Line data Source code
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) 1998-1999 by Silicon Graphics. All rights reserved.
5 : * Copyright (c) 1999 by Hewlett-Packard Company. All rights reserved.
6 : *
7 : * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
8 : * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
9 : *
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.
15 : */
16 :
17 : #include "private/gc_priv.h"
18 :
19 : #include <stdio.h>
20 :
21 : #ifdef GC_USE_ENTIRE_HEAP
22 : int GC_use_entire_heap = TRUE;
23 : #else
24 : int GC_use_entire_heap = FALSE;
25 : #endif
26 :
27 : /*
28 : * Free heap blocks are kept on one of several free lists,
29 : * depending on the size of the block. Each free list is doubly linked.
30 : * Adjacent free blocks are coalesced.
31 : */
32 :
33 :
34 : # define MAX_BLACK_LIST_ALLOC (2*HBLKSIZE)
35 : /* largest block we will allocate starting on a black */
36 : /* listed block. Must be >= HBLKSIZE. */
37 :
38 :
39 : # define UNIQUE_THRESHOLD 32
40 : /* Sizes up to this many HBLKs each have their own free list */
41 : # define HUGE_THRESHOLD 256
42 : /* Sizes of at least this many heap blocks are mapped to a */
43 : /* single free list. */
44 : # define FL_COMPRESSION 8
45 : /* In between sizes map this many distinct sizes to a single */
46 : /* bin. */
47 :
48 : # define N_HBLK_FLS ((HUGE_THRESHOLD - UNIQUE_THRESHOLD) / FL_COMPRESSION \
49 : + UNIQUE_THRESHOLD)
50 :
51 : #ifndef GC_GCJ_SUPPORT
52 : STATIC
53 : #endif
54 : struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 };
55 : /* List of completely empty heap blocks */
56 : /* Linked through hb_next field of */
57 : /* header structure associated with */
58 : /* block. Remains externally visible */
59 : /* as used by GNU GCJ currently. */
60 :
61 : #ifndef GC_GCJ_SUPPORT
62 : STATIC
63 : #endif
64 : word GC_free_bytes[N_HBLK_FLS+1] = { 0 };
65 : /* Number of free bytes on each list. Remains visible to GCJ. */
66 :
67 : /* Return the largest n such that the number of free bytes on lists */
68 : /* n .. N_HBLK_FLS is greater or equal to GC_max_large_allocd_bytes */
69 : /* minus GC_large_allocd_bytes. If there is no such n, return 0. */
70 5041 : GC_INLINE int GC_enough_large_bytes_left(void)
71 : {
72 : int n;
73 5041 : word bytes = GC_large_allocd_bytes;
74 :
75 : GC_ASSERT(GC_max_large_allocd_bytes <= GC_heapsize);
76 25854 : for (n = N_HBLK_FLS; n >= 0; --n) {
77 25792 : bytes += GC_free_bytes[n];
78 25792 : if (bytes >= GC_max_large_allocd_bytes) return n;
79 : }
80 62 : return 0;
81 : }
82 :
83 : /* Map a number of blocks to the appropriate large block free list index. */
84 165070 : STATIC int GC_hblk_fl_from_blocks(word blocks_needed)
85 : {
86 165070 : if (blocks_needed <= UNIQUE_THRESHOLD) return (int)blocks_needed;
87 73419 : if (blocks_needed >= HUGE_THRESHOLD) return N_HBLK_FLS;
88 23026 : return (int)(blocks_needed - UNIQUE_THRESHOLD)/FL_COMPRESSION
89 23026 : + UNIQUE_THRESHOLD;
90 :
91 : }
92 :
93 : # define PHDR(hhdr) HDR((hhdr) -> hb_prev)
94 : # define NHDR(hhdr) HDR((hhdr) -> hb_next)
95 :
96 : # ifdef USE_MUNMAP
97 : # define IS_MAPPED(hhdr) (((hhdr) -> hb_flags & WAS_UNMAPPED) == 0)
98 : # else
99 : # define IS_MAPPED(hhdr) TRUE
100 : # endif /* !USE_MUNMAP */
101 :
102 : #if !defined(NO_DEBUGGING) || defined(GC_ASSERTIONS)
103 : /* Should return the same value as GC_large_free_bytes. */
104 0 : GC_INNER word GC_compute_large_free_bytes(void)
105 : {
106 : struct hblk * h;
107 : hdr * hhdr;
108 0 : word total_free = 0;
109 : unsigned i;
110 :
111 0 : for (i = 0; i <= N_HBLK_FLS; ++i) {
112 0 : for (h = GC_hblkfreelist[i]; h != 0; h = hhdr->hb_next) {
113 0 : hhdr = HDR(h);
114 0 : total_free += hhdr->hb_sz;
115 : }
116 : }
117 0 : return total_free;
118 : }
119 : #endif /* !NO_DEBUGGING || GC_ASSERTIONS */
120 :
121 : # if !defined(NO_DEBUGGING)
122 0 : void GC_print_hblkfreelist(void)
123 : {
124 : struct hblk * h;
125 : hdr * hhdr;
126 : unsigned i;
127 : word total;
128 :
129 0 : for (i = 0; i <= N_HBLK_FLS; ++i) {
130 0 : h = GC_hblkfreelist[i];
131 0 : if (0 != h) GC_printf("Free list %u (total size %lu):\n",
132 : i, (unsigned long)GC_free_bytes[i]);
133 0 : while (h != 0) {
134 0 : hhdr = HDR(h);
135 0 : GC_printf("\t%p size %lu %s black listed\n",
136 : (void *)h, (unsigned long) hhdr -> hb_sz,
137 : GC_is_black_listed(h, HBLKSIZE) != 0 ? "start" :
138 0 : GC_is_black_listed(h, hhdr -> hb_sz) != 0 ? "partially" :
139 : "not");
140 0 : h = hhdr -> hb_next;
141 : }
142 : }
143 0 : GC_printf("GC_large_free_bytes: %lu\n",
144 : (unsigned long)GC_large_free_bytes);
145 :
146 0 : if ((total = GC_compute_large_free_bytes()) != GC_large_free_bytes)
147 0 : GC_err_printf("GC_large_free_bytes INCONSISTENT!! Should be: %lu\n",
148 : (unsigned long)total);
149 0 : }
150 :
151 : /* Return the free list index on which the block described by the header */
152 : /* appears, or -1 if it appears nowhere. */
153 0 : static int free_list_index_of(hdr *wanted)
154 : {
155 : struct hblk * h;
156 : hdr * hhdr;
157 : int i;
158 :
159 0 : for (i = 0; i <= N_HBLK_FLS; ++i) {
160 0 : h = GC_hblkfreelist[i];
161 0 : while (h != 0) {
162 0 : hhdr = HDR(h);
163 0 : if (hhdr == wanted) return i;
164 0 : h = hhdr -> hb_next;
165 : }
166 : }
167 0 : return -1;
168 : }
169 :
170 0 : void GC_dump_regions(void)
171 : {
172 : unsigned i;
173 : ptr_t start, end;
174 : ptr_t p;
175 : size_t bytes;
176 : hdr *hhdr;
177 0 : for (i = 0; i < GC_n_heap_sects; ++i) {
178 0 : start = GC_heap_sects[i].hs_start;
179 0 : bytes = GC_heap_sects[i].hs_bytes;
180 0 : end = start + bytes;
181 : /* Merge in contiguous sections. */
182 0 : while (i+1 < GC_n_heap_sects && GC_heap_sects[i+1].hs_start == end) {
183 0 : ++i;
184 0 : end = GC_heap_sects[i].hs_start + GC_heap_sects[i].hs_bytes;
185 : }
186 0 : GC_printf("***Section from %p to %p\n", start, end);
187 0 : for (p = start; (word)p < (word)end; ) {
188 0 : hhdr = HDR(p);
189 0 : if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
190 0 : GC_printf("\t%p Missing header!!(%p)\n", p, (void *)hhdr);
191 0 : p += HBLKSIZE;
192 0 : continue;
193 : }
194 0 : if (HBLK_IS_FREE(hhdr)) {
195 0 : int correct_index = GC_hblk_fl_from_blocks(
196 0 : divHBLKSZ(hhdr -> hb_sz));
197 : int actual_index;
198 :
199 0 : GC_printf("\t%p\tfree block of size 0x%lx bytes%s\n", p,
200 : (unsigned long)(hhdr -> hb_sz),
201 : IS_MAPPED(hhdr) ? "" : " (unmapped)");
202 0 : actual_index = free_list_index_of(hhdr);
203 0 : if (-1 == actual_index) {
204 0 : GC_printf("\t\tBlock not on free list %d!!\n",
205 : correct_index);
206 0 : } else if (correct_index != actual_index) {
207 0 : GC_printf("\t\tBlock on list %d, should be on %d!!\n",
208 : actual_index, correct_index);
209 : }
210 0 : p += hhdr -> hb_sz;
211 : } else {
212 0 : GC_printf("\t%p\tused for blocks of size 0x%lx bytes\n", p,
213 : (unsigned long)(hhdr -> hb_sz));
214 0 : p += HBLKSIZE * OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
215 : }
216 : }
217 : }
218 0 : }
219 :
220 : # endif /* NO_DEBUGGING */
221 :
222 : /* Initialize hdr for a block containing the indicated size and */
223 : /* kind of objects. */
224 : /* Return FALSE on failure. */
225 53040 : static GC_bool setup_header(hdr * hhdr, struct hblk *block, size_t byte_sz,
226 : int kind, unsigned flags)
227 : {
228 : word descr;
229 : # ifndef MARK_BIT_PER_OBJ
230 : size_t granules;
231 : # endif
232 :
233 : # ifdef ENABLE_DISCLAIM
234 53040 : if (GC_obj_kinds[kind].ok_disclaim_proc)
235 0 : flags |= HAS_DISCLAIM;
236 53040 : if (GC_obj_kinds[kind].ok_mark_unconditionally)
237 0 : flags |= MARK_UNCONDITIONALLY;
238 : # endif
239 :
240 : /* Set size, kind and mark proc fields */
241 53040 : hhdr -> hb_sz = byte_sz;
242 53040 : hhdr -> hb_obj_kind = (unsigned char)kind;
243 53040 : hhdr -> hb_flags = (unsigned char)flags;
244 53040 : hhdr -> hb_block = block;
245 53040 : descr = GC_obj_kinds[kind].ok_descriptor;
246 53040 : if (GC_obj_kinds[kind].ok_relocate_descr) descr += byte_sz;
247 53040 : hhdr -> hb_descr = descr;
248 :
249 : # ifdef MARK_BIT_PER_OBJ
250 : /* Set hb_inv_sz as portably as possible. */
251 : /* We set it to the smallest value such that sz * inv_sz > 2**32 */
252 : /* This may be more precision than necessary. */
253 : if (byte_sz > MAXOBJBYTES) {
254 : hhdr -> hb_inv_sz = LARGE_INV_SZ;
255 : } else {
256 : word inv_sz;
257 :
258 : # if CPP_WORDSZ == 64
259 : inv_sz = ((word)1 << 32)/byte_sz;
260 : if (((inv_sz*byte_sz) >> 32) == 0) ++inv_sz;
261 : # else /* 32 bit words */
262 : GC_ASSERT(byte_sz >= 4);
263 : inv_sz = ((unsigned)1 << 31)/byte_sz;
264 : inv_sz *= 2;
265 : while (inv_sz*byte_sz > byte_sz) ++inv_sz;
266 : # endif
267 : hhdr -> hb_inv_sz = inv_sz;
268 : }
269 : # else /* MARK_BIT_PER_GRANULE */
270 53040 : hhdr -> hb_large_block = (unsigned char)(byte_sz > MAXOBJBYTES);
271 53040 : granules = BYTES_TO_GRANULES(byte_sz);
272 53040 : if (EXPECT(!GC_add_map_entry(granules), FALSE)) {
273 : /* Make it look like a valid block. */
274 0 : hhdr -> hb_sz = HBLKSIZE;
275 0 : hhdr -> hb_descr = 0;
276 0 : hhdr -> hb_large_block = TRUE;
277 0 : hhdr -> hb_map = 0;
278 0 : return FALSE;
279 : } else {
280 53040 : size_t index = (hhdr -> hb_large_block? 0 : granules);
281 53040 : hhdr -> hb_map = GC_obj_map[index];
282 : }
283 : # endif /* MARK_BIT_PER_GRANULE */
284 :
285 : /* Clear mark bits */
286 53040 : GC_clear_hdr_marks(hhdr);
287 :
288 53040 : hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
289 53040 : return(TRUE);
290 : }
291 :
292 : /* Remove hhdr from the free list (it is assumed to specified by index). */
293 82183 : STATIC void GC_remove_from_fl_at(hdr *hhdr, int index)
294 : {
295 : GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
296 82183 : if (hhdr -> hb_prev == 0) {
297 : GC_ASSERT(HDR(GC_hblkfreelist[index]) == hhdr);
298 82128 : GC_hblkfreelist[index] = hhdr -> hb_next;
299 : } else {
300 : hdr *phdr;
301 55 : GET_HDR(hhdr -> hb_prev, phdr);
302 55 : phdr -> hb_next = hhdr -> hb_next;
303 : }
304 : /* We always need index to maintain free counts. */
305 : GC_ASSERT(GC_free_bytes[index] >= hhdr -> hb_sz);
306 82183 : GC_free_bytes[index] -= hhdr -> hb_sz;
307 82183 : if (0 != hhdr -> hb_next) {
308 : hdr * nhdr;
309 : GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr)));
310 19989 : GET_HDR(hhdr -> hb_next, nhdr);
311 19989 : nhdr -> hb_prev = hhdr -> hb_prev;
312 : }
313 82183 : }
314 :
315 : /* Remove hhdr from the appropriate free list (we assume it is on the */
316 : /* size-appropriate free list). */
317 29143 : GC_INLINE void GC_remove_from_fl(hdr *hhdr)
318 : {
319 29143 : GC_remove_from_fl_at(hhdr, GC_hblk_fl_from_blocks(divHBLKSZ(hhdr->hb_sz)));
320 29143 : }
321 :
322 : /* Return a pointer to the free block ending just before h, if any. */
323 32964 : STATIC struct hblk * GC_free_block_ending_at(struct hblk *h)
324 : {
325 32964 : struct hblk * p = h - 1;
326 : hdr * phdr;
327 :
328 32964 : GET_HDR(p, phdr);
329 66470 : while (0 != phdr && IS_FORWARDING_ADDR_OR_NIL(phdr)) {
330 542 : p = FORWARDED_ADDR(p,phdr);
331 542 : phdr = HDR(p);
332 : }
333 32964 : if (0 != phdr) {
334 32473 : if(HBLK_IS_FREE(phdr)) {
335 1 : return p;
336 : } else {
337 32472 : return 0;
338 : }
339 : }
340 491 : p = GC_prev_block(h - 1);
341 491 : if (0 != p) {
342 316 : phdr = HDR(p);
343 316 : if (HBLK_IS_FREE(phdr) && (ptr_t)p + phdr -> hb_sz == (ptr_t)h) {
344 243 : return p;
345 : }
346 : }
347 248 : return 0;
348 : }
349 :
350 : /* Add hhdr to the appropriate free list. */
351 : /* We maintain individual free lists sorted by address. */
352 82729 : STATIC void GC_add_to_fl(struct hblk *h, hdr *hhdr)
353 : {
354 82729 : int index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
355 82729 : struct hblk *second = GC_hblkfreelist[index];
356 : hdr * second_hdr;
357 : # if defined(GC_ASSERTIONS) && !defined(USE_MUNMAP)
358 : struct hblk *next = (struct hblk *)((word)h + hhdr -> hb_sz);
359 : hdr * nexthdr = HDR(next);
360 : struct hblk *prev = GC_free_block_ending_at(h);
361 : hdr * prevhdr = HDR(prev);
362 : GC_ASSERT(nexthdr == 0 || !HBLK_IS_FREE(nexthdr)
363 : || (signed_word)GC_heapsize < 0);
364 : /* In the last case, blocks may be too large to merge. */
365 : GC_ASSERT(prev == 0 || !HBLK_IS_FREE(prevhdr)
366 : || (signed_word)GC_heapsize < 0);
367 : # endif
368 :
369 : GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
370 82729 : GC_hblkfreelist[index] = h;
371 82729 : GC_free_bytes[index] += hhdr -> hb_sz;
372 : GC_ASSERT(GC_free_bytes[index] <= GC_large_free_bytes);
373 82729 : hhdr -> hb_next = second;
374 82729 : hhdr -> hb_prev = 0;
375 82729 : if (0 != second) {
376 20365 : GET_HDR(second, second_hdr);
377 20365 : second_hdr -> hb_prev = h;
378 : }
379 82729 : hhdr -> hb_flags |= FREE_BLK;
380 82729 : }
381 :
382 : #ifdef USE_MUNMAP
383 :
384 : # ifndef MUNMAP_THRESHOLD
385 : # define MUNMAP_THRESHOLD 6
386 : # endif
387 :
388 : GC_INNER int GC_unmap_threshold = MUNMAP_THRESHOLD;
389 :
390 : /* Unmap blocks that haven't been recently touched. This is the only way */
391 : /* way blocks are ever unmapped. */
392 : GC_INNER void GC_unmap_old(void)
393 : {
394 : struct hblk * h;
395 : hdr * hhdr;
396 : int i;
397 :
398 : if (GC_unmap_threshold == 0)
399 : return; /* unmapping disabled */
400 :
401 : for (i = 0; i <= N_HBLK_FLS; ++i) {
402 : for (h = GC_hblkfreelist[i]; 0 != h; h = hhdr -> hb_next) {
403 : hhdr = HDR(h);
404 : if (!IS_MAPPED(hhdr)) continue;
405 :
406 : if ((unsigned short)GC_gc_no - hhdr -> hb_last_reclaimed >
407 : (unsigned short)GC_unmap_threshold) {
408 : GC_unmap((ptr_t)h, hhdr -> hb_sz);
409 : hhdr -> hb_flags |= WAS_UNMAPPED;
410 : }
411 : }
412 : }
413 : }
414 :
415 : /* Merge all unmapped blocks that are adjacent to other free */
416 : /* blocks. This may involve remapping, since all blocks are either */
417 : /* fully mapped or fully unmapped. */
418 : GC_INNER void GC_merge_unmapped(void)
419 : {
420 : struct hblk * h, *next;
421 : hdr * hhdr, *nexthdr;
422 : word size, nextsize;
423 : int i;
424 :
425 : for (i = 0; i <= N_HBLK_FLS; ++i) {
426 : h = GC_hblkfreelist[i];
427 : while (h != 0) {
428 : GET_HDR(h, hhdr);
429 : size = hhdr->hb_sz;
430 : next = (struct hblk *)((word)h + size);
431 : GET_HDR(next, nexthdr);
432 : /* Coalesce with successor, if possible */
433 : if (0 != nexthdr && HBLK_IS_FREE(nexthdr)
434 : && (signed_word) (size + (nextsize = nexthdr->hb_sz)) > 0
435 : /* no pot. overflow */) {
436 : /* Note that we usually try to avoid adjacent free blocks */
437 : /* that are either both mapped or both unmapped. But that */
438 : /* isn't guaranteed to hold since we remap blocks when we */
439 : /* split them, and don't merge at that point. It may also */
440 : /* not hold if the merged block would be too big. */
441 : if (IS_MAPPED(hhdr) && !IS_MAPPED(nexthdr)) {
442 : /* make both consistent, so that we can merge */
443 : if (size > nextsize) {
444 : GC_remap((ptr_t)next, nextsize);
445 : } else {
446 : GC_unmap((ptr_t)h, size);
447 : GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
448 : hhdr -> hb_flags |= WAS_UNMAPPED;
449 : }
450 : } else if (IS_MAPPED(nexthdr) && !IS_MAPPED(hhdr)) {
451 : if (size > nextsize) {
452 : GC_unmap((ptr_t)next, nextsize);
453 : GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
454 : } else {
455 : GC_remap((ptr_t)h, size);
456 : hhdr -> hb_flags &= ~WAS_UNMAPPED;
457 : hhdr -> hb_last_reclaimed = nexthdr -> hb_last_reclaimed;
458 : }
459 : } else if (!IS_MAPPED(hhdr) && !IS_MAPPED(nexthdr)) {
460 : /* Unmap any gap in the middle */
461 : GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nextsize);
462 : }
463 : /* If they are both unmapped, we merge, but leave unmapped. */
464 : GC_remove_from_fl_at(hhdr, i);
465 : GC_remove_from_fl(nexthdr);
466 : hhdr -> hb_sz += nexthdr -> hb_sz;
467 : GC_remove_header(next);
468 : GC_add_to_fl(h, hhdr);
469 : /* Start over at beginning of list */
470 : h = GC_hblkfreelist[i];
471 : } else /* not mergable with successor */ {
472 : h = hhdr -> hb_next;
473 : }
474 : } /* while (h != 0) ... */
475 : } /* for ... */
476 : }
477 :
478 : #endif /* USE_MUNMAP */
479 :
480 : /*
481 : * Return a pointer to a block starting at h of length bytes.
482 : * Memory for the block is mapped.
483 : * Remove the block from its free list, and return the remainder (if any)
484 : * to its appropriate free list.
485 : * May fail by returning 0.
486 : * The header for the returned block must be set up by the caller.
487 : * If the return value is not 0, then hhdr is the header for it.
488 : */
489 53038 : STATIC struct hblk * GC_get_first_part(struct hblk *h, hdr *hhdr,
490 : size_t bytes, int index)
491 : {
492 53038 : word total_size = hhdr -> hb_sz;
493 : struct hblk * rest;
494 : hdr * rest_hdr;
495 :
496 : GC_ASSERT((total_size & (HBLKSIZE-1)) == 0);
497 53038 : GC_remove_from_fl_at(hhdr, index);
498 53038 : if (total_size == bytes) return h;
499 49750 : rest = (struct hblk *)((word)h + bytes);
500 49750 : rest_hdr = GC_install_header(rest);
501 49750 : if (0 == rest_hdr) {
502 : /* FIXME: This is likely to be very bad news ... */
503 0 : WARN("Header allocation failed: Dropping block.\n", 0);
504 0 : return(0);
505 : }
506 49750 : rest_hdr -> hb_sz = total_size - bytes;
507 49750 : rest_hdr -> hb_flags = 0;
508 : # ifdef GC_ASSERTIONS
509 : /* Mark h not free, to avoid assertion about adjacent free blocks. */
510 : hhdr -> hb_flags &= ~FREE_BLK;
511 : # endif
512 49750 : GC_add_to_fl(rest, rest_hdr);
513 49750 : return h;
514 : }
515 :
516 : /*
517 : * H is a free block. N points at an address inside it.
518 : * A new header for n has already been set up. Fix up h's header
519 : * to reflect the fact that it is being split, move it to the
520 : * appropriate free list.
521 : * N replaces h in the original free list.
522 : *
523 : * Nhdr is not completely filled in, since it is about to allocated.
524 : * It may in fact end up on the wrong free list for its size.
525 : * That's not a disaster, since n is about to be allocated
526 : * by our caller.
527 : * (Hence adding it to a free list is silly. But this path is hopefully
528 : * rare enough that it doesn't matter. The code is cleaner this way.)
529 : */
530 15 : STATIC void GC_split_block(struct hblk *h, hdr *hhdr, struct hblk *n,
531 : hdr *nhdr, int index /* Index of free list */)
532 : {
533 15 : word total_size = hhdr -> hb_sz;
534 15 : word h_size = (word)n - (word)h;
535 15 : struct hblk *prev = hhdr -> hb_prev;
536 15 : struct hblk *next = hhdr -> hb_next;
537 :
538 : /* Replace h with n on its freelist */
539 15 : nhdr -> hb_prev = prev;
540 15 : nhdr -> hb_next = next;
541 15 : nhdr -> hb_sz = total_size - h_size;
542 15 : nhdr -> hb_flags = 0;
543 15 : if (0 != prev) {
544 0 : HDR(prev) -> hb_next = n;
545 : } else {
546 15 : GC_hblkfreelist[index] = n;
547 : }
548 15 : if (0 != next) {
549 0 : HDR(next) -> hb_prev = n;
550 : }
551 : GC_ASSERT(GC_free_bytes[index] > h_size);
552 15 : GC_free_bytes[index] -= h_size;
553 : # ifdef USE_MUNMAP
554 : hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
555 : # endif
556 15 : hhdr -> hb_sz = h_size;
557 15 : GC_add_to_fl(h, hhdr);
558 15 : nhdr -> hb_flags |= FREE_BLK;
559 15 : }
560 :
561 : STATIC struct hblk *
562 : GC_allochblk_nth(size_t sz /* bytes */, int kind, unsigned flags, int n,
563 : int may_split);
564 : #define AVOID_SPLIT_REMAPPED 2
565 :
566 : /*
567 : * Allocate (and return pointer to) a heap block
568 : * for objects of size sz bytes, searching the nth free list.
569 : *
570 : * NOTE: We set obj_map field in header correctly.
571 : * Caller is responsible for building an object freelist in block.
572 : *
573 : * The client is responsible for clearing the block, if necessary.
574 : */
575 : GC_INNER struct hblk *
576 53198 : GC_allochblk(size_t sz, int kind, unsigned flags/* IGNORE_OFF_PAGE or 0 */)
577 : {
578 : word blocks;
579 : int start_list;
580 : struct hblk *result;
581 : int may_split;
582 : int split_limit; /* Highest index of free list whose blocks we */
583 : /* split. */
584 :
585 : GC_ASSERT((sz & (GRANULE_BYTES - 1)) == 0);
586 53198 : blocks = OBJ_SZ_TO_BLOCKS(sz);
587 53198 : if ((signed_word)(blocks * HBLKSIZE) < 0) {
588 0 : return 0;
589 : }
590 53198 : start_list = GC_hblk_fl_from_blocks(blocks);
591 : /* Try for an exact match first. */
592 53198 : result = GC_allochblk_nth(sz, kind, flags, start_list, FALSE);
593 53198 : if (0 != result) return result;
594 :
595 49910 : may_split = TRUE;
596 244867 : if (GC_use_entire_heap || GC_dont_gc
597 99820 : || USED_HEAP_SIZE < GC_requested_heapsize
598 100178 : || GC_incremental || !GC_should_collect()) {
599 : /* Should use more of the heap, even if it requires splitting. */
600 44869 : split_limit = N_HBLK_FLS;
601 5041 : } else if (GC_finalizer_bytes_freed > (GC_heapsize >> 4)) {
602 : /* If we are deallocating lots of memory from */
603 : /* finalizers, fail and collect sooner rather */
604 : /* than later. */
605 0 : split_limit = 0;
606 : } else {
607 : /* If we have enough large blocks left to cover any */
608 : /* previous request for large blocks, we go ahead */
609 : /* and split. Assuming a steady state, that should */
610 : /* be safe. It means that we can use the full */
611 : /* heap if we allocate only small objects. */
612 5041 : split_limit = GC_enough_large_bytes_left();
613 : # ifdef USE_MUNMAP
614 : if (split_limit > 0)
615 : may_split = AVOID_SPLIT_REMAPPED;
616 : # endif
617 : }
618 49910 : if (start_list < UNIQUE_THRESHOLD) {
619 : /* No reason to try start_list again, since all blocks are exact */
620 : /* matches. */
621 49698 : ++start_list;
622 : }
623 2307737 : for (; start_list <= split_limit; ++start_list) {
624 2307577 : result = GC_allochblk_nth(sz, kind, flags, start_list, may_split);
625 2307577 : if (0 != result)
626 49750 : break;
627 : }
628 49910 : return result;
629 : }
630 :
631 : STATIC long GC_large_alloc_warn_suppressed = 0;
632 : /* Number of warnings suppressed so far. */
633 :
634 : /* The same, but with search restricted to nth free list. Flags is */
635 : /* IGNORE_OFF_PAGE or zero. sz is in bytes. The may_split flag */
636 : /* indicates whether it is OK to split larger blocks (if set to */
637 : /* AVOID_SPLIT_REMAPPED then memory remapping followed by splitting */
638 : /* should be generally avoided). */
639 : STATIC struct hblk *
640 2360777 : GC_allochblk_nth(size_t sz, int kind, unsigned flags, int n, int may_split)
641 : {
642 : struct hblk *hbp;
643 : hdr * hhdr; /* Header corr. to hbp */
644 : struct hblk *thishbp;
645 : hdr * thishdr; /* Header corr. to thishbp */
646 : signed_word size_needed; /* number of bytes in requested objects */
647 : signed_word size_avail; /* bytes available in this block */
648 :
649 2360777 : size_needed = HBLKSIZE * OBJ_SZ_TO_BLOCKS(sz);
650 :
651 : /* search for a big enough block in free list */
652 2360818 : for (hbp = GC_hblkfreelist[n];; hbp = hhdr -> hb_next) {
653 2360818 : if (NULL == hbp) return NULL;
654 53081 : GET_HDR(hbp, hhdr); /* set hhdr value */
655 53081 : size_avail = hhdr->hb_sz;
656 53081 : if (size_avail < size_needed) continue;
657 53066 : if (size_avail != size_needed) {
658 : signed_word next_size;
659 :
660 49753 : if (!may_split) continue;
661 : /* If the next heap block is obviously better, go on. */
662 : /* This prevents us from disassembling a single large */
663 : /* block to get tiny blocks. */
664 49752 : thishbp = hhdr -> hb_next;
665 49752 : if (thishbp != 0) {
666 1203 : GET_HDR(thishbp, thishdr);
667 1203 : next_size = (signed_word)(thishdr -> hb_sz);
668 1205 : if (next_size < size_avail
669 : && next_size >= size_needed
670 2 : && !GC_is_black_listed(thishbp, (word)size_needed)) {
671 2 : continue;
672 : }
673 : }
674 : }
675 53063 : if (!IS_UNCOLLECTABLE(kind) && (kind != PTRFREE
676 : || size_needed > (signed_word)MAX_BLACK_LIST_ALLOC)) {
677 34304 : struct hblk * lasthbp = hbp;
678 34304 : ptr_t search_end = (ptr_t)hbp + size_avail - size_needed;
679 34304 : signed_word orig_avail = size_avail;
680 34304 : signed_word eff_size_needed = (flags & IGNORE_OFF_PAGE) != 0 ?
681 : (signed_word)HBLKSIZE
682 34304 : : size_needed;
683 :
684 102970 : while ((word)lasthbp <= (word)search_end
685 68666 : && (thishbp = GC_is_black_listed(lasthbp,
686 : (word)eff_size_needed)) != 0) {
687 42 : lasthbp = thishbp;
688 : }
689 34304 : size_avail -= (ptr_t)lasthbp - (ptr_t)hbp;
690 34304 : thishbp = lasthbp;
691 34304 : if (size_avail >= size_needed) {
692 34278 : if (thishbp != hbp) {
693 : # ifdef USE_MUNMAP
694 : /* Avoid remapping followed by splitting. */
695 : if (may_split == AVOID_SPLIT_REMAPPED && !IS_MAPPED(hhdr))
696 : continue;
697 : # endif
698 15 : thishdr = GC_install_header(thishbp);
699 15 : if (0 != thishdr) {
700 : /* Make sure it's mapped before we mangle it. */
701 : # ifdef USE_MUNMAP
702 : if (!IS_MAPPED(hhdr)) {
703 : GC_remap((ptr_t)hbp, hhdr -> hb_sz);
704 : hhdr -> hb_flags &= ~WAS_UNMAPPED;
705 : }
706 : # endif
707 : /* Split the block at thishbp */
708 15 : GC_split_block(hbp, hhdr, thishbp, thishdr, n);
709 : /* Advance to thishbp */
710 15 : hbp = thishbp;
711 15 : hhdr = thishdr;
712 : /* We must now allocate thishbp, since it may */
713 : /* be on the wrong free list. */
714 : }
715 : }
716 28 : } else if (size_needed > (signed_word)BL_LIMIT
717 26 : && orig_avail - size_needed
718 1 : > (signed_word)BL_LIMIT) {
719 : /* Punt, since anything else risks unreasonable heap growth. */
720 1 : if (++GC_large_alloc_warn_suppressed
721 : >= GC_large_alloc_warn_interval) {
722 0 : WARN("Repeated allocation of very large block "
723 : "(appr. size %" WARN_PRIdPTR "):\n"
724 : "\tMay lead to memory leak and poor performance.\n",
725 : size_needed);
726 0 : GC_large_alloc_warn_suppressed = 0;
727 : }
728 1 : size_avail = orig_avail;
729 25 : } else if (size_avail == 0 && size_needed == HBLKSIZE
730 : && IS_MAPPED(hhdr)) {
731 24 : if (!GC_find_leak) {
732 : static unsigned count = 0;
733 :
734 : /* The block is completely blacklisted. We need */
735 : /* to drop some such blocks, since otherwise we spend */
736 : /* all our time traversing them if pointer-free */
737 : /* blocks are unpopular. */
738 : /* A dropped block will be reconsidered at next GC. */
739 24 : if ((++count & 3) == 0) {
740 : /* Allocate and drop the block in small chunks, to */
741 : /* maximize the chance that we will recover some */
742 : /* later. */
743 2 : word total_size = hhdr -> hb_sz;
744 2 : struct hblk * limit = hbp + divHBLKSZ(total_size);
745 : struct hblk * h;
746 2 : struct hblk * prev = hhdr -> hb_prev;
747 :
748 2 : GC_large_free_bytes -= total_size;
749 2 : GC_bytes_dropped += total_size;
750 2 : GC_remove_from_fl_at(hhdr, n);
751 4 : for (h = hbp; (word)h < (word)limit; h++) {
752 2 : if (h != hbp) {
753 0 : hhdr = GC_install_header(h);
754 : }
755 2 : if (NULL != hhdr) {
756 2 : (void)setup_header(hhdr, h, HBLKSIZE, PTRFREE, 0);
757 : /* Can't fail. */
758 2 : if (GC_debugging_started) {
759 0 : BZERO(h, HBLKSIZE);
760 : }
761 : }
762 : }
763 : /* Restore hbp to point at free block */
764 2 : hbp = prev;
765 2 : if (0 == hbp) {
766 2 : return GC_allochblk_nth(sz, kind, flags, n, may_split);
767 : }
768 0 : hhdr = HDR(hbp);
769 : }
770 : }
771 : }
772 : }
773 53061 : if( size_avail >= size_needed ) {
774 : # ifdef USE_MUNMAP
775 : if (!IS_MAPPED(hhdr)) {
776 : GC_remap((ptr_t)hbp, hhdr -> hb_sz);
777 : hhdr -> hb_flags &= ~WAS_UNMAPPED;
778 : /* Note: This may leave adjacent, mapped free blocks. */
779 : }
780 : # endif
781 : /* hbp may be on the wrong freelist; the parameter n */
782 : /* is important. */
783 53038 : hbp = GC_get_first_part(hbp, hhdr, size_needed, n);
784 : break;
785 : }
786 41 : }
787 :
788 53038 : if (0 == hbp) return 0;
789 :
790 : /* Add it to map of valid blocks */
791 53038 : if (!GC_install_counts(hbp, (word)size_needed)) return(0);
792 : /* This leaks memory under very rare conditions. */
793 :
794 : /* Set up header */
795 53038 : if (!setup_header(hhdr, hbp, sz, kind, flags)) {
796 0 : GC_remove_counts(hbp, (word)size_needed);
797 0 : return(0); /* ditto */
798 : }
799 : # ifndef GC_DISABLE_INCREMENTAL
800 : /* Notify virtual dirty bit implementation that we are about to */
801 : /* write. Ensure that pointer-free objects are not protected */
802 : /* if it is avoidable. This also ensures that newly allocated */
803 : /* blocks are treated as dirty. Necessary since we don't */
804 : /* protect free blocks. */
805 : GC_ASSERT((size_needed & (HBLKSIZE-1)) == 0);
806 53038 : GC_remove_protection(hbp, divHBLKSZ(size_needed),
807 : (hhdr -> hb_descr == 0) /* pointer-free */);
808 : # endif
809 : /* We just successfully allocated a block. Restart count of */
810 : /* consecutive failures. */
811 53038 : GC_fail_count = 0;
812 :
813 53038 : GC_large_free_bytes -= size_needed;
814 : GC_ASSERT(IS_MAPPED(hhdr));
815 53038 : return( hbp );
816 : }
817 :
818 : /*
819 : * Free a heap block.
820 : *
821 : * Coalesce the block with its neighbors if possible.
822 : *
823 : * All mark words are assumed to be cleared.
824 : */
825 32964 : GC_INNER void GC_freehblk(struct hblk *hbp)
826 : {
827 : struct hblk *next, *prev;
828 : hdr *hhdr, *prevhdr, *nexthdr;
829 : word size;
830 :
831 32964 : GET_HDR(hbp, hhdr);
832 32964 : size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(hhdr->hb_sz);
833 32964 : if ((signed_word)size <= 0)
834 0 : ABORT("Deallocating excessively large block. Too large an allocation?");
835 : /* Probably possible if we try to allocate more than half the address */
836 : /* space at once. If we don't catch it here, strange things happen */
837 : /* later. */
838 32964 : GC_remove_counts(hbp, size);
839 32964 : hhdr->hb_sz = size;
840 : # ifdef USE_MUNMAP
841 : hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
842 : # endif
843 :
844 : /* Check for duplicate deallocation in the easy case */
845 32964 : if (HBLK_IS_FREE(hhdr)) {
846 0 : ABORT_ARG1("Duplicate large block deallocation",
847 : " of %p", (void *)hbp);
848 : }
849 :
850 : GC_ASSERT(IS_MAPPED(hhdr));
851 32964 : hhdr -> hb_flags |= FREE_BLK;
852 32964 : next = (struct hblk *)((ptr_t)hbp + size);
853 32964 : GET_HDR(next, nexthdr);
854 32964 : prev = GC_free_block_ending_at(hbp);
855 : /* Coalesce with successor, if possible */
856 61863 : if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)
857 28899 : && (signed_word)(hhdr -> hb_sz + nexthdr -> hb_sz) > 0
858 : /* no overflow */) {
859 28899 : GC_remove_from_fl(nexthdr);
860 28899 : hhdr -> hb_sz += nexthdr -> hb_sz;
861 28899 : GC_remove_header(next);
862 : }
863 : /* Coalesce with predecessor, if possible. */
864 32964 : if (0 != prev) {
865 244 : prevhdr = HDR(prev);
866 244 : if (IS_MAPPED(prevhdr)
867 244 : && (signed_word)(hhdr -> hb_sz + prevhdr -> hb_sz) > 0) {
868 244 : GC_remove_from_fl(prevhdr);
869 244 : prevhdr -> hb_sz += hhdr -> hb_sz;
870 : # ifdef USE_MUNMAP
871 : prevhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
872 : # endif
873 244 : GC_remove_header(hbp);
874 244 : hbp = prev;
875 244 : hhdr = prevhdr;
876 : }
877 : }
878 : /* FIXME: It is not clear we really always want to do these merges */
879 : /* with USE_MUNMAP, since it updates ages and hence prevents */
880 : /* unmapping. */
881 :
882 32964 : GC_large_free_bytes += size;
883 32964 : GC_add_to_fl(hbp, hhdr);
884 32964 : }
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