2 * GENerational Conservative Garbage Collector for SBCL
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 * For a review of garbage collection techniques (e.g. generational
18 * GC) and terminology (e.g. "scavenging") see Paul R. Wilson,
19 * "Uniprocessor Garbage Collection Techniques". As of 20000618, this
20 * had been accepted for _ACM Computing Surveys_ and was available
21 * as a PostScript preprint through
22 * <http://www.cs.utexas.edu/users/oops/papers.html>
24 * <ftp://ftp.cs.utexas.edu/pub/garbage/bigsurv.ps>.
37 #include "interrupt.h"
43 #include "gc-internal.h"
46 #include "genesis/vector.h"
47 #include "genesis/weak-pointer.h"
48 #include "genesis/fdefn.h"
49 #include "genesis/simple-fun.h"
51 #include "genesis/hash-table.h"
52 #include "genesis/instance.h"
53 #include "genesis/layout.h"
55 #if defined(LUTEX_WIDETAG)
56 #include "pthread-lutex.h"
59 /* forward declarations */
60 page_index_t
gc_find_freeish_pages(long *restart_page_ptr
, long nbytes
,
68 /* Generations 0-5 are normal collected generations, 6 is only used as
69 * scratch space by the collector, and should never get collected.
72 HIGHEST_NORMAL_GENERATION
= 5,
73 PSEUDO_STATIC_GENERATION
,
78 /* Should we use page protection to help avoid the scavenging of pages
79 * that don't have pointers to younger generations? */
80 boolean enable_page_protection
= 1;
82 /* the minimum size (in bytes) for a large object*/
83 unsigned long large_object_size
= 4 * PAGE_BYTES
;
90 /* the verbosity level. All non-error messages are disabled at level 0;
91 * and only a few rare messages are printed at level 1. */
93 boolean gencgc_verbose
= 1;
95 boolean gencgc_verbose
= 0;
98 /* FIXME: At some point enable the various error-checking things below
99 * and see what they say. */
101 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
102 * Set verify_gens to HIGHEST_NORMAL_GENERATION + 1 to disable this kind of
104 generation_index_t verify_gens
= HIGHEST_NORMAL_GENERATION
+ 1;
106 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
107 boolean pre_verify_gen_0
= 0;
109 /* Should we check for bad pointers after gc_free_heap is called
110 * from Lisp PURIFY? */
111 boolean verify_after_free_heap
= 0;
113 /* Should we print a note when code objects are found in the dynamic space
114 * during a heap verify? */
115 boolean verify_dynamic_code_check
= 0;
117 /* Should we check code objects for fixup errors after they are transported? */
118 boolean check_code_fixups
= 0;
120 /* Should we check that newly allocated regions are zero filled? */
121 boolean gencgc_zero_check
= 0;
123 /* Should we check that the free space is zero filled? */
124 boolean gencgc_enable_verify_zero_fill
= 0;
126 /* Should we check that free pages are zero filled during gc_free_heap
127 * called after Lisp PURIFY? */
128 boolean gencgc_zero_check_during_free_heap
= 0;
130 /* When loading a core, don't do a full scan of the memory for the
131 * memory region boundaries. (Set to true by coreparse.c if the core
132 * contained a pagetable entry).
134 boolean gencgc_partial_pickup
= 0;
136 /* If defined, free pages are read-protected to ensure that nothing
140 /* #define READ_PROTECT_FREE_PAGES */
144 * GC structures and variables
147 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
148 unsigned long bytes_allocated
= 0;
149 unsigned long auto_gc_trigger
= 0;
151 /* the source and destination generations. These are set before a GC starts
153 generation_index_t from_space
;
154 generation_index_t new_space
;
156 /* Set to 1 when in GC */
157 boolean gc_active_p
= 0;
159 /* should the GC be conservative on stack. If false (only right before
160 * saving a core), don't scan the stack / mark pages dont_move. */
161 static boolean conservative_stack
= 1;
163 /* An array of page structures is allocated on gc initialization.
164 * This helps quickly map between an address its page structure.
165 * page_table_pages is set from the size of the dynamic space. */
166 unsigned page_table_pages
;
167 struct page
*page_table
;
169 /* To map addresses to page structures the address of the first page
171 static void *heap_base
= NULL
;
173 /* Calculate the start address for the given page number. */
175 page_address(page_index_t page_num
)
177 return (heap_base
+ (page_num
* PAGE_BYTES
));
180 /* Find the page index within the page_table for the given
181 * address. Return -1 on failure. */
183 find_page_index(void *addr
)
185 page_index_t index
= addr
-heap_base
;
188 index
= ((unsigned long)index
)/PAGE_BYTES
;
189 if (index
< page_table_pages
)
196 /* a structure to hold the state of a generation */
199 /* the first page that gc_alloc() checks on its next call */
200 page_index_t alloc_start_page
;
202 /* the first page that gc_alloc_unboxed() checks on its next call */
203 page_index_t alloc_unboxed_start_page
;
205 /* the first page that gc_alloc_large (boxed) considers on its next
206 * call. (Although it always allocates after the boxed_region.) */
207 page_index_t alloc_large_start_page
;
209 /* the first page that gc_alloc_large (unboxed) considers on its
210 * next call. (Although it always allocates after the
211 * current_unboxed_region.) */
212 page_index_t alloc_large_unboxed_start_page
;
214 /* the bytes allocated to this generation */
215 long bytes_allocated
;
217 /* the number of bytes at which to trigger a GC */
220 /* to calculate a new level for gc_trigger */
221 long bytes_consed_between_gc
;
223 /* the number of GCs since the last raise */
226 /* the average age after which a GC will raise objects to the
230 /* the cumulative sum of the bytes allocated to this generation. It is
231 * cleared after a GC on this generations, and update before new
232 * objects are added from a GC of a younger generation. Dividing by
233 * the bytes_allocated will give the average age of the memory in
234 * this generation since its last GC. */
235 long cum_sum_bytes_allocated
;
237 /* a minimum average memory age before a GC will occur helps
238 * prevent a GC when a large number of new live objects have been
239 * added, in which case a GC could be a waste of time */
240 double min_av_mem_age
;
242 /* A linked list of lutex structures in this generation, used for
243 * implementing lutex finalization. */
245 struct lutex
*lutexes
;
251 /* an array of generation structures. There needs to be one more
252 * generation structure than actual generations as the oldest
253 * generation is temporarily raised then lowered. */
254 struct generation generations
[NUM_GENERATIONS
];
256 /* the oldest generation that is will currently be GCed by default.
257 * Valid values are: 0, 1, ... HIGHEST_NORMAL_GENERATION
259 * The default of HIGHEST_NORMAL_GENERATION enables GC on all generations.
261 * Setting this to 0 effectively disables the generational nature of
262 * the GC. In some applications generational GC may not be useful
263 * because there are no long-lived objects.
265 * An intermediate value could be handy after moving long-lived data
266 * into an older generation so an unnecessary GC of this long-lived
267 * data can be avoided. */
268 generation_index_t gencgc_oldest_gen_to_gc
= HIGHEST_NORMAL_GENERATION
;
270 /* The maximum free page in the heap is maintained and used to update
271 * ALLOCATION_POINTER which is used by the room function to limit its
272 * search of the heap. XX Gencgc obviously needs to be better
273 * integrated with the Lisp code. */
274 page_index_t last_free_page
;
276 /* This lock is to prevent multiple threads from simultaneously
277 * allocating new regions which overlap each other. Note that the
278 * majority of GC is single-threaded, but alloc() may be called from
279 * >1 thread at a time and must be thread-safe. This lock must be
280 * seized before all accesses to generations[] or to parts of
281 * page_table[] that other threads may want to see */
283 #ifdef LISP_FEATURE_SB_THREAD
284 static pthread_mutex_t free_pages_lock
= PTHREAD_MUTEX_INITIALIZER
;
289 * miscellaneous heap functions
292 /* Count the number of pages which are write-protected within the
293 * given generation. */
295 count_write_protect_generation_pages(generation_index_t generation
)
300 for (i
= 0; i
< last_free_page
; i
++)
301 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
302 && (page_table
[i
].gen
== generation
)
303 && (page_table
[i
].write_protected
== 1))
308 /* Count the number of pages within the given generation. */
310 count_generation_pages(generation_index_t generation
)
315 for (i
= 0; i
< last_free_page
; i
++)
316 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
317 && (page_table
[i
].gen
== generation
))
324 count_dont_move_pages(void)
328 for (i
= 0; i
< last_free_page
; i
++) {
329 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
330 && (page_table
[i
].dont_move
!= 0)) {
338 /* Work through the pages and add up the number of bytes used for the
339 * given generation. */
341 count_generation_bytes_allocated (generation_index_t gen
)
345 for (i
= 0; i
< last_free_page
; i
++) {
346 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
347 && (page_table
[i
].gen
== gen
))
348 result
+= page_table
[i
].bytes_used
;
353 /* Return the average age of the memory in a generation. */
355 gen_av_mem_age(generation_index_t gen
)
357 if (generations
[gen
].bytes_allocated
== 0)
361 ((double)generations
[gen
].cum_sum_bytes_allocated
)
362 / ((double)generations
[gen
].bytes_allocated
);
365 /* The verbose argument controls how much to print: 0 for normal
366 * level of detail; 1 for debugging. */
368 print_generation_stats(int verbose
) /* FIXME: should take FILE argument */
370 generation_index_t i
, gens
;
372 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
373 #define FPU_STATE_SIZE 27
374 int fpu_state
[FPU_STATE_SIZE
];
375 #elif defined(LISP_FEATURE_PPC)
376 #define FPU_STATE_SIZE 32
377 long long fpu_state
[FPU_STATE_SIZE
];
380 /* This code uses the FP instructions which may be set up for Lisp
381 * so they need to be saved and reset for C. */
384 /* highest generation to print */
386 gens
= SCRATCH_GENERATION
;
388 gens
= PSEUDO_STATIC_GENERATION
;
390 /* Print the heap stats. */
392 " Gen StaPg UbSta LaSta LUbSt Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
394 for (i
= 0; i
< gens
; i
++) {
397 long unboxed_cnt
= 0;
398 long large_boxed_cnt
= 0;
399 long large_unboxed_cnt
= 0;
402 for (j
= 0; j
< last_free_page
; j
++)
403 if (page_table
[j
].gen
== i
) {
405 /* Count the number of boxed pages within the given
407 if (page_table
[j
].allocated
& BOXED_PAGE_FLAG
) {
408 if (page_table
[j
].large_object
)
413 if(page_table
[j
].dont_move
) pinned_cnt
++;
414 /* Count the number of unboxed pages within the given
416 if (page_table
[j
].allocated
& UNBOXED_PAGE_FLAG
) {
417 if (page_table
[j
].large_object
)
424 gc_assert(generations
[i
].bytes_allocated
425 == count_generation_bytes_allocated(i
));
427 " %1d: %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %8ld %5ld %8ld %4ld %3d %7.4f\n",
429 generations
[i
].alloc_start_page
,
430 generations
[i
].alloc_unboxed_start_page
,
431 generations
[i
].alloc_large_start_page
,
432 generations
[i
].alloc_large_unboxed_start_page
,
438 generations
[i
].bytes_allocated
,
439 (count_generation_pages(i
)*PAGE_BYTES
- generations
[i
].bytes_allocated
),
440 generations
[i
].gc_trigger
,
441 count_write_protect_generation_pages(i
),
442 generations
[i
].num_gc
,
445 fprintf(stderr
," Total bytes allocated=%ld\n", bytes_allocated
);
447 fpu_restore(fpu_state
);
451 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
452 void fast_bzero(void*, size_t); /* in <arch>-assem.S */
455 /* Zero the pages from START to END (inclusive), but use mmap/munmap instead
456 * if zeroing it ourselves, i.e. in practice give the memory back to the
457 * OS. Generally done after a large GC.
459 void zero_pages_with_mmap(page_index_t start
, page_index_t end
) {
461 void *addr
= (void *) page_address(start
), *new_addr
;
462 size_t length
= PAGE_BYTES
*(1+end
-start
);
467 os_invalidate(addr
, length
);
468 new_addr
= os_validate(addr
, length
);
469 if (new_addr
== NULL
|| new_addr
!= addr
) {
470 lose("remap_free_pages: page moved, 0x%08x ==> 0x%08x", start
, new_addr
);
473 for (i
= start
; i
<= end
; i
++) {
474 page_table
[i
].need_to_zero
= 0;
478 /* Zero the pages from START to END (inclusive). Generally done just after
479 * a new region has been allocated.
482 zero_pages(page_index_t start
, page_index_t end
) {
486 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
487 fast_bzero(page_address(start
), PAGE_BYTES
*(1+end
-start
));
489 bzero(page_address(start
), PAGE_BYTES
*(1+end
-start
));
494 /* Zero the pages from START to END (inclusive), except for those
495 * pages that are known to already zeroed. Mark all pages in the
496 * ranges as non-zeroed.
499 zero_dirty_pages(page_index_t start
, page_index_t end
) {
502 for (i
= start
; i
<= end
; i
++) {
503 if (page_table
[i
].need_to_zero
== 1) {
504 zero_pages(start
, end
);
509 for (i
= start
; i
<= end
; i
++) {
510 page_table
[i
].need_to_zero
= 1;
516 * To support quick and inline allocation, regions of memory can be
517 * allocated and then allocated from with just a free pointer and a
518 * check against an end address.
520 * Since objects can be allocated to spaces with different properties
521 * e.g. boxed/unboxed, generation, ages; there may need to be many
522 * allocation regions.
524 * Each allocation region may start within a partly used page. Many
525 * features of memory use are noted on a page wise basis, e.g. the
526 * generation; so if a region starts within an existing allocated page
527 * it must be consistent with this page.
529 * During the scavenging of the newspace, objects will be transported
530 * into an allocation region, and pointers updated to point to this
531 * allocation region. It is possible that these pointers will be
532 * scavenged again before the allocation region is closed, e.g. due to
533 * trans_list which jumps all over the place to cleanup the list. It
534 * is important to be able to determine properties of all objects
535 * pointed to when scavenging, e.g to detect pointers to the oldspace.
536 * Thus it's important that the allocation regions have the correct
537 * properties set when allocated, and not just set when closed. The
538 * region allocation routines return regions with the specified
539 * properties, and grab all the pages, setting their properties
540 * appropriately, except that the amount used is not known.
542 * These regions are used to support quicker allocation using just a
543 * free pointer. The actual space used by the region is not reflected
544 * in the pages tables until it is closed. It can't be scavenged until
547 * When finished with the region it should be closed, which will
548 * update the page tables for the actual space used returning unused
549 * space. Further it may be noted in the new regions which is
550 * necessary when scavenging the newspace.
552 * Large objects may be allocated directly without an allocation
553 * region, the page tables are updated immediately.
555 * Unboxed objects don't contain pointers to other objects and so
556 * don't need scavenging. Further they can't contain pointers to
557 * younger generations so WP is not needed. By allocating pages to
558 * unboxed objects the whole page never needs scavenging or
559 * write-protecting. */
561 /* We are only using two regions at present. Both are for the current
562 * newspace generation. */
563 struct alloc_region boxed_region
;
564 struct alloc_region unboxed_region
;
566 /* The generation currently being allocated to. */
567 static generation_index_t gc_alloc_generation
;
569 /* Find a new region with room for at least the given number of bytes.
571 * It starts looking at the current generation's alloc_start_page. So
572 * may pick up from the previous region if there is enough space. This
573 * keeps the allocation contiguous when scavenging the newspace.
575 * The alloc_region should have been closed by a call to
576 * gc_alloc_update_page_tables(), and will thus be in an empty state.
578 * To assist the scavenging functions write-protected pages are not
579 * used. Free pages should not be write-protected.
581 * It is critical to the conservative GC that the start of regions be
582 * known. To help achieve this only small regions are allocated at a
585 * During scavenging, pointers may be found to within the current
586 * region and the page generation must be set so that pointers to the
587 * from space can be recognized. Therefore the generation of pages in
588 * the region are set to gc_alloc_generation. To prevent another
589 * allocation call using the same pages, all the pages in the region
590 * are allocated, although they will initially be empty.
593 gc_alloc_new_region(long nbytes
, int unboxed
, struct alloc_region
*alloc_region
)
595 page_index_t first_page
;
596 page_index_t last_page
;
603 "/alloc_new_region for %d bytes from gen %d\n",
604 nbytes, gc_alloc_generation));
607 /* Check that the region is in a reset state. */
608 gc_assert((alloc_region
->first_page
== 0)
609 && (alloc_region
->last_page
== -1)
610 && (alloc_region
->free_pointer
== alloc_region
->end_addr
));
611 ret
= thread_mutex_lock(&free_pages_lock
);
615 generations
[gc_alloc_generation
].alloc_unboxed_start_page
;
618 generations
[gc_alloc_generation
].alloc_start_page
;
620 last_page
=gc_find_freeish_pages(&first_page
,nbytes
,unboxed
);
621 bytes_found
=(PAGE_BYTES
- page_table
[first_page
].bytes_used
)
622 + PAGE_BYTES
*(last_page
-first_page
);
624 /* Set up the alloc_region. */
625 alloc_region
->first_page
= first_page
;
626 alloc_region
->last_page
= last_page
;
627 alloc_region
->start_addr
= page_table
[first_page
].bytes_used
628 + page_address(first_page
);
629 alloc_region
->free_pointer
= alloc_region
->start_addr
;
630 alloc_region
->end_addr
= alloc_region
->start_addr
+ bytes_found
;
632 /* Set up the pages. */
634 /* The first page may have already been in use. */
635 if (page_table
[first_page
].bytes_used
== 0) {
637 page_table
[first_page
].allocated
= UNBOXED_PAGE_FLAG
;
639 page_table
[first_page
].allocated
= BOXED_PAGE_FLAG
;
640 page_table
[first_page
].gen
= gc_alloc_generation
;
641 page_table
[first_page
].large_object
= 0;
642 page_table
[first_page
].first_object_offset
= 0;
646 gc_assert(page_table
[first_page
].allocated
== UNBOXED_PAGE_FLAG
);
648 gc_assert(page_table
[first_page
].allocated
== BOXED_PAGE_FLAG
);
649 page_table
[first_page
].allocated
|= OPEN_REGION_PAGE_FLAG
;
651 gc_assert(page_table
[first_page
].gen
== gc_alloc_generation
);
652 gc_assert(page_table
[first_page
].large_object
== 0);
654 for (i
= first_page
+1; i
<= last_page
; i
++) {
656 page_table
[i
].allocated
= UNBOXED_PAGE_FLAG
;
658 page_table
[i
].allocated
= BOXED_PAGE_FLAG
;
659 page_table
[i
].gen
= gc_alloc_generation
;
660 page_table
[i
].large_object
= 0;
661 /* This may not be necessary for unboxed regions (think it was
663 page_table
[i
].first_object_offset
=
664 alloc_region
->start_addr
- page_address(i
);
665 page_table
[i
].allocated
|= OPEN_REGION_PAGE_FLAG
;
667 /* Bump up last_free_page. */
668 if (last_page
+1 > last_free_page
) {
669 last_free_page
= last_page
+1;
670 /* do we only want to call this on special occasions? like for boxed_region? */
671 set_alloc_pointer((lispobj
)(((char *)heap_base
) + last_free_page
*PAGE_BYTES
));
673 ret
= thread_mutex_unlock(&free_pages_lock
);
676 /* we can do this after releasing free_pages_lock */
677 if (gencgc_zero_check
) {
679 for (p
= (long *)alloc_region
->start_addr
;
680 p
< (long *)alloc_region
->end_addr
; p
++) {
682 /* KLUDGE: It would be nice to use %lx and explicit casts
683 * (long) in code like this, so that it is less likely to
684 * break randomly when running on a machine with different
685 * word sizes. -- WHN 19991129 */
686 lose("The new region at %x is not zero.\n", p
);
691 #ifdef READ_PROTECT_FREE_PAGES
692 os_protect(page_address(first_page
),
693 PAGE_BYTES
*(1+last_page
-first_page
),
697 /* If the first page was only partial, don't check whether it's
698 * zeroed (it won't be) and don't zero it (since the parts that
699 * we're interested in are guaranteed to be zeroed).
701 if (page_table
[first_page
].bytes_used
) {
705 zero_dirty_pages(first_page
, last_page
);
708 /* If the record_new_objects flag is 2 then all new regions created
711 * If it's 1 then then it is only recorded if the first page of the
712 * current region is <= new_areas_ignore_page. This helps avoid
713 * unnecessary recording when doing full scavenge pass.
715 * The new_object structure holds the page, byte offset, and size of
716 * new regions of objects. Each new area is placed in the array of
717 * these structures pointer to by new_areas. new_areas_index holds the
718 * offset into new_areas.
720 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
721 * later code must detect this and handle it, probably by doing a full
722 * scavenge of a generation. */
723 #define NUM_NEW_AREAS 512
724 static int record_new_objects
= 0;
725 static page_index_t new_areas_ignore_page
;
731 static struct new_area (*new_areas
)[];
732 static long new_areas_index
;
735 /* Add a new area to new_areas. */
737 add_new_area(page_index_t first_page
, long offset
, long size
)
739 unsigned long new_area_start
,c
;
742 /* Ignore if full. */
743 if (new_areas_index
>= NUM_NEW_AREAS
)
746 switch (record_new_objects
) {
750 if (first_page
> new_areas_ignore_page
)
759 new_area_start
= PAGE_BYTES
*first_page
+ offset
;
761 /* Search backwards for a prior area that this follows from. If
762 found this will save adding a new area. */
763 for (i
= new_areas_index
-1, c
= 0; (i
>= 0) && (c
< 8); i
--, c
++) {
764 unsigned long area_end
=
765 PAGE_BYTES
*((*new_areas
)[i
].page
)
766 + (*new_areas
)[i
].offset
767 + (*new_areas
)[i
].size
;
769 "/add_new_area S1 %d %d %d %d\n",
770 i, c, new_area_start, area_end));*/
771 if (new_area_start
== area_end
) {
773 "/adding to [%d] %d %d %d with %d %d %d:\n",
775 (*new_areas)[i].page,
776 (*new_areas)[i].offset,
777 (*new_areas)[i].size,
781 (*new_areas
)[i
].size
+= size
;
786 (*new_areas
)[new_areas_index
].page
= first_page
;
787 (*new_areas
)[new_areas_index
].offset
= offset
;
788 (*new_areas
)[new_areas_index
].size
= size
;
790 "/new_area %d page %d offset %d size %d\n",
791 new_areas_index, first_page, offset, size));*/
794 /* Note the max new_areas used. */
795 if (new_areas_index
> max_new_areas
)
796 max_new_areas
= new_areas_index
;
799 /* Update the tables for the alloc_region. The region may be added to
802 * When done the alloc_region is set up so that the next quick alloc
803 * will fail safely and thus a new region will be allocated. Further
804 * it is safe to try to re-update the page table of this reset
807 gc_alloc_update_page_tables(int unboxed
, struct alloc_region
*alloc_region
)
810 page_index_t first_page
;
811 page_index_t next_page
;
813 long orig_first_page_bytes_used
;
819 first_page
= alloc_region
->first_page
;
821 /* Catch an unused alloc_region. */
822 if ((first_page
== 0) && (alloc_region
->last_page
== -1))
825 next_page
= first_page
+1;
827 ret
= thread_mutex_lock(&free_pages_lock
);
829 if (alloc_region
->free_pointer
!= alloc_region
->start_addr
) {
830 /* some bytes were allocated in the region */
831 orig_first_page_bytes_used
= page_table
[first_page
].bytes_used
;
833 gc_assert(alloc_region
->start_addr
== (page_address(first_page
) + page_table
[first_page
].bytes_used
));
835 /* All the pages used need to be updated */
837 /* Update the first page. */
839 /* If the page was free then set up the gen, and
840 * first_object_offset. */
841 if (page_table
[first_page
].bytes_used
== 0)
842 gc_assert(page_table
[first_page
].first_object_offset
== 0);
843 page_table
[first_page
].allocated
&= ~(OPEN_REGION_PAGE_FLAG
);
846 gc_assert(page_table
[first_page
].allocated
== UNBOXED_PAGE_FLAG
);
848 gc_assert(page_table
[first_page
].allocated
== BOXED_PAGE_FLAG
);
849 gc_assert(page_table
[first_page
].gen
== gc_alloc_generation
);
850 gc_assert(page_table
[first_page
].large_object
== 0);
854 /* Calculate the number of bytes used in this page. This is not
855 * always the number of new bytes, unless it was free. */
857 if ((bytes_used
= (alloc_region
->free_pointer
- page_address(first_page
)))>PAGE_BYTES
) {
858 bytes_used
= PAGE_BYTES
;
861 page_table
[first_page
].bytes_used
= bytes_used
;
862 byte_cnt
+= bytes_used
;
865 /* All the rest of the pages should be free. We need to set their
866 * first_object_offset pointer to the start of the region, and set
869 page_table
[next_page
].allocated
&= ~(OPEN_REGION_PAGE_FLAG
);
871 gc_assert(page_table
[next_page
].allocated
==UNBOXED_PAGE_FLAG
);
873 gc_assert(page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
);
874 gc_assert(page_table
[next_page
].bytes_used
== 0);
875 gc_assert(page_table
[next_page
].gen
== gc_alloc_generation
);
876 gc_assert(page_table
[next_page
].large_object
== 0);
878 gc_assert(page_table
[next_page
].first_object_offset
==
879 alloc_region
->start_addr
- page_address(next_page
));
881 /* Calculate the number of bytes used in this page. */
883 if ((bytes_used
= (alloc_region
->free_pointer
884 - page_address(next_page
)))>PAGE_BYTES
) {
885 bytes_used
= PAGE_BYTES
;
888 page_table
[next_page
].bytes_used
= bytes_used
;
889 byte_cnt
+= bytes_used
;
894 region_size
= alloc_region
->free_pointer
- alloc_region
->start_addr
;
895 bytes_allocated
+= region_size
;
896 generations
[gc_alloc_generation
].bytes_allocated
+= region_size
;
898 gc_assert((byte_cnt
- orig_first_page_bytes_used
) == region_size
);
900 /* Set the generations alloc restart page to the last page of
903 generations
[gc_alloc_generation
].alloc_unboxed_start_page
=
906 generations
[gc_alloc_generation
].alloc_start_page
= next_page
-1;
908 /* Add the region to the new_areas if requested. */
910 add_new_area(first_page
,orig_first_page_bytes_used
, region_size
);
914 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
916 gc_alloc_generation));
919 /* There are no bytes allocated. Unallocate the first_page if
920 * there are 0 bytes_used. */
921 page_table
[first_page
].allocated
&= ~(OPEN_REGION_PAGE_FLAG
);
922 if (page_table
[first_page
].bytes_used
== 0)
923 page_table
[first_page
].allocated
= FREE_PAGE_FLAG
;
926 /* Unallocate any unused pages. */
927 while (next_page
<= alloc_region
->last_page
) {
928 gc_assert(page_table
[next_page
].bytes_used
== 0);
929 page_table
[next_page
].allocated
= FREE_PAGE_FLAG
;
932 ret
= thread_mutex_unlock(&free_pages_lock
);
935 /* alloc_region is per-thread, we're ok to do this unlocked */
936 gc_set_region_empty(alloc_region
);
939 static inline void *gc_quick_alloc(long nbytes
);
941 /* Allocate a possibly large object. */
943 gc_alloc_large(long nbytes
, int unboxed
, struct alloc_region
*alloc_region
)
945 page_index_t first_page
;
946 page_index_t last_page
;
947 int orig_first_page_bytes_used
;
951 page_index_t next_page
;
954 ret
= thread_mutex_lock(&free_pages_lock
);
959 generations
[gc_alloc_generation
].alloc_large_unboxed_start_page
;
961 first_page
= generations
[gc_alloc_generation
].alloc_large_start_page
;
963 if (first_page
<= alloc_region
->last_page
) {
964 first_page
= alloc_region
->last_page
+1;
967 last_page
=gc_find_freeish_pages(&first_page
,nbytes
,unboxed
);
969 gc_assert(first_page
> alloc_region
->last_page
);
971 generations
[gc_alloc_generation
].alloc_large_unboxed_start_page
=
974 generations
[gc_alloc_generation
].alloc_large_start_page
= last_page
;
976 /* Set up the pages. */
977 orig_first_page_bytes_used
= page_table
[first_page
].bytes_used
;
979 /* If the first page was free then set up the gen, and
980 * first_object_offset. */
981 if (page_table
[first_page
].bytes_used
== 0) {
983 page_table
[first_page
].allocated
= UNBOXED_PAGE_FLAG
;
985 page_table
[first_page
].allocated
= BOXED_PAGE_FLAG
;
986 page_table
[first_page
].gen
= gc_alloc_generation
;
987 page_table
[first_page
].first_object_offset
= 0;
988 page_table
[first_page
].large_object
= 1;
992 gc_assert(page_table
[first_page
].allocated
== UNBOXED_PAGE_FLAG
);
994 gc_assert(page_table
[first_page
].allocated
== BOXED_PAGE_FLAG
);
995 gc_assert(page_table
[first_page
].gen
== gc_alloc_generation
);
996 gc_assert(page_table
[first_page
].large_object
== 1);
1000 /* Calc. the number of bytes used in this page. This is not
1001 * always the number of new bytes, unless it was free. */
1003 if ((bytes_used
= nbytes
+orig_first_page_bytes_used
) > PAGE_BYTES
) {
1004 bytes_used
= PAGE_BYTES
;
1007 page_table
[first_page
].bytes_used
= bytes_used
;
1008 byte_cnt
+= bytes_used
;
1010 next_page
= first_page
+1;
1012 /* All the rest of the pages should be free. We need to set their
1013 * first_object_offset pointer to the start of the region, and
1014 * set the bytes_used. */
1016 gc_assert(page_table
[next_page
].allocated
== FREE_PAGE_FLAG
);
1017 gc_assert(page_table
[next_page
].bytes_used
== 0);
1019 page_table
[next_page
].allocated
= UNBOXED_PAGE_FLAG
;
1021 page_table
[next_page
].allocated
= BOXED_PAGE_FLAG
;
1022 page_table
[next_page
].gen
= gc_alloc_generation
;
1023 page_table
[next_page
].large_object
= 1;
1025 page_table
[next_page
].first_object_offset
=
1026 orig_first_page_bytes_used
- PAGE_BYTES
*(next_page
-first_page
);
1028 /* Calculate the number of bytes used in this page. */
1030 if ((bytes_used
=(nbytes
+orig_first_page_bytes_used
)-byte_cnt
) > PAGE_BYTES
) {
1031 bytes_used
= PAGE_BYTES
;
1034 page_table
[next_page
].bytes_used
= bytes_used
;
1035 page_table
[next_page
].write_protected
=0;
1036 page_table
[next_page
].dont_move
=0;
1037 byte_cnt
+= bytes_used
;
1041 gc_assert((byte_cnt
-orig_first_page_bytes_used
) == nbytes
);
1043 bytes_allocated
+= nbytes
;
1044 generations
[gc_alloc_generation
].bytes_allocated
+= nbytes
;
1046 /* Add the region to the new_areas if requested. */
1048 add_new_area(first_page
,orig_first_page_bytes_used
,nbytes
);
1050 /* Bump up last_free_page */
1051 if (last_page
+1 > last_free_page
) {
1052 last_free_page
= last_page
+1;
1053 set_alloc_pointer((lispobj
)(((char *)heap_base
) + last_free_page
*PAGE_BYTES
));
1055 ret
= thread_mutex_unlock(&free_pages_lock
);
1056 gc_assert(ret
== 0);
1058 #ifdef READ_PROTECT_FREE_PAGES
1059 os_protect(page_address(first_page
),
1060 PAGE_BYTES
*(1+last_page
-first_page
),
1064 zero_dirty_pages(first_page
, last_page
);
1066 return page_address(first_page
);
1069 static page_index_t gencgc_alloc_start_page
= -1;
1072 gc_heap_exhausted_error_or_lose (long available
, long requested
)
1074 /* Write basic information before doing anything else: if we don't
1075 * call to lisp this is a must, and even if we do there is always
1076 * the danger that we bounce back here before the error has been
1077 * handled, or indeed even printed.
1079 fprintf(stderr
, "Heap exhausted during %s: %ld bytes available, %ld requested.\n",
1080 gc_active_p
? "garbage collection" : "allocation", available
, requested
);
1081 if (gc_active_p
|| (available
== 0)) {
1082 /* If we are in GC, or totally out of memory there is no way
1083 * to sanely transfer control to the lisp-side of things.
1085 struct thread
*thread
= arch_os_get_current_thread();
1086 print_generation_stats(1);
1087 fprintf(stderr
, "GC control variables:\n");
1088 fprintf(stderr
, " *GC-INHIBIT* = %s\n *GC-PENDING* = %s\n",
1089 SymbolValue(GC_INHIBIT
,thread
)==NIL
? "false" : "true",
1090 SymbolValue(GC_PENDING
,thread
)==NIL
? "false" : "true");
1091 #ifdef LISP_FEATURE_SB_THREAD
1092 fprintf(stderr
, " *STOP-FOR-GC-PENDING* = %s\n",
1093 SymbolValue(STOP_FOR_GC_PENDING
,thread
)==NIL
? "false" : "true");
1095 lose("Heap exhausted, game over.");
1098 /* FIXME: assert free_pages_lock held */
1099 (void)thread_mutex_unlock(&free_pages_lock
);
1100 funcall2(StaticSymbolFunction(HEAP_EXHAUSTED_ERROR
),
1101 alloc_number(available
), alloc_number(requested
));
1102 lose("HEAP-EXHAUSTED-ERROR fell through");
1107 gc_find_freeish_pages(page_index_t
*restart_page_ptr
, long nbytes
, int unboxed
)
1109 page_index_t first_page
;
1110 page_index_t last_page
;
1112 page_index_t restart_page
=*restart_page_ptr
;
1115 int large_p
=(nbytes
>=large_object_size
);
1116 /* FIXME: assert(free_pages_lock is held); */
1118 /* Search for a contiguous free space of at least nbytes. If it's
1119 * a large object then align it on a page boundary by searching
1120 * for a free page. */
1122 if (gencgc_alloc_start_page
!= -1) {
1123 restart_page
= gencgc_alloc_start_page
;
1127 first_page
= restart_page
;
1129 while ((first_page
< page_table_pages
)
1130 && (page_table
[first_page
].allocated
!= FREE_PAGE_FLAG
))
1133 while (first_page
< page_table_pages
) {
1134 if(page_table
[first_page
].allocated
== FREE_PAGE_FLAG
)
1136 if((page_table
[first_page
].allocated
==
1137 (unboxed
? UNBOXED_PAGE_FLAG
: BOXED_PAGE_FLAG
)) &&
1138 (page_table
[first_page
].large_object
== 0) &&
1139 (page_table
[first_page
].gen
== gc_alloc_generation
) &&
1140 (page_table
[first_page
].bytes_used
< (PAGE_BYTES
-32)) &&
1141 (page_table
[first_page
].write_protected
== 0) &&
1142 (page_table
[first_page
].dont_move
== 0)) {
1148 if (first_page
>= page_table_pages
)
1149 gc_heap_exhausted_error_or_lose(0, nbytes
);
1151 gc_assert(page_table
[first_page
].write_protected
== 0);
1153 last_page
= first_page
;
1154 bytes_found
= PAGE_BYTES
- page_table
[first_page
].bytes_used
;
1156 while (((bytes_found
< nbytes
)
1157 || (!large_p
&& (num_pages
< 2)))
1158 && (last_page
< (page_table_pages
-1))
1159 && (page_table
[last_page
+1].allocated
== FREE_PAGE_FLAG
)) {
1162 bytes_found
+= PAGE_BYTES
;
1163 gc_assert(page_table
[last_page
].write_protected
== 0);
1166 region_size
= (PAGE_BYTES
- page_table
[first_page
].bytes_used
)
1167 + PAGE_BYTES
*(last_page
-first_page
);
1169 gc_assert(bytes_found
== region_size
);
1170 restart_page
= last_page
+ 1;
1171 } while ((restart_page
< page_table_pages
) && (bytes_found
< nbytes
));
1173 /* Check for a failure */
1174 if ((restart_page
>= page_table_pages
) && (bytes_found
< nbytes
))
1175 gc_heap_exhausted_error_or_lose(bytes_found
, nbytes
);
1177 *restart_page_ptr
=first_page
;
1182 /* Allocate bytes. All the rest of the special-purpose allocation
1183 * functions will eventually call this */
1186 gc_alloc_with_region(long nbytes
,int unboxed_p
, struct alloc_region
*my_region
,
1189 void *new_free_pointer
;
1191 if(nbytes
>=large_object_size
)
1192 return gc_alloc_large(nbytes
,unboxed_p
,my_region
);
1194 /* Check whether there is room in the current alloc region. */
1195 new_free_pointer
= my_region
->free_pointer
+ nbytes
;
1197 /* fprintf(stderr, "alloc %d bytes from %p to %p\n", nbytes,
1198 my_region->free_pointer, new_free_pointer); */
1200 if (new_free_pointer
<= my_region
->end_addr
) {
1201 /* If so then allocate from the current alloc region. */
1202 void *new_obj
= my_region
->free_pointer
;
1203 my_region
->free_pointer
= new_free_pointer
;
1205 /* Unless a `quick' alloc was requested, check whether the
1206 alloc region is almost empty. */
1208 (my_region
->end_addr
- my_region
->free_pointer
) <= 32) {
1209 /* If so, finished with the current region. */
1210 gc_alloc_update_page_tables(unboxed_p
, my_region
);
1211 /* Set up a new region. */
1212 gc_alloc_new_region(32 /*bytes*/, unboxed_p
, my_region
);
1215 return((void *)new_obj
);
1218 /* Else not enough free space in the current region: retry with a
1221 gc_alloc_update_page_tables(unboxed_p
, my_region
);
1222 gc_alloc_new_region(nbytes
, unboxed_p
, my_region
);
1223 return gc_alloc_with_region(nbytes
,unboxed_p
,my_region
,0);
1226 /* these are only used during GC: all allocation from the mutator calls
1227 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1231 gc_general_alloc(long nbytes
,int unboxed_p
,int quick_p
)
1233 struct alloc_region
*my_region
=
1234 unboxed_p
? &unboxed_region
: &boxed_region
;
1235 return gc_alloc_with_region(nbytes
,unboxed_p
, my_region
,quick_p
);
1238 static inline void *
1239 gc_quick_alloc(long nbytes
)
1241 return gc_general_alloc(nbytes
,ALLOC_BOXED
,ALLOC_QUICK
);
1244 static inline void *
1245 gc_quick_alloc_large(long nbytes
)
1247 return gc_general_alloc(nbytes
,ALLOC_BOXED
,ALLOC_QUICK
);
1250 static inline void *
1251 gc_alloc_unboxed(long nbytes
)
1253 return gc_general_alloc(nbytes
,ALLOC_UNBOXED
,0);
1256 static inline void *
1257 gc_quick_alloc_unboxed(long nbytes
)
1259 return gc_general_alloc(nbytes
,ALLOC_UNBOXED
,ALLOC_QUICK
);
1262 static inline void *
1263 gc_quick_alloc_large_unboxed(long nbytes
)
1265 return gc_general_alloc(nbytes
,ALLOC_UNBOXED
,ALLOC_QUICK
);
1269 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1272 extern long (*scavtab
[256])(lispobj
*where
, lispobj object
);
1273 extern lispobj (*transother
[256])(lispobj object
);
1274 extern long (*sizetab
[256])(lispobj
*where
);
1276 /* Copy a large boxed object. If the object is in a large object
1277 * region then it is simply promoted, else it is copied. If it's large
1278 * enough then it's copied to a large object region.
1280 * Vectors may have shrunk. If the object is not copied the space
1281 * needs to be reclaimed, and the page_tables corrected. */
1283 copy_large_object(lispobj object
, long nwords
)
1287 page_index_t first_page
;
1289 gc_assert(is_lisp_pointer(object
));
1290 gc_assert(from_space_p(object
));
1291 gc_assert((nwords
& 0x01) == 0);
1294 /* Check whether it's in a large object region. */
1295 first_page
= find_page_index((void *)object
);
1296 gc_assert(first_page
>= 0);
1298 if (page_table
[first_page
].large_object
) {
1300 /* Promote the object. */
1302 long remaining_bytes
;
1303 page_index_t next_page
;
1305 long old_bytes_used
;
1307 /* Note: Any page write-protection must be removed, else a
1308 * later scavenge_newspace may incorrectly not scavenge these
1309 * pages. This would not be necessary if they are added to the
1310 * new areas, but let's do it for them all (they'll probably
1311 * be written anyway?). */
1313 gc_assert(page_table
[first_page
].first_object_offset
== 0);
1315 next_page
= first_page
;
1316 remaining_bytes
= nwords
*N_WORD_BYTES
;
1317 while (remaining_bytes
> PAGE_BYTES
) {
1318 gc_assert(page_table
[next_page
].gen
== from_space
);
1319 gc_assert(page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
);
1320 gc_assert(page_table
[next_page
].large_object
);
1321 gc_assert(page_table
[next_page
].first_object_offset
==
1322 -PAGE_BYTES
*(next_page
-first_page
));
1323 gc_assert(page_table
[next_page
].bytes_used
== PAGE_BYTES
);
1325 page_table
[next_page
].gen
= new_space
;
1327 /* Remove any write-protection. We should be able to rely
1328 * on the write-protect flag to avoid redundant calls. */
1329 if (page_table
[next_page
].write_protected
) {
1330 os_protect(page_address(next_page
), PAGE_BYTES
, OS_VM_PROT_ALL
);
1331 page_table
[next_page
].write_protected
= 0;
1333 remaining_bytes
-= PAGE_BYTES
;
1337 /* Now only one page remains, but the object may have shrunk
1338 * so there may be more unused pages which will be freed. */
1340 /* The object may have shrunk but shouldn't have grown. */
1341 gc_assert(page_table
[next_page
].bytes_used
>= remaining_bytes
);
1343 page_table
[next_page
].gen
= new_space
;
1344 gc_assert(page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
);
1346 /* Adjust the bytes_used. */
1347 old_bytes_used
= page_table
[next_page
].bytes_used
;
1348 page_table
[next_page
].bytes_used
= remaining_bytes
;
1350 bytes_freed
= old_bytes_used
- remaining_bytes
;
1352 /* Free any remaining pages; needs care. */
1354 while ((old_bytes_used
== PAGE_BYTES
) &&
1355 (page_table
[next_page
].gen
== from_space
) &&
1356 (page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
) &&
1357 page_table
[next_page
].large_object
&&
1358 (page_table
[next_page
].first_object_offset
==
1359 -(next_page
- first_page
)*PAGE_BYTES
)) {
1360 /* Checks out OK, free the page. Don't need to bother zeroing
1361 * pages as this should have been done before shrinking the
1362 * object. These pages shouldn't be write-protected as they
1363 * should be zero filled. */
1364 gc_assert(page_table
[next_page
].write_protected
== 0);
1366 old_bytes_used
= page_table
[next_page
].bytes_used
;
1367 page_table
[next_page
].allocated
= FREE_PAGE_FLAG
;
1368 page_table
[next_page
].bytes_used
= 0;
1369 bytes_freed
+= old_bytes_used
;
1373 generations
[from_space
].bytes_allocated
-= N_WORD_BYTES
*nwords
+
1375 generations
[new_space
].bytes_allocated
+= N_WORD_BYTES
*nwords
;
1376 bytes_allocated
-= bytes_freed
;
1378 /* Add the region to the new_areas if requested. */
1379 add_new_area(first_page
,0,nwords
*N_WORD_BYTES
);
1383 /* Get tag of object. */
1384 tag
= lowtag_of(object
);
1386 /* Allocate space. */
1387 new = gc_quick_alloc_large(nwords
*N_WORD_BYTES
);
1389 memcpy(new,native_pointer(object
),nwords
*N_WORD_BYTES
);
1391 /* Return Lisp pointer of new object. */
1392 return ((lispobj
) new) | tag
;
1396 /* to copy unboxed objects */
1398 copy_unboxed_object(lispobj object
, long nwords
)
1403 gc_assert(is_lisp_pointer(object
));
1404 gc_assert(from_space_p(object
));
1405 gc_assert((nwords
& 0x01) == 0);
1407 /* Get tag of object. */
1408 tag
= lowtag_of(object
);
1410 /* Allocate space. */
1411 new = gc_quick_alloc_unboxed(nwords
*N_WORD_BYTES
);
1413 memcpy(new,native_pointer(object
),nwords
*N_WORD_BYTES
);
1415 /* Return Lisp pointer of new object. */
1416 return ((lispobj
) new) | tag
;
1419 /* to copy large unboxed objects
1421 * If the object is in a large object region then it is simply
1422 * promoted, else it is copied. If it's large enough then it's copied
1423 * to a large object region.
1425 * Bignums and vectors may have shrunk. If the object is not copied
1426 * the space needs to be reclaimed, and the page_tables corrected.
1428 * KLUDGE: There's a lot of cut-and-paste duplication between this
1429 * function and copy_large_object(..). -- WHN 20000619 */
1431 copy_large_unboxed_object(lispobj object
, long nwords
)
1435 page_index_t first_page
;
1437 gc_assert(is_lisp_pointer(object
));
1438 gc_assert(from_space_p(object
));
1439 gc_assert((nwords
& 0x01) == 0);
1441 if ((nwords
> 1024*1024) && gencgc_verbose
)
1442 FSHOW((stderr
, "/copy_large_unboxed_object: %d bytes\n", nwords
*N_WORD_BYTES
));
1444 /* Check whether it's a large object. */
1445 first_page
= find_page_index((void *)object
);
1446 gc_assert(first_page
>= 0);
1448 if (page_table
[first_page
].large_object
) {
1449 /* Promote the object. Note: Unboxed objects may have been
1450 * allocated to a BOXED region so it may be necessary to
1451 * change the region to UNBOXED. */
1452 long remaining_bytes
;
1453 page_index_t next_page
;
1455 long old_bytes_used
;
1457 gc_assert(page_table
[first_page
].first_object_offset
== 0);
1459 next_page
= first_page
;
1460 remaining_bytes
= nwords
*N_WORD_BYTES
;
1461 while (remaining_bytes
> PAGE_BYTES
) {
1462 gc_assert(page_table
[next_page
].gen
== from_space
);
1463 gc_assert((page_table
[next_page
].allocated
== UNBOXED_PAGE_FLAG
)
1464 || (page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
));
1465 gc_assert(page_table
[next_page
].large_object
);
1466 gc_assert(page_table
[next_page
].first_object_offset
==
1467 -PAGE_BYTES
*(next_page
-first_page
));
1468 gc_assert(page_table
[next_page
].bytes_used
== PAGE_BYTES
);
1470 page_table
[next_page
].gen
= new_space
;
1471 page_table
[next_page
].allocated
= UNBOXED_PAGE_FLAG
;
1472 remaining_bytes
-= PAGE_BYTES
;
1476 /* Now only one page remains, but the object may have shrunk so
1477 * there may be more unused pages which will be freed. */
1479 /* Object may have shrunk but shouldn't have grown - check. */
1480 gc_assert(page_table
[next_page
].bytes_used
>= remaining_bytes
);
1482 page_table
[next_page
].gen
= new_space
;
1483 page_table
[next_page
].allocated
= UNBOXED_PAGE_FLAG
;
1485 /* Adjust the bytes_used. */
1486 old_bytes_used
= page_table
[next_page
].bytes_used
;
1487 page_table
[next_page
].bytes_used
= remaining_bytes
;
1489 bytes_freed
= old_bytes_used
- remaining_bytes
;
1491 /* Free any remaining pages; needs care. */
1493 while ((old_bytes_used
== PAGE_BYTES
) &&
1494 (page_table
[next_page
].gen
== from_space
) &&
1495 ((page_table
[next_page
].allocated
== UNBOXED_PAGE_FLAG
)
1496 || (page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
)) &&
1497 page_table
[next_page
].large_object
&&
1498 (page_table
[next_page
].first_object_offset
==
1499 -(next_page
- first_page
)*PAGE_BYTES
)) {
1500 /* Checks out OK, free the page. Don't need to both zeroing
1501 * pages as this should have been done before shrinking the
1502 * object. These pages shouldn't be write-protected, even if
1503 * boxed they should be zero filled. */
1504 gc_assert(page_table
[next_page
].write_protected
== 0);
1506 old_bytes_used
= page_table
[next_page
].bytes_used
;
1507 page_table
[next_page
].allocated
= FREE_PAGE_FLAG
;
1508 page_table
[next_page
].bytes_used
= 0;
1509 bytes_freed
+= old_bytes_used
;
1513 if ((bytes_freed
> 0) && gencgc_verbose
)
1515 "/copy_large_unboxed bytes_freed=%d\n",
1518 generations
[from_space
].bytes_allocated
-= nwords
*N_WORD_BYTES
+ bytes_freed
;
1519 generations
[new_space
].bytes_allocated
+= nwords
*N_WORD_BYTES
;
1520 bytes_allocated
-= bytes_freed
;
1525 /* Get tag of object. */
1526 tag
= lowtag_of(object
);
1528 /* Allocate space. */
1529 new = gc_quick_alloc_large_unboxed(nwords
*N_WORD_BYTES
);
1531 /* Copy the object. */
1532 memcpy(new,native_pointer(object
),nwords
*N_WORD_BYTES
);
1534 /* Return Lisp pointer of new object. */
1535 return ((lispobj
) new) | tag
;
1544 * code and code-related objects
1547 static lispobj trans_fun_header(lispobj object);
1548 static lispobj trans_boxed(lispobj object);
1551 /* Scan a x86 compiled code object, looking for possible fixups that
1552 * have been missed after a move.
1554 * Two types of fixups are needed:
1555 * 1. Absolute fixups to within the code object.
1556 * 2. Relative fixups to outside the code object.
1558 * Currently only absolute fixups to the constant vector, or to the
1559 * code area are checked. */
1561 sniff_code_object(struct code
*code
, unsigned long displacement
)
1563 #ifdef LISP_FEATURE_X86
1564 long nheader_words
, ncode_words
, nwords
;
1566 void *constants_start_addr
= NULL
, *constants_end_addr
;
1567 void *code_start_addr
, *code_end_addr
;
1568 int fixup_found
= 0;
1570 if (!check_code_fixups
)
1573 ncode_words
= fixnum_value(code
->code_size
);
1574 nheader_words
= HeaderValue(*(lispobj
*)code
);
1575 nwords
= ncode_words
+ nheader_words
;
1577 constants_start_addr
= (void *)code
+ 5*N_WORD_BYTES
;
1578 constants_end_addr
= (void *)code
+ nheader_words
*N_WORD_BYTES
;
1579 code_start_addr
= (void *)code
+ nheader_words
*N_WORD_BYTES
;
1580 code_end_addr
= (void *)code
+ nwords
*N_WORD_BYTES
;
1582 /* Work through the unboxed code. */
1583 for (p
= code_start_addr
; p
< code_end_addr
; p
++) {
1584 void *data
= *(void **)p
;
1585 unsigned d1
= *((unsigned char *)p
- 1);
1586 unsigned d2
= *((unsigned char *)p
- 2);
1587 unsigned d3
= *((unsigned char *)p
- 3);
1588 unsigned d4
= *((unsigned char *)p
- 4);
1590 unsigned d5
= *((unsigned char *)p
- 5);
1591 unsigned d6
= *((unsigned char *)p
- 6);
1594 /* Check for code references. */
1595 /* Check for a 32 bit word that looks like an absolute
1596 reference to within the code adea of the code object. */
1597 if ((data
>= (code_start_addr
-displacement
))
1598 && (data
< (code_end_addr
-displacement
))) {
1599 /* function header */
1601 && (((unsigned)p
- 4 - 4*HeaderValue(*((unsigned *)p
-1))) == (unsigned)code
)) {
1602 /* Skip the function header */
1606 /* the case of PUSH imm32 */
1610 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1611 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1612 FSHOW((stderr
, "/PUSH $0x%.8x\n", data
));
1614 /* the case of MOV [reg-8],imm32 */
1616 && (d2
==0x40 || d2
==0x41 || d2
==0x42 || d2
==0x43
1617 || d2
==0x45 || d2
==0x46 || d2
==0x47)
1621 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1622 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1623 FSHOW((stderr
, "/MOV [reg-8],$0x%.8x\n", data
));
1625 /* the case of LEA reg,[disp32] */
1626 if ((d2
== 0x8d) && ((d1
& 0xc7) == 5)) {
1629 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1630 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1631 FSHOW((stderr
,"/LEA reg,[$0x%.8x]\n", data
));
1635 /* Check for constant references. */
1636 /* Check for a 32 bit word that looks like an absolute
1637 reference to within the constant vector. Constant references
1639 if ((data
>= (constants_start_addr
-displacement
))
1640 && (data
< (constants_end_addr
-displacement
))
1641 && (((unsigned)data
& 0x3) == 0)) {
1646 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1647 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1648 FSHOW((stderr
,"/MOV eax,0x%.8x\n", data
));
1651 /* the case of MOV m32,EAX */
1655 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1656 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1657 FSHOW((stderr
, "/MOV 0x%.8x,eax\n", data
));
1660 /* the case of CMP m32,imm32 */
1661 if ((d1
== 0x3d) && (d2
== 0x81)) {
1664 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1665 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1667 FSHOW((stderr
, "/CMP 0x%.8x,immed32\n", data
));
1670 /* Check for a mod=00, r/m=101 byte. */
1671 if ((d1
& 0xc7) == 5) {
1676 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1677 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1678 FSHOW((stderr
,"/CMP 0x%.8x,reg\n", data
));
1680 /* the case of CMP reg32,m32 */
1684 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1685 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1686 FSHOW((stderr
, "/CMP reg32,0x%.8x\n", data
));
1688 /* the case of MOV m32,reg32 */
1692 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1693 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1694 FSHOW((stderr
, "/MOV 0x%.8x,reg32\n", data
));
1696 /* the case of MOV reg32,m32 */
1700 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1701 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1702 FSHOW((stderr
, "/MOV reg32,0x%.8x\n", data
));
1704 /* the case of LEA reg32,m32 */
1708 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1709 p
, d6
, d5
, d4
, d3
, d2
, d1
, data
));
1710 FSHOW((stderr
, "/LEA reg32,0x%.8x\n", data
));
1716 /* If anything was found, print some information on the code
1720 "/compiled code object at %x: header words = %d, code words = %d\n",
1721 code
, nheader_words
, ncode_words
));
1723 "/const start = %x, end = %x\n",
1724 constants_start_addr
, constants_end_addr
));
1726 "/code start = %x, end = %x\n",
1727 code_start_addr
, code_end_addr
));
1733 gencgc_apply_code_fixups(struct code
*old_code
, struct code
*new_code
)
1735 /* x86-64 uses pc-relative addressing instead of this kludge */
1736 #ifndef LISP_FEATURE_X86_64
1737 long nheader_words
, ncode_words
, nwords
;
1738 void *constants_start_addr
, *constants_end_addr
;
1739 void *code_start_addr
, *code_end_addr
;
1740 lispobj fixups
= NIL
;
1741 unsigned long displacement
= (unsigned long)new_code
- (unsigned long)old_code
;
1742 struct vector
*fixups_vector
;
1744 ncode_words
= fixnum_value(new_code
->code_size
);
1745 nheader_words
= HeaderValue(*(lispobj
*)new_code
);
1746 nwords
= ncode_words
+ nheader_words
;
1748 "/compiled code object at %x: header words = %d, code words = %d\n",
1749 new_code, nheader_words, ncode_words)); */
1750 constants_start_addr
= (void *)new_code
+ 5*N_WORD_BYTES
;
1751 constants_end_addr
= (void *)new_code
+ nheader_words
*N_WORD_BYTES
;
1752 code_start_addr
= (void *)new_code
+ nheader_words
*N_WORD_BYTES
;
1753 code_end_addr
= (void *)new_code
+ nwords
*N_WORD_BYTES
;
1756 "/const start = %x, end = %x\n",
1757 constants_start_addr,constants_end_addr));
1759 "/code start = %x; end = %x\n",
1760 code_start_addr,code_end_addr));
1763 /* The first constant should be a pointer to the fixups for this
1764 code objects. Check. */
1765 fixups
= new_code
->constants
[0];
1767 /* It will be 0 or the unbound-marker if there are no fixups (as
1768 * will be the case if the code object has been purified, for
1769 * example) and will be an other pointer if it is valid. */
1770 if ((fixups
== 0) || (fixups
== UNBOUND_MARKER_WIDETAG
) ||
1771 !is_lisp_pointer(fixups
)) {
1772 /* Check for possible errors. */
1773 if (check_code_fixups
)
1774 sniff_code_object(new_code
, displacement
);
1779 fixups_vector
= (struct vector
*)native_pointer(fixups
);
1781 /* Could be pointing to a forwarding pointer. */
1782 /* FIXME is this always in from_space? if so, could replace this code with
1783 * forwarding_pointer_p/forwarding_pointer_value */
1784 if (is_lisp_pointer(fixups
) &&
1785 (find_page_index((void*)fixups_vector
) != -1) &&
1786 (fixups_vector
->header
== 0x01)) {
1787 /* If so, then follow it. */
1788 /*SHOW("following pointer to a forwarding pointer");*/
1789 fixups_vector
= (struct vector
*)native_pointer((lispobj
)fixups_vector
->length
);
1792 /*SHOW("got fixups");*/
1794 if (widetag_of(fixups_vector
->header
) == SIMPLE_ARRAY_WORD_WIDETAG
) {
1795 /* Got the fixups for the code block. Now work through the vector,
1796 and apply a fixup at each address. */
1797 long length
= fixnum_value(fixups_vector
->length
);
1799 for (i
= 0; i
< length
; i
++) {
1800 unsigned long offset
= fixups_vector
->data
[i
];
1801 /* Now check the current value of offset. */
1802 unsigned long old_value
=
1803 *(unsigned long *)((unsigned long)code_start_addr
+ offset
);
1805 /* If it's within the old_code object then it must be an
1806 * absolute fixup (relative ones are not saved) */
1807 if ((old_value
>= (unsigned long)old_code
)
1808 && (old_value
< ((unsigned long)old_code
+ nwords
*N_WORD_BYTES
)))
1809 /* So add the dispacement. */
1810 *(unsigned long *)((unsigned long)code_start_addr
+ offset
) =
1811 old_value
+ displacement
;
1813 /* It is outside the old code object so it must be a
1814 * relative fixup (absolute fixups are not saved). So
1815 * subtract the displacement. */
1816 *(unsigned long *)((unsigned long)code_start_addr
+ offset
) =
1817 old_value
- displacement
;
1820 /* This used to just print a note to stderr, but a bogus fixup seems to
1821 * indicate real heap corruption, so a hard hailure is in order. */
1822 lose("fixup vector %p has a bad widetag: %d\n", fixups_vector
, widetag_of(fixups_vector
->header
));
1825 /* Check for possible errors. */
1826 if (check_code_fixups
) {
1827 sniff_code_object(new_code
,displacement
);
1834 trans_boxed_large(lispobj object
)
1837 unsigned long length
;
1839 gc_assert(is_lisp_pointer(object
));
1841 header
= *((lispobj
*) native_pointer(object
));
1842 length
= HeaderValue(header
) + 1;
1843 length
= CEILING(length
, 2);
1845 return copy_large_object(object
, length
);
1848 /* Doesn't seem to be used, delete it after the grace period. */
1851 trans_unboxed_large(lispobj object
)
1854 unsigned long length
;
1856 gc_assert(is_lisp_pointer(object
));
1858 header
= *((lispobj
*) native_pointer(object
));
1859 length
= HeaderValue(header
) + 1;
1860 length
= CEILING(length
, 2);
1862 return copy_large_unboxed_object(object
, length
);
1868 * Lutexes. Using the normal finalization machinery for finalizing
1869 * lutexes is tricky, since the finalization depends on working lutexes.
1870 * So we track the lutexes in the GC and finalize them manually.
1873 #if defined(LUTEX_WIDETAG)
1876 * Start tracking LUTEX in the GC, by adding it to the linked list of
1877 * lutexes in the nursery generation. The caller is responsible for
1878 * locking, and GCs must be inhibited until the registration is
1882 gencgc_register_lutex (struct lutex
*lutex
) {
1883 int index
= find_page_index(lutex
);
1884 generation_index_t gen
;
1887 /* This lutex is in static space, so we don't need to worry about
1893 gen
= page_table
[index
].gen
;
1895 gc_assert(gen
>= 0);
1896 gc_assert(gen
< NUM_GENERATIONS
);
1898 head
= generations
[gen
].lutexes
;
1905 generations
[gen
].lutexes
= lutex
;
1909 * Stop tracking LUTEX in the GC by removing it from the appropriate
1910 * linked lists. This will only be called during GC, so no locking is
1914 gencgc_unregister_lutex (struct lutex
*lutex
) {
1916 lutex
->prev
->next
= lutex
->next
;
1918 generations
[lutex
->gen
].lutexes
= lutex
->next
;
1922 lutex
->next
->prev
= lutex
->prev
;
1931 * Mark all lutexes in generation GEN as not live.
1934 unmark_lutexes (generation_index_t gen
) {
1935 struct lutex
*lutex
= generations
[gen
].lutexes
;
1939 lutex
= lutex
->next
;
1944 * Finalize all lutexes in generation GEN that have not been marked live.
1947 reap_lutexes (generation_index_t gen
) {
1948 struct lutex
*lutex
= generations
[gen
].lutexes
;
1951 struct lutex
*next
= lutex
->next
;
1953 lutex_destroy((tagged_lutex_t
) lutex
);
1954 gencgc_unregister_lutex(lutex
);
1961 * Mark LUTEX as live.
1964 mark_lutex (lispobj tagged_lutex
) {
1965 struct lutex
*lutex
= (struct lutex
*) native_pointer(tagged_lutex
);
1971 * Move all lutexes in generation FROM to generation TO.
1974 move_lutexes (generation_index_t from
, generation_index_t to
) {
1975 struct lutex
*tail
= generations
[from
].lutexes
;
1977 /* Nothing to move */
1981 /* Change the generation of the lutexes in FROM. */
1982 while (tail
->next
) {
1988 /* Link the last lutex in the FROM list to the start of the TO list */
1989 tail
->next
= generations
[to
].lutexes
;
1991 /* And vice versa */
1992 if (generations
[to
].lutexes
) {
1993 generations
[to
].lutexes
->prev
= tail
;
1996 /* And update the generations structures to match this */
1997 generations
[to
].lutexes
= generations
[from
].lutexes
;
1998 generations
[from
].lutexes
= NULL
;
2002 scav_lutex(lispobj
*where
, lispobj object
)
2004 mark_lutex((lispobj
) where
);
2006 return CEILING(sizeof(struct lutex
)/sizeof(lispobj
), 2);
2010 trans_lutex(lispobj object
)
2012 struct lutex
*lutex
= (struct lutex
*) native_pointer(object
);
2014 size_t words
= CEILING(sizeof(struct lutex
)/sizeof(lispobj
), 2);
2015 gc_assert(is_lisp_pointer(object
));
2016 copied
= copy_object(object
, words
);
2018 /* Update the links, since the lutex moved in memory. */
2020 lutex
->next
->prev
= (struct lutex
*) native_pointer(copied
);
2024 lutex
->prev
->next
= (struct lutex
*) native_pointer(copied
);
2026 generations
[lutex
->gen
].lutexes
=
2027 (struct lutex
*) native_pointer(copied
);
2034 size_lutex(lispobj
*where
)
2036 return CEILING(sizeof(struct lutex
)/sizeof(lispobj
), 2);
2038 #endif /* LUTEX_WIDETAG */
2045 /* XX This is a hack adapted from cgc.c. These don't work too
2046 * efficiently with the gencgc as a list of the weak pointers is
2047 * maintained within the objects which causes writes to the pages. A
2048 * limited attempt is made to avoid unnecessary writes, but this needs
2050 #define WEAK_POINTER_NWORDS \
2051 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
2054 scav_weak_pointer(lispobj
*where
, lispobj object
)
2056 /* Since we overwrite the 'next' field, we have to make
2057 * sure not to do so for pointers already in the list.
2058 * Instead of searching the list of weak_pointers each
2059 * time, we ensure that next is always NULL when the weak
2060 * pointer isn't in the list, and not NULL otherwise.
2061 * Since we can't use NULL to denote end of list, we
2062 * use a pointer back to the same weak_pointer.
2064 struct weak_pointer
* wp
= (struct weak_pointer
*)where
;
2066 if (NULL
== wp
->next
) {
2067 wp
->next
= weak_pointers
;
2069 if (NULL
== wp
->next
)
2073 /* Do not let GC scavenge the value slot of the weak pointer.
2074 * (That is why it is a weak pointer.) */
2076 return WEAK_POINTER_NWORDS
;
2081 search_read_only_space(void *pointer
)
2083 lispobj
*start
= (lispobj
*) READ_ONLY_SPACE_START
;
2084 lispobj
*end
= (lispobj
*) SymbolValue(READ_ONLY_SPACE_FREE_POINTER
,0);
2085 if ((pointer
< (void *)start
) || (pointer
>= (void *)end
))
2087 return (gc_search_space(start
,
2088 (((lispobj
*)pointer
)+2)-start
,
2089 (lispobj
*) pointer
));
2093 search_static_space(void *pointer
)
2095 lispobj
*start
= (lispobj
*)STATIC_SPACE_START
;
2096 lispobj
*end
= (lispobj
*)SymbolValue(STATIC_SPACE_FREE_POINTER
,0);
2097 if ((pointer
< (void *)start
) || (pointer
>= (void *)end
))
2099 return (gc_search_space(start
,
2100 (((lispobj
*)pointer
)+2)-start
,
2101 (lispobj
*) pointer
));
2104 /* a faster version for searching the dynamic space. This will work even
2105 * if the object is in a current allocation region. */
2107 search_dynamic_space(void *pointer
)
2109 page_index_t page_index
= find_page_index(pointer
);
2112 /* The address may be invalid, so do some checks. */
2113 if ((page_index
== -1) ||
2114 (page_table
[page_index
].allocated
== FREE_PAGE_FLAG
))
2116 start
= (lispobj
*)((void *)page_address(page_index
)
2117 + page_table
[page_index
].first_object_offset
);
2118 return (gc_search_space(start
,
2119 (((lispobj
*)pointer
)+2)-start
,
2120 (lispobj
*)pointer
));
2123 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2125 /* Helper for valid_lisp_pointer_p and
2126 * possibly_valid_dynamic_space_pointer.
2128 * pointer is the pointer to validate, and start_addr is the address
2129 * of the enclosing object.
2132 looks_like_valid_lisp_pointer_p(lispobj
*pointer
, lispobj
*start_addr
)
2134 /* We need to allow raw pointers into Code objects for return
2135 * addresses. This will also pick up pointers to functions in code
2137 if (widetag_of(*start_addr
) == CODE_HEADER_WIDETAG
)
2138 /* XXX could do some further checks here */
2141 if (!is_lisp_pointer((lispobj
)pointer
)) {
2145 /* Check that the object pointed to is consistent with the pointer
2147 switch (lowtag_of((lispobj
)pointer
)) {
2148 case FUN_POINTER_LOWTAG
:
2149 /* Start_addr should be the enclosing code object, or a closure
2151 switch (widetag_of(*start_addr
)) {
2152 case CODE_HEADER_WIDETAG
:
2153 /* This case is probably caught above. */
2155 case CLOSURE_HEADER_WIDETAG
:
2156 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG
:
2157 if ((unsigned long)pointer
!=
2158 ((unsigned long)start_addr
+FUN_POINTER_LOWTAG
)) {
2162 pointer
, start_addr
, *start_addr
));
2170 pointer
, start_addr
, *start_addr
));
2174 case LIST_POINTER_LOWTAG
:
2175 if ((unsigned long)pointer
!=
2176 ((unsigned long)start_addr
+LIST_POINTER_LOWTAG
)) {
2180 pointer
, start_addr
, *start_addr
));
2183 /* Is it plausible cons? */
2184 if ((is_lisp_pointer(start_addr
[0])
2185 || (fixnump(start_addr
[0]))
2186 || (widetag_of(start_addr
[0]) == CHARACTER_WIDETAG
)
2187 #if N_WORD_BITS == 64
2188 || (widetag_of(start_addr
[0]) == SINGLE_FLOAT_WIDETAG
)
2190 || (widetag_of(start_addr
[0]) == UNBOUND_MARKER_WIDETAG
))
2191 && (is_lisp_pointer(start_addr
[1])
2192 || (fixnump(start_addr
[1]))
2193 || (widetag_of(start_addr
[1]) == CHARACTER_WIDETAG
)
2194 #if N_WORD_BITS == 64
2195 || (widetag_of(start_addr
[1]) == SINGLE_FLOAT_WIDETAG
)
2197 || (widetag_of(start_addr
[1]) == UNBOUND_MARKER_WIDETAG
)))
2203 pointer
, start_addr
, *start_addr
));
2206 case INSTANCE_POINTER_LOWTAG
:
2207 if ((unsigned long)pointer
!=
2208 ((unsigned long)start_addr
+INSTANCE_POINTER_LOWTAG
)) {
2212 pointer
, start_addr
, *start_addr
));
2215 if (widetag_of(start_addr
[0]) != INSTANCE_HEADER_WIDETAG
) {
2219 pointer
, start_addr
, *start_addr
));
2223 case OTHER_POINTER_LOWTAG
:
2224 if ((unsigned long)pointer
!=
2225 ((unsigned long)start_addr
+OTHER_POINTER_LOWTAG
)) {
2229 pointer
, start_addr
, *start_addr
));
2232 /* Is it plausible? Not a cons. XXX should check the headers. */
2233 if (is_lisp_pointer(start_addr
[0]) || ((start_addr
[0] & 3) == 0)) {
2237 pointer
, start_addr
, *start_addr
));
2240 switch (widetag_of(start_addr
[0])) {
2241 case UNBOUND_MARKER_WIDETAG
:
2242 case NO_TLS_VALUE_MARKER_WIDETAG
:
2243 case CHARACTER_WIDETAG
:
2244 #if N_WORD_BITS == 64
2245 case SINGLE_FLOAT_WIDETAG
:
2250 pointer
, start_addr
, *start_addr
));
2253 /* only pointed to by function pointers? */
2254 case CLOSURE_HEADER_WIDETAG
:
2255 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG
:
2259 pointer
, start_addr
, *start_addr
));
2262 case INSTANCE_HEADER_WIDETAG
:
2266 pointer
, start_addr
, *start_addr
));
2269 /* the valid other immediate pointer objects */
2270 case SIMPLE_VECTOR_WIDETAG
:
2272 case COMPLEX_WIDETAG
:
2273 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2274 case COMPLEX_SINGLE_FLOAT_WIDETAG
:
2276 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2277 case COMPLEX_DOUBLE_FLOAT_WIDETAG
:
2279 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2280 case COMPLEX_LONG_FLOAT_WIDETAG
:
2282 case SIMPLE_ARRAY_WIDETAG
:
2283 case COMPLEX_BASE_STRING_WIDETAG
:
2284 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
2285 case COMPLEX_CHARACTER_STRING_WIDETAG
:
2287 case COMPLEX_VECTOR_NIL_WIDETAG
:
2288 case COMPLEX_BIT_VECTOR_WIDETAG
:
2289 case COMPLEX_VECTOR_WIDETAG
:
2290 case COMPLEX_ARRAY_WIDETAG
:
2291 case VALUE_CELL_HEADER_WIDETAG
:
2292 case SYMBOL_HEADER_WIDETAG
:
2294 case CODE_HEADER_WIDETAG
:
2295 case BIGNUM_WIDETAG
:
2296 #if N_WORD_BITS != 64
2297 case SINGLE_FLOAT_WIDETAG
:
2299 case DOUBLE_FLOAT_WIDETAG
:
2300 #ifdef LONG_FLOAT_WIDETAG
2301 case LONG_FLOAT_WIDETAG
:
2303 case SIMPLE_BASE_STRING_WIDETAG
:
2304 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2305 case SIMPLE_CHARACTER_STRING_WIDETAG
:
2307 case SIMPLE_BIT_VECTOR_WIDETAG
:
2308 case SIMPLE_ARRAY_NIL_WIDETAG
:
2309 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG
:
2310 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG
:
2311 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG
:
2312 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG
:
2313 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG
:
2314 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG
:
2315 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2316 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
:
2318 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG
:
2319 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
:
2320 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2321 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
:
2323 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2324 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
:
2326 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2327 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
:
2329 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2330 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
:
2332 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2333 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
:
2335 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2336 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
:
2338 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2339 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
:
2341 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2342 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
:
2344 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2345 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
:
2347 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG
:
2348 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG
:
2349 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2350 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
:
2352 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2353 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
:
2355 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2356 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
:
2358 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2359 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
:
2362 case WEAK_POINTER_WIDETAG
:
2363 #ifdef LUTEX_WIDETAG
2372 pointer
, start_addr
, *start_addr
));
2380 pointer
, start_addr
, *start_addr
));
2388 /* Used by the debugger to validate possibly bogus pointers before
2389 * calling MAKE-LISP-OBJ on them.
2391 * FIXME: We would like to make this perfect, because if the debugger
2392 * constructs a reference to a bugs lisp object, and it ends up in a
2393 * location scavenged by the GC all hell breaks loose.
2395 * Whereas possibly_valid_dynamic_space_pointer has to be conservative
2396 * and return true for all valid pointers, this could actually be eager
2397 * and lie about a few pointers without bad results... but that should
2398 * be reflected in the name.
2401 valid_lisp_pointer_p(lispobj
*pointer
)
2404 if (((start
=search_dynamic_space(pointer
))!=NULL
) ||
2405 ((start
=search_static_space(pointer
))!=NULL
) ||
2406 ((start
=search_read_only_space(pointer
))!=NULL
))
2407 return looks_like_valid_lisp_pointer_p(pointer
, start
);
2412 /* Is there any possibility that pointer is a valid Lisp object
2413 * reference, and/or something else (e.g. subroutine call return
2414 * address) which should prevent us from moving the referred-to thing?
2415 * This is called from preserve_pointers() */
2417 possibly_valid_dynamic_space_pointer(lispobj
*pointer
)
2419 lispobj
*start_addr
;
2421 /* Find the object start address. */
2422 if ((start_addr
= search_dynamic_space(pointer
)) == NULL
) {
2426 return looks_like_valid_lisp_pointer_p(pointer
, start_addr
);
2429 /* Adjust large bignum and vector objects. This will adjust the
2430 * allocated region if the size has shrunk, and move unboxed objects
2431 * into unboxed pages. The pages are not promoted here, and the
2432 * promoted region is not added to the new_regions; this is really
2433 * only designed to be called from preserve_pointer(). Shouldn't fail
2434 * if this is missed, just may delay the moving of objects to unboxed
2435 * pages, and the freeing of pages. */
2437 maybe_adjust_large_object(lispobj
*where
)
2439 page_index_t first_page
;
2440 page_index_t next_page
;
2443 long remaining_bytes
;
2445 long old_bytes_used
;
2449 /* Check whether it's a vector or bignum object. */
2450 switch (widetag_of(where
[0])) {
2451 case SIMPLE_VECTOR_WIDETAG
:
2452 boxed
= BOXED_PAGE_FLAG
;
2454 case BIGNUM_WIDETAG
:
2455 case SIMPLE_BASE_STRING_WIDETAG
:
2456 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2457 case SIMPLE_CHARACTER_STRING_WIDETAG
:
2459 case SIMPLE_BIT_VECTOR_WIDETAG
:
2460 case SIMPLE_ARRAY_NIL_WIDETAG
:
2461 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG
:
2462 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG
:
2463 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG
:
2464 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG
:
2465 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG
:
2466 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG
:
2467 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2468 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
:
2470 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG
:
2471 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
:
2472 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2473 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
:
2475 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2476 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
:
2478 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2479 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
:
2481 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2482 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
:
2484 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2485 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
:
2487 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2488 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
:
2490 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2491 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
:
2493 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2494 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
:
2496 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2497 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
:
2499 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG
:
2500 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG
:
2501 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2502 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
:
2504 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2505 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
:
2507 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2508 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
:
2510 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2511 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
:
2513 boxed
= UNBOXED_PAGE_FLAG
;
2519 /* Find its current size. */
2520 nwords
= (sizetab
[widetag_of(where
[0])])(where
);
2522 first_page
= find_page_index((void *)where
);
2523 gc_assert(first_page
>= 0);
2525 /* Note: Any page write-protection must be removed, else a later
2526 * scavenge_newspace may incorrectly not scavenge these pages.
2527 * This would not be necessary if they are added to the new areas,
2528 * but lets do it for them all (they'll probably be written
2531 gc_assert(page_table
[first_page
].first_object_offset
== 0);
2533 next_page
= first_page
;
2534 remaining_bytes
= nwords
*N_WORD_BYTES
;
2535 while (remaining_bytes
> PAGE_BYTES
) {
2536 gc_assert(page_table
[next_page
].gen
== from_space
);
2537 gc_assert((page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
)
2538 || (page_table
[next_page
].allocated
== UNBOXED_PAGE_FLAG
));
2539 gc_assert(page_table
[next_page
].large_object
);
2540 gc_assert(page_table
[next_page
].first_object_offset
==
2541 -PAGE_BYTES
*(next_page
-first_page
));
2542 gc_assert(page_table
[next_page
].bytes_used
== PAGE_BYTES
);
2544 page_table
[next_page
].allocated
= boxed
;
2546 /* Shouldn't be write-protected at this stage. Essential that the
2548 gc_assert(!page_table
[next_page
].write_protected
);
2549 remaining_bytes
-= PAGE_BYTES
;
2553 /* Now only one page remains, but the object may have shrunk so
2554 * there may be more unused pages which will be freed. */
2556 /* Object may have shrunk but shouldn't have grown - check. */
2557 gc_assert(page_table
[next_page
].bytes_used
>= remaining_bytes
);
2559 page_table
[next_page
].allocated
= boxed
;
2560 gc_assert(page_table
[next_page
].allocated
==
2561 page_table
[first_page
].allocated
);
2563 /* Adjust the bytes_used. */
2564 old_bytes_used
= page_table
[next_page
].bytes_used
;
2565 page_table
[next_page
].bytes_used
= remaining_bytes
;
2567 bytes_freed
= old_bytes_used
- remaining_bytes
;
2569 /* Free any remaining pages; needs care. */
2571 while ((old_bytes_used
== PAGE_BYTES
) &&
2572 (page_table
[next_page
].gen
== from_space
) &&
2573 ((page_table
[next_page
].allocated
== UNBOXED_PAGE_FLAG
)
2574 || (page_table
[next_page
].allocated
== BOXED_PAGE_FLAG
)) &&
2575 page_table
[next_page
].large_object
&&
2576 (page_table
[next_page
].first_object_offset
==
2577 -(next_page
- first_page
)*PAGE_BYTES
)) {
2578 /* It checks out OK, free the page. We don't need to both zeroing
2579 * pages as this should have been done before shrinking the
2580 * object. These pages shouldn't be write protected as they
2581 * should be zero filled. */
2582 gc_assert(page_table
[next_page
].write_protected
== 0);
2584 old_bytes_used
= page_table
[next_page
].bytes_used
;
2585 page_table
[next_page
].allocated
= FREE_PAGE_FLAG
;
2586 page_table
[next_page
].bytes_used
= 0;
2587 bytes_freed
+= old_bytes_used
;
2591 if ((bytes_freed
> 0) && gencgc_verbose
) {
2593 "/maybe_adjust_large_object() freed %d\n",
2597 generations
[from_space
].bytes_allocated
-= bytes_freed
;
2598 bytes_allocated
-= bytes_freed
;
2603 /* Take a possible pointer to a Lisp object and mark its page in the
2604 * page_table so that it will not be relocated during a GC.
2606 * This involves locating the page it points to, then backing up to
2607 * the start of its region, then marking all pages dont_move from there
2608 * up to the first page that's not full or has a different generation
2610 * It is assumed that all the page static flags have been cleared at
2611 * the start of a GC.
2613 * It is also assumed that the current gc_alloc() region has been
2614 * flushed and the tables updated. */
2617 preserve_pointer(void *addr
)
2619 page_index_t addr_page_index
= find_page_index(addr
);
2620 page_index_t first_page
;
2622 unsigned int region_allocation
;
2624 /* quick check 1: Address is quite likely to have been invalid. */
2625 if ((addr_page_index
== -1)
2626 || (page_table
[addr_page_index
].allocated
== FREE_PAGE_FLAG
)
2627 || (page_table
[addr_page_index
].bytes_used
== 0)
2628 || (page_table
[addr_page_index
].gen
!= from_space
)
2629 /* Skip if already marked dont_move. */
2630 || (page_table
[addr_page_index
].dont_move
!= 0))
2632 gc_assert(!(page_table
[addr_page_index
].allocated
&OPEN_REGION_PAGE_FLAG
));
2633 /* (Now that we know that addr_page_index is in range, it's
2634 * safe to index into page_table[] with it.) */
2635 region_allocation
= page_table
[addr_page_index
].allocated
;
2637 /* quick check 2: Check the offset within the page.
2640 if (((unsigned long)addr
& (PAGE_BYTES
- 1)) > page_table
[addr_page_index
].bytes_used
)
2643 /* Filter out anything which can't be a pointer to a Lisp object
2644 * (or, as a special case which also requires dont_move, a return
2645 * address referring to something in a CodeObject). This is
2646 * expensive but important, since it vastly reduces the
2647 * probability that random garbage will be bogusly interpreted as
2648 * a pointer which prevents a page from moving. */
2649 if (!(possibly_valid_dynamic_space_pointer(addr
)))
2652 /* Find the beginning of the region. Note that there may be
2653 * objects in the region preceding the one that we were passed a
2654 * pointer to: if this is the case, we will write-protect all the
2655 * previous objects' pages too. */
2658 /* I think this'd work just as well, but without the assertions.
2659 * -dan 2004.01.01 */
2661 find_page_index(page_address(addr_page_index
)+
2662 page_table
[addr_page_index
].first_object_offset
);
2664 first_page
= addr_page_index
;
2665 while (page_table
[first_page
].first_object_offset
!= 0) {
2667 /* Do some checks. */
2668 gc_assert(page_table
[first_page
].bytes_used
== PAGE_BYTES
);
2669 gc_assert(page_table
[first_page
].gen
== from_space
);
2670 gc_assert(page_table
[first_page
].allocated
== region_allocation
);
2674 /* Adjust any large objects before promotion as they won't be
2675 * copied after promotion. */
2676 if (page_table
[first_page
].large_object
) {
2677 maybe_adjust_large_object(page_address(first_page
));
2678 /* If a large object has shrunk then addr may now point to a
2679 * free area in which case it's ignored here. Note it gets
2680 * through the valid pointer test above because the tail looks
2682 if ((page_table
[addr_page_index
].allocated
== FREE_PAGE_FLAG
)
2683 || (page_table
[addr_page_index
].bytes_used
== 0)
2684 /* Check the offset within the page. */
2685 || (((unsigned long)addr
& (PAGE_BYTES
- 1))
2686 > page_table
[addr_page_index
].bytes_used
)) {
2688 "weird? ignore ptr 0x%x to freed area of large object\n",
2692 /* It may have moved to unboxed pages. */
2693 region_allocation
= page_table
[first_page
].allocated
;
2696 /* Now work forward until the end of this contiguous area is found,
2697 * marking all pages as dont_move. */
2698 for (i
= first_page
; ;i
++) {
2699 gc_assert(page_table
[i
].allocated
== region_allocation
);
2701 /* Mark the page static. */
2702 page_table
[i
].dont_move
= 1;
2704 /* Move the page to the new_space. XX I'd rather not do this
2705 * but the GC logic is not quite able to copy with the static
2706 * pages remaining in the from space. This also requires the
2707 * generation bytes_allocated counters be updated. */
2708 page_table
[i
].gen
= new_space
;
2709 generations
[new_space
].bytes_allocated
+= page_table
[i
].bytes_used
;
2710 generations
[from_space
].bytes_allocated
-= page_table
[i
].bytes_used
;
2712 /* It is essential that the pages are not write protected as
2713 * they may have pointers into the old-space which need
2714 * scavenging. They shouldn't be write protected at this
2716 gc_assert(!page_table
[i
].write_protected
);
2718 /* Check whether this is the last page in this contiguous block.. */
2719 if ((page_table
[i
].bytes_used
< PAGE_BYTES
)
2720 /* ..or it is PAGE_BYTES and is the last in the block */
2721 || (page_table
[i
+1].allocated
== FREE_PAGE_FLAG
)
2722 || (page_table
[i
+1].bytes_used
== 0) /* next page free */
2723 || (page_table
[i
+1].gen
!= from_space
) /* diff. gen */
2724 || (page_table
[i
+1].first_object_offset
== 0))
2728 /* Check that the page is now static. */
2729 gc_assert(page_table
[addr_page_index
].dont_move
!= 0);
2732 #endif // defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2735 /* If the given page is not write-protected, then scan it for pointers
2736 * to younger generations or the top temp. generation, if no
2737 * suspicious pointers are found then the page is write-protected.
2739 * Care is taken to check for pointers to the current gc_alloc()
2740 * region if it is a younger generation or the temp. generation. This
2741 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2742 * the gc_alloc_generation does not need to be checked as this is only
2743 * called from scavenge_generation() when the gc_alloc generation is
2744 * younger, so it just checks if there is a pointer to the current
2747 * We return 1 if the page was write-protected, else 0. */
2749 update_page_write_prot(page_index_t page
)
2751 generation_index_t gen
= page_table
[page
].gen
;
2754 void **page_addr
= (void **)page_address(page
);
2755 long num_words
= page_table
[page
].bytes_used
/ N_WORD_BYTES
;
2757 /* Shouldn't be a free page. */
2758 gc_assert(page_table
[page
].allocated
!= FREE_PAGE_FLAG
);
2759 gc_assert(page_table
[page
].bytes_used
!= 0);
2761 /* Skip if it's already write-protected, pinned, or unboxed */
2762 if (page_table
[page
].write_protected
2763 /* FIXME: What's the reason for not write-protecting pinned pages? */
2764 || page_table
[page
].dont_move
2765 || (page_table
[page
].allocated
& UNBOXED_PAGE_FLAG
))
2768 /* Scan the page for pointers to younger generations or the
2769 * top temp. generation. */
2771 for (j
= 0; j
< num_words
; j
++) {
2772 void *ptr
= *(page_addr
+j
);
2773 page_index_t index
= find_page_index(ptr
);
2775 /* Check that it's in the dynamic space */
2777 if (/* Does it point to a younger or the temp. generation? */
2778 ((page_table
[index
].allocated
!= FREE_PAGE_FLAG
)
2779 && (page_table
[index
].bytes_used
!= 0)
2780 && ((page_table
[index
].gen
< gen
)
2781 || (page_table
[index
].gen
== SCRATCH_GENERATION
)))
2783 /* Or does it point within a current gc_alloc() region? */
2784 || ((boxed_region
.start_addr
<= ptr
)
2785 && (ptr
<= boxed_region
.free_pointer
))
2786 || ((unboxed_region
.start_addr
<= ptr
)
2787 && (ptr
<= unboxed_region
.free_pointer
))) {
2794 /* Write-protect the page. */
2795 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2797 os_protect((void *)page_addr
,
2799 OS_VM_PROT_READ
|OS_VM_PROT_EXECUTE
);
2801 /* Note the page as protected in the page tables. */
2802 page_table
[page
].write_protected
= 1;
2808 /* Scavenge all generations from FROM to TO, inclusive, except for
2809 * new_space which needs special handling, as new objects may be
2810 * added which are not checked here - use scavenge_newspace generation.
2812 * Write-protected pages should not have any pointers to the
2813 * from_space so do need scavenging; thus write-protected pages are
2814 * not always scavenged. There is some code to check that these pages
2815 * are not written; but to check fully the write-protected pages need
2816 * to be scavenged by disabling the code to skip them.
2818 * Under the current scheme when a generation is GCed the younger
2819 * generations will be empty. So, when a generation is being GCed it
2820 * is only necessary to scavenge the older generations for pointers
2821 * not the younger. So a page that does not have pointers to younger
2822 * generations does not need to be scavenged.
2824 * The write-protection can be used to note pages that don't have
2825 * pointers to younger pages. But pages can be written without having
2826 * pointers to younger generations. After the pages are scavenged here
2827 * they can be scanned for pointers to younger generations and if
2828 * there are none the page can be write-protected.
2830 * One complication is when the newspace is the top temp. generation.
2832 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2833 * that none were written, which they shouldn't be as they should have
2834 * no pointers to younger generations. This breaks down for weak
2835 * pointers as the objects contain a link to the next and are written
2836 * if a weak pointer is scavenged. Still it's a useful check. */
2838 scavenge_generations(generation_index_t from
, generation_index_t to
)
2845 /* Clear the write_protected_cleared flags on all pages. */
2846 for (i
= 0; i
< page_table_pages
; i
++)
2847 page_table
[i
].write_protected_cleared
= 0;
2850 for (i
= 0; i
< last_free_page
; i
++) {
2851 generation_index_t generation
= page_table
[i
].gen
;
2852 if ((page_table
[i
].allocated
& BOXED_PAGE_FLAG
)
2853 && (page_table
[i
].bytes_used
!= 0)
2854 && (generation
!= new_space
)
2855 && (generation
>= from
)
2856 && (generation
<= to
)) {
2857 page_index_t last_page
,j
;
2858 int write_protected
=1;
2860 /* This should be the start of a region */
2861 gc_assert(page_table
[i
].first_object_offset
== 0);
2863 /* Now work forward until the end of the region */
2864 for (last_page
= i
; ; last_page
++) {
2866 write_protected
&& page_table
[last_page
].write_protected
;
2867 if ((page_table
[last_page
].bytes_used
< PAGE_BYTES
)
2868 /* Or it is PAGE_BYTES and is the last in the block */
2869 || (!(page_table
[last_page
+1].allocated
& BOXED_PAGE_FLAG
))
2870 || (page_table
[last_page
+1].bytes_used
== 0)
2871 || (page_table
[last_page
+1].gen
!= generation
)
2872 || (page_table
[last_page
+1].first_object_offset
== 0))
2875 if (!write_protected
) {
2876 scavenge(page_address(i
),
2877 (page_table
[last_page
].bytes_used
+
2878 (last_page
-i
)*PAGE_BYTES
)/N_WORD_BYTES
);
2880 /* Now scan the pages and write protect those that
2881 * don't have pointers to younger generations. */
2882 if (enable_page_protection
) {
2883 for (j
= i
; j
<= last_page
; j
++) {
2884 num_wp
+= update_page_write_prot(j
);
2887 if ((gencgc_verbose
> 1) && (num_wp
!= 0)) {
2889 "/write protected %d pages within generation %d\n",
2890 num_wp
, generation
));
2898 /* Check that none of the write_protected pages in this generation
2899 * have been written to. */
2900 for (i
= 0; i
< page_table_pages
; i
++) {
2901 if ((page_table
[i
].allocation
!= FREE_PAGE_FLAG
)
2902 && (page_table
[i
].bytes_used
!= 0)
2903 && (page_table
[i
].gen
== generation
)
2904 && (page_table
[i
].write_protected_cleared
!= 0)) {
2905 FSHOW((stderr
, "/scavenge_generation() %d\n", generation
));
2907 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2908 page_table
[i
].bytes_used
,
2909 page_table
[i
].first_object_offset
,
2910 page_table
[i
].dont_move
));
2911 lose("write to protected page %d in scavenge_generation()\n", i
);
2918 /* Scavenge a newspace generation. As it is scavenged new objects may
2919 * be allocated to it; these will also need to be scavenged. This
2920 * repeats until there are no more objects unscavenged in the
2921 * newspace generation.
2923 * To help improve the efficiency, areas written are recorded by
2924 * gc_alloc() and only these scavenged. Sometimes a little more will be
2925 * scavenged, but this causes no harm. An easy check is done that the
2926 * scavenged bytes equals the number allocated in the previous
2929 * Write-protected pages are not scanned except if they are marked
2930 * dont_move in which case they may have been promoted and still have
2931 * pointers to the from space.
2933 * Write-protected pages could potentially be written by alloc however
2934 * to avoid having to handle re-scavenging of write-protected pages
2935 * gc_alloc() does not write to write-protected pages.
2937 * New areas of objects allocated are recorded alternatively in the two
2938 * new_areas arrays below. */
2939 static struct new_area new_areas_1
[NUM_NEW_AREAS
];
2940 static struct new_area new_areas_2
[NUM_NEW_AREAS
];
2942 /* Do one full scan of the new space generation. This is not enough to
2943 * complete the job as new objects may be added to the generation in
2944 * the process which are not scavenged. */
2946 scavenge_newspace_generation_one_scan(generation_index_t generation
)
2951 "/starting one full scan of newspace generation %d\n",
2953 for (i
= 0; i
< last_free_page
; i
++) {
2954 /* Note that this skips over open regions when it encounters them. */
2955 if ((page_table
[i
].allocated
& BOXED_PAGE_FLAG
)
2956 && (page_table
[i
].bytes_used
!= 0)
2957 && (page_table
[i
].gen
== generation
)
2958 && ((page_table
[i
].write_protected
== 0)
2959 /* (This may be redundant as write_protected is now
2960 * cleared before promotion.) */
2961 || (page_table
[i
].dont_move
== 1))) {
2962 page_index_t last_page
;
2965 /* The scavenge will start at the first_object_offset of page i.
2967 * We need to find the full extent of this contiguous
2968 * block in case objects span pages.
2970 * Now work forward until the end of this contiguous area
2971 * is found. A small area is preferred as there is a
2972 * better chance of its pages being write-protected. */
2973 for (last_page
= i
; ;last_page
++) {
2974 /* If all pages are write-protected and movable,
2975 * then no need to scavenge */
2976 all_wp
=all_wp
&& page_table
[last_page
].write_protected
&&
2977 !page_table
[last_page
].dont_move
;
2979 /* Check whether this is the last page in this
2980 * contiguous block */
2981 if ((page_table
[last_page
].bytes_used
< PAGE_BYTES
)
2982 /* Or it is PAGE_BYTES and is the last in the block */
2983 || (!(page_table
[last_page
+1].allocated
& BOXED_PAGE_FLAG
))
2984 || (page_table
[last_page
+1].bytes_used
== 0)
2985 || (page_table
[last_page
+1].gen
!= generation
)
2986 || (page_table
[last_page
+1].first_object_offset
== 0))
2990 /* Do a limited check for write-protected pages. */
2994 size
= (page_table
[last_page
].bytes_used
2995 + (last_page
-i
)*PAGE_BYTES
2996 - page_table
[i
].first_object_offset
)/N_WORD_BYTES
;
2997 new_areas_ignore_page
= last_page
;
2999 scavenge(page_address(i
) +
3000 page_table
[i
].first_object_offset
,
3008 "/done with one full scan of newspace generation %d\n",
3012 /* Do a complete scavenge of the newspace generation. */
3014 scavenge_newspace_generation(generation_index_t generation
)
3018 /* the new_areas array currently being written to by gc_alloc() */
3019 struct new_area (*current_new_areas
)[] = &new_areas_1
;
3020 long current_new_areas_index
;
3022 /* the new_areas created by the previous scavenge cycle */
3023 struct new_area (*previous_new_areas
)[] = NULL
;
3024 long previous_new_areas_index
;
3026 /* Flush the current regions updating the tables. */
3027 gc_alloc_update_all_page_tables();
3029 /* Turn on the recording of new areas by gc_alloc(). */
3030 new_areas
= current_new_areas
;
3031 new_areas_index
= 0;
3033 /* Don't need to record new areas that get scavenged anyway during
3034 * scavenge_newspace_generation_one_scan. */
3035 record_new_objects
= 1;
3037 /* Start with a full scavenge. */
3038 scavenge_newspace_generation_one_scan(generation
);
3040 /* Record all new areas now. */
3041 record_new_objects
= 2;
3043 /* Give a chance to weak hash tables to make other objects live.
3044 * FIXME: The algorithm implemented here for weak hash table gcing
3045 * is O(W^2+N) as Bruno Haible warns in
3046 * http://www.haible.de/bruno/papers/cs/weak/WeakDatastructures-writeup.html
3047 * see "Implementation 2". */
3048 scav_weak_hash_tables();
3050 /* Flush the current regions updating the tables. */
3051 gc_alloc_update_all_page_tables();
3053 /* Grab new_areas_index. */
3054 current_new_areas_index
= new_areas_index
;
3057 "The first scan is finished; current_new_areas_index=%d.\n",
3058 current_new_areas_index));*/
3060 while (current_new_areas_index
> 0) {
3061 /* Move the current to the previous new areas */
3062 previous_new_areas
= current_new_areas
;
3063 previous_new_areas_index
= current_new_areas_index
;
3065 /* Scavenge all the areas in previous new areas. Any new areas
3066 * allocated are saved in current_new_areas. */
3068 /* Allocate an array for current_new_areas; alternating between
3069 * new_areas_1 and 2 */
3070 if (previous_new_areas
== &new_areas_1
)
3071 current_new_areas
= &new_areas_2
;
3073 current_new_areas
= &new_areas_1
;
3075 /* Set up for gc_alloc(). */
3076 new_areas
= current_new_areas
;
3077 new_areas_index
= 0;
3079 /* Check whether previous_new_areas had overflowed. */
3080 if (previous_new_areas_index
>= NUM_NEW_AREAS
) {
3082 /* New areas of objects allocated have been lost so need to do a
3083 * full scan to be sure! If this becomes a problem try
3084 * increasing NUM_NEW_AREAS. */
3086 SHOW("new_areas overflow, doing full scavenge");
3088 /* Don't need to record new areas that get scavenged
3089 * anyway during scavenge_newspace_generation_one_scan. */
3090 record_new_objects
= 1;
3092 scavenge_newspace_generation_one_scan(generation
);
3094 /* Record all new areas now. */
3095 record_new_objects
= 2;
3097 scav_weak_hash_tables();
3099 /* Flush the current regions updating the tables. */
3100 gc_alloc_update_all_page_tables();
3104 /* Work through previous_new_areas. */
3105 for (i
= 0; i
< previous_new_areas_index
; i
++) {
3106 long page
= (*previous_new_areas
)[i
].page
;
3107 long offset
= (*previous_new_areas
)[i
].offset
;
3108 long size
= (*previous_new_areas
)[i
].size
/ N_WORD_BYTES
;
3109 gc_assert((*previous_new_areas
)[i
].size
% N_WORD_BYTES
== 0);
3110 scavenge(page_address(page
)+offset
, size
);
3113 scav_weak_hash_tables();
3115 /* Flush the current regions updating the tables. */
3116 gc_alloc_update_all_page_tables();
3119 current_new_areas_index
= new_areas_index
;
3122 "The re-scan has finished; current_new_areas_index=%d.\n",
3123 current_new_areas_index));*/
3126 /* Turn off recording of areas allocated by gc_alloc(). */
3127 record_new_objects
= 0;
3130 /* Check that none of the write_protected pages in this generation
3131 * have been written to. */
3132 for (i
= 0; i
< page_table_pages
; i
++) {
3133 if ((page_table
[i
].allocation
!= FREE_PAGE_FLAG
)
3134 && (page_table
[i
].bytes_used
!= 0)
3135 && (page_table
[i
].gen
== generation
)
3136 && (page_table
[i
].write_protected_cleared
!= 0)
3137 && (page_table
[i
].dont_move
== 0)) {
3138 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d\n",
3139 i
, generation
, page_table
[i
].dont_move
);
3145 /* Un-write-protect all the pages in from_space. This is done at the
3146 * start of a GC else there may be many page faults while scavenging
3147 * the newspace (I've seen drive the system time to 99%). These pages
3148 * would need to be unprotected anyway before unmapping in
3149 * free_oldspace; not sure what effect this has on paging.. */
3151 unprotect_oldspace(void)
3155 for (i
= 0; i
< last_free_page
; i
++) {
3156 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
3157 && (page_table
[i
].bytes_used
!= 0)
3158 && (page_table
[i
].gen
== from_space
)) {
3161 page_start
= (void *)page_address(i
);
3163 /* Remove any write-protection. We should be able to rely
3164 * on the write-protect flag to avoid redundant calls. */
3165 if (page_table
[i
].write_protected
) {
3166 os_protect(page_start
, PAGE_BYTES
, OS_VM_PROT_ALL
);
3167 page_table
[i
].write_protected
= 0;
3173 /* Work through all the pages and free any in from_space. This
3174 * assumes that all objects have been copied or promoted to an older
3175 * generation. Bytes_allocated and the generation bytes_allocated
3176 * counter are updated. The number of bytes freed is returned. */
3180 long bytes_freed
= 0;
3181 page_index_t first_page
, last_page
;
3186 /* Find a first page for the next region of pages. */
3187 while ((first_page
< last_free_page
)
3188 && ((page_table
[first_page
].allocated
== FREE_PAGE_FLAG
)
3189 || (page_table
[first_page
].bytes_used
== 0)
3190 || (page_table
[first_page
].gen
!= from_space
)))
3193 if (first_page
>= last_free_page
)
3196 /* Find the last page of this region. */
3197 last_page
= first_page
;
3200 /* Free the page. */
3201 bytes_freed
+= page_table
[last_page
].bytes_used
;
3202 generations
[page_table
[last_page
].gen
].bytes_allocated
-=
3203 page_table
[last_page
].bytes_used
;
3204 page_table
[last_page
].allocated
= FREE_PAGE_FLAG
;
3205 page_table
[last_page
].bytes_used
= 0;
3207 /* Remove any write-protection. We should be able to rely
3208 * on the write-protect flag to avoid redundant calls. */
3210 void *page_start
= (void *)page_address(last_page
);
3212 if (page_table
[last_page
].write_protected
) {
3213 os_protect(page_start
, PAGE_BYTES
, OS_VM_PROT_ALL
);
3214 page_table
[last_page
].write_protected
= 0;
3219 while ((last_page
< last_free_page
)
3220 && (page_table
[last_page
].allocated
!= FREE_PAGE_FLAG
)
3221 && (page_table
[last_page
].bytes_used
!= 0)
3222 && (page_table
[last_page
].gen
== from_space
));
3224 #ifdef READ_PROTECT_FREE_PAGES
3225 os_protect(page_address(first_page
),
3226 PAGE_BYTES
*(last_page
-first_page
),
3229 first_page
= last_page
;
3230 } while (first_page
< last_free_page
);
3232 bytes_allocated
-= bytes_freed
;
3237 /* Print some information about a pointer at the given address. */
3239 print_ptr(lispobj
*addr
)
3241 /* If addr is in the dynamic space then out the page information. */
3242 page_index_t pi1
= find_page_index((void*)addr
);
3245 fprintf(stderr
," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3246 (unsigned long) addr
,
3248 page_table
[pi1
].allocated
,
3249 page_table
[pi1
].gen
,
3250 page_table
[pi1
].bytes_used
,
3251 page_table
[pi1
].first_object_offset
,
3252 page_table
[pi1
].dont_move
);
3253 fprintf(stderr
," %x %x %x %x (%x) %x %x %x %x\n",
3267 verify_space(lispobj
*start
, size_t words
)
3269 int is_in_dynamic_space
= (find_page_index((void*)start
) != -1);
3270 int is_in_readonly_space
=
3271 (READ_ONLY_SPACE_START
<= (unsigned long)start
&&
3272 (unsigned long)start
< SymbolValue(READ_ONLY_SPACE_FREE_POINTER
,0));
3276 lispobj thing
= *(lispobj
*)start
;
3278 if (is_lisp_pointer(thing
)) {
3279 page_index_t page_index
= find_page_index((void*)thing
);
3280 long to_readonly_space
=
3281 (READ_ONLY_SPACE_START
<= thing
&&
3282 thing
< SymbolValue(READ_ONLY_SPACE_FREE_POINTER
,0));
3283 long to_static_space
=
3284 (STATIC_SPACE_START
<= thing
&&
3285 thing
< SymbolValue(STATIC_SPACE_FREE_POINTER
,0));
3287 /* Does it point to the dynamic space? */
3288 if (page_index
!= -1) {
3289 /* If it's within the dynamic space it should point to a used
3290 * page. XX Could check the offset too. */
3291 if ((page_table
[page_index
].allocated
!= FREE_PAGE_FLAG
)
3292 && (page_table
[page_index
].bytes_used
== 0))
3293 lose ("Ptr %x @ %x sees free page.\n", thing
, start
);
3294 /* Check that it doesn't point to a forwarding pointer! */
3295 if (*((lispobj
*)native_pointer(thing
)) == 0x01) {
3296 lose("Ptr %x @ %x sees forwarding ptr.\n", thing
, start
);
3298 /* Check that its not in the RO space as it would then be a
3299 * pointer from the RO to the dynamic space. */
3300 if (is_in_readonly_space
) {
3301 lose("ptr to dynamic space %x from RO space %x\n",
3304 /* Does it point to a plausible object? This check slows
3305 * it down a lot (so it's commented out).
3307 * "a lot" is serious: it ate 50 minutes cpu time on
3308 * my duron 950 before I came back from lunch and
3311 * FIXME: Add a variable to enable this
3314 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3315 lose("ptr %x to invalid object %x\n", thing, start);
3319 /* Verify that it points to another valid space. */
3320 if (!to_readonly_space
&& !to_static_space
) {
3321 lose("Ptr %x @ %x sees junk.\n", thing
, start
);
3325 if (!(fixnump(thing
))) {
3327 switch(widetag_of(*start
)) {
3330 case SIMPLE_VECTOR_WIDETAG
:
3332 case COMPLEX_WIDETAG
:
3333 case SIMPLE_ARRAY_WIDETAG
:
3334 case COMPLEX_BASE_STRING_WIDETAG
:
3335 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
3336 case COMPLEX_CHARACTER_STRING_WIDETAG
:
3338 case COMPLEX_VECTOR_NIL_WIDETAG
:
3339 case COMPLEX_BIT_VECTOR_WIDETAG
:
3340 case COMPLEX_VECTOR_WIDETAG
:
3341 case COMPLEX_ARRAY_WIDETAG
:
3342 case CLOSURE_HEADER_WIDETAG
:
3343 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG
:
3344 case VALUE_CELL_HEADER_WIDETAG
:
3345 case SYMBOL_HEADER_WIDETAG
:
3346 case CHARACTER_WIDETAG
:
3347 #if N_WORD_BITS == 64
3348 case SINGLE_FLOAT_WIDETAG
:
3350 case UNBOUND_MARKER_WIDETAG
:
3355 case INSTANCE_HEADER_WIDETAG
:
3358 long ntotal
= HeaderValue(thing
);
3359 lispobj layout
= ((struct instance
*)start
)->slots
[0];
3364 nuntagged
= ((struct layout
*)native_pointer(layout
))->n_untagged_slots
;
3365 verify_space(start
+ 1, ntotal
- fixnum_value(nuntagged
));
3369 case CODE_HEADER_WIDETAG
:
3371 lispobj object
= *start
;
3373 long nheader_words
, ncode_words
, nwords
;
3375 struct simple_fun
*fheaderp
;
3377 code
= (struct code
*) start
;
3379 /* Check that it's not in the dynamic space.
3380 * FIXME: Isn't is supposed to be OK for code
3381 * objects to be in the dynamic space these days? */
3382 if (is_in_dynamic_space
3383 /* It's ok if it's byte compiled code. The trace
3384 * table offset will be a fixnum if it's x86
3385 * compiled code - check.
3387 * FIXME: #^#@@! lack of abstraction here..
3388 * This line can probably go away now that
3389 * there's no byte compiler, but I've got
3390 * too much to worry about right now to try
3391 * to make sure. -- WHN 2001-10-06 */
3392 && fixnump(code
->trace_table_offset
)
3393 /* Only when enabled */
3394 && verify_dynamic_code_check
) {
3396 "/code object at %x in the dynamic space\n",
3400 ncode_words
= fixnum_value(code
->code_size
);
3401 nheader_words
= HeaderValue(object
);
3402 nwords
= ncode_words
+ nheader_words
;
3403 nwords
= CEILING(nwords
, 2);
3404 /* Scavenge the boxed section of the code data block */
3405 verify_space(start
+ 1, nheader_words
- 1);
3407 /* Scavenge the boxed section of each function
3408 * object in the code data block. */
3409 fheaderl
= code
->entry_points
;
3410 while (fheaderl
!= NIL
) {
3412 (struct simple_fun
*) native_pointer(fheaderl
);
3413 gc_assert(widetag_of(fheaderp
->header
) == SIMPLE_FUN_HEADER_WIDETAG
);
3414 verify_space(&fheaderp
->name
, 1);
3415 verify_space(&fheaderp
->arglist
, 1);
3416 verify_space(&fheaderp
->type
, 1);
3417 fheaderl
= fheaderp
->next
;
3423 /* unboxed objects */
3424 case BIGNUM_WIDETAG
:
3425 #if N_WORD_BITS != 64
3426 case SINGLE_FLOAT_WIDETAG
:
3428 case DOUBLE_FLOAT_WIDETAG
:
3429 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3430 case LONG_FLOAT_WIDETAG
:
3432 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3433 case COMPLEX_SINGLE_FLOAT_WIDETAG
:
3435 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3436 case COMPLEX_DOUBLE_FLOAT_WIDETAG
:
3438 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3439 case COMPLEX_LONG_FLOAT_WIDETAG
:
3441 case SIMPLE_BASE_STRING_WIDETAG
:
3442 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
3443 case SIMPLE_CHARACTER_STRING_WIDETAG
:
3445 case SIMPLE_BIT_VECTOR_WIDETAG
:
3446 case SIMPLE_ARRAY_NIL_WIDETAG
:
3447 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG
:
3448 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG
:
3449 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG
:
3450 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG
:
3451 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG
:
3452 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG
:
3453 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
3454 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
:
3456 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG
:
3457 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
:
3458 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
3459 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
:
3461 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
3462 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
:
3464 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
3465 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
:
3467 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3468 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
:
3470 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3471 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
:
3473 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3474 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
:
3476 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3477 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
:
3479 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
3480 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
:
3482 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
3483 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
:
3485 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG
:
3486 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG
:
3487 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3488 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
:
3490 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3491 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
:
3493 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3494 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
:
3496 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3497 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
:
3500 case WEAK_POINTER_WIDETAG
:
3501 #ifdef LUTEX_WIDETAG
3504 count
= (sizetab
[widetag_of(*start
)])(start
);
3509 "/Unhandled widetag 0x%x at 0x%x\n",
3510 widetag_of(*start
), start
));
3524 /* FIXME: It would be nice to make names consistent so that
3525 * foo_size meant size *in* *bytes* instead of size in some
3526 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3527 * Some counts of lispobjs are called foo_count; it might be good
3528 * to grep for all foo_size and rename the appropriate ones to
3530 long read_only_space_size
=
3531 (lispobj
*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER
,0)
3532 - (lispobj
*)READ_ONLY_SPACE_START
;
3533 long static_space_size
=
3534 (lispobj
*)SymbolValue(STATIC_SPACE_FREE_POINTER
,0)
3535 - (lispobj
*)STATIC_SPACE_START
;
3537 for_each_thread(th
) {
3538 long binding_stack_size
=
3539 (lispobj
*)get_binding_stack_pointer(th
)
3540 - (lispobj
*)th
->binding_stack_start
;
3541 verify_space(th
->binding_stack_start
, binding_stack_size
);
3543 verify_space((lispobj
*)READ_ONLY_SPACE_START
, read_only_space_size
);
3544 verify_space((lispobj
*)STATIC_SPACE_START
, static_space_size
);
3548 verify_generation(generation_index_t generation
)
3552 for (i
= 0; i
< last_free_page
; i
++) {
3553 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
3554 && (page_table
[i
].bytes_used
!= 0)
3555 && (page_table
[i
].gen
== generation
)) {
3556 page_index_t last_page
;
3557 int region_allocation
= page_table
[i
].allocated
;
3559 /* This should be the start of a contiguous block */
3560 gc_assert(page_table
[i
].first_object_offset
== 0);
3562 /* Need to find the full extent of this contiguous block in case
3563 objects span pages. */
3565 /* Now work forward until the end of this contiguous area is
3567 for (last_page
= i
; ;last_page
++)
3568 /* Check whether this is the last page in this contiguous
3570 if ((page_table
[last_page
].bytes_used
< PAGE_BYTES
)
3571 /* Or it is PAGE_BYTES and is the last in the block */
3572 || (page_table
[last_page
+1].allocated
!= region_allocation
)
3573 || (page_table
[last_page
+1].bytes_used
== 0)
3574 || (page_table
[last_page
+1].gen
!= generation
)
3575 || (page_table
[last_page
+1].first_object_offset
== 0))
3578 verify_space(page_address(i
), (page_table
[last_page
].bytes_used
3579 + (last_page
-i
)*PAGE_BYTES
)/N_WORD_BYTES
);
3585 /* Check that all the free space is zero filled. */
3587 verify_zero_fill(void)
3591 for (page
= 0; page
< last_free_page
; page
++) {
3592 if (page_table
[page
].allocated
== FREE_PAGE_FLAG
) {
3593 /* The whole page should be zero filled. */
3594 long *start_addr
= (long *)page_address(page
);
3597 for (i
= 0; i
< size
; i
++) {
3598 if (start_addr
[i
] != 0) {
3599 lose("free page not zero at %x\n", start_addr
+ i
);
3603 long free_bytes
= PAGE_BYTES
- page_table
[page
].bytes_used
;
3604 if (free_bytes
> 0) {
3605 long *start_addr
= (long *)((unsigned long)page_address(page
)
3606 + page_table
[page
].bytes_used
);
3607 long size
= free_bytes
/ N_WORD_BYTES
;
3609 for (i
= 0; i
< size
; i
++) {
3610 if (start_addr
[i
] != 0) {
3611 lose("free region not zero at %x\n", start_addr
+ i
);
3619 /* External entry point for verify_zero_fill */
3621 gencgc_verify_zero_fill(void)
3623 /* Flush the alloc regions updating the tables. */
3624 gc_alloc_update_all_page_tables();
3625 SHOW("verifying zero fill");
3630 verify_dynamic_space(void)
3632 generation_index_t i
;
3634 for (i
= 0; i
<= HIGHEST_NORMAL_GENERATION
; i
++)
3635 verify_generation(i
);
3637 if (gencgc_enable_verify_zero_fill
)
3641 /* Write-protect all the dynamic boxed pages in the given generation. */
3643 write_protect_generation_pages(generation_index_t generation
)
3647 gc_assert(generation
< SCRATCH_GENERATION
);
3649 for (start
= 0; start
< last_free_page
; start
++) {
3650 if ((page_table
[start
].allocated
== BOXED_PAGE_FLAG
)
3651 && (page_table
[start
].bytes_used
!= 0)
3652 && !page_table
[start
].dont_move
3653 && (page_table
[start
].gen
== generation
)) {
3657 /* Note the page as protected in the page tables. */
3658 page_table
[start
].write_protected
= 1;
3660 for (last
= start
+ 1; last
< last_free_page
; last
++) {
3661 if ((page_table
[last
].allocated
!= BOXED_PAGE_FLAG
)
3662 || (page_table
[last
].bytes_used
== 0)
3663 || page_table
[last
].dont_move
3664 || (page_table
[last
].gen
!= generation
))
3666 page_table
[last
].write_protected
= 1;
3669 page_start
= (void *)page_address(start
);
3671 os_protect(page_start
,
3672 PAGE_BYTES
* (last
- start
),
3673 OS_VM_PROT_READ
| OS_VM_PROT_EXECUTE
);
3679 if (gencgc_verbose
> 1) {
3681 "/write protected %d of %d pages in generation %d\n",
3682 count_write_protect_generation_pages(generation
),
3683 count_generation_pages(generation
),
3688 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
3691 scavenge_control_stack()
3693 unsigned long control_stack_size
;
3695 /* This is going to be a big problem when we try to port threads
3697 struct thread
*th
= arch_os_get_current_thread();
3698 lispobj
*control_stack
=
3699 (lispobj
*)(th
->control_stack_start
);
3701 control_stack_size
= current_control_stack_pointer
- control_stack
;
3702 scavenge(control_stack
, control_stack_size
);
3705 /* Scavenging Interrupt Contexts */
3707 static int boxed_registers
[] = BOXED_REGISTERS
;
3710 scavenge_interrupt_context(os_context_t
* context
)
3716 unsigned long lip_offset
;
3717 int lip_register_pair
;
3719 unsigned long pc_code_offset
;
3721 #ifdef ARCH_HAS_LINK_REGISTER
3722 unsigned long lr_code_offset
;
3724 #ifdef ARCH_HAS_NPC_REGISTER
3725 unsigned long npc_code_offset
;
3729 /* Find the LIP's register pair and calculate it's offset */
3730 /* before we scavenge the context. */
3733 * I (RLT) think this is trying to find the boxed register that is
3734 * closest to the LIP address, without going past it. Usually, it's
3735 * reg_CODE or reg_LRA. But sometimes, nothing can be found.
3737 lip
= *os_context_register_addr(context
, reg_LIP
);
3738 lip_offset
= 0x7FFFFFFF;
3739 lip_register_pair
= -1;
3740 for (i
= 0; i
< (sizeof(boxed_registers
) / sizeof(int)); i
++) {
3745 index
= boxed_registers
[i
];
3746 reg
= *os_context_register_addr(context
, index
);
3747 if ((reg
& ~((1L<<N_LOWTAG_BITS
)-1)) <= lip
) {
3749 if (offset
< lip_offset
) {
3750 lip_offset
= offset
;
3751 lip_register_pair
= index
;
3755 #endif /* reg_LIP */
3757 /* Compute the PC's offset from the start of the CODE */
3759 pc_code_offset
= *os_context_pc_addr(context
) - *os_context_register_addr(context
, reg_CODE
);
3760 #ifdef ARCH_HAS_NPC_REGISTER
3761 npc_code_offset
= *os_context_npc_addr(context
) - *os_context_register_addr(context
, reg_CODE
);
3762 #endif /* ARCH_HAS_NPC_REGISTER */
3764 #ifdef ARCH_HAS_LINK_REGISTER
3766 *os_context_lr_addr(context
) -
3767 *os_context_register_addr(context
, reg_CODE
);
3770 /* Scanvenge all boxed registers in the context. */
3771 for (i
= 0; i
< (sizeof(boxed_registers
) / sizeof(int)); i
++) {
3775 index
= boxed_registers
[i
];
3776 foo
= *os_context_register_addr(context
, index
);
3778 *os_context_register_addr(context
, index
) = foo
;
3780 scavenge((lispobj
*) &(*os_context_register_addr(context
, index
)), 1);
3787 * But what happens if lip_register_pair is -1? *os_context_register_addr on Solaris
3788 * (see solaris_register_address in solaris-os.c) will return
3789 * &context->uc_mcontext.gregs[2]. But gregs[2] is REG_nPC. Is
3790 * that what we really want? My guess is that that is not what we
3791 * want, so if lip_register_pair is -1, we don't touch reg_LIP at
3792 * all. But maybe it doesn't really matter if LIP is trashed?
3794 if (lip_register_pair
>= 0) {
3795 *os_context_register_addr(context
, reg_LIP
) =
3796 *os_context_register_addr(context
, lip_register_pair
) + lip_offset
;
3798 #endif /* reg_LIP */
3800 /* Fix the PC if it was in from space */
3801 if (from_space_p(*os_context_pc_addr(context
)))
3802 *os_context_pc_addr(context
) = *os_context_register_addr(context
, reg_CODE
) + pc_code_offset
;
3804 #ifdef ARCH_HAS_LINK_REGISTER
3805 /* Fix the LR ditto; important if we're being called from
3806 * an assembly routine that expects to return using blr, otherwise
3808 if (from_space_p(*os_context_lr_addr(context
)))
3809 *os_context_lr_addr(context
) =
3810 *os_context_register_addr(context
, reg_CODE
) + lr_code_offset
;
3813 #ifdef ARCH_HAS_NPC_REGISTER
3814 if (from_space_p(*os_context_npc_addr(context
)))
3815 *os_context_npc_addr(context
) = *os_context_register_addr(context
, reg_CODE
) + npc_code_offset
;
3816 #endif /* ARCH_HAS_NPC_REGISTER */
3820 scavenge_interrupt_contexts(void)
3823 os_context_t
*context
;
3825 struct thread
*th
=arch_os_get_current_thread();
3827 index
= fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX
,0));
3829 #if defined(DEBUG_PRINT_CONTEXT_INDEX)
3830 printf("Number of active contexts: %d\n", index
);
3833 for (i
= 0; i
< index
; i
++) {
3834 context
= th
->interrupt_contexts
[i
];
3835 scavenge_interrupt_context(context
);
3841 #if defined(LISP_FEATURE_SB_THREAD)
3843 preserve_context_registers (os_context_t
*c
)
3846 /* On Darwin the signal context isn't a contiguous block of memory,
3847 * so just preserve_pointering its contents won't be sufficient.
3849 #if defined(LISP_FEATURE_DARWIN)
3850 #if defined LISP_FEATURE_X86
3851 preserve_pointer((void*)*os_context_register_addr(c
,reg_EAX
));
3852 preserve_pointer((void*)*os_context_register_addr(c
,reg_ECX
));
3853 preserve_pointer((void*)*os_context_register_addr(c
,reg_EDX
));
3854 preserve_pointer((void*)*os_context_register_addr(c
,reg_EBX
));
3855 preserve_pointer((void*)*os_context_register_addr(c
,reg_ESI
));
3856 preserve_pointer((void*)*os_context_register_addr(c
,reg_EDI
));
3857 preserve_pointer((void*)*os_context_pc_addr(c
));
3858 #elif defined LISP_FEATURE_X86_64
3859 preserve_pointer((void*)*os_context_register_addr(c
,reg_RAX
));
3860 preserve_pointer((void*)*os_context_register_addr(c
,reg_RCX
));
3861 preserve_pointer((void*)*os_context_register_addr(c
,reg_RDX
));
3862 preserve_pointer((void*)*os_context_register_addr(c
,reg_RBX
));
3863 preserve_pointer((void*)*os_context_register_addr(c
,reg_RSI
));
3864 preserve_pointer((void*)*os_context_register_addr(c
,reg_RDI
));
3865 preserve_pointer((void*)*os_context_register_addr(c
,reg_R8
));
3866 preserve_pointer((void*)*os_context_register_addr(c
,reg_R9
));
3867 preserve_pointer((void*)*os_context_register_addr(c
,reg_R10
));
3868 preserve_pointer((void*)*os_context_register_addr(c
,reg_R11
));
3869 preserve_pointer((void*)*os_context_register_addr(c
,reg_R12
));
3870 preserve_pointer((void*)*os_context_register_addr(c
,reg_R13
));
3871 preserve_pointer((void*)*os_context_register_addr(c
,reg_R14
));
3872 preserve_pointer((void*)*os_context_register_addr(c
,reg_R15
));
3873 preserve_pointer((void*)*os_context_pc_addr(c
));
3875 #error "preserve_context_registers needs to be tweaked for non-x86 Darwin"
3878 for(ptr
= ((void **)(c
+1))-1; ptr
>=(void **)c
; ptr
--) {
3879 preserve_pointer(*ptr
);
3884 /* Garbage collect a generation. If raise is 0 then the remains of the
3885 * generation are not raised to the next generation. */
3887 garbage_collect_generation(generation_index_t generation
, int raise
)
3889 unsigned long bytes_freed
;
3891 unsigned long static_space_size
;
3892 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
3895 gc_assert(generation
<= HIGHEST_NORMAL_GENERATION
);
3897 /* The oldest generation can't be raised. */
3898 gc_assert((generation
!= HIGHEST_NORMAL_GENERATION
) || (raise
== 0));
3900 /* Check if weak hash tables were processed in the previous GC. */
3901 gc_assert(weak_hash_tables
== NULL
);
3903 /* Initialize the weak pointer list. */
3904 weak_pointers
= NULL
;
3906 #ifdef LUTEX_WIDETAG
3907 unmark_lutexes(generation
);
3910 /* When a generation is not being raised it is transported to a
3911 * temporary generation (NUM_GENERATIONS), and lowered when
3912 * done. Set up this new generation. There should be no pages
3913 * allocated to it yet. */
3915 gc_assert(generations
[SCRATCH_GENERATION
].bytes_allocated
== 0);
3918 /* Set the global src and dest. generations */
3919 from_space
= generation
;
3921 new_space
= generation
+1;
3923 new_space
= SCRATCH_GENERATION
;
3925 /* Change to a new space for allocation, resetting the alloc_start_page */
3926 gc_alloc_generation
= new_space
;
3927 generations
[new_space
].alloc_start_page
= 0;
3928 generations
[new_space
].alloc_unboxed_start_page
= 0;
3929 generations
[new_space
].alloc_large_start_page
= 0;
3930 generations
[new_space
].alloc_large_unboxed_start_page
= 0;
3932 /* Before any pointers are preserved, the dont_move flags on the
3933 * pages need to be cleared. */
3934 for (i
= 0; i
< last_free_page
; i
++)
3935 if(page_table
[i
].gen
==from_space
)
3936 page_table
[i
].dont_move
= 0;
3938 /* Un-write-protect the old-space pages. This is essential for the
3939 * promoted pages as they may contain pointers into the old-space
3940 * which need to be scavenged. It also helps avoid unnecessary page
3941 * faults as forwarding pointers are written into them. They need to
3942 * be un-protected anyway before unmapping later. */
3943 unprotect_oldspace();
3945 /* Scavenge the stacks' conservative roots. */
3947 /* there are potentially two stacks for each thread: the main
3948 * stack, which may contain Lisp pointers, and the alternate stack.
3949 * We don't ever run Lisp code on the altstack, but it may
3950 * host a sigcontext with lisp objects in it */
3952 /* what we need to do: (1) find the stack pointer for the main
3953 * stack; scavenge it (2) find the interrupt context on the
3954 * alternate stack that might contain lisp values, and scavenge
3957 /* we assume that none of the preceding applies to the thread that
3958 * initiates GC. If you ever call GC from inside an altstack
3959 * handler, you will lose. */
3961 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
3962 /* And if we're saving a core, there's no point in being conservative. */
3963 if (conservative_stack
) {
3964 for_each_thread(th
) {
3966 void **esp
=(void **)-1;
3967 #ifdef LISP_FEATURE_SB_THREAD
3969 if(th
==arch_os_get_current_thread()) {
3970 /* Somebody is going to burn in hell for this, but casting
3971 * it in two steps shuts gcc up about strict aliasing. */
3972 esp
= (void **)((void *)&raise
);
3975 free
=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX
,th
));
3976 for(i
=free
-1;i
>=0;i
--) {
3977 os_context_t
*c
=th
->interrupt_contexts
[i
];
3978 esp1
= (void **) *os_context_register_addr(c
,reg_SP
);
3979 if (esp1
>=(void **)th
->control_stack_start
&&
3980 esp1
<(void **)th
->control_stack_end
) {
3981 if(esp1
<esp
) esp
=esp1
;
3982 preserve_context_registers(c
);
3987 esp
= (void **)((void *)&raise
);
3989 for (ptr
= ((void **)th
->control_stack_end
)-1; ptr
>= esp
; ptr
--) {
3990 preserve_pointer(*ptr
);
3997 if (gencgc_verbose
> 1) {
3998 long num_dont_move_pages
= count_dont_move_pages();
4000 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
4001 num_dont_move_pages
,
4002 num_dont_move_pages
* PAGE_BYTES
);
4006 /* Scavenge all the rest of the roots. */
4008 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
4010 * If not x86, we need to scavenge the interrupt context(s) and the
4013 scavenge_interrupt_contexts();
4014 scavenge_control_stack();
4017 /* Scavenge the Lisp functions of the interrupt handlers, taking
4018 * care to avoid SIG_DFL and SIG_IGN. */
4019 for (i
= 0; i
< NSIG
; i
++) {
4020 union interrupt_handler handler
= interrupt_handlers
[i
];
4021 if (!ARE_SAME_HANDLER(handler
.c
, SIG_IGN
) &&
4022 !ARE_SAME_HANDLER(handler
.c
, SIG_DFL
)) {
4023 scavenge((lispobj
*)(interrupt_handlers
+ i
), 1);
4026 /* Scavenge the binding stacks. */
4029 for_each_thread(th
) {
4030 long len
= (lispobj
*)get_binding_stack_pointer(th
) -
4031 th
->binding_stack_start
;
4032 scavenge((lispobj
*) th
->binding_stack_start
,len
);
4033 #ifdef LISP_FEATURE_SB_THREAD
4034 /* do the tls as well */
4035 len
=fixnum_value(SymbolValue(FREE_TLS_INDEX
,0)) -
4036 (sizeof (struct thread
))/(sizeof (lispobj
));
4037 scavenge((lispobj
*) (th
+1),len
);
4042 /* The original CMU CL code had scavenge-read-only-space code
4043 * controlled by the Lisp-level variable
4044 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
4045 * wasn't documented under what circumstances it was useful or
4046 * safe to turn it on, so it's been turned off in SBCL. If you
4047 * want/need this functionality, and can test and document it,
4048 * please submit a patch. */
4050 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE
) != NIL
) {
4051 unsigned long read_only_space_size
=
4052 (lispobj
*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER
) -
4053 (lispobj
*)READ_ONLY_SPACE_START
;
4055 "/scavenge read only space: %d bytes\n",
4056 read_only_space_size
* sizeof(lispobj
)));
4057 scavenge( (lispobj
*) READ_ONLY_SPACE_START
, read_only_space_size
);
4061 /* Scavenge static space. */
4063 (lispobj
*)SymbolValue(STATIC_SPACE_FREE_POINTER
,0) -
4064 (lispobj
*)STATIC_SPACE_START
;
4065 if (gencgc_verbose
> 1) {
4067 "/scavenge static space: %d bytes\n",
4068 static_space_size
* sizeof(lispobj
)));
4070 scavenge( (lispobj
*) STATIC_SPACE_START
, static_space_size
);
4072 /* All generations but the generation being GCed need to be
4073 * scavenged. The new_space generation needs special handling as
4074 * objects may be moved in - it is handled separately below. */
4075 scavenge_generations(generation
+1, PSEUDO_STATIC_GENERATION
);
4077 /* Finally scavenge the new_space generation. Keep going until no
4078 * more objects are moved into the new generation */
4079 scavenge_newspace_generation(new_space
);
4081 /* FIXME: I tried reenabling this check when debugging unrelated
4082 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
4083 * Since the current GC code seems to work well, I'm guessing that
4084 * this debugging code is just stale, but I haven't tried to
4085 * figure it out. It should be figured out and then either made to
4086 * work or just deleted. */
4087 #define RESCAN_CHECK 0
4089 /* As a check re-scavenge the newspace once; no new objects should
4092 long old_bytes_allocated
= bytes_allocated
;
4093 long bytes_allocated
;
4095 /* Start with a full scavenge. */
4096 scavenge_newspace_generation_one_scan(new_space
);
4098 /* Flush the current regions, updating the tables. */
4099 gc_alloc_update_all_page_tables();
4101 bytes_allocated
= bytes_allocated
- old_bytes_allocated
;
4103 if (bytes_allocated
!= 0) {
4104 lose("Rescan of new_space allocated %d more bytes.\n",
4110 scan_weak_hash_tables();
4111 scan_weak_pointers();
4113 /* Flush the current regions, updating the tables. */
4114 gc_alloc_update_all_page_tables();
4116 /* Free the pages in oldspace, but not those marked dont_move. */
4117 bytes_freed
= free_oldspace();
4119 /* If the GC is not raising the age then lower the generation back
4120 * to its normal generation number */
4122 for (i
= 0; i
< last_free_page
; i
++)
4123 if ((page_table
[i
].bytes_used
!= 0)
4124 && (page_table
[i
].gen
== SCRATCH_GENERATION
))
4125 page_table
[i
].gen
= generation
;
4126 gc_assert(generations
[generation
].bytes_allocated
== 0);
4127 generations
[generation
].bytes_allocated
=
4128 generations
[SCRATCH_GENERATION
].bytes_allocated
;
4129 generations
[SCRATCH_GENERATION
].bytes_allocated
= 0;
4132 /* Reset the alloc_start_page for generation. */
4133 generations
[generation
].alloc_start_page
= 0;
4134 generations
[generation
].alloc_unboxed_start_page
= 0;
4135 generations
[generation
].alloc_large_start_page
= 0;
4136 generations
[generation
].alloc_large_unboxed_start_page
= 0;
4138 if (generation
>= verify_gens
) {
4142 verify_dynamic_space();
4145 /* Set the new gc trigger for the GCed generation. */
4146 generations
[generation
].gc_trigger
=
4147 generations
[generation
].bytes_allocated
4148 + generations
[generation
].bytes_consed_between_gc
;
4151 generations
[generation
].num_gc
= 0;
4153 ++generations
[generation
].num_gc
;
4155 #ifdef LUTEX_WIDETAG
4156 reap_lutexes(generation
);
4158 move_lutexes(generation
, generation
+1);
4162 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
4164 update_dynamic_space_free_pointer(void)
4166 page_index_t last_page
= -1, i
;
4168 for (i
= 0; i
< last_free_page
; i
++)
4169 if ((page_table
[i
].allocated
!= FREE_PAGE_FLAG
)
4170 && (page_table
[i
].bytes_used
!= 0))
4173 last_free_page
= last_page
+1;
4175 set_alloc_pointer((lispobj
)(((char *)heap_base
) + last_free_page
*PAGE_BYTES
));
4176 return 0; /* dummy value: return something ... */
4180 remap_free_pages (page_index_t from
, page_index_t to
)
4182 page_index_t first_page
, last_page
;
4184 for (first_page
= from
; first_page
<= to
; first_page
++) {
4185 if (page_table
[first_page
].allocated
!= FREE_PAGE_FLAG
||
4186 page_table
[first_page
].need_to_zero
== 0) {
4190 last_page
= first_page
+ 1;
4191 while (page_table
[last_page
].allocated
== FREE_PAGE_FLAG
&&
4193 page_table
[last_page
].need_to_zero
== 1) {
4197 /* There's a mysterious Solaris/x86 problem with using mmap
4198 * tricks for memory zeroing. See sbcl-devel thread
4199 * "Re: patch: standalone executable redux".
4201 #if defined(LISP_FEATURE_SUNOS)
4202 zero_pages(first_page
, last_page
-1);
4204 zero_pages_with_mmap(first_page
, last_page
-1);
4207 first_page
= last_page
;
4211 generation_index_t small_generation_limit
= 1;
4213 /* GC all generations newer than last_gen, raising the objects in each
4214 * to the next older generation - we finish when all generations below
4215 * last_gen are empty. Then if last_gen is due for a GC, or if
4216 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
4217 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
4219 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
4220 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
4222 collect_garbage(generation_index_t last_gen
)
4224 generation_index_t gen
= 0, i
;
4227 /* The largest value of last_free_page seen since the time
4228 * remap_free_pages was called. */
4229 static page_index_t high_water_mark
= 0;
4231 FSHOW((stderr
, "/entering collect_garbage(%d)\n", last_gen
));
4235 if (last_gen
> HIGHEST_NORMAL_GENERATION
+1) {
4237 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
4242 /* Flush the alloc regions updating the tables. */
4243 gc_alloc_update_all_page_tables();
4245 /* Verify the new objects created by Lisp code. */
4246 if (pre_verify_gen_0
) {
4247 FSHOW((stderr
, "pre-checking generation 0\n"));
4248 verify_generation(0);
4251 if (gencgc_verbose
> 1)
4252 print_generation_stats(0);
4255 /* Collect the generation. */
4257 if (gen
>= gencgc_oldest_gen_to_gc
) {
4258 /* Never raise the oldest generation. */
4263 || (generations
[gen
].num_gc
>= generations
[gen
].trigger_age
);
4266 if (gencgc_verbose
> 1) {
4268 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
4271 generations
[gen
].bytes_allocated
,
4272 generations
[gen
].gc_trigger
,
4273 generations
[gen
].num_gc
));
4276 /* If an older generation is being filled, then update its
4279 generations
[gen
+1].cum_sum_bytes_allocated
+=
4280 generations
[gen
+1].bytes_allocated
;
4283 garbage_collect_generation(gen
, raise
);
4285 /* Reset the memory age cum_sum. */
4286 generations
[gen
].cum_sum_bytes_allocated
= 0;
4288 if (gencgc_verbose
> 1) {
4289 FSHOW((stderr
, "GC of generation %d finished:\n", gen
));
4290 print_generation_stats(0);
4294 } while ((gen
<= gencgc_oldest_gen_to_gc
)
4295 && ((gen
< last_gen
)
4296 || ((gen
<= gencgc_oldest_gen_to_gc
)
4298 && (generations
[gen
].bytes_allocated
4299 > generations
[gen
].gc_trigger
)
4300 && (gen_av_mem_age(gen
)
4301 > generations
[gen
].min_av_mem_age
))));
4303 /* Now if gen-1 was raised all generations before gen are empty.
4304 * If it wasn't raised then all generations before gen-1 are empty.
4306 * Now objects within this gen's pages cannot point to younger
4307 * generations unless they are written to. This can be exploited
4308 * by write-protecting the pages of gen; then when younger
4309 * generations are GCed only the pages which have been written
4314 gen_to_wp
= gen
- 1;
4316 /* There's not much point in WPing pages in generation 0 as it is
4317 * never scavenged (except promoted pages). */
4318 if ((gen_to_wp
> 0) && enable_page_protection
) {
4319 /* Check that they are all empty. */
4320 for (i
= 0; i
< gen_to_wp
; i
++) {
4321 if (generations
[i
].bytes_allocated
)
4322 lose("trying to write-protect gen. %d when gen. %d nonempty\n",
4325 write_protect_generation_pages(gen_to_wp
);
4328 /* Set gc_alloc() back to generation 0. The current regions should
4329 * be flushed after the above GCs. */
4330 gc_assert((boxed_region
.free_pointer
- boxed_region
.start_addr
) == 0);
4331 gc_alloc_generation
= 0;
4333 /* Save the high-water mark before updating last_free_page */
4334 if (last_free_page
> high_water_mark
)
4335 high_water_mark
= last_free_page
;
4337 update_dynamic_space_free_pointer();
4339 auto_gc_trigger
= bytes_allocated
+ bytes_consed_between_gcs
;
4341 fprintf(stderr
,"Next gc when %ld bytes have been consed\n",
4344 /* If we did a big GC (arbitrarily defined as gen > 1), release memory
4347 if (gen
> small_generation_limit
) {
4348 if (last_free_page
> high_water_mark
)
4349 high_water_mark
= last_free_page
;
4350 remap_free_pages(0, high_water_mark
);
4351 high_water_mark
= 0;
4356 SHOW("returning from collect_garbage");
4359 /* This is called by Lisp PURIFY when it is finished. All live objects
4360 * will have been moved to the RO and Static heaps. The dynamic space
4361 * will need a full re-initialization. We don't bother having Lisp
4362 * PURIFY flush the current gc_alloc() region, as the page_tables are
4363 * re-initialized, and every page is zeroed to be sure. */
4369 if (gencgc_verbose
> 1)
4370 SHOW("entering gc_free_heap");
4372 for (page
= 0; page
< page_table_pages
; page
++) {
4373 /* Skip free pages which should already be zero filled. */
4374 if (page_table
[page
].allocated
!= FREE_PAGE_FLAG
) {
4375 void *page_start
, *addr
;
4377 /* Mark the page free. The other slots are assumed invalid
4378 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
4379 * should not be write-protected -- except that the
4380 * generation is used for the current region but it sets
4382 page_table
[page
].allocated
= FREE_PAGE_FLAG
;
4383 page_table
[page
].bytes_used
= 0;
4385 #ifndef LISP_FEATURE_WIN32 /* Pages already zeroed on win32? Not sure about this change. */
4386 /* Zero the page. */
4387 page_start
= (void *)page_address(page
);
4389 /* First, remove any write-protection. */
4390 os_protect(page_start
, PAGE_BYTES
, OS_VM_PROT_ALL
);
4391 page_table
[page
].write_protected
= 0;
4393 os_invalidate(page_start
,PAGE_BYTES
);
4394 addr
= os_validate(page_start
,PAGE_BYTES
);
4395 if (addr
== NULL
|| addr
!= page_start
) {
4396 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x\n",
4401 page_table
[page
].write_protected
= 0;
4403 } else if (gencgc_zero_check_during_free_heap
) {
4404 /* Double-check that the page is zero filled. */
4407 gc_assert(page_table
[page
].allocated
== FREE_PAGE_FLAG
);
4408 gc_assert(page_table
[page
].bytes_used
== 0);
4409 page_start
= (long *)page_address(page
);
4410 for (i
=0; i
<1024; i
++) {
4411 if (page_start
[i
] != 0) {
4412 lose("free region not zero at %x\n", page_start
+ i
);
4418 bytes_allocated
= 0;
4420 /* Initialize the generations. */
4421 for (page
= 0; page
< NUM_GENERATIONS
; page
++) {
4422 generations
[page
].alloc_start_page
= 0;
4423 generations
[page
].alloc_unboxed_start_page
= 0;
4424 generations
[page
].alloc_large_start_page
= 0;
4425 generations
[page
].alloc_large_unboxed_start_page
= 0;
4426 generations
[page
].bytes_allocated
= 0;
4427 generations
[page
].gc_trigger
= 2000000;
4428 generations
[page
].num_gc
= 0;
4429 generations
[page
].cum_sum_bytes_allocated
= 0;
4430 generations
[page
].lutexes
= NULL
;
4433 if (gencgc_verbose
> 1)
4434 print_generation_stats(0);
4436 /* Initialize gc_alloc(). */
4437 gc_alloc_generation
= 0;
4439 gc_set_region_empty(&boxed_region
);
4440 gc_set_region_empty(&unboxed_region
);
4443 set_alloc_pointer((lispobj
)((char *)heap_base
));
4445 if (verify_after_free_heap
) {
4446 /* Check whether purify has left any bad pointers. */
4448 SHOW("checking after free_heap\n");
4458 /* Compute the number of pages needed for the dynamic space.
4459 * Dynamic space size should be aligned on page size. */
4460 page_table_pages
= dynamic_space_size
/PAGE_BYTES
;
4461 gc_assert(dynamic_space_size
== (size_t) page_table_pages
*PAGE_BYTES
);
4463 page_table
= calloc(page_table_pages
, sizeof(struct page
));
4464 gc_assert(page_table
);
4467 scavtab
[WEAK_POINTER_WIDETAG
] = scav_weak_pointer
;
4468 transother
[SIMPLE_ARRAY_WIDETAG
] = trans_boxed_large
;
4470 #ifdef LUTEX_WIDETAG
4471 scavtab
[LUTEX_WIDETAG
] = scav_lutex
;
4472 transother
[LUTEX_WIDETAG
] = trans_lutex
;
4473 sizetab
[LUTEX_WIDETAG
] = size_lutex
;
4476 heap_base
= (void*)DYNAMIC_SPACE_START
;
4478 /* Initialize each page structure. */
4479 for (i
= 0; i
< page_table_pages
; i
++) {
4480 /* Initialize all pages as free. */
4481 page_table
[i
].allocated
= FREE_PAGE_FLAG
;
4482 page_table
[i
].bytes_used
= 0;
4484 /* Pages are not write-protected at startup. */
4485 page_table
[i
].write_protected
= 0;
4488 bytes_allocated
= 0;
4490 /* Initialize the generations.
4492 * FIXME: very similar to code in gc_free_heap(), should be shared */
4493 for (i
= 0; i
< NUM_GENERATIONS
; i
++) {
4494 generations
[i
].alloc_start_page
= 0;
4495 generations
[i
].alloc_unboxed_start_page
= 0;
4496 generations
[i
].alloc_large_start_page
= 0;
4497 generations
[i
].alloc_large_unboxed_start_page
= 0;
4498 generations
[i
].bytes_allocated
= 0;
4499 generations
[i
].gc_trigger
= 2000000;
4500 generations
[i
].num_gc
= 0;
4501 generations
[i
].cum_sum_bytes_allocated
= 0;
4502 /* the tune-able parameters */
4503 generations
[i
].bytes_consed_between_gc
= 2000000;
4504 generations
[i
].trigger_age
= 1;
4505 generations
[i
].min_av_mem_age
= 0.75;
4506 generations
[i
].lutexes
= NULL
;
4509 /* Initialize gc_alloc. */
4510 gc_alloc_generation
= 0;
4511 gc_set_region_empty(&boxed_region
);
4512 gc_set_region_empty(&unboxed_region
);
4517 /* Pick up the dynamic space from after a core load.
4519 * The ALLOCATION_POINTER points to the end of the dynamic space.
4523 gencgc_pickup_dynamic(void)
4525 page_index_t page
= 0;
4526 long alloc_ptr
= get_alloc_pointer();
4527 lispobj
*prev
=(lispobj
*)page_address(page
);
4528 generation_index_t gen
= PSEUDO_STATIC_GENERATION
;
4531 lispobj
*first
,*ptr
= (lispobj
*)page_address(page
);
4532 page_table
[page
].allocated
= BOXED_PAGE_FLAG
;
4533 page_table
[page
].gen
= gen
;
4534 page_table
[page
].bytes_used
= PAGE_BYTES
;
4535 page_table
[page
].large_object
= 0;
4536 page_table
[page
].write_protected
= 0;
4537 page_table
[page
].write_protected_cleared
= 0;
4538 page_table
[page
].dont_move
= 0;
4539 page_table
[page
].need_to_zero
= 1;
4541 if (!gencgc_partial_pickup
) {
4542 first
=gc_search_space(prev
,(ptr
+2)-prev
,ptr
);
4543 if(ptr
== first
) prev
=ptr
;
4544 page_table
[page
].first_object_offset
=
4545 (void *)prev
- page_address(page
);
4548 } while ((long)page_address(page
) < alloc_ptr
);
4550 #ifdef LUTEX_WIDETAG
4551 /* Lutexes have been registered in generation 0 by coreparse, and
4552 * need to be moved to the right one manually.
4554 move_lutexes(0, PSEUDO_STATIC_GENERATION
);
4557 last_free_page
= page
;
4559 generations
[gen
].bytes_allocated
= PAGE_BYTES
*page
;
4560 bytes_allocated
= PAGE_BYTES
*page
;
4562 gc_alloc_update_all_page_tables();
4563 write_protect_generation_pages(gen
);
4567 gc_initialize_pointers(void)
4569 gencgc_pickup_dynamic();
4575 /* alloc(..) is the external interface for memory allocation. It
4576 * allocates to generation 0. It is not called from within the garbage
4577 * collector as it is only external uses that need the check for heap
4578 * size (GC trigger) and to disable the interrupts (interrupts are
4579 * always disabled during a GC).
4581 * The vops that call alloc(..) assume that the returned space is zero-filled.
4582 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4584 * The check for a GC trigger is only performed when the current
4585 * region is full, so in most cases it's not needed. */
4590 struct thread
*thread
=arch_os_get_current_thread();
4591 struct alloc_region
*region
=
4592 #ifdef LISP_FEATURE_SB_THREAD
4593 thread
? &(thread
->alloc_region
) : &boxed_region
;
4597 #ifndef LISP_FEATURE_WIN32
4598 lispobj alloc_signal
;
4601 void *new_free_pointer
;
4603 gc_assert(nbytes
>0);
4605 /* Check for alignment allocation problems. */
4606 gc_assert((((unsigned long)region
->free_pointer
& LOWTAG_MASK
) == 0)
4607 && ((nbytes
& LOWTAG_MASK
) == 0));
4611 /* there are a few places in the C code that allocate data in the
4612 * heap before Lisp starts. This is before interrupts are enabled,
4613 * so we don't need to check for pseudo-atomic */
4614 #ifdef LISP_FEATURE_SB_THREAD
4615 if(!get_psuedo_atomic_atomic(th
)) {
4617 fprintf(stderr
, "fatal error in thread 0x%x, tid=%ld\n",
4619 __asm__("movl %fs,%0" : "=r" (fs
) : );
4620 fprintf(stderr
, "fs is %x, th->tls_cookie=%x \n",
4621 debug_get_fs(),th
->tls_cookie
);
4622 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4625 gc_assert(get_pseudo_atomic_atomic(th
));
4629 /* maybe we can do this quickly ... */
4630 new_free_pointer
= region
->free_pointer
+ nbytes
;
4631 if (new_free_pointer
<= region
->end_addr
) {
4632 new_obj
= (void*)(region
->free_pointer
);
4633 region
->free_pointer
= new_free_pointer
;
4634 return(new_obj
); /* yup */
4637 /* we have to go the long way around, it seems. Check whether
4638 * we should GC in the near future
4640 if (auto_gc_trigger
&& bytes_allocated
> auto_gc_trigger
) {
4641 gc_assert(get_pseudo_atomic_atomic(thread
));
4642 /* Don't flood the system with interrupts if the need to gc is
4643 * already noted. This can happen for example when SUB-GC
4644 * allocates or after a gc triggered in a WITHOUT-GCING. */
4645 if (SymbolValue(GC_PENDING
,thread
) == NIL
) {
4646 /* set things up so that GC happens when we finish the PA
4648 SetSymbolValue(GC_PENDING
,T
,thread
);
4649 if (SymbolValue(GC_INHIBIT
,thread
) == NIL
)
4650 set_pseudo_atomic_interrupted(thread
);
4653 new_obj
= gc_alloc_with_region(nbytes
,0,region
,0);
4655 #ifndef LISP_FEATURE_WIN32
4656 alloc_signal
= SymbolValue(ALLOC_SIGNAL
,thread
);
4657 if ((alloc_signal
& FIXNUM_TAG_MASK
) == 0) {
4658 if ((signed long) alloc_signal
<= 0) {
4659 #ifdef LISP_FEATURE_SB_THREAD
4660 kill_thread_safely(thread
->os_thread
, SIGPROF
);
4665 SetSymbolValue(ALLOC_SIGNAL
,
4666 alloc_signal
- (1 << N_FIXNUM_TAG_BITS
),
4676 * shared support for the OS-dependent signal handlers which
4677 * catch GENCGC-related write-protect violations
4680 void unhandled_sigmemoryfault(void* addr
);
4682 /* Depending on which OS we're running under, different signals might
4683 * be raised for a violation of write protection in the heap. This
4684 * function factors out the common generational GC magic which needs
4685 * to invoked in this case, and should be called from whatever signal
4686 * handler is appropriate for the OS we're running under.
4688 * Return true if this signal is a normal generational GC thing that
4689 * we were able to handle, or false if it was abnormal and control
4690 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4693 gencgc_handle_wp_violation(void* fault_addr
)
4695 page_index_t page_index
= find_page_index(fault_addr
);
4697 #ifdef QSHOW_SIGNALS
4698 FSHOW((stderr
, "heap WP violation? fault_addr=%x, page_index=%d\n",
4699 fault_addr
, page_index
));
4702 /* Check whether the fault is within the dynamic space. */
4703 if (page_index
== (-1)) {
4705 /* It can be helpful to be able to put a breakpoint on this
4706 * case to help diagnose low-level problems. */
4707 unhandled_sigmemoryfault(fault_addr
);
4709 /* not within the dynamic space -- not our responsibility */
4713 if (page_table
[page_index
].write_protected
) {
4714 /* Unprotect the page. */
4715 os_protect(page_address(page_index
), PAGE_BYTES
, OS_VM_PROT_ALL
);
4716 page_table
[page_index
].write_protected_cleared
= 1;
4717 page_table
[page_index
].write_protected
= 0;
4719 /* The only acceptable reason for this signal on a heap
4720 * access is that GENCGC write-protected the page.
4721 * However, if two CPUs hit a wp page near-simultaneously,
4722 * we had better not have the second one lose here if it
4723 * does this test after the first one has already set wp=0
4725 if(page_table
[page_index
].write_protected_cleared
!= 1)
4726 lose("fault in heap page %d not marked as write-protected\nboxed_region.first_page: %d, boxed_region.last_page %d\n",
4727 page_index
, boxed_region
.first_page
, boxed_region
.last_page
);
4729 /* Don't worry, we can handle it. */
4733 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4734 * it's not just a case of the program hitting the write barrier, and
4735 * are about to let Lisp deal with it. It's basically just a
4736 * convenient place to set a gdb breakpoint. */
4738 unhandled_sigmemoryfault(void *addr
)
4741 void gc_alloc_update_all_page_tables(void)
4743 /* Flush the alloc regions updating the tables. */
4746 gc_alloc_update_page_tables(0, &th
->alloc_region
);
4747 gc_alloc_update_page_tables(1, &unboxed_region
);
4748 gc_alloc_update_page_tables(0, &boxed_region
);
4752 gc_set_region_empty(struct alloc_region
*region
)
4754 region
->first_page
= 0;
4755 region
->last_page
= -1;
4756 region
->start_addr
= page_address(0);
4757 region
->free_pointer
= page_address(0);
4758 region
->end_addr
= page_address(0);
4762 zero_all_free_pages()
4766 for (i
= 0; i
< last_free_page
; i
++) {
4767 if (page_table
[i
].allocated
== FREE_PAGE_FLAG
) {
4768 #ifdef READ_PROTECT_FREE_PAGES
4769 os_protect(page_address(i
),
4778 /* Things to do before doing a final GC before saving a core (without
4781 * + Pages in large_object pages aren't moved by the GC, so we need to
4782 * unset that flag from all pages.
4783 * + The pseudo-static generation isn't normally collected, but it seems
4784 * reasonable to collect it at least when saving a core. So move the
4785 * pages to a normal generation.
4788 prepare_for_final_gc ()
4791 for (i
= 0; i
< last_free_page
; i
++) {
4792 page_table
[i
].large_object
= 0;
4793 if (page_table
[i
].gen
== PSEUDO_STATIC_GENERATION
) {
4794 int used
= page_table
[i
].bytes_used
;
4795 page_table
[i
].gen
= HIGHEST_NORMAL_GENERATION
;
4796 generations
[PSEUDO_STATIC_GENERATION
].bytes_allocated
-= used
;
4797 generations
[HIGHEST_NORMAL_GENERATION
].bytes_allocated
+= used
;
4803 /* Do a non-conservative GC, and then save a core with the initial
4804 * function being set to the value of the static symbol
4805 * SB!VM:RESTART-LISP-FUNCTION */
4807 gc_and_save(char *filename
, int prepend_runtime
)
4810 void *runtime_bytes
= NULL
;
4811 size_t runtime_size
;
4813 file
= prepare_to_save(filename
, prepend_runtime
, &runtime_bytes
,
4818 conservative_stack
= 0;
4820 /* The filename might come from Lisp, and be moved by the now
4821 * non-conservative GC. */
4822 filename
= strdup(filename
);
4824 /* Collect twice: once into relatively high memory, and then back
4825 * into low memory. This compacts the retained data into the lower
4826 * pages, minimizing the size of the core file.
4828 prepare_for_final_gc();
4829 gencgc_alloc_start_page
= last_free_page
;
4830 collect_garbage(HIGHEST_NORMAL_GENERATION
+1);
4832 prepare_for_final_gc();
4833 gencgc_alloc_start_page
= -1;
4834 collect_garbage(HIGHEST_NORMAL_GENERATION
+1);
4836 if (prepend_runtime
)
4837 save_runtime_to_filehandle(file
, runtime_bytes
, runtime_size
);
4839 /* The dumper doesn't know that pages need to be zeroed before use. */
4840 zero_all_free_pages();
4841 save_to_filehandle(file
, filename
, SymbolValue(RESTART_LISP_FUNCTION
,0),
4843 /* Oops. Save still managed to fail. Since we've mangled the stack
4844 * beyond hope, there's not much we can do.
4845 * (beyond FUNCALLing RESTART_LISP_FUNCTION, but I suspect that's
4846 * going to be rather unsatisfactory too... */
4847 lose("Attempt to save core after non-conservative GC failed.\n");