Annotation of OpenXM_contrib2/asir2000/gc/alloc.c, Revision 1.1.1.1
1.1 noro 1: /*
2: * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
3: * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
4: * Copyright (c) 1998 by Silicon Graphics. All rights reserved.
5: *
6: * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
7: * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
8: *
9: * Permission is hereby granted to use or copy this program
10: * for any purpose, provided the above notices are retained on all copies.
11: * Permission to modify the code and to distribute modified code is granted,
12: * provided the above notices are retained, and a notice that the code was
13: * modified is included with the above copyright notice.
14: *
15: */
16:
17:
18: # include "gc_priv.h"
19:
20: # include <stdio.h>
21: # ifndef MACOS
22: # include <signal.h>
23: # include <sys/types.h>
24: # endif
25:
26: void GC_timerstart(),GC_timerstop();
27:
28: /*
29: * Separate free lists are maintained for different sized objects
30: * up to MAXOBJSZ.
31: * The call GC_allocobj(i,k) ensures that the freelist for
32: * kind k objects of size i points to a non-empty
33: * free list. It returns a pointer to the first entry on the free list.
34: * In a single-threaded world, GC_allocobj may be called to allocate
35: * an object of (small) size i as follows:
36: *
37: * opp = &(GC_objfreelist[i]);
38: * if (*opp == 0) GC_allocobj(i, NORMAL);
39: * ptr = *opp;
40: * *opp = obj_link(ptr);
41: *
42: * Note that this is very fast if the free list is non-empty; it should
43: * only involve the execution of 4 or 5 simple instructions.
44: * All composite objects on freelists are cleared, except for
45: * their first word.
46: */
47:
48: /*
49: * The allocator uses GC_allochblk to allocate large chunks of objects.
50: * These chunks all start on addresses which are multiples of
51: * HBLKSZ. Each allocated chunk has an associated header,
52: * which can be located quickly based on the address of the chunk.
53: * (See headers.c for details.)
54: * This makes it possible to check quickly whether an
55: * arbitrary address corresponds to an object administered by the
56: * allocator.
57: */
58:
59: word GC_non_gc_bytes = 0; /* Number of bytes not intended to be collected */
60:
61: word GC_gc_no = 0;
62:
63: #ifndef SMALL_CONFIG
64: int GC_incremental = 0; /* By default, stop the world. */
65: #endif
66:
67: int GC_full_freq = 4; /* Every 5th collection is a full */
68: /* collection. */
69:
70: char * GC_copyright[] =
71: {"Copyright 1988,1989 Hans-J. Boehm and Alan J. Demers ",
72: "Copyright (c) 1991-1995 by Xerox Corporation. All rights reserved. ",
73: "Copyright (c) 1996-1998 by Silicon Graphics. All rights reserved. ",
74: "THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY",
75: " EXPRESSED OR IMPLIED. ANY USE IS AT YOUR OWN RISK.",
76: "See source code for details." };
77:
78: # include "version.h"
79:
80: /* some more variables */
81:
82: extern signed_word GC_mem_found; /* Number of reclaimed longwords */
83: /* after garbage collection */
84:
85: GC_bool GC_dont_expand = 0;
86:
87: word GC_free_space_numerator = 1;
88: word GC_free_space_divisor = 3;
89:
90: extern GC_bool GC_collection_in_progress();
91: /* Collection is in progress, or was abandoned. */
92:
93: int GC_never_stop_func GC_PROTO((void)) { return(0); }
94:
95: CLOCK_TYPE GC_start_time; /* Time at which we stopped world. */
96: /* used only in GC_timeout_stop_func. */
97:
98: int GC_n_attempts = 0; /* Number of attempts at finishing */
99: /* collection within TIME_LIMIT */
100:
101: #ifdef SMALL_CONFIG
102: # define GC_timeout_stop_func GC_never_stop_func
103: #else
104: int GC_timeout_stop_func GC_PROTO((void))
105: {
106: CLOCK_TYPE current_time;
107: static unsigned count = 0;
108: unsigned long time_diff;
109:
110: if ((count++ & 3) != 0) return(0);
111: GET_TIME(current_time);
112: time_diff = MS_TIME_DIFF(current_time,GC_start_time);
113: if (time_diff >= TIME_LIMIT) {
114: # ifdef PRINTSTATS
115: GC_printf0("Abandoning stopped marking after ");
116: GC_printf1("%lu msecs", (unsigned long)time_diff);
117: GC_printf1("(attempt %d)\n", (unsigned long) GC_n_attempts);
118: # endif
119: return(1);
120: }
121: return(0);
122: }
123: #endif /* !SMALL_CONFIG */
124:
125: /* Return the minimum number of words that must be allocated between */
126: /* collections to amortize the collection cost. */
127: static word min_words_allocd()
128: {
129: # ifdef THREADS
130: /* We punt, for now. */
131: register signed_word stack_size = 10000;
132: # else
133: int dummy;
134: register signed_word stack_size = (ptr_t)(&dummy) - GC_stackbottom;
135: # endif
136: word total_root_size; /* includes double stack size, */
137: /* since the stack is expensive */
138: /* to scan. */
139: word scan_size; /* Estimate of memory to be scanned */
140: /* during normal GC. */
141:
142: if (stack_size < 0) stack_size = -stack_size;
143: total_root_size = 2 * stack_size + GC_root_size;
144: scan_size = BYTES_TO_WORDS(GC_heapsize - GC_large_free_bytes
145: + (GC_large_free_bytes >> 2)
146: /* use a bit more of large empty heap */
147: + total_root_size);
148: if (GC_incremental) {
149: return (scan_size*GC_free_space_numerator) / (2 * GC_free_space_divisor);
150: } else {
151: return (scan_size*GC_free_space_numerator) / GC_free_space_divisor;
152: }
153: }
154:
155: /* Return the number of words allocated, adjusted for explicit storage */
156: /* management, etc.. This number is used in deciding when to trigger */
157: /* collections. */
158: word GC_adj_words_allocd()
159: {
160: register signed_word result;
161: register signed_word expl_managed =
162: BYTES_TO_WORDS((long)GC_non_gc_bytes
163: - (long)GC_non_gc_bytes_at_gc);
164:
165: /* Don't count what was explicitly freed, or newly allocated for */
166: /* explicit management. Note that deallocating an explicitly */
167: /* managed object should not alter result, assuming the client */
168: /* is playing by the rules. */
169: result = (signed_word)GC_words_allocd
170: - (signed_word)GC_mem_freed - expl_managed;
171: if (result > (signed_word)GC_words_allocd) {
172: result = GC_words_allocd;
173: /* probably client bug or unfortunate scheduling */
174: }
175: result += GC_words_finalized;
176: /* We count objects enqueued for finalization as though they */
177: /* had been reallocated this round. Finalization is user */
178: /* visible progress. And if we don't count this, we have */
179: /* stability problems for programs that finalize all objects. */
180: result += GC_words_wasted;
181: /* This doesn't reflect useful work. But if there is lots of */
182: /* new fragmentation, the same is probably true of the heap, */
183: /* and the collection will be correspondingly cheaper. */
184: if (result < (signed_word)(GC_words_allocd >> 3)) {
185: /* Always count at least 1/8 of the allocations. We don't want */
186: /* to collect too infrequently, since that would inhibit */
187: /* coalescing of free storage blocks. */
188: /* This also makes us partially robust against client bugs. */
189: return(GC_words_allocd >> 3);
190: } else {
191: return(result);
192: }
193: }
194:
195:
196: /* Clear up a few frames worth of garbage left at the top of the stack. */
197: /* This is used to prevent us from accidentally treating garbade left */
198: /* on the stack by other parts of the collector as roots. This */
199: /* differs from the code in misc.c, which actually tries to keep the */
200: /* stack clear of long-lived, client-generated garbage. */
201: void GC_clear_a_few_frames()
202: {
203: # define NWORDS 64
204: word frames[NWORDS];
205: register int i;
206:
207: for (i = 0; i < NWORDS; i++) frames[i] = 0;
208: }
209:
210: /* Have we allocated enough to amortize a collection? */
211: GC_bool GC_should_collect()
212: {
213: return(GC_adj_words_allocd() >= min_words_allocd());
214: }
215:
216: void GC_notify_full_gc()
217: {
218: if (GC_start_call_back != (void (*)())0) {
219: (*GC_start_call_back)();
220: }
221: }
222:
223: /*
224: * Initiate a garbage collection if appropriate.
225: * Choose judiciously
226: * between partial, full, and stop-world collections.
227: * Assumes lock held, signals disabled.
228: */
229: void GC_maybe_gc()
230: {
231: static int n_partial_gcs = 0;
232: GC_bool is_full_gc = FALSE;
233:
234: if (GC_should_collect()) {
235: if (!GC_incremental) {
236: GC_notify_full_gc();
237: GC_gcollect_inner();
238: n_partial_gcs = 0;
239: return;
240: } else if (n_partial_gcs >= GC_full_freq) {
241: # ifdef PRINTSTATS
242: GC_printf2(
243: "***>Full mark for collection %lu after %ld allocd bytes\n",
244: (unsigned long) GC_gc_no+1,
245: (long)WORDS_TO_BYTES(GC_words_allocd));
246: # endif
247: GC_promote_black_lists();
248: (void)GC_reclaim_all((GC_stop_func)0, TRUE);
249: GC_clear_marks();
250: n_partial_gcs = 0;
251: GC_notify_full_gc();
252: is_full_gc = TRUE;
253: } else {
254: n_partial_gcs++;
255: }
256: /* We try to mark with the world stopped. */
257: /* If we run out of time, this turns into */
258: /* incremental marking. */
259: GET_TIME(GC_start_time);
260: if (GC_stopped_mark(GC_timeout_stop_func)) {
261: # ifdef SAVE_CALL_CHAIN
262: GC_save_callers(GC_last_stack);
263: # endif
264: GC_finish_collection();
265: } else {
266: if (!is_full_gc) {
267: /* Count this as the first attempt */
268: GC_n_attempts++;
269: }
270: }
271: }
272: }
273:
274:
275: /*
276: * Stop the world garbage collection. Assumes lock held, signals disabled.
277: * If stop_func is not GC_never_stop_func, then abort if stop_func returns TRUE.
278: */
279: GC_bool GC_try_to_collect_inner(stop_func)
280: GC_stop_func stop_func;
281: {
282: if (GC_incremental && GC_collection_in_progress()) {
283: # ifdef PRINTSTATS
284: GC_printf0(
285: "GC_try_to_collect_inner: finishing collection in progress\n");
286: # endif /* PRINTSTATS */
287: /* Just finish collection already in progress. */
288: while(GC_collection_in_progress()) {
289: if (stop_func()) return(FALSE);
290: GC_collect_a_little_inner(1);
291: }
292: }
293: # ifdef PRINTSTATS
294: GC_printf2(
295: "Initiating full world-stop collection %lu after %ld allocd bytes\n",
296: (unsigned long) GC_gc_no+1,
297: (long)WORDS_TO_BYTES(GC_words_allocd));
298: # endif
299: GC_promote_black_lists();
300: /* Make sure all blocks have been reclaimed, so sweep routines */
301: /* don't see cleared mark bits. */
302: /* If we're guaranteed to finish, then this is unnecessary. */
303: if (stop_func != GC_never_stop_func
304: && !GC_reclaim_all(stop_func, FALSE)) {
305: /* Aborted. So far everything is still consistent. */
306: return(FALSE);
307: }
308: GC_invalidate_mark_state(); /* Flush mark stack. */
309: GC_clear_marks();
310: # ifdef SAVE_CALL_CHAIN
311: GC_save_callers(GC_last_stack);
312: # endif
313: if (!GC_stopped_mark(stop_func)) {
314: if (!GC_incremental) {
315: /* We're partially done and have no way to complete or use */
316: /* current work. Reestablish invariants as cheaply as */
317: /* possible. */
318: GC_invalidate_mark_state();
319: GC_unpromote_black_lists();
320: } /* else we claim the world is already still consistent. We'll */
321: /* finish incrementally. */
322: return(FALSE);
323: }
324: GC_finish_collection();
325: return(TRUE);
326: }
327:
328:
329:
330: /*
331: * Perform n units of garbage collection work. A unit is intended to touch
332: * roughly GC_RATE pages. Every once in a while, we do more than that.
333: * This needa to be a fairly large number with our current incremental
334: * GC strategy, since otherwise we allocate too much during GC, and the
335: * cleanup gets expensive.
336: */
337: # define GC_RATE 10
338: # define MAX_PRIOR_ATTEMPTS 1
339: /* Maximum number of prior attempts at world stop marking */
340: /* A value of 1 means that we finish the seconf time, no matter */
341: /* how long it takes. Doesn't count the initial root scan */
342: /* for a full GC. */
343:
344: int GC_deficit = 0; /* The number of extra calls to GC_mark_some */
345: /* that we have made. */
346:
347: void GC_collect_a_little_inner(n)
348: int n;
349: {
350: register int i;
351:
352: if (GC_incremental && GC_collection_in_progress()) {
353: for (i = GC_deficit; i < GC_RATE*n; i++) {
354: if (GC_mark_some((ptr_t)0)) {
355: /* Need to finish a collection */
356: # ifdef SAVE_CALL_CHAIN
357: GC_save_callers(GC_last_stack);
358: # endif
359: if (GC_n_attempts < MAX_PRIOR_ATTEMPTS) {
360: GET_TIME(GC_start_time);
361: if (!GC_stopped_mark(GC_timeout_stop_func)) {
362: GC_n_attempts++;
363: break;
364: }
365: } else {
366: (void)GC_stopped_mark(GC_never_stop_func);
367: }
368: GC_finish_collection();
369: break;
370: }
371: }
372: if (GC_deficit > 0) GC_deficit -= GC_RATE*n;
373: if (GC_deficit < 0) GC_deficit = 0;
374: } else {
375: GC_maybe_gc();
376: }
377: }
378:
379: int GC_collect_a_little GC_PROTO(())
380: {
381: int result;
382: DCL_LOCK_STATE;
383:
384: DISABLE_SIGNALS();
385: LOCK();
386: GC_collect_a_little_inner(1);
387: result = (int)GC_collection_in_progress();
388: UNLOCK();
389: ENABLE_SIGNALS();
390: return(result);
391: }
392:
393: /*
394: * Assumes lock is held, signals are disabled.
395: * We stop the world.
396: * If stop_func() ever returns TRUE, we may fail and return FALSE.
397: * Increment GC_gc_no if we succeed.
398: */
399: GC_bool GC_stopped_mark(stop_func)
400: GC_stop_func stop_func;
401: {
402: register int i;
403: int dummy;
404: # ifdef PRINTSTATS
405: CLOCK_TYPE start_time, current_time;
406: # endif
407:
408: STOP_WORLD();
409: GC_timerstart();
410: # ifdef PRINTSTATS
411: GET_TIME(start_time);
412: GC_printf1("--> Marking for collection %lu ",
413: (unsigned long) GC_gc_no + 1);
414: GC_printf2("after %lu allocd bytes + %lu wasted bytes\n",
415: (unsigned long) WORDS_TO_BYTES(GC_words_allocd),
416: (unsigned long) WORDS_TO_BYTES(GC_words_wasted));
417: # endif
418:
419: /* Mark from all roots. */
420: /* Minimize junk left in my registers and on the stack */
421: GC_clear_a_few_frames();
422: GC_noop(0,0,0,0,0,0);
423: GC_initiate_gc();
424: for(i = 0;;i++) {
425: if ((*stop_func)()) {
426: # ifdef PRINTSTATS
427: GC_printf0("Abandoned stopped marking after ");
428: GC_printf1("%lu iterations\n",
429: (unsigned long)i);
430: # endif
431: GC_timerstop();
432: GC_deficit = i; /* Give the mutator a chance. */
433: START_WORLD();
434: return(FALSE);
435: }
436: if (GC_mark_some((ptr_t)(&dummy))) break;
437: }
438:
439: GC_gc_no++;
440: # ifdef PRINTSTATS
441: GC_printf2("Collection %lu reclaimed %ld bytes",
442: (unsigned long) GC_gc_no - 1,
443: (long)WORDS_TO_BYTES(GC_mem_found));
444: GC_printf1(" ---> heapsize = %lu bytes\n",
445: (unsigned long) GC_heapsize);
446: /* Printf arguments may be pushed in funny places. Clear the */
447: /* space. */
448: GC_printf0("");
449: # endif
450:
451: /* Check all debugged objects for consistency */
452: if (GC_debugging_started) {
453: (*GC_check_heap)();
454: }
455:
456: # ifdef PRINTTIMES
457: GET_TIME(current_time);
458: GC_printf1("World-stopped marking took %lu msecs\n",
459: MS_TIME_DIFF(current_time,start_time));
460: # endif
461: GC_timerstop();
462: START_WORLD();
463: return(TRUE);
464: }
465:
466:
467: /* Finish up a collection. Assumes lock is held, signals are disabled, */
468: /* but the world is otherwise running. */
469: void GC_finish_collection()
470: {
471: # ifdef PRINTTIMES
472: CLOCK_TYPE start_time;
473: CLOCK_TYPE finalize_time;
474: CLOCK_TYPE done_time;
475:
476: GET_TIME(start_time);
477: finalize_time = start_time;
478: # endif
479: GC_timerstart();
480:
481: # ifdef GATHERSTATS
482: GC_mem_found = 0;
483: # endif
484: # ifdef FIND_LEAK
485: /* Mark all objects on the free list. All objects should be */
486: /* marked when we're done. */
487: {
488: register word size; /* current object size */
489: register ptr_t p; /* pointer to current object */
490: register struct hblk * h; /* pointer to block containing *p */
491: register hdr * hhdr;
492: register int word_no; /* "index" of *p in *q */
493: int kind;
494:
495: for (kind = 0; kind < GC_n_kinds; kind++) {
496: for (size = 1; size <= MAXOBJSZ; size++) {
497: for (p= GC_obj_kinds[kind].ok_freelist[size];
498: p != 0; p=obj_link(p)){
499: h = HBLKPTR(p);
500: hhdr = HDR(h);
501: word_no = (((word *)p) - ((word *)h));
502: set_mark_bit_from_hdr(hhdr, word_no);
503: }
504: }
505: }
506: }
507: /* Check that everything is marked */
508: GC_start_reclaim(TRUE);
509: # else
510:
511: GC_finalize();
512: # ifdef STUBBORN_ALLOC
513: GC_clean_changing_list();
514: # endif
515:
516: # ifdef PRINTTIMES
517: GET_TIME(finalize_time);
518: # endif
519:
520: /* Clear free list mark bits, in case they got accidentally marked */
521: /* Note: HBLKPTR(p) == pointer to head of block containing *p */
522: /* Also subtract memory remaining from GC_mem_found count. */
523: /* Note that composite objects on free list are cleared. */
524: /* Thus accidentally marking a free list is not a problem; only */
525: /* objects on the list itself will be marked, and that's fixed here. */
526: {
527: register word size; /* current object size */
528: register ptr_t p; /* pointer to current object */
529: register struct hblk * h; /* pointer to block containing *p */
530: register hdr * hhdr;
531: register int word_no; /* "index" of *p in *q */
532: int kind;
533:
534: for (kind = 0; kind < GC_n_kinds; kind++) {
535: for (size = 1; size <= MAXOBJSZ; size++) {
536: for (p= GC_obj_kinds[kind].ok_freelist[size];
537: p != 0; p=obj_link(p)){
538: h = HBLKPTR(p);
539: hhdr = HDR(h);
540: word_no = (((word *)p) - ((word *)h));
541: clear_mark_bit_from_hdr(hhdr, word_no);
542: # ifdef GATHERSTATS
543: GC_mem_found -= size;
544: # endif
545: }
546: }
547: }
548: }
549:
550:
551: # ifdef PRINTSTATS
552: GC_printf1("Bytes recovered before sweep - f.l. count = %ld\n",
553: (long)WORDS_TO_BYTES(GC_mem_found));
554: # endif
555:
556: /* Reconstruct free lists to contain everything not marked */
557: GC_start_reclaim(FALSE);
558:
559: # endif /* !FIND_LEAK */
560:
561: # ifdef PRINTSTATS
562: GC_printf2(
563: "Immediately reclaimed %ld bytes in heap of size %lu bytes",
564: (long)WORDS_TO_BYTES(GC_mem_found),
565: (unsigned long)GC_heapsize);
566: # ifdef USE_MUNMAP
567: GC_printf1("(%lu unmapped)", GC_unmapped_bytes);
568: # endif
569: GC_printf2(
570: "\n%lu (atomic) + %lu (composite) collectable bytes in use\n",
571: (unsigned long)WORDS_TO_BYTES(GC_atomic_in_use),
572: (unsigned long)WORDS_TO_BYTES(GC_composite_in_use));
573: # endif
574:
575: GC_n_attempts = 0;
576: /* Reset or increment counters for next cycle */
577: GC_words_allocd_before_gc += GC_words_allocd;
578: GC_non_gc_bytes_at_gc = GC_non_gc_bytes;
579: GC_words_allocd = 0;
580: GC_words_wasted = 0;
581: GC_mem_freed = 0;
582:
583: # ifdef USE_MUNMAP
584: GC_unmap_old();
585: # endif
586: # ifdef PRINTTIMES
587: GET_TIME(done_time);
588: GC_printf2("Finalize + initiate sweep took %lu + %lu msecs\n",
589: MS_TIME_DIFF(finalize_time,start_time),
590: MS_TIME_DIFF(done_time,finalize_time));
591: # endif
592: GC_timerstop();
593: }
594:
595: /* Externally callable routine to invoke full, stop-world collection */
596: # if defined(__STDC__) || defined(__cplusplus)
597: int GC_try_to_collect(GC_stop_func stop_func)
598: # else
599: int GC_try_to_collect(stop_func)
600: GC_stop_func stop_func;
601: # endif
602: {
603: int result;
604: DCL_LOCK_STATE;
605:
606: GC_INVOKE_FINALIZERS();
607: DISABLE_SIGNALS();
608: LOCK();
609: ENTER_GC();
610: if (!GC_is_initialized) GC_init_inner();
611: /* Minimize junk left in my registers */
612: GC_noop(0,0,0,0,0,0);
613: result = (int)GC_try_to_collect_inner(stop_func);
614: EXIT_GC();
615: UNLOCK();
616: ENABLE_SIGNALS();
617: if(result) GC_INVOKE_FINALIZERS();
618: return(result);
619: }
620:
621: void GC_gcollect GC_PROTO(())
622: {
623: GC_notify_full_gc();
624: (void)GC_try_to_collect(GC_never_stop_func);
625: }
626:
627: word GC_n_heap_sects = 0; /* Number of sections currently in heap. */
628:
629: /*
630: * Use the chunk of memory starting at p of size bytes as part of the heap.
631: * Assumes p is HBLKSIZE aligned, and bytes is a multiple of HBLKSIZE.
632: */
633: void GC_add_to_heap(p, bytes)
634: struct hblk *p;
635: word bytes;
636: {
637: word words;
638: hdr * phdr;
639:
640: if (GC_n_heap_sects >= MAX_HEAP_SECTS) {
641: ABORT("Too many heap sections: Increase MAXHINCR or MAX_HEAP_SECTS");
642: }
643: if (!GC_install_header(p)) {
644: /* This is extremely unlikely. Can't add it. This will */
645: /* almost certainly result in a 0 return from the allocator, */
646: /* which is entirely appropriate. */
647: return;
648: }
649: GC_heap_sects[GC_n_heap_sects].hs_start = (ptr_t)p;
650: GC_heap_sects[GC_n_heap_sects].hs_bytes = bytes;
651: GC_n_heap_sects++;
652: words = BYTES_TO_WORDS(bytes - HDR_BYTES);
653: phdr = HDR(p);
654: phdr -> hb_sz = words;
655: phdr -> hb_map = (char *)1; /* A value != GC_invalid_map */
656: phdr -> hb_flags = 0;
657: GC_freehblk(p);
658: GC_heapsize += bytes;
659: if ((ptr_t)p <= GC_least_plausible_heap_addr
660: || GC_least_plausible_heap_addr == 0) {
661: GC_least_plausible_heap_addr = (ptr_t)p - sizeof(word);
662: /* Making it a little smaller than necessary prevents */
663: /* us from getting a false hit from the variable */
664: /* itself. There's some unintentional reflection */
665: /* here. */
666: }
667: if ((ptr_t)p + bytes >= GC_greatest_plausible_heap_addr) {
668: GC_greatest_plausible_heap_addr = (ptr_t)p + bytes;
669: }
670: }
671:
672: #ifdef PRESERVE_LAST
673:
674: GC_bool GC_protect_last_block = FALSE;
675:
676: GC_bool GC_in_last_heap_sect(p)
677: ptr_t p;
678: {
679: struct HeapSect * last_heap_sect;
680: ptr_t start;
681: ptr_t end;
682:
683: if (!GC_protect_last_block) return FALSE;
684: last_heap_sect = &(GC_heap_sects[GC_n_heap_sects-1]);
685: start = last_heap_sect -> hs_start;
686: if (p < start) return FALSE;
687: end = start + last_heap_sect -> hs_bytes;
688: if (p >= end) return FALSE;
689: return TRUE;
690: }
691: #endif
692:
693: # if !defined(NO_DEBUGGING)
694: void GC_print_heap_sects()
695: {
696: register unsigned i;
697:
698: GC_printf1("Total heap size: %lu\n", (unsigned long) GC_heapsize);
699: for (i = 0; i < GC_n_heap_sects; i++) {
700: unsigned long start = (unsigned long) GC_heap_sects[i].hs_start;
701: unsigned long len = (unsigned long) GC_heap_sects[i].hs_bytes;
702: struct hblk *h;
703: unsigned nbl = 0;
704:
705: GC_printf3("Section %ld from 0x%lx to 0x%lx ", (unsigned long)i,
706: start, (unsigned long)(start + len));
707: for (h = (struct hblk *)start; h < (struct hblk *)(start + len); h++) {
708: if (GC_is_black_listed(h, HBLKSIZE)) nbl++;
709: }
710: GC_printf2("%lu/%lu blacklisted\n", (unsigned long)nbl,
711: (unsigned long)(len/HBLKSIZE));
712: }
713: }
714: # endif
715:
716: ptr_t GC_least_plausible_heap_addr = (ptr_t)ONES;
717: ptr_t GC_greatest_plausible_heap_addr = 0;
718:
719: ptr_t GC_max(x,y)
720: ptr_t x, y;
721: {
722: return(x > y? x : y);
723: }
724:
725: ptr_t GC_min(x,y)
726: ptr_t x, y;
727: {
728: return(x < y? x : y);
729: }
730:
731: # if defined(__STDC__) || defined(__cplusplus)
732: void GC_set_max_heap_size(GC_word n)
733: # else
734: void GC_set_max_heap_size(n)
735: GC_word n;
736: # endif
737: {
738: GC_max_heapsize = n;
739: }
740:
741: GC_word GC_max_retries = 0;
742:
743: /*
744: * this explicitly increases the size of the heap. It is used
745: * internally, but may also be invoked from GC_expand_hp by the user.
746: * The argument is in units of HBLKSIZE.
747: * Tiny values of n are rounded up.
748: * Returns FALSE on failure.
749: */
750: GC_bool GC_expand_hp_inner(n)
751: word n;
752: {
753: word bytes;
754: struct hblk * space;
755: word expansion_slop; /* Number of bytes by which we expect the */
756: /* heap to expand soon. */
757:
758: if (n < MINHINCR) n = MINHINCR;
759: bytes = n * HBLKSIZE;
760: /* Make sure bytes is a multiple of GC_page_size */
761: {
762: word mask = GC_page_size - 1;
763: bytes += mask;
764: bytes &= ~mask;
765: }
766:
767: if (GC_max_heapsize != 0 && GC_heapsize + bytes > GC_max_heapsize) {
768: /* Exceeded self-imposed limit */
769: return(FALSE);
770: }
771: space = GET_MEM(bytes);
772: if( space == 0 ) {
773: return(FALSE);
774: }
775: # ifdef PRINTSTATS
776: GC_printf2("Increasing heap size by %lu after %lu allocated bytes\n",
777: (unsigned long)bytes,
778: (unsigned long)WORDS_TO_BYTES(GC_words_allocd));
779: # ifdef UNDEFINED
780: GC_printf1("Root size = %lu\n", GC_root_size);
781: GC_print_block_list(); GC_print_hblkfreelist();
782: GC_printf0("\n");
783: # endif
784: # endif
785: expansion_slop = 8 * WORDS_TO_BYTES(min_words_allocd());
786: if (5 * HBLKSIZE * MAXHINCR > expansion_slop) {
787: expansion_slop = 5 * HBLKSIZE * MAXHINCR;
788: }
789: if (GC_last_heap_addr == 0 && !((word)space & SIGNB)
790: || GC_last_heap_addr != 0 && GC_last_heap_addr < (ptr_t)space) {
791: /* Assume the heap is growing up */
792: GC_greatest_plausible_heap_addr =
793: GC_max(GC_greatest_plausible_heap_addr,
794: (ptr_t)space + bytes + expansion_slop);
795: } else {
796: /* Heap is growing down */
797: GC_least_plausible_heap_addr =
798: GC_min(GC_least_plausible_heap_addr,
799: (ptr_t)space - expansion_slop);
800: }
801: GC_prev_heap_addr = GC_last_heap_addr;
802: GC_last_heap_addr = (ptr_t)space;
803: GC_add_to_heap(space, bytes);
804: #if defined(VISUAL_LIB)
805: SendHeapSize();
806: #endif
807: return(TRUE);
808: }
809:
810: /* Really returns a bool, but it's externally visible, so that's clumsy. */
811: /* Arguments is in bytes. */
812: # if defined(__STDC__) || defined(__cplusplus)
813: int GC_expand_hp(size_t bytes)
814: # else
815: int GC_expand_hp(bytes)
816: size_t bytes;
817: # endif
818: {
819: int result;
820: DCL_LOCK_STATE;
821:
822: DISABLE_SIGNALS();
823: LOCK();
824: if (!GC_is_initialized) GC_init_inner();
825: result = (int)GC_expand_hp_inner(divHBLKSZ((word)bytes));
826: # ifdef PRESERVE_LAST
827: if (result) GC_protect_last_block = FALSE;
828: # endif
829: UNLOCK();
830: ENABLE_SIGNALS();
831: return(result);
832: }
833:
834: unsigned GC_fail_count = 0;
835: /* How many consecutive GC/expansion failures? */
836: /* Reset by GC_allochblk. */
837:
838: GC_bool GC_collect_or_expand(needed_blocks, ignore_off_page)
839: word needed_blocks;
840: GC_bool ignore_off_page;
841: {
842: if (!GC_incremental && !GC_dont_gc && GC_should_collect()) {
843: GC_notify_full_gc();
844: GC_gcollect_inner();
845: } else {
846: word blocks_to_get = (GC_heapsize*GC_free_space_numerator)/(HBLKSIZE*GC_free_space_divisor)
847: + needed_blocks;
848:
849: if (blocks_to_get > MAXHINCR) {
850: word slop;
851:
852: if (ignore_off_page) {
853: slop = 4;
854: } else {
855: slop = 2*divHBLKSZ(BL_LIMIT);
856: if (slop > needed_blocks) slop = needed_blocks;
857: }
858: if (needed_blocks + slop > MAXHINCR) {
859: blocks_to_get = needed_blocks + slop;
860: } else {
861: blocks_to_get = MAXHINCR;
862: }
863: }
864: if (!GC_expand_hp_inner(blocks_to_get)
865: && !GC_expand_hp_inner(needed_blocks)) {
866: if (GC_fail_count++ < GC_max_retries) {
867: WARN("Out of Memory! Trying to continue ...\n", 0);
868: GC_notify_full_gc();
869: GC_gcollect_inner();
870: } else {
871: WARN("Out of Memory! Returning NIL!\n", 0);
872: return(FALSE);
873: }
874: } else {
875: # ifdef PRINTSTATS
876: if (GC_fail_count) {
877: GC_printf0("Memory available again ...\n");
878: }
879: # endif
880: # ifdef PRESERVE_LAST
881: if (needed_blocks > 1) GC_protect_last_block = TRUE;
882: /* We were forced to expand the heap as the result */
883: /* of a large block allocation. Avoid breaking up */
884: /* new block into small pieces. */
885: # endif
886: }
887: }
888: return(TRUE);
889: }
890:
891: /*
892: * Make sure the object free list for sz is not empty.
893: * Return a pointer to the first object on the free list.
894: * The object MUST BE REMOVED FROM THE FREE LIST BY THE CALLER.
895: * Assumes we hold the allocator lock and signals are disabled.
896: *
897: */
898: ptr_t GC_allocobj(sz, kind)
899: word sz;
900: int kind;
901: {
902: register ptr_t * flh = &(GC_obj_kinds[kind].ok_freelist[sz]);
903:
904: if (sz == 0) return(0);
905:
906: #if defined(VISUAL)
907: {
908: #include <signal.h>
909: extern int recv_intr;
910: if ( recv_intr ) {
911: if ( recv_intr == 1 ) {
912: recv_intr = 0;
913: int_handler();
914: } else {
915: recv_intr = 0;
916: ox_usr1_handler(0);
917: }
918: }
919: }
920: #endif
921: while (*flh == 0) {
922: ENTER_GC();
923: /* Do our share of marking work */
924: if(GC_incremental && !GC_dont_gc) GC_collect_a_little_inner(1);
925: /* Sweep blocks for objects of this size */
926: GC_continue_reclaim(sz, kind);
927: EXIT_GC();
928: if (*flh == 0) {
929: GC_new_hblk(sz, kind);
930: }
931: if (*flh == 0) {
932: ENTER_GC();
933: if (!GC_collect_or_expand((word)1,FALSE)) {
934: EXIT_GC();
935: return(0);
936: }
937: EXIT_GC();
938: }
939: }
940:
941: return(*flh);
942: }
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