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(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
56 #include "genesis/cons.h"
59 /* forward declarations */
60 page_index_t gc_find_freeish_pages(page_index_t *restart_page_ptr, long nbytes,
68 /* Generations 0-5 are normal collected generations, 6 is only used as
69 * scratch space by the collector, and should never get collected.
72 SCRATCH_GENERATION = PSEUDO_STATIC_GENERATION+1,
76 /* Should we use page protection to help avoid the scavenging of pages
77 * that don't have pointers to younger generations? */
78 boolean enable_page_protection = 1;
80 /* the minimum size (in bytes) for a large object*/
81 #if (GENCGC_ALLOC_GRANULARITY >= PAGE_BYTES) && (GENCGC_ALLOC_GRANULARITY >= GENCGC_CARD_BYTES)
82 os_vm_size_t large_object_size = 4 * GENCGC_ALLOC_GRANULARITY;
83 #elif (GENCGC_CARD_BYTES >= PAGE_BYTES) && (GENCGC_CARD_BYTES >= GENCGC_ALLOC_GRANULARITY)
84 os_vm_size_t large_object_size = 4 * GENCGC_CARD_BYTES;
86 os_vm_size_t large_object_size = 4 * PAGE_BYTES;
89 /* Largest allocation seen since last GC. */
90 os_vm_size_t large_allocation = 0;
97 /* the verbosity level. All non-error messages are disabled at level 0;
98 * and only a few rare messages are printed at level 1. */
100 boolean gencgc_verbose = 1;
102 boolean gencgc_verbose = 0;
105 /* FIXME: At some point enable the various error-checking things below
106 * and see what they say. */
108 /* We hunt for pointers to old-space, when GCing generations >= verify_gen.
109 * Set verify_gens to HIGHEST_NORMAL_GENERATION + 1 to disable this kind of
111 generation_index_t verify_gens = HIGHEST_NORMAL_GENERATION + 1;
113 /* Should we do a pre-scan verify of generation 0 before it's GCed? */
114 boolean pre_verify_gen_0 = 0;
116 /* Should we check for bad pointers after gc_free_heap is called
117 * from Lisp PURIFY? */
118 boolean verify_after_free_heap = 0;
120 /* Should we print a note when code objects are found in the dynamic space
121 * during a heap verify? */
122 boolean verify_dynamic_code_check = 0;
124 /* Should we check code objects for fixup errors after they are transported? */
125 boolean check_code_fixups = 0;
127 /* Should we check that newly allocated regions are zero filled? */
128 boolean gencgc_zero_check = 0;
130 /* Should we check that the free space is zero filled? */
131 boolean gencgc_enable_verify_zero_fill = 0;
133 /* Should we check that free pages are zero filled during gc_free_heap
134 * called after Lisp PURIFY? */
135 boolean gencgc_zero_check_during_free_heap = 0;
137 /* When loading a core, don't do a full scan of the memory for the
138 * memory region boundaries. (Set to true by coreparse.c if the core
139 * contained a pagetable entry).
141 boolean gencgc_partial_pickup = 0;
143 /* If defined, free pages are read-protected to ensure that nothing
147 /* #define READ_PROTECT_FREE_PAGES */
151 * GC structures and variables
154 /* the total bytes allocated. These are seen by Lisp DYNAMIC-USAGE. */
155 os_vm_size_t bytes_allocated = 0;
156 os_vm_size_t auto_gc_trigger = 0;
158 /* the source and destination generations. These are set before a GC starts
160 generation_index_t from_space;
161 generation_index_t new_space;
163 /* Set to 1 when in GC */
164 boolean gc_active_p = 0;
166 /* should the GC be conservative on stack. If false (only right before
167 * saving a core), don't scan the stack / mark pages dont_move. */
168 static boolean conservative_stack = 1;
170 /* An array of page structures is allocated on gc initialization.
171 * This helps quickly map between an address its page structure.
172 * page_table_pages is set from the size of the dynamic space. */
173 page_index_t page_table_pages;
174 struct page *page_table;
176 static inline boolean page_allocated_p(page_index_t page) {
177 return (page_table[page].allocated != FREE_PAGE_FLAG);
180 static inline boolean page_no_region_p(page_index_t page) {
181 return !(page_table[page].allocated & OPEN_REGION_PAGE_FLAG);
184 static inline boolean page_allocated_no_region_p(page_index_t page) {
185 return ((page_table[page].allocated & (UNBOXED_PAGE_FLAG | BOXED_PAGE_FLAG))
186 && page_no_region_p(page));
189 static inline boolean page_free_p(page_index_t page) {
190 return (page_table[page].allocated == FREE_PAGE_FLAG);
193 static inline boolean page_boxed_p(page_index_t page) {
194 return (page_table[page].allocated & BOXED_PAGE_FLAG);
197 static inline boolean code_page_p(page_index_t page) {
198 return (page_table[page].allocated & CODE_PAGE_FLAG);
201 static inline boolean page_boxed_no_region_p(page_index_t page) {
202 return page_boxed_p(page) && page_no_region_p(page);
205 static inline boolean page_unboxed_p(page_index_t page) {
206 /* Both flags set == boxed code page */
207 return ((page_table[page].allocated & UNBOXED_PAGE_FLAG)
208 && !page_boxed_p(page));
211 static inline boolean protect_page_p(page_index_t page, generation_index_t generation) {
212 return (page_boxed_no_region_p(page)
213 && (page_table[page].bytes_used != 0)
214 && !page_table[page].dont_move
215 && (page_table[page].gen == generation));
218 /* To map addresses to page structures the address of the first page
220 static void *heap_base = NULL;
222 /* Calculate the start address for the given page number. */
224 page_address(page_index_t page_num)
226 return (heap_base + (page_num * GENCGC_CARD_BYTES));
229 /* Calculate the address where the allocation region associated with
230 * the page starts. */
232 page_region_start(page_index_t page_index)
234 return page_address(page_index)-page_table[page_index].region_start_offset;
237 /* Find the page index within the page_table for the given
238 * address. Return -1 on failure. */
240 find_page_index(void *addr)
242 if (addr >= heap_base) {
243 page_index_t index = ((pointer_sized_uint_t)addr -
244 (pointer_sized_uint_t)heap_base) / GENCGC_CARD_BYTES;
245 if (index < page_table_pages)
252 npage_bytes(page_index_t npages)
254 gc_assert(npages>=0);
255 return ((os_vm_size_t)npages)*GENCGC_CARD_BYTES;
258 /* Check that X is a higher address than Y and return offset from Y to
260 static inline os_vm_size_t
261 void_diff(void *x, void *y)
264 return (pointer_sized_uint_t)x - (pointer_sized_uint_t)y;
267 /* a structure to hold the state of a generation
269 * CAUTION: If you modify this, make sure to touch up the alien
270 * definition in src/code/gc.lisp accordingly. ...or better yes,
271 * deal with the FIXME there...
275 /* the first page that gc_alloc() checks on its next call */
276 page_index_t alloc_start_page;
278 /* the first page that gc_alloc_unboxed() checks on its next call */
279 page_index_t alloc_unboxed_start_page;
281 /* the first page that gc_alloc_large (boxed) considers on its next
282 * call. (Although it always allocates after the boxed_region.) */
283 page_index_t alloc_large_start_page;
285 /* the first page that gc_alloc_large (unboxed) considers on its
286 * next call. (Although it always allocates after the
287 * current_unboxed_region.) */
288 page_index_t alloc_large_unboxed_start_page;
290 /* the bytes allocated to this generation */
291 os_vm_size_t bytes_allocated;
293 /* the number of bytes at which to trigger a GC */
294 os_vm_size_t gc_trigger;
296 /* to calculate a new level for gc_trigger */
297 os_vm_size_t bytes_consed_between_gc;
299 /* the number of GCs since the last raise */
302 /* the number of GCs to run on the generations before raising objects to the
304 int number_of_gcs_before_promotion;
306 /* the cumulative sum of the bytes allocated to this generation. It is
307 * cleared after a GC on this generations, and update before new
308 * objects are added from a GC of a younger generation. Dividing by
309 * the bytes_allocated will give the average age of the memory in
310 * this generation since its last GC. */
311 os_vm_size_t cum_sum_bytes_allocated;
313 /* a minimum average memory age before a GC will occur helps
314 * prevent a GC when a large number of new live objects have been
315 * added, in which case a GC could be a waste of time */
316 double minimum_age_before_gc;
319 /* an array of generation structures. There needs to be one more
320 * generation structure than actual generations as the oldest
321 * generation is temporarily raised then lowered. */
322 struct generation generations[NUM_GENERATIONS];
324 /* the oldest generation that is will currently be GCed by default.
325 * Valid values are: 0, 1, ... HIGHEST_NORMAL_GENERATION
327 * The default of HIGHEST_NORMAL_GENERATION enables GC on all generations.
329 * Setting this to 0 effectively disables the generational nature of
330 * the GC. In some applications generational GC may not be useful
331 * because there are no long-lived objects.
333 * An intermediate value could be handy after moving long-lived data
334 * into an older generation so an unnecessary GC of this long-lived
335 * data can be avoided. */
336 generation_index_t gencgc_oldest_gen_to_gc = HIGHEST_NORMAL_GENERATION;
338 /* The maximum free page in the heap is maintained and used to update
339 * ALLOCATION_POINTER which is used by the room function to limit its
340 * search of the heap. XX Gencgc obviously needs to be better
341 * integrated with the Lisp code. */
342 page_index_t last_free_page;
344 #ifdef LISP_FEATURE_SB_THREAD
345 /* This lock is to prevent multiple threads from simultaneously
346 * allocating new regions which overlap each other. Note that the
347 * majority of GC is single-threaded, but alloc() may be called from
348 * >1 thread at a time and must be thread-safe. This lock must be
349 * seized before all accesses to generations[] or to parts of
350 * page_table[] that other threads may want to see */
351 static pthread_mutex_t free_pages_lock = PTHREAD_MUTEX_INITIALIZER;
352 /* This lock is used to protect non-thread-local allocation. */
353 static pthread_mutex_t allocation_lock = PTHREAD_MUTEX_INITIALIZER;
356 extern os_vm_size_t gencgc_release_granularity;
357 os_vm_size_t gencgc_release_granularity = GENCGC_RELEASE_GRANULARITY;
359 extern os_vm_size_t gencgc_alloc_granularity;
360 os_vm_size_t gencgc_alloc_granularity = GENCGC_ALLOC_GRANULARITY;
364 * miscellaneous heap functions
367 /* Count the number of pages which are write-protected within the
368 * given generation. */
370 count_write_protect_generation_pages(generation_index_t generation)
372 page_index_t i, count = 0;
374 for (i = 0; i < last_free_page; i++)
375 if (page_allocated_p(i)
376 && (page_table[i].gen == generation)
377 && (page_table[i].write_protected == 1))
382 /* Count the number of pages within the given generation. */
384 count_generation_pages(generation_index_t generation)
387 page_index_t count = 0;
389 for (i = 0; i < last_free_page; i++)
390 if (page_allocated_p(i)
391 && (page_table[i].gen == generation))
398 count_dont_move_pages(void)
401 page_index_t count = 0;
402 for (i = 0; i < last_free_page; i++) {
403 if (page_allocated_p(i)
404 && (page_table[i].dont_move != 0)) {
412 /* Work through the pages and add up the number of bytes used for the
413 * given generation. */
415 count_generation_bytes_allocated (generation_index_t gen)
418 os_vm_size_t result = 0;
419 for (i = 0; i < last_free_page; i++) {
420 if (page_allocated_p(i)
421 && (page_table[i].gen == gen))
422 result += page_table[i].bytes_used;
427 /* Return the average age of the memory in a generation. */
429 generation_average_age(generation_index_t gen)
431 if (generations[gen].bytes_allocated == 0)
435 ((double)generations[gen].cum_sum_bytes_allocated)
436 / ((double)generations[gen].bytes_allocated);
440 write_generation_stats(FILE *file)
442 generation_index_t i;
444 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
445 #define FPU_STATE_SIZE 27
446 int fpu_state[FPU_STATE_SIZE];
447 #elif defined(LISP_FEATURE_PPC)
448 #define FPU_STATE_SIZE 32
449 long long fpu_state[FPU_STATE_SIZE];
452 /* This code uses the FP instructions which may be set up for Lisp
453 * so they need to be saved and reset for C. */
456 /* Print the heap stats. */
458 " Gen StaPg UbSta LaSta LUbSt Boxed Unboxed LB LUB !move Alloc Waste Trig WP GCs Mem-age\n");
460 for (i = 0; i < SCRATCH_GENERATION; i++) {
462 page_index_t boxed_cnt = 0;
463 page_index_t unboxed_cnt = 0;
464 page_index_t large_boxed_cnt = 0;
465 page_index_t large_unboxed_cnt = 0;
466 page_index_t pinned_cnt=0;
468 for (j = 0; j < last_free_page; j++)
469 if (page_table[j].gen == i) {
471 /* Count the number of boxed pages within the given
473 if (page_boxed_p(j)) {
474 if (page_table[j].large_object)
479 if(page_table[j].dont_move) pinned_cnt++;
480 /* Count the number of unboxed pages within the given
482 if (page_unboxed_p(j)) {
483 if (page_table[j].large_object)
490 gc_assert(generations[i].bytes_allocated
491 == count_generation_bytes_allocated(i));
493 " %1d: %5ld %5ld %5ld %5ld",
495 generations[i].alloc_start_page,
496 generations[i].alloc_unboxed_start_page,
497 generations[i].alloc_large_start_page,
498 generations[i].alloc_large_unboxed_start_page);
500 " %5"PAGE_INDEX_FMT" %5"PAGE_INDEX_FMT" %5"PAGE_INDEX_FMT
501 " %5"PAGE_INDEX_FMT" %5"PAGE_INDEX_FMT,
502 boxed_cnt, unboxed_cnt, large_boxed_cnt,
503 large_unboxed_cnt, pinned_cnt);
508 " %4"PAGE_INDEX_FMT" %3d %7.4f\n",
509 generations[i].bytes_allocated,
510 (npage_bytes(count_generation_pages(i)) - generations[i].bytes_allocated),
511 generations[i].gc_trigger,
512 count_write_protect_generation_pages(i),
513 generations[i].num_gc,
514 generation_average_age(i));
516 fprintf(file," Total bytes allocated = %"OS_VM_SIZE_FMT"\n", bytes_allocated);
517 fprintf(file," Dynamic-space-size bytes = %"OS_VM_SIZE_FMT"\n", dynamic_space_size);
519 fpu_restore(fpu_state);
523 write_heap_exhaustion_report(FILE *file, long available, long requested,
524 struct thread *thread)
527 "Heap exhausted during %s: %ld bytes available, %ld requested.\n",
528 gc_active_p ? "garbage collection" : "allocation",
531 write_generation_stats(file);
532 fprintf(file, "GC control variables:\n");
533 fprintf(file, " *GC-INHIBIT* = %s\n *GC-PENDING* = %s\n",
534 SymbolValue(GC_INHIBIT,thread)==NIL ? "false" : "true",
535 (SymbolValue(GC_PENDING, thread) == T) ?
536 "true" : ((SymbolValue(GC_PENDING, thread) == NIL) ?
537 "false" : "in progress"));
538 #ifdef LISP_FEATURE_SB_THREAD
539 fprintf(file, " *STOP-FOR-GC-PENDING* = %s\n",
540 SymbolValue(STOP_FOR_GC_PENDING,thread)==NIL ? "false" : "true");
545 print_generation_stats(void)
547 write_generation_stats(stderr);
550 extern char* gc_logfile;
551 char * gc_logfile = NULL;
554 log_generation_stats(char *logfile, char *header)
557 FILE * log = fopen(logfile, "a");
559 fprintf(log, "%s\n", header);
560 write_generation_stats(log);
563 fprintf(stderr, "Could not open gc logfile: %s\n", logfile);
570 report_heap_exhaustion(long available, long requested, struct thread *th)
573 FILE * log = fopen(gc_logfile, "a");
575 write_heap_exhaustion_report(log, available, requested, th);
578 fprintf(stderr, "Could not open gc logfile: %s\n", gc_logfile);
582 /* Always to stderr as well. */
583 write_heap_exhaustion_report(stderr, available, requested, th);
587 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
588 void fast_bzero(void*, size_t); /* in <arch>-assem.S */
591 /* Zero the pages from START to END (inclusive), but use mmap/munmap instead
592 * if zeroing it ourselves, i.e. in practice give the memory back to the
593 * OS. Generally done after a large GC.
595 void zero_pages_with_mmap(page_index_t start, page_index_t end) {
597 void *addr = page_address(start), *new_addr;
598 os_vm_size_t length = npage_bytes(1+end-start);
603 gc_assert(length >= gencgc_release_granularity);
604 gc_assert((length % gencgc_release_granularity) == 0);
606 os_invalidate(addr, length);
607 new_addr = os_validate(addr, length);
608 if (new_addr == NULL || new_addr != addr) {
609 lose("remap_free_pages: page moved, 0x%08x ==> 0x%08x",
613 for (i = start; i <= end; i++) {
614 page_table[i].need_to_zero = 0;
618 /* Zero the pages from START to END (inclusive). Generally done just after
619 * a new region has been allocated.
622 zero_pages(page_index_t start, page_index_t end) {
626 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
627 fast_bzero(page_address(start), npage_bytes(1+end-start));
629 bzero(page_address(start), npage_bytes(1+end-start));
635 zero_and_mark_pages(page_index_t start, page_index_t end) {
638 zero_pages(start, end);
639 for (i = start; i <= end; i++)
640 page_table[i].need_to_zero = 0;
643 /* Zero the pages from START to END (inclusive), except for those
644 * pages that are known to already zeroed. Mark all pages in the
645 * ranges as non-zeroed.
648 zero_dirty_pages(page_index_t start, page_index_t end) {
651 for (i = start; i <= end; i++) {
652 if (!page_table[i].need_to_zero) continue;
653 for (j = i+1; (j <= end) && (page_table[j].need_to_zero); j++);
658 for (i = start; i <= end; i++) {
659 page_table[i].need_to_zero = 1;
665 * To support quick and inline allocation, regions of memory can be
666 * allocated and then allocated from with just a free pointer and a
667 * check against an end address.
669 * Since objects can be allocated to spaces with different properties
670 * e.g. boxed/unboxed, generation, ages; there may need to be many
671 * allocation regions.
673 * Each allocation region may start within a partly used page. Many
674 * features of memory use are noted on a page wise basis, e.g. the
675 * generation; so if a region starts within an existing allocated page
676 * it must be consistent with this page.
678 * During the scavenging of the newspace, objects will be transported
679 * into an allocation region, and pointers updated to point to this
680 * allocation region. It is possible that these pointers will be
681 * scavenged again before the allocation region is closed, e.g. due to
682 * trans_list which jumps all over the place to cleanup the list. It
683 * is important to be able to determine properties of all objects
684 * pointed to when scavenging, e.g to detect pointers to the oldspace.
685 * Thus it's important that the allocation regions have the correct
686 * properties set when allocated, and not just set when closed. The
687 * region allocation routines return regions with the specified
688 * properties, and grab all the pages, setting their properties
689 * appropriately, except that the amount used is not known.
691 * These regions are used to support quicker allocation using just a
692 * free pointer. The actual space used by the region is not reflected
693 * in the pages tables until it is closed. It can't be scavenged until
696 * When finished with the region it should be closed, which will
697 * update the page tables for the actual space used returning unused
698 * space. Further it may be noted in the new regions which is
699 * necessary when scavenging the newspace.
701 * Large objects may be allocated directly without an allocation
702 * region, the page tables are updated immediately.
704 * Unboxed objects don't contain pointers to other objects and so
705 * don't need scavenging. Further they can't contain pointers to
706 * younger generations so WP is not needed. By allocating pages to
707 * unboxed objects the whole page never needs scavenging or
708 * write-protecting. */
710 /* We are only using two regions at present. Both are for the current
711 * newspace generation. */
712 struct alloc_region boxed_region;
713 struct alloc_region unboxed_region;
715 /* The generation currently being allocated to. */
716 static generation_index_t gc_alloc_generation;
718 static inline page_index_t
719 generation_alloc_start_page(generation_index_t generation, int page_type_flag, int large)
722 if (UNBOXED_PAGE_FLAG == page_type_flag) {
723 return generations[generation].alloc_large_unboxed_start_page;
724 } else if (BOXED_PAGE_FLAG & page_type_flag) {
725 /* Both code and data. */
726 return generations[generation].alloc_large_start_page;
728 lose("bad page type flag: %d", page_type_flag);
731 if (UNBOXED_PAGE_FLAG == page_type_flag) {
732 return generations[generation].alloc_unboxed_start_page;
733 } else if (BOXED_PAGE_FLAG & page_type_flag) {
734 /* Both code and data. */
735 return generations[generation].alloc_start_page;
737 lose("bad page_type_flag: %d", page_type_flag);
743 set_generation_alloc_start_page(generation_index_t generation, int page_type_flag, int large,
747 if (UNBOXED_PAGE_FLAG == page_type_flag) {
748 generations[generation].alloc_large_unboxed_start_page = page;
749 } else if (BOXED_PAGE_FLAG & page_type_flag) {
750 /* Both code and data. */
751 generations[generation].alloc_large_start_page = page;
753 lose("bad page type flag: %d", page_type_flag);
756 if (UNBOXED_PAGE_FLAG == page_type_flag) {
757 generations[generation].alloc_unboxed_start_page = page;
758 } else if (BOXED_PAGE_FLAG & page_type_flag) {
759 /* Both code and data. */
760 generations[generation].alloc_start_page = page;
762 lose("bad page type flag: %d", page_type_flag);
767 /* Find a new region with room for at least the given number of bytes.
769 * It starts looking at the current generation's alloc_start_page. So
770 * may pick up from the previous region if there is enough space. This
771 * keeps the allocation contiguous when scavenging the newspace.
773 * The alloc_region should have been closed by a call to
774 * gc_alloc_update_page_tables(), and will thus be in an empty state.
776 * To assist the scavenging functions write-protected pages are not
777 * used. Free pages should not be write-protected.
779 * It is critical to the conservative GC that the start of regions be
780 * known. To help achieve this only small regions are allocated at a
783 * During scavenging, pointers may be found to within the current
784 * region and the page generation must be set so that pointers to the
785 * from space can be recognized. Therefore the generation of pages in
786 * the region are set to gc_alloc_generation. To prevent another
787 * allocation call using the same pages, all the pages in the region
788 * are allocated, although they will initially be empty.
791 gc_alloc_new_region(long nbytes, int page_type_flag, struct alloc_region *alloc_region)
793 page_index_t first_page;
794 page_index_t last_page;
795 os_vm_size_t bytes_found;
801 "/alloc_new_region for %d bytes from gen %d\n",
802 nbytes, gc_alloc_generation));
805 /* Check that the region is in a reset state. */
806 gc_assert((alloc_region->first_page == 0)
807 && (alloc_region->last_page == -1)
808 && (alloc_region->free_pointer == alloc_region->end_addr));
809 ret = thread_mutex_lock(&free_pages_lock);
811 first_page = generation_alloc_start_page(gc_alloc_generation, page_type_flag, 0);
812 last_page=gc_find_freeish_pages(&first_page, nbytes, page_type_flag);
813 bytes_found=(GENCGC_CARD_BYTES - page_table[first_page].bytes_used)
814 + npage_bytes(last_page-first_page);
816 /* Set up the alloc_region. */
817 alloc_region->first_page = first_page;
818 alloc_region->last_page = last_page;
819 alloc_region->start_addr = page_table[first_page].bytes_used
820 + page_address(first_page);
821 alloc_region->free_pointer = alloc_region->start_addr;
822 alloc_region->end_addr = alloc_region->start_addr + bytes_found;
824 /* Set up the pages. */
826 /* The first page may have already been in use. */
827 if (page_table[first_page].bytes_used == 0) {
828 page_table[first_page].allocated = page_type_flag;
829 page_table[first_page].gen = gc_alloc_generation;
830 page_table[first_page].large_object = 0;
831 page_table[first_page].region_start_offset = 0;
834 gc_assert(page_table[first_page].allocated == page_type_flag);
835 page_table[first_page].allocated |= OPEN_REGION_PAGE_FLAG;
837 gc_assert(page_table[first_page].gen == gc_alloc_generation);
838 gc_assert(page_table[first_page].large_object == 0);
840 for (i = first_page+1; i <= last_page; i++) {
841 page_table[i].allocated = page_type_flag;
842 page_table[i].gen = gc_alloc_generation;
843 page_table[i].large_object = 0;
844 /* This may not be necessary for unboxed regions (think it was
846 page_table[i].region_start_offset =
847 void_diff(page_address(i),alloc_region->start_addr);
848 page_table[i].allocated |= OPEN_REGION_PAGE_FLAG ;
850 /* Bump up last_free_page. */
851 if (last_page+1 > last_free_page) {
852 last_free_page = last_page+1;
853 /* do we only want to call this on special occasions? like for
855 set_alloc_pointer((lispobj)page_address(last_free_page));
857 ret = thread_mutex_unlock(&free_pages_lock);
860 #ifdef READ_PROTECT_FREE_PAGES
861 os_protect(page_address(first_page),
862 npage_bytes(1+last_page-first_page),
866 /* If the first page was only partial, don't check whether it's
867 * zeroed (it won't be) and don't zero it (since the parts that
868 * we're interested in are guaranteed to be zeroed).
870 if (page_table[first_page].bytes_used) {
874 zero_dirty_pages(first_page, last_page);
876 /* we can do this after releasing free_pages_lock */
877 if (gencgc_zero_check) {
879 for (p = (word_t *)alloc_region->start_addr;
880 p < (word_t *)alloc_region->end_addr; p++) {
882 lose("The new region is not zero at %p (start=%p, end=%p).\n",
883 p, alloc_region->start_addr, alloc_region->end_addr);
889 /* If the record_new_objects flag is 2 then all new regions created
892 * If it's 1 then then it is only recorded if the first page of the
893 * current region is <= new_areas_ignore_page. This helps avoid
894 * unnecessary recording when doing full scavenge pass.
896 * The new_object structure holds the page, byte offset, and size of
897 * new regions of objects. Each new area is placed in the array of
898 * these structures pointer to by new_areas. new_areas_index holds the
899 * offset into new_areas.
901 * If new_area overflows NUM_NEW_AREAS then it stops adding them. The
902 * later code must detect this and handle it, probably by doing a full
903 * scavenge of a generation. */
904 #define NUM_NEW_AREAS 512
905 static int record_new_objects = 0;
906 static page_index_t new_areas_ignore_page;
912 static struct new_area (*new_areas)[];
913 static size_t new_areas_index;
914 size_t max_new_areas;
916 /* Add a new area to new_areas. */
918 add_new_area(page_index_t first_page, size_t offset, size_t size)
920 size_t new_area_start, c, i;
922 /* Ignore if full. */
923 if (new_areas_index >= NUM_NEW_AREAS)
926 switch (record_new_objects) {
930 if (first_page > new_areas_ignore_page)
939 new_area_start = npage_bytes(first_page) + offset;
941 /* Search backwards for a prior area that this follows from. If
942 found this will save adding a new area. */
943 for (i = new_areas_index-1, c = 0; (i >= 0) && (c < 8); i--, c++) {
945 npage_bytes((*new_areas)[i].page)
946 + (*new_areas)[i].offset
947 + (*new_areas)[i].size;
949 "/add_new_area S1 %d %d %d %d\n",
950 i, c, new_area_start, area_end));*/
951 if (new_area_start == area_end) {
953 "/adding to [%d] %d %d %d with %d %d %d:\n",
955 (*new_areas)[i].page,
956 (*new_areas)[i].offset,
957 (*new_areas)[i].size,
961 (*new_areas)[i].size += size;
966 (*new_areas)[new_areas_index].page = first_page;
967 (*new_areas)[new_areas_index].offset = offset;
968 (*new_areas)[new_areas_index].size = size;
970 "/new_area %d page %d offset %d size %d\n",
971 new_areas_index, first_page, offset, size));*/
974 /* Note the max new_areas used. */
975 if (new_areas_index > max_new_areas)
976 max_new_areas = new_areas_index;
979 /* Update the tables for the alloc_region. The region may be added to
982 * When done the alloc_region is set up so that the next quick alloc
983 * will fail safely and thus a new region will be allocated. Further
984 * it is safe to try to re-update the page table of this reset
987 gc_alloc_update_page_tables(int page_type_flag, struct alloc_region *alloc_region)
990 page_index_t first_page;
991 page_index_t next_page;
992 os_vm_size_t bytes_used;
993 os_vm_size_t region_size;
994 os_vm_size_t byte_cnt;
995 page_bytes_t orig_first_page_bytes_used;
999 first_page = alloc_region->first_page;
1001 /* Catch an unused alloc_region. */
1002 if ((first_page == 0) && (alloc_region->last_page == -1))
1005 next_page = first_page+1;
1007 ret = thread_mutex_lock(&free_pages_lock);
1008 gc_assert(ret == 0);
1009 if (alloc_region->free_pointer != alloc_region->start_addr) {
1010 /* some bytes were allocated in the region */
1011 orig_first_page_bytes_used = page_table[first_page].bytes_used;
1013 gc_assert(alloc_region->start_addr ==
1014 (page_address(first_page)
1015 + page_table[first_page].bytes_used));
1017 /* All the pages used need to be updated */
1019 /* Update the first page. */
1021 /* If the page was free then set up the gen, and
1022 * region_start_offset. */
1023 if (page_table[first_page].bytes_used == 0)
1024 gc_assert(page_table[first_page].region_start_offset == 0);
1025 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
1027 gc_assert(page_table[first_page].allocated & page_type_flag);
1028 gc_assert(page_table[first_page].gen == gc_alloc_generation);
1029 gc_assert(page_table[first_page].large_object == 0);
1033 /* Calculate the number of bytes used in this page. This is not
1034 * always the number of new bytes, unless it was free. */
1036 if ((bytes_used = void_diff(alloc_region->free_pointer,
1037 page_address(first_page)))
1038 >GENCGC_CARD_BYTES) {
1039 bytes_used = GENCGC_CARD_BYTES;
1042 page_table[first_page].bytes_used = bytes_used;
1043 byte_cnt += bytes_used;
1046 /* All the rest of the pages should be free. We need to set
1047 * their region_start_offset pointer to the start of the
1048 * region, and set the bytes_used. */
1050 page_table[next_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
1051 gc_assert(page_table[next_page].allocated & page_type_flag);
1052 gc_assert(page_table[next_page].bytes_used == 0);
1053 gc_assert(page_table[next_page].gen == gc_alloc_generation);
1054 gc_assert(page_table[next_page].large_object == 0);
1056 gc_assert(page_table[next_page].region_start_offset ==
1057 void_diff(page_address(next_page),
1058 alloc_region->start_addr));
1060 /* Calculate the number of bytes used in this page. */
1062 if ((bytes_used = void_diff(alloc_region->free_pointer,
1063 page_address(next_page)))>GENCGC_CARD_BYTES) {
1064 bytes_used = GENCGC_CARD_BYTES;
1067 page_table[next_page].bytes_used = bytes_used;
1068 byte_cnt += bytes_used;
1073 region_size = void_diff(alloc_region->free_pointer,
1074 alloc_region->start_addr);
1075 bytes_allocated += region_size;
1076 generations[gc_alloc_generation].bytes_allocated += region_size;
1078 gc_assert((byte_cnt- orig_first_page_bytes_used) == region_size);
1080 /* Set the generations alloc restart page to the last page of
1082 set_generation_alloc_start_page(gc_alloc_generation, page_type_flag, 0, next_page-1);
1084 /* Add the region to the new_areas if requested. */
1085 if (BOXED_PAGE_FLAG & page_type_flag)
1086 add_new_area(first_page,orig_first_page_bytes_used, region_size);
1090 "/gc_alloc_update_page_tables update %d bytes to gen %d\n",
1092 gc_alloc_generation));
1095 /* There are no bytes allocated. Unallocate the first_page if
1096 * there are 0 bytes_used. */
1097 page_table[first_page].allocated &= ~(OPEN_REGION_PAGE_FLAG);
1098 if (page_table[first_page].bytes_used == 0)
1099 page_table[first_page].allocated = FREE_PAGE_FLAG;
1102 /* Unallocate any unused pages. */
1103 while (next_page <= alloc_region->last_page) {
1104 gc_assert(page_table[next_page].bytes_used == 0);
1105 page_table[next_page].allocated = FREE_PAGE_FLAG;
1108 ret = thread_mutex_unlock(&free_pages_lock);
1109 gc_assert(ret == 0);
1111 /* alloc_region is per-thread, we're ok to do this unlocked */
1112 gc_set_region_empty(alloc_region);
1115 static inline void *gc_quick_alloc(long nbytes);
1117 /* Allocate a possibly large object. */
1119 gc_alloc_large(long nbytes, int page_type_flag, struct alloc_region *alloc_region)
1122 page_index_t first_page, next_page, last_page;
1123 page_bytes_t orig_first_page_bytes_used;
1124 os_vm_size_t byte_cnt;
1125 os_vm_size_t bytes_used;
1128 ret = thread_mutex_lock(&free_pages_lock);
1129 gc_assert(ret == 0);
1131 first_page = generation_alloc_start_page(gc_alloc_generation, page_type_flag, 1);
1132 if (first_page <= alloc_region->last_page) {
1133 first_page = alloc_region->last_page+1;
1136 last_page=gc_find_freeish_pages(&first_page,nbytes, page_type_flag);
1138 gc_assert(first_page > alloc_region->last_page);
1140 set_generation_alloc_start_page(gc_alloc_generation, page_type_flag, 1, last_page);
1142 /* Set up the pages. */
1143 orig_first_page_bytes_used = page_table[first_page].bytes_used;
1145 /* If the first page was free then set up the gen, and
1146 * region_start_offset. */
1147 if (page_table[first_page].bytes_used == 0) {
1148 page_table[first_page].allocated = page_type_flag;
1149 page_table[first_page].gen = gc_alloc_generation;
1150 page_table[first_page].region_start_offset = 0;
1151 page_table[first_page].large_object = 1;
1154 gc_assert(page_table[first_page].allocated == page_type_flag);
1155 gc_assert(page_table[first_page].gen == gc_alloc_generation);
1156 gc_assert(page_table[first_page].large_object == 1);
1160 /* Calc. the number of bytes used in this page. This is not
1161 * always the number of new bytes, unless it was free. */
1163 if ((bytes_used = nbytes+orig_first_page_bytes_used) > GENCGC_CARD_BYTES) {
1164 bytes_used = GENCGC_CARD_BYTES;
1167 page_table[first_page].bytes_used = bytes_used;
1168 byte_cnt += bytes_used;
1170 next_page = first_page+1;
1172 /* All the rest of the pages should be free. We need to set their
1173 * region_start_offset pointer to the start of the region, and set
1174 * the bytes_used. */
1176 gc_assert(page_free_p(next_page));
1177 gc_assert(page_table[next_page].bytes_used == 0);
1178 page_table[next_page].allocated = page_type_flag;
1179 page_table[next_page].gen = gc_alloc_generation;
1180 page_table[next_page].large_object = 1;
1182 page_table[next_page].region_start_offset =
1183 npage_bytes(next_page-first_page) - orig_first_page_bytes_used;
1185 /* Calculate the number of bytes used in this page. */
1187 bytes_used=(nbytes+orig_first_page_bytes_used)-byte_cnt;
1188 if (bytes_used > GENCGC_CARD_BYTES) {
1189 bytes_used = GENCGC_CARD_BYTES;
1192 page_table[next_page].bytes_used = bytes_used;
1193 page_table[next_page].write_protected=0;
1194 page_table[next_page].dont_move=0;
1195 byte_cnt += bytes_used;
1199 gc_assert((byte_cnt-orig_first_page_bytes_used) == nbytes);
1201 bytes_allocated += nbytes;
1202 generations[gc_alloc_generation].bytes_allocated += nbytes;
1204 /* Add the region to the new_areas if requested. */
1205 if (BOXED_PAGE_FLAG & page_type_flag)
1206 add_new_area(first_page,orig_first_page_bytes_used,nbytes);
1208 /* Bump up last_free_page */
1209 if (last_page+1 > last_free_page) {
1210 last_free_page = last_page+1;
1211 set_alloc_pointer((lispobj)(page_address(last_free_page)));
1213 ret = thread_mutex_unlock(&free_pages_lock);
1214 gc_assert(ret == 0);
1216 #ifdef READ_PROTECT_FREE_PAGES
1217 os_protect(page_address(first_page),
1218 npage_bytes(1+last_page-first_page),
1222 zero_dirty_pages(first_page, last_page);
1224 return page_address(first_page);
1227 static page_index_t gencgc_alloc_start_page = -1;
1230 gc_heap_exhausted_error_or_lose (long available, long requested)
1232 struct thread *thread = arch_os_get_current_thread();
1233 /* Write basic information before doing anything else: if we don't
1234 * call to lisp this is a must, and even if we do there is always
1235 * the danger that we bounce back here before the error has been
1236 * handled, or indeed even printed.
1238 report_heap_exhaustion(available, requested, thread);
1239 if (gc_active_p || (available == 0)) {
1240 /* If we are in GC, or totally out of memory there is no way
1241 * to sanely transfer control to the lisp-side of things.
1243 lose("Heap exhausted, game over.");
1246 /* FIXME: assert free_pages_lock held */
1247 (void)thread_mutex_unlock(&free_pages_lock);
1248 gc_assert(get_pseudo_atomic_atomic(thread));
1249 clear_pseudo_atomic_atomic(thread);
1250 if (get_pseudo_atomic_interrupted(thread))
1251 do_pending_interrupt();
1252 /* Another issue is that signalling HEAP-EXHAUSTED error leads
1253 * to running user code at arbitrary places, even in a
1254 * WITHOUT-INTERRUPTS which may lead to a deadlock without
1255 * running out of the heap. So at this point all bets are
1257 if (SymbolValue(INTERRUPTS_ENABLED,thread) == NIL)
1258 corruption_warning_and_maybe_lose
1259 ("Signalling HEAP-EXHAUSTED in a WITHOUT-INTERRUPTS.");
1260 funcall2(StaticSymbolFunction(HEAP_EXHAUSTED_ERROR),
1261 alloc_number(available), alloc_number(requested));
1262 lose("HEAP-EXHAUSTED-ERROR fell through");
1267 gc_find_freeish_pages(page_index_t *restart_page_ptr, long bytes,
1270 page_index_t most_bytes_found_from = 0, most_bytes_found_to = 0;
1271 page_index_t first_page, last_page, restart_page = *restart_page_ptr;
1272 os_vm_size_t nbytes = bytes;
1273 os_vm_size_t nbytes_goal = nbytes;
1274 os_vm_size_t bytes_found = 0;
1275 os_vm_size_t most_bytes_found = 0;
1276 boolean small_object = nbytes < GENCGC_CARD_BYTES;
1277 /* FIXME: assert(free_pages_lock is held); */
1279 if (nbytes_goal < gencgc_alloc_granularity)
1280 nbytes_goal = gencgc_alloc_granularity;
1282 /* Toggled by gc_and_save for heap compaction, normally -1. */
1283 if (gencgc_alloc_start_page != -1) {
1284 restart_page = gencgc_alloc_start_page;
1287 /* FIXME: This is on bytes instead of nbytes pending cleanup of
1288 * long from the interface. */
1289 gc_assert(bytes>=0);
1290 /* Search for a page with at least nbytes of space. We prefer
1291 * not to split small objects on multiple pages, to reduce the
1292 * number of contiguous allocation regions spaning multiple
1293 * pages: this helps avoid excessive conservativism.
1295 * For other objects, we guarantee that they start on their own
1298 first_page = restart_page;
1299 while (first_page < page_table_pages) {
1301 if (page_free_p(first_page)) {
1302 gc_assert(0 == page_table[first_page].bytes_used);
1303 bytes_found = GENCGC_CARD_BYTES;
1304 } else if (small_object &&
1305 (page_table[first_page].allocated == page_type_flag) &&
1306 (page_table[first_page].large_object == 0) &&
1307 (page_table[first_page].gen == gc_alloc_generation) &&
1308 (page_table[first_page].write_protected == 0) &&
1309 (page_table[first_page].dont_move == 0)) {
1310 bytes_found = GENCGC_CARD_BYTES - page_table[first_page].bytes_used;
1311 if (bytes_found < nbytes) {
1312 if (bytes_found > most_bytes_found)
1313 most_bytes_found = bytes_found;
1322 gc_assert(page_table[first_page].write_protected == 0);
1323 for (last_page = first_page+1;
1324 ((last_page < page_table_pages) &&
1325 page_free_p(last_page) &&
1326 (bytes_found < nbytes_goal));
1328 bytes_found += GENCGC_CARD_BYTES;
1329 gc_assert(0 == page_table[last_page].bytes_used);
1330 gc_assert(0 == page_table[last_page].write_protected);
1333 if (bytes_found > most_bytes_found) {
1334 most_bytes_found = bytes_found;
1335 most_bytes_found_from = first_page;
1336 most_bytes_found_to = last_page;
1338 if (bytes_found >= nbytes_goal)
1341 first_page = last_page;
1344 bytes_found = most_bytes_found;
1345 restart_page = first_page + 1;
1347 /* Check for a failure */
1348 if (bytes_found < nbytes) {
1349 gc_assert(restart_page >= page_table_pages);
1350 gc_heap_exhausted_error_or_lose(most_bytes_found, nbytes);
1353 gc_assert(most_bytes_found_to);
1354 *restart_page_ptr = most_bytes_found_from;
1355 return most_bytes_found_to-1;
1358 /* Allocate bytes. All the rest of the special-purpose allocation
1359 * functions will eventually call this */
1362 gc_alloc_with_region(long nbytes,int page_type_flag, struct alloc_region *my_region,
1365 void *new_free_pointer;
1367 if (nbytes>=large_object_size)
1368 return gc_alloc_large(nbytes, page_type_flag, my_region);
1370 /* Check whether there is room in the current alloc region. */
1371 new_free_pointer = my_region->free_pointer + nbytes;
1373 /* fprintf(stderr, "alloc %d bytes from %p to %p\n", nbytes,
1374 my_region->free_pointer, new_free_pointer); */
1376 if (new_free_pointer <= my_region->end_addr) {
1377 /* If so then allocate from the current alloc region. */
1378 void *new_obj = my_region->free_pointer;
1379 my_region->free_pointer = new_free_pointer;
1381 /* Unless a `quick' alloc was requested, check whether the
1382 alloc region is almost empty. */
1384 void_diff(my_region->end_addr,my_region->free_pointer) <= 32) {
1385 /* If so, finished with the current region. */
1386 gc_alloc_update_page_tables(page_type_flag, my_region);
1387 /* Set up a new region. */
1388 gc_alloc_new_region(32 /*bytes*/, page_type_flag, my_region);
1391 return((void *)new_obj);
1394 /* Else not enough free space in the current region: retry with a
1397 gc_alloc_update_page_tables(page_type_flag, my_region);
1398 gc_alloc_new_region(nbytes, page_type_flag, my_region);
1399 return gc_alloc_with_region(nbytes, page_type_flag, my_region,0);
1402 /* these are only used during GC: all allocation from the mutator calls
1403 * alloc() -> gc_alloc_with_region() with the appropriate per-thread
1406 static inline void *
1407 gc_quick_alloc(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 /* Copy a large object. If the object is in a large object region then
1425 * it is simply promoted, else it is copied. If it's large enough then
1426 * it's copied to a large object region.
1428 * Bignums and vectors may have shrunk. If the object is not copied
1429 * the space needs to be reclaimed, and the page_tables corrected. */
1431 general_copy_large_object(lispobj object, long nwords, boolean boxedp)
1435 page_index_t first_page;
1437 gc_assert(is_lisp_pointer(object));
1438 gc_assert(from_space_p(object));
1439 gc_assert((nwords & 0x01) == 0);
1441 if ((nwords > 1024*1024) && gencgc_verbose) {
1442 FSHOW((stderr, "/general_copy_large_object: %d bytes\n",
1443 nwords*N_WORD_BYTES));
1446 /* Check whether it's a large object. */
1447 first_page = find_page_index((void *)object);
1448 gc_assert(first_page >= 0);
1450 if (page_table[first_page].large_object) {
1451 /* Promote the object. Note: Unboxed objects may have been
1452 * allocated to a BOXED region so it may be necessary to
1453 * change the region to UNBOXED. */
1454 os_vm_size_t remaining_bytes;
1455 os_vm_size_t bytes_freed;
1456 page_index_t next_page;
1457 page_bytes_t old_bytes_used;
1459 /* FIXME: This comment is somewhat stale.
1461 * Note: Any page write-protection must be removed, else a
1462 * later scavenge_newspace may incorrectly not scavenge these
1463 * pages. This would not be necessary if they are added to the
1464 * new areas, but let's do it for them all (they'll probably
1465 * be written anyway?). */
1467 gc_assert(page_table[first_page].region_start_offset == 0);
1468 next_page = first_page;
1469 remaining_bytes = nwords*N_WORD_BYTES;
1471 while (remaining_bytes > GENCGC_CARD_BYTES) {
1472 gc_assert(page_table[next_page].gen == from_space);
1473 gc_assert(page_table[next_page].large_object);
1474 gc_assert(page_table[next_page].region_start_offset ==
1475 npage_bytes(next_page-first_page));
1476 gc_assert(page_table[next_page].bytes_used == GENCGC_CARD_BYTES);
1477 /* Should have been unprotected by unprotect_oldspace()
1478 * for boxed objects, and after promotion unboxed ones
1479 * should not be on protected pages at all. */
1480 gc_assert(!page_table[next_page].write_protected);
1483 gc_assert(page_boxed_p(next_page));
1485 gc_assert(page_allocated_no_region_p(next_page));
1486 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1488 page_table[next_page].gen = new_space;
1490 remaining_bytes -= GENCGC_CARD_BYTES;
1494 /* Now only one page remains, but the object may have shrunk so
1495 * there may be more unused pages which will be freed. */
1497 /* Object may have shrunk but shouldn't have grown - check. */
1498 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
1500 page_table[next_page].gen = new_space;
1503 gc_assert(page_boxed_p(next_page));
1505 page_table[next_page].allocated = UNBOXED_PAGE_FLAG;
1507 /* Adjust the bytes_used. */
1508 old_bytes_used = page_table[next_page].bytes_used;
1509 page_table[next_page].bytes_used = remaining_bytes;
1511 bytes_freed = old_bytes_used - remaining_bytes;
1513 /* Free any remaining pages; needs care. */
1515 while ((old_bytes_used == GENCGC_CARD_BYTES) &&
1516 (page_table[next_page].gen == from_space) &&
1517 /* FIXME: It is not obvious to me why this is necessary
1518 * as a loop condition: it seems to me that the
1519 * region_start_offset test should be sufficient, but
1520 * experimentally that is not the case. --NS
1523 page_boxed_p(next_page) :
1524 page_allocated_no_region_p(next_page)) &&
1525 page_table[next_page].large_object &&
1526 (page_table[next_page].region_start_offset ==
1527 npage_bytes(next_page - first_page))) {
1528 /* Checks out OK, free the page. Don't need to both zeroing
1529 * pages as this should have been done before shrinking the
1530 * object. These pages shouldn't be write-protected, even if
1531 * boxed they should be zero filled. */
1532 gc_assert(page_table[next_page].write_protected == 0);
1534 old_bytes_used = page_table[next_page].bytes_used;
1535 page_table[next_page].allocated = FREE_PAGE_FLAG;
1536 page_table[next_page].bytes_used = 0;
1537 bytes_freed += old_bytes_used;
1541 if ((bytes_freed > 0) && gencgc_verbose) {
1543 "/general_copy_large_object bytes_freed=%"OS_VM_SIZE_FMT"\n",
1547 generations[from_space].bytes_allocated -= nwords*N_WORD_BYTES
1549 generations[new_space].bytes_allocated += nwords*N_WORD_BYTES;
1550 bytes_allocated -= bytes_freed;
1552 /* Add the region to the new_areas if requested. */
1554 add_new_area(first_page,0,nwords*N_WORD_BYTES);
1559 /* Get tag of object. */
1560 tag = lowtag_of(object);
1562 /* Allocate space. */
1563 new = gc_general_alloc(nwords*N_WORD_BYTES,
1564 (boxedp ? BOXED_PAGE_FLAG : UNBOXED_PAGE_FLAG),
1567 /* Copy the object. */
1568 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1570 /* Return Lisp pointer of new object. */
1571 return ((lispobj) new) | tag;
1576 copy_large_object(lispobj object, long nwords)
1578 return general_copy_large_object(object, nwords, 1);
1582 copy_large_unboxed_object(lispobj object, long nwords)
1584 return general_copy_large_object(object, nwords, 0);
1587 /* to copy unboxed objects */
1589 copy_unboxed_object(lispobj object, long nwords)
1594 gc_assert(is_lisp_pointer(object));
1595 gc_assert(from_space_p(object));
1596 gc_assert((nwords & 0x01) == 0);
1598 /* Get tag of object. */
1599 tag = lowtag_of(object);
1601 /* Allocate space. */
1602 new = gc_quick_alloc_unboxed(nwords*N_WORD_BYTES);
1604 memcpy(new,native_pointer(object),nwords*N_WORD_BYTES);
1606 /* Return Lisp pointer of new object. */
1607 return ((lispobj) new) | tag;
1612 * code and code-related objects
1615 static lispobj trans_fun_header(lispobj object);
1616 static lispobj trans_boxed(lispobj object);
1619 /* Scan a x86 compiled code object, looking for possible fixups that
1620 * have been missed after a move.
1622 * Two types of fixups are needed:
1623 * 1. Absolute fixups to within the code object.
1624 * 2. Relative fixups to outside the code object.
1626 * Currently only absolute fixups to the constant vector, or to the
1627 * code area are checked. */
1629 sniff_code_object(struct code *code, unsigned long displacement)
1631 #ifdef LISP_FEATURE_X86
1632 long nheader_words, ncode_words, nwords;
1634 void *constants_start_addr = NULL, *constants_end_addr;
1635 void *code_start_addr, *code_end_addr;
1636 int fixup_found = 0;
1638 if (!check_code_fixups)
1641 FSHOW((stderr, "/sniffing code: %p, %lu\n", code, displacement));
1643 ncode_words = fixnum_value(code->code_size);
1644 nheader_words = HeaderValue(*(lispobj *)code);
1645 nwords = ncode_words + nheader_words;
1647 constants_start_addr = (void *)code + 5*N_WORD_BYTES;
1648 constants_end_addr = (void *)code + nheader_words*N_WORD_BYTES;
1649 code_start_addr = (void *)code + nheader_words*N_WORD_BYTES;
1650 code_end_addr = (void *)code + nwords*N_WORD_BYTES;
1652 /* Work through the unboxed code. */
1653 for (p = code_start_addr; p < code_end_addr; p++) {
1654 void *data = *(void **)p;
1655 unsigned d1 = *((unsigned char *)p - 1);
1656 unsigned d2 = *((unsigned char *)p - 2);
1657 unsigned d3 = *((unsigned char *)p - 3);
1658 unsigned d4 = *((unsigned char *)p - 4);
1660 unsigned d5 = *((unsigned char *)p - 5);
1661 unsigned d6 = *((unsigned char *)p - 6);
1664 /* Check for code references. */
1665 /* Check for a 32 bit word that looks like an absolute
1666 reference to within the code adea of the code object. */
1667 if ((data >= (code_start_addr-displacement))
1668 && (data < (code_end_addr-displacement))) {
1669 /* function header */
1671 && (((unsigned)p - 4 - 4*HeaderValue(*((unsigned *)p-1))) ==
1673 /* Skip the function header */
1677 /* the case of PUSH imm32 */
1681 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1682 p, d6, d5, d4, d3, d2, d1, data));
1683 FSHOW((stderr, "/PUSH $0x%.8x\n", data));
1685 /* the case of MOV [reg-8],imm32 */
1687 && (d2==0x40 || d2==0x41 || d2==0x42 || d2==0x43
1688 || d2==0x45 || d2==0x46 || d2==0x47)
1692 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1693 p, d6, d5, d4, d3, d2, d1, data));
1694 FSHOW((stderr, "/MOV [reg-8],$0x%.8x\n", data));
1696 /* the case of LEA reg,[disp32] */
1697 if ((d2 == 0x8d) && ((d1 & 0xc7) == 5)) {
1700 "/code ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1701 p, d6, d5, d4, d3, d2, d1, data));
1702 FSHOW((stderr,"/LEA reg,[$0x%.8x]\n", data));
1706 /* Check for constant references. */
1707 /* Check for a 32 bit word that looks like an absolute
1708 reference to within the constant vector. Constant references
1710 if ((data >= (constants_start_addr-displacement))
1711 && (data < (constants_end_addr-displacement))
1712 && (((unsigned)data & 0x3) == 0)) {
1717 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1718 p, d6, d5, d4, d3, d2, d1, data));
1719 FSHOW((stderr,"/MOV eax,0x%.8x\n", data));
1722 /* the case of MOV m32,EAX */
1726 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1727 p, d6, d5, d4, d3, d2, d1, data));
1728 FSHOW((stderr, "/MOV 0x%.8x,eax\n", data));
1731 /* the case of CMP m32,imm32 */
1732 if ((d1 == 0x3d) && (d2 == 0x81)) {
1735 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1736 p, d6, d5, d4, d3, d2, d1, data));
1738 FSHOW((stderr, "/CMP 0x%.8x,immed32\n", data));
1741 /* Check for a mod=00, r/m=101 byte. */
1742 if ((d1 & 0xc7) == 5) {
1747 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1748 p, d6, d5, d4, d3, d2, d1, data));
1749 FSHOW((stderr,"/CMP 0x%.8x,reg\n", data));
1751 /* the case of CMP reg32,m32 */
1755 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1756 p, d6, d5, d4, d3, d2, d1, data));
1757 FSHOW((stderr, "/CMP reg32,0x%.8x\n", data));
1759 /* the case of MOV m32,reg32 */
1763 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1764 p, d6, d5, d4, d3, d2, d1, data));
1765 FSHOW((stderr, "/MOV 0x%.8x,reg32\n", data));
1767 /* the case of MOV reg32,m32 */
1771 "/abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1772 p, d6, d5, d4, d3, d2, d1, data));
1773 FSHOW((stderr, "/MOV reg32,0x%.8x\n", data));
1775 /* the case of LEA reg32,m32 */
1779 "abs const ref @%x: %.2x %.2x %.2x %.2x %.2x %.2x (%.8x)\n",
1780 p, d6, d5, d4, d3, d2, d1, data));
1781 FSHOW((stderr, "/LEA reg32,0x%.8x\n", data));
1787 /* If anything was found, print some information on the code
1791 "/compiled code object at %x: header words = %d, code words = %d\n",
1792 code, nheader_words, ncode_words));
1794 "/const start = %x, end = %x\n",
1795 constants_start_addr, constants_end_addr));
1797 "/code start = %x, end = %x\n",
1798 code_start_addr, code_end_addr));
1804 gencgc_apply_code_fixups(struct code *old_code, struct code *new_code)
1806 /* x86-64 uses pc-relative addressing instead of this kludge */
1807 #ifndef LISP_FEATURE_X86_64
1808 long nheader_words, ncode_words, nwords;
1809 void *constants_start_addr, *constants_end_addr;
1810 void *code_start_addr, *code_end_addr;
1811 lispobj fixups = NIL;
1812 unsigned long displacement =
1813 (unsigned long)new_code - (unsigned long)old_code;
1814 struct vector *fixups_vector;
1816 ncode_words = fixnum_value(new_code->code_size);
1817 nheader_words = HeaderValue(*(lispobj *)new_code);
1818 nwords = ncode_words + nheader_words;
1820 "/compiled code object at %x: header words = %d, code words = %d\n",
1821 new_code, nheader_words, ncode_words)); */
1822 constants_start_addr = (void *)new_code + 5*N_WORD_BYTES;
1823 constants_end_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1824 code_start_addr = (void *)new_code + nheader_words*N_WORD_BYTES;
1825 code_end_addr = (void *)new_code + nwords*N_WORD_BYTES;
1828 "/const start = %x, end = %x\n",
1829 constants_start_addr,constants_end_addr));
1831 "/code start = %x; end = %x\n",
1832 code_start_addr,code_end_addr));
1835 /* The first constant should be a pointer to the fixups for this
1836 code objects. Check. */
1837 fixups = new_code->constants[0];
1839 /* It will be 0 or the unbound-marker if there are no fixups (as
1840 * will be the case if the code object has been purified, for
1841 * example) and will be an other pointer if it is valid. */
1842 if ((fixups == 0) || (fixups == UNBOUND_MARKER_WIDETAG) ||
1843 !is_lisp_pointer(fixups)) {
1844 /* Check for possible errors. */
1845 if (check_code_fixups)
1846 sniff_code_object(new_code, displacement);
1851 fixups_vector = (struct vector *)native_pointer(fixups);
1853 /* Could be pointing to a forwarding pointer. */
1854 /* FIXME is this always in from_space? if so, could replace this code with
1855 * forwarding_pointer_p/forwarding_pointer_value */
1856 if (is_lisp_pointer(fixups) &&
1857 (find_page_index((void*)fixups_vector) != -1) &&
1858 (fixups_vector->header == 0x01)) {
1859 /* If so, then follow it. */
1860 /*SHOW("following pointer to a forwarding pointer");*/
1862 (struct vector *)native_pointer((lispobj)fixups_vector->length);
1865 /*SHOW("got fixups");*/
1867 if (widetag_of(fixups_vector->header) == SIMPLE_ARRAY_WORD_WIDETAG) {
1868 /* Got the fixups for the code block. Now work through the vector,
1869 and apply a fixup at each address. */
1870 long length = fixnum_value(fixups_vector->length);
1872 for (i = 0; i < length; i++) {
1873 unsigned long offset = fixups_vector->data[i];
1874 /* Now check the current value of offset. */
1875 unsigned long old_value =
1876 *(unsigned long *)((unsigned long)code_start_addr + offset);
1878 /* If it's within the old_code object then it must be an
1879 * absolute fixup (relative ones are not saved) */
1880 if ((old_value >= (unsigned long)old_code)
1881 && (old_value < ((unsigned long)old_code
1882 + nwords*N_WORD_BYTES)))
1883 /* So add the dispacement. */
1884 *(unsigned long *)((unsigned long)code_start_addr + offset) =
1885 old_value + displacement;
1887 /* It is outside the old code object so it must be a
1888 * relative fixup (absolute fixups are not saved). So
1889 * subtract the displacement. */
1890 *(unsigned long *)((unsigned long)code_start_addr + offset) =
1891 old_value - displacement;
1894 /* This used to just print a note to stderr, but a bogus fixup seems to
1895 * indicate real heap corruption, so a hard hailure is in order. */
1896 lose("fixup vector %p has a bad widetag: %d\n",
1897 fixups_vector, widetag_of(fixups_vector->header));
1900 /* Check for possible errors. */
1901 if (check_code_fixups) {
1902 sniff_code_object(new_code,displacement);
1909 trans_boxed_large(lispobj object)
1912 unsigned long length;
1914 gc_assert(is_lisp_pointer(object));
1916 header = *((lispobj *) native_pointer(object));
1917 length = HeaderValue(header) + 1;
1918 length = CEILING(length, 2);
1920 return copy_large_object(object, length);
1923 /* Doesn't seem to be used, delete it after the grace period. */
1926 trans_unboxed_large(lispobj object)
1929 unsigned long length;
1931 gc_assert(is_lisp_pointer(object));
1933 header = *((lispobj *) native_pointer(object));
1934 length = HeaderValue(header) + 1;
1935 length = CEILING(length, 2);
1937 return copy_large_unboxed_object(object, length);
1945 /* XX This is a hack adapted from cgc.c. These don't work too
1946 * efficiently with the gencgc as a list of the weak pointers is
1947 * maintained within the objects which causes writes to the pages. A
1948 * limited attempt is made to avoid unnecessary writes, but this needs
1950 #define WEAK_POINTER_NWORDS \
1951 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
1954 scav_weak_pointer(lispobj *where, lispobj object)
1956 /* Since we overwrite the 'next' field, we have to make
1957 * sure not to do so for pointers already in the list.
1958 * Instead of searching the list of weak_pointers each
1959 * time, we ensure that next is always NULL when the weak
1960 * pointer isn't in the list, and not NULL otherwise.
1961 * Since we can't use NULL to denote end of list, we
1962 * use a pointer back to the same weak_pointer.
1964 struct weak_pointer * wp = (struct weak_pointer*)where;
1966 if (NULL == wp->next) {
1967 wp->next = weak_pointers;
1969 if (NULL == wp->next)
1973 /* Do not let GC scavenge the value slot of the weak pointer.
1974 * (That is why it is a weak pointer.) */
1976 return WEAK_POINTER_NWORDS;
1981 search_read_only_space(void *pointer)
1983 lispobj *start = (lispobj *) READ_ONLY_SPACE_START;
1984 lispobj *end = (lispobj *) SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
1985 if ((pointer < (void *)start) || (pointer >= (void *)end))
1987 return (gc_search_space(start,
1988 (((lispobj *)pointer)+2)-start,
1989 (lispobj *) pointer));
1993 search_static_space(void *pointer)
1995 lispobj *start = (lispobj *)STATIC_SPACE_START;
1996 lispobj *end = (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
1997 if ((pointer < (void *)start) || (pointer >= (void *)end))
1999 return (gc_search_space(start,
2000 (((lispobj *)pointer)+2)-start,
2001 (lispobj *) pointer));
2004 /* a faster version for searching the dynamic space. This will work even
2005 * if the object is in a current allocation region. */
2007 search_dynamic_space(void *pointer)
2009 page_index_t page_index = find_page_index(pointer);
2012 /* The address may be invalid, so do some checks. */
2013 if ((page_index == -1) || page_free_p(page_index))
2015 start = (lispobj *)page_region_start(page_index);
2016 return (gc_search_space(start,
2017 (((lispobj *)pointer)+2)-start,
2018 (lispobj *)pointer));
2021 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2023 /* Is there any possibility that pointer is a valid Lisp object
2024 * reference, and/or something else (e.g. subroutine call return
2025 * address) which should prevent us from moving the referred-to thing?
2026 * This is called from preserve_pointers() */
2028 possibly_valid_dynamic_space_pointer(lispobj *pointer)
2030 lispobj *start_addr;
2032 /* Find the object start address. */
2033 if ((start_addr = search_dynamic_space(pointer)) == NULL) {
2037 return looks_like_valid_lisp_pointer_p(pointer, start_addr);
2040 #endif // defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2042 /* Adjust large bignum and vector objects. This will adjust the
2043 * allocated region if the size has shrunk, and move unboxed objects
2044 * into unboxed pages. The pages are not promoted here, and the
2045 * promoted region is not added to the new_regions; this is really
2046 * only designed to be called from preserve_pointer(). Shouldn't fail
2047 * if this is missed, just may delay the moving of objects to unboxed
2048 * pages, and the freeing of pages. */
2050 maybe_adjust_large_object(lispobj *where)
2052 page_index_t first_page;
2053 page_index_t next_page;
2056 unsigned long remaining_bytes;
2057 unsigned long bytes_freed;
2058 unsigned long old_bytes_used;
2062 /* Check whether it's a vector or bignum object. */
2063 switch (widetag_of(where[0])) {
2064 case SIMPLE_VECTOR_WIDETAG:
2065 boxed = BOXED_PAGE_FLAG;
2067 case BIGNUM_WIDETAG:
2068 case SIMPLE_BASE_STRING_WIDETAG:
2069 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
2070 case SIMPLE_CHARACTER_STRING_WIDETAG:
2072 case SIMPLE_BIT_VECTOR_WIDETAG:
2073 case SIMPLE_ARRAY_NIL_WIDETAG:
2074 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
2075 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
2076 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
2077 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
2078 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
2079 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
2081 case SIMPLE_ARRAY_UNSIGNED_FIXNUM_WIDETAG:
2083 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
2084 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
2085 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
2086 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
2088 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
2089 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
2091 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
2092 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
2094 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
2095 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
2098 case SIMPLE_ARRAY_FIXNUM_WIDETAG:
2100 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
2101 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
2103 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
2104 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
2106 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
2107 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
2108 #ifdef SIMPLE_ARRAY_LONG_FLOAT_WIDETAG
2109 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
2111 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
2112 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
2114 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
2115 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
2117 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
2118 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
2120 boxed = UNBOXED_PAGE_FLAG;
2126 /* Find its current size. */
2127 nwords = (sizetab[widetag_of(where[0])])(where);
2129 first_page = find_page_index((void *)where);
2130 gc_assert(first_page >= 0);
2132 /* Note: Any page write-protection must be removed, else a later
2133 * scavenge_newspace may incorrectly not scavenge these pages.
2134 * This would not be necessary if they are added to the new areas,
2135 * but lets do it for them all (they'll probably be written
2138 gc_assert(page_table[first_page].region_start_offset == 0);
2140 next_page = first_page;
2141 remaining_bytes = nwords*N_WORD_BYTES;
2142 while (remaining_bytes > GENCGC_CARD_BYTES) {
2143 gc_assert(page_table[next_page].gen == from_space);
2144 gc_assert(page_allocated_no_region_p(next_page));
2145 gc_assert(page_table[next_page].large_object);
2146 gc_assert(page_table[next_page].region_start_offset ==
2147 npage_bytes(next_page-first_page));
2148 gc_assert(page_table[next_page].bytes_used == GENCGC_CARD_BYTES);
2150 page_table[next_page].allocated = boxed;
2152 /* Shouldn't be write-protected at this stage. Essential that the
2154 gc_assert(!page_table[next_page].write_protected);
2155 remaining_bytes -= GENCGC_CARD_BYTES;
2159 /* Now only one page remains, but the object may have shrunk so
2160 * there may be more unused pages which will be freed. */
2162 /* Object may have shrunk but shouldn't have grown - check. */
2163 gc_assert(page_table[next_page].bytes_used >= remaining_bytes);
2165 page_table[next_page].allocated = boxed;
2166 gc_assert(page_table[next_page].allocated ==
2167 page_table[first_page].allocated);
2169 /* Adjust the bytes_used. */
2170 old_bytes_used = page_table[next_page].bytes_used;
2171 page_table[next_page].bytes_used = remaining_bytes;
2173 bytes_freed = old_bytes_used - remaining_bytes;
2175 /* Free any remaining pages; needs care. */
2177 while ((old_bytes_used == GENCGC_CARD_BYTES) &&
2178 (page_table[next_page].gen == from_space) &&
2179 page_allocated_no_region_p(next_page) &&
2180 page_table[next_page].large_object &&
2181 (page_table[next_page].region_start_offset ==
2182 npage_bytes(next_page - first_page))) {
2183 /* It checks out OK, free the page. We don't need to both zeroing
2184 * pages as this should have been done before shrinking the
2185 * object. These pages shouldn't be write protected as they
2186 * should be zero filled. */
2187 gc_assert(page_table[next_page].write_protected == 0);
2189 old_bytes_used = page_table[next_page].bytes_used;
2190 page_table[next_page].allocated = FREE_PAGE_FLAG;
2191 page_table[next_page].bytes_used = 0;
2192 bytes_freed += old_bytes_used;
2196 if ((bytes_freed > 0) && gencgc_verbose) {
2198 "/maybe_adjust_large_object() freed %d\n",
2202 generations[from_space].bytes_allocated -= bytes_freed;
2203 bytes_allocated -= bytes_freed;
2208 /* Take a possible pointer to a Lisp object and mark its page in the
2209 * page_table so that it will not be relocated during a GC.
2211 * This involves locating the page it points to, then backing up to
2212 * the start of its region, then marking all pages dont_move from there
2213 * up to the first page that's not full or has a different generation
2215 * It is assumed that all the page static flags have been cleared at
2216 * the start of a GC.
2218 * It is also assumed that the current gc_alloc() region has been
2219 * flushed and the tables updated. */
2222 preserve_pointer(void *addr)
2224 page_index_t addr_page_index = find_page_index(addr);
2225 page_index_t first_page;
2227 unsigned int region_allocation;
2229 /* quick check 1: Address is quite likely to have been invalid. */
2230 if ((addr_page_index == -1)
2231 || page_free_p(addr_page_index)
2232 || (page_table[addr_page_index].bytes_used == 0)
2233 || (page_table[addr_page_index].gen != from_space)
2234 /* Skip if already marked dont_move. */
2235 || (page_table[addr_page_index].dont_move != 0))
2237 gc_assert(!(page_table[addr_page_index].allocated&OPEN_REGION_PAGE_FLAG));
2238 /* (Now that we know that addr_page_index is in range, it's
2239 * safe to index into page_table[] with it.) */
2240 region_allocation = page_table[addr_page_index].allocated;
2242 /* quick check 2: Check the offset within the page.
2245 if (((unsigned long)addr & (GENCGC_CARD_BYTES - 1)) >
2246 page_table[addr_page_index].bytes_used)
2249 /* Filter out anything which can't be a pointer to a Lisp object
2250 * (or, as a special case which also requires dont_move, a return
2251 * address referring to something in a CodeObject). This is
2252 * expensive but important, since it vastly reduces the
2253 * probability that random garbage will be bogusly interpreted as
2254 * a pointer which prevents a page from moving.
2256 * This only needs to happen on x86oids, where this is used for
2257 * conservative roots. Non-x86oid systems only ever call this
2258 * function on known-valid lisp objects. */
2259 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
2260 if (!(code_page_p(addr_page_index)
2261 || (is_lisp_pointer((lispobj)addr) &&
2262 possibly_valid_dynamic_space_pointer(addr))))
2266 /* Find the beginning of the region. Note that there may be
2267 * objects in the region preceding the one that we were passed a
2268 * pointer to: if this is the case, we will write-protect all the
2269 * previous objects' pages too. */
2272 /* I think this'd work just as well, but without the assertions.
2273 * -dan 2004.01.01 */
2274 first_page = find_page_index(page_region_start(addr_page_index))
2276 first_page = addr_page_index;
2277 while (page_table[first_page].region_start_offset != 0) {
2279 /* Do some checks. */
2280 gc_assert(page_table[first_page].bytes_used == GENCGC_CARD_BYTES);
2281 gc_assert(page_table[first_page].gen == from_space);
2282 gc_assert(page_table[first_page].allocated == region_allocation);
2286 /* Adjust any large objects before promotion as they won't be
2287 * copied after promotion. */
2288 if (page_table[first_page].large_object) {
2289 maybe_adjust_large_object(page_address(first_page));
2290 /* If a large object has shrunk then addr may now point to a
2291 * free area in which case it's ignored here. Note it gets
2292 * through the valid pointer test above because the tail looks
2294 if (page_free_p(addr_page_index)
2295 || (page_table[addr_page_index].bytes_used == 0)
2296 /* Check the offset within the page. */
2297 || (((unsigned long)addr & (GENCGC_CARD_BYTES - 1))
2298 > page_table[addr_page_index].bytes_used)) {
2300 "weird? ignore ptr 0x%x to freed area of large object\n",
2304 /* It may have moved to unboxed pages. */
2305 region_allocation = page_table[first_page].allocated;
2308 /* Now work forward until the end of this contiguous area is found,
2309 * marking all pages as dont_move. */
2310 for (i = first_page; ;i++) {
2311 gc_assert(page_table[i].allocated == region_allocation);
2313 /* Mark the page static. */
2314 page_table[i].dont_move = 1;
2316 /* Move the page to the new_space. XX I'd rather not do this
2317 * but the GC logic is not quite able to copy with the static
2318 * pages remaining in the from space. This also requires the
2319 * generation bytes_allocated counters be updated. */
2320 page_table[i].gen = new_space;
2321 generations[new_space].bytes_allocated += page_table[i].bytes_used;
2322 generations[from_space].bytes_allocated -= page_table[i].bytes_used;
2324 /* It is essential that the pages are not write protected as
2325 * they may have pointers into the old-space which need
2326 * scavenging. They shouldn't be write protected at this
2328 gc_assert(!page_table[i].write_protected);
2330 /* Check whether this is the last page in this contiguous block.. */
2331 if ((page_table[i].bytes_used < GENCGC_CARD_BYTES)
2332 /* ..or it is CARD_BYTES and is the last in the block */
2334 || (page_table[i+1].bytes_used == 0) /* next page free */
2335 || (page_table[i+1].gen != from_space) /* diff. gen */
2336 || (page_table[i+1].region_start_offset == 0))
2340 /* Check that the page is now static. */
2341 gc_assert(page_table[addr_page_index].dont_move != 0);
2344 /* If the given page is not write-protected, then scan it for pointers
2345 * to younger generations or the top temp. generation, if no
2346 * suspicious pointers are found then the page is write-protected.
2348 * Care is taken to check for pointers to the current gc_alloc()
2349 * region if it is a younger generation or the temp. generation. This
2350 * frees the caller from doing a gc_alloc_update_page_tables(). Actually
2351 * the gc_alloc_generation does not need to be checked as this is only
2352 * called from scavenge_generation() when the gc_alloc generation is
2353 * younger, so it just checks if there is a pointer to the current
2356 * We return 1 if the page was write-protected, else 0. */
2358 update_page_write_prot(page_index_t page)
2360 generation_index_t gen = page_table[page].gen;
2363 void **page_addr = (void **)page_address(page);
2364 long num_words = page_table[page].bytes_used / N_WORD_BYTES;
2366 /* Shouldn't be a free page. */
2367 gc_assert(page_allocated_p(page));
2368 gc_assert(page_table[page].bytes_used != 0);
2370 /* Skip if it's already write-protected, pinned, or unboxed */
2371 if (page_table[page].write_protected
2372 /* FIXME: What's the reason for not write-protecting pinned pages? */
2373 || page_table[page].dont_move
2374 || page_unboxed_p(page))
2377 /* Scan the page for pointers to younger generations or the
2378 * top temp. generation. */
2380 for (j = 0; j < num_words; j++) {
2381 void *ptr = *(page_addr+j);
2382 page_index_t index = find_page_index(ptr);
2384 /* Check that it's in the dynamic space */
2386 if (/* Does it point to a younger or the temp. generation? */
2387 (page_allocated_p(index)
2388 && (page_table[index].bytes_used != 0)
2389 && ((page_table[index].gen < gen)
2390 || (page_table[index].gen == SCRATCH_GENERATION)))
2392 /* Or does it point within a current gc_alloc() region? */
2393 || ((boxed_region.start_addr <= ptr)
2394 && (ptr <= boxed_region.free_pointer))
2395 || ((unboxed_region.start_addr <= ptr)
2396 && (ptr <= unboxed_region.free_pointer))) {
2403 /* Write-protect the page. */
2404 /*FSHOW((stderr, "/write-protecting page %d gen %d\n", page, gen));*/
2406 os_protect((void *)page_addr,
2408 OS_VM_PROT_READ|OS_VM_PROT_EXECUTE);
2410 /* Note the page as protected in the page tables. */
2411 page_table[page].write_protected = 1;
2417 /* Scavenge all generations from FROM to TO, inclusive, except for
2418 * new_space which needs special handling, as new objects may be
2419 * added which are not checked here - use scavenge_newspace generation.
2421 * Write-protected pages should not have any pointers to the
2422 * from_space so do need scavenging; thus write-protected pages are
2423 * not always scavenged. There is some code to check that these pages
2424 * are not written; but to check fully the write-protected pages need
2425 * to be scavenged by disabling the code to skip them.
2427 * Under the current scheme when a generation is GCed the younger
2428 * generations will be empty. So, when a generation is being GCed it
2429 * is only necessary to scavenge the older generations for pointers
2430 * not the younger. So a page that does not have pointers to younger
2431 * generations does not need to be scavenged.
2433 * The write-protection can be used to note pages that don't have
2434 * pointers to younger pages. But pages can be written without having
2435 * pointers to younger generations. After the pages are scavenged here
2436 * they can be scanned for pointers to younger generations and if
2437 * there are none the page can be write-protected.
2439 * One complication is when the newspace is the top temp. generation.
2441 * Enabling SC_GEN_CK scavenges the write-protected pages and checks
2442 * that none were written, which they shouldn't be as they should have
2443 * no pointers to younger generations. This breaks down for weak
2444 * pointers as the objects contain a link to the next and are written
2445 * if a weak pointer is scavenged. Still it's a useful check. */
2447 scavenge_generations(generation_index_t from, generation_index_t to)
2450 page_index_t num_wp = 0;
2454 /* Clear the write_protected_cleared flags on all pages. */
2455 for (i = 0; i < page_table_pages; i++)
2456 page_table[i].write_protected_cleared = 0;
2459 for (i = 0; i < last_free_page; i++) {
2460 generation_index_t generation = page_table[i].gen;
2462 && (page_table[i].bytes_used != 0)
2463 && (generation != new_space)
2464 && (generation >= from)
2465 && (generation <= to)) {
2466 page_index_t last_page,j;
2467 int write_protected=1;
2469 /* This should be the start of a region */
2470 gc_assert(page_table[i].region_start_offset == 0);
2472 /* Now work forward until the end of the region */
2473 for (last_page = i; ; last_page++) {
2475 write_protected && page_table[last_page].write_protected;
2476 if ((page_table[last_page].bytes_used < GENCGC_CARD_BYTES)
2477 /* Or it is CARD_BYTES and is the last in the block */
2478 || (!page_boxed_p(last_page+1))
2479 || (page_table[last_page+1].bytes_used == 0)
2480 || (page_table[last_page+1].gen != generation)
2481 || (page_table[last_page+1].region_start_offset == 0))
2484 if (!write_protected) {
2485 scavenge(page_address(i),
2486 ((unsigned long)(page_table[last_page].bytes_used
2487 + npage_bytes(last_page-i)))
2490 /* Now scan the pages and write protect those that
2491 * don't have pointers to younger generations. */
2492 if (enable_page_protection) {
2493 for (j = i; j <= last_page; j++) {
2494 num_wp += update_page_write_prot(j);
2497 if ((gencgc_verbose > 1) && (num_wp != 0)) {
2499 "/write protected %d pages within generation %d\n",
2500 num_wp, generation));
2508 /* Check that none of the write_protected pages in this generation
2509 * have been written to. */
2510 for (i = 0; i < page_table_pages; i++) {
2511 if (page_allocated_p(i)
2512 && (page_table[i].bytes_used != 0)
2513 && (page_table[i].gen == generation)
2514 && (page_table[i].write_protected_cleared != 0)) {
2515 FSHOW((stderr, "/scavenge_generation() %d\n", generation));
2517 "/page bytes_used=%d region_start_offset=%lu dont_move=%d\n",
2518 page_table[i].bytes_used,
2519 page_table[i].region_start_offset,
2520 page_table[i].dont_move));
2521 lose("write to protected page %d in scavenge_generation()\n", i);
2528 /* Scavenge a newspace generation. As it is scavenged new objects may
2529 * be allocated to it; these will also need to be scavenged. This
2530 * repeats until there are no more objects unscavenged in the
2531 * newspace generation.
2533 * To help improve the efficiency, areas written are recorded by
2534 * gc_alloc() and only these scavenged. Sometimes a little more will be
2535 * scavenged, but this causes no harm. An easy check is done that the
2536 * scavenged bytes equals the number allocated in the previous
2539 * Write-protected pages are not scanned except if they are marked
2540 * dont_move in which case they may have been promoted and still have
2541 * pointers to the from space.
2543 * Write-protected pages could potentially be written by alloc however
2544 * to avoid having to handle re-scavenging of write-protected pages
2545 * gc_alloc() does not write to write-protected pages.
2547 * New areas of objects allocated are recorded alternatively in the two
2548 * new_areas arrays below. */
2549 static struct new_area new_areas_1[NUM_NEW_AREAS];
2550 static struct new_area new_areas_2[NUM_NEW_AREAS];
2552 /* Do one full scan of the new space generation. This is not enough to
2553 * complete the job as new objects may be added to the generation in
2554 * the process which are not scavenged. */
2556 scavenge_newspace_generation_one_scan(generation_index_t generation)
2561 "/starting one full scan of newspace generation %d\n",
2563 for (i = 0; i < last_free_page; i++) {
2564 /* Note that this skips over open regions when it encounters them. */
2566 && (page_table[i].bytes_used != 0)
2567 && (page_table[i].gen == generation)
2568 && ((page_table[i].write_protected == 0)
2569 /* (This may be redundant as write_protected is now
2570 * cleared before promotion.) */
2571 || (page_table[i].dont_move == 1))) {
2572 page_index_t last_page;
2575 /* The scavenge will start at the region_start_offset of
2578 * We need to find the full extent of this contiguous
2579 * block in case objects span pages.
2581 * Now work forward until the end of this contiguous area
2582 * is found. A small area is preferred as there is a
2583 * better chance of its pages being write-protected. */
2584 for (last_page = i; ;last_page++) {
2585 /* If all pages are write-protected and movable,
2586 * then no need to scavenge */
2587 all_wp=all_wp && page_table[last_page].write_protected &&
2588 !page_table[last_page].dont_move;
2590 /* Check whether this is the last page in this
2591 * contiguous block */
2592 if ((page_table[last_page].bytes_used < GENCGC_CARD_BYTES)
2593 /* Or it is CARD_BYTES and is the last in the block */
2594 || (!page_boxed_p(last_page+1))
2595 || (page_table[last_page+1].bytes_used == 0)
2596 || (page_table[last_page+1].gen != generation)
2597 || (page_table[last_page+1].region_start_offset == 0))
2601 /* Do a limited check for write-protected pages. */
2603 long nwords = (((unsigned long)
2604 (page_table[last_page].bytes_used
2605 + npage_bytes(last_page-i)
2606 + page_table[i].region_start_offset))
2608 new_areas_ignore_page = last_page;
2610 scavenge(page_region_start(i), nwords);
2617 "/done with one full scan of newspace generation %d\n",
2621 /* Do a complete scavenge of the newspace generation. */
2623 scavenge_newspace_generation(generation_index_t generation)
2627 /* the new_areas array currently being written to by gc_alloc() */
2628 struct new_area (*current_new_areas)[] = &new_areas_1;
2629 size_t current_new_areas_index;
2631 /* the new_areas created by the previous scavenge cycle */
2632 struct new_area (*previous_new_areas)[] = NULL;
2633 size_t previous_new_areas_index;
2635 /* Flush the current regions updating the tables. */
2636 gc_alloc_update_all_page_tables();
2638 /* Turn on the recording of new areas by gc_alloc(). */
2639 new_areas = current_new_areas;
2640 new_areas_index = 0;
2642 /* Don't need to record new areas that get scavenged anyway during
2643 * scavenge_newspace_generation_one_scan. */
2644 record_new_objects = 1;
2646 /* Start with a full scavenge. */
2647 scavenge_newspace_generation_one_scan(generation);
2649 /* Record all new areas now. */
2650 record_new_objects = 2;
2652 /* Give a chance to weak hash tables to make other objects live.
2653 * FIXME: The algorithm implemented here for weak hash table gcing
2654 * is O(W^2+N) as Bruno Haible warns in
2655 * http://www.haible.de/bruno/papers/cs/weak/WeakDatastructures-writeup.html
2656 * see "Implementation 2". */
2657 scav_weak_hash_tables();
2659 /* Flush the current regions updating the tables. */
2660 gc_alloc_update_all_page_tables();
2662 /* Grab new_areas_index. */
2663 current_new_areas_index = new_areas_index;
2666 "The first scan is finished; current_new_areas_index=%d.\n",
2667 current_new_areas_index));*/
2669 while (current_new_areas_index > 0) {
2670 /* Move the current to the previous new areas */
2671 previous_new_areas = current_new_areas;
2672 previous_new_areas_index = current_new_areas_index;
2674 /* Scavenge all the areas in previous new areas. Any new areas
2675 * allocated are saved in current_new_areas. */
2677 /* Allocate an array for current_new_areas; alternating between
2678 * new_areas_1 and 2 */
2679 if (previous_new_areas == &new_areas_1)
2680 current_new_areas = &new_areas_2;
2682 current_new_areas = &new_areas_1;
2684 /* Set up for gc_alloc(). */
2685 new_areas = current_new_areas;
2686 new_areas_index = 0;
2688 /* Check whether previous_new_areas had overflowed. */
2689 if (previous_new_areas_index >= NUM_NEW_AREAS) {
2691 /* New areas of objects allocated have been lost so need to do a
2692 * full scan to be sure! If this becomes a problem try
2693 * increasing NUM_NEW_AREAS. */
2694 if (gencgc_verbose) {
2695 SHOW("new_areas overflow, doing full scavenge");
2698 /* Don't need to record new areas that get scavenged
2699 * anyway during scavenge_newspace_generation_one_scan. */
2700 record_new_objects = 1;
2702 scavenge_newspace_generation_one_scan(generation);
2704 /* Record all new areas now. */
2705 record_new_objects = 2;
2707 scav_weak_hash_tables();
2709 /* Flush the current regions updating the tables. */
2710 gc_alloc_update_all_page_tables();
2714 /* Work through previous_new_areas. */
2715 for (i = 0; i < previous_new_areas_index; i++) {
2716 page_index_t page = (*previous_new_areas)[i].page;
2717 size_t offset = (*previous_new_areas)[i].offset;
2718 size_t size = (*previous_new_areas)[i].size / N_WORD_BYTES;
2719 gc_assert((*previous_new_areas)[i].size % N_WORD_BYTES == 0);
2720 scavenge(page_address(page)+offset, size);
2723 scav_weak_hash_tables();
2725 /* Flush the current regions updating the tables. */
2726 gc_alloc_update_all_page_tables();
2729 current_new_areas_index = new_areas_index;
2732 "The re-scan has finished; current_new_areas_index=%d.\n",
2733 current_new_areas_index));*/
2736 /* Turn off recording of areas allocated by gc_alloc(). */
2737 record_new_objects = 0;
2742 /* Check that none of the write_protected pages in this generation
2743 * have been written to. */
2744 for (i = 0; i < page_table_pages; i++) {
2745 if (page_allocated_p(i)
2746 && (page_table[i].bytes_used != 0)
2747 && (page_table[i].gen == generation)
2748 && (page_table[i].write_protected_cleared != 0)
2749 && (page_table[i].dont_move == 0)) {
2750 lose("write protected page %d written to in scavenge_newspace_generation\ngeneration=%d dont_move=%d\n",
2751 i, generation, page_table[i].dont_move);
2758 /* Un-write-protect all the pages in from_space. This is done at the
2759 * start of a GC else there may be many page faults while scavenging
2760 * the newspace (I've seen drive the system time to 99%). These pages
2761 * would need to be unprotected anyway before unmapping in
2762 * free_oldspace; not sure what effect this has on paging.. */
2764 unprotect_oldspace(void)
2767 void *region_addr = 0;
2768 void *page_addr = 0;
2769 unsigned long region_bytes = 0;
2771 for (i = 0; i < last_free_page; i++) {
2772 if (page_allocated_p(i)
2773 && (page_table[i].bytes_used != 0)
2774 && (page_table[i].gen == from_space)) {
2776 /* Remove any write-protection. We should be able to rely
2777 * on the write-protect flag to avoid redundant calls. */
2778 if (page_table[i].write_protected) {
2779 page_table[i].write_protected = 0;
2780 page_addr = page_address(i);
2783 region_addr = page_addr;
2784 region_bytes = GENCGC_CARD_BYTES;
2785 } else if (region_addr + region_bytes == page_addr) {
2786 /* Region continue. */
2787 region_bytes += GENCGC_CARD_BYTES;
2789 /* Unprotect previous region. */
2790 os_protect(region_addr, region_bytes, OS_VM_PROT_ALL);
2791 /* First page in new region. */
2792 region_addr = page_addr;
2793 region_bytes = GENCGC_CARD_BYTES;
2799 /* Unprotect last region. */
2800 os_protect(region_addr, region_bytes, OS_VM_PROT_ALL);
2804 /* Work through all the pages and free any in from_space. This
2805 * assumes that all objects have been copied or promoted to an older
2806 * generation. Bytes_allocated and the generation bytes_allocated
2807 * counter are updated. The number of bytes freed is returned. */
2808 static unsigned long
2811 unsigned long bytes_freed = 0;
2812 page_index_t first_page, last_page;
2817 /* Find a first page for the next region of pages. */
2818 while ((first_page < last_free_page)
2819 && (page_free_p(first_page)
2820 || (page_table[first_page].bytes_used == 0)
2821 || (page_table[first_page].gen != from_space)))
2824 if (first_page >= last_free_page)
2827 /* Find the last page of this region. */
2828 last_page = first_page;
2831 /* Free the page. */
2832 bytes_freed += page_table[last_page].bytes_used;
2833 generations[page_table[last_page].gen].bytes_allocated -=
2834 page_table[last_page].bytes_used;
2835 page_table[last_page].allocated = FREE_PAGE_FLAG;
2836 page_table[last_page].bytes_used = 0;
2837 /* Should already be unprotected by unprotect_oldspace(). */
2838 gc_assert(!page_table[last_page].write_protected);
2841 while ((last_page < last_free_page)
2842 && page_allocated_p(last_page)
2843 && (page_table[last_page].bytes_used != 0)
2844 && (page_table[last_page].gen == from_space));
2846 #ifdef READ_PROTECT_FREE_PAGES
2847 os_protect(page_address(first_page),
2848 npage_bytes(last_page-first_page),
2851 first_page = last_page;
2852 } while (first_page < last_free_page);
2854 bytes_allocated -= bytes_freed;
2859 /* Print some information about a pointer at the given address. */
2861 print_ptr(lispobj *addr)
2863 /* If addr is in the dynamic space then out the page information. */
2864 page_index_t pi1 = find_page_index((void*)addr);
2867 fprintf(stderr," %x: page %d alloc %d gen %d bytes_used %d offset %lu dont_move %d\n",
2868 (unsigned long) addr,
2870 page_table[pi1].allocated,
2871 page_table[pi1].gen,
2872 page_table[pi1].bytes_used,
2873 page_table[pi1].region_start_offset,
2874 page_table[pi1].dont_move);
2875 fprintf(stderr," %x %x %x %x (%x) %x %x %x %x\n",
2889 is_in_stack_space(lispobj ptr)
2891 /* For space verification: Pointers can be valid if they point
2892 * to a thread stack space. This would be faster if the thread
2893 * structures had page-table entries as if they were part of
2894 * the heap space. */
2896 for_each_thread(th) {
2897 if ((th->control_stack_start <= (lispobj *)ptr) &&
2898 (th->control_stack_end >= (lispobj *)ptr)) {
2906 verify_space(lispobj *start, size_t words)
2908 int is_in_dynamic_space = (find_page_index((void*)start) != -1);
2909 int is_in_readonly_space =
2910 (READ_ONLY_SPACE_START <= (unsigned long)start &&
2911 (unsigned long)start < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
2915 lispobj thing = *(lispobj*)start;
2917 if (is_lisp_pointer(thing)) {
2918 page_index_t page_index = find_page_index((void*)thing);
2919 long to_readonly_space =
2920 (READ_ONLY_SPACE_START <= thing &&
2921 thing < SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0));
2922 long to_static_space =
2923 (STATIC_SPACE_START <= thing &&
2924 thing < SymbolValue(STATIC_SPACE_FREE_POINTER,0));
2926 /* Does it point to the dynamic space? */
2927 if (page_index != -1) {
2928 /* If it's within the dynamic space it should point to a used
2929 * page. XX Could check the offset too. */
2930 if (page_allocated_p(page_index)
2931 && (page_table[page_index].bytes_used == 0))
2932 lose ("Ptr %p @ %p sees free page.\n", thing, start);
2933 /* Check that it doesn't point to a forwarding pointer! */
2934 if (*((lispobj *)native_pointer(thing)) == 0x01) {
2935 lose("Ptr %p @ %p sees forwarding ptr.\n", thing, start);
2937 /* Check that its not in the RO space as it would then be a
2938 * pointer from the RO to the dynamic space. */
2939 if (is_in_readonly_space) {
2940 lose("ptr to dynamic space %p from RO space %x\n",
2943 /* Does it point to a plausible object? This check slows
2944 * it down a lot (so it's commented out).
2946 * "a lot" is serious: it ate 50 minutes cpu time on
2947 * my duron 950 before I came back from lunch and
2950 * FIXME: Add a variable to enable this
2953 if (!possibly_valid_dynamic_space_pointer((lispobj *)thing)) {
2954 lose("ptr %p to invalid object %p\n", thing, start);
2958 extern void funcallable_instance_tramp;
2959 /* Verify that it points to another valid space. */
2960 if (!to_readonly_space && !to_static_space
2961 && (thing != (lispobj)&funcallable_instance_tramp)
2962 && !is_in_stack_space(thing)) {
2963 lose("Ptr %p @ %p sees junk.\n", thing, start);
2967 if (!(fixnump(thing))) {
2969 switch(widetag_of(*start)) {
2972 case SIMPLE_VECTOR_WIDETAG:
2974 case COMPLEX_WIDETAG:
2975 case SIMPLE_ARRAY_WIDETAG:
2976 case COMPLEX_BASE_STRING_WIDETAG:
2977 #ifdef COMPLEX_CHARACTER_STRING_WIDETAG
2978 case COMPLEX_CHARACTER_STRING_WIDETAG:
2980 case COMPLEX_VECTOR_NIL_WIDETAG:
2981 case COMPLEX_BIT_VECTOR_WIDETAG:
2982 case COMPLEX_VECTOR_WIDETAG:
2983 case COMPLEX_ARRAY_WIDETAG:
2984 case CLOSURE_HEADER_WIDETAG:
2985 case FUNCALLABLE_INSTANCE_HEADER_WIDETAG:
2986 case VALUE_CELL_HEADER_WIDETAG:
2987 case SYMBOL_HEADER_WIDETAG:
2988 case CHARACTER_WIDETAG:
2989 #if N_WORD_BITS == 64
2990 case SINGLE_FLOAT_WIDETAG:
2992 case UNBOUND_MARKER_WIDETAG:
2997 case INSTANCE_HEADER_WIDETAG:
3000 long ntotal = HeaderValue(thing);
3001 lispobj layout = ((struct instance *)start)->slots[0];
3006 nuntagged = ((struct layout *)
3007 native_pointer(layout))->n_untagged_slots;
3008 verify_space(start + 1,
3009 ntotal - fixnum_value(nuntagged));
3013 case CODE_HEADER_WIDETAG:
3015 lispobj object = *start;
3017 long nheader_words, ncode_words, nwords;
3019 struct simple_fun *fheaderp;
3021 code = (struct code *) start;
3023 /* Check that it's not in the dynamic space.
3024 * FIXME: Isn't is supposed to be OK for code
3025 * objects to be in the dynamic space these days? */
3026 if (is_in_dynamic_space
3027 /* It's ok if it's byte compiled code. The trace
3028 * table offset will be a fixnum if it's x86
3029 * compiled code - check.
3031 * FIXME: #^#@@! lack of abstraction here..
3032 * This line can probably go away now that
3033 * there's no byte compiler, but I've got
3034 * too much to worry about right now to try
3035 * to make sure. -- WHN 2001-10-06 */
3036 && fixnump(code->trace_table_offset)
3037 /* Only when enabled */
3038 && verify_dynamic_code_check) {
3040 "/code object at %p in the dynamic space\n",
3044 ncode_words = fixnum_value(code->code_size);
3045 nheader_words = HeaderValue(object);
3046 nwords = ncode_words + nheader_words;
3047 nwords = CEILING(nwords, 2);
3048 /* Scavenge the boxed section of the code data block */
3049 verify_space(start + 1, nheader_words - 1);
3051 /* Scavenge the boxed section of each function
3052 * object in the code data block. */
3053 fheaderl = code->entry_points;
3054 while (fheaderl != NIL) {
3056 (struct simple_fun *) native_pointer(fheaderl);
3057 gc_assert(widetag_of(fheaderp->header) ==
3058 SIMPLE_FUN_HEADER_WIDETAG);
3059 verify_space(&fheaderp->name, 1);
3060 verify_space(&fheaderp->arglist, 1);
3061 verify_space(&fheaderp->type, 1);
3062 fheaderl = fheaderp->next;
3068 /* unboxed objects */
3069 case BIGNUM_WIDETAG:
3070 #if N_WORD_BITS != 64
3071 case SINGLE_FLOAT_WIDETAG:
3073 case DOUBLE_FLOAT_WIDETAG:
3074 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3075 case LONG_FLOAT_WIDETAG:
3077 #ifdef COMPLEX_SINGLE_FLOAT_WIDETAG
3078 case COMPLEX_SINGLE_FLOAT_WIDETAG:
3080 #ifdef COMPLEX_DOUBLE_FLOAT_WIDETAG
3081 case COMPLEX_DOUBLE_FLOAT_WIDETAG:
3083 #ifdef COMPLEX_LONG_FLOAT_WIDETAG
3084 case COMPLEX_LONG_FLOAT_WIDETAG:
3086 case SIMPLE_BASE_STRING_WIDETAG:
3087 #ifdef SIMPLE_CHARACTER_STRING_WIDETAG
3088 case SIMPLE_CHARACTER_STRING_WIDETAG:
3090 case SIMPLE_BIT_VECTOR_WIDETAG:
3091 case SIMPLE_ARRAY_NIL_WIDETAG:
3092 case SIMPLE_ARRAY_UNSIGNED_BYTE_2_WIDETAG:
3093 case SIMPLE_ARRAY_UNSIGNED_BYTE_4_WIDETAG:
3094 case SIMPLE_ARRAY_UNSIGNED_BYTE_7_WIDETAG:
3095 case SIMPLE_ARRAY_UNSIGNED_BYTE_8_WIDETAG:
3096 case SIMPLE_ARRAY_UNSIGNED_BYTE_15_WIDETAG:
3097 case SIMPLE_ARRAY_UNSIGNED_BYTE_16_WIDETAG:
3099 case SIMPLE_ARRAY_UNSIGNED_FIXNUM_WIDETAG:
3101 case SIMPLE_ARRAY_UNSIGNED_BYTE_31_WIDETAG:
3102 case SIMPLE_ARRAY_UNSIGNED_BYTE_32_WIDETAG:
3103 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG
3104 case SIMPLE_ARRAY_UNSIGNED_BYTE_63_WIDETAG:
3106 #ifdef SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG
3107 case SIMPLE_ARRAY_UNSIGNED_BYTE_64_WIDETAG:
3109 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG
3110 case SIMPLE_ARRAY_SIGNED_BYTE_8_WIDETAG:
3112 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG
3113 case SIMPLE_ARRAY_SIGNED_BYTE_16_WIDETAG:
3116 case SIMPLE_ARRAY_FIXNUM_WIDETAG:
3118 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG
3119 case SIMPLE_ARRAY_SIGNED_BYTE_32_WIDETAG:
3121 #ifdef SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG
3122 case SIMPLE_ARRAY_SIGNED_BYTE_64_WIDETAG:
3124 case SIMPLE_ARRAY_SINGLE_FLOAT_WIDETAG:
3125 case SIMPLE_ARRAY_DOUBLE_FLOAT_WIDETAG:
3126 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3127 case SIMPLE_ARRAY_LONG_FLOAT_WIDETAG:
3129 #ifdef SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG
3130 case SIMPLE_ARRAY_COMPLEX_SINGLE_FLOAT_WIDETAG:
3132 #ifdef SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG
3133 case SIMPLE_ARRAY_COMPLEX_DOUBLE_FLOAT_WIDETAG:
3135 #ifdef SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG
3136 case SIMPLE_ARRAY_COMPLEX_LONG_FLOAT_WIDETAG:
3139 case WEAK_POINTER_WIDETAG:
3140 #ifdef NO_TLS_VALUE_MARKER_WIDETAG
3141 case NO_TLS_VALUE_MARKER_WIDETAG:
3143 count = (sizetab[widetag_of(*start)])(start);
3147 lose("Unhandled widetag %p at %p\n",
3148 widetag_of(*start), start);
3160 /* FIXME: It would be nice to make names consistent so that
3161 * foo_size meant size *in* *bytes* instead of size in some
3162 * arbitrary units. (Yes, this caused a bug, how did you guess?:-)
3163 * Some counts of lispobjs are called foo_count; it might be good
3164 * to grep for all foo_size and rename the appropriate ones to
3166 long read_only_space_size =
3167 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0)
3168 - (lispobj*)READ_ONLY_SPACE_START;
3169 long static_space_size =
3170 (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0)
3171 - (lispobj*)STATIC_SPACE_START;
3173 for_each_thread(th) {
3174 long binding_stack_size =
3175 (lispobj*)get_binding_stack_pointer(th)
3176 - (lispobj*)th->binding_stack_start;
3177 verify_space(th->binding_stack_start, binding_stack_size);
3179 verify_space((lispobj*)READ_ONLY_SPACE_START, read_only_space_size);
3180 verify_space((lispobj*)STATIC_SPACE_START , static_space_size);
3184 verify_generation(generation_index_t generation)
3188 for (i = 0; i < last_free_page; i++) {
3189 if (page_allocated_p(i)
3190 && (page_table[i].bytes_used != 0)
3191 && (page_table[i].gen == generation)) {
3192 page_index_t last_page;
3193 int region_allocation = page_table[i].allocated;
3195 /* This should be the start of a contiguous block */
3196 gc_assert(page_table[i].region_start_offset == 0);
3198 /* Need to find the full extent of this contiguous block in case
3199 objects span pages. */
3201 /* Now work forward until the end of this contiguous area is
3203 for (last_page = i; ;last_page++)
3204 /* Check whether this is the last page in this contiguous
3206 if ((page_table[last_page].bytes_used < GENCGC_CARD_BYTES)
3207 /* Or it is CARD_BYTES and is the last in the block */
3208 || (page_table[last_page+1].allocated != region_allocation)
3209 || (page_table[last_page+1].bytes_used == 0)
3210 || (page_table[last_page+1].gen != generation)
3211 || (page_table[last_page+1].region_start_offset == 0))
3214 verify_space(page_address(i),
3216 (page_table[last_page].bytes_used
3217 + npage_bytes(last_page-i)))
3224 /* Check that all the free space is zero filled. */
3226 verify_zero_fill(void)
3230 for (page = 0; page < last_free_page; page++) {
3231 if (page_free_p(page)) {
3232 /* The whole page should be zero filled. */
3233 long *start_addr = (long *)page_address(page);
3236 for (i = 0; i < size; i++) {
3237 if (start_addr[i] != 0) {
3238 lose("free page not zero at %x\n", start_addr + i);
3242 long free_bytes = GENCGC_CARD_BYTES - page_table[page].bytes_used;
3243 if (free_bytes > 0) {
3244 long *start_addr = (long *)((unsigned long)page_address(page)
3245 + page_table[page].bytes_used);
3246 long size = free_bytes / N_WORD_BYTES;
3248 for (i = 0; i < size; i++) {
3249 if (start_addr[i] != 0) {
3250 lose("free region not zero at %x\n", start_addr + i);
3258 /* External entry point for verify_zero_fill */
3260 gencgc_verify_zero_fill(void)
3262 /* Flush the alloc regions updating the tables. */
3263 gc_alloc_update_all_page_tables();
3264 SHOW("verifying zero fill");
3269 verify_dynamic_space(void)
3271 generation_index_t i;
3273 for (i = 0; i <= HIGHEST_NORMAL_GENERATION; i++)
3274 verify_generation(i);
3276 if (gencgc_enable_verify_zero_fill)
3280 /* Write-protect all the dynamic boxed pages in the given generation. */
3282 write_protect_generation_pages(generation_index_t generation)
3286 gc_assert(generation < SCRATCH_GENERATION);
3288 for (start = 0; start < last_free_page; start++) {
3289 if (protect_page_p(start, generation)) {
3293 /* Note the page as protected in the page tables. */
3294 page_table[start].write_protected = 1;
3296 for (last = start + 1; last < last_free_page; last++) {
3297 if (!protect_page_p(last, generation))
3299 page_table[last].write_protected = 1;
3302 page_start = (void *)page_address(start);
3304 os_protect(page_start,
3305 npage_bytes(last - start),
3306 OS_VM_PROT_READ | OS_VM_PROT_EXECUTE);
3312 if (gencgc_verbose > 1) {
3314 "/write protected %d of %d pages in generation %d\n",
3315 count_write_protect_generation_pages(generation),
3316 count_generation_pages(generation),
3321 #if defined(LISP_FEATURE_SB_THREAD) && (defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64))
3323 preserve_context_registers (os_context_t *c)
3326 /* On Darwin the signal context isn't a contiguous block of memory,
3327 * so just preserve_pointering its contents won't be sufficient.
3329 #if defined(LISP_FEATURE_DARWIN)
3330 #if defined LISP_FEATURE_X86
3331 preserve_pointer((void*)*os_context_register_addr(c,reg_EAX));
3332 preserve_pointer((void*)*os_context_register_addr(c,reg_ECX));
3333 preserve_pointer((void*)*os_context_register_addr(c,reg_EDX));
3334 preserve_pointer((void*)*os_context_register_addr(c,reg_EBX));
3335 preserve_pointer((void*)*os_context_register_addr(c,reg_ESI));
3336 preserve_pointer((void*)*os_context_register_addr(c,reg_EDI));
3337 preserve_pointer((void*)*os_context_pc_addr(c));
3338 #elif defined LISP_FEATURE_X86_64
3339 preserve_pointer((void*)*os_context_register_addr(c,reg_RAX));
3340 preserve_pointer((void*)*os_context_register_addr(c,reg_RCX));
3341 preserve_pointer((void*)*os_context_register_addr(c,reg_RDX));
3342 preserve_pointer((void*)*os_context_register_addr(c,reg_RBX));
3343 preserve_pointer((void*)*os_context_register_addr(c,reg_RSI));
3344 preserve_pointer((void*)*os_context_register_addr(c,reg_RDI));
3345 preserve_pointer((void*)*os_context_register_addr(c,reg_R8));
3346 preserve_pointer((void*)*os_context_register_addr(c,reg_R9));
3347 preserve_pointer((void*)*os_context_register_addr(c,reg_R10));
3348 preserve_pointer((void*)*os_context_register_addr(c,reg_R11));
3349 preserve_pointer((void*)*os_context_register_addr(c,reg_R12));
3350 preserve_pointer((void*)*os_context_register_addr(c,reg_R13));
3351 preserve_pointer((void*)*os_context_register_addr(c,reg_R14));
3352 preserve_pointer((void*)*os_context_register_addr(c,reg_R15));
3353 preserve_pointer((void*)*os_context_pc_addr(c));
3355 #error "preserve_context_registers needs to be tweaked for non-x86 Darwin"
3358 for(ptr = ((void **)(c+1))-1; ptr>=(void **)c; ptr--) {
3359 preserve_pointer(*ptr);
3364 /* Garbage collect a generation. If raise is 0 then the remains of the
3365 * generation are not raised to the next generation. */
3367 garbage_collect_generation(generation_index_t generation, int raise)
3369 unsigned long bytes_freed;
3371 unsigned long static_space_size;
3374 gc_assert(generation <= HIGHEST_NORMAL_GENERATION);
3376 /* The oldest generation can't be raised. */
3377 gc_assert((generation != HIGHEST_NORMAL_GENERATION) || (raise == 0));
3379 /* Check if weak hash tables were processed in the previous GC. */
3380 gc_assert(weak_hash_tables == NULL);
3382 /* Initialize the weak pointer list. */
3383 weak_pointers = NULL;
3385 /* When a generation is not being raised it is transported to a
3386 * temporary generation (NUM_GENERATIONS), and lowered when
3387 * done. Set up this new generation. There should be no pages
3388 * allocated to it yet. */
3390 gc_assert(generations[SCRATCH_GENERATION].bytes_allocated == 0);
3393 /* Set the global src and dest. generations */
3394 from_space = generation;
3396 new_space = generation+1;
3398 new_space = SCRATCH_GENERATION;
3400 /* Change to a new space for allocation, resetting the alloc_start_page */
3401 gc_alloc_generation = new_space;
3402 generations[new_space].alloc_start_page = 0;
3403 generations[new_space].alloc_unboxed_start_page = 0;
3404 generations[new_space].alloc_large_start_page = 0;
3405 generations[new_space].alloc_large_unboxed_start_page = 0;
3407 /* Before any pointers are preserved, the dont_move flags on the
3408 * pages need to be cleared. */
3409 for (i = 0; i < last_free_page; i++)
3410 if(page_table[i].gen==from_space)
3411 page_table[i].dont_move = 0;
3413 /* Un-write-protect the old-space pages. This is essential for the
3414 * promoted pages as they may contain pointers into the old-space
3415 * which need to be scavenged. It also helps avoid unnecessary page
3416 * faults as forwarding pointers are written into them. They need to
3417 * be un-protected anyway before unmapping later. */
3418 unprotect_oldspace();
3420 /* Scavenge the stacks' conservative roots. */
3422 /* there are potentially two stacks for each thread: the main
3423 * stack, which may contain Lisp pointers, and the alternate stack.
3424 * We don't ever run Lisp code on the altstack, but it may
3425 * host a sigcontext with lisp objects in it */
3427 /* what we need to do: (1) find the stack pointer for the main
3428 * stack; scavenge it (2) find the interrupt context on the
3429 * alternate stack that might contain lisp values, and scavenge
3432 /* we assume that none of the preceding applies to the thread that
3433 * initiates GC. If you ever call GC from inside an altstack
3434 * handler, you will lose. */
3436 #if defined(LISP_FEATURE_X86) || defined(LISP_FEATURE_X86_64)
3437 /* And if we're saving a core, there's no point in being conservative. */
3438 if (conservative_stack) {
3439 for_each_thread(th) {
3441 void **esp=(void **)-1;
3442 #ifdef LISP_FEATURE_SB_THREAD
3444 if(th==arch_os_get_current_thread()) {
3445 /* Somebody is going to burn in hell for this, but casting
3446 * it in two steps shuts gcc up about strict aliasing. */
3447 esp = (void **)((void *)&raise);
3450 free=fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,th));
3451 for(i=free-1;i>=0;i--) {
3452 os_context_t *c=th->interrupt_contexts[i];
3453 esp1 = (void **) *os_context_register_addr(c,reg_SP);
3454 if (esp1>=(void **)th->control_stack_start &&
3455 esp1<(void **)th->control_stack_end) {
3456 if(esp1<esp) esp=esp1;
3457 preserve_context_registers(c);
3462 esp = (void **)((void *)&raise);
3464 for (ptr = ((void **)th->control_stack_end)-1; ptr >= esp; ptr--) {
3465 preserve_pointer(*ptr);
3470 /* Non-x86oid systems don't have "conservative roots" as such, but
3471 * the same mechanism is used for objects pinned for use by alien
3473 for_each_thread(th) {
3474 lispobj pin_list = SymbolTlValue(PINNED_OBJECTS,th);
3475 while (pin_list != NIL) {
3476 struct cons *list_entry =
3477 (struct cons *)native_pointer(pin_list);
3478 preserve_pointer(list_entry->car);
3479 pin_list = list_entry->cdr;
3485 if (gencgc_verbose > 1) {
3486 long num_dont_move_pages = count_dont_move_pages();
3488 "/non-movable pages due to conservative pointers = %d (%d bytes)\n",
3489 num_dont_move_pages,
3490 npage_bytes(num_dont_move_pages));
3494 /* Scavenge all the rest of the roots. */
3496 #if !defined(LISP_FEATURE_X86) && !defined(LISP_FEATURE_X86_64)
3498 * If not x86, we need to scavenge the interrupt context(s) and the
3503 for_each_thread(th) {
3504 scavenge_interrupt_contexts(th);
3505 scavenge_control_stack(th);
3508 /* Scrub the unscavenged control stack space, so that we can't run
3509 * into any stale pointers in a later GC (this is done by the
3510 * stop-for-gc handler in the other threads). */
3511 scrub_control_stack();
3515 /* Scavenge the Lisp functions of the interrupt handlers, taking
3516 * care to avoid SIG_DFL and SIG_IGN. */
3517 for (i = 0; i < NSIG; i++) {
3518 union interrupt_handler handler = interrupt_handlers[i];
3519 if (!ARE_SAME_HANDLER(handler.c, SIG_IGN) &&
3520 !ARE_SAME_HANDLER(handler.c, SIG_DFL)) {
3521 scavenge((lispobj *)(interrupt_handlers + i), 1);
3524 /* Scavenge the binding stacks. */
3527 for_each_thread(th) {
3528 long len= (lispobj *)get_binding_stack_pointer(th) -
3529 th->binding_stack_start;
3530 scavenge((lispobj *) th->binding_stack_start,len);
3531 #ifdef LISP_FEATURE_SB_THREAD
3532 /* do the tls as well */
3533 len=(SymbolValue(FREE_TLS_INDEX,0) >> WORD_SHIFT) -
3534 (sizeof (struct thread))/(sizeof (lispobj));
3535 scavenge((lispobj *) (th+1),len);
3540 /* The original CMU CL code had scavenge-read-only-space code
3541 * controlled by the Lisp-level variable
3542 * *SCAVENGE-READ-ONLY-SPACE*. It was disabled by default, and it
3543 * wasn't documented under what circumstances it was useful or
3544 * safe to turn it on, so it's been turned off in SBCL. If you
3545 * want/need this functionality, and can test and document it,
3546 * please submit a patch. */
3548 if (SymbolValue(SCAVENGE_READ_ONLY_SPACE) != NIL) {
3549 unsigned long read_only_space_size =
3550 (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER) -
3551 (lispobj*)READ_ONLY_SPACE_START;
3553 "/scavenge read only space: %d bytes\n",
3554 read_only_space_size * sizeof(lispobj)));
3555 scavenge( (lispobj *) READ_ONLY_SPACE_START, read_only_space_size);
3559 /* Scavenge static space. */
3561 (lispobj *)SymbolValue(STATIC_SPACE_FREE_POINTER,0) -
3562 (lispobj *)STATIC_SPACE_START;
3563 if (gencgc_verbose > 1) {
3565 "/scavenge static space: %d bytes\n",
3566 static_space_size * sizeof(lispobj)));
3568 scavenge( (lispobj *) STATIC_SPACE_START, static_space_size);
3570 /* All generations but the generation being GCed need to be
3571 * scavenged. The new_space generation needs special handling as
3572 * objects may be moved in - it is handled separately below. */
3573 scavenge_generations(generation+1, PSEUDO_STATIC_GENERATION);
3575 /* Finally scavenge the new_space generation. Keep going until no
3576 * more objects are moved into the new generation */
3577 scavenge_newspace_generation(new_space);
3579 /* FIXME: I tried reenabling this check when debugging unrelated
3580 * GC weirdness ca. sbcl-0.6.12.45, and it failed immediately.
3581 * Since the current GC code seems to work well, I'm guessing that
3582 * this debugging code is just stale, but I haven't tried to
3583 * figure it out. It should be figured out and then either made to
3584 * work or just deleted. */
3585 #define RESCAN_CHECK 0
3587 /* As a check re-scavenge the newspace once; no new objects should
3590 os_vm_size_t old_bytes_allocated = bytes_allocated;
3591 os_vm_size_t bytes_allocated;
3593 /* Start with a full scavenge. */
3594 scavenge_newspace_generation_one_scan(new_space);
3596 /* Flush the current regions, updating the tables. */
3597 gc_alloc_update_all_page_tables();
3599 bytes_allocated = bytes_allocated - old_bytes_allocated;
3601 if (bytes_allocated != 0) {
3602 lose("Rescan of new_space allocated %d more bytes.\n",
3608 scan_weak_hash_tables();
3609 scan_weak_pointers();
3611 /* Flush the current regions, updating the tables. */
3612 gc_alloc_update_all_page_tables();
3614 /* Free the pages in oldspace, but not those marked dont_move. */
3615 bytes_freed = free_oldspace();
3617 /* If the GC is not raising the age then lower the generation back
3618 * to its normal generation number */
3620 for (i = 0; i < last_free_page; i++)
3621 if ((page_table[i].bytes_used != 0)
3622 && (page_table[i].gen == SCRATCH_GENERATION))
3623 page_table[i].gen = generation;
3624 gc_assert(generations[generation].bytes_allocated == 0);
3625 generations[generation].bytes_allocated =
3626 generations[SCRATCH_GENERATION].bytes_allocated;
3627 generations[SCRATCH_GENERATION].bytes_allocated = 0;
3630 /* Reset the alloc_start_page for generation. */
3631 generations[generation].alloc_start_page = 0;
3632 generations[generation].alloc_unboxed_start_page = 0;
3633 generations[generation].alloc_large_start_page = 0;
3634 generations[generation].alloc_large_unboxed_start_page = 0;
3636 if (generation >= verify_gens) {
3637 if (gencgc_verbose) {
3641 verify_dynamic_space();
3644 /* Set the new gc trigger for the GCed generation. */
3645 generations[generation].gc_trigger =
3646 generations[generation].bytes_allocated
3647 + generations[generation].bytes_consed_between_gc;
3650 generations[generation].num_gc = 0;
3652 ++generations[generation].num_gc;
3656 /* Update last_free_page, then SymbolValue(ALLOCATION_POINTER). */
3658 update_dynamic_space_free_pointer(void)
3660 page_index_t last_page = -1, i;
3662 for (i = 0; i < last_free_page; i++)
3663 if (page_allocated_p(i) && (page_table[i].bytes_used != 0))
3666 last_free_page = last_page+1;
3668 set_alloc_pointer((lispobj)(page_address(last_free_page)));
3669 return 0; /* dummy value: return something ... */
3673 remap_page_range (page_index_t from, page_index_t to)
3675 /* There's a mysterious Solaris/x86 problem with using mmap
3676 * tricks for memory zeroing. See sbcl-devel thread
3677 * "Re: patch: standalone executable redux".
3679 #if defined(LISP_FEATURE_SUNOS)
3680 zero_and_mark_pages(from, to);
3683 release_granularity = gencgc_release_granularity/GENCGC_CARD_BYTES,
3684 release_mask = release_granularity-1,
3686 aligned_from = (from+release_mask)&~release_mask,
3687 aligned_end = (end&~release_mask);
3689 if (aligned_from < aligned_end) {
3690 zero_pages_with_mmap(aligned_from, aligned_end-1);
3691 if (aligned_from != from)
3692 zero_and_mark_pages(from, aligned_from-1);
3693 if (aligned_end != end)
3694 zero_and_mark_pages(aligned_end, end-1);
3696 zero_and_mark_pages(from, to);
3702 remap_free_pages (page_index_t from, page_index_t to, int forcibly)
3704 page_index_t first_page, last_page;
3707 return remap_page_range(from, to);
3709 for (first_page = from; first_page <= to; first_page++) {
3710 if (page_allocated_p(first_page) ||
3711 (page_table[first_page].need_to_zero == 0))
3714 last_page = first_page + 1;
3715 while (page_free_p(last_page) &&
3716 (last_page <= to) &&
3717 (page_table[last_page].need_to_zero == 1))
3720 remap_page_range(first_page, last_page-1);
3722 first_page = last_page;
3726 generation_index_t small_generation_limit = 1;
3728 /* GC all generations newer than last_gen, raising the objects in each
3729 * to the next older generation - we finish when all generations below
3730 * last_gen are empty. Then if last_gen is due for a GC, or if
3731 * last_gen==NUM_GENERATIONS (the scratch generation? eh?) we GC that
3732 * too. The valid range for last_gen is: 0,1,...,NUM_GENERATIONS.
3734 * We stop collecting at gencgc_oldest_gen_to_gc, even if this is less than
3735 * last_gen (oh, and note that by default it is NUM_GENERATIONS-1) */
3737 collect_garbage(generation_index_t last_gen)
3739 generation_index_t gen = 0, i;
3740 int raise, more = 0;
3742 /* The largest value of last_free_page seen since the time
3743 * remap_free_pages was called. */
3744 static page_index_t high_water_mark = 0;
3746 FSHOW((stderr, "/entering collect_garbage(%d)\n", last_gen));
3747 log_generation_stats(gc_logfile, "=== GC Start ===");
3751 if (last_gen > HIGHEST_NORMAL_GENERATION+1) {
3753 "/collect_garbage: last_gen = %d, doing a level 0 GC\n",
3758 /* Flush the alloc regions updating the tables. */
3759 gc_alloc_update_all_page_tables();
3761 /* Verify the new objects created by Lisp code. */
3762 if (pre_verify_gen_0) {
3763 FSHOW((stderr, "pre-checking generation 0\n"));
3764 verify_generation(0);
3767 if (gencgc_verbose > 1)
3768 print_generation_stats();
3771 /* Collect the generation. */
3773 if (more || (gen >= gencgc_oldest_gen_to_gc)) {
3774 /* Never raise the oldest generation. Never raise the extra generation
3775 * collected due to more-flag. */
3781 || (generations[gen].num_gc >= generations[gen].number_of_gcs_before_promotion);
3782 /* If we would not normally raise this one, but we're
3783 * running low on space in comparison to the object-sizes
3784 * we've been seeing, raise it and collect the next one
3786 if (!raise && gen == last_gen) {
3787 more = (2*large_allocation) >= (dynamic_space_size - bytes_allocated);
3792 if (gencgc_verbose > 1) {
3794 "starting GC of generation %d with raise=%d alloc=%d trig=%d GCs=%d\n",
3797 generations[gen].bytes_allocated,
3798 generations[gen].gc_trigger,
3799 generations[gen].num_gc));
3802 /* If an older generation is being filled, then update its
3805 generations[gen+1].cum_sum_bytes_allocated +=
3806 generations[gen+1].bytes_allocated;
3809 garbage_collect_generation(gen, raise);
3811 /* Reset the memory age cum_sum. */
3812 generations[gen].cum_sum_bytes_allocated = 0;
3814 if (gencgc_verbose > 1) {
3815 FSHOW((stderr, "GC of generation %d finished:\n", gen));
3816 print_generation_stats();
3820 } while ((gen <= gencgc_oldest_gen_to_gc)
3821 && ((gen < last_gen)
3824 && (generations[gen].bytes_allocated
3825 > generations[gen].gc_trigger)
3826 && (generation_average_age(gen)
3827 > generations[gen].minimum_age_before_gc))));
3829 /* Now if gen-1 was raised all generations before gen are empty.
3830 * If it wasn't raised then all generations before gen-1 are empty.
3832 * Now objects within this gen's pages cannot point to younger
3833 * generations unless they are written to. This can be exploited
3834 * by write-protecting the pages of gen; then when younger
3835 * generations are GCed only the pages which have been written
3840 gen_to_wp = gen - 1;
3842 /* There's not much point in WPing pages in generation 0 as it is
3843 * never scavenged (except promoted pages). */
3844 if ((gen_to_wp > 0) && enable_page_protection) {
3845 /* Check that they are all empty. */
3846 for (i = 0; i < gen_to_wp; i++) {
3847 if (generations[i].bytes_allocated)
3848 lose("trying to write-protect gen. %d when gen. %d nonempty\n",
3851 write_protect_generation_pages(gen_to_wp);
3854 /* Set gc_alloc() back to generation 0. The current regions should
3855 * be flushed after the above GCs. */
3856 gc_assert((boxed_region.free_pointer - boxed_region.start_addr) == 0);
3857 gc_alloc_generation = 0;
3859 /* Save the high-water mark before updating last_free_page */
3860 if (last_free_page > high_water_mark)
3861 high_water_mark = last_free_page;
3863 update_dynamic_space_free_pointer();
3865 /* Update auto_gc_trigger. Make sure we trigger the next GC before
3866 * running out of heap! */
3867 if (bytes_consed_between_gcs >= dynamic_space_size - bytes_allocated)
3868 auto_gc_trigger = bytes_allocated + bytes_consed_between_gcs;
3870 auto_gc_trigger = bytes_allocated + (dynamic_space_size - bytes_allocated)/2;
3873 fprintf(stderr,"Next gc when %"OS_VM_SIZE_FMT" bytes have been consed\n",
3876 /* If we did a big GC (arbitrarily defined as gen > 1), release memory
3879 if (gen > small_generation_limit) {
3880 if (last_free_page > high_water_mark)
3881 high_water_mark = last_free_page;
3882 remap_free_pages(0, high_water_mark, 0);
3883 high_water_mark = 0;
3887 large_allocation = 0;
3889 log_generation_stats(gc_logfile, "=== GC End ===");
3890 SHOW("returning from collect_garbage");
3893 /* This is called by Lisp PURIFY when it is finished. All live objects
3894 * will have been moved to the RO and Static heaps. The dynamic space
3895 * will need a full re-initialization. We don't bother having Lisp
3896 * PURIFY flush the current gc_alloc() region, as the page_tables are
3897 * re-initialized, and every page is zeroed to be sure. */
3901 page_index_t page, last_page;
3903 if (gencgc_verbose > 1) {
3904 SHOW("entering gc_free_heap");
3907 for (page = 0; page < page_table_pages; page++) {
3908 /* Skip free pages which should already be zero filled. */
3909 if (page_allocated_p(page)) {
3911 for (last_page = page;
3912 (last_page < page_table_pages) && page_allocated_p(last_page);
3914 /* Mark the page free. The other slots are assumed invalid
3915 * when it is a FREE_PAGE_FLAG and bytes_used is 0 and it
3916 * should not be write-protected -- except that the
3917 * generation is used for the current region but it sets
3919 page_table[page].allocated = FREE_PAGE_FLAG;
3920 page_table[page].bytes_used = 0;
3921 page_table[page].write_protected = 0;
3924 #ifndef LISP_FEATURE_WIN32 /* Pages already zeroed on win32? Not sure
3925 * about this change. */
3926 page_start = (void *)page_address(page);
3927 os_protect(page_start, npage_bytes(last_page-page), OS_VM_PROT_ALL);
3928 remap_free_pages(page, last_page-1, 1);
3931 } else if (gencgc_zero_check_during_free_heap) {
3932 /* Double-check that the page is zero filled. */
3935 gc_assert(page_free_p(page));
3936 gc_assert(page_table[page].bytes_used == 0);
3937 page_start = (long *)page_address(page);
3938 for (i=0; i<GENCGC_CARD_BYTES/sizeof(long); i++) {
3939 if (page_start[i] != 0) {
3940 lose("free region not zero at %x\n", page_start + i);
3946 bytes_allocated = 0;
3948 /* Initialize the generations. */
3949 for (page = 0; page < NUM_GENERATIONS; page++) {
3950 generations[page].alloc_start_page = 0;
3951 generations[page].alloc_unboxed_start_page = 0;
3952 generations[page].alloc_large_start_page = 0;
3953 generations[page].alloc_large_unboxed_start_page = 0;
3954 generations[page].bytes_allocated = 0;
3955 generations[page].gc_trigger = 2000000;
3956 generations[page].num_gc = 0;
3957 generations[page].cum_sum_bytes_allocated = 0;
3960 if (gencgc_verbose > 1)
3961 print_generation_stats();
3963 /* Initialize gc_alloc(). */
3964 gc_alloc_generation = 0;
3966 gc_set_region_empty(&boxed_region);
3967 gc_set_region_empty(&unboxed_region);
3970 set_alloc_pointer((lispobj)((char *)heap_base));
3972 if (verify_after_free_heap) {
3973 /* Check whether purify has left any bad pointers. */
3974 FSHOW((stderr, "checking after free_heap\n"));
3984 /* Compute the number of pages needed for the dynamic space.
3985 * Dynamic space size should be aligned on page size. */
3986 page_table_pages = dynamic_space_size/GENCGC_CARD_BYTES;
3987 gc_assert(dynamic_space_size == npage_bytes(page_table_pages));
3989 /* Default nursery size to 5% of the total dynamic space size,
3991 bytes_consed_between_gcs = dynamic_space_size/(os_vm_size_t)20;
3992 if (bytes_consed_between_gcs < (1024*1024))
3993 bytes_consed_between_gcs = 1024*1024;
3995 /* The page_table must be allocated using "calloc" to initialize
3996 * the page structures correctly. There used to be a separate
3997 * initialization loop (now commented out; see below) but that was
3998 * unnecessary and did hurt startup time. */
3999 page_table = calloc(page_table_pages, sizeof(struct page));
4000 gc_assert(page_table);
4003 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
4004 transother[SIMPLE_ARRAY_WIDETAG] = trans_boxed_large;
4006 heap_base = (void*)DYNAMIC_SPACE_START;
4008 /* The page structures are initialized implicitly when page_table
4009 * is allocated with "calloc" above. Formerly we had the following
4010 * explicit initialization here (comments converted to C99 style
4011 * for readability as C's block comments don't nest):
4013 * // Initialize each page structure.
4014 * for (i = 0; i < page_table_pages; i++) {
4015 * // Initialize all pages as free.
4016 * page_table[i].allocated = FREE_PAGE_FLAG;
4017 * page_table[i].bytes_used = 0;
4019 * // Pages are not write-protected at startup.
4020 * page_table[i].write_protected = 0;
4023 * Without this loop the image starts up much faster when dynamic
4024 * space is large -- which it is on 64-bit platforms already by
4025 * default -- and when "calloc" for large arrays is implemented
4026 * using copy-on-write of a page of zeroes -- which it is at least
4027 * on Linux. In this case the pages that page_table_pages is stored
4028 * in are mapped and cleared not before the corresponding part of
4029 * dynamic space is used. For example, this saves clearing 16 MB of
4030 * memory at startup if the page size is 4 KB and the size of
4031 * dynamic space is 4 GB.
4032 * FREE_PAGE_FLAG must be 0 for this to work correctly which is
4033 * asserted below: */
4035 /* Compile time assertion: If triggered, declares an array
4036 * of dimension -1 forcing a syntax error. The intent of the
4037 * assignment is to avoid an "unused variable" warning. */
4038 char assert_free_page_flag_0[(FREE_PAGE_FLAG) ? -1 : 1];
4039 assert_free_page_flag_0[0] = assert_free_page_flag_0[0];
4042 bytes_allocated = 0;
4044 /* Initialize the generations.
4046 * FIXME: very similar to code in gc_free_heap(), should be shared */
4047 for (i = 0; i < NUM_GENERATIONS; i++) {
4048 generations[i].alloc_start_page = 0;
4049 generations[i].alloc_unboxed_start_page = 0;
4050 generations[i].alloc_large_start_page = 0;
4051 generations[i].alloc_large_unboxed_start_page = 0;
4052 generations[i].bytes_allocated = 0;
4053 generations[i].gc_trigger = 2000000;
4054 generations[i].num_gc = 0;
4055 generations[i].cum_sum_bytes_allocated = 0;
4056 /* the tune-able parameters */
4057 generations[i].bytes_consed_between_gc = bytes_consed_between_gcs;
4058 generations[i].number_of_gcs_before_promotion = 1;
4059 generations[i].minimum_age_before_gc = 0.75;
4062 /* Initialize gc_alloc. */
4063 gc_alloc_generation = 0;
4064 gc_set_region_empty(&boxed_region);
4065 gc_set_region_empty(&unboxed_region);
4070 /* Pick up the dynamic space from after a core load.
4072 * The ALLOCATION_POINTER points to the end of the dynamic space.
4076 gencgc_pickup_dynamic(void)
4078 page_index_t page = 0;
4079 void *alloc_ptr = (void *)get_alloc_pointer();
4080 lispobj *prev=(lispobj *)page_address(page);
4081 generation_index_t gen = PSEUDO_STATIC_GENERATION;
4083 lispobj *first,*ptr= (lispobj *)page_address(page);
4085 if (!gencgc_partial_pickup || page_allocated_p(page)) {
4086 /* It is possible, though rare, for the saved page table
4087 * to contain free pages below alloc_ptr. */
4088 page_table[page].gen = gen;
4089 page_table[page].bytes_used = GENCGC_CARD_BYTES;
4090 page_table[page].large_object = 0;
4091 page_table[page].write_protected = 0;
4092 page_table[page].write_protected_cleared = 0;
4093 page_table[page].dont_move = 0;
4094 page_table[page].need_to_zero = 1;
4097 if (!gencgc_partial_pickup) {
4098 page_table[page].allocated = BOXED_PAGE_FLAG;
4099 first=gc_search_space(prev,(ptr+2)-prev,ptr);
4102 page_table[page].region_start_offset =
4103 page_address(page) - (void *)prev;
4106 } while (page_address(page) < alloc_ptr);
4108 last_free_page = page;
4110 generations[gen].bytes_allocated = npage_bytes(page);
4111 bytes_allocated = npage_bytes(page);
4113 gc_alloc_update_all_page_tables();
4114 write_protect_generation_pages(gen);
4118 gc_initialize_pointers(void)
4120 gencgc_pickup_dynamic();
4124 /* alloc(..) is the external interface for memory allocation. It
4125 * allocates to generation 0. It is not called from within the garbage
4126 * collector as it is only external uses that need the check for heap
4127 * size (GC trigger) and to disable the interrupts (interrupts are
4128 * always disabled during a GC).
4130 * The vops that call alloc(..) assume that the returned space is zero-filled.
4131 * (E.g. the most significant word of a 2-word bignum in MOVE-FROM-UNSIGNED.)
4133 * The check for a GC trigger is only performed when the current
4134 * region is full, so in most cases it's not needed. */
4136 static inline lispobj *
4137 general_alloc_internal(long nbytes, int page_type_flag, struct alloc_region *region,
4138 struct thread *thread)
4140 #ifndef LISP_FEATURE_WIN32
4141 lispobj alloc_signal;
4144 void *new_free_pointer;
4146 gc_assert(nbytes>0);
4148 /* Check for alignment allocation problems. */
4149 gc_assert((((unsigned long)region->free_pointer & LOWTAG_MASK) == 0)
4150 && ((nbytes & LOWTAG_MASK) == 0));
4152 /* Must be inside a PA section. */
4153 gc_assert(get_pseudo_atomic_atomic(thread));
4155 if (nbytes > large_allocation)
4156 large_allocation = nbytes;
4158 /* maybe we can do this quickly ... */
4159 new_free_pointer = region->free_pointer + nbytes;
4160 if (new_free_pointer <= region->end_addr) {
4161 new_obj = (void*)(region->free_pointer);
4162 region->free_pointer = new_free_pointer;
4163 return(new_obj); /* yup */
4166 /* we have to go the long way around, it seems. Check whether we
4167 * should GC in the near future
4169 if (auto_gc_trigger && bytes_allocated+nbytes > auto_gc_trigger) {
4170 /* Don't flood the system with interrupts if the need to gc is
4171 * already noted. This can happen for example when SUB-GC
4172 * allocates or after a gc triggered in a WITHOUT-GCING. */
4173 if (SymbolValue(GC_PENDING,thread) == NIL) {
4174 /* set things up so that GC happens when we finish the PA
4176 SetSymbolValue(GC_PENDING,T,thread);
4177 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
4178 set_pseudo_atomic_interrupted(thread);
4179 #ifdef LISP_FEATURE_PPC
4180 /* PPC calls alloc() from a trap or from pa_alloc(),
4181 * look up the most context if it's from a trap. */
4183 os_context_t *context =
4184 thread->interrupt_data->allocation_trap_context;
4185 maybe_save_gc_mask_and_block_deferrables
4186 (context ? os_context_sigmask_addr(context) : NULL);
4189 maybe_save_gc_mask_and_block_deferrables(NULL);
4194 new_obj = gc_alloc_with_region(nbytes, page_type_flag, region, 0);
4196 #ifndef LISP_FEATURE_WIN32
4197 alloc_signal = SymbolValue(ALLOC_SIGNAL,thread);
4198 if ((alloc_signal & FIXNUM_TAG_MASK) == 0) {
4199 if ((signed long) alloc_signal <= 0) {
4200 SetSymbolValue(ALLOC_SIGNAL, T, thread);
4203 SetSymbolValue(ALLOC_SIGNAL,
4204 alloc_signal - (1 << N_FIXNUM_TAG_BITS),
4214 general_alloc(long nbytes, int page_type_flag)
4216 struct thread *thread = arch_os_get_current_thread();
4217 /* Select correct region, and call general_alloc_internal with it.
4218 * For other then boxed allocation we must lock first, since the
4219 * region is shared. */
4220 if (BOXED_PAGE_FLAG & page_type_flag) {
4221 #ifdef LISP_FEATURE_SB_THREAD
4222 struct alloc_region *region = (thread ? &(thread->alloc_region) : &boxed_region);
4224 struct alloc_region *region = &boxed_region;
4226 return general_alloc_internal(nbytes, page_type_flag, region, thread);
4227 } else if (UNBOXED_PAGE_FLAG == page_type_flag) {
4229 gc_assert(0 == thread_mutex_lock(&allocation_lock));
4230 obj = general_alloc_internal(nbytes, page_type_flag, &unboxed_region, thread);
4231 gc_assert(0 == thread_mutex_unlock(&allocation_lock));
4234 lose("bad page type flag: %d", page_type_flag);
4241 gc_assert(get_pseudo_atomic_atomic(arch_os_get_current_thread()));
4242 return general_alloc(nbytes, BOXED_PAGE_FLAG);
4246 * shared support for the OS-dependent signal handlers which
4247 * catch GENCGC-related write-protect violations
4249 void unhandled_sigmemoryfault(void* addr);
4251 /* Depending on which OS we're running under, different signals might
4252 * be raised for a violation of write protection in the heap. This
4253 * function factors out the common generational GC magic which needs
4254 * to invoked in this case, and should be called from whatever signal
4255 * handler is appropriate for the OS we're running under.
4257 * Return true if this signal is a normal generational GC thing that
4258 * we were able to handle, or false if it was abnormal and control
4259 * should fall through to the general SIGSEGV/SIGBUS/whatever logic.
4261 * We have two control flags for this: one causes us to ignore faults
4262 * on unprotected pages completely, and the second complains to stderr
4263 * but allows us to continue without losing.
4265 extern boolean ignore_memoryfaults_on_unprotected_pages;
4266 boolean ignore_memoryfaults_on_unprotected_pages = 0;
4268 extern boolean continue_after_memoryfault_on_unprotected_pages;
4269 boolean continue_after_memoryfault_on_unprotected_pages = 0;
4272 gencgc_handle_wp_violation(void* fault_addr)
4274 page_index_t page_index = find_page_index(fault_addr);
4277 FSHOW((stderr, "heap WP violation? fault_addr=%x, page_index=%d\n",
4278 fault_addr, page_index));
4281 /* Check whether the fault is within the dynamic space. */
4282 if (page_index == (-1)) {
4284 /* It can be helpful to be able to put a breakpoint on this
4285 * case to help diagnose low-level problems. */
4286 unhandled_sigmemoryfault(fault_addr);
4288 /* not within the dynamic space -- not our responsibility */
4293 ret = thread_mutex_lock(&free_pages_lock);
4294 gc_assert(ret == 0);
4295 if (page_table[page_index].write_protected) {
4296 /* Unprotect the page. */
4297 os_protect(page_address(page_index), GENCGC_CARD_BYTES, OS_VM_PROT_ALL);
4298 page_table[page_index].write_protected_cleared = 1;
4299 page_table[page_index].write_protected = 0;
4300 } else if (!ignore_memoryfaults_on_unprotected_pages) {
4301 /* The only acceptable reason for this signal on a heap
4302 * access is that GENCGC write-protected the page.
4303 * However, if two CPUs hit a wp page near-simultaneously,
4304 * we had better not have the second one lose here if it
4305 * does this test after the first one has already set wp=0
4307 if(page_table[page_index].write_protected_cleared != 1) {
4308 void lisp_backtrace(int frames);
4311 "Fault @ %p, page %"PAGE_INDEX_FMT" not marked as write-protected:\n"
4312 " boxed_region.first_page: %"PAGE_INDEX_FMT","
4313 " boxed_region.last_page %"PAGE_INDEX_FMT"\n"
4314 " page.region_start_offset: %"OS_VM_SIZE_FMT"\n"
4315 " page.bytes_used: %"PAGE_BYTES_FMT"\n"
4316 " page.allocated: %d\n"
4317 " page.write_protected: %d\n"
4318 " page.write_protected_cleared: %d\n"
4319 " page.generation: %d\n",
4322 boxed_region.first_page,
4323 boxed_region.last_page,
4324 page_table[page_index].region_start_offset,
4325 page_table[page_index].bytes_used,
4326 page_table[page_index].allocated,
4327 page_table[page_index].write_protected,
4328 page_table[page_index].write_protected_cleared,
4329 page_table[page_index].gen);
4330 if (!continue_after_memoryfault_on_unprotected_pages)
4334 ret = thread_mutex_unlock(&free_pages_lock);
4335 gc_assert(ret == 0);
4336 /* Don't worry, we can handle it. */
4340 /* This is to be called when we catch a SIGSEGV/SIGBUS, determine that
4341 * it's not just a case of the program hitting the write barrier, and
4342 * are about to let Lisp deal with it. It's basically just a
4343 * convenient place to set a gdb breakpoint. */
4345 unhandled_sigmemoryfault(void *addr)
4348 void gc_alloc_update_all_page_tables(void)
4350 /* Flush the alloc regions updating the tables. */
4353 gc_alloc_update_page_tables(BOXED_PAGE_FLAG, &th->alloc_region);
4354 gc_alloc_update_page_tables(UNBOXED_PAGE_FLAG, &unboxed_region);
4355 gc_alloc_update_page_tables(BOXED_PAGE_FLAG, &boxed_region);
4359 gc_set_region_empty(struct alloc_region *region)
4361 region->first_page = 0;
4362 region->last_page = -1;
4363 region->start_addr = page_address(0);
4364 region->free_pointer = page_address(0);
4365 region->end_addr = page_address(0);
4369 zero_all_free_pages()
4373 for (i = 0; i < last_free_page; i++) {
4374 if (page_free_p(i)) {
4375 #ifdef READ_PROTECT_FREE_PAGES
4376 os_protect(page_address(i),
4385 /* Things to do before doing a final GC before saving a core (without
4388 * + Pages in large_object pages aren't moved by the GC, so we need to
4389 * unset that flag from all pages.
4390 * + The pseudo-static generation isn't normally collected, but it seems
4391 * reasonable to collect it at least when saving a core. So move the
4392 * pages to a normal generation.
4395 prepare_for_final_gc ()
4398 for (i = 0; i < last_free_page; i++) {
4399 page_table[i].large_object = 0;
4400 if (page_table[i].gen == PSEUDO_STATIC_GENERATION) {
4401 int used = page_table[i].bytes_used;
4402 page_table[i].gen = HIGHEST_NORMAL_GENERATION;
4403 generations[PSEUDO_STATIC_GENERATION].bytes_allocated -= used;
4404 generations[HIGHEST_NORMAL_GENERATION].bytes_allocated += used;
4410 /* Do a non-conservative GC, and then save a core with the initial
4411 * function being set to the value of the static symbol
4412 * SB!VM:RESTART-LISP-FUNCTION */
4414 gc_and_save(char *filename, boolean prepend_runtime,
4415 boolean save_runtime_options,
4416 boolean compressed, int compression_level)
4419 void *runtime_bytes = NULL;
4420 size_t runtime_size;
4422 file = prepare_to_save(filename, prepend_runtime, &runtime_bytes,
4427 conservative_stack = 0;
4429 /* The filename might come from Lisp, and be moved by the now
4430 * non-conservative GC. */
4431 filename = strdup(filename);
4433 /* Collect twice: once into relatively high memory, and then back
4434 * into low memory. This compacts the retained data into the lower
4435 * pages, minimizing the size of the core file.
4437 prepare_for_final_gc();
4438 gencgc_alloc_start_page = last_free_page;
4439 collect_garbage(HIGHEST_NORMAL_GENERATION+1);
4441 prepare_for_final_gc();
4442 gencgc_alloc_start_page = -1;
4443 collect_garbage(HIGHEST_NORMAL_GENERATION+1);
4445 if (prepend_runtime)
4446 save_runtime_to_filehandle(file, runtime_bytes, runtime_size);
4448 /* The dumper doesn't know that pages need to be zeroed before use. */
4449 zero_all_free_pages();
4450 save_to_filehandle(file, filename, SymbolValue(RESTART_LISP_FUNCTION,0),
4451 prepend_runtime, save_runtime_options,
4452 compressed ? compression_level : COMPRESSION_LEVEL_NONE);
4453 /* Oops. Save still managed to fail. Since we've mangled the stack
4454 * beyond hope, there's not much we can do.
4455 * (beyond FUNCALLing RESTART_LISP_FUNCTION, but I suspect that's
4456 * going to be rather unsatisfactory too... */
4457 lose("Attempt to save core after non-conservative GC failed.\n");