1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team, 1998-2004
5 * External Storage Manger Interface
7 * ---------------------------------------------------------------------------*/
13 #include "OSThreads.h"
15 /* -----------------------------------------------------------------------------
18 * We support an arbitrary number of generations, with an arbitrary number
19 * of steps per generation. Notes (in no particular order):
21 * - all generations except the oldest should have two steps. This gives
22 * objects a decent chance to age before being promoted, and in
23 * particular will ensure that we don't end up with too many
24 * thunks being updated in older generations.
26 * - the oldest generation has one step. There's no point in aging
27 * objects in the oldest generation.
29 * - generation 0, step 0 (G0S0) is the allocation area. It is given
30 * a fixed set of blocks during initialisation, and these blocks
33 * - during garbage collection, each step which is an evacuation
34 * destination (i.e. all steps except G0S0) is allocated a to-space.
35 * evacuated objects are allocated into the step's to-space until
36 * GC is finished, when the original step's contents may be freed
37 * and replaced by the to-space.
39 * - the mutable-list is per-generation (not per-step). G0 doesn't
40 * have one (since every garbage collection collects at least G0).
42 * - block descriptors contain pointers to both the step and the
43 * generation that the block belongs to, for convenience.
45 * - static objects are stored in per-generation lists. See GC.c for
46 * details of how we collect CAFs in the generational scheme.
48 * - large objects are per-step, and are promoted in the same way
49 * as small objects, except that we may allocate large objects into
50 * generation 1 initially.
52 * ------------------------------------------------------------------------- */
54 typedef struct step_ {
55 unsigned int no; /* step number */
56 bdescr * blocks; /* blocks in this step */
57 unsigned int n_blocks; /* number of blocks */
58 struct step_ * to; /* destination step for live objects */
59 struct generation_ * gen; /* generation this step belongs to */
60 unsigned int gen_no; /* generation number (cached) */
61 bdescr * large_objects; /* large objects (doubly linked) */
62 unsigned int n_large_blocks; /* no. of blocks used by large objs */
63 int is_compacted; /* compact this step? (old gen only) */
65 /* During GC, if we are collecting this step, blocks and n_blocks
66 * are copied into the following two fields. After GC, these blocks
68 bdescr * old_blocks; /* bdescr of first from-space block */
69 unsigned int n_old_blocks; /* number of blocks in from-space */
71 /* temporary use during GC: */
72 StgPtr hp; /* next free locn in to-space */
73 StgPtr hpLim; /* end of current to-space block */
74 bdescr * hp_bd; /* bdescr of current to-space block */
75 StgPtr scavd_hp; /* ... same as above, but already */
76 StgPtr scavd_hpLim; /* scavenged. */
77 bdescr * scan_bd; /* block currently being scanned */
78 StgPtr scan; /* scan pointer in current block */
79 bdescr * new_large_objects; /* large objects collected so far */
80 bdescr * scavenged_large_objects; /* live large objs after GC (d-link) */
81 unsigned int n_scavenged_large_blocks;/* size of above */
82 bdescr * bitmap; /* bitmap for compacting collection */
85 typedef struct generation_ {
86 unsigned int no; /* generation number */
87 step * steps; /* steps */
88 unsigned int n_steps; /* number of steps */
89 unsigned int max_blocks; /* max blocks in step 0 */
90 bdescr *mut_list; /* mut objects in this gen (not G0)*/
92 /* temporary use during GC: */
93 bdescr *saved_mut_list;
95 /* stats information */
96 unsigned int collections;
97 unsigned int failed_promotions;
100 extern generation * RTS_VAR(generations);
102 extern generation * RTS_VAR(g0);
103 extern step * RTS_VAR(g0s0);
104 extern generation * RTS_VAR(oldest_gen);
106 /* -----------------------------------------------------------------------------
107 Initialisation / De-initialisation
108 -------------------------------------------------------------------------- */
110 extern void initStorage(void);
111 extern void exitStorage(void);
112 extern void freeStorage(void);
114 /* -----------------------------------------------------------------------------
117 StgPtr allocateInGen(generation *g, nat n)
118 Allocates a chunk of contiguous store
119 n words long in generation g,
120 returning a pointer to the first word.
123 StgPtr allocate(nat n) Equaivalent to allocateInGen(g0)
125 StgPtr allocateLocal(Capability *cap, nat n)
126 Allocates memory from the nursery in
127 the current Capability. This can be
128 done without taking a global lock,
131 StgPtr allocatePinned(nat n) Allocates a chunk of contiguous store
132 n words long, which is at a fixed
133 address (won't be moved by GC).
134 Returns a pointer to the first word.
137 NOTE: the GC can't in general handle
138 pinned objects, so allocatePinned()
139 can only be used for ByteArrays at the
142 Don't forget to TICK_ALLOC_XXX(...)
143 after calling allocate or
144 allocatePinned, for the
145 benefit of the ticky-ticky profiler.
147 rtsBool doYouWantToGC(void) Returns True if the storage manager is
148 ready to perform a GC, False otherwise.
150 lnat allocatedBytes(void) Returns the number of bytes allocated
151 via allocate() since the last GC.
152 Used in the reporting of statistics.
154 -------------------------------------------------------------------------- */
156 extern StgPtr allocate ( nat n );
157 extern StgPtr allocateInGen ( generation *g, nat n );
158 extern StgPtr allocateLocal ( Capability *cap, nat n );
159 extern StgPtr allocatePinned ( nat n );
160 extern lnat allocatedBytes ( void );
162 extern bdescr * RTS_VAR(small_alloc_list);
163 extern bdescr * RTS_VAR(large_alloc_list);
164 extern bdescr * RTS_VAR(pinned_object_block);
166 extern StgPtr RTS_VAR(alloc_Hp);
167 extern StgPtr RTS_VAR(alloc_HpLim);
169 extern nat RTS_VAR(alloc_blocks);
170 extern nat RTS_VAR(alloc_blocks_lim);
172 INLINE_HEADER rtsBool
173 doYouWantToGC( void )
175 return (alloc_blocks >= alloc_blocks_lim);
178 /* memory allocator for executable memory */
179 extern void *allocateExec (nat bytes);
180 extern void freeExec (void *p);
182 /* -----------------------------------------------------------------------------
183 Performing Garbage Collection
185 GarbageCollect(get_roots) Performs a garbage collection.
186 'get_roots' is called to find all the
187 roots that the system knows about.
190 -------------------------------------------------------------------------- */
192 extern void GarbageCollect(rtsBool force_major_gc);
194 /* -----------------------------------------------------------------------------
195 Generational garbage collection support
197 recordMutable(StgPtr p) Informs the garbage collector that a
198 previously immutable object has
199 become (permanently) mutable. Used
200 by thawArray and similar.
202 updateWithIndirection(p1,p2) Updates the object at p1 with an
203 indirection pointing to p2. This is
204 normally called for objects in an old
205 generation (>0) when they are updated.
207 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
209 -------------------------------------------------------------------------- */
212 * Storage manager mutex
214 #if defined(THREADED_RTS)
215 extern Mutex sm_mutex;
216 extern Mutex atomic_modify_mutvar_mutex;
219 #if defined(THREADED_RTS)
220 #define ACQUIRE_SM_LOCK ACQUIRE_LOCK(&sm_mutex);
221 #define RELEASE_SM_LOCK RELEASE_LOCK(&sm_mutex);
222 #define ASSERT_SM_LOCK() ASSERT_LOCK_HELD(&sm_mutex);
224 #define ACQUIRE_SM_LOCK
225 #define RELEASE_SM_LOCK
226 #define ASSERT_SM_LOCK()
230 recordMutableGen(StgClosure *p, generation *gen)
235 if (bd->free >= bd->start + BLOCK_SIZE_W) {
237 new_bd = allocBlock();
242 *bd->free++ = (StgWord)p;
247 recordMutableGenLock(StgClosure *p, generation *gen)
250 recordMutableGen(p,gen);
255 recordMutable(StgClosure *p)
258 ASSERT(closure_MUTABLE(p));
260 if (bd->gen_no > 0) recordMutableGen(p, &RTS_DEREF(generations)[bd->gen_no]);
264 recordMutableLock(StgClosure *p)
271 /* -----------------------------------------------------------------------------
272 The CAF table - used to let us revert CAFs in GHCi
273 -------------------------------------------------------------------------- */
275 /* set to disable CAF garbage collection in GHCi. */
276 /* (needed when dynamic libraries are used). */
277 extern rtsBool keepCAFs;
279 /* -----------------------------------------------------------------------------
280 This is the write barrier for MUT_VARs, a.k.a. IORefs. A
281 MUT_VAR_CLEAN object is not on the mutable list; a MUT_VAR_DIRTY
282 is. When written to, a MUT_VAR_CLEAN turns into a MUT_VAR_DIRTY
283 and is put on the mutable list.
284 -------------------------------------------------------------------------- */
286 void dirty_MUT_VAR(StgRegTable *reg, StgClosure *p);
288 /* -----------------------------------------------------------------------------
289 DEBUGGING predicates for pointers
291 LOOKS_LIKE_INFO_PTR(p) returns False if p is definitely not an info ptr
292 LOOKS_LIKE_CLOSURE_PTR(p) returns False if p is definitely not a closure ptr
294 These macros are complete but not sound. That is, they might
295 return false positives. Do not rely on them to distinguish info
296 pointers from closure pointers, for example.
298 We don't use address-space predicates these days, for portability
299 reasons, and the fact that code/data can be scattered about the
300 address space in a dynamically-linked environment. Our best option
301 is to look at the alleged info table and see whether it seems to
303 -------------------------------------------------------------------------- */
305 #define LOOKS_LIKE_INFO_PTR(p) \
306 (p && LOOKS_LIKE_INFO_PTR_NOT_NULL(p))
308 #define LOOKS_LIKE_INFO_PTR_NOT_NULL(p) \
309 (((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type != INVALID_OBJECT && \
310 ((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type < N_CLOSURE_TYPES)
312 #define LOOKS_LIKE_CLOSURE_PTR(p) \
313 (LOOKS_LIKE_INFO_PTR((UNTAG_CLOSURE((StgClosure *)(p)))->header.info))
315 /* -----------------------------------------------------------------------------
316 Macros for calculating how big a closure will be (used during allocation)
317 -------------------------------------------------------------------------- */
319 INLINE_HEADER StgOffset PAP_sizeW ( nat n_args )
320 { return sizeofW(StgPAP) + n_args; }
322 INLINE_HEADER StgOffset AP_sizeW ( nat n_args )
323 { return sizeofW(StgAP) + n_args; }
325 INLINE_HEADER StgOffset AP_STACK_sizeW ( nat size )
326 { return sizeofW(StgAP_STACK) + size; }
328 INLINE_HEADER StgOffset CONSTR_sizeW( nat p, nat np )
329 { return sizeofW(StgHeader) + p + np; }
331 INLINE_HEADER StgOffset THUNK_SELECTOR_sizeW ( void )
332 { return sizeofW(StgSelector); }
334 INLINE_HEADER StgOffset BLACKHOLE_sizeW ( void )
335 { return sizeofW(StgHeader)+MIN_PAYLOAD_SIZE; }
337 /* --------------------------------------------------------------------------
339 ------------------------------------------------------------------------*/
341 INLINE_HEADER StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
342 { return sizeofW(StgClosure)
343 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
344 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
346 INLINE_HEADER StgOffset thunk_sizeW_fromITBL( const StgInfoTable* itbl )
347 { return sizeofW(StgThunk)
348 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
349 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
351 INLINE_HEADER StgOffset ap_stack_sizeW( StgAP_STACK* x )
352 { return AP_STACK_sizeW(x->size); }
354 INLINE_HEADER StgOffset ap_sizeW( StgAP* x )
355 { return AP_sizeW(x->n_args); }
357 INLINE_HEADER StgOffset pap_sizeW( StgPAP* x )
358 { return PAP_sizeW(x->n_args); }
360 INLINE_HEADER StgOffset arr_words_sizeW( StgArrWords* x )
361 { return sizeofW(StgArrWords) + x->words; }
363 INLINE_HEADER StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
364 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
366 INLINE_HEADER StgWord tso_sizeW ( StgTSO *tso )
367 { return TSO_STRUCT_SIZEW + tso->stack_size; }
369 INLINE_HEADER StgWord bco_sizeW ( StgBCO *bco )
370 { return bco->size; }
373 closure_sizeW_ (StgClosure *p, StgInfoTable *info)
375 switch (info->type) {
378 return sizeofW(StgThunk) + 1;
383 return sizeofW(StgHeader) + 1;
387 return sizeofW(StgThunk) + 2;
394 return sizeofW(StgHeader) + 2;
396 return thunk_sizeW_fromITBL(info);
398 return THUNK_SELECTOR_sizeW();
400 return ap_stack_sizeW((StgAP_STACK *)p);
402 return ap_sizeW((StgAP *)p);
404 return pap_sizeW((StgPAP *)p);
408 case IND_OLDGEN_PERM:
409 return sizeofW(StgInd);
411 return arr_words_sizeW((StgArrWords *)p);
412 case MUT_ARR_PTRS_CLEAN:
413 case MUT_ARR_PTRS_DIRTY:
414 case MUT_ARR_PTRS_FROZEN:
415 case MUT_ARR_PTRS_FROZEN0:
416 return mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
418 return tso_sizeW((StgTSO *)p);
420 return bco_sizeW((StgBCO *)p);
421 case TVAR_WATCH_QUEUE:
422 return sizeofW(StgTVarWatchQueue);
424 return sizeofW(StgTVar);
426 return sizeofW(StgTRecChunk);
428 return sizeofW(StgTRecHeader);
429 case ATOMIC_INVARIANT:
430 return sizeofW(StgAtomicInvariant);
431 case INVARIANT_CHECK_QUEUE:
432 return sizeofW(StgInvariantCheckQueue);
434 return sizeW_fromITBL(info);
438 // The definitive way to find the size, in words, of a heap-allocated closure
440 closure_sizeW (StgClosure *p)
442 return closure_sizeW_(p, get_itbl(p));
445 /* -----------------------------------------------------------------------------
446 Sizes of stack frames
447 -------------------------------------------------------------------------- */
449 INLINE_HEADER StgWord stack_frame_sizeW( StgClosure *frame )
451 StgRetInfoTable *info;
453 info = get_ret_itbl(frame);
454 switch (info->i.type) {
458 StgRetDyn *dyn = (StgRetDyn *)frame;
459 return sizeofW(StgRetDyn) + RET_DYN_BITMAP_SIZE +
460 RET_DYN_NONPTR_REGS_SIZE +
461 RET_DYN_PTRS(dyn->liveness) + RET_DYN_NONPTRS(dyn->liveness);
465 return sizeofW(StgRetFun) + ((StgRetFun *)frame)->size;
468 return 1 + GET_LARGE_BITMAP(&info->i)->size;
471 return 2 + BCO_BITMAP_SIZE((StgBCO *)((P_)frame)[1]);
474 return 1 + BITMAP_SIZE(info->i.layout.bitmap);
478 /* -----------------------------------------------------------------------------
480 -------------------------------------------------------------------------- */
482 extern void allocNurseries ( void );
483 extern void resetNurseries ( void );
484 extern void resizeNurseries ( nat blocks );
485 extern void resizeNurseriesFixed ( nat blocks );
486 extern lnat countNurseryBlocks ( void );
488 /* -----------------------------------------------------------------------------
490 -------------------------------------------------------------------------- */
492 typedef void (*evac_fn)(StgClosure **);
494 extern void threadPaused ( Capability *cap, StgTSO * );
495 extern StgClosure * isAlive ( StgClosure *p );
496 extern void markCAFs ( evac_fn evac );
497 extern void GetRoots ( evac_fn evac );
499 /* -----------------------------------------------------------------------------
500 Stats 'n' DEBUG stuff
501 -------------------------------------------------------------------------- */
503 extern ullong RTS_VAR(total_allocated);
505 extern lnat calcAllocated ( void );
506 extern lnat calcLive ( void );
507 extern lnat calcNeeded ( void );
510 extern void memInventory(void);
511 extern void checkSanity(void);
512 extern nat countBlocks(bdescr *);
513 extern void checkNurserySanity( step *stp );
517 void printMutOnceList(generation *gen);
518 void printMutableList(generation *gen);
521 /* ----------------------------------------------------------------------------
522 Storage manager internal APIs and globals
523 ------------------------------------------------------------------------- */
525 #define END_OF_STATIC_LIST stgCast(StgClosure*,1)
527 extern void newDynCAF(StgClosure *);
529 extern void move_TSO(StgTSO *src, StgTSO *dest);
530 extern StgTSO *relocate_stack(StgTSO *dest, ptrdiff_t diff);
532 extern StgClosure * RTS_VAR(scavenged_static_objects);
533 extern StgWeak * RTS_VAR(old_weak_ptr_list);
534 extern StgWeak * RTS_VAR(weak_ptr_list);
535 extern StgClosure * RTS_VAR(caf_list);
536 extern StgClosure * RTS_VAR(revertible_caf_list);
537 extern StgTSO * RTS_VAR(resurrected_threads);
539 #endif /* STORAGE_H */