1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
5 * External Storage Manger Interface
7 * ---------------------------------------------------------------------------*/
13 #include "OSThreads.h"
16 /* -----------------------------------------------------------------------------
19 * We support an arbitrary number of generations, with an arbitrary number
20 * of steps per generation. Notes (in no particular order):
22 * - all generations except the oldest should have two steps. This gives
23 * objects a decent chance to age before being promoted, and in
24 * particular will ensure that we don't end up with too many
25 * thunks being updated in older generations.
27 * - the oldest generation has one step. There's no point in aging
28 * objects in the oldest generation.
30 * - generation 0, step 0 (G0S0) is the allocation area. It is given
31 * a fixed set of blocks during initialisation, and these blocks
34 * - during garbage collection, each step which is an evacuation
35 * destination (i.e. all steps except G0S0) is allocated a to-space.
36 * evacuated objects are allocated into the step's to-space until
37 * GC is finished, when the original step's contents may be freed
38 * and replaced by the to-space.
40 * - the mutable-list is per-generation (not per-step). G0 doesn't
41 * have one (since every garbage collection collects at least G0).
43 * - block descriptors contain pointers to both the step and the
44 * generation that the block belongs to, for convenience.
46 * - static objects are stored in per-generation lists. See GC.c for
47 * details of how we collect CAFs in the generational scheme.
49 * - large objects are per-step, and are promoted in the same way
50 * as small objects, except that we may allocate large objects into
51 * generation 1 initially.
53 * ------------------------------------------------------------------------- */
55 typedef struct step_ {
56 unsigned int no; // step number in this generation
57 unsigned int abs_no; // absolute step number
58 int is_compacted; // compact this step? (old gen only)
60 struct generation_ * gen; // generation this step belongs to
61 unsigned int gen_no; // generation number (cached)
63 bdescr * blocks; // blocks in this step
64 unsigned int n_blocks; // number of blocks
65 unsigned int n_words; // number of words
67 struct step_ * to; // destination step for live objects
69 bdescr * large_objects; // large objects (doubly linked)
70 unsigned int n_large_blocks; // no. of blocks used by large objs
73 // ------------------------------------
74 // Fields below are used during GC only
76 // During GC, if we are collecting this step, blocks and n_blocks
77 // are copied into the following two fields. After GC, these blocks
80 #if defined(THREADED_RTS)
81 char pad[128]; // make sure the following is
82 // on a separate cache line.
83 SpinLock sync_todo; // lock for todos
84 SpinLock sync_large_objects; // lock for large_objects
85 // and scavenged_large_objects
88 bdescr * old_blocks; // bdescr of first from-space block
89 unsigned int n_old_blocks; // number of blocks in from-space
91 bdescr * todos; // blocks waiting to be scavenged
93 unsigned int n_todos; // count of above
95 bdescr * part_blocks; // partially-full scanned blocks
96 unsigned int n_part_blocks; // count of above
98 bdescr * scavenged_large_objects; // live large objs after GC (d-link)
99 unsigned int n_scavenged_large_blocks; // size (not count) of above
101 bdescr * bitmap; // bitmap for compacting collection
107 typedef struct generation_ {
108 unsigned int no; // generation number
109 step * steps; // steps
110 unsigned int n_steps; // number of steps
111 unsigned int max_blocks; // max blocks in step 0
112 bdescr *mut_list; // mut objects in this gen (not G0)
115 unsigned int collections;
116 unsigned int failed_promotions;
118 // temporary use during GC:
119 bdescr *saved_mut_list;
122 extern generation * RTS_VAR(generations);
124 extern generation * RTS_VAR(g0);
125 extern step * RTS_VAR(g0s0);
126 extern generation * RTS_VAR(oldest_gen);
127 extern step * RTS_VAR(all_steps);
128 extern nat RTS_VAR(total_steps);
130 /* -----------------------------------------------------------------------------
131 Initialisation / De-initialisation
132 -------------------------------------------------------------------------- */
134 extern void initStorage(void);
135 extern void exitStorage(void);
136 extern void freeStorage(void);
138 /* -----------------------------------------------------------------------------
141 StgPtr allocateInGen(generation *g, nat n)
142 Allocates a chunk of contiguous store
143 n words long in generation g,
144 returning a pointer to the first word.
147 StgPtr allocate(nat n) Equaivalent to allocateInGen(g0)
149 StgPtr allocateLocal(Capability *cap, nat n)
150 Allocates memory from the nursery in
151 the current Capability. This can be
152 done without taking a global lock,
155 StgPtr allocatePinned(nat n) Allocates a chunk of contiguous store
156 n words long, which is at a fixed
157 address (won't be moved by GC).
158 Returns a pointer to the first word.
161 NOTE: the GC can't in general handle
162 pinned objects, so allocatePinned()
163 can only be used for ByteArrays at the
166 Don't forget to TICK_ALLOC_XXX(...)
167 after calling allocate or
168 allocatePinned, for the
169 benefit of the ticky-ticky profiler.
171 rtsBool doYouWantToGC(void) Returns True if the storage manager is
172 ready to perform a GC, False otherwise.
174 lnat allocatedBytes(void) Returns the number of bytes allocated
175 via allocate() since the last GC.
176 Used in the reporting of statistics.
178 -------------------------------------------------------------------------- */
180 extern StgPtr allocate ( nat n );
181 extern StgPtr allocateInGen ( generation *g, nat n );
182 extern StgPtr allocateLocal ( Capability *cap, nat n );
183 extern StgPtr allocatePinned ( nat n );
184 extern lnat allocatedBytes ( void );
186 extern bdescr * RTS_VAR(small_alloc_list);
187 extern bdescr * RTS_VAR(large_alloc_list);
188 extern bdescr * RTS_VAR(pinned_object_block);
190 extern nat RTS_VAR(alloc_blocks);
191 extern nat RTS_VAR(alloc_blocks_lim);
193 INLINE_HEADER rtsBool
194 doYouWantToGC( void )
196 return (alloc_blocks >= alloc_blocks_lim);
199 /* memory allocator for executable memory */
200 extern void *allocateExec (nat bytes);
201 extern void freeExec (void *p);
203 /* for splitting blocks groups in two */
204 extern bdescr * splitLargeBlock (bdescr *bd, nat blocks);
206 /* -----------------------------------------------------------------------------
207 Performing Garbage Collection
209 GarbageCollect(get_roots) Performs a garbage collection.
210 'get_roots' is called to find all the
211 roots that the system knows about.
214 -------------------------------------------------------------------------- */
216 extern void GarbageCollect(rtsBool force_major_gc);
218 /* -----------------------------------------------------------------------------
219 Generational garbage collection support
221 recordMutable(StgPtr p) Informs the garbage collector that a
222 previously immutable object has
223 become (permanently) mutable. Used
224 by thawArray and similar.
226 updateWithIndirection(p1,p2) Updates the object at p1 with an
227 indirection pointing to p2. This is
228 normally called for objects in an old
229 generation (>0) when they are updated.
231 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
233 -------------------------------------------------------------------------- */
236 * Storage manager mutex
238 #if defined(THREADED_RTS)
239 extern Mutex sm_mutex;
240 extern Mutex atomic_modify_mutvar_mutex;
241 extern SpinLock recordMutableGen_sync;
244 #if defined(THREADED_RTS)
245 #define ACQUIRE_SM_LOCK ACQUIRE_LOCK(&sm_mutex);
246 #define RELEASE_SM_LOCK RELEASE_LOCK(&sm_mutex);
247 #define ASSERT_SM_LOCK() ASSERT_LOCK_HELD(&sm_mutex);
249 #define ACQUIRE_SM_LOCK
250 #define RELEASE_SM_LOCK
251 #define ASSERT_SM_LOCK()
255 recordMutableGen(StgClosure *p, generation *gen)
260 if (bd->free >= bd->start + BLOCK_SIZE_W) {
262 new_bd = allocBlock();
267 *bd->free++ = (StgWord)p;
272 recordMutableGenLock(StgClosure *p, generation *gen)
275 recordMutableGen(p,gen);
279 extern bdescr *allocBlock_sync(void);
281 // Version of recordMutableGen() for use in parallel GC. The same as
282 // recordMutableGen(), except that we surround it with a spinlock and
283 // call the spinlock version of allocBlock().
285 recordMutableGen_GC(StgClosure *p, generation *gen)
289 ACQUIRE_SPIN_LOCK(&recordMutableGen_sync);
292 if (bd->free >= bd->start + BLOCK_SIZE_W) {
294 new_bd = allocBlock_sync();
299 *bd->free++ = (StgWord)p;
301 RELEASE_SPIN_LOCK(&recordMutableGen_sync);
305 recordMutable(StgClosure *p)
308 ASSERT(closure_MUTABLE(p));
310 if (bd->gen_no > 0) recordMutableGen(p, &RTS_DEREF(generations)[bd->gen_no]);
314 recordMutableLock(StgClosure *p)
321 /* -----------------------------------------------------------------------------
322 The CAF table - used to let us revert CAFs in GHCi
323 -------------------------------------------------------------------------- */
325 /* set to disable CAF garbage collection in GHCi. */
326 /* (needed when dynamic libraries are used). */
327 extern rtsBool keepCAFs;
329 /* -----------------------------------------------------------------------------
330 This is the write barrier for MUT_VARs, a.k.a. IORefs. A
331 MUT_VAR_CLEAN object is not on the mutable list; a MUT_VAR_DIRTY
332 is. When written to, a MUT_VAR_CLEAN turns into a MUT_VAR_DIRTY
333 and is put on the mutable list.
334 -------------------------------------------------------------------------- */
336 void dirty_MUT_VAR(StgRegTable *reg, StgClosure *p);
338 /* -----------------------------------------------------------------------------
339 DEBUGGING predicates for pointers
341 LOOKS_LIKE_INFO_PTR(p) returns False if p is definitely not an info ptr
342 LOOKS_LIKE_CLOSURE_PTR(p) returns False if p is definitely not a closure ptr
344 These macros are complete but not sound. That is, they might
345 return false positives. Do not rely on them to distinguish info
346 pointers from closure pointers, for example.
348 We don't use address-space predicates these days, for portability
349 reasons, and the fact that code/data can be scattered about the
350 address space in a dynamically-linked environment. Our best option
351 is to look at the alleged info table and see whether it seems to
353 -------------------------------------------------------------------------- */
355 #define LOOKS_LIKE_INFO_PTR(p) \
356 (p && LOOKS_LIKE_INFO_PTR_NOT_NULL(p))
358 #define LOOKS_LIKE_INFO_PTR_NOT_NULL(p) \
359 (((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type != INVALID_OBJECT && \
360 ((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type < N_CLOSURE_TYPES)
362 #define LOOKS_LIKE_CLOSURE_PTR(p) \
363 (LOOKS_LIKE_INFO_PTR((UNTAG_CLOSURE((StgClosure *)(p)))->header.info))
365 /* -----------------------------------------------------------------------------
366 Macros for calculating how big a closure will be (used during allocation)
367 -------------------------------------------------------------------------- */
369 INLINE_HEADER StgOffset PAP_sizeW ( nat n_args )
370 { return sizeofW(StgPAP) + n_args; }
372 INLINE_HEADER StgOffset AP_sizeW ( nat n_args )
373 { return sizeofW(StgAP) + n_args; }
375 INLINE_HEADER StgOffset AP_STACK_sizeW ( nat size )
376 { return sizeofW(StgAP_STACK) + size; }
378 INLINE_HEADER StgOffset CONSTR_sizeW( nat p, nat np )
379 { return sizeofW(StgHeader) + p + np; }
381 INLINE_HEADER StgOffset THUNK_SELECTOR_sizeW ( void )
382 { return sizeofW(StgSelector); }
384 INLINE_HEADER StgOffset BLACKHOLE_sizeW ( void )
385 { return sizeofW(StgHeader)+MIN_PAYLOAD_SIZE; }
387 /* --------------------------------------------------------------------------
389 ------------------------------------------------------------------------*/
391 INLINE_HEADER StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
392 { return sizeofW(StgClosure)
393 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
394 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
396 INLINE_HEADER StgOffset thunk_sizeW_fromITBL( const StgInfoTable* itbl )
397 { return sizeofW(StgThunk)
398 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
399 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
401 INLINE_HEADER StgOffset ap_stack_sizeW( StgAP_STACK* x )
402 { return AP_STACK_sizeW(x->size); }
404 INLINE_HEADER StgOffset ap_sizeW( StgAP* x )
405 { return AP_sizeW(x->n_args); }
407 INLINE_HEADER StgOffset pap_sizeW( StgPAP* x )
408 { return PAP_sizeW(x->n_args); }
410 INLINE_HEADER StgOffset arr_words_sizeW( StgArrWords* x )
411 { return sizeofW(StgArrWords) + x->words; }
413 INLINE_HEADER StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
414 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
416 INLINE_HEADER StgWord tso_sizeW ( StgTSO *tso )
417 { return TSO_STRUCT_SIZEW + tso->stack_size; }
419 INLINE_HEADER StgWord bco_sizeW ( StgBCO *bco )
420 { return bco->size; }
423 closure_sizeW_ (StgClosure *p, StgInfoTable *info)
425 switch (info->type) {
428 return sizeofW(StgThunk) + 1;
433 return sizeofW(StgHeader) + 1;
437 return sizeofW(StgThunk) + 2;
444 return sizeofW(StgHeader) + 2;
446 return thunk_sizeW_fromITBL(info);
448 return THUNK_SELECTOR_sizeW();
450 return ap_stack_sizeW((StgAP_STACK *)p);
452 return ap_sizeW((StgAP *)p);
454 return pap_sizeW((StgPAP *)p);
458 case IND_OLDGEN_PERM:
459 return sizeofW(StgInd);
461 return arr_words_sizeW((StgArrWords *)p);
462 case MUT_ARR_PTRS_CLEAN:
463 case MUT_ARR_PTRS_DIRTY:
464 case MUT_ARR_PTRS_FROZEN:
465 case MUT_ARR_PTRS_FROZEN0:
466 return mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
468 return tso_sizeW((StgTSO *)p);
470 return bco_sizeW((StgBCO *)p);
471 case TVAR_WATCH_QUEUE:
472 return sizeofW(StgTVarWatchQueue);
474 return sizeofW(StgTVar);
476 return sizeofW(StgTRecChunk);
478 return sizeofW(StgTRecHeader);
479 case ATOMIC_INVARIANT:
480 return sizeofW(StgAtomicInvariant);
481 case INVARIANT_CHECK_QUEUE:
482 return sizeofW(StgInvariantCheckQueue);
484 return sizeW_fromITBL(info);
488 // The definitive way to find the size, in words, of a heap-allocated closure
490 closure_sizeW (StgClosure *p)
492 return closure_sizeW_(p, get_itbl(p));
495 /* -----------------------------------------------------------------------------
496 Sizes of stack frames
497 -------------------------------------------------------------------------- */
499 INLINE_HEADER StgWord stack_frame_sizeW( StgClosure *frame )
501 StgRetInfoTable *info;
503 info = get_ret_itbl(frame);
504 switch (info->i.type) {
508 StgRetDyn *dyn = (StgRetDyn *)frame;
509 return sizeofW(StgRetDyn) + RET_DYN_BITMAP_SIZE +
510 RET_DYN_NONPTR_REGS_SIZE +
511 RET_DYN_PTRS(dyn->liveness) + RET_DYN_NONPTRS(dyn->liveness);
515 return sizeofW(StgRetFun) + ((StgRetFun *)frame)->size;
518 return 1 + GET_LARGE_BITMAP(&info->i)->size;
521 return 2 + BCO_BITMAP_SIZE((StgBCO *)((P_)frame)[1]);
524 return 1 + BITMAP_SIZE(info->i.layout.bitmap);
528 /* -----------------------------------------------------------------------------
530 -------------------------------------------------------------------------- */
532 extern void allocNurseries ( void );
533 extern void resetNurseries ( void );
534 extern void resizeNurseries ( nat blocks );
535 extern void resizeNurseriesFixed ( nat blocks );
536 extern lnat countNurseryBlocks ( void );
538 /* -----------------------------------------------------------------------------
540 -------------------------------------------------------------------------- */
542 typedef void (*evac_fn)(StgClosure **);
544 extern void threadPaused ( Capability *cap, StgTSO * );
545 extern StgClosure * isAlive ( StgClosure *p );
546 extern void markCAFs ( evac_fn evac );
547 extern void GetRoots ( evac_fn evac );
549 /* -----------------------------------------------------------------------------
550 Stats 'n' DEBUG stuff
551 -------------------------------------------------------------------------- */
553 extern ullong RTS_VAR(total_allocated);
555 extern lnat calcAllocated ( void );
556 extern lnat calcLiveBlocks ( void );
557 extern lnat calcLiveWords ( void );
558 extern lnat countOccupied ( bdescr *bd );
559 extern lnat calcNeeded ( void );
562 extern void memInventory(rtsBool show);
563 extern void checkSanity(void);
564 extern nat countBlocks(bdescr *);
565 extern void checkNurserySanity( step *stp );
569 void printMutOnceList(generation *gen);
570 void printMutableList(generation *gen);
573 /* ----------------------------------------------------------------------------
574 Storage manager internal APIs and globals
575 ------------------------------------------------------------------------- */
577 #define END_OF_STATIC_LIST stgCast(StgClosure*,1)
579 extern void newDynCAF(StgClosure *);
581 extern void move_TSO(StgTSO *src, StgTSO *dest);
582 extern StgTSO *relocate_stack(StgTSO *dest, ptrdiff_t diff);
584 extern StgWeak * RTS_VAR(old_weak_ptr_list);
585 extern StgWeak * RTS_VAR(weak_ptr_list);
586 extern StgClosure * RTS_VAR(caf_list);
587 extern StgClosure * RTS_VAR(revertible_caf_list);
588 extern StgTSO * RTS_VAR(resurrected_threads);
590 #endif /* STORAGE_H */