1 /* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2003 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 /* #define DEBUGINFO */
33 extern unsigned long * __libc_ia64_register_backing_store_base
;
36 #include "libguile/_scm.h"
37 #include "libguile/eval.h"
38 #include "libguile/stime.h"
39 #include "libguile/stackchk.h"
40 #include "libguile/struct.h"
41 #include "libguile/smob.h"
42 #include "libguile/unif.h"
43 #include "libguile/async.h"
44 #include "libguile/ports.h"
45 #include "libguile/root.h"
46 #include "libguile/strings.h"
47 #include "libguile/vectors.h"
48 #include "libguile/weaks.h"
49 #include "libguile/hashtab.h"
50 #include "libguile/tags.h"
52 #include "libguile/private-gc.h"
53 #include "libguile/validate.h"
54 #include "libguile/deprecation.h"
55 #include "libguile/gc.h"
56 #include "libguile/dynwind.h"
58 #ifdef GUILE_DEBUG_MALLOC
59 #include "libguile/debug-malloc.h"
70 /* Lock this mutex before doing lazy sweeping.
72 scm_i_pthread_mutex_t scm_i_sweep_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
74 /* Set this to != 0 if every cell that is accessed shall be checked:
76 int scm_debug_cell_accesses_p
= 0;
77 int scm_expensive_debug_cell_accesses_p
= 0;
79 /* Set this to 0 if no additional gc's shall be performed, otherwise set it to
80 * the number of cell accesses after which a gc shall be called.
82 int scm_debug_cells_gc_interval
= 0;
85 Global variable, so you can switch it off at runtime by setting
86 scm_i_cell_validation_already_running.
88 int scm_i_cell_validation_already_running
;
90 #if (SCM_DEBUG_CELL_ACCESSES == 1)
95 Assert that the given object is a valid reference to a valid cell. This
96 test involves to determine whether the object is a cell pointer, whether
97 this pointer actually points into a heap segment and whether the cell
98 pointed to is not a free cell. Further, additional garbage collections may
99 get executed after a user defined number of cell accesses. This helps to
100 find places in the C code where references are dropped for extremely short
105 scm_i_expensive_validation_check (SCM cell
)
107 if (!scm_in_heap_p (cell
))
109 fprintf (stderr
, "scm_assert_cell_valid: this object does not live in the heap: %lux\n",
110 (unsigned long) SCM_UNPACK (cell
));
114 /* If desired, perform additional garbage collections after a user
115 * defined number of cell accesses.
117 if (scm_debug_cells_gc_interval
)
119 static unsigned int counter
= 0;
127 counter
= scm_debug_cells_gc_interval
;
134 scm_assert_cell_valid (SCM cell
)
136 if (!scm_i_cell_validation_already_running
&& scm_debug_cell_accesses_p
)
138 scm_i_cell_validation_already_running
= 1; /* set to avoid recursion */
141 During GC, no user-code should be run, and the guile core
142 should use non-protected accessors.
144 if (scm_gc_running_p
)
148 Only scm_in_heap_p and rescanning the heap is wildly
151 if (scm_expensive_debug_cell_accesses_p
)
152 scm_i_expensive_validation_check (cell
);
154 if (!SCM_GC_MARK_P (cell
))
157 "scm_assert_cell_valid: this object is unmarked. \n"
158 "It has been garbage-collected in the last GC run: "
160 (unsigned long) SCM_UNPACK (cell
));
164 scm_i_cell_validation_already_running
= 0; /* re-enable */
170 SCM_DEFINE (scm_set_debug_cell_accesses_x
, "set-debug-cell-accesses!", 1, 0, 0,
172 "If @var{flag} is @code{#f}, cell access checking is disabled.\n"
173 "If @var{flag} is @code{#t}, cheap cell access checking is enabled,\n"
174 "but no additional calls to garbage collection are issued.\n"
175 "If @var{flag} is a number, strict cell access checking is enabled,\n"
176 "with an additional garbage collection after the given\n"
177 "number of cell accesses.\n"
178 "This procedure only exists when the compile-time flag\n"
179 "@code{SCM_DEBUG_CELL_ACCESSES} was set to 1.")
180 #define FUNC_NAME s_scm_set_debug_cell_accesses_x
182 if (scm_is_false (flag
))
184 scm_debug_cell_accesses_p
= 0;
186 else if (scm_is_eq (flag
, SCM_BOOL_T
))
188 scm_debug_cells_gc_interval
= 0;
189 scm_debug_cell_accesses_p
= 1;
190 scm_expensive_debug_cell_accesses_p
= 0;
194 scm_debug_cells_gc_interval
= scm_to_signed_integer (flag
, 0, INT_MAX
);
195 scm_debug_cell_accesses_p
= 1;
196 scm_expensive_debug_cell_accesses_p
= 1;
198 return SCM_UNSPECIFIED
;
203 #endif /* SCM_DEBUG_CELL_ACCESSES == 1 */
209 * is the number of bytes of malloc allocation needed to trigger gc.
211 unsigned long scm_mtrigger
;
213 /* During collection, this accumulates objects holding
216 SCM scm_weak_vectors
;
218 /* GC Statistics Keeping
220 unsigned long scm_cells_allocated
= 0;
221 unsigned long scm_mallocated
= 0;
222 unsigned long scm_gc_cells_collected
;
223 unsigned long scm_gc_cells_collected_1
= 0; /* previous GC yield */
224 unsigned long scm_gc_malloc_collected
;
225 unsigned long scm_gc_ports_collected
;
226 unsigned long scm_gc_time_taken
= 0;
227 static unsigned long t_before_gc
;
228 unsigned long scm_gc_mark_time_taken
= 0;
229 unsigned long scm_gc_times
= 0;
230 unsigned long scm_gc_cells_swept
= 0;
231 double scm_gc_cells_marked_acc
= 0.;
232 double scm_gc_cells_swept_acc
= 0.;
233 int scm_gc_cell_yield_percentage
=0;
234 int scm_gc_malloc_yield_percentage
= 0;
235 unsigned long protected_obj_count
= 0;
238 SCM_SYMBOL (sym_cells_allocated
, "cells-allocated");
239 SCM_SYMBOL (sym_heap_size
, "cell-heap-size");
240 SCM_SYMBOL (sym_mallocated
, "bytes-malloced");
241 SCM_SYMBOL (sym_mtrigger
, "gc-malloc-threshold");
242 SCM_SYMBOL (sym_heap_segments
, "cell-heap-segments");
243 SCM_SYMBOL (sym_gc_time_taken
, "gc-time-taken");
244 SCM_SYMBOL (sym_gc_mark_time_taken
, "gc-mark-time-taken");
245 SCM_SYMBOL (sym_times
, "gc-times");
246 SCM_SYMBOL (sym_cells_marked
, "cells-marked");
247 SCM_SYMBOL (sym_cells_swept
, "cells-swept");
248 SCM_SYMBOL (sym_malloc_yield
, "malloc-yield");
249 SCM_SYMBOL (sym_cell_yield
, "cell-yield");
250 SCM_SYMBOL (sym_protected_objects
, "protected-objects");
255 /* Number of calls to SCM_NEWCELL since startup. */
256 unsigned scm_newcell_count
;
257 unsigned scm_newcell2_count
;
260 /* {Scheme Interface to GC}
263 tag_table_to_type_alist (void *closure
, SCM key
, SCM val
, SCM acc
)
265 scm_t_bits c_tag
= scm_to_int (key
);
267 char const * name
= scm_i_tag_name (c_tag
);
269 key
= scm_from_locale_string (name
);
271 return scm_cons (scm_cons (key
, val
), acc
);
274 SCM_DEFINE (scm_gc_live_object_stats
, "gc-live-object-stats", 0, 0, 0,
276 "Return an alist of statistics of the current live objects. ")
277 #define FUNC_NAME s_scm_gc_live_object_stats
279 SCM tab
= scm_make_hash_table (scm_from_int (57));
280 scm_i_all_segments_statistics (tab
);
283 = scm_internal_hash_fold (&tag_table_to_type_alist
, NULL
, SCM_EOL
, tab
);
289 extern int scm_gc_malloc_yield_percentage
;
290 SCM_DEFINE (scm_gc_stats
, "gc-stats", 0, 0, 0,
292 "Return an association list of statistics about Guile's current\n"
294 #define FUNC_NAME s_scm_gc_stats
297 SCM heap_segs
= SCM_EOL
;
298 unsigned long int local_scm_mtrigger
;
299 unsigned long int local_scm_mallocated
;
300 unsigned long int local_scm_heap_size
;
301 int local_scm_gc_cell_yield_percentage
;
302 int local_scm_gc_malloc_yield_percentage
;
303 unsigned long int local_scm_cells_allocated
;
304 unsigned long int local_scm_gc_time_taken
;
305 unsigned long int local_scm_gc_times
;
306 unsigned long int local_scm_gc_mark_time_taken
;
307 unsigned long int local_protected_obj_count
;
308 double local_scm_gc_cells_swept
;
309 double local_scm_gc_cells_marked
;
311 unsigned long *bounds
= 0;
312 int table_size
= scm_i_heap_segment_table_size
;
313 SCM_CRITICAL_SECTION_START
;
316 temporarily store the numbers, so as not to cause GC.
319 bounds
= malloc (sizeof (int) * table_size
* 2);
322 for (i
= table_size
; i
--; )
324 bounds
[2*i
] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[0];
325 bounds
[2*i
+1] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[1];
329 /* Below, we cons to produce the resulting list. We want a snapshot of
330 * the heap situation before consing.
332 local_scm_mtrigger
= scm_mtrigger
;
333 local_scm_mallocated
= scm_mallocated
;
334 local_scm_heap_size
= SCM_HEAP_SIZE
;
336 local_scm_cells_allocated
= scm_cells_allocated
;
338 local_scm_gc_time_taken
= scm_gc_time_taken
;
339 local_scm_gc_mark_time_taken
= scm_gc_mark_time_taken
;
340 local_scm_gc_times
= scm_gc_times
;
341 local_scm_gc_malloc_yield_percentage
= scm_gc_malloc_yield_percentage
;
342 local_scm_gc_cell_yield_percentage
= scm_gc_cell_yield_percentage
;
343 local_protected_obj_count
= protected_obj_count
;
344 local_scm_gc_cells_swept
=
345 (double) scm_gc_cells_swept_acc
346 + (double) scm_gc_cells_swept
;
347 local_scm_gc_cells_marked
= scm_gc_cells_marked_acc
348 +(double) scm_gc_cells_swept
349 -(double) scm_gc_cells_collected
;
351 for (i
= table_size
; i
--;)
353 heap_segs
= scm_cons (scm_cons (scm_from_ulong (bounds
[2*i
]),
354 scm_from_ulong (bounds
[2*i
+1])),
359 scm_list_n (scm_cons (sym_gc_time_taken
,
360 scm_from_ulong (local_scm_gc_time_taken
)),
361 scm_cons (sym_cells_allocated
,
362 scm_from_ulong (local_scm_cells_allocated
)),
363 scm_cons (sym_heap_size
,
364 scm_from_ulong (local_scm_heap_size
)),
365 scm_cons (sym_mallocated
,
366 scm_from_ulong (local_scm_mallocated
)),
367 scm_cons (sym_mtrigger
,
368 scm_from_ulong (local_scm_mtrigger
)),
370 scm_from_ulong (local_scm_gc_times
)),
371 scm_cons (sym_gc_mark_time_taken
,
372 scm_from_ulong (local_scm_gc_mark_time_taken
)),
373 scm_cons (sym_cells_marked
,
374 scm_from_double (local_scm_gc_cells_marked
)),
375 scm_cons (sym_cells_swept
,
376 scm_from_double (local_scm_gc_cells_swept
)),
377 scm_cons (sym_malloc_yield
,
378 scm_from_long(local_scm_gc_malloc_yield_percentage
)),
379 scm_cons (sym_cell_yield
,
380 scm_from_long (local_scm_gc_cell_yield_percentage
)),
381 scm_cons (sym_protected_objects
,
382 scm_from_ulong (local_protected_obj_count
)),
383 scm_cons (sym_heap_segments
, heap_segs
),
385 SCM_CRITICAL_SECTION_END
;
393 gc_start_stats (const char *what SCM_UNUSED
)
395 t_before_gc
= scm_c_get_internal_run_time ();
397 scm_gc_cells_marked_acc
+= (double) scm_gc_cells_swept
398 - (double) scm_gc_cells_collected
;
399 scm_gc_cells_swept_acc
+= (double) scm_gc_cells_swept
;
401 scm_gc_cell_yield_percentage
= ( scm_gc_cells_collected
* 100 ) / SCM_HEAP_SIZE
;
403 scm_gc_cells_swept
= 0;
404 scm_gc_cells_collected_1
= scm_gc_cells_collected
;
407 CELLS SWEPT is another word for the number of cells that were
408 examined during GC. YIELD is the number that we cleaned
409 out. MARKED is the number that weren't cleaned.
411 scm_gc_cells_collected
= 0;
412 scm_gc_malloc_collected
= 0;
413 scm_gc_ports_collected
= 0;
419 unsigned long t
= scm_c_get_internal_run_time ();
420 scm_gc_time_taken
+= (t
- t_before_gc
);
426 SCM_DEFINE (scm_object_address
, "object-address", 1, 0, 0,
428 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
429 "returned by this function for @var{obj}")
430 #define FUNC_NAME s_scm_object_address
432 return scm_from_ulong (SCM_UNPACK (obj
));
437 SCM_DEFINE (scm_gc
, "gc", 0, 0, 0,
439 "Scans all of SCM objects and reclaims for further use those that are\n"
440 "no longer accessible.")
441 #define FUNC_NAME s_scm_gc
443 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
444 scm_gc_running_p
= 1;
446 scm_gc_running_p
= 0;
447 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
448 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
449 return SCM_UNSPECIFIED
;
456 /* The master is global and common while the freelist will be
457 * individual for each thread.
461 scm_gc_for_newcell (scm_t_cell_type_statistics
*freelist
, SCM
*free_cells
)
466 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
467 scm_gc_running_p
= 1;
469 *free_cells
= scm_i_sweep_some_segments (freelist
);
470 if (*free_cells
== SCM_EOL
&& scm_i_gc_grow_heap_p (freelist
))
472 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
473 *free_cells
= scm_i_sweep_some_segments (freelist
);
476 if (*free_cells
== SCM_EOL
)
479 with the advent of lazy sweep, GC yield is only known just
482 scm_i_adjust_min_yield (freelist
);
485 out of fresh cells. Try to get some new ones.
491 *free_cells
= scm_i_sweep_some_segments (freelist
);
494 if (*free_cells
== SCM_EOL
)
497 failed getting new cells. Get new juice or die.
499 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
500 *free_cells
= scm_i_sweep_some_segments (freelist
);
503 if (*free_cells
== SCM_EOL
)
508 *free_cells
= SCM_FREE_CELL_CDR (cell
);
510 scm_gc_running_p
= 0;
511 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
514 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
520 scm_t_c_hook scm_before_gc_c_hook
;
521 scm_t_c_hook scm_before_mark_c_hook
;
522 scm_t_c_hook scm_before_sweep_c_hook
;
523 scm_t_c_hook scm_after_sweep_c_hook
;
524 scm_t_c_hook scm_after_gc_c_hook
;
526 /* Must be called while holding scm_i_sweep_mutex.
530 scm_i_gc (const char *what
)
532 scm_i_thread_put_to_sleep ();
534 scm_c_hook_run (&scm_before_gc_c_hook
, 0);
537 fprintf (stderr
,"gc reason %s\n", what
);
540 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist
))
542 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2
)) ? "o" : "m"));
545 gc_start_stats (what
);
548 Set freelists to NULL so scm_cons() always triggers gc, causing
549 the assertion above to fail.
551 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
552 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
555 Let's finish the sweep. The conservative GC might point into the
556 garbage, and marking that would create a mess.
558 scm_i_sweep_all_segments("GC");
559 if (scm_mallocated
< scm_i_deprecated_memory_return
)
561 /* The byte count of allocated objects has underflowed. This is
562 probably because you forgot to report the sizes of objects you
563 have allocated, by calling scm_done_malloc or some such. When
564 the GC freed them, it subtracted their size from
565 scm_mallocated, which underflowed. */
567 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
568 "This is probably because the GC hasn't been correctly informed\n"
569 "about object sizes\n");
572 scm_mallocated
-= scm_i_deprecated_memory_return
;
577 scm_c_hook_run (&scm_before_mark_c_hook
, 0);
579 scm_gc_mark_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
583 TODO: the after_sweep hook should probably be moved to just before
584 the mark, since that's where the sweep is finished in lazy
587 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
588 original meaning implied at least two things: that it would be
591 1. the freelist is re-initialized (no evaluation possible, though)
595 2. the heap is "fresh"
596 (it is well-defined what data is used and what is not)
598 Neither of these conditions would hold just before the mark phase.
600 Of course, the lazy sweeping has muddled the distinction between
601 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
602 there were no difference, it would still be useful to have two
603 distinct classes of hook functions since this can prevent some
604 bad interference when several modules adds gc hooks.
607 scm_c_hook_run (&scm_before_sweep_c_hook
, 0);
609 scm_c_hook_run (&scm_after_sweep_c_hook
, 0);
613 scm_i_thread_wake_up ();
616 For debugging purposes, you could do
617 scm_i_sweep_all_segments("debug"), but then the remains of the
618 cell aren't left to analyse.
623 /* {GC Protection Helper Functions}
628 * If within a function you need to protect one or more scheme objects from
629 * garbage collection, pass them as parameters to one of the
630 * scm_remember_upto_here* functions below. These functions don't do
631 * anything, but since the compiler does not know that they are actually
632 * no-ops, it will generate code that calls these functions with the given
633 * parameters. Therefore, you can be sure that the compiler will keep those
634 * scheme values alive (on the stack or in a register) up to the point where
635 * scm_remember_upto_here* is called. In other words, place the call to
636 * scm_remember_upto_here* _behind_ the last code in your function, that
637 * depends on the scheme object to exist.
639 * Example: We want to make sure that the string object str does not get
640 * garbage collected during the execution of 'some_function' in the code
641 * below, because otherwise the characters belonging to str would be freed and
642 * 'some_function' might access freed memory. To make sure that the compiler
643 * keeps str alive on the stack or in a register such that it is visible to
644 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
645 * call to 'some_function'. Note that this would not be necessary if str was
646 * used anyway after the call to 'some_function'.
647 * char *chars = scm_i_string_chars (str);
648 * some_function (chars);
649 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
652 /* Remove any macro versions of these while defining the functions.
653 Functions are always included in the library, for upward binary
654 compatibility and in case combinations of GCC and non-GCC are used. */
655 #undef scm_remember_upto_here_1
656 #undef scm_remember_upto_here_2
659 scm_remember_upto_here_1 (SCM obj SCM_UNUSED
)
661 /* Empty. Protects a single object from garbage collection. */
665 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED
, SCM obj2 SCM_UNUSED
)
667 /* Empty. Protects two objects from garbage collection. */
671 scm_remember_upto_here (SCM obj SCM_UNUSED
, ...)
673 /* Empty. Protects any number of objects from garbage collection. */
677 These crazy functions prevent garbage collection
678 of arguments after the first argument by
679 ensuring they remain live throughout the
680 function because they are used in the last
681 line of the code block.
682 It'd be better to have a nice compiler hint to
683 aid the conservative stack-scanning GC. --03/09/00 gjb */
685 scm_return_first (SCM elt
, ...)
691 scm_return_first_int (int i
, ...)
698 scm_permanent_object (SCM obj
)
700 SCM cell
= scm_cons (obj
, SCM_EOL
);
701 SCM_CRITICAL_SECTION_START
;
702 SCM_SETCDR (cell
, scm_permobjs
);
704 SCM_CRITICAL_SECTION_END
;
709 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
710 other references are dropped, until the object is unprotected by calling
711 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
712 i. e. it is possible to protect the same object several times, but it is
713 necessary to unprotect the object the same number of times to actually get
714 the object unprotected. It is an error to unprotect an object more often
715 than it has been protected before. The function scm_protect_object returns
719 /* Implementation note: For every object X, there is a counter which
720 scm_gc_protect_object(X) increments and scm_gc_unprotect_object(X) decrements.
726 scm_gc_protect_object (SCM obj
)
730 /* This critical section barrier will be replaced by a mutex. */
731 SCM_CRITICAL_SECTION_START
;
733 handle
= scm_hashq_create_handle_x (scm_protects
, obj
, scm_from_int (0));
734 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
736 protected_obj_count
++;
738 SCM_CRITICAL_SECTION_END
;
744 /* Remove any protection for OBJ established by a prior call to
745 scm_protect_object. This function returns OBJ.
747 See scm_protect_object for more information. */
749 scm_gc_unprotect_object (SCM obj
)
753 /* This critical section barrier will be replaced by a mutex. */
754 SCM_CRITICAL_SECTION_START
;
756 if (scm_gc_running_p
)
758 fprintf (stderr
, "scm_unprotect_object called during GC.\n");
762 handle
= scm_hashq_get_handle (scm_protects
, obj
);
764 if (scm_is_false (handle
))
766 fprintf (stderr
, "scm_unprotect_object called on unprotected object\n");
771 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
772 if (scm_is_eq (count
, scm_from_int (0)))
773 scm_hashq_remove_x (scm_protects
, obj
);
775 SCM_SETCDR (handle
, count
);
777 protected_obj_count
--;
779 SCM_CRITICAL_SECTION_END
;
785 scm_gc_register_root (SCM
*p
)
788 SCM key
= scm_from_ulong ((unsigned long) p
);
790 /* This critical section barrier will be replaced by a mutex. */
791 SCM_CRITICAL_SECTION_START
;
793 handle
= scm_hashv_create_handle_x (scm_gc_registered_roots
, key
,
795 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
797 SCM_CRITICAL_SECTION_END
;
801 scm_gc_unregister_root (SCM
*p
)
804 SCM key
= scm_from_ulong ((unsigned long) p
);
806 /* This critical section barrier will be replaced by a mutex. */
807 SCM_CRITICAL_SECTION_START
;
809 handle
= scm_hashv_get_handle (scm_gc_registered_roots
, key
);
811 if (scm_is_false (handle
))
813 fprintf (stderr
, "scm_gc_unregister_root called on unregistered root\n");
818 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
819 if (scm_is_eq (count
, scm_from_int (0)))
820 scm_hashv_remove_x (scm_gc_registered_roots
, key
);
822 SCM_SETCDR (handle
, count
);
825 SCM_CRITICAL_SECTION_END
;
829 scm_gc_register_roots (SCM
*b
, unsigned long n
)
832 for (; p
< b
+ n
; ++p
)
833 scm_gc_register_root (p
);
837 scm_gc_unregister_roots (SCM
*b
, unsigned long n
)
840 for (; p
< b
+ n
; ++p
)
841 scm_gc_unregister_root (p
);
844 int scm_i_terminating
;
850 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
853 /* Get an integer from an environment variable. */
855 scm_getenv_int (const char *var
, int def
)
858 char *val
= getenv (var
);
862 res
= strtol (val
, &end
, 10);
869 scm_storage_prehistory ()
871 scm_c_hook_init (&scm_before_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
872 scm_c_hook_init (&scm_before_mark_c_hook
, 0, SCM_C_HOOK_NORMAL
);
873 scm_c_hook_init (&scm_before_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
874 scm_c_hook_init (&scm_after_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
875 scm_c_hook_init (&scm_after_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
878 scm_i_pthread_mutex_t scm_i_gc_admin_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
885 j
= SCM_NUM_PROTECTS
;
887 scm_sys_protects
[--j
] = SCM_BOOL_F
;
889 scm_gc_init_freelist();
890 scm_gc_init_malloc ();
892 j
= SCM_HEAP_SEG_SIZE
;
895 /* Initialise the list of ports. */
896 scm_i_port_table
= (scm_t_port
**)
897 malloc (sizeof (scm_t_port
*) * scm_i_port_table_room
);
898 if (!scm_i_port_table
)
902 /* We can't have a cleanup handler since we have no thread to run it
909 on_exit (cleanup
, 0);
915 scm_stand_in_procs
= scm_c_make_hash_table (257);
916 scm_permobjs
= SCM_EOL
;
917 scm_protects
= scm_c_make_hash_table (31);
918 scm_gc_registered_roots
= scm_c_make_hash_table (31);
925 SCM scm_after_gc_hook
;
929 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
930 * is run after the gc, as soon as the asynchronous events are handled by the
934 gc_async_thunk (void)
936 scm_c_run_hook (scm_after_gc_hook
, SCM_EOL
);
937 return SCM_UNSPECIFIED
;
941 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
942 * the garbage collection. The only purpose of this function is to mark the
943 * gc_async (which will eventually lead to the execution of the
947 mark_gc_async (void * hook_data SCM_UNUSED
,
948 void *func_data SCM_UNUSED
,
949 void *data SCM_UNUSED
)
951 /* If cell access debugging is enabled, the user may choose to perform
952 * additional garbage collections after an arbitrary number of cell
953 * accesses. We don't want the scheme level after-gc-hook to be performed
954 * for each of these garbage collections for the following reason: The
955 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
956 * after-gc-hook was performed with every gc, and if the gc was performed
957 * after a very small number of cell accesses, then the number of cell
958 * accesses during the execution of the after-gc-hook will suffice to cause
959 * the execution of the next gc. Then, guile would keep executing the
960 * after-gc-hook over and over again, and would never come to do other
963 * To overcome this problem, if cell access debugging with additional
964 * garbage collections is enabled, the after-gc-hook is never run by the
965 * garbage collecter. When running guile with cell access debugging and the
966 * execution of the after-gc-hook is desired, then it is necessary to run
967 * the hook explicitly from the user code. This has the effect, that from
968 * the scheme level point of view it seems that garbage collection is
969 * performed with a much lower frequency than it actually is. Obviously,
970 * this will not work for code that depends on a fixed one to one
971 * relationship between the execution counts of the C level garbage
972 * collection hooks and the execution count of the scheme level
976 #if (SCM_DEBUG_CELL_ACCESSES == 1)
977 if (scm_debug_cells_gc_interval
== 0)
978 scm_system_async_mark (gc_async
);
980 scm_system_async_mark (gc_async
);
991 scm_after_gc_hook
= scm_permanent_object (scm_make_hook (SCM_INUM0
));
992 scm_c_define ("after-gc-hook", scm_after_gc_hook
);
994 gc_async
= scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0
,
997 scm_c_hook_add (&scm_after_gc_c_hook
, mark_gc_async
, NULL
, 0);
999 #include "libguile/gc.x"
1005 #define FUNC_NAME "scm_gc_sweep"
1007 scm_i_deprecated_memory_return
= 0;
1009 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist
);
1010 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2
);
1013 NOTHING HERE: LAZY SWEEPING !
1015 scm_i_reset_segments ();
1017 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
1018 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
1020 /* Invalidate the freelists of other threads. */
1021 scm_i_thread_invalidate_freelists ();