2 * sgen-gc.c: Simple generational GC.
5 * Paolo Molaro (lupus@ximian.com)
6 * Rodrigo Kumpera (kumpera@gmail.com)
8 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
9 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
11 * Thread start/stop adapted from Boehm's GC:
12 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
13 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
14 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
15 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
17 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
18 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
20 * Permission is hereby granted to use or copy this program
21 * for any purpose, provided the above notices are retained on all copies.
22 * Permission to modify the code and to distribute modified code is granted,
23 * provided the above notices are retained, and a notice that the code was
24 * modified is included with the above copyright notice.
27 * Copyright 2001-2003 Ximian, Inc
28 * Copyright 2003-2010 Novell, Inc.
29 * Copyright 2011 Xamarin, Inc.
31 * Permission is hereby granted, free of charge, to any person obtaining
32 * a copy of this software and associated documentation files (the
33 * "Software"), to deal in the Software without restriction, including
34 * without limitation the rights to use, copy, modify, merge, publish,
35 * distribute, sublicense, and/or sell copies of the Software, and to
36 * permit persons to whom the Software is furnished to do so, subject to
37 * the following conditions:
39 * The above copyright notice and this permission notice shall be
40 * included in all copies or substantial portions of the Software.
42 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
43 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
44 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
45 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
46 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
47 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
48 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
51 * Important: allocation provides always zeroed memory, having to do
52 * a memset after allocation is deadly for performance.
53 * Memory usage at startup is currently as follows:
55 * 64 KB internal space
57 * We should provide a small memory config with half the sizes
59 * We currently try to make as few mono assumptions as possible:
60 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
62 * 2) gc descriptor is the second word in the vtable (first word in the class)
63 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
64 * 4) there is a function to get an object's size and the number of
65 * elements in an array.
66 * 5) we know the special way bounds are allocated for complex arrays
67 * 6) we know about proxies and how to treat them when domains are unloaded
69 * Always try to keep stack usage to a minimum: no recursive behaviour
70 * and no large stack allocs.
72 * General description.
73 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
74 * When the nursery is full we start a nursery collection: this is performed with a
76 * When the old generation is full we start a copying GC of the old generation as well:
77 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
78 * in the future. Maybe we'll even do both during the same collection like IMMIX.
80 * The things that complicate this description are:
81 * *) pinned objects: we can't move them so we need to keep track of them
82 * *) no precise info of the thread stacks and registers: we need to be able to
83 * quickly find the objects that may be referenced conservatively and pin them
84 * (this makes the first issues more important)
85 * *) large objects are too expensive to be dealt with using copying GC: we handle them
86 * with mark/sweep during major collections
87 * *) some objects need to not move even if they are small (interned strings, Type handles):
88 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
89 * PinnedChunks regions
95 *) we could have a function pointer in MonoClass to implement
96 customized write barriers for value types
98 *) investigate the stuff needed to advance a thread to a GC-safe
99 point (single-stepping, read from unmapped memory etc) and implement it.
100 This would enable us to inline allocations and write barriers, for example,
101 or at least parts of them, like the write barrier checks.
102 We may need this also for handling precise info on stacks, even simple things
103 as having uninitialized data on the stack and having to wait for the prolog
104 to zero it. Not an issue for the last frame that we scan conservatively.
105 We could always not trust the value in the slots anyway.
107 *) modify the jit to save info about references in stack locations:
108 this can be done just for locals as a start, so that at least
109 part of the stack is handled precisely.
111 *) test/fix endianess issues
113 *) Implement a card table as the write barrier instead of remembered
114 sets? Card tables are not easy to implement with our current
115 memory layout. We have several different kinds of major heap
116 objects: Small objects in regular blocks, small objects in pinned
117 chunks and LOS objects. If we just have a pointer we have no way
118 to tell which kind of object it points into, therefore we cannot
119 know where its card table is. The least we have to do to make
120 this happen is to get rid of write barriers for indirect stores.
123 *) Get rid of write barriers for indirect stores. We can do this by
124 telling the GC to wbarrier-register an object once we do an ldloca
125 or ldelema on it, and to unregister it once it's not used anymore
126 (it can only travel downwards on the stack). The problem with
127 unregistering is that it needs to happen eventually no matter
128 what, even if exceptions are thrown, the thread aborts, etc.
129 Rodrigo suggested that we could do only the registering part and
130 let the collector find out (pessimistically) when it's safe to
131 unregister, namely when the stack pointer of the thread that
132 registered the object is higher than it was when the registering
133 happened. This might make for a good first implementation to get
134 some data on performance.
136 *) Some sort of blacklist support? Blacklists is a concept from the
137 Boehm GC: if during a conservative scan we find pointers to an
138 area which we might use as heap, we mark that area as unusable, so
139 pointer retention by random pinning pointers is reduced.
141 *) experiment with max small object size (very small right now - 2kb,
142 because it's tied to the max freelist size)
144 *) add an option to mmap the whole heap in one chunk: it makes for many
145 simplifications in the checks (put the nursery at the top and just use a single
146 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
147 not flexible (too much of the address space may be used by default or we can't
148 increase the heap as needed) and we'd need a race-free mechanism to return memory
149 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
150 was written to, munmap is needed, but the following mmap may not find the same segment
153 *) memzero the major fragments after restarting the world and optionally a smaller
156 *) investigate having fragment zeroing threads
158 *) separate locks for finalization and other minor stuff to reduce
161 *) try a different copying order to improve memory locality
163 *) a thread abort after a store but before the write barrier will
164 prevent the write barrier from executing
166 *) specialized dynamically generated markers/copiers
168 *) Dynamically adjust TLAB size to the number of threads. If we have
169 too many threads that do allocation, we might need smaller TLABs,
170 and we might get better performance with larger TLABs if we only
171 have a handful of threads. We could sum up the space left in all
172 assigned TLABs and if that's more than some percentage of the
173 nursery size, reduce the TLAB size.
175 *) Explore placing unreachable objects on unused nursery memory.
176 Instead of memset'ng a region to zero, place an int[] covering it.
177 A good place to start is add_nursery_frag. The tricky thing here is
178 placing those objects atomically outside of a collection.
180 *) Allocation should use asymmetric Dekker synchronization:
181 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
182 This should help weak consistency archs.
189 #define _XOPEN_SOURCE
190 #define _DARWIN_C_SOURCE
196 #ifdef HAVE_PTHREAD_H
199 #ifdef HAVE_SEMAPHORE_H
200 #include <semaphore.h>
208 #include "metadata/sgen-gc.h"
209 #include "metadata/metadata-internals.h"
210 #include "metadata/class-internals.h"
211 #include "metadata/gc-internal.h"
212 #include "metadata/object-internals.h"
213 #include "metadata/threads.h"
214 #include "metadata/sgen-cardtable.h"
215 #include "metadata/sgen-ssb.h"
216 #include "metadata/sgen-protocol.h"
217 #include "metadata/sgen-archdep.h"
218 #include "metadata/sgen-bridge.h"
219 #include "metadata/mono-gc.h"
220 #include "metadata/method-builder.h"
221 #include "metadata/profiler-private.h"
222 #include "metadata/monitor.h"
223 #include "metadata/threadpool-internals.h"
224 #include "metadata/mempool-internals.h"
225 #include "metadata/marshal.h"
226 #include "metadata/runtime.h"
227 #include "metadata/sgen-cardtable.h"
228 #include "metadata/sgen-pinning.h"
229 #include "metadata/sgen-workers.h"
230 #include "utils/mono-mmap.h"
231 #include "utils/mono-time.h"
232 #include "utils/mono-semaphore.h"
233 #include "utils/mono-counters.h"
234 #include "utils/mono-proclib.h"
235 #include "utils/mono-memory-model.h"
236 #include "utils/mono-logger-internal.h"
238 #include <mono/utils/mono-logger-internal.h>
239 #include <mono/utils/memcheck.h>
241 #if defined(__MACH__)
242 #include "utils/mach-support.h"
245 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
249 #include "mono/cil/opcode.def"
255 #undef pthread_create
257 #undef pthread_detach
260 * ######################################################################
261 * ######## Types and constants used by the GC.
262 * ######################################################################
265 /* 0 means not initialized, 1 is initialized, -1 means in progress */
266 static int gc_initialized = 0;
267 /* If set, check if we need to do something every X allocations */
268 gboolean has_per_allocation_action;
269 /* If set, do a heap check every X allocation */
270 guint32 verify_before_allocs = 0;
271 /* If set, do a minor collection before every X allocation */
272 guint32 collect_before_allocs = 0;
273 /* If set, do a whole heap check before each collection */
274 static gboolean whole_heap_check_before_collection = FALSE;
275 /* If set, do a heap consistency check before each minor collection */
276 static gboolean consistency_check_at_minor_collection = FALSE;
277 /* If set, check that there are no references to the domain left at domain unload */
278 static gboolean xdomain_checks = FALSE;
279 /* If not null, dump the heap after each collection into this file */
280 static FILE *heap_dump_file = NULL;
281 /* If set, mark stacks conservatively, even if precise marking is possible */
282 static gboolean conservative_stack_mark = FALSE;
283 /* If set, do a plausibility check on the scan_starts before and after
285 static gboolean do_scan_starts_check = FALSE;
286 static gboolean nursery_collection_is_parallel = FALSE;
287 static gboolean disable_minor_collections = FALSE;
288 static gboolean disable_major_collections = FALSE;
289 gboolean do_pin_stats = FALSE;
290 static gboolean do_verify_nursery = FALSE;
291 static gboolean do_dump_nursery_content = FALSE;
293 #ifdef HEAVY_STATISTICS
294 long long stat_objects_alloced_degraded = 0;
295 long long stat_bytes_alloced_degraded = 0;
297 long long stat_copy_object_called_nursery = 0;
298 long long stat_objects_copied_nursery = 0;
299 long long stat_copy_object_called_major = 0;
300 long long stat_objects_copied_major = 0;
302 long long stat_scan_object_called_nursery = 0;
303 long long stat_scan_object_called_major = 0;
305 long long stat_slots_allocated_in_vain;
307 long long stat_nursery_copy_object_failed_from_space = 0;
308 long long stat_nursery_copy_object_failed_forwarded = 0;
309 long long stat_nursery_copy_object_failed_pinned = 0;
310 long long stat_nursery_copy_object_failed_to_space = 0;
312 static int stat_wbarrier_set_field = 0;
313 static int stat_wbarrier_set_arrayref = 0;
314 static int stat_wbarrier_arrayref_copy = 0;
315 static int stat_wbarrier_generic_store = 0;
316 static int stat_wbarrier_set_root = 0;
317 static int stat_wbarrier_value_copy = 0;
318 static int stat_wbarrier_object_copy = 0;
321 int stat_minor_gcs = 0;
322 int stat_major_gcs = 0;
324 static long long stat_pinned_objects = 0;
326 static long long time_minor_pre_collection_fragment_clear = 0;
327 static long long time_minor_pinning = 0;
328 static long long time_minor_scan_remsets = 0;
329 static long long time_minor_scan_pinned = 0;
330 static long long time_minor_scan_registered_roots = 0;
331 static long long time_minor_scan_thread_data = 0;
332 static long long time_minor_finish_gray_stack = 0;
333 static long long time_minor_fragment_creation = 0;
335 static long long time_major_pre_collection_fragment_clear = 0;
336 static long long time_major_pinning = 0;
337 static long long time_major_scan_pinned = 0;
338 static long long time_major_scan_registered_roots = 0;
339 static long long time_major_scan_thread_data = 0;
340 static long long time_major_scan_alloc_pinned = 0;
341 static long long time_major_scan_finalized = 0;
342 static long long time_major_scan_big_objects = 0;
343 static long long time_major_finish_gray_stack = 0;
344 static long long time_major_free_bigobjs = 0;
345 static long long time_major_los_sweep = 0;
346 static long long time_major_sweep = 0;
347 static long long time_major_fragment_creation = 0;
349 int gc_debug_level = 0;
351 static gboolean debug_print_allowance = FALSE;
355 mono_gc_flush_info (void)
357 fflush (gc_debug_file);
361 #define TV_DECLARE SGEN_TV_DECLARE
362 #define TV_GETTIME SGEN_TV_GETTIME
363 #define TV_ELAPSED SGEN_TV_ELAPSED
364 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
366 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
368 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
370 /* the runtime can register areas of memory as roots: we keep two lists of roots,
371 * a pinned root set for conservatively scanned roots and a normal one for
372 * precisely scanned roots (currently implemented as a single list).
374 typedef struct _RootRecord RootRecord;
380 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
381 #define object_is_pinned SGEN_OBJECT_IS_PINNED
382 #define pin_object SGEN_PIN_OBJECT
383 #define unpin_object SGEN_UNPIN_OBJECT
385 #define ptr_in_nursery sgen_ptr_in_nursery
387 #define LOAD_VTABLE SGEN_LOAD_VTABLE
390 safe_name (void* obj)
392 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
393 return vt->klass->name;
396 #define safe_object_get_size sgen_safe_object_get_size
399 sgen_safe_name (void* obj)
401 return safe_name (obj);
405 * ######################################################################
406 * ######## Global data.
407 * ######################################################################
409 LOCK_DECLARE (gc_mutex);
410 static int gc_disabled = 0;
412 static gboolean use_cardtable;
414 #define MIN_MINOR_COLLECTION_ALLOWANCE (DEFAULT_NURSERY_SIZE * 4)
416 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
418 static mword pagesize = 4096;
419 int degraded_mode = 0;
421 static mword bytes_pinned_from_failed_allocation = 0;
423 static mword total_alloc = 0;
424 /* use this to tune when to do a major/minor collection */
425 static mword memory_pressure = 0;
426 static mword minor_collection_allowance;
427 static int minor_collection_sections_alloced = 0;
430 /* GC Logging stats */
431 static int last_major_num_sections = 0;
432 static int last_los_memory_usage = 0;
433 static gboolean major_collection_happened = FALSE;
435 GCMemSection *nursery_section = NULL;
436 static mword lowest_heap_address = ~(mword)0;
437 static mword highest_heap_address = 0;
439 static LOCK_DECLARE (interruption_mutex);
440 static LOCK_DECLARE (pin_queue_mutex);
442 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
443 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
445 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
446 struct _FinalizeReadyEntry {
447 FinalizeReadyEntry *next;
451 typedef struct _EphemeronLinkNode EphemeronLinkNode;
453 struct _EphemeronLinkNode {
454 EphemeronLinkNode *next;
463 int current_collection_generation = -1;
466 * The link pointer is hidden by negating each bit. We use the lowest
467 * bit of the link (before negation) to store whether it needs
468 * resurrection tracking.
470 #define HIDE_POINTER(p,t) ((gpointer)(~((gulong)(p)|((t)?1:0))))
471 #define REVEAL_POINTER(p) ((gpointer)((~(gulong)(p))&~3L))
473 /* objects that are ready to be finalized */
474 static FinalizeReadyEntry *fin_ready_list = NULL;
475 static FinalizeReadyEntry *critical_fin_list = NULL;
477 static EphemeronLinkNode *ephemeron_list;
479 static int num_ready_finalizers = 0;
480 static int no_finalize = 0;
483 ROOT_TYPE_NORMAL = 0, /* "normal" roots */
484 ROOT_TYPE_PINNED = 1, /* roots without a GC descriptor */
485 ROOT_TYPE_WBARRIER = 2, /* roots with a write barrier */
489 /* registered roots: the key to the hash is the root start address */
491 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
493 static SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
494 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
495 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
496 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
498 static mword roots_size = 0; /* amount of memory in the root set */
500 #define GC_ROOT_NUM 32
503 void *objects [GC_ROOT_NUM];
504 int root_types [GC_ROOT_NUM];
505 uintptr_t extra_info [GC_ROOT_NUM];
509 notify_gc_roots (GCRootReport *report)
513 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
518 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
520 if (report->count == GC_ROOT_NUM)
521 notify_gc_roots (report);
522 report->objects [report->count] = object;
523 report->root_types [report->count] = rtype;
524 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
527 MonoNativeTlsKey thread_info_key;
529 #ifdef HAVE_KW_THREAD
530 __thread SgenThreadInfo *thread_info;
531 __thread gpointer *store_remset_buffer;
532 __thread long store_remset_buffer_index;
533 __thread char *stack_end;
534 __thread long *store_remset_buffer_index_addr;
537 /* The size of a TLAB */
538 /* The bigger the value, the less often we have to go to the slow path to allocate a new
539 * one, but the more space is wasted by threads not allocating much memory.
541 * FIXME: Make this self-tuning for each thread.
543 guint32 tlab_size = (1024 * 4);
545 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
547 /* Functions supplied by the runtime to be called by the GC */
548 static MonoGCCallbacks gc_callbacks;
550 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
551 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
553 #define ALIGN_UP SGEN_ALIGN_UP
555 #define MOVED_OBJECTS_NUM 64
556 static void *moved_objects [MOVED_OBJECTS_NUM];
557 static int moved_objects_idx = 0;
559 /* Vtable of the objects used to fill out nursery fragments before a collection */
560 static MonoVTable *array_fill_vtable;
562 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
563 MonoNativeThreadId main_gc_thread = NULL;
567 * ######################################################################
568 * ######## Heap size accounting
569 * ######################################################################
572 static mword max_heap_size = ((mword)0)- ((mword)1);
573 static mword soft_heap_limit = ((mword)0) - ((mword)1);
574 static mword allocated_heap;
576 /*Object was pinned during the current collection*/
577 static mword objects_pinned;
580 sgen_release_space (mword size, int space)
582 allocated_heap -= size;
586 available_free_space (void)
588 return max_heap_size - MIN (allocated_heap, max_heap_size);
592 sgen_try_alloc_space (mword size, int space)
594 if (available_free_space () < size)
597 allocated_heap += size;
598 mono_runtime_resource_check_limit (MONO_RESOURCE_GC_HEAP, allocated_heap);
603 init_heap_size_limits (glong max_heap, glong soft_limit)
606 soft_heap_limit = soft_limit;
611 if (max_heap < soft_limit) {
612 fprintf (stderr, "max-heap-size must be at least as large as soft-heap-limit.\n");
616 if (max_heap < sgen_nursery_size * 4) {
617 fprintf (stderr, "max-heap-size must be at least 4 times larger than nursery size.\n");
620 max_heap_size = max_heap - sgen_nursery_size;
624 * ######################################################################
625 * ######## Macros and function declarations.
626 * ######################################################################
630 align_pointer (void *ptr)
632 mword p = (mword)ptr;
633 p += sizeof (gpointer) - 1;
634 p &= ~ (sizeof (gpointer) - 1);
638 typedef SgenGrayQueue GrayQueue;
640 /* forward declarations */
641 static int stop_world (int generation);
642 static int restart_world (int generation);
643 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
644 static void scan_from_registered_roots (CopyOrMarkObjectFunc copy_func, char *addr_start, char *addr_end, int root_type, GrayQueue *queue);
645 static void scan_finalizer_entries (CopyOrMarkObjectFunc copy_func, FinalizeReadyEntry *list, GrayQueue *queue);
646 static void report_finalizer_roots (void);
647 static void report_registered_roots (void);
648 static void find_pinning_ref_from_thread (char *obj, size_t size);
649 static void update_current_thread_stack (void *start);
650 static void collect_bridge_objects (CopyOrMarkObjectFunc copy_func, char *start, char *end, int generation, GrayQueue *queue);
651 static void finalize_in_range (CopyOrMarkObjectFunc copy_func, char *start, char *end, int generation, GrayQueue *queue);
652 static void process_fin_stage_entries (void);
653 static void null_link_in_range (CopyOrMarkObjectFunc copy_func, char *start, char *end, int generation, gboolean before_finalization, GrayQueue *queue);
654 static void null_links_for_domain (MonoDomain *domain, int generation);
655 static void remove_finalizers_for_domain (MonoDomain *domain, int generation);
656 static void process_dislink_stage_entries (void);
658 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
659 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, GrayQueue *queue);
660 static void finish_gray_stack (char *start_addr, char *end_addr, int generation, GrayQueue *queue);
661 static gboolean need_major_collection (mword space_needed);
662 static void major_collection (const char *reason);
664 static void mono_gc_register_disappearing_link (MonoObject *obj, void **link, gboolean track, gboolean in_gc);
665 static gboolean mono_gc_is_critical_method (MonoMethod *method);
667 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
670 static void init_stats (void);
672 static int mark_ephemerons_in_range (CopyOrMarkObjectFunc copy_func, char *start, char *end, GrayQueue *queue);
673 static void clear_unreachable_ephemerons (CopyOrMarkObjectFunc copy_func, char *start, char *end, GrayQueue *queue);
674 static void null_ephemerons_for_domain (MonoDomain *domain);
676 SgenObjectOperations current_object_ops;
677 SgenMajorCollector major_collector;
678 SgenMinorCollector sgen_minor_collector;
679 static GrayQueue gray_queue;
681 static SgenRemeberedSet remset;
684 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (sgen_collection_is_parallel () ? sgen_workers_get_distribute_gray_queue () : &gray_queue)
686 static SgenGrayQueue*
687 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
689 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
693 is_xdomain_ref_allowed (gpointer *ptr, char *obj, MonoDomain *domain)
695 MonoObject *o = (MonoObject*)(obj);
696 MonoObject *ref = (MonoObject*)*(ptr);
697 int offset = (char*)(ptr) - (char*)o;
699 if (o->vtable->klass == mono_defaults.thread_class && offset == G_STRUCT_OFFSET (MonoThread, internal_thread))
701 if (o->vtable->klass == mono_defaults.internal_thread_class && offset == G_STRUCT_OFFSET (MonoInternalThread, current_appcontext))
703 if (mono_class_has_parent_fast (o->vtable->klass, mono_defaults.real_proxy_class) &&
704 offset == G_STRUCT_OFFSET (MonoRealProxy, unwrapped_server))
706 /* Thread.cached_culture_info */
707 if (!strcmp (ref->vtable->klass->name_space, "System.Globalization") &&
708 !strcmp (ref->vtable->klass->name, "CultureInfo") &&
709 !strcmp(o->vtable->klass->name_space, "System") &&
710 !strcmp(o->vtable->klass->name, "Object[]"))
713 * at System.IO.MemoryStream.InternalConstructor (byte[],int,int,bool,bool) [0x0004d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:121
714 * at System.IO.MemoryStream..ctor (byte[]) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.IO/MemoryStream.cs:81
715 * at (wrapper remoting-invoke-with-check) System.IO.MemoryStream..ctor (byte[]) <IL 0x00020, 0xffffffff>
716 * at System.Runtime.Remoting.Messaging.CADMethodCallMessage.GetArguments () [0x0000d] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/CADMessages.cs:327
717 * at System.Runtime.Remoting.Messaging.MethodCall..ctor (System.Runtime.Remoting.Messaging.CADMethodCallMessage) [0x00017] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Messaging/MethodCall.cs:87
718 * at System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) [0x00018] in /home/schani/Work/novell/trunk/mcs/class/corlib/System/AppDomain.cs:1213
719 * at (wrapper remoting-invoke-with-check) System.AppDomain.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage,byte[]&,System.Runtime.Remoting.Messaging.CADMethodReturnMessage&) <IL 0x0003d, 0xffffffff>
720 * at System.Runtime.Remoting.Channels.CrossAppDomainSink.ProcessMessageInDomain (byte[],System.Runtime.Remoting.Messaging.CADMethodCallMessage) [0x00008] in /home/schani/Work/novell/trunk/mcs/class/corlib/System.Runtime.Remoting.Channels/CrossAppDomainChannel.cs:198
721 * at (wrapper runtime-invoke) object.runtime_invoke_CrossAppDomainSink/ProcessMessageRes_object_object (object,intptr,intptr,intptr) <IL 0x0004c, 0xffffffff>
723 if (!strcmp (ref->vtable->klass->name_space, "System") &&
724 !strcmp (ref->vtable->klass->name, "Byte[]") &&
725 !strcmp (o->vtable->klass->name_space, "System.IO") &&
726 !strcmp (o->vtable->klass->name, "MemoryStream"))
728 /* append_job() in threadpool.c */
729 if (!strcmp (ref->vtable->klass->name_space, "System.Runtime.Remoting.Messaging") &&
730 !strcmp (ref->vtable->klass->name, "AsyncResult") &&
731 !strcmp (o->vtable->klass->name_space, "System") &&
732 !strcmp (o->vtable->klass->name, "Object[]") &&
733 mono_thread_pool_is_queue_array ((MonoArray*) o))
739 check_reference_for_xdomain (gpointer *ptr, char *obj, MonoDomain *domain)
741 MonoObject *o = (MonoObject*)(obj);
742 MonoObject *ref = (MonoObject*)*(ptr);
743 int offset = (char*)(ptr) - (char*)o;
745 MonoClassField *field;
748 if (!ref || ref->vtable->domain == domain)
750 if (is_xdomain_ref_allowed (ptr, obj, domain))
754 for (class = o->vtable->klass; class; class = class->parent) {
757 for (i = 0; i < class->field.count; ++i) {
758 if (class->fields[i].offset == offset) {
759 field = &class->fields[i];
767 if (ref->vtable->klass == mono_defaults.string_class)
768 str = mono_string_to_utf8 ((MonoString*)ref);
771 g_print ("xdomain reference in %p (%s.%s) at offset %d (%s) to %p (%s.%s) (%s) - pointed to by:\n",
772 o, o->vtable->klass->name_space, o->vtable->klass->name,
773 offset, field ? field->name : "",
774 ref, ref->vtable->klass->name_space, ref->vtable->klass->name, str ? str : "");
775 mono_gc_scan_for_specific_ref (o, TRUE);
781 #define HANDLE_PTR(ptr,obj) check_reference_for_xdomain ((ptr), (obj), domain)
784 scan_object_for_xdomain_refs (char *start, mword size, void *data)
786 MonoDomain *domain = ((MonoObject*)start)->vtable->domain;
788 #include "sgen-scan-object.h"
791 static gboolean scan_object_for_specific_ref_precise = TRUE;
794 #define HANDLE_PTR(ptr,obj) do { \
795 if ((MonoObject*)*(ptr) == key) { \
796 g_print ("found ref to %p in object %p (%s) at offset %td\n", \
797 key, (obj), safe_name ((obj)), ((char*)(ptr) - (char*)(obj))); \
802 scan_object_for_specific_ref (char *start, MonoObject *key)
806 if ((forwarded = SGEN_OBJECT_IS_FORWARDED (start)))
809 if (scan_object_for_specific_ref_precise) {
810 #include "sgen-scan-object.h"
812 mword *words = (mword*)start;
813 size_t size = safe_object_get_size ((MonoObject*)start);
815 for (i = 0; i < size / sizeof (mword); ++i) {
816 if (words [i] == (mword)key) {
817 g_print ("found possible ref to %p in object %p (%s) at offset %td\n",
818 key, start, safe_name (start), i * sizeof (mword));
825 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
827 while (start < end) {
831 if (!*(void**)start) {
832 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
837 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
843 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
845 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
846 callback (obj, size, data);
853 scan_object_for_specific_ref_callback (char *obj, size_t size, MonoObject *key)
855 scan_object_for_specific_ref (obj, key);
859 check_root_obj_specific_ref (RootRecord *root, MonoObject *key, MonoObject *obj)
863 g_print ("found ref to %p in root record %p\n", key, root);
866 static MonoObject *check_key = NULL;
867 static RootRecord *check_root = NULL;
870 check_root_obj_specific_ref_from_marker (void **obj)
872 check_root_obj_specific_ref (check_root, check_key, *obj);
876 scan_roots_for_specific_ref (MonoObject *key, int root_type)
882 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
883 mword desc = root->root_desc;
887 switch (desc & ROOT_DESC_TYPE_MASK) {
888 case ROOT_DESC_BITMAP:
889 desc >>= ROOT_DESC_TYPE_SHIFT;
892 check_root_obj_specific_ref (root, key, *start_root);
897 case ROOT_DESC_COMPLEX: {
898 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
899 int bwords = (*bitmap_data) - 1;
900 void **start_run = start_root;
902 while (bwords-- > 0) {
903 gsize bmap = *bitmap_data++;
904 void **objptr = start_run;
907 check_root_obj_specific_ref (root, key, *objptr);
911 start_run += GC_BITS_PER_WORD;
915 case ROOT_DESC_USER: {
916 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
917 marker (start_root, check_root_obj_specific_ref_from_marker);
920 case ROOT_DESC_RUN_LEN:
921 g_assert_not_reached ();
923 g_assert_not_reached ();
925 } SGEN_HASH_TABLE_FOREACH_END;
932 mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise)
937 scan_object_for_specific_ref_precise = precise;
939 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
940 (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key, TRUE);
942 major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
944 sgen_los_iterate_objects ((IterateObjectCallbackFunc)scan_object_for_specific_ref_callback, key);
946 scan_roots_for_specific_ref (key, ROOT_TYPE_NORMAL);
947 scan_roots_for_specific_ref (key, ROOT_TYPE_WBARRIER);
949 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], ptr, root) {
950 while (ptr < (void**)root->end_root) {
951 check_root_obj_specific_ref (root, *ptr, key);
954 } SGEN_HASH_TABLE_FOREACH_END;
958 need_remove_object_for_domain (char *start, MonoDomain *domain)
960 if (mono_object_domain (start) == domain) {
961 DEBUG (4, fprintf (gc_debug_file, "Need to cleanup object %p\n", start));
962 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
969 process_object_for_domain_clearing (char *start, MonoDomain *domain)
971 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
972 if (vt->klass == mono_defaults.internal_thread_class)
973 g_assert (mono_object_domain (start) == mono_get_root_domain ());
974 /* The object could be a proxy for an object in the domain
976 if (mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
977 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
979 /* The server could already have been zeroed out, so
980 we need to check for that, too. */
981 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
982 DEBUG (4, fprintf (gc_debug_file, "Cleaning up remote pointer in %p to object %p\n",
984 ((MonoRealProxy*)start)->unwrapped_server = NULL;
989 static MonoDomain *check_domain = NULL;
992 check_obj_not_in_domain (void **o)
994 g_assert (((MonoObject*)(*o))->vtable->domain != check_domain);
998 scan_for_registered_roots_in_domain (MonoDomain *domain, int root_type)
1002 check_domain = domain;
1003 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1004 mword desc = root->root_desc;
1006 /* The MonoDomain struct is allowed to hold
1007 references to objects in its own domain. */
1008 if (start_root == (void**)domain)
1011 switch (desc & ROOT_DESC_TYPE_MASK) {
1012 case ROOT_DESC_BITMAP:
1013 desc >>= ROOT_DESC_TYPE_SHIFT;
1015 if ((desc & 1) && *start_root)
1016 check_obj_not_in_domain (*start_root);
1021 case ROOT_DESC_COMPLEX: {
1022 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1023 int bwords = (*bitmap_data) - 1;
1024 void **start_run = start_root;
1026 while (bwords-- > 0) {
1027 gsize bmap = *bitmap_data++;
1028 void **objptr = start_run;
1030 if ((bmap & 1) && *objptr)
1031 check_obj_not_in_domain (*objptr);
1035 start_run += GC_BITS_PER_WORD;
1039 case ROOT_DESC_USER: {
1040 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1041 marker (start_root, check_obj_not_in_domain);
1044 case ROOT_DESC_RUN_LEN:
1045 g_assert_not_reached ();
1047 g_assert_not_reached ();
1049 } SGEN_HASH_TABLE_FOREACH_END;
1051 check_domain = NULL;
1055 check_for_xdomain_refs (void)
1059 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1060 (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL, FALSE);
1062 major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)scan_object_for_xdomain_refs, NULL);
1064 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1065 scan_object_for_xdomain_refs (bigobj->data, bigobj->size, NULL);
1069 clear_domain_process_object (char *obj, MonoDomain *domain)
1073 process_object_for_domain_clearing (obj, domain);
1074 remove = need_remove_object_for_domain (obj, domain);
1076 if (remove && ((MonoObject*)obj)->synchronisation) {
1077 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
1079 mono_gc_register_disappearing_link (NULL, dislink, FALSE, TRUE);
1086 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
1088 if (clear_domain_process_object (obj, domain))
1089 memset (obj, 0, size);
1093 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
1095 clear_domain_process_object (obj, domain);
1099 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1101 if (need_remove_object_for_domain (obj, domain))
1102 major_collector.free_non_pinned_object (obj, size);
1106 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
1108 if (need_remove_object_for_domain (obj, domain))
1109 major_collector.free_pinned_object (obj, size);
1113 * When appdomains are unloaded we can easily remove objects that have finalizers,
1114 * but all the others could still be present in random places on the heap.
1115 * We need a sweep to get rid of them even though it's going to be costly
1117 * The reason we need to remove them is because we access the vtable and class
1118 * structures to know the object size and the reference bitmap: once the domain is
1119 * unloaded the point to random memory.
1122 mono_gc_clear_domain (MonoDomain * domain)
1124 LOSObject *bigobj, *prev;
1129 process_fin_stage_entries ();
1130 process_dislink_stage_entries ();
1132 sgen_clear_nursery_fragments ();
1134 if (xdomain_checks && domain != mono_get_root_domain ()) {
1135 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
1136 scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
1137 check_for_xdomain_refs ();
1140 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
1141 to memory returned to the OS.*/
1142 null_ephemerons_for_domain (domain);
1144 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1145 null_links_for_domain (domain, i);
1147 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
1148 remove_finalizers_for_domain (domain, i);
1150 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1151 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
1153 /* We need two passes over major and large objects because
1154 freeing such objects might give their memory back to the OS
1155 (in the case of large objects) or obliterate its vtable
1156 (pinned objects with major-copying or pinned and non-pinned
1157 objects with major-mark&sweep), but we might need to
1158 dereference a pointer from an object to another object if
1159 the first object is a proxy. */
1160 major_collector.iterate_objects (TRUE, TRUE, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
1161 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1162 clear_domain_process_object (bigobj->data, domain);
1165 for (bigobj = los_object_list; bigobj;) {
1166 if (need_remove_object_for_domain (bigobj->data, domain)) {
1167 LOSObject *to_free = bigobj;
1169 prev->next = bigobj->next;
1171 los_object_list = bigobj->next;
1172 bigobj = bigobj->next;
1173 DEBUG (4, fprintf (gc_debug_file, "Freeing large object %p\n",
1175 sgen_los_free_object (to_free);
1179 bigobj = bigobj->next;
1181 major_collector.iterate_objects (TRUE, FALSE, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
1182 major_collector.iterate_objects (FALSE, TRUE, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
1184 if (G_UNLIKELY (do_pin_stats)) {
1185 if (domain == mono_get_root_domain ())
1186 sgen_pin_stats_print_class_stats ();
1193 * sgen_add_to_global_remset:
1195 * The global remset contains locations which point into newspace after
1196 * a minor collection. This can happen if the objects they point to are pinned.
1198 * LOCKING: If called from a parallel collector, the global remset
1199 * lock must be held. For serial collectors that is not necessary.
1202 sgen_add_to_global_remset (gpointer ptr)
1204 remset.record_pointer (ptr);
1208 * sgen_drain_gray_stack:
1210 * Scan objects in the gray stack until the stack is empty. This should be called
1211 * frequently after each object is copied, to achieve better locality and cache
1215 sgen_drain_gray_stack (GrayQueue *queue, int max_objs)
1218 ScanObjectFunc scan_func = current_object_ops.scan_object;
1220 if (max_objs == -1) {
1222 GRAY_OBJECT_DEQUEUE (queue, obj);
1225 DEBUG (9, fprintf (gc_debug_file, "Precise gray object scan %p (%s)\n", obj, safe_name (obj)));
1226 scan_func (obj, queue);
1232 for (i = 0; i != max_objs; ++i) {
1233 GRAY_OBJECT_DEQUEUE (queue, obj);
1236 DEBUG (9, fprintf (gc_debug_file, "Precise gray object scan %p (%s)\n", obj, safe_name (obj)));
1237 scan_func (obj, queue);
1239 } while (max_objs < 0);
1245 * Addresses from start to end are already sorted. This function finds
1246 * the object header for each address and pins the object. The
1247 * addresses must be inside the passed section. The (start of the)
1248 * address array is overwritten with the addresses of the actually
1249 * pinned objects. Return the number of pinned objects.
1252 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, GrayQueue *queue)
1257 void *last_obj = NULL;
1258 size_t last_obj_size = 0;
1261 void **definitely_pinned = start;
1263 sgen_nursery_allocator_prepare_for_pinning ();
1265 while (start < end) {
1267 /* the range check should be reduntant */
1268 if (addr != last && addr >= start_nursery && addr < end_nursery) {
1269 DEBUG (5, fprintf (gc_debug_file, "Considering pinning addr %p\n", addr));
1270 /* multiple pointers to the same object */
1271 if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
1275 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
1276 g_assert (idx < section->num_scan_start);
1277 search_start = (void*)section->scan_starts [idx];
1278 if (!search_start || search_start > addr) {
1281 search_start = section->scan_starts [idx];
1282 if (search_start && search_start <= addr)
1285 if (!search_start || search_start > addr)
1286 search_start = start_nursery;
1288 if (search_start < last_obj)
1289 search_start = (char*)last_obj + last_obj_size;
1290 /* now addr should be in an object a short distance from search_start
1291 * Note that search_start must point to zeroed mem or point to an object.
1295 if (!*(void**)search_start) {
1296 /* Consistency check */
1298 for (frag = nursery_fragments; frag; frag = frag->next) {
1299 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
1300 g_assert_not_reached ();
1304 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
1307 last_obj = search_start;
1308 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1310 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
1311 /* Marks the beginning of a nursery fragment, skip */
1313 DEBUG (8, fprintf (gc_debug_file, "Pinned try match %p (%s), size %zd\n", last_obj, safe_name (last_obj), last_obj_size));
1314 if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
1315 DEBUG (4, fprintf (gc_debug_file, "Pinned object %p, vtable %p (%s), count %d\n", search_start, *(void**)search_start, safe_name (search_start), count));
1316 binary_protocol_pin (search_start, (gpointer)LOAD_VTABLE (search_start), safe_object_get_size (search_start));
1317 pin_object (search_start);
1318 GRAY_OBJECT_ENQUEUE (queue, search_start);
1319 if (G_UNLIKELY (do_pin_stats))
1320 sgen_pin_stats_register_object (search_start, last_obj_size);
1321 definitely_pinned [count] = search_start;
1326 /* skip to the next object */
1327 search_start = (void*)((char*)search_start + last_obj_size);
1328 } while (search_start <= addr);
1329 /* we either pinned the correct object or we ignored the addr because
1330 * it points to unused zeroed memory.
1336 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1337 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1338 GCRootReport report;
1340 for (idx = 0; idx < count; ++idx)
1341 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1342 notify_gc_roots (&report);
1344 stat_pinned_objects += count;
1349 sgen_pin_objects_in_section (GCMemSection *section, GrayQueue *queue)
1351 int num_entries = section->pin_queue_num_entries;
1353 void **start = section->pin_queue_start;
1355 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1356 section->data, section->next_data, queue);
1357 section->pin_queue_num_entries = reduced_to;
1359 section->pin_queue_start = NULL;
1365 sgen_pin_object (void *object, GrayQueue *queue)
1367 if (sgen_collection_is_parallel ()) {
1369 /*object arrives pinned*/
1370 sgen_pin_stage_ptr (object);
1374 SGEN_PIN_OBJECT (object);
1375 sgen_pin_stage_ptr (object);
1377 if (G_UNLIKELY (do_pin_stats))
1378 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1380 GRAY_OBJECT_ENQUEUE (queue, object);
1381 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1385 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1389 gboolean major_pinned = FALSE;
1391 if (sgen_ptr_in_nursery (obj)) {
1392 if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1393 sgen_pin_object (obj, queue);
1397 major_collector.pin_major_object (obj, queue);
1398 major_pinned = TRUE;
1401 vtable_word = *(mword*)obj;
1402 /*someone else forwarded it, update the pointer and bail out*/
1403 if (vtable_word & SGEN_FORWARDED_BIT) {
1404 *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1408 /*someone pinned it, nothing to do.*/
1409 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1414 /* Sort the addresses in array in increasing order.
1415 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1418 sgen_sort_addresses (void **array, int size)
1423 for (i = 1; i < size; ++i) {
1426 int parent = (child - 1) / 2;
1428 if (array [parent] >= array [child])
1431 tmp = array [parent];
1432 array [parent] = array [child];
1433 array [child] = tmp;
1439 for (i = size - 1; i > 0; --i) {
1442 array [i] = array [0];
1448 while (root * 2 + 1 <= end) {
1449 int child = root * 2 + 1;
1451 if (child < end && array [child] < array [child + 1])
1453 if (array [root] >= array [child])
1457 array [root] = array [child];
1458 array [child] = tmp;
1466 * Scan the memory between start and end and queue values which could be pointers
1467 * to the area between start_nursery and end_nursery for later consideration.
1468 * Typically used for thread stacks.
1471 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1474 while (start < end) {
1475 if (*start >= start_nursery && *start < end_nursery) {
1477 * *start can point to the middle of an object
1478 * note: should we handle pointing at the end of an object?
1479 * pinning in C# code disallows pointing at the end of an object
1480 * but there is some small chance that an optimizing C compiler
1481 * may keep the only reference to an object by pointing
1482 * at the end of it. We ignore this small chance for now.
1483 * Pointers to the end of an object are indistinguishable
1484 * from pointers to the start of the next object in memory
1485 * so if we allow that we'd need to pin two objects...
1486 * We queue the pointer in an array, the
1487 * array will then be sorted and uniqued. This way
1488 * we can coalesce several pinning pointers and it should
1489 * be faster since we'd do a memory scan with increasing
1490 * addresses. Note: we can align the address to the allocation
1491 * alignment, so the unique process is more effective.
1493 mword addr = (mword)*start;
1494 addr &= ~(ALLOC_ALIGN - 1);
1495 if (addr >= (mword)start_nursery && addr < (mword)end_nursery)
1496 sgen_pin_stage_ptr ((void*)addr);
1497 if (G_UNLIKELY (do_pin_stats)) {
1498 if (ptr_in_nursery ((void*)addr))
1499 sgen_pin_stats_register_address ((char*)addr, pin_type);
1501 DEBUG (6, if (count) fprintf (gc_debug_file, "Pinning address %p from %p\n", (void*)addr, start));
1506 DEBUG (7, if (count) fprintf (gc_debug_file, "found %d potential pinned heap pointers\n", count));
1510 * Debugging function: find in the conservative roots where @obj is being pinned.
1512 static G_GNUC_UNUSED void
1513 find_pinning_reference (char *obj, size_t size)
1517 char *endobj = obj + size;
1519 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_NORMAL], start, root) {
1520 /* if desc is non-null it has precise info */
1521 if (!root->root_desc) {
1522 while (start < (char**)root->end_root) {
1523 if (*start >= obj && *start < endobj) {
1524 DEBUG (0, fprintf (gc_debug_file, "Object %p referenced in pinned roots %p-%p\n", obj, start, root->end_root));
1529 } SGEN_HASH_TABLE_FOREACH_END;
1531 find_pinning_ref_from_thread (obj, size);
1535 * The first thing we do in a collection is to identify pinned objects.
1536 * This function considers all the areas of memory that need to be
1537 * conservatively scanned.
1540 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1544 DEBUG (2, fprintf (gc_debug_file, "Scanning pinned roots (%d bytes, %d/%d entries)\n", (int)roots_size, roots_hash [ROOT_TYPE_NORMAL].num_entries, roots_hash [ROOT_TYPE_PINNED].num_entries));
1545 /* objects pinned from the API are inside these roots */
1546 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1547 DEBUG (6, fprintf (gc_debug_file, "Pinned roots %p-%p\n", start_root, root->end_root));
1548 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1549 } SGEN_HASH_TABLE_FOREACH_END;
1550 /* now deal with the thread stacks
1551 * in the future we should be able to conservatively scan only:
1552 * *) the cpu registers
1553 * *) the unmanaged stack frames
1554 * *) the _last_ managed stack frame
1555 * *) pointers slots in managed frames
1557 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1561 CopyOrMarkObjectFunc func;
1563 } UserCopyOrMarkData;
1565 static MonoNativeTlsKey user_copy_or_mark_key;
1568 init_user_copy_or_mark_key (void)
1570 mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1574 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1576 mono_native_tls_set_value (user_copy_or_mark_key, data);
1580 single_arg_user_copy_or_mark (void **obj)
1582 UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1584 data->func (obj, data->queue);
1588 * The memory area from start_root to end_root contains pointers to objects.
1589 * Their position is precisely described by @desc (this means that the pointer
1590 * can be either NULL or the pointer to the start of an object).
1591 * This functions copies them to to_space updates them.
1593 * This function is not thread-safe!
1596 precisely_scan_objects_from (CopyOrMarkObjectFunc copy_func, void** start_root, void** end_root, char* n_start, char *n_end, mword desc, GrayQueue *queue)
1598 switch (desc & ROOT_DESC_TYPE_MASK) {
1599 case ROOT_DESC_BITMAP:
1600 desc >>= ROOT_DESC_TYPE_SHIFT;
1602 if ((desc & 1) && *start_root) {
1603 copy_func (start_root, queue);
1604 DEBUG (9, fprintf (gc_debug_file, "Overwrote root at %p with %p\n", start_root, *start_root));
1605 sgen_drain_gray_stack (queue, -1);
1611 case ROOT_DESC_COMPLEX: {
1612 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1613 int bwords = (*bitmap_data) - 1;
1614 void **start_run = start_root;
1616 while (bwords-- > 0) {
1617 gsize bmap = *bitmap_data++;
1618 void **objptr = start_run;
1620 if ((bmap & 1) && *objptr) {
1621 copy_func (objptr, queue);
1622 DEBUG (9, fprintf (gc_debug_file, "Overwrote root at %p with %p\n", objptr, *objptr));
1623 sgen_drain_gray_stack (queue, -1);
1628 start_run += GC_BITS_PER_WORD;
1632 case ROOT_DESC_USER: {
1633 UserCopyOrMarkData data = { copy_func, queue };
1634 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1635 set_user_copy_or_mark_data (&data);
1636 marker (start_root, single_arg_user_copy_or_mark);
1637 set_user_copy_or_mark_data (NULL);
1640 case ROOT_DESC_RUN_LEN:
1641 g_assert_not_reached ();
1643 g_assert_not_reached ();
1648 reset_heap_boundaries (void)
1650 lowest_heap_address = ~(mword)0;
1651 highest_heap_address = 0;
1655 sgen_update_heap_boundaries (mword low, mword high)
1660 old = lowest_heap_address;
1663 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1666 old = highest_heap_address;
1669 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1672 static unsigned long
1673 prot_flags_for_activate (int activate)
1675 unsigned long prot_flags = activate? MONO_MMAP_READ|MONO_MMAP_WRITE: MONO_MMAP_NONE;
1676 return prot_flags | MONO_MMAP_PRIVATE | MONO_MMAP_ANON;
1680 * Allocate a big chunk of memory from the OS (usually 64KB to several megabytes).
1681 * This must not require any lock.
1684 sgen_alloc_os_memory (size_t size, int activate)
1686 void *ptr = mono_valloc (0, size, prot_flags_for_activate (activate));
1689 total_alloc += size;
1694 /* size must be a power of 2 */
1696 sgen_alloc_os_memory_aligned (mword size, mword alignment, gboolean activate)
1698 void *ptr = mono_valloc_aligned (size, alignment, prot_flags_for_activate (activate));
1701 total_alloc += size;
1707 * Free the memory returned by sgen_alloc_os_memory (), returning it to the OS.
1710 sgen_free_os_memory (void *addr, size_t size)
1712 mono_vfree (addr, size);
1714 total_alloc -= size;
1718 * Allocate and setup the data structures needed to be able to allocate objects
1719 * in the nursery. The nursery is stored in nursery_section.
1722 alloc_nursery (void)
1724 GCMemSection *section;
1729 if (nursery_section)
1731 DEBUG (2, fprintf (gc_debug_file, "Allocating nursery size: %lu\n", (unsigned long)sgen_nursery_size));
1732 /* later we will alloc a larger area for the nursery but only activate
1733 * what we need. The rest will be used as expansion if we have too many pinned
1734 * objects in the existing nursery.
1736 /* FIXME: handle OOM */
1737 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1739 alloc_size = sgen_nursery_size;
1740 #ifdef SGEN_ALIGN_NURSERY
1741 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1743 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1745 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1746 DEBUG (4, fprintf (gc_debug_file, "Expanding nursery size (%p-%p): %lu, total: %lu\n", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)total_alloc));
1747 section->data = section->next_data = data;
1748 section->size = alloc_size;
1749 section->end_data = data + sgen_nursery_size;
1750 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1751 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS);
1752 section->num_scan_start = scan_starts;
1753 section->block.role = MEMORY_ROLE_GEN0;
1754 section->block.next = NULL;
1756 nursery_section = section;
1758 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1762 mono_gc_get_nursery (int *shift_bits, size_t *size)
1764 *size = sgen_nursery_size;
1765 #ifdef SGEN_ALIGN_NURSERY
1766 *shift_bits = DEFAULT_NURSERY_BITS;
1770 return sgen_get_nursery_start ();
1774 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1776 SgenThreadInfo *info = mono_thread_info_current ();
1778 /* Could be called from sgen_thread_unregister () with a NULL info */
1781 info->stopped_domain = domain;
1786 mono_gc_precise_stack_mark_enabled (void)
1788 return !conservative_stack_mark;
1792 mono_gc_get_logfile (void)
1794 return sgen_get_logfile ();
1798 report_finalizer_roots_list (FinalizeReadyEntry *list)
1800 GCRootReport report;
1801 FinalizeReadyEntry *fin;
1804 for (fin = list; fin; fin = fin->next) {
1807 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1809 notify_gc_roots (&report);
1813 report_finalizer_roots (void)
1815 report_finalizer_roots_list (fin_ready_list);
1816 report_finalizer_roots_list (critical_fin_list);
1819 static GCRootReport *root_report;
1822 single_arg_report_root (void **obj)
1825 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1829 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1831 switch (desc & ROOT_DESC_TYPE_MASK) {
1832 case ROOT_DESC_BITMAP:
1833 desc >>= ROOT_DESC_TYPE_SHIFT;
1835 if ((desc & 1) && *start_root) {
1836 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1842 case ROOT_DESC_COMPLEX: {
1843 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1844 int bwords = (*bitmap_data) - 1;
1845 void **start_run = start_root;
1847 while (bwords-- > 0) {
1848 gsize bmap = *bitmap_data++;
1849 void **objptr = start_run;
1851 if ((bmap & 1) && *objptr) {
1852 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1857 start_run += GC_BITS_PER_WORD;
1861 case ROOT_DESC_USER: {
1862 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1863 root_report = report;
1864 marker (start_root, single_arg_report_root);
1867 case ROOT_DESC_RUN_LEN:
1868 g_assert_not_reached ();
1870 g_assert_not_reached ();
1875 report_registered_roots_by_type (int root_type)
1877 GCRootReport report;
1881 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1882 DEBUG (6, fprintf (gc_debug_file, "Precise root scan %p-%p (desc: %p)\n", start_root, root->end_root, (void*)root->root_desc));
1883 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1884 } SGEN_HASH_TABLE_FOREACH_END;
1885 notify_gc_roots (&report);
1889 report_registered_roots (void)
1891 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1892 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1896 scan_finalizer_entries (CopyOrMarkObjectFunc copy_func, FinalizeReadyEntry *list, GrayQueue *queue)
1898 FinalizeReadyEntry *fin;
1900 for (fin = list; fin; fin = fin->next) {
1903 DEBUG (5, fprintf (gc_debug_file, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object)));
1904 copy_func (&fin->object, queue);
1909 generation_name (int generation)
1911 switch (generation) {
1912 case GENERATION_NURSERY: return "nursery";
1913 case GENERATION_OLD: return "old";
1914 default: g_assert_not_reached ();
1920 stw_bridge_process (void)
1922 sgen_bridge_processing_stw_step ();
1926 bridge_process (void)
1928 sgen_bridge_processing_finish ();
1931 SgenObjectOperations *
1932 sgen_get_current_object_ops (void){
1933 return ¤t_object_ops;
1938 finish_gray_stack (char *start_addr, char *end_addr, int generation, GrayQueue *queue)
1942 int done_with_ephemerons, ephemeron_rounds = 0;
1943 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1946 * We copied all the reachable objects. Now it's the time to copy
1947 * the objects that were not referenced by the roots, but by the copied objects.
1948 * we built a stack of objects pointed to by gray_start: they are
1949 * additional roots and we may add more items as we go.
1950 * We loop until gray_start == gray_objects which means no more objects have
1951 * been added. Note this is iterative: no recursion is involved.
1952 * We need to walk the LO list as well in search of marked big objects
1953 * (use a flag since this is needed only on major collections). We need to loop
1954 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1955 * To achieve better cache locality and cache usage, we drain the gray stack
1956 * frequently, after each object is copied, and just finish the work here.
1958 sgen_drain_gray_stack (queue, -1);
1960 DEBUG (2, fprintf (gc_debug_file, "%s generation done\n", generation_name (generation)));
1963 Reset bridge data, we might have lingering data from a previous collection if this is a major
1964 collection trigged by minor overflow.
1966 We must reset the gathered bridges since their original block might be evacuated due to major
1967 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1969 sgen_bridge_reset_data ();
1972 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1973 * before processing finalizable objects or non-tracking weak hamdle to avoid finalizing/clearing
1974 * objects that are in fact reachable.
1976 done_with_ephemerons = 0;
1978 done_with_ephemerons = mark_ephemerons_in_range (copy_func, start_addr, end_addr, queue);
1979 sgen_drain_gray_stack (queue, -1);
1981 } while (!done_with_ephemerons);
1983 sgen_scan_togglerefs (copy_func, start_addr, end_addr, queue);
1984 if (generation == GENERATION_OLD)
1985 sgen_scan_togglerefs (copy_func, sgen_get_nursery_start (), sgen_get_nursery_end (), queue);
1987 if (sgen_need_bridge_processing ()) {
1988 collect_bridge_objects (copy_func, start_addr, end_addr, generation, queue);
1989 if (generation == GENERATION_OLD)
1990 collect_bridge_objects (copy_func, sgen_get_nursery_start (), sgen_get_nursery_end (), GENERATION_NURSERY, queue);
1994 Make sure we drain the gray stack before processing disappearing links and finalizers.
1995 If we don't make sure it is empty we might wrongly see a live object as dead.
1997 sgen_drain_gray_stack (queue, -1);
2000 We must clear weak links that don't track resurrection before processing object ready for
2001 finalization so they can be cleared before that.
2003 null_link_in_range (copy_func, start_addr, end_addr, generation, TRUE, queue);
2004 if (generation == GENERATION_OLD)
2005 null_link_in_range (copy_func, start_addr, end_addr, GENERATION_NURSERY, TRUE, queue);
2008 /* walk the finalization queue and move also the objects that need to be
2009 * finalized: use the finalized objects as new roots so the objects they depend
2010 * on are also not reclaimed. As with the roots above, only objects in the nursery
2011 * are marked/copied.
2013 finalize_in_range (copy_func, start_addr, end_addr, generation, queue);
2014 if (generation == GENERATION_OLD)
2015 finalize_in_range (copy_func, sgen_get_nursery_start (), sgen_get_nursery_end (), GENERATION_NURSERY, queue);
2016 /* drain the new stack that might have been created */
2017 DEBUG (6, fprintf (gc_debug_file, "Precise scan of gray area post fin\n"));
2018 sgen_drain_gray_stack (queue, -1);
2021 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
2023 done_with_ephemerons = 0;
2025 done_with_ephemerons = mark_ephemerons_in_range (copy_func, start_addr, end_addr, queue);
2026 sgen_drain_gray_stack (queue, -1);
2028 } while (!done_with_ephemerons);
2031 * Clear ephemeron pairs with unreachable keys.
2032 * We pass the copy func so we can figure out if an array was promoted or not.
2034 clear_unreachable_ephemerons (copy_func, start_addr, end_addr, queue);
2037 DEBUG (2, fprintf (gc_debug_file, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron roundss\n", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds));
2040 * handle disappearing links
2041 * Note we do this after checking the finalization queue because if an object
2042 * survives (at least long enough to be finalized) we don't clear the link.
2043 * This also deals with a possible issue with the monitor reclamation: with the Boehm
2044 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
2047 g_assert (sgen_gray_object_queue_is_empty (queue));
2049 null_link_in_range (copy_func, start_addr, end_addr, generation, FALSE, queue);
2050 if (generation == GENERATION_OLD)
2051 null_link_in_range (copy_func, start_addr, end_addr, GENERATION_NURSERY, FALSE, queue);
2052 if (sgen_gray_object_queue_is_empty (queue))
2054 sgen_drain_gray_stack (queue, -1);
2057 g_assert (sgen_gray_object_queue_is_empty (queue));
2061 sgen_check_section_scan_starts (GCMemSection *section)
2064 for (i = 0; i < section->num_scan_start; ++i) {
2065 if (section->scan_starts [i]) {
2066 guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
2067 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
2073 check_scan_starts (void)
2075 if (!do_scan_starts_check)
2077 sgen_check_section_scan_starts (nursery_section);
2078 major_collector.check_scan_starts ();
2082 scan_from_registered_roots (CopyOrMarkObjectFunc copy_func, char *addr_start, char *addr_end, int root_type, GrayQueue *queue)
2086 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
2087 DEBUG (6, fprintf (gc_debug_file, "Precise root scan %p-%p (desc: %p)\n", start_root, root->end_root, (void*)root->root_desc));
2088 precisely_scan_objects_from (copy_func, start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, queue);
2089 } SGEN_HASH_TABLE_FOREACH_END;
2093 sgen_dump_occupied (char *start, char *end, char *section_start)
2095 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
2099 sgen_dump_section (GCMemSection *section, const char *type)
2101 char *start = section->data;
2102 char *end = section->data + section->size;
2103 char *occ_start = NULL;
2105 char *old_start = NULL; /* just for debugging */
2107 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
2109 while (start < end) {
2113 if (!*(void**)start) {
2115 sgen_dump_occupied (occ_start, start, section->data);
2118 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
2121 g_assert (start < section->next_data);
2126 vt = (GCVTable*)LOAD_VTABLE (start);
2129 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
2132 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
2133 start - section->data,
2134 vt->klass->name_space, vt->klass->name,
2142 sgen_dump_occupied (occ_start, start, section->data);
2144 fprintf (heap_dump_file, "</section>\n");
2148 dump_object (MonoObject *obj, gboolean dump_location)
2150 static char class_name [1024];
2152 MonoClass *class = mono_object_class (obj);
2156 * Python's XML parser is too stupid to parse angle brackets
2157 * in strings, so we just ignore them;
2160 while (class->name [i] && j < sizeof (class_name) - 1) {
2161 if (!strchr ("<>\"", class->name [i]))
2162 class_name [j++] = class->name [i];
2165 g_assert (j < sizeof (class_name));
2168 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
2169 class->name_space, class_name,
2170 safe_object_get_size (obj));
2171 if (dump_location) {
2172 const char *location;
2173 if (ptr_in_nursery (obj))
2174 location = "nursery";
2175 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
2179 fprintf (heap_dump_file, " location=\"%s\"", location);
2181 fprintf (heap_dump_file, "/>\n");
2185 dump_heap (const char *type, int num, const char *reason)
2190 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
2192 fprintf (heap_dump_file, " reason=\"%s\"", reason);
2193 fprintf (heap_dump_file, ">\n");
2194 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
2195 sgen_dump_internal_mem_usage (heap_dump_file);
2196 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
2197 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
2198 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
2200 fprintf (heap_dump_file, "<pinned-objects>\n");
2201 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
2202 dump_object (list->obj, TRUE);
2203 fprintf (heap_dump_file, "</pinned-objects>\n");
2205 sgen_dump_section (nursery_section, "nursery");
2207 major_collector.dump_heap (heap_dump_file);
2209 fprintf (heap_dump_file, "<los>\n");
2210 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
2211 dump_object ((MonoObject*)bigobj->data, FALSE);
2212 fprintf (heap_dump_file, "</los>\n");
2214 fprintf (heap_dump_file, "</collection>\n");
2218 sgen_register_moved_object (void *obj, void *destination)
2220 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
2222 /* FIXME: handle this for parallel collector */
2223 g_assert (!sgen_collection_is_parallel ());
2225 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
2226 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
2227 moved_objects_idx = 0;
2229 moved_objects [moved_objects_idx++] = obj;
2230 moved_objects [moved_objects_idx++] = destination;
2236 static gboolean inited = FALSE;
2241 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pre_collection_fragment_clear);
2242 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_pinning);
2243 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_remsets);
2244 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_pinned);
2245 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_registered_roots);
2246 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_scan_thread_data);
2247 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_finish_gray_stack);
2248 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_minor_fragment_creation);
2250 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pre_collection_fragment_clear);
2251 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_pinning);
2252 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_pinned);
2253 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_registered_roots);
2254 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_thread_data);
2255 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_alloc_pinned);
2256 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_finalized);
2257 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_scan_big_objects);
2258 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_finish_gray_stack);
2259 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_free_bigobjs);
2260 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_los_sweep);
2261 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_sweep);
2262 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_TIME_INTERVAL, &time_major_fragment_creation);
2264 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
2266 #ifdef HEAVY_STATISTICS
2267 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
2268 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
2269 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
2270 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
2271 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
2272 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
2273 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
2275 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
2276 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
2278 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
2279 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
2280 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
2281 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
2283 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
2284 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
2286 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
2288 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
2289 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
2290 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
2291 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
2293 sgen_nursery_allocator_init_heavy_stats ();
2294 sgen_alloc_init_heavy_stats ();
2300 static gboolean need_calculate_minor_collection_allowance;
2302 static int last_collection_old_num_major_sections;
2303 static mword last_collection_los_memory_usage = 0;
2304 static mword last_collection_old_los_memory_usage;
2305 static mword last_collection_los_memory_alloced;
2308 reset_minor_collection_allowance (void)
2310 need_calculate_minor_collection_allowance = TRUE;
2314 try_calculate_minor_collection_allowance (gboolean overwrite)
2316 int num_major_sections, num_major_sections_saved, save_target, allowance_target;
2317 mword los_memory_saved, new_major, new_heap_size;
2320 g_assert (need_calculate_minor_collection_allowance);
2322 if (!need_calculate_minor_collection_allowance)
2325 if (!*major_collector.have_swept) {
2327 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
2331 num_major_sections = major_collector.get_num_major_sections ();
2333 num_major_sections_saved = MAX (last_collection_old_num_major_sections - num_major_sections, 0);
2334 los_memory_saved = MAX (last_collection_old_los_memory_usage - last_collection_los_memory_usage, 1);
2336 new_major = num_major_sections * major_collector.section_size;
2337 new_heap_size = new_major + last_collection_los_memory_usage;
2340 * FIXME: Why is save_target half the major memory plus half the
2341 * LOS memory saved? Shouldn't it be half the major memory
2342 * saved plus half the LOS memory saved? Or half the whole heap
2345 save_target = (new_major + los_memory_saved) / 2;
2348 * We aim to allow the allocation of as many sections as is
2349 * necessary to reclaim save_target sections in the next
2350 * collection. We assume the collection pattern won't change.
2351 * In the last cycle, we had num_major_sections_saved for
2352 * minor_collection_sections_alloced. Assuming things won't
2353 * change, this must be the same ratio as save_target for
2354 * allowance_target, i.e.
2356 * num_major_sections_saved save_target
2357 * --------------------------------- == ----------------
2358 * minor_collection_sections_alloced allowance_target
2362 allowance_target = (mword)((double)save_target * (double)(minor_collection_sections_alloced * major_collector.section_size + last_collection_los_memory_alloced) / (double)(num_major_sections_saved * major_collector.section_size + los_memory_saved));
2364 minor_collection_allowance = MAX (MIN (allowance_target, num_major_sections * major_collector.section_size + los_memory_usage), MIN_MINOR_COLLECTION_ALLOWANCE);
2366 if (new_heap_size + minor_collection_allowance > soft_heap_limit) {
2367 if (new_heap_size > soft_heap_limit)
2368 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
2370 minor_collection_allowance = MAX (soft_heap_limit - new_heap_size, MIN_MINOR_COLLECTION_ALLOWANCE);
2373 if (debug_print_allowance) {
2374 mword old_major = last_collection_old_num_major_sections * major_collector.section_size;
2376 fprintf (gc_debug_file, "Before collection: %td bytes (%td major, %td LOS)\n",
2377 old_major + last_collection_old_los_memory_usage, old_major, last_collection_old_los_memory_usage);
2378 fprintf (gc_debug_file, "After collection: %td bytes (%td major, %td LOS)\n",
2379 new_heap_size, new_major, last_collection_los_memory_usage);
2380 fprintf (gc_debug_file, "Allowance: %td bytes\n", minor_collection_allowance);
2383 if (major_collector.have_computed_minor_collection_allowance)
2384 major_collector.have_computed_minor_collection_allowance ();
2386 need_calculate_minor_collection_allowance = FALSE;
2390 need_major_collection (mword space_needed)
2392 mword los_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
2393 return (space_needed > available_free_space ()) ||
2394 minor_collection_sections_alloced * major_collector.section_size + los_alloced > minor_collection_allowance;
2398 sgen_need_major_collection (mword space_needed)
2400 return need_major_collection (space_needed);
2404 reset_pinned_from_failed_allocation (void)
2406 bytes_pinned_from_failed_allocation = 0;
2410 sgen_set_pinned_from_failed_allocation (mword objsize)
2412 bytes_pinned_from_failed_allocation += objsize;
2416 sgen_collection_is_parallel (void)
2418 switch (current_collection_generation) {
2419 case GENERATION_NURSERY:
2420 return nursery_collection_is_parallel;
2421 case GENERATION_OLD:
2422 return major_collector.is_parallel;
2424 g_assert_not_reached ();
2432 } FinishRememberedSetScanJobData;
2435 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2437 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2439 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2444 CopyOrMarkObjectFunc func;
2448 } ScanFromRegisteredRootsJobData;
2451 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2453 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2455 scan_from_registered_roots (job_data->func,
2456 job_data->heap_start, job_data->heap_end,
2457 job_data->root_type,
2458 sgen_workers_get_job_gray_queue (worker_data));
2465 } ScanThreadDataJobData;
2468 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2470 ScanThreadDataJobData *job_data = job_data_untyped;
2472 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2473 sgen_workers_get_job_gray_queue (worker_data));
2478 FinalizeReadyEntry *list;
2479 } ScanFinalizerEntriesJobData;
2482 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2484 ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2486 scan_finalizer_entries (current_object_ops.copy_or_mark_object,
2488 sgen_workers_get_job_gray_queue (worker_data));
2492 verify_scan_starts (char *start, char *end)
2496 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2497 char *addr = nursery_section->scan_starts [i];
2498 if (addr > start && addr < end)
2499 fprintf (gc_debug_file, "NFC-BAD SCAN START [%d] %p for obj [%p %p]\n", i, addr, start, end);
2504 verify_nursery (void)
2506 char *start, *end, *cur, *hole_start;
2508 if (!do_verify_nursery)
2511 /*This cleans up unused fragments */
2512 sgen_nursery_allocator_prepare_for_pinning ();
2514 hole_start = start = cur = sgen_get_nursery_start ();
2515 end = sgen_get_nursery_end ();
2520 if (!*(void**)cur) {
2521 cur += sizeof (void*);
2525 if (object_is_forwarded (cur))
2526 fprintf (gc_debug_file, "FORWARDED OBJ %p\n", cur);
2527 else if (object_is_pinned (cur))
2528 fprintf (gc_debug_file, "PINNED OBJ %p\n", cur);
2530 ss = safe_object_get_size ((MonoObject*)cur);
2531 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2532 verify_scan_starts (cur, cur + size);
2533 if (do_dump_nursery_content) {
2534 if (cur > hole_start)
2535 fprintf (gc_debug_file, "HOLE [%p %p %d]\n", hole_start, cur, (int)(cur - hole_start));
2536 fprintf (gc_debug_file, "OBJ [%p %p %d %d %s %d]\n", cur, cur + size, (int)size, (int)ss, sgen_safe_name ((MonoObject*)cur), (gpointer)LOAD_VTABLE (cur) == sgen_get_array_fill_vtable ());
2541 fflush (gc_debug_file);
2545 * Collect objects in the nursery. Returns whether to trigger a major
2549 collect_nursery (size_t requested_size)
2551 gboolean needs_major;
2552 size_t max_garbage_amount;
2554 FinishRememberedSetScanJobData frssjd;
2555 ScanFromRegisteredRootsJobData scrrjd_normal, scrrjd_wbarrier;
2556 ScanFinalizerEntriesJobData sfejd_fin_ready, sfejd_critical_fin;
2557 ScanThreadDataJobData stdjd;
2558 mword fragment_total;
2559 TV_DECLARE (all_atv);
2560 TV_DECLARE (all_btv);
2564 if (disable_minor_collections)
2569 mono_perfcounters->gc_collections0++;
2571 current_collection_generation = GENERATION_NURSERY;
2572 if (sgen_collection_is_parallel ())
2573 current_object_ops = sgen_minor_collector.parallel_ops;
2575 current_object_ops = sgen_minor_collector.serial_ops;
2577 reset_pinned_from_failed_allocation ();
2579 binary_protocol_collection (GENERATION_NURSERY);
2580 check_scan_starts ();
2582 sgen_nursery_alloc_prepare_for_minor ();
2586 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2587 /* FIXME: optimize later to use the higher address where an object can be present */
2588 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2590 DEBUG (1, fprintf (gc_debug_file, "Start nursery collection %d %p-%p, size: %d\n", stat_minor_gcs, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ())));
2591 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2592 g_assert (nursery_section->size >= max_garbage_amount);
2594 /* world must be stopped already */
2595 TV_GETTIME (all_atv);
2599 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2602 check_for_xdomain_refs ();
2604 nursery_section->next_data = nursery_next;
2606 major_collector.start_nursery_collection ();
2608 try_calculate_minor_collection_allowance (FALSE);
2610 sgen_gray_object_queue_init (&gray_queue);
2611 sgen_workers_init_distribute_gray_queue ();
2614 mono_stats.minor_gc_count ++;
2616 if (remset.prepare_for_minor_collection)
2617 remset.prepare_for_minor_collection ();
2619 process_fin_stage_entries ();
2620 process_dislink_stage_entries ();
2622 /* pin from pinned handles */
2623 sgen_init_pinning ();
2624 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2625 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2626 /* identify pinned objects */
2627 sgen_optimize_pin_queue (0);
2628 sgen_pinning_setup_section (nursery_section);
2629 sgen_pin_objects_in_section (nursery_section, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2630 sgen_pinning_trim_queue_to_section (nursery_section);
2633 time_minor_pinning += TV_ELAPSED (btv, atv);
2634 DEBUG (2, fprintf (gc_debug_file, "Finding pinned pointers: %d in %d usecs\n", sgen_get_pinned_count (), TV_ELAPSED (btv, atv)));
2635 DEBUG (4, fprintf (gc_debug_file, "Start scan with %d pinned objects\n", sgen_get_pinned_count ()));
2637 if (whole_heap_check_before_collection)
2638 sgen_check_whole_heap_stw ();
2639 if (consistency_check_at_minor_collection)
2640 sgen_check_consistency ();
2642 sgen_workers_start_all_workers ();
2645 * Perform the sequential part of remembered set scanning.
2646 * This usually involves scanning global information that might later be produced by evacuation.
2648 if (remset.begin_scan_remsets)
2649 remset.begin_scan_remsets (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2651 sgen_workers_start_marking ();
2653 frssjd.heap_start = sgen_get_nursery_start ();
2654 frssjd.heap_end = nursery_next;
2655 sgen_workers_enqueue_job (job_finish_remembered_set_scan, &frssjd);
2657 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2659 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2660 DEBUG (2, fprintf (gc_debug_file, "Old generation scan: %d usecs\n", TV_ELAPSED (atv, btv)));
2662 if (!sgen_collection_is_parallel ())
2663 sgen_drain_gray_stack (&gray_queue, -1);
2665 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2666 report_registered_roots ();
2667 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2668 report_finalizer_roots ();
2670 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2672 /* registered roots, this includes static fields */
2673 scrrjd_normal.func = current_object_ops.copy_or_mark_object;
2674 scrrjd_normal.heap_start = sgen_get_nursery_start ();
2675 scrrjd_normal.heap_end = nursery_next;
2676 scrrjd_normal.root_type = ROOT_TYPE_NORMAL;
2677 sgen_workers_enqueue_job (job_scan_from_registered_roots, &scrrjd_normal);
2679 scrrjd_wbarrier.func = current_object_ops.copy_or_mark_object;
2680 scrrjd_wbarrier.heap_start = sgen_get_nursery_start ();
2681 scrrjd_wbarrier.heap_end = nursery_next;
2682 scrrjd_wbarrier.root_type = ROOT_TYPE_WBARRIER;
2683 sgen_workers_enqueue_job (job_scan_from_registered_roots, &scrrjd_wbarrier);
2686 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2689 stdjd.heap_start = sgen_get_nursery_start ();
2690 stdjd.heap_end = nursery_next;
2691 sgen_workers_enqueue_job (job_scan_thread_data, &stdjd);
2694 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2697 if (sgen_collection_is_parallel ()) {
2698 while (!sgen_gray_object_queue_is_empty (WORKERS_DISTRIBUTE_GRAY_QUEUE)) {
2699 sgen_workers_distribute_gray_queue_sections ();
2703 sgen_workers_join ();
2705 if (sgen_collection_is_parallel ())
2706 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2708 /* Scan the list of objects ready for finalization. If */
2709 sfejd_fin_ready.list = fin_ready_list;
2710 sgen_workers_enqueue_job (job_scan_finalizer_entries, &sfejd_fin_ready);
2712 sfejd_critical_fin.list = critical_fin_list;
2713 sgen_workers_enqueue_job (job_scan_finalizer_entries, &sfejd_critical_fin);
2715 finish_gray_stack (sgen_get_nursery_start (), nursery_next, GENERATION_NURSERY, &gray_queue);
2717 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2718 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2721 * The (single-threaded) finalization code might have done
2722 * some copying/marking so we can only reset the GC thread's
2723 * worker data here instead of earlier when we joined the
2726 sgen_workers_reset_data ();
2728 if (objects_pinned) {
2729 sgen_optimize_pin_queue (0);
2730 sgen_pinning_setup_section (nursery_section);
2733 /* walk the pin_queue, build up the fragment list of free memory, unmark
2734 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2737 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2738 fragment_total = sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries);
2739 if (!fragment_total)
2742 /* Clear TLABs for all threads */
2743 sgen_clear_tlabs ();
2745 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2747 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2748 DEBUG (2, fprintf (gc_debug_file, "Fragment creation: %d usecs, %lu bytes available\n", TV_ELAPSED (atv, btv), (unsigned long)fragment_total));
2750 if (consistency_check_at_minor_collection)
2751 sgen_check_major_refs ();
2753 major_collector.finish_nursery_collection ();
2755 TV_GETTIME (all_btv);
2756 mono_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2759 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2761 /* prepare the pin queue for the next collection */
2762 sgen_finish_pinning ();
2763 if (fin_ready_list || critical_fin_list) {
2764 DEBUG (4, fprintf (gc_debug_file, "Finalizer-thread wakeup: ready %d\n", num_ready_finalizers));
2765 mono_gc_finalize_notify ();
2767 sgen_pin_stats_reset ();
2769 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2771 if (remset.finish_minor_collection)
2772 remset.finish_minor_collection ();
2774 check_scan_starts ();
2776 binary_protocol_flush_buffers (FALSE);
2778 /*objects are late pinned because of lack of memory, so a major is a good call*/
2779 needs_major = need_major_collection (0) || objects_pinned;
2780 current_collection_generation = -1;
2787 sgen_collect_nursery_no_lock (size_t requested_size)
2789 gint64 gc_start_time;
2791 mono_profiler_gc_event (MONO_GC_EVENT_START, 0);
2792 gc_start_time = mono_100ns_ticks ();
2795 collect_nursery (requested_size);
2798 mono_trace_message (MONO_TRACE_GC, "minor gc took %d usecs", (mono_100ns_ticks () - gc_start_time) / 10);
2799 mono_profiler_gc_event (MONO_GC_EVENT_END, 0);
2803 major_do_collection (const char *reason)
2805 LOSObject *bigobj, *prevbo;
2806 TV_DECLARE (all_atv);
2807 TV_DECLARE (all_btv);
2810 /* FIXME: only use these values for the precise scan
2811 * note that to_space pointers should be excluded anyway...
2813 char *heap_start = NULL;
2814 char *heap_end = (char*)-1;
2815 int old_next_pin_slot;
2816 ScanFromRegisteredRootsJobData scrrjd_normal, scrrjd_wbarrier;
2817 ScanThreadDataJobData stdjd;
2818 ScanFinalizerEntriesJobData sfejd_fin_ready, sfejd_critical_fin;
2820 mono_perfcounters->gc_collections1++;
2822 current_object_ops = major_collector.major_ops;
2824 reset_pinned_from_failed_allocation ();
2826 last_collection_old_num_major_sections = major_collector.get_num_major_sections ();
2829 * A domain could have been freed, resulting in
2830 * los_memory_usage being less than last_collection_los_memory_usage.
2832 last_collection_los_memory_alloced = los_memory_usage - MIN (last_collection_los_memory_usage, los_memory_usage);
2833 last_collection_old_los_memory_usage = los_memory_usage;
2836 if (whole_heap_check_before_collection)
2837 sgen_check_whole_heap_stw ();
2839 //count_ref_nonref_objs ();
2840 //consistency_check ();
2842 binary_protocol_collection (GENERATION_OLD);
2843 check_scan_starts ();
2845 sgen_gray_object_queue_init (&gray_queue);
2846 sgen_workers_init_distribute_gray_queue ();
2847 sgen_nursery_alloc_prepare_for_major (reason);
2850 DEBUG (1, fprintf (gc_debug_file, "Start major collection %d\n", stat_major_gcs));
2852 mono_stats.major_gc_count ++;
2854 /* world must be stopped already */
2855 TV_GETTIME (all_atv);
2858 /* Pinning depends on this */
2859 sgen_clear_nursery_fragments ();
2862 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2864 nursery_section->next_data = sgen_get_nursery_end ();
2865 /* we should also coalesce scanning from sections close to each other
2866 * and deal with pointers outside of the sections later.
2869 if (major_collector.start_major_collection)
2870 major_collector.start_major_collection ();
2872 *major_collector.have_swept = FALSE;
2873 reset_minor_collection_allowance ();
2876 check_for_xdomain_refs ();
2878 /* Remsets are not useful for a major collection */
2879 remset.prepare_for_major_collection ();
2881 process_fin_stage_entries ();
2882 process_dislink_stage_entries ();
2885 sgen_init_pinning ();
2886 DEBUG (6, fprintf (gc_debug_file, "Collecting pinned addresses\n"));
2887 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2888 sgen_optimize_pin_queue (0);
2891 * pin_queue now contains all candidate pointers, sorted and
2892 * uniqued. We must do two passes now to figure out which
2893 * objects are pinned.
2895 * The first is to find within the pin_queue the area for each
2896 * section. This requires that the pin_queue be sorted. We
2897 * also process the LOS objects and pinned chunks here.
2899 * The second, destructive, pass is to reduce the section
2900 * areas to pointers to the actually pinned objects.
2902 DEBUG (6, fprintf (gc_debug_file, "Pinning from sections\n"));
2903 /* first pass for the sections */
2904 sgen_find_section_pin_queue_start_end (nursery_section);
2905 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2906 /* identify possible pointers to the insize of large objects */
2907 DEBUG (6, fprintf (gc_debug_file, "Pinning from large objects\n"));
2908 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2910 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2911 GCRootReport report;
2913 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + bigobj->size, &dummy)) {
2914 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
2915 pin_object (bigobj->data);
2916 /* FIXME: only enqueue if object has references */
2917 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data);
2918 if (G_UNLIKELY (do_pin_stats))
2919 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2920 DEBUG (6, fprintf (gc_debug_file, "Marked large object %p (%s) size: %lu from roots\n", bigobj->data, safe_name (bigobj->data), (unsigned long)bigobj->size));
2923 add_profile_gc_root (&report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2926 notify_gc_roots (&report);
2928 /* second pass for the sections */
2929 sgen_pin_objects_in_section (nursery_section, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2930 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2931 old_next_pin_slot = sgen_get_pinned_count ();
2934 time_major_pinning += TV_ELAPSED (atv, btv);
2935 DEBUG (2, fprintf (gc_debug_file, "Finding pinned pointers: %d in %d usecs\n", sgen_get_pinned_count (), TV_ELAPSED (atv, btv)));
2936 DEBUG (4, fprintf (gc_debug_file, "Start scan with %d pinned objects\n", sgen_get_pinned_count ()));
2938 major_collector.init_to_space ();
2940 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2941 main_gc_thread = mono_native_thread_self ();
2944 sgen_workers_start_all_workers ();
2945 sgen_workers_start_marking ();
2947 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2948 report_registered_roots ();
2950 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2952 /* registered roots, this includes static fields */
2953 scrrjd_normal.func = current_object_ops.copy_or_mark_object;
2954 scrrjd_normal.heap_start = heap_start;
2955 scrrjd_normal.heap_end = heap_end;
2956 scrrjd_normal.root_type = ROOT_TYPE_NORMAL;
2957 sgen_workers_enqueue_job (job_scan_from_registered_roots, &scrrjd_normal);
2959 scrrjd_wbarrier.func = current_object_ops.copy_or_mark_object;
2960 scrrjd_wbarrier.heap_start = heap_start;
2961 scrrjd_wbarrier.heap_end = heap_end;
2962 scrrjd_wbarrier.root_type = ROOT_TYPE_WBARRIER;
2963 sgen_workers_enqueue_job (job_scan_from_registered_roots, &scrrjd_wbarrier);
2966 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2969 stdjd.heap_start = heap_start;
2970 stdjd.heap_end = heap_end;
2971 sgen_workers_enqueue_job (job_scan_thread_data, &stdjd);
2974 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2977 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2979 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2980 report_finalizer_roots ();
2982 /* scan the list of objects ready for finalization */
2983 sfejd_fin_ready.list = fin_ready_list;
2984 sgen_workers_enqueue_job (job_scan_finalizer_entries, &sfejd_fin_ready);
2986 sfejd_critical_fin.list = critical_fin_list;
2987 sgen_workers_enqueue_job (job_scan_finalizer_entries, &sfejd_critical_fin);
2990 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2991 DEBUG (2, fprintf (gc_debug_file, "Root scan: %d usecs\n", TV_ELAPSED (btv, atv)));
2994 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2996 if (major_collector.is_parallel) {
2997 while (!sgen_gray_object_queue_is_empty (WORKERS_DISTRIBUTE_GRAY_QUEUE)) {
2998 sgen_workers_distribute_gray_queue_sections ();
3002 sgen_workers_join ();
3004 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
3005 main_gc_thread = NULL;
3008 if (major_collector.is_parallel)
3009 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3011 /* all the objects in the heap */
3012 finish_gray_stack (heap_start, heap_end, GENERATION_OLD, &gray_queue);
3014 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
3017 * The (single-threaded) finalization code might have done
3018 * some copying/marking so we can only reset the GC thread's
3019 * worker data here instead of earlier when we joined the
3022 sgen_workers_reset_data ();
3024 if (objects_pinned) {
3025 /*This is slow, but we just OOM'd*/
3026 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
3027 sgen_optimize_pin_queue (0);
3028 sgen_find_section_pin_queue_start_end (nursery_section);
3032 reset_heap_boundaries ();
3033 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
3035 /* sweep the big objects list */
3037 for (bigobj = los_object_list; bigobj;) {
3038 if (object_is_pinned (bigobj->data)) {
3039 unpin_object (bigobj->data);
3040 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + bigobj->size);
3043 /* not referenced anywhere, so we can free it */
3045 prevbo->next = bigobj->next;
3047 los_object_list = bigobj->next;
3049 bigobj = bigobj->next;
3050 sgen_los_free_object (to_free);
3054 bigobj = bigobj->next;
3058 time_major_free_bigobjs += TV_ELAPSED (atv, btv);
3063 time_major_los_sweep += TV_ELAPSED (btv, atv);
3065 major_collector.sweep ();
3068 time_major_sweep += TV_ELAPSED (atv, btv);
3070 /* walk the pin_queue, build up the fragment list of free memory, unmark
3071 * pinned objects as we go, memzero() the empty fragments so they are ready for the
3074 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries))
3077 /* Clear TLABs for all threads */
3078 sgen_clear_tlabs ();
3081 time_major_fragment_creation += TV_ELAPSED (btv, atv);
3083 TV_GETTIME (all_btv);
3084 mono_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3087 dump_heap ("major", stat_major_gcs - 1, reason);
3089 /* prepare the pin queue for the next collection */
3090 sgen_finish_pinning ();
3092 if (fin_ready_list || critical_fin_list) {
3093 DEBUG (4, fprintf (gc_debug_file, "Finalizer-thread wakeup: ready %d\n", num_ready_finalizers));
3094 mono_gc_finalize_notify ();
3096 sgen_pin_stats_reset ();
3098 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3100 try_calculate_minor_collection_allowance (TRUE);
3102 minor_collection_sections_alloced = 0;
3103 last_collection_los_memory_usage = los_memory_usage;
3105 major_collector.finish_major_collection ();
3107 check_scan_starts ();
3109 binary_protocol_flush_buffers (FALSE);
3111 //consistency_check ();
3113 return bytes_pinned_from_failed_allocation > 0;
3117 major_collection (const char *reason)
3119 gboolean need_minor_collection;
3121 if (disable_major_collections) {
3122 collect_nursery (0);
3126 major_collection_happened = TRUE;
3127 current_collection_generation = GENERATION_OLD;
3128 need_minor_collection = major_do_collection (reason);
3129 current_collection_generation = -1;
3131 if (need_minor_collection)
3132 collect_nursery (0);
3136 sgen_collect_major_no_lock (const char *reason)
3138 gint64 gc_start_time;
3140 mono_profiler_gc_event (MONO_GC_EVENT_START, 1);
3141 gc_start_time = mono_100ns_ticks ();
3143 major_collection (reason);
3145 mono_trace_message (MONO_TRACE_GC, "major gc took %d usecs", (mono_100ns_ticks () - gc_start_time) / 10);
3146 mono_profiler_gc_event (MONO_GC_EVENT_END, 1);
3150 * When deciding if it's better to collect or to expand, keep track
3151 * of how much garbage was reclaimed with the last collection: if it's too
3153 * This is called when we could not allocate a small object.
3155 static void __attribute__((noinline))
3156 minor_collect_or_expand_inner (size_t size)
3158 int do_minor_collection = 1;
3160 g_assert (nursery_section);
3161 if (do_minor_collection) {
3162 gint64 total_gc_time, major_gc_time = 0;
3164 mono_profiler_gc_event (MONO_GC_EVENT_START, 0);
3165 total_gc_time = mono_100ns_ticks ();
3168 if (collect_nursery (size)) {
3169 mono_profiler_gc_event (MONO_GC_EVENT_START, 1);
3170 major_gc_time = mono_100ns_ticks ();
3172 major_collection ("minor overflow");
3174 /* keep events symmetric */
3175 major_gc_time = mono_100ns_ticks () - major_gc_time;
3176 mono_profiler_gc_event (MONO_GC_EVENT_END, 1);
3178 DEBUG (2, fprintf (gc_debug_file, "Heap size: %lu, LOS size: %lu\n", (unsigned long)total_alloc, (unsigned long)los_memory_usage));
3181 total_gc_time = mono_100ns_ticks () - total_gc_time;
3183 mono_trace_message (MONO_TRACE_GC, "overflow major gc took %d usecs minor gc took %d usecs", total_gc_time / 10, (total_gc_time - major_gc_time) / 10);
3185 mono_trace_message (MONO_TRACE_GC, "minor gc took %d usecs", total_gc_time / 10);
3187 /* this also sets the proper pointers for the next allocation */
3188 if (!sgen_can_alloc_size (size)) {
3189 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3190 DEBUG (1, fprintf (gc_debug_file, "nursery collection didn't find enough room for %zd alloc (%d pinned)\n", size, sgen_get_pinned_count ()));
3191 sgen_dump_pin_queue ();
3194 mono_profiler_gc_event (MONO_GC_EVENT_END, 0);
3196 //report_internal_mem_usage ();
3200 sgen_minor_collect_or_expand_inner (size_t size)
3202 minor_collect_or_expand_inner (size);
3206 * ######################################################################
3207 * ######## Memory allocation from the OS
3208 * ######################################################################
3209 * This section of code deals with getting memory from the OS and
3210 * allocating memory for GC-internal data structures.
3211 * Internal memory can be handled with a freelist for small objects.
3217 G_GNUC_UNUSED static void
3218 report_internal_mem_usage (void)
3220 printf ("Internal memory usage:\n");
3221 sgen_report_internal_mem_usage ();
3222 printf ("Pinned memory usage:\n");
3223 major_collector.report_pinned_memory_usage ();
3227 * ######################################################################
3228 * ######## Finalization support
3229 * ######################################################################
3233 * If the object has been forwarded it means it's still referenced from a root.
3234 * If it is pinned it's still alive as well.
3235 * A LOS object is only alive if we have pinned it.
3236 * Return TRUE if @obj is ready to be finalized.
3238 static inline gboolean
3239 sgen_is_object_alive (void *object)
3241 if (ptr_in_nursery (object))
3242 return sgen_nursery_is_object_alive (object);
3243 /* Oldgen objects can be pinned and forwarded too */
3244 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3246 return major_collector.is_object_live (object);
3250 sgen_gc_is_object_ready_for_finalization (void *object)
3252 return !sgen_is_object_alive (object);
3256 has_critical_finalizer (MonoObject *obj)
3260 if (!mono_defaults.critical_finalizer_object)
3263 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3265 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3269 queue_finalization_entry (MonoObject *obj) {
3270 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3271 entry->object = obj;
3272 if (has_critical_finalizer (obj)) {
3273 entry->next = critical_fin_list;
3274 critical_fin_list = entry;
3276 entry->next = fin_ready_list;
3277 fin_ready_list = entry;
3282 object_is_reachable (char *object, char *start, char *end)
3284 /*This happens for non nursery objects during minor collections. We just treat all objects as alive.*/
3285 if (object < start || object >= end)
3288 return sgen_is_object_alive (object);
3291 #include "sgen-fin-weak-hash.c"
3294 sgen_object_is_live (void *obj)
3296 if (ptr_in_nursery (obj))
3297 return object_is_pinned (obj);
3298 /* FIXME This is semantically wrong! All tenured object are considered alive during a nursery collection. */
3299 if (current_collection_generation == GENERATION_NURSERY)
3301 return major_collector.is_object_live (obj);
3304 /* LOCKING: requires that the GC lock is held */
3306 null_ephemerons_for_domain (MonoDomain *domain)
3308 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3311 MonoObject *object = (MonoObject*)current->array;
3313 if (object && !object->vtable) {
3314 EphemeronLinkNode *tmp = current;
3317 prev->next = current->next;
3319 ephemeron_list = current->next;
3321 current = current->next;
3322 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3325 current = current->next;
3330 /* LOCKING: requires that the GC lock is held */
3332 clear_unreachable_ephemerons (CopyOrMarkObjectFunc copy_func, char *start, char *end, GrayQueue *queue)
3334 int was_in_nursery, was_promoted;
3335 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3337 Ephemeron *cur, *array_end;
3341 char *object = current->array;
3343 if (!object_is_reachable (object, start, end)) {
3344 EphemeronLinkNode *tmp = current;
3346 DEBUG (5, fprintf (gc_debug_file, "Dead Ephemeron array at %p\n", object));
3349 prev->next = current->next;
3351 ephemeron_list = current->next;
3353 current = current->next;
3354 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3359 was_in_nursery = ptr_in_nursery (object);
3360 copy_func ((void**)&object, queue);
3361 current->array = object;
3363 /*The array was promoted, add global remsets for key/values left behind in nursery.*/
3364 was_promoted = was_in_nursery && !ptr_in_nursery (object);
3366 DEBUG (5, fprintf (gc_debug_file, "Clearing unreachable entries for ephemeron array at %p\n", object));
3368 array = (MonoArray*)object;
3369 cur = mono_array_addr (array, Ephemeron, 0);
3370 array_end = cur + mono_array_length_fast (array);
3371 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3373 for (; cur < array_end; ++cur) {
3374 char *key = (char*)cur->key;
3376 if (!key || key == tombstone)
3379 DEBUG (5, fprintf (gc_debug_file, "[%td] key %p (%s) value %p (%s)\n", cur - mono_array_addr (array, Ephemeron, 0),
3380 key, object_is_reachable (key, start, end) ? "reachable" : "unreachable",
3381 cur->value, cur->value && object_is_reachable (cur->value, start, end) ? "reachable" : "unreachable"));
3383 if (!object_is_reachable (key, start, end)) {
3384 cur->key = tombstone;
3390 if (ptr_in_nursery (key)) {/*key was not promoted*/
3391 DEBUG (5, fprintf (gc_debug_file, "\tAdded remset to key %p\n", key));
3392 sgen_add_to_global_remset (&cur->key);
3394 if (ptr_in_nursery (cur->value)) {/*value was not promoted*/
3395 DEBUG (5, fprintf (gc_debug_file, "\tAdded remset to value %p\n", cur->value));
3396 sgen_add_to_global_remset (&cur->value);
3401 current = current->next;
3405 /* LOCKING: requires that the GC lock is held */
3407 mark_ephemerons_in_range (CopyOrMarkObjectFunc copy_func, char *start, char *end, GrayQueue *queue)
3409 int nothing_marked = 1;
3410 EphemeronLinkNode *current = ephemeron_list;
3412 Ephemeron *cur, *array_end;
3415 for (current = ephemeron_list; current; current = current->next) {
3416 char *object = current->array;
3417 DEBUG (5, fprintf (gc_debug_file, "Ephemeron array at %p\n", object));
3420 For now we process all ephemerons during all collections.
3421 Ideally we should use remset information to partially scan those
3423 We already emit write barriers for Ephemeron fields, it's
3424 just that we don't process them.
3426 /*if (object < start || object >= end)
3429 /*It has to be alive*/
3430 if (!object_is_reachable (object, start, end)) {
3431 DEBUG (5, fprintf (gc_debug_file, "\tnot reachable\n"));
3435 copy_func ((void**)&object, queue);
3437 array = (MonoArray*)object;
3438 cur = mono_array_addr (array, Ephemeron, 0);
3439 array_end = cur + mono_array_length_fast (array);
3440 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3442 for (; cur < array_end; ++cur) {
3443 char *key = cur->key;
3445 if (!key || key == tombstone)
3448 DEBUG (5, fprintf (gc_debug_file, "[%td] key %p (%s) value %p (%s)\n", cur - mono_array_addr (array, Ephemeron, 0),
3449 key, object_is_reachable (key, start, end) ? "reachable" : "unreachable",
3450 cur->value, cur->value && object_is_reachable (cur->value, start, end) ? "reachable" : "unreachable"));
3452 if (object_is_reachable (key, start, end)) {
3453 char *value = cur->value;
3455 copy_func ((void**)&cur->key, queue);
3457 if (!object_is_reachable (value, start, end))
3459 copy_func ((void**)&cur->value, queue);
3465 DEBUG (5, fprintf (gc_debug_file, "Ephemeron run finished. Is it done %d\n", nothing_marked));
3466 return nothing_marked;
3470 mono_gc_invoke_finalizers (void)
3472 FinalizeReadyEntry *entry = NULL;
3473 gboolean entry_is_critical = FALSE;
3476 /* FIXME: batch to reduce lock contention */
3477 while (fin_ready_list || critical_fin_list) {
3481 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3483 /* We have finalized entry in the last
3484 interation, now we need to remove it from
3487 *list = entry->next;
3489 FinalizeReadyEntry *e = *list;
3490 while (e->next != entry)
3492 e->next = entry->next;
3494 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3498 /* Now look for the first non-null entry. */
3499 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3502 entry_is_critical = FALSE;
3504 entry_is_critical = TRUE;
3505 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3510 g_assert (entry->object);
3511 num_ready_finalizers--;
3512 obj = entry->object;
3513 entry->object = NULL;
3514 DEBUG (7, fprintf (gc_debug_file, "Finalizing object %p (%s)\n", obj, safe_name (obj)));
3522 g_assert (entry->object == NULL);
3524 /* the object is on the stack so it is pinned */
3525 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3526 mono_gc_run_finalize (obj, NULL);
3533 mono_gc_pending_finalizers (void)
3535 return fin_ready_list || critical_fin_list;
3538 /* Negative value to remove */
3540 mono_gc_add_memory_pressure (gint64 value)
3542 /* FIXME: Use interlocked functions */
3544 memory_pressure += value;
3549 sgen_register_major_sections_alloced (int num_sections)
3551 minor_collection_sections_alloced += num_sections;
3555 sgen_get_minor_collection_allowance (void)
3557 return minor_collection_allowance;
3561 * ######################################################################
3562 * ######## registered roots support
3563 * ######################################################################
3567 * We do not coalesce roots.
3570 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3572 RootRecord new_root;
3575 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3576 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3577 /* we allow changing the size and the descriptor (for thread statics etc) */
3579 size_t old_size = root->end_root - start;
3580 root->end_root = start + size;
3581 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3582 ((root->root_desc == 0) && (descr == NULL)));
3583 root->root_desc = (mword)descr;
3585 roots_size -= old_size;
3591 new_root.end_root = start + size;
3592 new_root.root_desc = (mword)descr;
3594 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3597 DEBUG (3, fprintf (gc_debug_file, "Added root for range: %p-%p, descr: %p (%d/%d bytes)\n", start, new_root.end_root, descr, (int)size, (int)roots_size));
3604 mono_gc_register_root (char *start, size_t size, void *descr)
3606 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3610 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3612 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3616 mono_gc_deregister_root (char* addr)
3622 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3623 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3624 roots_size -= (root.end_root - addr);
3630 * ######################################################################
3631 * ######## Thread handling (stop/start code)
3632 * ######################################################################
3635 unsigned int sgen_global_stop_count = 0;
3638 static MonoContext cur_thread_ctx = {0};
3640 static mword cur_thread_regs [ARCH_NUM_REGS] = {0};
3644 update_current_thread_stack (void *start)
3646 int stack_guard = 0;
3647 #ifndef USE_MONO_CTX
3648 void *ptr = cur_thread_regs;
3650 SgenThreadInfo *info = mono_thread_info_current ();
3652 info->stack_start = align_pointer (&stack_guard);
3653 g_assert (info->stack_start >= info->stack_start_limit && info->stack_start < info->stack_end);
3655 MONO_CONTEXT_GET_CURRENT (cur_thread_ctx);
3656 info->monoctx = &cur_thread_ctx;
3658 ARCH_STORE_REGS (ptr);
3659 info->stopped_regs = ptr;
3661 if (gc_callbacks.thread_suspend_func)
3662 gc_callbacks.thread_suspend_func (info->runtime_data, NULL);
3666 sgen_fill_thread_info_for_suspend (SgenThreadInfo *info)
3668 if (remset.fill_thread_info_for_suspend)
3669 remset.fill_thread_info_for_suspend (info);
3673 is_ip_in_managed_allocator (MonoDomain *domain, gpointer ip);
3676 restart_threads_until_none_in_managed_allocator (void)
3678 SgenThreadInfo *info;
3679 int num_threads_died = 0;
3680 int sleep_duration = -1;
3683 int restart_count = 0, restarted_count = 0;
3684 /* restart all threads that stopped in the
3686 FOREACH_THREAD_SAFE (info) {
3688 if (info->skip || info->gc_disabled || !info->joined_stw)
3690 if (!info->thread_is_dying && (!info->stack_start || info->in_critical_region ||
3691 is_ip_in_managed_allocator (info->stopped_domain, info->stopped_ip))) {
3692 binary_protocol_thread_restart ((gpointer)mono_thread_info_get_tid (info));
3693 result = sgen_resume_thread (info);
3700 /* we set the stopped_ip to
3701 NULL for threads which
3702 we're not restarting so
3703 that we can easily identify
3705 info->stopped_ip = NULL;
3706 info->stopped_domain = NULL;
3708 } END_FOREACH_THREAD_SAFE
3709 /* if no threads were restarted, we're done */
3710 if (restart_count == 0)
3713 /* wait for the threads to signal their restart */
3714 sgen_wait_for_suspend_ack (restart_count);
3716 if (sleep_duration < 0) {
3724 g_usleep (sleep_duration);
3725 sleep_duration += 10;
3728 /* stop them again */
3729 FOREACH_THREAD (info) {
3731 if (info->skip || info->stopped_ip == NULL)
3733 result = sgen_suspend_thread (info);
3740 } END_FOREACH_THREAD
3741 /* some threads might have died */
3742 num_threads_died += restart_count - restarted_count;
3743 /* wait for the threads to signal their suspension
3745 sgen_wait_for_suspend_ack (restarted_count);
3748 return num_threads_died;
3752 acquire_gc_locks (void)
3755 mono_thread_info_suspend_lock ();
3759 release_gc_locks (void)
3761 mono_thread_info_suspend_unlock ();
3762 UNLOCK_INTERRUPTION;
3765 static TV_DECLARE (stop_world_time);
3766 static unsigned long max_pause_usec = 0;
3768 /* LOCKING: assumes the GC lock is held */
3770 stop_world (int generation)
3774 /*XXX this is the right stop, thought might not be the nicest place to put it*/
3775 sgen_process_togglerefs ();
3777 mono_profiler_gc_event (MONO_GC_EVENT_PRE_STOP_WORLD, generation);
3778 acquire_gc_locks ();
3780 update_current_thread_stack (&count);
3782 sgen_global_stop_count++;
3783 DEBUG (3, fprintf (gc_debug_file, "stopping world n %d from %p %p\n", sgen_global_stop_count, mono_thread_info_current (), (gpointer)mono_native_thread_id_get ()));
3784 TV_GETTIME (stop_world_time);
3785 count = sgen_thread_handshake (TRUE);
3786 dead = restart_threads_until_none_in_managed_allocator ();
3788 g_error ("More threads have died (%d) that been initialy suspended %d", dead, count);
3791 DEBUG (3, fprintf (gc_debug_file, "world stopped %d thread(s)\n", count));
3792 mono_profiler_gc_event (MONO_GC_EVENT_POST_STOP_WORLD, generation);
3794 last_major_num_sections = major_collector.get_num_major_sections ();
3795 last_los_memory_usage = los_memory_usage;
3796 major_collection_happened = FALSE;
3800 /* LOCKING: assumes the GC lock is held */
3802 restart_world (int generation)
3804 int count, num_major_sections;
3805 SgenThreadInfo *info;
3806 TV_DECLARE (end_sw);
3807 TV_DECLARE (end_bridge);
3808 unsigned long usec, bridge_usec;
3810 /* notify the profiler of the leftovers */
3811 if (G_UNLIKELY (mono_profiler_events & MONO_PROFILE_GC_MOVES)) {
3812 if (moved_objects_idx) {
3813 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
3814 moved_objects_idx = 0;
3817 mono_profiler_gc_event (MONO_GC_EVENT_PRE_START_WORLD, generation);
3818 FOREACH_THREAD (info) {
3819 info->stack_start = NULL;
3821 info->monoctx = NULL;
3823 info->stopped_regs = NULL;
3825 } END_FOREACH_THREAD
3827 stw_bridge_process ();
3828 release_gc_locks ();
3830 count = sgen_thread_handshake (FALSE);
3831 TV_GETTIME (end_sw);
3832 usec = TV_ELAPSED (stop_world_time, end_sw);
3833 max_pause_usec = MAX (usec, max_pause_usec);
3834 DEBUG (2, fprintf (gc_debug_file, "restarted %d thread(s) (pause time: %d usec, max: %d)\n", count, (int)usec, (int)max_pause_usec));
3835 mono_profiler_gc_event (MONO_GC_EVENT_POST_START_WORLD, generation);
3839 TV_GETTIME (end_bridge);
3840 bridge_usec = TV_ELAPSED (end_sw, end_bridge);
3842 num_major_sections = major_collector.get_num_major_sections ();
3843 if (major_collection_happened)
3844 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MAJOR: %s pause %.2fms, bridge %.2fms major %dK/%dK los %dK/%dK",
3845 generation ? "" : "(minor overflow)",
3846 (int)usec / 1000.0f, (int)bridge_usec / 1000.0f,
3847 major_collector.section_size * num_major_sections / 1024,
3848 major_collector.section_size * last_major_num_sections / 1024,
3849 los_memory_usage / 1024,
3850 last_los_memory_usage / 1024);
3852 mono_trace (G_LOG_LEVEL_INFO, MONO_TRACE_GC, "GC_MINOR: pause %.2fms, bridge %.2fms promoted %dK major %dK los %dK",
3853 (int)usec / 1000.0f, (int)bridge_usec / 1000.0f,
3854 (num_major_sections - last_major_num_sections) * major_collector.section_size / 1024,
3855 major_collector.section_size * num_major_sections / 1024,
3856 los_memory_usage / 1024);
3862 sgen_get_current_collection_generation (void)
3864 return current_collection_generation;
3868 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3870 gc_callbacks = *callbacks;
3874 mono_gc_get_gc_callbacks ()
3876 return &gc_callbacks;
3879 /* Variables holding start/end nursery so it won't have to be passed at every call */
3880 static void *scan_area_arg_start, *scan_area_arg_end;
3883 mono_gc_conservatively_scan_area (void *start, void *end)
3885 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3889 mono_gc_scan_object (void *obj)
3891 UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3892 current_object_ops.copy_or_mark_object (&obj, data->queue);
3897 * Mark from thread stacks and registers.
3900 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3902 SgenThreadInfo *info;
3904 scan_area_arg_start = start_nursery;
3905 scan_area_arg_end = end_nursery;
3907 FOREACH_THREAD (info) {
3909 DEBUG (3, fprintf (gc_debug_file, "Skipping dead thread %p, range: %p-%p, size: %td\n", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start));
3912 if (info->gc_disabled) {
3913 DEBUG (3, fprintf (gc_debug_file, "GC disabled for thread %p, range: %p-%p, size: %td\n", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start));
3917 if (!info->joined_stw) {
3918 DEBUG (3, fprintf (gc_debug_file, "Skipping thread not seen in STW %p, range: %p-%p, size: %td\n", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start));
3922 DEBUG (3, fprintf (gc_debug_file, "Scanning thread %p, range: %p-%p, size: %td, pinned=%d\n", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, sgen_get_pinned_count ()));
3923 if (!info->thread_is_dying) {
3924 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3925 UserCopyOrMarkData data = { NULL, queue };
3926 set_user_copy_or_mark_data (&data);
3927 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
3928 set_user_copy_or_mark_data (NULL);
3929 } else if (!precise) {
3930 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3935 if (!info->thread_is_dying && !precise)
3936 conservatively_pin_objects_from ((void**)info->monoctx, (void**)info->monoctx + ARCH_NUM_REGS,
3937 start_nursery, end_nursery, PIN_TYPE_STACK);
3939 if (!info->thread_is_dying && !precise)
3940 conservatively_pin_objects_from (info->stopped_regs, info->stopped_regs + ARCH_NUM_REGS,
3941 start_nursery, end_nursery, PIN_TYPE_STACK);
3943 } END_FOREACH_THREAD
3947 find_pinning_ref_from_thread (char *obj, size_t size)
3950 SgenThreadInfo *info;
3951 char *endobj = obj + size;
3953 FOREACH_THREAD (info) {
3954 char **start = (char**)info->stack_start;
3957 while (start < (char**)info->stack_end) {
3958 if (*start >= obj && *start < endobj) {
3959 DEBUG (0, fprintf (gc_debug_file, "Object %p referenced in thread %p (id %p) at %p, stack: %p-%p\n", obj, info, (gpointer)mono_thread_info_get_tid (info), start, info->stack_start, info->stack_end));
3964 for (j = 0; j < ARCH_NUM_REGS; ++j) {
3966 mword w = ((mword*)info->monoctx) [j];
3968 mword w = (mword)info->stopped_regs [j];
3971 if (w >= (mword)obj && w < (mword)obj + size)
3972 DEBUG (0, fprintf (gc_debug_file, "Object %p referenced in saved reg %d of thread %p (id %p)\n", obj, j, info, (gpointer)mono_thread_info_get_tid (info)));
3973 } END_FOREACH_THREAD
3978 ptr_on_stack (void *ptr)
3980 gpointer stack_start = &stack_start;
3981 SgenThreadInfo *info = mono_thread_info_current ();
3983 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3989 sgen_thread_register (SgenThreadInfo* info, void *addr)
3991 #ifndef HAVE_KW_THREAD
3992 SgenThreadInfo *__thread_info__ = info;
3996 #ifndef HAVE_KW_THREAD
3997 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3999 g_assert (!mono_native_tls_get_value (thread_info_key));
4000 mono_native_tls_set_value (thread_info_key, info);
4005 #if !defined(__MACH__)
4006 info->stop_count = -1;
4010 info->joined_stw = FALSE;
4011 info->doing_handshake = FALSE;
4012 info->thread_is_dying = FALSE;
4013 info->stack_start = NULL;
4014 info->store_remset_buffer_addr = &STORE_REMSET_BUFFER;
4015 info->store_remset_buffer_index_addr = &STORE_REMSET_BUFFER_INDEX;
4016 info->stopped_ip = NULL;
4017 info->stopped_domain = NULL;
4019 info->monoctx = NULL;
4021 info->stopped_regs = NULL;
4024 sgen_init_tlab_info (info);
4026 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
4028 #ifdef HAVE_KW_THREAD
4029 store_remset_buffer_index_addr = &store_remset_buffer_index;
4032 #if defined(__MACH__)
4033 info->mach_port = mach_thread_self ();
4036 /* try to get it with attributes first */
4037 #if defined(HAVE_PTHREAD_GETATTR_NP) && defined(HAVE_PTHREAD_ATTR_GETSTACK)
4041 pthread_attr_t attr;
4042 pthread_getattr_np (pthread_self (), &attr);
4043 pthread_attr_getstack (&attr, &sstart, &size);
4044 info->stack_start_limit = sstart;
4045 info->stack_end = (char*)sstart + size;
4046 pthread_attr_destroy (&attr);
4048 #elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP) && defined(HAVE_PTHREAD_GET_STACKADDR_NP)
4049 info->stack_end = (char*)pthread_get_stackaddr_np (pthread_self ());
4050 info->stack_start_limit = (char*)info->stack_end - pthread_get_stacksize_np (pthread_self ());
4053 /* FIXME: we assume the stack grows down */
4054 gsize stack_bottom = (gsize)addr;
4055 stack_bottom += 4095;
4056 stack_bottom &= ~4095;
4057 info->stack_end = (char*)stack_bottom;
4061 #ifdef HAVE_KW_THREAD
4062 stack_end = info->stack_end;
4065 if (remset.register_thread)
4066 remset.register_thread (info);
4068 DEBUG (3, fprintf (gc_debug_file, "registered thread %p (%p) stack end %p\n", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end));
4070 if (gc_callbacks.thread_attach_func)
4071 info->runtime_data = gc_callbacks.thread_attach_func ();
4078 sgen_wbarrier_cleanup_thread (SgenThreadInfo *p)
4080 if (remset.cleanup_thread)
4081 remset.cleanup_thread (p);
4085 sgen_thread_unregister (SgenThreadInfo *p)
4087 /* If a delegate is passed to native code and invoked on a thread we dont
4088 * know about, the jit will register it with mono_jit_thread_attach, but
4089 * we have no way of knowing when that thread goes away. SGen has a TSD
4090 * so we assume that if the domain is still registered, we can detach
4093 if (mono_domain_get ())
4094 mono_thread_detach (mono_thread_current ());
4096 p->thread_is_dying = TRUE;
4099 There is a race condition between a thread finishing executing and been removed
4100 from the GC thread set.
4101 This happens on posix systems when TLS data is been cleaned-up, libpthread will
4102 set the thread_info slot to NULL before calling the cleanup function. This
4103 opens a window in which the thread is registered but has a NULL TLS.
4105 The suspend signal handler needs TLS data to know where to store thread state
4106 data or otherwise it will simply ignore the thread.
4108 This solution works because the thread doing STW will wait until all threads been
4109 suspended handshake back, so there is no race between the doing_hankshake test
4110 and the suspend_thread call.
4112 This is not required on systems that do synchronous STW as those can deal with
4113 the above race at suspend time.
4115 FIXME: I believe we could avoid this by using mono_thread_info_lookup when
4116 mono_thread_info_current returns NULL. Or fix mono_thread_info_lookup to do so.
4118 #if (defined(__MACH__) && MONO_MACH_ARCH_SUPPORTED) || !defined(HAVE_PTHREAD_KILL)
4121 while (!TRYLOCK_GC) {
4122 if (!sgen_park_current_thread_if_doing_handshake (p))
4127 binary_protocol_thread_unregister ((gpointer)mono_thread_info_get_tid (p));
4128 DEBUG (3, fprintf (gc_debug_file, "unregister thread %p (%p)\n", p, (gpointer)mono_thread_info_get_tid (p)));
4130 #if defined(__MACH__)
4131 mach_port_deallocate (current_task (), p->mach_port);
4134 if (gc_callbacks.thread_detach_func) {
4135 gc_callbacks.thread_detach_func (p->runtime_data);
4136 p->runtime_data = NULL;
4138 sgen_wbarrier_cleanup_thread (p);
4140 mono_threads_unregister_current_thread (p);
4146 sgen_thread_attach (SgenThreadInfo *info)
4149 /*this is odd, can we get attached before the gc is inited?*/
4153 if (gc_callbacks.thread_attach_func && !info->runtime_data)
4154 info->runtime_data = gc_callbacks.thread_attach_func ();
4157 mono_gc_register_thread (void *baseptr)
4159 return mono_thread_info_attach (baseptr) != NULL;
4163 * mono_gc_set_stack_end:
4165 * Set the end of the current threads stack to STACK_END. The stack space between
4166 * STACK_END and the real end of the threads stack will not be scanned during collections.
4169 mono_gc_set_stack_end (void *stack_end)
4171 SgenThreadInfo *info;
4174 info = mono_thread_info_current ();
4176 g_assert (stack_end < info->stack_end);
4177 info->stack_end = stack_end;
4182 #if USE_PTHREAD_INTERCEPT
4186 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4188 return pthread_create (new_thread, attr, start_routine, arg);
4192 mono_gc_pthread_join (pthread_t thread, void **retval)
4194 return pthread_join (thread, retval);
4198 mono_gc_pthread_detach (pthread_t thread)
4200 return pthread_detach (thread);
4204 mono_gc_pthread_exit (void *retval)
4206 pthread_exit (retval);
4209 #endif /* USE_PTHREAD_INTERCEPT */
4212 * ######################################################################
4213 * ######## Write barriers
4214 * ######################################################################
4218 * Note: the write barriers first do the needed GC work and then do the actual store:
4219 * this way the value is visible to the conservative GC scan after the write barrier
4220 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4221 * the conservative scan, otherwise by the remembered set scan.
4224 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4226 HEAVY_STAT (++stat_wbarrier_set_field);
4227 if (ptr_in_nursery (field_ptr)) {
4228 *(void**)field_ptr = value;
4231 DEBUG (8, fprintf (gc_debug_file, "Adding remset at %p\n", field_ptr));
4233 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4235 remset.wbarrier_set_field (obj, field_ptr, value);
4239 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4241 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4242 if (ptr_in_nursery (slot_ptr)) {
4243 *(void**)slot_ptr = value;
4246 DEBUG (8, fprintf (gc_debug_file, "Adding remset at %p\n", slot_ptr));
4248 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4250 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4254 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4256 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4257 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4258 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4259 mono_gc_memmove (dest_ptr, src_ptr, count * sizeof (gpointer));
4263 #ifdef SGEN_BINARY_PROTOCOL
4266 for (i = 0; i < count; ++i) {
4267 gpointer dest = (gpointer*)dest_ptr + i;
4268 gpointer obj = *((gpointer*)src_ptr + i);
4270 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4275 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4278 static char *found_obj;
4281 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4283 char *ptr = user_data;
4285 if (ptr >= obj && ptr < obj + size) {
4286 g_assert (!found_obj);
4291 /* for use in the debugger */
4292 char* find_object_for_ptr (char *ptr);
4294 find_object_for_ptr (char *ptr)
4296 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4298 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4299 find_object_for_ptr_callback, ptr, TRUE);
4305 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4310 * Very inefficient, but this is debugging code, supposed to
4311 * be called from gdb, so we don't care.
4314 major_collector.iterate_objects (TRUE, TRUE, find_object_for_ptr_callback, ptr);
4319 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4321 HEAVY_STAT (++stat_wbarrier_generic_store);
4323 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4324 /* FIXME: ptr_in_heap must be called with the GC lock held */
4325 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4326 char *start = find_object_for_ptr (ptr);
4327 MonoObject *value = *(MonoObject**)ptr;
4331 MonoObject *obj = (MonoObject*)start;
4332 if (obj->vtable->domain != value->vtable->domain)
4333 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4339 if (*(gpointer*)ptr)
4340 binary_protocol_wbarrier (ptr, *(gpointer*)ptr, (gpointer)LOAD_VTABLE (*(gpointer*)ptr));
4342 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr) || !ptr_in_nursery (*(gpointer*)ptr)) {
4343 DEBUG (8, fprintf (gc_debug_file, "Skipping remset at %p\n", ptr));
4347 DEBUG (8, fprintf (gc_debug_file, "Adding remset at %p\n", ptr));
4349 remset.wbarrier_generic_nostore (ptr);
4353 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4355 DEBUG (8, fprintf (gc_debug_file, "Wbarrier store at %p to %p (%s)\n", ptr, value, value ? safe_name (value) : "null"));
4356 *(void**)ptr = value;
4357 if (ptr_in_nursery (value))
4358 mono_gc_wbarrier_generic_nostore (ptr);
4359 sgen_dummy_use (value);
4362 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4364 mword *dest = _dest;
4369 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4374 size -= SIZEOF_VOID_P;
4379 #ifdef SGEN_BINARY_PROTOCOL
4381 #define HANDLE_PTR(ptr,obj) do { \
4382 gpointer o = *(gpointer*)(ptr); \
4384 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4385 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4390 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4392 #define SCAN_OBJECT_NOVTABLE
4393 #include "sgen-scan-object.h"
4398 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4400 HEAVY_STAT (++stat_wbarrier_value_copy);
4401 g_assert (klass->valuetype);
4403 DEBUG (8, fprintf (gc_debug_file, "Adding value remset at %p, count %d, descr %p for class %s (%p)\n", dest, count, klass->gc_descr, klass->name, klass));
4405 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4406 size_t element_size = mono_class_value_size (klass, NULL);
4407 size_t size = count * element_size;
4408 mono_gc_memmove (dest, src, size);
4412 #ifdef SGEN_BINARY_PROTOCOL
4415 for (i = 0; i < count; ++i) {
4416 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4417 (char*)src + i * element_size - sizeof (MonoObject),
4418 (mword) klass->gc_descr);
4423 remset.wbarrier_value_copy (dest, src, count, klass);
4427 * mono_gc_wbarrier_object_copy:
4429 * Write barrier to call when obj is the result of a clone or copy of an object.
4432 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4436 HEAVY_STAT (++stat_wbarrier_object_copy);
4438 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4439 size = mono_object_class (obj)->instance_size;
4440 mono_gc_memmove ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4441 size - sizeof (MonoObject));
4445 #ifdef SGEN_BINARY_PROTOCOL
4446 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4449 remset.wbarrier_object_copy (obj, src);
4454 * ######################################################################
4455 * ######## Other mono public interface functions.
4456 * ######################################################################
4459 #define REFS_SIZE 128
4462 MonoGCReferences callback;
4466 MonoObject *refs [REFS_SIZE];
4467 uintptr_t offsets [REFS_SIZE];
4471 #define HANDLE_PTR(ptr,obj) do { \
4473 if (hwi->count == REFS_SIZE) { \
4474 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4478 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4479 hwi->refs [hwi->count++] = *(ptr); \
4484 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4486 #include "sgen-scan-object.h"
4490 walk_references (char *start, size_t size, void *data)
4492 HeapWalkInfo *hwi = data;
4495 collect_references (hwi, start, size);
4496 if (hwi->count || !hwi->called)
4497 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4501 * mono_gc_walk_heap:
4502 * @flags: flags for future use
4503 * @callback: a function pointer called for each object in the heap
4504 * @data: a user data pointer that is passed to callback
4506 * This function can be used to iterate over all the live objects in the heap:
4507 * for each object, @callback is invoked, providing info about the object's
4508 * location in memory, its class, its size and the objects it references.
4509 * For each referenced object it's offset from the object address is
4510 * reported in the offsets array.
4511 * The object references may be buffered, so the callback may be invoked
4512 * multiple times for the same object: in all but the first call, the size
4513 * argument will be zero.
4514 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4515 * profiler event handler.
4517 * Returns: a non-zero value if the GC doesn't support heap walking
4520 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4525 hwi.callback = callback;
4528 sgen_clear_nursery_fragments ();
4529 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4531 major_collector.iterate_objects (TRUE, TRUE, walk_references, &hwi);
4532 sgen_los_iterate_objects (walk_references, &hwi);
4538 mono_gc_collect (int generation)
4543 mono_profiler_gc_event (MONO_GC_EVENT_START, generation);
4544 stop_world (generation);
4545 if (generation == 0) {
4546 collect_nursery (0);
4548 major_collection ("user request");
4550 restart_world (generation);
4551 mono_profiler_gc_event (MONO_GC_EVENT_END, generation);
4556 mono_gc_max_generation (void)
4562 mono_gc_collection_count (int generation)
4564 if (generation == 0)
4565 return stat_minor_gcs;
4566 return stat_major_gcs;
4570 mono_gc_get_used_size (void)
4574 tot = los_memory_usage;
4575 tot += nursery_section->next_data - nursery_section->data;
4576 tot += major_collector.get_used_size ();
4577 /* FIXME: account for pinned objects */
4583 mono_gc_get_heap_size (void)
4589 mono_gc_disable (void)
4597 mono_gc_enable (void)
4605 mono_gc_get_los_limit (void)
4607 return MAX_SMALL_OBJ_SIZE;
4611 mono_object_is_alive (MonoObject* o)
4617 mono_gc_get_generation (MonoObject *obj)
4619 if (ptr_in_nursery (obj))
4625 mono_gc_enable_events (void)
4630 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4632 mono_gc_register_disappearing_link (obj, link_addr, track, FALSE);
4636 mono_gc_weak_link_remove (void **link_addr)
4638 mono_gc_register_disappearing_link (NULL, link_addr, FALSE, FALSE);
4642 mono_gc_weak_link_get (void **link_addr)
4646 return (MonoObject*) REVEAL_POINTER (*link_addr);
4650 mono_gc_ephemeron_array_add (MonoObject *obj)
4652 EphemeronLinkNode *node;
4656 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4661 node->array = (char*)obj;
4662 node->next = ephemeron_list;
4663 ephemeron_list = node;
4665 DEBUG (5, fprintf (gc_debug_file, "Registered ephemeron array %p\n", obj));
4672 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4676 result = func (data);
4677 UNLOCK_INTERRUPTION;
4682 mono_gc_is_gc_thread (void)
4686 result = mono_thread_info_current () != NULL;
4692 is_critical_method (MonoMethod *method)
4694 return mono_runtime_is_critical_method (method) || mono_gc_is_critical_method (method);
4698 mono_gc_base_init (void)
4700 MonoThreadInfoCallbacks cb;
4703 char *major_collector_opt = NULL;
4704 char *minor_collector_opt = NULL;
4706 glong soft_limit = 0;
4712 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4715 /* already inited */
4718 /* being inited by another thread */
4722 /* we will init it */
4725 g_assert_not_reached ();
4727 } while (result != 0);
4729 LOCK_INIT (gc_mutex);
4731 pagesize = mono_pagesize ();
4732 gc_debug_file = stderr;
4734 cb.thread_register = sgen_thread_register;
4735 cb.thread_unregister = sgen_thread_unregister;
4736 cb.thread_attach = sgen_thread_attach;
4737 cb.mono_method_is_critical = (gpointer)is_critical_method;
4739 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4742 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4744 LOCK_INIT (interruption_mutex);
4745 LOCK_INIT (pin_queue_mutex);
4747 init_user_copy_or_mark_key ();
4749 if ((env = getenv ("MONO_GC_PARAMS"))) {
4750 opts = g_strsplit (env, ",", -1);
4751 for (ptr = opts; *ptr; ++ptr) {
4753 if (g_str_has_prefix (opt, "major=")) {
4754 opt = strchr (opt, '=') + 1;
4755 major_collector_opt = g_strdup (opt);
4756 } else if (g_str_has_prefix (opt, "minor=")) {
4757 opt = strchr (opt, '=') + 1;
4758 minor_collector_opt = g_strdup (opt);
4766 sgen_init_internal_allocator ();
4767 sgen_init_nursery_allocator ();
4769 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4770 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4771 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4772 g_assert (sizeof (GenericStoreRememberedSet) == sizeof (gpointer) * STORE_REMSET_BUFFER_SIZE);
4773 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_STORE_REMSET, sizeof (GenericStoreRememberedSet));
4774 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4776 #ifndef HAVE_KW_THREAD
4777 mono_native_tls_alloc (&thread_info_key, NULL);
4781 * This needs to happen before any internal allocations because
4782 * it inits the small id which is required for hazard pointer
4787 mono_thread_info_attach (&dummy);
4789 if (!minor_collector_opt) {
4790 sgen_simple_nursery_init (&sgen_minor_collector);
4792 if (!strcmp (minor_collector_opt, "simple"))
4793 sgen_simple_nursery_init (&sgen_minor_collector);
4794 else if (!strcmp (minor_collector_opt, "split"))
4795 sgen_split_nursery_init (&sgen_minor_collector);
4797 fprintf (stderr, "Unknown minor collector `%s'.\n", minor_collector_opt);
4802 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4803 sgen_marksweep_init (&major_collector);
4804 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4805 sgen_marksweep_fixed_init (&major_collector);
4806 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4807 sgen_marksweep_par_init (&major_collector);
4808 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4809 sgen_marksweep_fixed_par_init (&major_collector);
4810 } else if (!strcmp (major_collector_opt, "copying")) {
4811 sgen_copying_init (&major_collector);
4813 fprintf (stderr, "Unknown major collector `%s'.\n", major_collector_opt);
4817 #ifdef SGEN_HAVE_CARDTABLE
4818 use_cardtable = major_collector.supports_cardtable;
4820 use_cardtable = FALSE;
4823 num_workers = mono_cpu_count ();
4824 g_assert (num_workers > 0);
4825 if (num_workers > 16)
4828 ///* Keep this the default for now */
4830 conservative_stack_mark = TRUE;
4833 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4834 minor_collection_allowance = MIN_MINOR_COLLECTION_ALLOWANCE;
4837 for (ptr = opts; *ptr; ++ptr) {
4839 if (g_str_has_prefix (opt, "major="))
4841 if (g_str_has_prefix (opt, "minor="))
4843 if (g_str_has_prefix (opt, "wbarrier=")) {
4844 opt = strchr (opt, '=') + 1;
4845 if (strcmp (opt, "remset") == 0) {
4846 use_cardtable = FALSE;
4847 } else if (strcmp (opt, "cardtable") == 0) {
4848 if (!use_cardtable) {
4849 if (major_collector.supports_cardtable)
4850 fprintf (stderr, "The cardtable write barrier is not supported on this platform.\n");
4852 fprintf (stderr, "The major collector does not support the cardtable write barrier.\n");
4858 if (g_str_has_prefix (opt, "max-heap-size=")) {
4859 opt = strchr (opt, '=') + 1;
4860 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap)) {
4861 if ((max_heap & (mono_pagesize () - 1))) {
4862 fprintf (stderr, "max-heap-size size must be a multiple of %d.\n", mono_pagesize ());
4866 fprintf (stderr, "max-heap-size must be an integer.\n");
4871 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4872 opt = strchr (opt, '=') + 1;
4873 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4874 if (soft_limit <= 0) {
4875 fprintf (stderr, "soft-heap-limit must be positive.\n");
4879 fprintf (stderr, "soft-heap-limit must be an integer.\n");
4884 if (g_str_has_prefix (opt, "workers=")) {
4887 if (!major_collector.is_parallel) {
4888 fprintf (stderr, "The workers= option can only be used for parallel collectors.");
4891 opt = strchr (opt, '=') + 1;
4892 val = strtol (opt, &endptr, 10);
4893 if (!*opt || *endptr) {
4894 fprintf (stderr, "Cannot parse the workers= option value.");
4897 if (val <= 0 || val > 16) {
4898 fprintf (stderr, "The number of workers must be in the range 1 to 16.");
4901 num_workers = (int)val;
4904 if (g_str_has_prefix (opt, "stack-mark=")) {
4905 opt = strchr (opt, '=') + 1;
4906 if (!strcmp (opt, "precise")) {
4907 conservative_stack_mark = FALSE;
4908 } else if (!strcmp (opt, "conservative")) {
4909 conservative_stack_mark = TRUE;
4911 fprintf (stderr, "Invalid value '%s' for stack-mark= option, possible values are: 'precise', 'conservative'.\n", opt);
4916 if (g_str_has_prefix (opt, "bridge=")) {
4917 opt = strchr (opt, '=') + 1;
4918 sgen_register_test_bridge_callbacks (g_strdup (opt));
4922 if (g_str_has_prefix (opt, "nursery-size=")) {
4924 opt = strchr (opt, '=') + 1;
4925 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4926 sgen_nursery_size = val;
4927 #ifdef SGEN_ALIGN_NURSERY
4928 if ((val & (val - 1))) {
4929 fprintf (stderr, "The nursery size must be a power of two.\n");
4933 if (val < SGEN_MAX_NURSERY_WASTE) {
4934 fprintf (stderr, "The nursery size must be at least %d bytes.\n", SGEN_MAX_NURSERY_WASTE);
4938 sgen_nursery_bits = 0;
4939 while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
4943 fprintf (stderr, "nursery-size must be an integer.\n");
4949 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4952 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4955 fprintf (stderr, "MONO_GC_PARAMS must be a comma-delimited list of one or more of the following:\n");
4956 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4957 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4958 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4959 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-par' or `copying')\n");
4960 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4961 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4962 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4963 if (major_collector.print_gc_param_usage)
4964 major_collector.print_gc_param_usage ();
4965 if (sgen_minor_collector.print_gc_param_usage)
4966 sgen_minor_collector.print_gc_param_usage ();
4972 if (major_collector.is_parallel)
4973 sgen_workers_init (num_workers);
4975 if (major_collector_opt)
4976 g_free (major_collector_opt);
4978 if (minor_collector_opt)
4979 g_free (minor_collector_opt);
4981 init_heap_size_limits (max_heap, soft_limit);
4985 if ((env = getenv ("MONO_GC_DEBUG"))) {
4986 opts = g_strsplit (env, ",", -1);
4987 for (ptr = opts; ptr && *ptr; ptr ++) {
4989 if (opt [0] >= '0' && opt [0] <= '9') {
4990 gc_debug_level = atoi (opt);
4995 char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
4996 gc_debug_file = fopen (rf, "wb");
4998 gc_debug_file = stderr;
5001 } else if (!strcmp (opt, "print-allowance")) {
5002 debug_print_allowance = TRUE;
5003 } else if (!strcmp (opt, "print-pinning")) {
5004 do_pin_stats = TRUE;
5005 } else if (!strcmp (opt, "verify-before-allocs")) {
5006 verify_before_allocs = 1;
5007 has_per_allocation_action = TRUE;
5008 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
5009 char *arg = strchr (opt, '=') + 1;
5010 verify_before_allocs = atoi (arg);
5011 has_per_allocation_action = TRUE;
5012 } else if (!strcmp (opt, "collect-before-allocs")) {
5013 collect_before_allocs = 1;
5014 has_per_allocation_action = TRUE;
5015 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
5016 char *arg = strchr (opt, '=') + 1;
5017 has_per_allocation_action = TRUE;
5018 collect_before_allocs = atoi (arg);
5019 } else if (!strcmp (opt, "verify-before-collections")) {
5020 whole_heap_check_before_collection = TRUE;
5021 } else if (!strcmp (opt, "check-at-minor-collections")) {
5022 consistency_check_at_minor_collection = TRUE;
5023 nursery_clear_policy = CLEAR_AT_GC;
5024 } else if (!strcmp (opt, "xdomain-checks")) {
5025 xdomain_checks = TRUE;
5026 } else if (!strcmp (opt, "clear-at-gc")) {
5027 nursery_clear_policy = CLEAR_AT_GC;
5028 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5029 nursery_clear_policy = CLEAR_AT_GC;
5030 } else if (!strcmp (opt, "check-scan-starts")) {
5031 do_scan_starts_check = TRUE;
5032 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5033 do_verify_nursery = TRUE;
5034 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5035 do_dump_nursery_content = TRUE;
5036 } else if (!strcmp (opt, "disable-minor")) {
5037 disable_minor_collections = TRUE;
5038 } else if (!strcmp (opt, "disable-major")) {
5039 disable_major_collections = TRUE;
5040 } else if (g_str_has_prefix (opt, "heap-dump=")) {
5041 char *filename = strchr (opt, '=') + 1;
5042 nursery_clear_policy = CLEAR_AT_GC;
5043 heap_dump_file = fopen (filename, "w");
5044 if (heap_dump_file) {
5045 fprintf (heap_dump_file, "<sgen-dump>\n");
5046 do_pin_stats = TRUE;
5048 #ifdef SGEN_BINARY_PROTOCOL
5049 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5050 char *filename = strchr (opt, '=') + 1;
5051 binary_protocol_init (filename);
5053 fprintf (stderr, "Warning: Cardtable write barriers will not be binary-protocolled.\n");
5056 fprintf (stderr, "Invalid format for the MONO_GC_DEBUG env variable: '%s'\n", env);
5057 fprintf (stderr, "The format is: MONO_GC_DEBUG=[l[:filename]|<option>]+ where l is a debug level 0-9.\n");
5058 fprintf (stderr, "Valid options are:\n");
5059 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5060 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5061 fprintf (stderr, " check-at-minor-collections\n");
5062 fprintf (stderr, " verify-before-collections\n");
5063 fprintf (stderr, " disable-minor\n");
5064 fprintf (stderr, " disable-major\n");
5065 fprintf (stderr, " xdomain-checks\n");
5066 fprintf (stderr, " clear-at-gc\n");
5067 fprintf (stderr, " print-allowance\n");
5068 fprintf (stderr, " print-pinning\n");
5075 if (major_collector.is_parallel) {
5076 if (heap_dump_file) {
5077 fprintf (stderr, "Error: Cannot do heap dump with the parallel collector.\n");
5081 fprintf (stderr, "Error: Cannot gather pinning statistics with the parallel collector.\n");
5086 if (major_collector.post_param_init)
5087 major_collector.post_param_init ();
5089 memset (&remset, 0, sizeof (remset));
5091 #ifdef SGEN_HAVE_CARDTABLE
5093 sgen_card_table_init (&remset);
5096 sgen_ssb_init (&remset);
5098 if (remset.register_thread)
5099 remset.register_thread (mono_thread_info_current ());
5105 mono_gc_get_gc_name (void)
5110 static MonoMethod *write_barrier_method;
5113 mono_gc_is_critical_method (MonoMethod *method)
5115 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5119 is_ip_in_managed_allocator (MonoDomain *domain, gpointer ip)
5123 if (!mono_thread_internal_current ())
5124 /* Happens during thread attach */
5129 ji = mono_jit_info_table_find (domain, ip);
5133 return mono_gc_is_critical_method (ji->method);
5137 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5139 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5140 #ifdef SGEN_ALIGN_NURSERY
5141 // if (ptr_in_nursery (ptr)) return;
5143 * Masking out the bits might be faster, but we would have to use 64 bit
5144 * immediates, which might be slower.
5146 mono_mb_emit_ldarg (mb, 0);
5147 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5148 mono_mb_emit_byte (mb, CEE_SHR_UN);
5149 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5150 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5152 // if (!ptr_in_nursery (*ptr)) return;
5153 mono_mb_emit_ldarg (mb, 0);
5154 mono_mb_emit_byte (mb, CEE_LDIND_I);
5155 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5156 mono_mb_emit_byte (mb, CEE_SHR_UN);
5157 mono_mb_emit_icon (mb, (mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS);
5158 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5160 int label_continue1, label_continue2;
5161 int dereferenced_var;
5163 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5164 mono_mb_emit_ldarg (mb, 0);
5165 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5166 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5168 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5169 mono_mb_emit_ldarg (mb, 0);
5170 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5171 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5174 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5177 mono_mb_patch_branch (mb, label_continue_1);
5178 mono_mb_patch_branch (mb, label_continue_2);
5180 // Dereference and store in local var
5181 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5182 mono_mb_emit_ldarg (mb, 0);
5183 mono_mb_emit_byte (mb, CEE_LDIND_I);
5184 mono_mb_emit_stloc (mb, dereferenced_var);
5186 // if (*ptr < sgen_get_nursery_start ()) return;
5187 mono_mb_emit_ldloc (mb, dereferenced_var);
5188 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5189 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5191 // if (*ptr >= sgen_get_nursery_end ()) return;
5192 mono_mb_emit_ldloc (mb, dereferenced_var);
5193 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5194 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5199 mono_gc_get_write_barrier (void)
5202 MonoMethodBuilder *mb;
5203 MonoMethodSignature *sig;
5204 #ifdef MANAGED_WBARRIER
5205 int i, nursery_check_labels [3];
5206 int label_no_wb_3, label_no_wb_4, label_need_wb, label_slow_path;
5207 int buffer_var, buffer_index_var, dummy_var;
5209 #ifdef HAVE_KW_THREAD
5210 int stack_end_offset = -1, store_remset_buffer_offset = -1;
5211 int store_remset_buffer_index_offset = -1, store_remset_buffer_index_addr_offset = -1;
5213 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5214 g_assert (stack_end_offset != -1);
5215 MONO_THREAD_VAR_OFFSET (store_remset_buffer, store_remset_buffer_offset);
5216 g_assert (store_remset_buffer_offset != -1);
5217 MONO_THREAD_VAR_OFFSET (store_remset_buffer_index, store_remset_buffer_index_offset);
5218 g_assert (store_remset_buffer_index_offset != -1);
5219 MONO_THREAD_VAR_OFFSET (store_remset_buffer_index_addr, store_remset_buffer_index_addr_offset);
5220 g_assert (store_remset_buffer_index_addr_offset != -1);
5224 // FIXME: Maybe create a separate version for ctors (the branch would be
5225 // correctly predicted more times)
5226 if (write_barrier_method)
5227 return write_barrier_method;
5229 /* Create the IL version of mono_gc_barrier_generic_store () */
5230 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5231 sig->ret = &mono_defaults.void_class->byval_arg;
5232 sig->params [0] = &mono_defaults.int_class->byval_arg;
5234 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5236 #ifdef MANAGED_WBARRIER
5237 if (use_cardtable) {
5238 emit_nursery_check (mb, nursery_check_labels);
5240 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5244 LDC_PTR sgen_cardtable
5246 address >> CARD_BITS
5250 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5251 LDC_PTR card_table_mask
5258 mono_mb_emit_ptr (mb, sgen_cardtable);
5259 mono_mb_emit_ldarg (mb, 0);
5260 mono_mb_emit_icon (mb, CARD_BITS);
5261 mono_mb_emit_byte (mb, CEE_SHR_UN);
5262 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5263 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5264 mono_mb_emit_byte (mb, CEE_AND);
5266 mono_mb_emit_byte (mb, CEE_ADD);
5267 mono_mb_emit_icon (mb, 1);
5268 mono_mb_emit_byte (mb, CEE_STIND_I1);
5271 for (i = 0; i < 3; ++i) {
5272 if (nursery_check_labels [i])
5273 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5275 mono_mb_emit_byte (mb, CEE_RET);
5276 } else if (mono_runtime_has_tls_get ()) {
5277 emit_nursery_check (mb, nursery_check_labels);
5279 // if (ptr >= stack_end) goto need_wb;
5280 mono_mb_emit_ldarg (mb, 0);
5281 EMIT_TLS_ACCESS (mb, stack_end, stack_end_offset);
5282 label_need_wb = mono_mb_emit_branch (mb, CEE_BGE_UN);
5284 // if (ptr >= stack_start) return;
5285 dummy_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5286 mono_mb_emit_ldarg (mb, 0);
5287 mono_mb_emit_ldloc_addr (mb, dummy_var);
5288 label_no_wb_3 = mono_mb_emit_branch (mb, CEE_BGE_UN);
5291 mono_mb_patch_branch (mb, label_need_wb);
5293 // buffer = STORE_REMSET_BUFFER;
5294 buffer_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5295 EMIT_TLS_ACCESS (mb, store_remset_buffer, store_remset_buffer_offset);
5296 mono_mb_emit_stloc (mb, buffer_var);
5298 // buffer_index = STORE_REMSET_BUFFER_INDEX;
5299 buffer_index_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5300 EMIT_TLS_ACCESS (mb, store_remset_buffer_index, store_remset_buffer_index_offset);
5301 mono_mb_emit_stloc (mb, buffer_index_var);
5303 // if (buffer [buffer_index] == ptr) return;
5304 mono_mb_emit_ldloc (mb, buffer_var);
5305 mono_mb_emit_ldloc (mb, buffer_index_var);
5306 g_assert (sizeof (gpointer) == 4 || sizeof (gpointer) == 8);
5307 mono_mb_emit_icon (mb, sizeof (gpointer) == 4 ? 2 : 3);
5308 mono_mb_emit_byte (mb, CEE_SHL);
5309 mono_mb_emit_byte (mb, CEE_ADD);
5310 mono_mb_emit_byte (mb, CEE_LDIND_I);
5311 mono_mb_emit_ldarg (mb, 0);
5312 label_no_wb_4 = mono_mb_emit_branch (mb, CEE_BEQ);
5315 mono_mb_emit_ldloc (mb, buffer_index_var);
5316 mono_mb_emit_icon (mb, 1);
5317 mono_mb_emit_byte (mb, CEE_ADD);
5318 mono_mb_emit_stloc (mb, buffer_index_var);
5320 // if (buffer_index >= STORE_REMSET_BUFFER_SIZE) goto slow_path;
5321 mono_mb_emit_ldloc (mb, buffer_index_var);
5322 mono_mb_emit_icon (mb, STORE_REMSET_BUFFER_SIZE);
5323 label_slow_path = mono_mb_emit_branch (mb, CEE_BGE);
5325 // buffer [buffer_index] = ptr;
5326 mono_mb_emit_ldloc (mb, buffer_var);
5327 mono_mb_emit_ldloc (mb, buffer_index_var);
5328 g_assert (sizeof (gpointer) == 4 || sizeof (gpointer) == 8);
5329 mono_mb_emit_icon (mb, sizeof (gpointer) == 4 ? 2 : 3);
5330 mono_mb_emit_byte (mb, CEE_SHL);
5331 mono_mb_emit_byte (mb, CEE_ADD);
5332 mono_mb_emit_ldarg (mb, 0);
5333 mono_mb_emit_byte (mb, CEE_STIND_I);
5335 // STORE_REMSET_BUFFER_INDEX = buffer_index;
5336 EMIT_TLS_ACCESS (mb, store_remset_buffer_index_addr, store_remset_buffer_index_addr_offset);
5337 mono_mb_emit_ldloc (mb, buffer_index_var);
5338 mono_mb_emit_byte (mb, CEE_STIND_I);
5341 for (i = 0; i < 3; ++i) {
5342 if (nursery_check_labels [i])
5343 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5345 mono_mb_patch_branch (mb, label_no_wb_3);
5346 mono_mb_patch_branch (mb, label_no_wb_4);
5347 mono_mb_emit_byte (mb, CEE_RET);
5350 mono_mb_patch_branch (mb, label_slow_path);
5352 mono_mb_emit_ldarg (mb, 0);
5353 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5354 mono_mb_emit_byte (mb, CEE_RET);
5358 mono_mb_emit_ldarg (mb, 0);
5359 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5360 mono_mb_emit_byte (mb, CEE_RET);
5363 res = mono_mb_create_method (mb, sig, 16);
5366 mono_loader_lock ();
5367 if (write_barrier_method) {
5368 /* Already created */
5369 mono_free_method (res);
5371 /* double-checked locking */
5372 mono_memory_barrier ();
5373 write_barrier_method = res;
5375 mono_loader_unlock ();
5377 return write_barrier_method;
5381 mono_gc_get_description (void)
5383 return g_strdup ("sgen");
5387 mono_gc_set_desktop_mode (void)
5392 mono_gc_is_moving (void)
5398 mono_gc_is_disabled (void)
5404 sgen_debug_printf (int level, const char *format, ...)
5408 if (level > gc_debug_level)
5411 va_start (ap, format);
5412 vfprintf (gc_debug_file, format, ap);
5417 sgen_get_logfile (void)
5419 return gc_debug_file;
5423 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5430 sgen_get_nursery_clear_policy (void)
5432 return nursery_clear_policy;
5436 sgen_get_array_fill_vtable (void)
5438 if (!array_fill_vtable) {
5439 static MonoClass klass;
5440 static MonoVTable vtable;
5443 MonoDomain *domain = mono_get_root_domain ();
5446 klass.element_class = mono_defaults.byte_class;
5448 klass.instance_size = sizeof (MonoArray);
5449 klass.sizes.element_size = 1;
5450 klass.name = "array_filler_type";
5452 vtable.klass = &klass;
5454 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5457 array_fill_vtable = &vtable;
5459 return array_fill_vtable;
5469 sgen_gc_unlock (void)
5475 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5477 major_collector.iterate_live_block_ranges (callback);
5481 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5483 major_collector.scan_card_table (queue);
5487 sgen_get_major_collector (void)
5489 return &major_collector;
5492 void mono_gc_set_skip_thread (gboolean skip)
5494 SgenThreadInfo *info = mono_thread_info_current ();
5497 info->gc_disabled = skip;
5502 sgen_get_remset (void)
5508 mono_gc_get_vtable_bits (MonoClass *class)
5510 if (sgen_need_bridge_processing () && sgen_is_bridge_class (class))
5511 return SGEN_GC_BIT_BRIDGE_OBJECT;
5516 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5523 sgen_check_whole_heap_stw (void)
5526 sgen_clear_nursery_fragments ();
5527 sgen_check_whole_heap ();
5531 #endif /* HAVE_SGEN_GC */