1 /* -----------------------------------------------------------------------------
2 * $Id: Storage.c,v 1.72 2002/12/13 19:17:02 wolfgang Exp $
4 * (c) The GHC Team, 1998-1999
6 * Storage manager front end
8 * ---------------------------------------------------------------------------*/
10 #include "PosixSource.h"
16 #include "BlockAlloc.h"
24 #include "OSThreads.h"
25 #include "StoragePriv.h"
27 #include "RetainerProfile.h" // for counting memory blocks (memInventory)
32 StgClosure *caf_list = NULL;
34 bdescr *small_alloc_list; /* allocate()d small objects */
35 bdescr *pinned_object_block; /* allocate pinned objects into this block */
36 nat alloc_blocks; /* number of allocate()d blocks since GC */
37 nat alloc_blocks_lim; /* approximate limit on alloc_blocks */
39 StgPtr alloc_Hp = NULL; /* next free byte in small_alloc_list */
40 StgPtr alloc_HpLim = NULL; /* end of block at small_alloc_list */
42 generation *generations; /* all the generations */
43 generation *g0; /* generation 0, for convenience */
44 generation *oldest_gen; /* oldest generation, for convenience */
45 step *g0s0; /* generation 0, step 0, for convenience */
47 lnat total_allocated = 0; /* total memory allocated during run */
50 * Storage manager mutex: protects all the above state from
51 * simultaneous access by two STG threads.
54 Mutex sm_mutex = INIT_MUTEX_VAR;
60 static void *stgAllocForGMP (size_t size_in_bytes);
61 static void *stgReallocForGMP (void *ptr, size_t old_size, size_t new_size);
62 static void stgDeallocForGMP (void *ptr, size_t size);
71 /* Sanity check to make sure the LOOKS_LIKE_ macros appear to be
72 * doing something reasonable.
74 ASSERT(LOOKS_LIKE_INFO_PTR(&stg_BLACKHOLE_info));
75 ASSERT(LOOKS_LIKE_CLOSURE_PTR(&stg_dummy_ret_closure));
76 ASSERT(!HEAP_ALLOCED(&stg_dummy_ret_closure));
78 if (RtsFlags.GcFlags.maxHeapSize != 0 &&
79 RtsFlags.GcFlags.heapSizeSuggestion >
80 RtsFlags.GcFlags.maxHeapSize) {
81 RtsFlags.GcFlags.maxHeapSize = RtsFlags.GcFlags.heapSizeSuggestion;
84 if (RtsFlags.GcFlags.maxHeapSize != 0 &&
85 RtsFlags.GcFlags.minAllocAreaSize >
86 RtsFlags.GcFlags.maxHeapSize) {
87 prog_belch("maximum heap size (-M) is smaller than minimum alloc area size (-A)");
94 initCondition(&sm_mutex);
97 /* allocate generation info array */
98 generations = (generation *)stgMallocBytes(RtsFlags.GcFlags.generations
99 * sizeof(struct _generation),
100 "initStorage: gens");
102 /* Initialise all generations */
103 for(g = 0; g < RtsFlags.GcFlags.generations; g++) {
104 gen = &generations[g];
106 gen->mut_list = END_MUT_LIST;
107 gen->mut_once_list = END_MUT_LIST;
108 gen->collections = 0;
109 gen->failed_promotions = 0;
113 /* A couple of convenience pointers */
114 g0 = &generations[0];
115 oldest_gen = &generations[RtsFlags.GcFlags.generations-1];
117 /* Allocate step structures in each generation */
118 if (RtsFlags.GcFlags.generations > 1) {
119 /* Only for multiple-generations */
121 /* Oldest generation: one step */
122 oldest_gen->n_steps = 1;
124 stgMallocBytes(1 * sizeof(struct _step), "initStorage: last step");
126 /* set up all except the oldest generation with 2 steps */
127 for(g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
128 generations[g].n_steps = RtsFlags.GcFlags.steps;
129 generations[g].steps =
130 stgMallocBytes (RtsFlags.GcFlags.steps * sizeof(struct _step),
131 "initStorage: steps");
135 /* single generation, i.e. a two-space collector */
137 g0->steps = stgMallocBytes (sizeof(struct _step), "initStorage: steps");
140 /* Initialise all steps */
141 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
142 for (s = 0; s < generations[g].n_steps; s++) {
143 stp = &generations[g].steps[s];
147 stp->gen = &generations[g];
154 stp->large_objects = NULL;
155 stp->n_large_blocks = 0;
156 stp->new_large_objects = NULL;
157 stp->scavenged_large_objects = NULL;
158 stp->n_scavenged_large_blocks = 0;
159 stp->is_compacted = 0;
164 /* Set up the destination pointers in each younger gen. step */
165 for (g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
166 for (s = 0; s < generations[g].n_steps-1; s++) {
167 generations[g].steps[s].to = &generations[g].steps[s+1];
169 generations[g].steps[s].to = &generations[g+1].steps[0];
172 /* The oldest generation has one step and it is compacted. */
173 if (RtsFlags.GcFlags.compact) {
174 if (RtsFlags.GcFlags.generations == 1) {
175 belch("WARNING: compaction is incompatible with -G1; disabled");
177 oldest_gen->steps[0].is_compacted = 1;
180 oldest_gen->steps[0].to = &oldest_gen->steps[0];
182 /* generation 0 is special: that's the nursery */
183 generations[0].max_blocks = 0;
185 /* G0S0: the allocation area. Policy: keep the allocation area
186 * small to begin with, even if we have a large suggested heap
187 * size. Reason: we're going to do a major collection first, and we
188 * don't want it to be a big one. This vague idea is borne out by
189 * rigorous experimental evidence.
191 g0s0 = &generations[0].steps[0];
195 weak_ptr_list = NULL;
198 /* initialise the allocate() interface */
199 small_alloc_list = NULL;
201 alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
203 /* Tell GNU multi-precision pkg about our custom alloc functions */
204 mp_set_memory_functions(stgAllocForGMP, stgReallocForGMP, stgDeallocForGMP);
207 initMutex(&sm_mutex);
210 IF_DEBUG(gc, statDescribeGens());
216 stat_exit(calcAllocated());
219 /* -----------------------------------------------------------------------------
222 The entry code for every CAF does the following:
224 - builds a CAF_BLACKHOLE in the heap
225 - pushes an update frame pointing to the CAF_BLACKHOLE
226 - invokes UPD_CAF(), which:
227 - calls newCaf, below
228 - updates the CAF with a static indirection to the CAF_BLACKHOLE
230 Why do we build a BLACKHOLE in the heap rather than just updating
231 the thunk directly? It's so that we only need one kind of update
232 frame - otherwise we'd need a static version of the update frame too.
234 newCaf() does the following:
236 - it puts the CAF on the oldest generation's mut-once list.
237 This is so that we can treat the CAF as a root when collecting
240 For GHCI, we have additional requirements when dealing with CAFs:
242 - we must *retain* all dynamically-loaded CAFs ever entered,
243 just in case we need them again.
244 - we must be able to *revert* CAFs that have been evaluated, to
245 their pre-evaluated form.
247 To do this, we use an additional CAF list. When newCaf() is
248 called on a dynamically-loaded CAF, we add it to the CAF list
249 instead of the old-generation mutable list, and save away its
250 old info pointer (in caf->saved_info) for later reversion.
252 To revert all the CAFs, we traverse the CAF list and reset the
253 info pointer to caf->saved_info, then throw away the CAF list.
254 (see GC.c:revertCAFs()).
258 -------------------------------------------------------------------------- */
261 newCAF(StgClosure* caf)
263 /* Put this CAF on the mutable list for the old generation.
264 * This is a HACK - the IND_STATIC closure doesn't really have
265 * a mut_link field, but we pretend it has - in fact we re-use
266 * the STATIC_LINK field for the time being, because when we
267 * come to do a major GC we won't need the mut_link field
268 * any more and can use it as a STATIC_LINK.
272 if (0 /*TODO: is_dynamically_loaded_rwdata_ptr((StgPtr)caf)*/) {
273 ((StgIndStatic *)caf)->saved_info = (StgInfoTable *)caf->header.info;
274 ((StgIndStatic *)caf)->static_link = caf_list;
277 ((StgIndStatic *)caf)->saved_info = NULL;
278 ((StgMutClosure *)caf)->mut_link = oldest_gen->mut_once_list;
279 oldest_gen->mut_once_list = (StgMutClosure *)caf;
285 /* If we are PAR or DIST then we never forget a CAF */
287 //belch("<##> Globalising CAF %08x %s",caf,info_type(caf));
288 newGA=makeGlobal(caf,rtsTrue); /*given full weight*/
294 /* -----------------------------------------------------------------------------
296 -------------------------------------------------------------------------- */
299 allocNurseries( void )
308 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
309 cap->r.rNursery = allocNursery(NULL, RtsFlags.GcFlags.minAllocAreaSize);
310 cap->r.rCurrentNursery = cap->r.rNursery;
311 for (bd = cap->r.rNursery; bd != NULL; bd = bd->link) {
312 bd->u.back = (bdescr *)cap;
315 /* Set the back links to be equal to the Capability,
316 * so we can do slightly better informed locking.
320 g0s0->blocks = allocNursery(NULL, RtsFlags.GcFlags.minAllocAreaSize);
321 g0s0->n_blocks = RtsFlags.GcFlags.minAllocAreaSize;
322 g0s0->to_blocks = NULL;
323 g0s0->n_to_blocks = 0;
324 MainCapability.r.rNursery = g0s0->blocks;
325 MainCapability.r.rCurrentNursery = g0s0->blocks;
326 /* hp, hpLim, hp_bd, to_space etc. aren't used in G0S0 */
331 resetNurseries( void )
337 /* All tasks must be stopped */
338 ASSERT(n_free_capabilities == RtsFlags.ParFlags.nNodes);
340 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
341 for (bd = cap->r.rNursery; bd; bd = bd->link) {
342 bd->free = bd->start;
343 ASSERT(bd->gen_no == 0);
344 ASSERT(bd->step == g0s0);
345 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
347 cap->r.rCurrentNursery = cap->r.rNursery;
350 for (bd = g0s0->blocks; bd; bd = bd->link) {
351 bd->free = bd->start;
352 ASSERT(bd->gen_no == 0);
353 ASSERT(bd->step == g0s0);
354 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
356 MainCapability.r.rNursery = g0s0->blocks;
357 MainCapability.r.rCurrentNursery = g0s0->blocks;
362 allocNursery (bdescr *tail, nat blocks)
367 // Allocate a nursery: we allocate fresh blocks one at a time and
368 // cons them on to the front of the list, not forgetting to update
369 // the back pointer on the tail of the list to point to the new block.
370 for (i=0; i < blocks; i++) {
373 processNursery() in LdvProfile.c assumes that every block group in
374 the nursery contains only a single block. So, if a block group is
375 given multiple blocks, change processNursery() accordingly.
379 // double-link the nursery: we might need to insert blocks
386 bd->free = bd->start;
394 resizeNursery ( nat blocks )
400 barf("resizeNursery: can't resize in SMP mode");
403 nursery_blocks = g0s0->n_blocks;
404 if (nursery_blocks == blocks) {
408 else if (nursery_blocks < blocks) {
409 IF_DEBUG(gc, fprintf(stderr, "Increasing size of nursery to %d blocks\n",
411 g0s0->blocks = allocNursery(g0s0->blocks, blocks-nursery_blocks);
417 IF_DEBUG(gc, fprintf(stderr, "Decreasing size of nursery to %d blocks\n",
421 while (nursery_blocks > blocks) {
423 next_bd->u.back = NULL;
424 nursery_blocks -= bd->blocks; // might be a large block
429 // might have gone just under, by freeing a large block, so make
430 // up the difference.
431 if (nursery_blocks < blocks) {
432 g0s0->blocks = allocNursery(g0s0->blocks, blocks-nursery_blocks);
436 g0s0->n_blocks = blocks;
437 ASSERT(countBlocks(g0s0->blocks) == g0s0->n_blocks);
440 /* -----------------------------------------------------------------------------
441 The allocate() interface
443 allocate(n) always succeeds, and returns a chunk of memory n words
444 long. n can be larger than the size of a block if necessary, in
445 which case a contiguous block group will be allocated.
446 -------------------------------------------------------------------------- */
456 TICK_ALLOC_HEAP_NOCTR(n);
459 /* big allocation (>LARGE_OBJECT_THRESHOLD) */
460 /* ToDo: allocate directly into generation 1 */
461 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
462 nat req_blocks = (lnat)BLOCK_ROUND_UP(n*sizeof(W_)) / BLOCK_SIZE;
463 bd = allocGroup(req_blocks);
464 dbl_link_onto(bd, &g0s0->large_objects);
467 bd->flags = BF_LARGE;
468 bd->free = bd->start;
469 /* don't add these blocks to alloc_blocks, since we're assuming
470 * that large objects are likely to remain live for quite a while
471 * (eg. running threads), so garbage collecting early won't make
474 alloc_blocks += req_blocks;
478 /* small allocation (<LARGE_OBJECT_THRESHOLD) */
479 } else if (small_alloc_list == NULL || alloc_Hp + n > alloc_HpLim) {
480 if (small_alloc_list) {
481 small_alloc_list->free = alloc_Hp;
484 bd->link = small_alloc_list;
485 small_alloc_list = bd;
489 alloc_Hp = bd->start;
490 alloc_HpLim = bd->start + BLOCK_SIZE_W;
501 allocated_bytes( void )
505 allocated = alloc_blocks * BLOCK_SIZE_W - (alloc_HpLim - alloc_Hp);
506 if (pinned_object_block != NULL) {
507 allocated -= (pinned_object_block->start + BLOCK_SIZE_W) -
508 pinned_object_block->free;
515 tidyAllocateLists (void)
517 if (small_alloc_list != NULL) {
518 ASSERT(alloc_Hp >= small_alloc_list->start &&
519 alloc_Hp <= small_alloc_list->start + BLOCK_SIZE);
520 small_alloc_list->free = alloc_Hp;
524 /* ---------------------------------------------------------------------------
525 Allocate a fixed/pinned object.
527 We allocate small pinned objects into a single block, allocating a
528 new block when the current one overflows. The block is chained
529 onto the large_object_list of generation 0 step 0.
531 NOTE: The GC can't in general handle pinned objects. This
532 interface is only safe to use for ByteArrays, which have no
533 pointers and don't require scavenging. It works because the
534 block's descriptor has the BF_LARGE flag set, so the block is
535 treated as a large object and chained onto various lists, rather
536 than the individual objects being copied. However, when it comes
537 to scavenge the block, the GC will only scavenge the first object.
538 The reason is that the GC can't linearly scan a block of pinned
539 objects at the moment (doing so would require using the
540 mostly-copying techniques). But since we're restricting ourselves
541 to pinned ByteArrays, not scavenging is ok.
543 This function is called by newPinnedByteArray# which immediately
544 fills the allocated memory with a MutableByteArray#.
545 ------------------------------------------------------------------------- */
548 allocatePinned( nat n )
551 bdescr *bd = pinned_object_block;
555 TICK_ALLOC_HEAP_NOCTR(n);
558 // If the request is for a large object, then allocate()
559 // will give us a pinned object anyway.
560 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
565 // we always return 8-byte aligned memory. bd->free must be
566 // 8-byte aligned to begin with, so we just round up n to
567 // the nearest multiple of 8 bytes.
568 if (sizeof(StgWord) == 4) {
572 // If we don't have a block of pinned objects yet, or the current
573 // one isn't large enough to hold the new object, allocate a new one.
574 if (bd == NULL || (bd->free + n) > (bd->start + BLOCK_SIZE_W)) {
575 pinned_object_block = bd = allocBlock();
576 dbl_link_onto(bd, &g0s0->large_objects);
579 bd->flags = BF_LARGE;
580 bd->free = bd->start;
590 /* -----------------------------------------------------------------------------
591 Allocation functions for GMP.
593 These all use the allocate() interface - we can't have any garbage
594 collection going on during a gmp operation, so we use allocate()
595 which always succeeds. The gmp operations which might need to
596 allocate will ask the storage manager (via doYouWantToGC()) whether
597 a garbage collection is required, in case we get into a loop doing
598 only allocate() style allocation.
599 -------------------------------------------------------------------------- */
602 stgAllocForGMP (size_t size_in_bytes)
605 nat data_size_in_words, total_size_in_words;
607 /* round up to a whole number of words */
608 data_size_in_words = (size_in_bytes + sizeof(W_) + 1) / sizeof(W_);
609 total_size_in_words = sizeofW(StgArrWords) + data_size_in_words;
611 /* allocate and fill it in. */
612 arr = (StgArrWords *)allocate(total_size_in_words);
613 SET_ARR_HDR(arr, &stg_ARR_WORDS_info, CCCS, data_size_in_words);
615 /* and return a ptr to the goods inside the array */
616 return(BYTE_ARR_CTS(arr));
620 stgReallocForGMP (void *ptr, size_t old_size, size_t new_size)
622 void *new_stuff_ptr = stgAllocForGMP(new_size);
624 char *p = (char *) ptr;
625 char *q = (char *) new_stuff_ptr;
627 for (; i < old_size; i++, p++, q++) {
631 return(new_stuff_ptr);
635 stgDeallocForGMP (void *ptr STG_UNUSED,
636 size_t size STG_UNUSED)
638 /* easy for us: the garbage collector does the dealloc'n */
641 /* -----------------------------------------------------------------------------
643 * -------------------------------------------------------------------------- */
645 /* -----------------------------------------------------------------------------
648 * Approximate how much we've allocated: number of blocks in the
649 * nursery + blocks allocated via allocate() - unused nusery blocks.
650 * This leaves a little slop at the end of each block, and doesn't
651 * take into account large objects (ToDo).
652 * -------------------------------------------------------------------------- */
655 calcAllocated( void )
663 /* All tasks must be stopped. Can't assert that all the
664 capabilities are owned by the scheduler, though: one or more
665 tasks might have been stopped while they were running (non-main)
667 /* ASSERT(n_free_capabilities == RtsFlags.ParFlags.nNodes); */
670 n_free_capabilities * RtsFlags.GcFlags.minAllocAreaSize * BLOCK_SIZE_W
673 for (cap = free_capabilities; cap != NULL; cap = cap->link) {
674 for ( bd = cap->r.rCurrentNursery->link; bd != NULL; bd = bd->link ) {
675 allocated -= BLOCK_SIZE_W;
677 if (cap->r.rCurrentNursery->free < cap->r.rCurrentNursery->start
679 allocated -= (cap->r.rCurrentNursery->start + BLOCK_SIZE_W)
680 - cap->r.rCurrentNursery->free;
685 bdescr *current_nursery = MainCapability.r.rCurrentNursery;
687 allocated = (g0s0->n_blocks * BLOCK_SIZE_W) + allocated_bytes();
688 for ( bd = current_nursery->link; bd != NULL; bd = bd->link ) {
689 allocated -= BLOCK_SIZE_W;
691 if (current_nursery->free < current_nursery->start + BLOCK_SIZE_W) {
692 allocated -= (current_nursery->start + BLOCK_SIZE_W)
693 - current_nursery->free;
697 total_allocated += allocated;
701 /* Approximate the amount of live data in the heap. To be called just
702 * after garbage collection (see GarbageCollect()).
711 if (RtsFlags.GcFlags.generations == 1) {
712 live = (g0s0->n_to_blocks - 1) * BLOCK_SIZE_W +
713 ((lnat)g0s0->hp_bd->free - (lnat)g0s0->hp_bd->start) / sizeof(W_);
717 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
718 for (s = 0; s < generations[g].n_steps; s++) {
719 /* approximate amount of live data (doesn't take into account slop
720 * at end of each block).
722 if (g == 0 && s == 0) {
725 stp = &generations[g].steps[s];
726 live += (stp->n_large_blocks + stp->n_blocks - 1) * BLOCK_SIZE_W;
727 if (stp->hp_bd != NULL) {
728 live += ((lnat)stp->hp_bd->free - (lnat)stp->hp_bd->start)
736 /* Approximate the number of blocks that will be needed at the next
737 * garbage collection.
739 * Assume: all data currently live will remain live. Steps that will
740 * be collected next time will therefore need twice as many blocks
741 * since all the data will be copied.
750 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
751 for (s = 0; s < generations[g].n_steps; s++) {
752 if (g == 0 && s == 0) { continue; }
753 stp = &generations[g].steps[s];
754 if (generations[g].steps[0].n_blocks +
755 generations[g].steps[0].n_large_blocks
756 > generations[g].max_blocks
757 && stp->is_compacted == 0) {
758 needed += 2 * stp->n_blocks;
760 needed += stp->n_blocks;
767 /* -----------------------------------------------------------------------------
770 memInventory() checks for memory leaks by counting up all the
771 blocks we know about and comparing that to the number of blocks
772 allegedly floating around in the system.
773 -------------------------------------------------------------------------- */
783 lnat total_blocks = 0, free_blocks = 0;
785 /* count the blocks we current have */
787 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
788 for (s = 0; s < generations[g].n_steps; s++) {
789 stp = &generations[g].steps[s];
790 total_blocks += stp->n_blocks;
791 if (RtsFlags.GcFlags.generations == 1) {
792 /* two-space collector has a to-space too :-) */
793 total_blocks += g0s0->n_to_blocks;
795 for (bd = stp->large_objects; bd; bd = bd->link) {
796 total_blocks += bd->blocks;
797 /* hack for megablock groups: they have an extra block or two in
798 the second and subsequent megablocks where the block
799 descriptors would normally go.
801 if (bd->blocks > BLOCKS_PER_MBLOCK) {
802 total_blocks -= (MBLOCK_SIZE / BLOCK_SIZE - BLOCKS_PER_MBLOCK)
803 * (bd->blocks/(MBLOCK_SIZE/BLOCK_SIZE));
809 /* any blocks held by allocate() */
810 for (bd = small_alloc_list; bd; bd = bd->link) {
811 total_blocks += bd->blocks;
815 if (RtsFlags.ProfFlags.doHeapProfile == HEAP_BY_RETAINER) {
816 for (bd = firstStack; bd != NULL; bd = bd->link)
817 total_blocks += bd->blocks;
821 // count the blocks allocated by the arena allocator
822 total_blocks += arenaBlocks();
824 /* count the blocks on the free list */
825 free_blocks = countFreeList();
827 if (total_blocks + free_blocks != mblocks_allocated *
829 fprintf(stderr, "Blocks: %ld live + %ld free = %ld total (%ld around)\n",
830 total_blocks, free_blocks, total_blocks + free_blocks,
831 mblocks_allocated * BLOCKS_PER_MBLOCK);
834 ASSERT(total_blocks + free_blocks == mblocks_allocated * BLOCKS_PER_MBLOCK);
839 countBlocks(bdescr *bd)
842 for (n=0; bd != NULL; bd=bd->link) {
848 /* Full heap sanity check. */
854 if (RtsFlags.GcFlags.generations == 1) {
855 checkHeap(g0s0->to_blocks);
856 checkChain(g0s0->large_objects);
859 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
860 for (s = 0; s < generations[g].n_steps; s++) {
861 ASSERT(countBlocks(generations[g].steps[s].blocks)
862 == generations[g].steps[s].n_blocks);
863 ASSERT(countBlocks(generations[g].steps[s].large_objects)
864 == generations[g].steps[s].n_large_blocks);
865 if (g == 0 && s == 0) { continue; }
866 checkHeap(generations[g].steps[s].blocks);
867 checkChain(generations[g].steps[s].large_objects);
869 checkMutableList(generations[g].mut_list, g);
870 checkMutOnceList(generations[g].mut_once_list, g);
874 checkFreeListSanity();
878 // handy function for use in gdb, because Bdescr() is inlined.
879 extern bdescr *_bdescr( StgPtr p );