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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [boehm-gc/] [allchblk.c] - Blame information for rev 721

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1 721 jeremybenn
/*
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
/* #define DEBUG */
18
#include <stdio.h>
19
#include "private/gc_priv.h"
20
 
21
GC_bool GC_use_entire_heap = 0;
22
 
23
/*
24
 * Free heap blocks are kept on one of several free lists,
25
 * depending on the size of the block.  Each free list is doubly linked.
26
 * Adjacent free blocks are coalesced.
27
 */
28
 
29
 
30
# define MAX_BLACK_LIST_ALLOC (2*HBLKSIZE)
31
                /* largest block we will allocate starting on a black   */
32
                /* listed block.  Must be >= HBLKSIZE.                  */
33
 
34
 
35
# define UNIQUE_THRESHOLD 32
36
        /* Sizes up to this many HBLKs each have their own free list    */
37
# define HUGE_THRESHOLD 256
38
        /* Sizes of at least this many heap blocks are mapped to a      */
39
        /* single free list.                                            */
40
# define FL_COMPRESSION 8
41
        /* In between sizes map this many distinct sizes to a single    */
42
        /* bin.                                                         */
43
 
44
# define N_HBLK_FLS (HUGE_THRESHOLD - UNIQUE_THRESHOLD)/FL_COMPRESSION \
45
                                 + UNIQUE_THRESHOLD
46
 
47
struct hblk * GC_hblkfreelist[N_HBLK_FLS+1] = { 0 };
48
 
49
#ifndef USE_MUNMAP
50
 
51
  word GC_free_bytes[N_HBLK_FLS+1] = { 0 };
52
        /* Number of free bytes on each list.   */
53
 
54
  /* Is bytes + the number of free bytes on lists n .. N_HBLK_FLS       */
55
  /* > GC_max_large_allocd_bytes?                                       */
56
# ifdef __GNUC__
57
  __inline__
58
# endif
59
  static GC_bool GC_enough_large_bytes_left(bytes,n)
60
  word bytes;
61
  int n;
62
  {
63
    int i;
64
    for (i = N_HBLK_FLS; i >= n; --i) {
65
        bytes += GC_free_bytes[i];
66
        if (bytes > GC_max_large_allocd_bytes) return TRUE;
67
    }
68
    return FALSE;
69
  }
70
 
71
# define INCR_FREE_BYTES(n, b) GC_free_bytes[n] += (b);
72
 
73
# define FREE_ASSERT(e) GC_ASSERT(e)
74
 
75
#else /* USE_MUNMAP */
76
 
77
# define INCR_FREE_BYTES(n, b)
78
# define FREE_ASSERT(e)
79
 
80
#endif /* USE_MUNMAP */
81
 
82
/* Map a number of blocks to the appropriate large block free list index. */
83
int GC_hblk_fl_from_blocks(blocks_needed)
84
word blocks_needed;
85
{
86
    if (blocks_needed <= UNIQUE_THRESHOLD) return blocks_needed;
87
    if (blocks_needed >= HUGE_THRESHOLD) return N_HBLK_FLS;
88
    return (blocks_needed - UNIQUE_THRESHOLD)/FL_COMPRESSION
89
                                        + 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  /* !USE_MMAP */
99
#   define IS_MAPPED(hhdr) 1
100
# endif /* USE_MUNMAP */
101
 
102
# if !defined(NO_DEBUGGING)
103
void GC_print_hblkfreelist()
104
{
105
    struct hblk * h;
106
    word total_free = 0;
107
    hdr * hhdr;
108
    word sz;
109
    int i;
110
 
111
    for (i = 0; i <= N_HBLK_FLS; ++i) {
112
      h = GC_hblkfreelist[i];
113
#     ifdef USE_MUNMAP
114
        if (0 != h) GC_printf1("Free list %ld:\n",
115
                               (unsigned long)i);
116
#     else
117
        if (0 != h) GC_printf2("Free list %ld (Total size %ld):\n",
118
                               (unsigned long)i,
119
                               (unsigned long)GC_free_bytes[i]);
120
#     endif
121
      while (h != 0) {
122
        hhdr = HDR(h);
123
        sz = hhdr -> hb_sz;
124
        GC_printf2("\t0x%lx size %lu ", (unsigned long)h, (unsigned long)sz);
125
        total_free += sz;
126
        if (GC_is_black_listed(h, HBLKSIZE) != 0) {
127
             GC_printf0("start black listed\n");
128
        } else if (GC_is_black_listed(h, hhdr -> hb_sz) != 0) {
129
             GC_printf0("partially black listed\n");
130
        } else {
131
             GC_printf0("not black listed\n");
132
        }
133
        h = hhdr -> hb_next;
134
      }
135
    }
136
#   ifndef USE_MUNMAP
137
      if (total_free != GC_large_free_bytes) {
138
        GC_printf1("GC_large_free_bytes = %lu (INCONSISTENT!!)\n",
139
                   (unsigned long) GC_large_free_bytes);
140
      }
141
#   endif
142
    GC_printf1("Total of %lu bytes on free list\n", (unsigned long)total_free);
143
}
144
 
145
/* Return the free list index on which the block described by the header */
146
/* appears, or -1 if it appears nowhere.                                 */
147
int free_list_index_of(wanted)
148
hdr * wanted;
149
{
150
    struct hblk * h;
151
    hdr * hhdr;
152
    int i;
153
 
154
    for (i = 0; i <= N_HBLK_FLS; ++i) {
155
      h = GC_hblkfreelist[i];
156
      while (h != 0) {
157
        hhdr = HDR(h);
158
        if (hhdr == wanted) return i;
159
        h = hhdr -> hb_next;
160
      }
161
    }
162
    return -1;
163
}
164
 
165
void GC_dump_regions()
166
{
167
    unsigned i;
168
    ptr_t start, end;
169
    ptr_t p;
170
    size_t bytes;
171
    hdr *hhdr;
172
    for (i = 0; i < GC_n_heap_sects; ++i) {
173
        start = GC_heap_sects[i].hs_start;
174
        bytes = GC_heap_sects[i].hs_bytes;
175
        end = start + bytes;
176
        /* Merge in contiguous sections.        */
177
          while (i+1 < GC_n_heap_sects && GC_heap_sects[i+1].hs_start == end) {
178
            ++i;
179
            end = GC_heap_sects[i].hs_start + GC_heap_sects[i].hs_bytes;
180
          }
181
        GC_printf2("***Section from 0x%lx to 0x%lx\n", start, end);
182
        for (p = start; p < end;) {
183
            hhdr = HDR(p);
184
            GC_printf1("\t0x%lx ", (unsigned long)p);
185
            if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
186
                GC_printf1("Missing header!!(%ld)\n", hhdr);
187
                p += HBLKSIZE;
188
                continue;
189
            }
190
            if (HBLK_IS_FREE(hhdr)) {
191
                int correct_index = GC_hblk_fl_from_blocks(
192
                                        divHBLKSZ(hhdr -> hb_sz));
193
                int actual_index;
194
 
195
                GC_printf1("\tfree block of size 0x%lx bytes",
196
                           (unsigned long)(hhdr -> hb_sz));
197
                if (IS_MAPPED(hhdr)) {
198
                    GC_printf0("\n");
199
                } else {
200
                    GC_printf0("(unmapped)\n");
201
                }
202
                actual_index = free_list_index_of(hhdr);
203
                if (-1 == actual_index) {
204
                    GC_printf1("\t\tBlock not on free list %ld!!\n",
205
                                correct_index);
206
                } else if (correct_index != actual_index) {
207
                    GC_printf2("\t\tBlock on list %ld, should be on %ld!!\n",
208
                               actual_index, correct_index);
209
                }
210
                p += hhdr -> hb_sz;
211
            } else {
212
                GC_printf1("\tused for blocks of size 0x%lx bytes\n",
213
                           (unsigned long)WORDS_TO_BYTES(hhdr -> hb_sz));
214
                p += HBLKSIZE * OBJ_SZ_TO_BLOCKS(hhdr -> hb_sz);
215
            }
216
        }
217
    }
218
}
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
static GC_bool setup_header(hhdr, sz, kind, flags)
226
register hdr * hhdr;
227
word sz;        /* object size in words */
228
int kind;
229
unsigned char flags;
230
{
231
    register word descr;
232
 
233
    /* Add description of valid object pointers */
234
      if (!GC_add_map_entry(sz)) return(FALSE);
235
      hhdr -> hb_map = GC_obj_map[sz > MAXOBJSZ? 0 : sz];
236
 
237
    /* Set size, kind and mark proc fields */
238
      hhdr -> hb_sz = sz;
239
      hhdr -> hb_obj_kind = kind;
240
      hhdr -> hb_flags = flags;
241
      descr = GC_obj_kinds[kind].ok_descriptor;
242
      if (GC_obj_kinds[kind].ok_relocate_descr) descr += WORDS_TO_BYTES(sz);
243
      hhdr -> hb_descr = descr;
244
 
245
    /* Clear mark bits */
246
      GC_clear_hdr_marks(hhdr);
247
 
248
    hhdr -> hb_last_reclaimed = (unsigned short)GC_gc_no;
249
    return(TRUE);
250
}
251
 
252
#define FL_UNKNOWN -1
253
/*
254
 * Remove hhdr from the appropriate free list.
255
 * We assume it is on the nth free list, or on the size
256
 * appropriate free list if n is FL_UNKNOWN.
257
 */
258
void GC_remove_from_fl(hhdr, n)
259
hdr * hhdr;
260
int n;
261
{
262
    int index;
263
 
264
    GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
265
#   ifndef USE_MUNMAP
266
      /* We always need index to mainatin free counts.  */
267
      if (FL_UNKNOWN == n) {
268
          index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
269
      } else {
270
          index = n;
271
      }
272
#   endif
273
    if (hhdr -> hb_prev == 0) {
274
#       ifdef USE_MUNMAP
275
          if (FL_UNKNOWN == n) {
276
            index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
277
          } else {
278
            index = n;
279
          }
280
#       endif
281
        GC_ASSERT(HDR(GC_hblkfreelist[index]) == hhdr);
282
        GC_hblkfreelist[index] = hhdr -> hb_next;
283
    } else {
284
        hdr *phdr;
285
        GET_HDR(hhdr -> hb_prev, phdr);
286
        phdr -> hb_next = hhdr -> hb_next;
287
    }
288
    FREE_ASSERT(GC_free_bytes[index] >= hhdr -> hb_sz);
289
    INCR_FREE_BYTES(index, - (signed_word)(hhdr -> hb_sz));
290
    if (0 != hhdr -> hb_next) {
291
        hdr * nhdr;
292
        GC_ASSERT(!IS_FORWARDING_ADDR_OR_NIL(NHDR(hhdr)));
293
        GET_HDR(hhdr -> hb_next, nhdr);
294
        nhdr -> hb_prev = hhdr -> hb_prev;
295
    }
296
}
297
 
298
/*
299
 * Return a pointer to the free block ending just before h, if any.
300
 */
301
struct hblk * GC_free_block_ending_at(h)
302
struct hblk *h;
303
{
304
    struct hblk * p = h - 1;
305
    hdr * phdr;
306
 
307
    GET_HDR(p, phdr);
308
    while (0 != phdr && IS_FORWARDING_ADDR_OR_NIL(phdr)) {
309
        p = FORWARDED_ADDR(p,phdr);
310
        phdr = HDR(p);
311
    }
312
    if (0 != phdr) {
313
        if(HBLK_IS_FREE(phdr)) {
314
            return p;
315
        } else {
316
            return 0;
317
        }
318
    }
319
    p = GC_prev_block(h - 1);
320
    if (0 != p) {
321
      phdr = HDR(p);
322
      if (HBLK_IS_FREE(phdr) && (ptr_t)p + phdr -> hb_sz == (ptr_t)h) {
323
        return p;
324
      }
325
    }
326
    return 0;
327
}
328
 
329
/*
330
 * Add hhdr to the appropriate free list.
331
 * We maintain individual free lists sorted by address.
332
 */
333
void GC_add_to_fl(h, hhdr)
334
struct hblk *h;
335
hdr * hhdr;
336
{
337
    int index = GC_hblk_fl_from_blocks(divHBLKSZ(hhdr -> hb_sz));
338
    struct hblk *second = GC_hblkfreelist[index];
339
    hdr * second_hdr;
340
#   ifdef GC_ASSERTIONS
341
      struct hblk *next = (struct hblk *)((word)h + hhdr -> hb_sz);
342
      hdr * nexthdr = HDR(next);
343
      struct hblk *prev = GC_free_block_ending_at(h);
344
      hdr * prevhdr = HDR(prev);
345
      GC_ASSERT(nexthdr == 0 || !HBLK_IS_FREE(nexthdr) || !IS_MAPPED(nexthdr));
346
      GC_ASSERT(prev == 0 || !HBLK_IS_FREE(prevhdr) || !IS_MAPPED(prevhdr));
347
#   endif
348
    GC_ASSERT(((hhdr -> hb_sz) & (HBLKSIZE-1)) == 0);
349
    GC_hblkfreelist[index] = h;
350
    INCR_FREE_BYTES(index, hhdr -> hb_sz);
351
    FREE_ASSERT(GC_free_bytes[index] <= GC_large_free_bytes)
352
    hhdr -> hb_next = second;
353
    hhdr -> hb_prev = 0;
354
    if (0 != second) {
355
      GET_HDR(second, second_hdr);
356
      second_hdr -> hb_prev = h;
357
    }
358
    GC_invalidate_map(hhdr);
359
}
360
 
361
#ifdef USE_MUNMAP
362
 
363
/* Unmap blocks that haven't been recently touched.  This is the only way */
364
/* way blocks are ever unmapped.                                          */
365
void GC_unmap_old(void)
366
{
367
    struct hblk * h;
368
    hdr * hhdr;
369
    word sz;
370
    unsigned short last_rec, threshold;
371
    int i;
372
#   define UNMAP_THRESHOLD 6
373
 
374
    for (i = 0; i <= N_HBLK_FLS; ++i) {
375
      for (h = GC_hblkfreelist[i]; 0 != h; h = hhdr -> hb_next) {
376
        hhdr = HDR(h);
377
        if (!IS_MAPPED(hhdr)) continue;
378
        threshold = (unsigned short)(GC_gc_no - UNMAP_THRESHOLD);
379
        last_rec = hhdr -> hb_last_reclaimed;
380
        if ((last_rec > GC_gc_no || last_rec < threshold)
381
            && threshold < GC_gc_no /* not recently wrapped */) {
382
          sz = hhdr -> hb_sz;
383
          GC_unmap((ptr_t)h, sz);
384
          hhdr -> hb_flags |= WAS_UNMAPPED;
385
        }
386
      }
387
    }
388
}
389
 
390
/* Merge all unmapped blocks that are adjacent to other free            */
391
/* blocks.  This may involve remapping, since all blocks are either     */
392
/* fully mapped or fully unmapped.                                      */
393
void GC_merge_unmapped(void)
394
{
395
    struct hblk * h, *next;
396
    hdr * hhdr, *nexthdr;
397
    word size, nextsize;
398
    int i;
399
 
400
    for (i = 0; i <= N_HBLK_FLS; ++i) {
401
      h = GC_hblkfreelist[i];
402
      while (h != 0) {
403
        GET_HDR(h, hhdr);
404
        size = hhdr->hb_sz;
405
        next = (struct hblk *)((word)h + size);
406
        GET_HDR(next, nexthdr);
407
        /* Coalesce with successor, if possible */
408
          if (0 != nexthdr && HBLK_IS_FREE(nexthdr)) {
409
            nextsize = nexthdr -> hb_sz;
410
            if (IS_MAPPED(hhdr)) {
411
              GC_ASSERT(!IS_MAPPED(nexthdr));
412
              /* make both consistent, so that we can merge */
413
                if (size > nextsize) {
414
                  GC_remap((ptr_t)next, nextsize);
415
                } else {
416
                  GC_unmap((ptr_t)h, size);
417
                  hhdr -> hb_flags |= WAS_UNMAPPED;
418
                }
419
            } else if (IS_MAPPED(nexthdr)) {
420
              GC_ASSERT(!IS_MAPPED(hhdr));
421
              if (size > nextsize) {
422
                GC_unmap((ptr_t)next, nextsize);
423
              } else {
424
                GC_remap((ptr_t)h, size);
425
                hhdr -> hb_flags &= ~WAS_UNMAPPED;
426
                hhdr -> hb_last_reclaimed = nexthdr -> hb_last_reclaimed;
427
              }
428
            } else {
429
              /* Unmap any gap in the middle */
430
                GC_unmap_gap((ptr_t)h, size, (ptr_t)next, nexthdr -> hb_sz);
431
            }
432
            /* If they are both unmapped, we merge, but leave unmapped. */
433
            GC_remove_from_fl(hhdr, i);
434
            GC_remove_from_fl(nexthdr, FL_UNKNOWN);
435
            hhdr -> hb_sz += nexthdr -> hb_sz;
436
            GC_remove_header(next);
437
            GC_add_to_fl(h, hhdr);
438
            /* Start over at beginning of list */
439
            h = GC_hblkfreelist[i];
440
          } else /* not mergable with successor */ {
441
            h = hhdr -> hb_next;
442
          }
443
      } /* while (h != 0) ... */
444
    } /* for ... */
445
}
446
 
447
#endif /* USE_MUNMAP */
448
 
449
/*
450
 * Return a pointer to a block starting at h of length bytes.
451
 * Memory for the block is mapped.
452
 * Remove the block from its free list, and return the remainder (if any)
453
 * to its appropriate free list.
454
 * May fail by returning 0.
455
 * The header for the returned block must be set up by the caller.
456
 * If the return value is not 0, then hhdr is the header for it.
457
 */
458
struct hblk * GC_get_first_part(h, hhdr, bytes, index)
459
struct hblk *h;
460
hdr * hhdr;
461
word bytes;
462
int index;
463
{
464
    word total_size = hhdr -> hb_sz;
465
    struct hblk * rest;
466
    hdr * rest_hdr;
467
 
468
    GC_ASSERT((total_size & (HBLKSIZE-1)) == 0);
469
    GC_remove_from_fl(hhdr, index);
470
    if (total_size == bytes) return h;
471
    rest = (struct hblk *)((word)h + bytes);
472
    rest_hdr = GC_install_header(rest);
473
    if (0 == rest_hdr) {
474
        /* This may be very bad news ... */
475
        WARN("Header allocation failed: Dropping block.\n", 0);
476
        return(0);
477
    }
478
    rest_hdr -> hb_sz = total_size - bytes;
479
    rest_hdr -> hb_flags = 0;
480
#   ifdef GC_ASSERTIONS
481
      /* Mark h not free, to avoid assertion about adjacent free blocks. */
482
        hhdr -> hb_map = 0;
483
#   endif
484
    GC_add_to_fl(rest, rest_hdr);
485
    return h;
486
}
487
 
488
/*
489
 * H is a free block.  N points at an address inside it.
490
 * A new header for n has already been set up.  Fix up h's header
491
 * to reflect the fact that it is being split, move it to the
492
 * appropriate free list.
493
 * N replaces h in the original free list.
494
 *
495
 * Nhdr is not completely filled in, since it is about to allocated.
496
 * It may in fact end up on the wrong free list for its size.
497
 * (Hence adding it to a free list is silly.  But this path is hopefully
498
 * rare enough that it doesn't matter.  The code is cleaner this way.)
499
 */
500
void GC_split_block(h, hhdr, n, nhdr, index)
501
struct hblk *h;
502
hdr * hhdr;
503
struct hblk *n;
504
hdr * nhdr;
505
int index;      /* Index of free list */
506
{
507
    word total_size = hhdr -> hb_sz;
508
    word h_size = (word)n - (word)h;
509
    struct hblk *prev = hhdr -> hb_prev;
510
    struct hblk *next = hhdr -> hb_next;
511
 
512
    /* Replace h with n on its freelist */
513
      nhdr -> hb_prev = prev;
514
      nhdr -> hb_next = next;
515
      nhdr -> hb_sz = total_size - h_size;
516
      nhdr -> hb_flags = 0;
517
      if (0 != prev) {
518
        HDR(prev) -> hb_next = n;
519
      } else {
520
        GC_hblkfreelist[index] = n;
521
      }
522
      if (0 != next) {
523
        HDR(next) -> hb_prev = n;
524
      }
525
      INCR_FREE_BYTES(index, -(signed_word)h_size);
526
      FREE_ASSERT(GC_free_bytes[index] > 0);
527
#     ifdef GC_ASSERTIONS
528
        nhdr -> hb_map = 0;      /* Don't fail test for consecutive      */
529
                                /* free blocks in GC_add_to_fl.         */
530
#     endif
531
#   ifdef USE_MUNMAP
532
      hhdr -> hb_last_reclaimed = GC_gc_no;
533
#   endif
534
    hhdr -> hb_sz = h_size;
535
    GC_add_to_fl(h, hhdr);
536
    GC_invalidate_map(nhdr);
537
}
538
 
539
struct hblk * GC_allochblk_nth();
540
 
541
/*
542
 * Allocate (and return pointer to) a heap block
543
 *   for objects of size sz words, searching the nth free list.
544
 *
545
 * NOTE: We set obj_map field in header correctly.
546
 *       Caller is responsible for building an object freelist in block.
547
 *
548
 * Unlike older versions of the collectors, the client is responsible
549
 * for clearing the block, if necessary.
550
 */
551
struct hblk *
552
GC_allochblk(sz, kind, flags)
553
word sz;
554
int kind;
555
unsigned flags;  /* IGNORE_OFF_PAGE or 0 */
556
{
557
    word blocks = OBJ_SZ_TO_BLOCKS(sz);
558
    int start_list = GC_hblk_fl_from_blocks(blocks);
559
    int i;
560
    for (i = start_list; i <= N_HBLK_FLS; ++i) {
561
        struct hblk * result = GC_allochblk_nth(sz, kind, flags, i);
562
        if (0 != result) {
563
            return result;
564
        }
565
    }
566
    return 0;
567
}
568
/*
569
 * The same, but with search restricted to nth free list.
570
 */
571
struct hblk *
572
GC_allochblk_nth(sz, kind, flags, n)
573
word sz;
574
int kind;
575
unsigned char flags;  /* IGNORE_OFF_PAGE or 0 */
576
int n;
577
{
578
    register struct hblk *hbp;
579
    register hdr * hhdr;                /* Header corr. to hbp */
580
    register struct hblk *thishbp;
581
    register hdr * thishdr;             /* Header corr. to hbp */
582
    signed_word size_needed;    /* number of bytes in requested objects */
583
    signed_word size_avail;     /* bytes available in this block        */
584
 
585
    size_needed = HBLKSIZE * OBJ_SZ_TO_BLOCKS(sz);
586
 
587
    /* search for a big enough block in free list */
588
        hbp = GC_hblkfreelist[n];
589
        for(; 0 != hbp; hbp = hhdr -> hb_next) {
590
            GET_HDR(hbp, hhdr);
591
            size_avail = hhdr->hb_sz;
592
            if (size_avail < size_needed) continue;
593
            if (size_avail != size_needed
594
                && !GC_use_entire_heap
595
                && !GC_dont_gc
596
                && USED_HEAP_SIZE >= GC_requested_heapsize
597
                && !TRUE_INCREMENTAL && GC_should_collect()) {
598
#               ifdef USE_MUNMAP
599
                    continue;
600
#               else
601
                    /* If we have enough large blocks left to cover any */
602
                    /* previous request for large blocks, we go ahead   */
603
                    /* and split.  Assuming a steady state, that should */
604
                    /* be safe.  It means that we can use the full      */
605
                    /* heap if we allocate only small objects.          */
606
                    if (!GC_enough_large_bytes_left(GC_large_allocd_bytes, n)) {
607
                      continue;
608
                    }
609
                    /* If we are deallocating lots of memory from       */
610
                    /* finalizers, fail and collect sooner rather       */
611
                    /* than later.                                      */
612
                    if (WORDS_TO_BYTES(GC_finalizer_mem_freed)
613
                        > (GC_heapsize >> 4))  {
614
                      continue;
615
                    }
616
#               endif /* !USE_MUNMAP */
617
            }
618
            /* If the next heap block is obviously better, go on.       */
619
            /* This prevents us from disassembling a single large block */
620
            /* to get tiny blocks.                                      */
621
            {
622
              signed_word next_size;
623
 
624
              thishbp = hhdr -> hb_next;
625
              if (thishbp != 0) {
626
                GET_HDR(thishbp, thishdr);
627
                next_size = (signed_word)(thishdr -> hb_sz);
628
                if (next_size < size_avail
629
                  && next_size >= size_needed
630
                  && !GC_is_black_listed(thishbp, (word)size_needed)) {
631
                  continue;
632
                }
633
              }
634
            }
635
            if ( !IS_UNCOLLECTABLE(kind) &&
636
                 (kind != PTRFREE || size_needed > MAX_BLACK_LIST_ALLOC)) {
637
              struct hblk * lasthbp = hbp;
638
              ptr_t search_end = (ptr_t)hbp + size_avail - size_needed;
639
              signed_word orig_avail = size_avail;
640
              signed_word eff_size_needed = ((flags & IGNORE_OFF_PAGE)?
641
                                                HBLKSIZE
642
                                                : size_needed);
643
 
644
 
645
              while ((ptr_t)lasthbp <= search_end
646
                     && (thishbp = GC_is_black_listed(lasthbp,
647
                                                      (word)eff_size_needed))
648
                        != 0) {
649
                lasthbp = thishbp;
650
              }
651
              size_avail -= (ptr_t)lasthbp - (ptr_t)hbp;
652
              thishbp = lasthbp;
653
              if (size_avail >= size_needed) {
654
                if (thishbp != hbp &&
655
 
656
                  /* Make sure it's mapped before we mangle it. */
657
#                   ifdef USE_MUNMAP
658
                      if (!IS_MAPPED(hhdr)) {
659
                        GC_remap((ptr_t)hbp, hhdr -> hb_sz);
660
                        hhdr -> hb_flags &= ~WAS_UNMAPPED;
661
                      }
662
#                   endif
663
                  /* Split the block at thishbp */
664
                      GC_split_block(hbp, hhdr, thishbp, thishdr, n);
665
                  /* Advance to thishbp */
666
                      hbp = thishbp;
667
                      hhdr = thishdr;
668
                      /* We must now allocate thishbp, since it may     */
669
                      /* be on the wrong free list.                     */
670
                }
671
              } else if (size_needed > (signed_word)BL_LIMIT
672
                         && orig_avail - size_needed
673
                            > (signed_word)BL_LIMIT) {
674
                /* Punt, since anything else risks unreasonable heap growth. */
675
                if (++GC_large_alloc_warn_suppressed
676
                    >= GC_large_alloc_warn_interval) {
677
                  WARN("Repeated allocation of very large block "
678
                       "(appr. size %ld):\n"
679
                       "\tMay lead to memory leak and poor performance.\n",
680
                       size_needed);
681
                  GC_large_alloc_warn_suppressed = 0;
682
                }
683
                size_avail = orig_avail;
684
              } else if (size_avail == 0 && size_needed == HBLKSIZE
685
                         && IS_MAPPED(hhdr)) {
686
                if (!GC_find_leak) {
687
                  static unsigned count = 0;
688
 
689
                  /* The block is completely blacklisted.  We need      */
690
                  /* to drop some such blocks, since otherwise we spend */
691
                  /* all our time traversing them if pointerfree        */
692
                  /* blocks are unpopular.                              */
693
                  /* A dropped block will be reconsidered at next GC.   */
694
                  if ((++count & 3) == 0) {
695
                    /* Allocate and drop the block in small chunks, to  */
696
                    /* maximize the chance that we will recover some    */
697
                    /* later.                                           */
698
                      word total_size = hhdr -> hb_sz;
699
                      struct hblk * limit = hbp + divHBLKSZ(total_size);
700
                      struct hblk * h;
701
                      struct hblk * prev = hhdr -> hb_prev;
702
 
703
                      GC_words_wasted += BYTES_TO_WORDS(total_size);
704
                      GC_large_free_bytes -= total_size;
705
                      GC_remove_from_fl(hhdr, n);
706
                      for (h = hbp; h < limit; h++) {
707
                        if (h == hbp || 0 != (hhdr = GC_install_header(h))) {
708
                          (void) setup_header(
709
                                  hhdr,
710
                                  BYTES_TO_WORDS(HBLKSIZE),
711
                                  PTRFREE, 0); /* Cant fail */
712
                          if (GC_debugging_started) {
713
                            BZERO(h, HBLKSIZE);
714
                          }
715
                        }
716
                      }
717
                    /* Restore hbp to point at free block */
718
                      hbp = prev;
719
                      if (0 == hbp) {
720
                        return GC_allochblk_nth(sz, kind, flags, n);
721
                      }
722
                      hhdr = HDR(hbp);
723
                  }
724
                }
725
              }
726
            }
727
            if( size_avail >= size_needed ) {
728
#               ifdef USE_MUNMAP
729
                  if (!IS_MAPPED(hhdr)) {
730
                    GC_remap((ptr_t)hbp, hhdr -> hb_sz);
731
                    hhdr -> hb_flags &= ~WAS_UNMAPPED;
732
                  }
733
#               endif
734
                /* hbp may be on the wrong freelist; the parameter n    */
735
                /* is important.                                        */
736
                hbp = GC_get_first_part(hbp, hhdr, size_needed, n);
737
                break;
738
            }
739
        }
740
 
741
    if (0 == hbp) return 0;
742
 
743
    /* Add it to map of valid blocks */
744
        if (!GC_install_counts(hbp, (word)size_needed)) return(0);
745
        /* This leaks memory under very rare conditions. */
746
 
747
    /* Set up header */
748
        if (!setup_header(hhdr, sz, kind, flags)) {
749
            GC_remove_counts(hbp, (word)size_needed);
750
            return(0); /* ditto */
751
        }
752
 
753
    /* Notify virtual dirty bit implementation that we are about to write.  */
754
    /* Ensure that pointerfree objects are not protected if it's avoidable. */
755
        GC_remove_protection(hbp, divHBLKSZ(size_needed),
756
                             (hhdr -> hb_descr == 0) /* pointer-free */);
757
 
758
    /* We just successfully allocated a block.  Restart count of        */
759
    /* consecutive failures.                                            */
760
    {
761
        extern unsigned GC_fail_count;
762
 
763
        GC_fail_count = 0;
764
    }
765
 
766
    GC_large_free_bytes -= size_needed;
767
 
768
    GC_ASSERT(IS_MAPPED(hhdr));
769
    return( hbp );
770
}
771
 
772
struct hblk * GC_freehblk_ptr = 0;  /* Search position hint for GC_freehblk */
773
 
774
/*
775
 * Free a heap block.
776
 *
777
 * Coalesce the block with its neighbors if possible.
778
 *
779
 * All mark words are assumed to be cleared.
780
 */
781
void
782
GC_freehblk(hbp)
783
struct hblk *hbp;
784
{
785
struct hblk *next, *prev;
786
hdr *hhdr, *prevhdr, *nexthdr;
787
signed_word size;
788
 
789
 
790
    GET_HDR(hbp, hhdr);
791
    size = hhdr->hb_sz;
792
    size = HBLKSIZE * OBJ_SZ_TO_BLOCKS(size);
793
    GC_remove_counts(hbp, (word)size);
794
    hhdr->hb_sz = size;
795
#   ifdef USE_MUNMAP
796
      hhdr -> hb_last_reclaimed = GC_gc_no;
797
#   endif
798
 
799
    /* Check for duplicate deallocation in the easy case */
800
      if (HBLK_IS_FREE(hhdr)) {
801
        GC_printf1("Duplicate large block deallocation of 0x%lx\n",
802
                   (unsigned long) hbp);
803
        ABORT("Duplicate large block deallocation");
804
      }
805
 
806
    GC_ASSERT(IS_MAPPED(hhdr));
807
    GC_invalidate_map(hhdr);
808
    next = (struct hblk *)((word)hbp + size);
809
    GET_HDR(next, nexthdr);
810
    prev = GC_free_block_ending_at(hbp);
811
    /* Coalesce with successor, if possible */
812
      if(0 != nexthdr && HBLK_IS_FREE(nexthdr) && IS_MAPPED(nexthdr)) {
813
        GC_remove_from_fl(nexthdr, FL_UNKNOWN);
814
        hhdr -> hb_sz += nexthdr -> hb_sz;
815
        GC_remove_header(next);
816
      }
817
    /* Coalesce with predecessor, if possible. */
818
      if (0 != prev) {
819
        prevhdr = HDR(prev);
820
        if (IS_MAPPED(prevhdr)) {
821
          GC_remove_from_fl(prevhdr, FL_UNKNOWN);
822
          prevhdr -> hb_sz += hhdr -> hb_sz;
823
#         ifdef USE_MUNMAP
824
            prevhdr -> hb_last_reclaimed = GC_gc_no;
825
#         endif
826
          GC_remove_header(hbp);
827
          hbp = prev;
828
          hhdr = prevhdr;
829
        }
830
      }
831
    /* FIXME: It is not clear we really always want to do these merges  */
832
    /* with -DUSE_MUNMAP, since it updates ages and hence prevents      */
833
    /* unmapping.                                                       */
834
 
835
    GC_large_free_bytes += size;
836
    GC_add_to_fl(hbp, hhdr);
837
}
838
 

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