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.
16 * Copyright 2001-2003 Ximian, Inc
17 * Copyright 2003-2010 Novell, Inc.
18 * Copyright 2011 Xamarin, Inc.
19 * Copyright (C) 2012 Xamarin Inc
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Library General Public
23 * License 2.0 as published by the Free Software Foundation;
25 * This library is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
28 * Library General Public License for more details.
30 * You should have received a copy of the GNU Library General Public
31 * License 2.0 along with this library; if not, write to the Free
32 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
34 * Important: allocation provides always zeroed memory, having to do
35 * a memset after allocation is deadly for performance.
36 * Memory usage at startup is currently as follows:
38 * 64 KB internal space
40 * We should provide a small memory config with half the sizes
42 * We currently try to make as few mono assumptions as possible:
43 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
45 * 2) gc descriptor is the second word in the vtable (first word in the class)
46 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
47 * 4) there is a function to get an object's size and the number of
48 * elements in an array.
49 * 5) we know the special way bounds are allocated for complex arrays
50 * 6) we know about proxies and how to treat them when domains are unloaded
52 * Always try to keep stack usage to a minimum: no recursive behaviour
53 * and no large stack allocs.
55 * General description.
56 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
57 * When the nursery is full we start a nursery collection: this is performed with a
59 * When the old generation is full we start a copying GC of the old generation as well:
60 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
61 * in the future. Maybe we'll even do both during the same collection like IMMIX.
63 * The things that complicate this description are:
64 * *) pinned objects: we can't move them so we need to keep track of them
65 * *) no precise info of the thread stacks and registers: we need to be able to
66 * quickly find the objects that may be referenced conservatively and pin them
67 * (this makes the first issues more important)
68 * *) large objects are too expensive to be dealt with using copying GC: we handle them
69 * with mark/sweep during major collections
70 * *) some objects need to not move even if they are small (interned strings, Type handles):
71 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
72 * PinnedChunks regions
78 *) we could have a function pointer in MonoClass to implement
79 customized write barriers for value types
81 *) investigate the stuff needed to advance a thread to a GC-safe
82 point (single-stepping, read from unmapped memory etc) and implement it.
83 This would enable us to inline allocations and write barriers, for example,
84 or at least parts of them, like the write barrier checks.
85 We may need this also for handling precise info on stacks, even simple things
86 as having uninitialized data on the stack and having to wait for the prolog
87 to zero it. Not an issue for the last frame that we scan conservatively.
88 We could always not trust the value in the slots anyway.
90 *) modify the jit to save info about references in stack locations:
91 this can be done just for locals as a start, so that at least
92 part of the stack is handled precisely.
94 *) test/fix endianess issues
96 *) Implement a card table as the write barrier instead of remembered
97 sets? Card tables are not easy to implement with our current
98 memory layout. We have several different kinds of major heap
99 objects: Small objects in regular blocks, small objects in pinned
100 chunks and LOS objects. If we just have a pointer we have no way
101 to tell which kind of object it points into, therefore we cannot
102 know where its card table is. The least we have to do to make
103 this happen is to get rid of write barriers for indirect stores.
106 *) Get rid of write barriers for indirect stores. We can do this by
107 telling the GC to wbarrier-register an object once we do an ldloca
108 or ldelema on it, and to unregister it once it's not used anymore
109 (it can only travel downwards on the stack). The problem with
110 unregistering is that it needs to happen eventually no matter
111 what, even if exceptions are thrown, the thread aborts, etc.
112 Rodrigo suggested that we could do only the registering part and
113 let the collector find out (pessimistically) when it's safe to
114 unregister, namely when the stack pointer of the thread that
115 registered the object is higher than it was when the registering
116 happened. This might make for a good first implementation to get
117 some data on performance.
119 *) Some sort of blacklist support? Blacklists is a concept from the
120 Boehm GC: if during a conservative scan we find pointers to an
121 area which we might use as heap, we mark that area as unusable, so
122 pointer retention by random pinning pointers is reduced.
124 *) experiment with max small object size (very small right now - 2kb,
125 because it's tied to the max freelist size)
127 *) add an option to mmap the whole heap in one chunk: it makes for many
128 simplifications in the checks (put the nursery at the top and just use a single
129 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
130 not flexible (too much of the address space may be used by default or we can't
131 increase the heap as needed) and we'd need a race-free mechanism to return memory
132 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
133 was written to, munmap is needed, but the following mmap may not find the same segment
136 *) memzero the major fragments after restarting the world and optionally a smaller
139 *) investigate having fragment zeroing threads
141 *) separate locks for finalization and other minor stuff to reduce
144 *) try a different copying order to improve memory locality
146 *) a thread abort after a store but before the write barrier will
147 prevent the write barrier from executing
149 *) specialized dynamically generated markers/copiers
151 *) Dynamically adjust TLAB size to the number of threads. If we have
152 too many threads that do allocation, we might need smaller TLABs,
153 and we might get better performance with larger TLABs if we only
154 have a handful of threads. We could sum up the space left in all
155 assigned TLABs and if that's more than some percentage of the
156 nursery size, reduce the TLAB size.
158 *) Explore placing unreachable objects on unused nursery memory.
159 Instead of memset'ng a region to zero, place an int[] covering it.
160 A good place to start is add_nursery_frag. The tricky thing here is
161 placing those objects atomically outside of a collection.
163 *) Allocation should use asymmetric Dekker synchronization:
164 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
165 This should help weak consistency archs.
172 #define _XOPEN_SOURCE
173 #define _DARWIN_C_SOURCE
179 #ifdef HAVE_PTHREAD_H
182 #ifdef HAVE_PTHREAD_NP_H
183 #include <pthread_np.h>
185 #ifdef HAVE_SEMAPHORE_H
186 #include <semaphore.h>
194 #include "metadata/sgen-gc.h"
195 #include "metadata/metadata-internals.h"
196 #include "metadata/class-internals.h"
197 #include "metadata/gc-internal.h"
198 #include "metadata/object-internals.h"
199 #include "metadata/threads.h"
200 #include "metadata/sgen-cardtable.h"
201 #include "metadata/sgen-protocol.h"
202 #include "metadata/sgen-archdep.h"
203 #include "metadata/sgen-bridge.h"
204 #include "metadata/sgen-memory-governor.h"
205 #include "metadata/sgen-hash-table.h"
206 #include "metadata/mono-gc.h"
207 #include "metadata/method-builder.h"
208 #include "metadata/profiler-private.h"
209 #include "metadata/monitor.h"
210 #include "metadata/mempool-internals.h"
211 #include "metadata/marshal.h"
212 #include "metadata/runtime.h"
213 #include "metadata/sgen-cardtable.h"
214 #include "metadata/sgen-pinning.h"
215 #include "metadata/sgen-workers.h"
216 #include "metadata/sgen-layout-stats.h"
217 #include "utils/mono-mmap.h"
218 #include "utils/mono-time.h"
219 #include "utils/mono-semaphore.h"
220 #include "utils/mono-counters.h"
221 #include "utils/mono-proclib.h"
222 #include "utils/mono-memory-model.h"
223 #include "utils/mono-logger-internal.h"
224 #include "utils/dtrace.h"
226 #include <mono/utils/mono-logger-internal.h>
227 #include <mono/utils/memcheck.h>
229 #if defined(__MACH__)
230 #include "utils/mach-support.h"
233 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
237 #include "mono/cil/opcode.def"
243 #undef pthread_create
245 #undef pthread_detach
248 * ######################################################################
249 * ######## Types and constants used by the GC.
250 * ######################################################################
253 /* 0 means not initialized, 1 is initialized, -1 means in progress */
254 static int gc_initialized = 0;
255 /* If set, check if we need to do something every X allocations */
256 gboolean has_per_allocation_action;
257 /* If set, do a heap check every X allocation */
258 guint32 verify_before_allocs = 0;
259 /* If set, do a minor collection before every X allocation */
260 guint32 collect_before_allocs = 0;
261 /* If set, do a whole heap check before each collection */
262 static gboolean whole_heap_check_before_collection = FALSE;
263 /* If set, do a heap consistency check before each minor collection */
264 static gboolean consistency_check_at_minor_collection = FALSE;
265 /* If set, do a mod union consistency check before each finishing collection pause */
266 static gboolean mod_union_consistency_check = FALSE;
267 /* If set, check whether mark bits are consistent after major collections */
268 static gboolean check_mark_bits_after_major_collection = FALSE;
269 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
270 static gboolean check_nursery_objects_pinned = FALSE;
271 /* If set, do a few checks when the concurrent collector is used */
272 static gboolean do_concurrent_checks = FALSE;
273 /* If set, check that there are no references to the domain left at domain unload */
274 static gboolean xdomain_checks = FALSE;
275 /* If not null, dump the heap after each collection into this file */
276 static FILE *heap_dump_file = NULL;
277 /* If set, mark stacks conservatively, even if precise marking is possible */
278 static gboolean conservative_stack_mark = FALSE;
279 /* If set, do a plausibility check on the scan_starts before and after
281 static gboolean do_scan_starts_check = FALSE;
283 * If the major collector is concurrent and this is FALSE, we will
284 * never initiate a synchronous major collection, unless requested via
287 static gboolean allow_synchronous_major = TRUE;
288 static gboolean disable_minor_collections = FALSE;
289 static gboolean disable_major_collections = FALSE;
290 gboolean do_pin_stats = FALSE;
291 static gboolean do_verify_nursery = FALSE;
292 static gboolean do_dump_nursery_content = FALSE;
293 static gboolean enable_nursery_canaries = FALSE;
295 #ifdef HEAVY_STATISTICS
296 long long stat_objects_alloced_degraded = 0;
297 long long stat_bytes_alloced_degraded = 0;
299 long long stat_copy_object_called_nursery = 0;
300 long long stat_objects_copied_nursery = 0;
301 long long stat_copy_object_called_major = 0;
302 long long stat_objects_copied_major = 0;
304 long long stat_scan_object_called_nursery = 0;
305 long long stat_scan_object_called_major = 0;
307 long long stat_slots_allocated_in_vain;
309 long long stat_nursery_copy_object_failed_from_space = 0;
310 long long stat_nursery_copy_object_failed_forwarded = 0;
311 long long stat_nursery_copy_object_failed_pinned = 0;
312 long long stat_nursery_copy_object_failed_to_space = 0;
314 static int stat_wbarrier_add_to_global_remset = 0;
315 static int stat_wbarrier_set_field = 0;
316 static int stat_wbarrier_set_arrayref = 0;
317 static int stat_wbarrier_arrayref_copy = 0;
318 static int stat_wbarrier_generic_store = 0;
319 static int stat_wbarrier_generic_store_atomic = 0;
320 static int stat_wbarrier_set_root = 0;
321 static int stat_wbarrier_value_copy = 0;
322 static int stat_wbarrier_object_copy = 0;
325 static long long stat_pinned_objects = 0;
327 static long long time_minor_pre_collection_fragment_clear = 0;
328 static long long time_minor_pinning = 0;
329 static long long time_minor_scan_remsets = 0;
330 static long long time_minor_scan_pinned = 0;
331 static long long time_minor_scan_registered_roots = 0;
332 static long long time_minor_scan_thread_data = 0;
333 static long long time_minor_finish_gray_stack = 0;
334 static long long time_minor_fragment_creation = 0;
336 static long long time_major_pre_collection_fragment_clear = 0;
337 static long long time_major_pinning = 0;
338 static long long time_major_scan_pinned = 0;
339 static long long time_major_scan_registered_roots = 0;
340 static long long time_major_scan_thread_data = 0;
341 static long long time_major_scan_alloc_pinned = 0;
342 static long long time_major_scan_finalized = 0;
343 static long long time_major_scan_big_objects = 0;
344 static long long time_major_finish_gray_stack = 0;
345 static long long time_major_free_bigobjs = 0;
346 static long long time_major_los_sweep = 0;
347 static long long time_major_sweep = 0;
348 static long long time_major_fragment_creation = 0;
350 static long long time_max = 0;
352 static SGEN_TV_DECLARE (time_major_conc_collection_start);
353 static SGEN_TV_DECLARE (time_major_conc_collection_end);
355 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
356 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
358 int gc_debug_level = 0;
361 static MonoGCFinalizerCallbacks fin_callbacks;
365 mono_gc_flush_info (void)
367 fflush (gc_debug_file);
371 #define TV_DECLARE SGEN_TV_DECLARE
372 #define TV_GETTIME SGEN_TV_GETTIME
373 #define TV_ELAPSED SGEN_TV_ELAPSED
374 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
376 SGEN_TV_DECLARE (sgen_init_timestamp);
378 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
380 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
382 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
383 #define object_is_pinned SGEN_OBJECT_IS_PINNED
384 #define pin_object SGEN_PIN_OBJECT
385 #define unpin_object SGEN_UNPIN_OBJECT
387 #define ptr_in_nursery sgen_ptr_in_nursery
389 #define LOAD_VTABLE SGEN_LOAD_VTABLE
392 safe_name (void* obj)
394 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
395 return vt->klass->name;
399 nursery_canaries_enabled (void)
401 return enable_nursery_canaries;
404 #define safe_object_get_size sgen_safe_object_get_size
407 sgen_safe_name (void* obj)
409 return safe_name (obj);
413 * ######################################################################
414 * ######## Global data.
415 * ######################################################################
417 LOCK_DECLARE (gc_mutex);
418 gboolean sgen_try_free_some_memory;
420 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
422 static mword pagesize = 4096;
423 size_t degraded_mode = 0;
425 static mword bytes_pinned_from_failed_allocation = 0;
427 GCMemSection *nursery_section = NULL;
428 static volatile mword lowest_heap_address = ~(mword)0;
429 static volatile mword highest_heap_address = 0;
431 LOCK_DECLARE (sgen_interruption_mutex);
432 static LOCK_DECLARE (pin_queue_mutex);
434 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
435 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
437 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
438 struct _FinalizeReadyEntry {
439 FinalizeReadyEntry *next;
443 typedef struct _EphemeronLinkNode EphemeronLinkNode;
445 struct _EphemeronLinkNode {
446 EphemeronLinkNode *next;
455 int current_collection_generation = -1;
456 volatile gboolean concurrent_collection_in_progress = FALSE;
458 /* objects that are ready to be finalized */
459 static FinalizeReadyEntry *fin_ready_list = NULL;
460 static FinalizeReadyEntry *critical_fin_list = NULL;
462 static EphemeronLinkNode *ephemeron_list;
464 /* registered roots: the key to the hash is the root start address */
466 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
468 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
469 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
470 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
471 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
473 static mword roots_size = 0; /* amount of memory in the root set */
475 #define GC_ROOT_NUM 32
477 int count; /* must be the first field */
478 void *objects [GC_ROOT_NUM];
479 int root_types [GC_ROOT_NUM];
480 uintptr_t extra_info [GC_ROOT_NUM];
484 notify_gc_roots (GCRootReport *report)
488 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
493 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
495 if (report->count == GC_ROOT_NUM)
496 notify_gc_roots (report);
497 report->objects [report->count] = object;
498 report->root_types [report->count] = rtype;
499 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
502 MonoNativeTlsKey thread_info_key;
504 #ifdef HAVE_KW_THREAD
505 __thread SgenThreadInfo *sgen_thread_info;
506 __thread char *stack_end;
509 /* The size of a TLAB */
510 /* The bigger the value, the less often we have to go to the slow path to allocate a new
511 * one, but the more space is wasted by threads not allocating much memory.
513 * FIXME: Make this self-tuning for each thread.
515 guint32 tlab_size = (1024 * 4);
517 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
519 /* Functions supplied by the runtime to be called by the GC */
520 static MonoGCCallbacks gc_callbacks;
522 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
523 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
525 #define ALIGN_UP SGEN_ALIGN_UP
527 #define MOVED_OBJECTS_NUM 64
528 static void *moved_objects [MOVED_OBJECTS_NUM];
529 static int moved_objects_idx = 0;
531 /* Vtable of the objects used to fill out nursery fragments before a collection */
532 static MonoVTable *array_fill_vtable;
534 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
535 MonoNativeThreadId main_gc_thread = NULL;
538 /*Object was pinned during the current collection*/
539 static mword objects_pinned;
542 * ######################################################################
543 * ######## Macros and function declarations.
544 * ######################################################################
548 align_pointer (void *ptr)
550 mword p = (mword)ptr;
551 p += sizeof (gpointer) - 1;
552 p &= ~ (sizeof (gpointer) - 1);
556 typedef SgenGrayQueue GrayQueue;
558 /* forward declarations */
559 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
560 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
561 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
562 static void report_finalizer_roots (void);
563 static void report_registered_roots (void);
565 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
566 static void finish_gray_stack (int generation, GrayQueue *queue);
568 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
571 static void init_stats (void);
573 static int mark_ephemerons_in_range (ScanCopyContext ctx);
574 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
575 static void null_ephemerons_for_domain (MonoDomain *domain);
577 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
579 SgenObjectOperations current_object_ops;
580 SgenMajorCollector major_collector;
581 SgenMinorCollector sgen_minor_collector;
582 static GrayQueue gray_queue;
584 static SgenRemeberedSet remset;
586 /* The gray queue to use from the main collection thread. */
587 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
590 * The gray queue a worker job must use. If we're not parallel or
591 * concurrent, we use the main gray queue.
593 static SgenGrayQueue*
594 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
596 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
600 gray_queue_redirect (SgenGrayQueue *queue)
602 gboolean wake = FALSE;
605 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
608 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
613 g_assert (concurrent_collection_in_progress);
614 if (sgen_workers_have_started ()) {
615 sgen_workers_ensure_awake ();
617 if (concurrent_collection_in_progress)
618 g_assert (current_collection_generation == -1);
624 gray_queue_enable_redirect (SgenGrayQueue *queue)
626 if (!concurrent_collection_in_progress)
629 sgen_gray_queue_set_alloc_prepare (queue, gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
630 gray_queue_redirect (queue);
634 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
636 while (start < end) {
640 if (!*(void**)start) {
641 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
646 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
652 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
653 CHECK_CANARY_FOR_OBJECT (obj);
654 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
655 callback (obj, size, data);
656 CANARIFY_SIZE (size);
658 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
666 need_remove_object_for_domain (char *start, MonoDomain *domain)
668 if (mono_object_domain (start) == domain) {
669 SGEN_LOG (4, "Need to cleanup object %p", start);
670 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
677 process_object_for_domain_clearing (char *start, MonoDomain *domain)
679 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
680 if (vt->klass == mono_defaults.internal_thread_class)
681 g_assert (mono_object_domain (start) == mono_get_root_domain ());
682 /* The object could be a proxy for an object in the domain
684 #ifndef DISABLE_REMOTING
685 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
686 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
688 /* The server could already have been zeroed out, so
689 we need to check for that, too. */
690 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
691 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
692 ((MonoRealProxy*)start)->unwrapped_server = NULL;
699 clear_domain_process_object (char *obj, MonoDomain *domain)
703 process_object_for_domain_clearing (obj, domain);
704 remove = need_remove_object_for_domain (obj, domain);
706 if (remove && ((MonoObject*)obj)->synchronisation) {
707 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
709 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
716 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
718 if (clear_domain_process_object (obj, domain)) {
719 CANARIFY_SIZE (size);
720 memset (obj, 0, size);
725 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
727 clear_domain_process_object (obj, domain);
731 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
733 if (need_remove_object_for_domain (obj, domain))
734 major_collector.free_non_pinned_object (obj, size);
738 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
740 if (need_remove_object_for_domain (obj, domain))
741 major_collector.free_pinned_object (obj, size);
745 * When appdomains are unloaded we can easily remove objects that have finalizers,
746 * but all the others could still be present in random places on the heap.
747 * We need a sweep to get rid of them even though it's going to be costly
749 * The reason we need to remove them is because we access the vtable and class
750 * structures to know the object size and the reference bitmap: once the domain is
751 * unloaded the point to random memory.
754 mono_gc_clear_domain (MonoDomain * domain)
756 LOSObject *bigobj, *prev;
761 binary_protocol_domain_unload_begin (domain);
765 if (concurrent_collection_in_progress)
766 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
767 g_assert (!concurrent_collection_in_progress);
769 sgen_process_fin_stage_entries ();
770 sgen_process_dislink_stage_entries ();
772 sgen_clear_nursery_fragments ();
774 if (xdomain_checks && domain != mono_get_root_domain ()) {
775 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
776 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
777 sgen_check_for_xdomain_refs ();
780 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
781 to memory returned to the OS.*/
782 null_ephemerons_for_domain (domain);
784 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
785 sgen_null_links_for_domain (domain, i);
787 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
788 sgen_remove_finalizers_for_domain (domain, i);
790 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
791 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
793 /* We need two passes over major and large objects because
794 freeing such objects might give their memory back to the OS
795 (in the case of large objects) or obliterate its vtable
796 (pinned objects with major-copying or pinned and non-pinned
797 objects with major-mark&sweep), but we might need to
798 dereference a pointer from an object to another object if
799 the first object is a proxy. */
800 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
801 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
802 clear_domain_process_object (bigobj->data, domain);
805 for (bigobj = los_object_list; bigobj;) {
806 if (need_remove_object_for_domain (bigobj->data, domain)) {
807 LOSObject *to_free = bigobj;
809 prev->next = bigobj->next;
811 los_object_list = bigobj->next;
812 bigobj = bigobj->next;
813 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
814 sgen_los_free_object (to_free);
818 bigobj = bigobj->next;
820 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
821 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
823 if (domain == mono_get_root_domain ()) {
824 if (G_UNLIKELY (do_pin_stats))
825 sgen_pin_stats_print_class_stats ();
826 sgen_object_layout_dump (stdout);
829 sgen_restart_world (0, NULL);
831 binary_protocol_domain_unload_end (domain);
837 * sgen_add_to_global_remset:
839 * The global remset contains locations which point into newspace after
840 * a minor collection. This can happen if the objects they point to are pinned.
842 * LOCKING: If called from a parallel collector, the global remset
843 * lock must be held. For serial collectors that is not necessary.
846 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
848 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
850 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
852 if (!major_collector.is_concurrent) {
853 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
855 if (current_collection_generation == -1)
856 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
859 if (!object_is_pinned (obj))
860 SGEN_ASSERT (5, sgen_minor_collector.is_split || sgen_concurrent_collection_in_progress (), "Non-pinned objects can only remain in nursery if it is a split nursery");
861 else if (sgen_cement_lookup_or_register (obj))
864 remset.record_pointer (ptr);
866 if (G_UNLIKELY (do_pin_stats))
867 sgen_pin_stats_register_global_remset (obj);
869 SGEN_LOG (8, "Adding global remset for %p", ptr);
870 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
874 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
875 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
876 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
877 vt->klass->name_space, vt->klass->name);
883 * sgen_drain_gray_stack:
885 * Scan objects in the gray stack until the stack is empty. This should be called
886 * frequently after each object is copied, to achieve better locality and cache
889 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
893 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
895 ScanObjectFunc scan_func = ctx.scan_func;
896 GrayQueue *queue = ctx.queue;
900 for (i = 0; i != max_objs; ++i) {
903 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
906 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
907 scan_func (obj, desc, queue);
909 } while (max_objs < 0);
914 * Addresses in the pin queue are already sorted. This function finds
915 * the object header for each address and pins the object. The
916 * addresses must be inside the nursery section. The (start of the)
917 * address array is overwritten with the addresses of the actually
918 * pinned objects. Return the number of pinned objects.
921 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
923 GCMemSection *section = nursery_section;
924 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
925 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
926 void *start_nursery = section->data;
927 void *end_nursery = section->next_data;
932 void *pinning_front = start_nursery;
934 void **definitely_pinned = start;
935 ScanObjectFunc scan_func = ctx.scan_func;
936 SgenGrayQueue *queue = ctx.queue;
938 sgen_nursery_allocator_prepare_for_pinning ();
940 while (start < end) {
941 void *obj_to_pin = NULL;
942 size_t obj_to_pin_size = 0;
947 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
948 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
955 SGEN_LOG (5, "Considering pinning addr %p", addr);
956 /* We've already processed everything up to pinning_front. */
957 if (addr < pinning_front) {
963 * Find the closest scan start <= addr. We might search backward in the
964 * scan_starts array because entries might be NULL. In the worst case we
965 * start at start_nursery.
967 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
968 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
969 search_start = (void*)section->scan_starts [idx];
970 if (!search_start || search_start > addr) {
973 search_start = section->scan_starts [idx];
974 if (search_start && search_start <= addr)
977 if (!search_start || search_start > addr)
978 search_start = start_nursery;
982 * If the pinning front is closer than the scan start we found, start
983 * searching at the front.
985 if (search_start < pinning_front)
986 search_start = pinning_front;
989 * Now addr should be in an object a short distance from search_start.
991 * search_start must point to zeroed mem or point to an object.
997 if (!*(void**)search_start) {
998 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
999 /* The loop condition makes sure we don't overrun addr. */
1003 obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1005 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
1006 /* This is the object we're looking for. */
1007 obj_to_pin = search_start;
1008 obj_to_pin_size = obj_size;
1012 /* Skip to the next object */
1013 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
1014 CHECK_CANARY_FOR_OBJECT (search_start);
1015 CANARIFY_SIZE (obj_size);
1016 CANARIFY_SIZE (obj_to_pin_size);
1018 search_start = (void*)((char*)search_start + obj_size);
1019 } while (search_start <= addr);
1021 /* We've searched past the address we were looking for. */
1023 pinning_front = search_start;
1024 goto next_pin_queue_entry;
1028 * We've found an object to pin. It might still be a dummy array, but we
1029 * can advance the pinning front in any case.
1031 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1034 * If this is a dummy array marking the beginning of a nursery
1035 * fragment, we don't pin it.
1037 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1038 goto next_pin_queue_entry;
1041 * Finally - pin the object!
1043 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1045 scan_func (obj_to_pin, desc, queue);
1047 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1048 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1049 binary_protocol_pin (obj_to_pin,
1050 (gpointer)LOAD_VTABLE (obj_to_pin),
1051 safe_object_get_size (obj_to_pin));
1053 #ifdef ENABLE_DTRACE
1054 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1055 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1056 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1057 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1058 sgen_safe_object_get_size (obj_to_pin),
1059 vt->klass->name_space, vt->klass->name, gen);
1063 pin_object (obj_to_pin);
1064 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1065 if (G_UNLIKELY (do_pin_stats))
1066 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1067 definitely_pinned [count] = obj_to_pin;
1071 next_pin_queue_entry:
1075 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1076 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1077 GCRootReport report;
1079 for (idx = 0; idx < count; ++idx)
1080 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1081 notify_gc_roots (&report);
1083 stat_pinned_objects += count;
1088 pin_objects_in_nursery (ScanCopyContext ctx)
1092 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
1095 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1096 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
1101 sgen_pin_object (void *object, GrayQueue *queue)
1103 SGEN_PIN_OBJECT (object);
1104 sgen_pin_stage_ptr (object);
1106 if (G_UNLIKELY (do_pin_stats))
1107 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1109 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1110 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1112 #ifdef ENABLE_DTRACE
1113 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1114 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1115 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1116 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1122 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1126 gboolean major_pinned = FALSE;
1128 if (sgen_ptr_in_nursery (obj)) {
1129 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1130 sgen_pin_object (obj, queue);
1134 major_collector.pin_major_object (obj, queue);
1135 major_pinned = TRUE;
1138 vtable_word = *(mword*)obj;
1139 /*someone else forwarded it, update the pointer and bail out*/
1140 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1141 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1145 /*someone pinned it, nothing to do.*/
1146 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1151 /* Sort the addresses in array in increasing order.
1152 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1155 sgen_sort_addresses (void **array, size_t size)
1160 for (i = 1; i < size; ++i) {
1163 size_t parent = (child - 1) / 2;
1165 if (array [parent] >= array [child])
1168 tmp = array [parent];
1169 array [parent] = array [child];
1170 array [child] = tmp;
1176 for (i = size - 1; i > 0; --i) {
1179 array [i] = array [0];
1185 while (root * 2 + 1 <= end) {
1186 size_t child = root * 2 + 1;
1188 if (child < end && array [child] < array [child + 1])
1190 if (array [root] >= array [child])
1194 array [root] = array [child];
1195 array [child] = tmp;
1203 * Scan the memory between start and end and queue values which could be pointers
1204 * to the area between start_nursery and end_nursery for later consideration.
1205 * Typically used for thread stacks.
1208 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1212 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1213 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1216 while (start < end) {
1217 if (*start >= start_nursery && *start < end_nursery) {
1219 * *start can point to the middle of an object
1220 * note: should we handle pointing at the end of an object?
1221 * pinning in C# code disallows pointing at the end of an object
1222 * but there is some small chance that an optimizing C compiler
1223 * may keep the only reference to an object by pointing
1224 * at the end of it. We ignore this small chance for now.
1225 * Pointers to the end of an object are indistinguishable
1226 * from pointers to the start of the next object in memory
1227 * so if we allow that we'd need to pin two objects...
1228 * We queue the pointer in an array, the
1229 * array will then be sorted and uniqued. This way
1230 * we can coalesce several pinning pointers and it should
1231 * be faster since we'd do a memory scan with increasing
1232 * addresses. Note: we can align the address to the allocation
1233 * alignment, so the unique process is more effective.
1235 mword addr = (mword)*start;
1236 addr &= ~(ALLOC_ALIGN - 1);
1237 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1238 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1239 sgen_pin_stage_ptr ((void*)addr);
1240 binary_protocol_pin_stage (start, (void*)addr);
1243 if (G_UNLIKELY (do_pin_stats)) {
1244 if (ptr_in_nursery ((void*)addr))
1245 sgen_pin_stats_register_address ((char*)addr, pin_type);
1251 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1255 * The first thing we do in a collection is to identify pinned objects.
1256 * This function considers all the areas of memory that need to be
1257 * conservatively scanned.
1260 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1264 SGEN_LOG (2, "Scanning pinned roots (%d bytes, %d/%d entries)", (int)roots_size, roots_hash [ROOT_TYPE_NORMAL].num_entries, roots_hash [ROOT_TYPE_PINNED].num_entries);
1265 /* objects pinned from the API are inside these roots */
1266 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1267 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1268 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1269 } SGEN_HASH_TABLE_FOREACH_END;
1270 /* now deal with the thread stacks
1271 * in the future we should be able to conservatively scan only:
1272 * *) the cpu registers
1273 * *) the unmanaged stack frames
1274 * *) the _last_ managed stack frame
1275 * *) pointers slots in managed frames
1277 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1281 unpin_objects_from_queue (SgenGrayQueue *queue)
1286 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1289 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1290 SGEN_UNPIN_OBJECT (addr);
1295 CopyOrMarkObjectFunc func;
1297 } UserCopyOrMarkData;
1300 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1302 UserCopyOrMarkData *data = gc_data;
1304 data->func (obj, data->queue);
1308 * The memory area from start_root to end_root contains pointers to objects.
1309 * Their position is precisely described by @desc (this means that the pointer
1310 * can be either NULL or the pointer to the start of an object).
1311 * This functions copies them to to_space updates them.
1313 * This function is not thread-safe!
1316 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1318 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1319 SgenGrayQueue *queue = ctx.queue;
1321 switch (desc & ROOT_DESC_TYPE_MASK) {
1322 case ROOT_DESC_BITMAP:
1323 desc >>= ROOT_DESC_TYPE_SHIFT;
1325 if ((desc & 1) && *start_root) {
1326 copy_func (start_root, queue);
1327 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1328 sgen_drain_gray_stack (-1, ctx);
1334 case ROOT_DESC_COMPLEX: {
1335 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1336 gsize bwords = (*bitmap_data) - 1;
1337 void **start_run = start_root;
1339 while (bwords-- > 0) {
1340 gsize bmap = *bitmap_data++;
1341 void **objptr = start_run;
1343 if ((bmap & 1) && *objptr) {
1344 copy_func (objptr, queue);
1345 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1346 sgen_drain_gray_stack (-1, ctx);
1351 start_run += GC_BITS_PER_WORD;
1355 case ROOT_DESC_USER: {
1356 UserCopyOrMarkData data = { copy_func, queue };
1357 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1358 marker (start_root, single_arg_user_copy_or_mark, &data);
1361 case ROOT_DESC_RUN_LEN:
1362 g_assert_not_reached ();
1364 g_assert_not_reached ();
1369 reset_heap_boundaries (void)
1371 lowest_heap_address = ~(mword)0;
1372 highest_heap_address = 0;
1376 sgen_update_heap_boundaries (mword low, mword high)
1381 old = lowest_heap_address;
1384 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1387 old = highest_heap_address;
1390 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1394 * Allocate and setup the data structures needed to be able to allocate objects
1395 * in the nursery. The nursery is stored in nursery_section.
1398 alloc_nursery (void)
1400 GCMemSection *section;
1405 if (nursery_section)
1407 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1408 /* later we will alloc a larger area for the nursery but only activate
1409 * what we need. The rest will be used as expansion if we have too many pinned
1410 * objects in the existing nursery.
1412 /* FIXME: handle OOM */
1413 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1415 alloc_size = sgen_nursery_size;
1417 /* If there isn't enough space even for the nursery we should simply abort. */
1418 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1420 #ifdef SGEN_ALIGN_NURSERY
1421 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1423 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1425 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1426 SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)mono_gc_get_heap_size ());
1427 section->data = section->next_data = data;
1428 section->size = alloc_size;
1429 section->end_data = data + sgen_nursery_size;
1430 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1431 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1432 section->num_scan_start = scan_starts;
1434 nursery_section = section;
1436 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1440 mono_gc_get_nursery (int *shift_bits, size_t *size)
1442 *size = sgen_nursery_size;
1443 #ifdef SGEN_ALIGN_NURSERY
1444 *shift_bits = DEFAULT_NURSERY_BITS;
1448 return sgen_get_nursery_start ();
1452 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1454 SgenThreadInfo *info = mono_thread_info_current ();
1456 /* Could be called from sgen_thread_unregister () with a NULL info */
1459 info->stopped_domain = domain;
1464 mono_gc_precise_stack_mark_enabled (void)
1466 return !conservative_stack_mark;
1470 mono_gc_get_logfile (void)
1472 return gc_debug_file;
1476 report_finalizer_roots_list (FinalizeReadyEntry *list)
1478 GCRootReport report;
1479 FinalizeReadyEntry *fin;
1482 for (fin = list; fin; fin = fin->next) {
1485 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1487 notify_gc_roots (&report);
1491 report_finalizer_roots (void)
1493 report_finalizer_roots_list (fin_ready_list);
1494 report_finalizer_roots_list (critical_fin_list);
1497 static GCRootReport *root_report;
1500 single_arg_report_root (void **obj, void *gc_data)
1503 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1507 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1509 switch (desc & ROOT_DESC_TYPE_MASK) {
1510 case ROOT_DESC_BITMAP:
1511 desc >>= ROOT_DESC_TYPE_SHIFT;
1513 if ((desc & 1) && *start_root) {
1514 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1520 case ROOT_DESC_COMPLEX: {
1521 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1522 gsize bwords = (*bitmap_data) - 1;
1523 void **start_run = start_root;
1525 while (bwords-- > 0) {
1526 gsize bmap = *bitmap_data++;
1527 void **objptr = start_run;
1529 if ((bmap & 1) && *objptr) {
1530 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1535 start_run += GC_BITS_PER_WORD;
1539 case ROOT_DESC_USER: {
1540 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1541 root_report = report;
1542 marker (start_root, single_arg_report_root, NULL);
1545 case ROOT_DESC_RUN_LEN:
1546 g_assert_not_reached ();
1548 g_assert_not_reached ();
1553 report_registered_roots_by_type (int root_type)
1555 GCRootReport report;
1559 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1560 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1561 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1562 } SGEN_HASH_TABLE_FOREACH_END;
1563 notify_gc_roots (&report);
1567 report_registered_roots (void)
1569 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1570 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1574 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1576 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1577 SgenGrayQueue *queue = ctx.queue;
1578 FinalizeReadyEntry *fin;
1580 for (fin = list; fin; fin = fin->next) {
1583 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1584 copy_func (&fin->object, queue);
1589 generation_name (int generation)
1591 switch (generation) {
1592 case GENERATION_NURSERY: return "nursery";
1593 case GENERATION_OLD: return "old";
1594 default: g_assert_not_reached ();
1599 sgen_generation_name (int generation)
1601 return generation_name (generation);
1604 SgenObjectOperations *
1605 sgen_get_current_object_ops (void){
1606 return ¤t_object_ops;
1611 finish_gray_stack (int generation, GrayQueue *queue)
1615 int done_with_ephemerons, ephemeron_rounds = 0;
1616 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1617 ScanObjectFunc scan_func = current_object_ops.scan_object;
1618 ScanCopyContext ctx = { scan_func, copy_func, queue };
1619 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1620 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1623 * We copied all the reachable objects. Now it's the time to copy
1624 * the objects that were not referenced by the roots, but by the copied objects.
1625 * we built a stack of objects pointed to by gray_start: they are
1626 * additional roots and we may add more items as we go.
1627 * We loop until gray_start == gray_objects which means no more objects have
1628 * been added. Note this is iterative: no recursion is involved.
1629 * We need to walk the LO list as well in search of marked big objects
1630 * (use a flag since this is needed only on major collections). We need to loop
1631 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1632 * To achieve better cache locality and cache usage, we drain the gray stack
1633 * frequently, after each object is copied, and just finish the work here.
1635 sgen_drain_gray_stack (-1, ctx);
1637 SGEN_LOG (2, "%s generation done", generation_name (generation));
1640 Reset bridge data, we might have lingering data from a previous collection if this is a major
1641 collection trigged by minor overflow.
1643 We must reset the gathered bridges since their original block might be evacuated due to major
1644 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1646 if (sgen_need_bridge_processing ())
1647 sgen_bridge_reset_data ();
1650 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1651 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1652 * objects that are in fact reachable.
1654 done_with_ephemerons = 0;
1656 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1657 sgen_drain_gray_stack (-1, ctx);
1659 } while (!done_with_ephemerons);
1661 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1663 if (sgen_need_bridge_processing ()) {
1664 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1665 sgen_drain_gray_stack (-1, ctx);
1666 sgen_collect_bridge_objects (generation, ctx);
1667 if (generation == GENERATION_OLD)
1668 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1671 Do the first bridge step here, as the collector liveness state will become useless after that.
1673 An important optimization is to only proccess the possibly dead part of the object graph and skip
1674 over all live objects as we transitively know everything they point must be alive too.
1676 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1678 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1679 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1682 sgen_bridge_processing_stw_step ();
1686 Make sure we drain the gray stack before processing disappearing links and finalizers.
1687 If we don't make sure it is empty we might wrongly see a live object as dead.
1689 sgen_drain_gray_stack (-1, ctx);
1692 We must clear weak links that don't track resurrection before processing object ready for
1693 finalization so they can be cleared before that.
1695 sgen_null_link_in_range (generation, TRUE, ctx);
1696 if (generation == GENERATION_OLD)
1697 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1700 /* walk the finalization queue and move also the objects that need to be
1701 * finalized: use the finalized objects as new roots so the objects they depend
1702 * on are also not reclaimed. As with the roots above, only objects in the nursery
1703 * are marked/copied.
1705 sgen_finalize_in_range (generation, ctx);
1706 if (generation == GENERATION_OLD)
1707 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1708 /* drain the new stack that might have been created */
1709 SGEN_LOG (6, "Precise scan of gray area post fin");
1710 sgen_drain_gray_stack (-1, ctx);
1713 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1715 done_with_ephemerons = 0;
1717 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1718 sgen_drain_gray_stack (-1, ctx);
1720 } while (!done_with_ephemerons);
1723 * Clear ephemeron pairs with unreachable keys.
1724 * We pass the copy func so we can figure out if an array was promoted or not.
1726 clear_unreachable_ephemerons (ctx);
1729 * We clear togglerefs only after all possible chances of revival are done.
1730 * This is semantically more inline with what users expect and it allows for
1731 * user finalizers to correctly interact with TR objects.
1733 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1736 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1739 * handle disappearing links
1740 * Note we do this after checking the finalization queue because if an object
1741 * survives (at least long enough to be finalized) we don't clear the link.
1742 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1743 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1746 g_assert (sgen_gray_object_queue_is_empty (queue));
1748 sgen_null_link_in_range (generation, FALSE, ctx);
1749 if (generation == GENERATION_OLD)
1750 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1751 if (sgen_gray_object_queue_is_empty (queue))
1753 sgen_drain_gray_stack (-1, ctx);
1756 g_assert (sgen_gray_object_queue_is_empty (queue));
1758 sgen_gray_object_queue_trim_free_list (queue);
1762 sgen_check_section_scan_starts (GCMemSection *section)
1765 for (i = 0; i < section->num_scan_start; ++i) {
1766 if (section->scan_starts [i]) {
1767 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1768 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1774 check_scan_starts (void)
1776 if (!do_scan_starts_check)
1778 sgen_check_section_scan_starts (nursery_section);
1779 major_collector.check_scan_starts ();
1783 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1787 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1788 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1789 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1790 } SGEN_HASH_TABLE_FOREACH_END;
1794 sgen_dump_occupied (char *start, char *end, char *section_start)
1796 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1800 sgen_dump_section (GCMemSection *section, const char *type)
1802 char *start = section->data;
1803 char *end = section->data + section->size;
1804 char *occ_start = NULL;
1806 char *old_start = NULL; /* just for debugging */
1808 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1810 while (start < end) {
1814 if (!*(void**)start) {
1816 sgen_dump_occupied (occ_start, start, section->data);
1819 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1822 g_assert (start < section->next_data);
1827 vt = (GCVTable*)LOAD_VTABLE (start);
1830 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1833 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1834 start - section->data,
1835 vt->klass->name_space, vt->klass->name,
1843 sgen_dump_occupied (occ_start, start, section->data);
1845 fprintf (heap_dump_file, "</section>\n");
1849 dump_object (MonoObject *obj, gboolean dump_location)
1851 static char class_name [1024];
1853 MonoClass *class = mono_object_class (obj);
1857 * Python's XML parser is too stupid to parse angle brackets
1858 * in strings, so we just ignore them;
1861 while (class->name [i] && j < sizeof (class_name) - 1) {
1862 if (!strchr ("<>\"", class->name [i]))
1863 class_name [j++] = class->name [i];
1866 g_assert (j < sizeof (class_name));
1869 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1870 class->name_space, class_name,
1871 safe_object_get_size (obj));
1872 if (dump_location) {
1873 const char *location;
1874 if (ptr_in_nursery (obj))
1875 location = "nursery";
1876 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1880 fprintf (heap_dump_file, " location=\"%s\"", location);
1882 fprintf (heap_dump_file, "/>\n");
1886 dump_heap (const char *type, int num, const char *reason)
1891 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1893 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1894 fprintf (heap_dump_file, ">\n");
1895 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1896 sgen_dump_internal_mem_usage (heap_dump_file);
1897 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1898 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1899 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1901 fprintf (heap_dump_file, "<pinned-objects>\n");
1902 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1903 dump_object (list->obj, TRUE);
1904 fprintf (heap_dump_file, "</pinned-objects>\n");
1906 sgen_dump_section (nursery_section, "nursery");
1908 major_collector.dump_heap (heap_dump_file);
1910 fprintf (heap_dump_file, "<los>\n");
1911 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1912 dump_object ((MonoObject*)bigobj->data, FALSE);
1913 fprintf (heap_dump_file, "</los>\n");
1915 fprintf (heap_dump_file, "</collection>\n");
1919 sgen_register_moved_object (void *obj, void *destination)
1921 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1923 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1924 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1925 moved_objects_idx = 0;
1927 moved_objects [moved_objects_idx++] = obj;
1928 moved_objects [moved_objects_idx++] = destination;
1934 static gboolean inited = FALSE;
1939 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1941 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1942 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pinning);
1943 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1944 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1945 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1946 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1947 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1948 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1950 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1951 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pinning);
1952 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1953 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1954 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1955 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1956 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1957 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1958 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1959 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1960 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1961 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_sweep);
1962 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1964 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
1966 #ifdef HEAVY_STATISTICS
1967 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1968 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1969 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1970 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1971 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1972 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1973 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1974 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1975 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1977 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
1978 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
1980 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
1981 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
1982 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
1983 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
1985 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
1986 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
1988 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
1990 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
1991 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
1992 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
1993 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
1995 sgen_nursery_allocator_init_heavy_stats ();
1996 sgen_alloc_init_heavy_stats ();
2004 reset_pinned_from_failed_allocation (void)
2006 bytes_pinned_from_failed_allocation = 0;
2010 sgen_set_pinned_from_failed_allocation (mword objsize)
2012 bytes_pinned_from_failed_allocation += objsize;
2016 sgen_collection_is_concurrent (void)
2018 switch (current_collection_generation) {
2019 case GENERATION_NURSERY:
2021 case GENERATION_OLD:
2022 return concurrent_collection_in_progress;
2024 g_error ("Invalid current generation %d", current_collection_generation);
2029 sgen_concurrent_collection_in_progress (void)
2031 return concurrent_collection_in_progress;
2038 } FinishRememberedSetScanJobData;
2041 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2043 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2045 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2046 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2051 CopyOrMarkObjectFunc copy_or_mark_func;
2052 ScanObjectFunc scan_func;
2056 } ScanFromRegisteredRootsJobData;
2059 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2061 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2062 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2063 sgen_workers_get_job_gray_queue (worker_data) };
2065 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2066 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2073 } ScanThreadDataJobData;
2076 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2078 ScanThreadDataJobData *job_data = job_data_untyped;
2080 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2081 sgen_workers_get_job_gray_queue (worker_data));
2082 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2086 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2088 FinalizeReadyEntry *list = job_data_untyped;
2089 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2091 scan_finalizer_entries (list, ctx);
2095 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2097 g_assert (concurrent_collection_in_progress);
2098 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2102 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2104 g_assert (concurrent_collection_in_progress);
2105 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2109 verify_scan_starts (char *start, char *end)
2113 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2114 char *addr = nursery_section->scan_starts [i];
2115 if (addr > start && addr < end)
2116 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2121 verify_nursery (void)
2123 char *start, *end, *cur, *hole_start;
2125 if (!do_verify_nursery)
2128 if (nursery_canaries_enabled ())
2129 SGEN_LOG (1, "Checking nursery canaries...");
2131 /*This cleans up unused fragments */
2132 sgen_nursery_allocator_prepare_for_pinning ();
2134 hole_start = start = cur = sgen_get_nursery_start ();
2135 end = sgen_get_nursery_end ();
2140 if (!*(void**)cur) {
2141 cur += sizeof (void*);
2145 if (object_is_forwarded (cur))
2146 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2147 else if (object_is_pinned (cur))
2148 SGEN_LOG (1, "PINNED OBJ %p", cur);
2150 ss = safe_object_get_size ((MonoObject*)cur);
2151 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2152 verify_scan_starts (cur, cur + size);
2153 if (do_dump_nursery_content) {
2154 if (cur > hole_start)
2155 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2156 SGEN_LOG (1, "OBJ [%p %p %d %d %s %d]", cur, cur + size, (int)size, (int)ss, sgen_safe_name ((MonoObject*)cur), (gpointer)LOAD_VTABLE (cur) == sgen_get_array_fill_vtable ());
2158 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2159 CHECK_CANARY_FOR_OBJECT (cur);
2160 CANARIFY_SIZE (size);
2168 * Checks that no objects in the nursery are fowarded or pinned. This
2169 * is a precondition to restarting the mutator while doing a
2170 * concurrent collection. Note that we don't clear fragments because
2171 * we depend on that having happened earlier.
2174 check_nursery_is_clean (void)
2176 char *start, *end, *cur;
2178 start = cur = sgen_get_nursery_start ();
2179 end = sgen_get_nursery_end ();
2184 if (!*(void**)cur) {
2185 cur += sizeof (void*);
2189 g_assert (!object_is_forwarded (cur));
2190 g_assert (!object_is_pinned (cur));
2192 ss = safe_object_get_size ((MonoObject*)cur);
2193 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2194 verify_scan_starts (cur, cur + size);
2201 init_gray_queue (void)
2203 if (sgen_collection_is_concurrent ())
2204 sgen_workers_init_distribute_gray_queue ();
2205 sgen_gray_object_queue_init (&gray_queue, NULL);
2209 * Perform a nursery collection.
2211 * Return whether any objects were late-pinned due to being out of memory.
2214 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2216 gboolean needs_major;
2217 size_t max_garbage_amount;
2219 FinishRememberedSetScanJobData *frssjd;
2220 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2221 ScanThreadDataJobData *stdjd;
2222 mword fragment_total;
2223 ScanCopyContext ctx;
2227 if (disable_minor_collections)
2230 TV_GETTIME (last_minor_collection_start_tv);
2231 atv = last_minor_collection_start_tv;
2233 MONO_GC_BEGIN (GENERATION_NURSERY);
2234 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2238 #ifndef DISABLE_PERFCOUNTERS
2239 mono_perfcounters->gc_collections0++;
2242 current_collection_generation = GENERATION_NURSERY;
2243 current_object_ops = sgen_minor_collector.serial_ops;
2245 reset_pinned_from_failed_allocation ();
2247 check_scan_starts ();
2249 sgen_nursery_alloc_prepare_for_minor ();
2253 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2254 /* FIXME: optimize later to use the higher address where an object can be present */
2255 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2257 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", gc_stats.minor_gc_count, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ()));
2258 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2259 g_assert (nursery_section->size >= max_garbage_amount);
2261 /* world must be stopped already */
2263 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2265 if (xdomain_checks) {
2266 sgen_clear_nursery_fragments ();
2267 sgen_check_for_xdomain_refs ();
2270 nursery_section->next_data = nursery_next;
2272 major_collector.start_nursery_collection ();
2274 sgen_memgov_minor_collection_start ();
2278 gc_stats.minor_gc_count ++;
2280 if (whole_heap_check_before_collection) {
2281 sgen_clear_nursery_fragments ();
2282 sgen_check_whole_heap (finish_up_concurrent_mark);
2284 if (consistency_check_at_minor_collection)
2285 sgen_check_consistency ();
2287 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2289 sgen_process_fin_stage_entries ();
2290 sgen_process_dislink_stage_entries ();
2292 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2294 /* pin from pinned handles */
2295 sgen_init_pinning ();
2296 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2297 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2298 /* pin cemented objects */
2299 sgen_pin_cemented_objects ();
2300 /* identify pinned objects */
2301 sgen_optimize_pin_queue ();
2302 sgen_pinning_setup_section (nursery_section);
2303 ctx.scan_func = NULL;
2304 ctx.copy_func = NULL;
2305 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2306 pin_objects_in_nursery (ctx);
2307 sgen_pinning_trim_queue_to_section (nursery_section);
2310 time_minor_pinning += TV_ELAPSED (btv, atv);
2311 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2312 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2314 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2316 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2317 frssjd->heap_start = sgen_get_nursery_start ();
2318 frssjd->heap_end = nursery_next;
2319 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2321 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2323 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2324 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2326 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2328 /* FIXME: why is this here? */
2329 ctx.scan_func = current_object_ops.scan_object;
2330 ctx.copy_func = NULL;
2331 ctx.queue = &gray_queue;
2332 sgen_drain_gray_stack (-1, ctx);
2334 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2335 report_registered_roots ();
2336 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2337 report_finalizer_roots ();
2339 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2341 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2343 /* registered roots, this includes static fields */
2344 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2345 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2346 scrrjd_normal->scan_func = current_object_ops.scan_object;
2347 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2348 scrrjd_normal->heap_end = nursery_next;
2349 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2350 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2352 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2353 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2354 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2355 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2356 scrrjd_wbarrier->heap_end = nursery_next;
2357 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2358 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2361 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2363 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2366 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2367 stdjd->heap_start = sgen_get_nursery_start ();
2368 stdjd->heap_end = nursery_next;
2369 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2372 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2375 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2377 g_assert (!sgen_collection_is_concurrent ());
2379 /* Scan the list of objects ready for finalization. If */
2380 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2381 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2383 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2385 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2387 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2388 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2390 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2393 * The (single-threaded) finalization code might have done
2394 * some copying/marking so we can only reset the GC thread's
2395 * worker data here instead of earlier when we joined the
2398 sgen_workers_reset_data ();
2400 if (objects_pinned) {
2401 sgen_optimize_pin_queue ();
2402 sgen_pinning_setup_section (nursery_section);
2405 /* walk the pin_queue, build up the fragment list of free memory, unmark
2406 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2409 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2410 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2411 if (!fragment_total)
2414 /* Clear TLABs for all threads */
2415 sgen_clear_tlabs ();
2417 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2419 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2420 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2422 if (consistency_check_at_minor_collection)
2423 sgen_check_major_refs ();
2425 major_collector.finish_nursery_collection ();
2427 TV_GETTIME (last_minor_collection_end_tv);
2428 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2431 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2433 /* prepare the pin queue for the next collection */
2434 sgen_finish_pinning ();
2435 if (fin_ready_list || critical_fin_list) {
2436 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2437 mono_gc_finalize_notify ();
2439 sgen_pin_stats_reset ();
2440 /* clear cemented hash */
2441 sgen_cement_clear_below_threshold ();
2443 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2445 remset.finish_minor_collection ();
2447 check_scan_starts ();
2449 binary_protocol_flush_buffers (FALSE);
2451 sgen_memgov_minor_collection_end ();
2453 /*objects are late pinned because of lack of memory, so a major is a good call*/
2454 needs_major = objects_pinned > 0;
2455 current_collection_generation = -1;
2458 MONO_GC_END (GENERATION_NURSERY);
2459 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY);
2461 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2462 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2468 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2471 * This is called on all objects in the nursery, including pinned ones, so we need
2472 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2474 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2478 scan_nursery_objects (ScanCopyContext ctx)
2480 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2481 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2485 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean start_concurrent_mark, gboolean finish_up_concurrent_mark, gboolean scan_mod_union, gboolean scan_whole_nursery)
2490 /* FIXME: only use these values for the precise scan
2491 * note that to_space pointers should be excluded anyway...
2493 char *heap_start = NULL;
2494 char *heap_end = (char*)-1;
2495 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2496 GCRootReport root_report = { 0 };
2497 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2498 ScanThreadDataJobData *stdjd;
2499 ScanCopyContext ctx;
2501 if (concurrent_collection_in_progress) {
2502 /*This cleans up unused fragments */
2503 sgen_nursery_allocator_prepare_for_pinning ();
2505 if (do_concurrent_checks)
2506 check_nursery_is_clean ();
2508 /* The concurrent collector doesn't touch the nursery. */
2509 sgen_nursery_alloc_prepare_for_major ();
2516 /* Pinning depends on this */
2517 sgen_clear_nursery_fragments ();
2519 if (whole_heap_check_before_collection)
2520 sgen_check_whole_heap (finish_up_concurrent_mark);
2523 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2525 if (!sgen_collection_is_concurrent ())
2526 nursery_section->next_data = sgen_get_nursery_end ();
2527 /* we should also coalesce scanning from sections close to each other
2528 * and deal with pointers outside of the sections later.
2532 *major_collector.have_swept = FALSE;
2534 if (xdomain_checks) {
2535 sgen_clear_nursery_fragments ();
2536 sgen_check_for_xdomain_refs ();
2539 if (!concurrent_collection_in_progress) {
2540 /* Remsets are not useful for a major collection */
2541 remset.prepare_for_major_collection ();
2544 sgen_process_fin_stage_entries ();
2545 sgen_process_dislink_stage_entries ();
2548 sgen_init_pinning ();
2549 SGEN_LOG (6, "Collecting pinned addresses");
2550 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2552 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2553 if (major_collector.is_concurrent) {
2555 * The concurrent major collector cannot evict
2556 * yet, so we need to pin cemented objects to
2557 * not break some asserts.
2559 * FIXME: We could evict now!
2561 sgen_pin_cemented_objects ();
2564 if (!concurrent_collection_in_progress)
2565 sgen_cement_reset ();
2568 sgen_optimize_pin_queue ();
2571 * pin_queue now contains all candidate pointers, sorted and
2572 * uniqued. We must do two passes now to figure out which
2573 * objects are pinned.
2575 * The first is to find within the pin_queue the area for each
2576 * section. This requires that the pin_queue be sorted. We
2577 * also process the LOS objects and pinned chunks here.
2579 * The second, destructive, pass is to reduce the section
2580 * areas to pointers to the actually pinned objects.
2582 SGEN_LOG (6, "Pinning from sections");
2583 /* first pass for the sections */
2584 sgen_find_section_pin_queue_start_end (nursery_section);
2585 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2586 /* identify possible pointers to the insize of large objects */
2587 SGEN_LOG (6, "Pinning from large objects");
2588 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2590 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2591 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2593 #ifdef ENABLE_DTRACE
2594 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2595 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2596 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2600 if (sgen_los_object_is_pinned (bigobj->data)) {
2601 g_assert (finish_up_concurrent_mark);
2604 sgen_los_pin_object (bigobj->data);
2605 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2606 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2607 if (G_UNLIKELY (do_pin_stats))
2608 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2609 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data, safe_name (bigobj->data), (unsigned long)sgen_los_object_size (bigobj));
2612 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2616 notify_gc_roots (&root_report);
2617 /* second pass for the sections */
2618 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2619 ctx.copy_func = NULL;
2620 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2623 * Concurrent mark never follows references into the nursery. In the start and
2624 * finish pauses we must scan live nursery objects, though.
2626 * In the finish pause we do this conservatively by scanning all nursery objects.
2627 * Previously we would only scan pinned objects here. We assumed that all objects
2628 * that were pinned during the nursery collection immediately preceding this finish
2629 * mark would be pinned again here. Due to the way we get the stack end for the GC
2630 * thread, however, that's not necessarily the case: we scan part of the stack used
2631 * by the GC itself, which changes constantly, so pinning isn't entirely
2634 * The split nursery also complicates things because non-pinned objects can survive
2635 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2637 * In the future we shouldn't do a preceding nursery collection at all and instead
2638 * do the finish pause with promotion from the nursery.
2640 * A further complication arises when we have late-pinned objects from the preceding
2641 * nursery collection. Those are the result of being out of memory when trying to
2642 * evacuate objects. They won't be found from the roots, so we just scan the whole
2645 * Non-concurrent mark evacuates from the nursery, so it's
2646 * sufficient to just scan pinned nursery objects.
2648 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2649 scan_nursery_objects (ctx);
2651 pin_objects_in_nursery (ctx);
2652 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2653 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2656 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2657 if (old_next_pin_slot)
2658 *old_next_pin_slot = sgen_get_pinned_count ();
2661 time_major_pinning += TV_ELAPSED (atv, btv);
2662 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2663 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2665 major_collector.init_to_space ();
2668 * The concurrent collector doesn't move objects, neither on
2669 * the major heap nor in the nursery, so we can mark even
2670 * before pinning has finished. For the non-concurrent
2671 * collector we start the workers after pinning.
2673 if (start_concurrent_mark) {
2674 sgen_workers_start_all_workers ();
2675 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2678 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2679 main_gc_thread = mono_native_thread_self ();
2682 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2683 report_registered_roots ();
2685 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2687 /* registered roots, this includes static fields */
2688 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2689 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2690 scrrjd_normal->scan_func = current_object_ops.scan_object;
2691 scrrjd_normal->heap_start = heap_start;
2692 scrrjd_normal->heap_end = heap_end;
2693 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2694 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2696 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2697 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2698 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2699 scrrjd_wbarrier->heap_start = heap_start;
2700 scrrjd_wbarrier->heap_end = heap_end;
2701 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2702 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2705 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2708 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2709 stdjd->heap_start = heap_start;
2710 stdjd->heap_end = heap_end;
2711 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2714 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2717 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2719 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2720 report_finalizer_roots ();
2722 /* scan the list of objects ready for finalization */
2723 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2724 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2726 if (scan_mod_union) {
2727 g_assert (finish_up_concurrent_mark);
2729 /* Mod union card table */
2730 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2731 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2735 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2736 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2739 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2741 if (concurrent_collection_in_progress) {
2742 /* prepare the pin queue for the next collection */
2743 sgen_finish_pinning ();
2745 sgen_pin_stats_reset ();
2747 if (do_concurrent_checks)
2748 check_nursery_is_clean ();
2753 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2755 MONO_GC_BEGIN (GENERATION_OLD);
2756 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2758 current_collection_generation = GENERATION_OLD;
2759 #ifndef DISABLE_PERFCOUNTERS
2760 mono_perfcounters->gc_collections1++;
2763 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2766 g_assert (major_collector.is_concurrent);
2767 concurrent_collection_in_progress = TRUE;
2769 sgen_cement_concurrent_start ();
2771 current_object_ops = major_collector.major_concurrent_ops;
2773 current_object_ops = major_collector.major_ops;
2776 reset_pinned_from_failed_allocation ();
2778 sgen_memgov_major_collection_start ();
2780 //count_ref_nonref_objs ();
2781 //consistency_check ();
2783 check_scan_starts ();
2786 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2787 gc_stats.major_gc_count ++;
2789 if (major_collector.start_major_collection)
2790 major_collector.start_major_collection ();
2792 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent, FALSE, FALSE, FALSE);
2796 wait_for_workers_to_finish (void)
2798 while (!sgen_workers_all_done ())
2803 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union, gboolean scan_whole_nursery)
2805 LOSObject *bigobj, *prevbo;
2811 if (concurrent_collection_in_progress) {
2812 sgen_workers_signal_start_nursery_collection_and_wait ();
2814 current_object_ops = major_collector.major_concurrent_ops;
2816 major_copy_or_mark_from_roots (NULL, FALSE, TRUE, scan_mod_union, scan_whole_nursery);
2818 sgen_workers_signal_finish_nursery_collection ();
2819 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2821 sgen_workers_join ();
2823 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2825 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2826 main_gc_thread = NULL;
2829 if (do_concurrent_checks)
2830 check_nursery_is_clean ();
2832 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2833 current_object_ops = major_collector.major_ops;
2837 * The workers have stopped so we need to finish gray queue
2838 * work that might result from finalization in the main GC
2839 * thread. Redirection must therefore be turned off.
2841 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2842 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2844 /* all the objects in the heap */
2845 finish_gray_stack (GENERATION_OLD, &gray_queue);
2847 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2849 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2852 * The (single-threaded) finalization code might have done
2853 * some copying/marking so we can only reset the GC thread's
2854 * worker data here instead of earlier when we joined the
2857 sgen_workers_reset_data ();
2859 if (objects_pinned) {
2860 g_assert (!concurrent_collection_in_progress);
2863 * This is slow, but we just OOM'd.
2865 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2866 * queue is laid out at this point.
2868 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2870 * We need to reestablish all pinned nursery objects in the pin queue
2871 * because they're needed for fragment creation. Unpinning happens by
2872 * walking the whole queue, so it's not necessary to reestablish where major
2873 * heap block pins are - all we care is that they're still in there
2876 sgen_optimize_pin_queue ();
2877 sgen_find_section_pin_queue_start_end (nursery_section);
2881 reset_heap_boundaries ();
2882 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2884 if (!concurrent_collection_in_progress) {
2885 /* walk the pin_queue, build up the fragment list of free memory, unmark
2886 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2889 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2892 /* prepare the pin queue for the next collection */
2893 sgen_finish_pinning ();
2895 /* Clear TLABs for all threads */
2896 sgen_clear_tlabs ();
2898 sgen_pin_stats_reset ();
2901 if (concurrent_collection_in_progress)
2902 sgen_cement_concurrent_finish ();
2903 sgen_cement_clear_below_threshold ();
2905 if (check_mark_bits_after_major_collection)
2906 sgen_check_heap_marked (concurrent_collection_in_progress);
2909 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2912 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2914 /* sweep the big objects list */
2916 for (bigobj = los_object_list; bigobj;) {
2917 g_assert (!object_is_pinned (bigobj->data));
2918 if (sgen_los_object_is_pinned (bigobj->data)) {
2919 sgen_los_unpin_object (bigobj->data);
2920 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2923 /* not referenced anywhere, so we can free it */
2925 prevbo->next = bigobj->next;
2927 los_object_list = bigobj->next;
2929 bigobj = bigobj->next;
2930 sgen_los_free_object (to_free);
2934 bigobj = bigobj->next;
2938 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2943 time_major_los_sweep += TV_ELAPSED (atv, btv);
2945 major_collector.sweep ();
2947 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2950 time_major_sweep += TV_ELAPSED (btv, atv);
2953 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2955 if (fin_ready_list || critical_fin_list) {
2956 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2957 mono_gc_finalize_notify ();
2960 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2962 sgen_memgov_major_collection_end ();
2963 current_collection_generation = -1;
2965 major_collector.finish_major_collection ();
2967 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2969 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2970 if (concurrent_collection_in_progress)
2971 concurrent_collection_in_progress = FALSE;
2973 check_scan_starts ();
2975 binary_protocol_flush_buffers (FALSE);
2977 //consistency_check ();
2979 MONO_GC_END (GENERATION_OLD);
2980 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD);
2984 major_do_collection (const char *reason)
2986 TV_DECLARE (time_start);
2987 TV_DECLARE (time_end);
2988 size_t old_next_pin_slot;
2990 if (disable_major_collections)
2993 if (major_collector.get_and_reset_num_major_objects_marked) {
2994 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2995 g_assert (!num_marked);
2998 /* world must be stopped already */
2999 TV_GETTIME (time_start);
3001 major_start_collection (FALSE, &old_next_pin_slot);
3002 major_finish_collection (reason, old_next_pin_slot, FALSE, FALSE);
3004 TV_GETTIME (time_end);
3005 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3007 /* FIXME: also report this to the user, preferably in gc-end. */
3008 if (major_collector.get_and_reset_num_major_objects_marked)
3009 major_collector.get_and_reset_num_major_objects_marked ();
3011 return bytes_pinned_from_failed_allocation > 0;
3015 major_start_concurrent_collection (const char *reason)
3017 TV_DECLARE (time_start);
3018 TV_DECLARE (time_end);
3019 long long num_objects_marked;
3021 if (disable_major_collections)
3024 TV_GETTIME (time_start);
3025 SGEN_TV_GETTIME (time_major_conc_collection_start);
3027 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3028 g_assert (num_objects_marked == 0);
3030 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3031 binary_protocol_concurrent_start ();
3033 // FIXME: store reason and pass it when finishing
3034 major_start_collection (TRUE, NULL);
3036 gray_queue_redirect (&gray_queue);
3037 sgen_workers_wait_for_jobs_finished ();
3039 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3040 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3042 TV_GETTIME (time_end);
3043 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3045 current_collection_generation = -1;
3049 major_should_finish_concurrent_collection (void)
3051 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
3052 return sgen_workers_all_done ();
3056 major_update_concurrent_collection (void)
3058 TV_DECLARE (total_start);
3059 TV_DECLARE (total_end);
3061 TV_GETTIME (total_start);
3063 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3064 binary_protocol_concurrent_update_finish ();
3066 major_collector.update_cardtable_mod_union ();
3067 sgen_los_update_cardtable_mod_union ();
3069 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3071 TV_GETTIME (total_end);
3072 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3076 major_finish_concurrent_collection (void)
3078 TV_DECLARE (total_start);
3079 TV_DECLARE (total_end);
3080 gboolean late_pinned;
3081 SgenGrayQueue unpin_queue;
3082 memset (&unpin_queue, 0, sizeof (unpin_queue));
3084 TV_GETTIME (total_start);
3086 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3087 binary_protocol_concurrent_update_finish ();
3090 * The major collector can add global remsets which are processed in the finishing
3091 * nursery collection, below. That implies that the workers must have finished
3092 * marking before the nursery collection is allowed to run, otherwise we might miss
3095 wait_for_workers_to_finish ();
3097 SGEN_TV_GETTIME (time_major_conc_collection_end);
3098 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3100 major_collector.update_cardtable_mod_union ();
3101 sgen_los_update_cardtable_mod_union ();
3103 late_pinned = collect_nursery (&unpin_queue, TRUE);
3105 if (mod_union_consistency_check)
3106 sgen_check_mod_union_consistency ();
3108 current_collection_generation = GENERATION_OLD;
3109 major_finish_collection ("finishing", -1, TRUE, late_pinned);
3111 if (whole_heap_check_before_collection)
3112 sgen_check_whole_heap (FALSE);
3114 unpin_objects_from_queue (&unpin_queue);
3115 sgen_gray_object_queue_deinit (&unpin_queue);
3117 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3119 TV_GETTIME (total_end);
3120 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3122 current_collection_generation = -1;
3126 * Ensure an allocation request for @size will succeed by freeing enough memory.
3128 * LOCKING: The GC lock MUST be held.
3131 sgen_ensure_free_space (size_t size)
3133 int generation_to_collect = -1;
3134 const char *reason = NULL;
3137 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3138 if (sgen_need_major_collection (size)) {
3139 reason = "LOS overflow";
3140 generation_to_collect = GENERATION_OLD;
3143 if (degraded_mode) {
3144 if (sgen_need_major_collection (size)) {
3145 reason = "Degraded mode overflow";
3146 generation_to_collect = GENERATION_OLD;
3148 } else if (sgen_need_major_collection (size)) {
3149 reason = "Minor allowance";
3150 generation_to_collect = GENERATION_OLD;
3152 generation_to_collect = GENERATION_NURSERY;
3153 reason = "Nursery full";
3157 if (generation_to_collect == -1) {
3158 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3159 generation_to_collect = GENERATION_OLD;
3160 reason = "Finish concurrent collection";
3164 if (generation_to_collect == -1)
3166 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3170 * LOCKING: Assumes the GC lock is held.
3173 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3175 TV_DECLARE (gc_start);
3176 TV_DECLARE (gc_end);
3177 TV_DECLARE (gc_total_start);
3178 TV_DECLARE (gc_total_end);
3179 GGTimingInfo infos [2];
3180 int overflow_generation_to_collect = -1;
3181 int oldest_generation_collected = generation_to_collect;
3182 const char *overflow_reason = NULL;
3184 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3186 binary_protocol_collection_force (generation_to_collect);
3188 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3190 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3192 TV_GETTIME (gc_start);
3194 sgen_stop_world (generation_to_collect);
3196 TV_GETTIME (gc_total_start);
3198 if (concurrent_collection_in_progress) {
3200 * We update the concurrent collection. If it finished, we're done. If
3201 * not, and we've been asked to do a nursery collection, we do that.
3203 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3206 major_finish_concurrent_collection ();
3207 oldest_generation_collected = GENERATION_OLD;
3209 sgen_workers_signal_start_nursery_collection_and_wait ();
3211 major_update_concurrent_collection ();
3212 if (generation_to_collect == GENERATION_NURSERY)
3213 collect_nursery (NULL, FALSE);
3215 sgen_workers_signal_finish_nursery_collection ();
3222 * If we've been asked to do a major collection, and the major collector wants to
3223 * run synchronously (to evacuate), we set the flag to do that.
3225 if (generation_to_collect == GENERATION_OLD &&
3226 allow_synchronous_major &&
3227 major_collector.want_synchronous_collection &&
3228 *major_collector.want_synchronous_collection) {
3229 wait_to_finish = TRUE;
3232 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3235 * There's no concurrent collection in progress. Collect the generation we're asked
3236 * to collect. If the major collector is concurrent and we're not forced to wait,
3237 * start a concurrent collection.
3239 // FIXME: extract overflow reason
3240 if (generation_to_collect == GENERATION_NURSERY) {
3241 if (collect_nursery (NULL, FALSE)) {
3242 overflow_generation_to_collect = GENERATION_OLD;
3243 overflow_reason = "Minor overflow";
3246 if (major_collector.is_concurrent && !wait_to_finish) {
3247 collect_nursery (NULL, FALSE);
3248 major_start_concurrent_collection (reason);
3249 // FIXME: set infos[0] properly
3253 if (major_do_collection (reason)) {
3254 overflow_generation_to_collect = GENERATION_NURSERY;
3255 overflow_reason = "Excessive pinning";
3259 TV_GETTIME (gc_end);
3261 memset (infos, 0, sizeof (infos));
3262 infos [0].generation = generation_to_collect;
3263 infos [0].reason = reason;
3264 infos [0].is_overflow = FALSE;
3265 infos [1].generation = -1;
3266 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3268 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3270 if (overflow_generation_to_collect != -1) {
3272 * We need to do an overflow collection, either because we ran out of memory
3273 * or the nursery is fully pinned.
3276 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3277 infos [1].generation = overflow_generation_to_collect;
3278 infos [1].reason = overflow_reason;
3279 infos [1].is_overflow = TRUE;
3280 infos [1].total_time = gc_end;
3282 if (overflow_generation_to_collect == GENERATION_NURSERY)
3283 collect_nursery (NULL, FALSE);
3285 major_do_collection (overflow_reason);
3287 TV_GETTIME (gc_end);
3288 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3290 /* keep events symmetric */
3291 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3293 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3296 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3298 /* this also sets the proper pointers for the next allocation */
3299 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3300 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3301 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3302 sgen_dump_pin_queue ();
3307 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3309 TV_GETTIME (gc_total_end);
3310 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3312 sgen_restart_world (oldest_generation_collected, infos);
3314 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3318 * ######################################################################
3319 * ######## Memory allocation from the OS
3320 * ######################################################################
3321 * This section of code deals with getting memory from the OS and
3322 * allocating memory for GC-internal data structures.
3323 * Internal memory can be handled with a freelist for small objects.
3329 G_GNUC_UNUSED static void
3330 report_internal_mem_usage (void)
3332 printf ("Internal memory usage:\n");
3333 sgen_report_internal_mem_usage ();
3334 printf ("Pinned memory usage:\n");
3335 major_collector.report_pinned_memory_usage ();
3339 * ######################################################################
3340 * ######## Finalization support
3341 * ######################################################################
3344 static inline gboolean
3345 sgen_major_is_object_alive (void *object)
3349 /* Oldgen objects can be pinned and forwarded too */
3350 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3354 * FIXME: major_collector.is_object_live() also calculates the
3355 * size. Avoid the double calculation.
3357 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3358 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3359 return sgen_los_object_is_pinned (object);
3361 return major_collector.is_object_live (object);
3365 * If the object has been forwarded it means it's still referenced from a root.
3366 * If it is pinned it's still alive as well.
3367 * A LOS object is only alive if we have pinned it.
3368 * Return TRUE if @obj is ready to be finalized.
3370 static inline gboolean
3371 sgen_is_object_alive (void *object)
3373 if (ptr_in_nursery (object))
3374 return sgen_nursery_is_object_alive (object);
3376 return sgen_major_is_object_alive (object);
3380 * This function returns true if @object is either alive or it belongs to the old gen
3381 * and we're currently doing a minor collection.
3384 sgen_is_object_alive_for_current_gen (char *object)
3386 if (ptr_in_nursery (object))
3387 return sgen_nursery_is_object_alive (object);
3389 if (current_collection_generation == GENERATION_NURSERY)
3392 return sgen_major_is_object_alive (object);
3396 * This function returns true if @object is either alive and belongs to the
3397 * current collection - major collections are full heap, so old gen objects
3398 * are never alive during a minor collection.
3401 sgen_is_object_alive_and_on_current_collection (char *object)
3403 if (ptr_in_nursery (object))
3404 return sgen_nursery_is_object_alive (object);
3406 if (current_collection_generation == GENERATION_NURSERY)
3409 return sgen_major_is_object_alive (object);
3414 sgen_gc_is_object_ready_for_finalization (void *object)
3416 return !sgen_is_object_alive (object);
3420 has_critical_finalizer (MonoObject *obj)
3424 if (!mono_defaults.critical_finalizer_object)
3427 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3429 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3433 is_finalization_aware (MonoObject *obj)
3435 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3436 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3440 sgen_queue_finalization_entry (MonoObject *obj)
3442 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3443 gboolean critical = has_critical_finalizer (obj);
3444 entry->object = obj;
3446 entry->next = critical_fin_list;
3447 critical_fin_list = entry;
3449 entry->next = fin_ready_list;
3450 fin_ready_list = entry;
3453 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3454 fin_callbacks.object_queued_for_finalization (obj);
3456 #ifdef ENABLE_DTRACE
3457 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3458 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3459 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3460 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3461 vt->klass->name_space, vt->klass->name, gen, critical);
3467 sgen_object_is_live (void *obj)
3469 return sgen_is_object_alive_and_on_current_collection (obj);
3472 /* LOCKING: requires that the GC lock is held */
3474 null_ephemerons_for_domain (MonoDomain *domain)
3476 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3479 MonoObject *object = (MonoObject*)current->array;
3481 if (object && !object->vtable) {
3482 EphemeronLinkNode *tmp = current;
3485 prev->next = current->next;
3487 ephemeron_list = current->next;
3489 current = current->next;
3490 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3493 current = current->next;
3498 /* LOCKING: requires that the GC lock is held */
3500 clear_unreachable_ephemerons (ScanCopyContext ctx)
3502 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3503 GrayQueue *queue = ctx.queue;
3504 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3506 Ephemeron *cur, *array_end;
3510 char *object = current->array;
3512 if (!sgen_is_object_alive_for_current_gen (object)) {
3513 EphemeronLinkNode *tmp = current;
3515 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3518 prev->next = current->next;
3520 ephemeron_list = current->next;
3522 current = current->next;
3523 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3528 copy_func ((void**)&object, queue);
3529 current->array = object;
3531 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3533 array = (MonoArray*)object;
3534 cur = mono_array_addr (array, Ephemeron, 0);
3535 array_end = cur + mono_array_length_fast (array);
3536 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3538 for (; cur < array_end; ++cur) {
3539 char *key = (char*)cur->key;
3541 if (!key || key == tombstone)
3544 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3545 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3546 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3548 if (!sgen_is_object_alive_for_current_gen (key)) {
3549 cur->key = tombstone;
3555 current = current->next;
3560 LOCKING: requires that the GC lock is held
3562 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3565 mark_ephemerons_in_range (ScanCopyContext ctx)
3567 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3568 GrayQueue *queue = ctx.queue;
3569 int nothing_marked = 1;
3570 EphemeronLinkNode *current = ephemeron_list;
3572 Ephemeron *cur, *array_end;
3575 for (current = ephemeron_list; current; current = current->next) {
3576 char *object = current->array;
3577 SGEN_LOG (5, "Ephemeron array at %p", object);
3579 /*It has to be alive*/
3580 if (!sgen_is_object_alive_for_current_gen (object)) {
3581 SGEN_LOG (5, "\tnot reachable");
3585 copy_func ((void**)&object, queue);
3587 array = (MonoArray*)object;
3588 cur = mono_array_addr (array, Ephemeron, 0);
3589 array_end = cur + mono_array_length_fast (array);
3590 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3592 for (; cur < array_end; ++cur) {
3593 char *key = cur->key;
3595 if (!key || key == tombstone)
3598 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3599 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3600 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3602 if (sgen_is_object_alive_for_current_gen (key)) {
3603 char *value = cur->value;
3605 copy_func ((void**)&cur->key, queue);
3607 if (!sgen_is_object_alive_for_current_gen (value))
3609 copy_func ((void**)&cur->value, queue);
3615 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3616 return nothing_marked;
3620 mono_gc_invoke_finalizers (void)
3622 FinalizeReadyEntry *entry = NULL;
3623 gboolean entry_is_critical = FALSE;
3626 /* FIXME: batch to reduce lock contention */
3627 while (fin_ready_list || critical_fin_list) {
3631 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3633 /* We have finalized entry in the last
3634 interation, now we need to remove it from
3637 *list = entry->next;
3639 FinalizeReadyEntry *e = *list;
3640 while (e->next != entry)
3642 e->next = entry->next;
3644 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3648 /* Now look for the first non-null entry. */
3649 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3652 entry_is_critical = FALSE;
3654 entry_is_critical = TRUE;
3655 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3660 g_assert (entry->object);
3661 num_ready_finalizers--;
3662 obj = entry->object;
3663 entry->object = NULL;
3664 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3672 g_assert (entry->object == NULL);
3674 /* the object is on the stack so it is pinned */
3675 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3676 mono_gc_run_finalize (obj, NULL);
3683 mono_gc_pending_finalizers (void)
3685 return fin_ready_list || critical_fin_list;
3689 * ######################################################################
3690 * ######## registered roots support
3691 * ######################################################################
3695 * We do not coalesce roots.
3698 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3700 RootRecord new_root;
3703 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3704 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3705 /* we allow changing the size and the descriptor (for thread statics etc) */
3707 size_t old_size = root->end_root - start;
3708 root->end_root = start + size;
3709 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3710 ((root->root_desc == 0) && (descr == NULL)));
3711 root->root_desc = (mword)descr;
3713 roots_size -= old_size;
3719 new_root.end_root = start + size;
3720 new_root.root_desc = (mword)descr;
3722 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3725 SGEN_LOG (3, "Added root for range: %p-%p, descr: %p (%d/%d bytes)", start, new_root.end_root, descr, (int)size, (int)roots_size);
3732 mono_gc_register_root (char *start, size_t size, void *descr)
3734 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3738 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3740 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3744 mono_gc_deregister_root (char* addr)
3750 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3751 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3752 roots_size -= (root.end_root - addr);
3758 * ######################################################################
3759 * ######## Thread handling (stop/start code)
3760 * ######################################################################
3763 unsigned int sgen_global_stop_count = 0;
3766 sgen_get_current_collection_generation (void)
3768 return current_collection_generation;
3772 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3774 gc_callbacks = *callbacks;
3778 mono_gc_get_gc_callbacks ()
3780 return &gc_callbacks;
3783 /* Variables holding start/end nursery so it won't have to be passed at every call */
3784 static void *scan_area_arg_start, *scan_area_arg_end;
3787 mono_gc_conservatively_scan_area (void *start, void *end)
3789 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3793 mono_gc_scan_object (void *obj, void *gc_data)
3795 UserCopyOrMarkData *data = gc_data;
3796 current_object_ops.copy_or_mark_object (&obj, data->queue);
3801 * Mark from thread stacks and registers.
3804 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3806 SgenThreadInfo *info;
3808 scan_area_arg_start = start_nursery;
3809 scan_area_arg_end = end_nursery;
3811 FOREACH_THREAD (info) {
3813 SGEN_LOG (3, "Skipping dead thread %p, range: %p-%p, size: %td", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start);
3816 if (info->gc_disabled) {
3817 SGEN_LOG (3, "GC disabled for thread %p, range: %p-%p, size: %td", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start);
3820 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3821 SGEN_LOG (3, "Skipping non-running thread %p, range: %p-%p, size: %td (state %d)", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, mono_thread_info_run_state (info));
3824 SGEN_LOG (3, "Scanning thread %p, range: %p-%p, size: %td, pinned=%zd", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, sgen_get_pinned_count ());
3825 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3826 UserCopyOrMarkData data = { NULL, queue };
3827 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3828 } else if (!precise) {
3829 if (!conservative_stack_mark) {
3830 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3831 conservative_stack_mark = TRUE;
3833 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3838 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3839 start_nursery, end_nursery, PIN_TYPE_STACK);
3841 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3842 start_nursery, end_nursery, PIN_TYPE_STACK);
3845 } END_FOREACH_THREAD
3849 ptr_on_stack (void *ptr)
3851 gpointer stack_start = &stack_start;
3852 SgenThreadInfo *info = mono_thread_info_current ();
3854 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3860 sgen_thread_register (SgenThreadInfo* info, void *addr)
3863 guint8 *staddr = NULL;
3865 #ifndef HAVE_KW_THREAD
3866 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3868 g_assert (!mono_native_tls_get_value (thread_info_key));
3869 mono_native_tls_set_value (thread_info_key, info);
3871 sgen_thread_info = info;
3874 #ifdef SGEN_POSIX_STW
3875 info->stop_count = -1;
3879 info->stack_start = NULL;
3880 info->stopped_ip = NULL;
3881 info->stopped_domain = NULL;
3883 memset (&info->ctx, 0, sizeof (MonoContext));
3885 memset (&info->regs, 0, sizeof (info->regs));
3888 sgen_init_tlab_info (info);
3890 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3892 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3893 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3896 info->stack_start_limit = staddr;
3898 info->stack_end = staddr + stsize;
3900 gsize stack_bottom = (gsize)addr;
3901 stack_bottom += 4095;
3902 stack_bottom &= ~4095;
3903 info->stack_end = (char*)stack_bottom;
3906 #ifdef HAVE_KW_THREAD
3907 stack_end = info->stack_end;
3910 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3912 if (gc_callbacks.thread_attach_func)
3913 info->runtime_data = gc_callbacks.thread_attach_func ();
3918 sgen_thread_detach (SgenThreadInfo *p)
3920 /* If a delegate is passed to native code and invoked on a thread we dont
3921 * know about, the jit will register it with mono_jit_thread_attach, but
3922 * we have no way of knowing when that thread goes away. SGen has a TSD
3923 * so we assume that if the domain is still registered, we can detach
3926 if (mono_domain_get ())
3927 mono_thread_detach_internal (mono_thread_internal_current ());
3931 sgen_thread_unregister (SgenThreadInfo *p)
3933 MonoNativeThreadId tid;
3935 tid = mono_thread_info_get_tid (p);
3936 binary_protocol_thread_unregister ((gpointer)tid);
3937 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3939 #ifndef HAVE_KW_THREAD
3940 mono_native_tls_set_value (thread_info_key, NULL);
3942 sgen_thread_info = NULL;
3945 if (p->info.runtime_thread)
3946 mono_threads_add_joinable_thread ((gpointer)tid);
3948 if (gc_callbacks.thread_detach_func) {
3949 gc_callbacks.thread_detach_func (p->runtime_data);
3950 p->runtime_data = NULL;
3956 sgen_thread_attach (SgenThreadInfo *info)
3959 /*this is odd, can we get attached before the gc is inited?*/
3963 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3964 info->runtime_data = gc_callbacks.thread_attach_func ();
3967 mono_gc_register_thread (void *baseptr)
3969 return mono_thread_info_attach (baseptr) != NULL;
3973 * mono_gc_set_stack_end:
3975 * Set the end of the current threads stack to STACK_END. The stack space between
3976 * STACK_END and the real end of the threads stack will not be scanned during collections.
3979 mono_gc_set_stack_end (void *stack_end)
3981 SgenThreadInfo *info;
3984 info = mono_thread_info_current ();
3986 g_assert (stack_end < info->stack_end);
3987 info->stack_end = stack_end;
3992 #if USE_PTHREAD_INTERCEPT
3996 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3998 return pthread_create (new_thread, attr, start_routine, arg);
4002 mono_gc_pthread_join (pthread_t thread, void **retval)
4004 return pthread_join (thread, retval);
4008 mono_gc_pthread_detach (pthread_t thread)
4010 return pthread_detach (thread);
4014 mono_gc_pthread_exit (void *retval)
4016 mono_thread_info_detach ();
4017 pthread_exit (retval);
4018 g_assert_not_reached ();
4021 #endif /* USE_PTHREAD_INTERCEPT */
4024 * ######################################################################
4025 * ######## Write barriers
4026 * ######################################################################
4030 * Note: the write barriers first do the needed GC work and then do the actual store:
4031 * this way the value is visible to the conservative GC scan after the write barrier
4032 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4033 * the conservative scan, otherwise by the remembered set scan.
4036 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4038 HEAVY_STAT (++stat_wbarrier_set_field);
4039 if (ptr_in_nursery (field_ptr)) {
4040 *(void**)field_ptr = value;
4043 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4045 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4047 remset.wbarrier_set_field (obj, field_ptr, value);
4051 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4053 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4054 if (ptr_in_nursery (slot_ptr)) {
4055 *(void**)slot_ptr = value;
4058 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4060 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4062 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4066 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4068 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4069 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4070 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4071 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4075 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4076 if (binary_protocol_is_heavy_enabled ()) {
4078 for (i = 0; i < count; ++i) {
4079 gpointer dest = (gpointer*)dest_ptr + i;
4080 gpointer obj = *((gpointer*)src_ptr + i);
4082 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4087 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4090 static char *found_obj;
4093 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4095 char *ptr = user_data;
4097 if (ptr >= obj && ptr < obj + size) {
4098 g_assert (!found_obj);
4103 /* for use in the debugger */
4104 char* find_object_for_ptr (char *ptr);
4106 find_object_for_ptr (char *ptr)
4108 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4110 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4111 find_object_for_ptr_callback, ptr, TRUE);
4117 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4122 * Very inefficient, but this is debugging code, supposed to
4123 * be called from gdb, so we don't care.
4126 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4131 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4135 HEAVY_STAT (++stat_wbarrier_generic_store);
4137 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4138 /* FIXME: ptr_in_heap must be called with the GC lock held */
4139 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4140 char *start = find_object_for_ptr (ptr);
4141 MonoObject *value = *(MonoObject**)ptr;
4145 MonoObject *obj = (MonoObject*)start;
4146 if (obj->vtable->domain != value->vtable->domain)
4147 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4153 obj = *(gpointer*)ptr;
4155 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4157 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4158 SGEN_LOG (8, "Skipping remset at %p", ptr);
4163 * We need to record old->old pointer locations for the
4164 * concurrent collector.
4166 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4167 SGEN_LOG (8, "Skipping remset at %p", ptr);
4171 SGEN_LOG (8, "Adding remset at %p", ptr);
4173 remset.wbarrier_generic_nostore (ptr);
4177 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4179 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4180 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4181 if (ptr_in_nursery (value))
4182 mono_gc_wbarrier_generic_nostore (ptr);
4183 sgen_dummy_use (value);
4186 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4187 * as an atomic operation with release semantics.
4190 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4192 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4194 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4196 InterlockedWritePointer (ptr, value);
4198 if (ptr_in_nursery (value))
4199 mono_gc_wbarrier_generic_nostore (ptr);
4201 sgen_dummy_use (value);
4204 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4206 mword *dest = _dest;
4211 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4213 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4216 size -= SIZEOF_VOID_P;
4221 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4223 #define HANDLE_PTR(ptr,obj) do { \
4224 gpointer o = *(gpointer*)(ptr); \
4226 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4227 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4232 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4234 #define SCAN_OBJECT_NOVTABLE
4235 #include "sgen-scan-object.h"
4240 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4242 HEAVY_STAT (++stat_wbarrier_value_copy);
4243 g_assert (klass->valuetype);
4245 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4247 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4248 size_t element_size = mono_class_value_size (klass, NULL);
4249 size_t size = count * element_size;
4250 mono_gc_memmove_atomic (dest, src, size);
4254 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4255 if (binary_protocol_is_heavy_enabled ()) {
4256 size_t element_size = mono_class_value_size (klass, NULL);
4258 for (i = 0; i < count; ++i) {
4259 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4260 (char*)src + i * element_size - sizeof (MonoObject),
4261 (mword) klass->gc_descr);
4266 remset.wbarrier_value_copy (dest, src, count, klass);
4270 * mono_gc_wbarrier_object_copy:
4272 * Write barrier to call when obj is the result of a clone or copy of an object.
4275 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4279 HEAVY_STAT (++stat_wbarrier_object_copy);
4281 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4282 size = mono_object_class (obj)->instance_size;
4283 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4284 size - sizeof (MonoObject));
4288 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4289 if (binary_protocol_is_heavy_enabled ())
4290 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4293 remset.wbarrier_object_copy (obj, src);
4298 * ######################################################################
4299 * ######## Other mono public interface functions.
4300 * ######################################################################
4303 #define REFS_SIZE 128
4306 MonoGCReferences callback;
4310 MonoObject *refs [REFS_SIZE];
4311 uintptr_t offsets [REFS_SIZE];
4315 #define HANDLE_PTR(ptr,obj) do { \
4317 if (hwi->count == REFS_SIZE) { \
4318 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4322 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4323 hwi->refs [hwi->count++] = *(ptr); \
4328 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4330 mword desc = sgen_obj_get_descriptor (start);
4332 #include "sgen-scan-object.h"
4336 walk_references (char *start, size_t size, void *data)
4338 HeapWalkInfo *hwi = data;
4341 collect_references (hwi, start, size);
4342 if (hwi->count || !hwi->called)
4343 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4347 * mono_gc_walk_heap:
4348 * @flags: flags for future use
4349 * @callback: a function pointer called for each object in the heap
4350 * @data: a user data pointer that is passed to callback
4352 * This function can be used to iterate over all the live objects in the heap:
4353 * for each object, @callback is invoked, providing info about the object's
4354 * location in memory, its class, its size and the objects it references.
4355 * For each referenced object it's offset from the object address is
4356 * reported in the offsets array.
4357 * The object references may be buffered, so the callback may be invoked
4358 * multiple times for the same object: in all but the first call, the size
4359 * argument will be zero.
4360 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4361 * profiler event handler.
4363 * Returns: a non-zero value if the GC doesn't support heap walking
4366 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4371 hwi.callback = callback;
4374 sgen_clear_nursery_fragments ();
4375 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4377 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4378 sgen_los_iterate_objects (walk_references, &hwi);
4384 mono_gc_collect (int generation)
4389 sgen_perform_collection (0, generation, "user request", TRUE);
4394 mono_gc_max_generation (void)
4400 mono_gc_collection_count (int generation)
4402 if (generation == 0)
4403 return gc_stats.minor_gc_count;
4404 return gc_stats.major_gc_count;
4408 mono_gc_get_used_size (void)
4412 tot = los_memory_usage;
4413 tot += nursery_section->next_data - nursery_section->data;
4414 tot += major_collector.get_used_size ();
4415 /* FIXME: account for pinned objects */
4421 mono_gc_get_los_limit (void)
4423 return MAX_SMALL_OBJ_SIZE;
4427 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4429 mono_unichar2 *new_end = str->chars + new_length;
4431 /* zero the discarded string. This null-delimits the string and allows
4432 * the space to be reclaimed by SGen. */
4434 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4435 CHECK_CANARY_FOR_OBJECT (str);
4436 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4437 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4439 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4442 str->length = new_length;
4446 mono_gc_user_markers_supported (void)
4452 mono_object_is_alive (MonoObject* o)
4458 mono_gc_get_generation (MonoObject *obj)
4460 if (ptr_in_nursery (obj))
4466 mono_gc_enable_events (void)
4471 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4473 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4477 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4479 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4483 mono_gc_weak_link_get (void **link_addr)
4485 void * volatile *link_addr_volatile;
4489 link_addr_volatile = link_addr;
4490 ptr = (void*)*link_addr_volatile;
4492 * At this point we have a hidden pointer. If the GC runs
4493 * here, it will not recognize the hidden pointer as a
4494 * reference, and if the object behind it is not referenced
4495 * elsewhere, it will be freed. Once the world is restarted
4496 * we reveal the pointer, giving us a pointer to a freed
4497 * object. To make sure we don't return it, we load the
4498 * hidden pointer again. If it's still the same, we can be
4499 * sure the object reference is valid.
4502 obj = (MonoObject*) REVEAL_POINTER (ptr);
4506 mono_memory_barrier ();
4509 * During the second bridge processing step the world is
4510 * running again. That step processes all weak links once
4511 * more to null those that refer to dead objects. Before that
4512 * is completed, those links must not be followed, so we
4513 * conservatively wait for bridge processing when any weak
4514 * link is dereferenced.
4516 if (G_UNLIKELY (bridge_processing_in_progress))
4517 mono_gc_wait_for_bridge_processing ();
4519 if ((void*)*link_addr_volatile != ptr)
4526 mono_gc_ephemeron_array_add (MonoObject *obj)
4528 EphemeronLinkNode *node;
4532 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4537 node->array = (char*)obj;
4538 node->next = ephemeron_list;
4539 ephemeron_list = node;
4541 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4548 mono_gc_set_allow_synchronous_major (gboolean flag)
4550 if (!major_collector.is_concurrent)
4553 allow_synchronous_major = flag;
4558 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4562 result = func (data);
4563 UNLOCK_INTERRUPTION;
4568 mono_gc_is_gc_thread (void)
4572 result = mono_thread_info_current () != NULL;
4578 is_critical_method (MonoMethod *method)
4580 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4584 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4588 va_start (ap, description_format);
4590 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4591 vfprintf (stderr, description_format, ap);
4593 fprintf (stderr, " - %s", fallback);
4594 fprintf (stderr, "\n");
4600 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4603 double val = strtod (opt, &endptr);
4604 if (endptr == opt) {
4605 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4608 else if (val < min || val > max) {
4609 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4617 mono_gc_base_init (void)
4619 MonoThreadInfoCallbacks cb;
4622 char *major_collector_opt = NULL;
4623 char *minor_collector_opt = NULL;
4624 size_t max_heap = 0;
4625 size_t soft_limit = 0;
4628 gboolean debug_print_allowance = FALSE;
4629 double allowance_ratio = 0, save_target = 0;
4630 gboolean have_split_nursery = FALSE;
4631 gboolean cement_enabled = TRUE;
4633 mono_counters_init ();
4636 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4639 /* already inited */
4642 /* being inited by another thread */
4646 /* we will init it */
4649 g_assert_not_reached ();
4651 } while (result != 0);
4653 SGEN_TV_GETTIME (sgen_init_timestamp);
4655 LOCK_INIT (gc_mutex);
4657 pagesize = mono_pagesize ();
4658 gc_debug_file = stderr;
4660 cb.thread_register = sgen_thread_register;
4661 cb.thread_detach = sgen_thread_detach;
4662 cb.thread_unregister = sgen_thread_unregister;
4663 cb.thread_attach = sgen_thread_attach;
4664 cb.mono_method_is_critical = (gpointer)is_critical_method;
4666 cb.thread_exit = mono_gc_pthread_exit;
4667 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4670 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4672 LOCK_INIT (sgen_interruption_mutex);
4673 LOCK_INIT (pin_queue_mutex);
4675 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4676 opts = g_strsplit (env, ",", -1);
4677 for (ptr = opts; *ptr; ++ptr) {
4679 if (g_str_has_prefix (opt, "major=")) {
4680 opt = strchr (opt, '=') + 1;
4681 major_collector_opt = g_strdup (opt);
4682 } else if (g_str_has_prefix (opt, "minor=")) {
4683 opt = strchr (opt, '=') + 1;
4684 minor_collector_opt = g_strdup (opt);
4692 sgen_init_internal_allocator ();
4693 sgen_init_nursery_allocator ();
4694 sgen_init_fin_weak_hash ();
4696 sgen_init_hash_table ();
4697 sgen_init_descriptors ();
4698 sgen_init_gray_queues ();
4700 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4701 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4702 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4703 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4705 #ifndef HAVE_KW_THREAD
4706 mono_native_tls_alloc (&thread_info_key, NULL);
4707 #if defined(__APPLE__) || defined (HOST_WIN32)
4709 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4710 * where the two are the same.
4712 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4716 int tls_offset = -1;
4717 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4718 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4723 * This needs to happen before any internal allocations because
4724 * it inits the small id which is required for hazard pointer
4729 mono_thread_info_attach (&dummy);
4731 if (!minor_collector_opt) {
4732 sgen_simple_nursery_init (&sgen_minor_collector);
4734 if (!strcmp (minor_collector_opt, "simple")) {
4736 sgen_simple_nursery_init (&sgen_minor_collector);
4737 } else if (!strcmp (minor_collector_opt, "split")) {
4738 sgen_split_nursery_init (&sgen_minor_collector);
4739 have_split_nursery = TRUE;
4741 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4742 goto use_simple_nursery;
4746 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4747 use_marksweep_major:
4748 sgen_marksweep_init (&major_collector);
4749 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4750 sgen_marksweep_conc_init (&major_collector);
4752 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4753 goto use_marksweep_major;
4756 ///* Keep this the default for now */
4757 /* Precise marking is broken on all supported targets. Disable until fixed. */
4758 conservative_stack_mark = TRUE;
4760 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4763 gboolean usage_printed = FALSE;
4765 for (ptr = opts; *ptr; ++ptr) {
4767 if (!strcmp (opt, ""))
4769 if (g_str_has_prefix (opt, "major="))
4771 if (g_str_has_prefix (opt, "minor="))
4773 if (g_str_has_prefix (opt, "max-heap-size=")) {
4774 size_t max_heap_candidate = 0;
4775 opt = strchr (opt, '=') + 1;
4776 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4777 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4778 if (max_heap != max_heap_candidate)
4779 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4781 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4785 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4786 opt = strchr (opt, '=') + 1;
4787 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4788 if (soft_limit <= 0) {
4789 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4793 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4797 if (g_str_has_prefix (opt, "stack-mark=")) {
4798 opt = strchr (opt, '=') + 1;
4799 if (!strcmp (opt, "precise")) {
4800 conservative_stack_mark = FALSE;
4801 } else if (!strcmp (opt, "conservative")) {
4802 conservative_stack_mark = TRUE;
4804 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4805 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4809 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4810 opt = strchr (opt, '=') + 1;
4811 sgen_set_bridge_implementation (opt);
4814 if (g_str_has_prefix (opt, "toggleref-test")) {
4815 sgen_register_test_toggleref_callback ();
4820 if (g_str_has_prefix (opt, "nursery-size=")) {
4822 opt = strchr (opt, '=') + 1;
4823 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4824 #ifdef SGEN_ALIGN_NURSERY
4825 if ((val & (val - 1))) {
4826 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4830 if (val < SGEN_MAX_NURSERY_WASTE) {
4831 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4832 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4836 sgen_nursery_size = val;
4837 sgen_nursery_bits = 0;
4838 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4841 sgen_nursery_size = val;
4844 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4850 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4852 opt = strchr (opt, '=') + 1;
4853 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4854 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4859 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4861 opt = strchr (opt, '=') + 1;
4862 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4863 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4864 allowance_ratio = val;
4868 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4869 if (!major_collector.is_concurrent) {
4870 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4874 opt = strchr (opt, '=') + 1;
4876 if (!strcmp (opt, "yes")) {
4877 allow_synchronous_major = TRUE;
4878 } else if (!strcmp (opt, "no")) {
4879 allow_synchronous_major = FALSE;
4881 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4886 if (!strcmp (opt, "cementing")) {
4887 cement_enabled = TRUE;
4890 if (!strcmp (opt, "no-cementing")) {
4891 cement_enabled = FALSE;
4895 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4898 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4901 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4906 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4907 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4908 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4909 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4910 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4911 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4912 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4913 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4914 fprintf (stderr, " [no-]cementing\n");
4915 if (major_collector.is_concurrent)
4916 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4917 if (major_collector.print_gc_param_usage)
4918 major_collector.print_gc_param_usage ();
4919 if (sgen_minor_collector.print_gc_param_usage)
4920 sgen_minor_collector.print_gc_param_usage ();
4921 fprintf (stderr, " Experimental options:\n");
4922 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4923 fprintf (stderr, " default-allowance-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO);
4924 fprintf (stderr, "\n");
4926 usage_printed = TRUE;
4931 if (major_collector.is_concurrent)
4932 sgen_workers_init (1);
4934 if (major_collector_opt)
4935 g_free (major_collector_opt);
4937 if (minor_collector_opt)
4938 g_free (minor_collector_opt);
4942 sgen_cement_init (cement_enabled);
4944 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4945 gboolean usage_printed = FALSE;
4947 opts = g_strsplit (env, ",", -1);
4948 for (ptr = opts; ptr && *ptr; ptr ++) {
4950 if (!strcmp (opt, ""))
4952 if (opt [0] >= '0' && opt [0] <= '9') {
4953 gc_debug_level = atoi (opt);
4958 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4959 gc_debug_file = fopen (rf, "wb");
4961 gc_debug_file = stderr;
4964 } else if (!strcmp (opt, "print-allowance")) {
4965 debug_print_allowance = TRUE;
4966 } else if (!strcmp (opt, "print-pinning")) {
4967 do_pin_stats = TRUE;
4968 } else if (!strcmp (opt, "verify-before-allocs")) {
4969 verify_before_allocs = 1;
4970 has_per_allocation_action = TRUE;
4971 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4972 char *arg = strchr (opt, '=') + 1;
4973 verify_before_allocs = atoi (arg);
4974 has_per_allocation_action = TRUE;
4975 } else if (!strcmp (opt, "collect-before-allocs")) {
4976 collect_before_allocs = 1;
4977 has_per_allocation_action = TRUE;
4978 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4979 char *arg = strchr (opt, '=') + 1;
4980 has_per_allocation_action = TRUE;
4981 collect_before_allocs = atoi (arg);
4982 } else if (!strcmp (opt, "verify-before-collections")) {
4983 whole_heap_check_before_collection = TRUE;
4984 } else if (!strcmp (opt, "check-at-minor-collections")) {
4985 consistency_check_at_minor_collection = TRUE;
4986 nursery_clear_policy = CLEAR_AT_GC;
4987 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4988 if (!major_collector.is_concurrent) {
4989 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4992 mod_union_consistency_check = TRUE;
4993 } else if (!strcmp (opt, "check-mark-bits")) {
4994 check_mark_bits_after_major_collection = TRUE;
4995 } else if (!strcmp (opt, "check-nursery-pinned")) {
4996 check_nursery_objects_pinned = TRUE;
4997 } else if (!strcmp (opt, "xdomain-checks")) {
4998 xdomain_checks = TRUE;
4999 } else if (!strcmp (opt, "clear-at-gc")) {
5000 nursery_clear_policy = CLEAR_AT_GC;
5001 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5002 nursery_clear_policy = CLEAR_AT_GC;
5003 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
5004 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
5005 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
5006 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
5007 } else if (!strcmp (opt, "check-scan-starts")) {
5008 do_scan_starts_check = TRUE;
5009 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5010 do_verify_nursery = TRUE;
5011 } else if (!strcmp (opt, "check-concurrent")) {
5012 if (!major_collector.is_concurrent) {
5013 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5016 do_concurrent_checks = TRUE;
5017 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5018 do_dump_nursery_content = TRUE;
5019 } else if (!strcmp (opt, "no-managed-allocator")) {
5020 sgen_set_use_managed_allocator (FALSE);
5021 } else if (!strcmp (opt, "disable-minor")) {
5022 disable_minor_collections = TRUE;
5023 } else if (!strcmp (opt, "disable-major")) {
5024 disable_major_collections = TRUE;
5025 } else if (g_str_has_prefix (opt, "heap-dump=")) {
5026 char *filename = strchr (opt, '=') + 1;
5027 nursery_clear_policy = CLEAR_AT_GC;
5028 heap_dump_file = fopen (filename, "w");
5029 if (heap_dump_file) {
5030 fprintf (heap_dump_file, "<sgen-dump>\n");
5031 do_pin_stats = TRUE;
5033 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5034 char *filename = strchr (opt, '=') + 1;
5035 char *colon = strrchr (filename, ':');
5038 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
5039 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
5044 binary_protocol_init (filename, (long long)limit);
5045 } else if (!strcmp (opt, "nursery-canaries")) {
5046 do_verify_nursery = TRUE;
5047 sgen_set_use_managed_allocator (FALSE);
5048 enable_nursery_canaries = TRUE;
5049 } else if (!sgen_bridge_handle_gc_debug (opt)) {
5050 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5055 fprintf (stderr, "\n%s must be of the format [<l>[:<filename>]|<option>]+ where <l> is a debug level 0-9.\n", MONO_GC_DEBUG_NAME);
5056 fprintf (stderr, "Valid <option>s are:\n");
5057 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5058 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5059 fprintf (stderr, " check-at-minor-collections\n");
5060 fprintf (stderr, " check-mark-bits\n");
5061 fprintf (stderr, " check-nursery-pinned\n");
5062 fprintf (stderr, " verify-before-collections\n");
5063 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5064 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5065 fprintf (stderr, " disable-minor\n");
5066 fprintf (stderr, " disable-major\n");
5067 fprintf (stderr, " xdomain-checks\n");
5068 fprintf (stderr, " check-concurrent\n");
5069 fprintf (stderr, " clear-[nursery-]at-gc\n");
5070 fprintf (stderr, " clear-at-tlab-creation\n");
5071 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5072 fprintf (stderr, " check-scan-starts\n");
5073 fprintf (stderr, " no-managed-allocator\n");
5074 fprintf (stderr, " print-allowance\n");
5075 fprintf (stderr, " print-pinning\n");
5076 fprintf (stderr, " heap-dump=<filename>\n");
5077 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5078 fprintf (stderr, " nursery-canaries\n");
5079 sgen_bridge_print_gc_debug_usage ();
5080 fprintf (stderr, "\n");
5082 usage_printed = TRUE;
5088 if (check_mark_bits_after_major_collection)
5089 nursery_clear_policy = CLEAR_AT_GC;
5091 if (major_collector.post_param_init)
5092 major_collector.post_param_init (&major_collector);
5094 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5096 memset (&remset, 0, sizeof (remset));
5098 sgen_card_table_init (&remset);
5104 mono_gc_get_gc_name (void)
5109 static MonoMethod *write_barrier_method;
5112 sgen_is_critical_method (MonoMethod *method)
5114 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5118 sgen_has_critical_method (void)
5120 return write_barrier_method || sgen_has_managed_allocator ();
5126 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5128 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5129 #ifdef SGEN_ALIGN_NURSERY
5130 // if (ptr_in_nursery (ptr)) return;
5132 * Masking out the bits might be faster, but we would have to use 64 bit
5133 * immediates, which might be slower.
5135 mono_mb_emit_ldarg (mb, 0);
5136 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5137 mono_mb_emit_byte (mb, CEE_SHR_UN);
5138 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5139 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5141 if (!major_collector.is_concurrent) {
5142 // if (!ptr_in_nursery (*ptr)) return;
5143 mono_mb_emit_ldarg (mb, 0);
5144 mono_mb_emit_byte (mb, CEE_LDIND_I);
5145 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5146 mono_mb_emit_byte (mb, CEE_SHR_UN);
5147 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5148 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5151 int label_continue1, label_continue2;
5152 int dereferenced_var;
5154 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5155 mono_mb_emit_ldarg (mb, 0);
5156 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5157 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5159 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5160 mono_mb_emit_ldarg (mb, 0);
5161 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5162 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5165 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5168 mono_mb_patch_branch (mb, label_continue_1);
5169 mono_mb_patch_branch (mb, label_continue_2);
5171 // Dereference and store in local var
5172 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5173 mono_mb_emit_ldarg (mb, 0);
5174 mono_mb_emit_byte (mb, CEE_LDIND_I);
5175 mono_mb_emit_stloc (mb, dereferenced_var);
5177 if (!major_collector.is_concurrent) {
5178 // if (*ptr < sgen_get_nursery_start ()) return;
5179 mono_mb_emit_ldloc (mb, dereferenced_var);
5180 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5181 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5183 // if (*ptr >= sgen_get_nursery_end ()) return;
5184 mono_mb_emit_ldloc (mb, dereferenced_var);
5185 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5186 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5193 mono_gc_get_write_barrier (void)
5196 MonoMethodBuilder *mb;
5197 MonoMethodSignature *sig;
5198 #ifdef MANAGED_WBARRIER
5199 int i, nursery_check_labels [3];
5201 #ifdef HAVE_KW_THREAD
5202 int stack_end_offset = -1;
5204 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5205 g_assert (stack_end_offset != -1);
5209 // FIXME: Maybe create a separate version for ctors (the branch would be
5210 // correctly predicted more times)
5211 if (write_barrier_method)
5212 return write_barrier_method;
5214 /* Create the IL version of mono_gc_barrier_generic_store () */
5215 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5216 sig->ret = &mono_defaults.void_class->byval_arg;
5217 sig->params [0] = &mono_defaults.int_class->byval_arg;
5219 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5222 #ifdef MANAGED_WBARRIER
5223 emit_nursery_check (mb, nursery_check_labels);
5225 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5229 LDC_PTR sgen_cardtable
5231 address >> CARD_BITS
5235 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5236 LDC_PTR card_table_mask
5243 mono_mb_emit_ptr (mb, sgen_cardtable);
5244 mono_mb_emit_ldarg (mb, 0);
5245 mono_mb_emit_icon (mb, CARD_BITS);
5246 mono_mb_emit_byte (mb, CEE_SHR_UN);
5247 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5248 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5249 mono_mb_emit_byte (mb, CEE_AND);
5251 mono_mb_emit_byte (mb, CEE_ADD);
5252 mono_mb_emit_icon (mb, 1);
5253 mono_mb_emit_byte (mb, CEE_STIND_I1);
5256 for (i = 0; i < 3; ++i) {
5257 if (nursery_check_labels [i])
5258 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5260 mono_mb_emit_byte (mb, CEE_RET);
5262 mono_mb_emit_ldarg (mb, 0);
5263 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5264 mono_mb_emit_byte (mb, CEE_RET);
5267 res = mono_mb_create_method (mb, sig, 16);
5271 if (write_barrier_method) {
5272 /* Already created */
5273 mono_free_method (res);
5275 /* double-checked locking */
5276 mono_memory_barrier ();
5277 write_barrier_method = res;
5281 return write_barrier_method;
5285 mono_gc_get_description (void)
5287 return g_strdup ("sgen");
5291 mono_gc_set_desktop_mode (void)
5296 mono_gc_is_moving (void)
5302 mono_gc_is_disabled (void)
5308 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5315 sgen_get_nursery_clear_policy (void)
5317 return nursery_clear_policy;
5321 sgen_get_array_fill_vtable (void)
5323 if (!array_fill_vtable) {
5324 static MonoClass klass;
5325 static MonoVTable vtable;
5328 MonoDomain *domain = mono_get_root_domain ();
5331 klass.element_class = mono_defaults.byte_class;
5333 klass.instance_size = sizeof (MonoArray);
5334 klass.sizes.element_size = 1;
5335 klass.name = "array_filler_type";
5337 vtable.klass = &klass;
5339 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5342 array_fill_vtable = &vtable;
5344 return array_fill_vtable;
5354 sgen_gc_unlock (void)
5356 gboolean try_free = sgen_try_free_some_memory;
5357 sgen_try_free_some_memory = FALSE;
5358 mono_mutex_unlock (&gc_mutex);
5359 MONO_GC_UNLOCKED ();
5361 mono_thread_hazardous_try_free_some ();
5365 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5367 major_collector.iterate_live_block_ranges (callback);
5371 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5373 major_collector.scan_card_table (FALSE, queue);
5377 sgen_get_major_collector (void)
5379 return &major_collector;
5382 void mono_gc_set_skip_thread (gboolean skip)
5384 SgenThreadInfo *info = mono_thread_info_current ();
5387 info->gc_disabled = skip;
5392 sgen_get_remset (void)
5398 mono_gc_get_vtable_bits (MonoClass *class)
5401 /* FIXME move this to the bridge code */
5402 if (sgen_need_bridge_processing ()) {
5403 switch (sgen_bridge_class_kind (class)) {
5404 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5405 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5406 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5408 case GC_BRIDGE_OPAQUE_CLASS:
5409 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5413 if (fin_callbacks.is_class_finalization_aware) {
5414 if (fin_callbacks.is_class_finalization_aware (class))
5415 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5421 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5428 sgen_check_whole_heap_stw (void)
5430 sgen_stop_world (0);
5431 sgen_clear_nursery_fragments ();
5432 sgen_check_whole_heap (FALSE);
5433 sgen_restart_world (0, NULL);
5437 sgen_gc_event_moves (void)
5439 if (moved_objects_idx) {
5440 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5441 moved_objects_idx = 0;
5446 sgen_timestamp (void)
5448 SGEN_TV_DECLARE (timestamp);
5449 SGEN_TV_GETTIME (timestamp);
5450 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5454 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5456 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5457 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5459 fin_callbacks = *callbacks;
5466 #endif /* HAVE_SGEN_GC */