2 * GENerational Conservative Garbage Collector for SBCL
6 * This software is part of the SBCL system. See the README file for
9 * This software is derived from the CMU CL system, which was
10 * written at Carnegie Mellon University and released into the
11 * public domain. The software is in the public domain and is
12 * provided with absolutely no warranty. See the COPYING and CREDITS
13 * files for more information.
17 * For a review of garbage collection techniques (e.g. generational
18 * GC) and terminology (e.g. "scavenging") see Paul R. Wilson,
19 * "Uniprocessor Garbage Collection Techniques". As of 20000618, this
20 * had been accepted for _ACM Computing Surveys_ and was available
21 * as a PostScript preprint through
22 * <http://www.cs.utexas.edu/users/oops/papers.html>
24 * <ftp://ftp.cs.utexas.edu/pub/garbage/bigsurv.ps>.
37 #include "interrupt.h"
42 #include "gc-internal.h"
44 #include "pseudo-atomic.h"
46 #include "genesis/vector.h"
47 #include "genesis/weak-pointer.h"
48 #include "genesis/fdefn.h"
49 #include "genesis/simple-fun.h"
51 #include "genesis/hash-table.h"
52 #include "genesis/instance.h"
53 #include "genesis/layout.h"
55 #if defined(LUTEX_WIDETAG)
56 #include "pthread-lutex.h"
58 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
59 #include "genesis/cons.h"
62 /* forward declarations */
63 page_index_t gc_find_freeish_pages(long *restart_page_ptr, long nbytes,
71 /* Generations 0-5 are normal collected generations, 6 is only used as
72 * scratch space by the collector, and should never get collected.
75 SCRATCH_GENERATION = PSEUDO_STATIC_GENERATION+1,
79 /* Should we use page protection to help avoid the scavenging of pages
80 * that don't have pointers to younger generations? */
81 boolean enable_page_protection = 1;
83 /* the minimum size (in bytes) for a large object*/
84 long large_object_size = 4 * GENCGC_ALLOC_GRANULARITY;
91 /* the verbosity level. All non-error messages are disabled at level 0;
92 * and only a few rare messages are printed at level 1. */
94 boolean gencgc_verbose = 1;
96 boolean gencgc_verbose = 0;
99 /* FIXME: At some point enable the various error-checking things below
100 * and see what they say. */
102 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
103 * Set verify_gens to HIGHEST_NORMAL_GENERATION + 1 to disable this kind of
105 generation_index_t verify_gens = HIGHEST_NORMAL_GENERATION + 1;
107 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
108 boolean pre_verify_gen_0 = 0;
110 /* Should we check for bad pointers after gc_free_heap is called
111 * from Lisp PURIFY? */
112 boolean verify_after_free_heap = 0;
114 /* Should we print a note when code objects are found in the dynamic space
115 * during a heap verify? */
116 boolean verify_dynamic_code_check = 0;
118 /* Should we check code objects for fixup errors after they are transported? */
119 boolean check_code_fixups = 0;
121 /* Should we check that newly allocated regions are zero filled? */
122 boolean gencgc_zero_check = 0;
124 /* Should we check that the free space is zero filled? */
125 boolean gencgc_enable_verify_zero_fill = 0;
127 /* Should we check that free pages are zero filled during gc_free_heap
128 * called after Lisp PURIFY? */
129 boolean gencgc_zero_check_during_free_heap = 0;
131 /* When loading a core, don't do a full scan of the memory for the
132 * memory region boundaries. (Set to true by coreparse.c if the core
133 * contained a pagetable entry).
135 boolean gencgc_partial_pickup = 0;
137 /* If defined, free pages are read-protected to ensure that nothing
141 /* #define READ_PROTECT_FREE_PAGES */
145 * GC structures and variables
148 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
149 unsigned long bytes_allocated = 0;
150 unsigned long auto_gc_trigger = 0;
152 /* the source and destination generations. These are set before a GC starts
154 generation_index_t from_space;
155 generation_index_t new_space;
157 /* Set to 1 when in GC */
158 boolean gc_active_p = 0;
160 /* should the GC be conservative on stack. If false (only right before
161 * saving a core), don't scan the stack / mark pages dont_move. */
162 static boolean conservative_stack = 1;
164 /* An array of page structures is allocated on gc initialization.
165 * This helps quickly map between an address its page structure.
166 * page_table_pages is set from the size of the dynamic space. */
167 page_index_t page_table_pages;
168 struct page *page_table;
170 static inline boolean page_allocated_p(page_index_t page) {
171 return (page_table[page].allocated != FREE_PAGE_FLAG);
174 static inline boolean page_no_region_p(page_index_t page) {
175 return !(page_table[page].allocated & OPEN_REGION_PAGE_FLAG);
178 static inline boolean page_allocated_no_region_p(page_index_t page) {
179 return ((page_table[page].allocated & (UNBOXED_PAGE_FLAG | BOXED_PAGE_FLAG))
180 && page_no_region_p(page));
183 static inline boolean page_free_p(page_index_t page) {
184 return (page_table[page].allocated == FREE_PAGE_FLAG);
187 static inline boolean page_boxed_p(page_index_t page) {
188 return (page_table[page].allocated & BOXED_PAGE_FLAG);
191 static inline boolean code_page_p(page_index_t page) {
192 return (page_table[page].allocated & CODE_PAGE_FLAG);
195 static inline boolean page_boxed_no_region_p(page_index_t page) {
196 return page_boxed_p(page) && page_no_region_p(page);
199 static inline boolean page_unboxed_p(page_index_t page) {
200 /* Both flags set == boxed code page */
201 return ((page_table[page].allocated & UNBOXED_PAGE_FLAG)
202 && !page_boxed_p(page));
205 static inline boolean protect_page_p(page_index_t page, generation_index_t generation) {
206 return (page_boxed_no_region_p(page)
207 && (page_table[page].bytes_used != 0)
208 && !page_table[page].dont_move
209 && (page_table[page].gen == generation));
212 /* To map addresses to page structures the address of the first page
214 static void *heap_base = NULL;
216 /* Calculate the start address for the given page number. */
218 page_address(page_index_t page_num)
220 return (heap_base + (page_num * GENCGC_CARD_BYTES));
223 /* Calculate the address where the allocation region associated with
224 * the page starts. */
226 page_region_start(page_index_t page_index)
228 return page_address(page_index)-page_table[page_index].region_start_offset;
231 /* Find the page index within the page_table for the given
232 * address. Return -1 on failure. */
234 find_page_index(void *addr)
236 if (addr >= heap_base) {
237 page_index_t index = ((pointer_sized_uint_t)addr -
238 (pointer_sized_uint_t)heap_base) / GENCGC_CARD_BYTES;
239 if (index < page_table_pages)
246 npage_bytes(long npages)
248 gc_assert(npages>=0);
249 return ((unsigned long)npages)*GENCGC_CARD_BYTES;
252 /* Check that X is a higher address than Y and return offset from Y to
255 size_t void_diff(void *x, void *y)
258 return (pointer_sized_uint_t)x - (pointer_sized_uint_t)y;
261 /* a structure to hold the state of a generation
263 * CAUTION: If you modify this, make sure to touch up the alien
264 * definition in src/code/gc.lisp accordingly. ...or better yes,
265 * deal with the FIXME there...
269 /* the first page that gc_alloc() checks on its next call */
270 page_index_t alloc_start_page;
272 /* the first page that gc_alloc_unboxed() checks on its next call */
273 page_index_t alloc_unboxed_start_page;
275 /* the first page that gc_alloc_large (boxed) considers on its next
276 * call. (Although it always allocates after the boxed_region.) */
277 page_index_t alloc_large_start_page;
279 /* the first page that gc_alloc_large (unboxed) considers on its
280 * next call. (Although it always allocates after the
281 * current_unboxed_region.) */
282 page_index_t alloc_large_unboxed_start_page;
284 /* the bytes allocated to this generation */
285 unsigned long bytes_allocated;
287 /* the number of bytes at which to trigger a GC */
288 unsigned long gc_trigger;
290 /* to calculate a new level for gc_trigger */
291 unsigned long bytes_consed_between_gc;
293 /* the number of GCs since the last raise */
296 /* the number of GCs to run on the generations before raising objects to the
298 int number_of_gcs_before_promotion;
300 /* the cumulative sum of the bytes allocated to this generation. It is
301 * cleared after a GC on this generations, and update before new
302 * objects are added from a GC of a younger generation. Dividing by
303 * the bytes_allocated will give the average age of the memory in
304 * this generation since its last GC. */
305 unsigned long cum_sum_bytes_allocated;
307 /* a minimum average memory age before a GC will occur helps
308 * prevent a GC when a large number of new live objects have been
309 * added, in which case a GC could be a waste of time */
310 double minimum_age_before_gc;
312 /* A linked list of lutex structures in this generation, used for
313 * implementing lutex finalization. */
315 struct lutex *lutexes;
321 /* an array of generation structures. There needs to be one more
322 * generation structure than actual generations as the oldest
323 * generation is temporarily raised then lowered. */
324 struct generation generations[NUM_GENERATIONS];
326 /* the oldest generation that is will currently be GCed by default.
327 * Valid values are: 0, 1, ... HIGHEST_NORMAL_GENERATION
329 * The default of HIGHEST_NORMAL_GENERATION enables GC on all generations.
331 * Setting this to 0 effectively disables the generational nature of
332 * the GC. In some applications generational GC may not be useful
333 * because there are no long-lived objects.
335 * An intermediate value could be handy after moving long-lived data
336 * into an older generation so an unnecessary GC of this long-lived
337 * data can be avoided. */
338 generation_index_t gencgc_oldest_gen_to_gc = HIGHEST_NORMAL_GENERATION;
340 /* The maximum free page in the heap is maintained and used to update
341 * ALLOCATION_POINTER which is used by the room function to limit its
342 * search of the heap. XX Gencgc obviously needs to be better
343 * integrated with the Lisp code. */
344 page_index_t last_free_page;
346 #ifdef LISP_FEATURE_SB_THREAD
347 /* This lock is to prevent multiple threads from simultaneously
348 * allocating new regions which overlap each other. Note that the
349 * majority of GC is single-threaded, but alloc() may be called from
350 * >1 thread at a time and must be thread-safe. This lock must be
351 * seized before all accesses to generations[] or to parts of
352 * page_table[] that other threads may want to see */
353 static pthread_mutex_t free_pages_lock = PTHREAD_MUTEX_INITIALIZER;
354 /* This lock is used to protect non-thread-local allocation. */
355 static pthread_mutex_t allocation_lock = PTHREAD_MUTEX_INITIALIZER;
358 extern unsigned long gencgc_release_granularity;
359 unsigned long gencgc_release_granularity = GENCGC_RELEASE_GRANULARITY;
361 extern unsigned long gencgc_alloc_granularity;
362 unsigned long gencgc_alloc_granularity = GENCGC_ALLOC_GRANULARITY;
366 * miscellaneous heap functions
369 /* Count the number of pages which are write-protected within the
370 * given generation. */
372 count_write_protect_generation_pages(generation_index_t generation)
375 unsigned long count = 0;
377 for (i = 0; i < last_free_page; i++)
378 if (page_allocated_p(i)
379 && (page_table[i].gen == generation)
380 && (page_table[i].write_protected == 1))
385 /* Count the number of pages within the given generation. */
387 count_generation_pages(generation_index_t generation)
392 for (i = 0; i < last_free_page; i++)
393 if (page_allocated_p(i)
394 && (page_table[i].gen == generation))
401 count_dont_move_pages(void)
405 for (i = 0; i < last_free_page; i++) {
406 if (page_allocated_p(i)
407 && (page_table[i].dont_move != 0)) {
415 /* Work through the pages and add up the number of bytes used for the
416 * given generation. */
418 count_generation_bytes_allocated (generation_index_t gen)
421 unsigned long result = 0;
422 for (i = 0; i < last_free_page; i++) {
423 if (page_allocated_p(i)
424 && (page_table[i].gen == gen))
425 result += page_table[i].bytes_used;
430 /* Return the average age of the memory in a generation. */
432 generation_average_age(generation_index_t gen)
434 if (generations[gen].bytes_allocated == 0)
438 ((double)generations[gen].cum_sum_bytes_allocated)
439 / ((double)generations[gen].bytes_allocated);
443 write_generation_stats(FILE *file)
445 generation_index_t i;
447 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
448 #define FPU_STATE_SIZE 27
449 int fpu_state[FPU_STATE_SIZE];
450 #elif defined(LISP_FEATURE_PPC)
451 #define FPU_STATE_SIZE 32
452 long long fpu_state[FPU_STATE_SIZE];
455 /* This code uses the FP instructions which may be set up for Lisp
456 * so they need to be saved and reset for C. */
459 /* Print the heap stats. */
461 " Gen StaPg UbSta LaSta LUbSt Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
463 for (i = 0; i < SCRATCH_GENERATION; i++) {
466 long unboxed_cnt = 0;
467 long large_boxed_cnt = 0;
468 long large_unboxed_cnt = 0;
471 for (j = 0; j < last_free_page; j++)
472 if (page_table[j].gen == i) {
474 /* Count the number of boxed pages within the given
476 if (page_boxed_p(j)) {
477 if (page_table[j].large_object)
482 if(page_table[j].dont_move) pinned_cnt++;
483 /* Count the number of unboxed pages within the given
485 if (page_unboxed_p(j)) {
486 if (page_table[j].large_object)
493 gc_assert(generations[i].bytes_allocated
494 == count_generation_bytes_allocated(i));
496 " %1d: %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %5ld %8ld %5ld %8ld %4ld %3d %7.4f\n",
498 generations[i].alloc_start_page,
499 generations[i].alloc_unboxed_start_page,
500 generations[i].alloc_large_start_page,
501 generations[i].alloc_large_unboxed_start_page,
507 generations[i].bytes_allocated,
508 (npage_bytes(count_generation_pages(i))
509 - generations[i].bytes_allocated),
510 generations[i].gc_trigger,
511 count_write_protect_generation_pages(i),
512 generations[i].num_gc,
513 generation_average_age(i));
515 fprintf(file," Total bytes allocated = %lu\n", bytes_allocated);
516 fprintf(file," Dynamic-space-size bytes = %lu\n", (unsigned long)dynamic_space_size);
518 fpu_restore(fpu_state);
522 write_heap_exhaustion_report(FILE *file, long available, long requested,
523 struct thread *thread)
526 "Heap exhausted during %s: %ld bytes available, %ld requested.\n",
527 gc_active_p ? "garbage collection" : "allocation",
530 write_generation_stats(file);
531 fprintf(file, "GC control variables:\n");
532 fprintf(file, " *GC-INHIBIT* = %s\n *GC-PENDING* = %s\n",
533 SymbolValue(GC_INHIBIT,thread)==NIL ? "false" : "true",
534 (SymbolValue(GC_PENDING, thread) == T) ?
535 "true" : ((SymbolValue(GC_PENDING, thread) == NIL) ?
536 "false" : "in progress"));
537 #ifdef LISP_FEATURE_SB_THREAD
538 fprintf(file, " *STOP-FOR-GC-PENDING* = %s\n",
539 SymbolValue(STOP_FOR_GC_PENDING,thread)==NIL ? "false" : "true");
544 print_generation_stats(void)
546 write_generation_stats(stderr);
549 extern char* gc_logfile;
550 char * gc_logfile = NULL;
553 log_generation_stats(char *logfile, char *header)
556 FILE * log = fopen(logfile, "a");
558 fprintf(log, "%s\n", header);
559 write_generation_stats(log);
562 fprintf(stderr, "Could not open gc logfile: %s\n", logfile);
569 report_heap_exhaustion(long available, long requested, struct thread *th)
572 FILE * log = fopen(gc_logfile, "a");
574 write_heap_exhaustion_report(log, available, requested, th);
577 fprintf(stderr, "Could not open gc logfile: %s\n", gc_logfile);
581 /* Always to stderr as well. */
582 write_heap_exhaustion_report(stderr, available, requested, th);
586 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
587 void fast_bzero(void*, size_t); /* in <arch>-assem.S */
590 /* Zero the pages from START to END (inclusive), but use mmap/munmap instead
591 * if zeroing it ourselves, i.e. in practice give the memory back to the
592 * OS. Generally done after a large GC.
594 void zero_pages_with_mmap(page_index_t start, page_index_t end) {
596 void *addr = page_address(start), *new_addr;
597 size_t length = npage_bytes(1+end-start);
602 gc_assert(length >= gencgc_release_granularity);
603 gc_assert((length % gencgc_release_granularity) == 0);
605 os_invalidate(addr, length);
606 new_addr = os_validate(addr, length);
607 if (new_addr == NULL || new_addr != addr) {
608 lose("remap_free_pages: page moved, 0x%08x ==> 0x%08x",
612 for (i = start; i <= end; i++) {
613 page_table[i].need_to_zero = 0;
617 /* Zero the pages from START to END (inclusive). Generally done just after
618 * a new region has been allocated.
621 zero_pages(page_index_t start, page_index_t end) {
625 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
626 fast_bzero(page_address(start), npage_bytes(1+end-start));
628 bzero(page_address(start), npage_bytes(1+end-start));
633 /* Zero the pages from START to END (inclusive), except for those
634 * pages that are known to already zeroed. Mark all pages in the
635 * ranges as non-zeroed.
638 zero_dirty_pages(page_index_t start, page_index_t end) {
641 for (i = start; i <= end; i++) {
642 if (!page_table[i].need_to_zero) continue;
643 for (j = i+1; (j <= end) && (page_table[j].need_to_zero); j++);
648 for (i = start; i <= end; i++) {
649 page_table[i].need_to_zero = 1;
655 * To support quick and inline allocation, regions of memory can be
656 * allocated and then allocated from with just a free pointer and a
657 * check against an end address.
659 * Since objects can be allocated to spaces with different properties
660 * e.g. boxed/unboxed, generation, ages; there may need to be many
661 * allocation regions.
663 * Each allocation region may start within a partly used page. Many
664 * features of memory use are noted on a page wise basis, e.g. the
665 * generation; so if a region starts within an existing allocated page
666 * it must be consistent with this page.
668 * During the scavenging of the newspace, objects will be transported
669 * into an allocation region, and pointers updated to point to this
670 * allocation region. It is possible that these pointers will be
671 * scavenged again before the allocation region is closed, e.g. due to
672 * trans_list which jumps all over the place to cleanup the list. It
673 * is important to be able to determine properties of all objects
674 * pointed to when scavenging, e.g to detect pointers to the oldspace.
675 * Thus it's important that the allocation regions have the correct
676 * properties set when allocated, and not just set when closed. The
677 * region allocation routines return regions with the specified
678 * properties, and grab all the pages, setting their properties
679 * appropriately, except that the amount used is not known.
681 * These regions are used to support quicker allocation using just a
682 * free pointer. The actual space used by the region is not reflected
683 * in the pages tables until it is closed. It can't be scavenged until
686 * When finished with the region it should be closed, which will
687 * update the page tables for the actual space used returning unused
688 * space. Further it may be noted in the new regions which is
689 * necessary when scavenging the newspace.
691 * Large objects may be allocated directly without an allocation
692 * region, the page tables are updated immediately.
694 * Unboxed objects don't contain pointers to other objects and so
695 * don't need scavenging. Further they can't contain pointers to
696 * younger generations so WP is not needed. By allocating pages to
697 * unboxed objects the whole page never needs scavenging or
698 * write-protecting. */
700 /* We are only using two regions at present. Both are for the current
701 * newspace generation. */
702 struct alloc_region boxed_region;
703 struct alloc_region unboxed_region;
705 /* The generation currently being allocated to. */
706 static generation_index_t gc_alloc_generation;
708 static inline page_index_t
709 generation_alloc_start_page(generation_index_t generation, int page_type_flag, int large)
712 if (UNBOXED_PAGE_FLAG == page_type_flag) {
713 return generations[generation].alloc_large_unboxed_start_page;
714 } else if (BOXED_PAGE_FLAG & page_type_flag) {
715 /* Both code and data. */
716 return generations[generation].alloc_large_start_page;
718 lose("bad page type flag: %d", page_type_flag);
721 if (UNBOXED_PAGE_FLAG == page_type_flag) {
722 return generations[generation].alloc_unboxed_start_page;
723 } else if (BOXED_PAGE_FLAG & page_type_flag) {
724 /* Both code and data. */
725 return generations[generation].alloc_start_page;
727 lose("bad page_type_flag: %d", page_type_flag);
733 set_generation_alloc_start_page(generation_index_t generation, int page_type_flag, int large,
737 if (UNBOXED_PAGE_FLAG == page_type_flag) {
738 generations[generation].alloc_large_unboxed_start_page = page;
739 } else if (BOXED_PAGE_FLAG & page_type_flag) {
740 /* Both code and data. */
741 generations[generation].alloc_large_start_page = page;
743 lose("bad page type flag: %d", page_type_flag);
746 if (UNBOXED_PAGE_FLAG == page_type_flag) {
747 generations[generation].alloc_unboxed_start_page = page;
748 } else if (BOXED_PAGE_FLAG & page_type_flag) {
749 /* Both code and data. */
750 generations[generation].alloc_start_page = page;
752 lose("bad page type flag: %d", page_type_flag);
757 /* Find a new region with room for at least the given number of bytes.
759 * It starts looking at the current generation's alloc_start_page. So
760 * may pick up from the previous region if there is enough space. This
761 * keeps the allocation contiguous when scavenging the newspace.
763 * The alloc_region should have been closed by a call to
764 * gc_alloc_update_page_tables(), and will thus be in an empty state.
766 * To assist the scavenging functions write-protected pages are not
767 * used. Free pages should not be write-protected.
769 * It is critical to the conservative GC that the start of regions be
770 * known. To help achieve this only small regions are allocated at a
773 * During scavenging, pointers may be found to within the current
774 * region and the page generation must be set so that pointers to the
775 * from space can be recognized. Therefore the generation of pages in
776 * the region are set to gc_alloc_generation. To prevent another
777 * allocation call using the same pages, all the pages in the region
778 * are allocated, although they will initially be empty.
781 gc_alloc_new_region(long nbytes, int page_type_flag, struct alloc_region *alloc_region)
783 page_index_t first_page;
784 page_index_t last_page;
785 unsigned long bytes_found;
791 "/alloc_new_region for %d bytes from gen %d\n",
792 nbytes, gc_alloc_generation));
795 /* Check that the region is in a reset state. */
796 gc_assert((alloc_region->first_page == 0)
797 && (alloc_region->last_page == -1)
798 && (alloc_region->free_pointer == alloc_region->end_addr));
799 ret = thread_mutex_lock(&free_pages_lock);
801 first_page = generation_alloc_start_page(gc_alloc_generation, page_type_flag, 0);
802 last_page=gc_find_freeish_pages(&first_page, nbytes, page_type_flag);
803 bytes_found=(GENCGC_CARD_BYTES - page_table[first_page].bytes_used)
804 + npage_bytes(last_page-first_page);
806 /* Set up the alloc_region. */
807 alloc_region->first_page = first_page;
808 alloc_region->last_page = last_page;
809 alloc_region->start_addr = page_table[first_page].bytes_used
810 + page_address(first_page);
811 alloc_region->free_pointer = alloc_region->start_addr;
812 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
814 /* Set up the pages. */
816 /* The first page may have already been in use. */
817 if (page_table[first_page].bytes_used == 0) {
818 page_table[first_page].allocated = page_type_flag;
819 page_table[first_page].gen = gc_alloc_generation;
820 page_table[first_page].large_object = 0;
821 page_table[first_page].region_start_offset = 0;
824 gc_assert(page_table[first_page].allocated == page_type_flag);
825 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
827 gc_assert(page_table[first_page].gen == gc_alloc_generation);
828 gc_assert(page_table[first_page].large_object == 0);
830 for (i = first_page+1; i <= last_page; i++) {
831 page_table[i].allocated = page_type_flag;
832 page_table[i].gen = gc_alloc_generation;
833 page_table[i].large_object = 0;
834 /* This may not be necessary for unboxed regions (think it was
836 page_table[i].region_start_offset =
837 void_diff(page_address(i),alloc_region->start_addr);
838 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
840 /* Bump up last_free_page. */
841 if (last_page+1 > last_free_page) {
842 last_free_page = last_page+1;
843 /* do we only want to call this on special occasions? like for
845 set_alloc_pointer((lispobj)page_address(last_free_page));
847 ret = thread_mutex_unlock(&free_pages_lock);
850 #ifdef READ_PROTECT_FREE_PAGES
851 os_protect(page_address(first_page),
852 npage_bytes(1+last_page-first_page),
856 /* If the first page was only partial, don't check whether it's
857 * zeroed (it won't be) and don't zero it (since the parts that
858 * we're interested in are guaranteed to be zeroed).
860 if (page_table[first_page].bytes_used) {
864 zero_dirty_pages(first_page, last_page);
866 /* we can do this after releasing free_pages_lock */
867 if (gencgc_zero_check) {
869 for (p = (long *)alloc_region->start_addr;
870 p < (long *)alloc_region->end_addr; p++) {
872 /* KLUDGE: It would be nice to use %lx and explicit casts
873 * (long) in code like this, so that it is less likely to
874 * break randomly when running on a machine with different
875 * word sizes. -- WHN 19991129 */
876 lose("The new region at %x is not zero (start=%p, end=%p).\n",
877 p, alloc_region->start_addr, alloc_region->end_addr);
883 /* If the record_new_objects flag is 2 then all new regions created
886 * If it's 1 then then it is only recorded if the first page of the
887 * current region is <= new_areas_ignore_page. This helps avoid
888 * unnecessary recording when doing full scavenge pass.
890 * The new_object structure holds the page, byte offset, and size of
891 * new regions of objects. Each new area is placed in the array of
892 * these structures pointer to by new_areas. new_areas_index holds the
893 * offset into new_areas.
895 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
896 * later code must detect this and handle it, probably by doing a full
897 * scavenge of a generation. */
898 #define NUM_NEW_AREAS 512
899 static int record_new_objects = 0;
900 static page_index_t new_areas_ignore_page;
906 static struct new_area (*new_areas)[];
907 static long new_areas_index;
910 /* Add a new area to new_areas. */
912 add_new_area(page_index_t first_page, size_t offset, size_t size)
914 unsigned long new_area_start,c;
917 /* Ignore if full. */
918 if (new_areas_index >= NUM_NEW_AREAS)
921 switch (record_new_objects) {
925 if (first_page > new_areas_ignore_page)
934 new_area_start = npage_bytes(first_page) + offset;
936 /* Search backwards for a prior area that this follows from. If
937 found this will save adding a new area. */
938 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
939 unsigned long area_end =
940 npage_bytes((*new_areas)[i].page)
941 + (*new_areas)[i].offset
942 + (*new_areas)[i].size;
944 "/add_new_area S1 %d %d %d %d\n",
945 i, c, new_area_start, area_end));*/
946 if (new_area_start == area_end) {
948 "/adding to [%d] %d %d %d with %d %d %d:\n",
950 (*new_areas)[i].page,
951 (*new_areas)[i].offset,
952 (*new_areas)[i].size,
956 (*new_areas)[i].size += size;
961 (*new_areas)[new_areas_index].page = first_page;
962 (*new_areas)[new_areas_index].offset = offset;
963 (*new_areas)[new_areas_index].size = size;
965 "/new_area %d page %d offset %d size %d\n",
966 new_areas_index, first_page, offset, size));*/
969 /* Note the max new_areas used. */
970 if (new_areas_index > max_new_areas)
971 max_new_areas = new_areas_index;
974 /* Update the tables for the alloc_region. The region may be added to
977 * When done the alloc_region is set up so that the next quick alloc
978 * will fail safely and thus a new region will be allocated. Further
979 * it is safe to try to re-update the page table of this reset
982 gc_alloc_update_page_tables(int page_type_flag, struct alloc_region *alloc_region)
985 page_index_t first_page;
986 page_index_t next_page;
987 unsigned long bytes_used;
988 unsigned long orig_first_page_bytes_used;
989 unsigned long region_size;
990 unsigned long byte_cnt;
994 first_page = alloc_region->first_page;
996 /* Catch an unused alloc_region. */
997 if ((first_page == 0) && (alloc_region->last_page == -1))
1000 next_page = first_page+1;
1002 ret = thread_mutex_lock(&free_pages_lock);
1003 gc_assert(ret == 0);
1004 if (alloc_region->free_pointer != alloc_region->start_addr) {
1005 /* some bytes were allocated in the region */
1006 orig_first_page_bytes_used = page_table[first_page].bytes_used;
1008 gc_assert(alloc_region->start_addr ==
1009 (page_address(first_page)
1010 + page_table[first_page].bytes_used));
1012 /* All the pages used need to be updated */
1014 /* Update the first page. */
1016 /* If the page was free then set up the gen, and
1017 * region_start_offset. */
1018 if (page_table[first_page].bytes_used == 0)
1019 gc_assert(page_table[first_page].region_start_offset == 0);
1020 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
1022 gc_assert(page_table[first_page].allocated & page_type_flag);
1023 gc_assert(page_table[first_page].gen == gc_alloc_generation);
1024 gc_assert(page_table[first_page].large_object == 0);
1028 /* Calculate the number of bytes used in this page. This is not
1029 * always the number of new bytes, unless it was free. */
1031 if ((bytes_used = void_diff(alloc_region->free_pointer,
1032 page_address(first_page)))
1033 >GENCGC_CARD_BYTES) {
1034 bytes_used = GENCGC_CARD_BYTES;
1037 page_table[first_page].bytes_used = bytes_used;
1038 byte_cnt += bytes_used;
1041 /* All the rest of the pages should be free. We need to set
1042 * their region_start_offset pointer to the start of the
1043 * region, and set the bytes_used. */
1045 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
1046 gc_assert(page_table[next_page].allocated & page_type_flag);
1047 gc_assert(page_table[next_page].bytes_used == 0);
1048 gc_assert(page_table[next_page].gen == gc_alloc_generation);
1049 gc_assert(page_table[next_page].large_object == 0);
1051 gc_assert(page_table[next_page].region_start_offset ==
1052 void_diff(page_address(next_page),
1053 alloc_region->start_addr));
1055 /* Calculate the number of bytes used in this page. */
1057 if ((bytes_used = void_diff(alloc_region->free_pointer,
1058 page_address(next_page)))>GENCGC_CARD_BYTES) {
1059 bytes_used = GENCGC_CARD_BYTES;
1062 page_table[next_page].bytes_used = bytes_used;
1063 byte_cnt += bytes_used;
1068 region_size = void_diff(alloc_region->free_pointer,
1069 alloc_region->start_addr);
1070 bytes_allocated += region_size;
1071 generations[gc_alloc_generation].bytes_allocated += region_size;
1073 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
1075 /* Set the generations alloc restart page to the last page of
1077 set_generation_alloc_start_page(gc_alloc_generation, page_type_flag, 0, next_page-1);
1079 /* Add the region to the new_areas if requested. */
1080 if (BOXED_PAGE_FLAG & page_type_flag)
1081 add_new_area(first_page,orig_first_page_bytes_used, region_size);
1085 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
1087 gc_alloc_generation));
1090 /* There are no bytes allocated. Unallocate the first_page if
1091 * there are 0 bytes_used. */
1092 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
1093 if (page_table[first_page].bytes_used == 0)
1094 page_table[first_page].allocated = FREE_PAGE_FLAG;
1097 /* Unallocate any unused pages. */
1098 while (next_page <= alloc_region->last_page) {
1099 gc_assert(page_table[next_page].bytes_used == 0);
1100 page_table[next_page].allocated = FREE_PAGE_FLAG;
1103 ret = thread_mutex_unlock(&free_pages_lock);
1104 gc_assert(ret == 0);
1106 /* alloc_region is per-thread, we're ok to do this unlocked */
1107 gc_set_region_empty(alloc_region);
1110 static inline void *gc_quick_alloc(long nbytes);
1112 /* Allocate a possibly large object. */
1114 gc_alloc_large(long nbytes, int page_type_flag, struct alloc_region *alloc_region)
1116 page_index_t first_page;
1117 page_index_t last_page;
1118 int orig_first_page_bytes_used;
1121 unsigned long bytes_used;
1122 page_index_t next_page;
1125 ret = thread_mutex_lock(&free_pages_lock);
1126 gc_assert(ret == 0);
1128 first_page = generation_alloc_start_page(gc_alloc_generation, page_type_flag, 1);
1129 if (first_page <= alloc_region->last_page) {
1130 first_page = alloc_region->last_page+1;
1133 last_page=gc_find_freeish_pages(&first_page,nbytes, page_type_flag);
1135 gc_assert(first_page > alloc_region->last_page);
1137 set_generation_alloc_start_page(gc_alloc_generation, page_type_flag, 1, last_page);
1139 /* Set up the pages. */
1140 orig_first_page_bytes_used = page_table[first_page].bytes_used;
1142 /* If the first page was free then set up the gen, and
1143 * region_start_offset. */
1144 if (page_table[first_page].bytes_used == 0) {
1145 page_table[first_page].allocated = page_type_flag;
1146 page_table[first_page].gen = gc_alloc_generation;
1147 page_table[first_page].region_start_offset = 0;
1148 page_table[first_page].large_object = 1;
1151 gc_assert(page_table[first_page].allocated == page_type_flag);
1152 gc_assert(page_table[first_page].gen == gc_alloc_generation);
1153 gc_assert(page_table[first_page].large_object == 1);
1157 /* Calc. the number of bytes used in this page. This is not
1158 * always the number of new bytes, unless it was free. */
1160 if ((bytes_used = nbytes+orig_first_page_bytes_used) > GENCGC_CARD_BYTES) {
1161 bytes_used = GENCGC_CARD_BYTES;
1164 page_table[first_page].bytes_used = bytes_used;
1165 byte_cnt += bytes_used;
1167 next_page = first_page+1;
1169 /* All the rest of the pages should be free. We need to set their
1170 * region_start_offset pointer to the start of the region, and set
1171 * the bytes_used. */
1173 gc_assert(page_free_p(next_page));
1174 gc_assert(page_table[next_page].bytes_used == 0);
1175 page_table[next_page].allocated = page_type_flag;
1176 page_table[next_page].gen = gc_alloc_generation;
1177 page_table[next_page].large_object = 1;
1179 page_table[next_page].region_start_offset =
1180 npage_bytes(next_page-first_page) - orig_first_page_bytes_used;
1182 /* Calculate the number of bytes used in this page. */
1184 bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt;
1185 if (bytes_used > GENCGC_CARD_BYTES) {
1186 bytes_used = GENCGC_CARD_BYTES;
1189 page_table[next_page].bytes_used = bytes_used;
1190 page_table[next_page].write_protected=0;
1191 page_table[next_page].dont_move=0;
1192 byte_cnt += bytes_used;
1196 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
1198 bytes_allocated += nbytes;
1199 generations[gc_alloc_generation].bytes_allocated += nbytes;
1201 /* Add the region to the new_areas if requested. */
1202 if (BOXED_PAGE_FLAG & page_type_flag)
1203 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
1205 /* Bump up last_free_page */
1206 if (last_page+1 > last_free_page) {
1207 last_free_page = last_page+1;
1208 set_alloc_pointer((lispobj)(page_address(last_free_page)));
1210 ret = thread_mutex_unlock(&free_pages_lock);
1211 gc_assert(ret == 0);
1213 #ifdef READ_PROTECT_FREE_PAGES
1214 os_protect(page_address(first_page),
1215 npage_bytes(1+last_page-first_page),
1219 zero_dirty_pages(first_page, last_page);
1221 return page_address(first_page);
1224 static page_index_t gencgc_alloc_start_page = -1;
1227 gc_heap_exhausted_error_or_lose (long available, long requested)
1229 struct thread *thread = arch_os_get_current_thread();
1230 /* Write basic information before doing anything else: if we don't
1231 * call to lisp this is a must, and even if we do there is always
1232 * the danger that we bounce back here before the error has been
1233 * handled, or indeed even printed.
1235 report_heap_exhaustion(available, requested, thread);
1236 if (gc_active_p || (available == 0)) {
1237 /* If we are in GC, or totally out of memory there is no way
1238 * to sanely transfer control to the lisp-side of things.
1240 lose("Heap exhausted, game over.");
1243 /* FIXME: assert free_pages_lock held */
1244 (void)thread_mutex_unlock(&free_pages_lock);
1245 gc_assert(get_pseudo_atomic_atomic(thread));
1246 clear_pseudo_atomic_atomic(thread);
1247 if (get_pseudo_atomic_interrupted(thread))
1248 do_pending_interrupt();
1249 /* Another issue is that signalling HEAP-EXHAUSTED error leads
1250 * to running user code at arbitrary places, even in a
1251 * WITHOUT-INTERRUPTS which may lead to a deadlock without
1252 * running out of the heap. So at this point all bets are
1254 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
1255 corruption_warning_and_maybe_lose
1256 ("Signalling HEAP-EXHAUSTED in a WITHOUT-INTERRUPTS.");
1257 funcall2(StaticSymbolFunction(HEAP_EXHAUSTED_ERROR),
1258 alloc_number(available), alloc_number(requested));
1259 lose("HEAP-EXHAUSTED-ERROR fell through");
1264 gc_find_freeish_pages(page_index_t *restart_page_ptr, long nbytes,
1267 page_index_t first_page, last_page;
1268 page_index_t restart_page = *restart_page_ptr;
1269 long nbytes_goal = nbytes;
1270 long bytes_found = 0;
1271 long most_bytes_found = 0;
1272 page_index_t most_bytes_found_from, most_bytes_found_to;
1273 int small_object = nbytes < GENCGC_CARD_BYTES;
1274 /* FIXME: assert(free_pages_lock is held); */
1276 if (nbytes_goal < gencgc_alloc_granularity)
1277 nbytes_goal = gencgc_alloc_granularity;
1279 /* Toggled by gc_and_save for heap compaction, normally -1. */
1280 if (gencgc_alloc_start_page != -1) {
1281 restart_page = gencgc_alloc_start_page;
1284 gc_assert(nbytes>=0);
1285 /* Search for a page with at least nbytes of space. We prefer
1286 * not to split small objects on multiple pages, to reduce the
1287 * number of contiguous allocation regions spaning multiple
1288 * pages: this helps avoid excessive conservativism.
1290 * For other objects, we guarantee that they start on their own
1293 first_page = restart_page;
1294 while (first_page < page_table_pages) {
1296 if (page_free_p(first_page)) {
1297 gc_assert(0 == page_table[first_page].bytes_used);
1298 bytes_found = GENCGC_CARD_BYTES;
1299 } else if (small_object &&
1300 (page_table[first_page].allocated == page_type_flag) &&
1301 (page_table[first_page].large_object == 0) &&
1302 (page_table[first_page].gen == gc_alloc_generation) &&
1303 (page_table[first_page].write_protected == 0) &&
1304 (page_table[first_page].dont_move == 0)) {
1305 bytes_found = GENCGC_CARD_BYTES - page_table[first_page].bytes_used;
1306 if (bytes_found < nbytes) {
1307 if (bytes_found > most_bytes_found)
1308 most_bytes_found = bytes_found;
1317 gc_assert(page_table[first_page].write_protected == 0);
1318 for (last_page = first_page+1;
1319 ((last_page < page_table_pages) &&
1320 page_free_p(last_page) &&
1321 (bytes_found < nbytes_goal));
1323 bytes_found += GENCGC_CARD_BYTES;
1324 gc_assert(0 == page_table[last_page].bytes_used);
1325 gc_assert(0 == page_table[last_page].write_protected);
1328 if (bytes_found > most_bytes_found) {
1329 most_bytes_found = bytes_found;
1330 most_bytes_found_from = first_page;
1331 most_bytes_found_to = last_page;
1333 if (bytes_found >= nbytes_goal)
1336 first_page = last_page;
1339 bytes_found = most_bytes_found;
1340 restart_page = first_page + 1;
1342 /* Check for a failure */
1343 if (bytes_found < nbytes) {
1344 gc_assert(restart_page >= page_table_pages);
1345 gc_heap_exhausted_error_or_lose(most_bytes_found, nbytes);
1348 *restart_page_ptr = most_bytes_found_from;
1349 return most_bytes_found_to-1;
1352 /* Allocate bytes. All the rest of the special-purpose allocation
1353 * functions will eventually call this */
1356 gc_alloc_with_region(long nbytes,int page_type_flag, struct alloc_region *my_region,
1359 void *new_free_pointer;
1361 if (nbytes>=large_object_size)
1362 return gc_alloc_large(nbytes, page_type_flag, my_region);
1364 /* Check whether there is room in the current alloc region. */
1365 new_free_pointer = my_region->free_pointer + nbytes;
1367 /* fprintf(stderr, "alloc %d bytes from %p to %p\n", nbytes,
1368 my_region->free_pointer, new_free_pointer); */
1370 if (new_free_pointer <= my_region->end_addr) {
1371 /* If so then allocate from the current alloc region. */
1372 void *new_obj = my_region->free_pointer;
1373 my_region->free_pointer = new_free_pointer;
1375 /* Unless a `quick' alloc was requested, check whether the
1376 alloc region is almost empty. */
1378 void_diff(my_region->end_addr,my_region->free_pointer) <= 32) {
1379 /* If so, finished with the current region. */
1380 gc_alloc_update_page_tables(page_type_flag, my_region);
1381 /* Set up a new region. */
1382 gc_alloc_new_region(32 /*bytes*/, page_type_flag, my_region);
1385 return((void *)new_obj);
1388 /* Else not enough free space in the current region: retry with a
1391 gc_alloc_update_page_tables(page_type_flag, my_region);
1392 gc_alloc_new_region(nbytes, page_type_flag, my_region);
1393 return gc_alloc_with_region(nbytes, page_type_flag, my_region,0);
1396 /* these are only used during GC: all allocation from the mutator calls
1397 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1400 static inline void *
1401 gc_quick_alloc(long nbytes)
1403 return gc_general_alloc(nbytes, BOXED_PAGE_FLAG, ALLOC_QUICK);
1406 static inline void *
1407 gc_quick_alloc_large(long nbytes)
1409 return gc_general_alloc(nbytes, BOXED_PAGE_FLAG ,ALLOC_QUICK);
1412 static inline void *
1413 gc_alloc_unboxed(long nbytes)
1415 return gc_general_alloc(nbytes, UNBOXED_PAGE_FLAG, 0);
1418 static inline void *
1419 gc_quick_alloc_unboxed(long nbytes)
1421 return gc_general_alloc(nbytes, UNBOXED_PAGE_FLAG, ALLOC_QUICK);
1424 static inline void *
1425 gc_quick_alloc_large_unboxed(long nbytes)
1427 return gc_general_alloc(nbytes, UNBOXED_PAGE_FLAG, ALLOC_QUICK);
1431 /* Copy a large boxed object. If the object is in a large object
1432 * region then it is simply promoted, else it is copied. If it's large
1433 * enough then it's copied to a large object region.
1435 * Vectors may have shrunk. If the object is not copied the space
1436 * needs to be reclaimed, and the page_tables corrected. */
1438 copy_large_object(lispobj object, long nwords)
1442 page_index_t first_page;
1444 gc_assert(is_lisp_pointer(object));
1445 gc_assert(from_space_p(object));
1446 gc_assert((nwords & 0x01) == 0);
1449 /* Check whether it's in a large object region. */
1450 first_page = find_page_index((void *)object);
1451 gc_assert(first_page >= 0);
1453 if (page_table[first_page].large_object) {
1455 /* Promote the object. */
1457 unsigned long remaining_bytes;
1458 page_index_t next_page;
1459 unsigned long bytes_freed;
1460 unsigned long old_bytes_used;
1462 /* Note: Any page write-protection must be removed, else a
1463 * later scavenge_newspace may incorrectly not scavenge these
1464 * pages. This would not be necessary if they are added to the
1465 * new areas, but let's do it for them all (they'll probably
1466 * be written anyway?). */
1468 gc_assert(page_table[first_page].region_start_offset == 0);
1470 next_page = first_page;
1471 remaining_bytes = nwords*N_WORD_BYTES;
1472 while (remaining_bytes > GENCGC_CARD_BYTES) {
1473 gc_assert(page_table[next_page].gen == from_space);
1474 gc_assert(page_boxed_p(next_page));
1475 gc_assert(page_table[next_page].large_object);
1476 gc_assert(page_table[next_page].region_start_offset ==
1477 npage_bytes(next_page-first_page));
1478 gc_assert(page_table[next_page].bytes_used == GENCGC_CARD_BYTES);
1479 /* Should have been unprotected by unprotect_oldspace(). */
1480 gc_assert(page_table[next_page].write_protected == 0);
1482 page_table[next_page].gen = new_space;
1484 remaining_bytes -= GENCGC_CARD_BYTES;
1488 /* Now only one page remains, but the object may have shrunk
1489 * so there may be more unused pages which will be freed. */
1491 /* The object may have shrunk but shouldn't have grown. */
1492 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1494 page_table[next_page].gen = new_space;
1495 gc_assert(page_boxed_p(next_page));
1497 /* Adjust the bytes_used. */
1498 old_bytes_used = page_table[next_page].bytes_used;
1499 page_table[next_page].bytes_used = remaining_bytes;
1501 bytes_freed = old_bytes_used - remaining_bytes;
1503 /* Free any remaining pages; needs care. */
1505 while ((old_bytes_used == GENCGC_CARD_BYTES) &&
1506 (page_table[next_page].gen == from_space) &&
1507 page_boxed_p(next_page) &&
1508 page_table[next_page].large_object &&
1509 (page_table[next_page].region_start_offset ==
1510 npage_bytes(next_page - first_page))) {
1511 /* Checks out OK, free the page. Don't need to bother zeroing
1512 * pages as this should have been done before shrinking the
1513 * object. These pages shouldn't be write-protected as they
1514 * should be zero filled. */
1515 gc_assert(page_table[next_page].write_protected == 0);
1517 old_bytes_used = page_table[next_page].bytes_used;
1518 page_table[next_page].allocated = FREE_PAGE_FLAG;
1519 page_table[next_page].bytes_used = 0;
1520 bytes_freed += old_bytes_used;
1524 generations[from_space].bytes_allocated -= N_WORD_BYTES*nwords
1526 generations[new_space].bytes_allocated += N_WORD_BYTES*nwords;
1527 bytes_allocated -= bytes_freed;
1529 /* Add the region to the new_areas if requested. */
1530 add_new_area(first_page,0,nwords*N_WORD_BYTES);
1534 /* Get tag of object. */
1535 tag = lowtag_of(object);
1537 /* Allocate space. */
1538 new = gc_quick_alloc_large(nwords*N_WORD_BYTES);
1540 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1542 /* Return Lisp pointer of new object. */
1543 return ((lispobj) new) | tag;
1547 /* to copy unboxed objects */
1549 copy_unboxed_object(lispobj object, long nwords)
1554 gc_assert(is_lisp_pointer(object));
1555 gc_assert(from_space_p(object));
1556 gc_assert((nwords & 0x01) == 0);
1558 /* Get tag of object. */
1559 tag = lowtag_of(object);
1561 /* Allocate space. */
1562 new = gc_quick_alloc_unboxed(nwords*N_WORD_BYTES);
1564 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1566 /* Return Lisp pointer of new object. */
1567 return ((lispobj) new) | tag;
1570 /* to copy large unboxed objects
1572 * If the object is in a large object region then it is simply
1573 * promoted, else it is copied. If it's large enough then it's copied
1574 * to a large object region.
1576 * Bignums and vectors may have shrunk. If the object is not copied
1577 * the space needs to be reclaimed, and the page_tables corrected.
1579 * KLUDGE: There's a lot of cut-and-paste duplication between this
1580 * function and copy_large_object(..). -- WHN 20000619 */
1582 copy_large_unboxed_object(lispobj object, long nwords)
1586 page_index_t first_page;
1588 gc_assert(is_lisp_pointer(object));
1589 gc_assert(from_space_p(object));
1590 gc_assert((nwords & 0x01) == 0);
1592 if ((nwords > 1024*1024) && gencgc_verbose) {
1593 FSHOW((stderr, "/copy_large_unboxed_object: %d bytes\n",
1594 nwords*N_WORD_BYTES));
1597 /* Check whether it's a large object. */
1598 first_page = find_page_index((void *)object);
1599 gc_assert(first_page >= 0);
1601 if (page_table[first_page].large_object) {
1602 /* Promote the object. Note: Unboxed objects may have been
1603 * allocated to a BOXED region so it may be necessary to
1604 * change the region to UNBOXED. */
1605 unsigned long remaining_bytes;
1606 page_index_t next_page;
1607 unsigned long bytes_freed;
1608 unsigned long old_bytes_used;
1610 gc_assert(page_table[first_page].region_start_offset == 0);
1612 next_page = first_page;
1613 remaining_bytes = nwords*N_WORD_BYTES;
1614 while (remaining_bytes > GENCGC_CARD_BYTES) {
1615 gc_assert(page_table[next_page].gen == from_space);
1616 gc_assert(page_allocated_no_region_p(next_page));
1617 gc_assert(page_table[next_page].large_object);
1618 gc_assert(page_table[next_page].region_start_offset ==
1619 npage_bytes(next_page-first_page));
1620 gc_assert(page_table[next_page].bytes_used == GENCGC_CARD_BYTES);
1622 page_table[next_page].gen = new_space;
1623 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1624 remaining_bytes -= GENCGC_CARD_BYTES;
1628 /* Now only one page remains, but the object may have shrunk so
1629 * there may be more unused pages which will be freed. */
1631 /* Object may have shrunk but shouldn't have grown - check. */
1632 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1634 page_table[next_page].gen = new_space;
1635 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1637 /* Adjust the bytes_used. */
1638 old_bytes_used = page_table[next_page].bytes_used;
1639 page_table[next_page].bytes_used = remaining_bytes;
1641 bytes_freed = old_bytes_used - remaining_bytes;
1643 /* Free any remaining pages; needs care. */
1645 while ((old_bytes_used == GENCGC_CARD_BYTES) &&
1646 (page_table[next_page].gen == from_space) &&
1647 page_allocated_no_region_p(next_page) &&
1648 page_table[next_page].large_object &&
1649 (page_table[next_page].region_start_offset ==
1650 npage_bytes(next_page - first_page))) {
1651 /* Checks out OK, free the page. Don't need to both zeroing
1652 * pages as this should have been done before shrinking the
1653 * object. These pages shouldn't be write-protected, even if
1654 * boxed they should be zero filled. */
1655 gc_assert(page_table[next_page].write_protected == 0);
1657 old_bytes_used = page_table[next_page].bytes_used;
1658 page_table[next_page].allocated = FREE_PAGE_FLAG;
1659 page_table[next_page].bytes_used = 0;
1660 bytes_freed += old_bytes_used;
1664 if ((bytes_freed > 0) && gencgc_verbose) {
1666 "/copy_large_unboxed bytes_freed=%d\n",
1670 generations[from_space].bytes_allocated -=
1671 nwords*N_WORD_BYTES + bytes_freed;
1672 generations[new_space].bytes_allocated += nwords*N_WORD_BYTES;
1673 bytes_allocated -= bytes_freed;
1678 /* Get tag of object. */
1679 tag = lowtag_of(object);
1681 /* Allocate space. */
1682 new = gc_quick_alloc_large_unboxed(nwords*N_WORD_BYTES);
1684 /* Copy the object. */
1685 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1687 /* Return Lisp pointer of new object. */
1688 return ((lispobj) new) | tag;
1697 * code and code-related objects
1700 static lispobj trans_fun_header(lispobj object);
1701 static lispobj trans_boxed(lispobj object);
1704 /* Scan a x86 compiled code object, looking for possible fixups that
1705 * have been missed after a move.
1707 * Two types of fixups are needed:
1708 * 1. Absolute fixups to within the code object.
1709 * 2. Relative fixups to outside the code object.
1711 * Currently only absolute fixups to the constant vector, or to the
1712 * code area are checked. */
1714 sniff_code_object(struct code *code, unsigned long displacement)
1716 #ifdef LISP_FEATURE_X86
1717 long nheader_words, ncode_words, nwords;
1719 void *constants_start_addr = NULL, *constants_end_addr;
1720 void *code_start_addr, *code_end_addr;
1721 int fixup_found = 0;
1723 if (!check_code_fixups)
1726 FSHOW((stderr, "/sniffing code: %p, %lu\n", code, displacement));
1728 ncode_words = fixnum_value(code->code_size);
1729 nheader_words = HeaderValue(*(lispobj *)code);
1730 nwords = ncode_words + nheader_words;
1732 constants_start_addr = (void *)code + 5*N_WORD_BYTES;
1733 constants_end_addr = (void *)code + nheader_words*N_WORD_BYTES;
1734 code_start_addr = (void *)code + nheader_words*N_WORD_BYTES;
1735 code_end_addr = (void *)code + nwords*N_WORD_BYTES;
1737 /* Work through the unboxed code. */
1738 for (p = code_start_addr; p < code_end_addr; p++) {
1739 void *data = *(void **)p;
1740 unsigned d1 = *((unsigned char *)p - 1);
1741 unsigned d2 = *((unsigned char *)p - 2);
1742 unsigned d3 = *((unsigned char *)p - 3);
1743 unsigned d4 = *((unsigned char *)p - 4);
1745 unsigned d5 = *((unsigned char *)p - 5);
1746 unsigned d6 = *((unsigned char *)p - 6);
1749 /* Check for code references. */
1750 /* Check for a 32 bit word that looks like an absolute
1751 reference to within the code adea of the code object. */
1752 if ((data >= (code_start_addr-displacement))
1753 && (data < (code_end_addr-displacement))) {
1754 /* function header */
1756 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) ==
1758 /* Skip the function header */
1762 /* the case of PUSH imm32 */
1766 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1767 p, d6, d5, d4, d3, d2, d1, data));
1768 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1770 /* the case of MOV [reg-8],imm32 */
1772 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1773 || d2==0x45 || d2==0x46 || d2==0x47)
1777 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1778 p, d6, d5, d4, d3, d2, d1, data));
1779 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1781 /* the case of LEA reg,[disp32] */
1782 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1785 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1786 p, d6, d5, d4, d3, d2, d1, data));
1787 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1791 /* Check for constant references. */
1792 /* Check for a 32 bit word that looks like an absolute
1793 reference to within the constant vector. Constant references
1795 if ((data >= (constants_start_addr-displacement))
1796 && (data < (constants_end_addr-displacement))
1797 && (((unsigned)data & 0x3) == 0)) {
1802 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1803 p, d6, d5, d4, d3, d2, d1, data));
1804 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1807 /* the case of MOV m32,EAX */
1811 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1812 p, d6, d5, d4, d3, d2, d1, data));
1813 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1816 /* the case of CMP m32,imm32 */
1817 if ((d1 == 0x3d) && (d2 == 0x81)) {
1820 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1821 p, d6, d5, d4, d3, d2, d1, data));
1823 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1826 /* Check for a mod=00, r/m=101 byte. */
1827 if ((d1 & 0xc7) == 5) {
1832 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1833 p, d6, d5, d4, d3, d2, d1, data));
1834 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1836 /* the case of CMP reg32,m32 */
1840 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1841 p, d6, d5, d4, d3, d2, d1, data));
1842 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1844 /* the case of MOV m32,reg32 */
1848 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1849 p, d6, d5, d4, d3, d2, d1, data));
1850 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1852 /* the case of MOV reg32,m32 */
1856 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1857 p, d6, d5, d4, d3, d2, d1, data));
1858 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1860 /* the case of LEA reg32,m32 */
1864 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1865 p, d6, d5, d4, d3, d2, d1, data));
1866 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1872 /* If anything was found, print some information on the code
1876 "/compiled code object at %x: header words = %d, code words = %d\n",
1877 code, nheader_words, ncode_words));
1879 "/const start = %x, end = %x\n",
1880 constants_start_addr, constants_end_addr));
1882 "/code start = %x, end = %x\n",
1883 code_start_addr, code_end_addr));
1889 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1891 /* x86-64 uses pc-relative addressing instead of this kludge */
1892 #ifndef LISP_FEATURE_X86_64
1893 long nheader_words, ncode_words, nwords;
1894 void *constants_start_addr, *constants_end_addr;
1895 void *code_start_addr, *code_end_addr;
1896 lispobj fixups = NIL;
1897 unsigned long displacement =
1898 (unsigned long)new_code - (unsigned long)old_code;
1899 struct vector *fixups_vector;
1901 ncode_words = fixnum_value(new_code->code_size);
1902 nheader_words = HeaderValue(*(lispobj *)new_code);
1903 nwords = ncode_words + nheader_words;
1905 "/compiled code object at %x: header words = %d, code words = %d\n",
1906 new_code, nheader_words, ncode_words)); */
1907 constants_start_addr = (void *)new_code + 5*N_WORD_BYTES;
1908 constants_end_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1909 code_start_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1910 code_end_addr = (void *)new_code + nwords*N_WORD_BYTES;
1913 "/const start = %x, end = %x\n",
1914 constants_start_addr,constants_end_addr));
1916 "/code start = %x; end = %x\n",
1917 code_start_addr,code_end_addr));
1920 /* The first constant should be a pointer to the fixups for this
1921 code objects. Check. */
1922 fixups = new_code->constants[0];
1924 /* It will be 0 or the unbound-marker if there are no fixups (as
1925 * will be the case if the code object has been purified, for
1926 * example) and will be an other pointer if it is valid. */
1927 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1928 !is_lisp_pointer(fixups)) {
1929 /* Check for possible errors. */
1930 if (check_code_fixups)
1931 sniff_code_object(new_code, displacement);
1936 fixups_vector = (struct vector *)native_pointer(fixups);
1938 /* Could be pointing to a forwarding pointer. */
1939 /* FIXME is this always in from_space? if so, could replace this code with
1940 * forwarding_pointer_p/forwarding_pointer_value */
1941 if (is_lisp_pointer(fixups) &&
1942 (find_page_index((void*)fixups_vector) != -1) &&
1943 (fixups_vector->header == 0x01)) {
1944 /* If so, then follow it. */
1945 /*SHOW("following pointer to a forwarding pointer");*/
1947 (struct vector *)native_pointer((lispobj)fixups_vector->length);
1950 /*SHOW("got fixups");*/
1952 if (widetag_of(fixups_vector->header) == SIMPLE_ARRAY_WORD_WIDETAG) {
1953 /* Got the fixups for the code block. Now work through the vector,
1954 and apply a fixup at each address. */
1955 long length = fixnum_value(fixups_vector->length);
1957 for (i = 0; i < length; i++) {
1958 unsigned long offset = fixups_vector->data[i];
1959 /* Now check the current value of offset. */
1960 unsigned long old_value =
1961 *(unsigned long *)((unsigned long)code_start_addr + offset);
1963 /* If it's within the old_code object then it must be an
1964 * absolute fixup (relative ones are not saved) */
1965 if ((old_value >= (unsigned long)old_code)
1966 && (old_value < ((unsigned long)old_code
1967 + nwords*N_WORD_BYTES)))
1968 /* So add the dispacement. */
1969 *(unsigned long *)((unsigned long)code_start_addr + offset) =
1970 old_value + displacement;
1972 /* It is outside the old code object so it must be a
1973 * relative fixup (absolute fixups are not saved). So
1974 * subtract the displacement. */
1975 *(unsigned long *)((unsigned long)code_start_addr + offset) =
1976 old_value - displacement;
1979 /* This used to just print a note to stderr, but a bogus fixup seems to
1980 * indicate real heap corruption, so a hard hailure is in order. */
1981 lose("fixup vector %p has a bad widetag: %d\n",
1982 fixups_vector, widetag_of(fixups_vector->header));
1985 /* Check for possible errors. */
1986 if (check_code_fixups) {
1987 sniff_code_object(new_code,displacement);
1994 trans_boxed_large(lispobj object)
1997 unsigned long length;
1999 gc_assert(is_lisp_pointer(object));
2001 header = *((lispobj *) native_pointer(object));
2002 length = HeaderValue(header) + 1;
2003 length = CEILING(length, 2);
2005 return copy_large_object(object, length);
2008 /* Doesn't seem to be used, delete it after the grace period. */
2011 trans_unboxed_large(lispobj object)
2014 unsigned long length;
2016 gc_assert(is_lisp_pointer(object));
2018 header = *((lispobj *) native_pointer(object));
2019 length = HeaderValue(header) + 1;
2020 length = CEILING(length, 2);
2022 return copy_large_unboxed_object(object, length);
2028 * Lutexes. Using the normal finalization machinery for finalizing
2029 * lutexes is tricky, since the finalization depends on working lutexes.
2030 * So we track the lutexes in the GC and finalize them manually.
2033 #if defined(LUTEX_WIDETAG)
2036 * Start tracking LUTEX in the GC, by adding it to the linked list of
2037 * lutexes in the nursery generation. The caller is responsible for
2038 * locking, and GCs must be inhibited until the registration is
2042 gencgc_register_lutex (struct lutex *lutex) {
2043 int index = find_page_index(lutex);
2044 generation_index_t gen;
2047 /* This lutex is in static space, so we don't need to worry about
2053 gen = page_table[index].gen;
2055 gc_assert(gen >= 0);
2056 gc_assert(gen < NUM_GENERATIONS);
2058 head = generations[gen].lutexes;
2065 generations[gen].lutexes = lutex;
2069 * Stop tracking LUTEX in the GC by removing it from the appropriate
2070 * linked lists. This will only be called during GC, so no locking is
2074 gencgc_unregister_lutex (struct lutex *lutex) {
2076 lutex->prev->next = lutex->next;
2078 generations[lutex->gen].lutexes = lutex->next;
2082 lutex->next->prev = lutex->prev;
2091 * Mark all lutexes in generation GEN as not live.
2094 unmark_lutexes (generation_index_t gen) {
2095 struct lutex *lutex = generations[gen].lutexes;
2099 lutex = lutex->next;
2104 * Finalize all lutexes in generation GEN that have not been marked live.
2107 reap_lutexes (generation_index_t gen) {
2108 struct lutex *lutex = generations[gen].lutexes;
2111 struct lutex *next = lutex->next;
2113 lutex_destroy((tagged_lutex_t) lutex);
2114 gencgc_unregister_lutex(lutex);
2121 * Mark LUTEX as live.
2124 mark_lutex (lispobj tagged_lutex) {
2125 struct lutex *lutex = (struct lutex*) native_pointer(tagged_lutex);
2131 * Move all lutexes in generation FROM to generation TO.
2134 move_lutexes (generation_index_t from, generation_index_t to) {
2135 struct lutex *tail = generations[from].lutexes;
2137 /* Nothing to move */
2141 /* Change the generation of the lutexes in FROM. */
2142 while (tail->next) {
2148 /* Link the last lutex in the FROM list to the start of the TO list */
2149 tail->next = generations[to].lutexes;
2151 /* And vice versa */
2152 if (generations[to].lutexes) {
2153 generations[to].lutexes->prev = tail;
2156 /* And update the generations structures to match this */
2157 generations[to].lutexes = generations[from].lutexes;
2158 generations[from].lutexes = NULL;
2162 scav_lutex(lispobj *where, lispobj object)
2164 mark_lutex((lispobj) where);
2166 return CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
2170 trans_lutex(lispobj object)
2172 struct lutex *lutex = (struct lutex *) native_pointer(object);
2174 size_t words = CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
2175 gc_assert(is_lisp_pointer(object));
2176 copied = copy_object(object, words);
2178 /* Update the links, since the lutex moved in memory. */
2180 lutex->next->prev = (struct lutex *) native_pointer(copied);
2184 lutex->prev->next = (struct lutex *) native_pointer(copied);
2186 generations[lutex->gen].lutexes =
2187 (struct lutex *) native_pointer(copied);
2194 size_lutex(lispobj *where)
2196 return CEILING(sizeof(struct lutex)/sizeof(lispobj), 2);
2198 #endif /* LUTEX_WIDETAG */
2205 /* XX This is a hack adapted from cgc.c. These don't work too
2206 * efficiently with the gencgc as a list of the weak pointers is
2207 * maintained within the objects which causes writes to the pages. A
2208 * limited attempt is made to avoid unnecessary writes, but this needs
2210 #define WEAK_POINTER_NWORDS \
2211 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
2214 scav_weak_pointer(lispobj *where, lispobj object)
2216 /* Since we overwrite the 'next' field, we have to make
2217 * sure not to do so for pointers already in the list.
2218 * Instead of searching the list of weak_pointers each
2219 * time, we ensure that next is always NULL when the weak
2220 * pointer isn't in the list, and not NULL otherwise.
2221 * Since we can't use NULL to denote end of list, we
2222 * use a pointer back to the same weak_pointer.
2224 struct weak_pointer * wp = (struct weak_pointer*)where;
2226 if (NULL == wp->next) {
2227 wp->next = weak_pointers;
2229 if (NULL == wp->next)
2233 /* Do not let GC scavenge the value slot of the weak pointer.
2234 * (That is why it is a weak pointer.) */
2236 return WEAK_POINTER_NWORDS;
2241 search_read_only_space(void *pointer)
2243 lispobj *start = (lispobj *) READ_ONLY_SPACE_START;
2244 lispobj *end = (lispobj *) SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
2245 if ((pointer < (void *)start) || (pointer >= (void *)end))
2247 return (gc_search_space(start,
2248 (((lispobj *)pointer)+2)-start,
2249 (lispobj *) pointer));
2253 search_static_space(void *pointer)
2255 lispobj *start = (lispobj *)STATIC_SPACE_START;
2256 lispobj *end = (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
2257 if ((pointer < (void *)start) || (pointer >= (void *)end))
2259 return (gc_search_space(start,
2260 (((lispobj *)pointer)+2)-start,
2261 (lispobj *) pointer));
2264 /* a faster version for searching the dynamic space. This will work even
2265 * if the object is in a current allocation region. */
2267 search_dynamic_space(void *pointer)
2269 page_index_t page_index = find_page_index(pointer);
2272 /* The address may be invalid, so do some checks. */
2273 if ((page_index == -1) || page_free_p(page_index))
2275 start = (lispobj *)page_region_start(page_index);
2276 return (gc_search_space(start,
2277 (((lispobj *)pointer)+2)-start,
2278 (lispobj *)pointer));
2281 /* Helper for valid_lisp_pointer_p and
2282 * possibly_valid_dynamic_space_pointer.
2284 * pointer is the pointer to validate, and start_addr is the address
2285 * of the enclosing object.
2288 looks_like_valid_lisp_pointer_p(lispobj *pointer, lispobj *start_addr)
2290 if (!is_lisp_pointer((lispobj)pointer)) {
2294 /* Check that the object pointed to is consistent with the pointer
2296 switch (lowtag_of((lispobj)pointer)) {
2297 case FUN_POINTER_LOWTAG:
2298 /* Start_addr should be the enclosing code object, or a closure
2300 switch (widetag_of(*start_addr)) {
2301 case CODE_HEADER_WIDETAG:
2302 /* Make sure we actually point to a function in the code object,
2303 * as opposed to a random point there. */
2304 if (SIMPLE_FUN_HEADER_WIDETAG==widetag_of(*(pointer-FUN_POINTER_LOWTAG)))
2308 case CLOSURE_HEADER_WIDETAG:
2309 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2310 if ((unsigned long)pointer !=
2311 ((unsigned long)start_addr+FUN_POINTER_LOWTAG)) {
2312 if (gencgc_verbose) {
2315 pointer, start_addr, *start_addr));
2321 if (gencgc_verbose) {
2324 pointer, start_addr, *start_addr));
2329 case LIST_POINTER_LOWTAG:
2330 if ((unsigned long)pointer !=
2331 ((unsigned long)start_addr+LIST_POINTER_LOWTAG)) {
2332 if (gencgc_verbose) {
2335 pointer, start_addr, *start_addr));
2339 /* Is it plausible cons? */
2340 if ((is_lisp_pointer(start_addr[0]) ||
2341 is_lisp_immediate(start_addr[0])) &&
2342 (is_lisp_pointer(start_addr[1]) ||
2343 is_lisp_immediate(start_addr[1])))
2346 if (gencgc_verbose) {
2349 pointer, start_addr, *start_addr));
2353 case INSTANCE_POINTER_LOWTAG:
2354 if ((unsigned long)pointer !=
2355 ((unsigned long)start_addr+INSTANCE_POINTER_LOWTAG)) {
2356 if (gencgc_verbose) {
2359 pointer, start_addr, *start_addr));
2363 if (widetag_of(start_addr[0]) != INSTANCE_HEADER_WIDETAG) {
2364 if (gencgc_verbose) {
2367 pointer, start_addr, *start_addr));
2372 case OTHER_POINTER_LOWTAG:
2374 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
2375 /* The all-architecture test below is good as far as it goes,
2376 * but an LRA object is similar to a FUN-POINTER: It is
2377 * embedded within a CODE-OBJECT pointed to by start_addr, and
2378 * cannot be found by simply walking the heap, therefore we
2379 * need to check for it. -- AB, 2010-Jun-04 */
2380 if ((widetag_of(start_addr[0]) == CODE_HEADER_WIDETAG)) {
2381 lispobj *potential_lra =
2382 (lispobj *)(((unsigned long)pointer) - OTHER_POINTER_LOWTAG);
2383 if ((widetag_of(potential_lra[0]) == RETURN_PC_HEADER_WIDETAG) &&
2384 ((potential_lra - HeaderValue(potential_lra[0])) == start_addr)) {
2385 return 1; /* It's as good as we can verify. */
2390 if ((unsigned long)pointer !=
2391 ((unsigned long)start_addr+OTHER_POINTER_LOWTAG)) {
2392 if (gencgc_verbose) {
2395 pointer, start_addr, *start_addr));
2399 /* Is it plausible? Not a cons. XXX should check the headers. */
2400 if (is_lisp_pointer(start_addr[0]) || ((start_addr[0] & 3) == 0)) {
2401 if (gencgc_verbose) {
2404 pointer, start_addr, *start_addr));
2408 switch (widetag_of(start_addr[0])) {
2409 case UNBOUND_MARKER_WIDETAG:
2410 case NO_TLS_VALUE_MARKER_WIDETAG:
2411 case CHARACTER_WIDETAG:
2412 #if N_WORD_BITS == 64
2413 case SINGLE_FLOAT_WIDETAG:
2415 if (gencgc_verbose) {
2418 pointer, start_addr, *start_addr));
2422 /* only pointed to by function pointers? */
2423 case CLOSURE_HEADER_WIDETAG:
2424 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2425 if (gencgc_verbose) {
2428 pointer, start_addr, *start_addr));
2432 case INSTANCE_HEADER_WIDETAG:
2433 if (gencgc_verbose) {
2436 pointer, start_addr, *start_addr));
2440 /* the valid other immediate pointer objects */
2441 case SIMPLE_VECTOR_WIDETAG:
2443 case COMPLEX_WIDETAG:
2444 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
2445 case COMPLEX_SINGLE_FLOAT_WIDETAG:
2447 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
2448 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
2450 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
2451 case COMPLEX_LONG_FLOAT_WIDETAG:
2453 case SIMPLE_ARRAY_WIDETAG:
2454 case COMPLEX_BASE_STRING_WIDETAG:
2455 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
2456 case COMPLEX_CHARACTER_STRING_WIDETAG:
2458 case COMPLEX_VECTOR_NIL_WIDETAG:
2459 case COMPLEX_BIT_VECTOR_WIDETAG:
2460 case COMPLEX_VECTOR_WIDETAG:
2461 case COMPLEX_ARRAY_WIDETAG:
2462 case VALUE_CELL_HEADER_WIDETAG:
2463 case SYMBOL_HEADER_WIDETAG:
2465 case CODE_HEADER_WIDETAG:
2466 case BIGNUM_WIDETAG:
2467 #if N_WORD_BITS != 64
2468 case SINGLE_FLOAT_WIDETAG:
2470 case DOUBLE_FLOAT_WIDETAG:
2471 #ifdef LONG_FLOAT_WIDETAG
2472 case LONG_FLOAT_WIDETAG:
2474 case SIMPLE_BASE_STRING_WIDETAG:
2475 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2476 case SIMPLE_CHARACTER_STRING_WIDETAG:
2478 case SIMPLE_BIT_VECTOR_WIDETAG:
2479 case SIMPLE_ARRAY_NIL_WIDETAG:
2480 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2481 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2482 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2483 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2484 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2485 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2486 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2487 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2489 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2490 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2491 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2492 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2494 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2495 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2497 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2498 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2500 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2501 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2503 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2504 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2506 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2507 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2509 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2510 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2512 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2513 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
2515 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2516 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2518 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2519 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2520 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2521 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2523 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2524 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2526 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2527 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2529 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2530 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2533 case WEAK_POINTER_WIDETAG:
2534 #ifdef LUTEX_WIDETAG
2540 if (gencgc_verbose) {
2543 pointer, start_addr, *start_addr));
2549 if (gencgc_verbose) {
2552 pointer, start_addr, *start_addr));
2561 /* Used by the debugger to validate possibly bogus pointers before
2562 * calling MAKE-LISP-OBJ on them.
2564 * FIXME: We would like to make this perfect, because if the debugger
2565 * constructs a reference to a bugs lisp object, and it ends up in a
2566 * location scavenged by the GC all hell breaks loose.
2568 * Whereas possibly_valid_dynamic_space_pointer has to be conservative
2569 * and return true for all valid pointers, this could actually be eager
2570 * and lie about a few pointers without bad results... but that should
2571 * be reflected in the name.
2574 valid_lisp_pointer_p(lispobj *pointer)
2577 if (((start=search_dynamic_space(pointer))!=NULL) ||
2578 ((start=search_static_space(pointer))!=NULL) ||
2579 ((start=search_read_only_space(pointer))!=NULL))
2580 return looks_like_valid_lisp_pointer_p(pointer, start);
2585 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2587 /* Is there any possibility that pointer is a valid Lisp object
2588 * reference, and/or something else (e.g. subroutine call return
2589 * address) which should prevent us from moving the referred-to thing?
2590 * This is called from preserve_pointers() */
2592 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2594 lispobj *start_addr;
2596 /* Find the object start address. */
2597 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2601 return looks_like_valid_lisp_pointer_p(pointer, start_addr);
2604 #endif // defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2606 /* Adjust large bignum and vector objects. This will adjust the
2607 * allocated region if the size has shrunk, and move unboxed objects
2608 * into unboxed pages. The pages are not promoted here, and the
2609 * promoted region is not added to the new_regions; this is really
2610 * only designed to be called from preserve_pointer(). Shouldn't fail
2611 * if this is missed, just may delay the moving of objects to unboxed
2612 * pages, and the freeing of pages. */
2614 maybe_adjust_large_object(lispobj *where)
2616 page_index_t first_page;
2617 page_index_t next_page;
2620 unsigned long remaining_bytes;
2621 unsigned long bytes_freed;
2622 unsigned long old_bytes_used;
2626 /* Check whether it's a vector or bignum object. */
2627 switch (widetag_of(where[0])) {
2628 case SIMPLE_VECTOR_WIDETAG:
2629 boxed = BOXED_PAGE_FLAG;
2631 case BIGNUM_WIDETAG:
2632 case SIMPLE_BASE_STRING_WIDETAG:
2633 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2634 case SIMPLE_CHARACTER_STRING_WIDETAG:
2636 case SIMPLE_BIT_VECTOR_WIDETAG:
2637 case SIMPLE_ARRAY_NIL_WIDETAG:
2638 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2639 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2640 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2641 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2642 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2643 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2644 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
2645 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
2647 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2648 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2649 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
2650 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
2652 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2653 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2655 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2656 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2658 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2659 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2661 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2662 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2664 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
2665 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
2667 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2668 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2670 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
2671 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
2673 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2674 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2676 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2677 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2678 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2679 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2681 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2682 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2684 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2685 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2687 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2688 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2690 boxed = UNBOXED_PAGE_FLAG;
2696 /* Find its current size. */
2697 nwords = (sizetab[widetag_of(where[0])])(where);
2699 first_page = find_page_index((void *)where);
2700 gc_assert(first_page >= 0);
2702 /* Note: Any page write-protection must be removed, else a later
2703 * scavenge_newspace may incorrectly not scavenge these pages.
2704 * This would not be necessary if they are added to the new areas,
2705 * but lets do it for them all (they'll probably be written
2708 gc_assert(page_table[first_page].region_start_offset == 0);
2710 next_page = first_page;
2711 remaining_bytes = nwords*N_WORD_BYTES;
2712 while (remaining_bytes > GENCGC_CARD_BYTES) {
2713 gc_assert(page_table[next_page].gen == from_space);
2714 gc_assert(page_allocated_no_region_p(next_page));
2715 gc_assert(page_table[next_page].large_object);
2716 gc_assert(page_table[next_page].region_start_offset ==
2717 npage_bytes(next_page-first_page));
2718 gc_assert(page_table[next_page].bytes_used == GENCGC_CARD_BYTES);
2720 page_table[next_page].allocated = boxed;
2722 /* Shouldn't be write-protected at this stage. Essential that the
2724 gc_assert(!page_table[next_page].write_protected);
2725 remaining_bytes -= GENCGC_CARD_BYTES;
2729 /* Now only one page remains, but the object may have shrunk so
2730 * there may be more unused pages which will be freed. */
2732 /* Object may have shrunk but shouldn't have grown - check. */
2733 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2735 page_table[next_page].allocated = boxed;
2736 gc_assert(page_table[next_page].allocated ==
2737 page_table[first_page].allocated);
2739 /* Adjust the bytes_used. */
2740 old_bytes_used = page_table[next_page].bytes_used;
2741 page_table[next_page].bytes_used = remaining_bytes;
2743 bytes_freed = old_bytes_used - remaining_bytes;
2745 /* Free any remaining pages; needs care. */
2747 while ((old_bytes_used == GENCGC_CARD_BYTES) &&
2748 (page_table[next_page].gen == from_space) &&
2749 page_allocated_no_region_p(next_page) &&
2750 page_table[next_page].large_object &&
2751 (page_table[next_page].region_start_offset ==
2752 npage_bytes(next_page - first_page))) {
2753 /* It checks out OK, free the page. We don't need to both zeroing
2754 * pages as this should have been done before shrinking the
2755 * object. These pages shouldn't be write protected as they
2756 * should be zero filled. */
2757 gc_assert(page_table[next_page].write_protected == 0);
2759 old_bytes_used = page_table[next_page].bytes_used;
2760 page_table[next_page].allocated = FREE_PAGE_FLAG;
2761 page_table[next_page].bytes_used = 0;
2762 bytes_freed += old_bytes_used;
2766 if ((bytes_freed > 0) && gencgc_verbose) {
2768 "/maybe_adjust_large_object() freed %d\n",
2772 generations[from_space].bytes_allocated -= bytes_freed;
2773 bytes_allocated -= bytes_freed;
2778 /* Take a possible pointer to a Lisp object and mark its page in the
2779 * page_table so that it will not be relocated during a GC.
2781 * This involves locating the page it points to, then backing up to
2782 * the start of its region, then marking all pages dont_move from there
2783 * up to the first page that's not full or has a different generation
2785 * It is assumed that all the page static flags have been cleared at
2786 * the start of a GC.
2788 * It is also assumed that the current gc_alloc() region has been
2789 * flushed and the tables updated. */
2792 preserve_pointer(void *addr)
2794 page_index_t addr_page_index = find_page_index(addr);
2795 page_index_t first_page;
2797 unsigned int region_allocation;
2799 /* quick check 1: Address is quite likely to have been invalid. */
2800 if ((addr_page_index == -1)
2801 || page_free_p(addr_page_index)
2802 || (page_table[addr_page_index].bytes_used == 0)
2803 || (page_table[addr_page_index].gen != from_space)
2804 /* Skip if already marked dont_move. */
2805 || (page_table[addr_page_index].dont_move != 0))
2807 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2808 /* (Now that we know that addr_page_index is in range, it's
2809 * safe to index into page_table[] with it.) */
2810 region_allocation = page_table[addr_page_index].allocated;
2812 /* quick check 2: Check the offset within the page.
2815 if (((unsigned long)addr & (GENCGC_CARD_BYTES - 1)) >
2816 page_table[addr_page_index].bytes_used)
2819 /* Filter out anything which can't be a pointer to a Lisp object
2820 * (or, as a special case which also requires dont_move, a return
2821 * address referring to something in a CodeObject). This is
2822 * expensive but important, since it vastly reduces the
2823 * probability that random garbage will be bogusly interpreted as
2824 * a pointer which prevents a page from moving.
2826 * This only needs to happen on x86oids, where this is used for
2827 * conservative roots. Non-x86oid systems only ever call this
2828 * function on known-valid lisp objects. */
2829 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2830 if (!(code_page_p(addr_page_index)
2831 || (is_lisp_pointer((lispobj)addr) &&
2832 possibly_valid_dynamic_space_pointer(addr))))
2836 /* Find the beginning of the region. Note that there may be
2837 * objects in the region preceding the one that we were passed a
2838 * pointer to: if this is the case, we will write-protect all the
2839 * previous objects' pages too. */
2842 /* I think this'd work just as well, but without the assertions.
2843 * -dan 2004.01.01 */
2844 first_page = find_page_index(page_region_start(addr_page_index))
2846 first_page = addr_page_index;
2847 while (page_table[first_page].region_start_offset != 0) {
2849 /* Do some checks. */
2850 gc_assert(page_table[first_page].bytes_used == GENCGC_CARD_BYTES);
2851 gc_assert(page_table[first_page].gen == from_space);
2852 gc_assert(page_table[first_page].allocated == region_allocation);
2856 /* Adjust any large objects before promotion as they won't be
2857 * copied after promotion. */
2858 if (page_table[first_page].large_object) {
2859 maybe_adjust_large_object(page_address(first_page));
2860 /* If a large object has shrunk then addr may now point to a
2861 * free area in which case it's ignored here. Note it gets
2862 * through the valid pointer test above because the tail looks
2864 if (page_free_p(addr_page_index)
2865 || (page_table[addr_page_index].bytes_used == 0)
2866 /* Check the offset within the page. */
2867 || (((unsigned long)addr & (GENCGC_CARD_BYTES - 1))
2868 > page_table[addr_page_index].bytes_used)) {
2870 "weird? ignore ptr 0x%x to freed area of large object\n",
2874 /* It may have moved to unboxed pages. */
2875 region_allocation = page_table[first_page].allocated;
2878 /* Now work forward until the end of this contiguous area is found,
2879 * marking all pages as dont_move. */
2880 for (i = first_page; ;i++) {
2881 gc_assert(page_table[i].allocated == region_allocation);
2883 /* Mark the page static. */
2884 page_table[i].dont_move = 1;
2886 /* Move the page to the new_space. XX I'd rather not do this
2887 * but the GC logic is not quite able to copy with the static
2888 * pages remaining in the from space. This also requires the
2889 * generation bytes_allocated counters be updated. */
2890 page_table[i].gen = new_space;
2891 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2892 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2894 /* It is essential that the pages are not write protected as
2895 * they may have pointers into the old-space which need
2896 * scavenging. They shouldn't be write protected at this
2898 gc_assert(!page_table[i].write_protected);
2900 /* Check whether this is the last page in this contiguous block.. */
2901 if ((page_table[i].bytes_used < GENCGC_CARD_BYTES)
2902 /* ..or it is CARD_BYTES and is the last in the block */
2904 || (page_table[i+1].bytes_used == 0) /* next page free */
2905 || (page_table[i+1].gen != from_space) /* diff. gen */
2906 || (page_table[i+1].region_start_offset == 0))
2910 /* Check that the page is now static. */
2911 gc_assert(page_table[addr_page_index].dont_move != 0);
2914 /* If the given page is not write-protected, then scan it for pointers
2915 * to younger generations or the top temp. generation, if no
2916 * suspicious pointers are found then the page is write-protected.
2918 * Care is taken to check for pointers to the current gc_alloc()
2919 * region if it is a younger generation or the temp. generation. This
2920 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2921 * the gc_alloc_generation does not need to be checked as this is only
2922 * called from scavenge_generation() when the gc_alloc generation is
2923 * younger, so it just checks if there is a pointer to the current
2926 * We return 1 if the page was write-protected, else 0. */
2928 update_page_write_prot(page_index_t page)
2930 generation_index_t gen = page_table[page].gen;
2933 void **page_addr = (void **)page_address(page);
2934 long num_words = page_table[page].bytes_used / N_WORD_BYTES;
2936 /* Shouldn't be a free page. */
2937 gc_assert(page_allocated_p(page));
2938 gc_assert(page_table[page].bytes_used != 0);
2940 /* Skip if it's already write-protected, pinned, or unboxed */
2941 if (page_table[page].write_protected
2942 /* FIXME: What's the reason for not write-protecting pinned pages? */
2943 || page_table[page].dont_move
2944 || page_unboxed_p(page))
2947 /* Scan the page for pointers to younger generations or the
2948 * top temp. generation. */
2950 for (j = 0; j < num_words; j++) {
2951 void *ptr = *(page_addr+j);
2952 page_index_t index = find_page_index(ptr);
2954 /* Check that it's in the dynamic space */
2956 if (/* Does it point to a younger or the temp. generation? */
2957 (page_allocated_p(index)
2958 && (page_table[index].bytes_used != 0)
2959 && ((page_table[index].gen < gen)
2960 || (page_table[index].gen == SCRATCH_GENERATION)))
2962 /* Or does it point within a current gc_alloc() region? */
2963 || ((boxed_region.start_addr <= ptr)
2964 && (ptr <= boxed_region.free_pointer))
2965 || ((unboxed_region.start_addr <= ptr)
2966 && (ptr <= unboxed_region.free_pointer))) {
2973 /* Write-protect the page. */
2974 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2976 os_protect((void *)page_addr,
2978 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2980 /* Note the page as protected in the page tables. */
2981 page_table[page].write_protected = 1;
2987 /* Scavenge all generations from FROM to TO, inclusive, except for
2988 * new_space which needs special handling, as new objects may be
2989 * added which are not checked here - use scavenge_newspace generation.
2991 * Write-protected pages should not have any pointers to the
2992 * from_space so do need scavenging; thus write-protected pages are
2993 * not always scavenged. There is some code to check that these pages
2994 * are not written; but to check fully the write-protected pages need
2995 * to be scavenged by disabling the code to skip them.
2997 * Under the current scheme when a generation is GCed the younger
2998 * generations will be empty. So, when a generation is being GCed it
2999 * is only necessary to scavenge the older generations for pointers
3000 * not the younger. So a page that does not have pointers to younger
3001 * generations does not need to be scavenged.
3003 * The write-protection can be used to note pages that don't have
3004 * pointers to younger pages. But pages can be written without having
3005 * pointers to younger generations. After the pages are scavenged here
3006 * they can be scanned for pointers to younger generations and if
3007 * there are none the page can be write-protected.
3009 * One complication is when the newspace is the top temp. generation.
3011 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
3012 * that none were written, which they shouldn't be as they should have
3013 * no pointers to younger generations. This breaks down for weak
3014 * pointers as the objects contain a link to the next and are written
3015 * if a weak pointer is scavenged. Still it's a useful check. */
3017 scavenge_generations(generation_index_t from, generation_index_t to)
3024 /* Clear the write_protected_cleared flags on all pages. */
3025 for (i = 0; i < page_table_pages; i++)
3026 page_table[i].write_protected_cleared = 0;
3029 for (i = 0; i < last_free_page; i++) {
3030 generation_index_t generation = page_table[i].gen;
3032 && (page_table[i].bytes_used != 0)
3033 && (generation != new_space)
3034 && (generation >= from)
3035 && (generation <= to)) {
3036 page_index_t last_page,j;
3037 int write_protected=1;
3039 /* This should be the start of a region */
3040 gc_assert(page_table[i].region_start_offset == 0);
3042 /* Now work forward until the end of the region */
3043 for (last_page = i; ; last_page++) {
3045 write_protected && page_table[last_page].write_protected;
3046 if ((page_table[last_page].bytes_used < GENCGC_CARD_BYTES)
3047 /* Or it is CARD_BYTES and is the last in the block */
3048 || (!page_boxed_p(last_page+1))
3049 || (page_table[last_page+1].bytes_used == 0)
3050 || (page_table[last_page+1].gen != generation)
3051 || (page_table[last_page+1].region_start_offset == 0))
3054 if (!write_protected) {
3055 scavenge(page_address(i),
3056 ((unsigned long)(page_table[last_page].bytes_used
3057 + npage_bytes(last_page-i)))
3060 /* Now scan the pages and write protect those that
3061 * don't have pointers to younger generations. */
3062 if (enable_page_protection) {
3063 for (j = i; j <= last_page; j++) {
3064 num_wp += update_page_write_prot(j);
3067 if ((gencgc_verbose > 1) && (num_wp != 0)) {
3069 "/write protected %d pages within generation %d\n",
3070 num_wp, generation));
3078 /* Check that none of the write_protected pages in this generation
3079 * have been written to. */
3080 for (i = 0; i < page_table_pages; i++) {
3081 if (page_allocated_p(i)
3082 && (page_table[i].bytes_used != 0)
3083 && (page_table[i].gen == generation)
3084 && (page_table[i].write_protected_cleared != 0)) {
3085 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
3087 "/page bytes_used=%d region_start_offset=%lu dont_move=%d\n",
3088 page_table[i].bytes_used,
3089 page_table[i].region_start_offset,
3090 page_table[i].dont_move));
3091 lose("write to protected page %d in scavenge_generation()\n", i);
3098 /* Scavenge a newspace generation. As it is scavenged new objects may
3099 * be allocated to it; these will also need to be scavenged. This
3100 * repeats until there are no more objects unscavenged in the
3101 * newspace generation.
3103 * To help improve the efficiency, areas written are recorded by
3104 * gc_alloc() and only these scavenged. Sometimes a little more will be
3105 * scavenged, but this causes no harm. An easy check is done that the
3106 * scavenged bytes equals the number allocated in the previous
3109 * Write-protected pages are not scanned except if they are marked
3110 * dont_move in which case they may have been promoted and still have
3111 * pointers to the from space.
3113 * Write-protected pages could potentially be written by alloc however
3114 * to avoid having to handle re-scavenging of write-protected pages
3115 * gc_alloc() does not write to write-protected pages.
3117 * New areas of objects allocated are recorded alternatively in the two
3118 * new_areas arrays below. */
3119 static struct new_area new_areas_1[NUM_NEW_AREAS];
3120 static struct new_area new_areas_2[NUM_NEW_AREAS];
3122 /* Do one full scan of the new space generation. This is not enough to
3123 * complete the job as new objects may be added to the generation in
3124 * the process which are not scavenged. */
3126 scavenge_newspace_generation_one_scan(generation_index_t generation)
3131 "/starting one full scan of newspace generation %d\n",
3133 for (i = 0; i < last_free_page; i++) {
3134 /* Note that this skips over open regions when it encounters them. */
3136 && (page_table[i].bytes_used != 0)
3137 && (page_table[i].gen == generation)
3138 && ((page_table[i].write_protected == 0)
3139 /* (This may be redundant as write_protected is now
3140 * cleared before promotion.) */
3141 || (page_table[i].dont_move == 1))) {
3142 page_index_t last_page;
3145 /* The scavenge will start at the region_start_offset of
3148 * We need to find the full extent of this contiguous
3149 * block in case objects span pages.
3151 * Now work forward until the end of this contiguous area
3152 * is found. A small area is preferred as there is a
3153 * better chance of its pages being write-protected. */
3154 for (last_page = i; ;last_page++) {
3155 /* If all pages are write-protected and movable,
3156 * then no need to scavenge */
3157 all_wp=all_wp && page_table[last_page].write_protected &&
3158 !page_table[last_page].dont_move;
3160 /* Check whether this is the last page in this
3161 * contiguous block */
3162 if ((page_table[last_page].bytes_used < GENCGC_CARD_BYTES)
3163 /* Or it is CARD_BYTES and is the last in the block */
3164 || (!page_boxed_p(last_page+1))
3165 || (page_table[last_page+1].bytes_used == 0)
3166 || (page_table[last_page+1].gen != generation)
3167 || (page_table[last_page+1].region_start_offset == 0))
3171 /* Do a limited check for write-protected pages. */
3173 long nwords = (((unsigned long)
3174 (page_table[last_page].bytes_used
3175 + npage_bytes(last_page-i)
3176 + page_table[i].region_start_offset))
3178 new_areas_ignore_page = last_page;
3180 scavenge(page_region_start(i), nwords);
3187 "/done with one full scan of newspace generation %d\n",
3191 /* Do a complete scavenge of the newspace generation. */
3193 scavenge_newspace_generation(generation_index_t generation)
3197 /* the new_areas array currently being written to by gc_alloc() */
3198 struct new_area (*current_new_areas)[] = &new_areas_1;
3199 long current_new_areas_index;
3201 /* the new_areas created by the previous scavenge cycle */
3202 struct new_area (*previous_new_areas)[] = NULL;
3203 long previous_new_areas_index;
3205 /* Flush the current regions updating the tables. */
3206 gc_alloc_update_all_page_tables();
3208 /* Turn on the recording of new areas by gc_alloc(). */
3209 new_areas = current_new_areas;
3210 new_areas_index = 0;
3212 /* Don't need to record new areas that get scavenged anyway during
3213 * scavenge_newspace_generation_one_scan. */
3214 record_new_objects = 1;
3216 /* Start with a full scavenge. */
3217 scavenge_newspace_generation_one_scan(generation);
3219 /* Record all new areas now. */
3220 record_new_objects = 2;
3222 /* Give a chance to weak hash tables to make other objects live.
3223 * FIXME: The algorithm implemented here for weak hash table gcing
3224 * is O(W^2+N) as Bruno Haible warns in
3225 * http://www.haible.de/bruno/papers/cs/weak/WeakDatastructures-writeup.html
3226 * see "Implementation 2". */
3227 scav_weak_hash_tables();
3229 /* Flush the current regions updating the tables. */
3230 gc_alloc_update_all_page_tables();
3232 /* Grab new_areas_index. */
3233 current_new_areas_index = new_areas_index;
3236 "The first scan is finished; current_new_areas_index=%d.\n",
3237 current_new_areas_index));*/
3239 while (current_new_areas_index > 0) {
3240 /* Move the current to the previous new areas */
3241 previous_new_areas = current_new_areas;
3242 previous_new_areas_index = current_new_areas_index;
3244 /* Scavenge all the areas in previous new areas. Any new areas
3245 * allocated are saved in current_new_areas. */
3247 /* Allocate an array for current_new_areas; alternating between
3248 * new_areas_1 and 2 */
3249 if (previous_new_areas == &new_areas_1)
3250 current_new_areas = &new_areas_2;
3252 current_new_areas = &new_areas_1;
3254 /* Set up for gc_alloc(). */
3255 new_areas = current_new_areas;
3256 new_areas_index = 0;
3258 /* Check whether previous_new_areas had overflowed. */
3259 if (previous_new_areas_index >= NUM_NEW_AREAS) {
3261 /* New areas of objects allocated have been lost so need to do a
3262 * full scan to be sure! If this becomes a problem try
3263 * increasing NUM_NEW_AREAS. */
3264 if (gencgc_verbose) {
3265 SHOW("new_areas overflow, doing full scavenge");
3268 /* Don't need to record new areas that get scavenged
3269 * anyway during scavenge_newspace_generation_one_scan. */
3270 record_new_objects = 1;
3272 scavenge_newspace_generation_one_scan(generation);
3274 /* Record all new areas now. */
3275 record_new_objects = 2;
3277 scav_weak_hash_tables();
3279 /* Flush the current regions updating the tables. */
3280 gc_alloc_update_all_page_tables();
3284 /* Work through previous_new_areas. */
3285 for (i = 0; i < previous_new_areas_index; i++) {
3286 page_index_t page = (*previous_new_areas)[i].page;
3287 size_t offset = (*previous_new_areas)[i].offset;
3288 size_t size = (*previous_new_areas)[i].size / N_WORD_BYTES;
3289 gc_assert((*previous_new_areas)[i].size % N_WORD_BYTES == 0);
3290 scavenge(page_address(page)+offset, size);
3293 scav_weak_hash_tables();
3295 /* Flush the current regions updating the tables. */
3296 gc_alloc_update_all_page_tables();
3299 current_new_areas_index = new_areas_index;
3302 "The re-scan has finished; current_new_areas_index=%d.\n",
3303 current_new_areas_index));*/
3306 /* Turn off recording of areas allocated by gc_alloc(). */
3307 record_new_objects = 0;
3310 /* Check that none of the write_protected pages in this generation
3311 * have been written to. */
3312 for (i = 0; i < page_table_pages; i++) {
3313 if (page_allocated_p(i)
3314 && (page_table[i].bytes_used != 0)
3315 && (page_table[i].gen == generation)
3316 && (page_table[i].write_protected_cleared != 0)
3317 && (page_table[i].dont_move == 0)) {
3318 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d\n",
3319 i, generation, page_table[i].dont_move);
3325 /* Un-write-protect all the pages in from_space. This is done at the
3326 * start of a GC else there may be many page faults while scavenging
3327 * the newspace (I've seen drive the system time to 99%). These pages
3328 * would need to be unprotected anyway before unmapping in
3329 * free_oldspace; not sure what effect this has on paging.. */
3331 unprotect_oldspace(void)
3334 void *region_addr = 0;
3335 void *page_addr = 0;
3336 unsigned long region_bytes = 0;
3338 for (i = 0; i < last_free_page; i++) {
3339 if (page_allocated_p(i)
3340 && (page_table[i].bytes_used != 0)
3341 && (page_table[i].gen == from_space)) {
3343 /* Remove any write-protection. We should be able to rely
3344 * on the write-protect flag to avoid redundant calls. */
3345 if (page_table[i].write_protected) {
3346 page_table[i].write_protected = 0;
3347 page_addr = page_address(i);
3350 region_addr = page_addr;
3351 region_bytes = GENCGC_CARD_BYTES;
3352 } else if (region_addr + region_bytes == page_addr) {
3353 /* Region continue. */
3354 region_bytes += GENCGC_CARD_BYTES;
3356 /* Unprotect previous region. */
3357 os_protect(region_addr, region_bytes, OS_VM_PROT_ALL);
3358 /* First page in new region. */
3359 region_addr = page_addr;
3360 region_bytes = GENCGC_CARD_BYTES;
3366 /* Unprotect last region. */
3367 os_protect(region_addr, region_bytes, OS_VM_PROT_ALL);
3371 /* Work through all the pages and free any in from_space. This
3372 * assumes that all objects have been copied or promoted to an older
3373 * generation. Bytes_allocated and the generation bytes_allocated
3374 * counter are updated. The number of bytes freed is returned. */
3375 static unsigned long
3378 unsigned long bytes_freed = 0;
3379 page_index_t first_page, last_page;
3384 /* Find a first page for the next region of pages. */
3385 while ((first_page < last_free_page)
3386 && (page_free_p(first_page)
3387 || (page_table[first_page].bytes_used == 0)
3388 || (page_table[first_page].gen != from_space)))
3391 if (first_page >= last_free_page)
3394 /* Find the last page of this region. */
3395 last_page = first_page;
3398 /* Free the page. */
3399 bytes_freed += page_table[last_page].bytes_used;
3400 generations[page_table[last_page].gen].bytes_allocated -=
3401 page_table[last_page].bytes_used;
3402 page_table[last_page].allocated = FREE_PAGE_FLAG;
3403 page_table[last_page].bytes_used = 0;
3404 /* Should already be unprotected by unprotect_oldspace(). */
3405 gc_assert(!page_table[last_page].write_protected);
3408 while ((last_page < last_free_page)
3409 && page_allocated_p(last_page)
3410 && (page_table[last_page].bytes_used != 0)
3411 && (page_table[last_page].gen == from_space));
3413 #ifdef READ_PROTECT_FREE_PAGES
3414 os_protect(page_address(first_page),
3415 npage_bytes(last_page-first_page),
3418 first_page = last_page;
3419 } while (first_page < last_free_page);
3421 bytes_allocated -= bytes_freed;
3426 /* Print some information about a pointer at the given address. */
3428 print_ptr(lispobj *addr)
3430 /* If addr is in the dynamic space then out the page information. */
3431 page_index_t pi1 = find_page_index((void*)addr);
3434 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %lu dont_move %d\n",
3435 (unsigned long) addr,
3437 page_table[pi1].allocated,
3438 page_table[pi1].gen,
3439 page_table[pi1].bytes_used,
3440 page_table[pi1].region_start_offset,
3441 page_table[pi1].dont_move);
3442 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
3456 is_in_stack_space(lispobj ptr)
3458 /* For space verification: Pointers can be valid if they point
3459 * to a thread stack space. This would be faster if the thread
3460 * structures had page-table entries as if they were part of
3461 * the heap space. */
3463 for_each_thread(th) {
3464 if ((th->control_stack_start <= (lispobj *)ptr) &&
3465 (th->control_stack_end >= (lispobj *)ptr)) {
3473 verify_space(lispobj *start, size_t words)
3475 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
3476 int is_in_readonly_space =
3477 (READ_ONLY_SPACE_START <= (unsigned long)start &&
3478 (unsigned long)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3482 lispobj thing = *(lispobj*)start;
3484 if (is_lisp_pointer(thing)) {
3485 page_index_t page_index = find_page_index((void*)thing);
3486 long to_readonly_space =
3487 (READ_ONLY_SPACE_START <= thing &&
3488 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
3489 long to_static_space =
3490 (STATIC_SPACE_START <= thing &&
3491 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
3493 /* Does it point to the dynamic space? */
3494 if (page_index != -1) {
3495 /* If it's within the dynamic space it should point to a used
3496 * page. XX Could check the offset too. */
3497 if (page_allocated_p(page_index)
3498 && (page_table[page_index].bytes_used == 0))
3499 lose ("Ptr %p @ %p sees free page.\n", thing, start);
3500 /* Check that it doesn't point to a forwarding pointer! */
3501 if (*((lispobj *)native_pointer(thing)) == 0x01) {
3502 lose("Ptr %p @ %p sees forwarding ptr.\n", thing, start);
3504 /* Check that its not in the RO space as it would then be a
3505 * pointer from the RO to the dynamic space. */
3506 if (is_in_readonly_space) {
3507 lose("ptr to dynamic space %p from RO space %x\n",
3510 /* Does it point to a plausible object? This check slows
3511 * it down a lot (so it's commented out).
3513 * "a lot" is serious: it ate 50 minutes cpu time on
3514 * my duron 950 before I came back from lunch and
3517 * FIXME: Add a variable to enable this
3520 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
3521 lose("ptr %p to invalid object %p\n", thing, start);
3525 extern void funcallable_instance_tramp;
3526 /* Verify that it points to another valid space. */
3527 if (!to_readonly_space && !to_static_space
3528 && (thing != (lispobj)&funcallable_instance_tramp)
3529 && !is_in_stack_space(thing)) {
3530 lose("Ptr %p @ %p sees junk.\n", thing, start);
3534 if (!(fixnump(thing))) {
3536 switch(widetag_of(*start)) {
3539 case SIMPLE_VECTOR_WIDETAG:
3541 case COMPLEX_WIDETAG:
3542 case SIMPLE_ARRAY_WIDETAG:
3543 case COMPLEX_BASE_STRING_WIDETAG:
3544 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
3545 case COMPLEX_CHARACTER_STRING_WIDETAG:
3547 case COMPLEX_VECTOR_NIL_WIDETAG:
3548 case COMPLEX_BIT_VECTOR_WIDETAG:
3549 case COMPLEX_VECTOR_WIDETAG:
3550 case COMPLEX_ARRAY_WIDETAG:
3551 case CLOSURE_HEADER_WIDETAG:
3552 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
3553 case VALUE_CELL_HEADER_WIDETAG:
3554 case SYMBOL_HEADER_WIDETAG:
3555 case CHARACTER_WIDETAG:
3556 #if N_WORD_BITS == 64
3557 case SINGLE_FLOAT_WIDETAG:
3559 case UNBOUND_MARKER_WIDETAG:
3564 case INSTANCE_HEADER_WIDETAG:
3567 long ntotal = HeaderValue(thing);
3568 lispobj layout = ((struct instance *)start)->slots[0];
3573 nuntagged = ((struct layout *)
3574 native_pointer(layout))->n_untagged_slots;
3575 verify_space(start + 1,
3576 ntotal - fixnum_value(nuntagged));
3580 case CODE_HEADER_WIDETAG:
3582 lispobj object = *start;
3584 long nheader_words, ncode_words, nwords;
3586 struct simple_fun *fheaderp;
3588 code = (struct code *) start;
3590 /* Check that it's not in the dynamic space.
3591 * FIXME: Isn't is supposed to be OK for code
3592 * objects to be in the dynamic space these days? */
3593 if (is_in_dynamic_space
3594 /* It's ok if it's byte compiled code. The trace
3595 * table offset will be a fixnum if it's x86
3596 * compiled code - check.
3598 * FIXME: #^#@@! lack of abstraction here..
3599 * This line can probably go away now that
3600 * there's no byte compiler, but I've got
3601 * too much to worry about right now to try
3602 * to make sure. -- WHN 2001-10-06 */
3603 && fixnump(code->trace_table_offset)
3604 /* Only when enabled */
3605 && verify_dynamic_code_check) {
3607 "/code object at %p in the dynamic space\n",
3611 ncode_words = fixnum_value(code->code_size);
3612 nheader_words = HeaderValue(object);
3613 nwords = ncode_words + nheader_words;
3614 nwords = CEILING(nwords, 2);
3615 /* Scavenge the boxed section of the code data block */
3616 verify_space(start + 1, nheader_words - 1);
3618 /* Scavenge the boxed section of each function
3619 * object in the code data block. */
3620 fheaderl = code->entry_points;
3621 while (fheaderl != NIL) {
3623 (struct simple_fun *) native_pointer(fheaderl);
3624 gc_assert(widetag_of(fheaderp->header) ==
3625 SIMPLE_FUN_HEADER_WIDETAG);
3626 verify_space(&fheaderp->name, 1);
3627 verify_space(&fheaderp->arglist, 1);
3628 verify_space(&fheaderp->type, 1);
3629 fheaderl = fheaderp->next;
3635 /* unboxed objects */
3636 case BIGNUM_WIDETAG:
3637 #if N_WORD_BITS != 64
3638 case SINGLE_FLOAT_WIDETAG:
3640 case DOUBLE_FLOAT_WIDETAG:
3641 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3642 case LONG_FLOAT_WIDETAG:
3644 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3645 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3647 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3648 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3650 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3651 case COMPLEX_LONG_FLOAT_WIDETAG:
3653 case SIMPLE_BASE_STRING_WIDETAG:
3654 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
3655 case SIMPLE_CHARACTER_STRING_WIDETAG:
3657 case SIMPLE_BIT_VECTOR_WIDETAG:
3658 case SIMPLE_ARRAY_NIL_WIDETAG:
3659 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3660 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3661 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3662 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3663 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3664 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3665 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG
3666 case SIMPLE_ARRAY_UNSIGNED_BYTE_29_WIDETAG:
3668 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3669 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3670 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG
3671 case SIMPLE_ARRAY_UNSIGNED_BYTE_60_WIDETAG:
3673 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
3674 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
3676 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
3677 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
3679 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3680 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3682 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3683 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3685 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG
3686 case SIMPLE_ARRAY_SIGNED_BYTE_30_WIDETAG:
3688 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3689 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3691 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG
3692 case SIMPLE_ARRAY_SIGNED_BYTE_61_WIDETAG:
3694 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
3695 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
3697 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3698 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3699 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3700 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3702 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3703 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3705 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3706 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3708 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3709 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3712 case WEAK_POINTER_WIDETAG:
3713 #ifdef LUTEX_WIDETAG
3716 #ifdef NO_TLS_VALUE_MARKER_WIDETAG
3717 case NO_TLS_VALUE_MARKER_WIDETAG:
3719 count = (sizetab[widetag_of(*start)])(start);
3723 lose("Unhandled widetag %p at %p\n",
3724 widetag_of(*start), start);
3736 /* FIXME: It would be nice to make names consistent so that
3737 * foo_size meant size *in* *bytes* instead of size in some
3738 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3739 * Some counts of lispobjs are called foo_count; it might be good
3740 * to grep for all foo_size and rename the appropriate ones to
3742 long read_only_space_size =
3743 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3744 - (lispobj*)READ_ONLY_SPACE_START;
3745 long static_space_size =
3746 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3747 - (lispobj*)STATIC_SPACE_START;
3749 for_each_thread(th) {
3750 long binding_stack_size =
3751 (lispobj*)get_binding_stack_pointer(th)
3752 - (lispobj*)th->binding_stack_start;
3753 verify_space(th->binding_stack_start, binding_stack_size);
3755 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3756 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3760 verify_generation(generation_index_t generation)
3764 for (i = 0; i < last_free_page; i++) {
3765 if (page_allocated_p(i)
3766 && (page_table[i].bytes_used != 0)
3767 && (page_table[i].gen == generation)) {
3768 page_index_t last_page;
3769 int region_allocation = page_table[i].allocated;
3771 /* This should be the start of a contiguous block */
3772 gc_assert(page_table[i].region_start_offset == 0);
3774 /* Need to find the full extent of this contiguous block in case
3775 objects span pages. */
3777 /* Now work forward until the end of this contiguous area is
3779 for (last_page = i; ;last_page++)
3780 /* Check whether this is the last page in this contiguous
3782 if ((page_table[last_page].bytes_used < GENCGC_CARD_BYTES)
3783 /* Or it is CARD_BYTES and is the last in the block */
3784 || (page_table[last_page+1].allocated != region_allocation)
3785 || (page_table[last_page+1].bytes_used == 0)
3786 || (page_table[last_page+1].gen != generation)
3787 || (page_table[last_page+1].region_start_offset == 0))
3790 verify_space(page_address(i),
3792 (page_table[last_page].bytes_used
3793 + npage_bytes(last_page-i)))
3800 /* Check that all the free space is zero filled. */
3802 verify_zero_fill(void)
3806 for (page = 0; page < last_free_page; page++) {
3807 if (page_free_p(page)) {
3808 /* The whole page should be zero filled. */
3809 long *start_addr = (long *)page_address(page);
3812 for (i = 0; i < size; i++) {
3813 if (start_addr[i] != 0) {
3814 lose("free page not zero at %x\n", start_addr + i);
3818 long free_bytes = GENCGC_CARD_BYTES - page_table[page].bytes_used;
3819 if (free_bytes > 0) {
3820 long *start_addr = (long *)((unsigned long)page_address(page)
3821 + page_table[page].bytes_used);
3822 long size = free_bytes / N_WORD_BYTES;
3824 for (i = 0; i < size; i++) {
3825 if (start_addr[i] != 0) {
3826 lose("free region not zero at %x\n", start_addr + i);
3834 /* External entry point for verify_zero_fill */
3836 gencgc_verify_zero_fill(void)
3838 /* Flush the alloc regions updating the tables. */
3839 gc_alloc_update_all_page_tables();
3840 SHOW("verifying zero fill");
3845 verify_dynamic_space(void)
3847 generation_index_t i;
3849 for (i = 0; i <= HIGHEST_NORMAL_GENERATION; i++)
3850 verify_generation(i);
3852 if (gencgc_enable_verify_zero_fill)
3856 /* Write-protect all the dynamic boxed pages in the given generation. */
3858 write_protect_generation_pages(generation_index_t generation)
3862 gc_assert(generation < SCRATCH_GENERATION);
3864 for (start = 0; start < last_free_page; start++) {
3865 if (protect_page_p(start, generation)) {
3869 /* Note the page as protected in the page tables. */
3870 page_table[start].write_protected = 1;
3872 for (last = start + 1; last < last_free_page; last++) {
3873 if (!protect_page_p(last, generation))
3875 page_table[last].write_protected = 1;
3878 page_start = (void *)page_address(start);
3880 os_protect(page_start,
3881 npage_bytes(last - start),
3882 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3888 if (gencgc_verbose > 1) {
3890 "/write protected %d of %d pages in generation %d\n",
3891 count_write_protect_generation_pages(generation),
3892 count_generation_pages(generation),
3897 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
3899 scavenge_control_stack(struct thread *th)
3901 lispobj *control_stack =
3902 (lispobj *)(th->control_stack_start);
3903 unsigned long control_stack_size =
3904 access_control_stack_pointer(th) - control_stack;
3906 scavenge(control_stack, control_stack_size);
3910 #if defined(LISP_FEATURE_SB_THREAD) && (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
3912 preserve_context_registers (os_context_t *c)
3915 /* On Darwin the signal context isn't a contiguous block of memory,
3916 * so just preserve_pointering its contents won't be sufficient.
3918 #if defined(LISP_FEATURE_DARWIN)
3919 #if defined LISP_FEATURE_X86
3920 preserve_pointer((void*)*os_context_register_addr(c,reg_EAX));
3921 preserve_pointer((void*)*os_context_register_addr(c,reg_ECX));
3922 preserve_pointer((void*)*os_context_register_addr(c,reg_EDX));
3923 preserve_pointer((void*)*os_context_register_addr(c,reg_EBX));
3924 preserve_pointer((void*)*os_context_register_addr(c,reg_ESI));
3925 preserve_pointer((void*)*os_context_register_addr(c,reg_EDI));
3926 preserve_pointer((void*)*os_context_pc_addr(c));
3927 #elif defined LISP_FEATURE_X86_64
3928 preserve_pointer((void*)*os_context_register_addr(c,reg_RAX));
3929 preserve_pointer((void*)*os_context_register_addr(c,reg_RCX));
3930 preserve_pointer((void*)*os_context_register_addr(c,reg_RDX));
3931 preserve_pointer((void*)*os_context_register_addr(c,reg_RBX));
3932 preserve_pointer((void*)*os_context_register_addr(c,reg_RSI));
3933 preserve_pointer((void*)*os_context_register_addr(c,reg_RDI));
3934 preserve_pointer((void*)*os_context_register_addr(c,reg_R8));
3935 preserve_pointer((void*)*os_context_register_addr(c,reg_R9));
3936 preserve_pointer((void*)*os_context_register_addr(c,reg_R10));
3937 preserve_pointer((void*)*os_context_register_addr(c,reg_R11));
3938 preserve_pointer((void*)*os_context_register_addr(c,reg_R12));
3939 preserve_pointer((void*)*os_context_register_addr(c,reg_R13));
3940 preserve_pointer((void*)*os_context_register_addr(c,reg_R14));
3941 preserve_pointer((void*)*os_context_register_addr(c,reg_R15));
3942 preserve_pointer((void*)*os_context_pc_addr(c));
3944 #error "preserve_context_registers needs to be tweaked for non-x86 Darwin"
3947 for(ptr = ((void **)(c+1))-1; ptr>=(void **)c; ptr--) {
3948 preserve_pointer(*ptr);
3953 /* Garbage collect a generation. If raise is 0 then the remains of the
3954 * generation are not raised to the next generation. */
3956 garbage_collect_generation(generation_index_t generation, int raise)
3958 unsigned long bytes_freed;
3960 unsigned long static_space_size;
3963 gc_assert(generation <= HIGHEST_NORMAL_GENERATION);
3965 /* The oldest generation can't be raised. */
3966 gc_assert((generation != HIGHEST_NORMAL_GENERATION) || (raise == 0));
3968 /* Check if weak hash tables were processed in the previous GC. */
3969 gc_assert(weak_hash_tables == NULL);
3971 /* Initialize the weak pointer list. */
3972 weak_pointers = NULL;
3974 #ifdef LUTEX_WIDETAG
3975 unmark_lutexes(generation);
3978 /* When a generation is not being raised it is transported to a
3979 * temporary generation (NUM_GENERATIONS), and lowered when
3980 * done. Set up this new generation. There should be no pages
3981 * allocated to it yet. */
3983 gc_assert(generations[SCRATCH_GENERATION].bytes_allocated == 0);
3986 /* Set the global src and dest. generations */
3987 from_space = generation;
3989 new_space = generation+1;
3991 new_space = SCRATCH_GENERATION;
3993 /* Change to a new space for allocation, resetting the alloc_start_page */
3994 gc_alloc_generation = new_space;
3995 generations[new_space].alloc_start_page = 0;
3996 generations[new_space].alloc_unboxed_start_page = 0;
3997 generations[new_space].alloc_large_start_page = 0;
3998 generations[new_space].alloc_large_unboxed_start_page = 0;
4000 /* Before any pointers are preserved, the dont_move flags on the
4001 * pages need to be cleared. */
4002 for (i = 0; i < last_free_page; i++)
4003 if(page_table[i].gen==from_space)
4004 page_table[i].dont_move = 0;
4006 /* Un-write-protect the old-space pages. This is essential for the
4007 * promoted pages as they may contain pointers into the old-space
4008 * which need to be scavenged. It also helps avoid unnecessary page
4009 * faults as forwarding pointers are written into them. They need to
4010 * be un-protected anyway before unmapping later. */
4011 unprotect_oldspace();
4013 /* Scavenge the stacks' conservative roots. */
4015 /* there are potentially two stacks for each thread: the main
4016 * stack, which may contain Lisp pointers, and the alternate stack.
4017 * We don't ever run Lisp code on the altstack, but it may
4018 * host a sigcontext with lisp objects in it */
4020 /* what we need to do: (1) find the stack pointer for the main
4021 * stack; scavenge it (2) find the interrupt context on the
4022 * alternate stack that might contain lisp values, and scavenge
4025 /* we assume that none of the preceding applies to the thread that
4026 * initiates GC. If you ever call GC from inside an altstack
4027 * handler, you will lose. */
4029 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
4030 /* And if we're saving a core, there's no point in being conservative. */
4031 if (conservative_stack) {
4032 for_each_thread(th) {
4034 void **esp=(void **)-1;
4035 #ifdef LISP_FEATURE_SB_THREAD
4037 if(th==arch_os_get_current_thread()) {
4038 /* Somebody is going to burn in hell for this, but casting
4039 * it in two steps shuts gcc up about strict aliasing. */
4040 esp = (void **)((void *)&raise);
4043 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
4044 for(i=free-1;i>=0;i--) {
4045 os_context_t *c=th->interrupt_contexts[i];
4046 esp1 = (void **) *os_context_register_addr(c,reg_SP);
4047 if (esp1>=(void **)th->control_stack_start &&
4048 esp1<(void **)th->control_stack_end) {
4049 if(esp1<esp) esp=esp1;
4050 preserve_context_registers(c);
4055 esp = (void **)((void *)&raise);
4057 for (ptr = ((void **)th->control_stack_end)-1; ptr >= esp; ptr--) {
4058 preserve_pointer(*ptr);
4063 /* Non-x86oid systems don't have "conservative roots" as such, but
4064 * the same mechanism is used for objects pinned for use by alien
4066 for_each_thread(th) {
4067 lispobj pin_list = SymbolTlValue(PINNED_OBJECTS,th);
4068 while (pin_list != NIL) {
4069 struct cons *list_entry =
4070 (struct cons *)native_pointer(pin_list);
4071 preserve_pointer(list_entry->car);
4072 pin_list = list_entry->cdr;
4078 if (gencgc_verbose > 1) {
4079 long num_dont_move_pages = count_dont_move_pages();
4081 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
4082 num_dont_move_pages,
4083 npage_bytes(num_dont_move_pages));
4087 /* Scavenge all the rest of the roots. */
4089 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
4091 * If not x86, we need to scavenge the interrupt context(s) and the
4096 for_each_thread(th) {
4097 scavenge_interrupt_contexts(th);
4098 scavenge_control_stack(th);
4101 /* Scrub the unscavenged control stack space, so that we can't run
4102 * into any stale pointers in a later GC (this is done by the
4103 * stop-for-gc handler in the other threads). */
4104 scrub_control_stack();
4108 /* Scavenge the Lisp functions of the interrupt handlers, taking
4109 * care to avoid SIG_DFL and SIG_IGN. */
4110 for (i = 0; i < NSIG; i++) {
4111 union interrupt_handler handler = interrupt_handlers[i];
4112 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
4113 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
4114 scavenge((lispobj *)(interrupt_handlers + i), 1);
4117 /* Scavenge the binding stacks. */
4120 for_each_thread(th) {
4121 long len= (lispobj *)get_binding_stack_pointer(th) -
4122 th->binding_stack_start;
4123 scavenge((lispobj *) th->binding_stack_start,len);
4124 #ifdef LISP_FEATURE_SB_THREAD
4125 /* do the tls as well */
4126 len=fixnum_value(SymbolValue(FREE_TLS_INDEX,0)) -
4127 (sizeof (struct thread))/(sizeof (lispobj));
4128 scavenge((lispobj *) (th+1),len);
4133 /* The original CMU CL code had scavenge-read-only-space code
4134 * controlled by the Lisp-level variable
4135 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
4136 * wasn't documented under what circumstances it was useful or
4137 * safe to turn it on, so it's been turned off in SBCL. If you
4138 * want/need this functionality, and can test and document it,
4139 * please submit a patch. */
4141 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
4142 unsigned long read_only_space_size =
4143 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
4144 (lispobj*)READ_ONLY_SPACE_START;
4146 "/scavenge read only space: %d bytes\n",
4147 read_only_space_size * sizeof(lispobj)));
4148 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
4152 /* Scavenge static space. */
4154 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
4155 (lispobj *)STATIC_SPACE_START;
4156 if (gencgc_verbose > 1) {
4158 "/scavenge static space: %d bytes\n",
4159 static_space_size * sizeof(lispobj)));
4161 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
4163 /* All generations but the generation being GCed need to be
4164 * scavenged. The new_space generation needs special handling as
4165 * objects may be moved in - it is handled separately below. */
4166 scavenge_generations(generation+1, PSEUDO_STATIC_GENERATION);
4168 /* Finally scavenge the new_space generation. Keep going until no
4169 * more objects are moved into the new generation */
4170 scavenge_newspace_generation(new_space);
4172 /* FIXME: I tried reenabling this check when debugging unrelated
4173 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
4174 * Since the current GC code seems to work well, I'm guessing that
4175 * this debugging code is just stale, but I haven't tried to
4176 * figure it out. It should be figured out and then either made to
4177 * work or just deleted. */
4178 #define RESCAN_CHECK 0
4180 /* As a check re-scavenge the newspace once; no new objects should
4183 long old_bytes_allocated = bytes_allocated;
4184 long bytes_allocated;
4186 /* Start with a full scavenge. */
4187 scavenge_newspace_generation_one_scan(new_space);
4189 /* Flush the current regions, updating the tables. */
4190 gc_alloc_update_all_page_tables();
4192 bytes_allocated = bytes_allocated - old_bytes_allocated;
4194 if (bytes_allocated != 0) {
4195 lose("Rescan of new_space allocated %d more bytes.\n",
4201 scan_weak_hash_tables();
4202 scan_weak_pointers();
4204 /* Flush the current regions, updating the tables. */
4205 gc_alloc_update_all_page_tables();
4207 /* Free the pages in oldspace, but not those marked dont_move. */
4208 bytes_freed = free_oldspace();
4210 /* If the GC is not raising the age then lower the generation back
4211 * to its normal generation number */
4213 for (i = 0; i < last_free_page; i++)
4214 if ((page_table[i].bytes_used != 0)
4215 && (page_table[i].gen == SCRATCH_GENERATION))
4216 page_table[i].gen = generation;
4217 gc_assert(generations[generation].bytes_allocated == 0);
4218 generations[generation].bytes_allocated =
4219 generations[SCRATCH_GENERATION].bytes_allocated;
4220 generations[SCRATCH_GENERATION].bytes_allocated = 0;
4223 /* Reset the alloc_start_page for generation. */
4224 generations[generation].alloc_start_page = 0;
4225 generations[generation].alloc_unboxed_start_page = 0;
4226 generations[generation].alloc_large_start_page = 0;
4227 generations[generation].alloc_large_unboxed_start_page = 0;
4229 if (generation >= verify_gens) {
4230 if (gencgc_verbose) {
4234 verify_dynamic_space();
4237 /* Set the new gc trigger for the GCed generation. */
4238 generations[generation].gc_trigger =
4239 generations[generation].bytes_allocated
4240 + generations[generation].bytes_consed_between_gc;
4243 generations[generation].num_gc = 0;
4245 ++generations[generation].num_gc;
4247 #ifdef LUTEX_WIDETAG
4248 reap_lutexes(generation);
4250 move_lutexes(generation, generation+1);
4254 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
4256 update_dynamic_space_free_pointer(void)
4258 page_index_t last_page = -1, i;
4260 for (i = 0; i < last_free_page; i++)
4261 if (page_allocated_p(i) && (page_table[i].bytes_used != 0))
4264 last_free_page = last_page+1;
4266 set_alloc_pointer((lispobj)(page_address(last_free_page)));
4267 return 0; /* dummy value: return something ... */
4271 remap_page_range (page_index_t from, page_index_t to, int forcibly)
4273 /* There's a mysterious Solaris/x86 problem with using mmap
4274 * tricks for memory zeroing. See sbcl-devel thread
4275 * "Re: patch: standalone executable redux".
4277 * Since pages don't have to be zeroed ahead of time, only do
4278 * so when called from purify.
4280 #if defined(LISP_FEATURE_SUNOS)
4282 zero_pages(from, to);
4285 release_granularity = gencgc_release_granularity/GENCGC_CARD_BYTES,
4286 release_mask = release_granularity-1,
4288 aligned_from = (from+release_mask)&~release_mask,
4289 aligned_end = (end&~release_mask);
4291 if (aligned_from < aligned_end) {
4292 zero_pages_with_mmap(aligned_from, aligned_end-1);
4294 if (aligned_from != from)
4295 zero_pages(from, aligned_from-1);
4296 if (aligned_end != end)
4297 zero_pages(aligned_end, end-1);
4299 } else if (forcibly)
4300 zero_pages(from, to);
4305 remap_free_pages (page_index_t from, page_index_t to, int forcibly)
4307 page_index_t first_page, last_page,
4308 first_aligned_page, last_aligned_page;
4311 return remap_page_range(from, to, 1);
4313 /* See comment above about mysterious failures on Solaris/x86.
4315 #if !defined(LISP_FEATURE_SUNOS)
4316 for (first_page = from; first_page <= to; first_page++) {
4317 if (page_allocated_p(first_page) ||
4318 (page_table[first_page].need_to_zero == 0))
4321 last_page = first_page + 1;
4322 while (page_free_p(last_page) &&
4323 (last_page <= to) &&
4324 (page_table[last_page].need_to_zero == 1))
4327 remap_page_range(first_page, last_page-1, 0);
4329 first_page = last_page;
4334 generation_index_t small_generation_limit = 1;
4336 /* GC all generations newer than last_gen, raising the objects in each
4337 * to the next older generation - we finish when all generations below
4338 * last_gen are empty. Then if last_gen is due for a GC, or if
4339 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
4340 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
4342 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
4343 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
4345 collect_garbage(generation_index_t last_gen)
4347 generation_index_t gen = 0, i;
4350 /* The largest value of last_free_page seen since the time
4351 * remap_free_pages was called. */
4352 static page_index_t high_water_mark = 0;
4354 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
4355 log_generation_stats(gc_logfile, "=== GC Start ===");
4359 if (last_gen > HIGHEST_NORMAL_GENERATION+1) {
4361 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
4366 /* Flush the alloc regions updating the tables. */
4367 gc_alloc_update_all_page_tables();
4369 /* Verify the new objects created by Lisp code. */
4370 if (pre_verify_gen_0) {
4371 FSHOW((stderr, "pre-checking generation 0\n"));
4372 verify_generation(0);
4375 if (gencgc_verbose > 1)
4376 print_generation_stats();
4379 /* Collect the generation. */
4381 if (gen >= gencgc_oldest_gen_to_gc) {
4382 /* Never raise the oldest generation. */
4387 || (generations[gen].num_gc >= generations[gen].number_of_gcs_before_promotion);
4390 if (gencgc_verbose > 1) {
4392 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
4395 generations[gen].bytes_allocated,
4396 generations[gen].gc_trigger,
4397 generations[gen].num_gc));
4400 /* If an older generation is being filled, then update its
4403 generations[gen+1].cum_sum_bytes_allocated +=
4404 generations[gen+1].bytes_allocated;
4407 garbage_collect_generation(gen, raise);
4409 /* Reset the memory age cum_sum. */
4410 generations[gen].cum_sum_bytes_allocated = 0;
4412 if (gencgc_verbose > 1) {
4413 FSHOW((stderr, "GC of generation %d finished:\n", gen));
4414 print_generation_stats();
4418 } while ((gen <= gencgc_oldest_gen_to_gc)
4419 && ((gen < last_gen)
4420 || ((gen <= gencgc_oldest_gen_to_gc)
4422 && (generations[gen].bytes_allocated
4423 > generations[gen].gc_trigger)
4424 && (generation_average_age(gen)
4425 > generations[gen].minimum_age_before_gc))));
4427 /* Now if gen-1 was raised all generations before gen are empty.
4428 * If it wasn't raised then all generations before gen-1 are empty.
4430 * Now objects within this gen's pages cannot point to younger
4431 * generations unless they are written to. This can be exploited
4432 * by write-protecting the pages of gen; then when younger
4433 * generations are GCed only the pages which have been written
4438 gen_to_wp = gen - 1;
4440 /* There's not much point in WPing pages in generation 0 as it is
4441 * never scavenged (except promoted pages). */
4442 if ((gen_to_wp > 0) && enable_page_protection) {
4443 /* Check that they are all empty. */
4444 for (i = 0; i < gen_to_wp; i++) {
4445 if (generations[i].bytes_allocated)
4446 lose("trying to write-protect gen. %d when gen. %d nonempty\n",
4449 write_protect_generation_pages(gen_to_wp);
4452 /* Set gc_alloc() back to generation 0. The current regions should
4453 * be flushed after the above GCs. */
4454 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
4455 gc_alloc_generation = 0;
4457 /* Save the high-water mark before updating last_free_page */
4458 if (last_free_page > high_water_mark)
4459 high_water_mark = last_free_page;
4461 update_dynamic_space_free_pointer();
4463 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
4465 fprintf(stderr,"Next gc when %ld bytes have been consed\n",
4468 /* If we did a big GC (arbitrarily defined as gen > 1), release memory
4471 if (gen > small_generation_limit) {
4472 if (last_free_page > high_water_mark)
4473 high_water_mark = last_free_page;
4474 remap_free_pages(0, high_water_mark, 0);
4475 high_water_mark = 0;
4480 log_generation_stats(gc_logfile, "=== GC End ===");
4481 SHOW("returning from collect_garbage");
4484 /* This is called by Lisp PURIFY when it is finished. All live objects
4485 * will have been moved to the RO and Static heaps. The dynamic space
4486 * will need a full re-initialization. We don't bother having Lisp
4487 * PURIFY flush the current gc_alloc() region, as the page_tables are
4488 * re-initialized, and every page is zeroed to be sure. */
4492 page_index_t page, last_page;
4494 if (gencgc_verbose > 1) {
4495 SHOW("entering gc_free_heap");
4498 for (page = 0; page < page_table_pages; page++) {
4499 /* Skip free pages which should already be zero filled. */
4500 if (page_allocated_p(page)) {
4501 void *page_start, *addr;
4502 for (last_page = page;
4503 (last_page < page_table_pages) && page_allocated_p(last_page);
4505 /* Mark the page free. The other slots are assumed invalid
4506 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
4507 * should not be write-protected -- except that the
4508 * generation is used for the current region but it sets
4510 page_table[page].allocated = FREE_PAGE_FLAG;
4511 page_table[page].bytes_used = 0;
4512 page_table[page].write_protected = 0;
4515 #ifndef LISP_FEATURE_WIN32 /* Pages already zeroed on win32? Not sure
4516 * about this change. */
4517 page_start = (void *)page_address(page);
4518 os_protect(page_start, npage_bytes(last_page-page), OS_VM_PROT_ALL);
4519 remap_free_pages(page, last_page-1, 1);
4522 } else if (gencgc_zero_check_during_free_heap) {
4523 /* Double-check that the page is zero filled. */
4526 gc_assert(page_free_p(page));
4527 gc_assert(page_table[page].bytes_used == 0);
4528 page_start = (long *)page_address(page);
4529 for (i=0; i<GENCGC_CARD_BYTES/sizeof(long); i++) {
4530 if (page_start[i] != 0) {
4531 lose("free region not zero at %x\n", page_start + i);
4537 bytes_allocated = 0;
4539 /* Initialize the generations. */
4540 for (page = 0; page < NUM_GENERATIONS; page++) {
4541 generations[page].alloc_start_page = 0;
4542 generations[page].alloc_unboxed_start_page = 0;
4543 generations[page].alloc_large_start_page = 0;
4544 generations[page].alloc_large_unboxed_start_page = 0;
4545 generations[page].bytes_allocated = 0;
4546 generations[page].gc_trigger = 2000000;
4547 generations[page].num_gc = 0;
4548 generations[page].cum_sum_bytes_allocated = 0;
4549 generations[page].lutexes = NULL;
4552 if (gencgc_verbose > 1)
4553 print_generation_stats();
4555 /* Initialize gc_alloc(). */
4556 gc_alloc_generation = 0;
4558 gc_set_region_empty(&boxed_region);
4559 gc_set_region_empty(&unboxed_region);
4562 set_alloc_pointer((lispobj)((char *)heap_base));
4564 if (verify_after_free_heap) {
4565 /* Check whether purify has left any bad pointers. */
4566 FSHOW((stderr, "checking after free_heap\n"));
4576 /* Compute the number of pages needed for the dynamic space.
4577 * Dynamic space size should be aligned on page size. */
4578 page_table_pages = dynamic_space_size/GENCGC_CARD_BYTES;
4579 gc_assert(dynamic_space_size == npage_bytes(page_table_pages));
4581 /* The page_table must be allocated using "calloc" to initialize
4582 * the page structures correctly. There used to be a separate
4583 * initialization loop (now commented out; see below) but that was
4584 * unnecessary and did hurt startup time. */
4585 page_table = calloc(page_table_pages, sizeof(struct page));
4586 gc_assert(page_table);
4589 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
4590 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
4592 #ifdef LUTEX_WIDETAG
4593 scavtab[LUTEX_WIDETAG] = scav_lutex;
4594 transother[LUTEX_WIDETAG] = trans_lutex;
4595 sizetab[LUTEX_WIDETAG] = size_lutex;
4598 heap_base = (void*)DYNAMIC_SPACE_START;
4600 /* The page structures are initialized implicitly when page_table
4601 * is allocated with "calloc" above. Formerly we had the following
4602 * explicit initialization here (comments converted to C99 style
4603 * for readability as C's block comments don't nest):
4605 * // Initialize each page structure.
4606 * for (i = 0; i < page_table_pages; i++) {
4607 * // Initialize all pages as free.
4608 * page_table[i].allocated = FREE_PAGE_FLAG;
4609 * page_table[i].bytes_used = 0;
4611 * // Pages are not write-protected at startup.
4612 * page_table[i].write_protected = 0;
4615 * Without this loop the image starts up much faster when dynamic
4616 * space is large -- which it is on 64-bit platforms already by
4617 * default -- and when "calloc" for large arrays is implemented
4618 * using copy-on-write of a page of zeroes -- which it is at least
4619 * on Linux. In this case the pages that page_table_pages is stored
4620 * in are mapped and cleared not before the corresponding part of
4621 * dynamic space is used. For example, this saves clearing 16 MB of
4622 * memory at startup if the page size is 4 KB and the size of
4623 * dynamic space is 4 GB.
4624 * FREE_PAGE_FLAG must be 0 for this to work correctly which is
4625 * asserted below: */
4627 /* Compile time assertion: If triggered, declares an array
4628 * of dimension -1 forcing a syntax error. The intent of the
4629 * assignment is to avoid an "unused variable" warning. */
4630 char assert_free_page_flag_0[(FREE_PAGE_FLAG) ? -1 : 1];
4631 assert_free_page_flag_0[0] = assert_free_page_flag_0[0];
4634 bytes_allocated = 0;
4636 /* Initialize the generations.
4638 * FIXME: very similar to code in gc_free_heap(), should be shared */
4639 for (i = 0; i < NUM_GENERATIONS; i++) {
4640 generations[i].alloc_start_page = 0;
4641 generations[i].alloc_unboxed_start_page = 0;
4642 generations[i].alloc_large_start_page = 0;
4643 generations[i].alloc_large_unboxed_start_page = 0;
4644 generations[i].bytes_allocated = 0;
4645 generations[i].gc_trigger = 2000000;
4646 generations[i].num_gc = 0;
4647 generations[i].cum_sum_bytes_allocated = 0;
4648 /* the tune-able parameters */
4649 generations[i].bytes_consed_between_gc = 2000000;
4650 generations[i].number_of_gcs_before_promotion = 1;
4651 generations[i].minimum_age_before_gc = 0.75;
4652 generations[i].lutexes = NULL;
4655 /* Initialize gc_alloc. */
4656 gc_alloc_generation = 0;
4657 gc_set_region_empty(&boxed_region);
4658 gc_set_region_empty(&unboxed_region);
4663 /* Pick up the dynamic space from after a core load.
4665 * The ALLOCATION_POINTER points to the end of the dynamic space.
4669 gencgc_pickup_dynamic(void)
4671 page_index_t page = 0;
4672 void *alloc_ptr = (void *)get_alloc_pointer();
4673 lispobj *prev=(lispobj *)page_address(page);
4674 generation_index_t gen = PSEUDO_STATIC_GENERATION;
4676 lispobj *first,*ptr= (lispobj *)page_address(page);
4678 if (!gencgc_partial_pickup || page_allocated_p(page)) {
4679 /* It is possible, though rare, for the saved page table
4680 * to contain free pages below alloc_ptr. */
4681 page_table[page].gen = gen;
4682 page_table[page].bytes_used = GENCGC_CARD_BYTES;
4683 page_table[page].large_object = 0;
4684 page_table[page].write_protected = 0;
4685 page_table[page].write_protected_cleared = 0;
4686 page_table[page].dont_move = 0;
4687 page_table[page].need_to_zero = 1;
4690 if (!gencgc_partial_pickup) {
4691 page_table[page].allocated = BOXED_PAGE_FLAG;
4692 first=gc_search_space(prev,(ptr+2)-prev,ptr);
4695 page_table[page].region_start_offset =
4696 page_address(page) - (void *)prev;
4699 } while (page_address(page) < alloc_ptr);
4701 #ifdef LUTEX_WIDETAG
4702 /* Lutexes have been registered in generation 0 by coreparse, and
4703 * need to be moved to the right one manually.
4705 move_lutexes(0, PSEUDO_STATIC_GENERATION);
4708 last_free_page = page;
4710 generations[gen].bytes_allocated = npage_bytes(page);
4711 bytes_allocated = npage_bytes(page);
4713 gc_alloc_update_all_page_tables();
4714 write_protect_generation_pages(gen);
4718 gc_initialize_pointers(void)
4720 gencgc_pickup_dynamic();
4724 /* alloc(..) is the external interface for memory allocation. It
4725 * allocates to generation 0. It is not called from within the garbage
4726 * collector as it is only external uses that need the check for heap
4727 * size (GC trigger) and to disable the interrupts (interrupts are
4728 * always disabled during a GC).
4730 * The vops that call alloc(..) assume that the returned space is zero-filled.
4731 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4733 * The check for a GC trigger is only performed when the current
4734 * region is full, so in most cases it's not needed. */
4736 static inline lispobj *
4737 general_alloc_internal(long nbytes, int page_type_flag, struct alloc_region *region,
4738 struct thread *thread)
4740 #ifndef LISP_FEATURE_WIN32
4741 lispobj alloc_signal;
4744 void *new_free_pointer;
4746 gc_assert(nbytes>0);
4748 /* Check for alignment allocation problems. */
4749 gc_assert((((unsigned long)region->free_pointer & LOWTAG_MASK) == 0)
4750 && ((nbytes & LOWTAG_MASK) == 0));
4752 /* Must be inside a PA section. */
4753 gc_assert(get_pseudo_atomic_atomic(thread));
4755 /* maybe we can do this quickly ... */
4756 new_free_pointer = region->free_pointer + nbytes;
4757 if (new_free_pointer <= region->end_addr) {
4758 new_obj = (void*)(region->free_pointer);
4759 region->free_pointer = new_free_pointer;
4760 return(new_obj); /* yup */
4763 /* we have to go the long way around, it seems. Check whether we
4764 * should GC in the near future
4766 if (auto_gc_trigger && bytes_allocated > auto_gc_trigger) {
4767 /* Don't flood the system with interrupts if the need to gc is
4768 * already noted. This can happen for example when SUB-GC
4769 * allocates or after a gc triggered in a WITHOUT-GCING. */
4770 if (SymbolValue(GC_PENDING,thread) == NIL) {
4771 /* set things up so that GC happens when we finish the PA
4773 SetSymbolValue(GC_PENDING,T,thread);
4774 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
4775 set_pseudo_atomic_interrupted(thread);
4776 #ifdef LISP_FEATURE_PPC
4777 /* PPC calls alloc() from a trap or from pa_alloc(),
4778 * look up the most context if it's from a trap. */
4780 os_context_t *context =
4781 thread->interrupt_data->allocation_trap_context;
4782 maybe_save_gc_mask_and_block_deferrables
4783 (context ? os_context_sigmask_addr(context) : NULL);
4786 maybe_save_gc_mask_and_block_deferrables(NULL);
4791 new_obj = gc_alloc_with_region(nbytes, page_type_flag, region, 0);
4793 #ifndef LISP_FEATURE_WIN32
4794 alloc_signal = SymbolValue(ALLOC_SIGNAL,thread);
4795 if ((alloc_signal & FIXNUM_TAG_MASK) == 0) {
4796 if ((signed long) alloc_signal <= 0) {
4797 SetSymbolValue(ALLOC_SIGNAL, T, thread);
4800 SetSymbolValue(ALLOC_SIGNAL,
4801 alloc_signal - (1 << N_FIXNUM_TAG_BITS),
4811 general_alloc(long nbytes, int page_type_flag)
4813 struct thread *thread = arch_os_get_current_thread();
4814 /* Select correct region, and call general_alloc_internal with it.
4815 * For other then boxed allocation we must lock first, since the
4816 * region is shared. */
4817 if (BOXED_PAGE_FLAG & page_type_flag) {
4818 #ifdef LISP_FEATURE_SB_THREAD
4819 struct alloc_region *region = (thread ? &(thread->alloc_region) : &boxed_region);
4821 struct alloc_region *region = &boxed_region;
4823 return general_alloc_internal(nbytes, page_type_flag, region, thread);
4824 } else if (UNBOXED_PAGE_FLAG == page_type_flag) {
4826 gc_assert(0 == thread_mutex_lock(&allocation_lock));
4827 obj = general_alloc_internal(nbytes, page_type_flag, &unboxed_region, thread);
4828 gc_assert(0 == thread_mutex_unlock(&allocation_lock));
4831 lose("bad page type flag: %d", page_type_flag);
4838 gc_assert(get_pseudo_atomic_atomic(arch_os_get_current_thread()));
4839 return general_alloc(nbytes, BOXED_PAGE_FLAG);
4843 * shared support for the OS-dependent signal handlers which
4844 * catch GENCGC-related write-protect violations
4846 void unhandled_sigmemoryfault(void* addr);
4848 /* Depending on which OS we're running under, different signals might
4849 * be raised for a violation of write protection in the heap. This
4850 * function factors out the common generational GC magic which needs
4851 * to invoked in this case, and should be called from whatever signal
4852 * handler is appropriate for the OS we're running under.
4854 * Return true if this signal is a normal generational GC thing that
4855 * we were able to handle, or false if it was abnormal and control
4856 * should fall through to the general SIGSEGV/SIGBUS/whatever logic. */
4859 gencgc_handle_wp_violation(void* fault_addr)
4861 page_index_t page_index = find_page_index(fault_addr);
4864 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4865 fault_addr, page_index));
4868 /* Check whether the fault is within the dynamic space. */
4869 if (page_index == (-1)) {
4871 /* It can be helpful to be able to put a breakpoint on this
4872 * case to help diagnose low-level problems. */
4873 unhandled_sigmemoryfault(fault_addr);
4875 /* not within the dynamic space -- not our responsibility */
4880 ret = thread_mutex_lock(&free_pages_lock);
4881 gc_assert(ret == 0);
4882 if (page_table[page_index].write_protected) {
4883 /* Unprotect the page. */
4884 os_protect(page_address(page_index), GENCGC_CARD_BYTES, OS_VM_PROT_ALL);
4885 page_table[page_index].write_protected_cleared = 1;
4886 page_table[page_index].write_protected = 0;
4888 /* The only acceptable reason for this signal on a heap
4889 * access is that GENCGC write-protected the page.
4890 * However, if two CPUs hit a wp page near-simultaneously,
4891 * we had better not have the second one lose here if it
4892 * does this test after the first one has already set wp=0
4894 if(page_table[page_index].write_protected_cleared != 1)
4895 lose("fault in heap page %d not marked as write-protected\nboxed_region.first_page: %d, boxed_region.last_page %d\n",
4896 page_index, boxed_region.first_page,
4897 boxed_region.last_page);
4899 ret = thread_mutex_unlock(&free_pages_lock);
4900 gc_assert(ret == 0);
4901 /* Don't worry, we can handle it. */
4905 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4906 * it's not just a case of the program hitting the write barrier, and
4907 * are about to let Lisp deal with it. It's basically just a
4908 * convenient place to set a gdb breakpoint. */
4910 unhandled_sigmemoryfault(void *addr)
4913 void gc_alloc_update_all_page_tables(void)
4915 /* Flush the alloc regions updating the tables. */
4918 gc_alloc_update_page_tables(BOXED_PAGE_FLAG, &th->alloc_region);
4919 gc_alloc_update_page_tables(UNBOXED_PAGE_FLAG, &unboxed_region);
4920 gc_alloc_update_page_tables(BOXED_PAGE_FLAG, &boxed_region);
4924 gc_set_region_empty(struct alloc_region *region)
4926 region->first_page = 0;
4927 region->last_page = -1;
4928 region->start_addr = page_address(0);
4929 region->free_pointer = page_address(0);
4930 region->end_addr = page_address(0);
4934 zero_all_free_pages()
4938 for (i = 0; i < last_free_page; i++) {
4939 if (page_free_p(i)) {
4940 #ifdef READ_PROTECT_FREE_PAGES
4941 os_protect(page_address(i),
4950 /* Things to do before doing a final GC before saving a core (without
4953 * + Pages in large_object pages aren't moved by the GC, so we need to
4954 * unset that flag from all pages.
4955 * + The pseudo-static generation isn't normally collected, but it seems
4956 * reasonable to collect it at least when saving a core. So move the
4957 * pages to a normal generation.
4960 prepare_for_final_gc ()
4963 for (i = 0; i < last_free_page; i++) {
4964 page_table[i].large_object = 0;
4965 if (page_table[i].gen == PSEUDO_STATIC_GENERATION) {
4966 int used = page_table[i].bytes_used;
4967 page_table[i].gen = HIGHEST_NORMAL_GENERATION;
4968 generations[PSEUDO_STATIC_GENERATION].bytes_allocated -= used;
4969 generations[HIGHEST_NORMAL_GENERATION].bytes_allocated += used;
4975 /* Do a non-conservative GC, and then save a core with the initial
4976 * function being set to the value of the static symbol
4977 * SB!VM:RESTART-LISP-FUNCTION */
4979 gc_and_save(char *filename, boolean prepend_runtime,
4980 boolean save_runtime_options)
4983 void *runtime_bytes = NULL;
4984 size_t runtime_size;
4986 file = prepare_to_save(filename, prepend_runtime, &runtime_bytes,
4991 conservative_stack = 0;
4993 /* The filename might come from Lisp, and be moved by the now
4994 * non-conservative GC. */
4995 filename = strdup(filename);
4997 /* Collect twice: once into relatively high memory, and then back
4998 * into low memory. This compacts the retained data into the lower
4999 * pages, minimizing the size of the core file.
5001 prepare_for_final_gc();
5002 gencgc_alloc_start_page = last_free_page;
5003 collect_garbage(HIGHEST_NORMAL_GENERATION+1);
5005 prepare_for_final_gc();
5006 gencgc_alloc_start_page = -1;
5007 collect_garbage(HIGHEST_NORMAL_GENERATION+1);
5009 if (prepend_runtime)
5010 save_runtime_to_filehandle(file, runtime_bytes, runtime_size);
5012 /* The dumper doesn't know that pages need to be zeroed before use. */
5013 zero_all_free_pages();
5014 save_to_filehandle(file, filename, SymbolValue(RESTART_LISP_FUNCTION,0),
5015 prepend_runtime, save_runtime_options);
5016 /* Oops. Save still managed to fail. Since we've mangled the stack
5017 * beyond hope, there's not much we can do.
5018 * (beyond FUNCALLing RESTART_LISP_FUNCTION, but I suspect that's
5019 * going to be rather unsatisfactory too... */
5020 lose("Attempt to save core after non-conservative GC failed.\n");