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 allocate(nat n) Allocates a chunk of contiguous store
118 n words long, returning a pointer to
119 the first word. Always succeeds.
121 StgPtr allocatePinned(nat n) Allocates a chunk of contiguous store
122 n words long, which is at a fixed
123 address (won't be moved by GC).
124 Returns a pointer to the first word.
127 NOTE: the GC can't in general handle
128 pinned objects, so allocatePinned()
129 can only be used for ByteArrays at the
132 Don't forget to TICK_ALLOC_XXX(...)
133 after calling allocate or
134 allocatePinned, for the
135 benefit of the ticky-ticky profiler.
137 rtsBool doYouWantToGC(void) Returns True if the storage manager is
138 ready to perform a GC, False otherwise.
140 lnat allocated_bytes(void) Returns the number of bytes allocated
141 via allocate() since the last GC.
142 Used in the reporting of statistics.
144 THREADED_RTS: allocate and doYouWantToGC can be used from STG code, they are
145 surrounded by a mutex.
146 -------------------------------------------------------------------------- */
148 extern StgPtr allocate ( nat n );
149 extern StgPtr allocateLocal ( Capability *cap, nat n );
150 extern StgPtr allocatePinned ( nat n );
151 extern lnat allocated_bytes ( void );
153 extern bdescr * RTS_VAR(small_alloc_list);
154 extern bdescr * RTS_VAR(large_alloc_list);
155 extern bdescr * RTS_VAR(pinned_object_block);
157 extern StgPtr RTS_VAR(alloc_Hp);
158 extern StgPtr RTS_VAR(alloc_HpLim);
160 extern nat RTS_VAR(alloc_blocks);
161 extern nat RTS_VAR(alloc_blocks_lim);
163 INLINE_HEADER rtsBool
164 doYouWantToGC( void )
166 return (alloc_blocks >= alloc_blocks_lim);
169 /* -----------------------------------------------------------------------------
170 Performing Garbage Collection
172 GarbageCollect(get_roots) Performs a garbage collection.
173 'get_roots' is called to find all the
174 roots that the system knows about.
176 StgClosure Called by get_roots on each root.
177 MarkRoot(StgClosure *p) Returns the new location of the root.
178 -------------------------------------------------------------------------- */
180 extern void GarbageCollect(void (*get_roots)(evac_fn),rtsBool force_major_gc);
182 /* -----------------------------------------------------------------------------
183 Generational garbage collection support
185 recordMutable(StgPtr p) Informs the garbage collector that a
186 previously immutable object has
187 become (permanently) mutable. Used
188 by thawArray and similar.
190 updateWithIndirection(p1,p2) Updates the object at p1 with an
191 indirection pointing to p2. This is
192 normally called for objects in an old
193 generation (>0) when they are updated.
195 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
197 -------------------------------------------------------------------------- */
200 * Storage manager mutex
202 #if defined(THREADED_RTS)
203 extern Mutex sm_mutex;
204 extern Mutex atomic_modify_mutvar_mutex;
207 #if defined(THREADED_RTS)
208 #define ACQUIRE_SM_LOCK ACQUIRE_LOCK(&sm_mutex);
209 #define RELEASE_SM_LOCK RELEASE_LOCK(&sm_mutex);
210 #define ASSERT_SM_LOCK() ASSERT_LOCK_HELD(&sm_mutex);
212 #define ACQUIRE_SM_LOCK
213 #define RELEASE_SM_LOCK
214 #define ASSERT_SM_LOCK()
218 recordMutableGen(StgClosure *p, generation *gen)
223 if (bd->free >= bd->start + BLOCK_SIZE_W) {
225 new_bd = allocBlock();
230 *bd->free++ = (StgWord)p;
235 recordMutableGenLock(StgClosure *p, generation *gen)
238 recordMutableGen(p,gen);
243 recordMutable(StgClosure *p)
246 ASSERT(closure_MUTABLE(p));
248 if (bd->gen_no > 0) recordMutableGen(p, &RTS_DEREF(generations)[bd->gen_no]);
252 recordMutableLock(StgClosure *p)
259 /* -----------------------------------------------------------------------------
260 The CAF table - used to let us revert CAFs in GHCi
261 -------------------------------------------------------------------------- */
263 /* set to disable CAF garbage collection in GHCi. */
264 /* (needed when dynamic libraries are used). */
265 extern rtsBool keepCAFs;
267 /* -----------------------------------------------------------------------------
268 This is the write barrier for MUT_VARs, a.k.a. IORefs. A
269 MUT_VAR_CLEAN object is not on the mutable list; a MUT_VAR_DIRTY
270 is. When written to, a MUT_VAR_CLEAN turns into a MUT_VAR_DIRTY
271 and is put on the mutable list.
272 -------------------------------------------------------------------------- */
274 void dirty_MUT_VAR(StgRegTable *reg, StgClosure *p);
276 /* -----------------------------------------------------------------------------
277 DEBUGGING predicates for pointers
279 LOOKS_LIKE_INFO_PTR(p) returns False if p is definitely not an info ptr
280 LOOKS_LIKE_CLOSURE_PTR(p) returns False if p is definitely not a closure ptr
282 These macros are complete but not sound. That is, they might
283 return false positives. Do not rely on them to distinguish info
284 pointers from closure pointers, for example.
286 We don't use address-space predicates these days, for portability
287 reasons, and the fact that code/data can be scattered about the
288 address space in a dynamically-linked environment. Our best option
289 is to look at the alleged info table and see whether it seems to
291 -------------------------------------------------------------------------- */
293 #define LOOKS_LIKE_INFO_PTR(p) \
294 (p && ((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type != INVALID_OBJECT && \
295 ((StgInfoTable *)(INFO_PTR_TO_STRUCT(p)))->type < N_CLOSURE_TYPES)
297 #define LOOKS_LIKE_CLOSURE_PTR(p) \
298 (LOOKS_LIKE_INFO_PTR(((StgClosure *)(p))->header.info))
300 /* -----------------------------------------------------------------------------
301 Macros for calculating how big a closure will be (used during allocation)
302 -------------------------------------------------------------------------- */
304 INLINE_HEADER StgOffset PAP_sizeW ( nat n_args )
305 { return sizeofW(StgPAP) + n_args; }
307 INLINE_HEADER StgOffset AP_sizeW ( nat n_args )
308 { return sizeofW(StgAP) + n_args; }
310 INLINE_HEADER StgOffset AP_STACK_sizeW ( nat size )
311 { return sizeofW(StgAP_STACK) + size; }
313 INLINE_HEADER StgOffset CONSTR_sizeW( nat p, nat np )
314 { return sizeofW(StgHeader) + p + np; }
316 INLINE_HEADER StgOffset THUNK_SELECTOR_sizeW ( void )
317 { return sizeofW(StgSelector); }
319 INLINE_HEADER StgOffset BLACKHOLE_sizeW ( void )
320 { return sizeofW(StgHeader)+MIN_PAYLOAD_SIZE; }
322 /* --------------------------------------------------------------------------
324 ------------------------------------------------------------------------*/
326 INLINE_HEADER StgOffset sizeW_fromITBL( const StgInfoTable* itbl )
327 { return sizeofW(StgClosure)
328 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
329 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
331 INLINE_HEADER StgOffset thunk_sizeW_fromITBL( const StgInfoTable* itbl )
332 { return sizeofW(StgThunk)
333 + sizeofW(StgPtr) * itbl->layout.payload.ptrs
334 + sizeofW(StgWord) * itbl->layout.payload.nptrs; }
336 INLINE_HEADER StgOffset ap_stack_sizeW( StgAP_STACK* x )
337 { return AP_STACK_sizeW(x->size); }
339 INLINE_HEADER StgOffset ap_sizeW( StgAP* x )
340 { return AP_sizeW(x->n_args); }
342 INLINE_HEADER StgOffset pap_sizeW( StgPAP* x )
343 { return PAP_sizeW(x->n_args); }
345 INLINE_HEADER StgOffset arr_words_sizeW( StgArrWords* x )
346 { return sizeofW(StgArrWords) + x->words; }
348 INLINE_HEADER StgOffset mut_arr_ptrs_sizeW( StgMutArrPtrs* x )
349 { return sizeofW(StgMutArrPtrs) + x->ptrs; }
351 INLINE_HEADER StgWord tso_sizeW ( StgTSO *tso )
352 { return TSO_STRUCT_SIZEW + tso->stack_size; }
354 INLINE_HEADER StgWord bco_sizeW ( StgBCO *bco )
355 { return bco->size; }
358 closure_sizeW_ (StgClosure *p, StgInfoTable *info)
360 switch (info->type) {
363 return sizeofW(StgThunk) + 1;
368 return sizeofW(StgHeader) + 1;
372 return sizeofW(StgThunk) + 2;
379 return sizeofW(StgHeader) + 2;
381 return thunk_sizeW_fromITBL(info);
383 return THUNK_SELECTOR_sizeW();
385 return ap_stack_sizeW((StgAP_STACK *)p);
388 return pap_sizeW((StgPAP *)p);
392 case IND_OLDGEN_PERM:
393 return sizeofW(StgInd);
395 return arr_words_sizeW((StgArrWords *)p);
396 case MUT_ARR_PTRS_CLEAN:
397 case MUT_ARR_PTRS_DIRTY:
398 case MUT_ARR_PTRS_FROZEN:
399 case MUT_ARR_PTRS_FROZEN0:
400 return mut_arr_ptrs_sizeW((StgMutArrPtrs*)p);
402 return tso_sizeW((StgTSO *)p);
404 return bco_sizeW((StgBCO *)p);
405 case TVAR_WAIT_QUEUE:
406 return sizeofW(StgTVarWaitQueue);
408 return sizeofW(StgTVar);
410 return sizeofW(StgTRecChunk);
412 return sizeofW(StgTRecHeader);
414 return sizeW_fromITBL(info);
418 // The definitive way to find the size, in words, of a heap-allocated closure
420 closure_sizeW (StgClosure *p)
422 return closure_sizeW_(p, get_itbl(p));
425 /* -----------------------------------------------------------------------------
426 Sizes of stack frames
427 -------------------------------------------------------------------------- */
429 INLINE_HEADER StgWord stack_frame_sizeW( StgClosure *frame )
431 StgRetInfoTable *info;
433 info = get_ret_itbl(frame);
434 switch (info->i.type) {
438 StgRetDyn *dyn = (StgRetDyn *)frame;
439 return sizeofW(StgRetDyn) + RET_DYN_BITMAP_SIZE +
440 RET_DYN_NONPTR_REGS_SIZE +
441 RET_DYN_PTRS(dyn->liveness) + RET_DYN_NONPTRS(dyn->liveness);
445 return sizeofW(StgRetFun) + ((StgRetFun *)frame)->size;
449 return 1 + GET_LARGE_BITMAP(&info->i)->size;
452 return 2 + BCO_BITMAP_SIZE((StgBCO *)((P_)frame)[1]);
455 return 1 + BITMAP_SIZE(info->i.layout.bitmap);
459 /* -----------------------------------------------------------------------------
461 -------------------------------------------------------------------------- */
463 extern void allocNurseries ( void );
464 extern void resetNurseries ( void );
465 extern void resizeNurseries ( nat blocks );
466 extern void resizeNurseriesFixed ( nat blocks );
467 extern void tidyAllocateLists ( void );
468 extern lnat countNurseryBlocks ( void );
470 /* -----------------------------------------------------------------------------
472 -------------------------------------------------------------------------- */
474 extern void threadPaused ( Capability *cap, StgTSO * );
475 extern StgClosure * isAlive ( StgClosure *p );
476 extern void markCAFs ( evac_fn evac );
478 /* -----------------------------------------------------------------------------
479 Stats 'n' DEBUG stuff
480 -------------------------------------------------------------------------- */
482 extern ullong RTS_VAR(total_allocated);
484 extern lnat calcAllocated ( void );
485 extern lnat calcLive ( void );
486 extern lnat calcNeeded ( void );
489 extern void memInventory(void);
490 extern void checkSanity(void);
491 extern nat countBlocks(bdescr *);
492 extern void checkNurserySanity( step *stp );
496 void printMutOnceList(generation *gen);
497 void printMutableList(generation *gen);
500 /* ----------------------------------------------------------------------------
501 Storage manager internal APIs and globals
502 ------------------------------------------------------------------------- */
504 #define END_OF_STATIC_LIST stgCast(StgClosure*,1)
506 extern void newDynCAF(StgClosure *);
508 extern void move_TSO(StgTSO *src, StgTSO *dest);
509 extern StgTSO *relocate_stack(StgTSO *dest, ptrdiff_t diff);
511 extern StgClosure * RTS_VAR(scavenged_static_objects);
512 extern StgWeak * RTS_VAR(old_weak_ptr_list);
513 extern StgWeak * RTS_VAR(weak_ptr_list);
514 extern StgClosure * RTS_VAR(caf_list);
515 extern StgClosure * RTS_VAR(revertible_caf_list);
516 extern StgTSO * RTS_VAR(resurrected_threads);
518 #endif /* STORAGE_H */