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 /* GC Statistics Keeping
215 unsigned long scm_cells_allocated
= 0;
216 unsigned long scm_mallocated
= 0;
217 unsigned long scm_gc_cells_collected
;
218 unsigned long scm_gc_cells_collected_1
= 0; /* previous GC yield */
219 unsigned long scm_gc_malloc_collected
;
220 unsigned long scm_gc_ports_collected
;
221 unsigned long scm_gc_time_taken
= 0;
222 static unsigned long t_before_gc
;
223 unsigned long scm_gc_mark_time_taken
= 0;
224 unsigned long scm_gc_times
= 0;
225 unsigned long scm_gc_cells_swept
= 0;
226 double scm_gc_cells_marked_acc
= 0.;
227 double scm_gc_cells_swept_acc
= 0.;
228 int scm_gc_cell_yield_percentage
=0;
229 int scm_gc_malloc_yield_percentage
= 0;
230 unsigned long protected_obj_count
= 0;
233 SCM_SYMBOL (sym_cells_allocated
, "cells-allocated");
234 SCM_SYMBOL (sym_heap_size
, "cell-heap-size");
235 SCM_SYMBOL (sym_mallocated
, "bytes-malloced");
236 SCM_SYMBOL (sym_mtrigger
, "gc-malloc-threshold");
237 SCM_SYMBOL (sym_heap_segments
, "cell-heap-segments");
238 SCM_SYMBOL (sym_gc_time_taken
, "gc-time-taken");
239 SCM_SYMBOL (sym_gc_mark_time_taken
, "gc-mark-time-taken");
240 SCM_SYMBOL (sym_times
, "gc-times");
241 SCM_SYMBOL (sym_cells_marked
, "cells-marked");
242 SCM_SYMBOL (sym_cells_swept
, "cells-swept");
243 SCM_SYMBOL (sym_malloc_yield
, "malloc-yield");
244 SCM_SYMBOL (sym_cell_yield
, "cell-yield");
245 SCM_SYMBOL (sym_protected_objects
, "protected-objects");
250 /* Number of calls to SCM_NEWCELL since startup. */
251 unsigned scm_newcell_count
;
252 unsigned scm_newcell2_count
;
255 /* {Scheme Interface to GC}
258 tag_table_to_type_alist (void *closure
, SCM key
, SCM val
, SCM acc
)
260 if (scm_is_integer (key
))
262 int c_tag
= scm_to_int (key
);
264 char const * name
= scm_i_tag_name (c_tag
);
267 key
= scm_from_locale_string (name
);
272 sprintf (s
, "tag %d", c_tag
);
273 key
= scm_from_locale_string (s
);
277 return scm_cons (scm_cons (key
, val
), acc
);
280 SCM_DEFINE (scm_gc_live_object_stats
, "gc-live-object-stats", 0, 0, 0,
282 "Return an alist of statistics of the current live objects. ")
283 #define FUNC_NAME s_scm_gc_live_object_stats
285 SCM tab
= scm_make_hash_table (scm_from_int (57));
288 scm_i_all_segments_statistics (tab
);
291 = scm_internal_hash_fold (&tag_table_to_type_alist
, NULL
, SCM_EOL
, tab
);
297 extern int scm_gc_malloc_yield_percentage
;
298 SCM_DEFINE (scm_gc_stats
, "gc-stats", 0, 0, 0,
300 "Return an association list of statistics about Guile's current\n"
302 #define FUNC_NAME s_scm_gc_stats
305 SCM heap_segs
= SCM_EOL
;
306 unsigned long int local_scm_mtrigger
;
307 unsigned long int local_scm_mallocated
;
308 unsigned long int local_scm_heap_size
;
309 int local_scm_gc_cell_yield_percentage
;
310 int local_scm_gc_malloc_yield_percentage
;
311 unsigned long int local_scm_cells_allocated
;
312 unsigned long int local_scm_gc_time_taken
;
313 unsigned long int local_scm_gc_times
;
314 unsigned long int local_scm_gc_mark_time_taken
;
315 unsigned long int local_protected_obj_count
;
316 double local_scm_gc_cells_swept
;
317 double local_scm_gc_cells_marked
;
319 unsigned long *bounds
= 0;
320 int table_size
= scm_i_heap_segment_table_size
;
321 SCM_CRITICAL_SECTION_START
;
324 temporarily store the numbers, so as not to cause GC.
327 bounds
= malloc (sizeof (unsigned long) * table_size
* 2);
330 for (i
= table_size
; i
--; )
332 bounds
[2*i
] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[0];
333 bounds
[2*i
+1] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[1];
337 /* Below, we cons to produce the resulting list. We want a snapshot of
338 * the heap situation before consing.
340 local_scm_mtrigger
= scm_mtrigger
;
341 local_scm_mallocated
= scm_mallocated
;
342 local_scm_heap_size
= SCM_HEAP_SIZE
;
344 local_scm_cells_allocated
= scm_cells_allocated
;
346 local_scm_gc_time_taken
= scm_gc_time_taken
;
347 local_scm_gc_mark_time_taken
= scm_gc_mark_time_taken
;
348 local_scm_gc_times
= scm_gc_times
;
349 local_scm_gc_malloc_yield_percentage
= scm_gc_malloc_yield_percentage
;
350 local_scm_gc_cell_yield_percentage
= scm_gc_cell_yield_percentage
;
351 local_protected_obj_count
= protected_obj_count
;
352 local_scm_gc_cells_swept
=
353 (double) scm_gc_cells_swept_acc
354 + (double) scm_gc_cells_swept
;
355 local_scm_gc_cells_marked
= scm_gc_cells_marked_acc
356 +(double) scm_gc_cells_swept
357 -(double) scm_gc_cells_collected
;
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_heap_size
,
373 scm_from_ulong (local_scm_heap_size
)),
374 scm_cons (sym_mallocated
,
375 scm_from_ulong (local_scm_mallocated
)),
376 scm_cons (sym_mtrigger
,
377 scm_from_ulong (local_scm_mtrigger
)),
379 scm_from_ulong (local_scm_gc_times
)),
380 scm_cons (sym_gc_mark_time_taken
,
381 scm_from_ulong (local_scm_gc_mark_time_taken
)),
382 scm_cons (sym_cells_marked
,
383 scm_from_double (local_scm_gc_cells_marked
)),
384 scm_cons (sym_cells_swept
,
385 scm_from_double (local_scm_gc_cells_swept
)),
386 scm_cons (sym_malloc_yield
,
387 scm_from_long(local_scm_gc_malloc_yield_percentage
)),
388 scm_cons (sym_cell_yield
,
389 scm_from_long (local_scm_gc_cell_yield_percentage
)),
390 scm_cons (sym_protected_objects
,
391 scm_from_ulong (local_protected_obj_count
)),
392 scm_cons (sym_heap_segments
, heap_segs
),
394 SCM_CRITICAL_SECTION_END
;
402 gc_start_stats (const char *what SCM_UNUSED
)
404 t_before_gc
= scm_c_get_internal_run_time ();
406 scm_gc_cells_marked_acc
+= (double) scm_gc_cells_swept
407 - (double) scm_gc_cells_collected
;
408 scm_gc_cells_swept_acc
+= (double) scm_gc_cells_swept
;
410 scm_gc_cell_yield_percentage
= ( scm_gc_cells_collected
* 100 ) / SCM_HEAP_SIZE
;
412 scm_gc_cells_swept
= 0;
413 scm_gc_cells_collected_1
= scm_gc_cells_collected
;
416 CELLS SWEPT is another word for the number of cells that were
417 examined during GC. YIELD is the number that we cleaned
418 out. MARKED is the number that weren't cleaned.
420 scm_gc_cells_collected
= 0;
421 scm_gc_malloc_collected
= 0;
422 scm_gc_ports_collected
= 0;
428 unsigned long t
= scm_c_get_internal_run_time ();
429 scm_gc_time_taken
+= (t
- t_before_gc
);
435 SCM_DEFINE (scm_object_address
, "object-address", 1, 0, 0,
437 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
438 "returned by this function for @var{obj}")
439 #define FUNC_NAME s_scm_object_address
441 return scm_from_ulong (SCM_UNPACK (obj
));
446 SCM_DEFINE (scm_gc
, "gc", 0, 0, 0,
448 "Scans all of SCM objects and reclaims for further use those that are\n"
449 "no longer accessible.")
450 #define FUNC_NAME s_scm_gc
452 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
453 scm_gc_running_p
= 1;
455 /* njrev: It looks as though other places, e.g. scm_realloc,
456 can call scm_i_gc without acquiring the sweep mutex. Does this
457 matter? Also scm_i_gc (or its descendants) touch the
458 scm_sys_protects, which are protected in some cases
459 (e.g. scm_permobjs above in scm_gc_stats) by a critical section,
460 not by the sweep mutex. Shouldn't all the GC-relevant objects be
461 protected in the same way? */
462 scm_gc_running_p
= 0;
463 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
464 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
465 return SCM_UNSPECIFIED
;
472 /* The master is global and common while the freelist will be
473 * individual for each thread.
477 scm_gc_for_newcell (scm_t_cell_type_statistics
*freelist
, SCM
*free_cells
)
482 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
483 scm_gc_running_p
= 1;
485 *free_cells
= scm_i_sweep_some_segments (freelist
);
486 if (*free_cells
== SCM_EOL
&& scm_i_gc_grow_heap_p (freelist
))
488 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
489 *free_cells
= scm_i_sweep_some_segments (freelist
);
492 if (*free_cells
== SCM_EOL
)
495 with the advent of lazy sweep, GC yield is only known just
498 scm_i_adjust_min_yield (freelist
);
501 out of fresh cells. Try to get some new ones.
507 *free_cells
= scm_i_sweep_some_segments (freelist
);
510 if (*free_cells
== SCM_EOL
)
513 failed getting new cells. Get new juice or die.
515 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
516 *free_cells
= scm_i_sweep_some_segments (freelist
);
519 if (*free_cells
== SCM_EOL
)
524 *free_cells
= SCM_FREE_CELL_CDR (cell
);
526 scm_gc_running_p
= 0;
527 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
530 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
536 scm_t_c_hook scm_before_gc_c_hook
;
537 scm_t_c_hook scm_before_mark_c_hook
;
538 scm_t_c_hook scm_before_sweep_c_hook
;
539 scm_t_c_hook scm_after_sweep_c_hook
;
540 scm_t_c_hook scm_after_gc_c_hook
;
542 /* Must be called while holding scm_i_sweep_mutex.
546 scm_i_gc (const char *what
)
548 scm_i_thread_put_to_sleep ();
550 scm_c_hook_run (&scm_before_gc_c_hook
, 0);
553 fprintf (stderr
,"gc reason %s\n", what
);
556 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist
))
558 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2
)) ? "o" : "m"));
561 gc_start_stats (what
);
564 Set freelists to NULL so scm_cons() always triggers gc, causing
565 the assertion above to fail.
567 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
568 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
571 Let's finish the sweep. The conservative GC might point into the
572 garbage, and marking that would create a mess.
574 scm_i_sweep_all_segments("GC");
575 if (scm_mallocated
< scm_i_deprecated_memory_return
)
577 /* The byte count of allocated objects has underflowed. This is
578 probably because you forgot to report the sizes of objects you
579 have allocated, by calling scm_done_malloc or some such. When
580 the GC freed them, it subtracted their size from
581 scm_mallocated, which underflowed. */
583 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
584 "This is probably because the GC hasn't been correctly informed\n"
585 "about object sizes\n");
588 scm_mallocated
-= scm_i_deprecated_memory_return
;
593 scm_c_hook_run (&scm_before_mark_c_hook
, 0);
595 scm_gc_mark_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
599 TODO: the after_sweep hook should probably be moved to just before
600 the mark, since that's where the sweep is finished in lazy
603 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
604 original meaning implied at least two things: that it would be
607 1. the freelist is re-initialized (no evaluation possible, though)
611 2. the heap is "fresh"
612 (it is well-defined what data is used and what is not)
614 Neither of these conditions would hold just before the mark phase.
616 Of course, the lazy sweeping has muddled the distinction between
617 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
618 there were no difference, it would still be useful to have two
619 distinct classes of hook functions since this can prevent some
620 bad interference when several modules adds gc hooks.
623 scm_c_hook_run (&scm_before_sweep_c_hook
, 0);
625 scm_c_hook_run (&scm_after_sweep_c_hook
, 0);
629 scm_i_thread_wake_up ();
632 For debugging purposes, you could do
633 scm_i_sweep_all_segments("debug"), but then the remains of the
634 cell aren't left to analyse.
639 /* {GC Protection Helper Functions}
644 * If within a function you need to protect one or more scheme objects from
645 * garbage collection, pass them as parameters to one of the
646 * scm_remember_upto_here* functions below. These functions don't do
647 * anything, but since the compiler does not know that they are actually
648 * no-ops, it will generate code that calls these functions with the given
649 * parameters. Therefore, you can be sure that the compiler will keep those
650 * scheme values alive (on the stack or in a register) up to the point where
651 * scm_remember_upto_here* is called. In other words, place the call to
652 * scm_remember_upto_here* _behind_ the last code in your function, that
653 * depends on the scheme object to exist.
655 * Example: We want to make sure that the string object str does not get
656 * garbage collected during the execution of 'some_function' in the code
657 * below, because otherwise the characters belonging to str would be freed and
658 * 'some_function' might access freed memory. To make sure that the compiler
659 * keeps str alive on the stack or in a register such that it is visible to
660 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
661 * call to 'some_function'. Note that this would not be necessary if str was
662 * used anyway after the call to 'some_function'.
663 * char *chars = scm_i_string_chars (str);
664 * some_function (chars);
665 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
668 /* Remove any macro versions of these while defining the functions.
669 Functions are always included in the library, for upward binary
670 compatibility and in case combinations of GCC and non-GCC are used. */
671 #undef scm_remember_upto_here_1
672 #undef scm_remember_upto_here_2
675 scm_remember_upto_here_1 (SCM obj SCM_UNUSED
)
677 /* Empty. Protects a single object from garbage collection. */
681 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED
, SCM obj2 SCM_UNUSED
)
683 /* Empty. Protects two objects from garbage collection. */
687 scm_remember_upto_here (SCM obj SCM_UNUSED
, ...)
689 /* Empty. Protects any number of objects from garbage collection. */
693 These crazy functions prevent garbage collection
694 of arguments after the first argument by
695 ensuring they remain live throughout the
696 function because they are used in the last
697 line of the code block.
698 It'd be better to have a nice compiler hint to
699 aid the conservative stack-scanning GC. --03/09/00 gjb */
701 scm_return_first (SCM elt
, ...)
707 scm_return_first_int (int i
, ...)
714 scm_permanent_object (SCM obj
)
716 SCM cell
= scm_cons (obj
, SCM_EOL
);
717 SCM_CRITICAL_SECTION_START
;
718 SCM_SETCDR (cell
, scm_permobjs
);
720 SCM_CRITICAL_SECTION_END
;
725 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
726 other references are dropped, until the object is unprotected by calling
727 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
728 i. e. it is possible to protect the same object several times, but it is
729 necessary to unprotect the object the same number of times to actually get
730 the object unprotected. It is an error to unprotect an object more often
731 than it has been protected before. The function scm_protect_object returns
735 /* Implementation note: For every object X, there is a counter which
736 scm_gc_protect_object(X) increments and scm_gc_unprotect_object(X) decrements.
742 scm_gc_protect_object (SCM obj
)
746 /* This critical section barrier will be replaced by a mutex. */
747 /* njrev: Indeed; if my comment above is correct, there is the same
748 critsec/mutex inconsistency here. */
749 SCM_CRITICAL_SECTION_START
;
751 handle
= scm_hashq_create_handle_x (scm_protects
, obj
, scm_from_int (0));
752 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
754 protected_obj_count
++;
756 SCM_CRITICAL_SECTION_END
;
762 /* Remove any protection for OBJ established by a prior call to
763 scm_protect_object. This function returns OBJ.
765 See scm_protect_object for more information. */
767 scm_gc_unprotect_object (SCM obj
)
771 /* This critical section barrier will be replaced by a mutex. */
772 /* njrev: and again. */
773 SCM_CRITICAL_SECTION_START
;
775 if (scm_gc_running_p
)
777 fprintf (stderr
, "scm_unprotect_object called during GC.\n");
781 handle
= scm_hashq_get_handle (scm_protects
, obj
);
783 if (scm_is_false (handle
))
785 fprintf (stderr
, "scm_unprotect_object called on unprotected object\n");
790 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
791 if (scm_is_eq (count
, scm_from_int (0)))
792 scm_hashq_remove_x (scm_protects
, obj
);
794 SCM_SETCDR (handle
, count
);
796 protected_obj_count
--;
798 SCM_CRITICAL_SECTION_END
;
804 scm_gc_register_root (SCM
*p
)
807 SCM key
= scm_from_ulong ((unsigned long) p
);
809 /* This critical section barrier will be replaced by a mutex. */
810 /* njrev: and again. */
811 SCM_CRITICAL_SECTION_START
;
813 handle
= scm_hashv_create_handle_x (scm_gc_registered_roots
, key
,
815 /* njrev: note also that the above can probably signal an error */
816 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
818 SCM_CRITICAL_SECTION_END
;
822 scm_gc_unregister_root (SCM
*p
)
825 SCM key
= scm_from_ulong ((unsigned long) p
);
827 /* This critical section barrier will be replaced by a mutex. */
828 /* njrev: and again. */
829 SCM_CRITICAL_SECTION_START
;
831 handle
= scm_hashv_get_handle (scm_gc_registered_roots
, key
);
833 if (scm_is_false (handle
))
835 fprintf (stderr
, "scm_gc_unregister_root called on unregistered root\n");
840 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
841 if (scm_is_eq (count
, scm_from_int (0)))
842 scm_hashv_remove_x (scm_gc_registered_roots
, key
);
844 SCM_SETCDR (handle
, count
);
847 SCM_CRITICAL_SECTION_END
;
851 scm_gc_register_roots (SCM
*b
, unsigned long n
)
854 for (; p
< b
+ n
; ++p
)
855 scm_gc_register_root (p
);
859 scm_gc_unregister_roots (SCM
*b
, unsigned long n
)
862 for (; p
< b
+ n
; ++p
)
863 scm_gc_unregister_root (p
);
866 int scm_i_terminating
;
872 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
875 /* Get an integer from an environment variable. */
877 scm_getenv_int (const char *var
, int def
)
880 char *val
= getenv (var
);
884 res
= strtol (val
, &end
, 10);
891 scm_storage_prehistory ()
893 scm_c_hook_init (&scm_before_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
894 scm_c_hook_init (&scm_before_mark_c_hook
, 0, SCM_C_HOOK_NORMAL
);
895 scm_c_hook_init (&scm_before_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
896 scm_c_hook_init (&scm_after_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
897 scm_c_hook_init (&scm_after_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
900 scm_i_pthread_mutex_t scm_i_gc_admin_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
907 j
= SCM_NUM_PROTECTS
;
909 scm_sys_protects
[--j
] = SCM_BOOL_F
;
911 scm_gc_init_freelist();
912 scm_gc_init_malloc ();
914 j
= SCM_HEAP_SEG_SIZE
;
917 /* Initialise the list of ports. */
918 scm_i_port_table
= (scm_t_port
**)
919 malloc (sizeof (scm_t_port
*) * scm_i_port_table_room
);
920 if (!scm_i_port_table
)
924 /* We can't have a cleanup handler since we have no thread to run it
931 on_exit (cleanup
, 0);
937 scm_stand_in_procs
= scm_make_weak_key_hash_table (scm_from_int (257));
938 scm_permobjs
= SCM_EOL
;
939 scm_protects
= scm_c_make_hash_table (31);
940 scm_gc_registered_roots
= scm_c_make_hash_table (31);
947 SCM scm_after_gc_hook
;
951 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
952 * is run after the gc, as soon as the asynchronous events are handled by the
956 gc_async_thunk (void)
958 scm_c_run_hook (scm_after_gc_hook
, SCM_EOL
);
959 return SCM_UNSPECIFIED
;
963 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
964 * the garbage collection. The only purpose of this function is to mark the
965 * gc_async (which will eventually lead to the execution of the
969 mark_gc_async (void * hook_data SCM_UNUSED
,
970 void *func_data SCM_UNUSED
,
971 void *data SCM_UNUSED
)
973 /* If cell access debugging is enabled, the user may choose to perform
974 * additional garbage collections after an arbitrary number of cell
975 * accesses. We don't want the scheme level after-gc-hook to be performed
976 * for each of these garbage collections for the following reason: The
977 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
978 * after-gc-hook was performed with every gc, and if the gc was performed
979 * after a very small number of cell accesses, then the number of cell
980 * accesses during the execution of the after-gc-hook will suffice to cause
981 * the execution of the next gc. Then, guile would keep executing the
982 * after-gc-hook over and over again, and would never come to do other
985 * To overcome this problem, if cell access debugging with additional
986 * garbage collections is enabled, the after-gc-hook is never run by the
987 * garbage collecter. When running guile with cell access debugging and the
988 * execution of the after-gc-hook is desired, then it is necessary to run
989 * the hook explicitly from the user code. This has the effect, that from
990 * the scheme level point of view it seems that garbage collection is
991 * performed with a much lower frequency than it actually is. Obviously,
992 * this will not work for code that depends on a fixed one to one
993 * relationship between the execution counts of the C level garbage
994 * collection hooks and the execution count of the scheme level
998 #if (SCM_DEBUG_CELL_ACCESSES == 1)
999 if (scm_debug_cells_gc_interval
== 0)
1000 scm_system_async_mark (gc_async
);
1002 scm_system_async_mark (gc_async
);
1011 scm_gc_init_mark ();
1013 scm_after_gc_hook
= scm_permanent_object (scm_make_hook (SCM_INUM0
));
1014 scm_c_define ("after-gc-hook", scm_after_gc_hook
);
1016 gc_async
= scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0
,
1019 scm_c_hook_add (&scm_after_gc_c_hook
, mark_gc_async
, NULL
, 0);
1021 #include "libguile/gc.x"
1027 #define FUNC_NAME "scm_gc_sweep"
1029 scm_i_deprecated_memory_return
= 0;
1031 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist
);
1032 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2
);
1035 NOTHING HERE: LAZY SWEEPING !
1037 scm_i_reset_segments ();
1039 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
1040 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
1042 /* Invalidate the freelists of other threads. */
1043 scm_i_thread_invalidate_freelists ();