1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.c,v 1.43 2001/08/07 09:20:52 simonmar Exp $
4 * (c) The GHC Team, 1998-1999
6 * Storage manager front end
8 * ---------------------------------------------------------------------------*/
15 #include "BlockAlloc.h"
22 #include "StoragePriv.h"
25 nat nursery_blocks; /* number of blocks in the nursery */
28 StgClosure *caf_list = NULL;
30 bdescr *small_alloc_list; /* allocate()d small objects */
31 bdescr *large_alloc_list; /* allocate()d large objects */
32 nat alloc_blocks; /* number of allocate()d blocks since GC */
33 nat alloc_blocks_lim; /* approximate limit on alloc_blocks */
35 StgPtr alloc_Hp = NULL; /* next free byte in small_alloc_list */
36 StgPtr alloc_HpLim = NULL; /* end of block at small_alloc_list */
38 generation *generations; /* all the generations */
39 generation *g0; /* generation 0, for convenience */
40 generation *oldest_gen; /* oldest generation, for convenience */
41 step *g0s0; /* generation 0, step 0, for convenience */
43 lnat total_allocated = 0; /* total memory allocated during run */
46 * Storage manager mutex: protects all the above state from
47 * simultaneous access by two STG threads.
50 pthread_mutex_t sm_mutex = PTHREAD_MUTEX_INITIALIZER;
56 static void *stgAllocForGMP (size_t size_in_bytes);
57 static void *stgReallocForGMP (void *ptr, size_t old_size, size_t new_size);
58 static void stgDeallocForGMP (void *ptr, size_t size);
67 /* If we're doing heap profiling, we want a two-space heap with a
68 * fixed-size allocation area so that we get roughly even-spaced
72 /* As an experiment, try a 2 generation collector
75 #if defined(PROFILING) || defined(DEBUG)
76 if (RtsFlags.ProfFlags.doHeapProfile) {
77 RtsFlags.GcFlags.generations = 1;
78 RtsFlags.GcFlags.steps = 1;
79 RtsFlags.GcFlags.oldGenFactor = 0;
80 RtsFlags.GcFlags.heapSizeSuggestion = 0;
84 if (RtsFlags.GcFlags.heapSizeSuggestion >
85 RtsFlags.GcFlags.maxHeapSize) {
86 RtsFlags.GcFlags.maxHeapSize = RtsFlags.GcFlags.heapSizeSuggestion;
91 /* allocate generation info array */
92 generations = (generation *)stgMallocBytes(RtsFlags.GcFlags.generations
93 * sizeof(struct _generation),
96 /* Initialise all generations */
97 for(g = 0; g < RtsFlags.GcFlags.generations; g++) {
98 gen = &generations[g];
100 gen->mut_list = END_MUT_LIST;
101 gen->mut_once_list = END_MUT_LIST;
102 gen->collections = 0;
103 gen->failed_promotions = 0;
107 /* A couple of convenience pointers */
108 g0 = &generations[0];
109 oldest_gen = &generations[RtsFlags.GcFlags.generations-1];
111 /* Allocate step structures in each generation */
112 if (RtsFlags.GcFlags.generations > 1) {
113 /* Only for multiple-generations */
115 /* Oldest generation: one step */
116 oldest_gen->n_steps = 1;
118 stgMallocBytes(1 * sizeof(struct _step), "initStorage: last step");
120 /* set up all except the oldest generation with 2 steps */
121 for(g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
122 generations[g].n_steps = RtsFlags.GcFlags.steps;
123 generations[g].steps =
124 stgMallocBytes (RtsFlags.GcFlags.steps * sizeof(struct _step),
125 "initStorage: steps");
129 /* single generation, i.e. a two-space collector */
131 g0->steps = stgMallocBytes (sizeof(struct _step), "initStorage: steps");
134 /* Initialise all steps */
135 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
136 for (s = 0; s < generations[g].n_steps; s++) {
137 stp = &generations[g].steps[s];
141 stp->gen = &generations[g];
148 stp->large_objects = NULL;
149 stp->new_large_objects = NULL;
150 stp->scavenged_large_objects = NULL;
151 stp->is_compacted = 0;
155 /* Set up the destination pointers in each younger gen. step */
156 for (g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
157 for (s = 0; s < generations[g].n_steps-1; s++) {
158 generations[g].steps[s].to = &generations[g].steps[s+1];
160 generations[g].steps[s].to = &generations[g+1].steps[0];
163 /* The oldest generation has one step. */
164 oldest_gen->steps[0].to = &oldest_gen->steps[0];
166 /* generation 0 is special: that's the nursery */
167 generations[0].max_blocks = 0;
169 /* G0S0: the allocation area. Policy: keep the allocation area
170 * small to begin with, even if we have a large suggested heap
171 * size. Reason: we're going to do a major collection first, and we
172 * don't want it to be a big one. This vague idea is borne out by
173 * rigorous experimental evidence.
175 g0s0 = &generations[0].steps[0];
179 weak_ptr_list = NULL;
182 /* initialise the allocate() interface */
183 small_alloc_list = NULL;
184 large_alloc_list = NULL;
186 alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
188 /* Tell GNU multi-precision pkg about our custom alloc functions */
189 mp_set_memory_functions(stgAllocForGMP, stgReallocForGMP, stgDeallocForGMP);
192 pthread_mutex_init(&sm_mutex, NULL);
195 IF_DEBUG(gc, statDescribeGens());
201 stat_exit(calcAllocated());
204 /* -----------------------------------------------------------------------------
207 The entry code for every CAF does the following:
209 - builds a CAF_BLACKHOLE in the heap
210 - pushes an update frame pointing to the CAF_BLACKHOLE
211 - invokes UPD_CAF(), which:
212 - calls newCaf, below
213 - updates the CAF with a static indirection to the CAF_BLACKHOLE
215 Why do we build a BLACKHOLE in the heap rather than just updating
216 the thunk directly? It's so that we only need one kind of update
217 frame - otherwise we'd need a static version of the update frame too.
219 newCaf() does the following:
221 - it puts the CAF on the oldest generation's mut-once list.
222 This is so that we can treat the CAF as a root when collecting
225 For GHCI, we have additional requirements when dealing with CAFs:
227 - we must *retain* all dynamically-loaded CAFs ever entered,
228 just in case we need them again.
229 - we must be able to *revert* CAFs that have been evaluated, to
230 their pre-evaluated form.
232 To do this, we use an additional CAF list. When newCaf() is
233 called on a dynamically-loaded CAF, we add it to the CAF list
234 instead of the old-generation mutable list, and save away its
235 old info pointer (in caf->saved_info) for later reversion.
237 To revert all the CAFs, we traverse the CAF list and reset the
238 info pointer to caf->saved_info, then throw away the CAF list.
239 (see GC.c:revertCAFs()).
243 -------------------------------------------------------------------------- */
246 newCAF(StgClosure* caf)
248 /* Put this CAF on the mutable list for the old generation.
249 * This is a HACK - the IND_STATIC closure doesn't really have
250 * a mut_link field, but we pretend it has - in fact we re-use
251 * the STATIC_LINK field for the time being, because when we
252 * come to do a major GC we won't need the mut_link field
253 * any more and can use it as a STATIC_LINK.
255 ACQUIRE_LOCK(&sm_mutex);
257 if (is_dynamically_loaded_rwdata_ptr((StgPtr)caf)) {
258 ((StgIndStatic *)caf)->saved_info = (StgInfoTable *)caf->header.info;
259 ((StgIndStatic *)caf)->static_link = caf_list;
262 ((StgIndStatic *)caf)->saved_info = NULL;
263 ((StgMutClosure *)caf)->mut_link = oldest_gen->mut_once_list;
264 oldest_gen->mut_once_list = (StgMutClosure *)caf;
267 RELEASE_LOCK(&sm_mutex);
270 /* If we are PAR or DIST then we never forget a CAF */
272 //belch("<##> Globalising CAF %08x %s",caf,info_type(caf));
273 newGA=makeGlobal(caf,rtsTrue); /*given full weight*/
279 /* -----------------------------------------------------------------------------
281 -------------------------------------------------------------------------- */
284 allocNurseries( void )
293 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
294 cap->rNursery = allocNursery(NULL, RtsFlags.GcFlags.minAllocAreaSize);
295 cap->rCurrentNursery = cap->rNursery;
296 for (bd = cap->rNursery; bd != NULL; bd = bd->link) {
297 bd->u.back = (bdescr *)cap;
300 /* Set the back links to be equal to the Capability,
301 * so we can do slightly better informed locking.
305 nursery_blocks = RtsFlags.GcFlags.minAllocAreaSize;
306 g0s0->blocks = allocNursery(NULL, nursery_blocks);
307 g0s0->n_blocks = nursery_blocks;
308 g0s0->to_blocks = NULL;
309 g0s0->n_to_blocks = 0;
310 MainRegTable.rNursery = g0s0->blocks;
311 MainRegTable.rCurrentNursery = g0s0->blocks;
312 /* hp, hpLim, hp_bd, to_space etc. aren't used in G0S0 */
317 resetNurseries( void )
323 /* All tasks must be stopped */
324 ASSERT(n_free_capabilities == RtsFlags.ParFlags.nNodes);
326 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
327 for (bd = cap->rNursery; bd; bd = bd->link) {
328 bd->free = bd->start;
329 ASSERT(bd->gen_no == 0);
330 ASSERT(bd->step == g0s0);
331 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
333 cap->rCurrentNursery = cap->rNursery;
336 for (bd = g0s0->blocks; bd; bd = bd->link) {
337 bd->free = bd->start;
338 ASSERT(bd->gen_no == 0);
339 ASSERT(bd->step == g0s0);
340 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
342 MainRegTable.rNursery = g0s0->blocks;
343 MainRegTable.rCurrentNursery = g0s0->blocks;
348 allocNursery (bdescr *last_bd, nat blocks)
353 /* Allocate a nursery */
354 for (i=0; i < blocks; i++) {
360 bd->free = bd->start;
367 resizeNursery ( nat blocks )
372 barf("resizeNursery: can't resize in SMP mode");
375 if (nursery_blocks == blocks) {
376 ASSERT(g0s0->n_blocks == blocks);
380 else if (nursery_blocks < blocks) {
381 IF_DEBUG(gc, fprintf(stderr, "Increasing size of nursery to %d blocks\n",
383 g0s0->blocks = allocNursery(g0s0->blocks, blocks-nursery_blocks);
389 IF_DEBUG(gc, fprintf(stderr, "Decreasing size of nursery to %d blocks\n",
391 for (bd = g0s0->blocks; nursery_blocks > blocks; nursery_blocks--) {
399 g0s0->n_blocks = nursery_blocks = blocks;
402 /* -----------------------------------------------------------------------------
403 The allocate() interface
405 allocate(n) always succeeds, and returns a chunk of memory n words
406 long. n can be larger than the size of a block if necessary, in
407 which case a contiguous block group will be allocated.
408 -------------------------------------------------------------------------- */
416 ACQUIRE_LOCK(&sm_mutex);
418 TICK_ALLOC_HEAP_NOCTR(n);
421 /* big allocation (>LARGE_OBJECT_THRESHOLD) */
422 /* ToDo: allocate directly into generation 1 */
423 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
424 nat req_blocks = (lnat)BLOCK_ROUND_UP(n*sizeof(W_)) / BLOCK_SIZE;
425 bd = allocGroup(req_blocks);
426 dbl_link_onto(bd, &g0s0->large_objects);
429 bd->flags = BF_LARGE;
430 bd->free = bd->start;
431 /* don't add these blocks to alloc_blocks, since we're assuming
432 * that large objects are likely to remain live for quite a while
433 * (eg. running threads), so garbage collecting early won't make
436 alloc_blocks += req_blocks;
437 RELEASE_LOCK(&sm_mutex);
440 /* small allocation (<LARGE_OBJECT_THRESHOLD) */
441 } else if (small_alloc_list == NULL || alloc_Hp + n > alloc_HpLim) {
442 if (small_alloc_list) {
443 small_alloc_list->free = alloc_Hp;
446 bd->link = small_alloc_list;
447 small_alloc_list = bd;
451 alloc_Hp = bd->start;
452 alloc_HpLim = bd->start + BLOCK_SIZE_W;
458 RELEASE_LOCK(&sm_mutex);
462 lnat allocated_bytes(void)
464 return (alloc_blocks * BLOCK_SIZE_W - (alloc_HpLim - alloc_Hp));
467 /* -----------------------------------------------------------------------------
468 Allocation functions for GMP.
470 These all use the allocate() interface - we can't have any garbage
471 collection going on during a gmp operation, so we use allocate()
472 which always succeeds. The gmp operations which might need to
473 allocate will ask the storage manager (via doYouWantToGC()) whether
474 a garbage collection is required, in case we get into a loop doing
475 only allocate() style allocation.
476 -------------------------------------------------------------------------- */
479 stgAllocForGMP (size_t size_in_bytes)
482 nat data_size_in_words, total_size_in_words;
484 /* should be a multiple of sizeof(StgWord) (whole no. of limbs) */
485 ASSERT(size_in_bytes % sizeof(W_) == 0);
487 data_size_in_words = size_in_bytes / sizeof(W_);
488 total_size_in_words = sizeofW(StgArrWords) + data_size_in_words;
490 /* allocate and fill it in. */
491 arr = (StgArrWords *)allocate(total_size_in_words);
492 SET_ARR_HDR(arr, &stg_ARR_WORDS_info, CCCS, data_size_in_words);
494 /* and return a ptr to the goods inside the array */
495 return(BYTE_ARR_CTS(arr));
499 stgReallocForGMP (void *ptr, size_t old_size, size_t new_size)
501 void *new_stuff_ptr = stgAllocForGMP(new_size);
503 char *p = (char *) ptr;
504 char *q = (char *) new_stuff_ptr;
506 for (; i < old_size; i++, p++, q++) {
510 return(new_stuff_ptr);
514 stgDeallocForGMP (void *ptr STG_UNUSED,
515 size_t size STG_UNUSED)
517 /* easy for us: the garbage collector does the dealloc'n */
520 /* -----------------------------------------------------------------------------
522 * -------------------------------------------------------------------------- */
524 /* -----------------------------------------------------------------------------
527 * Approximate how much we've allocated: number of blocks in the
528 * nursery + blocks allocated via allocate() - unused nusery blocks.
529 * This leaves a little slop at the end of each block, and doesn't
530 * take into account large objects (ToDo).
531 * -------------------------------------------------------------------------- */
534 calcAllocated( void )
542 /* All tasks must be stopped. Can't assert that all the
543 capabilities are owned by the scheduler, though: one or more
544 tasks might have been stopped while they were running (non-main)
546 /* ASSERT(n_free_capabilities == RtsFlags.ParFlags.nNodes); */
549 n_free_capabilities * RtsFlags.GcFlags.minAllocAreaSize * BLOCK_SIZE_W
552 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
553 for ( bd = cap->rCurrentNursery->link; bd != NULL; bd = bd->link ) {
554 allocated -= BLOCK_SIZE_W;
556 if (cap->rCurrentNursery->free < cap->rCurrentNursery->start
558 allocated -= (cap->rCurrentNursery->start + BLOCK_SIZE_W)
559 - cap->rCurrentNursery->free;
564 bdescr *current_nursery = MainRegTable.rCurrentNursery;
566 allocated = (nursery_blocks * BLOCK_SIZE_W) + allocated_bytes();
567 for ( bd = current_nursery->link; bd != NULL; bd = bd->link ) {
568 allocated -= BLOCK_SIZE_W;
570 if (current_nursery->free < current_nursery->start + BLOCK_SIZE_W) {
571 allocated -= (current_nursery->start + BLOCK_SIZE_W)
572 - current_nursery->free;
576 total_allocated += allocated;
580 /* Approximate the amount of live data in the heap. To be called just
581 * after garbage collection (see GarbageCollect()).
590 if (RtsFlags.GcFlags.generations == 1) {
591 live = (g0s0->n_to_blocks - 1) * BLOCK_SIZE_W +
592 ((lnat)g0s0->hp_bd->free - (lnat)g0s0->hp_bd->start) / sizeof(W_);
596 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
597 for (s = 0; s < generations[g].n_steps; s++) {
598 /* approximate amount of live data (doesn't take into account slop
599 * at end of each block).
601 if (g == 0 && s == 0) {
604 stp = &generations[g].steps[s];
605 live += (stp->n_large_blocks + stp->n_blocks - 1) * BLOCK_SIZE_W;
606 if (stp->hp_bd != NULL) {
607 live += ((lnat)stp->hp_bd->free - (lnat)stp->hp_bd->start)
615 /* Approximate the number of blocks that will be needed at the next
616 * garbage collection.
618 * Assume: all data currently live will remain live. Steps that will
619 * be collected next time will therefore need twice as many blocks
620 * since all the data will be copied.
629 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
630 for (s = 0; s < generations[g].n_steps; s++) {
631 if (g == 0 && s == 0) { continue; }
632 stp = &generations[g].steps[s];
633 if (generations[g].steps[0].n_blocks +
634 generations[g].steps[0].n_large_blocks
635 > generations[g].max_blocks
636 && stp->is_compacted == 0) {
637 needed += 2 * stp->n_blocks;
639 needed += stp->n_blocks;
646 /* -----------------------------------------------------------------------------
649 memInventory() checks for memory leaks by counting up all the
650 blocks we know about and comparing that to the number of blocks
651 allegedly floating around in the system.
652 -------------------------------------------------------------------------- */
662 lnat total_blocks = 0, free_blocks = 0;
664 /* count the blocks we current have */
666 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
667 for (s = 0; s < generations[g].n_steps; s++) {
668 stp = &generations[g].steps[s];
669 total_blocks += stp->n_blocks;
670 if (RtsFlags.GcFlags.generations == 1) {
671 /* two-space collector has a to-space too :-) */
672 total_blocks += g0s0->n_to_blocks;
674 for (bd = stp->large_objects; bd; bd = bd->link) {
675 total_blocks += bd->blocks;
676 /* hack for megablock groups: they have an extra block or two in
677 the second and subsequent megablocks where the block
678 descriptors would normally go.
680 if (bd->blocks > BLOCKS_PER_MBLOCK) {
681 total_blocks -= (MBLOCK_SIZE / BLOCK_SIZE - BLOCKS_PER_MBLOCK)
682 * (bd->blocks/(MBLOCK_SIZE/BLOCK_SIZE));
688 /* any blocks held by allocate() */
689 for (bd = small_alloc_list; bd; bd = bd->link) {
690 total_blocks += bd->blocks;
692 for (bd = large_alloc_list; bd; bd = bd->link) {
693 total_blocks += bd->blocks;
696 /* count the blocks on the free list */
697 free_blocks = countFreeList();
699 if (total_blocks + free_blocks != mblocks_allocated *
701 fprintf(stderr, "Blocks: %ld live + %ld free = %ld total (%ld around)\n",
702 total_blocks, free_blocks, total_blocks + free_blocks,
703 mblocks_allocated * BLOCKS_PER_MBLOCK);
706 ASSERT(total_blocks + free_blocks == mblocks_allocated * BLOCKS_PER_MBLOCK);
710 countBlocks(bdescr *bd)
713 for (n=0; bd != NULL; bd=bd->link) {
719 /* Full heap sanity check. */
725 if (RtsFlags.GcFlags.generations == 1) {
726 checkHeap(g0s0->to_blocks);
727 checkChain(g0s0->large_objects);
730 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
731 for (s = 0; s < generations[g].n_steps; s++) {
732 if (g == 0 && s == 0) { continue; }
733 checkHeap(generations[g].steps[s].blocks);
734 checkChain(generations[g].steps[s].large_objects);
735 ASSERT(countBlocks(generations[g].steps[s].blocks)
736 == generations[g].steps[s].n_blocks);
737 ASSERT(countBlocks(generations[g].steps[s].large_objects)
738 == generations[g].steps[s].n_large_blocks);
740 checkMutableList(generations[g].mut_list, g);
741 checkMutOnceList(generations[g].mut_once_list, g);
745 checkFreeListSanity();