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
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
64 unsigned int n_words; // number of words
66 struct step_ * to; // destination step for live objects
68 bdescr * large_objects; // large objects (doubly linked)
69 unsigned int n_large_blocks; // no. of blocks used by large objs
71 StgTSO * threads; // threads in this step
72 // linked via global_link
74 // ------------------------------------
75 // Fields below are used during GC only
77 // During GC, if we are collecting this step, blocks and n_blocks
78 // are copied into the following two fields. After GC, these blocks
81 #if defined(THREADED_RTS)
82 char pad[128]; // make sure the following is
83 // on a separate cache line.
84 SpinLock sync_todo; // lock for todos
85 SpinLock sync_large_objects; // lock for large_objects
86 // and scavenged_large_objects
89 int mark; // mark (not copy)? (old gen only)
90 int compact; // compact (not sweep)? (old gen only)
92 bdescr * old_blocks; // bdescr of first from-space block
93 unsigned int n_old_blocks; // number of blocks in from-space
94 unsigned int live_estimate; // for sweeping: estimate of live data
96 bdescr * todos; // blocks waiting to be scavenged
98 unsigned int n_todos; // count of above
100 bdescr * part_blocks; // partially-full scanned blocks
101 unsigned int n_part_blocks; // count of above
103 bdescr * scavenged_large_objects; // live large objs after GC (d-link)
104 unsigned int n_scavenged_large_blocks; // size (not count) of above
106 bdescr * bitmap; // bitmap for compacting collection
108 StgTSO * old_threads;
113 typedef struct generation_ {
114 unsigned int no; // generation number
115 step * steps; // steps
116 unsigned int n_steps; // number of steps
117 unsigned int max_blocks; // max blocks in step 0
118 bdescr *mut_list; // mut objects in this gen (not G0)
121 unsigned int collections;
122 unsigned int par_collections;
123 unsigned int failed_promotions;
125 // temporary use during GC:
126 bdescr *saved_mut_list;
129 extern generation * RTS_VAR(generations);
131 extern generation * RTS_VAR(g0);
132 extern step * RTS_VAR(g0s0);
133 extern generation * RTS_VAR(oldest_gen);
134 extern step * RTS_VAR(all_steps);
135 extern nat RTS_VAR(total_steps);
137 /* -----------------------------------------------------------------------------
138 Initialisation / De-initialisation
139 -------------------------------------------------------------------------- */
141 extern void initStorage(void);
142 extern void exitStorage(void);
143 extern void freeStorage(void);
145 /* -----------------------------------------------------------------------------
148 StgPtr allocateInGen(generation *g, nat n)
149 Allocates a chunk of contiguous store
150 n words long in generation g,
151 returning a pointer to the first word.
154 StgPtr allocate(nat n) Equaivalent to allocateInGen(g0)
156 StgPtr allocateLocal(Capability *cap, nat n)
157 Allocates memory from the nursery in
158 the current Capability. This can be
159 done without taking a global lock,
162 StgPtr allocatePinned(nat n) Allocates a chunk of contiguous store
163 n words long, which is at a fixed
164 address (won't be moved by GC).
165 Returns a pointer to the first word.
168 NOTE: the GC can't in general handle
169 pinned objects, so allocatePinned()
170 can only be used for ByteArrays at the
173 Don't forget to TICK_ALLOC_XXX(...)
174 after calling allocate or
175 allocatePinned, for the
176 benefit of the ticky-ticky profiler.
178 rtsBool doYouWantToGC(void) Returns True if the storage manager is
179 ready to perform a GC, False otherwise.
181 lnat allocatedBytes(void) Returns the number of bytes allocated
182 via allocate() since the last GC.
183 Used in the reporting of statistics.
185 -------------------------------------------------------------------------- */
187 extern StgPtr allocate ( lnat n );
188 extern StgPtr allocateInGen ( generation *g, lnat n );
189 extern StgPtr allocateLocal ( Capability *cap, lnat n );
190 extern StgPtr allocatePinned ( lnat n );
191 extern lnat allocatedBytes ( void );
193 extern bdescr * RTS_VAR(small_alloc_list);
194 extern bdescr * RTS_VAR(large_alloc_list);
195 extern bdescr * RTS_VAR(pinned_object_block);
197 extern nat RTS_VAR(alloc_blocks);
198 extern nat RTS_VAR(alloc_blocks_lim);
200 INLINE_HEADER rtsBool
201 doYouWantToGC( void )
203 return (alloc_blocks >= alloc_blocks_lim);
206 /* memory allocator for executable memory */
207 extern void* allocateExec(unsigned int len, void **exec_addr);
208 extern void freeExec (void *p);
210 /* for splitting blocks groups in two */
211 extern bdescr * splitLargeBlock (bdescr *bd, nat blocks);
213 /* -----------------------------------------------------------------------------
214 Performing Garbage Collection
216 GarbageCollect(get_roots) Performs a garbage collection.
217 'get_roots' is called to find all the
218 roots that the system knows about.
221 -------------------------------------------------------------------------- */
223 extern void GarbageCollect(rtsBool force_major_gc, nat gc_type, Capability *cap);
225 /* -----------------------------------------------------------------------------
226 Generational garbage collection support
228 recordMutable(StgPtr p) Informs the garbage collector that a
229 previously immutable object has
230 become (permanently) mutable. Used
231 by thawArray and similar.
233 updateWithIndirection(p1,p2) Updates the object at p1 with an
234 indirection pointing to p2. This is
235 normally called for objects in an old
236 generation (>0) when they are updated.
238 updateWithPermIndirection(p1,p2) As above but uses a permanent indir.
240 -------------------------------------------------------------------------- */
243 * Storage manager mutex
245 #if defined(THREADED_RTS)
246 extern Mutex sm_mutex;
247 extern Mutex atomic_modify_mutvar_mutex;
248 extern SpinLock recordMutableGen_sync;
251 #if defined(THREADED_RTS)
252 #define ACQUIRE_SM_LOCK ACQUIRE_LOCK(&sm_mutex);
253 #define RELEASE_SM_LOCK RELEASE_LOCK(&sm_mutex);
254 #define ASSERT_SM_LOCK() ASSERT_LOCK_HELD(&sm_mutex);
256 #define ACQUIRE_SM_LOCK
257 #define RELEASE_SM_LOCK
258 #define ASSERT_SM_LOCK()
262 recordMutableGen(StgClosure *p, generation *gen)
267 if (bd->free >= bd->start + BLOCK_SIZE_W) {
269 new_bd = allocBlock();
274 *bd->free++ = (StgWord)p;
279 recordMutableGenLock(StgClosure *p, generation *gen)
282 recordMutableGen(p,gen);
286 extern bdescr *allocBlock_sync(void);
288 // Version of recordMutableGen() for use in parallel GC. The same as
289 // recordMutableGen(), except that we surround it with a spinlock and
290 // call the spinlock version of allocBlock().
292 recordMutableGen_GC(StgClosure *p, generation *gen)
296 ACQUIRE_SPIN_LOCK(&recordMutableGen_sync);
299 if (bd->free >= bd->start + BLOCK_SIZE_W) {
301 new_bd = allocBlock_sync();
306 *bd->free++ = (StgWord)p;
308 RELEASE_SPIN_LOCK(&recordMutableGen_sync);
312 recordMutable(StgClosure *p)
315 ASSERT(closure_MUTABLE(p));
317 if (bd->gen_no > 0) recordMutableGen(p, &RTS_DEREF(generations)[bd->gen_no]);
321 recordMutableLock(StgClosure *p)
328 /* -----------------------------------------------------------------------------
329 The CAF table - used to let us revert CAFs in GHCi
330 -------------------------------------------------------------------------- */
332 /* set to disable CAF garbage collection in GHCi. */
333 /* (needed when dynamic libraries are used). */
334 extern rtsBool keepCAFs;
336 /* -----------------------------------------------------------------------------
337 This is the write barrier for MUT_VARs, a.k.a. IORefs. A
338 MUT_VAR_CLEAN object is not on the mutable list; a MUT_VAR_DIRTY
339 is. When written to, a MUT_VAR_CLEAN turns into a MUT_VAR_DIRTY
340 and is put on the mutable list.
341 -------------------------------------------------------------------------- */
343 void dirty_MUT_VAR(StgRegTable *reg, StgClosure *p);
345 /* -----------------------------------------------------------------------------
346 DEBUGGING predicates for pointers
348 LOOKS_LIKE_INFO_PTR(p) returns False if p is definitely not an info ptr
349 LOOKS_LIKE_CLOSURE_PTR(p) returns False if p is definitely not a closure ptr
351 These macros are complete but not sound. That is, they might
352 return false positives. Do not rely on them to distinguish info
353 pointers from closure pointers, for example.
355 We don't use address-space predicates these days, for portability
356 reasons, and the fact that code/data can be scattered about the
357 address space in a dynamically-linked environment. Our best option
358 is to look at the alleged info table and see whether it seems to
360 -------------------------------------------------------------------------- */
362 INLINE_HEADER rtsBool LOOKS_LIKE_INFO_PTR (StgWord p);
363 INLINE_HEADER rtsBool LOOKS_LIKE_CLOSURE_PTR (void *p); // XXX StgClosure*
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 );
539 /* -----------------------------------------------------------------------------
541 -------------------------------------------------------------------------- */
543 typedef void (*evac_fn)(void *user, StgClosure **root);
545 extern void threadPaused ( Capability *cap, StgTSO * );
546 extern StgClosure * isAlive ( StgClosure *p );
547 extern void markCAFs ( evac_fn evac, void *user );
548 extern void GetRoots ( evac_fn evac, void *user );
550 /* -----------------------------------------------------------------------------
551 Stats 'n' DEBUG stuff
552 -------------------------------------------------------------------------- */
554 extern ullong RTS_VAR(total_allocated);
556 extern lnat calcAllocated ( void );
557 extern lnat calcLiveBlocks ( void );
558 extern lnat calcLiveWords ( void );
559 extern lnat countOccupied ( bdescr *bd );
560 extern lnat calcNeeded ( void );
563 extern void memInventory(rtsBool show);
564 extern void checkSanity(void);
565 extern nat countBlocks(bdescr *);
566 extern void checkNurserySanity( step *stp );
570 void printMutOnceList(generation *gen);
571 void printMutableList(generation *gen);
574 /* ----------------------------------------------------------------------------
575 Storage manager internal APIs and globals
576 ------------------------------------------------------------------------- */
578 #define END_OF_STATIC_LIST stgCast(StgClosure*,1)
580 extern void newDynCAF(StgClosure *);
582 extern void move_TSO(StgTSO *src, StgTSO *dest);
583 extern StgTSO *relocate_stack(StgTSO *dest, ptrdiff_t diff);
585 extern StgWeak * RTS_VAR(old_weak_ptr_list);
586 extern StgWeak * RTS_VAR(weak_ptr_list);
587 extern StgClosure * RTS_VAR(caf_list);
588 extern StgClosure * RTS_VAR(revertible_caf_list);
589 extern StgTSO * RTS_VAR(resurrected_threads);
591 #define IS_FORWARDING_PTR(p) ((((StgWord)p) & 1) != 0)
592 #define MK_FORWARDING_PTR(p) (((StgWord)p) | 1)
593 #define UN_FORWARDING_PTR(p) (((StgWord)p) - 1)
595 INLINE_HEADER rtsBool LOOKS_LIKE_INFO_PTR_NOT_NULL (StgWord p)
597 StgInfoTable *info = INFO_PTR_TO_STRUCT(p);
598 return info->type != INVALID_OBJECT && info->type < N_CLOSURE_TYPES;
601 INLINE_HEADER rtsBool LOOKS_LIKE_INFO_PTR (StgWord p)
603 return p && (IS_FORWARDING_PTR(p) || LOOKS_LIKE_INFO_PTR_NOT_NULL(p));
606 INLINE_HEADER rtsBool LOOKS_LIKE_CLOSURE_PTR (void *p)
608 return LOOKS_LIKE_INFO_PTR((StgWord)(UNTAG_CLOSURE((StgClosure *)(p)))->header.info);
611 #endif /* STORAGE_H */