2 * sgen-gc.c: Simple generational GC.
4 * Copyright 2001-2003 Ximian, Inc
5 * Copyright 2003-2010 Novell, Inc.
6 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
7 * Copyright (C) 2012 Xamarin Inc
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Library General Public
11 * License 2.0 as published by the Free Software Foundation;
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License 2.0 along with this library; if not, write to the Free
20 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 #ifndef __MONO_SGENGC_H__
23 #define __MONO_SGENGC_H__
30 typedef struct _SgenThreadInfo SgenThreadInfo;
31 #undef THREAD_INFO_TYPE
32 #define THREAD_INFO_TYPE SgenThreadInfo
38 #include <mono/utils/mono-compiler.h>
39 #include <mono/utils/atomic.h>
40 #include <mono/utils/mono-mutex.h>
41 #include <mono/metadata/sgen-conf.h>
42 #include <mono/metadata/sgen-archdep.h>
43 #include <mono/metadata/sgen-descriptor.h>
44 #include <mono/metadata/sgen-gray.h>
45 #include <mono/metadata/sgen-hash-table.h>
46 #include <mono/metadata/sgen-bridge.h>
47 #include <mono/metadata/sgen-protocol.h>
49 /* The method used to clear the nursery */
50 /* Clearing at nursery collections is the safest, but has bad interactions with caches.
51 * Clearing at TLAB creation is much faster, but more complex and it might expose hard
56 CLEAR_AT_TLAB_CREATION,
57 CLEAR_AT_TLAB_CREATION_DEBUG
60 NurseryClearPolicy sgen_get_nursery_clear_policy (void);
62 #define SGEN_TV_DECLARE(name) gint64 name
63 #define SGEN_TV_GETTIME(tv) tv = mono_100ns_ticks ()
64 #define SGEN_TV_ELAPSED(start,end) (int)((end-start))
66 #if !defined(__MACH__) && !MONO_MACH_ARCH_SUPPORTED && defined(HAVE_PTHREAD_KILL)
67 #define SGEN_POSIX_STW 1
71 * The nursery section uses this struct.
73 typedef struct _GCMemSection GCMemSection;
74 struct _GCMemSection {
77 /* pointer where more data could be allocated if it fits */
81 * scan starts is an array of pointers to objects equally spaced in the allocation area
82 * They let use quickly find pinned objects from pinning pointers.
85 /* in major collections indexes in the pin_queue for objects that pin this section */
86 size_t pin_queue_first_entry;
87 size_t pin_queue_last_entry;
88 size_t num_scan_start;
92 * Recursion is not allowed for the thread lock.
94 #define LOCK_DECLARE(name) mono_mutex_t name
95 /* if changing LOCK_INIT to something that isn't idempotent, look at
96 its use in mono_gc_base_init in sgen-gc.c */
97 #define LOCK_INIT(name) mono_mutex_init (&(name))
98 #define LOCK_GC do { \
100 mono_mutex_lock (&gc_mutex); \
101 MONO_FINISH_TRY_BLOCKING \
103 #define UNLOCK_GC do { sgen_gc_unlock (); } while (0)
105 extern LOCK_DECLARE (sgen_interruption_mutex);
107 #define LOCK_INTERRUPTION mono_mutex_lock (&sgen_interruption_mutex)
108 #define UNLOCK_INTERRUPTION mono_mutex_unlock (&sgen_interruption_mutex)
110 /* FIXME: Use InterlockedAdd & InterlockedAdd64 to reduce the CAS cost. */
111 #define SGEN_CAS InterlockedCompareExchange
112 #define SGEN_CAS_PTR InterlockedCompareExchangePointer
113 #define SGEN_ATOMIC_ADD(x,i) do { \
117 } while (InterlockedCompareExchange (&(x), __old_x + (i), __old_x) != __old_x); \
119 #define SGEN_ATOMIC_ADD_P(x,i) do { \
123 } while (InterlockedCompareExchangePointer ((void**)&(x), (void*)(__old_x + (i)), (void*)__old_x) != (void*)__old_x); \
128 /* we intercept pthread_create calls to know which threads exist */
129 #define USE_PTHREAD_INTERCEPT 1
132 #ifdef HEAVY_STATISTICS
133 extern guint64 stat_objects_alloced_degraded;
134 extern guint64 stat_bytes_alloced_degraded;
135 extern guint64 stat_copy_object_called_major;
136 extern guint64 stat_objects_copied_major;
139 #define SGEN_ASSERT(level, a, ...) do { \
140 if (G_UNLIKELY ((level) <= SGEN_MAX_ASSERT_LEVEL && !(a))) { \
141 g_error (__VA_ARGS__); \
145 #define SGEN_LOG(level, format, ...) do { \
146 if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) { \
147 mono_gc_printf (gc_debug_file, format, ##__VA_ARGS__); \
150 #define SGEN_COND_LOG(level, cond, format, ...) do { \
151 if (G_UNLIKELY ((level) <= SGEN_MAX_DEBUG_LEVEL && (level) <= gc_debug_level)) { \
153 mono_gc_printf (gc_debug_file, format, ##__VA_ARGS__); \
156 extern int gc_debug_level;
157 extern FILE* gc_debug_file;
159 extern int current_collection_generation;
161 extern unsigned int sgen_global_stop_count;
163 extern gboolean bridge_processing_in_progress;
164 extern MonoGCBridgeCallbacks bridge_callbacks;
166 #define SGEN_ALLOC_ALIGN 8
167 #define SGEN_ALLOC_ALIGN_BITS 3
169 /* s must be non-negative */
170 #define SGEN_CAN_ALIGN_UP(s) ((s) <= SIZE_MAX - (SGEN_ALLOC_ALIGN - 1))
171 #define SGEN_ALIGN_UP(s) (((s)+(SGEN_ALLOC_ALIGN-1)) & ~(SGEN_ALLOC_ALIGN-1))
173 #if SIZEOF_VOID_P == 4
180 * The link pointer is hidden by negating each bit. We use the lowest
181 * bit of the link (before negation) to store whether it needs
182 * resurrection tracking.
184 #define HIDE_POINTER(p,t) ((gpointer)(~((size_t)(p)|((t)?1:0))))
185 #define REVEAL_POINTER(p) ((gpointer)((~(size_t)(p))&~3L))
187 #define SGEN_PTR_IN_NURSERY(p,bits,start,end) (((mword)(p) & ~((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) (SGEN_POINTER_IS_TAGGED_FORWARDED ((vtable)) ? SGEN_POINTER_UNTAG_VTABLE ((vtable)) : NULL)
260 #define SGEN_OBJECT_IS_FORWARDED(obj) (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_PIN_OBJECT(obj) do { \
272 *(void**)(obj) = SGEN_POINTER_TAG_PINNED (*(void**)(obj)); \
274 #define SGEN_CEMENT_OBJECT(obj) do { \
275 *(void**)(obj) = SGEN_POINTER_TAG_CEMENTED (*(void**)(obj)); \
277 /* Unpins and uncements */
278 #define SGEN_UNPIN_OBJECT(obj) do { \
279 *(void**)(obj) = SGEN_POINTER_UNTAG_VTABLE (*(void**)(obj)); \
283 * Since we set bits in the vtable, use the macro to load it from the pointer to
284 * an object that is potentially pinned.
286 #define SGEN_LOAD_VTABLE(obj) SGEN_POINTER_UNTAG_ALL (SGEN_LOAD_VTABLE_UNCHECKED ((obj)))
289 List of what each bit on of the vtable gc bits means.
292 SGEN_GC_BIT_BRIDGE_OBJECT = 1,
293 SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT = 2,
294 SGEN_GC_BIT_FINALIZER_AWARE = 4,
297 /* the runtime can register areas of memory as roots: we keep two lists of roots,
298 * a pinned root set for conservatively scanned roots and a normal one for
299 * precisely scanned roots (currently implemented as a single list).
301 typedef struct _RootRecord RootRecord;
308 ROOT_TYPE_NORMAL = 0, /* "normal" roots */
309 ROOT_TYPE_PINNED = 1, /* roots without a GC descriptor */
310 ROOT_TYPE_WBARRIER = 2, /* roots with a write barrier */
314 extern SgenHashTable roots_hash [ROOT_TYPE_NUM];
316 typedef void (*IterateObjectCallbackFunc) (char*, size_t, void*);
318 void sgen_os_init (void);
320 void sgen_update_heap_boundaries (mword low, mword high);
322 void sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags);
323 void sgen_check_section_scan_starts (GCMemSection *section);
325 void sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type);
327 /* Keep in sync with description_for_type() in sgen-internal.c! */
329 INTERNAL_MEM_PIN_QUEUE,
330 INTERNAL_MEM_FRAGMENT,
331 INTERNAL_MEM_SECTION,
332 INTERNAL_MEM_SCAN_STARTS,
333 INTERNAL_MEM_FIN_TABLE,
334 INTERNAL_MEM_FINALIZE_ENTRY,
335 INTERNAL_MEM_FINALIZE_READY,
336 INTERNAL_MEM_DISLINK_TABLE,
337 INTERNAL_MEM_DISLINK,
338 INTERNAL_MEM_ROOTS_TABLE,
339 INTERNAL_MEM_ROOT_RECORD,
340 INTERNAL_MEM_STATISTICS,
341 INTERNAL_MEM_STAT_PINNED_CLASS,
342 INTERNAL_MEM_STAT_REMSET_CLASS,
343 INTERNAL_MEM_GRAY_QUEUE,
344 INTERNAL_MEM_MS_TABLES,
345 INTERNAL_MEM_MS_BLOCK_INFO,
346 INTERNAL_MEM_MS_BLOCK_INFO_SORT,
347 INTERNAL_MEM_WORKER_DATA,
348 INTERNAL_MEM_THREAD_POOL_JOB,
349 INTERNAL_MEM_BRIDGE_DATA,
350 INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE,
351 INTERNAL_MEM_OLD_BRIDGE_HASH_TABLE_ENTRY,
352 INTERNAL_MEM_BRIDGE_HASH_TABLE,
353 INTERNAL_MEM_BRIDGE_HASH_TABLE_ENTRY,
354 INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE,
355 INTERNAL_MEM_BRIDGE_ALIVE_HASH_TABLE_ENTRY,
356 INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE,
357 INTERNAL_MEM_TARJAN_BRIDGE_HASH_TABLE_ENTRY,
358 INTERNAL_MEM_TARJAN_OBJ_BUCKET,
359 INTERNAL_MEM_BRIDGE_DEBUG,
360 INTERNAL_MEM_TOGGLEREF_DATA,
361 INTERNAL_MEM_CARDTABLE_MOD_UNION,
362 INTERNAL_MEM_BINARY_PROTOCOL,
363 INTERNAL_MEM_TEMPORARY,
364 INTERNAL_MEM_FIRST_CLIENT
373 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
374 #define BINARY_PROTOCOL_ARG(x) ,x
376 #define BINARY_PROTOCOL_ARG(x)
379 void sgen_init_internal_allocator (void);
381 #define SGEN_DEFINE_OBJECT_VTABLE
382 #include "sgen-client-mono.h"
383 #undef SGEN_DEFINE_OBJECT_VTABLE
385 /* eventually share with MonoThread? */
387 * This structure extends the MonoThreadInfo structure.
389 struct _SgenThreadInfo {
390 SgenClientThreadInfo client_info;
393 This is set to TRUE when STW fails to suspend a thread, most probably because the
394 underlying thread is dead.
396 gboolean skip, suspend_done;
397 volatile int in_critical_region;
400 This is set the argument of mono_gc_set_skip_thread.
402 A thread that knowingly holds no managed state can call this
403 function around blocking loops to reduce the GC burden by not
406 gboolean gc_disabled;
409 void *stack_start_limit;
410 char **tlab_next_addr;
411 char **tlab_start_addr;
412 char **tlab_temp_end_addr;
413 char **tlab_real_end_addr;
414 gpointer runtime_data;
416 #ifdef SGEN_POSIX_STW
417 /* This is -1 until the first suspend. */
419 /* FIXME: kill this, we only use signals on systems that have rt-posix, which doesn't have issues with duplicates. */
420 unsigned int stop_count; /* to catch duplicate signals. */
423 /*FIXME pretty please finish killing ARCH_NUM_REGS */
425 MonoContext ctx; /* ditto */
427 gpointer regs[ARCH_NUM_REGS]; /* ditto */
430 #ifndef HAVE_KW_THREAD
438 gboolean sgen_is_worker_thread (MonoNativeThreadId thread);
440 typedef void (*CopyOrMarkObjectFunc) (void**, SgenGrayQueue*);
441 typedef void (*ScanObjectFunc) (char *obj, mword desc, SgenGrayQueue*);
442 typedef void (*ScanVTypeFunc) (char *full_object, char *start, mword desc, SgenGrayQueue* BINARY_PROTOCOL_ARG (size_t size));
445 CopyOrMarkObjectFunc copy_or_mark_object;
446 ScanObjectFunc scan_object;
447 ScanVTypeFunc scan_vtype;
448 /*FIXME add allocation function? */
449 } SgenObjectOperations;
453 SgenObjectOperations *ops;
454 SgenGrayQueue *queue;
457 #define CONTEXT_FROM_OBJECT_OPERATIONS(ops, queue) ((ScanCopyContext) { (ops), (queue) })
459 void sgen_report_internal_mem_usage (void);
460 void sgen_dump_internal_mem_usage (FILE *heap_dump_file);
461 void sgen_dump_section (GCMemSection *section, const char *type);
462 void sgen_dump_occupied (char *start, char *end, char *section_start);
464 void sgen_register_fixed_internal_mem_type (int type, size_t size);
466 void* sgen_alloc_internal (int type);
467 void sgen_free_internal (void *addr, int type);
469 void* sgen_alloc_internal_dynamic (size_t size, int type, gboolean assert_on_failure);
470 void sgen_free_internal_dynamic (void *addr, size_t size, int type);
472 void sgen_pin_stats_enable (void);
473 void sgen_pin_stats_register_object (char *obj, size_t size);
474 void sgen_pin_stats_register_global_remset (char *obj);
475 void sgen_pin_stats_print_class_stats (void);
477 void sgen_sort_addresses (void **array, size_t size);
478 void sgen_add_to_global_remset (gpointer ptr, gpointer obj);
480 int sgen_get_current_collection_generation (void);
481 gboolean sgen_collection_is_concurrent (void);
482 gboolean sgen_concurrent_collection_in_progress (void);
484 typedef struct _SgenFragment SgenFragment;
486 struct _SgenFragment {
488 char *fragment_start;
489 char *fragment_next; /* the current soft limit for allocation */
491 SgenFragment *next_in_order; /* We use a different entry for all active fragments so we can avoid SMR. */
495 SgenFragment *alloc_head; /* List head to be used when allocating memory. Walk with fragment_next. */
496 SgenFragment *region_head; /* List head of the region used by this allocator. Walk with next_in_order. */
497 } SgenFragmentAllocator;
499 void sgen_fragment_allocator_add (SgenFragmentAllocator *allocator, char *start, char *end);
500 void sgen_fragment_allocator_release (SgenFragmentAllocator *allocator);
501 void* sgen_fragment_allocator_serial_alloc (SgenFragmentAllocator *allocator, size_t size);
502 void* sgen_fragment_allocator_par_alloc (SgenFragmentAllocator *allocator, size_t size);
503 void* sgen_fragment_allocator_serial_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
504 void* sgen_fragment_allocator_par_range_alloc (SgenFragmentAllocator *allocator, size_t desired_size, size_t minimum_size, size_t *out_alloc_size);
505 SgenFragment* sgen_fragment_allocator_alloc (void);
506 void sgen_clear_allocator_fragments (SgenFragmentAllocator *allocator);
507 void sgen_clear_range (char *start, char *end);
511 This is a space/speed compromise as we need to make sure the from/to space check is both O(1)
512 and only hit cache hot memory. On a 4Mb nursery it requires 1024 bytes, or 3% of your average
513 L1 cache. On small configs with a 512kb nursery, this goes to 0.4%.
515 Experimental results on how much space we waste with a 4Mb nursery:
517 Note that the wastage applies to the half nursery, or 2Mb:
519 Test 1 (compiling corlib):
524 #define SGEN_TO_SPACE_GRANULE_BITS 9
525 #define SGEN_TO_SPACE_GRANULE_IN_BYTES (1 << SGEN_TO_SPACE_GRANULE_BITS)
527 extern char *sgen_space_bitmap;
528 extern size_t sgen_space_bitmap_size;
530 static inline gboolean
531 sgen_nursery_is_to_space (char *object)
533 size_t idx = (object - sgen_nursery_start) >> SGEN_TO_SPACE_GRANULE_BITS;
534 size_t byte = idx >> 3;
535 size_t bit = idx & 0x7;
537 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 ());
538 SGEN_ASSERT (4, byte < sgen_space_bitmap_size, "byte index %d out of range", byte, sgen_space_bitmap_size);
540 return (sgen_space_bitmap [byte] & (1 << bit)) != 0;
543 static inline gboolean
544 sgen_nursery_is_from_space (char *object)
546 return !sgen_nursery_is_to_space (object);
549 static inline gboolean
550 sgen_nursery_is_object_alive (char *obj)
552 /* FIXME put this asserts under a non default level */
553 g_assert (sgen_ptr_in_nursery (obj));
555 if (sgen_nursery_is_to_space (obj))
558 if (SGEN_OBJECT_IS_PINNED (obj) || SGEN_OBJECT_IS_FORWARDED (obj))
567 char* (*alloc_for_promotion) (GCVTable *vtable, char *obj, size_t objsize, gboolean has_references);
569 SgenObjectOperations serial_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);
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) MONO_INTERNAL;
592 sgen_update_reference (void **p, void *o, gboolean allow_null)
595 SGEN_ASSERT (0, o, "Cannot update a reference with a NULL pointer");
596 SGEN_ASSERT (0, !sgen_thread_pool_is_thread_pool_thread (mono_native_thread_id_get ()), "Can't update a reference in the worker thread");
600 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o) sgen_update_reference ((void**)(p), (void*)(o), TRUE)
601 #define SGEN_UPDATE_REFERENCE(p,o) sgen_update_reference ((void**)(p), (void*)(o), FALSE)
603 #define SGEN_UPDATE_REFERENCE_ALLOW_NULL(p,o) (*(void**)(p) = (void*)(o))
604 #define SGEN_UPDATE_REFERENCE(p,o) SGEN_UPDATE_REFERENCE_ALLOW_NULL ((p), (o))
607 /* Major collector */
609 typedef void (*sgen_cardtable_block_callback) (mword start, mword size);
610 void sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
613 ITERATE_OBJECTS_SWEEP = 1,
614 ITERATE_OBJECTS_NON_PINNED = 2,
615 ITERATE_OBJECTS_PINNED = 4,
616 ITERATE_OBJECTS_ALL = ITERATE_OBJECTS_NON_PINNED | ITERATE_OBJECTS_PINNED,
617 ITERATE_OBJECTS_SWEEP_NON_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED,
618 ITERATE_OBJECTS_SWEEP_PINNED = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_PINNED,
619 ITERATE_OBJECTS_SWEEP_ALL = ITERATE_OBJECTS_SWEEP | ITERATE_OBJECTS_NON_PINNED | ITERATE_OBJECTS_PINNED
620 } IterateObjectsFlags;
624 size_t num_scanned_objects;
625 size_t num_unique_scanned_objects;
626 } ScannedObjectCounts;
628 typedef struct _SgenMajorCollector SgenMajorCollector;
629 struct _SgenMajorCollector {
631 gboolean is_concurrent;
632 gboolean needs_thread_pool;
633 gboolean supports_cardtable;
634 gboolean sweeps_lazily;
637 * This is set to TRUE by the sweep if the next major
638 * collection should be synchronous (for evacuation). For
639 * non-concurrent collectors, this should be NULL.
641 gboolean *want_synchronous_collection;
643 void* (*alloc_heap) (mword nursery_size, mword nursery_align, int nursery_bits);
644 gboolean (*is_object_live) (char *obj);
645 void* (*alloc_small_pinned_obj) (GCVTable *vtable, size_t size, gboolean has_references);
646 void* (*alloc_degraded) (GCVTable *vtable, size_t size);
648 SgenObjectOperations major_ops_serial;
649 SgenObjectOperations major_ops_concurrent_start;
650 SgenObjectOperations major_ops_concurrent;
651 SgenObjectOperations major_ops_concurrent_finish;
653 void* (*alloc_object) (GCVTable *vtable, size_t size, gboolean has_references);
654 void (*free_pinned_object) (char *obj, size_t size);
657 * This is used for domain unloading, heap walking from the logging profiler, and
658 * debugging. Can assume the world is stopped.
660 void (*iterate_objects) (IterateObjectsFlags flags, IterateObjectCallbackFunc callback, void *data);
662 void (*free_non_pinned_object) (char *obj, size_t size);
663 void (*pin_objects) (SgenGrayQueue *queue);
664 void (*pin_major_object) (char *obj, SgenGrayQueue *queue);
665 void (*scan_card_table) (gboolean mod_union, ScanCopyContext ctx);
666 void (*iterate_live_block_ranges) (sgen_cardtable_block_callback callback);
667 void (*update_cardtable_mod_union) (void);
668 void (*init_to_space) (void);
669 void (*sweep) (void);
670 gboolean (*have_swept) (void);
671 void (*finish_sweeping) (void);
672 void (*free_swept_blocks) (size_t allowance);
673 void (*check_scan_starts) (void);
674 void (*dump_heap) (FILE *heap_dump_file);
675 gint64 (*get_used_size) (void);
676 void (*start_nursery_collection) (void);
677 void (*finish_nursery_collection) (void);
678 void (*start_major_collection) (void);
679 void (*finish_major_collection) (ScannedObjectCounts *counts);
680 gboolean (*drain_gray_stack) (ScanCopyContext ctx);
681 gboolean (*ptr_is_in_non_pinned_space) (char *ptr, char **start);
682 gboolean (*obj_is_from_pinned_alloc) (char *obj);
683 void (*report_pinned_memory_usage) (void);
684 size_t (*get_num_major_sections) (void);
685 size_t (*get_bytes_survived_last_sweep) (void);
686 gboolean (*handle_gc_param) (const char *opt);
687 void (*print_gc_param_usage) (void);
688 void (*post_param_init) (SgenMajorCollector *collector);
689 gboolean (*is_valid_object) (char *object);
690 GCVTable* (*describe_pointer) (char *pointer);
691 guint8* (*get_cardtable_mod_union_for_object) (char *object);
692 long long (*get_and_reset_num_major_objects_marked) (void);
693 void (*count_cards) (long long *num_total_cards, long long *num_marked_cards);
696 extern SgenMajorCollector major_collector;
698 void sgen_marksweep_init (SgenMajorCollector *collector);
699 void sgen_marksweep_fixed_init (SgenMajorCollector *collector);
700 void sgen_marksweep_par_init (SgenMajorCollector *collector);
701 void sgen_marksweep_fixed_par_init (SgenMajorCollector *collector);
702 void sgen_marksweep_conc_init (SgenMajorCollector *collector);
703 SgenMajorCollector* sgen_get_major_collector (void);
706 typedef struct _SgenRememberedSet {
707 void (*wbarrier_set_field) (MonoObject *obj, gpointer field_ptr, MonoObject* value);
708 void (*wbarrier_arrayref_copy) (gpointer dest_ptr, gpointer src_ptr, int count);
709 void (*wbarrier_value_copy) (gpointer dest, gpointer src, int count, size_t element_size);
710 void (*wbarrier_object_copy) (GCObject* obj, GCObject *src);
711 void (*wbarrier_generic_nostore) (gpointer ptr);
712 void (*record_pointer) (gpointer ptr);
714 void (*scan_remsets) (ScanCopyContext ctx);
716 void (*clear_cards) (void);
718 void (*finish_minor_collection) (void);
719 gboolean (*find_address) (char *addr);
720 gboolean (*find_address_with_cards) (char *cards_start, guint8 *cards, char *addr);
723 SgenRememberedSet *sgen_get_remset (void);
726 sgen_obj_get_descriptor (char *obj)
728 GCVTable *vtable = SGEN_LOAD_VTABLE_UNCHECKED (obj);
729 SGEN_ASSERT (9, !SGEN_POINTER_IS_TAGGED_ANY (vtable), "Object can't be tagged");
730 return sgen_vtable_get_descriptor (vtable);
734 sgen_obj_get_descriptor_safe (char *obj)
736 GCVTable *vtable = (GCVTable*)SGEN_LOAD_VTABLE (obj);
737 return sgen_vtable_get_descriptor (vtable);
741 sgen_safe_object_get_size (GCObject *obj)
745 if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj)))
746 obj = (GCObject*)forwarded;
748 return sgen_client_par_object_get_size ((GCVTable*)SGEN_LOAD_VTABLE (obj), obj);
751 static inline gboolean
752 sgen_safe_object_is_small (MonoObject *obj, int type)
754 if (type <= DESC_TYPE_MAX_SMALL_OBJ)
756 return SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)obj)) <= SGEN_MAX_SMALL_OBJ_SIZE;
760 * This variant guarantees to return the exact size of the object
761 * before alignment. Needed for canary support.
764 sgen_safe_object_get_size_unaligned (GCObject *obj)
768 if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj))) {
769 obj = (GCObject*)forwarded;
772 return sgen_client_slow_object_get_size ((GCVTable*)SGEN_LOAD_VTABLE (obj), obj);
775 #include "metadata/sgen-client-mono.h"
777 gboolean sgen_object_is_live (void *obj);
779 void sgen_init_fin_weak_hash (void);
781 gboolean sgen_need_bridge_processing (void);
782 void sgen_bridge_reset_data (void);
783 void sgen_bridge_processing_stw_step (void);
784 void sgen_bridge_processing_finish (int generation);
785 void sgen_register_test_bridge_callbacks (const char *bridge_class_name);
786 gboolean sgen_is_bridge_object (GCObject *obj);
787 MonoGCBridgeObjectKind sgen_bridge_class_kind (MonoClass *klass);
788 void sgen_mark_bridge_object (GCObject *obj);
789 void sgen_bridge_register_finalized_object (GCObject *object);
790 void sgen_bridge_describe_pointer (GCObject *object);
792 void sgen_mark_togglerefs (char *start, char *end, ScanCopyContext ctx);
793 void sgen_clear_togglerefs (char *start, char *end, ScanCopyContext ctx);
795 void sgen_process_togglerefs (void);
796 void sgen_register_test_toggleref_callback (void);
798 gboolean sgen_is_bridge_object (GCObject *obj);
799 void sgen_mark_bridge_object (GCObject *obj);
801 gboolean sgen_bridge_handle_gc_debug (const char *opt);
802 void sgen_bridge_print_gc_debug_usage (void);
805 void (*reset_data) (void);
806 void (*processing_stw_step) (void);
807 void (*processing_build_callback_data) (int generation);
808 void (*processing_after_callback) (int generation);
809 MonoGCBridgeObjectKind (*class_kind) (MonoClass *class);
810 void (*register_finalized_object) (GCObject *object);
811 void (*describe_pointer) (GCObject *object);
812 void (*enable_accounting) (void);
813 void (*set_dump_prefix) (const char *prefix);
816 * These are set by processing_build_callback_data().
819 MonoGCBridgeSCC **api_sccs;
822 MonoGCBridgeXRef *api_xrefs;
823 } SgenBridgeProcessor;
825 void sgen_old_bridge_init (SgenBridgeProcessor *collector);
826 void sgen_new_bridge_init (SgenBridgeProcessor *collector);
827 void sgen_tarjan_bridge_init (SgenBridgeProcessor *collector);
828 void sgen_set_bridge_implementation (const char *name);
829 void sgen_bridge_set_dump_prefix (const char *prefix);
831 gboolean sgen_compare_bridge_processor_results (SgenBridgeProcessor *a, SgenBridgeProcessor *b);
833 typedef mono_bool (*WeakLinkAlivePredicateFunc) (GCObject*, void*);
835 void sgen_null_links_with_predicate (int generation, WeakLinkAlivePredicateFunc predicate, void *data);
837 gboolean sgen_gc_is_object_ready_for_finalization (void *object);
838 void sgen_gc_lock (void);
839 void sgen_gc_unlock (void);
841 void sgen_queue_finalization_entry (GCObject *obj);
842 const char* sgen_generation_name (int generation);
844 void sgen_collect_bridge_objects (int generation, ScanCopyContext ctx);
845 void sgen_finalize_in_range (int generation, ScanCopyContext ctx);
846 void sgen_null_link_in_range (int generation, gboolean before_finalization, ScanCopyContext ctx);
847 void sgen_null_links_for_domain (MonoDomain *domain, int generation);
848 void sgen_remove_finalizers_for_domain (MonoDomain *domain, int generation);
849 void sgen_process_fin_stage_entries (void);
850 void sgen_process_dislink_stage_entries (void);
851 void sgen_register_disappearing_link (GCObject *obj, void **link, gboolean track, gboolean in_gc);
853 gboolean sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx);
861 void sgen_pin_object (void *object, SgenGrayQueue *queue);
862 void sgen_set_pinned_from_failed_allocation (mword objsize);
864 void sgen_ensure_free_space (size_t size);
865 void sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish);
866 gboolean sgen_has_critical_method (void);
867 gboolean sgen_is_critical_method (MonoMethod *method);
874 gboolean is_overflow;
875 SGEN_TV_DECLARE (total_time);
876 SGEN_TV_DECLARE (stw_time);
877 SGEN_TV_DECLARE (bridge_time);
880 int sgen_stop_world (int generation);
881 int sgen_restart_world (int generation, GGTimingInfo *timing);
882 gboolean sgen_is_world_stopped (void);
886 typedef struct _LOSObject LOSObject;
889 mword size; /* this is the object size, lowest bit used for pin/mark */
890 guint8 * volatile cardtable_mod_union; /* only used by the concurrent collector */
891 #if SIZEOF_VOID_P < 8
892 mword dummy; /* to align object to sizeof (double) */
894 char data [MONO_ZERO_LEN_ARRAY];
897 extern LOSObject *los_object_list;
898 extern mword los_memory_usage;
900 void sgen_los_free_object (LOSObject *obj);
901 void* sgen_los_alloc_large_inner (GCVTable *vtable, size_t size);
902 void sgen_los_sweep (void);
903 gboolean sgen_ptr_is_in_los (char *ptr, char **start);
904 void sgen_los_iterate_objects (IterateObjectCallbackFunc cb, void *user_data);
905 void sgen_los_iterate_live_block_ranges (sgen_cardtable_block_callback callback);
906 void sgen_los_scan_card_table (gboolean mod_union, ScanCopyContext ctx);
907 void sgen_los_update_cardtable_mod_union (void);
908 void sgen_los_count_cards (long long *num_total_cards, long long *num_marked_cards);
909 gboolean sgen_los_is_valid_object (char *object);
910 gboolean mono_sgen_los_describe_pointer (char *ptr);
911 LOSObject* sgen_los_header_for_object (char *data);
912 mword sgen_los_object_size (LOSObject *obj);
913 void sgen_los_pin_object (char *obj);
914 gboolean sgen_los_object_is_pinned (char *obj);
915 void sgen_los_mark_mod_union_card (MonoObject *mono_obj, void **ptr);
918 /* nursery allocator */
920 void sgen_clear_nursery_fragments (void);
921 void sgen_nursery_allocator_prepare_for_pinning (void);
922 void sgen_nursery_allocator_set_nursery_bounds (char *nursery_start, char *nursery_end);
923 mword sgen_build_nursery_fragments (GCMemSection *nursery_section, SgenGrayQueue *unpin_queue);
924 void sgen_init_nursery_allocator (void);
925 void sgen_nursery_allocator_init_heavy_stats (void);
926 void sgen_init_allocator (void);
927 char* sgen_nursery_alloc_get_upper_alloc_bound (void);
928 void* sgen_nursery_alloc (size_t size);
929 void* sgen_nursery_alloc_range (size_t size, size_t min_size, size_t *out_alloc_size);
930 gboolean sgen_can_alloc_size (size_t size);
931 void sgen_nursery_retire_region (void *address, ptrdiff_t size);
933 void sgen_nursery_alloc_prepare_for_minor (void);
934 void sgen_nursery_alloc_prepare_for_major (void);
936 char* sgen_alloc_for_promotion (char *obj, size_t objsize, gboolean has_references);
938 void* sgen_alloc_obj_nolock (GCVTable *vtable, size_t size);
939 void* sgen_try_alloc_obj_nolock (GCVTable *vtable, size_t size);
943 void* sgen_thread_register (SgenThreadInfo* info, void *addr);
944 void sgen_thread_unregister (SgenThreadInfo *p);
945 void sgen_thread_attach (SgenThreadInfo *info);
947 /* Finalization/ephemeron support */
949 static inline gboolean
950 sgen_major_is_object_alive (void *object)
954 /* Oldgen objects can be pinned and forwarded too */
955 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
959 * FIXME: major_collector.is_object_live() also calculates the
960 * size. Avoid the double calculation.
962 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((GCObject*)object));
963 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
964 return sgen_los_object_is_pinned (object);
966 return major_collector.is_object_live (object);
970 * This function returns true if @object is either alive or it belongs to the old gen
971 * and we're currently doing a minor collection.
974 sgen_is_object_alive_for_current_gen (char *object)
976 if (sgen_ptr_in_nursery (object))
977 return sgen_nursery_is_object_alive (object);
979 if (current_collection_generation == GENERATION_NURSERY)
982 return sgen_major_is_object_alive (object);
987 extern MonoNativeTlsKey thread_info_key;
989 #ifdef HAVE_KW_THREAD
990 extern __thread SgenThreadInfo *sgen_thread_info;
991 extern __thread char *stack_end;
994 #ifdef HAVE_KW_THREAD
995 #define TLAB_ACCESS_INIT
996 #define IN_CRITICAL_REGION sgen_thread_info->in_critical_region
998 #define TLAB_ACCESS_INIT SgenThreadInfo *__thread_info__ = mono_native_tls_get_value (thread_info_key)
999 #define IN_CRITICAL_REGION (__thread_info__->in_critical_region)
1002 #ifndef DISABLE_CRITICAL_REGION
1004 #ifdef HAVE_KW_THREAD
1005 #define IN_CRITICAL_REGION sgen_thread_info->in_critical_region
1007 #define IN_CRITICAL_REGION (__thread_info__->in_critical_region)
1010 /* Enter must be visible before anything is done in the critical region. */
1011 #define ENTER_CRITICAL_REGION do { mono_atomic_store_acquire (&IN_CRITICAL_REGION, 1); } while (0)
1013 /* Exit must make sure all critical regions stores are visible before it signal the end of the region.
1014 * We don't need to emit a full barrier since we
1016 #define EXIT_CRITICAL_REGION do { mono_atomic_store_release (&IN_CRITICAL_REGION, 0); } while (0)
1022 extern GCMemSection *nursery_section;
1023 extern guint32 collect_before_allocs;
1024 extern guint32 verify_before_allocs;
1025 extern gboolean has_per_allocation_action;
1026 extern size_t degraded_mode;
1027 extern int default_nursery_size;
1028 extern guint32 tlab_size;
1029 extern NurseryClearPolicy nursery_clear_policy;
1030 extern gboolean sgen_try_free_some_memory;
1032 extern LOCK_DECLARE (gc_mutex);
1034 /* Nursery helpers. */
1037 sgen_set_nursery_scan_start (char *p)
1039 size_t idx = (p - (char*)nursery_section->data) / SGEN_SCAN_START_SIZE;
1040 char *old = nursery_section->scan_starts [idx];
1041 if (!old || old > p)
1042 nursery_section->scan_starts [idx] = p;
1046 /* Object Allocation */
1054 } SgenAllocatorType;
1056 void sgen_init_tlab_info (SgenThreadInfo* info);
1057 void sgen_clear_tlabs (void);
1058 void sgen_set_use_managed_allocator (gboolean flag);
1059 gboolean sgen_is_managed_allocator (MonoMethod *method);
1060 gboolean sgen_has_managed_allocator (void);
1064 void sgen_check_consistency (void);
1065 void sgen_check_mod_union_consistency (void);
1066 void sgen_check_major_refs (void);
1067 void sgen_check_whole_heap (gboolean allow_missing_pinning);
1068 void sgen_check_whole_heap_stw (void);
1069 void sgen_check_objref (char *obj);
1070 void sgen_check_heap_marked (gboolean nursery_must_be_pinned);
1071 void sgen_check_nursery_objects_pinned (gboolean pinned);
1072 void sgen_scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type);
1073 void sgen_check_for_xdomain_refs (void);
1074 char* sgen_find_object_for_ptr (char *ptr);
1076 void mono_gc_scan_for_specific_ref (GCObject *key, gboolean precise);
1078 void sgen_debug_enable_heap_dump (const char *filename);
1079 void sgen_debug_dump_heap (const char *type, int num, const char *reason);
1081 void sgen_debug_verify_nursery (gboolean do_dump_nursery_content);
1082 void sgen_debug_check_nursery_is_clean (void);
1084 /* Write barrier support */
1087 * This causes the compile to extend the liveness of 'v' till the call to dummy_use
1090 sgen_dummy_use (gpointer v) {
1091 #if defined(__GNUC__)
1092 __asm__ volatile ("" : "=r"(v) : "r"(v));
1093 #elif defined(_MSC_VER)
1094 static volatile gpointer ptr;
1097 #error "Implement sgen_dummy_use for your compiler"
1101 /* Environment variable parsing */
1103 #define MONO_GC_PARAMS_NAME "MONO_GC_PARAMS"
1104 #define MONO_GC_DEBUG_NAME "MONO_GC_DEBUG"
1106 gboolean sgen_parse_environment_string_extract_number (const char *str, size_t *out);
1107 void sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...);
1111 void sgen_qsort (void *base, size_t nel, size_t width, int (*compar) (const void*, const void*));
1112 gint64 sgen_timestamp (void);
1115 * Canary (guard word) support
1117 * - CANARY_SIZE must be multiple of word size in bytes
1118 * - Canary space is not included on checks against SGEN_MAX_SMALL_OBJ_SIZE
1121 gboolean nursery_canaries_enabled (void);
1123 #define CANARY_SIZE 8
1124 #define CANARY_STRING "koupepia"
1126 #define CANARIFY_SIZE(size) if (nursery_canaries_enabled ()) { \
1127 size = size + CANARY_SIZE; \
1130 #define CANARIFY_ALLOC(addr,size) if (nursery_canaries_enabled ()) { \
1131 memcpy ((char*) (addr) + (size), CANARY_STRING, CANARY_SIZE); \
1134 #define CANARY_VALID(addr) (strncmp ((char*) (addr), CANARY_STRING, CANARY_SIZE) == 0)
1136 #define CHECK_CANARY_FOR_OBJECT(addr) if (nursery_canaries_enabled ()) { \
1137 char* canary_ptr = (char*) (addr) + sgen_safe_object_get_size_unaligned ((GCObject *) (addr)); \
1138 if (!CANARY_VALID(canary_ptr)) { \
1139 char canary_copy[CANARY_SIZE +1]; \
1140 strncpy (canary_copy, canary_ptr, CANARY_SIZE); \
1141 canary_copy[CANARY_SIZE] = 0; \
1142 g_error ("CORRUPT CANARY:\naddr->%p\ntype->%s\nexcepted->'%s'\nfound->'%s'\n", (char*) addr, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE ((addr))), CANARY_STRING, canary_copy); \
1145 #endif /* HAVE_SGEN_GC */
1147 #endif /* __MONO_SGENGC_H__ */