3 * Simple generational GC.
5 * Copyright 2001-2003 Ximian, Inc
6 * Copyright 2003-2010 Novell, Inc.
7 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
8 * Copyright (C) 2012 Xamarin Inc
10 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
12 #ifndef __MONO_SGENGC_H__
13 #define __MONO_SGENGC_H__
20 typedef struct _SgenThreadInfo SgenThreadInfo;
21 #undef THREAD_INFO_TYPE
22 #define THREAD_INFO_TYPE SgenThreadInfo
30 #include "mono/utils/mono-compiler.h"
31 #include "mono/utils/atomic.h"
32 #include "mono/utils/mono-os-mutex.h"
33 #include "mono/utils/mono-coop-mutex.h"
34 #include "mono/sgen/sgen-conf.h"
35 #include "mono/sgen/sgen-hash-table.h"
36 #include "mono/sgen/sgen-protocol.h"
37 #include "mono/sgen/gc-internal-agnostic.h"
38 #include "mono/sgen/sgen-thread-pool.h"
40 /* The method used to clear the nursery */
41 /* Clearing at nursery collections is the safest, but has bad interactions with caches.
42 * Clearing at TLAB creation is much faster, but more complex and it might expose hard
47 CLEAR_AT_TLAB_CREATION,
48 CLEAR_AT_TLAB_CREATION_DEBUG
51 NurseryClearPolicy sgen_get_nursery_clear_policy (void);
53 #if !defined(__MACH__) && !MONO_MACH_ARCH_SUPPORTED && defined(HAVE_PTHREAD_KILL)
54 #define SGEN_POSIX_STW 1
58 * The nursery section uses this struct.
60 typedef struct _GCMemSection GCMemSection;
61 struct _GCMemSection {
65 * scan starts is an array of pointers to objects equally spaced in the allocation area
66 * They let use quickly find pinned objects from pinning pointers.
69 /* in major collections indexes in the pin_queue for objects that pin this section */
70 size_t pin_queue_first_entry;
71 size_t pin_queue_last_entry;
72 size_t num_scan_start;
76 * Recursion is not allowed for the thread lock.
78 #define LOCK_DECLARE(name) mono_mutex_t name
79 /* if changing LOCK_INIT to something that isn't idempotent, look at
80 its use in mono_gc_base_init in sgen-gc.c */
81 #define LOCK_INIT(name) mono_os_mutex_init (&(name))
82 #define LOCK_GC do { sgen_gc_lock (); } while (0)
83 #define UNLOCK_GC do { sgen_gc_unlock (); } while (0)
85 extern MonoCoopMutex sgen_interruption_mutex;
87 #define LOCK_INTERRUPTION mono_coop_mutex_lock (&sgen_interruption_mutex)
88 #define UNLOCK_INTERRUPTION mono_coop_mutex_unlock (&sgen_interruption_mutex)
90 /* FIXME: Use InterlockedAdd & InterlockedAdd64 to reduce the CAS cost. */
91 #define SGEN_CAS InterlockedCompareExchange
92 #define SGEN_CAS_PTR InterlockedCompareExchangePointer
93 #define SGEN_ATOMIC_ADD(x,i) do { \
97 } while (InterlockedCompareExchange (&(x), __old_x + (i), __old_x) != __old_x); \
99 #define SGEN_ATOMIC_ADD_P(x,i) do { \
103 } while (InterlockedCompareExchangePointer ((void**)&(x), (void*)(__old_x + (i)), (void*)__old_x) != (void*)__old_x); \
106 #ifdef HEAVY_STATISTICS
107 extern guint64 stat_objects_alloced_degraded;
108 extern guint64 stat_bytes_alloced_degraded;
109 extern guint64 stat_copy_object_called_major;
110 extern guint64 stat_objects_copied_major;
113 #define SGEN_ASSERT(level, a, ...) do { \
114 if (G_UNLIKELY ((level) <= SGEN_MAX_ASSERT_LEVEL && !(a))) { \
115 g_error (__VA_ARGS__); \
118 #ifdef HAVE_LOCALTIME_R
119 # define LOG_TIMESTAMP \
124 localtime_r(&t, &tod); \
125 strftime(logTime, sizeof(logTime), "%Y-%m-%d %H:%M:%S", &tod); \
128 # define LOG_TIMESTAMP \
133 tod = localtime(&t); \
134 strftime(logTime, sizeof(logTime), "%F %T", tod); \
138 #define SGEN_LOG(level, format, ...) do { \
139 if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) { \
142 mono_gc_printf (gc_debug_file, "%s " format "\n", logTime, ##__VA_ARGS__); \
145 #define SGEN_COND_LOG(level, cond, format, ...) do { \
146 if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) { \
150 mono_gc_printf (gc_debug_file, "%s " format "\n", logTime, ##__VA_ARGS__); \
154 extern int gc_debug_level;
155 extern FILE* gc_debug_file;
157 extern int current_collection_generation;
159 extern unsigned int sgen_global_stop_count;
161 #define SGEN_ALIGN_UP_TO(val,align) (((val) + (align - 1)) & ~(align - 1))
162 #define SGEN_ALIGN_DOWN_TO(val,align) ((val) & ~(align - 1))
164 #define SGEN_ALLOC_ALIGN 8
165 #define SGEN_ALLOC_ALIGN_BITS 3
167 /* s must be non-negative */
168 #define SGEN_CAN_ALIGN_UP(s) ((s) <= SIZE_MAX - (SGEN_ALLOC_ALIGN - 1))
169 #define SGEN_ALIGN_UP(s) SGEN_ALIGN_UP_TO(s, SGEN_ALLOC_ALIGN)
170 #define SGEN_ALIGN_DOWN(s) SGEN_ALIGN_DOWN_TO(s, SGEN_ALLOC_ALIGN)
172 #if SIZEOF_VOID_P == 4
179 sgen_aligned_addr_hash (gconstpointer ptr)
181 return GPOINTER_TO_UINT (ptr) >> 3;
184 #define SGEN_PTR_IN_NURSERY(p,bits,start,end) (((mword)(p) & ~(((mword)1 << (bits)) - 1)) == (mword)(start))
186 extern size_t sgen_nursery_size;
187 extern int sgen_nursery_bits;
189 extern char *sgen_nursery_start;
190 extern char *sgen_nursery_end;
192 static inline MONO_ALWAYS_INLINE gboolean
193 sgen_ptr_in_nursery (void *p)
195 return SGEN_PTR_IN_NURSERY ((p), sgen_nursery_bits, sgen_nursery_start, sgen_nursery_end);
198 static inline MONO_ALWAYS_INLINE char*
199 sgen_get_nursery_start (void)
201 return sgen_nursery_start;
204 static inline MONO_ALWAYS_INLINE char*
205 sgen_get_nursery_end (void)
207 return sgen_nursery_end;
211 * We use the lowest three bits in the vtable pointer of objects to tag whether they're
212 * forwarded, pinned, and/or cemented. These are the valid states:
215 * |------------------+------+
217 * | forwarded | 001 |
219 * | pinned, cemented | 110 |
221 * We store them in the vtable slot because the bits are used in the sync block for other
222 * purposes: if we merge them and alloc the sync blocks aligned to 8 bytes, we can change
223 * this and use bit 3 in the syncblock (with the lower two bits both set for forwarded, that
224 * would be an invalid combination for the monitor and hash code).
227 #include "sgen-tagged-pointer.h"
229 #define SGEN_VTABLE_BITS_MASK SGEN_TAGGED_POINTER_MASK
231 #define SGEN_POINTER_IS_TAGGED_FORWARDED(p) SGEN_POINTER_IS_TAGGED_1((p))
232 #define SGEN_POINTER_TAG_FORWARDED(p) SGEN_POINTER_TAG_1((p))
234 #define SGEN_POINTER_IS_TAGGED_PINNED(p) SGEN_POINTER_IS_TAGGED_2((p))
235 #define SGEN_POINTER_TAG_PINNED(p) SGEN_POINTER_TAG_2((p))
237 #define SGEN_POINTER_IS_TAGGED_CEMENTED(p) SGEN_POINTER_IS_TAGGED_4((p))
238 #define SGEN_POINTER_TAG_CEMENTED(p) SGEN_POINTER_TAG_4((p))
240 #define SGEN_POINTER_UNTAG_VTABLE(p) SGEN_POINTER_UNTAG_ALL((p))
242 /* returns NULL if not forwarded, or the forwarded address */
243 #define SGEN_VTABLE_IS_FORWARDED(vtable) ((GCObject *)(SGEN_POINTER_IS_TAGGED_FORWARDED ((vtable)) ? SGEN_POINTER_UNTAG_VTABLE ((vtable)) : NULL))
244 #define SGEN_OBJECT_IS_FORWARDED(obj) ((GCObject *)SGEN_VTABLE_IS_FORWARDED (((mword*)(obj))[0]))
246 #define SGEN_VTABLE_IS_PINNED(vtable) SGEN_POINTER_IS_TAGGED_PINNED ((vtable))
247 #define SGEN_OBJECT_IS_PINNED(obj) (SGEN_VTABLE_IS_PINNED (((mword*)(obj))[0]))
249 #define SGEN_OBJECT_IS_CEMENTED(obj) (SGEN_POINTER_IS_TAGGED_CEMENTED (((mword*)(obj))[0]))
251 /* set the forwarded address fw_addr for object obj */
252 #define SGEN_FORWARD_OBJECT(obj,fw_addr) do { \
253 *(void**)(obj) = SGEN_POINTER_TAG_FORWARDED ((fw_addr)); \
255 #define SGEN_FORWARD_OBJECT_PAR(obj,fw_addr,final_fw_addr) do { \
256 gpointer old_vtable_word = *(gpointer*)obj; \
257 gpointer new_vtable_word; \
258 final_fw_addr = SGEN_VTABLE_IS_FORWARDED (old_vtable_word); \
261 new_vtable_word = SGEN_POINTER_TAG_FORWARDED ((fw_addr)); \
262 old_vtable_word = InterlockedCompareExchangePointer ((gpointer*)obj, new_vtable_word, old_vtable_word); \
263 final_fw_addr = SGEN_VTABLE_IS_FORWARDED (old_vtable_word); \
264 if (!final_fw_addr) \
265 final_fw_addr = (fw_addr); \
267 #define SGEN_PIN_OBJECT(obj) do { \
268 *(void**)(obj) = SGEN_POINTER_TAG_PINNED (*(void**)(obj)); \
270 #define SGEN_CEMENT_OBJECT(obj) do { \
271 *(void**)(obj) = SGEN_POINTER_TAG_CEMENTED (*(void**)(obj)); \
273 /* Unpins and uncements */
274 #define SGEN_UNPIN_OBJECT(obj) do { \
275 *(void**)(obj) = SGEN_POINTER_UNTAG_VTABLE (*(void**)(obj)); \
279 * Since we set bits in the vtable, use the macro to load it from the pointer to
280 * an object that is potentially pinned.
282 #define SGEN_LOAD_VTABLE(obj) ((GCVTable)(SGEN_POINTER_UNTAG_ALL (SGEN_LOAD_VTABLE_UNCHECKED ((GCObject *)(obj)))))
285 List of what each bit on of the vtable gc bits means.
288 // When the Java bridge has determined an object is "bridged", it uses these two bits to cache that information.
289 SGEN_GC_BIT_BRIDGE_OBJECT = 1,
290 SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT = 2,
291 SGEN_GC_BIT_FINALIZER_AWARE = 4,
294 void sgen_gc_init (void);
296 void sgen_os_init (void);
298 void sgen_update_heap_boundaries (mword low, mword high);
300 void sgen_check_section_scan_starts (GCMemSection *section);
302 void sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type);
304 gboolean sgen_gc_initialized (void);
306 /* Keep in sync with description_for_type() in sgen-internal.c! */
308 INTERNAL_MEM_PIN_QUEUE,
309 INTERNAL_MEM_FRAGMENT,
310 INTERNAL_MEM_SECTION,
311 INTERNAL_MEM_SCAN_STARTS,
312 INTERNAL_MEM_FIN_TABLE,
313 INTERNAL_MEM_FINALIZE_ENTRY,
314 INTERNAL_MEM_FINALIZE_READY,
315 INTERNAL_MEM_DISLINK_TABLE,
316 INTERNAL_MEM_DISLINK,
317 INTERNAL_MEM_ROOTS_TABLE,
318 INTERNAL_MEM_ROOT_RECORD,
319 INTERNAL_MEM_STATISTICS,
320 INTERNAL_MEM_STAT_PINNED_CLASS,
321 INTERNAL_MEM_STAT_REMSET_CLASS,
322 INTERNAL_MEM_GRAY_QUEUE,
323 INTERNAL_MEM_MS_TABLES,
324 INTERNAL_MEM_MS_BLOCK_INFO,
325 INTERNAL_MEM_MS_BLOCK_INFO_SORT,
326 INTERNAL_MEM_WORKER_DATA,
327 INTERNAL_MEM_THREAD_POOL_JOB,
328 INTERNAL_MEM_BRIDGE_DATA,
329 INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE,
330 INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE_ENTRY,
331 INTERNAL_MEM_BRIDGE_HASH_TABLE,
332 INTERNAL_MEM_BRIDGE_HASH_TABLE_ENTRY,
333 INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE,
334 INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE_ENTRY,
335 INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE,
336 INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE_ENTRY,
337 INTERNAL_MEM_TARJAN_OBJ_BUCKET,
338 INTERNAL_MEM_BRIDGE_DEBUG,
339 INTERNAL_MEM_TOGGLEREF_DATA,
340 INTERNAL_MEM_CARDTABLE_MOD_UNION,
341 INTERNAL_MEM_BINARY_PROTOCOL,
342 INTERNAL_MEM_TEMPORARY,
343 INTERNAL_MEM_LOG_ENTRY,
344 INTERNAL_MEM_COMPLEX_DESCRIPTORS,
345 INTERNAL_MEM_FIRST_CLIENT
354 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
355 #define BINARY_PROTOCOL_ARG(x) ,x
357 #define BINARY_PROTOCOL_ARG(x)
360 void sgen_init_internal_allocator (void);
362 #define SGEN_DEFINE_OBJECT_VTABLE
363 #ifdef SGEN_CLIENT_HEADER
364 #include SGEN_CLIENT_HEADER
366 #include "metadata/sgen-client-mono.h"
368 #undef SGEN_DEFINE_OBJECT_VTABLE
370 #include "mono/sgen/sgen-descriptor.h"
371 #include "mono/sgen/sgen-gray.h"
373 /* the runtime can register areas of memory as roots: we keep two lists of roots,
374 * a pinned root set for conservatively scanned roots and a normal one for
375 * precisely scanned roots (currently implemented as a single list).
377 typedef struct _RootRecord RootRecord;
380 SgenDescriptor root_desc;
386 ROOT_TYPE_NORMAL = 0, /* "normal" roots */
387 ROOT_TYPE_PINNED = 1, /* roots without a GC descriptor */
388 ROOT_TYPE_WBARRIER = 2, /* roots with a write barrier */
392 extern SgenHashTable roots_hash [ROOT_TYPE_NUM];
394 int sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg);
395 void sgen_deregister_root (char* addr);
397 typedef void (*IterateObjectCallbackFunc) (GCObject*, size_t, void*);
399 void sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries);
401 /* eventually share with MonoThread? */
403 * This structure extends the MonoThreadInfo structure.
405 struct _SgenThreadInfo {
406 SgenClientThreadInfo client_info;
414 gboolean sgen_is_worker_thread (MonoNativeThreadId thread);
416 typedef void (*CopyOrMarkObjectFunc) (GCObject**, SgenGrayQueue*);
417 typedef void (*ScanObjectFunc) (GCObject *obj, SgenDescriptor desc, SgenGrayQueue*);
418 typedef void (*ScanVTypeFunc) (GCObject *full_object, char *start, SgenDescriptor desc, SgenGrayQueue* BINARY_PROTOCOL_ARG (size_t size));
419 typedef void (*ScanPtrFieldFunc) (GCObject *obj, GCObject **ptr, SgenGrayQueue* queue);
420 typedef gboolean (*DrainGrayStackFunc) (SgenGrayQueue *queue);
423 CopyOrMarkObjectFunc copy_or_mark_object;
424 ScanObjectFunc scan_object;
425 ScanVTypeFunc scan_vtype;
426 ScanPtrFieldFunc scan_ptr_field;
427 /* Drain stack optimized for the above functions */
428 DrainGrayStackFunc drain_gray_stack;
429 /*FIXME add allocation function? */
430 } SgenObjectOperations;
434 SgenObjectOperations *ops;
435 SgenGrayQueue *queue;
438 #define CONTEXT_FROM_OBJECT_OPERATIONS(ops, queue) ((ScanCopyContext) { (ops), (queue) })
440 void sgen_report_internal_mem_usage (void);
441 void sgen_dump_internal_mem_usage (FILE *heap_dump_file);
442 void sgen_dump_section (GCMemSection *section, const char *type);
443 void sgen_dump_occupied (char *start, char *end, char *section_start);
445 void sgen_register_fixed_internal_mem_type (int type, size_t size);
447 void* sgen_alloc_internal (int type);
448 void sgen_free_internal (void *addr, int type);
450 void* sgen_alloc_internal_dynamic (size_t size, int type, gboolean assert_on_failure);
451 void sgen_free_internal_dynamic (void *addr, size_t size, int type);
453 void sgen_pin_stats_enable (void);
454 void sgen_pin_stats_register_object (GCObject *obj, int generation);
455 void sgen_pin_stats_register_global_remset (GCObject *obj);
456 void sgen_pin_stats_report (void);
458 void sgen_sort_addresses (void **array, size_t size);
459 void sgen_add_to_global_remset (gpointer ptr, GCObject *obj);
461 int sgen_get_current_collection_generation (void);
462 gboolean sgen_collection_is_concurrent (void);
463 gboolean sgen_concurrent_collection_in_progress (void);
465 typedef struct _SgenFragment SgenFragment;
467 struct _SgenFragment {
469 char *fragment_start;
470 char *fragment_next; /* the current soft limit for allocation */
472 SgenFragment *next_in_order; /* We use a different entry for all active fragments so we can avoid SMR. */
476 SgenFragment *alloc_head; /* List head to be used when allocating memory. Walk with fragment_next. */
477 SgenFragment *region_head; /* List head of the region used by this allocator. Walk with next_in_order. */
478 } SgenFragmentAllocator;
480 void sgen_fragment_allocator_add (SgenFragmentAllocator *allocator, char *start, char *end);
481 void sgen_fragment_allocator_release (SgenFragmentAllocator *allocator);
482 void* sgen_fragment_allocator_par_alloc (SgenFragmentAllocator *allocator, size_t size);
483 void* sgen_fragment_allocator_serial_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
484 void* sgen_fragment_allocator_par_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
485 SgenFragment* sgen_fragment_allocator_alloc (void);
486 void sgen_clear_allocator_fragments (SgenFragmentAllocator *allocator);
487 void sgen_clear_range (char *start, char *end);
491 This is a space/speed compromise as we need to make sure the from/to space check is both O(1)
492 and only hit cache hot memory. On a 4Mb nursery it requires 1024 bytes, or 3% of your average
493 L1 cache. On small configs with a 512kb nursery, this goes to 0.4%.
495 Experimental results on how much space we waste with a 4Mb nursery:
497 Note that the wastage applies to the half nursery, or 2Mb:
499 Test 1 (compiling corlib):
504 #define SGEN_TO_SPACE_GRANULE_BITS 9
505 #define SGEN_TO_SPACE_GRANULE_IN_BYTES (1 << SGEN_TO_SPACE_GRANULE_BITS)
507 extern char *sgen_space_bitmap;
508 extern size_t sgen_space_bitmap_size;
510 static inline gboolean
511 sgen_nursery_is_to_space (void *object)
513 size_t idx = ((char*)object - sgen_nursery_start) >> SGEN_TO_SPACE_GRANULE_BITS;
514 size_t byte = idx >> 3;
515 size_t bit = idx & 0x7;
517 SGEN_ASSERT (4, sgen_ptr_in_nursery (object), "object %p is not in nursery [%p - %p]", object, sgen_get_nursery_start (), sgen_get_nursery_end ());
518 SGEN_ASSERT (4, byte < sgen_space_bitmap_size, "byte index %zd out of range (%zd)", byte, sgen_space_bitmap_size);
520 return (sgen_space_bitmap [byte] & (1 << bit)) != 0;
523 static inline gboolean
524 sgen_nursery_is_from_space (void *object)
526 return !sgen_nursery_is_to_space (object);
529 static inline gboolean
530 sgen_nursery_is_object_alive (GCObject *obj)
532 /* FIXME put this asserts under a non default level */
533 g_assert (sgen_ptr_in_nursery (obj));
535 if (sgen_nursery_is_to_space (obj))
538 if (SGEN_OBJECT_IS_PINNED (obj) || SGEN_OBJECT_IS_FORWARDED (obj))
546 gboolean is_parallel;
548 GCObject* (*alloc_for_promotion) (GCVTable vtable, GCObject *obj, size_t objsize, gboolean has_references);
550 SgenObjectOperations serial_ops;
551 SgenObjectOperations serial_ops_with_concurrent_major;
552 SgenObjectOperations parallel_ops;
554 void (*prepare_to_space) (char *to_space_bitmap, size_t space_bitmap_size);
555 void (*clear_fragments) (void);
556 SgenFragment* (*build_fragments_get_exclude_head) (void);
557 void (*build_fragments_release_exclude_head) (void);
558 void (*build_fragments_finish) (SgenFragmentAllocator *allocator);
559 void (*init_nursery) (SgenFragmentAllocator *allocator, char *start, char *end);
561 gboolean (*handle_gc_param) (const char *opt); /* Optional */
562 void (*print_gc_param_usage) (void); /* Optional */
563 } SgenMinorCollector;
565 extern SgenMinorCollector sgen_minor_collector;
567 void sgen_simple_nursery_init (SgenMinorCollector *collector, gboolean parallel);
568 void sgen_split_nursery_init (SgenMinorCollector *collector);
570 /* Updating references */
572 #ifdef SGEN_CHECK_UPDATE_REFERENCE
573 gboolean sgen_thread_pool_is_thread_pool_thread (MonoNativeThreadId some_thread);
576 sgen_update_reference (GCObject **p, GCObject *o, gboolean allow_null)
579 SGEN_ASSERT (0, o, "Cannot update a reference with a NULL pointer");
580 SGEN_ASSERT (0, !sgen_workers_is_worker_thread (mono_native_thread_id_get ()), "Can't update a reference in the worker thread");
584 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o) sgen_update_reference ((GCObject**)(p), (GCObject*)(o), TRUE)
585 #define SGEN_UPDATE_REFERENCE(p,o) sgen_update_reference ((GCObject**)(p), (GCObject*)(o), FALSE)
587 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o) (*(GCObject**)(p) = (GCObject*)(o))
588 #define SGEN_UPDATE_REFERENCE(p,o) SGEN_UPDATE_REFERENCE_ALLOW_NULL ((p), (o))
591 /* Major collector */
593 typedef void (*sgen_cardtable_block_callback) (mword start, mword size);
594 void sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
595 void sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback);
598 ITERATE_OBJECTS_SWEEP = 1,
599 ITERATE_OBJECTS_NON_PINNED = 2,
600 ITERATE_OBJECTS_PINNED = 4,
601 ITERATE_OBJECTS_SWEEP_NON_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED,
602 ITERATE_OBJECTS_SWEEP_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_PINNED,
603 ITERATE_OBJECTS_SWEEP_ALL = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED | ITERATE_OBJECTS_PINNED
604 } IterateObjectsFlags;
608 size_t num_scanned_objects;
609 size_t num_unique_scanned_objects;
610 } ScannedObjectCounts;
613 CARDTABLE_SCAN_GLOBAL = 0,
614 CARDTABLE_SCAN_MOD_UNION = 1,
615 CARDTABLE_SCAN_MOD_UNION_PRECLEAN = CARDTABLE_SCAN_MOD_UNION | 2,
618 typedef struct _SgenMajorCollector SgenMajorCollector;
619 struct _SgenMajorCollector {
621 gboolean is_concurrent;
622 gboolean is_parallel;
623 gboolean supports_cardtable;
624 gboolean sweeps_lazily;
626 void* (*alloc_heap) (mword nursery_size, mword nursery_align, int nursery_bits);
627 gboolean (*is_object_live) (GCObject *obj);
628 GCObject* (*alloc_small_pinned_obj) (GCVTable vtable, size_t size, gboolean has_references);
629 GCObject* (*alloc_degraded) (GCVTable vtable, size_t size);
631 SgenObjectOperations major_ops_serial;
632 SgenObjectOperations major_ops_concurrent_start;
633 SgenObjectOperations major_ops_concurrent_finish;
634 SgenObjectOperations major_ops_conc_par_start;
635 SgenObjectOperations major_ops_conc_par_finish;
637 GCObject* (*alloc_object) (GCVTable vtable, size_t size, gboolean has_references);
638 GCObject* (*alloc_object_par) (GCVTable vtable, size_t size, gboolean has_references);
639 void (*free_pinned_object) (GCObject *obj, size_t size);
642 * This is used for domain unloading, heap walking from the logging profiler, and
643 * debugging. Can assume the world is stopped.
645 void (*iterate_objects) (IterateObjectsFlags flags, IterateObjectCallbackFunc callback, void *data);
647 void (*free_non_pinned_object) (GCObject *obj, size_t size);
648 void (*pin_objects) (SgenGrayQueue *queue);
649 void (*pin_major_object) (GCObject *obj, SgenGrayQueue *queue);
650 void (*scan_card_table) (CardTableScanType scan_type, ScanCopyContext ctx, int job_index, int job_split_count);
651 void (*iterate_live_block_ranges) (sgen_cardtable_block_callback callback);
652 void (*iterate_block_ranges) (sgen_cardtable_block_callback callback);
653 void (*update_cardtable_mod_union) (void);
654 void (*init_to_space) (void);
655 void (*sweep) (void);
656 gboolean (*have_swept) (void);
657 void (*finish_sweeping) (void);
658 void (*free_swept_blocks) (size_t section_reserve);
659 void (*check_scan_starts) (void);
660 void (*dump_heap) (FILE *heap_dump_file);
661 gint64 (*get_used_size) (void);
662 void (*start_nursery_collection) (void);
663 void (*finish_nursery_collection) (void);
664 void (*start_major_collection) (void);
665 void (*finish_major_collection) (ScannedObjectCounts *counts);
666 gboolean (*ptr_is_in_non_pinned_space) (char *ptr, char **start);
667 gboolean (*ptr_is_from_pinned_alloc) (char *ptr);
668 void (*report_pinned_memory_usage) (void);
669 size_t (*get_num_major_sections) (void);
670 size_t (*get_bytes_survived_last_sweep) (void);
671 gboolean (*handle_gc_param) (const char *opt);
672 void (*print_gc_param_usage) (void);
673 void (*post_param_init) (SgenMajorCollector *collector);
674 gboolean (*is_valid_object) (char *ptr);
675 GCVTable (*describe_pointer) (char *pointer);
676 guint8* (*get_cardtable_mod_union_for_reference) (char *object);
677 long long (*get_and_reset_num_major_objects_marked) (void);
678 void (*count_cards) (long long *num_total_cards, long long *num_marked_cards);
679 SgenThreadPool* (*get_sweep_pool) (void);
681 void (*worker_init_cb) (gpointer worker);
684 extern SgenMajorCollector major_collector;
686 void sgen_marksweep_init (SgenMajorCollector *collector);
687 void sgen_marksweep_conc_init (SgenMajorCollector *collector);
688 void sgen_marksweep_conc_par_init (SgenMajorCollector *collector);
689 SgenMajorCollector* sgen_get_major_collector (void);
690 SgenMinorCollector* sgen_get_minor_collector (void);
693 typedef struct _SgenRememberedSet {
694 void (*wbarrier_set_field) (GCObject *obj, gpointer field_ptr, GCObject* value);
695 void (*wbarrier_arrayref_copy) (gpointer dest_ptr, gpointer src_ptr, int count);
696 void (*wbarrier_value_copy) (gpointer dest, gpointer src, int count, size_t element_size);
697 void (*wbarrier_object_copy) (GCObject* obj, GCObject *src);
698 void (*wbarrier_generic_nostore) (gpointer ptr);
699 void (*record_pointer) (gpointer ptr);
700 void (*wbarrier_range_copy) (gpointer dest, gpointer src, int count);
702 void (*start_scan_remsets) (void);
704 void (*clear_cards) (void);
706 gboolean (*find_address) (char *addr);
707 gboolean (*find_address_with_cards) (char *cards_start, guint8 *cards, char *addr);
710 SgenRememberedSet *sgen_get_remset (void);
713 * These must be kept in sync with object.h. They're here for using SGen independently of
716 void mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count);
717 void mono_gc_wbarrier_generic_nostore (gpointer ptr);
718 void mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value);
719 void mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value);
721 void sgen_wbarrier_range_copy (gpointer _dest, gpointer _src, int size);
723 static inline SgenDescriptor
724 sgen_obj_get_descriptor (GCObject *obj)
726 GCVTable vtable = SGEN_LOAD_VTABLE_UNCHECKED (obj);
727 SGEN_ASSERT (9, !SGEN_POINTER_IS_TAGGED_ANY (vtable), "Object can't be tagged");
728 return sgen_vtable_get_descriptor (vtable);
731 static inline SgenDescriptor
732 sgen_obj_get_descriptor_safe (GCObject *obj)
734 GCVTable vtable = SGEN_LOAD_VTABLE (obj);
735 return sgen_vtable_get_descriptor (vtable);
738 static mword sgen_client_par_object_get_size (GCVTable vtable, GCObject* o);
739 static mword sgen_client_slow_object_get_size (GCVTable vtable, GCObject* o);
742 sgen_safe_object_get_size (GCObject *obj)
745 GCVTable vtable = SGEN_LOAD_VTABLE_UNCHECKED (obj);
748 * Once we load the vtable, we must always use it, in case we are in parallel case.
749 * Otherwise the object might get forwarded in the meantime and we would read an
750 * invalid vtable. An object cannot be forwarded for a second time during same GC.
752 if ((forwarded = SGEN_VTABLE_IS_FORWARDED (vtable)))
753 return sgen_client_par_object_get_size (SGEN_LOAD_VTABLE (forwarded), obj);
755 return sgen_client_par_object_get_size ((GCVTable)SGEN_POINTER_UNTAG_ALL (vtable), obj);
758 static inline gboolean
759 sgen_safe_object_is_small (GCObject *obj, int type)
761 if (type <= DESC_TYPE_MAX_SMALL_OBJ)
763 return SGEN_ALIGN_UP (sgen_safe_object_get_size ((GCObject*)obj)) <= SGEN_MAX_SMALL_OBJ_SIZE;
767 * This variant guarantees to return the exact size of the object
768 * before alignment. Needed for canary support.
771 sgen_safe_object_get_size_unaligned (GCObject *obj)
775 if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
776 obj = (GCObject*)forwarded;
779 return sgen_client_slow_object_get_size (SGEN_LOAD_VTABLE (obj), obj);
782 #ifdef SGEN_CLIENT_HEADER
783 #include SGEN_CLIENT_HEADER
785 #include "metadata/sgen-client-mono.h"
788 gboolean sgen_object_is_live (GCObject *obj);
790 void sgen_init_fin_weak_hash (void);
792 /* FIXME: move the toggleref stuff out of here */
793 void sgen_mark_togglerefs (char *start, char *end, ScanCopyContext ctx);
794 void sgen_clear_togglerefs (char *start, char *end, ScanCopyContext ctx);
796 void sgen_process_togglerefs (void);
797 void sgen_register_test_toggleref_callback (void);
799 void sgen_mark_bridge_object (GCObject *obj);
800 void sgen_collect_bridge_objects (int generation, ScanCopyContext ctx);
802 typedef gboolean (*SgenObjectPredicateFunc) (GCObject *obj, void *user_data);
804 void sgen_null_links_if (SgenObjectPredicateFunc predicate, void *data, int generation, gboolean track);
806 gboolean sgen_gc_is_object_ready_for_finalization (GCObject *object);
807 void sgen_gc_lock (void);
808 void sgen_gc_unlock (void);
810 void sgen_queue_finalization_entry (GCObject *obj);
811 const char* sgen_generation_name (int generation);
813 void sgen_finalize_in_range (int generation, ScanCopyContext ctx);
814 void sgen_null_link_in_range (int generation, ScanCopyContext ctx, gboolean track);
815 void sgen_process_fin_stage_entries (void);
816 gboolean sgen_have_pending_finalizers (void);
817 void sgen_object_register_for_finalization (GCObject *obj, void *user_data);
819 void sgen_finalize_if (SgenObjectPredicateFunc predicate, void *user_data);
820 void sgen_remove_finalizers_if (SgenObjectPredicateFunc predicate, void *user_data, int generation);
821 void sgen_set_suspend_finalizers (void);
823 void sgen_wbroots_iterate_live_block_ranges (sgen_cardtable_block_callback cb);
824 void sgen_wbroots_scan_card_table (ScanCopyContext ctx);
826 void sgen_register_disappearing_link (GCObject *obj, void **link, gboolean track, gboolean in_gc);
828 GCObject* sgen_weak_link_get (void **link_addr);
830 gboolean sgen_drain_gray_stack (ScanCopyContext ctx);
838 void sgen_pin_object (GCObject *object, SgenGrayQueue *queue);
839 void sgen_set_pinned_from_failed_allocation (mword objsize);
841 void sgen_ensure_free_space (size_t size, int generation);
842 void sgen_gc_collect (int generation);
843 void sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw);
845 int sgen_gc_collection_count (int generation);
846 /* FIXME: what exactly does this return? */
847 size_t sgen_gc_get_used_size (void);
848 size_t sgen_gc_get_total_heap_allocation (void);
852 void sgen_stop_world (int generation);
853 void sgen_restart_world (int generation);
854 gboolean sgen_is_world_stopped (void);
856 gboolean sgen_set_allow_synchronous_major (gboolean flag);
860 typedef struct _LOSObject LOSObject;
863 mword size; /* this is the object size, lowest bit used for pin/mark */
864 guint8 * volatile cardtable_mod_union; /* only used by the concurrent collector */
865 #if SIZEOF_VOID_P < 8
866 mword dummy; /* to align object to sizeof (double) */
868 GCObject data [MONO_ZERO_LEN_ARRAY];
871 extern LOSObject *los_object_list;
872 extern mword los_memory_usage;
873 extern mword los_memory_usage_total;
875 void sgen_los_free_object (LOSObject *obj);
876 void* sgen_los_alloc_large_inner (GCVTable vtable, size_t size);
877 void sgen_los_sweep (void);
878 gboolean sgen_ptr_is_in_los (char *ptr, char **start);
879 void sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data);
880 void sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
881 void sgen_los_scan_card_table (CardTableScanType scan_type, ScanCopyContext ctx, int job_index, int job_split_count);
882 void sgen_los_update_cardtable_mod_union (void);
883 void sgen_los_count_cards (long long *num_total_cards, long long *num_marked_cards);
884 gboolean sgen_los_is_valid_object (char *object);
885 gboolean mono_sgen_los_describe_pointer (char *ptr);
886 LOSObject* sgen_los_header_for_object (GCObject *data);
887 mword sgen_los_object_size (LOSObject *obj);
888 void sgen_los_pin_object (GCObject *obj);
889 gboolean sgen_los_pin_object_par (GCObject *obj);
890 gboolean sgen_los_object_is_pinned (GCObject *obj);
891 void sgen_los_mark_mod_union_card (GCObject *mono_obj, void **ptr);
894 /* nursery allocator */
896 void sgen_clear_nursery_fragments (void);
897 void sgen_nursery_allocator_prepare_for_pinning (void);
898 void sgen_nursery_allocator_set_nursery_bounds (char *nursery_start, char *nursery_end);
899 mword sgen_build_nursery_fragments (GCMemSection *nursery_section, SgenGrayQueue *unpin_queue);
900 void sgen_init_nursery_allocator (void);
901 void sgen_nursery_allocator_init_heavy_stats (void);
902 void sgen_init_allocator (void);
903 void* sgen_nursery_alloc (size_t size);
904 void* sgen_nursery_alloc_range (size_t size, size_t min_size, size_t *out_alloc_size);
905 gboolean sgen_can_alloc_size (size_t size);
906 void sgen_nursery_retire_region (void *address, ptrdiff_t size);
908 void sgen_nursery_alloc_prepare_for_minor (void);
909 void sgen_nursery_alloc_prepare_for_major (void);
911 GCObject* sgen_alloc_for_promotion (GCObject *obj, size_t objsize, gboolean has_references);
913 GCObject* sgen_alloc_obj_nolock (GCVTable vtable, size_t size);
914 GCObject* sgen_try_alloc_obj_nolock (GCVTable vtable, size_t size);
918 void* sgen_thread_register (SgenThreadInfo* info, void *addr);
919 void sgen_thread_unregister (SgenThreadInfo *p);
921 /* Finalization/ephemeron support */
923 static inline gboolean
924 sgen_major_is_object_alive (GCObject *object)
928 /* Oldgen objects can be pinned and forwarded too */
929 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
933 * FIXME: major_collector.is_object_live() also calculates the
934 * size. Avoid the double calculation.
936 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size (object));
937 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
938 return sgen_los_object_is_pinned (object);
940 return major_collector.is_object_live (object);
944 * This function returns true if @object is either alive or it belongs to the old gen
945 * and we're currently doing a minor collection.
948 sgen_is_object_alive_for_current_gen (GCObject *object)
950 if (sgen_ptr_in_nursery (object))
951 return sgen_nursery_is_object_alive (object);
953 if (current_collection_generation == GENERATION_NURSERY)
956 return sgen_major_is_object_alive (object);
959 int sgen_gc_invoke_finalizers (void);
963 void sgen_init_gchandles (void);
965 void sgen_null_links_if (SgenObjectPredicateFunc predicate, void *data, int generation, gboolean track);
967 typedef gpointer (*SgenGCHandleIterateCallback) (gpointer hidden, GCHandleType handle_type, int max_generation, gpointer user);
969 void sgen_gchandle_iterate (GCHandleType handle_type, int max_generation, SgenGCHandleIterateCallback callback, gpointer user);
970 void sgen_gchandle_set_target (guint32 gchandle, GCObject *obj);
971 void sgen_mark_normal_gc_handles (void *addr, SgenUserMarkFunc mark_func, void *gc_data);
972 gpointer sgen_gchandle_get_metadata (guint32 gchandle);
976 extern GCMemSection *nursery_section;
977 extern guint32 collect_before_allocs;
978 extern guint32 verify_before_allocs;
979 extern gboolean has_per_allocation_action;
980 extern size_t degraded_mode;
981 extern int default_nursery_size;
982 extern guint32 tlab_size;
983 extern NurseryClearPolicy nursery_clear_policy;
984 extern gboolean sgen_try_free_some_memory;
985 extern mword total_promoted_size;
986 extern mword total_allocated_major;
987 extern volatile gboolean sgen_suspend_finalizers;
988 extern MonoCoopMutex gc_mutex;
989 extern volatile gboolean concurrent_collection_in_progress;
991 /* Nursery helpers. */
994 sgen_set_nursery_scan_start (char *p)
996 size_t idx = (p - (char*)nursery_section->data) / SGEN_SCAN_START_SIZE;
997 char *old = nursery_section->scan_starts [idx];
999 nursery_section->scan_starts [idx] = p;
1003 /* Object Allocation */
1011 } SgenAllocatorType;
1013 void sgen_clear_tlabs (void);
1015 GCObject* sgen_alloc_obj (GCVTable vtable, size_t size);
1016 GCObject* sgen_alloc_obj_pinned (GCVTable vtable, size_t size);
1017 GCObject* sgen_alloc_obj_mature (GCVTable vtable, size_t size);
1021 void sgen_check_remset_consistency (void);
1022 void sgen_check_mod_union_consistency (void);
1023 void sgen_check_major_refs (void);
1024 void sgen_check_whole_heap (gboolean allow_missing_pinning);
1025 void sgen_check_whole_heap_stw (void);
1026 void sgen_check_objref (char *obj);
1027 void sgen_check_heap_marked (gboolean nursery_must_be_pinned);
1028 void sgen_check_nursery_objects_pinned (gboolean pinned);
1029 void sgen_check_for_xdomain_refs (void);
1030 GCObject* sgen_find_object_for_ptr (char *ptr);
1032 void mono_gc_scan_for_specific_ref (GCObject *key, gboolean precise);
1034 void sgen_debug_enable_heap_dump (const char *filename);
1035 void sgen_debug_dump_heap (const char *type, int num, const char *reason);
1037 void sgen_debug_verify_nursery (gboolean do_dump_nursery_content);
1038 void sgen_debug_check_nursery_is_clean (void);
1040 /* Environment variable parsing */
1042 #define MONO_GC_PARAMS_NAME "MONO_GC_PARAMS"
1043 #define MONO_GC_DEBUG_NAME "MONO_GC_DEBUG"
1045 void sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...);
1049 void sgen_qsort (void *array, size_t count, size_t element_size, int (*compare) (const void*, const void*));
1050 gint64 sgen_timestamp (void);
1053 * Canary (guard word) support
1055 * - CANARY_SIZE must be multiple of word size in bytes
1056 * - Canary space is not included on checks against SGEN_MAX_SMALL_OBJ_SIZE
1059 gboolean nursery_canaries_enabled (void);
1061 #define CANARY_SIZE 8
1062 #define CANARY_STRING "koupepia"
1064 #define CANARIFY_SIZE(size) if (nursery_canaries_enabled ()) { \
1065 size = size + CANARY_SIZE; \
1068 #define CANARIFY_ALLOC(addr,size) if (nursery_canaries_enabled ()) { \
1069 memcpy ((char*) (addr) + (size), CANARY_STRING, CANARY_SIZE); \
1072 #define CANARY_VALID(addr) (strncmp ((char*) (addr), CANARY_STRING, CANARY_SIZE) == 0)
1074 #define CHECK_CANARY_FOR_OBJECT(addr,fail) if (nursery_canaries_enabled ()) { \
1075 guint size = sgen_safe_object_get_size_unaligned ((GCObject *) (addr)); \
1076 char* canary_ptr = (char*) (addr) + size; \
1077 if (!CANARY_VALID(canary_ptr)) { \
1078 char *window_start, *window_end; \
1079 window_start = (char*)(addr) - 128; \
1080 if (!sgen_ptr_in_nursery (window_start)) \
1081 window_start = sgen_get_nursery_start (); \
1082 window_end = (char*)(addr) + 128; \
1083 if (!sgen_ptr_in_nursery (window_end)) \
1084 window_end = sgen_get_nursery_end (); \
1085 fprintf (stderr, "\nCANARY ERROR - Type:%s Size:%d Address:%p Data:\n", sgen_client_vtable_get_name (SGEN_LOAD_VTABLE ((addr))), size, (char*) addr); \
1086 fwrite (addr, sizeof (char), size, stderr); \
1087 fprintf (stderr, "\nCanary zone (next 12 chars):\n"); \
1088 fwrite (canary_ptr, sizeof (char), 12, stderr); \
1089 fprintf (stderr, "\nOriginal canary string:\n"); \
1090 fwrite (CANARY_STRING, sizeof (char), 8, stderr); \
1091 for (int x = -8; x <= 8; x++) { \
1092 if (canary_ptr + x < (char*) addr); \
1094 if (CANARY_VALID(canary_ptr +x)) \
1095 fprintf (stderr, "\nCANARY ERROR - canary found at offset %d\n", x); \
1097 fprintf (stderr, "\nSurrounding nursery (%p - %p):\n", window_start, window_end); \
1098 fwrite (window_start, sizeof (char), window_end - window_start, stderr); \
1102 * This causes the compile to extend the liveness of 'v' till the call to dummy_use
1105 sgen_dummy_use (gpointer v)
1107 #if defined(__GNUC__)
1108 __asm__ volatile ("" : "=r"(v) : "r"(v));
1109 #elif defined(_MSC_VER)
1110 static volatile gpointer ptr;
1113 #error "Implement sgen_dummy_use for your compiler"
1117 #endif /* HAVE_SGEN_GC */
1119 #endif /* __MONO_SGENGC_H__ */