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
57 int is_compacted; // compact this step? (old gen only)
59 struct generation_ * gen; // generation this step belongs to
60 unsigned int gen_no; // generation number (cached)
62 bdescr * blocks; // blocks in this step
63 unsigned int n_blocks; // number of blocks
65 struct step_ * to; // destination step for live objects
67 bdescr * large_objects; // large objects (doubly linked)
68 unsigned int n_large_blocks; // no. of blocks used by large objs
70 // ------------------------------------
71 // Fields below are used during GC only
73 // During GC, if we are collecting this step, blocks and n_blocks
74 // are copied into the following two fields. After GC, these blocks
76 bdescr * old_blocks; // bdescr of first from-space block
77 unsigned int n_old_blocks; // number of blocks in from-space
79 bdescr * todos; // blocks waiting to be scavenged
80 unsigned int n_todos; // count of above
82 #if defined(THREADED_RTS)
83 SpinLock sync_todo; // lock for todos
84 SpinLock sync_large_objects; // lock for large_objects
85 // and scavenged_large_objects
88 bdescr * scavenged_large_objects; // live large objs after GC (d-link)
89 unsigned int n_scavenged_large_blocks; // size (not count) of above
91 bdescr * bitmap; // bitmap for compacting collection
95 typedef struct generation_ {
96 unsigned int no; // generation number
97 step * steps; // steps
98 unsigned int n_steps; // number of steps
99 unsigned int max_blocks; // max blocks in step 0
100 bdescr *mut_list; // mut objects in this gen (not G0)
103 unsigned int collections;
104 unsigned int failed_promotions;
106 // temporary use during GC:
107 bdescr *saved_mut_list;
110 extern generation * RTS_VAR(generations);
112 extern generation * RTS_VAR(g0);
113 extern step * RTS_VAR(g0s0);
114 extern generation * RTS_VAR(oldest_gen);
116 /* -----------------------------------------------------------------------------
117 Initialisation / De-initialisation
118 -------------------------------------------------------------------------- */
120 extern void initStorage(void);
121 extern void exitStorage(void);
122 extern void freeStorage(void);
124 /* -----------------------------------------------------------------------------
127 StgPtr allocateInGen(generation *g, nat n)
128 Allocates a chunk of contiguous store
129 n words long in generation g,
130 returning a pointer to the first word.
133 StgPtr allocate(nat n) Equaivalent to allocateInGen(g0)
135 StgPtr allocateLocal(Capability *cap, nat n)
136 Allocates memory from the nursery in
137 the current Capability. This can be
138 done without taking a global lock,
141 StgPtr allocatePinned(nat n) Allocates a chunk of contiguous store
142 n words long, which is at a fixed
143 address (won't be moved by GC).
144 Returns a pointer to the first word.
147 NOTE: the GC can't in general handle
148 pinned objects, so allocatePinned()
149 can only be used for ByteArrays at the
152 Don't forget to TICK_ALLOC_XXX(...)
153 after calling allocate or
154 allocatePinned, for the
155 benefit of the ticky-ticky profiler.
157 rtsBool doYouWantToGC(void) Returns True if the storage manager is
158 ready to perform a GC, False otherwise.
160 lnat allocatedBytes(void) Returns the number of bytes allocated
161 via allocate() since the last GC.
162 Used in the reporting of statistics.
164 -------------------------------------------------------------------------- */
166 extern StgPtr allocate ( nat n );
167 extern StgPtr allocateInGen ( generation *g, nat n );
168 extern StgPtr allocateLocal ( Capability *cap, nat n );
169 extern StgPtr allocatePinned ( nat n );
170 extern lnat allocatedBytes ( void );
172 extern bdescr * RTS_VAR(small_alloc_list);
173 extern bdescr * RTS_VAR(large_alloc_list);
174 extern bdescr * RTS_VAR(pinned_object_block);
176 extern nat RTS_VAR(alloc_blocks);
177 extern nat RTS_VAR(alloc_blocks_lim);
179 INLINE_HEADER rtsBool
180 doYouWantToGC( void )
182 return (alloc_blocks >= alloc_blocks_lim);
185 /* memory allocator for executable memory */
186 extern void *allocateExec (nat bytes);
187 extern void freeExec (void *p);
189 /* -----------------------------------------------------------------------------
190 Performing Garbage Collection
192 GarbageCollect(get_roots) Performs a garbage collection.
193 'get_roots' is called to find all the
194 roots that the system knows about.
197 -------------------------------------------------------------------------- */
199 extern void GarbageCollect(rtsBool force_major_gc);
201 /* -----------------------------------------------------------------------------
202 Generational garbage collection support
204 recordMutable(StgPtr p) Informs the garbage collector that a
205 previously immutable object has
206 become (permanently) mutable. Used
207 by thawArray and similar.
209 updateWithIndirection(p1,p2) Updates the object at p1 with an
210 indirection pointing to p2. This is
211 normally called for objects in an old
212 generation (>0) when they are updated.
214 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
216 -------------------------------------------------------------------------- */
219 * Storage manager mutex
221 #if defined(THREADED_RTS)
222 extern Mutex sm_mutex;
223 extern Mutex atomic_modify_mutvar_mutex;
224 extern SpinLock recordMutableGen_sync;
227 #if defined(THREADED_RTS)
228 #define ACQUIRE_SM_LOCK ACQUIRE_LOCK(&sm_mutex);
229 #define RELEASE_SM_LOCK RELEASE_LOCK(&sm_mutex);
230 #define ASSERT_SM_LOCK() ASSERT_LOCK_HELD(&sm_mutex);
232 #define ACQUIRE_SM_LOCK
233 #define RELEASE_SM_LOCK
234 #define ASSERT_SM_LOCK()
238 recordMutableGen(StgClosure *p, generation *gen)
243 if (bd->free >= bd->start + BLOCK_SIZE_W) {
245 new_bd = allocBlock();
250 *bd->free++ = (StgWord)p;
255 recordMutableGenLock(StgClosure *p, generation *gen)
258 recordMutableGen(p,gen);
263 recordMutableGen_GC(StgClosure *p, generation *gen)
265 ACQUIRE_SPIN_LOCK(&recordMutableGen_sync);
266 recordMutableGen(p,gen);
267 RELEASE_SPIN_LOCK(&recordMutableGen_sync);
271 recordMutable(StgClosure *p)
274 ASSERT(closure_MUTABLE(p));
276 if (bd->gen_no > 0) recordMutableGen(p, &RTS_DEREF(generations)[bd->gen_no]);
280 recordMutableLock(StgClosure *p)
287 /* -----------------------------------------------------------------------------
288 The CAF table - used to let us revert CAFs in GHCi
289 -------------------------------------------------------------------------- */
291 /* set to disable CAF garbage collection in GHCi. */
292 /* (needed when dynamic libraries are used). */
293 extern rtsBool keepCAFs;
295 /* -----------------------------------------------------------------------------
296 This is the write barrier for MUT_VARs, a.k.a. IORefs. A
297 MUT_VAR_CLEAN object is not on the mutable list; a MUT_VAR_DIRTY
298 is. When written to, a MUT_VAR_CLEAN turns into a MUT_VAR_DIRTY
299 and is put on the mutable list.
300 -------------------------------------------------------------------------- */
302 void dirty_MUT_VAR(StgRegTable *reg, StgClosure *p);
304 /* -----------------------------------------------------------------------------
305 DEBUGGING predicates for pointers
307 LOOKS_LIKE_INFO_PTR(p) returns False if p is definitely not an info ptr
308 LOOKS_LIKE_CLOSURE_PTR(p) returns False if p is definitely not a closure ptr
310 These macros are complete but not sound. That is, they might
311 return false positives. Do not rely on them to distinguish info
312 pointers from closure pointers, for example.
314 We don't use address-space predicates these days, for portability
315 reasons, and the fact that code/data can be scattered about the
316 address space in a dynamically-linked environment. Our best option
317 is to look at the alleged info table and see whether it seems to
319 -------------------------------------------------------------------------- */
321 #define LOOKS_LIKE_INFO_PTR(p) \
322 (p && LOOKS_LIKE_INFO_PTR_NOT_NULL(p))
324 #define LOOKS_LIKE_INFO_PTR_NOT_NULL(p) \
325 (((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type != INVALID_OBJECT && \
326 ((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type < N_CLOSURE_TYPES)
328 #define LOOKS_LIKE_CLOSURE_PTR(p) \
329 (LOOKS_LIKE_INFO_PTR((UNTAG_CLOSURE((StgClosure *)(p)))->header.info))
331 /* -----------------------------------------------------------------------------
332 Macros for calculating how big a closure will be (used during allocation)
333 -------------------------------------------------------------------------- */
335 INLINE_HEADER StgOffset PAP_sizeW ( nat n_args )
336 { return sizeofW(StgPAP) + n_args; }
338 INLINE_HEADER StgOffset AP_sizeW ( nat n_args )
339 { return sizeofW(StgAP) + n_args; }
341 INLINE_HEADER StgOffset AP_STACK_sizeW ( nat size )
342 { return sizeofW(StgAP_STACK) + size; }
344 INLINE_HEADER StgOffset CONSTR_sizeW( nat p, nat np )
345 { return sizeofW(StgHeader) + p + np; }
347 INLINE_HEADER StgOffset THUNK_SELECTOR_sizeW ( void )
348 { return sizeofW(StgSelector); }
350 INLINE_HEADER StgOffset BLACKHOLE_sizeW ( void )
351 { return sizeofW(StgHeader)+MIN_PAYLOAD_SIZE; }
353 /* --------------------------------------------------------------------------
355 ------------------------------------------------------------------------*/
357 INLINE_HEADER StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
358 { return sizeofW(StgClosure)
359 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
360 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
362 INLINE_HEADER StgOffset thunk_sizeW_fromITBL( const StgInfoTable* itbl )
363 { return sizeofW(StgThunk)
364 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
365 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
367 INLINE_HEADER StgOffset ap_stack_sizeW( StgAP_STACK* x )
368 { return AP_STACK_sizeW(x->size); }
370 INLINE_HEADER StgOffset ap_sizeW( StgAP* x )
371 { return AP_sizeW(x->n_args); }
373 INLINE_HEADER StgOffset pap_sizeW( StgPAP* x )
374 { return PAP_sizeW(x->n_args); }
376 INLINE_HEADER StgOffset arr_words_sizeW( StgArrWords* x )
377 { return sizeofW(StgArrWords) + x->words; }
379 INLINE_HEADER StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
380 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
382 INLINE_HEADER StgWord tso_sizeW ( StgTSO *tso )
383 { return TSO_STRUCT_SIZEW + tso->stack_size; }
385 INLINE_HEADER StgWord bco_sizeW ( StgBCO *bco )
386 { return bco->size; }
389 closure_sizeW_ (StgClosure *p, StgInfoTable *info)
391 switch (info->type) {
394 return sizeofW(StgThunk) + 1;
399 return sizeofW(StgHeader) + 1;
403 return sizeofW(StgThunk) + 2;
410 return sizeofW(StgHeader) + 2;
412 return thunk_sizeW_fromITBL(info);
414 return THUNK_SELECTOR_sizeW();
416 return ap_stack_sizeW((StgAP_STACK *)p);
418 return ap_sizeW((StgAP *)p);
420 return pap_sizeW((StgPAP *)p);
424 case IND_OLDGEN_PERM:
425 return sizeofW(StgInd);
427 return arr_words_sizeW((StgArrWords *)p);
428 case MUT_ARR_PTRS_CLEAN:
429 case MUT_ARR_PTRS_DIRTY:
430 case MUT_ARR_PTRS_FROZEN:
431 case MUT_ARR_PTRS_FROZEN0:
432 return mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
434 return tso_sizeW((StgTSO *)p);
436 return bco_sizeW((StgBCO *)p);
437 case TVAR_WATCH_QUEUE:
438 return sizeofW(StgTVarWatchQueue);
440 return sizeofW(StgTVar);
442 return sizeofW(StgTRecChunk);
444 return sizeofW(StgTRecHeader);
445 case ATOMIC_INVARIANT:
446 return sizeofW(StgAtomicInvariant);
447 case INVARIANT_CHECK_QUEUE:
448 return sizeofW(StgInvariantCheckQueue);
450 return sizeW_fromITBL(info);
454 // The definitive way to find the size, in words, of a heap-allocated closure
456 closure_sizeW (StgClosure *p)
458 return closure_sizeW_(p, get_itbl(p));
461 /* -----------------------------------------------------------------------------
462 Sizes of stack frames
463 -------------------------------------------------------------------------- */
465 INLINE_HEADER StgWord stack_frame_sizeW( StgClosure *frame )
467 StgRetInfoTable *info;
469 info = get_ret_itbl(frame);
470 switch (info->i.type) {
474 StgRetDyn *dyn = (StgRetDyn *)frame;
475 return sizeofW(StgRetDyn) + RET_DYN_BITMAP_SIZE +
476 RET_DYN_NONPTR_REGS_SIZE +
477 RET_DYN_PTRS(dyn->liveness) + RET_DYN_NONPTRS(dyn->liveness);
481 return sizeofW(StgRetFun) + ((StgRetFun *)frame)->size;
484 return 1 + GET_LARGE_BITMAP(&info->i)->size;
487 return 2 + BCO_BITMAP_SIZE((StgBCO *)((P_)frame)[1]);
490 return 1 + BITMAP_SIZE(info->i.layout.bitmap);
494 /* -----------------------------------------------------------------------------
496 -------------------------------------------------------------------------- */
498 extern void allocNurseries ( void );
499 extern void resetNurseries ( void );
500 extern void resizeNurseries ( nat blocks );
501 extern void resizeNurseriesFixed ( nat blocks );
502 extern lnat countNurseryBlocks ( void );
504 /* -----------------------------------------------------------------------------
506 -------------------------------------------------------------------------- */
508 typedef void (*evac_fn)(StgClosure **);
510 extern void threadPaused ( Capability *cap, StgTSO * );
511 extern StgClosure * isAlive ( StgClosure *p );
512 extern void markCAFs ( evac_fn evac );
513 extern void GetRoots ( evac_fn evac );
515 /* -----------------------------------------------------------------------------
516 Stats 'n' DEBUG stuff
517 -------------------------------------------------------------------------- */
519 extern ullong RTS_VAR(total_allocated);
521 extern lnat calcAllocated ( void );
522 extern lnat calcLiveBlocks ( void );
523 extern lnat calcLiveWords ( void );
524 extern lnat countOccupied ( bdescr *bd );
525 extern lnat calcNeeded ( void );
528 extern void memInventory(void);
529 extern void checkSanity(void);
530 extern nat countBlocks(bdescr *);
531 extern void checkNurserySanity( step *stp );
535 void printMutOnceList(generation *gen);
536 void printMutableList(generation *gen);
539 /* ----------------------------------------------------------------------------
540 Storage manager internal APIs and globals
541 ------------------------------------------------------------------------- */
543 #define END_OF_STATIC_LIST stgCast(StgClosure*,1)
545 extern void newDynCAF(StgClosure *);
547 extern void move_TSO(StgTSO *src, StgTSO *dest);
548 extern StgTSO *relocate_stack(StgTSO *dest, ptrdiff_t diff);
550 extern StgClosure * RTS_VAR(scavenged_static_objects);
551 extern StgWeak * RTS_VAR(old_weak_ptr_list);
552 extern StgWeak * RTS_VAR(weak_ptr_list);
553 extern StgClosure * RTS_VAR(caf_list);
554 extern StgClosure * RTS_VAR(revertible_caf_list);
555 extern StgTSO * RTS_VAR(resurrected_threads);
557 #endif /* STORAGE_H */