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 {
64 /* pointer where more data could be allocated if it fits */
68 * scan starts is an array of pointers to objects equally spaced in the allocation area
69 * They let use quickly find pinned objects from pinning pointers.
72 /* in major collections indexes in the pin_queue for objects that pin this section */
73 size_t pin_queue_first_entry;
74 size_t pin_queue_last_entry;
75 size_t num_scan_start;
79 * Recursion is not allowed for the thread lock.
81 #define LOCK_DECLARE(name) mono_mutex_t name
82 /* if changing LOCK_INIT to something that isn't idempotent, look at
83 its use in mono_gc_base_init in sgen-gc.c */
84 #define LOCK_INIT(name) mono_os_mutex_init (&(name))
85 #define LOCK_GC do { sgen_gc_lock (); } while (0)
86 #define UNLOCK_GC do { sgen_gc_unlock (); } while (0)
88 extern MonoCoopMutex sgen_interruption_mutex;
90 #define LOCK_INTERRUPTION mono_coop_mutex_lock (&sgen_interruption_mutex)
91 #define UNLOCK_INTERRUPTION mono_coop_mutex_unlock (&sgen_interruption_mutex)
93 /* FIXME: Use InterlockedAdd & InterlockedAdd64 to reduce the CAS cost. */
94 #define SGEN_CAS InterlockedCompareExchange
95 #define SGEN_CAS_PTR InterlockedCompareExchangePointer
96 #define SGEN_ATOMIC_ADD(x,i) do { \
100 } while (InterlockedCompareExchange (&(x), __old_x + (i), __old_x) != __old_x); \
102 #define SGEN_ATOMIC_ADD_P(x,i) do { \
106 } while (InterlockedCompareExchangePointer ((void**)&(x), (void*)(__old_x + (i)), (void*)__old_x) != (void*)__old_x); \
109 #ifdef HEAVY_STATISTICS
110 extern guint64 stat_objects_alloced_degraded;
111 extern guint64 stat_bytes_alloced_degraded;
112 extern guint64 stat_copy_object_called_major;
113 extern guint64 stat_objects_copied_major;
116 #define SGEN_ASSERT(level, a, ...) do { \
117 if (G_UNLIKELY ((level) <= SGEN_MAX_ASSERT_LEVEL && !(a))) { \
118 g_error (__VA_ARGS__); \
121 #ifdef HAVE_LOCALTIME_R
122 # define LOG_TIMESTAMP \
127 localtime_r(&t, &tod); \
128 strftime(logTime, sizeof(logTime), "%Y-%m-%d %H:%M:%S", &tod); \
131 # define LOG_TIMESTAMP \
136 tod = localtime(&t); \
137 strftime(logTime, sizeof(logTime), "%F %T", tod); \
141 #define SGEN_LOG(level, format, ...) do { \
142 if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) { \
145 mono_gc_printf (gc_debug_file, "%s " format "\n", logTime, ##__VA_ARGS__); \
148 #define SGEN_COND_LOG(level, cond, format, ...) do { \
149 if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) { \
153 mono_gc_printf (gc_debug_file, "%s " format "\n", logTime, ##__VA_ARGS__); \
157 extern int gc_debug_level;
158 extern FILE* gc_debug_file;
160 extern int current_collection_generation;
162 extern unsigned int sgen_global_stop_count;
164 #define SGEN_ALIGN_UP_TO(val,align) (((val) + (align - 1)) & ~(align - 1))
165 #define SGEN_ALIGN_DOWN_TO(val,align) ((val) & ~(align - 1))
167 #define SGEN_ALLOC_ALIGN 8
168 #define SGEN_ALLOC_ALIGN_BITS 3
170 /* s must be non-negative */
171 #define SGEN_CAN_ALIGN_UP(s) ((s) <= SIZE_MAX - (SGEN_ALLOC_ALIGN - 1))
172 #define SGEN_ALIGN_UP(s) SGEN_ALIGN_UP_TO(s, SGEN_ALLOC_ALIGN)
173 #define SGEN_ALIGN_DOWN(s) SGEN_ALIGN_DOWN_TO(s, SGEN_ALLOC_ALIGN)
175 #if SIZEOF_VOID_P == 4
182 sgen_aligned_addr_hash (gconstpointer ptr)
184 return GPOINTER_TO_UINT (ptr) >> 3;
187 #define SGEN_PTR_IN_NURSERY(p,bits,start,end) (((mword)(p) & ~(((mword)1 << (bits)) - 1)) == (mword)(start))
191 /* good sizes are 512KB-1MB: larger ones increase a lot memzeroing time */
192 #define DEFAULT_NURSERY_SIZE (sgen_nursery_size)
193 extern size_t sgen_nursery_size;
194 /* The number of trailing 0 bits in DEFAULT_NURSERY_SIZE */
195 #define DEFAULT_NURSERY_BITS (sgen_nursery_bits)
196 extern int sgen_nursery_bits;
200 #define DEFAULT_NURSERY_SIZE (4*1024*1024)
201 #define DEFAULT_NURSERY_BITS 22
205 extern char *sgen_nursery_start;
206 extern char *sgen_nursery_end;
208 static inline MONO_ALWAYS_INLINE gboolean
209 sgen_ptr_in_nursery (void *p)
211 return SGEN_PTR_IN_NURSERY ((p), DEFAULT_NURSERY_BITS, sgen_nursery_start, sgen_nursery_end);
214 static inline MONO_ALWAYS_INLINE char*
215 sgen_get_nursery_start (void)
217 return sgen_nursery_start;
220 static inline MONO_ALWAYS_INLINE char*
221 sgen_get_nursery_end (void)
223 return sgen_nursery_end;
227 * We use the lowest three bits in the vtable pointer of objects to tag whether they're
228 * forwarded, pinned, and/or cemented. These are the valid states:
231 * |------------------+------+
233 * | forwarded | 001 |
235 * | pinned, cemented | 110 |
237 * We store them in the vtable slot because the bits are used in the sync block for other
238 * purposes: if we merge them and alloc the sync blocks aligned to 8 bytes, we can change
239 * this and use bit 3 in the syncblock (with the lower two bits both set for forwarded, that
240 * would be an invalid combination for the monitor and hash code).
243 #include "sgen-tagged-pointer.h"
245 #define SGEN_VTABLE_BITS_MASK SGEN_TAGGED_POINTER_MASK
247 #define SGEN_POINTER_IS_TAGGED_FORWARDED(p) SGEN_POINTER_IS_TAGGED_1((p))
248 #define SGEN_POINTER_TAG_FORWARDED(p) SGEN_POINTER_TAG_1((p))
250 #define SGEN_POINTER_IS_TAGGED_PINNED(p) SGEN_POINTER_IS_TAGGED_2((p))
251 #define SGEN_POINTER_TAG_PINNED(p) SGEN_POINTER_TAG_2((p))
253 #define SGEN_POINTER_IS_TAGGED_CEMENTED(p) SGEN_POINTER_IS_TAGGED_4((p))
254 #define SGEN_POINTER_TAG_CEMENTED(p) SGEN_POINTER_TAG_4((p))
256 #define SGEN_POINTER_UNTAG_VTABLE(p) SGEN_POINTER_UNTAG_ALL((p))
258 /* returns NULL if not forwarded, or the forwarded address */
259 #define SGEN_VTABLE_IS_FORWARDED(vtable) ((GCObject *)(SGEN_POINTER_IS_TAGGED_FORWARDED ((vtable)) ? SGEN_POINTER_UNTAG_VTABLE ((vtable)) : NULL))
260 #define SGEN_OBJECT_IS_FORWARDED(obj) ((GCObject *)SGEN_VTABLE_IS_FORWARDED (((mword*)(obj))[0]))
262 #define SGEN_VTABLE_IS_PINNED(vtable) SGEN_POINTER_IS_TAGGED_PINNED ((vtable))
263 #define SGEN_OBJECT_IS_PINNED(obj) (SGEN_VTABLE_IS_PINNED (((mword*)(obj))[0]))
265 #define SGEN_OBJECT_IS_CEMENTED(obj) (SGEN_POINTER_IS_TAGGED_CEMENTED (((mword*)(obj))[0]))
267 /* set the forwarded address fw_addr for object obj */
268 #define SGEN_FORWARD_OBJECT(obj,fw_addr) do { \
269 *(void**)(obj) = SGEN_POINTER_TAG_FORWARDED ((fw_addr)); \
271 #define SGEN_FORWARD_OBJECT_PAR(obj,fw_addr,final_fw_addr) do { \
272 gpointer old_vtable_word = *(gpointer*)obj; \
273 gpointer new_vtable_word; \
274 final_fw_addr = SGEN_VTABLE_IS_FORWARDED (old_vtable_word); \
277 new_vtable_word = SGEN_POINTER_TAG_FORWARDED ((fw_addr)); \
278 old_vtable_word = InterlockedCompareExchangePointer ((gpointer*)obj, new_vtable_word, old_vtable_word); \
279 final_fw_addr = SGEN_VTABLE_IS_FORWARDED (old_vtable_word); \
280 if (!final_fw_addr) \
281 final_fw_addr = (fw_addr); \
283 #define SGEN_PIN_OBJECT(obj) do { \
284 *(void**)(obj) = SGEN_POINTER_TAG_PINNED (*(void**)(obj)); \
286 #define SGEN_CEMENT_OBJECT(obj) do { \
287 *(void**)(obj) = SGEN_POINTER_TAG_CEMENTED (*(void**)(obj)); \
289 /* Unpins and uncements */
290 #define SGEN_UNPIN_OBJECT(obj) do { \
291 *(void**)(obj) = SGEN_POINTER_UNTAG_VTABLE (*(void**)(obj)); \
295 * Since we set bits in the vtable, use the macro to load it from the pointer to
296 * an object that is potentially pinned.
298 #define SGEN_LOAD_VTABLE(obj) ((GCVTable)(SGEN_POINTER_UNTAG_ALL (SGEN_LOAD_VTABLE_UNCHECKED ((GCObject *)(obj)))))
301 List of what each bit on of the vtable gc bits means.
304 // When the Java bridge has determined an object is "bridged", it uses these two bits to cache that information.
305 SGEN_GC_BIT_BRIDGE_OBJECT = 1,
306 SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT = 2,
307 SGEN_GC_BIT_FINALIZER_AWARE = 4,
310 void sgen_gc_init (void);
312 void sgen_os_init (void);
314 void sgen_update_heap_boundaries (mword low, mword high);
316 void sgen_check_section_scan_starts (GCMemSection *section);
318 void sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type);
320 gboolean sgen_gc_initialized (void);
322 /* Keep in sync with description_for_type() in sgen-internal.c! */
324 INTERNAL_MEM_PIN_QUEUE,
325 INTERNAL_MEM_FRAGMENT,
326 INTERNAL_MEM_SECTION,
327 INTERNAL_MEM_SCAN_STARTS,
328 INTERNAL_MEM_FIN_TABLE,
329 INTERNAL_MEM_FINALIZE_ENTRY,
330 INTERNAL_MEM_FINALIZE_READY,
331 INTERNAL_MEM_DISLINK_TABLE,
332 INTERNAL_MEM_DISLINK,
333 INTERNAL_MEM_ROOTS_TABLE,
334 INTERNAL_MEM_ROOT_RECORD,
335 INTERNAL_MEM_STATISTICS,
336 INTERNAL_MEM_STAT_PINNED_CLASS,
337 INTERNAL_MEM_STAT_REMSET_CLASS,
338 INTERNAL_MEM_GRAY_QUEUE,
339 INTERNAL_MEM_MS_TABLES,
340 INTERNAL_MEM_MS_BLOCK_INFO,
341 INTERNAL_MEM_MS_BLOCK_INFO_SORT,
342 INTERNAL_MEM_WORKER_DATA,
343 INTERNAL_MEM_THREAD_POOL_JOB,
344 INTERNAL_MEM_BRIDGE_DATA,
345 INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE,
346 INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE_ENTRY,
347 INTERNAL_MEM_BRIDGE_HASH_TABLE,
348 INTERNAL_MEM_BRIDGE_HASH_TABLE_ENTRY,
349 INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE,
350 INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE_ENTRY,
351 INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE,
352 INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE_ENTRY,
353 INTERNAL_MEM_TARJAN_OBJ_BUCKET,
354 INTERNAL_MEM_BRIDGE_DEBUG,
355 INTERNAL_MEM_TOGGLEREF_DATA,
356 INTERNAL_MEM_CARDTABLE_MOD_UNION,
357 INTERNAL_MEM_BINARY_PROTOCOL,
358 INTERNAL_MEM_TEMPORARY,
359 INTERNAL_MEM_LOG_ENTRY,
360 INTERNAL_MEM_COMPLEX_DESCRIPTORS,
361 INTERNAL_MEM_FIRST_CLIENT
370 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
371 #define BINARY_PROTOCOL_ARG(x) ,x
373 #define BINARY_PROTOCOL_ARG(x)
376 void sgen_init_internal_allocator (void);
378 #define SGEN_DEFINE_OBJECT_VTABLE
379 #ifdef SGEN_CLIENT_HEADER
380 #include SGEN_CLIENT_HEADER
382 #include "metadata/sgen-client-mono.h"
384 #undef SGEN_DEFINE_OBJECT_VTABLE
386 #include "mono/sgen/sgen-descriptor.h"
387 #include "mono/sgen/sgen-gray.h"
389 /* the runtime can register areas of memory as roots: we keep two lists of roots,
390 * a pinned root set for conservatively scanned roots and a normal one for
391 * precisely scanned roots (currently implemented as a single list).
393 typedef struct _RootRecord RootRecord;
396 SgenDescriptor root_desc;
402 ROOT_TYPE_NORMAL = 0, /* "normal" roots */
403 ROOT_TYPE_PINNED = 1, /* roots without a GC descriptor */
404 ROOT_TYPE_WBARRIER = 2, /* roots with a write barrier */
408 extern SgenHashTable roots_hash [ROOT_TYPE_NUM];
410 int sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg);
411 void sgen_deregister_root (char* addr);
413 typedef void (*IterateObjectCallbackFunc) (GCObject*, size_t, void*);
415 void sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries);
417 /* eventually share with MonoThread? */
419 * This structure extends the MonoThreadInfo structure.
421 struct _SgenThreadInfo {
422 SgenClientThreadInfo client_info;
430 gboolean sgen_is_worker_thread (MonoNativeThreadId thread);
432 typedef void (*CopyOrMarkObjectFunc) (GCObject**, SgenGrayQueue*);
433 typedef void (*ScanObjectFunc) (GCObject *obj, SgenDescriptor desc, SgenGrayQueue*);
434 typedef void (*ScanVTypeFunc) (GCObject *full_object, char *start, SgenDescriptor desc, SgenGrayQueue* BINARY_PROTOCOL_ARG (size_t size));
435 typedef void (*ScanPtrFieldFunc) (GCObject *obj, GCObject **ptr, SgenGrayQueue* queue);
436 typedef gboolean (*DrainGrayStackFunc) (SgenGrayQueue *queue);
439 CopyOrMarkObjectFunc copy_or_mark_object;
440 ScanObjectFunc scan_object;
441 ScanVTypeFunc scan_vtype;
442 ScanPtrFieldFunc scan_ptr_field;
443 /* Drain stack optimized for the above functions */
444 DrainGrayStackFunc drain_gray_stack;
445 /*FIXME add allocation function? */
446 } SgenObjectOperations;
450 SgenObjectOperations *ops;
451 SgenGrayQueue *queue;
454 #define CONTEXT_FROM_OBJECT_OPERATIONS(ops, queue) ((ScanCopyContext) { (ops), (queue) })
456 void sgen_report_internal_mem_usage (void);
457 void sgen_dump_internal_mem_usage (FILE *heap_dump_file);
458 void sgen_dump_section (GCMemSection *section, const char *type);
459 void sgen_dump_occupied (char *start, char *end, char *section_start);
461 void sgen_register_fixed_internal_mem_type (int type, size_t size);
463 void* sgen_alloc_internal (int type);
464 void sgen_free_internal (void *addr, int type);
466 void* sgen_alloc_internal_dynamic (size_t size, int type, gboolean assert_on_failure);
467 void sgen_free_internal_dynamic (void *addr, size_t size, int type);
469 void sgen_pin_stats_enable (void);
470 void sgen_pin_stats_register_object (GCObject *obj, int generation);
471 void sgen_pin_stats_register_global_remset (GCObject *obj);
472 void sgen_pin_stats_report (void);
474 void sgen_sort_addresses (void **array, size_t size);
475 void sgen_add_to_global_remset (gpointer ptr, GCObject *obj);
477 int sgen_get_current_collection_generation (void);
478 gboolean sgen_collection_is_concurrent (void);
479 gboolean sgen_concurrent_collection_in_progress (void);
481 typedef struct _SgenFragment SgenFragment;
483 struct _SgenFragment {
485 char *fragment_start;
486 char *fragment_next; /* the current soft limit for allocation */
488 SgenFragment *next_in_order; /* We use a different entry for all active fragments so we can avoid SMR. */
492 SgenFragment *alloc_head; /* List head to be used when allocating memory. Walk with fragment_next. */
493 SgenFragment *region_head; /* List head of the region used by this allocator. Walk with next_in_order. */
494 } SgenFragmentAllocator;
496 void sgen_fragment_allocator_add (SgenFragmentAllocator *allocator, char *start, char *end);
497 void sgen_fragment_allocator_release (SgenFragmentAllocator *allocator);
498 void* sgen_fragment_allocator_serial_alloc (SgenFragmentAllocator *allocator, size_t size);
499 void* sgen_fragment_allocator_par_alloc (SgenFragmentAllocator *allocator, size_t size);
500 void* sgen_fragment_allocator_serial_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
501 void* sgen_fragment_allocator_par_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
502 SgenFragment* sgen_fragment_allocator_alloc (void);
503 void sgen_clear_allocator_fragments (SgenFragmentAllocator *allocator);
504 void sgen_clear_range (char *start, char *end);
508 This is a space/speed compromise as we need to make sure the from/to space check is both O(1)
509 and only hit cache hot memory. On a 4Mb nursery it requires 1024 bytes, or 3% of your average
510 L1 cache. On small configs with a 512kb nursery, this goes to 0.4%.
512 Experimental results on how much space we waste with a 4Mb nursery:
514 Note that the wastage applies to the half nursery, or 2Mb:
516 Test 1 (compiling corlib):
521 #define SGEN_TO_SPACE_GRANULE_BITS 9
522 #define SGEN_TO_SPACE_GRANULE_IN_BYTES (1 << SGEN_TO_SPACE_GRANULE_BITS)
524 extern char *sgen_space_bitmap;
525 extern size_t sgen_space_bitmap_size;
527 static inline gboolean
528 sgen_nursery_is_to_space (void *object)
530 size_t idx = ((char*)object - sgen_nursery_start) >> SGEN_TO_SPACE_GRANULE_BITS;
531 size_t byte = idx >> 3;
532 size_t bit = idx & 0x7;
534 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 ());
535 SGEN_ASSERT (4, byte < sgen_space_bitmap_size, "byte index %zd out of range (%zd)", byte, sgen_space_bitmap_size);
537 return (sgen_space_bitmap [byte] & (1 << bit)) != 0;
540 static inline gboolean
541 sgen_nursery_is_from_space (void *object)
543 return !sgen_nursery_is_to_space (object);
546 static inline gboolean
547 sgen_nursery_is_object_alive (GCObject *obj)
549 /* FIXME put this asserts under a non default level */
550 g_assert (sgen_ptr_in_nursery (obj));
552 if (sgen_nursery_is_to_space (obj))
555 if (SGEN_OBJECT_IS_PINNED (obj) || SGEN_OBJECT_IS_FORWARDED (obj))
563 gboolean is_parallel;
565 GCObject* (*alloc_for_promotion) (GCVTable vtable, GCObject *obj, size_t objsize, gboolean has_references);
567 SgenObjectOperations serial_ops;
568 SgenObjectOperations serial_ops_with_concurrent_major;
569 SgenObjectOperations parallel_ops;
571 void (*prepare_to_space) (char *to_space_bitmap, size_t space_bitmap_size);
572 void (*clear_fragments) (void);
573 SgenFragment* (*build_fragments_get_exclude_head) (void);
574 void (*build_fragments_release_exclude_head) (void);
575 void (*build_fragments_finish) (SgenFragmentAllocator *allocator);
576 void (*init_nursery) (SgenFragmentAllocator *allocator, char *start, char *end);
578 gboolean (*handle_gc_param) (const char *opt); /* Optional */
579 void (*print_gc_param_usage) (void); /* Optional */
580 } SgenMinorCollector;
582 extern SgenMinorCollector sgen_minor_collector;
584 void sgen_simple_nursery_init (SgenMinorCollector *collector, gboolean parallel);
585 void sgen_split_nursery_init (SgenMinorCollector *collector);
587 /* Updating references */
589 #ifdef SGEN_CHECK_UPDATE_REFERENCE
590 gboolean sgen_thread_pool_is_thread_pool_thread (MonoNativeThreadId some_thread);
593 sgen_update_reference (GCObject **p, GCObject *o, gboolean allow_null)
596 SGEN_ASSERT (0, o, "Cannot update a reference with a NULL pointer");
597 SGEN_ASSERT (0, !sgen_workers_is_worker_thread (mono_native_thread_id_get ()), "Can't update a reference in the worker thread");
601 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o) sgen_update_reference ((GCObject**)(p), (GCObject*)(o), TRUE)
602 #define SGEN_UPDATE_REFERENCE(p,o) sgen_update_reference ((GCObject**)(p), (GCObject*)(o), FALSE)
604 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o) (*(GCObject**)(p) = (GCObject*)(o))
605 #define SGEN_UPDATE_REFERENCE(p,o) SGEN_UPDATE_REFERENCE_ALLOW_NULL ((p), (o))
608 /* Major collector */
610 typedef void (*sgen_cardtable_block_callback) (mword start, mword size);
611 void sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
612 void sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback);
615 ITERATE_OBJECTS_SWEEP = 1,
616 ITERATE_OBJECTS_NON_PINNED = 2,
617 ITERATE_OBJECTS_PINNED = 4,
618 ITERATE_OBJECTS_SWEEP_NON_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED,
619 ITERATE_OBJECTS_SWEEP_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_PINNED,
620 ITERATE_OBJECTS_SWEEP_ALL = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED | ITERATE_OBJECTS_PINNED
621 } IterateObjectsFlags;
625 size_t num_scanned_objects;
626 size_t num_unique_scanned_objects;
627 } ScannedObjectCounts;
630 CARDTABLE_SCAN_GLOBAL = 0,
631 CARDTABLE_SCAN_MOD_UNION = 1,
632 CARDTABLE_SCAN_MOD_UNION_PRECLEAN = CARDTABLE_SCAN_MOD_UNION | 2,
635 typedef struct _SgenMajorCollector SgenMajorCollector;
636 struct _SgenMajorCollector {
638 gboolean is_concurrent;
639 gboolean is_parallel;
640 gboolean supports_cardtable;
641 gboolean sweeps_lazily;
643 void* (*alloc_heap) (mword nursery_size, mword nursery_align, int nursery_bits);
644 gboolean (*is_object_live) (GCObject *obj);
645 GCObject* (*alloc_small_pinned_obj) (GCVTable vtable, size_t size, gboolean has_references);
646 GCObject* (*alloc_degraded) (GCVTable vtable, size_t size);
648 SgenObjectOperations major_ops_serial;
649 SgenObjectOperations major_ops_concurrent_start;
650 SgenObjectOperations major_ops_concurrent_finish;
651 SgenObjectOperations major_ops_conc_par_start;
652 SgenObjectOperations major_ops_conc_par_finish;
654 GCObject* (*alloc_object) (GCVTable vtable, size_t size, gboolean has_references);
655 GCObject* (*alloc_object_par) (GCVTable vtable, size_t size, gboolean has_references);
656 void (*free_pinned_object) (GCObject *obj, size_t size);
659 * This is used for domain unloading, heap walking from the logging profiler, and
660 * debugging. Can assume the world is stopped.
662 void (*iterate_objects) (IterateObjectsFlags flags, IterateObjectCallbackFunc callback, void *data);
664 void (*free_non_pinned_object) (GCObject *obj, size_t size);
665 void (*pin_objects) (SgenGrayQueue *queue);
666 void (*pin_major_object) (GCObject *obj, SgenGrayQueue *queue);
667 void (*scan_card_table) (CardTableScanType scan_type, ScanCopyContext ctx, int job_index, int job_split_count);
668 void (*iterate_live_block_ranges) (sgen_cardtable_block_callback callback);
669 void (*iterate_block_ranges) (sgen_cardtable_block_callback callback);
670 void (*update_cardtable_mod_union) (void);
671 void (*init_to_space) (void);
672 void (*sweep) (void);
673 gboolean (*have_swept) (void);
674 void (*finish_sweeping) (void);
675 void (*free_swept_blocks) (size_t section_reserve);
676 void (*check_scan_starts) (void);
677 void (*dump_heap) (FILE *heap_dump_file);
678 gint64 (*get_used_size) (void);
679 void (*start_nursery_collection) (void);
680 void (*finish_nursery_collection) (void);
681 void (*start_major_collection) (void);
682 void (*finish_major_collection) (ScannedObjectCounts *counts);
683 gboolean (*ptr_is_in_non_pinned_space) (char *ptr, char **start);
684 gboolean (*ptr_is_from_pinned_alloc) (char *ptr);
685 void (*report_pinned_memory_usage) (void);
686 size_t (*get_num_major_sections) (void);
687 size_t (*get_bytes_survived_last_sweep) (void);
688 gboolean (*handle_gc_param) (const char *opt);
689 void (*print_gc_param_usage) (void);
690 void (*post_param_init) (SgenMajorCollector *collector);
691 gboolean (*is_valid_object) (char *ptr);
692 GCVTable (*describe_pointer) (char *pointer);
693 guint8* (*get_cardtable_mod_union_for_reference) (char *object);
694 long long (*get_and_reset_num_major_objects_marked) (void);
695 void (*count_cards) (long long *num_total_cards, long long *num_marked_cards);
696 SgenThreadPool* (*get_sweep_pool) (void);
698 void (*worker_init_cb) (gpointer worker);
701 extern SgenMajorCollector major_collector;
703 void sgen_marksweep_init (SgenMajorCollector *collector);
704 void sgen_marksweep_conc_init (SgenMajorCollector *collector);
705 void sgen_marksweep_conc_par_init (SgenMajorCollector *collector);
706 SgenMajorCollector* sgen_get_major_collector (void);
707 SgenMinorCollector* sgen_get_minor_collector (void);
710 typedef struct _SgenRememberedSet {
711 void (*wbarrier_set_field) (GCObject *obj, gpointer field_ptr, GCObject* value);
712 void (*wbarrier_arrayref_copy) (gpointer dest_ptr, gpointer src_ptr, int count);
713 void (*wbarrier_value_copy) (gpointer dest, gpointer src, int count, size_t element_size);
714 void (*wbarrier_object_copy) (GCObject* obj, GCObject *src);
715 void (*wbarrier_generic_nostore) (gpointer ptr);
716 void (*record_pointer) (gpointer ptr);
718 void (*start_scan_remsets) (void);
720 void (*clear_cards) (void);
722 gboolean (*find_address) (char *addr);
723 gboolean (*find_address_with_cards) (char *cards_start, guint8 *cards, char *addr);
726 SgenRememberedSet *sgen_get_remset (void);
729 * These must be kept in sync with object.h. They're here for using SGen independently of
732 void mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count);
733 void mono_gc_wbarrier_generic_nostore (gpointer ptr);
734 void mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value);
735 void mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value);
737 void sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap);
739 static inline SgenDescriptor
740 sgen_obj_get_descriptor (GCObject *obj)
742 GCVTable vtable = SGEN_LOAD_VTABLE_UNCHECKED (obj);
743 SGEN_ASSERT (9, !SGEN_POINTER_IS_TAGGED_ANY (vtable), "Object can't be tagged");
744 return sgen_vtable_get_descriptor (vtable);
747 static inline SgenDescriptor
748 sgen_obj_get_descriptor_safe (GCObject *obj)
750 GCVTable vtable = SGEN_LOAD_VTABLE (obj);
751 return sgen_vtable_get_descriptor (vtable);
754 static mword sgen_client_par_object_get_size (GCVTable vtable, GCObject* o);
755 static mword sgen_client_slow_object_get_size (GCVTable vtable, GCObject* o);
758 sgen_safe_object_get_size (GCObject *obj)
761 GCVTable vtable = SGEN_LOAD_VTABLE_UNCHECKED (obj);
764 * Once we load the vtable, we must always use it, in case we are in parallel case.
765 * Otherwise the object might get forwarded in the meantime and we would read an
766 * invalid vtable. An object cannot be forwarded for a second time during same GC.
768 if ((forwarded = SGEN_VTABLE_IS_FORWARDED (vtable)))
769 return sgen_client_par_object_get_size (SGEN_LOAD_VTABLE (forwarded), obj);
771 return sgen_client_par_object_get_size ((GCVTable)SGEN_POINTER_UNTAG_ALL (vtable), obj);
774 static inline gboolean
775 sgen_safe_object_is_small (GCObject *obj, int type)
777 if (type <= DESC_TYPE_MAX_SMALL_OBJ)
779 return SGEN_ALIGN_UP (sgen_safe_object_get_size ((GCObject*)obj)) <= SGEN_MAX_SMALL_OBJ_SIZE;
783 * This variant guarantees to return the exact size of the object
784 * before alignment. Needed for canary support.
787 sgen_safe_object_get_size_unaligned (GCObject *obj)
791 if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
792 obj = (GCObject*)forwarded;
795 return sgen_client_slow_object_get_size (SGEN_LOAD_VTABLE (obj), obj);
798 #ifdef SGEN_CLIENT_HEADER
799 #include SGEN_CLIENT_HEADER
801 #include "metadata/sgen-client-mono.h"
804 gboolean sgen_object_is_live (GCObject *obj);
806 void sgen_init_fin_weak_hash (void);
808 /* FIXME: move the toggleref stuff out of here */
809 void sgen_mark_togglerefs (char *start, char *end, ScanCopyContext ctx);
810 void sgen_clear_togglerefs (char *start, char *end, ScanCopyContext ctx);
812 void sgen_process_togglerefs (void);
813 void sgen_register_test_toggleref_callback (void);
815 void sgen_mark_bridge_object (GCObject *obj);
816 void sgen_collect_bridge_objects (int generation, ScanCopyContext ctx);
818 typedef gboolean (*SgenObjectPredicateFunc) (GCObject *obj, void *user_data);
820 void sgen_null_links_if (SgenObjectPredicateFunc predicate, void *data, int generation, gboolean track);
822 gboolean sgen_gc_is_object_ready_for_finalization (GCObject *object);
823 void sgen_gc_lock (void);
824 void sgen_gc_unlock (void);
826 void sgen_queue_finalization_entry (GCObject *obj);
827 const char* sgen_generation_name (int generation);
829 void sgen_finalize_in_range (int generation, ScanCopyContext ctx);
830 void sgen_null_link_in_range (int generation, ScanCopyContext ctx, gboolean track);
831 void sgen_process_fin_stage_entries (void);
832 gboolean sgen_have_pending_finalizers (void);
833 void sgen_object_register_for_finalization (GCObject *obj, void *user_data);
835 void sgen_finalize_if (SgenObjectPredicateFunc predicate, void *user_data);
836 void sgen_remove_finalizers_if (SgenObjectPredicateFunc predicate, void *user_data, int generation);
837 void sgen_set_suspend_finalizers (void);
839 void sgen_wbroots_iterate_live_block_ranges (sgen_cardtable_block_callback cb);
840 void sgen_wbroots_scan_card_table (ScanCopyContext ctx);
842 void sgen_register_disappearing_link (GCObject *obj, void **link, gboolean track, gboolean in_gc);
844 GCObject* sgen_weak_link_get (void **link_addr);
846 gboolean sgen_drain_gray_stack (ScanCopyContext ctx);
854 void sgen_pin_object (GCObject *object, SgenGrayQueue *queue);
855 void sgen_set_pinned_from_failed_allocation (mword objsize);
857 void sgen_ensure_free_space (size_t size, int generation);
858 void sgen_gc_collect (int generation);
859 void sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw);
861 int sgen_gc_collection_count (int generation);
862 /* FIXME: what exactly does this return? */
863 size_t sgen_gc_get_used_size (void);
864 size_t sgen_gc_get_total_heap_allocation (void);
868 void sgen_stop_world (int generation);
869 void sgen_restart_world (int generation);
870 gboolean sgen_is_world_stopped (void);
872 gboolean sgen_set_allow_synchronous_major (gboolean flag);
876 typedef struct _LOSObject LOSObject;
879 mword size; /* this is the object size, lowest bit used for pin/mark */
880 guint8 * volatile cardtable_mod_union; /* only used by the concurrent collector */
881 #if SIZEOF_VOID_P < 8
882 mword dummy; /* to align object to sizeof (double) */
884 GCObject data [MONO_ZERO_LEN_ARRAY];
887 extern LOSObject *los_object_list;
888 extern mword los_memory_usage;
889 extern mword los_memory_usage_total;
891 void sgen_los_free_object (LOSObject *obj);
892 void* sgen_los_alloc_large_inner (GCVTable vtable, size_t size);
893 void sgen_los_sweep (void);
894 gboolean sgen_ptr_is_in_los (char *ptr, char **start);
895 void sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data);
896 void sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
897 void sgen_los_scan_card_table (CardTableScanType scan_type, ScanCopyContext ctx, int job_index, int job_split_count);
898 void sgen_los_update_cardtable_mod_union (void);
899 void sgen_los_count_cards (long long *num_total_cards, long long *num_marked_cards);
900 gboolean sgen_los_is_valid_object (char *object);
901 gboolean mono_sgen_los_describe_pointer (char *ptr);
902 LOSObject* sgen_los_header_for_object (GCObject *data);
903 mword sgen_los_object_size (LOSObject *obj);
904 void sgen_los_pin_object (GCObject *obj);
905 gboolean sgen_los_pin_object_par (GCObject *obj);
906 gboolean sgen_los_object_is_pinned (GCObject *obj);
907 void sgen_los_mark_mod_union_card (GCObject *mono_obj, void **ptr);
910 /* nursery allocator */
912 void sgen_clear_nursery_fragments (void);
913 void sgen_nursery_allocator_prepare_for_pinning (void);
914 void sgen_nursery_allocator_set_nursery_bounds (char *nursery_start, char *nursery_end);
915 mword sgen_build_nursery_fragments (GCMemSection *nursery_section, SgenGrayQueue *unpin_queue);
916 void sgen_init_nursery_allocator (void);
917 void sgen_nursery_allocator_init_heavy_stats (void);
918 void sgen_init_allocator (void);
919 char* sgen_nursery_alloc_get_upper_alloc_bound (void);
920 void* sgen_nursery_alloc (size_t size);
921 void* sgen_nursery_alloc_range (size_t size, size_t min_size, size_t *out_alloc_size);
922 gboolean sgen_can_alloc_size (size_t size);
923 void sgen_nursery_retire_region (void *address, ptrdiff_t size);
925 void sgen_nursery_alloc_prepare_for_minor (void);
926 void sgen_nursery_alloc_prepare_for_major (void);
928 GCObject* sgen_alloc_for_promotion (GCObject *obj, size_t objsize, gboolean has_references);
930 GCObject* sgen_alloc_obj_nolock (GCVTable vtable, size_t size);
931 GCObject* sgen_try_alloc_obj_nolock (GCVTable vtable, size_t size);
935 void* sgen_thread_register (SgenThreadInfo* info, void *addr);
936 void sgen_thread_unregister (SgenThreadInfo *p);
938 /* Finalization/ephemeron support */
940 static inline gboolean
941 sgen_major_is_object_alive (GCObject *object)
945 /* Oldgen objects can be pinned and forwarded too */
946 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
950 * FIXME: major_collector.is_object_live() also calculates the
951 * size. Avoid the double calculation.
953 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size (object));
954 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
955 return sgen_los_object_is_pinned (object);
957 return major_collector.is_object_live (object);
961 * This function returns true if @object is either alive or it belongs to the old gen
962 * and we're currently doing a minor collection.
965 sgen_is_object_alive_for_current_gen (GCObject *object)
967 if (sgen_ptr_in_nursery (object))
968 return sgen_nursery_is_object_alive (object);
970 if (current_collection_generation == GENERATION_NURSERY)
973 return sgen_major_is_object_alive (object);
976 int sgen_gc_invoke_finalizers (void);
980 void sgen_init_gchandles (void);
982 void sgen_null_links_if (SgenObjectPredicateFunc predicate, void *data, int generation, gboolean track);
984 typedef gpointer (*SgenGCHandleIterateCallback) (gpointer hidden, GCHandleType handle_type, int max_generation, gpointer user);
986 void sgen_gchandle_iterate (GCHandleType handle_type, int max_generation, SgenGCHandleIterateCallback callback, gpointer user);
987 void sgen_gchandle_set_target (guint32 gchandle, GCObject *obj);
988 void sgen_mark_normal_gc_handles (void *addr, SgenUserMarkFunc mark_func, void *gc_data);
989 gpointer sgen_gchandle_get_metadata (guint32 gchandle);
993 extern GCMemSection *nursery_section;
994 extern guint32 collect_before_allocs;
995 extern guint32 verify_before_allocs;
996 extern gboolean has_per_allocation_action;
997 extern size_t degraded_mode;
998 extern int default_nursery_size;
999 extern guint32 tlab_size;
1000 extern NurseryClearPolicy nursery_clear_policy;
1001 extern gboolean sgen_try_free_some_memory;
1002 extern mword total_promoted_size;
1003 extern mword total_allocated_major;
1004 extern volatile gboolean sgen_suspend_finalizers;
1005 extern MonoCoopMutex gc_mutex;
1007 /* Nursery helpers. */
1010 sgen_set_nursery_scan_start (char *p)
1012 size_t idx = (p - (char*)nursery_section->data) / SGEN_SCAN_START_SIZE;
1013 char *old = nursery_section->scan_starts [idx];
1014 if (!old || old > p)
1015 nursery_section->scan_starts [idx] = p;
1019 /* Object Allocation */
1027 } SgenAllocatorType;
1029 void sgen_clear_tlabs (void);
1031 GCObject* sgen_alloc_obj (GCVTable vtable, size_t size);
1032 GCObject* sgen_alloc_obj_pinned (GCVTable vtable, size_t size);
1033 GCObject* sgen_alloc_obj_mature (GCVTable vtable, size_t size);
1037 void sgen_check_remset_consistency (void);
1038 void sgen_check_mod_union_consistency (void);
1039 void sgen_check_major_refs (void);
1040 void sgen_check_whole_heap (gboolean allow_missing_pinning);
1041 void sgen_check_whole_heap_stw (void);
1042 void sgen_check_objref (char *obj);
1043 void sgen_check_heap_marked (gboolean nursery_must_be_pinned);
1044 void sgen_check_nursery_objects_pinned (gboolean pinned);
1045 void sgen_check_for_xdomain_refs (void);
1046 GCObject* sgen_find_object_for_ptr (char *ptr);
1048 void mono_gc_scan_for_specific_ref (GCObject *key, gboolean precise);
1050 void sgen_debug_enable_heap_dump (const char *filename);
1051 void sgen_debug_dump_heap (const char *type, int num, const char *reason);
1053 void sgen_debug_verify_nursery (gboolean do_dump_nursery_content);
1054 void sgen_debug_check_nursery_is_clean (void);
1056 /* Environment variable parsing */
1058 #define MONO_GC_PARAMS_NAME "MONO_GC_PARAMS"
1059 #define MONO_GC_DEBUG_NAME "MONO_GC_DEBUG"
1061 void sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...);
1065 void sgen_qsort (void *array, size_t count, size_t element_size, int (*compare) (const void*, const void*));
1066 gint64 sgen_timestamp (void);
1069 * Canary (guard word) support
1071 * - CANARY_SIZE must be multiple of word size in bytes
1072 * - Canary space is not included on checks against SGEN_MAX_SMALL_OBJ_SIZE
1075 gboolean nursery_canaries_enabled (void);
1077 #define CANARY_SIZE 8
1078 #define CANARY_STRING "koupepia"
1080 #define CANARIFY_SIZE(size) if (nursery_canaries_enabled ()) { \
1081 size = size + CANARY_SIZE; \
1084 #define CANARIFY_ALLOC(addr,size) if (nursery_canaries_enabled ()) { \
1085 memcpy ((char*) (addr) + (size), CANARY_STRING, CANARY_SIZE); \
1088 #define CANARY_VALID(addr) (strncmp ((char*) (addr), CANARY_STRING, CANARY_SIZE) == 0)
1090 #define CHECK_CANARY_FOR_OBJECT(addr,fail) if (nursery_canaries_enabled ()) { \
1091 guint size = sgen_safe_object_get_size_unaligned ((GCObject *) (addr)); \
1092 char* canary_ptr = (char*) (addr) + size; \
1093 if (!CANARY_VALID(canary_ptr)) { \
1094 char *window_start, *window_end; \
1095 window_start = (char*)(addr) - 128; \
1096 if (!sgen_ptr_in_nursery (window_start)) \
1097 window_start = sgen_get_nursery_start (); \
1098 window_end = (char*)(addr) + 128; \
1099 if (!sgen_ptr_in_nursery (window_end)) \
1100 window_end = sgen_get_nursery_end (); \
1101 fprintf (stderr, "\nCANARY ERROR - Type:%s Size:%d Address:%p Data:\n", sgen_client_vtable_get_name (SGEN_LOAD_VTABLE ((addr))), size, (char*) addr); \
1102 fwrite (addr, sizeof (char), size, stderr); \
1103 fprintf (stderr, "\nCanary zone (next 12 chars):\n"); \
1104 fwrite (canary_ptr, sizeof (char), 12, stderr); \
1105 fprintf (stderr, "\nOriginal canary string:\n"); \
1106 fwrite (CANARY_STRING, sizeof (char), 8, stderr); \
1107 for (int x = -8; x <= 8; x++) { \
1108 if (canary_ptr + x < (char*) addr); \
1110 if (CANARY_VALID(canary_ptr +x)) \
1111 fprintf (stderr, "\nCANARY ERROR - canary found at offset %d\n", x); \
1113 fprintf (stderr, "\nSurrounding nursery (%p - %p):\n", window_start, window_end); \
1114 fwrite (window_start, sizeof (char), window_end - window_start, stderr); \
1118 * This causes the compile to extend the liveness of 'v' till the call to dummy_use
1121 sgen_dummy_use (gpointer v)
1123 #if defined(__GNUC__)
1124 __asm__ volatile ("" : "=r"(v) : "r"(v));
1125 #elif defined(_MSC_VER)
1126 static volatile gpointer ptr;
1129 #error "Implement sgen_dummy_use for your compiler"
1133 #endif /* HAVE_SGEN_GC */
1135 #endif /* __MONO_SGENGC_H__ */