2 * GENerational Conservative Garbage Collector for SBCL x86
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>.
36 #include "interrupt.h"
42 #include "gc-internal.h"
44 #include "genesis/vector.h"
45 #include "genesis/weak-pointer.h"
46 #include "genesis/simple-fun.h"
48 /* assembly language stub that executes trap_PendingInterrupt */
49 void do_pending_interrupt(void);
51 /* forward declarations */
52 long gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed);
53 static void gencgc_pickup_dynamic(void);
54 boolean interrupt_maybe_gc_int(int, siginfo_t *, void *);
61 /* the number of actual generations. (The number of 'struct
62 * generation' objects is one more than this, because one object
63 * serves as scratch when GC'ing.) */
64 #define NUM_GENERATIONS 6
66 /* Should we use page protection to help avoid the scavenging of pages
67 * that don't have pointers to younger generations? */
68 boolean enable_page_protection = 1;
70 /* Should we unmap a page and re-mmap it to have it zero filled? */
71 #if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
72 /* comment from cmucl-2.4.8: This can waste a lot of swap on FreeBSD
73 * so don't unmap there.
75 * The CMU CL comment didn't specify a version, but was probably an
76 * old version of FreeBSD (pre-4.0), so this might no longer be true.
77 * OTOH, if it is true, this behavior might exist on OpenBSD too, so
78 * for now we don't unmap there either. -- WHN 2001-04-07 */
79 boolean gencgc_unmap_zero = 0;
81 boolean gencgc_unmap_zero = 1;
84 /* the minimum size (in bytes) for a large object*/
85 unsigned large_object_size = 4 * PAGE_BYTES;
94 /* the verbosity level. All non-error messages are disabled at level 0;
95 * and only a few rare messages are printed at level 1. */
97 unsigned gencgc_verbose = 1;
99 unsigned gencgc_verbose = 0;
102 /* FIXME: At some point enable the various error-checking things below
103 * and see what they say. */
105 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
106 * Set verify_gens to NUM_GENERATIONS to disable this kind of check. */
107 int verify_gens = NUM_GENERATIONS;
109 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
110 boolean pre_verify_gen_0 = 0;
112 /* Should we check for bad pointers after gc_free_heap is called
113 * from Lisp PURIFY? */
114 boolean verify_after_free_heap = 0;
116 /* Should we print a note when code objects are found in the dynamic space
117 * during a heap verify? */
118 boolean verify_dynamic_code_check = 0;
120 /* Should we check code objects for fixup errors after they are transported? */
121 boolean check_code_fixups = 0;
123 /* Should we check that newly allocated regions are zero filled? */
124 boolean gencgc_zero_check = 0;
126 /* Should we check that the free space is zero filled? */
127 boolean gencgc_enable_verify_zero_fill = 0;
129 /* Should we check that free pages are zero filled during gc_free_heap
130 * called after Lisp PURIFY? */
131 boolean gencgc_zero_check_during_free_heap = 0;
134 * GC structures and variables
137 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
138 unsigned long bytes_allocated = 0;
139 extern unsigned long bytes_consed_between_gcs; /* gc-common.c */
140 unsigned long auto_gc_trigger = 0;
142 /* the source and destination generations. These are set before a GC starts
148 /* An array of page structures is statically allocated.
149 * This helps quickly map between an address its page structure.
150 * NUM_PAGES is set from the size of the dynamic space. */
151 struct page page_table[NUM_PAGES];
153 /* To map addresses to page structures the address of the first page
155 static void *heap_base = NULL;
157 #if N_WORD_BITS == 32
158 #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG
159 #elif N_WORD_BITS == 64
160 #define SIMPLE_ARRAY_WORD_WIDETAG SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
163 /* Calculate the start address for the given page number. */
165 page_address(long page_num)
167 return (heap_base + (page_num * PAGE_BYTES));
170 /* Find the page index within the page_table for the given
171 * address. Return -1 on failure. */
173 find_page_index(void *addr)
175 long index = addr-heap_base;
178 index = ((unsigned long)index)/PAGE_BYTES;
179 if (index < NUM_PAGES)
186 /* a structure to hold the state of a generation */
189 /* the first page that gc_alloc() checks on its next call */
190 long alloc_start_page;
192 /* the first page that gc_alloc_unboxed() checks on its next call */
193 long alloc_unboxed_start_page;
195 /* the first page that gc_alloc_large (boxed) considers on its next
196 * call. (Although it always allocates after the boxed_region.) */
197 long alloc_large_start_page;
199 /* the first page that gc_alloc_large (unboxed) considers on its
200 * next call. (Although it always allocates after the
201 * current_unboxed_region.) */
202 long alloc_large_unboxed_start_page;
204 /* the bytes allocated to this generation */
205 long bytes_allocated;
207 /* the number of bytes at which to trigger a GC */
210 /* to calculate a new level for gc_trigger */
211 long bytes_consed_between_gc;
213 /* the number of GCs since the last raise */
216 /* the average age after which a GC will raise objects to the
220 /* the cumulative sum of the bytes allocated to this generation. It is
221 * cleared after a GC on this generations, and update before new
222 * objects are added from a GC of a younger generation. Dividing by
223 * the bytes_allocated will give the average age of the memory in
224 * this generation since its last GC. */
225 long cum_sum_bytes_allocated;
227 /* a minimum average memory age before a GC will occur helps
228 * prevent a GC when a large number of new live objects have been
229 * added, in which case a GC could be a waste of time */
230 double min_av_mem_age;
232 /* the number of actual generations. (The number of 'struct
233 * generation' objects is one more than this, because one object
234 * serves as scratch when GC'ing.) */
235 #define NUM_GENERATIONS 6
237 /* an array of generation structures. There needs to be one more
238 * generation structure than actual generations as the oldest
239 * generation is temporarily raised then lowered. */
240 struct generation generations[NUM_GENERATIONS+1];
242 /* the oldest generation that is will currently be GCed by default.
243 * Valid values are: 0, 1, ... (NUM_GENERATIONS-1)
245 * The default of (NUM_GENERATIONS-1) enables GC on all generations.
247 * Setting this to 0 effectively disables the generational nature of
248 * the GC. In some applications generational GC may not be useful
249 * because there are no long-lived objects.
251 * An intermediate value could be handy after moving long-lived data
252 * into an older generation so an unnecessary GC of this long-lived
253 * data can be avoided. */
254 unsigned int gencgc_oldest_gen_to_gc = NUM_GENERATIONS-1;
256 /* The maximum free page in the heap is maintained and used to update
257 * ALLOCATION_POINTER which is used by the room function to limit its
258 * search of the heap. XX Gencgc obviously needs to be better
259 * integrated with the Lisp code. */
260 static long last_free_page;
262 /* This lock is to prevent multiple threads from simultaneously
263 * allocating new regions which overlap each other. Note that the
264 * majority of GC is single-threaded, but alloc() may be called from
265 * >1 thread at a time and must be thread-safe. This lock must be
266 * seized before all accesses to generations[] or to parts of
267 * page_table[] that other threads may want to see */
269 static lispobj free_pages_lock=0;
273 * miscellaneous heap functions
276 /* Count the number of pages which are write-protected within the
277 * given generation. */
279 count_write_protect_generation_pages(int generation)
284 for (i = 0; i < last_free_page; i++)
285 if ((page_table[i].allocated != FREE_PAGE_FLAG)
286 && (page_table[i].gen == generation)
287 && (page_table[i].write_protected == 1))
292 /* Count the number of pages within the given generation. */
294 count_generation_pages(int generation)
299 for (i = 0; i < last_free_page; i++)
300 if ((page_table[i].allocated != 0)
301 && (page_table[i].gen == generation))
308 count_dont_move_pages(void)
312 for (i = 0; i < last_free_page; i++) {
313 if ((page_table[i].allocated != 0) && (page_table[i].dont_move != 0)) {
321 /* Work through the pages and add up the number of bytes used for the
322 * given generation. */
324 count_generation_bytes_allocated (int gen)
328 for (i = 0; i < last_free_page; i++) {
329 if ((page_table[i].allocated != 0) && (page_table[i].gen == gen))
330 result += page_table[i].bytes_used;
335 /* Return the average age of the memory in a generation. */
337 gen_av_mem_age(int gen)
339 if (generations[gen].bytes_allocated == 0)
343 ((double)generations[gen].cum_sum_bytes_allocated)
344 / ((double)generations[gen].bytes_allocated);
347 void fpu_save(int *); /* defined in x86-assem.S */
348 void fpu_restore(int *); /* defined in x86-assem.S */
349 /* The verbose argument controls how much to print: 0 for normal
350 * level of detail; 1 for debugging. */
352 print_generation_stats(int verbose) /* FIXME: should take FILE argument */
357 /* This code uses the FP instructions which may be set up for Lisp
358 * so they need to be saved and reset for C. */
361 /* number of generations to print */
363 gens = NUM_GENERATIONS+1;
365 gens = NUM_GENERATIONS;
367 /* Print the heap stats. */
369 " Gen Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
371 for (i = 0; i < gens; i++) {
375 int large_boxed_cnt = 0;
376 int large_unboxed_cnt = 0;
379 for (j = 0; j < last_free_page; j++)
380 if (page_table[j].gen == i) {
382 /* Count the number of boxed pages within the given
384 if (page_table[j].allocated & BOXED_PAGE_FLAG) {
385 if (page_table[j].large_object)
390 if(page_table[j].dont_move) pinned_cnt++;
391 /* Count the number of unboxed pages within the given
393 if (page_table[j].allocated & UNBOXED_PAGE_FLAG) {
394 if (page_table[j].large_object)
401 gc_assert(generations[i].bytes_allocated
402 == count_generation_bytes_allocated(i));
404 " %1d: %5d %5d %5d %5d %5d %8d %5d %8d %4d %3d %7.4f\n",
406 boxed_cnt, unboxed_cnt, large_boxed_cnt, large_unboxed_cnt,
408 generations[i].bytes_allocated,
409 (count_generation_pages(i)*PAGE_BYTES
410 - generations[i].bytes_allocated),
411 generations[i].gc_trigger,
412 count_write_protect_generation_pages(i),
413 generations[i].num_gc,
416 fprintf(stderr," Total bytes allocated=%ld\n", bytes_allocated);
418 fpu_restore(fpu_state);
422 * allocation routines
426 * To support quick and inline allocation, regions of memory can be
427 * allocated and then allocated from with just a free pointer and a
428 * check against an end address.
430 * Since objects can be allocated to spaces with different properties
431 * e.g. boxed/unboxed, generation, ages; there may need to be many
432 * allocation regions.
434 * Each allocation region may be start within a partly used page. Many
435 * features of memory use are noted on a page wise basis, e.g. the
436 * generation; so if a region starts within an existing allocated page
437 * it must be consistent with this page.
439 * During the scavenging of the newspace, objects will be transported
440 * into an allocation region, and pointers updated to point to this
441 * allocation region. It is possible that these pointers will be
442 * scavenged again before the allocation region is closed, e.g. due to
443 * trans_list which jumps all over the place to cleanup the list. It
444 * is important to be able to determine properties of all objects
445 * pointed to when scavenging, e.g to detect pointers to the oldspace.
446 * Thus it's important that the allocation regions have the correct
447 * properties set when allocated, and not just set when closed. The
448 * region allocation routines return regions with the specified
449 * properties, and grab all the pages, setting their properties
450 * appropriately, except that the amount used is not known.
452 * These regions are used to support quicker allocation using just a
453 * free pointer. The actual space used by the region is not reflected
454 * in the pages tables until it is closed. It can't be scavenged until
457 * When finished with the region it should be closed, which will
458 * update the page tables for the actual space used returning unused
459 * space. Further it may be noted in the new regions which is
460 * necessary when scavenging the newspace.
462 * Large objects may be allocated directly without an allocation
463 * region, the page tables are updated immediately.
465 * Unboxed objects don't contain pointers to other objects and so
466 * don't need scavenging. Further they can't contain pointers to
467 * younger generations so WP is not needed. By allocating pages to
468 * unboxed objects the whole page never needs scavenging or
469 * write-protecting. */
471 /* We are only using two regions at present. Both are for the current
472 * newspace generation. */
473 struct alloc_region boxed_region;
474 struct alloc_region unboxed_region;
476 /* The generation currently being allocated to. */
477 static int gc_alloc_generation;
479 /* Find a new region with room for at least the given number of bytes.
481 * It starts looking at the current generation's alloc_start_page. So
482 * may pick up from the previous region if there is enough space. This
483 * keeps the allocation contiguous when scavenging the newspace.
485 * The alloc_region should have been closed by a call to
486 * gc_alloc_update_page_tables(), and will thus be in an empty state.
488 * To assist the scavenging functions write-protected pages are not
489 * used. Free pages should not be write-protected.
491 * It is critical to the conservative GC that the start of regions be
492 * known. To help achieve this only small regions are allocated at a
495 * During scavenging, pointers may be found to within the current
496 * region and the page generation must be set so that pointers to the
497 * from space can be recognized. Therefore the generation of pages in
498 * the region are set to gc_alloc_generation. To prevent another
499 * allocation call using the same pages, all the pages in the region
500 * are allocated, although they will initially be empty.
503 gc_alloc_new_region(long nbytes, int unboxed, struct alloc_region *alloc_region)
512 "/alloc_new_region for %d bytes from gen %d\n",
513 nbytes, gc_alloc_generation));
516 /* Check that the region is in a reset state. */
517 gc_assert((alloc_region->first_page == 0)
518 && (alloc_region->last_page == -1)
519 && (alloc_region->free_pointer == alloc_region->end_addr));
520 get_spinlock(&free_pages_lock,(long) alloc_region);
523 generations[gc_alloc_generation].alloc_unboxed_start_page;
526 generations[gc_alloc_generation].alloc_start_page;
528 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
529 bytes_found=(PAGE_BYTES - page_table[first_page].bytes_used)
530 + PAGE_BYTES*(last_page-first_page);
532 /* Set up the alloc_region. */
533 alloc_region->first_page = first_page;
534 alloc_region->last_page = last_page;
535 alloc_region->start_addr = page_table[first_page].bytes_used
536 + page_address(first_page);
537 alloc_region->free_pointer = alloc_region->start_addr;
538 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
540 /* Set up the pages. */
542 /* The first page may have already been in use. */
543 if (page_table[first_page].bytes_used == 0) {
545 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
547 page_table[first_page].allocated = BOXED_PAGE_FLAG;
548 page_table[first_page].gen = gc_alloc_generation;
549 page_table[first_page].large_object = 0;
550 page_table[first_page].first_object_offset = 0;
554 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
556 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
557 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
559 gc_assert(page_table[first_page].gen == gc_alloc_generation);
560 gc_assert(page_table[first_page].large_object == 0);
562 for (i = first_page+1; i <= last_page; i++) {
564 page_table[i].allocated = UNBOXED_PAGE_FLAG;
566 page_table[i].allocated = BOXED_PAGE_FLAG;
567 page_table[i].gen = gc_alloc_generation;
568 page_table[i].large_object = 0;
569 /* This may not be necessary for unboxed regions (think it was
571 page_table[i].first_object_offset =
572 alloc_region->start_addr - page_address(i);
573 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
575 /* Bump up last_free_page. */
576 if (last_page+1 > last_free_page) {
577 last_free_page = last_page+1;
578 SetSymbolValue(ALLOCATION_POINTER,
579 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),
582 release_spinlock(&free_pages_lock);
584 /* we can do this after releasing free_pages_lock */
585 if (gencgc_zero_check) {
587 for (p = (long *)alloc_region->start_addr;
588 p < (long *)alloc_region->end_addr; p++) {
590 /* KLUDGE: It would be nice to use %lx and explicit casts
591 * (long) in code like this, so that it is less likely to
592 * break randomly when running on a machine with different
593 * word sizes. -- WHN 19991129 */
594 lose("The new region at %x is not zero.", p);
601 /* If the record_new_objects flag is 2 then all new regions created
604 * If it's 1 then then it is only recorded if the first page of the
605 * current region is <= new_areas_ignore_page. This helps avoid
606 * unnecessary recording when doing full scavenge pass.
608 * The new_object structure holds the page, byte offset, and size of
609 * new regions of objects. Each new area is placed in the array of
610 * these structures pointer to by new_areas. new_areas_index holds the
611 * offset into new_areas.
613 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
614 * later code must detect this and handle it, probably by doing a full
615 * scavenge of a generation. */
616 #define NUM_NEW_AREAS 512
617 static int record_new_objects = 0;
618 static long new_areas_ignore_page;
624 static struct new_area (*new_areas)[];
625 static long new_areas_index;
628 /* Add a new area to new_areas. */
630 add_new_area(long first_page, long offset, long size)
632 unsigned new_area_start,c;
635 /* Ignore if full. */
636 if (new_areas_index >= NUM_NEW_AREAS)
639 switch (record_new_objects) {
643 if (first_page > new_areas_ignore_page)
652 new_area_start = PAGE_BYTES*first_page + offset;
654 /* Search backwards for a prior area that this follows from. If
655 found this will save adding a new area. */
656 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
658 PAGE_BYTES*((*new_areas)[i].page)
659 + (*new_areas)[i].offset
660 + (*new_areas)[i].size;
662 "/add_new_area S1 %d %d %d %d\n",
663 i, c, new_area_start, area_end));*/
664 if (new_area_start == area_end) {
666 "/adding to [%d] %d %d %d with %d %d %d:\n",
668 (*new_areas)[i].page,
669 (*new_areas)[i].offset,
670 (*new_areas)[i].size,
674 (*new_areas)[i].size += size;
679 (*new_areas)[new_areas_index].page = first_page;
680 (*new_areas)[new_areas_index].offset = offset;
681 (*new_areas)[new_areas_index].size = size;
683 "/new_area %d page %d offset %d size %d\n",
684 new_areas_index, first_page, offset, size));*/
687 /* Note the max new_areas used. */
688 if (new_areas_index > max_new_areas)
689 max_new_areas = new_areas_index;
692 /* Update the tables for the alloc_region. The region may be added to
695 * When done the alloc_region is set up so that the next quick alloc
696 * will fail safely and thus a new region will be allocated. Further
697 * it is safe to try to re-update the page table of this reset
700 gc_alloc_update_page_tables(int unboxed, struct alloc_region *alloc_region)
706 long orig_first_page_bytes_used;
711 first_page = alloc_region->first_page;
713 /* Catch an unused alloc_region. */
714 if ((first_page == 0) && (alloc_region->last_page == -1))
717 next_page = first_page+1;
719 get_spinlock(&free_pages_lock,(long) alloc_region);
720 if (alloc_region->free_pointer != alloc_region->start_addr) {
721 /* some bytes were allocated in the region */
722 orig_first_page_bytes_used = page_table[first_page].bytes_used;
724 gc_assert(alloc_region->start_addr == (page_address(first_page) + page_table[first_page].bytes_used));
726 /* All the pages used need to be updated */
728 /* Update the first page. */
730 /* If the page was free then set up the gen, and
731 * first_object_offset. */
732 if (page_table[first_page].bytes_used == 0)
733 gc_assert(page_table[first_page].first_object_offset == 0);
734 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
737 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
739 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
740 gc_assert(page_table[first_page].gen == gc_alloc_generation);
741 gc_assert(page_table[first_page].large_object == 0);
745 /* Calculate the number of bytes used in this page. This is not
746 * always the number of new bytes, unless it was free. */
748 if ((bytes_used = (alloc_region->free_pointer - page_address(first_page)))>PAGE_BYTES) {
749 bytes_used = PAGE_BYTES;
752 page_table[first_page].bytes_used = bytes_used;
753 byte_cnt += bytes_used;
756 /* All the rest of the pages should be free. We need to set their
757 * first_object_offset pointer to the start of the region, and set
760 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
762 gc_assert(page_table[next_page].allocated==UNBOXED_PAGE_FLAG);
764 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
765 gc_assert(page_table[next_page].bytes_used == 0);
766 gc_assert(page_table[next_page].gen == gc_alloc_generation);
767 gc_assert(page_table[next_page].large_object == 0);
769 gc_assert(page_table[next_page].first_object_offset ==
770 alloc_region->start_addr - page_address(next_page));
772 /* Calculate the number of bytes used in this page. */
774 if ((bytes_used = (alloc_region->free_pointer
775 - page_address(next_page)))>PAGE_BYTES) {
776 bytes_used = PAGE_BYTES;
779 page_table[next_page].bytes_used = bytes_used;
780 byte_cnt += bytes_used;
785 region_size = alloc_region->free_pointer - alloc_region->start_addr;
786 bytes_allocated += region_size;
787 generations[gc_alloc_generation].bytes_allocated += region_size;
789 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
791 /* Set the generations alloc restart page to the last page of
794 generations[gc_alloc_generation].alloc_unboxed_start_page =
797 generations[gc_alloc_generation].alloc_start_page = next_page-1;
799 /* Add the region to the new_areas if requested. */
801 add_new_area(first_page,orig_first_page_bytes_used, region_size);
805 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
807 gc_alloc_generation));
810 /* There are no bytes allocated. Unallocate the first_page if
811 * there are 0 bytes_used. */
812 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
813 if (page_table[first_page].bytes_used == 0)
814 page_table[first_page].allocated = FREE_PAGE_FLAG;
817 /* Unallocate any unused pages. */
818 while (next_page <= alloc_region->last_page) {
819 gc_assert(page_table[next_page].bytes_used == 0);
820 page_table[next_page].allocated = FREE_PAGE_FLAG;
823 release_spinlock(&free_pages_lock);
824 /* alloc_region is per-thread, we're ok to do this unlocked */
825 gc_set_region_empty(alloc_region);
828 static inline void *gc_quick_alloc(long nbytes);
830 /* Allocate a possibly large object. */
832 gc_alloc_large(long nbytes, int unboxed, struct alloc_region *alloc_region)
836 long orig_first_page_bytes_used;
842 get_spinlock(&free_pages_lock,(long) alloc_region);
846 generations[gc_alloc_generation].alloc_large_unboxed_start_page;
848 first_page = generations[gc_alloc_generation].alloc_large_start_page;
850 if (first_page <= alloc_region->last_page) {
851 first_page = alloc_region->last_page+1;
854 last_page=gc_find_freeish_pages(&first_page,nbytes,unboxed);
856 gc_assert(first_page > alloc_region->last_page);
858 generations[gc_alloc_generation].alloc_large_unboxed_start_page =
861 generations[gc_alloc_generation].alloc_large_start_page = last_page;
863 /* Set up the pages. */
864 orig_first_page_bytes_used = page_table[first_page].bytes_used;
866 /* If the first page was free then set up the gen, and
867 * first_object_offset. */
868 if (page_table[first_page].bytes_used == 0) {
870 page_table[first_page].allocated = UNBOXED_PAGE_FLAG;
872 page_table[first_page].allocated = BOXED_PAGE_FLAG;
873 page_table[first_page].gen = gc_alloc_generation;
874 page_table[first_page].first_object_offset = 0;
875 page_table[first_page].large_object = 1;
879 gc_assert(page_table[first_page].allocated == UNBOXED_PAGE_FLAG);
881 gc_assert(page_table[first_page].allocated == BOXED_PAGE_FLAG);
882 gc_assert(page_table[first_page].gen == gc_alloc_generation);
883 gc_assert(page_table[first_page].large_object == 1);
887 /* Calc. the number of bytes used in this page. This is not
888 * always the number of new bytes, unless it was free. */
890 if ((bytes_used = nbytes+orig_first_page_bytes_used) > PAGE_BYTES) {
891 bytes_used = PAGE_BYTES;
894 page_table[first_page].bytes_used = bytes_used;
895 byte_cnt += bytes_used;
897 next_page = first_page+1;
899 /* All the rest of the pages should be free. We need to set their
900 * first_object_offset pointer to the start of the region, and
901 * set the bytes_used. */
903 gc_assert(page_table[next_page].allocated == FREE_PAGE_FLAG);
904 gc_assert(page_table[next_page].bytes_used == 0);
906 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
908 page_table[next_page].allocated = BOXED_PAGE_FLAG;
909 page_table[next_page].gen = gc_alloc_generation;
910 page_table[next_page].large_object = 1;
912 page_table[next_page].first_object_offset =
913 orig_first_page_bytes_used - PAGE_BYTES*(next_page-first_page);
915 /* Calculate the number of bytes used in this page. */
917 if ((bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt) > PAGE_BYTES) {
918 bytes_used = PAGE_BYTES;
921 page_table[next_page].bytes_used = bytes_used;
922 page_table[next_page].write_protected=0;
923 page_table[next_page].dont_move=0;
924 byte_cnt += bytes_used;
928 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
930 bytes_allocated += nbytes;
931 generations[gc_alloc_generation].bytes_allocated += nbytes;
933 /* Add the region to the new_areas if requested. */
935 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
937 /* Bump up last_free_page */
938 if (last_page+1 > last_free_page) {
939 last_free_page = last_page+1;
940 SetSymbolValue(ALLOCATION_POINTER,
941 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
943 release_spinlock(&free_pages_lock);
945 return((void *)(page_address(first_page)+orig_first_page_bytes_used));
949 gc_find_freeish_pages(long *restart_page_ptr, long nbytes, int unboxed)
954 long restart_page=*restart_page_ptr;
957 long large_p=(nbytes>=large_object_size);
958 gc_assert(free_pages_lock);
960 /* Search for a contiguous free space of at least nbytes. If it's
961 * a large object then align it on a page boundary by searching
962 * for a free page. */
965 first_page = restart_page;
967 while ((first_page < NUM_PAGES)
968 && (page_table[first_page].allocated != FREE_PAGE_FLAG))
971 while (first_page < NUM_PAGES) {
972 if(page_table[first_page].allocated == FREE_PAGE_FLAG)
974 if((page_table[first_page].allocated ==
975 (unboxed ? UNBOXED_PAGE_FLAG : BOXED_PAGE_FLAG)) &&
976 (page_table[first_page].large_object == 0) &&
977 (page_table[first_page].gen == gc_alloc_generation) &&
978 (page_table[first_page].bytes_used < (PAGE_BYTES-32)) &&
979 (page_table[first_page].write_protected == 0) &&
980 (page_table[first_page].dont_move == 0)) {
986 if (first_page >= NUM_PAGES) {
988 "Argh! gc_find_free_space failed (first_page), nbytes=%d.\n",
990 print_generation_stats(1);
994 gc_assert(page_table[first_page].write_protected == 0);
996 last_page = first_page;
997 bytes_found = PAGE_BYTES - page_table[first_page].bytes_used;
999 while (((bytes_found < nbytes)
1000 || (!large_p && (num_pages < 2)))
1001 && (last_page < (NUM_PAGES-1))
1002 && (page_table[last_page+1].allocated == FREE_PAGE_FLAG)) {
1005 bytes_found += PAGE_BYTES;
1006 gc_assert(page_table[last_page].write_protected == 0);
1009 region_size = (PAGE_BYTES - page_table[first_page].bytes_used)
1010 + PAGE_BYTES*(last_page-first_page);
1012 gc_assert(bytes_found == region_size);
1013 restart_page = last_page + 1;
1014 } while ((restart_page < NUM_PAGES) && (bytes_found < nbytes));
1016 /* Check for a failure */
1017 if ((restart_page >= NUM_PAGES) && (bytes_found < nbytes)) {
1019 "Argh! gc_find_freeish_pages failed (restart_page), nbytes=%d.\n",
1021 print_generation_stats(1);
1024 *restart_page_ptr=first_page;
1028 /* Allocate bytes. All the rest of the special-purpose allocation
1029 * functions will eventually call this */
1032 gc_alloc_with_region(long nbytes,int unboxed_p, struct alloc_region *my_region,
1035 void *new_free_pointer;
1037 if(nbytes>=large_object_size)
1038 return gc_alloc_large(nbytes,unboxed_p,my_region);
1040 /* Check whether there is room in the current alloc region. */
1041 new_free_pointer = my_region->free_pointer + nbytes;
1043 /* fprintf(stderr, "alloc %d bytes from %p to %p\n", nbytes,
1044 my_region->free_pointer, new_free_pointer); */
1046 if (new_free_pointer <= my_region->end_addr) {
1047 /* If so then allocate from the current alloc region. */
1048 void *new_obj = my_region->free_pointer;
1049 my_region->free_pointer = new_free_pointer;
1051 /* Unless a `quick' alloc was requested, check whether the
1052 alloc region is almost empty. */
1054 (my_region->end_addr - my_region->free_pointer) <= 32) {
1055 /* If so, finished with the current region. */
1056 gc_alloc_update_page_tables(unboxed_p, my_region);
1057 /* Set up a new region. */
1058 gc_alloc_new_region(32 /*bytes*/, unboxed_p, my_region);
1061 return((void *)new_obj);
1064 /* Else not enough free space in the current region: retry with a
1067 gc_alloc_update_page_tables(unboxed_p, my_region);
1068 gc_alloc_new_region(nbytes, unboxed_p, my_region);
1069 return gc_alloc_with_region(nbytes,unboxed_p,my_region,0);
1072 /* these are only used during GC: all allocation from the mutator calls
1073 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1077 gc_general_alloc(long nbytes,int unboxed_p,int quick_p)
1079 struct alloc_region *my_region =
1080 unboxed_p ? &unboxed_region : &boxed_region;
1081 return gc_alloc_with_region(nbytes,unboxed_p, my_region,quick_p);
1084 static inline void *
1085 gc_quick_alloc(long nbytes)
1087 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1090 static inline void *
1091 gc_quick_alloc_large(long nbytes)
1093 return gc_general_alloc(nbytes,ALLOC_BOXED,ALLOC_QUICK);
1096 static inline void *
1097 gc_alloc_unboxed(long nbytes)
1099 return gc_general_alloc(nbytes,ALLOC_UNBOXED,0);
1102 static inline void *
1103 gc_quick_alloc_unboxed(long nbytes)
1105 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1108 static inline void *
1109 gc_quick_alloc_large_unboxed(long nbytes)
1111 return gc_general_alloc(nbytes,ALLOC_UNBOXED,ALLOC_QUICK);
1115 * scavenging/transporting routines derived from gc.c in CMU CL ca. 18b
1118 extern long (*scavtab[256])(lispobj *where, lispobj object);
1119 extern lispobj (*transother[256])(lispobj object);
1120 extern long (*sizetab[256])(lispobj *where);
1122 /* Copy a large boxed object. If the object is in a large object
1123 * region then it is simply promoted, else it is copied. If it's large
1124 * enough then it's copied to a large object region.
1126 * Vectors may have shrunk. If the object is not copied the space
1127 * needs to be reclaimed, and the page_tables corrected. */
1129 copy_large_object(lispobj object, long nwords)
1135 gc_assert(is_lisp_pointer(object));
1136 gc_assert(from_space_p(object));
1137 gc_assert((nwords & 0x01) == 0);
1140 /* Check whether it's in a large object region. */
1141 first_page = find_page_index((void *)object);
1142 gc_assert(first_page >= 0);
1144 if (page_table[first_page].large_object) {
1146 /* Promote the object. */
1148 long remaining_bytes;
1151 long old_bytes_used;
1153 /* Note: Any page write-protection must be removed, else a
1154 * later scavenge_newspace may incorrectly not scavenge these
1155 * pages. This would not be necessary if they are added to the
1156 * new areas, but let's do it for them all (they'll probably
1157 * be written anyway?). */
1159 gc_assert(page_table[first_page].first_object_offset == 0);
1161 next_page = first_page;
1162 remaining_bytes = nwords*N_WORD_BYTES;
1163 while (remaining_bytes > PAGE_BYTES) {
1164 gc_assert(page_table[next_page].gen == from_space);
1165 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1166 gc_assert(page_table[next_page].large_object);
1167 gc_assert(page_table[next_page].first_object_offset==
1168 -PAGE_BYTES*(next_page-first_page));
1169 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1171 page_table[next_page].gen = new_space;
1173 /* Remove any write-protection. We should be able to rely
1174 * on the write-protect flag to avoid redundant calls. */
1175 if (page_table[next_page].write_protected) {
1176 os_protect(page_address(next_page), PAGE_BYTES, OS_VM_PROT_ALL);
1177 page_table[next_page].write_protected = 0;
1179 remaining_bytes -= PAGE_BYTES;
1183 /* Now only one page remains, but the object may have shrunk
1184 * so there may be more unused pages which will be freed. */
1186 /* The object may have shrunk but shouldn't have grown. */
1187 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1189 page_table[next_page].gen = new_space;
1190 gc_assert(page_table[next_page].allocated == BOXED_PAGE_FLAG);
1192 /* Adjust the bytes_used. */
1193 old_bytes_used = page_table[next_page].bytes_used;
1194 page_table[next_page].bytes_used = remaining_bytes;
1196 bytes_freed = old_bytes_used - remaining_bytes;
1198 /* Free any remaining pages; needs care. */
1200 while ((old_bytes_used == PAGE_BYTES) &&
1201 (page_table[next_page].gen == from_space) &&
1202 (page_table[next_page].allocated == BOXED_PAGE_FLAG) &&
1203 page_table[next_page].large_object &&
1204 (page_table[next_page].first_object_offset ==
1205 -(next_page - first_page)*PAGE_BYTES)) {
1206 /* Checks out OK, free the page. Don't need to bother zeroing
1207 * pages as this should have been done before shrinking the
1208 * object. These pages shouldn't be write-protected as they
1209 * should be zero filled. */
1210 gc_assert(page_table[next_page].write_protected == 0);
1212 old_bytes_used = page_table[next_page].bytes_used;
1213 page_table[next_page].allocated = FREE_PAGE_FLAG;
1214 page_table[next_page].bytes_used = 0;
1215 bytes_freed += old_bytes_used;
1219 generations[from_space].bytes_allocated -= N_WORD_BYTES*nwords +
1221 generations[new_space].bytes_allocated += N_WORD_BYTES*nwords;
1222 bytes_allocated -= bytes_freed;
1224 /* Add the region to the new_areas if requested. */
1225 add_new_area(first_page,0,nwords*N_WORD_BYTES);
1229 /* Get tag of object. */
1230 tag = lowtag_of(object);
1232 /* Allocate space. */
1233 new = gc_quick_alloc_large(nwords*N_WORD_BYTES);
1235 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1237 /* Return Lisp pointer of new object. */
1238 return ((lispobj) new) | tag;
1242 /* to copy unboxed objects */
1244 copy_unboxed_object(lispobj object, long nwords)
1249 gc_assert(is_lisp_pointer(object));
1250 gc_assert(from_space_p(object));
1251 gc_assert((nwords & 0x01) == 0);
1253 /* Get tag of object. */
1254 tag = lowtag_of(object);
1256 /* Allocate space. */
1257 new = gc_quick_alloc_unboxed(nwords*N_WORD_BYTES);
1259 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1261 /* Return Lisp pointer of new object. */
1262 return ((lispobj) new) | tag;
1265 /* to copy large unboxed objects
1267 * If the object is in a large object region then it is simply
1268 * promoted, else it is copied. If it's large enough then it's copied
1269 * to a large object region.
1271 * Bignums and vectors may have shrunk. If the object is not copied
1272 * the space needs to be reclaimed, and the page_tables corrected.
1274 * KLUDGE: There's a lot of cut-and-paste duplication between this
1275 * function and copy_large_object(..). -- WHN 20000619 */
1277 copy_large_unboxed_object(lispobj object, long nwords)
1283 gc_assert(is_lisp_pointer(object));
1284 gc_assert(from_space_p(object));
1285 gc_assert((nwords & 0x01) == 0);
1287 if ((nwords > 1024*1024) && gencgc_verbose)
1288 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n", nwords*N_WORD_BYTES));
1290 /* Check whether it's a large object. */
1291 first_page = find_page_index((void *)object);
1292 gc_assert(first_page >= 0);
1294 if (page_table[first_page].large_object) {
1295 /* Promote the object. Note: Unboxed objects may have been
1296 * allocated to a BOXED region so it may be necessary to
1297 * change the region to UNBOXED. */
1298 long remaining_bytes;
1301 long old_bytes_used;
1303 gc_assert(page_table[first_page].first_object_offset == 0);
1305 next_page = first_page;
1306 remaining_bytes = nwords*N_WORD_BYTES;
1307 while (remaining_bytes > PAGE_BYTES) {
1308 gc_assert(page_table[next_page].gen == from_space);
1309 gc_assert((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1310 || (page_table[next_page].allocated == BOXED_PAGE_FLAG));
1311 gc_assert(page_table[next_page].large_object);
1312 gc_assert(page_table[next_page].first_object_offset==
1313 -PAGE_BYTES*(next_page-first_page));
1314 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
1316 page_table[next_page].gen = new_space;
1317 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1318 remaining_bytes -= PAGE_BYTES;
1322 /* Now only one page remains, but the object may have shrunk so
1323 * there may be more unused pages which will be freed. */
1325 /* Object may have shrunk but shouldn't have grown - check. */
1326 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1328 page_table[next_page].gen = new_space;
1329 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1331 /* Adjust the bytes_used. */
1332 old_bytes_used = page_table[next_page].bytes_used;
1333 page_table[next_page].bytes_used = remaining_bytes;
1335 bytes_freed = old_bytes_used - remaining_bytes;
1337 /* Free any remaining pages; needs care. */
1339 while ((old_bytes_used == PAGE_BYTES) &&
1340 (page_table[next_page].gen == from_space) &&
1341 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
1342 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
1343 page_table[next_page].large_object &&
1344 (page_table[next_page].first_object_offset ==
1345 -(next_page - first_page)*PAGE_BYTES)) {
1346 /* Checks out OK, free the page. Don't need to both zeroing
1347 * pages as this should have been done before shrinking the
1348 * object. These pages shouldn't be write-protected, even if
1349 * boxed they should be zero filled. */
1350 gc_assert(page_table[next_page].write_protected == 0);
1352 old_bytes_used = page_table[next_page].bytes_used;
1353 page_table[next_page].allocated = FREE_PAGE_FLAG;
1354 page_table[next_page].bytes_used = 0;
1355 bytes_freed += old_bytes_used;
1359 if ((bytes_freed > 0) && gencgc_verbose)
1361 "/copy_large_unboxed bytes_freed=%d\n",
1364 generations[from_space].bytes_allocated -= nwords*N_WORD_BYTES + bytes_freed;
1365 generations[new_space].bytes_allocated += nwords*N_WORD_BYTES;
1366 bytes_allocated -= bytes_freed;
1371 /* Get tag of object. */
1372 tag = lowtag_of(object);
1374 /* Allocate space. */
1375 new = gc_quick_alloc_large_unboxed(nwords*N_WORD_BYTES);
1377 /* Copy the object. */
1378 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1380 /* Return Lisp pointer of new object. */
1381 return ((lispobj) new) | tag;
1390 * code and code-related objects
1393 static lispobj trans_fun_header(lispobj object);
1394 static lispobj trans_boxed(lispobj object);
1397 /* Scan a x86 compiled code object, looking for possible fixups that
1398 * have been missed after a move.
1400 * Two types of fixups are needed:
1401 * 1. Absolute fixups to within the code object.
1402 * 2. Relative fixups to outside the code object.
1404 * Currently only absolute fixups to the constant vector, or to the
1405 * code area are checked. */
1407 sniff_code_object(struct code *code, unsigned displacement)
1409 long nheader_words, ncode_words, nwords;
1411 void *constants_start_addr, *constants_end_addr;
1412 void *code_start_addr, *code_end_addr;
1413 int fixup_found = 0;
1415 if (!check_code_fixups)
1418 ncode_words = fixnum_value(code->code_size);
1419 nheader_words = HeaderValue(*(lispobj *)code);
1420 nwords = ncode_words + nheader_words;
1422 constants_start_addr = (void *)code + 5*N_WORD_BYTES;
1423 constants_end_addr = (void *)code + nheader_words*N_WORD_BYTES;
1424 code_start_addr = (void *)code + nheader_words*N_WORD_BYTES;
1425 code_end_addr = (void *)code + nwords*N_WORD_BYTES;
1427 /* Work through the unboxed code. */
1428 for (p = code_start_addr; p < code_end_addr; p++) {
1429 void *data = *(void **)p;
1430 unsigned d1 = *((unsigned char *)p - 1);
1431 unsigned d2 = *((unsigned char *)p - 2);
1432 unsigned d3 = *((unsigned char *)p - 3);
1433 unsigned d4 = *((unsigned char *)p - 4);
1435 unsigned d5 = *((unsigned char *)p - 5);
1436 unsigned d6 = *((unsigned char *)p - 6);
1439 /* Check for code references. */
1440 /* Check for a 32 bit word that looks like an absolute
1441 reference to within the code adea of the code object. */
1442 if ((data >= (code_start_addr-displacement))
1443 && (data < (code_end_addr-displacement))) {
1444 /* function header */
1446 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) == (unsigned)code)) {
1447 /* Skip the function header */
1451 /* the case of PUSH imm32 */
1455 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1456 p, d6, d5, d4, d3, d2, d1, data));
1457 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1459 /* the case of MOV [reg-8],imm32 */
1461 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1462 || d2==0x45 || d2==0x46 || d2==0x47)
1466 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1467 p, d6, d5, d4, d3, d2, d1, data));
1468 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1470 /* the case of LEA reg,[disp32] */
1471 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1474 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1475 p, d6, d5, d4, d3, d2, d1, data));
1476 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1480 /* Check for constant references. */
1481 /* Check for a 32 bit word that looks like an absolute
1482 reference to within the constant vector. Constant references
1484 if ((data >= (constants_start_addr-displacement))
1485 && (data < (constants_end_addr-displacement))
1486 && (((unsigned)data & 0x3) == 0)) {
1491 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1492 p, d6, d5, d4, d3, d2, d1, data));
1493 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1496 /* the case of MOV m32,EAX */
1500 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1501 p, d6, d5, d4, d3, d2, d1, data));
1502 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1505 /* the case of CMP m32,imm32 */
1506 if ((d1 == 0x3d) && (d2 == 0x81)) {
1509 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1510 p, d6, d5, d4, d3, d2, d1, data));
1512 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1515 /* Check for a mod=00, r/m=101 byte. */
1516 if ((d1 & 0xc7) == 5) {
1521 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1522 p, d6, d5, d4, d3, d2, d1, data));
1523 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1525 /* the case of CMP reg32,m32 */
1529 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1530 p, d6, d5, d4, d3, d2, d1, data));
1531 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1533 /* the case of MOV m32,reg32 */
1537 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1538 p, d6, d5, d4, d3, d2, d1, data));
1539 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1541 /* the case of MOV reg32,m32 */
1545 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1546 p, d6, d5, d4, d3, d2, d1, data));
1547 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1549 /* the case of LEA reg32,m32 */
1553 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1554 p, d6, d5, d4, d3, d2, d1, data));
1555 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1561 /* If anything was found, print some information on the code
1565 "/compiled code object at %x: header words = %d, code words = %d\n",
1566 code, nheader_words, ncode_words));
1568 "/const start = %x, end = %x\n",
1569 constants_start_addr, constants_end_addr));
1571 "/code start = %x, end = %x\n",
1572 code_start_addr, code_end_addr));
1577 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1579 long nheader_words, ncode_words, nwords;
1580 void *constants_start_addr, *constants_end_addr;
1581 void *code_start_addr, *code_end_addr;
1582 lispobj fixups = NIL;
1583 unsigned displacement = (unsigned)new_code - (unsigned)old_code;
1584 struct vector *fixups_vector;
1586 ncode_words = fixnum_value(new_code->code_size);
1587 nheader_words = HeaderValue(*(lispobj *)new_code);
1588 nwords = ncode_words + nheader_words;
1590 "/compiled code object at %x: header words = %d, code words = %d\n",
1591 new_code, nheader_words, ncode_words)); */
1592 constants_start_addr = (void *)new_code + 5*N_WORD_BYTES;
1593 constants_end_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1594 code_start_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1595 code_end_addr = (void *)new_code + nwords*N_WORD_BYTES;
1598 "/const start = %x, end = %x\n",
1599 constants_start_addr,constants_end_addr));
1601 "/code start = %x; end = %x\n",
1602 code_start_addr,code_end_addr));
1605 /* The first constant should be a pointer to the fixups for this
1606 code objects. Check. */
1607 fixups = new_code->constants[0];
1609 /* It will be 0 or the unbound-marker if there are no fixups (as
1610 * will be the case if the code object has been purified, for
1611 * example) and will be an other pointer if it is valid. */
1612 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1613 !is_lisp_pointer(fixups)) {
1614 /* Check for possible errors. */
1615 if (check_code_fixups)
1616 sniff_code_object(new_code, displacement);
1621 fixups_vector = (struct vector *)native_pointer(fixups);
1623 /* Could be pointing to a forwarding pointer. */
1624 /* FIXME is this always in from_space? if so, could replace this code with
1625 * forwarding_pointer_p/forwarding_pointer_value */
1626 if (is_lisp_pointer(fixups) &&
1627 (find_page_index((void*)fixups_vector) != -1) &&
1628 (fixups_vector->header == 0x01)) {
1629 /* If so, then follow it. */
1630 /*SHOW("following pointer to a forwarding pointer");*/
1631 fixups_vector = (struct vector *)native_pointer((lispobj)fixups_vector->length);
1634 /*SHOW("got fixups");*/
1636 if (widetag_of(fixups_vector->header) == SIMPLE_ARRAY_WORD_WIDETAG) {
1637 /* Got the fixups for the code block. Now work through the vector,
1638 and apply a fixup at each address. */
1639 long length = fixnum_value(fixups_vector->length);
1641 for (i = 0; i < length; i++) {
1642 unsigned offset = fixups_vector->data[i];
1643 /* Now check the current value of offset. */
1644 unsigned old_value =
1645 *(unsigned *)((unsigned)code_start_addr + offset);
1647 /* If it's within the old_code object then it must be an
1648 * absolute fixup (relative ones are not saved) */
1649 if ((old_value >= (unsigned)old_code)
1650 && (old_value < ((unsigned)old_code + nwords*N_WORD_BYTES)))
1651 /* So add the dispacement. */
1652 *(unsigned *)((unsigned)code_start_addr + offset) =
1653 old_value + displacement;
1655 /* It is outside the old code object so it must be a
1656 * relative fixup (absolute fixups are not saved). So
1657 * subtract the displacement. */
1658 *(unsigned *)((unsigned)code_start_addr + offset) =
1659 old_value - displacement;
1662 fprintf(stderr, "widetag of fixup vector is %d\n", widetag_of(fixups_vector->header));
1665 /* Check for possible errors. */
1666 if (check_code_fixups) {
1667 sniff_code_object(new_code,displacement);
1673 trans_boxed_large(lispobj object)
1676 unsigned long length;
1678 gc_assert(is_lisp_pointer(object));
1680 header = *((lispobj *) native_pointer(object));
1681 length = HeaderValue(header) + 1;
1682 length = CEILING(length, 2);
1684 return copy_large_object(object, length);
1689 trans_unboxed_large(lispobj object)
1692 unsigned long length;
1695 gc_assert(is_lisp_pointer(object));
1697 header = *((lispobj *) native_pointer(object));
1698 length = HeaderValue(header) + 1;
1699 length = CEILING(length, 2);
1701 return copy_large_unboxed_object(object, length);
1706 * vector-like objects
1710 /* FIXME: What does this mean? */
1711 int gencgc_hash = 1;
1714 scav_vector(lispobj *where, lispobj object)
1716 unsigned long kv_length;
1718 unsigned long length = 0; /* (0 = dummy to stop GCC warning) */
1719 lispobj *hash_table;
1720 lispobj empty_symbol;
1721 unsigned long *index_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1722 unsigned long *next_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1723 unsigned long *hash_vector = NULL; /* (NULL = dummy to stop GCC warning) */
1725 unsigned next_vector_length = 0;
1727 /* FIXME: A comment explaining this would be nice. It looks as
1728 * though SB-VM:VECTOR-VALID-HASHING-SUBTYPE is set for EQ-based
1729 * hash tables in the Lisp HASH-TABLE code, and nowhere else. */
1730 if (HeaderValue(object) != subtype_VectorValidHashing)
1734 /* This is set for backward compatibility. FIXME: Do we need
1737 (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
1741 kv_length = fixnum_value(where[1]);
1742 kv_vector = where + 2; /* Skip the header and length. */
1743 /*FSHOW((stderr,"/kv_length = %d\n", kv_length));*/
1745 /* Scavenge element 0, which may be a hash-table structure. */
1746 scavenge(where+2, 1);
1747 if (!is_lisp_pointer(where[2])) {
1748 lose("no pointer at %x in hash table", where[2]);
1750 hash_table = (lispobj *)native_pointer(where[2]);
1751 /*FSHOW((stderr,"/hash_table = %x\n", hash_table));*/
1752 if (widetag_of(hash_table[0]) != INSTANCE_HEADER_WIDETAG) {
1753 lose("hash table not instance (%x at %x)", hash_table[0], hash_table);
1756 /* Scavenge element 1, which should be some internal symbol that
1757 * the hash table code reserves for marking empty slots. */
1758 scavenge(where+3, 1);
1759 if (!is_lisp_pointer(where[3])) {
1760 lose("not empty-hash-table-slot symbol pointer: %x", where[3]);
1762 empty_symbol = where[3];
1763 /* fprintf(stderr,"* empty_symbol = %x\n", empty_symbol);*/
1764 if (widetag_of(*(lispobj *)native_pointer(empty_symbol)) !=
1765 SYMBOL_HEADER_WIDETAG) {
1766 lose("not a symbol where empty-hash-table-slot symbol expected: %x",
1767 *(lispobj *)native_pointer(empty_symbol));
1770 /* Scavenge hash table, which will fix the positions of the other
1771 * needed objects. */
1772 scavenge(hash_table, 16);
1774 /* Cross-check the kv_vector. */
1775 if (where != (lispobj *)native_pointer(hash_table[9])) {
1776 lose("hash_table table!=this table %x", hash_table[9]);
1780 weak_p_obj = hash_table[10];
1784 lispobj index_vector_obj = hash_table[13];
1786 if (is_lisp_pointer(index_vector_obj) &&
1787 (widetag_of(*(lispobj *)native_pointer(index_vector_obj)) ==
1788 SIMPLE_ARRAY_WORD_WIDETAG)) {
1789 index_vector = ((lispobj *)native_pointer(index_vector_obj)) + 2;
1790 /*FSHOW((stderr, "/index_vector = %x\n",index_vector));*/
1791 length = fixnum_value(((lispobj *)native_pointer(index_vector_obj))[1]);
1792 /*FSHOW((stderr, "/length = %d\n", length));*/
1794 lose("invalid index_vector %x", index_vector_obj);
1800 lispobj next_vector_obj = hash_table[14];
1802 if (is_lisp_pointer(next_vector_obj) &&
1803 (widetag_of(*(lispobj *)native_pointer(next_vector_obj)) ==
1804 SIMPLE_ARRAY_WORD_WIDETAG)) {
1805 next_vector = ((lispobj *)native_pointer(next_vector_obj)) + 2;
1806 /*FSHOW((stderr, "/next_vector = %x\n", next_vector));*/
1807 next_vector_length = fixnum_value(((lispobj *)native_pointer(next_vector_obj))[1]);
1808 /*FSHOW((stderr, "/next_vector_length = %d\n", next_vector_length));*/
1810 lose("invalid next_vector %x", next_vector_obj);
1814 /* maybe hash vector */
1816 /* FIXME: This bare "15" offset should become a symbolic
1817 * expression of some sort. And all the other bare offsets
1818 * too. And the bare "16" in scavenge(hash_table, 16). And
1819 * probably other stuff too. Ugh.. */
1820 lispobj hash_vector_obj = hash_table[15];
1822 if (is_lisp_pointer(hash_vector_obj) &&
1823 (widetag_of(*(lispobj *)native_pointer(hash_vector_obj)) ==
1824 SIMPLE_ARRAY_WORD_WIDETAG)){
1825 hash_vector = ((lispobj *)native_pointer(hash_vector_obj)) + 2;
1826 /*FSHOW((stderr, "/hash_vector = %x\n", hash_vector));*/
1827 gc_assert(fixnum_value(((lispobj *)native_pointer(hash_vector_obj))[1])
1828 == next_vector_length);
1831 /*FSHOW((stderr, "/no hash_vector: %x\n", hash_vector_obj));*/
1835 /* These lengths could be different as the index_vector can be a
1836 * different length from the others, a larger index_vector could help
1837 * reduce collisions. */
1838 gc_assert(next_vector_length*2 == kv_length);
1840 /* now all set up.. */
1842 /* Work through the KV vector. */
1845 for (i = 1; i < next_vector_length; i++) {
1846 lispobj old_key = kv_vector[2*i];
1848 #if N_WORD_BITS == 32
1849 unsigned long old_index = (old_key & 0x1fffffff)%length;
1850 #elif N_WORD_BITS == 64
1851 unsigned long old_index = (old_key & 0x1fffffffffffffff)%length;
1854 /* Scavenge the key and value. */
1855 scavenge(&kv_vector[2*i],2);
1857 /* Check whether the key has moved and is EQ based. */
1859 lispobj new_key = kv_vector[2*i];
1860 #if N_WORD_BITS == 32
1861 unsigned long new_index = (new_key & 0x1fffffff)%length;
1862 #elif N_WORD_BITS == 64
1863 unsigned long new_index = (new_key & 0x1fffffffffffffff)%length;
1866 if ((old_index != new_index) &&
1867 ((!hash_vector) || (hash_vector[i] == 0x80000000)) &&
1868 ((new_key != empty_symbol) ||
1869 (kv_vector[2*i] != empty_symbol))) {
1872 "* EQ key %d moved from %x to %x; index %d to %d\n",
1873 i, old_key, new_key, old_index, new_index));*/
1875 if (index_vector[old_index] != 0) {
1876 /*FSHOW((stderr, "/P1 %d\n", index_vector[old_index]));*/
1878 /* Unlink the key from the old_index chain. */
1879 if (index_vector[old_index] == i) {
1880 /*FSHOW((stderr, "/P2a %d\n", next_vector[i]));*/
1881 index_vector[old_index] = next_vector[i];
1882 /* Link it into the needing rehash chain. */
1883 next_vector[i] = fixnum_value(hash_table[11]);
1884 hash_table[11] = make_fixnum(i);
1887 unsigned prior = index_vector[old_index];
1888 unsigned next = next_vector[prior];
1890 /*FSHOW((stderr, "/P3a %d %d\n", prior, next));*/
1893 /*FSHOW((stderr, "/P3b %d %d\n", prior, next));*/
1896 next_vector[prior] = next_vector[next];
1897 /* Link it into the needing rehash
1900 fixnum_value(hash_table[11]);
1901 hash_table[11] = make_fixnum(next);
1906 next = next_vector[next];
1914 return (CEILING(kv_length + 2, 2));
1923 /* XX This is a hack adapted from cgc.c. These don't work too
1924 * efficiently with the gencgc as a list of the weak pointers is
1925 * maintained within the objects which causes writes to the pages. A
1926 * limited attempt is made to avoid unnecessary writes, but this needs
1928 #define WEAK_POINTER_NWORDS \
1929 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1932 scav_weak_pointer(lispobj *where, lispobj object)
1934 struct weak_pointer *wp = weak_pointers;
1935 /* Push the weak pointer onto the list of weak pointers.
1936 * Do I have to watch for duplicates? Originally this was
1937 * part of trans_weak_pointer but that didn't work in the
1938 * case where the WP was in a promoted region.
1941 /* Check whether it's already in the list. */
1942 while (wp != NULL) {
1943 if (wp == (struct weak_pointer*)where) {
1949 /* Add it to the start of the list. */
1950 wp = (struct weak_pointer*)where;
1951 if (wp->next != weak_pointers) {
1952 wp->next = weak_pointers;
1954 /*SHOW("avoided write to weak pointer");*/
1959 /* Do not let GC scavenge the value slot of the weak pointer.
1960 * (That is why it is a weak pointer.) */
1962 return WEAK_POINTER_NWORDS;
1967 search_read_only_space(void *pointer)
1969 lispobj *start = (lispobj *) READ_ONLY_SPACE_START;
1970 lispobj *end = (lispobj *) SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1971 if ((pointer < (void *)start) || (pointer >= (void *)end))
1973 return (search_space(start,
1974 (((lispobj *)pointer)+2)-start,
1975 (lispobj *) pointer));
1979 search_static_space(void *pointer)
1981 lispobj *start = (lispobj *)STATIC_SPACE_START;
1982 lispobj *end = (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1983 if ((pointer < (void *)start) || (pointer >= (void *)end))
1985 return (search_space(start,
1986 (((lispobj *)pointer)+2)-start,
1987 (lispobj *) pointer));
1990 /* a faster version for searching the dynamic space. This will work even
1991 * if the object is in a current allocation region. */
1993 search_dynamic_space(void *pointer)
1995 long page_index = find_page_index(pointer);
1998 /* The address may be invalid, so do some checks. */
1999 if ((page_index == -1) ||
2000 (page_table[page_index].allocated == FREE_PAGE_FLAG))
2002 start = (lispobj *)((void *)page_address(page_index)
2003 + page_table[page_index].first_object_offset);
2004 return (search_space(start,
2005 (((lispobj *)pointer)+2)-start,
2006 (lispobj *)pointer));
2009 /* Is there any possibility that pointer is a valid Lisp object
2010 * reference, and/or something else (e.g. subroutine call return
2011 * address) which should prevent us from moving the referred-to thing?
2012 * This is called from preserve_pointers() */
2014 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2016 lispobj *start_addr;
2018 /* Find the object start address. */
2019 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2023 /* We need to allow raw pointers into Code objects for return
2024 * addresses. This will also pick up pointers to functions in code
2026 if (widetag_of(*start_addr) == CODE_HEADER_WIDETAG) {
2027 /* XXX could do some further checks here */
2031 /* If it's not a return address then it needs to be a valid Lisp
2033 if (!is_lisp_pointer((lispobj)pointer)) {
2037 /* Check that the object pointed to is consistent with the pointer
2040 switch (lowtag_of((lispobj)pointer)) {
2041 case FUN_POINTER_LOWTAG:
2042 /* Start_addr should be the enclosing code object, or a closure
2044 switch (widetag_of(*start_addr)) {
2045 case CODE_HEADER_WIDETAG:
2046 /* This case is probably caught above. */
2048 case CLOSURE_HEADER_WIDETAG:
2049 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2050 if ((unsigned)pointer !=
2051 ((unsigned)start_addr+FUN_POINTER_LOWTAG)) {
2055 pointer, start_addr, *start_addr));
2063 pointer, start_addr, *start_addr));
2067 case LIST_POINTER_LOWTAG:
2068 if ((unsigned)pointer !=
2069 ((unsigned)start_addr+LIST_POINTER_LOWTAG)) {
2073 pointer, start_addr, *start_addr));
2076 /* Is it plausible cons? */
2077 if ((is_lisp_pointer(start_addr[0])
2078 || (fixnump(start_addr[0]))
2079 || (widetag_of(start_addr[0]) == CHARACTER_WIDETAG)
2080 || (widetag_of(start_addr[0]) == UNBOUND_MARKER_WIDETAG))
2081 && (is_lisp_pointer(start_addr[1])
2082 || (fixnump(start_addr[1]))
2083 || (widetag_of(start_addr[1]) == CHARACTER_WIDETAG)
2084 || (widetag_of(start_addr[1]) == UNBOUND_MARKER_WIDETAG)))
2090 pointer, start_addr, *start_addr));
2093 case INSTANCE_POINTER_LOWTAG:
2094 if ((unsigned)pointer !=
2095 ((unsigned)start_addr+INSTANCE_POINTER_LOWTAG)) {
2099 pointer, start_addr, *start_addr));
2102 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2106 pointer, start_addr, *start_addr));
2110 case OTHER_POINTER_LOWTAG:
2111 if ((unsigned)pointer !=
2112 ((int)start_addr+OTHER_POINTER_LOWTAG)) {
2116 pointer, start_addr, *start_addr));
2119 /* Is it plausible? Not a cons. XXX should check the headers. */
2120 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2124 pointer, start_addr, *start_addr));
2127 switch (widetag_of(start_addr[0])) {
2128 case UNBOUND_MARKER_WIDETAG:
2129 case CHARACTER_WIDETAG:
2133 pointer, start_addr, *start_addr));
2136 /* only pointed to by function pointers? */
2137 case CLOSURE_HEADER_WIDETAG:
2138 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2142 pointer, start_addr, *start_addr));
2145 case INSTANCE_HEADER_WIDETAG:
2149 pointer, start_addr, *start_addr));
2152 /* the valid other immediate pointer objects */
2153 case SIMPLE_VECTOR_WIDETAG:
2155 case COMPLEX_WIDETAG:
2156 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2157 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2159 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2160 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2162 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2163 case COMPLEX_LONG_FLOAT_WIDETAG:
2165 case SIMPLE_ARRAY_WIDETAG:
2166 case COMPLEX_BASE_STRING_WIDETAG:
2167 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
2168 case COMPLEX_CHARACTER_STRING_WIDETAG:
2170 case COMPLEX_VECTOR_NIL_WIDETAG:
2171 case COMPLEX_BIT_VECTOR_WIDETAG:
2172 case COMPLEX_VECTOR_WIDETAG:
2173 case COMPLEX_ARRAY_WIDETAG:
2174 case VALUE_CELL_HEADER_WIDETAG:
2175 case SYMBOL_HEADER_WIDETAG:
2177 case CODE_HEADER_WIDETAG:
2178 case BIGNUM_WIDETAG:
2179 case SINGLE_FLOAT_WIDETAG:
2180 case DOUBLE_FLOAT_WIDETAG:
2181 #ifdef LONG_FLOAT_WIDETAG
2182 case LONG_FLOAT_WIDETAG:
2184 case SIMPLE_BASE_STRING_WIDETAG:
2185 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2186 case SIMPLE_CHARACTER_STRING_WIDETAG:
2188 case SIMPLE_BIT_VECTOR_WIDETAG:
2189 case SIMPLE_ARRAY_NIL_WIDETAG:
2190 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2191 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2192 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2193 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2194 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2195 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2196 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2197 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2199 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2200 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2201 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2202 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2204 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2205 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2207 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2208 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2210 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2211 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2213 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2214 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2216 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2217 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2219 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2220 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2222 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2223 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
2225 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2226 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2228 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2229 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2230 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2231 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2233 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2234 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2236 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2237 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2239 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2240 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2243 case WEAK_POINTER_WIDETAG:
2250 pointer, start_addr, *start_addr));
2258 pointer, start_addr, *start_addr));
2266 /* Adjust large bignum and vector objects. This will adjust the
2267 * allocated region if the size has shrunk, and move unboxed objects
2268 * into unboxed pages. The pages are not promoted here, and the
2269 * promoted region is not added to the new_regions; this is really
2270 * only designed to be called from preserve_pointer(). Shouldn't fail
2271 * if this is missed, just may delay the moving of objects to unboxed
2272 * pages, and the freeing of pages. */
2274 maybe_adjust_large_object(lispobj *where)
2279 long remaining_bytes;
2282 long old_bytes_used;
2286 /* Check whether it's a vector or bignum object. */
2287 switch (widetag_of(where[0])) {
2288 case SIMPLE_VECTOR_WIDETAG:
2289 boxed = BOXED_PAGE_FLAG;
2291 case BIGNUM_WIDETAG:
2292 case SIMPLE_BASE_STRING_WIDETAG:
2293 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2294 case SIMPLE_CHARACTER_STRING_WIDETAG:
2296 case SIMPLE_BIT_VECTOR_WIDETAG:
2297 case SIMPLE_ARRAY_NIL_WIDETAG:
2298 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2299 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2300 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2301 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2302 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2303 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2304 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2305 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2307 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2308 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2309 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2310 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2312 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2313 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2315 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2316 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2318 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2319 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2321 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2322 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2324 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2325 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2327 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2328 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2330 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2331 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
2333 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2334 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2336 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2337 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2338 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2339 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2341 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2342 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2344 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2345 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2347 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2348 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2350 boxed = UNBOXED_PAGE_FLAG;
2356 /* Find its current size. */
2357 nwords = (sizetab[widetag_of(where[0])])(where);
2359 first_page = find_page_index((void *)where);
2360 gc_assert(first_page >= 0);
2362 /* Note: Any page write-protection must be removed, else a later
2363 * scavenge_newspace may incorrectly not scavenge these pages.
2364 * This would not be necessary if they are added to the new areas,
2365 * but lets do it for them all (they'll probably be written
2368 gc_assert(page_table[first_page].first_object_offset == 0);
2370 next_page = first_page;
2371 remaining_bytes = nwords*N_WORD_BYTES;
2372 while (remaining_bytes > PAGE_BYTES) {
2373 gc_assert(page_table[next_page].gen == from_space);
2374 gc_assert((page_table[next_page].allocated == BOXED_PAGE_FLAG)
2375 || (page_table[next_page].allocated == UNBOXED_PAGE_FLAG));
2376 gc_assert(page_table[next_page].large_object);
2377 gc_assert(page_table[next_page].first_object_offset ==
2378 -PAGE_BYTES*(next_page-first_page));
2379 gc_assert(page_table[next_page].bytes_used == PAGE_BYTES);
2381 page_table[next_page].allocated = boxed;
2383 /* Shouldn't be write-protected at this stage. Essential that the
2385 gc_assert(!page_table[next_page].write_protected);
2386 remaining_bytes -= PAGE_BYTES;
2390 /* Now only one page remains, but the object may have shrunk so
2391 * there may be more unused pages which will be freed. */
2393 /* Object may have shrunk but shouldn't have grown - check. */
2394 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2396 page_table[next_page].allocated = boxed;
2397 gc_assert(page_table[next_page].allocated ==
2398 page_table[first_page].allocated);
2400 /* Adjust the bytes_used. */
2401 old_bytes_used = page_table[next_page].bytes_used;
2402 page_table[next_page].bytes_used = remaining_bytes;
2404 bytes_freed = old_bytes_used - remaining_bytes;
2406 /* Free any remaining pages; needs care. */
2408 while ((old_bytes_used == PAGE_BYTES) &&
2409 (page_table[next_page].gen == from_space) &&
2410 ((page_table[next_page].allocated == UNBOXED_PAGE_FLAG)
2411 || (page_table[next_page].allocated == BOXED_PAGE_FLAG)) &&
2412 page_table[next_page].large_object &&
2413 (page_table[next_page].first_object_offset ==
2414 -(next_page - first_page)*PAGE_BYTES)) {
2415 /* It checks out OK, free the page. We don't need to both zeroing
2416 * pages as this should have been done before shrinking the
2417 * object. These pages shouldn't be write protected as they
2418 * should be zero filled. */
2419 gc_assert(page_table[next_page].write_protected == 0);
2421 old_bytes_used = page_table[next_page].bytes_used;
2422 page_table[next_page].allocated = FREE_PAGE_FLAG;
2423 page_table[next_page].bytes_used = 0;
2424 bytes_freed += old_bytes_used;
2428 if ((bytes_freed > 0) && gencgc_verbose) {
2430 "/maybe_adjust_large_object() freed %d\n",
2434 generations[from_space].bytes_allocated -= bytes_freed;
2435 bytes_allocated -= bytes_freed;
2440 /* Take a possible pointer to a Lisp object and mark its page in the
2441 * page_table so that it will not be relocated during a GC.
2443 * This involves locating the page it points to, then backing up to
2444 * the start of its region, then marking all pages dont_move from there
2445 * up to the first page that's not full or has a different generation
2447 * It is assumed that all the page static flags have been cleared at
2448 * the start of a GC.
2450 * It is also assumed that the current gc_alloc() region has been
2451 * flushed and the tables updated. */
2453 preserve_pointer(void *addr)
2455 long addr_page_index = find_page_index(addr);
2458 unsigned region_allocation;
2460 /* quick check 1: Address is quite likely to have been invalid. */
2461 if ((addr_page_index == -1)
2462 || (page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2463 || (page_table[addr_page_index].bytes_used == 0)
2464 || (page_table[addr_page_index].gen != from_space)
2465 /* Skip if already marked dont_move. */
2466 || (page_table[addr_page_index].dont_move != 0))
2468 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2469 /* (Now that we know that addr_page_index is in range, it's
2470 * safe to index into page_table[] with it.) */
2471 region_allocation = page_table[addr_page_index].allocated;
2473 /* quick check 2: Check the offset within the page.
2476 if (((unsigned)addr & (PAGE_BYTES - 1)) > page_table[addr_page_index].bytes_used)
2479 /* Filter out anything which can't be a pointer to a Lisp object
2480 * (or, as a special case which also requires dont_move, a return
2481 * address referring to something in a CodeObject). This is
2482 * expensive but important, since it vastly reduces the
2483 * probability that random garbage will be bogusly interpreted as
2484 * a pointer which prevents a page from moving. */
2485 if (!(possibly_valid_dynamic_space_pointer(addr)))
2488 /* Find the beginning of the region. Note that there may be
2489 * objects in the region preceding the one that we were passed a
2490 * pointer to: if this is the case, we will write-protect all the
2491 * previous objects' pages too. */
2494 /* I think this'd work just as well, but without the assertions.
2495 * -dan 2004.01.01 */
2497 find_page_index(page_address(addr_page_index)+
2498 page_table[addr_page_index].first_object_offset);
2500 first_page = addr_page_index;
2501 while (page_table[first_page].first_object_offset != 0) {
2503 /* Do some checks. */
2504 gc_assert(page_table[first_page].bytes_used == PAGE_BYTES);
2505 gc_assert(page_table[first_page].gen == from_space);
2506 gc_assert(page_table[first_page].allocated == region_allocation);
2510 /* Adjust any large objects before promotion as they won't be
2511 * copied after promotion. */
2512 if (page_table[first_page].large_object) {
2513 maybe_adjust_large_object(page_address(first_page));
2514 /* If a large object has shrunk then addr may now point to a
2515 * free area in which case it's ignored here. Note it gets
2516 * through the valid pointer test above because the tail looks
2518 if ((page_table[addr_page_index].allocated == FREE_PAGE_FLAG)
2519 || (page_table[addr_page_index].bytes_used == 0)
2520 /* Check the offset within the page. */
2521 || (((unsigned)addr & (PAGE_BYTES - 1))
2522 > page_table[addr_page_index].bytes_used)) {
2524 "weird? ignore ptr 0x%x to freed area of large object\n",
2528 /* It may have moved to unboxed pages. */
2529 region_allocation = page_table[first_page].allocated;
2532 /* Now work forward until the end of this contiguous area is found,
2533 * marking all pages as dont_move. */
2534 for (i = first_page; ;i++) {
2535 gc_assert(page_table[i].allocated == region_allocation);
2537 /* Mark the page static. */
2538 page_table[i].dont_move = 1;
2540 /* Move the page to the new_space. XX I'd rather not do this
2541 * but the GC logic is not quite able to copy with the static
2542 * pages remaining in the from space. This also requires the
2543 * generation bytes_allocated counters be updated. */
2544 page_table[i].gen = new_space;
2545 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2546 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2548 /* It is essential that the pages are not write protected as
2549 * they may have pointers into the old-space which need
2550 * scavenging. They shouldn't be write protected at this
2552 gc_assert(!page_table[i].write_protected);
2554 /* Check whether this is the last page in this contiguous block.. */
2555 if ((page_table[i].bytes_used < PAGE_BYTES)
2556 /* ..or it is PAGE_BYTES and is the last in the block */
2557 || (page_table[i+1].allocated == FREE_PAGE_FLAG)
2558 || (page_table[i+1].bytes_used == 0) /* next page free */
2559 || (page_table[i+1].gen != from_space) /* diff. gen */
2560 || (page_table[i+1].first_object_offset == 0))
2564 /* Check that the page is now static. */
2565 gc_assert(page_table[addr_page_index].dont_move != 0);
2568 /* If the given page is not write-protected, then scan it for pointers
2569 * to younger generations or the top temp. generation, if no
2570 * suspicious pointers are found then the page is write-protected.
2572 * Care is taken to check for pointers to the current gc_alloc()
2573 * region if it is a younger generation or the temp. generation. This
2574 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2575 * the gc_alloc_generation does not need to be checked as this is only
2576 * called from scavenge_generation() when the gc_alloc generation is
2577 * younger, so it just checks if there is a pointer to the current
2580 * We return 1 if the page was write-protected, else 0. */
2582 update_page_write_prot(long page)
2584 int gen = page_table[page].gen;
2587 void **page_addr = (void **)page_address(page);
2588 long num_words = page_table[page].bytes_used / N_WORD_BYTES;
2590 /* Shouldn't be a free page. */
2591 gc_assert(page_table[page].allocated != FREE_PAGE_FLAG);
2592 gc_assert(page_table[page].bytes_used != 0);
2594 /* Skip if it's already write-protected, pinned, or unboxed */
2595 if (page_table[page].write_protected
2596 || page_table[page].dont_move
2597 || (page_table[page].allocated & UNBOXED_PAGE_FLAG))
2600 /* Scan the page for pointers to younger generations or the
2601 * top temp. generation. */
2603 for (j = 0; j < num_words; j++) {
2604 void *ptr = *(page_addr+j);
2605 long index = find_page_index(ptr);
2607 /* Check that it's in the dynamic space */
2609 if (/* Does it point to a younger or the temp. generation? */
2610 ((page_table[index].allocated != FREE_PAGE_FLAG)
2611 && (page_table[index].bytes_used != 0)
2612 && ((page_table[index].gen < gen)
2613 || (page_table[index].gen == NUM_GENERATIONS)))
2615 /* Or does it point within a current gc_alloc() region? */
2616 || ((boxed_region.start_addr <= ptr)
2617 && (ptr <= boxed_region.free_pointer))
2618 || ((unboxed_region.start_addr <= ptr)
2619 && (ptr <= unboxed_region.free_pointer))) {
2626 /* Write-protect the page. */
2627 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2629 os_protect((void *)page_addr,
2631 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2633 /* Note the page as protected in the page tables. */
2634 page_table[page].write_protected = 1;
2640 /* Scavenge a generation.
2642 * This will not resolve all pointers when generation is the new
2643 * space, as new objects may be added which are not checked here - use
2644 * scavenge_newspace generation.
2646 * Write-protected pages should not have any pointers to the
2647 * from_space so do need scavenging; thus write-protected pages are
2648 * not always scavenged. There is some code to check that these pages
2649 * are not written; but to check fully the write-protected pages need
2650 * to be scavenged by disabling the code to skip them.
2652 * Under the current scheme when a generation is GCed the younger
2653 * generations will be empty. So, when a generation is being GCed it
2654 * is only necessary to scavenge the older generations for pointers
2655 * not the younger. So a page that does not have pointers to younger
2656 * generations does not need to be scavenged.
2658 * The write-protection can be used to note pages that don't have
2659 * pointers to younger pages. But pages can be written without having
2660 * pointers to younger generations. After the pages are scavenged here
2661 * they can be scanned for pointers to younger generations and if
2662 * there are none the page can be write-protected.
2664 * One complication is when the newspace is the top temp. generation.
2666 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2667 * that none were written, which they shouldn't be as they should have
2668 * no pointers to younger generations. This breaks down for weak
2669 * pointers as the objects contain a link to the next and are written
2670 * if a weak pointer is scavenged. Still it's a useful check. */
2672 scavenge_generation(int generation)
2679 /* Clear the write_protected_cleared flags on all pages. */
2680 for (i = 0; i < NUM_PAGES; i++)
2681 page_table[i].write_protected_cleared = 0;
2684 for (i = 0; i < last_free_page; i++) {
2685 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2686 && (page_table[i].bytes_used != 0)
2687 && (page_table[i].gen == generation)) {
2689 int write_protected=1;
2691 /* This should be the start of a region */
2692 gc_assert(page_table[i].first_object_offset == 0);
2694 /* Now work forward until the end of the region */
2695 for (last_page = i; ; last_page++) {
2697 write_protected && page_table[last_page].write_protected;
2698 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2699 /* Or it is PAGE_BYTES and is the last in the block */
2700 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2701 || (page_table[last_page+1].bytes_used == 0)
2702 || (page_table[last_page+1].gen != generation)
2703 || (page_table[last_page+1].first_object_offset == 0))
2706 if (!write_protected) {
2707 scavenge(page_address(i),
2708 (page_table[last_page].bytes_used +
2709 (last_page-i)*PAGE_BYTES)/N_WORD_BYTES);
2711 /* Now scan the pages and write protect those that
2712 * don't have pointers to younger generations. */
2713 if (enable_page_protection) {
2714 for (j = i; j <= last_page; j++) {
2715 num_wp += update_page_write_prot(j);
2722 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2724 "/write protected %d pages within generation %d\n",
2725 num_wp, generation));
2729 /* Check that none of the write_protected pages in this generation
2730 * have been written to. */
2731 for (i = 0; i < NUM_PAGES; i++) {
2732 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2733 && (page_table[i].bytes_used != 0)
2734 && (page_table[i].gen == generation)
2735 && (page_table[i].write_protected_cleared != 0)) {
2736 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2738 "/page bytes_used=%d first_object_offset=%d dont_move=%d\n",
2739 page_table[i].bytes_used,
2740 page_table[i].first_object_offset,
2741 page_table[i].dont_move));
2742 lose("write to protected page %d in scavenge_generation()", i);
2749 /* Scavenge a newspace generation. As it is scavenged new objects may
2750 * be allocated to it; these will also need to be scavenged. This
2751 * repeats until there are no more objects unscavenged in the
2752 * newspace generation.
2754 * To help improve the efficiency, areas written are recorded by
2755 * gc_alloc() and only these scavenged. Sometimes a little more will be
2756 * scavenged, but this causes no harm. An easy check is done that the
2757 * scavenged bytes equals the number allocated in the previous
2760 * Write-protected pages are not scanned except if they are marked
2761 * dont_move in which case they may have been promoted and still have
2762 * pointers to the from space.
2764 * Write-protected pages could potentially be written by alloc however
2765 * to avoid having to handle re-scavenging of write-protected pages
2766 * gc_alloc() does not write to write-protected pages.
2768 * New areas of objects allocated are recorded alternatively in the two
2769 * new_areas arrays below. */
2770 static struct new_area new_areas_1[NUM_NEW_AREAS];
2771 static struct new_area new_areas_2[NUM_NEW_AREAS];
2773 /* Do one full scan of the new space generation. This is not enough to
2774 * complete the job as new objects may be added to the generation in
2775 * the process which are not scavenged. */
2777 scavenge_newspace_generation_one_scan(int generation)
2782 "/starting one full scan of newspace generation %d\n",
2784 for (i = 0; i < last_free_page; i++) {
2785 /* Note that this skips over open regions when it encounters them. */
2786 if ((page_table[i].allocated & BOXED_PAGE_FLAG)
2787 && (page_table[i].bytes_used != 0)
2788 && (page_table[i].gen == generation)
2789 && ((page_table[i].write_protected == 0)
2790 /* (This may be redundant as write_protected is now
2791 * cleared before promotion.) */
2792 || (page_table[i].dont_move == 1))) {
2796 /* The scavenge will start at the first_object_offset of page i.
2798 * We need to find the full extent of this contiguous
2799 * block in case objects span pages.
2801 * Now work forward until the end of this contiguous area
2802 * is found. A small area is preferred as there is a
2803 * better chance of its pages being write-protected. */
2804 for (last_page = i; ;last_page++) {
2805 /* If all pages are write-protected and movable,
2806 * then no need to scavenge */
2807 all_wp=all_wp && page_table[last_page].write_protected &&
2808 !page_table[last_page].dont_move;
2810 /* Check whether this is the last page in this
2811 * contiguous block */
2812 if ((page_table[last_page].bytes_used < PAGE_BYTES)
2813 /* Or it is PAGE_BYTES and is the last in the block */
2814 || (!(page_table[last_page+1].allocated & BOXED_PAGE_FLAG))
2815 || (page_table[last_page+1].bytes_used == 0)
2816 || (page_table[last_page+1].gen != generation)
2817 || (page_table[last_page+1].first_object_offset == 0))
2821 /* Do a limited check for write-protected pages. */
2825 size = (page_table[last_page].bytes_used
2826 + (last_page-i)*PAGE_BYTES
2827 - page_table[i].first_object_offset)/N_WORD_BYTES;
2828 new_areas_ignore_page = last_page;
2830 scavenge(page_address(i) +
2831 page_table[i].first_object_offset,
2839 "/done with one full scan of newspace generation %d\n",
2843 /* Do a complete scavenge of the newspace generation. */
2845 scavenge_newspace_generation(int generation)
2849 /* the new_areas array currently being written to by gc_alloc() */
2850 struct new_area (*current_new_areas)[] = &new_areas_1;
2851 long current_new_areas_index;
2853 /* the new_areas created by the previous scavenge cycle */
2854 struct new_area (*previous_new_areas)[] = NULL;
2855 long previous_new_areas_index;
2857 /* Flush the current regions updating the tables. */
2858 gc_alloc_update_all_page_tables();
2860 /* Turn on the recording of new areas by gc_alloc(). */
2861 new_areas = current_new_areas;
2862 new_areas_index = 0;
2864 /* Don't need to record new areas that get scavenged anyway during
2865 * scavenge_newspace_generation_one_scan. */
2866 record_new_objects = 1;
2868 /* Start with a full scavenge. */
2869 scavenge_newspace_generation_one_scan(generation);
2871 /* Record all new areas now. */
2872 record_new_objects = 2;
2874 /* Flush the current regions updating the tables. */
2875 gc_alloc_update_all_page_tables();
2877 /* Grab new_areas_index. */
2878 current_new_areas_index = new_areas_index;
2881 "The first scan is finished; current_new_areas_index=%d.\n",
2882 current_new_areas_index));*/
2884 while (current_new_areas_index > 0) {
2885 /* Move the current to the previous new areas */
2886 previous_new_areas = current_new_areas;
2887 previous_new_areas_index = current_new_areas_index;
2889 /* Scavenge all the areas in previous new areas. Any new areas
2890 * allocated are saved in current_new_areas. */
2892 /* Allocate an array for current_new_areas; alternating between
2893 * new_areas_1 and 2 */
2894 if (previous_new_areas == &new_areas_1)
2895 current_new_areas = &new_areas_2;
2897 current_new_areas = &new_areas_1;
2899 /* Set up for gc_alloc(). */
2900 new_areas = current_new_areas;
2901 new_areas_index = 0;
2903 /* Check whether previous_new_areas had overflowed. */
2904 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2906 /* New areas of objects allocated have been lost so need to do a
2907 * full scan to be sure! If this becomes a problem try
2908 * increasing NUM_NEW_AREAS. */
2910 SHOW("new_areas overflow, doing full scavenge");
2912 /* Don't need to record new areas that get scavenge anyway
2913 * during scavenge_newspace_generation_one_scan. */
2914 record_new_objects = 1;
2916 scavenge_newspace_generation_one_scan(generation);
2918 /* Record all new areas now. */
2919 record_new_objects = 2;
2921 /* Flush the current regions updating the tables. */
2922 gc_alloc_update_all_page_tables();
2926 /* Work through previous_new_areas. */
2927 for (i = 0; i < previous_new_areas_index; i++) {
2928 long page = (*previous_new_areas)[i].page;
2929 long offset = (*previous_new_areas)[i].offset;
2930 long size = (*previous_new_areas)[i].size / N_WORD_BYTES;
2931 gc_assert((*previous_new_areas)[i].size % N_WORD_BYTES == 0);
2932 scavenge(page_address(page)+offset, size);
2935 /* Flush the current regions updating the tables. */
2936 gc_alloc_update_all_page_tables();
2939 current_new_areas_index = new_areas_index;
2942 "The re-scan has finished; current_new_areas_index=%d.\n",
2943 current_new_areas_index));*/
2946 /* Turn off recording of areas allocated by gc_alloc(). */
2947 record_new_objects = 0;
2950 /* Check that none of the write_protected pages in this generation
2951 * have been written to. */
2952 for (i = 0; i < NUM_PAGES; i++) {
2953 if ((page_table[i].allocation != FREE_PAGE_FLAG)
2954 && (page_table[i].bytes_used != 0)
2955 && (page_table[i].gen == generation)
2956 && (page_table[i].write_protected_cleared != 0)
2957 && (page_table[i].dont_move == 0)) {
2958 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d",
2959 i, generation, page_table[i].dont_move);
2965 /* Un-write-protect all the pages in from_space. This is done at the
2966 * start of a GC else there may be many page faults while scavenging
2967 * the newspace (I've seen drive the system time to 99%). These pages
2968 * would need to be unprotected anyway before unmapping in
2969 * free_oldspace; not sure what effect this has on paging.. */
2971 unprotect_oldspace(void)
2975 for (i = 0; i < last_free_page; i++) {
2976 if ((page_table[i].allocated != FREE_PAGE_FLAG)
2977 && (page_table[i].bytes_used != 0)
2978 && (page_table[i].gen == from_space)) {
2981 page_start = (void *)page_address(i);
2983 /* Remove any write-protection. We should be able to rely
2984 * on the write-protect flag to avoid redundant calls. */
2985 if (page_table[i].write_protected) {
2986 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
2987 page_table[i].write_protected = 0;
2993 /* Work through all the pages and free any in from_space. This
2994 * assumes that all objects have been copied or promoted to an older
2995 * generation. Bytes_allocated and the generation bytes_allocated
2996 * counter are updated. The number of bytes freed is returned. */
3000 long bytes_freed = 0;
3001 long first_page, last_page;
3006 /* Find a first page for the next region of pages. */
3007 while ((first_page < last_free_page)
3008 && ((page_table[first_page].allocated == FREE_PAGE_FLAG)
3009 || (page_table[first_page].bytes_used == 0)
3010 || (page_table[first_page].gen != from_space)))
3013 if (first_page >= last_free_page)
3016 /* Find the last page of this region. */
3017 last_page = first_page;
3020 /* Free the page. */
3021 bytes_freed += page_table[last_page].bytes_used;
3022 generations[page_table[last_page].gen].bytes_allocated -=
3023 page_table[last_page].bytes_used;
3024 page_table[last_page].allocated = FREE_PAGE_FLAG;
3025 page_table[last_page].bytes_used = 0;
3027 /* Remove any write-protection. We should be able to rely
3028 * on the write-protect flag to avoid redundant calls. */
3030 void *page_start = (void *)page_address(last_page);
3032 if (page_table[last_page].write_protected) {
3033 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3034 page_table[last_page].write_protected = 0;
3039 while ((last_page < last_free_page)
3040 && (page_table[last_page].allocated != FREE_PAGE_FLAG)
3041 && (page_table[last_page].bytes_used != 0)
3042 && (page_table[last_page].gen == from_space));
3044 /* Zero pages from first_page to (last_page-1).
3046 * FIXME: Why not use os_zero(..) function instead of
3047 * hand-coding this again? (Check other gencgc_unmap_zero
3049 if (gencgc_unmap_zero) {
3050 void *page_start, *addr;
3052 page_start = (void *)page_address(first_page);
3054 os_invalidate(page_start, PAGE_BYTES*(last_page-first_page));
3055 addr = os_validate(page_start, PAGE_BYTES*(last_page-first_page));
3056 if (addr == NULL || addr != page_start) {
3057 lose("free_oldspace: page moved, 0x%08x ==> 0x%08x",page_start,
3063 page_start = (long *)page_address(first_page);
3064 memset(page_start, 0,PAGE_BYTES*(last_page-first_page));
3067 first_page = last_page;
3069 } while (first_page < last_free_page);
3071 bytes_allocated -= bytes_freed;
3076 /* Print some information about a pointer at the given address. */
3078 print_ptr(lispobj *addr)
3080 /* If addr is in the dynamic space then out the page information. */
3081 long pi1 = find_page_index((void*)addr);
3084 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %d dont_move %d\n",
3085 (unsigned long) addr,
3087 page_table[pi1].allocated,
3088 page_table[pi1].gen,
3089 page_table[pi1].bytes_used,
3090 page_table[pi1].first_object_offset,
3091 page_table[pi1].dont_move);
3092 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3105 extern long undefined_tramp;
3108 verify_space(lispobj *start, size_t words)
3110 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3111 int is_in_readonly_space =
3112 (READ_ONLY_SPACE_START <= (unsigned)start &&
3113 (unsigned)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3117 lispobj thing = *(lispobj*)start;
3119 if (is_lisp_pointer(thing)) {
3120 long page_index = find_page_index((void*)thing);
3121 long to_readonly_space =
3122 (READ_ONLY_SPACE_START <= thing &&
3123 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3124 long to_static_space =
3125 (STATIC_SPACE_START <= thing &&
3126 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3128 /* Does it point to the dynamic space? */
3129 if (page_index != -1) {
3130 /* If it's within the dynamic space it should point to a used
3131 * page. XX Could check the offset too. */
3132 if ((page_table[page_index].allocated != FREE_PAGE_FLAG)
3133 && (page_table[page_index].bytes_used == 0))
3134 lose ("Ptr %x @ %x sees free page.", thing, start);
3135 /* Check that it doesn't point to a forwarding pointer! */
3136 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3137 lose("Ptr %x @ %x sees forwarding ptr.", thing, start);
3139 /* Check that its not in the RO space as it would then be a
3140 * pointer from the RO to the dynamic space. */
3141 if (is_in_readonly_space) {
3142 lose("ptr to dynamic space %x from RO space %x",
3145 /* Does it point to a plausible object? This check slows
3146 * it down a lot (so it's commented out).
3148 * "a lot" is serious: it ate 50 minutes cpu time on
3149 * my duron 950 before I came back from lunch and
3152 * FIXME: Add a variable to enable this
3155 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3156 lose("ptr %x to invalid object %x", thing, start);
3160 /* Verify that it points to another valid space. */
3161 if (!to_readonly_space && !to_static_space
3162 && (thing != (unsigned)&undefined_tramp)) {
3163 lose("Ptr %x @ %x sees junk.", thing, start);
3167 if (!(fixnump(thing))) {
3169 switch(widetag_of(*start)) {
3172 case SIMPLE_VECTOR_WIDETAG:
3174 case COMPLEX_WIDETAG:
3175 case SIMPLE_ARRAY_WIDETAG:
3176 case COMPLEX_BASE_STRING_WIDETAG:
3177 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
3178 case COMPLEX_CHARACTER_STRING_WIDETAG:
3180 case COMPLEX_VECTOR_NIL_WIDETAG:
3181 case COMPLEX_BIT_VECTOR_WIDETAG:
3182 case COMPLEX_VECTOR_WIDETAG:
3183 case COMPLEX_ARRAY_WIDETAG:
3184 case CLOSURE_HEADER_WIDETAG:
3185 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3186 case VALUE_CELL_HEADER_WIDETAG:
3187 case SYMBOL_HEADER_WIDETAG:
3188 case CHARACTER_WIDETAG:
3189 case UNBOUND_MARKER_WIDETAG:
3190 case INSTANCE_HEADER_WIDETAG:
3195 case CODE_HEADER_WIDETAG:
3197 lispobj object = *start;
3199 long nheader_words, ncode_words, nwords;
3201 struct simple_fun *fheaderp;
3203 code = (struct code *) start;
3205 /* Check that it's not in the dynamic space.
3206 * FIXME: Isn't is supposed to be OK for code
3207 * objects to be in the dynamic space these days? */
3208 if (is_in_dynamic_space
3209 /* It's ok if it's byte compiled code. The trace
3210 * table offset will be a fixnum if it's x86
3211 * compiled code - check.
3213 * FIXME: #^#@@! lack of abstraction here..
3214 * This line can probably go away now that
3215 * there's no byte compiler, but I've got
3216 * too much to worry about right now to try
3217 * to make sure. -- WHN 2001-10-06 */
3218 && fixnump(code->trace_table_offset)
3219 /* Only when enabled */
3220 && verify_dynamic_code_check) {
3222 "/code object at %x in the dynamic space\n",
3226 ncode_words = fixnum_value(code->code_size);
3227 nheader_words = HeaderValue(object);
3228 nwords = ncode_words + nheader_words;
3229 nwords = CEILING(nwords, 2);
3230 /* Scavenge the boxed section of the code data block */
3231 verify_space(start + 1, nheader_words - 1);
3233 /* Scavenge the boxed section of each function
3234 * object in the code data block. */
3235 fheaderl = code->entry_points;
3236 while (fheaderl != NIL) {
3238 (struct simple_fun *) native_pointer(fheaderl);
3239 gc_assert(widetag_of(fheaderp->header) == SIMPLE_FUN_HEADER_WIDETAG);
3240 verify_space(&fheaderp->name, 1);
3241 verify_space(&fheaderp->arglist, 1);
3242 verify_space(&fheaderp->type, 1);
3243 fheaderl = fheaderp->next;
3249 /* unboxed objects */
3250 case BIGNUM_WIDETAG:
3251 case SINGLE_FLOAT_WIDETAG:
3252 case DOUBLE_FLOAT_WIDETAG:
3253 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3254 case LONG_FLOAT_WIDETAG:
3256 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3257 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3259 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3260 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3262 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3263 case COMPLEX_LONG_FLOAT_WIDETAG:
3265 case SIMPLE_BASE_STRING_WIDETAG:
3266 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
3267 case SIMPLE_CHARACTER_STRING_WIDETAG:
3269 case SIMPLE_BIT_VECTOR_WIDETAG:
3270 case SIMPLE_ARRAY_NIL_WIDETAG:
3271 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3272 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3273 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3274 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3275 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3276 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3277 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
3278 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3280 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3281 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3282 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
3283 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
3285 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
3286 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
3288 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
3289 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
3291 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3292 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3294 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3295 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3297 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3298 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3300 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3301 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3303 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
3304 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
3306 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
3307 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
3309 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3310 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3311 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3312 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3314 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3315 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3317 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3318 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3320 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3321 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3324 case WEAK_POINTER_WIDETAG:
3325 count = (sizetab[widetag_of(*start)])(start);
3341 /* FIXME: It would be nice to make names consistent so that
3342 * foo_size meant size *in* *bytes* instead of size in some
3343 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3344 * Some counts of lispobjs are called foo_count; it might be good
3345 * to grep for all foo_size and rename the appropriate ones to
3347 long read_only_space_size =
3348 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3349 - (lispobj*)READ_ONLY_SPACE_START;
3350 long static_space_size =
3351 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3352 - (lispobj*)STATIC_SPACE_START;
3354 for_each_thread(th) {
3355 long binding_stack_size =
3356 (lispobj*)SymbolValue(BINDING_STACK_POINTER,th)
3357 - (lispobj*)th->binding_stack_start;
3358 verify_space(th->binding_stack_start, binding_stack_size);
3360 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3361 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3365 verify_generation(int generation)
3369 for (i = 0; i < last_free_page; i++) {
3370 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3371 && (page_table[i].bytes_used != 0)
3372 && (page_table[i].gen == generation)) {
3374 int region_allocation = page_table[i].allocated;
3376 /* This should be the start of a contiguous block */
3377 gc_assert(page_table[i].first_object_offset == 0);
3379 /* Need to find the full extent of this contiguous block in case
3380 objects span pages. */
3382 /* Now work forward until the end of this contiguous area is
3384 for (last_page = i; ;last_page++)
3385 /* Check whether this is the last page in this contiguous
3387 if ((page_table[last_page].bytes_used < PAGE_BYTES)
3388 /* Or it is PAGE_BYTES and is the last in the block */
3389 || (page_table[last_page+1].allocated != region_allocation)
3390 || (page_table[last_page+1].bytes_used == 0)
3391 || (page_table[last_page+1].gen != generation)
3392 || (page_table[last_page+1].first_object_offset == 0))
3395 verify_space(page_address(i), (page_table[last_page].bytes_used
3396 + (last_page-i)*PAGE_BYTES)/N_WORD_BYTES);
3402 /* Check that all the free space is zero filled. */
3404 verify_zero_fill(void)
3408 for (page = 0; page < last_free_page; page++) {
3409 if (page_table[page].allocated == FREE_PAGE_FLAG) {
3410 /* The whole page should be zero filled. */
3411 long *start_addr = (long *)page_address(page);
3414 for (i = 0; i < size; i++) {
3415 if (start_addr[i] != 0) {
3416 lose("free page not zero at %x", start_addr + i);
3420 long free_bytes = PAGE_BYTES - page_table[page].bytes_used;
3421 if (free_bytes > 0) {
3422 long *start_addr = (long *)((unsigned)page_address(page)
3423 + page_table[page].bytes_used);
3424 long size = free_bytes / N_WORD_BYTES;
3426 for (i = 0; i < size; i++) {
3427 if (start_addr[i] != 0) {
3428 lose("free region not zero at %x", start_addr + i);
3436 /* External entry point for verify_zero_fill */
3438 gencgc_verify_zero_fill(void)
3440 /* Flush the alloc regions updating the tables. */
3441 gc_alloc_update_all_page_tables();
3442 SHOW("verifying zero fill");
3447 verify_dynamic_space(void)
3451 for (i = 0; i < NUM_GENERATIONS; i++)
3452 verify_generation(i);
3454 if (gencgc_enable_verify_zero_fill)
3458 /* Write-protect all the dynamic boxed pages in the given generation. */
3460 write_protect_generation_pages(int generation)
3464 gc_assert(generation < NUM_GENERATIONS);
3466 for (i = 0; i < last_free_page; i++)
3467 if ((page_table[i].allocated == BOXED_PAGE_FLAG)
3468 && (page_table[i].bytes_used != 0)
3469 && !page_table[i].dont_move
3470 && (page_table[i].gen == generation)) {
3473 page_start = (void *)page_address(i);
3475 os_protect(page_start,
3477 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3479 /* Note the page as protected in the page tables. */
3480 page_table[i].write_protected = 1;
3483 if (gencgc_verbose > 1) {
3485 "/write protected %d of %d pages in generation %d\n",
3486 count_write_protect_generation_pages(generation),
3487 count_generation_pages(generation),
3492 /* Garbage collect a generation. If raise is 0 then the remains of the
3493 * generation are not raised to the next generation. */
3495 garbage_collect_generation(int generation, int raise)
3497 unsigned long bytes_freed;
3499 unsigned long static_space_size;
3501 gc_assert(generation <= (NUM_GENERATIONS-1));
3503 /* The oldest generation can't be raised. */
3504 gc_assert((generation != (NUM_GENERATIONS-1)) || (raise == 0));
3506 /* Initialize the weak pointer list. */
3507 weak_pointers = NULL;
3509 /* When a generation is not being raised it is transported to a
3510 * temporary generation (NUM_GENERATIONS), and lowered when
3511 * done. Set up this new generation. There should be no pages
3512 * allocated to it yet. */
3514 gc_assert(generations[NUM_GENERATIONS].bytes_allocated == 0);
3517 /* Set the global src and dest. generations */
3518 from_space = generation;
3520 new_space = generation+1;
3522 new_space = NUM_GENERATIONS;
3524 /* Change to a new space for allocation, resetting the alloc_start_page */
3525 gc_alloc_generation = new_space;
3526 generations[new_space].alloc_start_page = 0;
3527 generations[new_space].alloc_unboxed_start_page = 0;
3528 generations[new_space].alloc_large_start_page = 0;
3529 generations[new_space].alloc_large_unboxed_start_page = 0;
3531 /* Before any pointers are preserved, the dont_move flags on the
3532 * pages need to be cleared. */
3533 for (i = 0; i < last_free_page; i++)
3534 if(page_table[i].gen==from_space)
3535 page_table[i].dont_move = 0;
3537 /* Un-write-protect the old-space pages. This is essential for the
3538 * promoted pages as they may contain pointers into the old-space
3539 * which need to be scavenged. It also helps avoid unnecessary page
3540 * faults as forwarding pointers are written into them. They need to
3541 * be un-protected anyway before unmapping later. */
3542 unprotect_oldspace();
3544 /* Scavenge the stacks' conservative roots. */
3546 /* there are potentially two stacks for each thread: the main
3547 * stack, which may contain Lisp pointers, and the alternate stack.
3548 * We don't ever run Lisp code on the altstack, but it may
3549 * host a sigcontext with lisp objects in it */
3551 /* what we need to do: (1) find the stack pointer for the main
3552 * stack; scavenge it (2) find the interrupt context on the
3553 * alternate stack that might contain lisp values, and scavenge
3556 /* we assume that none of the preceding applies to the thread that
3557 * initiates GC. If you ever call GC from inside an altstack
3558 * handler, you will lose. */
3559 for_each_thread(th) {
3561 void **esp=(void **)-1;
3562 #ifdef LISP_FEATURE_SB_THREAD
3564 if(th==arch_os_get_current_thread()) {
3565 esp = (void **) &raise;
3568 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3569 for(i=free-1;i>=0;i--) {
3570 os_context_t *c=th->interrupt_contexts[i];
3571 esp1 = (void **) *os_context_register_addr(c,reg_ESP);
3572 if(esp1>=th->control_stack_start&& esp1<th->control_stack_end){
3573 if(esp1<esp) esp=esp1;
3574 for(ptr = (void **)(c+1); ptr>=(void **)c; ptr--) {
3575 preserve_pointer(*ptr);
3581 esp = (void **) &raise;
3583 for (ptr = (void **)th->control_stack_end; ptr > esp; ptr--) {
3584 preserve_pointer(*ptr);
3589 if (gencgc_verbose > 1) {
3590 long num_dont_move_pages = count_dont_move_pages();
3592 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3593 num_dont_move_pages,
3594 num_dont_move_pages * PAGE_BYTES);
3598 /* Scavenge all the rest of the roots. */
3600 /* Scavenge the Lisp functions of the interrupt handlers, taking
3601 * care to avoid SIG_DFL and SIG_IGN. */
3602 for_each_thread(th) {
3603 struct interrupt_data *data=th->interrupt_data;
3604 for (i = 0; i < NSIG; i++) {
3605 union interrupt_handler handler = data->interrupt_handlers[i];
3606 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3607 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3608 scavenge((lispobj *)(data->interrupt_handlers + i), 1);
3612 /* Scavenge the binding stacks. */
3615 for_each_thread(th) {
3616 long len= (lispobj *)SymbolValue(BINDING_STACK_POINTER,th) -
3617 th->binding_stack_start;
3618 scavenge((lispobj *) th->binding_stack_start,len);
3619 #ifdef LISP_FEATURE_SB_THREAD
3620 /* do the tls as well */
3621 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
3622 (sizeof (struct thread))/(sizeof (lispobj));
3623 scavenge((lispobj *) (th+1),len);
3628 /* The original CMU CL code had scavenge-read-only-space code
3629 * controlled by the Lisp-level variable
3630 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3631 * wasn't documented under what circumstances it was useful or
3632 * safe to turn it on, so it's been turned off in SBCL. If you
3633 * want/need this functionality, and can test and document it,
3634 * please submit a patch. */
3636 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3637 unsigned long read_only_space_size =
3638 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3639 (lispobj*)READ_ONLY_SPACE_START;
3641 "/scavenge read only space: %d bytes\n",
3642 read_only_space_size * sizeof(lispobj)));
3643 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3647 /* Scavenge static space. */
3649 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3650 (lispobj *)STATIC_SPACE_START;
3651 if (gencgc_verbose > 1) {
3653 "/scavenge static space: %d bytes\n",
3654 static_space_size * sizeof(lispobj)));
3656 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3658 /* All generations but the generation being GCed need to be
3659 * scavenged. The new_space generation needs special handling as
3660 * objects may be moved in - it is handled separately below. */
3661 for (i = 0; i < NUM_GENERATIONS; i++) {
3662 if ((i != generation) && (i != new_space)) {
3663 scavenge_generation(i);
3667 /* Finally scavenge the new_space generation. Keep going until no
3668 * more objects are moved into the new generation */
3669 scavenge_newspace_generation(new_space);
3671 /* FIXME: I tried reenabling this check when debugging unrelated
3672 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3673 * Since the current GC code seems to work well, I'm guessing that
3674 * this debugging code is just stale, but I haven't tried to
3675 * figure it out. It should be figured out and then either made to
3676 * work or just deleted. */
3677 #define RESCAN_CHECK 0
3679 /* As a check re-scavenge the newspace once; no new objects should
3682 long old_bytes_allocated = bytes_allocated;
3683 long bytes_allocated;
3685 /* Start with a full scavenge. */
3686 scavenge_newspace_generation_one_scan(new_space);
3688 /* Flush the current regions, updating the tables. */
3689 gc_alloc_update_all_page_tables();
3691 bytes_allocated = bytes_allocated - old_bytes_allocated;
3693 if (bytes_allocated != 0) {
3694 lose("Rescan of new_space allocated %d more bytes.",
3700 scan_weak_pointers();
3702 /* Flush the current regions, updating the tables. */
3703 gc_alloc_update_all_page_tables();
3705 /* Free the pages in oldspace, but not those marked dont_move. */
3706 bytes_freed = free_oldspace();
3708 /* If the GC is not raising the age then lower the generation back
3709 * to its normal generation number */
3711 for (i = 0; i < last_free_page; i++)
3712 if ((page_table[i].bytes_used != 0)
3713 && (page_table[i].gen == NUM_GENERATIONS))
3714 page_table[i].gen = generation;
3715 gc_assert(generations[generation].bytes_allocated == 0);
3716 generations[generation].bytes_allocated =
3717 generations[NUM_GENERATIONS].bytes_allocated;
3718 generations[NUM_GENERATIONS].bytes_allocated = 0;
3721 /* Reset the alloc_start_page for generation. */
3722 generations[generation].alloc_start_page = 0;
3723 generations[generation].alloc_unboxed_start_page = 0;
3724 generations[generation].alloc_large_start_page = 0;
3725 generations[generation].alloc_large_unboxed_start_page = 0;
3727 if (generation >= verify_gens) {
3731 verify_dynamic_space();
3734 /* Set the new gc trigger for the GCed generation. */
3735 generations[generation].gc_trigger =
3736 generations[generation].bytes_allocated
3737 + generations[generation].bytes_consed_between_gc;
3740 generations[generation].num_gc = 0;
3742 ++generations[generation].num_gc;
3745 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3747 update_x86_dynamic_space_free_pointer(void)
3749 long last_page = -1;
3752 for (i = 0; i < last_free_page; i++)
3753 if ((page_table[i].allocated != FREE_PAGE_FLAG)
3754 && (page_table[i].bytes_used != 0))
3757 last_free_page = last_page+1;
3759 SetSymbolValue(ALLOCATION_POINTER,
3760 (lispobj)(((char *)heap_base) + last_free_page*PAGE_BYTES),0);
3761 return 0; /* dummy value: return something ... */
3764 /* GC all generations newer than last_gen, raising the objects in each
3765 * to the next older generation - we finish when all generations below
3766 * last_gen are empty. Then if last_gen is due for a GC, or if
3767 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3768 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3770 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3771 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3774 collect_garbage(unsigned last_gen)
3781 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3783 if (last_gen > NUM_GENERATIONS) {
3785 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3790 /* Flush the alloc regions updating the tables. */
3791 gc_alloc_update_all_page_tables();
3793 /* Verify the new objects created by Lisp code. */
3794 if (pre_verify_gen_0) {
3795 FSHOW((stderr, "pre-checking generation 0\n"));
3796 verify_generation(0);
3799 if (gencgc_verbose > 1)
3800 print_generation_stats(0);
3803 /* Collect the generation. */
3805 if (gen >= gencgc_oldest_gen_to_gc) {
3806 /* Never raise the oldest generation. */
3811 || (generations[gen].num_gc >= generations[gen].trigger_age);
3814 if (gencgc_verbose > 1) {
3816 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3819 generations[gen].bytes_allocated,
3820 generations[gen].gc_trigger,
3821 generations[gen].num_gc));
3824 /* If an older generation is being filled, then update its
3827 generations[gen+1].cum_sum_bytes_allocated +=
3828 generations[gen+1].bytes_allocated;
3831 garbage_collect_generation(gen, raise);
3833 /* Reset the memory age cum_sum. */
3834 generations[gen].cum_sum_bytes_allocated = 0;
3836 if (gencgc_verbose > 1) {
3837 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3838 print_generation_stats(0);
3842 } while ((gen <= gencgc_oldest_gen_to_gc)
3843 && ((gen < last_gen)
3844 || ((gen <= gencgc_oldest_gen_to_gc)
3846 && (generations[gen].bytes_allocated
3847 > generations[gen].gc_trigger)
3848 && (gen_av_mem_age(gen)
3849 > generations[gen].min_av_mem_age))));
3851 /* Now if gen-1 was raised all generations before gen are empty.
3852 * If it wasn't raised then all generations before gen-1 are empty.
3854 * Now objects within this gen's pages cannot point to younger
3855 * generations unless they are written to. This can be exploited
3856 * by write-protecting the pages of gen; then when younger
3857 * generations are GCed only the pages which have been written
3862 gen_to_wp = gen - 1;
3864 /* There's not much point in WPing pages in generation 0 as it is
3865 * never scavenged (except promoted pages). */
3866 if ((gen_to_wp > 0) && enable_page_protection) {
3867 /* Check that they are all empty. */
3868 for (i = 0; i < gen_to_wp; i++) {
3869 if (generations[i].bytes_allocated)
3870 lose("trying to write-protect gen. %d when gen. %d nonempty",
3873 write_protect_generation_pages(gen_to_wp);
3876 /* Set gc_alloc() back to generation 0. The current regions should
3877 * be flushed after the above GCs. */
3878 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3879 gc_alloc_generation = 0;
3881 update_x86_dynamic_space_free_pointer();
3882 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3884 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
3886 SHOW("returning from collect_garbage");
3889 /* This is called by Lisp PURIFY when it is finished. All live objects
3890 * will have been moved to the RO and Static heaps. The dynamic space
3891 * will need a full re-initialization. We don't bother having Lisp
3892 * PURIFY flush the current gc_alloc() region, as the page_tables are
3893 * re-initialized, and every page is zeroed to be sure. */
3899 if (gencgc_verbose > 1)
3900 SHOW("entering gc_free_heap");
3902 for (page = 0; page < NUM_PAGES; page++) {
3903 /* Skip free pages which should already be zero filled. */
3904 if (page_table[page].allocated != FREE_PAGE_FLAG) {
3905 void *page_start, *addr;
3907 /* Mark the page free. The other slots are assumed invalid
3908 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
3909 * should not be write-protected -- except that the
3910 * generation is used for the current region but it sets
3912 page_table[page].allocated = FREE_PAGE_FLAG;
3913 page_table[page].bytes_used = 0;
3915 /* Zero the page. */
3916 page_start = (void *)page_address(page);
3918 /* First, remove any write-protection. */
3919 os_protect(page_start, PAGE_BYTES, OS_VM_PROT_ALL);
3920 page_table[page].write_protected = 0;
3922 os_invalidate(page_start,PAGE_BYTES);
3923 addr = os_validate(page_start,PAGE_BYTES);
3924 if (addr == NULL || addr != page_start) {
3925 lose("gc_free_heap: page moved, 0x%08x ==> 0x%08x",
3929 } else if (gencgc_zero_check_during_free_heap) {
3930 /* Double-check that the page is zero filled. */
3931 long *page_start, i;
3932 gc_assert(page_table[page].allocated == FREE_PAGE_FLAG);
3933 gc_assert(page_table[page].bytes_used == 0);
3934 page_start = (long *)page_address(page);
3935 for (i=0; i<1024; i++) {
3936 if (page_start[i] != 0) {
3937 lose("free region not zero at %x", page_start + i);
3943 bytes_allocated = 0;
3945 /* Initialize the generations. */
3946 for (page = 0; page < NUM_GENERATIONS; page++) {
3947 generations[page].alloc_start_page = 0;
3948 generations[page].alloc_unboxed_start_page = 0;
3949 generations[page].alloc_large_start_page = 0;
3950 generations[page].alloc_large_unboxed_start_page = 0;
3951 generations[page].bytes_allocated = 0;
3952 generations[page].gc_trigger = 2000000;
3953 generations[page].num_gc = 0;
3954 generations[page].cum_sum_bytes_allocated = 0;
3957 if (gencgc_verbose > 1)
3958 print_generation_stats(0);
3960 /* Initialize gc_alloc(). */
3961 gc_alloc_generation = 0;
3963 gc_set_region_empty(&boxed_region);
3964 gc_set_region_empty(&unboxed_region);
3967 SetSymbolValue(ALLOCATION_POINTER, (lispobj)((char *)heap_base),0);
3969 if (verify_after_free_heap) {
3970 /* Check whether purify has left any bad pointers. */
3972 SHOW("checking after free_heap\n");
3983 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
3984 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
3985 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
3987 heap_base = (void*)DYNAMIC_SPACE_START;
3989 /* Initialize each page structure. */
3990 for (i = 0; i < NUM_PAGES; i++) {
3991 /* Initialize all pages as free. */
3992 page_table[i].allocated = FREE_PAGE_FLAG;
3993 page_table[i].bytes_used = 0;
3995 /* Pages are not write-protected at startup. */
3996 page_table[i].write_protected = 0;
3999 bytes_allocated = 0;
4001 /* Initialize the generations.
4003 * FIXME: very similar to code in gc_free_heap(), should be shared */
4004 for (i = 0; i < NUM_GENERATIONS; i++) {
4005 generations[i].alloc_start_page = 0;
4006 generations[i].alloc_unboxed_start_page = 0;
4007 generations[i].alloc_large_start_page = 0;
4008 generations[i].alloc_large_unboxed_start_page = 0;
4009 generations[i].bytes_allocated = 0;
4010 generations[i].gc_trigger = 2000000;
4011 generations[i].num_gc = 0;
4012 generations[i].cum_sum_bytes_allocated = 0;
4013 /* the tune-able parameters */
4014 generations[i].bytes_consed_between_gc = 2000000;
4015 generations[i].trigger_age = 1;
4016 generations[i].min_av_mem_age = 0.75;
4019 /* Initialize gc_alloc. */
4020 gc_alloc_generation = 0;
4021 gc_set_region_empty(&boxed_region);
4022 gc_set_region_empty(&unboxed_region);
4028 /* Pick up the dynamic space from after a core load.
4030 * The ALLOCATION_POINTER points to the end of the dynamic space.
4034 gencgc_pickup_dynamic(void)
4037 long alloc_ptr = SymbolValue(ALLOCATION_POINTER,0);
4038 lispobj *prev=(lispobj *)page_address(page);
4041 lispobj *first,*ptr= (lispobj *)page_address(page);
4042 page_table[page].allocated = BOXED_PAGE_FLAG;
4043 page_table[page].gen = 0;
4044 page_table[page].bytes_used = PAGE_BYTES;
4045 page_table[page].large_object = 0;
4047 first=search_space(prev,(ptr+2)-prev,ptr);
4048 if(ptr == first) prev=ptr;
4049 page_table[page].first_object_offset =
4050 (void *)prev - page_address(page);
4052 } while (page_address(page) < alloc_ptr);
4054 generations[0].bytes_allocated = PAGE_BYTES*page;
4055 bytes_allocated = PAGE_BYTES*page;
4061 gc_initialize_pointers(void)
4063 gencgc_pickup_dynamic();
4069 /* alloc(..) is the external interface for memory allocation. It
4070 * allocates to generation 0. It is not called from within the garbage
4071 * collector as it is only external uses that need the check for heap
4072 * size (GC trigger) and to disable the interrupts (interrupts are
4073 * always disabled during a GC).
4075 * The vops that call alloc(..) assume that the returned space is zero-filled.
4076 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4078 * The check for a GC trigger is only performed when the current
4079 * region is full, so in most cases it's not needed. */
4084 struct thread *th=arch_os_get_current_thread();
4085 struct alloc_region *region=
4086 #ifdef LISP_FEATURE_SB_THREAD
4087 th ? &(th->alloc_region) : &boxed_region;
4092 void *new_free_pointer;
4093 gc_assert(nbytes>0);
4094 /* Check for alignment allocation problems. */
4095 gc_assert((((unsigned)region->free_pointer & LOWTAG_MASK) == 0)
4096 && ((nbytes & LOWTAG_MASK) == 0));
4099 /* there are a few places in the C code that allocate data in the
4100 * heap before Lisp starts. This is before interrupts are enabled,
4101 * so we don't need to check for pseudo-atomic */
4102 #ifdef LISP_FEATURE_SB_THREAD
4103 if(!SymbolValue(PSEUDO_ATOMIC_ATOMIC,th)) {
4105 fprintf(stderr, "fatal error in thread 0x%x, pid=%d\n",
4107 __asm__("movl %fs,%0" : "=r" (fs) : );
4108 fprintf(stderr, "fs is %x, th->tls_cookie=%x \n",
4109 debug_get_fs(),th->tls_cookie);
4110 lose("If you see this message before 2004.01.31, mail details to sbcl-devel\n");
4113 gc_assert(SymbolValue(PSEUDO_ATOMIC_ATOMIC,th));
4117 /* maybe we can do this quickly ... */
4118 new_free_pointer = region->free_pointer + nbytes;
4119 if (new_free_pointer <= region->end_addr) {
4120 new_obj = (void*)(region->free_pointer);
4121 region->free_pointer = new_free_pointer;
4122 return(new_obj); /* yup */
4125 /* we have to go the long way around, it seems. Check whether
4126 * we should GC in the near future
4128 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4129 /* set things up so that GC happens when we finish the PA
4130 * section. We only do this if there wasn't a pending handler
4131 * already, in case it was a gc. If it wasn't a GC, the next
4132 * allocation will get us back to this point anyway, so no harm done
4134 struct interrupt_data *data=th->interrupt_data;
4135 if(!data->pending_handler)
4136 maybe_defer_handler(interrupt_maybe_gc_int,data,0,0,0);
4138 new_obj = gc_alloc_with_region(nbytes,0,region,0);
4143 * shared support for the OS-dependent signal handlers which
4144 * catch GENCGC-related write-protect violations
4147 void unhandled_sigmemoryfault(void);
4149 /* Depending on which OS we're running under, different signals might
4150 * be raised for a violation of write protection in the heap. This
4151 * function factors out the common generational GC magic which needs
4152 * to invoked in this case, and should be called from whatever signal
4153 * handler is appropriate for the OS we're running under.
4155 * Return true if this signal is a normal generational GC thing that
4156 * we were able to handle, or false if it was abnormal and control
4157 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4160 gencgc_handle_wp_violation(void* fault_addr)
4162 long page_index = find_page_index(fault_addr);
4164 #ifdef QSHOW_SIGNALS
4165 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4166 fault_addr, page_index));
4169 /* Check whether the fault is within the dynamic space. */
4170 if (page_index == (-1)) {
4172 /* It can be helpful to be able to put a breakpoint on this
4173 * case to help diagnose low-level problems. */
4174 unhandled_sigmemoryfault();
4176 /* not within the dynamic space -- not our responsibility */
4180 if (page_table[page_index].write_protected) {
4181 /* Unprotect the page. */
4182 os_protect(page_address(page_index), PAGE_BYTES, OS_VM_PROT_ALL);
4183 page_table[page_index].write_protected_cleared = 1;
4184 page_table[page_index].write_protected = 0;
4186 /* The only acceptable reason for this signal on a heap
4187 * access is that GENCGC write-protected the page.
4188 * However, if two CPUs hit a wp page near-simultaneously,
4189 * we had better not have the second one lose here if it
4190 * does this test after the first one has already set wp=0
4192 if(page_table[page_index].write_protected_cleared != 1)
4193 lose("fault in heap page not marked as write-protected");
4195 /* Don't worry, we can handle it. */
4199 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4200 * it's not just a case of the program hitting the write barrier, and
4201 * are about to let Lisp deal with it. It's basically just a
4202 * convenient place to set a gdb breakpoint. */
4204 unhandled_sigmemoryfault()
4207 void gc_alloc_update_all_page_tables(void)
4209 /* Flush the alloc regions updating the tables. */
4212 gc_alloc_update_page_tables(0, &th->alloc_region);
4213 gc_alloc_update_page_tables(1, &unboxed_region);
4214 gc_alloc_update_page_tables(0, &boxed_region);
4217 gc_set_region_empty(struct alloc_region *region)
4219 region->first_page = 0;
4220 region->last_page = -1;
4221 region->start_addr = page_address(0);
4222 region->free_pointer = page_address(0);
4223 region->end_addr = page_address(0);