1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.c,v 1.37 2001/03/22 03:51:10 hwloidl 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
71 #if defined(PROFILING) || defined(DEBUG)
72 if (RtsFlags.ProfFlags.doHeapProfile) {
73 RtsFlags.GcFlags.generations = 1;
74 RtsFlags.GcFlags.steps = 1;
75 RtsFlags.GcFlags.oldGenFactor = 0;
76 RtsFlags.GcFlags.heapSizeSuggestion = 0;
80 if (RtsFlags.GcFlags.heapSizeSuggestion >
81 RtsFlags.GcFlags.maxHeapSize) {
82 RtsFlags.GcFlags.maxHeapSize = RtsFlags.GcFlags.heapSizeSuggestion;
87 /* allocate generation info array */
88 generations = (generation *)stgMallocBytes(RtsFlags.GcFlags.generations
89 * sizeof(struct _generation),
92 /* Initialise all generations */
93 for(g = 0; g < RtsFlags.GcFlags.generations; g++) {
94 gen = &generations[g];
96 gen->mut_list = END_MUT_LIST;
97 gen->mut_once_list = END_MUT_LIST;
99 gen->failed_promotions = 0;
103 /* A couple of convenience pointers */
104 g0 = &generations[0];
105 oldest_gen = &generations[RtsFlags.GcFlags.generations-1];
107 /* Allocate step structures in each generation */
108 if (RtsFlags.GcFlags.generations > 1) {
109 /* Only for multiple-generations */
111 /* Oldest generation: one step */
112 oldest_gen->n_steps = 1;
114 stgMallocBytes(1 * sizeof(struct _step), "initStorage: last step");
116 /* set up all except the oldest generation with 2 steps */
117 for(g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
118 generations[g].n_steps = RtsFlags.GcFlags.steps;
119 generations[g].steps =
120 stgMallocBytes (RtsFlags.GcFlags.steps * sizeof(struct _step),
121 "initStorage: steps");
125 /* single generation, i.e. a two-space collector */
127 g0->steps = stgMallocBytes (sizeof(struct _step), "initStorage: steps");
130 /* Initialise all steps */
131 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
132 for (s = 0; s < generations[g].n_steps; s++) {
133 stp = &generations[g].steps[s];
137 stp->gen = &generations[g];
143 stp->large_objects = NULL;
144 stp->new_large_objects = NULL;
145 stp->scavenged_large_objects = NULL;
149 /* Set up the destination pointers in each younger gen. step */
150 for (g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
151 for (s = 0; s < generations[g].n_steps-1; s++) {
152 generations[g].steps[s].to = &generations[g].steps[s+1];
154 generations[g].steps[s].to = &generations[g+1].steps[0];
157 /* The oldest generation has one step and its destination is the
159 oldest_gen->steps[0].to = &oldest_gen->steps[0];
161 /* generation 0 is special: that's the nursery */
162 generations[0].max_blocks = 0;
164 /* G0S0: the allocation area. Policy: keep the allocation area
165 * small to begin with, even if we have a large suggested heap
166 * size. Reason: we're going to do a major collection first, and we
167 * don't want it to be a big one. This vague idea is borne out by
168 * rigorous experimental evidence.
170 g0s0 = &generations[0].steps[0];
174 weak_ptr_list = NULL;
177 /* initialise the allocate() interface */
178 small_alloc_list = NULL;
179 large_alloc_list = NULL;
181 alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
183 /* Tell GNU multi-precision pkg about our custom alloc functions */
184 mp_set_memory_functions(stgAllocForGMP, stgReallocForGMP, stgDeallocForGMP);
187 pthread_mutex_init(&sm_mutex, NULL);
190 IF_DEBUG(gc, stat_describe_gens());
196 stat_exit(calcAllocated());
199 /* -----------------------------------------------------------------------------
202 The entry code for every CAF does the following:
204 - builds a CAF_BLACKHOLE in the heap
205 - pushes an update frame pointing to the CAF_BLACKHOLE
206 - invokes UPD_CAF(), which:
207 - calls newCaf, below
208 - updates the CAF with a static indirection to the CAF_BLACKHOLE
210 Why do we build a BLACKHOLE in the heap rather than just updating
211 the thunk directly? It's so that we only need one kind of update
212 frame - otherwise we'd need a static version of the update frame too.
214 newCaf() does the following:
216 - it puts the CAF on the oldest generation's mut-once list.
217 This is so that we can treat the CAF as a root when collecting
220 For GHCI, we have additional requirements when dealing with CAFs:
222 - we must *retain* all dynamically-loaded CAFs ever entered,
223 just in case we need them again.
224 - we must be able to *revert* CAFs that have been evaluated, to
225 their pre-evaluated form.
227 To do this, we use an additional CAF list. When newCaf() is
228 called on a dynamically-loaded CAF, we add it to the CAF list
229 instead of the old-generation mutable list, and save away its
230 old info pointer (in caf->saved_info) for later reversion.
232 To revert all the CAFs, we traverse the CAF list and reset the
233 info pointer to caf->saved_info, then throw away the CAF list.
234 (see GC.c:revertCAFs()).
238 -------------------------------------------------------------------------- */
241 newCAF(StgClosure* caf)
243 /* Put this CAF on the mutable list for the old generation.
244 * This is a HACK - the IND_STATIC closure doesn't really have
245 * a mut_link field, but we pretend it has - in fact we re-use
246 * the STATIC_LINK field for the time being, because when we
247 * come to do a major GC we won't need the mut_link field
248 * any more and can use it as a STATIC_LINK.
250 ACQUIRE_LOCK(&sm_mutex);
252 if (is_dynamically_loaded_rwdata_ptr((StgPtr)caf)) {
253 ((StgIndStatic *)caf)->saved_info = (StgInfoTable *)caf->header.info;
254 ((StgIndStatic *)caf)->static_link = caf_list;
257 ((StgIndStatic *)caf)->saved_info = NULL;
258 ((StgMutClosure *)caf)->mut_link = oldest_gen->mut_once_list;
259 oldest_gen->mut_once_list = (StgMutClosure *)caf;
262 RELEASE_LOCK(&sm_mutex);
265 /* If we are PAR or DIST then we never forget a CAF */
267 //belch("<##> Globalising CAF %08x %s",caf,info_type(caf));
268 newGA=makeGlobal(caf,rtsTrue); /*given full weight*/
274 /* -----------------------------------------------------------------------------
276 -------------------------------------------------------------------------- */
279 allocNurseries( void )
288 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
289 cap->rNursery = allocNursery(NULL, RtsFlags.GcFlags.minAllocAreaSize);
290 cap->rCurrentNursery = cap->rNursery;
291 for (bd = cap->rNursery; bd != NULL; bd = bd->link) {
292 bd->back = (bdescr *)cap;
295 /* Set the back links to be equal to the Capability,
296 * so we can do slightly better informed locking.
300 nursery_blocks = RtsFlags.GcFlags.minAllocAreaSize;
301 g0s0->blocks = allocNursery(NULL, nursery_blocks);
302 g0s0->n_blocks = nursery_blocks;
303 g0s0->to_space = NULL;
304 MainRegTable.rNursery = g0s0->blocks;
305 MainRegTable.rCurrentNursery = g0s0->blocks;
306 /* hp, hpLim, hp_bd, to_space etc. aren't used in G0S0 */
311 resetNurseries( void )
317 /* All tasks must be stopped */
318 ASSERT(n_free_capabilities == RtsFlags.ParFlags.nNodes);
320 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
321 for (bd = cap->rNursery; bd; bd = bd->link) {
322 bd->free = bd->start;
323 ASSERT(bd->gen == g0);
324 ASSERT(bd->step == g0s0);
325 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
327 cap->rCurrentNursery = cap->rNursery;
330 for (bd = g0s0->blocks; bd; bd = bd->link) {
331 bd->free = bd->start;
332 ASSERT(bd->gen == g0);
333 ASSERT(bd->step == g0s0);
334 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
336 MainRegTable.rNursery = g0s0->blocks;
337 MainRegTable.rCurrentNursery = g0s0->blocks;
342 allocNursery (bdescr *last_bd, nat blocks)
347 /* Allocate a nursery */
348 for (i=0; i < blocks; i++) {
354 bd->free = bd->start;
361 resizeNursery ( nat blocks )
366 barf("resizeNursery: can't resize in SMP mode");
369 if (nursery_blocks == blocks) {
370 ASSERT(g0s0->n_blocks == blocks);
374 else if (nursery_blocks < blocks) {
375 IF_DEBUG(gc, fprintf(stderr, "Increasing size of nursery to %d blocks\n",
377 g0s0->blocks = allocNursery(g0s0->blocks, blocks-nursery_blocks);
383 IF_DEBUG(gc, fprintf(stderr, "Decreasing size of nursery to %d blocks\n",
385 for (bd = g0s0->blocks; nursery_blocks > blocks; nursery_blocks--) {
393 g0s0->n_blocks = nursery_blocks = blocks;
396 /* -----------------------------------------------------------------------------
397 The allocate() interface
399 allocate(n) always succeeds, and returns a chunk of memory n words
400 long. n can be larger than the size of a block if necessary, in
401 which case a contiguous block group will be allocated.
402 -------------------------------------------------------------------------- */
410 ACQUIRE_LOCK(&sm_mutex);
412 TICK_ALLOC_HEAP_NOCTR(n);
415 /* big allocation (>LARGE_OBJECT_THRESHOLD) */
416 /* ToDo: allocate directly into generation 1 */
417 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
418 nat req_blocks = (lnat)BLOCK_ROUND_UP(n*sizeof(W_)) / BLOCK_SIZE;
419 bd = allocGroup(req_blocks);
420 dbl_link_onto(bd, &g0s0->large_objects);
424 bd->free = bd->start;
425 /* don't add these blocks to alloc_blocks, since we're assuming
426 * that large objects are likely to remain live for quite a while
427 * (eg. running threads), so garbage collecting early won't make
430 alloc_blocks += req_blocks;
431 RELEASE_LOCK(&sm_mutex);
434 /* small allocation (<LARGE_OBJECT_THRESHOLD) */
435 } else if (small_alloc_list == NULL || alloc_Hp + n > alloc_HpLim) {
436 if (small_alloc_list) {
437 small_alloc_list->free = alloc_Hp;
440 bd->link = small_alloc_list;
441 small_alloc_list = bd;
445 alloc_Hp = bd->start;
446 alloc_HpLim = bd->start + BLOCK_SIZE_W;
452 RELEASE_LOCK(&sm_mutex);
456 lnat allocated_bytes(void)
458 return (alloc_blocks * BLOCK_SIZE_W - (alloc_HpLim - alloc_Hp));
461 /* -----------------------------------------------------------------------------
462 Allocation functions for GMP.
464 These all use the allocate() interface - we can't have any garbage
465 collection going on during a gmp operation, so we use allocate()
466 which always succeeds. The gmp operations which might need to
467 allocate will ask the storage manager (via doYouWantToGC()) whether
468 a garbage collection is required, in case we get into a loop doing
469 only allocate() style allocation.
470 -------------------------------------------------------------------------- */
473 stgAllocForGMP (size_t size_in_bytes)
476 nat data_size_in_words, total_size_in_words;
478 /* should be a multiple of sizeof(StgWord) (whole no. of limbs) */
479 ASSERT(size_in_bytes % sizeof(W_) == 0);
481 data_size_in_words = size_in_bytes / sizeof(W_);
482 total_size_in_words = sizeofW(StgArrWords) + data_size_in_words;
484 /* allocate and fill it in. */
485 arr = (StgArrWords *)allocate(total_size_in_words);
486 SET_ARR_HDR(arr, &stg_ARR_WORDS_info, CCCS, data_size_in_words);
488 /* and return a ptr to the goods inside the array */
489 return(BYTE_ARR_CTS(arr));
493 stgReallocForGMP (void *ptr, size_t old_size, size_t new_size)
495 void *new_stuff_ptr = stgAllocForGMP(new_size);
497 char *p = (char *) ptr;
498 char *q = (char *) new_stuff_ptr;
500 for (; i < old_size; i++, p++, q++) {
504 return(new_stuff_ptr);
508 stgDeallocForGMP (void *ptr STG_UNUSED,
509 size_t size STG_UNUSED)
511 /* easy for us: the garbage collector does the dealloc'n */
514 /* -----------------------------------------------------------------------------
516 * -------------------------------------------------------------------------- */
518 /* -----------------------------------------------------------------------------
521 * Approximate how much we've allocated: number of blocks in the
522 * nursery + blocks allocated via allocate() - unused nusery blocks.
523 * This leaves a little slop at the end of each block, and doesn't
524 * take into account large objects (ToDo).
525 * -------------------------------------------------------------------------- */
528 calcAllocated( void )
536 /* All tasks must be stopped. Can't assert that all the
537 capabilities are owned by the scheduler, though: one or more
538 tasks might have been stopped while they were running (non-main)
540 /* ASSERT(n_free_capabilities == RtsFlags.ParFlags.nNodes); */
543 n_free_capabilities * RtsFlags.GcFlags.minAllocAreaSize * BLOCK_SIZE_W
546 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
547 for ( bd = cap->rCurrentNursery->link; bd != NULL; bd = bd->link ) {
548 allocated -= BLOCK_SIZE_W;
550 if (cap->rCurrentNursery->free < cap->rCurrentNursery->start
552 allocated -= (cap->rCurrentNursery->start + BLOCK_SIZE_W)
553 - cap->rCurrentNursery->free;
558 bdescr *current_nursery = MainRegTable.rCurrentNursery;
560 allocated = (nursery_blocks * BLOCK_SIZE_W) + allocated_bytes();
561 for ( bd = current_nursery->link; bd != NULL; bd = bd->link ) {
562 allocated -= BLOCK_SIZE_W;
564 if (current_nursery->free < current_nursery->start + BLOCK_SIZE_W) {
565 allocated -= (current_nursery->start + BLOCK_SIZE_W)
566 - current_nursery->free;
570 total_allocated += allocated;
574 /* Approximate the amount of live data in the heap. To be called just
575 * after garbage collection (see GarbageCollect()).
584 if (RtsFlags.GcFlags.generations == 1) {
585 live = (g0s0->to_blocks - 1) * BLOCK_SIZE_W +
586 ((lnat)g0s0->hp_bd->free - (lnat)g0s0->hp_bd->start) / sizeof(W_);
590 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
591 for (s = 0; s < generations[g].n_steps; s++) {
592 /* approximate amount of live data (doesn't take into account slop
593 * at end of each block).
595 if (g == 0 && s == 0) {
598 stp = &generations[g].steps[s];
599 live += (stp->n_blocks - 1) * BLOCK_SIZE_W +
600 ((lnat)stp->hp_bd->free - (lnat)stp->hp_bd->start) / sizeof(W_);
606 /* Approximate the number of blocks that will be needed at the next
607 * garbage collection.
609 * Assume: all data currently live will remain live. Steps that will
610 * be collected next time will therefore need twice as many blocks
611 * since all the data will be copied.
620 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
621 for (s = 0; s < generations[g].n_steps; s++) {
622 if (g == 0 && s == 0) { continue; }
623 stp = &generations[g].steps[s];
624 if (generations[g].steps[0].n_blocks > generations[g].max_blocks) {
625 needed += 2 * stp->n_blocks;
627 needed += stp->n_blocks;
634 /* -----------------------------------------------------------------------------
637 memInventory() checks for memory leaks by counting up all the
638 blocks we know about and comparing that to the number of blocks
639 allegedly floating around in the system.
640 -------------------------------------------------------------------------- */
650 lnat total_blocks = 0, free_blocks = 0;
652 /* count the blocks we current have */
654 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
655 for (s = 0; s < generations[g].n_steps; s++) {
656 stp = &generations[g].steps[s];
657 total_blocks += stp->n_blocks;
658 if (RtsFlags.GcFlags.generations == 1) {
659 /* two-space collector has a to-space too :-) */
660 total_blocks += g0s0->to_blocks;
662 for (bd = stp->large_objects; bd; bd = bd->link) {
663 total_blocks += bd->blocks;
664 /* hack for megablock groups: they have an extra block or two in
665 the second and subsequent megablocks where the block
666 descriptors would normally go.
668 if (bd->blocks > BLOCKS_PER_MBLOCK) {
669 total_blocks -= (MBLOCK_SIZE / BLOCK_SIZE - BLOCKS_PER_MBLOCK)
670 * (bd->blocks/(MBLOCK_SIZE/BLOCK_SIZE));
676 /* any blocks held by allocate() */
677 for (bd = small_alloc_list; bd; bd = bd->link) {
678 total_blocks += bd->blocks;
680 for (bd = large_alloc_list; bd; bd = bd->link) {
681 total_blocks += bd->blocks;
684 /* count the blocks on the free list */
685 free_blocks = countFreeList();
687 ASSERT(total_blocks + free_blocks == mblocks_allocated * BLOCKS_PER_MBLOCK);
690 if (total_blocks + free_blocks != mblocks_allocated *
692 fprintf(stderr, "Blocks: %ld live + %ld free = %ld total (%ld around)\n",
693 total_blocks, free_blocks, total_blocks + free_blocks,
694 mblocks_allocated * BLOCKS_PER_MBLOCK);
699 /* Full heap sanity check. */
706 if (RtsFlags.GcFlags.generations == 1) {
707 checkHeap(g0s0->to_space, NULL);
708 checkChain(g0s0->large_objects);
711 for (g = 0; g <= N; g++) {
712 for (s = 0; s < generations[g].n_steps; s++) {
713 if (g == 0 && s == 0) { continue; }
714 checkHeap(generations[g].steps[s].blocks, NULL);
717 for (g = N+1; g < RtsFlags.GcFlags.generations; g++) {
718 for (s = 0; s < generations[g].n_steps; s++) {
719 checkHeap(generations[g].steps[s].blocks,
720 generations[g].steps[s].blocks->start);
721 checkChain(generations[g].steps[s].large_objects);
724 checkFreeListSanity();