIC GC_bool GC_need_full_gc = FALSE;
110 /* Need full GC do to heap growth. */
111
112 #ifdef THREAD_LOCAL_ALLOC
113 GC_INNER GC_bool GC_world_stopped = FALSE;
114 #endif
115
116 STATIC word GC_used_heap_size_after_full = 0;
117
118 /* GC_copyright symbol is externally visible. */
119 EXTERN_C_BEGIN
120 extern const char * const GC_copyright[];
121 EXTERN_C_END
122 const char * const GC_copyright[] =
123 {"Copyright 1988, 1989 Hans-J. Boehm and Alan J. Demers ",
124 "Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",
125 "Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",
126 "Copyright (c) 1999-2009 by Hewlett-Packard Company. All rights reserved. ",
127 "Copyright (c) 2008-2019 Ivan Maidanski ",
128 "THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",
129 " EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",
130 "See source code for details." };
131
132 /* Version macros are now defined in gc_version.h, which is included by */
133 /* gc.h, which is included by gc_priv.h. */
134 #ifndef GC_NO_VERSION_VAR
135 EXTERN_C_BEGIN
136 extern const unsigned GC_version;
137 EXTERN_C_END
138 const unsigned GC_version = ((GC_VERSION_MAJOR << 16) |
139 (GC_VERSION_MINOR << 8) | GC_VERSION_MICRO);
140 #endif
141
GC_get_version(void)142 GC_API unsigned GC_CALL GC_get_version(void)
143 {
144 return (GC_VERSION_MAJOR << 16) | (GC_VERSION_MINOR << 8) |
145 GC_VERSION_MICRO;
146 }
147
148 /* some more variables */
149
150 #ifdef GC_DONT_EXPAND
151 int GC_dont_expand = TRUE;
152 #else
153 int GC_dont_expand = FALSE;
154 #endif
155
156 #if defined(GC_FREE_SPACE_DIVISOR) && !defined(CPPCHECK)
157 word GC_free_space_divisor = GC_FREE_SPACE_DIVISOR; /* must be > 0 */
158 #else
159 word GC_free_space_divisor = 3;
160 #endif
161
GC_never_stop_func(void)162 GC_INNER int GC_CALLBACK GC_never_stop_func(void)
163 {
164 return(0);
165 }
166
167 #if defined(GC_TIME_LIMIT) && !defined(CPPCHECK)
168 unsigned long GC_time_limit = GC_TIME_LIMIT;
169 /* We try to keep pause times from exceeding */
170 /* this by much. In milliseconds. */
171 #else
172 unsigned long GC_time_limit = 50;
173 #endif
174
175 #ifndef NO_CLOCK
176 STATIC CLOCK_TYPE GC_start_time = CLOCK_TYPE_INITIALIZER;
177 /* Time at which we stopped world. */
178 /* used only in GC_timeout_stop_func. */
179 #endif
180
181 STATIC int GC_n_attempts = 0; /* Number of attempts at finishing */
182 /* collection within GC_time_limit. */
183
184 STATIC GC_stop_func GC_default_stop_func = GC_never_stop_func;
185 /* accessed holding the lock. */
186
GC_set_stop_func(GC_stop_func stop_func)187 GC_API void GC_CALL GC_set_stop_func(GC_stop_func stop_func)
188 {
189 DCL_LOCK_STATE;
190 GC_ASSERT(NONNULL_ARG_NOT_NULL(stop_func));
191 LOCK();
192 GC_default_stop_func = stop_func;
193 UNLOCK();
194 }
195
GC_get_stop_func(void)196 GC_API GC_stop_func GC_CALL GC_get_stop_func(void)
197 {
198 GC_stop_func stop_func;
199 DCL_LOCK_STATE;
200 LOCK();
201 stop_func = GC_default_stop_func;
202 UNLOCK();
203 return stop_func;
204 }
205
206 #if defined(GC_DISABLE_INCREMENTAL) || defined(NO_CLOCK)
207 # define GC_timeout_stop_func GC_default_stop_func
208 #else
GC_timeout_stop_func(void)209 STATIC int GC_CALLBACK GC_timeout_stop_func (void)
210 {
211 CLOCK_TYPE current_time;
212 static unsigned count = 0;
213 unsigned long time_diff;
214
215 if ((*GC_default_stop_func)())
216 return(1);
217
218 if ((count++ & 3) != 0) return(0);
219 GET_TIME(current_time);
220 time_diff = MS_TIME_DIFF(current_time,GC_start_time);
221 if (time_diff >= GC_time_limit) {
222 GC_COND_LOG_PRINTF(
223 "Abandoning stopped marking after %lu msecs (attempt %d)\n",
224 time_diff, GC_n_attempts);
225 return(1);
226 }
227 return(0);
228 }
229 #endif /* !GC_DISABLE_INCREMENTAL */
230
231 #ifdef THREADS
232 GC_INNER word GC_total_stacksize = 0; /* updated on every push_all_stacks */
233 #endif
234
235 static size_t min_bytes_allocd_minimum = 1;
236 /* The lowest value returned by min_bytes_allocd(). */
237
GC_set_min_bytes_allocd(size_t value)238 GC_API void GC_CALL GC_set_min_bytes_allocd(size_t value)
239 {
240 GC_ASSERT(value > 0);
241 min_bytes_allocd_minimum = value;
242 }
243
GC_get_min_bytes_allocd(void)244 GC_API size_t GC_CALL GC_get_min_bytes_allocd(void)
245 {
246 return min_bytes_allocd_minimum;
247 }
248
249 /* Return the minimum number of bytes that must be allocated between */
250 /* collections to amortize the collection cost. Should be non-zero. */
min_bytes_allocd(void)251 static word min_bytes_allocd(void)
252 {
253 word result;
254 word stack_size;
255 word total_root_size; /* includes double stack size, */
256 /* since the stack is expensive */
257 /* to scan. */
258 word scan_size; /* Estimate of memory to be scanned */
259 /* during normal GC. */
260
261 # ifdef THREADS
262 if (GC_need_to_lock) {
263 /* We are multi-threaded... */
264 stack_size = GC_total_stacksize;
265 /* For now, we just use the value computed during the latest GC. */
266 # ifdef DEBUG_THREADS
267 GC_log_printf("Total stacks size: %lu\n",
268 (unsigned long)stack_size);
269 # endif
270 } else
271 # endif
272 /* else*/ {
273 # ifdef STACK_NOT_SCANNED
274 stack_size = 0;
275 # elif defined(STACK_GROWS_UP)
276 stack_size = GC_approx_sp() - GC_stackbottom;
277 # else
278 stack_size = GC_stackbottom - GC_approx_sp();
279 # endif
280 }
281
282 total_root_size = 2 * stack_size + GC_root_size;
283 scan_size = 2 * GC_composite_in_use + GC_atomic_in_use / 4
284 + total_root_size;
285 result = scan_size / GC_free_space_divisor;
286 if (GC_incremental) {
287 result /= 2;
288 }
289 return result > min_bytes_allocd_minimum
290 ? result : min_bytes_allocd_minimum;
291 }
292
293 STATIC word GC_non_gc_bytes_at_gc = 0;
294 /* Number of explicitly managed bytes of storage */
295 /* at last collection. */
296
297 /* Return the number of bytes allocated, adjusted for explicit storage */
298 /* management, etc.. This number is used in deciding when to trigger */
299 /* collections. */
GC_adj_bytes_allocd(void)300 STATIC word GC_adj_bytes_allocd(void)
301 {
302 signed_word result;
303 signed_word expl_managed = (signed_word)GC_non_gc_bytes
304 - (signed_word)GC_non_gc_bytes_at_gc;
305
306 /* Don't count what was explicitly freed, or newly allocated for */
307 /* explicit management. Note that deallocating an explicitly */
308 /* managed object should not alter result, assuming the client */
309 /* is playing by the rules. */
310 result = (signed_word)GC_bytes_allocd
311 + (signed_word)GC_bytes_dropped
312 - (signed_word)GC_bytes_freed
313 + (signed_word)GC_finalizer_bytes_freed
314 - expl_managed;
315 if (result > (signed_word)GC_bytes_allocd) {
316 result = GC_bytes_allocd;
317 /* probably client bug or unfortunate scheduling */
318 }
319 result += GC_bytes_finalized;
320 /* We count objects enqueued for finalization as though they */
321 /* had been reallocated this round. Finalization is user */
322 /* visible progress. And if we don't count this, we have */
323 /* stability problems for programs that finalize all objects. */
324 if (result < (signed_word)(GC_bytes_allocd >> 3)) {
325 /* Always count at least 1/8 of the allocations. We don't want */
326 /* to collect too infrequently, since that would inhibit */
327 /* coalescing of free storage blocks. */
328 /* This also makes us partially robust against client bugs. */
329 return(GC_bytes_allocd >> 3);
330 } else {
331 return(result);
332 }
333 }
334
335
336 /* Clear up a few frames worth of garbage left at the top of the stack. */
337 /* This is used to prevent us from accidentally treating garbage left */
338 /* on the stack by other parts of the collector as roots. This */
339 /* differs from the code in misc.c, which actually tries to keep the */
340 /* stack clear of long-lived, client-generated garbage. */
GC_clear_a_few_frames(void)341 STATIC void GC_clear_a_few_frames(void)
342 {
343 # ifndef CLEAR_NWORDS
344 # define CLEAR_NWORDS 64
345 # endif
346 volatile word frames[CLEAR_NWORDS];
347 BZERO((word *)frames, CLEAR_NWORDS * sizeof(word));
348 }
349
350 /* Heap size at which we need a collection to avoid expanding past */
351 /* limits used by blacklisting. */
352 STATIC word GC_collect_at_heapsize = GC_WORD_MAX;
353
354 /* Have we allocated enough to amortize a collection? */
GC_should_collect(void)355 GC_INNER GC_bool GC_should_collect(void)
356 {
357 static word last_min_bytes_allocd;
358 static word last_gc_no;
359 if (last_gc_no != GC_gc_no) {
360 last_gc_no = GC_gc_no;
361 last_min_bytes_allocd = min_bytes_allocd();
362 }
363 return(GC_adj_bytes_allocd() >= last_min_bytes_allocd
364 || GC_heapsize >= GC_collect_at_heapsize);
365 }
366
367 /* STATIC */ GC_start_callback_proc GC_start_call_back = 0;
368 /* Called at start of full collections. */
369 /* Not called if 0. Called with the allocation */
370 /* lock held. Not used by GC itself. */
371
GC_set_start_callback(GC_start_callback_proc fn)372 GC_API void GC_CALL GC_set_start_callback(GC_start_callback_proc fn)
373 {
374 DCL_LOCK_STATE;
375 LOCK();
376 GC_start_call_back = fn;
377 UNLOCK();
378 }
379
GC_get_start_callback(void)380 GC_API GC_start_callback_proc GC_CALL GC_get_start_callback(void)
381 {
382 GC_start_callback_proc fn;
383 DCL_LOCK_STATE;
384 LOCK();
385 fn = GC_start_call_back;
386 UNLOCK();
387 return fn;
388 }
389
GC_notify_full_gc(void)390 GC_INLINE void GC_notify_full_gc(void)
391 {
392 if (GC_start_call_back != 0) {
393 (*GC_start_call_back)();
394 }
395 }
396
397 STATIC GC_bool GC_is_full_gc = FALSE;
398
399 STATIC GC_bool GC_stopped_mark(GC_stop_func stop_func);
400 STATIC void GC_finish_collection(void);
401
402 /*
403 * Initiate a garbage collection if appropriate.
404 * Choose judiciously
405 * between partial, full, and stop-world collections.
406 */
GC_maybe_gc(void)407 STATIC void GC_maybe_gc(void)
408 {
409 GC_ASSERT(I_HOLD_LOCK());
410 ASSERT_CANCEL_DISABLED();
411 if (GC_should_collect()) {
412 static int n_partial_gcs = 0;
413
414 if (!GC_incremental) {
415 /* TODO: If possible, GC_default_stop_func should be used here */
416 GC_try_to_collect_inner(GC_never_stop_func);
417 n_partial_gcs = 0;
418 return;
419 } else {
420 # ifdef PARALLEL_MARK
421 if (GC_parallel)
422 GC_wait_for_reclaim();
423 # endif
424 if (GC_need_full_gc || n_partial_gcs >= GC_full_freq) {
425 GC_COND_LOG_PRINTF(
426 "***>Full mark for collection #%lu after %lu allocd bytes\n",
427 (unsigned long)GC_gc_no + 1, (unsigned long)GC_bytes_allocd);
428 GC_promote_black_lists();
429 (void)GC_reclaim_all((GC_stop_func)0, TRUE);
430 GC_notify_full_gc();
431 GC_clear_marks();
432 n_partial_gcs = 0;
433 GC_is_full_gc = TRUE;
434 } else {
435 n_partial_gcs++;
436 }
437 }
438 /* We try to mark with the world stopped. */
439 /* If we run out of time, this turns into */
440 /* incremental marking. */
441 # ifndef NO_CLOCK
442 if (GC_time_limit != GC_TIME_UNLIMITED) { GET_TIME(GC_start_time); }
443 # endif
444 /* TODO: If possible, GC_default_stop_func should be */
445 /* used instead of GC_never_stop_func here. */
446 if (GC_stopped_mark(GC_time_limit == GC_TIME_UNLIMITED?
447 GC_never_stop_func : GC_timeout_stop_func)) {
448 # ifdef SAVE_CALL_CHAIN
449 GC_save_callers(GC_last_stack);
450 # endif
451 GC_finish_collection();
452 } else {
453 if (!GC_is_full_gc) {
454 /* Count this as the first attempt */
455 GC_n_attempts++;
456 }
457 }
458 }
459 }
460
461 STATIC GC_on_collection_event_proc GC_on_collection_event = 0;
462
GC_set_on_collection_event(GC_on_collection_event_proc fn)463 GC_API void GC_CALL GC_set_on_collection_event(GC_on_collection_event_proc fn)
464 {
465 /* fn may be 0 (means no event notifier). */
466 DCL_LOCK_STATE;
467 LOCK();
468 GC_on_collection_event = fn;
469 UNLOCK();
470 }
471
GC_get_on_collection_event(void)472 GC_API GC_on_collection_event_proc GC_CALL GC_get_on_collection_event(void)
473 {
474 GC_on_collection_event_proc fn;
475 DCL_LOCK_STATE;
476 LOCK();
477 fn = GC_on_collection_event;
478 UNLOCK();
479 return fn;
480 }
481
482 /* Stop the world garbage collection. If stop_func is not */
483 /* GC_never_stop_func then abort if stop_func returns TRUE. */
484 /* Return TRUE if we successfully completed the collection. */
GC_try_to_collect_inner(GC_stop_func stop_func)485 GC_INNER GC_bool GC_try_to_collect_inner(GC_stop_func stop_func)
486 {
487 # ifndef NO_CLOCK
488 CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
489 GC_bool start_time_valid;
490 # endif
491
492 ASSERT_CANCEL_DISABLED();
493 GC_ASSERT(I_HOLD_LOCK());
494 if (GC_dont_gc || (*stop_func)()) return FALSE;
495 if (GC_on_collection_event)
496 GC_on_collection_event(GC_EVENT_START);
497 if (GC_incremental && GC_collection_in_progress()) {
498 GC_COND_LOG_PRINTF(
499 "GC_try_to_collect_inner: finishing collection in progress\n");
500 /* Just finish collection already in progress. */
501 while(GC_collection_in_progress()) {
502 if ((*stop_func)()) {
503 /* TODO: Notify GC_EVENT_ABANDON */
504 return(FALSE);
505 }
506 GC_collect_a_little_inner(1);
507 }
508 }
509 GC_notify_full_gc();
510 # ifndef NO_CLOCK
511 start_time_valid = FALSE;
512 if ((GC_print_stats | (int)measure_performance) != 0) {
513 if (GC_print_stats)
514 GC_log_printf("Initiating full world-stop collection!\n");
515 start_time_valid = TRUE;
516 GET_TIME(start_time);
517 }
518 # endif
519 GC_promote_black_lists();
520 /* Make sure all blocks have been reclaimed, so sweep routines */
521 /* don't see cleared mark bits. */
522 /* If we're guaranteed to finish, then this is unnecessary. */
523 /* In the find_leak case, we have to finish to guarantee that */
524 /* previously unmarked objects are not reported as leaks. */
525 # ifdef PARALLEL_MARK
526 if (GC_parallel)
527 GC_wait_for_reclaim();
528 # endif
529 if ((GC_find_leak || stop_func != GC_never_stop_func)
530 && !GC_reclaim_all(stop_func, FALSE)) {
531 /* Aborted. So far everything is still consistent. */
532 /* TODO: Notify GC_EVENT_ABANDON */
533 return(FALSE);
534 }
535 GC_invalidate_mark_state(); /* Flush mark stack. */
536 GC_clear_marks();
537 # ifdef SAVE_CALL_CHAIN
538 GC_save_callers(GC_last_stack);
539 # endif
540 GC_is_full_gc = TRUE;
541 if (!GC_stopped_mark(stop_func)) {
542 if (!GC_incremental) {
543 /* We're partially done and have no way to complete or use */
544 /* current work. Reestablish invariants as cheaply as */
545 /* possible. */
546 GC_invalidate_mark_state();
547 GC_unpromote_black_lists();
548 } /* else we claim the world is already still consistent. We'll */
549 /* finish incrementally. */
550 /* TODO: Notify GC_EVENT_ABANDON */
551 return(FALSE);
552 }
553 GC_finish_collection();
554 # ifndef NO_CLOCK
555 if (start_time_valid) {
556 CLOCK_TYPE current_time;
557 unsigned long time_diff;
558
559 GET_TIME(current_time);
560 time_diff = MS_TIME_DIFF(current_time, start_time);
561 if (measure_performance)
562 full_gc_total_time += time_diff; /* may wrap */
563 if (GC_print_stats)
564 GC_log_printf("Complete collection took %lu msecs\n", time_diff);
565 }
566 # endif
567 if (GC_on_collection_event)
568 GC_on_collection_event(GC_EVENT_END);
569 return(TRUE);
570 }
571
572 /*
573 * Perform n units of garbage collection work. A unit is intended to touch
574 * roughly GC_rate pages. Every once in a while, we do more than that.
575 * This needs to be a fairly large number with our current incremental
576 * GC strategy, since otherwise we allocate too much during GC, and the
577 * cleanup gets expensive.
578 */
579 #ifndef GC_RATE
580 # define GC_RATE 10
581 #endif
582
583 #ifndef MAX_PRIOR_ATTEMPTS
584 # define MAX_PRIOR_ATTEMPTS 1
585 #endif
586 /* Maximum number of prior attempts at world stop marking */
587 /* A value of 1 means that we finish the second time, no matter */
588 /* how long it takes. Doesn't count the initial root scan */
589 /* for a full GC. */
590
591 STATIC int GC_deficit = 0;/* The number of extra calls to GC_mark_some */
592 /* that we have made. */
593
594 STATIC int GC_rate = GC_RATE;
595
GC_set_rate(int value)596 GC_API void GC_CALL GC_set_rate(int value)
597 {
598 GC_ASSERT(value > 0);
599 GC_rate = value;
600 }
601
GC_get_rate(void)602 GC_API int GC_CALL GC_get_rate(void)
603 {
604 return GC_rate;
605 }
606
607 static int max_prior_attempts = MAX_PRIOR_ATTEMPTS;
608
GC_set_max_prior_attempts(int value)609 GC_API void GC_CALL GC_set_max_prior_attempts(int value)
610 {
611 GC_ASSERT(value >= 0);
612 max_prior_attempts = value;
613 }
614
GC_get_max_prior_attempts(void)615 GC_API int GC_CALL GC_get_max_prior_attempts(void)
616 {
617 return max_prior_attempts;
618 }
619
GC_collect_a_little_inner(int n)620 GC_INNER void GC_collect_a_little_inner(int n)
621 {
622 IF_CANCEL(int cancel_state;)
623
624 GC_ASSERT(I_HOLD_LOCK());
625 if (GC_dont_gc) return;
626
627 DISABLE_CANCEL(cancel_state);
628 if (GC_incremental && GC_collection_in_progress()) {
629 int i;
630 int max_deficit = GC_rate * n;
631
632 for (i = GC_deficit; i < max_deficit; i++) {
633 if (GC_mark_some((ptr_t)0)) {
634 /* Need to finish a collection */
635 # ifdef SAVE_CALL_CHAIN
636 GC_save_callers(GC_last_stack);
637 # endif
638 # ifdef PARALLEL_MARK
639 if (GC_parallel)
640 GC_wait_for_reclaim();
641 # endif
642 if (GC_n_attempts < max_prior_attempts
643 && GC_time_limit != GC_TIME_UNLIMITED) {
644 # ifndef NO_CLOCK
645 GET_TIME(GC_start_time);
646 # endif
647 if (!GC_stopped_mark(GC_timeout_stop_func)) {
648 GC_n_attempts++;
649 break;
650 }
651 } else {
652 /* TODO: If possible, GC_default_stop_func should be */
653 /* used here. */
654 (void)GC_stopped_mark(GC_never_stop_func);
655 }
656 GC_finish_collection();
657 break;
658 }
659 }
660 if (GC_deficit > 0) {
661 GC_deficit -= max_deficit;
662 if (GC_deficit < 0)
663 GC_deficit = 0;
664 }
665 } else {
666 GC_maybe_gc();
667 }
668 RESTORE_CANCEL(cancel_state);
669 }
670
671 GC_INNER void (*GC_check_heap)(void) = 0;
672 GC_INNER void (*GC_print_all_smashed)(void) = 0;
673
GC_collect_a_little(void)674 GC_API int GC_CALL GC_collect_a_little(void)
675 {
676 int result;
677 DCL_LOCK_STATE;
678
679 LOCK();
680 GC_collect_a_little_inner(1);
681 result = (int)GC_collection_in_progress();
682 UNLOCK();
683 if (!result && GC_debugging_started) GC_print_all_smashed();
684 return(result);
685 }
686
687 #ifndef NO_CLOCK
688 /* Variables for world-stop average delay time statistic computation. */
689 /* "divisor" is incremented every world-stop and halved when reached */
690 /* its maximum (or upon "total_time" overflow). */
691 static unsigned world_stopped_total_time = 0;
692 static unsigned world_stopped_total_divisor = 0;
693 # ifndef MAX_TOTAL_TIME_DIVISOR
694 /* We shall not use big values here (so "outdated" delay time */
695 /* values would have less impact on "average" delay time value than */
696 /* newer ones). */
697 # define MAX_TOTAL_TIME_DIVISOR 1000
698 # endif
699 #endif /* !NO_CLOCK */
700
701 #ifdef USE_MUNMAP
702 # define IF_USE_MUNMAP(x) x
703 # define COMMA_IF_USE_MUNMAP(x) /* comma */, x
704 #else
705 # define IF_USE_MUNMAP(x) /* empty */
706 # define COMMA_IF_USE_MUNMAP(x) /* empty */
707 #endif
708
709 /*
710 * We stop the world and mark from all roots.
711 * If stop_func() ever returns TRUE, we may fail and return FALSE.
712 * Increment GC_gc_no if we succeed.
713 */
GC_stopped_mark(GC_stop_func stop_func)714 STATIC GC_bool GC_stopped_mark(GC_stop_func stop_func)
715 {
716 unsigned i;
717 # ifndef NO_CLOCK
718 CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
719 # endif
720
721 GC_ASSERT(I_HOLD_LOCK());
722 # if !defined(REDIRECT_MALLOC) && defined(USE_WINALLOC)
723 GC_add_current_malloc_heap();
724 # endif
725 # if defined(REGISTER_LIBRARIES_EARLY)
726 GC_cond_register_dynamic_libraries();
727 # endif
728
729 # ifndef NO_CLOCK
730 if (GC_PRINT_STATS_FLAG)
731 GET_TIME(start_time);
732 # endif
733
734 # if !defined(GC_NO_FINALIZATION) && !defined(GC_TOGGLE_REFS_NOT_NEEDED)
735 GC_process_togglerefs();
736 # endif
737 # ifdef THREADS
738 if (GC_on_collection_event)
739 GC_on_collection_event(GC_EVENT_PRE_STOP_WORLD);
740 # endif
741 STOP_WORLD();
742 # ifdef THREADS
743 if (GC_on_collection_event)
744 GC_on_collection_event(GC_EVENT_POST_STOP_WORLD);
745 # endif
746
747 # ifdef THREAD_LOCAL_ALLOC
748 GC_world_stopped = TRUE;
749 # endif
750 /* Output blank line for convenience here */
751 GC_COND_LOG_PRINTF(
752 "\n--> Marking for collection #%lu after %lu allocated bytes\n",
753 (unsigned long)GC_gc_no + 1, (unsigned long) GC_bytes_allocd);
754 # ifdef MAKE_BACK_GRAPH
755 if (GC_print_back_height) {
756 GC_build_back_graph();
757 }
758 # endif
759
760 /* Mark from all roots. */
761 if (GC_on_collection_event)
762 GC_on_collection_event(GC_EVENT_MARK_START);
763
764 /* Minimize junk left in my registers and on the stack */
765 GC_clear_a_few_frames();
766 GC_noop6(0,0,0,0,0,0);
767
768 GC_initiate_gc();
769 for (i = 0;;i++) {
770 if ((*stop_func)()) {
771 GC_COND_LOG_PRINTF("Abandoned stopped marking after"
772 " %u iterations\n", i);
773 GC_deficit = i; /* Give the mutator a chance. */
774 # ifdef THREAD_LOCAL_ALLOC
775 GC_world_stopped = FALSE;
776 # endif
777
778 # ifdef THREADS
779 if (GC_on_collection_event)
780 GC_on_collection_event(GC_EVENT_PRE_START_WORLD);
781 # endif
782
783 START_WORLD();
784
785 # ifdef THREADS
786 if (GC_on_collection_event)
787 GC_on_collection_event(GC_EVENT_POST_START_WORLD);
788 # endif
789
790 /* TODO: Notify GC_EVENT_MARK_ABANDON */
791 return(FALSE);
792 }
793 if (GC_mark_some(GC_approx_sp())) break;
794 }
795
796 GC_gc_no++;
797 GC_DBGLOG_PRINTF("GC #%lu freed %ld bytes, heap %lu KiB"
798 IF_USE_MUNMAP(" (+ %lu KiB unmapped)") "\n",
799 (unsigned long)GC_gc_no, (long)GC_bytes_found,
800 TO_KiB_UL(GC_heapsize - GC_unmapped_bytes) /*, */
801 COMMA_IF_USE_MUNMAP(TO_KiB_UL(GC_unmapped_bytes)));
802
803 /* Check all debugged objects for consistency */
804 if (GC_debugging_started) {
805 (*GC_check_heap)();
806 }
807 if (GC_on_collection_event)
808 GC_on_collection_event(GC_EVENT_MARK_END);
809
810 # ifdef THREAD_LOCAL_ALLOC
811 GC_world_stopped = FALSE;
812 # endif
813
814 # ifdef THREADS
815 if (GC_on_collection_event)
816 GC_on_collection_event(GC_EVENT_PRE_START_WORLD);
817 # endif
818
819 START_WORLD();
820
821 # ifdef THREADS
822 if (GC_on_collection_event)
823 GC_on_collection_event(GC_EVENT_POST_START_WORLD);
824 # endif
825
826 # ifndef NO_CLOCK
827 if (GC_PRINT_STATS_FLAG) {
828 unsigned long time_diff;
829 unsigned total_time, divisor;
830 CLOCK_TYPE current_time;
831
832 GET_TIME(current_time);
833 time_diff = MS_TIME_DIFF(current_time,start_time);
834
835 /* Compute new world-stop delay total time */
836 total_time = world_stopped_total_time;
837 divisor = world_stopped_total_divisor;
838 if ((int)total_time < 0 || divisor >= MAX_TOTAL_TIME_DIVISOR) {
839 /* Halve values if overflow occurs */
840 total_time >>= 1;
841 divisor >>= 1;
842 }
843 total_time += time_diff < (((unsigned)-1) >> 1) ?
844 (unsigned)time_diff : ((unsigned)-1) >> 1;
845 /* Update old world_stopped_total_time and its divisor */
846 world_stopped_total_time = total_time;
847 world_stopped_total_divisor = ++divisor;
848
849 GC_ASSERT(divisor != 0);
850 GC_log_printf(
851 "World-stopped marking took %lu msecs (%u in average)\n",
852 time_diff, total_time / divisor);
853 }
854 # endif
855 return(TRUE);
856 }
857
858 /* Set all mark bits for the free list whose first entry is q */
GC_set_fl_marks(ptr_t q)859 GC_INNER void GC_set_fl_marks(ptr_t q)
860 {
861 if (q != NULL) {
862 struct hblk *h = HBLKPTR(q);
863 struct hblk *last_h = h;
864 hdr *hhdr = HDR(h);
865 IF_PER_OBJ(word sz = hhdr->hb_sz;)
866
867 for (;;) {
868 word bit_no = MARK_BIT_NO((ptr_t)q - (ptr_t)h, sz);
869
870 if (!mark_bit_from_hdr(hhdr, bit_no)) {
871 set_mark_bit_from_hdr(hhdr, bit_no);
872 ++hhdr -> hb_n_marks;
873 }
874
875 q = (ptr_t)obj_link(q);
876 if (q == NULL)
877 break;
878
879 h = HBLKPTR(q);
880 if (h != last_h) {
881 last_h = h;
882 hhdr = HDR(h);
883 IF_PER_OBJ(sz = hhdr->hb_sz;)
884 }
885 }
886 }
887 }
888
889 #if defined(GC_ASSERTIONS) && defined(THREAD_LOCAL_ALLOC)
890 /* Check that all mark bits for the free list whose first entry is */
891 /* (*pfreelist) are set. Check skipped if points to a special value. */
GC_check_fl_marks(void ** pfreelist)892 void GC_check_fl_marks(void **pfreelist)
893 {
894 /* TODO: There is a data race with GC_FAST_MALLOC_GRANS (which does */
895 /* not do atomic updates to the free-list). The race seems to be */
896 /* harmless, and for now we just skip this check in case of TSan. */
897 # if defined(AO_HAVE_load_acquire_read) && !defined(THREAD_SANITIZER)
898 AO_t *list = (AO_t *)AO_load_acquire_read((AO_t *)pfreelist);
899 /* Atomic operations are used because the world is running. */
900 AO_t *prev;
901 AO_t *p;
902
903 if ((word)list <= HBLKSIZE) return;
904
905 prev = (AO_t *)pfreelist;
906 for (p = list; p != NULL;) {
907 AO_t *next;
908
909 if (!GC_is_marked(p)) {
910 ABORT_ARG2("Unmarked local free list entry",
911 ": object %p on list %p", (void *)p, (void *)list);
912 }
913
914 /* While traversing the free-list, it re-reads the pointer to */
915 /* the current node before accepting its next pointer and */
916 /* bails out if the latter has changed. That way, it won't */
917 /* try to follow the pointer which might be been modified */
918 /* after the object was returned to the client. It might */
919 /* perform the mark-check on the just allocated object but */
920 /* that should be harmless. */
921 next = (AO_t *)AO_load_acquire_read(p);
922 if (AO_load(prev) != (AO_t)p)
923 break;
924 prev = p;
925 p = next;
926 }
927 # else
928 /* FIXME: Not implemented (just skipped). */
929 (void)pfreelist;
930 # endif
931 }
932 #endif /* GC_ASSERTIONS && THREAD_LOCAL_ALLOC */
933
934 /* Clear all mark bits for the free list whose first entry is q */
935 /* Decrement GC_bytes_found by number of bytes on free list. */
GC_clear_fl_marks(ptr_t q)936 STATIC void GC_clear_fl_marks(ptr_t q)
937 {
938 struct hblk *h = HBLKPTR(q);
939 struct hblk *last_h = h;
940 hdr *hhdr = HDR(h);
941 word sz = hhdr->hb_sz; /* Normally set only once. */
942
943 for (;;) {
944 word bit_no = MARK_BIT_NO((ptr_t)q - (ptr_t)h, sz);
945
946 if (mark_bit_from_hdr(hhdr, bit_no)) {
947 size_t n_marks = hhdr -> hb_n_marks;
948
949 GC_ASSERT(n_marks != 0);
950 clear_mark_bit_from_hdr(hhdr, bit_no);
951 n_marks--;
952 # ifdef PARALLEL_MARK
953 /* Appr. count, don't decrement to zero! */
954 if (0 != n_marks || !GC_parallel) {
955 hhdr -> hb_n_marks = n_marks;
956 }
957 # else
958 hhdr -> hb_n_marks = n_marks;
959 # endif
960 }
961 GC_bytes_found -= sz;
962
963 q = (ptr_t)obj_link(q);
964 if (q == NULL)
965 break;
966
967 h = HBLKPTR(q);
968 if (h != last_h) {
969 last_h = h;
970 hhdr = HDR(h);
971 sz = hhdr->hb_sz;
972 }
973 }
974 }
975
976 #if defined(GC_ASSERTIONS) && defined(THREAD_LOCAL_ALLOC)
977 void GC_check_tls(void);
978 #endif
979
980 GC_on_heap_resize_proc GC_on_heap_resize = 0;
981
982 /* Used for logging only. */
GC_compute_heap_usage_percent(void)983 GC_INLINE int GC_compute_heap_usage_percent(void)
984 {
985 word used = GC_composite_in_use + GC_atomic_in_use;
986 word heap_sz = GC_heapsize - GC_unmapped_bytes;
987 return used >= heap_sz ? 0 : used < GC_WORD_MAX / 100 ?
988 (int)((used * 100) / heap_sz) : (int)(used / (heap_sz / 100));
989 }
990
991 /* Finish up a collection. Assumes mark bits are consistent, lock is */
992 /* held, but the world is otherwise running. */
GC_finish_collection(void)993 STATIC void GC_finish_collection(void)
994 {
995 # ifndef NO_CLOCK
996 CLOCK_TYPE start_time = CLOCK_TYPE_INITIALIZER;
997 CLOCK_TYPE finalize_time = CLOCK_TYPE_INITIALIZER;
998 # endif
999
1000 GC_ASSERT(I_HOLD_LOCK());
1001 # if defined(GC_ASSERTIONS) \
1002 && defined(THREAD_LOCAL_ALLOC) && !defined(DBG_HDRS_ALL)
1003 /* Check that we marked some of our own data. */
1004 /* TODO: Add more checks. */
1005 GC_check_tls();
1006 # endif
1007
1008 # ifndef NO_CLOCK
1009 if (GC_print_stats)
1010 GET_TIME(start_time);
1011 # endif
1012 if (GC_on_collection_event)
1013 GC_on_collection_event(GC_EVENT_RECLAIM_START);
1014
1015 # ifndef GC_GET_HEAP_USAGE_NOT_NEEDED
1016 if (GC_bytes_found > 0)
1017 GC_reclaimed_bytes_before_gc += (word)GC_bytes_found;
1018 # endif
1019 GC_bytes_found = 0;
1020 # if defined(LINUX) && defined(__ELF__) && !defined(SMALL_CONFIG)
1021 if (GETENV("GC_PRINT_ADDRESS_MAP") != 0) {
1022 GC_print_address_map();
1023 }
1024 # endif
1025 COND_DUMP;
1026 if (GC_find_leak) {
1027 /* Mark all objects on the free list. All objects should be */
1028 /* marked when we're done. */
1029 word size; /* current object size */
1030 unsigned kind;
1031 ptr_t q;
1032
1033 for (kind = 0; kind < GC_n_kinds; kind++) {
1034 for (size = 1; size <= MAXOBJGRANULES; size++) {
1035 q = (ptr_t)GC_obj_kinds[kind].ok_freelist[size];
1036 if (q != NULL)
1037 GC_set_fl_marks(q);
1038 }
1039 }
1040 GC_start_reclaim(TRUE);
1041 /* The above just checks; it doesn't really reclaim anything. */
1042 }
1043
1044 # ifndef GC_NO_FINALIZATION
1045 GC_finalize();
1046 # endif
1047 # ifndef NO_CLOCK
1048 if (GC_print_stats)
1049 GET_TIME(finalize_time);
1050 # endif
1051
1052 if (GC_print_back_height) {
1053 # ifdef MAKE_BACK_GRAPH
1054 GC_traverse_back_graph();
1055 # elif !defined(SMALL_CONFIG)
1056 GC_err_printf("Back height not available: "
1057 "Rebuild collector with -DMAKE_BACK_GRAPH\n");
1058 # endif
1059 }
1060
1061 /* Clear free list mark bits, in case they got accidentally marked */
1062 /* (or GC_find_leak is set and they were intentionally marked). */
1063 /* Also subtract memory remaining from GC_bytes_found count. */
1064 /* Note that composite objects on free list are cleared. */
1065 /* Thus accidentally marking a free list is not a problem; only */
1066 /* objects on the list itself will be marked, and that's fixed here. */
1067 {
1068 word size; /* current object size */
1069 ptr_t q; /* pointer to current object */
1070 unsigned kind;
1071
1072 for (kind = 0; kind < GC_n_kinds; kind++) {
1073 for (size = 1; size <= MAXOBJGRANULES; size++) {
1074 q = (ptr_t)GC_obj_kinds[kind].ok_freelist[size];
1075 if (q != NULL)
1076 GC_clear_fl_marks(q);
1077 }
1078 }
1079 }
1080
1081 GC_VERBOSE_LOG_PRINTF("Bytes recovered before sweep - f.l. count = %ld\n",
1082 (long)GC_bytes_found);
1083
1084 /* Reconstruct free lists to contain everything not marked */
1085 GC_start_reclaim(FALSE);
1086 GC_DBGLOG_PRINTF("In-use heap: %d%% (%lu KiB pointers + %lu KiB other)\n",
1087 GC_compute_heap_usage_percent(),
1088 TO_KiB_UL(GC_composite_in_use),
1089 TO_KiB_UL(GC_atomic_in_use));
1090 if (GC_is_full_gc) {
1091 GC_used_heap_size_after_full = USED_HEAP_SIZE;
1092 GC_need_full_gc = FALSE;
1093 } else {
1094 GC_need_full_gc = USED_HEAP_SIZE - GC_used_heap_size_after_full
1095 > min_bytes_allocd();
1096 }
1097
1098 GC_VERBOSE_LOG_PRINTF("Immediately reclaimed %ld bytes, heapsize:"
1099 " %lu bytes" IF_USE_MUNMAP(" (%lu unmapped)") "\n",
1100 (long)GC_bytes_found,
1101 (unsigned long)GC_heapsize /*, */
1102 COMMA_IF_USE_MUNMAP((unsigned long)
1103 GC_unmapped_bytes));
1104
1105 /* Reset or increment counters for next cycle */
1106 GC_n_attempts = 0;
1107 GC_is_full_gc = FALSE;
1108 GC_bytes_allocd_before_gc += GC_bytes_allocd;
1109 GC_non_gc_bytes_at_gc = GC_non_gc_bytes;
1110 GC_bytes_allocd = 0;
1111 GC_bytes_dropped = 0;
1112 GC_bytes_freed = 0;
1113 GC_finalizer_bytes_freed = 0;
1114
1115 IF_USE_MUNMAP(GC_unmap_old());
1116
1117 if (GC_on_collection_event)
1118 GC_on_collection_event(GC_EVENT_RECLAIM_END);
1119 # ifndef NO_CLOCK
1120 if (GC_print_stats) {
1121 CLOCK_TYPE done_time;
1122
1123 GET_TIME(done_time);
1124 # if !defined(SMALL_CONFIG) && !defined(GC_NO_FINALIZATION)
1125 /* A convenient place to output finalization statistics. */
1126 GC_print_finalization_stats();
1127 # endif
1128 GC_log_printf("Finalize plus initiate sweep took %lu + %lu msecs\n",
1129 MS_TIME_DIFF(finalize_time,start_time),
1130 MS_TIME_DIFF(done_time,finalize_time));
1131 }
1132 # elif !defined(SMALL_CONFIG) && !defined(GC_NO_FINALIZATION)
1133 if (GC_print_stats)
1134 GC_print_finalization_stats();
1135 # endif
1136 }
1137
1138 /* If stop_func == 0 then GC_default_stop_func is used instead. */
GC_try_to_collect_general(GC_stop_func stop_func,GC_bool force_unmap GC_ATTR_UNUSED)1139 STATIC GC_bool GC_try_to_collect_general(GC_stop_func stop_func,
1140 GC_bool force_unmap GC_ATTR_UNUSED)
1141 {
1142 GC_bool result;
1143 IF_USE_MUNMAP(int old_unmap_threshold;)
1144 IF_CANCEL(int cancel_state;)
1145 DCL_LOCK_STATE;
1146
1147 if (!EXPECT(GC_is_initialized, TRUE)) GC_init();
1148 if (GC_debugging_started) GC_print_all_smashed();
1149 GC_INVOKE_FINALIZERS();
1150 LOCK();
1151 DISABLE_CANCEL(cancel_state);
1152 # ifdef USE_MUNMAP
1153 old_unmap_threshold = GC_unmap_threshold;
1154 if (force_unmap ||
1155 (GC_force_unmap_on_gcollect && old_unmap_threshold > 0))
1156 GC_unmap_threshold = 1; /* unmap as much as possible */
1157 # endif
1158 ENTER_GC();
1159 /* Minimize junk left in my registers */
1160 GC_noop6(0,0,0,0,0,0);
1161 result = GC_try_to_collect_inner(stop_func != 0 ? stop_func :
1162 GC_default_stop_func);
1163 EXIT_GC();
1164 IF_USE_MUNMAP(GC_unmap_threshold = old_unmap_threshold); /* restore */
1165 RESTORE_CANCEL(cancel_state);
1166 UNLOCK();
1167 if (result) {
1168 if (GC_debugging_started) GC_print_all_smashed();
1169 GC_INVOKE_FINALIZERS();
1170 }
1171 return(result);
1172 }
1173
1174 /* Externally callable routines to invoke full, stop-the-world collection. */
GC_try_to_collect(GC_stop_func stop_func)1175 GC_API int GC_CALL GC_try_to_collect(GC_stop_func stop_func)
1176 {
1177 GC_ASSERT(NONNULL_ARG_NOT_NULL(stop_func));
1178 return (int)GC_try_to_collect_general(stop_func, FALSE);
1179 }
1180
GC_gcollect(void)1181 GC_API void GC_CALL GC_gcollect(void)
1182 {
1183 /* 0 is passed as stop_func to get GC_default_stop_func value */
1184 /* while holding the allocation lock (to prevent data races). */
1185 (void)GC_try_to_collect_general(0, FALSE);
1186 if (GC_have_errors) GC_print_all_errors();
1187 }
1188
1189 STATIC word GC_heapsize_at_forced_unmap = 0;
1190
GC_gcollect_and_unmap(void)1191 GC_API void GC_CALL GC_gcollect_and_unmap(void)
1192 {
1193 /* Record current heap size to make heap growth more conservative */
1194 /* afterwards (as if the heap is growing from zero size again). */
1195 GC_heapsize_at_forced_unmap = GC_heapsize;
1196 /* Collect and force memory unmapping to OS. */
1197 (void)GC_try_to_collect_general(GC_never_stop_func, TRUE);
1198 }
1199
1200 GC_INNER word GC_n_heap_sects = 0;
1201 /* Number of sections currently in heap. */
1202
1203 #ifdef USE_PROC_FOR_LIBRARIES
1204 GC_INNER word GC_n_memory = 0;
1205 /* Number of GET_MEM allocated memory sections. */
1206 #endif
1207
1208 #ifdef USE_PROC_FOR_LIBRARIES
1209 /* Add HBLKSIZE aligned, GET_MEM-generated block to GC_our_memory. */
1210 /* Defined to do nothing if USE_PROC_FOR_LIBRARIES not set. */
GC_add_to_our_memory(ptr_t p,size_t bytes)1211 GC_INNER void GC_add_to_our_memory(ptr_t p, size_t bytes)
1212 {
1213 if (0 == p) return;
1214 if (GC_n_memory >= MAX_HEAP_SECTS)
1215 ABORT("Too many GC-allocated memory sections: Increase MAX_HEAP_SECTS");
1216 GC_our_memory[GC_n_memory].hs_start = p;
1217 GC_our_memory[GC_n_memory].hs_bytes = bytes;
1218 GC_n_memory++;
1219 }
1220 #endif
1221
1222 /*
1223 * Use the chunk of memory starting at p of size bytes as part of the heap.
1224 * Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE.
1225 */
GC_add_to_heap(struct hblk * p,size_t bytes)1226 GC_INNER void GC_add_to_heap(struct hblk *p, size_t bytes)
1227 {
1228 hdr * phdr;
1229 word endp;
1230
1231 if (GC_n_heap_sects >= MAX_HEAP_SECTS) {
1232 ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS");
1233 }
1234 while ((word)p <= HBLKSIZE) {
1235 /* Can't handle memory near address zero. */
1236 ++p;
1237 bytes -= HBLKSIZE;
1238 if (0 == bytes) return;
1239 }
1240 endp = (word)p + bytes;
1241 if (endp <= (word)p) {
1242 /* Address wrapped. */
1243 bytes -= HBLKSIZE;
1244 if (0 == bytes) return;
1245 endp -= HBLKSIZE;
1246 }
1247 phdr = GC_install_header(p);
1248 if (0 == phdr) {
1249 /* This is extremely unlikely. Can't add it. This will */
1250 /* almost certainly result in a 0 return from the allocator, */
1251 /* which is entirely appropriate. */
1252 return;
1253 }
1254 GC_ASSERT(endp > (word)p && endp == (word)p + bytes);
1255 GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p;
1256 GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes;
1257 GC_n_heap_sects++;
1258 phdr -> hb_sz = bytes;
1259 phdr -> hb_flags = 0;
1260 GC_freehblk(p);
1261 GC_heapsize += bytes;
1262
1263 /* Normally the caller calculates a new GC_collect_at_heapsize,
1264 * but this is also called directly from GC_scratch_recycle_inner, so
1265 * adjust here. It will be recalculated when called from
1266 * GC_expand_hp_inner.
1267 */
1268 GC_collect_at_heapsize += bytes;
1269 if (GC_collect_at_heapsize < GC_heapsize /* wrapped */)
1270 GC_collect_at_heapsize = GC_WORD_MAX;
1271
1272 if ((word)p <= (word)GC_least_plausible_heap_addr
1273 || GC_least_plausible_heap_addr == 0) {
1274 GC_least_plausible_heap_addr = (void *)((ptr_t)p - sizeof(word));
1275 /* Making it a little smaller than necessary prevents */
1276 /* us from getting a false hit from the variable */
1277 /* itself. There's some unintentional reflection */
1278 /* here. */
1279 }
1280 if ((word)p + bytes >= (word)GC_greatest_plausible_heap_addr) {
1281 GC_greatest_plausible_heap_addr = (void *)endp;
1282 }
1283 }
1284
1285 #if !defined(NO_DEBUGGING)
GC_print_heap_sects(void)1286 void GC_print_heap_sects(void)
1287 {
1288 unsigned i;
1289
1290 GC_printf("Total heap size: %lu" IF_USE_MUNMAP(" (%lu unmapped)") "\n",
1291 (unsigned long)GC_heapsize /*, */
1292 COMMA_IF_USE_MUNMAP((unsigned long)GC_unmapped_bytes));
1293
1294 for (i = 0; i < GC_n_heap_sects; i++) {
1295 ptr_t start = GC_heap_sects[i].hs_start;
1296 size_t len = GC_heap_sects[i].hs_bytes;
1297 struct hblk *h;
1298 unsigned nbl = 0;
1299
1300 for (h = (struct hblk *)start; (word)h < (word)(start + len); h++) {
1301 if (GC_is_black_listed(h, HBLKSIZE)) nbl++;
1302 }
1303 GC_printf("Section %d from %p to %p %u/%lu blacklisted\n",
1304 i, (void *)start, (void *)&start[len],
1305 nbl, (unsigned long)divHBLKSZ(len));
1306 }
1307 }
1308 #endif
1309
1310 void * GC_least_plausible_heap_addr = (void *)GC_WORD_MAX;
1311 void * GC_greatest_plausible_heap_addr = 0;
1312
GC_max(word x,word y)1313 GC_INLINE word GC_max(word x, word y)
1314 {
1315 return(x > y? x : y);
1316 }
1317
GC_min(word x,word y)1318 GC_INLINE word GC_min(word x, word y)
1319 {
1320 return(x < y? x : y);
1321 }
1322
1323 STATIC word GC_max_heapsize = 0;
1324
GC_set_max_heap_size(GC_word n)1325 GC_API void GC_CALL GC_set_max_heap_size(GC_word n)
1326 {
1327 GC_max_heapsize = n;
1328 }
1329
1330 GC_word GC_max_retries = 0;
1331
1332 /* This explicitly increases the size of the heap. It is used */
1333 /* internally, but may also be invoked from GC_expand_hp by the user. */
1334 /* The argument is in units of HBLKSIZE (tiny values are rounded up). */
1335 /* Returns FALSE on failure. */
GC_expand_hp_inner(word n)1336 GC_INNER GC_bool GC_expand_hp_inner(word n)
1337 {
1338 size_t bytes;
1339 struct hblk * space;
1340 word expansion_slop; /* Number of bytes by which we expect the */
1341 /* heap to expand soon. */
1342
1343 if (n < MINHINCR) n = MINHINCR;
1344 bytes = ROUNDUP_PAGESIZE((size_t)n * HBLKSIZE);
1345 if (GC_max_heapsize != 0
1346 && (GC_max_heapsize < (word)bytes
1347 || GC_heapsize > GC_max_heapsize - (word)bytes)) {
1348 /* Exceeded self-imposed limit */
1349 return(FALSE);
1350 }
1351 space = GET_MEM(bytes);
1352 GC_add_to_our_memory((ptr_t)space, bytes);
1353 if (space == 0) {
1354 WARN("Failed to expand heap by %" WARN_PRIdPTR " bytes\n",
1355 (word)bytes);
1356 return(FALSE);
1357 }
1358 GC_INFOLOG_PRINTF("Grow heap to %lu KiB after %lu bytes allocated\n",
1359 TO_KiB_UL(GC_heapsize + (word)bytes),
1360 (unsigned long)GC_bytes_allocd);
1361 /* Adjust heap limits generously for blacklisting to work better. */
1362 /* GC_add_to_heap performs minimal adjustment needed for */
1363 /* correctness. */
1364 expansion_slop = min_bytes_allocd() + 4*MAXHINCR*HBLKSIZE;
1365 if ((GC_last_heap_addr == 0 && !((word)space & SIGNB))
1366 || (GC_last_heap_addr != 0
1367 && (word)GC_last_heap_addr < (word)space)) {
1368 /* Assume the heap is growing up */
1369 word new_limit = (word)space + (word)bytes + expansion_slop;
1370 if (new_limit > (word)space) {
1371 GC_greatest_plausible_heap_addr =
1372 (void *)GC_max((word)GC_greatest_plausible_heap_addr,
1373 (word)new_limit);
1374 }
1375 } else {
1376 /* Heap is growing down */
1377 word new_limit = (word)space - expansion_slop;
1378 if (new_limit < (word)space) {
1379 GC_least_plausible_heap_addr =
1380 (void *)GC_min((word)GC_least_plausible_heap_addr,
1381 (word)space - expansion_slop);
1382 }
1383 }
1384 GC_prev_heap_addr = GC_last_heap_addr;
1385 GC_last_heap_addr = (ptr_t)space;
1386 GC_add_to_heap(space, bytes);
1387 /* Force GC before we are likely to allocate past expansion_slop */
1388 GC_collect_at_heapsize =
1389 GC_heapsize + expansion_slop - 2*MAXHINCR*HBLKSIZE;
1390 if (GC_collect_at_heapsize < GC_heapsize /* wrapped */)
1391 GC_collect_at_heapsize = GC_WORD_MAX;
1392 if (GC_on_heap_resize)
1393 (*GC_on_heap_resize)(GC_heapsize);
1394
1395 return(TRUE);
1396 }
1397
1398 /* Really returns a bool, but it's externally visible, so that's clumsy. */
1399 /* Arguments is in bytes. Includes GC_init() call. */
GC_expand_hp(size_t bytes)1400 GC_API int GC_CALL GC_expand_hp(size_t bytes)
1401 {
1402 int result;
1403 DCL_LOCK_STATE;
1404
1405 if (!EXPECT(GC_is_initialized, TRUE)) GC_init();
1406 LOCK();
1407 result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes));
1408 if (result) GC_requested_heapsize += bytes;
1409 UNLOCK();
1410 return(result);
1411 }
1412
1413 word GC_fo_entries = 0; /* used also in extra/MacOS.c */
1414
1415 GC_INNER unsigned GC_fail_count = 0;
1416 /* How many consecutive GC/expansion failures? */
1417 /* Reset by GC_allochblk. */
1418
1419 static word last_fo_entries = 0;
1420 static word last_bytes_finalized = 0;
1421
1422 /* Collect or expand heap in an attempt make the indicated number of */
1423 /* free blocks available. Should be called until the blocks are */
1424 /* available (setting retry value to TRUE unless this is the first call */
1425 /* in a loop) or until it fails by returning FALSE. */
GC_collect_or_expand(word needed_blocks,GC_bool ignore_off_page,GC_bool retry)1426 GC_INNER GC_bool GC_collect_or_expand(word needed_blocks,
1427 GC_bool ignore_off_page,
1428 GC_bool retry)
1429 {
1430 GC_bool gc_not_stopped = TRUE;
1431 word blocks_to_get;
1432 IF_CANCEL(int cancel_state;)
1433
1434 DISABLE_CANCEL(cancel_state);
1435 if (!GC_incremental && !GC_dont_gc &&
1436 ((GC_dont_expand && GC_bytes_allocd > 0)
1437 || (GC_fo_entries > (last_fo_entries + 500)
1438 && (last_bytes_finalized | GC_bytes_finalized) != 0)
1439 || GC_should_collect())) {
1440 /* Try to do a full collection using 'default' stop_func (unless */
1441 /* nothing has been allocated since the latest collection or heap */
1442 /* expansion is disabled). */
1443 gc_not_stopped = GC_try_to_collect_inner(
1444 GC_bytes_allocd > 0 && (!GC_dont_expand || !retry) ?
1445 GC_default_stop_func : GC_never_stop_func);
1446 if (gc_not_stopped == TRUE || !retry) {
1447 /* Either the collection hasn't been aborted or this is the */
1448 /* first attempt (in a loop). */
1449 last_fo_entries = GC_fo_entries;
1450 last_bytes_finalized = GC_bytes_finalized;
1451 RESTORE_CANCEL(cancel_state);
1452 return(TRUE);
1453 }
1454 }
1455
1456 blocks_to_get = (GC_heapsize - GC_heapsize_at_forced_unmap)
1457 / (HBLKSIZE * GC_free_space_divisor)
1458 + needed_blocks;
1459 if (blocks_to_get > MAXHINCR) {
1460 word slop;
1461
1462 /* Get the minimum required to make it likely that we can satisfy */
1463 /* the current request in the presence of black-listing. */
1464 /* This will probably be more than MAXHINCR. */
1465 if (ignore_off_page) {
1466 slop = 4;
1467 } else {
1468 slop = 2 * divHBLKSZ(BL_LIMIT);
1469 if (slop > needed_blocks) slop = needed_blocks;
1470 }
1471 if (needed_blocks + slop > MAXHINCR) {
1472 blocks_to_get = needed_blocks + slop;
1473 } else {
1474 blocks_to_get = MAXHINCR;
1475 }
1476 if (blocks_to_get > divHBLKSZ(GC_WORD_MAX))
1477 blocks_to_get = divHBLKSZ(GC_WORD_MAX);
1478 }
1479
1480 if (!GC_expand_hp_inner(blocks_to_get)
1481 && (blocks_to_get == needed_blocks
1482 || !GC_expand_hp_inner(needed_blocks))) {
1483 if (gc_not_stopped == FALSE) {
1484 /* Don't increment GC_fail_count here (and no warning). */
1485 GC_gcollect_inner();
1486 GC_ASSERT(GC_bytes_allocd == 0);
1487 } else if (GC_fail_count++ < GC_max_retries) {
1488 WARN("Out of Memory! Trying to continue...\n", 0);
1489 GC_gcollect_inner();
1490 } else {
1491 # if !defined(AMIGA) || !defined(GC_AMIGA_FASTALLOC)
1492 WARN("Out of Memory! Heap size: %" WARN_PRIdPTR " MiB."
1493 " Returning NULL!\n", (GC_heapsize - GC_unmapped_bytes) >> 20);
1494 # endif
1495 RESTORE_CANCEL(cancel_state);
1496 return(FALSE);
1497 }
1498 } else if (GC_fail_count) {
1499 GC_COND_LOG_PRINTF("Memory available again...\n");
1500 }
1501 RESTORE_CANCEL(cancel_state);
1502 return(TRUE);
1503 }
1504
1505 /*
1506 * Make sure the object free list for size gran (in granules) is not empty.
1507 * Return a pointer to the first object on the free list.
1508 * The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER.
1509 */
GC_allocobj(size_t gran,int kind)1510 GC_INNER ptr_t GC_allocobj(size_t gran, int kind)
1511 {
1512 void ** flh = &(GC_obj_kinds[kind].ok_freelist[gran]);
1513 GC_bool tried_minor = FALSE;
1514 GC_bool retry = FALSE;
1515
1516 GC_ASSERT(I_HOLD_LOCK());
1517 if (gran == 0) return(0);
1518
1519 while (*flh == 0) {
1520 ENTER_GC();
1521 # ifndef GC_DISABLE_INCREMENTAL
1522 if (GC_incremental && GC_time_limit != GC_TIME_UNLIMITED) {
1523 /* True incremental mode, not just generational. */
1524 /* Do our share of marking work. */
1525 GC_collect_a_little_inner(1);
1526 }
1527 # endif
1528 /* Sweep blocks for objects of this size */
1529 GC_ASSERT(!GC_is_full_gc
1530 || NULL == GC_obj_kinds[kind].ok_reclaim_list
1531 || NULL == GC_obj_kinds[kind].ok_reclaim_list[gran]);
1532 GC_continue_reclaim(gran, kind);
1533 EXIT_GC();
1534 if (*flh == 0) {
1535 GC_new_hblk(gran, kind);
1536 if (*flh == 0) {
1537 ENTER_GC();
1538 if (GC_incremental && GC_time_limit == GC_TIME_UNLIMITED
1539 && !tried_minor) {
1540 GC_collect_a_little_inner(1);
1541 tried_minor = TRUE;
1542 } else {
1543 if (!GC_collect_or_expand(1, FALSE, retry)) {
1544 EXIT_GC();
1545 return(0);
1546 }
1547 retry = TRUE;
1548 }
1549 EXIT_GC();
1550 }
1551 }
1552 }
1553 /* Successful allocation; reset failure count. */
1554 GC_fail_count = 0;
1555
1556 return (ptr_t)(*flh);
1557 }
1558