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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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));
282 scm_i_all_segments_statistics (tab
);
285 = scm_internal_hash_fold (&tag_table_to_type_alist
, NULL
, SCM_EOL
, tab
);
291 extern int scm_gc_malloc_yield_percentage
;
292 SCM_DEFINE (scm_gc_stats
, "gc-stats", 0, 0, 0,
294 "Return an association list of statistics about Guile's current\n"
296 #define FUNC_NAME s_scm_gc_stats
299 SCM heap_segs
= SCM_EOL
;
300 unsigned long int local_scm_mtrigger
;
301 unsigned long int local_scm_mallocated
;
302 unsigned long int local_scm_heap_size
;
303 int local_scm_gc_cell_yield_percentage
;
304 int local_scm_gc_malloc_yield_percentage
;
305 unsigned long int local_scm_cells_allocated
;
306 unsigned long int local_scm_gc_time_taken
;
307 unsigned long int local_scm_gc_times
;
308 unsigned long int local_scm_gc_mark_time_taken
;
309 unsigned long int local_protected_obj_count
;
310 double local_scm_gc_cells_swept
;
311 double local_scm_gc_cells_marked
;
313 unsigned long *bounds
= 0;
314 int table_size
= scm_i_heap_segment_table_size
;
315 SCM_CRITICAL_SECTION_START
;
318 temporarily store the numbers, so as not to cause GC.
321 bounds
= malloc (sizeof (int) * table_size
* 2);
324 for (i
= table_size
; i
--; )
326 bounds
[2*i
] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[0];
327 bounds
[2*i
+1] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[1];
331 /* Below, we cons to produce the resulting list. We want a snapshot of
332 * the heap situation before consing.
334 local_scm_mtrigger
= scm_mtrigger
;
335 local_scm_mallocated
= scm_mallocated
;
336 local_scm_heap_size
= SCM_HEAP_SIZE
;
338 local_scm_cells_allocated
= scm_cells_allocated
;
340 local_scm_gc_time_taken
= scm_gc_time_taken
;
341 local_scm_gc_mark_time_taken
= scm_gc_mark_time_taken
;
342 local_scm_gc_times
= scm_gc_times
;
343 local_scm_gc_malloc_yield_percentage
= scm_gc_malloc_yield_percentage
;
344 local_scm_gc_cell_yield_percentage
= scm_gc_cell_yield_percentage
;
345 local_protected_obj_count
= protected_obj_count
;
346 local_scm_gc_cells_swept
=
347 (double) scm_gc_cells_swept_acc
348 + (double) scm_gc_cells_swept
;
349 local_scm_gc_cells_marked
= scm_gc_cells_marked_acc
350 +(double) scm_gc_cells_swept
351 -(double) scm_gc_cells_collected
;
353 for (i
= table_size
; i
--;)
355 heap_segs
= scm_cons (scm_cons (scm_from_ulong (bounds
[2*i
]),
356 scm_from_ulong (bounds
[2*i
+1])),
359 /* njrev: can any of these scm_cons's or scm_list_n signal a memory
360 error? If so we need a frame here. */
362 scm_list_n (scm_cons (sym_gc_time_taken
,
363 scm_from_ulong (local_scm_gc_time_taken
)),
364 scm_cons (sym_cells_allocated
,
365 scm_from_ulong (local_scm_cells_allocated
)),
366 scm_cons (sym_heap_size
,
367 scm_from_ulong (local_scm_heap_size
)),
368 scm_cons (sym_mallocated
,
369 scm_from_ulong (local_scm_mallocated
)),
370 scm_cons (sym_mtrigger
,
371 scm_from_ulong (local_scm_mtrigger
)),
373 scm_from_ulong (local_scm_gc_times
)),
374 scm_cons (sym_gc_mark_time_taken
,
375 scm_from_ulong (local_scm_gc_mark_time_taken
)),
376 scm_cons (sym_cells_marked
,
377 scm_from_double (local_scm_gc_cells_marked
)),
378 scm_cons (sym_cells_swept
,
379 scm_from_double (local_scm_gc_cells_swept
)),
380 scm_cons (sym_malloc_yield
,
381 scm_from_long(local_scm_gc_malloc_yield_percentage
)),
382 scm_cons (sym_cell_yield
,
383 scm_from_long (local_scm_gc_cell_yield_percentage
)),
384 scm_cons (sym_protected_objects
,
385 scm_from_ulong (local_protected_obj_count
)),
386 scm_cons (sym_heap_segments
, heap_segs
),
388 SCM_CRITICAL_SECTION_END
;
396 gc_start_stats (const char *what SCM_UNUSED
)
398 t_before_gc
= scm_c_get_internal_run_time ();
400 scm_gc_cells_marked_acc
+= (double) scm_gc_cells_swept
401 - (double) scm_gc_cells_collected
;
402 scm_gc_cells_swept_acc
+= (double) scm_gc_cells_swept
;
404 scm_gc_cell_yield_percentage
= ( scm_gc_cells_collected
* 100 ) / SCM_HEAP_SIZE
;
406 scm_gc_cells_swept
= 0;
407 scm_gc_cells_collected_1
= scm_gc_cells_collected
;
410 CELLS SWEPT is another word for the number of cells that were
411 examined during GC. YIELD is the number that we cleaned
412 out. MARKED is the number that weren't cleaned.
414 scm_gc_cells_collected
= 0;
415 scm_gc_malloc_collected
= 0;
416 scm_gc_ports_collected
= 0;
422 unsigned long t
= scm_c_get_internal_run_time ();
423 scm_gc_time_taken
+= (t
- t_before_gc
);
429 SCM_DEFINE (scm_object_address
, "object-address", 1, 0, 0,
431 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
432 "returned by this function for @var{obj}")
433 #define FUNC_NAME s_scm_object_address
435 return scm_from_ulong (SCM_UNPACK (obj
));
440 SCM_DEFINE (scm_gc
, "gc", 0, 0, 0,
442 "Scans all of SCM objects and reclaims for further use those that are\n"
443 "no longer accessible.")
444 #define FUNC_NAME s_scm_gc
446 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
447 scm_gc_running_p
= 1;
449 /* njrev: It looks as though other places, e.g. scm_realloc,
450 can call scm_i_gc without acquiring the sweep mutex. Does this
451 matter? Also scm_i_gc (or its descendants) touch the
452 scm_sys_protects, which are protected in some cases
453 (e.g. scm_permobjs above in scm_gc_stats) by a critical section,
454 not by the sweep mutex. Shouldn't all the GC-relevant objects be
455 protected in the same way? */
456 scm_gc_running_p
= 0;
457 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
458 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
459 return SCM_UNSPECIFIED
;
466 /* The master is global and common while the freelist will be
467 * individual for each thread.
471 scm_gc_for_newcell (scm_t_cell_type_statistics
*freelist
, SCM
*free_cells
)
476 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
477 scm_gc_running_p
= 1;
479 *free_cells
= scm_i_sweep_some_segments (freelist
);
480 if (*free_cells
== SCM_EOL
&& scm_i_gc_grow_heap_p (freelist
))
482 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
483 *free_cells
= scm_i_sweep_some_segments (freelist
);
486 if (*free_cells
== SCM_EOL
)
489 with the advent of lazy sweep, GC yield is only known just
492 scm_i_adjust_min_yield (freelist
);
495 out of fresh cells. Try to get some new ones.
501 *free_cells
= scm_i_sweep_some_segments (freelist
);
504 if (*free_cells
== SCM_EOL
)
507 failed getting new cells. Get new juice or die.
509 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
510 *free_cells
= scm_i_sweep_some_segments (freelist
);
513 if (*free_cells
== SCM_EOL
)
518 *free_cells
= SCM_FREE_CELL_CDR (cell
);
520 scm_gc_running_p
= 0;
521 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
524 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
530 scm_t_c_hook scm_before_gc_c_hook
;
531 scm_t_c_hook scm_before_mark_c_hook
;
532 scm_t_c_hook scm_before_sweep_c_hook
;
533 scm_t_c_hook scm_after_sweep_c_hook
;
534 scm_t_c_hook scm_after_gc_c_hook
;
536 /* Must be called while holding scm_i_sweep_mutex.
540 scm_i_gc (const char *what
)
542 scm_i_thread_put_to_sleep ();
544 scm_c_hook_run (&scm_before_gc_c_hook
, 0);
547 fprintf (stderr
,"gc reason %s\n", what
);
550 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist
))
552 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2
)) ? "o" : "m"));
555 gc_start_stats (what
);
558 Set freelists to NULL so scm_cons() always triggers gc, causing
559 the assertion above to fail.
561 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
562 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
565 Let's finish the sweep. The conservative GC might point into the
566 garbage, and marking that would create a mess.
568 scm_i_sweep_all_segments("GC");
569 if (scm_mallocated
< scm_i_deprecated_memory_return
)
571 /* The byte count of allocated objects has underflowed. This is
572 probably because you forgot to report the sizes of objects you
573 have allocated, by calling scm_done_malloc or some such. When
574 the GC freed them, it subtracted their size from
575 scm_mallocated, which underflowed. */
577 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
578 "This is probably because the GC hasn't been correctly informed\n"
579 "about object sizes\n");
582 scm_mallocated
-= scm_i_deprecated_memory_return
;
587 scm_c_hook_run (&scm_before_mark_c_hook
, 0);
589 scm_gc_mark_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
593 TODO: the after_sweep hook should probably be moved to just before
594 the mark, since that's where the sweep is finished in lazy
597 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
598 original meaning implied at least two things: that it would be
601 1. the freelist is re-initialized (no evaluation possible, though)
605 2. the heap is "fresh"
606 (it is well-defined what data is used and what is not)
608 Neither of these conditions would hold just before the mark phase.
610 Of course, the lazy sweeping has muddled the distinction between
611 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
612 there were no difference, it would still be useful to have two
613 distinct classes of hook functions since this can prevent some
614 bad interference when several modules adds gc hooks.
617 scm_c_hook_run (&scm_before_sweep_c_hook
, 0);
619 scm_c_hook_run (&scm_after_sweep_c_hook
, 0);
623 scm_i_thread_wake_up ();
626 For debugging purposes, you could do
627 scm_i_sweep_all_segments("debug"), but then the remains of the
628 cell aren't left to analyse.
633 /* {GC Protection Helper Functions}
638 * If within a function you need to protect one or more scheme objects from
639 * garbage collection, pass them as parameters to one of the
640 * scm_remember_upto_here* functions below. These functions don't do
641 * anything, but since the compiler does not know that they are actually
642 * no-ops, it will generate code that calls these functions with the given
643 * parameters. Therefore, you can be sure that the compiler will keep those
644 * scheme values alive (on the stack or in a register) up to the point where
645 * scm_remember_upto_here* is called. In other words, place the call to
646 * scm_remember_upto_here* _behind_ the last code in your function, that
647 * depends on the scheme object to exist.
649 * Example: We want to make sure that the string object str does not get
650 * garbage collected during the execution of 'some_function' in the code
651 * below, because otherwise the characters belonging to str would be freed and
652 * 'some_function' might access freed memory. To make sure that the compiler
653 * keeps str alive on the stack or in a register such that it is visible to
654 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
655 * call to 'some_function'. Note that this would not be necessary if str was
656 * used anyway after the call to 'some_function'.
657 * char *chars = scm_i_string_chars (str);
658 * some_function (chars);
659 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
662 /* Remove any macro versions of these while defining the functions.
663 Functions are always included in the library, for upward binary
664 compatibility and in case combinations of GCC and non-GCC are used. */
665 #undef scm_remember_upto_here_1
666 #undef scm_remember_upto_here_2
669 scm_remember_upto_here_1 (SCM obj SCM_UNUSED
)
671 /* Empty. Protects a single object from garbage collection. */
675 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED
, SCM obj2 SCM_UNUSED
)
677 /* Empty. Protects two objects from garbage collection. */
681 scm_remember_upto_here (SCM obj SCM_UNUSED
, ...)
683 /* Empty. Protects any number of objects from garbage collection. */
687 These crazy functions prevent garbage collection
688 of arguments after the first argument by
689 ensuring they remain live throughout the
690 function because they are used in the last
691 line of the code block.
692 It'd be better to have a nice compiler hint to
693 aid the conservative stack-scanning GC. --03/09/00 gjb */
695 scm_return_first (SCM elt
, ...)
701 scm_return_first_int (int i
, ...)
708 scm_permanent_object (SCM obj
)
710 SCM cell
= scm_cons (obj
, SCM_EOL
);
711 SCM_CRITICAL_SECTION_START
;
712 SCM_SETCDR (cell
, scm_permobjs
);
714 SCM_CRITICAL_SECTION_END
;
719 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
720 other references are dropped, until the object is unprotected by calling
721 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
722 i. e. it is possible to protect the same object several times, but it is
723 necessary to unprotect the object the same number of times to actually get
724 the object unprotected. It is an error to unprotect an object more often
725 than it has been protected before. The function scm_protect_object returns
729 /* Implementation note: For every object X, there is a counter which
730 scm_gc_protect_object(X) increments and scm_gc_unprotect_object(X) decrements.
736 scm_gc_protect_object (SCM obj
)
740 /* This critical section barrier will be replaced by a mutex. */
741 /* njrev: Indeed; if my comment above is correct, there is the same
742 critsec/mutex inconsistency here. */
743 SCM_CRITICAL_SECTION_START
;
745 handle
= scm_hashq_create_handle_x (scm_protects
, obj
, scm_from_int (0));
746 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
748 protected_obj_count
++;
750 SCM_CRITICAL_SECTION_END
;
756 /* Remove any protection for OBJ established by a prior call to
757 scm_protect_object. This function returns OBJ.
759 See scm_protect_object for more information. */
761 scm_gc_unprotect_object (SCM obj
)
765 /* This critical section barrier will be replaced by a mutex. */
766 /* njrev: and again. */
767 SCM_CRITICAL_SECTION_START
;
769 if (scm_gc_running_p
)
771 fprintf (stderr
, "scm_unprotect_object called during GC.\n");
775 handle
= scm_hashq_get_handle (scm_protects
, obj
);
777 if (scm_is_false (handle
))
779 fprintf (stderr
, "scm_unprotect_object called on unprotected object\n");
784 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
785 if (scm_is_eq (count
, scm_from_int (0)))
786 scm_hashq_remove_x (scm_protects
, obj
);
788 SCM_SETCDR (handle
, count
);
790 protected_obj_count
--;
792 SCM_CRITICAL_SECTION_END
;
798 scm_gc_register_root (SCM
*p
)
801 SCM key
= scm_from_ulong ((unsigned long) p
);
803 /* This critical section barrier will be replaced by a mutex. */
804 /* njrev: and again. */
805 SCM_CRITICAL_SECTION_START
;
807 handle
= scm_hashv_create_handle_x (scm_gc_registered_roots
, key
,
809 /* njrev: note also that the above can probably signal an error */
810 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
812 SCM_CRITICAL_SECTION_END
;
816 scm_gc_unregister_root (SCM
*p
)
819 SCM key
= scm_from_ulong ((unsigned long) p
);
821 /* This critical section barrier will be replaced by a mutex. */
822 /* njrev: and again. */
823 SCM_CRITICAL_SECTION_START
;
825 handle
= scm_hashv_get_handle (scm_gc_registered_roots
, key
);
827 if (scm_is_false (handle
))
829 fprintf (stderr
, "scm_gc_unregister_root called on unregistered root\n");
834 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
835 if (scm_is_eq (count
, scm_from_int (0)))
836 scm_hashv_remove_x (scm_gc_registered_roots
, key
);
838 SCM_SETCDR (handle
, count
);
841 SCM_CRITICAL_SECTION_END
;
845 scm_gc_register_roots (SCM
*b
, unsigned long n
)
848 for (; p
< b
+ n
; ++p
)
849 scm_gc_register_root (p
);
853 scm_gc_unregister_roots (SCM
*b
, unsigned long n
)
856 for (; p
< b
+ n
; ++p
)
857 scm_gc_unregister_root (p
);
860 int scm_i_terminating
;
866 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
869 /* Get an integer from an environment variable. */
871 scm_getenv_int (const char *var
, int def
)
874 char *val
= getenv (var
);
878 res
= strtol (val
, &end
, 10);
885 scm_storage_prehistory ()
887 scm_c_hook_init (&scm_before_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
888 scm_c_hook_init (&scm_before_mark_c_hook
, 0, SCM_C_HOOK_NORMAL
);
889 scm_c_hook_init (&scm_before_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
890 scm_c_hook_init (&scm_after_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
891 scm_c_hook_init (&scm_after_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
894 scm_i_pthread_mutex_t scm_i_gc_admin_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
901 j
= SCM_NUM_PROTECTS
;
903 scm_sys_protects
[--j
] = SCM_BOOL_F
;
905 scm_gc_init_freelist();
906 scm_gc_init_malloc ();
908 j
= SCM_HEAP_SEG_SIZE
;
911 /* Initialise the list of ports. */
912 scm_i_port_table
= (scm_t_port
**)
913 malloc (sizeof (scm_t_port
*) * scm_i_port_table_room
);
914 if (!scm_i_port_table
)
918 /* We can't have a cleanup handler since we have no thread to run it
925 on_exit (cleanup
, 0);
931 scm_stand_in_procs
= scm_c_make_hash_table (257);
932 scm_permobjs
= SCM_EOL
;
933 scm_protects
= scm_c_make_hash_table (31);
934 scm_gc_registered_roots
= scm_c_make_hash_table (31);
941 SCM scm_after_gc_hook
;
945 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
946 * is run after the gc, as soon as the asynchronous events are handled by the
950 gc_async_thunk (void)
952 scm_c_run_hook (scm_after_gc_hook
, SCM_EOL
);
953 return SCM_UNSPECIFIED
;
957 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
958 * the garbage collection. The only purpose of this function is to mark the
959 * gc_async (which will eventually lead to the execution of the
963 mark_gc_async (void * hook_data SCM_UNUSED
,
964 void *func_data SCM_UNUSED
,
965 void *data SCM_UNUSED
)
967 /* If cell access debugging is enabled, the user may choose to perform
968 * additional garbage collections after an arbitrary number of cell
969 * accesses. We don't want the scheme level after-gc-hook to be performed
970 * for each of these garbage collections for the following reason: The
971 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
972 * after-gc-hook was performed with every gc, and if the gc was performed
973 * after a very small number of cell accesses, then the number of cell
974 * accesses during the execution of the after-gc-hook will suffice to cause
975 * the execution of the next gc. Then, guile would keep executing the
976 * after-gc-hook over and over again, and would never come to do other
979 * To overcome this problem, if cell access debugging with additional
980 * garbage collections is enabled, the after-gc-hook is never run by the
981 * garbage collecter. When running guile with cell access debugging and the
982 * execution of the after-gc-hook is desired, then it is necessary to run
983 * the hook explicitly from the user code. This has the effect, that from
984 * the scheme level point of view it seems that garbage collection is
985 * performed with a much lower frequency than it actually is. Obviously,
986 * this will not work for code that depends on a fixed one to one
987 * relationship between the execution counts of the C level garbage
988 * collection hooks and the execution count of the scheme level
992 #if (SCM_DEBUG_CELL_ACCESSES == 1)
993 if (scm_debug_cells_gc_interval
== 0)
994 scm_system_async_mark (gc_async
);
996 scm_system_async_mark (gc_async
);
1005 scm_gc_init_mark ();
1007 scm_after_gc_hook
= scm_permanent_object (scm_make_hook (SCM_INUM0
));
1008 scm_c_define ("after-gc-hook", scm_after_gc_hook
);
1010 gc_async
= scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0
,
1013 scm_c_hook_add (&scm_after_gc_c_hook
, mark_gc_async
, NULL
, 0);
1015 #include "libguile/gc.x"
1021 #define FUNC_NAME "scm_gc_sweep"
1023 scm_i_deprecated_memory_return
= 0;
1025 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist
);
1026 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2
);
1029 NOTHING HERE: LAZY SWEEPING !
1031 scm_i_reset_segments ();
1033 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
1034 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
1036 /* Invalidate the freelists of other threads. */
1037 scm_i_thread_invalidate_freelists ();