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c7743d02 HWN |
1 | /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002 Free Software Foundation, Inc. |
2 | * | |
3 | * This program is free software; you can redistribute it and/or modify | |
4 | * it under the terms of the GNU General Public License as published by | |
5 | * the Free Software Foundation; either version 2, or (at your option) | |
6 | * any later version. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
11 | * GNU General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License | |
14 | * along with this software; see the file COPYING. If not, write to | |
15 | * the Free Software Foundation, Inc., 59 Temple Place, Suite 330, | |
16 | * Boston, MA 02111-1307 USA | |
17 | * | |
18 | * As a special exception, the Free Software Foundation gives permission | |
19 | * for additional uses of the text contained in its release of GUILE. | |
20 | * | |
21 | * The exception is that, if you link the GUILE library with other files | |
22 | * to produce an executable, this does not by itself cause the | |
23 | * resulting executable to be covered by the GNU General Public License. | |
24 | * Your use of that executable is in no way restricted on account of | |
25 | * linking the GUILE library code into it. | |
26 | * | |
27 | * This exception does not however invalidate any other reasons why | |
28 | * the executable file might be covered by the GNU General Public License. | |
29 | * | |
30 | * This exception applies only to the code released by the | |
31 | * Free Software Foundation under the name GUILE. If you copy | |
32 | * code from other Free Software Foundation releases into a copy of | |
33 | * GUILE, as the General Public License permits, the exception does | |
34 | * not apply to the code that you add in this way. To avoid misleading | |
35 | * anyone as to the status of such modified files, you must delete | |
36 | * this exception notice from them. | |
37 | * | |
38 | * If you write modifications of your own for GUILE, it is your choice | |
39 | * whether to permit this exception to apply to your modifications. | |
40 | * If you do not wish that, delete this exception notice. */ | |
41 | ||
42 | #include <assert.h> | |
43 | #include <stdio.h> | |
44 | #include <string.h> | |
45 | ||
46 | #include "libguile/_scm.h" | |
47 | #include "libguile/pairs.h" | |
48 | #include "libguile/gc.h" | |
49 | #include "libguile/private-gc.h" | |
50 | ||
51 | ||
52 | ||
c7743d02 HWN |
53 | |
54 | ||
55 | size_t scm_max_segment_size; | |
56 | ||
57 | scm_t_heap_segment * | |
58 | scm_i_make_empty_heap_segment (scm_t_cell_type_statistics *fl) | |
59 | { | |
60 | scm_t_heap_segment * shs = malloc (sizeof (scm_t_heap_segment)); | |
61 | ||
62 | if (!shs) | |
63 | { | |
64 | fprintf (stderr, "scm_i_get_new_heap_segment: out of memory.\n"); | |
65 | abort (); | |
66 | } | |
67 | ||
68 | shs->bounds[0] = NULL; | |
69 | shs->bounds[1] = NULL; | |
70 | shs->malloced = NULL; | |
71 | shs->span = fl->span; | |
72 | shs->freelist = fl; | |
73 | shs->next_free_card = NULL; | |
74 | ||
75 | return shs; | |
76 | } | |
77 | ||
78 | ||
79 | /* | |
80 | Fill SEGMENT with memory both for data and mark bits. | |
81 | ||
82 | RETURN: 1 on success, 0 failure | |
83 | */ | |
84 | int | |
85 | scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested) | |
86 | { | |
87 | /* | |
88 | round upwards | |
89 | */ | |
90 | int card_data_cell_count = (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS); | |
91 | int card_count =1 + (requested / sizeof (scm_t_cell)) / card_data_cell_count; | |
92 | ||
93 | /* | |
94 | one card extra due to alignment | |
95 | */ | |
96 | size_t mem_needed = (1+card_count) * SCM_GC_SIZEOF_CARD | |
97 | + SCM_GC_CARD_BVEC_SIZE_IN_LONGS * card_count * SCM_SIZEOF_LONG | |
98 | ; | |
99 | scm_t_c_bvec_long * bvec_ptr = 0; | |
100 | scm_t_cell * memory = 0; | |
101 | ||
102 | /* | |
103 | We use malloc to alloc the heap. On GNU libc this is | |
104 | equivalent to mmapping /dev/zero | |
105 | */ | |
106 | SCM_SYSCALL (memory = (scm_t_cell * ) calloc (1, mem_needed)); | |
107 | ||
108 | if (memory == NULL) | |
109 | return 0; | |
110 | ||
111 | segment->malloced = memory; | |
112 | segment->bounds[0] = SCM_GC_CARD_UP (memory); | |
113 | segment->bounds[1] = segment->bounds[0] + card_count * SCM_GC_CARD_N_CELLS; | |
114 | ||
115 | segment->freelist->heap_size += scm_i_segment_cell_count (segment); | |
116 | ||
117 | bvec_ptr = (scm_t_c_bvec_long*) segment->bounds[1]; | |
118 | ||
1383773b HWN |
119 | /* |
120 | Don't init the mem or the bitvector. This is handled by lazy | |
121 | sweeping. | |
122 | */ | |
123 | ||
c7743d02 HWN |
124 | segment->next_free_card = segment->bounds[0]; |
125 | segment->first_time = 1; | |
126 | return 1; | |
127 | } | |
128 | ||
129 | int | |
130 | scm_i_segment_card_count (scm_t_heap_segment * seg) | |
131 | { | |
132 | return (seg->bounds[1] - seg->bounds[0]) / SCM_GC_CARD_N_CELLS; | |
133 | } | |
134 | ||
135 | /* | |
136 | Return the number of available single-cell data cells. | |
137 | */ | |
138 | int | |
139 | scm_i_segment_cell_count (scm_t_heap_segment * seg) | |
140 | { | |
141 | return scm_i_segment_card_count (seg) * (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS) | |
142 | + ((seg->span == 2) ? -1 : 0); | |
143 | } | |
144 | ||
145 | void | |
146 | scm_i_clear_segment_mark_space (scm_t_heap_segment *seg) | |
147 | { | |
148 | scm_t_cell * markspace = seg->bounds[1]; | |
149 | ||
150 | memset (markspace, 0x00, | |
151 | scm_i_segment_card_count (seg) * SCM_GC_CARD_BVEC_SIZE_IN_LONGS * SCM_SIZEOF_LONG); | |
152 | } | |
153 | ||
154 | /* | |
155 | RETURN: | |
156 | ||
157 | Freelist. | |
158 | */ | |
159 | SCM | |
160 | scm_i_sweep_some_cards (scm_t_heap_segment *seg) | |
161 | { | |
162 | SCM cells = SCM_EOL; | |
163 | int threshold = 512; | |
164 | int collected = 0; | |
1383773b HWN |
165 | int (*sweeper) (scm_t_cell *, SCM *, scm_t_heap_segment* ) |
166 | = (seg->first_time) ? &scm_i_init_card_freelist : &scm_i_sweep_card; | |
c7743d02 HWN |
167 | |
168 | scm_t_cell * next_free = seg->next_free_card; | |
169 | int cards_swept = 0; | |
170 | ||
171 | while (collected < threshold && next_free < seg->bounds[1]) | |
172 | { | |
1383773b | 173 | collected += (*sweeper) (next_free, &cells, seg); |
c7743d02 HWN |
174 | next_free += SCM_GC_CARD_N_CELLS; |
175 | cards_swept ++; | |
176 | } | |
177 | ||
178 | scm_gc_cells_swept += cards_swept * (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS); | |
179 | scm_gc_cells_collected += collected * seg->span; | |
c2cbcc57 HWN |
180 | |
181 | if (!seg->first_time) | |
182 | scm_cells_allocated -= collected * seg->span; | |
183 | ||
c7743d02 | 184 | seg->freelist->collected += collected * seg->span; |
c2cbcc57 | 185 | |
c7743d02 HWN |
186 | |
187 | if(next_free == seg->bounds[1]) | |
188 | { | |
189 | seg->first_time = 0; | |
190 | } | |
191 | ||
192 | seg->next_free_card = next_free; | |
193 | return cells; | |
194 | } | |
195 | ||
196 | ||
197 | /* | |
198 | Force a sweep of this entire segment. This doesn't modify sweep | |
199 | statistics, it just frees the memory pointed to by to-be-swept | |
200 | cells. | |
201 | ||
c2cbcc57 HWN |
202 | Implementation is slightly ugh. |
203 | ||
204 | FIXME: if you do scm_i_sweep_segment(), and then allocate from this | |
205 | segment again, the statistics are off. | |
c7743d02 HWN |
206 | */ |
207 | void | |
208 | scm_i_sweep_segment (scm_t_heap_segment * seg) | |
209 | { | |
210 | scm_t_cell * p = seg->next_free_card; | |
211 | int yield = scm_gc_cells_collected; | |
212 | int coll = seg->freelist->collected; | |
f2893a25 | 213 | unsigned long alloc = scm_cells_allocated ; |
c2cbcc57 | 214 | |
c7743d02 HWN |
215 | while (scm_i_sweep_some_cards (seg) != SCM_EOL) |
216 | ; | |
217 | ||
218 | scm_gc_cells_collected = yield; | |
c2cbcc57 | 219 | scm_cells_allocated = alloc; |
c7743d02 HWN |
220 | seg->freelist->collected = coll; |
221 | ||
222 | seg->next_free_card =p; | |
223 | } | |
224 | ||
225 | void | |
226 | scm_i_sweep_all_segments (char const *reason) | |
227 | { | |
228 | int i= 0; | |
229 | ||
230 | for (i = 0; i < scm_i_heap_segment_table_size; i++) | |
231 | { | |
232 | scm_i_sweep_segment (scm_i_heap_segment_table[i]); | |
233 | } | |
234 | } | |
235 | ||
236 | ||
237 | /* | |
238 | Heap segment table. | |
239 | ||
240 | The table is sorted by the address of the data itself. This makes | |
241 | for easy lookups. This is not portable: according to ANSI C, | |
242 | pointers can only be compared within the same object (i.e. the same | |
243 | block of malloced memory.). For machines with weird architectures, | |
244 | this should be revised. | |
245 | ||
246 | (Apparently, for this reason 1.6 and earlier had macros for pointer | |
247 | comparison. ) | |
248 | ||
249 | perhaps it is worthwhile to remove the 2nd level of indirection in | |
250 | the table, but this certainly makes for cleaner code. | |
251 | */ | |
252 | scm_t_heap_segment ** scm_i_heap_segment_table; | |
253 | size_t scm_i_heap_segment_table_size; | |
254 | scm_t_cell *lowest_cell; | |
255 | scm_t_cell *highest_cell; | |
256 | ||
257 | ||
258 | void | |
259 | scm_i_clear_mark_space (void) | |
260 | { | |
261 | int i = 0; | |
262 | for (; i < scm_i_heap_segment_table_size; i++) | |
263 | { | |
264 | scm_i_clear_segment_mark_space (scm_i_heap_segment_table[i]); | |
265 | } | |
266 | } | |
267 | ||
268 | ||
269 | /* | |
270 | RETURN: index of inserted segment. | |
271 | */ | |
272 | int | |
273 | scm_i_insert_segment (scm_t_heap_segment * seg) | |
274 | { | |
275 | size_t size = (scm_i_heap_segment_table_size + 1) * sizeof (scm_t_heap_segment *); | |
276 | SCM_SYSCALL(scm_i_heap_segment_table = ((scm_t_heap_segment **) | |
277 | realloc ((char *)scm_i_heap_segment_table, size))); | |
278 | ||
279 | /* | |
280 | We can't alloc 4 more bytes. This is hopeless. | |
281 | */ | |
282 | if (!scm_i_heap_segment_table) | |
283 | { | |
284 | fprintf (stderr, "scm_i_get_new_heap_segment: Could not grow heap segment table.\n"); | |
285 | abort (); | |
286 | } | |
287 | ||
288 | if (!lowest_cell) | |
289 | { | |
290 | lowest_cell = seg->bounds[0]; | |
291 | highest_cell = seg->bounds[1]; | |
292 | } | |
293 | else | |
294 | { | |
295 | lowest_cell = SCM_MIN (lowest_cell, seg->bounds[0]); | |
296 | highest_cell = SCM_MAX (highest_cell, seg->bounds[1]); | |
297 | } | |
298 | ||
ffd72400 | 299 | |
c7743d02 HWN |
300 | { |
301 | int i = 0; | |
302 | int j = 0; | |
303 | ||
304 | while (i < scm_i_heap_segment_table_size | |
305 | && scm_i_heap_segment_table[i]->bounds[0] <= seg->bounds[0]) | |
306 | i++; | |
ffd72400 HWN |
307 | |
308 | /* | |
309 | We insert a new entry; if that happens to be before the | |
310 | "current" segment of a freelist, we must move the freelist index | |
311 | as well. | |
312 | */ | |
313 | if (scm_i_master_freelist.heap_segment_idx >= i) | |
314 | scm_i_master_freelist.heap_segment_idx ++; | |
315 | if (scm_i_master_freelist2.heap_segment_idx >= i) | |
316 | scm_i_master_freelist2.heap_segment_idx ++; | |
317 | ||
c7743d02 HWN |
318 | for (j = scm_i_heap_segment_table_size; j > i; --j) |
319 | scm_i_heap_segment_table[j] = scm_i_heap_segment_table[j - 1]; | |
320 | ||
321 | scm_i_heap_segment_table [i] = seg; | |
322 | scm_i_heap_segment_table_size ++; | |
323 | ||
324 | return i; | |
325 | } | |
326 | } | |
327 | ||
328 | SCM | |
329 | scm_i_sweep_some_segments (scm_t_cell_type_statistics * fl) | |
330 | { | |
331 | int i = fl->heap_segment_idx; | |
332 | SCM collected =SCM_EOL; | |
333 | ||
334 | if (i == -1) | |
335 | i++; | |
336 | ||
337 | for (; | |
338 | i < scm_i_heap_segment_table_size; i++) | |
339 | { | |
340 | if (scm_i_heap_segment_table[i]->freelist != fl) | |
341 | continue; | |
342 | ||
343 | collected = scm_i_sweep_some_cards (scm_i_heap_segment_table[i]); | |
344 | ||
345 | ||
346 | if (collected != SCM_EOL) /* Don't increment i */ | |
347 | break; | |
348 | } | |
349 | ||
350 | fl->heap_segment_idx = i; | |
351 | ||
352 | return collected; | |
353 | } | |
354 | ||
355 | ||
356 | ||
357 | ||
358 | void | |
359 | scm_i_reset_segments (void) | |
360 | { | |
361 | int i = 0; | |
362 | for (; i < scm_i_heap_segment_table_size; i++) | |
363 | { | |
364 | scm_t_heap_segment * seg = scm_i_heap_segment_table[i]; | |
365 | seg->next_free_card = seg->bounds[0]; | |
366 | } | |
367 | } | |
368 | ||
369 | ||
370 | /* | |
371 | Determine whether the given value does actually represent a cell in | |
372 | some heap segment. If this is the case, the number of the heap | |
373 | segment is returned. Otherwise, -1 is returned. Binary search is | |
374 | used to determine the heap segment that contains the cell. | |
375 | ||
376 | ||
377 | I think this function is too long to be inlined. --hwn | |
378 | */ | |
379 | long int | |
380 | scm_i_find_heap_segment_containing_object (SCM obj) | |
381 | { | |
382 | if (!CELL_P (obj)) | |
383 | return -1; | |
384 | ||
385 | if ((scm_t_cell* ) obj < lowest_cell || (scm_t_cell*) obj >= highest_cell) | |
386 | return -1; | |
387 | ||
388 | ||
389 | { | |
390 | scm_t_cell * ptr = SCM2PTR (obj); | |
391 | unsigned long int i = 0; | |
392 | unsigned long int j = scm_i_heap_segment_table_size - 1; | |
393 | ||
394 | if (ptr < scm_i_heap_segment_table[i]->bounds[0]) | |
395 | return -1; | |
396 | else if (scm_i_heap_segment_table[j]->bounds[1] <= ptr) | |
397 | return -1; | |
398 | else | |
399 | { | |
400 | while (i < j) | |
401 | { | |
402 | if (ptr < scm_i_heap_segment_table[i]->bounds[1]) | |
403 | { | |
404 | break; | |
405 | } | |
406 | else if (scm_i_heap_segment_table[j]->bounds[0] <= ptr) | |
407 | { | |
408 | i = j; | |
409 | break; | |
410 | } | |
411 | else | |
412 | { | |
413 | unsigned long int k = (i + j) / 2; | |
414 | ||
415 | if (k == i) | |
416 | return -1; | |
417 | else if (ptr < scm_i_heap_segment_table[k]->bounds[1]) | |
418 | { | |
419 | j = k; | |
420 | ++i; | |
421 | if (ptr < scm_i_heap_segment_table[i]->bounds[0]) | |
422 | return -1; | |
423 | } | |
424 | else if (scm_i_heap_segment_table[k]->bounds[0] <= ptr) | |
425 | { | |
426 | i = k; | |
427 | --j; | |
428 | if (scm_i_heap_segment_table[j]->bounds[1] <= ptr) | |
429 | return -1; | |
430 | } | |
431 | } | |
432 | } | |
433 | ||
1383773b | 434 | if (!SCM_DOUBLECELL_ALIGNED_P (obj) && scm_i_heap_segment_table[i]->span == 2) |
c7743d02 HWN |
435 | return -1; |
436 | else if (SCM_GC_IN_CARD_HEADERP (ptr)) | |
437 | return -1; | |
438 | else | |
439 | return i; | |
440 | } | |
441 | } | |
442 | } | |
443 | ||
444 | ||
445 | /* | |
446 | Important entry point: try to grab some memory, and make it into a | |
447 | segment. | |
448 | ||
449 | RETURN: the index of the segment. | |
450 | */ | |
451 | int | |
452 | scm_i_get_new_heap_segment (scm_t_cell_type_statistics *freelist, policy_on_error error_policy) | |
453 | { | |
454 | size_t len; | |
455 | ||
456 | if (scm_gc_heap_lock) | |
457 | { | |
458 | /* Critical code sections (such as the garbage collector) aren't | |
459 | * supposed to add heap segments. | |
460 | */ | |
461 | fprintf (stderr, "scm_i_get_new_heap_segment: Can not extend locked heap.\n"); | |
462 | abort (); | |
463 | } | |
464 | ||
c7743d02 HWN |
465 | { |
466 | /* Assure that the new segment is predicted to be large enough. | |
467 | * | |
468 | * New yield should at least equal GC fraction of new heap size, i.e. | |
469 | * | |
470 | * y + dh > f * (h + dh) | |
471 | * | |
472 | * y : yield | |
473 | * f : min yield fraction | |
474 | * h : heap size | |
475 | * dh : size of new heap segment | |
476 | * | |
477 | * This gives dh > (f * h - y) / (1 - f) | |
478 | */ | |
38d1262a HWN |
479 | float f = freelist->min_yield_fraction / 100.0; |
480 | float h = SCM_HEAP_SIZE; | |
481 | float min_cells | |
482 | = (f * h - scm_gc_cells_collected) / (1.0 - f); | |
c7743d02 HWN |
483 | |
484 | /* Make heap grow with factor 1.5 */ | |
485 | len = freelist->heap_size / 2; | |
486 | #ifdef DEBUGINFO | |
487 | fprintf (stderr, "(%ld < %ld)", (long) len, (long) min_cells); | |
488 | #endif | |
489 | ||
c7743d02 | 490 | if (len < min_cells) |
38d1262a | 491 | len = (unsigned long) min_cells; |
c7743d02 HWN |
492 | len *= sizeof (scm_t_cell); |
493 | /* force new sampling */ | |
494 | freelist->collected = LONG_MAX; | |
495 | } | |
496 | ||
4a5309c9 | 497 | if (len < SCM_MIN_HEAP_SEG_SIZE) |
67329a9e | 498 | len = SCM_MIN_HEAP_SEG_SIZE; |
c7743d02 HWN |
499 | |
500 | { | |
c7743d02 | 501 | scm_t_heap_segment * seg = scm_i_make_empty_heap_segment (freelist); |
c7743d02 HWN |
502 | |
503 | /* Allocate with decaying ambition. */ | |
67329a9e | 504 | while (len >= SCM_MIN_HEAP_SEG_SIZE) |
c7743d02 HWN |
505 | { |
506 | if (scm_i_initialize_heap_segment_data (seg, len)) | |
507 | { | |
508 | return scm_i_insert_segment (seg); | |
509 | } | |
510 | ||
511 | len /= 2; | |
512 | } | |
513 | } | |
514 | ||
515 | if (error_policy == abort_on_error) | |
516 | { | |
517 | fprintf (stderr, "scm_i_get_new_heap_segment: Could not grow heap.\n"); | |
518 | abort (); | |
519 | } | |
520 | return -1; | |
521 | } | |
522 | ||
c7743d02 | 523 | void |
dac04e9f | 524 | scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist) |
c7743d02 HWN |
525 | { |
526 | scm_t_heap_segment * seg = scm_i_make_empty_heap_segment (freelist); | |
dac04e9f HWN |
527 | |
528 | if (init_heap_size < 1) | |
529 | { | |
530 | init_heap_size = SCM_DEFAULT_INIT_HEAP_SIZE_1; | |
531 | } | |
c7743d02 HWN |
532 | |
533 | if (scm_i_initialize_heap_segment_data (seg, init_heap_size)) | |
534 | { | |
535 | freelist->heap_segment_idx = scm_i_insert_segment (seg); | |
536 | } | |
537 | ||
538 | /* | |
539 | Why the fuck try twice? --hwn | |
540 | */ | |
541 | if (!seg->malloced) | |
542 | { | |
543 | scm_i_initialize_heap_segment_data (seg, SCM_HEAP_SEG_SIZE); | |
544 | } | |
545 | ||
546 | if (freelist->min_yield_fraction) | |
547 | freelist->min_yield = (freelist->heap_size * freelist->min_yield_fraction | |
548 | / 100); | |
549 | } |