1 /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2006, 2008 Free Software Foundation, Inc.
3 * This library is free software; you can redistribute it and/or
4 * modify it under the terms of the GNU Lesser General Public
5 * License as published by the Free Software Foundation; either
6 * version 2.1 of the License, or (at your option) any later version.
8 * This library 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 GNU
11 * Lesser General Public License for more details.
13 * You should have received a copy of the GNU Lesser General Public
14 * License along with this library; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 #include "libguile/_scm.h"
27 #include "libguile/pairs.h"
28 #include "libguile/gc.h"
29 #include "libguile/private-gc.h"
35 size_t scm_max_segment_size;
38 scm_i_make_empty_heap_segment (scm_t_cell_type_statistics *fl)
40 scm_t_heap_segment * shs = malloc (sizeof (scm_t_heap_segment));
44 fprintf (stderr, "scm_i_get_new_heap_segment: out of memory.\n");
48 shs->bounds[0] = NULL;
49 shs->bounds[1] = NULL;
53 shs->next_free_card = NULL;
60 scm_i_heap_segment_statistics (scm_t_heap_segment *seg, SCM tab)
62 scm_t_cell *p = seg->bounds[0];
63 while (p < seg->bounds[1])
65 scm_i_card_statistics (p, tab, seg);
66 p += SCM_GC_CARD_N_CELLS;
73 Fill SEGMENT with memory both for data and mark bits.
75 RETURN: 1 on success, 0 failure
78 scm_i_initialize_heap_segment_data (scm_t_heap_segment * segment, size_t requested)
83 int card_data_cell_count = (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS);
84 int card_count =1 + (requested / sizeof (scm_t_cell)) / card_data_cell_count;
87 one card extra due to alignment
89 size_t mem_needed = (1+card_count) * SCM_GC_SIZEOF_CARD
90 + SCM_GC_CARD_BVEC_SIZE_IN_LONGS * card_count * SCM_SIZEOF_LONG
92 scm_t_c_bvec_long * bvec_ptr = 0;
93 scm_t_cell * memory = 0;
96 We use calloc to alloc the heap. On GNU libc this is
97 equivalent to mmapping /dev/zero
99 SCM_SYSCALL (memory = (scm_t_cell * ) calloc (1, mem_needed));
104 segment->malloced = memory;
105 segment->bounds[0] = SCM_GC_CARD_UP (memory);
106 segment->bounds[1] = segment->bounds[0] + card_count * SCM_GC_CARD_N_CELLS;
108 segment->freelist->heap_size += scm_i_segment_cell_count (segment);
110 bvec_ptr = (scm_t_c_bvec_long*) segment->bounds[1];
113 Don't init the mem or the bitvector. This is handled by lazy
117 segment->next_free_card = segment->bounds[0];
118 segment->first_time = 1;
123 scm_i_segment_card_count (scm_t_heap_segment * seg)
125 return (seg->bounds[1] - seg->bounds[0]) / SCM_GC_CARD_N_CELLS;
129 Return the number of available single-cell data cells.
132 scm_i_segment_cell_count (scm_t_heap_segment * seg)
134 return scm_i_segment_card_count (seg) * (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS)
135 + ((seg->span == 2) ? -1 : 0);
139 scm_i_clear_segment_mark_space (scm_t_heap_segment *seg)
141 scm_t_cell * markspace = seg->bounds[1];
143 memset (markspace, 0x00,
144 scm_i_segment_card_count (seg) * SCM_GC_CARD_BVEC_SIZE_IN_LONGS * SCM_SIZEOF_LONG);
148 Sweep cards from SEG until we've gathered THRESHOLD cells
155 scm_i_sweep_some_cards (scm_t_heap_segment *seg)
160 int (*sweeper) (scm_t_cell *, SCM *, scm_t_heap_segment* )
161 = (seg->first_time) ? &scm_i_init_card_freelist : &scm_i_sweep_card;
163 scm_t_cell * next_free = seg->next_free_card;
166 while (collected < threshold && next_free < seg->bounds[1])
168 collected += (*sweeper) (next_free, &cells, seg);
169 next_free += SCM_GC_CARD_N_CELLS;
173 scm_gc_cells_swept += cards_swept * (SCM_GC_CARD_N_CELLS - SCM_GC_CARD_N_HEADER_CELLS);
174 scm_gc_cells_collected += collected * seg->span;
176 if (!seg->first_time)
178 scm_gc_cells_allocated_acc +=
179 (scm_cells_allocated - scm_last_cells_allocated);
181 scm_cells_allocated -= collected * seg->span;
182 scm_last_cells_allocated = scm_cells_allocated;
184 seg->freelist->collected += collected * seg->span;
187 if(next_free == seg->bounds[1])
192 seg->next_free_card = next_free;
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
202 Implementation is slightly ugh.
204 FIXME: if you do scm_i_sweep_segment(), and then allocate from this
205 segment again, the statistics are off.
208 scm_i_sweep_segment (scm_t_heap_segment * seg)
210 scm_t_cell * p = seg->next_free_card;
211 int yield = scm_gc_cells_collected;
212 int coll = seg->freelist->collected;
213 unsigned long alloc = scm_cells_allocated ;
214 unsigned long last_alloc = scm_last_cells_allocated;
216 = scm_gc_cells_allocated_acc
217 + (alloc - last_alloc);
219 while (scm_i_sweep_some_cards (seg) != SCM_EOL)
222 scm_gc_cells_collected = yield;
227 scm_gc_cells_allocated_acc = last_total;
228 scm_cells_allocated = alloc;
229 scm_last_cells_allocated = alloc;
231 seg->freelist->collected = coll;
232 seg->next_free_card =p;
236 scm_i_sweep_all_segments (char const *reason)
240 for (i = 0; i < scm_i_heap_segment_table_size; i++)
242 scm_i_sweep_segment (scm_i_heap_segment_table[i]);
250 The table is sorted by the address of the data itself. This makes
251 for easy lookups. This is not portable: according to ANSI C,
252 pointers can only be compared within the same object (i.e. the same
253 block of malloced memory.). For machines with weird architectures,
254 this should be revised.
256 (Apparently, for this reason 1.6 and earlier had macros for pointer
259 perhaps it is worthwhile to remove the 2nd level of indirection in
260 the table, but this certainly makes for cleaner code.
262 scm_t_heap_segment ** scm_i_heap_segment_table;
263 size_t scm_i_heap_segment_table_size;
264 scm_t_cell *lowest_cell;
265 scm_t_cell *highest_cell;
269 scm_i_clear_mark_space (void)
272 for (; i < scm_i_heap_segment_table_size; i++)
274 scm_i_clear_segment_mark_space (scm_i_heap_segment_table[i]);
280 RETURN: index of inserted segment.
283 scm_i_insert_segment (scm_t_heap_segment * seg)
285 size_t size = (scm_i_heap_segment_table_size + 1) * sizeof (scm_t_heap_segment *);
286 SCM_SYSCALL(scm_i_heap_segment_table = ((scm_t_heap_segment **)
287 realloc ((char *)scm_i_heap_segment_table, size)));
290 We can't alloc 4 more bytes. This is hopeless.
292 if (!scm_i_heap_segment_table)
294 fprintf (stderr, "scm_i_get_new_heap_segment: Could not grow heap segment table.\n");
300 lowest_cell = seg->bounds[0];
301 highest_cell = seg->bounds[1];
305 lowest_cell = SCM_MIN (lowest_cell, seg->bounds[0]);
306 highest_cell = SCM_MAX (highest_cell, seg->bounds[1]);
314 while (i < scm_i_heap_segment_table_size
315 && scm_i_heap_segment_table[i]->bounds[0] <= seg->bounds[0])
319 We insert a new entry; if that happens to be before the
320 "current" segment of a freelist, we must move the freelist index
323 if (scm_i_master_freelist.heap_segment_idx >= i)
324 scm_i_master_freelist.heap_segment_idx ++;
325 if (scm_i_master_freelist2.heap_segment_idx >= i)
326 scm_i_master_freelist2.heap_segment_idx ++;
328 for (j = scm_i_heap_segment_table_size; j > i; --j)
329 scm_i_heap_segment_table[j] = scm_i_heap_segment_table[j - 1];
331 scm_i_heap_segment_table [i] = seg;
332 scm_i_heap_segment_table_size ++;
339 scm_i_sweep_some_segments (scm_t_cell_type_statistics * fl)
341 int i = fl->heap_segment_idx;
342 SCM collected = SCM_EOL;
348 i < scm_i_heap_segment_table_size; i++)
350 if (scm_i_heap_segment_table[i]->freelist != fl)
353 collected = scm_i_sweep_some_cards (scm_i_heap_segment_table[i]);
356 if (collected != SCM_EOL) /* Don't increment i */
360 fl->heap_segment_idx = i;
367 scm_i_reset_segments (void)
370 for (; i < scm_i_heap_segment_table_size; i++)
372 scm_t_heap_segment * seg = scm_i_heap_segment_table[i];
373 seg->next_free_card = seg->bounds[0];
378 Return a hashtab with counts of live objects, with tags as keys.
383 scm_i_all_segments_statistics (SCM tab)
386 for (; i < scm_i_heap_segment_table_size; i++)
388 scm_t_heap_segment * seg = scm_i_heap_segment_table[i];
389 scm_i_heap_segment_statistics (seg, tab);
399 Determine whether the given value does actually represent a cell in
400 some heap segment. If this is the case, the number of the heap
401 segment is returned. Otherwise, -1 is returned. Binary search is
402 used to determine the heap segment that contains the cell.
405 I think this function is too long to be inlined. --hwn
408 scm_i_find_heap_segment_containing_object (SCM obj)
413 if ((scm_t_cell* ) obj < lowest_cell || (scm_t_cell*) obj >= highest_cell)
418 scm_t_cell * ptr = SCM2PTR (obj);
419 unsigned long int i = 0;
420 unsigned long int j = scm_i_heap_segment_table_size - 1;
422 if (ptr < scm_i_heap_segment_table[i]->bounds[0])
424 else if (scm_i_heap_segment_table[j]->bounds[1] <= ptr)
430 if (ptr < scm_i_heap_segment_table[i]->bounds[1])
434 else if (scm_i_heap_segment_table[j]->bounds[0] <= ptr)
441 unsigned long int k = (i + j) / 2;
445 else if (ptr < scm_i_heap_segment_table[k]->bounds[1])
449 if (ptr < scm_i_heap_segment_table[i]->bounds[0])
452 else if (scm_i_heap_segment_table[k]->bounds[0] <= ptr)
456 if (scm_i_heap_segment_table[j]->bounds[1] <= ptr)
462 if (!SCM_DOUBLECELL_ALIGNED_P (obj) && scm_i_heap_segment_table[i]->span == 2)
464 else if (SCM_GC_IN_CARD_HEADERP (ptr))
474 Important entry point: try to grab some memory, and make it into a
477 RETURN: the index of the segment.
480 scm_i_get_new_heap_segment (scm_t_cell_type_statistics *freelist,
481 policy_on_error error_policy)
486 /* Assure that the new segment is predicted to be large enough.
488 * New yield should at least equal GC fraction of new heap size, i.e.
490 * y + dh > f * (h + dh)
493 * f : min yield fraction
495 * dh : size of new heap segment
497 * This gives dh > (f * h - y) / (1 - f)
499 float f = freelist->min_yield_fraction / 100.0;
500 float h = SCM_HEAP_SIZE;
502 = (f * h - scm_gc_cells_collected) / (1.0 - f);
504 /* Make heap grow with factor 1.5 */
505 len = freelist->heap_size / 2;
507 fprintf (stderr, "(%ld < %ld)", (long) len, (long) min_cells);
511 len = (unsigned long) min_cells;
512 len *= sizeof (scm_t_cell);
513 /* force new sampling */
514 freelist->collected = LONG_MAX;
517 if (len > scm_max_segment_size)
518 len = scm_max_segment_size;
519 if (len < SCM_MIN_HEAP_SEG_SIZE)
520 len = SCM_MIN_HEAP_SEG_SIZE;
523 scm_t_heap_segment * seg = scm_i_make_empty_heap_segment (freelist);
525 /* Allocate with decaying ambition. */
526 while (len >= SCM_MIN_HEAP_SEG_SIZE)
528 if (scm_i_initialize_heap_segment_data (seg, len))
530 return scm_i_insert_segment (seg);
537 if (error_policy == abort_on_error)
539 fprintf (stderr, "scm_i_get_new_heap_segment: Could not grow heap.\n");
546 scm_i_make_initial_segment (int init_heap_size, scm_t_cell_type_statistics *freelist)
548 scm_t_heap_segment * seg = scm_i_make_empty_heap_segment (freelist);
550 if (init_heap_size < 1)
552 init_heap_size = SCM_DEFAULT_INIT_HEAP_SIZE_1;
555 if (scm_i_initialize_heap_segment_data (seg, init_heap_size))
557 freelist->heap_segment_idx = scm_i_insert_segment (seg);
561 Why the fuck try twice? --hwn
565 scm_i_initialize_heap_segment_data (seg, SCM_HEAP_SEG_SIZE);
568 if (freelist->min_yield_fraction)
569 freelist->min_yield = (freelist->heap_size * freelist->min_yield_fraction