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"
34 /* So you need to debug? */
37 #define DEBUG_SPACE_PREDICATES
38 #define DEBUG_SCAVENGE_VERBOSE
39 #define DEBUG_COPY_VERBOSE
44 lispobj *from_space_free_pointer;
47 lispobj *new_space_free_pointer;
49 static void scavenge_newspace(void);
51 extern unsigned long bytes_consed_between_gcs;
54 /* collecting garbage */
58 tv_diff(struct timeval *x, struct timeval *y)
60 return (((double) x->tv_sec + (double) x->tv_usec * 1.0e-6) -
61 ((double) y->tv_sec + (double) y->tv_usec * 1.0e-6));
65 #define BYTES_ZERO_BEFORE_END (1<<12)
67 /* FIXME do we need this? Doesn't it duplicate lisp code in
68 * scrub-control-stack? */
73 lispobj *ptr = current_control_stack_pointer;
79 } while (((unsigned long)ptr) & (BYTES_ZERO_BEFORE_END-1));
84 } while (((unsigned long)ptr) & (BYTES_ZERO_BEFORE_END-1));
91 gc_general_alloc(long bytes, int unboxed_p, int quick_p) {
92 lispobj *new=new_space_free_pointer;
93 new_space_free_pointer+=(bytes/N_WORD_BYTES);
97 lispobj copy_large_unboxed_object(lispobj object, long nwords) {
98 return copy_object(object,nwords);
100 lispobj copy_unboxed_object(lispobj object, long nwords) {
101 return copy_object(object,nwords);
103 lispobj copy_large_object(lispobj object, long nwords) {
104 return copy_object(object,nwords);
107 /* Note: The generic GC interface we're implementing passes us a
108 * last_generation argument. That's meaningless for us, since we're
109 * not a generational GC. So we ignore it. */
111 collect_garbage(generation_index_t ignore)
114 struct timeval start_tv, stop_tv;
115 struct rusage start_rusage, stop_rusage;
116 double real_time, system_time, user_time;
117 double percent_retained, gc_rate;
118 unsigned long size_discarded;
120 unsigned long size_retained;
121 lispobj *current_static_space_free_pointer;
122 unsigned long static_space_size;
123 unsigned long control_stack_size, binding_stack_size;
125 struct thread *th=arch_os_get_current_thread();
128 printf("[Collecting garbage ... \n");
130 getrusage(RUSAGE_SELF, &start_rusage);
131 gettimeofday(&start_tv, (struct timezone *) 0);
134 /* it's possible that signals are blocked already if this was called
135 * from a signal handler (e.g. with the sigsegv gc_trigger stuff) */
137 sigaddset_blockable(&tmp);
138 thread_sigmask(SIG_BLOCK, &tmp, &old);
140 current_static_space_free_pointer =
141 (lispobj *) ((unsigned long)
142 SymbolValue(STATIC_SPACE_FREE_POINTER,0));
145 /* Set up from space and new space pointers. */
147 from_space = current_dynamic_space;
148 from_space_free_pointer = dynamic_space_free_pointer;
151 fprintf(stderr,"from_space = %lx\n",
152 (unsigned long) current_dynamic_space);
154 if (current_dynamic_space == (lispobj *) DYNAMIC_0_SPACE_START)
155 new_space = (lispobj *)DYNAMIC_1_SPACE_START;
156 else if (current_dynamic_space == (lispobj *) DYNAMIC_1_SPACE_START)
157 new_space = (lispobj *) DYNAMIC_0_SPACE_START;
159 lose("GC lossage. Current dynamic space is bogus!\n");
161 new_space_free_pointer = new_space;
163 /* Initialize the weak pointer list. */
164 weak_pointers = (struct weak_pointer *) NULL;
167 /* Scavenge all of the roots. */
169 printf("Scavenging interrupt contexts ...\n");
171 scavenge_interrupt_contexts();
174 printf("Scavenging interrupt handlers (%d bytes) ...\n",
175 (int)sizeof(interrupt_handlers));
177 scavenge((lispobj *) interrupt_handlers,
178 sizeof(interrupt_handlers) / sizeof(lispobj));
180 /* _size quantities are in units of sizeof(lispobj) - i.e. 4 */
182 current_control_stack_pointer-
183 (lispobj *)th->control_stack_start;
185 printf("Scavenging the control stack at %p (%ld words) ...\n",
186 ((lispobj *)th->control_stack_start),
189 scavenge(((lispobj *)th->control_stack_start), control_stack_size);
193 current_binding_stack_pointer -
194 (lispobj *)th->binding_stack_start;
196 printf("Scavenging the binding stack %x - %x (%d words) ...\n",
197 th->binding_stack_start,current_binding_stack_pointer,
198 (int)(binding_stack_size));
200 scavenge(((lispobj *)th->binding_stack_start), binding_stack_size);
203 current_static_space_free_pointer - (lispobj *) STATIC_SPACE_START;
205 printf("Scavenging static space %x - %x (%d words) ...\n",
206 STATIC_SPACE_START,current_static_space_free_pointer,
207 (int)(static_space_size));
209 scavenge(((lispobj *)STATIC_SPACE_START), static_space_size);
211 /* Scavenge newspace. */
213 printf("Scavenging new space (%d bytes) ...\n",
214 (int)((new_space_free_pointer - new_space) * sizeof(lispobj)));
219 #if defined(DEBUG_PRINT_GARBAGE)
220 print_garbage(from_space, from_space_free_pointer);
223 /* Scan the weak pointers. */
225 printf("Scanning weak pointers ...\n");
227 scan_weak_pointers();
232 printf("Flipping spaces ...\n");
235 /* Maybe FIXME: it's possible that we could significantly reduce
236 * RSS by zeroing the from_space or madvise(MADV_DONTNEED) or
237 * similar os-dependent tricks here */
238 os_zero((os_vm_address_t) from_space,
239 (os_vm_size_t) DYNAMIC_SPACE_SIZE);
241 current_dynamic_space = new_space;
242 dynamic_space_free_pointer = new_space_free_pointer;
245 size_discarded = (from_space_free_pointer - from_space) * sizeof(lispobj);
247 size_retained = (new_space_free_pointer - new_space) * sizeof(lispobj);
249 os_flush_icache((os_vm_address_t)new_space, size_retained);
253 printf("Zeroing empty part of control stack ...\n");
256 set_auto_gc_trigger(size_retained+bytes_consed_between_gcs);
257 thread_sigmask(SIG_SETMASK, &old, 0);
261 gettimeofday(&stop_tv, (struct timezone *) 0);
262 getrusage(RUSAGE_SELF, &stop_rusage);
266 percent_retained = (((float) size_retained) /
267 ((float) size_discarded)) * 100.0;
269 printf("Total of %ld bytes out of %ld bytes retained (%3.2f%%).\n",
270 size_retained, size_discarded, percent_retained);
272 real_time = tv_diff(&stop_tv, &start_tv);
273 user_time = tv_diff(&stop_rusage.ru_utime, &start_rusage.ru_utime);
274 system_time = tv_diff(&stop_rusage.ru_stime, &start_rusage.ru_stime);
276 printf("Statistics: %10.2fs real, %10.2fs user, %10.2fs system.\n",
277 real_time, user_time, system_time);
279 gc_rate = ((float) size_retained / (float) (1<<20)) / real_time;
281 printf("%10.2f M bytes/sec collected.\n", gc_rate);
289 scavenge_newspace(void)
291 lispobj *here, *next;
294 while (here < new_space_free_pointer) {
295 /* printf("here=%lx, new_space_free_pointer=%lx\n",
296 here,new_space_free_pointer); */
297 next = new_space_free_pointer;
298 scavenge(here, next - here);
301 /* printf("done with newspace\n"); */
304 /* scavenging interrupt contexts */
306 static int boxed_registers[] = BOXED_REGISTERS;
309 scavenge_interrupt_context(os_context_t *context)
314 unsigned long lip_offset;
315 int lip_register_pair;
317 unsigned long pc_code_offset;
318 #ifdef ARCH_HAS_LINK_REGISTER
319 unsigned long lr_code_offset;
321 #ifdef ARCH_HAS_NPC_REGISTER
322 unsigned long npc_code_offset;
324 #ifdef DEBUG_SCAVENGE_VERBOSE
325 fprintf(stderr, "Scavenging interrupt context at 0x%x\n",context);
327 /* Find the LIP's register pair and calculate its offset */
328 /* before we scavenge the context. */
330 lip = *os_context_register_addr(context, reg_LIP);
331 /* 0x7FFFFFFF on 32-bit platforms;
332 0x7FFFFFFFFFFFFFFF on 64-bit platforms */
333 lip_offset = (((unsigned long)1) << (N_WORD_BITS - 1)) - 1;
334 lip_register_pair = -1;
335 for (i = 0; i < (sizeof(boxed_registers) / sizeof(int)); i++) {
340 index = boxed_registers[i];
341 reg = *os_context_register_addr(context, index);
342 /* would be using PTR if not for integer length issues */
343 if ((reg & ~((1L<<N_LOWTAG_BITS)-1)) <= lip) {
345 if (offset < lip_offset) {
347 lip_register_pair = index;
353 /* Compute the PC's offset from the start of the CODE */
356 *os_context_pc_addr(context) -
357 *os_context_register_addr(context, reg_CODE);
358 #ifdef ARCH_HAS_NPC_REGISTER
360 *os_context_npc_addr(context) -
361 *os_context_register_addr(context, reg_CODE);
363 #ifdef ARCH_HAS_LINK_REGISTER
365 *os_context_lr_addr(context) -
366 *os_context_register_addr(context, reg_CODE);
369 /* Scavenge all boxed registers in the context. */
370 for (i = 0; i < (sizeof(boxed_registers) / sizeof(int)); i++) {
374 index = boxed_registers[i];
375 foo = *os_context_register_addr(context,index);
376 scavenge((lispobj *) &foo, 1);
377 *os_context_register_addr(context,index) = foo;
379 /* this is unlikely to work as intended on bigendian
380 * 64 bit platforms */
383 os_context_register_addr(context, index), 1);
388 *os_context_register_addr(context, reg_LIP) =
389 *os_context_register_addr(context, lip_register_pair) + lip_offset;
392 /* Fix the PC if it was in from space */
393 if (from_space_p(*os_context_pc_addr(context)))
394 *os_context_pc_addr(context) =
395 *os_context_register_addr(context, reg_CODE) + pc_code_offset;
396 #ifdef ARCH_HAS_LINK_REGISTER
397 /* Fix the LR ditto; important if we're being called from
398 * an assembly routine that expects to return using blr, otherwise
400 if (from_space_p(*os_context_lr_addr(context)))
401 *os_context_lr_addr(context) =
402 *os_context_register_addr(context, reg_CODE) + lr_code_offset;
405 #ifdef ARCH_HAS_NPC_REGISTER
406 if (from_space_p(*os_context_npc_addr(context)))
407 *os_context_npc_addr(context) =
408 *os_context_register_addr(context, reg_CODE) + npc_code_offset;
412 void scavenge_interrupt_contexts(void)
415 os_context_t *context;
417 struct thread *th=arch_os_get_current_thread();
419 index = fixnum_value(SymbolValue(FREE_INTERRUPT_CONTEXT_INDEX,0));
422 #ifdef DEBUG_SCAVENGE_VERBOSE
423 fprintf(stderr, "%d interrupt contexts to scan\n",index);
425 for (i = 0; i < index; i++) {
426 context = th->interrupt_contexts[i];
427 scavenge_interrupt_context(context);
435 print_garbage(lispobj *from_space, lispobj *from_space_free_pointer)
438 int total_words_not_copied;
440 printf("Scanning from space ...\n");
442 total_words_not_copied = 0;
444 while (start < from_space_free_pointer) {
446 int forwardp, type, nwords;
450 forwardp = is_lisp_pointer(object) && new_space_p(object);
456 tag = lowtag_of(object);
459 case LIST_POINTER_LOWTAG:
462 case INSTANCE_POINTER_LOWTAG:
463 printf("Don't know about instances yet!\n");
466 case FUN_POINTER_LOWTAG:
469 case OTHER_POINTER_LOWTAG:
470 pointer = (lispobj *) native_pointer(object);
472 type = widetag_of(header);
473 nwords = (sizetab[type])(pointer);
475 default: nwords=1; /* shut yer whinging, gcc */
478 type = widetag_of(object);
479 nwords = (sizetab[type])(start);
480 total_words_not_copied += nwords;
481 printf("%4d words not copied at 0x%16lx; ",
482 nwords, (unsigned long) start);
483 printf("Header word is 0x%08x\n",
484 (unsigned int) object);
488 printf("%d total words not copied.\n", total_words_not_copied);
492 /* vector-like objects */
495 scav_vector(lispobj *where, lispobj object)
497 if (HeaderValue(object) == subtype_VectorValidHashing) {
499 (subtype_VectorMustRehash<<N_WIDETAG_BITS) | SIMPLE_VECTOR_WIDETAG;
508 #define WEAK_POINTER_NWORDS \
509 CEILING((sizeof(struct weak_pointer) / sizeof(lispobj)), 2)
512 scav_weak_pointer(lispobj *where, lispobj object)
514 /* Do not let GC scavenge the value slot of the weak pointer */
515 /* (that is why it is a weak pointer). Note: we could use */
516 /* the scav_unboxed method here. */
518 return WEAK_POINTER_NWORDS;
522 search_read_only_space(void *pointer)
524 lispobj* start = (lispobj*)READ_ONLY_SPACE_START;
525 lispobj* end = (lispobj*)SymbolValue(READ_ONLY_SPACE_FREE_POINTER,0);
526 if ((pointer < (void *)start) || (pointer >= (void *)end))
528 return (gc_search_space(start,
529 (((lispobj *)pointer)+2)-start,
530 (lispobj *)pointer));
534 search_static_space(void *pointer)
536 lispobj* start = (lispobj*)STATIC_SPACE_START;
537 lispobj* end = (lispobj*)SymbolValue(STATIC_SPACE_FREE_POINTER,0);
538 if ((pointer < (void *)start) || (pointer >= (void *)end))
540 return (gc_search_space(start,
541 (((lispobj *)pointer)+2)-start,
542 (lispobj *)pointer));
546 search_dynamic_space(void *pointer)
548 lispobj *start = (lispobj *) current_dynamic_space;
549 lispobj *end = (lispobj *) dynamic_space_free_pointer;
550 if ((pointer < (void *)start) || (pointer >= (void *)end))
552 return (gc_search_space(start,
553 (((lispobj *)pointer)+2)-start,
554 (lispobj *)pointer));
557 /* initialization. if gc_init can be moved to after core load, we could
558 * combine these two functions */
564 scavtab[SIMPLE_VECTOR_WIDETAG] = scav_vector;
565 scavtab[WEAK_POINTER_WIDETAG] = scav_weak_pointer;
569 gc_initialize_pointers(void)
571 /* FIXME: We do nothing here. We (briefly) misguidedly attempted
572 to set current_dynamic_space to DYNAMIC_0_SPACE_START here,
573 forgetting that (a) actually it could be the other and (b) it's
574 set in coreparse.c anyway. There's a FIXME note left here to
575 note that current_dynamic_space is a violation of OAOO: we can
576 tell which dynamic space we're currently in by looking at
577 dynamic_space_free_pointer. -- CSR, 2002-08-09 */
583 /* noise to manipulate the gc trigger stuff */
585 /* Functions that substantially change the dynamic space free pointer
586 * (collect_garbage, purify) are responsible also for resetting the
588 void set_auto_gc_trigger(os_vm_size_t dynamic_usage)
590 os_vm_address_t addr;
593 addr = os_round_up_to_page((os_vm_address_t)current_dynamic_space
595 if (addr < (os_vm_address_t)dynamic_space_free_pointer)
596 lose("set_auto_gc_trigger: tried to set gc trigger too low! (%ld < 0x%08lx)\n",
597 (unsigned long)dynamic_usage,
598 (unsigned long)((os_vm_address_t)dynamic_space_free_pointer
599 - (os_vm_address_t)current_dynamic_space));
601 length = os_trunc_size_to_page(DYNAMIC_SPACE_SIZE - dynamic_usage);
603 lose("set_auto_gc_trigger: tried to set gc trigger too high! (0x%08lx)\n",
604 (unsigned long)dynamic_usage);
606 #if defined(SUNOS) || defined(SOLARIS)
607 os_invalidate(addr, length);
609 os_protect(addr, length, 0);
612 current_auto_gc_trigger = (lispobj *)addr;
615 void clear_auto_gc_trigger(void)
617 os_vm_address_t addr;
620 if (current_auto_gc_trigger == NULL)
623 addr = (os_vm_address_t)current_auto_gc_trigger;
624 length = DYNAMIC_SPACE_SIZE + (os_vm_address_t)current_dynamic_space - addr;
626 #if defined(SUNOS) || defined(SOLARIS)
627 /* don't want to force whole space into swapping mode... */
628 os_validate(addr, length);
630 os_protect(addr, length, OS_VM_PROT_ALL);
633 current_auto_gc_trigger = NULL;