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
);
270 key
= scm_from_locale_string (name
);
275 sprintf (s
, "tag %d", c_tag
);
276 key
= scm_from_locale_string (s
);
278 return scm_cons (scm_cons (key
, val
), acc
);
281 SCM_DEFINE (scm_gc_live_object_stats
, "gc-live-object-stats", 0, 0, 0,
283 "Return an alist of statistics of the current live objects. ")
284 #define FUNC_NAME s_scm_gc_live_object_stats
286 SCM tab
= scm_make_hash_table (scm_from_int (57));
289 scm_i_all_segments_statistics (tab
);
292 = scm_internal_hash_fold (&tag_table_to_type_alist
, NULL
, SCM_EOL
, tab
);
298 extern int scm_gc_malloc_yield_percentage
;
299 SCM_DEFINE (scm_gc_stats
, "gc-stats", 0, 0, 0,
301 "Return an association list of statistics about Guile's current\n"
303 #define FUNC_NAME s_scm_gc_stats
306 SCM heap_segs
= SCM_EOL
;
307 unsigned long int local_scm_mtrigger
;
308 unsigned long int local_scm_mallocated
;
309 unsigned long int local_scm_heap_size
;
310 int local_scm_gc_cell_yield_percentage
;
311 int local_scm_gc_malloc_yield_percentage
;
312 unsigned long int local_scm_cells_allocated
;
313 unsigned long int local_scm_gc_time_taken
;
314 unsigned long int local_scm_gc_times
;
315 unsigned long int local_scm_gc_mark_time_taken
;
316 unsigned long int local_protected_obj_count
;
317 double local_scm_gc_cells_swept
;
318 double local_scm_gc_cells_marked
;
320 unsigned long *bounds
= 0;
321 int table_size
= scm_i_heap_segment_table_size
;
322 SCM_CRITICAL_SECTION_START
;
325 temporarily store the numbers, so as not to cause GC.
328 bounds
= malloc (sizeof (int) * table_size
* 2);
331 for (i
= table_size
; i
--; )
333 bounds
[2*i
] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[0];
334 bounds
[2*i
+1] = (unsigned long)scm_i_heap_segment_table
[i
]->bounds
[1];
338 /* Below, we cons to produce the resulting list. We want a snapshot of
339 * the heap situation before consing.
341 local_scm_mtrigger
= scm_mtrigger
;
342 local_scm_mallocated
= scm_mallocated
;
343 local_scm_heap_size
= SCM_HEAP_SIZE
;
345 local_scm_cells_allocated
= scm_cells_allocated
;
347 local_scm_gc_time_taken
= scm_gc_time_taken
;
348 local_scm_gc_mark_time_taken
= scm_gc_mark_time_taken
;
349 local_scm_gc_times
= scm_gc_times
;
350 local_scm_gc_malloc_yield_percentage
= scm_gc_malloc_yield_percentage
;
351 local_scm_gc_cell_yield_percentage
= scm_gc_cell_yield_percentage
;
352 local_protected_obj_count
= protected_obj_count
;
353 local_scm_gc_cells_swept
=
354 (double) scm_gc_cells_swept_acc
355 + (double) scm_gc_cells_swept
;
356 local_scm_gc_cells_marked
= scm_gc_cells_marked_acc
357 +(double) scm_gc_cells_swept
358 -(double) scm_gc_cells_collected
;
360 for (i
= table_size
; i
--;)
362 heap_segs
= scm_cons (scm_cons (scm_from_ulong (bounds
[2*i
]),
363 scm_from_ulong (bounds
[2*i
+1])),
366 /* njrev: can any of these scm_cons's or scm_list_n signal a memory
367 error? If so we need a frame here. */
369 scm_list_n (scm_cons (sym_gc_time_taken
,
370 scm_from_ulong (local_scm_gc_time_taken
)),
371 scm_cons (sym_cells_allocated
,
372 scm_from_ulong (local_scm_cells_allocated
)),
373 scm_cons (sym_heap_size
,
374 scm_from_ulong (local_scm_heap_size
)),
375 scm_cons (sym_mallocated
,
376 scm_from_ulong (local_scm_mallocated
)),
377 scm_cons (sym_mtrigger
,
378 scm_from_ulong (local_scm_mtrigger
)),
380 scm_from_ulong (local_scm_gc_times
)),
381 scm_cons (sym_gc_mark_time_taken
,
382 scm_from_ulong (local_scm_gc_mark_time_taken
)),
383 scm_cons (sym_cells_marked
,
384 scm_from_double (local_scm_gc_cells_marked
)),
385 scm_cons (sym_cells_swept
,
386 scm_from_double (local_scm_gc_cells_swept
)),
387 scm_cons (sym_malloc_yield
,
388 scm_from_long(local_scm_gc_malloc_yield_percentage
)),
389 scm_cons (sym_cell_yield
,
390 scm_from_long (local_scm_gc_cell_yield_percentage
)),
391 scm_cons (sym_protected_objects
,
392 scm_from_ulong (local_protected_obj_count
)),
393 scm_cons (sym_heap_segments
, heap_segs
),
395 SCM_CRITICAL_SECTION_END
;
403 gc_start_stats (const char *what SCM_UNUSED
)
405 t_before_gc
= scm_c_get_internal_run_time ();
407 scm_gc_cells_marked_acc
+= (double) scm_gc_cells_swept
408 - (double) scm_gc_cells_collected
;
409 scm_gc_cells_swept_acc
+= (double) scm_gc_cells_swept
;
411 scm_gc_cell_yield_percentage
= ( scm_gc_cells_collected
* 100 ) / SCM_HEAP_SIZE
;
413 scm_gc_cells_swept
= 0;
414 scm_gc_cells_collected_1
= scm_gc_cells_collected
;
417 CELLS SWEPT is another word for the number of cells that were
418 examined during GC. YIELD is the number that we cleaned
419 out. MARKED is the number that weren't cleaned.
421 scm_gc_cells_collected
= 0;
422 scm_gc_malloc_collected
= 0;
423 scm_gc_ports_collected
= 0;
429 unsigned long t
= scm_c_get_internal_run_time ();
430 scm_gc_time_taken
+= (t
- t_before_gc
);
436 SCM_DEFINE (scm_object_address
, "object-address", 1, 0, 0,
438 "Return an integer that for the lifetime of @var{obj} is uniquely\n"
439 "returned by this function for @var{obj}")
440 #define FUNC_NAME s_scm_object_address
442 return scm_from_ulong (SCM_UNPACK (obj
));
447 SCM_DEFINE (scm_gc
, "gc", 0, 0, 0,
449 "Scans all of SCM objects and reclaims for further use those that are\n"
450 "no longer accessible.")
451 #define FUNC_NAME s_scm_gc
453 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
454 scm_gc_running_p
= 1;
456 /* njrev: It looks as though other places, e.g. scm_realloc,
457 can call scm_i_gc without acquiring the sweep mutex. Does this
458 matter? Also scm_i_gc (or its descendants) touch the
459 scm_sys_protects, which are protected in some cases
460 (e.g. scm_permobjs above in scm_gc_stats) by a critical section,
461 not by the sweep mutex. Shouldn't all the GC-relevant objects be
462 protected in the same way? */
463 scm_gc_running_p
= 0;
464 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
465 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
466 return SCM_UNSPECIFIED
;
473 /* The master is global and common while the freelist will be
474 * individual for each thread.
478 scm_gc_for_newcell (scm_t_cell_type_statistics
*freelist
, SCM
*free_cells
)
483 scm_i_scm_pthread_mutex_lock (&scm_i_sweep_mutex
);
484 scm_gc_running_p
= 1;
486 *free_cells
= scm_i_sweep_some_segments (freelist
);
487 if (*free_cells
== SCM_EOL
&& scm_i_gc_grow_heap_p (freelist
))
489 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
490 *free_cells
= scm_i_sweep_some_segments (freelist
);
493 if (*free_cells
== SCM_EOL
)
496 with the advent of lazy sweep, GC yield is only known just
499 scm_i_adjust_min_yield (freelist
);
502 out of fresh cells. Try to get some new ones.
508 *free_cells
= scm_i_sweep_some_segments (freelist
);
511 if (*free_cells
== SCM_EOL
)
514 failed getting new cells. Get new juice or die.
516 freelist
->heap_segment_idx
= scm_i_get_new_heap_segment (freelist
, abort_on_error
);
517 *free_cells
= scm_i_sweep_some_segments (freelist
);
520 if (*free_cells
== SCM_EOL
)
525 *free_cells
= SCM_FREE_CELL_CDR (cell
);
527 scm_gc_running_p
= 0;
528 scm_i_pthread_mutex_unlock (&scm_i_sweep_mutex
);
531 scm_c_hook_run (&scm_after_gc_c_hook
, 0);
537 scm_t_c_hook scm_before_gc_c_hook
;
538 scm_t_c_hook scm_before_mark_c_hook
;
539 scm_t_c_hook scm_before_sweep_c_hook
;
540 scm_t_c_hook scm_after_sweep_c_hook
;
541 scm_t_c_hook scm_after_gc_c_hook
;
543 /* Must be called while holding scm_i_sweep_mutex.
547 scm_i_gc (const char *what
)
549 scm_i_thread_put_to_sleep ();
551 scm_c_hook_run (&scm_before_gc_c_hook
, 0);
554 fprintf (stderr
,"gc reason %s\n", what
);
557 scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist
))
559 : (scm_is_null (*SCM_FREELIST_LOC (scm_i_freelist2
)) ? "o" : "m"));
562 gc_start_stats (what
);
565 Set freelists to NULL so scm_cons() always triggers gc, causing
566 the assertion above to fail.
568 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
569 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
572 Let's finish the sweep. The conservative GC might point into the
573 garbage, and marking that would create a mess.
575 scm_i_sweep_all_segments("GC");
576 if (scm_mallocated
< scm_i_deprecated_memory_return
)
578 /* The byte count of allocated objects has underflowed. This is
579 probably because you forgot to report the sizes of objects you
580 have allocated, by calling scm_done_malloc or some such. When
581 the GC freed them, it subtracted their size from
582 scm_mallocated, which underflowed. */
584 "scm_gc_sweep: Byte count of allocated objects has underflowed.\n"
585 "This is probably because the GC hasn't been correctly informed\n"
586 "about object sizes\n");
589 scm_mallocated
-= scm_i_deprecated_memory_return
;
594 scm_c_hook_run (&scm_before_mark_c_hook
, 0);
596 scm_gc_mark_time_taken
+= (scm_c_get_internal_run_time () - t_before_gc
);
600 TODO: the after_sweep hook should probably be moved to just before
601 the mark, since that's where the sweep is finished in lazy
604 MDJ 030219 <djurfeldt@nada.kth.se>: No, probably not. The
605 original meaning implied at least two things: that it would be
608 1. the freelist is re-initialized (no evaluation possible, though)
612 2. the heap is "fresh"
613 (it is well-defined what data is used and what is not)
615 Neither of these conditions would hold just before the mark phase.
617 Of course, the lazy sweeping has muddled the distinction between
618 scm_before_sweep_c_hook and scm_after_sweep_c_hook, but even if
619 there were no difference, it would still be useful to have two
620 distinct classes of hook functions since this can prevent some
621 bad interference when several modules adds gc hooks.
624 scm_c_hook_run (&scm_before_sweep_c_hook
, 0);
626 scm_c_hook_run (&scm_after_sweep_c_hook
, 0);
630 scm_i_thread_wake_up ();
633 For debugging purposes, you could do
634 scm_i_sweep_all_segments("debug"), but then the remains of the
635 cell aren't left to analyse.
640 /* {GC Protection Helper Functions}
645 * If within a function you need to protect one or more scheme objects from
646 * garbage collection, pass them as parameters to one of the
647 * scm_remember_upto_here* functions below. These functions don't do
648 * anything, but since the compiler does not know that they are actually
649 * no-ops, it will generate code that calls these functions with the given
650 * parameters. Therefore, you can be sure that the compiler will keep those
651 * scheme values alive (on the stack or in a register) up to the point where
652 * scm_remember_upto_here* is called. In other words, place the call to
653 * scm_remember_upto_here* _behind_ the last code in your function, that
654 * depends on the scheme object to exist.
656 * Example: We want to make sure that the string object str does not get
657 * garbage collected during the execution of 'some_function' in the code
658 * below, because otherwise the characters belonging to str would be freed and
659 * 'some_function' might access freed memory. To make sure that the compiler
660 * keeps str alive on the stack or in a register such that it is visible to
661 * the conservative gc we add the call to scm_remember_upto_here_1 _after_ the
662 * call to 'some_function'. Note that this would not be necessary if str was
663 * used anyway after the call to 'some_function'.
664 * char *chars = scm_i_string_chars (str);
665 * some_function (chars);
666 * scm_remember_upto_here_1 (str); // str will be alive up to this point.
669 /* Remove any macro versions of these while defining the functions.
670 Functions are always included in the library, for upward binary
671 compatibility and in case combinations of GCC and non-GCC are used. */
672 #undef scm_remember_upto_here_1
673 #undef scm_remember_upto_here_2
676 scm_remember_upto_here_1 (SCM obj SCM_UNUSED
)
678 /* Empty. Protects a single object from garbage collection. */
682 scm_remember_upto_here_2 (SCM obj1 SCM_UNUSED
, SCM obj2 SCM_UNUSED
)
684 /* Empty. Protects two objects from garbage collection. */
688 scm_remember_upto_here (SCM obj SCM_UNUSED
, ...)
690 /* Empty. Protects any number of objects from garbage collection. */
694 These crazy functions prevent garbage collection
695 of arguments after the first argument by
696 ensuring they remain live throughout the
697 function because they are used in the last
698 line of the code block.
699 It'd be better to have a nice compiler hint to
700 aid the conservative stack-scanning GC. --03/09/00 gjb */
702 scm_return_first (SCM elt
, ...)
708 scm_return_first_int (int i
, ...)
715 scm_permanent_object (SCM obj
)
717 SCM cell
= scm_cons (obj
, SCM_EOL
);
718 SCM_CRITICAL_SECTION_START
;
719 SCM_SETCDR (cell
, scm_permobjs
);
721 SCM_CRITICAL_SECTION_END
;
726 /* Protect OBJ from the garbage collector. OBJ will not be freed, even if all
727 other references are dropped, until the object is unprotected by calling
728 scm_gc_unprotect_object (OBJ). Calls to scm_gc_protect/unprotect_object nest,
729 i. e. it is possible to protect the same object several times, but it is
730 necessary to unprotect the object the same number of times to actually get
731 the object unprotected. It is an error to unprotect an object more often
732 than it has been protected before. The function scm_protect_object returns
736 /* Implementation note: For every object X, there is a counter which
737 scm_gc_protect_object(X) increments and scm_gc_unprotect_object(X) decrements.
743 scm_gc_protect_object (SCM obj
)
747 /* This critical section barrier will be replaced by a mutex. */
748 /* njrev: Indeed; if my comment above is correct, there is the same
749 critsec/mutex inconsistency here. */
750 SCM_CRITICAL_SECTION_START
;
752 handle
= scm_hashq_create_handle_x (scm_protects
, obj
, scm_from_int (0));
753 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
755 protected_obj_count
++;
757 SCM_CRITICAL_SECTION_END
;
763 /* Remove any protection for OBJ established by a prior call to
764 scm_protect_object. This function returns OBJ.
766 See scm_protect_object for more information. */
768 scm_gc_unprotect_object (SCM obj
)
772 /* This critical section barrier will be replaced by a mutex. */
773 /* njrev: and again. */
774 SCM_CRITICAL_SECTION_START
;
776 if (scm_gc_running_p
)
778 fprintf (stderr
, "scm_unprotect_object called during GC.\n");
782 handle
= scm_hashq_get_handle (scm_protects
, obj
);
784 if (scm_is_false (handle
))
786 fprintf (stderr
, "scm_unprotect_object called on unprotected object\n");
791 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
792 if (scm_is_eq (count
, scm_from_int (0)))
793 scm_hashq_remove_x (scm_protects
, obj
);
795 SCM_SETCDR (handle
, count
);
797 protected_obj_count
--;
799 SCM_CRITICAL_SECTION_END
;
805 scm_gc_register_root (SCM
*p
)
808 SCM key
= scm_from_ulong ((unsigned long) p
);
810 /* This critical section barrier will be replaced by a mutex. */
811 /* njrev: and again. */
812 SCM_CRITICAL_SECTION_START
;
814 handle
= scm_hashv_create_handle_x (scm_gc_registered_roots
, key
,
816 /* njrev: note also that the above can probably signal an error */
817 SCM_SETCDR (handle
, scm_sum (SCM_CDR (handle
), scm_from_int (1)));
819 SCM_CRITICAL_SECTION_END
;
823 scm_gc_unregister_root (SCM
*p
)
826 SCM key
= scm_from_ulong ((unsigned long) p
);
828 /* This critical section barrier will be replaced by a mutex. */
829 /* njrev: and again. */
830 SCM_CRITICAL_SECTION_START
;
832 handle
= scm_hashv_get_handle (scm_gc_registered_roots
, key
);
834 if (scm_is_false (handle
))
836 fprintf (stderr
, "scm_gc_unregister_root called on unregistered root\n");
841 SCM count
= scm_difference (SCM_CDR (handle
), scm_from_int (1));
842 if (scm_is_eq (count
, scm_from_int (0)))
843 scm_hashv_remove_x (scm_gc_registered_roots
, key
);
845 SCM_SETCDR (handle
, count
);
848 SCM_CRITICAL_SECTION_END
;
852 scm_gc_register_roots (SCM
*b
, unsigned long n
)
855 for (; p
< b
+ n
; ++p
)
856 scm_gc_register_root (p
);
860 scm_gc_unregister_roots (SCM
*b
, unsigned long n
)
863 for (; p
< b
+ n
; ++p
)
864 scm_gc_unregister_root (p
);
867 int scm_i_terminating
;
873 MOVE THIS FUNCTION. IT DOES NOT HAVE ANYTHING TODO WITH GC.
876 /* Get an integer from an environment variable. */
878 scm_getenv_int (const char *var
, int def
)
881 char *val
= getenv (var
);
885 res
= strtol (val
, &end
, 10);
892 scm_storage_prehistory ()
894 scm_c_hook_init (&scm_before_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
895 scm_c_hook_init (&scm_before_mark_c_hook
, 0, SCM_C_HOOK_NORMAL
);
896 scm_c_hook_init (&scm_before_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
897 scm_c_hook_init (&scm_after_sweep_c_hook
, 0, SCM_C_HOOK_NORMAL
);
898 scm_c_hook_init (&scm_after_gc_c_hook
, 0, SCM_C_HOOK_NORMAL
);
901 scm_i_pthread_mutex_t scm_i_gc_admin_mutex
= SCM_I_PTHREAD_MUTEX_INITIALIZER
;
908 j
= SCM_NUM_PROTECTS
;
910 scm_sys_protects
[--j
] = SCM_BOOL_F
;
912 scm_gc_init_freelist();
913 scm_gc_init_malloc ();
915 j
= SCM_HEAP_SEG_SIZE
;
918 /* Initialise the list of ports. */
919 scm_i_port_table
= (scm_t_port
**)
920 malloc (sizeof (scm_t_port
*) * scm_i_port_table_room
);
921 if (!scm_i_port_table
)
925 /* We can't have a cleanup handler since we have no thread to run it
932 on_exit (cleanup
, 0);
938 scm_stand_in_procs
= scm_make_weak_key_hash_table (scm_from_int (257));
939 scm_permobjs
= SCM_EOL
;
940 scm_protects
= scm_c_make_hash_table (31);
941 scm_gc_registered_roots
= scm_c_make_hash_table (31);
948 SCM scm_after_gc_hook
;
952 /* The function gc_async_thunk causes the execution of the after-gc-hook. It
953 * is run after the gc, as soon as the asynchronous events are handled by the
957 gc_async_thunk (void)
959 scm_c_run_hook (scm_after_gc_hook
, SCM_EOL
);
960 return SCM_UNSPECIFIED
;
964 /* The function mark_gc_async is run by the scm_after_gc_c_hook at the end of
965 * the garbage collection. The only purpose of this function is to mark the
966 * gc_async (which will eventually lead to the execution of the
970 mark_gc_async (void * hook_data SCM_UNUSED
,
971 void *func_data SCM_UNUSED
,
972 void *data SCM_UNUSED
)
974 /* If cell access debugging is enabled, the user may choose to perform
975 * additional garbage collections after an arbitrary number of cell
976 * accesses. We don't want the scheme level after-gc-hook to be performed
977 * for each of these garbage collections for the following reason: The
978 * execution of the after-gc-hook causes cell accesses itself. Thus, if the
979 * after-gc-hook was performed with every gc, and if the gc was performed
980 * after a very small number of cell accesses, then the number of cell
981 * accesses during the execution of the after-gc-hook will suffice to cause
982 * the execution of the next gc. Then, guile would keep executing the
983 * after-gc-hook over and over again, and would never come to do other
986 * To overcome this problem, if cell access debugging with additional
987 * garbage collections is enabled, the after-gc-hook is never run by the
988 * garbage collecter. When running guile with cell access debugging and the
989 * execution of the after-gc-hook is desired, then it is necessary to run
990 * the hook explicitly from the user code. This has the effect, that from
991 * the scheme level point of view it seems that garbage collection is
992 * performed with a much lower frequency than it actually is. Obviously,
993 * this will not work for code that depends on a fixed one to one
994 * relationship between the execution counts of the C level garbage
995 * collection hooks and the execution count of the scheme level
999 #if (SCM_DEBUG_CELL_ACCESSES == 1)
1000 if (scm_debug_cells_gc_interval
== 0)
1001 scm_system_async_mark (gc_async
);
1003 scm_system_async_mark (gc_async
);
1012 scm_gc_init_mark ();
1014 scm_after_gc_hook
= scm_permanent_object (scm_make_hook (SCM_INUM0
));
1015 scm_c_define ("after-gc-hook", scm_after_gc_hook
);
1017 gc_async
= scm_c_make_subr ("%gc-thunk", scm_tc7_subr_0
,
1020 scm_c_hook_add (&scm_after_gc_c_hook
, mark_gc_async
, NULL
, 0);
1022 #include "libguile/gc.x"
1028 #define FUNC_NAME "scm_gc_sweep"
1030 scm_i_deprecated_memory_return
= 0;
1032 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist
);
1033 scm_i_gc_sweep_freelist_reset (&scm_i_master_freelist2
);
1036 NOTHING HERE: LAZY SWEEPING !
1038 scm_i_reset_segments ();
1040 *SCM_FREELIST_LOC (scm_i_freelist
) = SCM_EOL
;
1041 *SCM_FREELIST_LOC (scm_i_freelist2
) = SCM_EOL
;
1043 /* Invalidate the freelists of other threads. */
1044 scm_i_thread_invalidate_freelists ();