1 /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003, 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
18 /* #define DEBUGINFO */
29 #include "libguile/_scm.h"
30 #include "libguile/eval.h"
31 #include "libguile/stime.h"
32 #include "libguile/stackchk.h"
33 #include "libguile/struct.h"
34 #include "libguile/smob.h"
35 #include "libguile/unif.h"
36 #include "libguile/async.h"
37 #include "libguile/ports.h"
38 #include "libguile/root.h"
39 #include "libguile/strings.h"
40 #include "libguile/vectors.h"
41 #include "libguile/weaks.h"
42 #include "libguile/hashtab.h"
43 #include "libguile/tags.h"
45 #include "libguile/private-gc.h"
46 #include "libguile/validate.h"
47 #include "libguile/deprecation.h"
48 #include "libguile/gc.h"
49 #include "libguile/dynwind.h"
51 #ifdef GUILE_DEBUG_MALLOC
52 #include "libguile/debug-malloc.h"
63 /* Lock this mutex before doing lazy sweeping.
65 scm_i_pthread_mutex_t scm_i_sweep_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
67 /* Set this to != 0 if every cell that is accessed shall be checked:
69 int scm_debug_cell_accesses_p = 0;
70 int scm_expensive_debug_cell_accesses_p = 0;
72 /* Set this to 0 if no additional gc's shall be performed, otherwise set it to
73 * the number of cell accesses after which a gc shall be called.
75 int scm_debug_cells_gc_interval = 0;
78 Global variable, so you can switch it off at runtime by setting
79 scm_i_cell_validation_already_running.
81 int scm_i_cell_validation_already_running ;
83 #if (SCM_DEBUG_CELL_ACCESSES == 1)
88 Assert that the given object is a valid reference to a valid cell. This
89 test involves to determine whether the object is a cell pointer, whether
90 this pointer actually points into a heap segment and whether the cell
91 pointed to is not a free cell. Further, additional garbage collections may
92 get executed after a user defined number of cell accesses. This helps to
93 find places in the C code where references are dropped for extremely short
98 scm_i_expensive_validation_check (SCM cell)
100 if (!scm_in_heap_p (cell))
102 fprintf (stderr, "scm_assert_cell_valid: this object does not live in the heap: %lux\n",
103 (unsigned long) SCM_UNPACK (cell));
107 /* If desired, perform additional garbage collections after a user
108 * defined number of cell accesses.
110 if (scm_debug_cells_gc_interval)
112 static unsigned int counter = 0;
120 counter = scm_debug_cells_gc_interval;
127 scm_assert_cell_valid (SCM cell)
129 if (!scm_i_cell_validation_already_running && scm_debug_cell_accesses_p)
131 scm_i_cell_validation_already_running = 1; /* set to avoid recursion */
134 During GC, no user-code should be run, and the guile core
135 should use non-protected accessors.
137 if (scm_gc_running_p)
141 Only scm_in_heap_p and rescanning the heap is wildly
144 if (scm_expensive_debug_cell_accesses_p)
145 scm_i_expensive_validation_check (cell);
147 if (!SCM_GC_MARK_P (cell))
150 "scm_assert_cell_valid: this object is unmarked. \n"
151 "It has been garbage-collected in the last GC run: "
153 (unsigned long) SCM_UNPACK (cell));
157 scm_i_cell_validation_already_running = 0; /* re-enable */
163 SCM_DEFINE (scm_set_debug_cell_accesses_x, "set-debug-cell-accesses!", 1, 0, 0,
165 "If @var{flag} is @code{#f}, cell access checking is disabled.\n"
166 "If @var{flag} is @code{#t}, cheap cell access checking is enabled,\n"
167 "but no additional calls to garbage collection are issued.\n"
168 "If @var{flag} is a number, strict cell access checking is enabled,\n"
169 "with an additional garbage collection after the given\n"
170 "number of cell accesses.\n"
171 "This procedure only exists when the compile-time flag\n"
172 "@code{SCM_DEBUG_CELL_ACCESSES} was set to 1.")
173 #define FUNC_NAME s_scm_set_debug_cell_accesses_x
175 if (scm_is_false (flag))
177 scm_debug_cell_accesses_p = 0;
179 else if (scm_is_eq (flag, SCM_BOOL_T))
181 scm_debug_cells_gc_interval = 0;
182 scm_debug_cell_accesses_p = 1;
183 scm_expensive_debug_cell_accesses_p = 0;
187 scm_debug_cells_gc_interval = scm_to_signed_integer (flag, 0, INT_MAX);
188 scm_debug_cell_accesses_p = 1;
189 scm_expensive_debug_cell_accesses_p = 1;
191 return SCM_UNSPECIFIED;
196 #endif /* SCM_DEBUG_CELL_ACCESSES == 1 */
202 * is the number of bytes of malloc allocation needed to trigger gc.
204 unsigned long scm_mtrigger;
206 /* GC Statistics Keeping
208 unsigned long scm_cells_allocated = 0;
209 unsigned long scm_last_cells_allocated;
210 unsigned long scm_mallocated = 0;
211 unsigned long scm_gc_cells_collected;
212 unsigned long scm_gc_cells_collected_1 = 0; /* previous GC yield */
213 unsigned long scm_gc_malloc_collected;
214 unsigned long scm_gc_ports_collected;
215 unsigned long scm_gc_time_taken = 0;
216 static unsigned long t_before_gc;
217 unsigned long scm_gc_mark_time_taken = 0;
218 unsigned long scm_gc_times = 0;
219 unsigned long scm_gc_cells_swept = 0;
220 double scm_gc_cells_marked_acc = 0.;
221 double scm_gc_cells_swept_acc = 0.;
222 double scm_gc_cells_allocated_acc = 0.;
223 int scm_gc_cell_yield_percentage =0;
224 int scm_gc_malloc_yield_percentage = 0;
225 unsigned long protected_obj_count = 0;
228 SCM_SYMBOL (sym_cells_allocated, "cells-allocated");
229 SCM_SYMBOL (sym_heap_size, "cell-heap-size");
230 SCM_SYMBOL (sym_mallocated, "bytes-malloced");
231 SCM_SYMBOL (sym_mtrigger, "gc-malloc-threshold");
232 SCM_SYMBOL (sym_heap_segments, "cell-heap-segments");
233 SCM_SYMBOL (sym_gc_time_taken, "gc-time-taken");
234 SCM_SYMBOL (sym_gc_mark_time_taken, "gc-mark-time-taken");
235 SCM_SYMBOL (sym_times, "gc-times");
236 SCM_SYMBOL (sym_cells_marked, "cells-marked");
237 SCM_SYMBOL (sym_cells_swept, "cells-swept");
238 SCM_SYMBOL (sym_malloc_yield, "malloc-yield");
239 SCM_SYMBOL (sym_cell_yield, "cell-yield");
240 SCM_SYMBOL (sym_protected_objects, "protected-objects");
241 SCM_SYMBOL (sym_total_cells_allocated, "total-cells-allocated");
246 /* Number of calls to SCM_NEWCELL since startup. */
247 unsigned scm_newcell_count;
248 unsigned scm_newcell2_count;
251 /* {Scheme Interface to GC}
254 tag_table_to_type_alist (void *closure, SCM key, SCM val, SCM acc)
256 if (scm_is_integer (key))
258 int c_tag = scm_to_int (key);
260 char const * name = scm_i_tag_name (c_tag);
263 key = scm_from_locale_string (name);
268 sprintf (s, "tag %d", c_tag);
269 key = scm_from_locale_string (s);
273 return scm_cons (scm_cons (key, val), acc);
276 SCM_DEFINE (scm_gc_live_object_stats, "gc-live-object-stats", 0, 0, 0,
278 "Return an alist of statistics of the current live objects. ")
279 #define FUNC_NAME s_scm_gc_live_object_stats
281 SCM tab = scm_make_hash_table (scm_from_int (57));
284 scm_i_all_segments_statistics (tab);
287 = scm_internal_hash_fold (&tag_table_to_type_alist, NULL, SCM_EOL, tab);
293 extern int scm_gc_malloc_yield_percentage;
294 SCM_DEFINE (scm_gc_stats, "gc-stats", 0, 0, 0,
296 "Return an association list of statistics about Guile's current\n"
298 #define FUNC_NAME s_scm_gc_stats
301 SCM heap_segs = SCM_EOL ;
302 unsigned long int local_scm_mtrigger;
303 unsigned long int local_scm_mallocated;
304 unsigned long int local_scm_heap_size;
305 int local_scm_gc_cell_yield_percentage;
306 int local_scm_gc_malloc_yield_percentage;
307 unsigned long int local_scm_cells_allocated;
308 unsigned long int local_scm_gc_time_taken;
309 unsigned long int local_scm_gc_times;
310 unsigned long int local_scm_gc_mark_time_taken;
311 unsigned long int local_protected_obj_count;
312 double local_scm_gc_cells_swept;
313 double local_scm_gc_cells_marked;
314 double local_scm_total_cells_allocated;
316 unsigned long *bounds = 0;
317 int table_size = scm_i_heap_segment_table_size;
318 SCM_CRITICAL_SECTION_START;
321 temporarily store the numbers, so as not to cause GC.
324 bounds = malloc (sizeof (unsigned long) * table_size * 2);
327 for (i = table_size; i--; )
329 bounds[2*i] = (unsigned long)scm_i_heap_segment_table[i]->bounds[0];
330 bounds[2*i+1] = (unsigned long)scm_i_heap_segment_table[i]->bounds[1];
334 /* Below, we cons to produce the resulting list. We want a snapshot of
335 * the heap situation before consing.
337 local_scm_mtrigger = scm_mtrigger;
338 local_scm_mallocated = scm_mallocated;
339 local_scm_heap_size = SCM_HEAP_SIZE;
341 local_scm_cells_allocated = scm_cells_allocated;
343 local_scm_gc_time_taken = scm_gc_time_taken;
344 local_scm_gc_mark_time_taken = scm_gc_mark_time_taken;
345 local_scm_gc_times = scm_gc_times;
346 local_scm_gc_malloc_yield_percentage = scm_gc_malloc_yield_percentage;
347 local_scm_gc_cell_yield_percentage= scm_gc_cell_yield_percentage;
348 local_protected_obj_count = protected_obj_count;
349 local_scm_gc_cells_swept =
350 (double) scm_gc_cells_swept_acc
351 + (double) scm_gc_cells_swept;
352 local_scm_gc_cells_marked = scm_gc_cells_marked_acc
353 +(double) scm_gc_cells_swept
354 -(double) scm_gc_cells_collected;
356 local_scm_total_cells_allocated = scm_gc_cells_allocated_acc
357 + (double) (scm_cells_allocated - scm_last_cells_allocated);
359 for (i = table_size; i--;)
361 heap_segs = scm_cons (scm_cons (scm_from_ulong (bounds[2*i]),
362 scm_from_ulong (bounds[2*i+1])),
365 /* njrev: can any of these scm_cons's or scm_list_n signal a memory
366 error? If so we need a frame here. */
368 scm_list_n (scm_cons (sym_gc_time_taken,
369 scm_from_ulong (local_scm_gc_time_taken)),
370 scm_cons (sym_cells_allocated,
371 scm_from_ulong (local_scm_cells_allocated)),
372 scm_cons (sym_total_cells_allocated,
373 scm_from_ulong (local_scm_total_cells_allocated)),
374 scm_cons (sym_heap_size,
375 scm_from_ulong (local_scm_heap_size)),
376 scm_cons (sym_mallocated,
377 scm_from_ulong (local_scm_mallocated)),
378 scm_cons (sym_mtrigger,
379 scm_from_ulong (local_scm_mtrigger)),
381 scm_from_ulong (local_scm_gc_times)),
382 scm_cons (sym_gc_mark_time_taken,
383 scm_from_ulong (local_scm_gc_mark_time_taken)),
384 scm_cons (sym_cells_marked,
385 scm_from_double (local_scm_gc_cells_marked)),
386 scm_cons (sym_cells_swept,
387 scm_from_double (local_scm_gc_cells_swept)),
388 scm_cons (sym_malloc_yield,
389 scm_from_long(local_scm_gc_malloc_yield_percentage)),
390 scm_cons (sym_cell_yield,
391 scm_from_long (local_scm_gc_cell_yield_percentage)),
392 scm_cons (sym_protected_objects,
393 scm_from_ulong (local_protected_obj_count)),
394 scm_cons (sym_heap_segments, heap_segs),
396 SCM_CRITICAL_SECTION_END;
404 gc_start_stats (const char *what SCM_UNUSED)
406 t_before_gc = scm_c_get_internal_run_time ();
408 scm_gc_cells_marked_acc += (double) scm_gc_cells_swept
409 - (double) scm_gc_cells_collected;
410 scm_gc_cells_swept_acc += (double) scm_gc_cells_swept;
412 scm_gc_cell_yield_percentage = ( scm_gc_cells_collected * 100 ) / SCM_HEAP_SIZE;
414 scm_gc_cells_swept = 0;
415 scm_gc_cells_collected_1 = scm_gc_cells_collected;
418 CELLS SWEPT is another word for the number of cells that were
419 examined during GC. YIELD is the number that we cleaned
420 out. MARKED is the number that weren't cleaned.
422 scm_gc_cells_collected = 0;
423 scm_gc_malloc_collected = 0;
424 scm_gc_ports_collected = 0;
430 unsigned long t = scm_c_get_internal_run_time ();
431 scm_gc_time_taken += (t - t_before_gc);
437 SCM_DEFINE (scm_object_address, "object-address", 1, 0, 0,
439 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
440 "returned by this function for @var{obj}")
441 #define FUNC_NAME s_scm_object_address
443 return scm_from_ulong (SCM_UNPACK (obj));
448 SCM_DEFINE (scm_gc, "gc", 0, 0, 0,
450 "Scans all of SCM objects and reclaims for further use those that are\n"
451 "no longer accessible.")
452 #define FUNC_NAME s_scm_gc
454 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex);
455 scm_gc_running_p = 1;
457 /* njrev: It looks as though other places, e.g. scm_realloc,
458 can call scm_i_gc without acquiring the sweep mutex. Does this
459 matter? Also scm_i_gc (or its descendants) touch the
460 scm_sys_protects, which are protected in some cases
461 (e.g. scm_permobjs above in scm_gc_stats) by a critical section,
462 not by the sweep mutex. Shouldn't all the GC-relevant objects be
463 protected in the same way? */
464 scm_gc_running_p = 0;
465 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex);
466 scm_c_hook_run (&scm_after_gc_c_hook, 0);
467 return SCM_UNSPECIFIED;
474 /* The master is global and common while the freelist will be
475 * individual for each thread.
479 scm_gc_for_newcell (scm_t_cell_type_statistics *freelist, SCM *free_cells)
484 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex);
485 scm_gc_running_p = 1;
487 *free_cells = scm_i_sweep_some_segments (freelist);
488 if (*free_cells == SCM_EOL && scm_i_gc_grow_heap_p (freelist))
490 freelist->heap_segment_idx = scm_i_get_new_heap_segment (freelist, abort_on_error);
491 *free_cells = scm_i_sweep_some_segments (freelist);
494 if (*free_cells == SCM_EOL)
497 with the advent of lazy sweep, GC yield is only known just
500 scm_i_adjust_min_yield (freelist);
503 out of fresh cells. Try to get some new ones.
509 *free_cells = scm_i_sweep_some_segments (freelist);
512 if (*free_cells == SCM_EOL)
515 failed getting new cells. Get new juice or die.
517 freelist->heap_segment_idx = scm_i_get_new_heap_segment (freelist, abort_on_error);
518 *free_cells = scm_i_sweep_some_segments (freelist);
521 if (*free_cells == SCM_EOL)
526 *free_cells = SCM_FREE_CELL_CDR (cell);
528 scm_gc_running_p = 0;
529 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex);
532 scm_c_hook_run (&scm_after_gc_c_hook, 0);
538 scm_t_c_hook scm_before_gc_c_hook;
539 scm_t_c_hook scm_before_mark_c_hook;
540 scm_t_c_hook scm_before_sweep_c_hook;
541 scm_t_c_hook scm_after_sweep_c_hook;
542 scm_t_c_hook scm_after_gc_c_hook;
544 /* Must be called while holding scm_i_sweep_mutex.
548 scm_i_gc (const char *what)
550 scm_i_thread_put_to_sleep ();
552 scm_c_hook_run (&scm_before_gc_c_hook, 0);
555 fprintf (stderr,"gc reason %s\n", what);
558 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist))
560 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2)) ? "o" : "m"));
563 gc_start_stats (what);
566 Set freelists to NULL so scm_cons() always triggers gc, causing
567 the assertion above to fail.
569 *SCM_FREELIST_LOC (scm_i_freelist) = SCM_EOL;
570 *SCM_FREELIST_LOC (scm_i_freelist2) = SCM_EOL;
573 Let's finish the sweep. The conservative GC might point into the
574 garbage, and marking that would create a mess.
576 scm_i_sweep_all_segments("GC");
577 if (scm_mallocated < scm_i_deprecated_memory_return)
579 /* The byte count of allocated objects has underflowed. This is
580 probably because you forgot to report the sizes of objects you
581 have allocated, by calling scm_done_malloc or some such. When
582 the GC freed them, it subtracted their size from
583 scm_mallocated, which underflowed. */
585 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
586 "This is probably because the GC hasn't been correctly informed\n"
587 "about object sizes\n");
590 scm_mallocated -= scm_i_deprecated_memory_return;
595 scm_c_hook_run (&scm_before_mark_c_hook, 0);
597 scm_gc_mark_time_taken += (scm_c_get_internal_run_time () - t_before_gc);
601 TODO: the after_sweep hook should probably be moved to just before
602 the mark, since that's where the sweep is finished in lazy
605 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
606 original meaning implied at least two things: that it would be
609 1. the freelist is re-initialized (no evaluation possible, though)
613 2. the heap is "fresh"
614 (it is well-defined what data is used and what is not)
616 Neither of these conditions would hold just before the mark phase.
618 Of course, the lazy sweeping has muddled the distinction between
619 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
620 there were no difference, it would still be useful to have two
621 distinct classes of hook functions since this can prevent some
622 bad interference when several modules adds gc hooks.
625 scm_c_hook_run (&scm_before_sweep_c_hook, 0);
627 scm_c_hook_run (&scm_after_sweep_c_hook, 0);
631 scm_i_thread_wake_up ();
634 For debugging purposes, you could do
635 scm_i_sweep_all_segments("debug"), but then the remains of the
636 cell aren't left to analyse.
641 /* {GC Protection Helper Functions}
646 * If within a function you need to protect one or more scheme objects from
647 * garbage collection, pass them as parameters to one of the
648 * scm_remember_upto_here* functions below. These functions don't do
649 * anything, but since the compiler does not know that they are actually
650 * no-ops, it will generate code that calls these functions with the given
651 * parameters. Therefore, you can be sure that the compiler will keep those
652 * scheme values alive (on the stack or in a register) up to the point where
653 * scm_remember_upto_here* is called. In other words, place the call to
654 * scm_remember_upto_here* _behind_ the last code in your function, that
655 * depends on the scheme object to exist.
657 * Example: We want to make sure that the string object str does not get
658 * garbage collected during the execution of 'some_function' in the code
659 * below, because otherwise the characters belonging to str would be freed and
660 * 'some_function' might access freed memory. To make sure that the compiler
661 * keeps str alive on the stack or in a register such that it is visible to
662 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
663 * call to 'some_function'. Note that this would not be necessary if str was
664 * used anyway after the call to 'some_function'.
665 * char *chars = scm_i_string_chars (str);
666 * some_function (chars);
667 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
670 /* Remove any macro versions of these while defining the functions.
671 Functions are always included in the library, for upward binary
672 compatibility and in case combinations of GCC and non-GCC are used. */
673 #undef scm_remember_upto_here_1
674 #undef scm_remember_upto_here_2
677 scm_remember_upto_here_1 (SCM obj SCM_UNUSED)
679 /* Empty. Protects a single object from garbage collection. */
683 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED, SCM obj2 SCM_UNUSED)
685 /* Empty. Protects two objects from garbage collection. */
689 scm_remember_upto_here (SCM obj SCM_UNUSED, ...)
691 /* Empty. Protects any number of objects from garbage collection. */
695 These crazy functions prevent garbage collection
696 of arguments after the first argument by
697 ensuring they remain live throughout the
698 function because they are used in the last
699 line of the code block.
700 It'd be better to have a nice compiler hint to
701 aid the conservative stack-scanning GC. --03/09/00 gjb */
703 scm_return_first (SCM elt, ...)
709 scm_return_first_int (int i, ...)
716 scm_permanent_object (SCM obj)
718 SCM cell = scm_cons (obj, SCM_EOL);
719 SCM_CRITICAL_SECTION_START;
720 SCM_SETCDR (cell, scm_permobjs);
722 SCM_CRITICAL_SECTION_END;
727 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
728 other references are dropped, until the object is unprotected by calling
729 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
730 i. e. it is possible to protect the same object several times, but it is
731 necessary to unprotect the object the same number of times to actually get
732 the object unprotected. It is an error to unprotect an object more often
733 than it has been protected before. The function scm_protect_object returns
737 /* Implementation note: For every object X, there is a counter which
738 scm_gc_protect_object(X) increments and scm_gc_unprotect_object(X) decrements.
744 scm_gc_protect_object (SCM obj)
748 /* This critical section barrier will be replaced by a mutex. */
749 /* njrev: Indeed; if my comment above is correct, there is the same
750 critsec/mutex inconsistency here. */
751 SCM_CRITICAL_SECTION_START;
753 handle = scm_hashq_create_handle_x (scm_protects, obj, scm_from_int (0));
754 SCM_SETCDR (handle, scm_sum (SCM_CDR (handle), scm_from_int (1)));
756 protected_obj_count ++;
758 SCM_CRITICAL_SECTION_END;
764 /* Remove any protection for OBJ established by a prior call to
765 scm_protect_object. This function returns OBJ.
767 See scm_protect_object for more information. */
769 scm_gc_unprotect_object (SCM obj)
773 /* This critical section barrier will be replaced by a mutex. */
774 /* njrev: and again. */
775 SCM_CRITICAL_SECTION_START;
777 if (scm_gc_running_p)
779 fprintf (stderr, "scm_unprotect_object called during GC.\n");
783 handle = scm_hashq_get_handle (scm_protects, obj);
785 if (scm_is_false (handle))
787 fprintf (stderr, "scm_unprotect_object called on unprotected object\n");
792 SCM count = scm_difference (SCM_CDR (handle), scm_from_int (1));
793 if (scm_is_eq (count, scm_from_int (0)))
794 scm_hashq_remove_x (scm_protects, obj);
796 SCM_SETCDR (handle, count);
798 protected_obj_count --;
800 SCM_CRITICAL_SECTION_END;
806 scm_gc_register_root (SCM *p)
809 SCM key = scm_from_ulong ((unsigned long) p);
811 /* This critical section barrier will be replaced by a mutex. */
812 /* njrev: and again. */
813 SCM_CRITICAL_SECTION_START;
815 handle = scm_hashv_create_handle_x (scm_gc_registered_roots, key,
817 /* njrev: note also that the above can probably signal an error */
818 SCM_SETCDR (handle, scm_sum (SCM_CDR (handle), scm_from_int (1)));
820 SCM_CRITICAL_SECTION_END;
824 scm_gc_unregister_root (SCM *p)
827 SCM key = scm_from_ulong ((unsigned long) p);
829 /* This critical section barrier will be replaced by a mutex. */
830 /* njrev: and again. */
831 SCM_CRITICAL_SECTION_START;
833 handle = scm_hashv_get_handle (scm_gc_registered_roots, key);
835 if (scm_is_false (handle))
837 fprintf (stderr, "scm_gc_unregister_root called on unregistered root\n");
842 SCM count = scm_difference (SCM_CDR (handle), scm_from_int (1));
843 if (scm_is_eq (count, scm_from_int (0)))
844 scm_hashv_remove_x (scm_gc_registered_roots, key);
846 SCM_SETCDR (handle, count);
849 SCM_CRITICAL_SECTION_END;
853 scm_gc_register_roots (SCM *b, unsigned long n)
856 for (; p < b + n; ++p)
857 scm_gc_register_root (p);
861 scm_gc_unregister_roots (SCM *b, unsigned long n)
864 for (; p < b + n; ++p)
865 scm_gc_unregister_root (p);
868 int scm_i_terminating;
874 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
877 /* Get an integer from an environment variable. */
879 scm_getenv_int (const char *var, int def)
882 char *val = getenv (var);
886 res = strtol (val, &end, 10);
893 scm_storage_prehistory ()
895 scm_c_hook_init (&scm_before_gc_c_hook, 0, SCM_C_HOOK_NORMAL);
896 scm_c_hook_init (&scm_before_mark_c_hook, 0, SCM_C_HOOK_NORMAL);
897 scm_c_hook_init (&scm_before_sweep_c_hook, 0, SCM_C_HOOK_NORMAL);
898 scm_c_hook_init (&scm_after_sweep_c_hook, 0, SCM_C_HOOK_NORMAL);
899 scm_c_hook_init (&scm_after_gc_c_hook, 0, SCM_C_HOOK_NORMAL);
902 scm_i_pthread_mutex_t scm_i_gc_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
909 j = SCM_NUM_PROTECTS;
911 scm_sys_protects[--j] = SCM_BOOL_F;
913 scm_gc_init_freelist();
914 scm_gc_init_malloc ();
916 j = SCM_HEAP_SEG_SIZE;
919 /* Initialise the list of ports. */
920 scm_i_port_table = (scm_t_port **)
921 malloc (sizeof (scm_t_port *) * scm_i_port_table_room);
922 if (!scm_i_port_table)
926 /* We can't have a cleanup handler since we have no thread to run it
933 on_exit (cleanup, 0);
939 scm_stand_in_procs = scm_make_weak_key_hash_table (scm_from_int (257));
940 scm_permobjs = SCM_EOL;
941 scm_protects = scm_c_make_hash_table (31);
942 scm_gc_registered_roots = scm_c_make_hash_table (31);
949 SCM scm_after_gc_hook;
953 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
954 * is run after the gc, as soon as the asynchronous events are handled by the
958 gc_async_thunk (void)
960 scm_c_run_hook (scm_after_gc_hook, SCM_EOL);
961 return SCM_UNSPECIFIED;
965 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
966 * the garbage collection. The only purpose of this function is to mark the
967 * gc_async (which will eventually lead to the execution of the
971 mark_gc_async (void * hook_data SCM_UNUSED,
972 void *fn_data SCM_UNUSED,
973 void *data SCM_UNUSED)
975 /* If cell access debugging is enabled, the user may choose to perform
976 * additional garbage collections after an arbitrary number of cell
977 * accesses. We don't want the scheme level after-gc-hook to be performed
978 * for each of these garbage collections for the following reason: The
979 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
980 * after-gc-hook was performed with every gc, and if the gc was performed
981 * after a very small number of cell accesses, then the number of cell
982 * accesses during the execution of the after-gc-hook will suffice to cause
983 * the execution of the next gc. Then, guile would keep executing the
984 * after-gc-hook over and over again, and would never come to do other
987 * To overcome this problem, if cell access debugging with additional
988 * garbage collections is enabled, the after-gc-hook is never run by the
989 * garbage collecter. When running guile with cell access debugging and the
990 * execution of the after-gc-hook is desired, then it is necessary to run
991 * the hook explicitly from the user code. This has the effect, that from
992 * the scheme level point of view it seems that garbage collection is
993 * performed with a much lower frequency than it actually is. Obviously,
994 * this will not work for code that depends on a fixed one to one
995 * relationship between the execution counts of the C level garbage
996 * collection hooks and the execution count of the scheme level
1000 #if (SCM_DEBUG_CELL_ACCESSES == 1)
1001 if (scm_debug_cells_gc_interval == 0)
1002 scm_system_async_mark (gc_async);
1004 scm_system_async_mark (gc_async);
1013 scm_gc_init_mark ();
1015 scm_after_gc_hook = scm_permanent_object (scm_make_hook (SCM_INUM0));
1016 scm_c_define ("after-gc-hook", scm_after_gc_hook);
1018 gc_async = scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0,
1021 scm_c_hook_add (&scm_after_gc_c_hook, mark_gc_async, NULL, 0);
1023 #include "libguile/gc.x"
1028 # include <sys/param.h>
1029 # include <sys/pstat.h>
1031 scm_ia64_register_backing_store_base (void)
1033 struct pst_vm_status vm_status;
1035 while (pstat_getprocvm (&vm_status, sizeof (vm_status), 0, i++) == 1)
1036 if (vm_status.pst_type == PS_RSESTACK)
1037 return (void *) vm_status.pst_vaddr;
1041 scm_ia64_ar_bsp (const void *ctx)
1044 __uc_get_ar_bsp(ctx, &bsp);
1045 return (void *) bsp;
1049 # include <ucontext.h>
1051 scm_ia64_register_backing_store_base (void)
1053 extern void *__libc_ia64_register_backing_store_base;
1054 return __libc_ia64_register_backing_store_base;
1057 scm_ia64_ar_bsp (const void *opaque)
1059 const ucontext_t *ctx = opaque;
1060 return (void *) ctx->uc_mcontext.sc_ar_bsp;
1063 #endif /* __ia64__ */
1067 #define FUNC_NAME "scm_gc_sweep"
1069 scm_i_deprecated_memory_return = 0;
1071 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist);
1072 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2);
1075 NOTHING HERE: LAZY SWEEPING !
1077 scm_i_reset_segments ();
1079 *SCM_FREELIST_LOC (scm_i_freelist) = SCM_EOL;
1080 *SCM_FREELIST_LOC (scm_i_freelist2) = SCM_EOL;
1082 /* Invalidate the freelists of other threads. */
1083 scm_i_thread_invalidate_freelists ();