Store a destination step in the block descriptor
[ghc.git] / rts / sm / Storage.c
1 /* -----------------------------------------------------------------------------
2 *
3 * (c) The GHC Team, 1998-2008
4 *
5 * Storage manager front end
6 *
7 * Documentation on the architecture of the Storage Manager can be
8 * found in the online commentary:
9 *
10 * http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/Storage
11 *
12 * ---------------------------------------------------------------------------*/
13
14 #include "PosixSource.h"
15 #include "Rts.h"
16
17 #include "Storage.h"
18 #include "RtsUtils.h"
19 #include "Stats.h"
20 #include "BlockAlloc.h"
21 #include "Weak.h"
22 #include "Sanity.h"
23 #include "Arena.h"
24 #include "Capability.h"
25 #include "Schedule.h"
26 #include "RetainerProfile.h" // for counting memory blocks (memInventory)
27 #include "OSMem.h"
28 #include "Trace.h"
29 #include "GC.h"
30 #include "Evac.h"
31
32 #include <string.h>
33
34 #include "ffi.h"
35
36 /*
37 * All these globals require sm_mutex to access in THREADED_RTS mode.
38 */
39 StgClosure *caf_list = NULL;
40 StgClosure *revertible_caf_list = NULL;
41 rtsBool keepCAFs;
42
43 bdescr *pinned_object_block; /* allocate pinned objects into this block */
44 nat alloc_blocks; /* number of allocate()d blocks since GC */
45 nat alloc_blocks_lim; /* approximate limit on alloc_blocks */
46
47 static bdescr *exec_block;
48
49 generation *generations = NULL; /* all the generations */
50 generation *g0 = NULL; /* generation 0, for convenience */
51 generation *oldest_gen = NULL; /* oldest generation, for convenience */
52 step *g0s0 = NULL; /* generation 0, step 0, for convenience */
53
54 nat total_steps = 0;
55 step *all_steps = NULL; /* single array of steps */
56
57 ullong total_allocated = 0; /* total memory allocated during run */
58
59 nat n_nurseries = 0; /* == RtsFlags.ParFlags.nNodes, convenience */
60 step *nurseries = NULL; /* array of nurseries, >1 only if THREADED_RTS */
61
62 #ifdef THREADED_RTS
63 /*
64 * Storage manager mutex: protects all the above state from
65 * simultaneous access by two STG threads.
66 */
67 Mutex sm_mutex;
68 #endif
69
70 static void allocNurseries ( void );
71
72 static void
73 initStep (step *stp, int g, int s)
74 {
75 stp->no = s;
76 stp->abs_no = RtsFlags.GcFlags.steps * g + s;
77 stp->blocks = NULL;
78 stp->n_blocks = 0;
79 stp->n_words = 0;
80 stp->live_estimate = 0;
81 stp->old_blocks = NULL;
82 stp->n_old_blocks = 0;
83 stp->gen = &generations[g];
84 stp->gen_no = g;
85 stp->large_objects = NULL;
86 stp->n_large_blocks = 0;
87 stp->scavenged_large_objects = NULL;
88 stp->n_scavenged_large_blocks = 0;
89 stp->mark = 0;
90 stp->compact = 0;
91 stp->bitmap = NULL;
92 #ifdef THREADED_RTS
93 initSpinLock(&stp->sync_large_objects);
94 #endif
95 stp->threads = END_TSO_QUEUE;
96 stp->old_threads = END_TSO_QUEUE;
97 }
98
99 void
100 initStorage( void )
101 {
102 nat g, s;
103 generation *gen;
104
105 if (generations != NULL) {
106 // multi-init protection
107 return;
108 }
109
110 initMBlocks();
111
112 /* Sanity check to make sure the LOOKS_LIKE_ macros appear to be
113 * doing something reasonable.
114 */
115 /* We use the NOT_NULL variant or gcc warns that the test is always true */
116 ASSERT(LOOKS_LIKE_INFO_PTR_NOT_NULL((StgWord)&stg_BLACKHOLE_info));
117 ASSERT(LOOKS_LIKE_CLOSURE_PTR(&stg_dummy_ret_closure));
118 ASSERT(!HEAP_ALLOCED(&stg_dummy_ret_closure));
119
120 if (RtsFlags.GcFlags.maxHeapSize != 0 &&
121 RtsFlags.GcFlags.heapSizeSuggestion >
122 RtsFlags.GcFlags.maxHeapSize) {
123 RtsFlags.GcFlags.maxHeapSize = RtsFlags.GcFlags.heapSizeSuggestion;
124 }
125
126 if (RtsFlags.GcFlags.maxHeapSize != 0 &&
127 RtsFlags.GcFlags.minAllocAreaSize >
128 RtsFlags.GcFlags.maxHeapSize) {
129 errorBelch("maximum heap size (-M) is smaller than minimum alloc area size (-A)");
130 RtsFlags.GcFlags.minAllocAreaSize = RtsFlags.GcFlags.maxHeapSize;
131 }
132
133 initBlockAllocator();
134
135 #if defined(THREADED_RTS)
136 initMutex(&sm_mutex);
137 #endif
138
139 ACQUIRE_SM_LOCK;
140
141 /* allocate generation info array */
142 generations = (generation *)stgMallocBytes(RtsFlags.GcFlags.generations
143 * sizeof(struct generation_),
144 "initStorage: gens");
145
146 /* allocate all the steps into an array. It is important that we do
147 it this way, because we need the invariant that two step pointers
148 can be directly compared to see which is the oldest.
149 Remember that the last generation has only one step. */
150 total_steps = 1 + (RtsFlags.GcFlags.generations - 1) * RtsFlags.GcFlags.steps;
151 all_steps = stgMallocBytes(total_steps * sizeof(struct step_),
152 "initStorage: steps");
153
154 /* Initialise all generations */
155 for(g = 0; g < RtsFlags.GcFlags.generations; g++) {
156 gen = &generations[g];
157 gen->no = g;
158 gen->mut_list = allocBlock();
159 gen->collections = 0;
160 gen->par_collections = 0;
161 gen->failed_promotions = 0;
162 gen->max_blocks = 0;
163 }
164
165 /* A couple of convenience pointers */
166 g0 = &generations[0];
167 oldest_gen = &generations[RtsFlags.GcFlags.generations-1];
168
169 /* Allocate step structures in each generation */
170 if (RtsFlags.GcFlags.generations > 1) {
171 /* Only for multiple-generations */
172
173 /* Oldest generation: one step */
174 oldest_gen->n_steps = 1;
175 oldest_gen->steps = all_steps + (RtsFlags.GcFlags.generations - 1)
176 * RtsFlags.GcFlags.steps;
177
178 /* set up all except the oldest generation with 2 steps */
179 for(g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
180 generations[g].n_steps = RtsFlags.GcFlags.steps;
181 generations[g].steps = all_steps + g * RtsFlags.GcFlags.steps;
182 }
183
184 } else {
185 /* single generation, i.e. a two-space collector */
186 g0->n_steps = 1;
187 g0->steps = all_steps;
188 }
189
190 #ifdef THREADED_RTS
191 n_nurseries = n_capabilities;
192 #else
193 n_nurseries = 1;
194 #endif
195 nurseries = stgMallocBytes (n_nurseries * sizeof(struct step_),
196 "initStorage: nurseries");
197
198 /* Initialise all steps */
199 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
200 for (s = 0; s < generations[g].n_steps; s++) {
201 initStep(&generations[g].steps[s], g, s);
202 }
203 }
204
205 for (s = 0; s < n_nurseries; s++) {
206 initStep(&nurseries[s], 0, s);
207 }
208
209 /* Set up the destination pointers in each younger gen. step */
210 for (g = 0; g < RtsFlags.GcFlags.generations-1; g++) {
211 for (s = 0; s < generations[g].n_steps-1; s++) {
212 generations[g].steps[s].to = &generations[g].steps[s+1];
213 }
214 generations[g].steps[s].to = &generations[g+1].steps[0];
215 }
216 oldest_gen->steps[0].to = &oldest_gen->steps[0];
217
218 for (s = 0; s < n_nurseries; s++) {
219 nurseries[s].to = generations[0].steps[0].to;
220 }
221
222 /* The oldest generation has one step. */
223 if (RtsFlags.GcFlags.compact || RtsFlags.GcFlags.sweep) {
224 if (RtsFlags.GcFlags.generations == 1) {
225 errorBelch("WARNING: compact/sweep is incompatible with -G1; disabled");
226 } else {
227 oldest_gen->steps[0].mark = 1;
228 if (RtsFlags.GcFlags.compact)
229 oldest_gen->steps[0].compact = 1;
230 }
231 }
232
233 generations[0].max_blocks = 0;
234 g0s0 = &generations[0].steps[0];
235
236 /* The allocation area. Policy: keep the allocation area
237 * small to begin with, even if we have a large suggested heap
238 * size. Reason: we're going to do a major collection first, and we
239 * don't want it to be a big one. This vague idea is borne out by
240 * rigorous experimental evidence.
241 */
242 allocNurseries();
243
244 weak_ptr_list = NULL;
245 caf_list = NULL;
246 revertible_caf_list = NULL;
247
248 /* initialise the allocate() interface */
249 alloc_blocks = 0;
250 alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
251
252 exec_block = NULL;
253
254 #ifdef THREADED_RTS
255 initSpinLock(&gc_alloc_block_sync);
256 whitehole_spin = 0;
257 #endif
258
259 N = 0;
260
261 initGcThreads();
262
263 IF_DEBUG(gc, statDescribeGens());
264
265 RELEASE_SM_LOCK;
266 }
267
268 void
269 exitStorage (void)
270 {
271 stat_exit(calcAllocated());
272 }
273
274 void
275 freeStorage (void)
276 {
277 stgFree(g0s0); // frees all the steps
278 stgFree(generations);
279 freeAllMBlocks();
280 #if defined(THREADED_RTS)
281 closeMutex(&sm_mutex);
282 #endif
283 stgFree(nurseries);
284 freeGcThreads();
285 }
286
287 /* -----------------------------------------------------------------------------
288 CAF management.
289
290 The entry code for every CAF does the following:
291
292 - builds a CAF_BLACKHOLE in the heap
293 - pushes an update frame pointing to the CAF_BLACKHOLE
294 - invokes UPD_CAF(), which:
295 - calls newCaf, below
296 - updates the CAF with a static indirection to the CAF_BLACKHOLE
297
298 Why do we build a BLACKHOLE in the heap rather than just updating
299 the thunk directly? It's so that we only need one kind of update
300 frame - otherwise we'd need a static version of the update frame too.
301
302 newCaf() does the following:
303
304 - it puts the CAF on the oldest generation's mut-once list.
305 This is so that we can treat the CAF as a root when collecting
306 younger generations.
307
308 For GHCI, we have additional requirements when dealing with CAFs:
309
310 - we must *retain* all dynamically-loaded CAFs ever entered,
311 just in case we need them again.
312 - we must be able to *revert* CAFs that have been evaluated, to
313 their pre-evaluated form.
314
315 To do this, we use an additional CAF list. When newCaf() is
316 called on a dynamically-loaded CAF, we add it to the CAF list
317 instead of the old-generation mutable list, and save away its
318 old info pointer (in caf->saved_info) for later reversion.
319
320 To revert all the CAFs, we traverse the CAF list and reset the
321 info pointer to caf->saved_info, then throw away the CAF list.
322 (see GC.c:revertCAFs()).
323
324 -- SDM 29/1/01
325
326 -------------------------------------------------------------------------- */
327
328 void
329 newCAF(StgClosure* caf)
330 {
331 ACQUIRE_SM_LOCK;
332
333 #ifdef DYNAMIC
334 if(keepCAFs)
335 {
336 // HACK:
337 // If we are in GHCi _and_ we are using dynamic libraries,
338 // then we can't redirect newCAF calls to newDynCAF (see below),
339 // so we make newCAF behave almost like newDynCAF.
340 // The dynamic libraries might be used by both the interpreted
341 // program and GHCi itself, so they must not be reverted.
342 // This also means that in GHCi with dynamic libraries, CAFs are not
343 // garbage collected. If this turns out to be a problem, we could
344 // do another hack here and do an address range test on caf to figure
345 // out whether it is from a dynamic library.
346 ((StgIndStatic *)caf)->saved_info = (StgInfoTable *)caf->header.info;
347 ((StgIndStatic *)caf)->static_link = caf_list;
348 caf_list = caf;
349 }
350 else
351 #endif
352 {
353 /* Put this CAF on the mutable list for the old generation.
354 * This is a HACK - the IND_STATIC closure doesn't really have
355 * a mut_link field, but we pretend it has - in fact we re-use
356 * the STATIC_LINK field for the time being, because when we
357 * come to do a major GC we won't need the mut_link field
358 * any more and can use it as a STATIC_LINK.
359 */
360 ((StgIndStatic *)caf)->saved_info = NULL;
361 recordMutableGen(caf, oldest_gen->no);
362 }
363
364 RELEASE_SM_LOCK;
365 }
366
367 // An alternate version of newCaf which is used for dynamically loaded
368 // object code in GHCi. In this case we want to retain *all* CAFs in
369 // the object code, because they might be demanded at any time from an
370 // expression evaluated on the command line.
371 // Also, GHCi might want to revert CAFs, so we add these to the
372 // revertible_caf_list.
373 //
374 // The linker hackily arranges that references to newCaf from dynamic
375 // code end up pointing to newDynCAF.
376 void
377 newDynCAF(StgClosure *caf)
378 {
379 ACQUIRE_SM_LOCK;
380
381 ((StgIndStatic *)caf)->saved_info = (StgInfoTable *)caf->header.info;
382 ((StgIndStatic *)caf)->static_link = revertible_caf_list;
383 revertible_caf_list = caf;
384
385 RELEASE_SM_LOCK;
386 }
387
388 /* -----------------------------------------------------------------------------
389 Nursery management.
390 -------------------------------------------------------------------------- */
391
392 static bdescr *
393 allocNursery (step *stp, bdescr *tail, nat blocks)
394 {
395 bdescr *bd;
396 nat i;
397
398 // Allocate a nursery: we allocate fresh blocks one at a time and
399 // cons them on to the front of the list, not forgetting to update
400 // the back pointer on the tail of the list to point to the new block.
401 for (i=0; i < blocks; i++) {
402 // @LDV profiling
403 /*
404 processNursery() in LdvProfile.c assumes that every block group in
405 the nursery contains only a single block. So, if a block group is
406 given multiple blocks, change processNursery() accordingly.
407 */
408 bd = allocBlock();
409 bd->link = tail;
410 // double-link the nursery: we might need to insert blocks
411 if (tail != NULL) {
412 tail->u.back = bd;
413 }
414 initBdescr(bd, stp);
415 bd->flags = 0;
416 bd->free = bd->start;
417 tail = bd;
418 }
419 tail->u.back = NULL;
420 return tail;
421 }
422
423 static void
424 assignNurseriesToCapabilities (void)
425 {
426 #ifdef THREADED_RTS
427 nat i;
428
429 for (i = 0; i < n_nurseries; i++) {
430 capabilities[i].r.rNursery = &nurseries[i];
431 capabilities[i].r.rCurrentNursery = nurseries[i].blocks;
432 capabilities[i].r.rCurrentAlloc = NULL;
433 }
434 #else /* THREADED_RTS */
435 MainCapability.r.rNursery = &nurseries[0];
436 MainCapability.r.rCurrentNursery = nurseries[0].blocks;
437 MainCapability.r.rCurrentAlloc = NULL;
438 #endif
439 }
440
441 static void
442 allocNurseries( void )
443 {
444 nat i;
445
446 for (i = 0; i < n_nurseries; i++) {
447 nurseries[i].blocks =
448 allocNursery(&nurseries[i], NULL,
449 RtsFlags.GcFlags.minAllocAreaSize);
450 nurseries[i].n_blocks = RtsFlags.GcFlags.minAllocAreaSize;
451 nurseries[i].old_blocks = NULL;
452 nurseries[i].n_old_blocks = 0;
453 }
454 assignNurseriesToCapabilities();
455 }
456
457 void
458 resetNurseries( void )
459 {
460 nat i;
461 bdescr *bd;
462 step *stp;
463
464 for (i = 0; i < n_nurseries; i++) {
465 stp = &nurseries[i];
466 for (bd = stp->blocks; bd; bd = bd->link) {
467 bd->free = bd->start;
468 ASSERT(bd->gen_no == 0);
469 ASSERT(bd->step == stp);
470 IF_DEBUG(sanity,memset(bd->start, 0xaa, BLOCK_SIZE));
471 }
472 }
473 assignNurseriesToCapabilities();
474 }
475
476 lnat
477 countNurseryBlocks (void)
478 {
479 nat i;
480 lnat blocks = 0;
481
482 for (i = 0; i < n_nurseries; i++) {
483 blocks += nurseries[i].n_blocks;
484 }
485 return blocks;
486 }
487
488 static void
489 resizeNursery ( step *stp, nat blocks )
490 {
491 bdescr *bd;
492 nat nursery_blocks;
493
494 nursery_blocks = stp->n_blocks;
495 if (nursery_blocks == blocks) return;
496
497 if (nursery_blocks < blocks) {
498 debugTrace(DEBUG_gc, "increasing size of nursery to %d blocks",
499 blocks);
500 stp->blocks = allocNursery(stp, stp->blocks, blocks-nursery_blocks);
501 }
502 else {
503 bdescr *next_bd;
504
505 debugTrace(DEBUG_gc, "decreasing size of nursery to %d blocks",
506 blocks);
507
508 bd = stp->blocks;
509 while (nursery_blocks > blocks) {
510 next_bd = bd->link;
511 next_bd->u.back = NULL;
512 nursery_blocks -= bd->blocks; // might be a large block
513 freeGroup(bd);
514 bd = next_bd;
515 }
516 stp->blocks = bd;
517 // might have gone just under, by freeing a large block, so make
518 // up the difference.
519 if (nursery_blocks < blocks) {
520 stp->blocks = allocNursery(stp, stp->blocks, blocks-nursery_blocks);
521 }
522 }
523
524 stp->n_blocks = blocks;
525 ASSERT(countBlocks(stp->blocks) == stp->n_blocks);
526 }
527
528 //
529 // Resize each of the nurseries to the specified size.
530 //
531 void
532 resizeNurseriesFixed (nat blocks)
533 {
534 nat i;
535 for (i = 0; i < n_nurseries; i++) {
536 resizeNursery(&nurseries[i], blocks);
537 }
538 }
539
540 //
541 // Resize the nurseries to the total specified size.
542 //
543 void
544 resizeNurseries (nat blocks)
545 {
546 // If there are multiple nurseries, then we just divide the number
547 // of available blocks between them.
548 resizeNurseriesFixed(blocks / n_nurseries);
549 }
550
551
552 /* -----------------------------------------------------------------------------
553 move_TSO is called to update the TSO structure after it has been
554 moved from one place to another.
555 -------------------------------------------------------------------------- */
556
557 void
558 move_TSO (StgTSO *src, StgTSO *dest)
559 {
560 ptrdiff_t diff;
561
562 // relocate the stack pointer...
563 diff = (StgPtr)dest - (StgPtr)src; // In *words*
564 dest->sp = (StgPtr)dest->sp + diff;
565 }
566
567 /* -----------------------------------------------------------------------------
568 The allocate() interface
569
570 allocateInGen() function allocates memory directly into a specific
571 generation. It always succeeds, and returns a chunk of memory n
572 words long. n can be larger than the size of a block if necessary,
573 in which case a contiguous block group will be allocated.
574
575 allocate(n) is equivalent to allocateInGen(g0).
576 -------------------------------------------------------------------------- */
577
578 StgPtr
579 allocateInGen (generation *g, lnat n)
580 {
581 step *stp;
582 bdescr *bd;
583 StgPtr ret;
584
585 ACQUIRE_SM_LOCK;
586
587 TICK_ALLOC_HEAP_NOCTR(n);
588 CCS_ALLOC(CCCS,n);
589
590 stp = &g->steps[0];
591
592 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_))
593 {
594 lnat req_blocks = (lnat)BLOCK_ROUND_UP(n*sizeof(W_)) / BLOCK_SIZE;
595
596 // Attempting to allocate an object larger than maxHeapSize
597 // should definitely be disallowed. (bug #1791)
598 if (RtsFlags.GcFlags.maxHeapSize > 0 &&
599 req_blocks >= RtsFlags.GcFlags.maxHeapSize) {
600 heapOverflow();
601 // heapOverflow() doesn't exit (see #2592), but we aren't
602 // in a position to do a clean shutdown here: we
603 // either have to allocate the memory or exit now.
604 // Allocating the memory would be bad, because the user
605 // has requested that we not exceed maxHeapSize, so we
606 // just exit.
607 stg_exit(EXIT_HEAPOVERFLOW);
608 }
609
610 bd = allocGroup(req_blocks);
611 dbl_link_onto(bd, &stp->large_objects);
612 stp->n_large_blocks += bd->blocks; // might be larger than req_blocks
613 alloc_blocks += bd->blocks;
614 initBdescr(bd, stp);
615 bd->flags = BF_LARGE;
616 bd->free = bd->start + n;
617 ret = bd->start;
618 }
619 else
620 {
621 // small allocation (<LARGE_OBJECT_THRESHOLD) */
622 bd = stp->blocks;
623 if (bd == NULL || bd->free + n > bd->start + BLOCK_SIZE_W) {
624 bd = allocBlock();
625 initBdescr(bd, stp);
626 bd->flags = 0;
627 bd->link = stp->blocks;
628 stp->blocks = bd;
629 stp->n_blocks++;
630 alloc_blocks++;
631 }
632 ret = bd->free;
633 bd->free += n;
634 }
635
636 RELEASE_SM_LOCK;
637
638 return ret;
639 }
640
641 StgPtr
642 allocate (lnat n)
643 {
644 return allocateInGen(g0,n);
645 }
646
647 lnat
648 allocatedBytes( void )
649 {
650 lnat allocated;
651
652 allocated = alloc_blocks * BLOCK_SIZE_W;
653 if (pinned_object_block != NULL) {
654 allocated -= (pinned_object_block->start + BLOCK_SIZE_W) -
655 pinned_object_block->free;
656 }
657
658 return allocated;
659 }
660
661 // split N blocks off the front of the given bdescr, returning the
662 // new block group. We treat the remainder as if it
663 // had been freshly allocated in generation 0.
664 bdescr *
665 splitLargeBlock (bdescr *bd, nat blocks)
666 {
667 bdescr *new_bd;
668
669 // subtract the original number of blocks from the counter first
670 bd->step->n_large_blocks -= bd->blocks;
671
672 new_bd = splitBlockGroup (bd, blocks);
673
674 dbl_link_onto(new_bd, &g0s0->large_objects);
675 g0s0->n_large_blocks += new_bd->blocks;
676 initBdescr(new_bd, g0s0);
677 new_bd->flags = BF_LARGE;
678 new_bd->free = bd->free;
679 ASSERT(new_bd->free <= new_bd->start + new_bd->blocks * BLOCK_SIZE_W);
680
681 // add the new number of blocks to the counter. Due to the gaps
682 // for block descriptor, new_bd->blocks + bd->blocks might not be
683 // equal to the original bd->blocks, which is why we do it this way.
684 bd->step->n_large_blocks += bd->blocks;
685
686 return new_bd;
687 }
688
689 /* -----------------------------------------------------------------------------
690 allocateLocal()
691
692 This allocates memory in the current thread - it is intended for
693 use primarily from STG-land where we have a Capability. It is
694 better than allocate() because it doesn't require taking the
695 sm_mutex lock in the common case.
696
697 Memory is allocated directly from the nursery if possible (but not
698 from the current nursery block, so as not to interfere with
699 Hp/HpLim).
700 -------------------------------------------------------------------------- */
701
702 StgPtr
703 allocateLocal (Capability *cap, lnat n)
704 {
705 bdescr *bd;
706 StgPtr p;
707
708 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
709 return allocateInGen(g0,n);
710 }
711
712 /* small allocation (<LARGE_OBJECT_THRESHOLD) */
713
714 TICK_ALLOC_HEAP_NOCTR(n);
715 CCS_ALLOC(CCCS,n);
716
717 bd = cap->r.rCurrentAlloc;
718 if (bd == NULL || bd->free + n > bd->start + BLOCK_SIZE_W) {
719
720 // The CurrentAlloc block is full, we need to find another
721 // one. First, we try taking the next block from the
722 // nursery:
723 bd = cap->r.rCurrentNursery->link;
724
725 if (bd == NULL || bd->free + n > bd->start + BLOCK_SIZE_W) {
726 // The nursery is empty, or the next block is already
727 // full: allocate a fresh block (we can't fail here).
728 ACQUIRE_SM_LOCK;
729 bd = allocBlock();
730 cap->r.rNursery->n_blocks++;
731 RELEASE_SM_LOCK;
732 initBdescr(bd, cap->r.rNursery);
733 bd->flags = 0;
734 // NO: alloc_blocks++;
735 // calcAllocated() uses the size of the nursery, and we've
736 // already bumpted nursery->n_blocks above. We'll GC
737 // pretty quickly now anyway, because MAYBE_GC() will
738 // notice that CurrentNursery->link is NULL.
739 } else {
740 // we have a block in the nursery: take it and put
741 // it at the *front* of the nursery list, and use it
742 // to allocate() from.
743 cap->r.rCurrentNursery->link = bd->link;
744 if (bd->link != NULL) {
745 bd->link->u.back = cap->r.rCurrentNursery;
746 }
747 }
748 dbl_link_onto(bd, &cap->r.rNursery->blocks);
749 cap->r.rCurrentAlloc = bd;
750 IF_DEBUG(sanity, checkNurserySanity(cap->r.rNursery));
751 }
752 p = bd->free;
753 bd->free += n;
754 return p;
755 }
756
757 /* ---------------------------------------------------------------------------
758 Allocate a fixed/pinned object.
759
760 We allocate small pinned objects into a single block, allocating a
761 new block when the current one overflows. The block is chained
762 onto the large_object_list of generation 0 step 0.
763
764 NOTE: The GC can't in general handle pinned objects. This
765 interface is only safe to use for ByteArrays, which have no
766 pointers and don't require scavenging. It works because the
767 block's descriptor has the BF_LARGE flag set, so the block is
768 treated as a large object and chained onto various lists, rather
769 than the individual objects being copied. However, when it comes
770 to scavenge the block, the GC will only scavenge the first object.
771 The reason is that the GC can't linearly scan a block of pinned
772 objects at the moment (doing so would require using the
773 mostly-copying techniques). But since we're restricting ourselves
774 to pinned ByteArrays, not scavenging is ok.
775
776 This function is called by newPinnedByteArray# which immediately
777 fills the allocated memory with a MutableByteArray#.
778 ------------------------------------------------------------------------- */
779
780 StgPtr
781 allocatePinned( lnat n )
782 {
783 StgPtr p;
784 bdescr *bd = pinned_object_block;
785
786 // If the request is for a large object, then allocate()
787 // will give us a pinned object anyway.
788 if (n >= LARGE_OBJECT_THRESHOLD/sizeof(W_)) {
789 p = allocate(n);
790 Bdescr(p)->flags |= BF_PINNED;
791 return p;
792 }
793
794 ACQUIRE_SM_LOCK;
795
796 TICK_ALLOC_HEAP_NOCTR(n);
797 CCS_ALLOC(CCCS,n);
798
799 // If we don't have a block of pinned objects yet, or the current
800 // one isn't large enough to hold the new object, allocate a new one.
801 if (bd == NULL || (bd->free + n) > (bd->start + BLOCK_SIZE_W)) {
802 pinned_object_block = bd = allocBlock();
803 dbl_link_onto(bd, &g0s0->large_objects);
804 g0s0->n_large_blocks++;
805 initBdescr(bd, g0s0);
806 bd->flags = BF_PINNED | BF_LARGE;
807 bd->free = bd->start;
808 alloc_blocks++;
809 }
810
811 p = bd->free;
812 bd->free += n;
813 RELEASE_SM_LOCK;
814 return p;
815 }
816
817 /* -----------------------------------------------------------------------------
818 Write Barriers
819 -------------------------------------------------------------------------- */
820
821 /*
822 This is the write barrier for MUT_VARs, a.k.a. IORefs. A
823 MUT_VAR_CLEAN object is not on the mutable list; a MUT_VAR_DIRTY
824 is. When written to, a MUT_VAR_CLEAN turns into a MUT_VAR_DIRTY
825 and is put on the mutable list.
826 */
827 void
828 dirty_MUT_VAR(StgRegTable *reg, StgClosure *p)
829 {
830 Capability *cap = regTableToCapability(reg);
831 bdescr *bd;
832 if (p->header.info == &stg_MUT_VAR_CLEAN_info) {
833 p->header.info = &stg_MUT_VAR_DIRTY_info;
834 bd = Bdescr((StgPtr)p);
835 if (bd->gen_no > 0) recordMutableCap(p,cap,bd->gen_no);
836 }
837 }
838
839 // Setting a TSO's link field with a write barrier.
840 // It is *not* necessary to call this function when
841 // * setting the link field to END_TSO_QUEUE
842 // * putting a TSO on the blackhole_queue
843 // * setting the link field of the currently running TSO, as it
844 // will already be dirty.
845 void
846 setTSOLink (Capability *cap, StgTSO *tso, StgTSO *target)
847 {
848 bdescr *bd;
849 if (tso->dirty == 0 && (tso->flags & TSO_LINK_DIRTY) == 0) {
850 tso->flags |= TSO_LINK_DIRTY;
851 bd = Bdescr((StgPtr)tso);
852 if (bd->gen_no > 0) recordMutableCap((StgClosure*)tso,cap,bd->gen_no);
853 }
854 tso->_link = target;
855 }
856
857 void
858 dirty_TSO (Capability *cap, StgTSO *tso)
859 {
860 bdescr *bd;
861 if (tso->dirty == 0 && (tso->flags & TSO_LINK_DIRTY) == 0) {
862 bd = Bdescr((StgPtr)tso);
863 if (bd->gen_no > 0) recordMutableCap((StgClosure*)tso,cap,bd->gen_no);
864 }
865 tso->dirty = 1;
866 }
867
868 /*
869 This is the write barrier for MVARs. An MVAR_CLEAN objects is not
870 on the mutable list; a MVAR_DIRTY is. When written to, a
871 MVAR_CLEAN turns into a MVAR_DIRTY and is put on the mutable list.
872 The check for MVAR_CLEAN is inlined at the call site for speed,
873 this really does make a difference on concurrency-heavy benchmarks
874 such as Chaneneos and cheap-concurrency.
875 */
876 void
877 dirty_MVAR(StgRegTable *reg, StgClosure *p)
878 {
879 Capability *cap = regTableToCapability(reg);
880 bdescr *bd;
881 bd = Bdescr((StgPtr)p);
882 if (bd->gen_no > 0) recordMutableCap(p,cap,bd->gen_no);
883 }
884
885 /* -----------------------------------------------------------------------------
886 * Stats and stuff
887 * -------------------------------------------------------------------------- */
888
889 /* -----------------------------------------------------------------------------
890 * calcAllocated()
891 *
892 * Approximate how much we've allocated: number of blocks in the
893 * nursery + blocks allocated via allocate() - unused nusery blocks.
894 * This leaves a little slop at the end of each block, and doesn't
895 * take into account large objects (ToDo).
896 * -------------------------------------------------------------------------- */
897
898 lnat
899 calcAllocated( void )
900 {
901 nat allocated;
902 bdescr *bd;
903
904 allocated = allocatedBytes();
905 allocated += countNurseryBlocks() * BLOCK_SIZE_W;
906
907 {
908 #ifdef THREADED_RTS
909 nat i;
910 for (i = 0; i < n_nurseries; i++) {
911 Capability *cap;
912 for ( bd = capabilities[i].r.rCurrentNursery->link;
913 bd != NULL; bd = bd->link ) {
914 allocated -= BLOCK_SIZE_W;
915 }
916 cap = &capabilities[i];
917 if (cap->r.rCurrentNursery->free <
918 cap->r.rCurrentNursery->start + BLOCK_SIZE_W) {
919 allocated -= (cap->r.rCurrentNursery->start + BLOCK_SIZE_W)
920 - cap->r.rCurrentNursery->free;
921 }
922 }
923 #else
924 bdescr *current_nursery = MainCapability.r.rCurrentNursery;
925
926 for ( bd = current_nursery->link; bd != NULL; bd = bd->link ) {
927 allocated -= BLOCK_SIZE_W;
928 }
929 if (current_nursery->free < current_nursery->start + BLOCK_SIZE_W) {
930 allocated -= (current_nursery->start + BLOCK_SIZE_W)
931 - current_nursery->free;
932 }
933 #endif
934 }
935
936 total_allocated += allocated;
937 return allocated;
938 }
939
940 /* Approximate the amount of live data in the heap. To be called just
941 * after garbage collection (see GarbageCollect()).
942 */
943 lnat
944 calcLiveBlocks(void)
945 {
946 nat g, s;
947 lnat live = 0;
948 step *stp;
949
950 if (RtsFlags.GcFlags.generations == 1) {
951 return g0s0->n_large_blocks + g0s0->n_blocks;
952 }
953
954 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
955 for (s = 0; s < generations[g].n_steps; s++) {
956 /* approximate amount of live data (doesn't take into account slop
957 * at end of each block).
958 */
959 if (g == 0 && s == 0) {
960 continue;
961 }
962 stp = &generations[g].steps[s];
963 live += stp->n_large_blocks + stp->n_blocks;
964 }
965 }
966 return live;
967 }
968
969 lnat
970 countOccupied(bdescr *bd)
971 {
972 lnat words;
973
974 words = 0;
975 for (; bd != NULL; bd = bd->link) {
976 ASSERT(bd->free <= bd->start + bd->blocks * BLOCK_SIZE_W);
977 words += bd->free - bd->start;
978 }
979 return words;
980 }
981
982 // Return an accurate count of the live data in the heap, excluding
983 // generation 0.
984 lnat
985 calcLiveWords(void)
986 {
987 nat g, s;
988 lnat live;
989 step *stp;
990
991 if (RtsFlags.GcFlags.generations == 1) {
992 return g0s0->n_words + countOccupied(g0s0->large_objects);
993 }
994
995 live = 0;
996 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
997 for (s = 0; s < generations[g].n_steps; s++) {
998 if (g == 0 && s == 0) continue;
999 stp = &generations[g].steps[s];
1000 live += stp->n_words + countOccupied(stp->large_objects);
1001 }
1002 }
1003 return live;
1004 }
1005
1006 /* Approximate the number of blocks that will be needed at the next
1007 * garbage collection.
1008 *
1009 * Assume: all data currently live will remain live. Steps that will
1010 * be collected next time will therefore need twice as many blocks
1011 * since all the data will be copied.
1012 */
1013 extern lnat
1014 calcNeeded(void)
1015 {
1016 lnat needed = 0;
1017 nat g, s;
1018 step *stp;
1019
1020 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
1021 for (s = 0; s < generations[g].n_steps; s++) {
1022 if (g == 0 && s == 0) { continue; }
1023 stp = &generations[g].steps[s];
1024
1025 // we need at least this much space
1026 needed += stp->n_blocks + stp->n_large_blocks;
1027
1028 // any additional space needed to collect this gen next time?
1029 if (g == 0 || // always collect gen 0
1030 (generations[g].steps[0].n_blocks +
1031 generations[g].steps[0].n_large_blocks
1032 > generations[g].max_blocks)) {
1033 // we will collect this gen next time
1034 if (stp->mark) {
1035 // bitmap:
1036 needed += stp->n_blocks / BITS_IN(W_);
1037 // mark stack:
1038 needed += stp->n_blocks / 100;
1039 }
1040 if (stp->compact) {
1041 continue; // no additional space needed for compaction
1042 } else {
1043 needed += stp->n_blocks;
1044 }
1045 }
1046 }
1047 }
1048 return needed;
1049 }
1050
1051 /* ----------------------------------------------------------------------------
1052 Executable memory
1053
1054 Executable memory must be managed separately from non-executable
1055 memory. Most OSs these days require you to jump through hoops to
1056 dynamically allocate executable memory, due to various security
1057 measures.
1058
1059 Here we provide a small memory allocator for executable memory.
1060 Memory is managed with a page granularity; we allocate linearly
1061 in the page, and when the page is emptied (all objects on the page
1062 are free) we free the page again, not forgetting to make it
1063 non-executable.
1064
1065 TODO: The inability to handle objects bigger than BLOCK_SIZE_W means that
1066 the linker cannot use allocateExec for loading object code files
1067 on Windows. Once allocateExec can handle larger objects, the linker
1068 should be modified to use allocateExec instead of VirtualAlloc.
1069 ------------------------------------------------------------------------- */
1070
1071 #if defined(linux_HOST_OS)
1072
1073 // On Linux we need to use libffi for allocating executable memory,
1074 // because it knows how to work around the restrictions put in place
1075 // by SELinux.
1076
1077 void *allocateExec (nat bytes, void **exec_ret)
1078 {
1079 void **ret, **exec;
1080 ACQUIRE_SM_LOCK;
1081 ret = ffi_closure_alloc (sizeof(void *) + (size_t)bytes, (void**)&exec);
1082 RELEASE_SM_LOCK;
1083 if (ret == NULL) return ret;
1084 *ret = ret; // save the address of the writable mapping, for freeExec().
1085 *exec_ret = exec + 1;
1086 return (ret + 1);
1087 }
1088
1089 // freeExec gets passed the executable address, not the writable address.
1090 void freeExec (void *addr)
1091 {
1092 void *writable;
1093 writable = *((void**)addr - 1);
1094 ACQUIRE_SM_LOCK;
1095 ffi_closure_free (writable);
1096 RELEASE_SM_LOCK
1097 }
1098
1099 #else
1100
1101 void *allocateExec (nat bytes, void **exec_ret)
1102 {
1103 void *ret;
1104 nat n;
1105
1106 ACQUIRE_SM_LOCK;
1107
1108 // round up to words.
1109 n = (bytes + sizeof(W_) + 1) / sizeof(W_);
1110
1111 if (n+1 > BLOCK_SIZE_W) {
1112 barf("allocateExec: can't handle large objects");
1113 }
1114
1115 if (exec_block == NULL ||
1116 exec_block->free + n + 1 > exec_block->start + BLOCK_SIZE_W) {
1117 bdescr *bd;
1118 lnat pagesize = getPageSize();
1119 bd = allocGroup(stg_max(1, pagesize / BLOCK_SIZE));
1120 debugTrace(DEBUG_gc, "allocate exec block %p", bd->start);
1121 bd->gen_no = 0;
1122 bd->flags = BF_EXEC;
1123 bd->link = exec_block;
1124 if (exec_block != NULL) {
1125 exec_block->u.back = bd;
1126 }
1127 bd->u.back = NULL;
1128 setExecutable(bd->start, bd->blocks * BLOCK_SIZE, rtsTrue);
1129 exec_block = bd;
1130 }
1131 *(exec_block->free) = n; // store the size of this chunk
1132 exec_block->gen_no += n; // gen_no stores the number of words allocated
1133 ret = exec_block->free + 1;
1134 exec_block->free += n + 1;
1135
1136 RELEASE_SM_LOCK
1137 *exec_ret = ret;
1138 return ret;
1139 }
1140
1141 void freeExec (void *addr)
1142 {
1143 StgPtr p = (StgPtr)addr - 1;
1144 bdescr *bd = Bdescr((StgPtr)p);
1145
1146 if ((bd->flags & BF_EXEC) == 0) {
1147 barf("freeExec: not executable");
1148 }
1149
1150 if (*(StgPtr)p == 0) {
1151 barf("freeExec: already free?");
1152 }
1153
1154 ACQUIRE_SM_LOCK;
1155
1156 bd->gen_no -= *(StgPtr)p;
1157 *(StgPtr)p = 0;
1158
1159 if (bd->gen_no == 0) {
1160 // Free the block if it is empty, but not if it is the block at
1161 // the head of the queue.
1162 if (bd != exec_block) {
1163 debugTrace(DEBUG_gc, "free exec block %p", bd->start);
1164 dbl_link_remove(bd, &exec_block);
1165 setExecutable(bd->start, bd->blocks * BLOCK_SIZE, rtsFalse);
1166 freeGroup(bd);
1167 } else {
1168 bd->free = bd->start;
1169 }
1170 }
1171
1172 RELEASE_SM_LOCK
1173 }
1174
1175 #endif /* mingw32_HOST_OS */
1176
1177 /* -----------------------------------------------------------------------------
1178 Debugging
1179
1180 memInventory() checks for memory leaks by counting up all the
1181 blocks we know about and comparing that to the number of blocks
1182 allegedly floating around in the system.
1183 -------------------------------------------------------------------------- */
1184
1185 #ifdef DEBUG
1186
1187 // Useful for finding partially full blocks in gdb
1188 void findSlop(bdescr *bd);
1189 void findSlop(bdescr *bd)
1190 {
1191 lnat slop;
1192
1193 for (; bd != NULL; bd = bd->link) {
1194 slop = (bd->blocks * BLOCK_SIZE_W) - (bd->free - bd->start);
1195 if (slop > (1024/sizeof(W_))) {
1196 debugBelch("block at %p (bdescr %p) has %ldKB slop\n",
1197 bd->start, bd, slop / (1024/sizeof(W_)));
1198 }
1199 }
1200 }
1201
1202 nat
1203 countBlocks(bdescr *bd)
1204 {
1205 nat n;
1206 for (n=0; bd != NULL; bd=bd->link) {
1207 n += bd->blocks;
1208 }
1209 return n;
1210 }
1211
1212 // (*1) Just like countBlocks, except that we adjust the count for a
1213 // megablock group so that it doesn't include the extra few blocks
1214 // that would be taken up by block descriptors in the second and
1215 // subsequent megablock. This is so we can tally the count with the
1216 // number of blocks allocated in the system, for memInventory().
1217 static nat
1218 countAllocdBlocks(bdescr *bd)
1219 {
1220 nat n;
1221 for (n=0; bd != NULL; bd=bd->link) {
1222 n += bd->blocks;
1223 // hack for megablock groups: see (*1) above
1224 if (bd->blocks > BLOCKS_PER_MBLOCK) {
1225 n -= (MBLOCK_SIZE / BLOCK_SIZE - BLOCKS_PER_MBLOCK)
1226 * (bd->blocks/(MBLOCK_SIZE/BLOCK_SIZE));
1227 }
1228 }
1229 return n;
1230 }
1231
1232 static lnat
1233 stepBlocks (step *stp)
1234 {
1235 ASSERT(countBlocks(stp->blocks) == stp->n_blocks);
1236 ASSERT(countBlocks(stp->large_objects) == stp->n_large_blocks);
1237 return stp->n_blocks + stp->n_old_blocks +
1238 countAllocdBlocks(stp->large_objects);
1239 }
1240
1241 // If memInventory() calculates that we have a memory leak, this
1242 // function will try to find the block(s) that are leaking by marking
1243 // all the ones that we know about, and search through memory to find
1244 // blocks that are not marked. In the debugger this can help to give
1245 // us a clue about what kind of block leaked. In the future we might
1246 // annotate blocks with their allocation site to give more helpful
1247 // info.
1248 static void
1249 findMemoryLeak (void)
1250 {
1251 nat g, s, i;
1252 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
1253 for (i = 0; i < n_capabilities; i++) {
1254 markBlocks(capabilities[i].mut_lists[g]);
1255 }
1256 markBlocks(generations[g].mut_list);
1257 for (s = 0; s < generations[g].n_steps; s++) {
1258 markBlocks(generations[g].steps[s].blocks);
1259 markBlocks(generations[g].steps[s].large_objects);
1260 }
1261 }
1262
1263 for (i = 0; i < n_nurseries; i++) {
1264 markBlocks(nurseries[i].blocks);
1265 markBlocks(nurseries[i].large_objects);
1266 }
1267
1268 #ifdef PROFILING
1269 // TODO:
1270 // if (RtsFlags.ProfFlags.doHeapProfile == HEAP_BY_RETAINER) {
1271 // markRetainerBlocks();
1272 // }
1273 #endif
1274
1275 // count the blocks allocated by the arena allocator
1276 // TODO:
1277 // markArenaBlocks();
1278
1279 // count the blocks containing executable memory
1280 markBlocks(exec_block);
1281
1282 reportUnmarkedBlocks();
1283 }
1284
1285
1286 void
1287 memInventory (rtsBool show)
1288 {
1289 nat g, s, i;
1290 step *stp;
1291 lnat gen_blocks[RtsFlags.GcFlags.generations];
1292 lnat nursery_blocks, retainer_blocks,
1293 arena_blocks, exec_blocks;
1294 lnat live_blocks = 0, free_blocks = 0;
1295 rtsBool leak;
1296
1297 // count the blocks we current have
1298
1299 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
1300 gen_blocks[g] = 0;
1301 for (i = 0; i < n_capabilities; i++) {
1302 gen_blocks[g] += countBlocks(capabilities[i].mut_lists[g]);
1303 }
1304 gen_blocks[g] += countAllocdBlocks(generations[g].mut_list);
1305 for (s = 0; s < generations[g].n_steps; s++) {
1306 stp = &generations[g].steps[s];
1307 gen_blocks[g] += stepBlocks(stp);
1308 }
1309 }
1310
1311 nursery_blocks = 0;
1312 for (i = 0; i < n_nurseries; i++) {
1313 nursery_blocks += stepBlocks(&nurseries[i]);
1314 }
1315
1316 retainer_blocks = 0;
1317 #ifdef PROFILING
1318 if (RtsFlags.ProfFlags.doHeapProfile == HEAP_BY_RETAINER) {
1319 retainer_blocks = retainerStackBlocks();
1320 }
1321 #endif
1322
1323 // count the blocks allocated by the arena allocator
1324 arena_blocks = arenaBlocks();
1325
1326 // count the blocks containing executable memory
1327 exec_blocks = countAllocdBlocks(exec_block);
1328
1329 /* count the blocks on the free list */
1330 free_blocks = countFreeList();
1331
1332 live_blocks = 0;
1333 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
1334 live_blocks += gen_blocks[g];
1335 }
1336 live_blocks += nursery_blocks +
1337 + retainer_blocks + arena_blocks + exec_blocks;
1338
1339 #define MB(n) (((n) * BLOCK_SIZE_W) / ((1024*1024)/sizeof(W_)))
1340
1341 leak = live_blocks + free_blocks != mblocks_allocated * BLOCKS_PER_MBLOCK;
1342
1343 if (show || leak)
1344 {
1345 if (leak) {
1346 debugBelch("Memory leak detected:\n");
1347 } else {
1348 debugBelch("Memory inventory:\n");
1349 }
1350 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
1351 debugBelch(" gen %d blocks : %5lu blocks (%lu MB)\n", g,
1352 gen_blocks[g], MB(gen_blocks[g]));
1353 }
1354 debugBelch(" nursery : %5lu blocks (%lu MB)\n",
1355 nursery_blocks, MB(nursery_blocks));
1356 debugBelch(" retainer : %5lu blocks (%lu MB)\n",
1357 retainer_blocks, MB(retainer_blocks));
1358 debugBelch(" arena blocks : %5lu blocks (%lu MB)\n",
1359 arena_blocks, MB(arena_blocks));
1360 debugBelch(" exec : %5lu blocks (%lu MB)\n",
1361 exec_blocks, MB(exec_blocks));
1362 debugBelch(" free : %5lu blocks (%lu MB)\n",
1363 free_blocks, MB(free_blocks));
1364 debugBelch(" total : %5lu blocks (%lu MB)\n",
1365 live_blocks + free_blocks, MB(live_blocks+free_blocks));
1366 if (leak) {
1367 debugBelch("\n in system : %5lu blocks (%lu MB)\n",
1368 mblocks_allocated * BLOCKS_PER_MBLOCK, mblocks_allocated);
1369 }
1370 }
1371
1372 if (leak) {
1373 debugBelch("\n");
1374 findMemoryLeak();
1375 }
1376 ASSERT(n_alloc_blocks == live_blocks);
1377 ASSERT(!leak);
1378 }
1379
1380
1381 /* Full heap sanity check. */
1382 void
1383 checkSanity( void )
1384 {
1385 nat g, s;
1386
1387 if (RtsFlags.GcFlags.generations == 1) {
1388 checkHeap(g0s0->blocks);
1389 checkLargeObjects(g0s0->large_objects);
1390 } else {
1391
1392 for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
1393 for (s = 0; s < generations[g].n_steps; s++) {
1394 if (g == 0 && s == 0) { continue; }
1395 ASSERT(countBlocks(generations[g].steps[s].blocks)
1396 == generations[g].steps[s].n_blocks);
1397 ASSERT(countBlocks(generations[g].steps[s].large_objects)
1398 == generations[g].steps[s].n_large_blocks);
1399 checkHeap(generations[g].steps[s].blocks);
1400 checkLargeObjects(generations[g].steps[s].large_objects);
1401 }
1402 }
1403
1404 for (s = 0; s < n_nurseries; s++) {
1405 ASSERT(countBlocks(nurseries[s].blocks)
1406 == nurseries[s].n_blocks);
1407 ASSERT(countBlocks(nurseries[s].large_objects)
1408 == nurseries[s].n_large_blocks);
1409 }
1410
1411 checkFreeListSanity();
1412 }
1413
1414 #if defined(THREADED_RTS)
1415 // check the stacks too in threaded mode, because we don't do a
1416 // full heap sanity check in this case (see checkHeap())
1417 checkMutableLists(rtsTrue);
1418 #else
1419 checkMutableLists(rtsFalse);
1420 #endif
1421 }
1422
1423 /* Nursery sanity check */
1424 void
1425 checkNurserySanity( step *stp )
1426 {
1427 bdescr *bd, *prev;
1428 nat blocks = 0;
1429
1430 prev = NULL;
1431 for (bd = stp->blocks; bd != NULL; bd = bd->link) {
1432 ASSERT(bd->u.back == prev);
1433 prev = bd;
1434 blocks += bd->blocks;
1435 }
1436 ASSERT(blocks == stp->n_blocks);
1437 }
1438
1439 // handy function for use in gdb, because Bdescr() is inlined.
1440 extern bdescr *_bdescr( StgPtr p );
1441
1442 bdescr *
1443 _bdescr( StgPtr p )
1444 {
1445 return Bdescr(p);
1446 }
1447
1448 #endif