2 * stop and copy GC based on Cheney's algorithm
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.
18 #include <sys/resource.h>
24 #include "gc-internal.h"
26 #include "interrupt.h"
30 #include "genesis/static-symbols.h"
31 #include "genesis/primitive-objects.h"
35 /* So you need to debug? */
38 #define DEBUG_SPACE_PREDICATES
39 #define DEBUG_SCAVENGE_VERBOSE
40 #define DEBUG_COPY_VERBOSE
45 lispobj *from_space_free_pointer;
48 lispobj *new_space_free_pointer;
50 static void scavenge_newspace(void);
53 /* collecting garbage */
57 tv_diff(struct timeval *x, struct timeval *y)
59 return (((double) x->tv_sec + (double) x->tv_usec * 1.0e-6) -
60 ((double) y->tv_sec + (double) y->tv_usec * 1.0e-6));
64 #define BYTES_ZERO_BEFORE_END (1<<12)
66 /* FIXME do we need this? Doesn't it duplicate lisp code in
67 * scrub-control-stack? */
72 lispobj *ptr = current_control_stack_pointer;
78 } while (((unsigned long)ptr) & (BYTES_ZERO_BEFORE_END-1));
83 } while (((unsigned long)ptr) & (BYTES_ZERO_BEFORE_END-1));
90 gc_general_alloc(long bytes, int unboxed_p, int quick_p) {
91 lispobj *new=new_space_free_pointer;
92 new_space_free_pointer+=(bytes/N_WORD_BYTES);
96 lispobj copy_large_unboxed_object(lispobj object, long nwords) {
97 return copy_object(object,nwords);
99 lispobj copy_unboxed_object(lispobj object, long nwords) {
100 return copy_object(object,nwords);
102 lispobj copy_large_object(lispobj object, long nwords) {
103 return copy_object(object,nwords);
106 /* Note: The generic GC interface we're implementing passes us a
107 * last_generation argument. That's meaningless for us, since we're
108 * not a generational GC. So we ignore it. */
110 collect_garbage(generation_index_t ignore)
113 struct timeval start_tv, stop_tv;
114 struct rusage start_rusage, stop_rusage;
115 double real_time, system_time, user_time;
116 double percent_retained, gc_rate;
117 unsigned long size_discarded;
119 unsigned long size_retained;
120 lispobj *current_static_space_free_pointer;
121 unsigned long static_space_size;
122 unsigned long control_stack_size, binding_stack_size;
124 struct thread *th=arch_os_get_current_thread();
127 printf("[Collecting garbage ... \n");
129 getrusage(RUSAGE_SELF, &start_rusage);
130 gettimeofday(&start_tv, (struct timezone *) 0);
133 /* it's possible that signals are blocked already if this was called
134 * from a signal handler (e.g. with the sigsegv gc_trigger stuff) */
136 sigaddset_blockable(&tmp);
137 thread_sigmask(SIG_BLOCK, &tmp, &old);
139 current_static_space_free_pointer =
140 (lispobj *) ((unsigned long)
141 SymbolValue(STATIC_SPACE_FREE_POINTER,0));
144 /* Set up from space and new space pointers. */
146 from_space = current_dynamic_space;
147 from_space_free_pointer = dynamic_space_free_pointer;
150 fprintf(stderr,"from_space = %lx\n",
151 (unsigned long) current_dynamic_space);
153 if (current_dynamic_space == (lispobj *) DYNAMIC_0_SPACE_START)
154 new_space = (lispobj *)DYNAMIC_1_SPACE_START;
155 else if (current_dynamic_space == (lispobj *) DYNAMIC_1_SPACE_START)
156 new_space = (lispobj *) DYNAMIC_0_SPACE_START;
158 lose("GC lossage. Current dynamic space is bogus!\n");
160 new_space_free_pointer = new_space;
162 /* Initialize the weak pointer list. */
163 weak_pointers = (struct weak_pointer *) NULL;
166 /* Scavenge all of the roots. */
168 printf("Scavenging interrupt contexts ...\n");
170 scavenge_interrupt_contexts();
173 printf("Scavenging interrupt handlers (%d bytes) ...\n",
174 (int)sizeof(interrupt_handlers));
176 scavenge((lispobj *) interrupt_handlers,
177 sizeof(interrupt_handlers) / sizeof(lispobj));
179 /* _size quantities are in units of sizeof(lispobj) - i.e. 4 */
181 current_control_stack_pointer-
182 (lispobj *)th->control_stack_start;
184 printf("Scavenging the control stack at %p (%ld words) ...\n",
185 ((lispobj *)th->control_stack_start),
188 scavenge(((lispobj *)th->control_stack_start), control_stack_size);
192 current_binding_stack_pointer -
193 (lispobj *)th->binding_stack_start;
195 printf("Scavenging the binding stack %x - %x (%d words) ...\n",
196 th->binding_stack_start,current_binding_stack_pointer,
197 (int)(binding_stack_size));
199 scavenge(((lispobj *)th->binding_stack_start), binding_stack_size);
202 current_static_space_free_pointer - (lispobj *) STATIC_SPACE_START;
204 printf("Scavenging static space %x - %x (%d words) ...\n",
205 STATIC_SPACE_START,current_static_space_free_pointer,
206 (int)(static_space_size));
208 scavenge(((lispobj *)STATIC_SPACE_START), static_space_size);
210 /* Scavenge newspace. */
212 printf("Scavenging new space (%d bytes) ...\n",
213 (int)((new_space_free_pointer - new_space) * sizeof(lispobj)));
218 #if defined(DEBUG_PRINT_GARBAGE)
219 print_garbage(from_space, from_space_free_pointer);
222 /* Scan the weak pointers. */
224 printf("Scanning weak hash tables ...\n");
226 scan_weak_hash_tables();
228 /* Scan the weak pointers. */
230 printf("Scanning weak pointers ...\n");
232 scan_weak_pointers();
236 printf("Flipping spaces ...\n");
239 /* Maybe FIXME: it's possible that we could significantly reduce
240 * RSS by zeroing the from_space or madvise(MADV_DONTNEED) or
241 * similar os-dependent tricks here */
242 os_zero((os_vm_address_t) from_space,
243 (os_vm_size_t) dynamic_space_size);
245 current_dynamic_space = new_space;
246 dynamic_space_free_pointer = new_space_free_pointer;
249 size_discarded = (from_space_free_pointer - from_space) * sizeof(lispobj);
251 size_retained = (new_space_free_pointer - new_space) * sizeof(lispobj);
253 os_flush_icache((os_vm_address_t)new_space, size_retained);
257 printf("Zeroing empty part of control stack ...\n");
260 set_auto_gc_trigger(size_retained+bytes_consed_between_gcs);
261 thread_sigmask(SIG_SETMASK, &old, 0);
265 gettimeofday(&stop_tv, (struct timezone *) 0);
266 getrusage(RUSAGE_SELF, &stop_rusage);
270 percent_retained = (((float) size_retained) /
271 ((float) size_discarded)) * 100.0;
273 printf("Total of %ld bytes out of %ld bytes retained (%3.2f%%).\n",
274 size_retained, size_discarded, percent_retained);
276 real_time = tv_diff(&stop_tv, &start_tv);
277 user_time = tv_diff(&stop_rusage.ru_utime, &start_rusage.ru_utime);
278 system_time = tv_diff(&stop_rusage.ru_stime, &start_rusage.ru_stime);
280 printf("Statistics: %10.2fs real, %10.2fs user, %10.2fs system.\n",
281 real_time, user_time, system_time);
283 gc_rate = ((float) size_retained / (float) (1<<20)) / real_time;
285 printf("%10.2f M bytes/sec collected.\n", gc_rate);
293 scavenge_newspace(void)
295 lispobj *here, *next;
298 while (here < new_space_free_pointer) {
299 /* printf("here=%lx, new_space_free_pointer=%lx\n",
300 here,new_space_free_pointer); */
301 next = new_space_free_pointer;
302 scavenge(here, next - here);
303 scav_weak_hash_tables();
306 /* printf("done with newspace\n"); */
309 /* scavenging interrupt contexts */
311 static int boxed_registers[] = BOXED_REGISTERS;
314 scavenge_interrupt_context(os_context_t *context)
319 unsigned long lip_offset;
320 int lip_register_pair;
322 unsigned long pc_code_offset;
323 #ifdef ARCH_HAS_LINK_REGISTER
324 unsigned long lr_code_offset;
326 #ifdef ARCH_HAS_NPC_REGISTER
327 unsigned long npc_code_offset;
329 #ifdef DEBUG_SCAVENGE_VERBOSE
330 fprintf(stderr, "Scavenging interrupt context at 0x%x\n",context);
332 /* Find the LIP's register pair and calculate its offset */
333 /* before we scavenge the context. */
335 lip = *os_context_register_addr(context, reg_LIP);
336 /* 0x7FFFFFFF on 32-bit platforms;
337 0x7FFFFFFFFFFFFFFF on 64-bit platforms */
338 lip_offset = (((unsigned long)1) << (N_WORD_BITS - 1)) - 1;
339 lip_register_pair = -1;
340 for (i = 0; i < (int)(sizeof(boxed_registers) / sizeof(int)); i++) {
342 unsigned long offset;
345 index = boxed_registers[i];
346 reg = *os_context_register_addr(context, index);
347 /* would be using PTR if not for integer length issues */
348 if ((reg & ~((1L<<N_LOWTAG_BITS)-1)) <= lip) {
350 if (offset < lip_offset) {
352 lip_register_pair = index;
358 /* Compute the PC's offset from the start of the CODE */
361 *os_context_pc_addr(context) -
362 *os_context_register_addr(context, reg_CODE);
363 #ifdef ARCH_HAS_NPC_REGISTER
365 *os_context_npc_addr(context) -
366 *os_context_register_addr(context, reg_CODE);
368 #ifdef ARCH_HAS_LINK_REGISTER
370 *os_context_lr_addr(context) -
371 *os_context_register_addr(context, reg_CODE);
374 /* Scavenge all boxed registers in the context. */
375 for (i = 0; i < (int)(sizeof(boxed_registers) / sizeof(int)); i++) {
379 index = boxed_registers[i];
380 foo = *os_context_register_addr(context,index);
381 scavenge((lispobj *) &foo, 1);
382 *os_context_register_addr(context,index) = foo;
384 /* this is unlikely to work as intended on bigendian
385 * 64 bit platforms */
388 os_context_register_addr(context, index), 1);
393 *os_context_register_addr(context, reg_LIP) =
394 *os_context_register_addr(context, lip_register_pair) + lip_offset;
397 /* Fix the PC if it was in from space */
398 if (from_space_p(*os_context_pc_addr(context)))
399 *os_context_pc_addr(context) =
400 *os_context_register_addr(context, reg_CODE) + pc_code_offset;
401 #ifdef ARCH_HAS_LINK_REGISTER
402 /* Fix the LR ditto; important if we're being called from
403 * an assembly routine that expects to return using blr, otherwise
405 if (from_space_p(*os_context_lr_addr(context)))
406 *os_context_lr_addr(context) =
407 *os_context_register_addr(context, reg_CODE) + lr_code_offset;
410 #ifdef ARCH_HAS_NPC_REGISTER
411 if (from_space_p(*os_context_npc_addr(context)))
412 *os_context_npc_addr(context) =
413 *os_context_register_addr(context, reg_CODE) + npc_code_offset;
417 void scavenge_interrupt_contexts(void)
420 os_context_t *context;
422 struct thread *th=arch_os_get_current_thread();
424 index = fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,0));
427 #ifdef DEBUG_SCAVENGE_VERBOSE
428 fprintf(stderr, "%d interrupt contexts to scan\n",index);
430 for (i = 0; i < index; i++) {
431 context = th->interrupt_contexts[i];
432 scavenge_interrupt_context(context);
440 print_garbage(lispobj *from_space, lispobj *from_space_free_pointer)
443 int total_words_not_copied;
445 printf("Scanning from space ...\n");
447 total_words_not_copied = 0;
449 while (start < from_space_free_pointer) {
451 int forwardp, type, nwords;
455 forwardp = is_lisp_pointer(object) && new_space_p(object);
461 tag = lowtag_of(object);
464 case LIST_POINTER_LOWTAG:
467 case INSTANCE_POINTER_LOWTAG:
468 printf("Don't know about instances yet!\n");
471 case FUN_POINTER_LOWTAG:
474 case OTHER_POINTER_LOWTAG:
475 pointer = (lispobj *) native_pointer(object);
477 type = widetag_of(header);
478 nwords = (sizetab[type])(pointer);
480 default: nwords=1; /* shut yer whinging, gcc */
483 type = widetag_of(object);
484 nwords = (sizetab[type])(start);
485 total_words_not_copied += nwords;
486 printf("%4d words not copied at 0x%16lx; ",
487 nwords, (unsigned long) start);
488 printf("Header word is 0x%08x\n",
489 (unsigned int) object);
493 printf("%d total words not copied.\n", total_words_not_copied);
499 #define WEAK_POINTER_NWORDS \
500 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
503 scav_weak_pointer(lispobj *where, lispobj object)
505 /* Do not let GC scavenge the value slot of the weak pointer */
506 /* (that is why it is a weak pointer). Note: we could use */
507 /* the scav_unboxed method here. */
509 return WEAK_POINTER_NWORDS;
513 search_read_only_space(void *pointer)
515 lispobj* start = (lispobj*)READ_ONLY_SPACE_START;
516 lispobj* end = (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
517 if ((pointer < (void *)start) || (pointer >= (void *)end))
519 return (gc_search_space(start,
520 (((lispobj *)pointer)+2)-start,
521 (lispobj *)pointer));
525 search_static_space(void *pointer)
527 lispobj* start = (lispobj*)STATIC_SPACE_START;
528 lispobj* end = (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
529 if ((pointer < (void *)start) || (pointer >= (void *)end))
531 return (gc_search_space(start,
532 (((lispobj *)pointer)+2)-start,
533 (lispobj *)pointer));
537 search_dynamic_space(void *pointer)
539 lispobj *start = (lispobj *) current_dynamic_space;
540 lispobj *end = (lispobj *) dynamic_space_free_pointer;
541 if ((pointer < (void *)start) || (pointer >= (void *)end))
543 return (gc_search_space(start,
544 (((lispobj *)pointer)+2)-start,
545 (lispobj *)pointer));
548 /* initialization. if gc_init can be moved to after core load, we could
549 * combine these two functions */
555 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
559 gc_initialize_pointers(void)
561 /* FIXME: We do nothing here. We (briefly) misguidedly attempted
562 to set current_dynamic_space to DYNAMIC_0_SPACE_START here,
563 forgetting that (a) actually it could be the other and (b) it's
564 set in coreparse.c anyway. There's a FIXME note left here to
565 note that current_dynamic_space is a violation of OAOO: we can
566 tell which dynamic space we're currently in by looking at
567 dynamic_space_free_pointer. -- CSR, 2002-08-09 */
573 /* noise to manipulate the gc trigger stuff */
575 /* Functions that substantially change the dynamic space free pointer
576 * (collect_garbage, purify) are responsible also for resetting the
578 void set_auto_gc_trigger(os_vm_size_t dynamic_usage)
580 os_vm_address_t addr;
583 addr = os_round_up_to_page((os_vm_address_t)current_dynamic_space
585 if (addr < (os_vm_address_t)dynamic_space_free_pointer)
586 lose("set_auto_gc_trigger: tried to set gc trigger too low! (%ld < 0x%08lx)\n",
587 (unsigned long)dynamic_usage,
588 (unsigned long)((os_vm_address_t)dynamic_space_free_pointer
589 - (os_vm_address_t)current_dynamic_space));
591 length = os_trunc_size_to_page(dynamic_space_size - dynamic_usage);
593 lose("set_auto_gc_trigger: tried to set gc trigger too high! (0x%08lx)\n",
594 (unsigned long)dynamic_usage);
596 #if defined(SUNOS) || defined(SOLARIS)
597 os_invalidate(addr, length);
599 os_protect(addr, length, 0);
602 current_auto_gc_trigger = (lispobj *)addr;
605 void clear_auto_gc_trigger(void)
607 os_vm_address_t addr;
610 if (current_auto_gc_trigger == NULL)
613 addr = (os_vm_address_t)current_auto_gc_trigger;
614 length = dynamic_space_size + (os_vm_address_t)current_dynamic_space - addr;
616 #if defined(SUNOS) || defined(SOLARIS)
617 /* don't want to force whole space into swapping mode... */
618 os_validate(addr, length);
620 os_protect(addr, length, OS_VM_PROT_ALL);
623 current_auto_gc_trigger = NULL;
627 gc_trigger_hit(void *addr)
629 if (current_auto_gc_trigger == NULL)
632 return (addr >= (void *)current_auto_gc_trigger &&
633 addr <((void *)current_dynamic_space + dynamic_space_size));
638 cheneygc_handle_wp_violation(os_context_t *context, void *addr)
640 if(!foreign_function_call_active && gc_trigger_hit(addr)){
641 struct thread *thread=arch_os_get_current_thread();
642 clear_auto_gc_trigger();
643 /* Don't flood the system with interrupts if the need to gc is
644 * already noted. This can happen for example when SUB-GC
645 * allocates or after a gc triggered in a WITHOUT-GCING. */
646 if (SymbolValue(GC_PENDING,thread) == NIL) {
647 if (SymbolValue(GC_INHIBIT,thread) == NIL) {
648 if (arch_pseudo_atomic_atomic(context)) {
649 /* set things up so that GC happens when we finish
651 SetSymbolValue(GC_PENDING,T,thread);
652 arch_set_pseudo_atomic_interrupted(context);
657 SetSymbolValue(GC_PENDING,T,thread);