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 mword lowest_heap_address = ~(mword)0;
429 static 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 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
626 while (start < end) {
630 if (!*(void**)start) {
631 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
636 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
642 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
643 CHECK_CANARY_FOR_OBJECT (obj);
644 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
645 callback (obj, size, data);
646 CANARIFY_SIZE (size);
648 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
656 need_remove_object_for_domain (char *start, MonoDomain *domain)
658 if (mono_object_domain (start) == domain) {
659 SGEN_LOG (4, "Need to cleanup object %p", start);
660 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
667 process_object_for_domain_clearing (char *start, MonoDomain *domain)
669 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
670 if (vt->klass == mono_defaults.internal_thread_class)
671 g_assert (mono_object_domain (start) == mono_get_root_domain ());
672 /* The object could be a proxy for an object in the domain
674 #ifndef DISABLE_REMOTING
675 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
676 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
678 /* The server could already have been zeroed out, so
679 we need to check for that, too. */
680 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
681 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
682 ((MonoRealProxy*)start)->unwrapped_server = NULL;
689 clear_domain_process_object (char *obj, MonoDomain *domain)
693 process_object_for_domain_clearing (obj, domain);
694 remove = need_remove_object_for_domain (obj, domain);
696 if (remove && ((MonoObject*)obj)->synchronisation) {
697 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
699 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
706 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
708 if (clear_domain_process_object (obj, domain)) {
709 CANARIFY_SIZE (size);
710 memset (obj, 0, size);
715 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
717 clear_domain_process_object (obj, domain);
721 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
723 if (need_remove_object_for_domain (obj, domain))
724 major_collector.free_non_pinned_object (obj, size);
728 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
730 if (need_remove_object_for_domain (obj, domain))
731 major_collector.free_pinned_object (obj, size);
735 * When appdomains are unloaded we can easily remove objects that have finalizers,
736 * but all the others could still be present in random places on the heap.
737 * We need a sweep to get rid of them even though it's going to be costly
739 * The reason we need to remove them is because we access the vtable and class
740 * structures to know the object size and the reference bitmap: once the domain is
741 * unloaded the point to random memory.
744 mono_gc_clear_domain (MonoDomain * domain)
746 LOSObject *bigobj, *prev;
751 binary_protocol_domain_unload_begin (domain);
755 if (concurrent_collection_in_progress)
756 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
757 g_assert (!concurrent_collection_in_progress);
759 sgen_process_fin_stage_entries ();
760 sgen_process_dislink_stage_entries ();
762 sgen_clear_nursery_fragments ();
764 if (xdomain_checks && domain != mono_get_root_domain ()) {
765 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
766 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
767 sgen_check_for_xdomain_refs ();
770 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
771 to memory returned to the OS.*/
772 null_ephemerons_for_domain (domain);
774 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
775 sgen_null_links_for_domain (domain, i);
777 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
778 sgen_remove_finalizers_for_domain (domain, i);
780 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
781 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
783 /* We need two passes over major and large objects because
784 freeing such objects might give their memory back to the OS
785 (in the case of large objects) or obliterate its vtable
786 (pinned objects with major-copying or pinned and non-pinned
787 objects with major-mark&sweep), but we might need to
788 dereference a pointer from an object to another object if
789 the first object is a proxy. */
790 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
791 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
792 clear_domain_process_object (bigobj->data, domain);
795 for (bigobj = los_object_list; bigobj;) {
796 if (need_remove_object_for_domain (bigobj->data, domain)) {
797 LOSObject *to_free = bigobj;
799 prev->next = bigobj->next;
801 los_object_list = bigobj->next;
802 bigobj = bigobj->next;
803 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
804 sgen_los_free_object (to_free);
808 bigobj = bigobj->next;
810 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
811 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
813 if (domain == mono_get_root_domain ()) {
814 if (G_UNLIKELY (do_pin_stats))
815 sgen_pin_stats_print_class_stats ();
816 sgen_object_layout_dump (stdout);
819 sgen_restart_world (0, NULL);
821 binary_protocol_domain_unload_end (domain);
827 * sgen_add_to_global_remset:
829 * The global remset contains locations which point into newspace after
830 * a minor collection. This can happen if the objects they point to are pinned.
832 * LOCKING: If called from a parallel collector, the global remset
833 * lock must be held. For serial collectors that is not necessary.
836 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
838 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
840 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
842 if (!major_collector.is_concurrent) {
843 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
845 if (current_collection_generation == -1)
846 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
849 if (!object_is_pinned (obj))
850 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");
851 else if (sgen_cement_lookup_or_register (obj))
854 remset.record_pointer (ptr);
856 if (G_UNLIKELY (do_pin_stats))
857 sgen_pin_stats_register_global_remset (obj);
859 SGEN_LOG (8, "Adding global remset for %p", ptr);
860 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
864 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
865 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
866 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
867 vt->klass->name_space, vt->klass->name);
873 * sgen_drain_gray_stack:
875 * Scan objects in the gray stack until the stack is empty. This should be called
876 * frequently after each object is copied, to achieve better locality and cache
879 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
883 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
885 ScanObjectFunc scan_func = ctx.scan_func;
886 GrayQueue *queue = ctx.queue;
890 for (i = 0; i != max_objs; ++i) {
893 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
896 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
897 scan_func (obj, desc, queue);
899 } while (max_objs < 0);
904 * Addresses in the pin queue are already sorted. This function finds
905 * the object header for each address and pins the object. The
906 * addresses must be inside the nursery section. The (start of the)
907 * address array is overwritten with the addresses of the actually
908 * pinned objects. Return the number of pinned objects.
911 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
913 GCMemSection *section = nursery_section;
914 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
915 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
916 void *start_nursery = section->data;
917 void *end_nursery = section->next_data;
922 void *pinning_front = start_nursery;
924 void **definitely_pinned = start;
925 ScanObjectFunc scan_func = ctx.scan_func;
926 SgenGrayQueue *queue = ctx.queue;
928 sgen_nursery_allocator_prepare_for_pinning ();
930 while (start < end) {
931 void *obj_to_pin = NULL;
932 size_t obj_to_pin_size = 0;
937 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
938 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
945 SGEN_LOG (5, "Considering pinning addr %p", addr);
946 /* We've already processed everything up to pinning_front. */
947 if (addr < pinning_front) {
953 * Find the closest scan start <= addr. We might search backward in the
954 * scan_starts array because entries might be NULL. In the worst case we
955 * start at start_nursery.
957 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
958 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
959 search_start = (void*)section->scan_starts [idx];
960 if (!search_start || search_start > addr) {
963 search_start = section->scan_starts [idx];
964 if (search_start && search_start <= addr)
967 if (!search_start || search_start > addr)
968 search_start = start_nursery;
972 * If the pinning front is closer than the scan start we found, start
973 * searching at the front.
975 if (search_start < pinning_front)
976 search_start = pinning_front;
979 * Now addr should be in an object a short distance from search_start.
981 * search_start must point to zeroed mem or point to an object.
987 if (!*(void**)search_start) {
988 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
989 /* The loop condition makes sure we don't overrun addr. */
993 obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
995 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
996 /* This is the object we're looking for. */
997 obj_to_pin = search_start;
998 obj_to_pin_size = obj_size;
1002 /* Skip to the next object */
1003 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
1004 CHECK_CANARY_FOR_OBJECT (search_start);
1005 CANARIFY_SIZE (obj_size);
1006 CANARIFY_SIZE (obj_to_pin_size);
1008 search_start = (void*)((char*)search_start + obj_size);
1009 } while (search_start <= addr);
1011 /* We've searched past the address we were looking for. */
1013 pinning_front = search_start;
1014 goto next_pin_queue_entry;
1018 * We've found an object to pin. It might still be a dummy array, but we
1019 * can advance the pinning front in any case.
1021 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1024 * If this is a dummy array marking the beginning of a nursery
1025 * fragment, we don't pin it.
1027 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1028 goto next_pin_queue_entry;
1031 * Finally - pin the object!
1033 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1035 scan_func (obj_to_pin, desc, queue);
1037 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1038 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1039 binary_protocol_pin (obj_to_pin,
1040 (gpointer)LOAD_VTABLE (obj_to_pin),
1041 safe_object_get_size (obj_to_pin));
1043 #ifdef ENABLE_DTRACE
1044 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1045 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1046 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1047 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1048 sgen_safe_object_get_size (obj_to_pin),
1049 vt->klass->name_space, vt->klass->name, gen);
1053 pin_object (obj_to_pin);
1054 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1055 if (G_UNLIKELY (do_pin_stats))
1056 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1057 definitely_pinned [count] = obj_to_pin;
1061 next_pin_queue_entry:
1065 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1066 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1067 GCRootReport report;
1069 for (idx = 0; idx < count; ++idx)
1070 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1071 notify_gc_roots (&report);
1073 stat_pinned_objects += count;
1078 pin_objects_in_nursery (ScanCopyContext ctx)
1082 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
1085 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1086 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
1091 sgen_pin_object (void *object, GrayQueue *queue)
1093 SGEN_PIN_OBJECT (object);
1094 sgen_pin_stage_ptr (object);
1096 if (G_UNLIKELY (do_pin_stats))
1097 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1099 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1100 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1102 #ifdef ENABLE_DTRACE
1103 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1104 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1105 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1106 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1112 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1116 gboolean major_pinned = FALSE;
1118 if (sgen_ptr_in_nursery (obj)) {
1119 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1120 sgen_pin_object (obj, queue);
1124 major_collector.pin_major_object (obj, queue);
1125 major_pinned = TRUE;
1128 vtable_word = *(mword*)obj;
1129 /*someone else forwarded it, update the pointer and bail out*/
1130 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1131 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1135 /*someone pinned it, nothing to do.*/
1136 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1141 /* Sort the addresses in array in increasing order.
1142 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1145 sgen_sort_addresses (void **array, size_t size)
1150 for (i = 1; i < size; ++i) {
1153 size_t parent = (child - 1) / 2;
1155 if (array [parent] >= array [child])
1158 tmp = array [parent];
1159 array [parent] = array [child];
1160 array [child] = tmp;
1166 for (i = size - 1; i > 0; --i) {
1169 array [i] = array [0];
1175 while (root * 2 + 1 <= end) {
1176 size_t child = root * 2 + 1;
1178 if (child < end && array [child] < array [child + 1])
1180 if (array [root] >= array [child])
1184 array [root] = array [child];
1185 array [child] = tmp;
1193 * Scan the memory between start and end and queue values which could be pointers
1194 * to the area between start_nursery and end_nursery for later consideration.
1195 * Typically used for thread stacks.
1198 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1202 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1203 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1206 while (start < end) {
1207 if (*start >= start_nursery && *start < end_nursery) {
1209 * *start can point to the middle of an object
1210 * note: should we handle pointing at the end of an object?
1211 * pinning in C# code disallows pointing at the end of an object
1212 * but there is some small chance that an optimizing C compiler
1213 * may keep the only reference to an object by pointing
1214 * at the end of it. We ignore this small chance for now.
1215 * Pointers to the end of an object are indistinguishable
1216 * from pointers to the start of the next object in memory
1217 * so if we allow that we'd need to pin two objects...
1218 * We queue the pointer in an array, the
1219 * array will then be sorted and uniqued. This way
1220 * we can coalesce several pinning pointers and it should
1221 * be faster since we'd do a memory scan with increasing
1222 * addresses. Note: we can align the address to the allocation
1223 * alignment, so the unique process is more effective.
1225 mword addr = (mword)*start;
1226 addr &= ~(ALLOC_ALIGN - 1);
1227 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1228 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1229 sgen_pin_stage_ptr ((void*)addr);
1232 if (G_UNLIKELY (do_pin_stats)) {
1233 if (ptr_in_nursery ((void*)addr))
1234 sgen_pin_stats_register_address ((char*)addr, pin_type);
1240 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1244 * The first thing we do in a collection is to identify pinned objects.
1245 * This function considers all the areas of memory that need to be
1246 * conservatively scanned.
1249 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1253 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);
1254 /* objects pinned from the API are inside these roots */
1255 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1256 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1257 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1258 } SGEN_HASH_TABLE_FOREACH_END;
1259 /* now deal with the thread stacks
1260 * in the future we should be able to conservatively scan only:
1261 * *) the cpu registers
1262 * *) the unmanaged stack frames
1263 * *) the _last_ managed stack frame
1264 * *) pointers slots in managed frames
1266 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1270 unpin_objects_from_queue (SgenGrayQueue *queue)
1275 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1278 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1279 SGEN_UNPIN_OBJECT (addr);
1284 CopyOrMarkObjectFunc func;
1286 } UserCopyOrMarkData;
1289 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1291 UserCopyOrMarkData *data = gc_data;
1293 data->func (obj, data->queue);
1297 * The memory area from start_root to end_root contains pointers to objects.
1298 * Their position is precisely described by @desc (this means that the pointer
1299 * can be either NULL or the pointer to the start of an object).
1300 * This functions copies them to to_space updates them.
1302 * This function is not thread-safe!
1305 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1307 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1308 SgenGrayQueue *queue = ctx.queue;
1310 switch (desc & ROOT_DESC_TYPE_MASK) {
1311 case ROOT_DESC_BITMAP:
1312 desc >>= ROOT_DESC_TYPE_SHIFT;
1314 if ((desc & 1) && *start_root) {
1315 copy_func (start_root, queue);
1316 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1317 sgen_drain_gray_stack (-1, ctx);
1323 case ROOT_DESC_COMPLEX: {
1324 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1325 gsize bwords = (*bitmap_data) - 1;
1326 void **start_run = start_root;
1328 while (bwords-- > 0) {
1329 gsize bmap = *bitmap_data++;
1330 void **objptr = start_run;
1332 if ((bmap & 1) && *objptr) {
1333 copy_func (objptr, queue);
1334 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1335 sgen_drain_gray_stack (-1, ctx);
1340 start_run += GC_BITS_PER_WORD;
1344 case ROOT_DESC_USER: {
1345 UserCopyOrMarkData data = { copy_func, queue };
1346 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1347 marker (start_root, single_arg_user_copy_or_mark, &data);
1350 case ROOT_DESC_RUN_LEN:
1351 g_assert_not_reached ();
1353 g_assert_not_reached ();
1358 reset_heap_boundaries (void)
1360 lowest_heap_address = ~(mword)0;
1361 highest_heap_address = 0;
1365 sgen_update_heap_boundaries (mword low, mword high)
1370 old = lowest_heap_address;
1373 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1376 old = highest_heap_address;
1379 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1383 * Allocate and setup the data structures needed to be able to allocate objects
1384 * in the nursery. The nursery is stored in nursery_section.
1387 alloc_nursery (void)
1389 GCMemSection *section;
1394 if (nursery_section)
1396 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1397 /* later we will alloc a larger area for the nursery but only activate
1398 * what we need. The rest will be used as expansion if we have too many pinned
1399 * objects in the existing nursery.
1401 /* FIXME: handle OOM */
1402 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1404 alloc_size = sgen_nursery_size;
1406 /* If there isn't enough space even for the nursery we should simply abort. */
1407 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1409 #ifdef SGEN_ALIGN_NURSERY
1410 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1412 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1414 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1415 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 ());
1416 section->data = section->next_data = data;
1417 section->size = alloc_size;
1418 section->end_data = data + sgen_nursery_size;
1419 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1420 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1421 section->num_scan_start = scan_starts;
1423 nursery_section = section;
1425 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1429 mono_gc_get_nursery (int *shift_bits, size_t *size)
1431 *size = sgen_nursery_size;
1432 #ifdef SGEN_ALIGN_NURSERY
1433 *shift_bits = DEFAULT_NURSERY_BITS;
1437 return sgen_get_nursery_start ();
1441 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1443 SgenThreadInfo *info = mono_thread_info_current ();
1445 /* Could be called from sgen_thread_unregister () with a NULL info */
1448 info->stopped_domain = domain;
1453 mono_gc_precise_stack_mark_enabled (void)
1455 return !conservative_stack_mark;
1459 mono_gc_get_logfile (void)
1461 return gc_debug_file;
1465 report_finalizer_roots_list (FinalizeReadyEntry *list)
1467 GCRootReport report;
1468 FinalizeReadyEntry *fin;
1471 for (fin = list; fin; fin = fin->next) {
1474 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1476 notify_gc_roots (&report);
1480 report_finalizer_roots (void)
1482 report_finalizer_roots_list (fin_ready_list);
1483 report_finalizer_roots_list (critical_fin_list);
1486 static GCRootReport *root_report;
1489 single_arg_report_root (void **obj, void *gc_data)
1492 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1496 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1498 switch (desc & ROOT_DESC_TYPE_MASK) {
1499 case ROOT_DESC_BITMAP:
1500 desc >>= ROOT_DESC_TYPE_SHIFT;
1502 if ((desc & 1) && *start_root) {
1503 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1509 case ROOT_DESC_COMPLEX: {
1510 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1511 gsize bwords = (*bitmap_data) - 1;
1512 void **start_run = start_root;
1514 while (bwords-- > 0) {
1515 gsize bmap = *bitmap_data++;
1516 void **objptr = start_run;
1518 if ((bmap & 1) && *objptr) {
1519 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1524 start_run += GC_BITS_PER_WORD;
1528 case ROOT_DESC_USER: {
1529 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1530 root_report = report;
1531 marker (start_root, single_arg_report_root, NULL);
1534 case ROOT_DESC_RUN_LEN:
1535 g_assert_not_reached ();
1537 g_assert_not_reached ();
1542 report_registered_roots_by_type (int root_type)
1544 GCRootReport report;
1548 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1549 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1550 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1551 } SGEN_HASH_TABLE_FOREACH_END;
1552 notify_gc_roots (&report);
1556 report_registered_roots (void)
1558 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1559 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1563 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1565 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1566 SgenGrayQueue *queue = ctx.queue;
1567 FinalizeReadyEntry *fin;
1569 for (fin = list; fin; fin = fin->next) {
1572 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1573 copy_func (&fin->object, queue);
1578 generation_name (int generation)
1580 switch (generation) {
1581 case GENERATION_NURSERY: return "nursery";
1582 case GENERATION_OLD: return "old";
1583 default: g_assert_not_reached ();
1588 sgen_generation_name (int generation)
1590 return generation_name (generation);
1593 SgenObjectOperations *
1594 sgen_get_current_object_ops (void){
1595 return ¤t_object_ops;
1600 finish_gray_stack (int generation, GrayQueue *queue)
1604 int done_with_ephemerons, ephemeron_rounds = 0;
1605 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1606 ScanObjectFunc scan_func = current_object_ops.scan_object;
1607 ScanCopyContext ctx = { scan_func, copy_func, queue };
1608 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1609 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1612 * We copied all the reachable objects. Now it's the time to copy
1613 * the objects that were not referenced by the roots, but by the copied objects.
1614 * we built a stack of objects pointed to by gray_start: they are
1615 * additional roots and we may add more items as we go.
1616 * We loop until gray_start == gray_objects which means no more objects have
1617 * been added. Note this is iterative: no recursion is involved.
1618 * We need to walk the LO list as well in search of marked big objects
1619 * (use a flag since this is needed only on major collections). We need to loop
1620 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1621 * To achieve better cache locality and cache usage, we drain the gray stack
1622 * frequently, after each object is copied, and just finish the work here.
1624 sgen_drain_gray_stack (-1, ctx);
1626 SGEN_LOG (2, "%s generation done", generation_name (generation));
1629 Reset bridge data, we might have lingering data from a previous collection if this is a major
1630 collection trigged by minor overflow.
1632 We must reset the gathered bridges since their original block might be evacuated due to major
1633 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1635 if (sgen_need_bridge_processing ())
1636 sgen_bridge_reset_data ();
1639 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1640 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1641 * objects that are in fact reachable.
1643 done_with_ephemerons = 0;
1645 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1646 sgen_drain_gray_stack (-1, ctx);
1648 } while (!done_with_ephemerons);
1650 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1652 if (sgen_need_bridge_processing ()) {
1653 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1654 sgen_drain_gray_stack (-1, ctx);
1655 sgen_collect_bridge_objects (generation, ctx);
1656 if (generation == GENERATION_OLD)
1657 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1660 Do the first bridge step here, as the collector liveness state will become useless after that.
1662 An important optimization is to only proccess the possibly dead part of the object graph and skip
1663 over all live objects as we transitively know everything they point must be alive too.
1665 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1667 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1668 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1671 sgen_bridge_processing_stw_step ();
1675 Make sure we drain the gray stack before processing disappearing links and finalizers.
1676 If we don't make sure it is empty we might wrongly see a live object as dead.
1678 sgen_drain_gray_stack (-1, ctx);
1681 We must clear weak links that don't track resurrection before processing object ready for
1682 finalization so they can be cleared before that.
1684 sgen_null_link_in_range (generation, TRUE, ctx);
1685 if (generation == GENERATION_OLD)
1686 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1689 /* walk the finalization queue and move also the objects that need to be
1690 * finalized: use the finalized objects as new roots so the objects they depend
1691 * on are also not reclaimed. As with the roots above, only objects in the nursery
1692 * are marked/copied.
1694 sgen_finalize_in_range (generation, ctx);
1695 if (generation == GENERATION_OLD)
1696 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1697 /* drain the new stack that might have been created */
1698 SGEN_LOG (6, "Precise scan of gray area post fin");
1699 sgen_drain_gray_stack (-1, ctx);
1702 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1704 done_with_ephemerons = 0;
1706 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1707 sgen_drain_gray_stack (-1, ctx);
1709 } while (!done_with_ephemerons);
1712 * Clear ephemeron pairs with unreachable keys.
1713 * We pass the copy func so we can figure out if an array was promoted or not.
1715 clear_unreachable_ephemerons (ctx);
1718 * We clear togglerefs only after all possible chances of revival are done.
1719 * This is semantically more inline with what users expect and it allows for
1720 * user finalizers to correctly interact with TR objects.
1722 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1725 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1728 * handle disappearing links
1729 * Note we do this after checking the finalization queue because if an object
1730 * survives (at least long enough to be finalized) we don't clear the link.
1731 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1732 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1735 g_assert (sgen_gray_object_queue_is_empty (queue));
1737 sgen_null_link_in_range (generation, FALSE, ctx);
1738 if (generation == GENERATION_OLD)
1739 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1740 if (sgen_gray_object_queue_is_empty (queue))
1742 sgen_drain_gray_stack (-1, ctx);
1745 g_assert (sgen_gray_object_queue_is_empty (queue));
1747 sgen_gray_object_queue_trim_free_list (queue);
1751 sgen_check_section_scan_starts (GCMemSection *section)
1754 for (i = 0; i < section->num_scan_start; ++i) {
1755 if (section->scan_starts [i]) {
1756 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1757 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1763 check_scan_starts (void)
1765 if (!do_scan_starts_check)
1767 sgen_check_section_scan_starts (nursery_section);
1768 major_collector.check_scan_starts ();
1772 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1776 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1777 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1778 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1779 } SGEN_HASH_TABLE_FOREACH_END;
1783 sgen_dump_occupied (char *start, char *end, char *section_start)
1785 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1789 sgen_dump_section (GCMemSection *section, const char *type)
1791 char *start = section->data;
1792 char *end = section->data + section->size;
1793 char *occ_start = NULL;
1795 char *old_start = NULL; /* just for debugging */
1797 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1799 while (start < end) {
1803 if (!*(void**)start) {
1805 sgen_dump_occupied (occ_start, start, section->data);
1808 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1811 g_assert (start < section->next_data);
1816 vt = (GCVTable*)LOAD_VTABLE (start);
1819 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1822 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1823 start - section->data,
1824 vt->klass->name_space, vt->klass->name,
1832 sgen_dump_occupied (occ_start, start, section->data);
1834 fprintf (heap_dump_file, "</section>\n");
1838 dump_object (MonoObject *obj, gboolean dump_location)
1840 static char class_name [1024];
1842 MonoClass *class = mono_object_class (obj);
1846 * Python's XML parser is too stupid to parse angle brackets
1847 * in strings, so we just ignore them;
1850 while (class->name [i] && j < sizeof (class_name) - 1) {
1851 if (!strchr ("<>\"", class->name [i]))
1852 class_name [j++] = class->name [i];
1855 g_assert (j < sizeof (class_name));
1858 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1859 class->name_space, class_name,
1860 safe_object_get_size (obj));
1861 if (dump_location) {
1862 const char *location;
1863 if (ptr_in_nursery (obj))
1864 location = "nursery";
1865 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1869 fprintf (heap_dump_file, " location=\"%s\"", location);
1871 fprintf (heap_dump_file, "/>\n");
1875 dump_heap (const char *type, int num, const char *reason)
1880 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1882 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1883 fprintf (heap_dump_file, ">\n");
1884 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1885 sgen_dump_internal_mem_usage (heap_dump_file);
1886 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1887 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1888 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1890 fprintf (heap_dump_file, "<pinned-objects>\n");
1891 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1892 dump_object (list->obj, TRUE);
1893 fprintf (heap_dump_file, "</pinned-objects>\n");
1895 sgen_dump_section (nursery_section, "nursery");
1897 major_collector.dump_heap (heap_dump_file);
1899 fprintf (heap_dump_file, "<los>\n");
1900 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1901 dump_object ((MonoObject*)bigobj->data, FALSE);
1902 fprintf (heap_dump_file, "</los>\n");
1904 fprintf (heap_dump_file, "</collection>\n");
1908 sgen_register_moved_object (void *obj, void *destination)
1910 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1912 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1913 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1914 moved_objects_idx = 0;
1916 moved_objects [moved_objects_idx++] = obj;
1917 moved_objects [moved_objects_idx++] = destination;
1923 static gboolean inited = FALSE;
1928 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1930 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1931 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pinning);
1932 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1933 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1934 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1935 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1936 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1937 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1939 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1940 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pinning);
1941 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1942 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1943 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1944 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1945 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1946 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1947 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1948 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1949 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1950 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_sweep);
1951 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1953 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
1955 #ifdef HEAVY_STATISTICS
1956 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1957 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1958 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1959 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1960 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1961 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1962 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1963 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1964 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1966 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
1967 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
1969 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
1970 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
1971 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
1972 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
1974 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
1975 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
1977 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
1979 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
1980 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
1981 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
1982 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
1984 sgen_nursery_allocator_init_heavy_stats ();
1985 sgen_alloc_init_heavy_stats ();
1993 reset_pinned_from_failed_allocation (void)
1995 bytes_pinned_from_failed_allocation = 0;
1999 sgen_set_pinned_from_failed_allocation (mword objsize)
2001 bytes_pinned_from_failed_allocation += objsize;
2005 sgen_collection_is_concurrent (void)
2007 switch (current_collection_generation) {
2008 case GENERATION_NURSERY:
2010 case GENERATION_OLD:
2011 return concurrent_collection_in_progress;
2013 g_error ("Invalid current generation %d", current_collection_generation);
2018 sgen_concurrent_collection_in_progress (void)
2020 return concurrent_collection_in_progress;
2027 } FinishRememberedSetScanJobData;
2030 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2032 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2034 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2035 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2040 CopyOrMarkObjectFunc copy_or_mark_func;
2041 ScanObjectFunc scan_func;
2045 } ScanFromRegisteredRootsJobData;
2048 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2050 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2051 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2052 sgen_workers_get_job_gray_queue (worker_data) };
2054 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2055 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2062 } ScanThreadDataJobData;
2065 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2067 ScanThreadDataJobData *job_data = job_data_untyped;
2069 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2070 sgen_workers_get_job_gray_queue (worker_data));
2071 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2075 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2077 FinalizeReadyEntry *list = job_data_untyped;
2078 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2080 scan_finalizer_entries (list, ctx);
2084 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2086 g_assert (concurrent_collection_in_progress);
2087 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2091 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2093 g_assert (concurrent_collection_in_progress);
2094 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2098 verify_scan_starts (char *start, char *end)
2102 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2103 char *addr = nursery_section->scan_starts [i];
2104 if (addr > start && addr < end)
2105 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2110 verify_nursery (void)
2112 char *start, *end, *cur, *hole_start;
2114 if (!do_verify_nursery)
2117 if (nursery_canaries_enabled ())
2118 SGEN_LOG (1, "Checking nursery canaries...");
2120 /*This cleans up unused fragments */
2121 sgen_nursery_allocator_prepare_for_pinning ();
2123 hole_start = start = cur = sgen_get_nursery_start ();
2124 end = sgen_get_nursery_end ();
2129 if (!*(void**)cur) {
2130 cur += sizeof (void*);
2134 if (object_is_forwarded (cur))
2135 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2136 else if (object_is_pinned (cur))
2137 SGEN_LOG (1, "PINNED OBJ %p", cur);
2139 ss = safe_object_get_size ((MonoObject*)cur);
2140 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2141 verify_scan_starts (cur, cur + size);
2142 if (do_dump_nursery_content) {
2143 if (cur > hole_start)
2144 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2145 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 ());
2147 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2148 CHECK_CANARY_FOR_OBJECT (cur);
2149 CANARIFY_SIZE (size);
2157 * Checks that no objects in the nursery are fowarded or pinned. This
2158 * is a precondition to restarting the mutator while doing a
2159 * concurrent collection. Note that we don't clear fragments because
2160 * we depend on that having happened earlier.
2163 check_nursery_is_clean (void)
2165 char *start, *end, *cur;
2167 start = cur = sgen_get_nursery_start ();
2168 end = sgen_get_nursery_end ();
2173 if (!*(void**)cur) {
2174 cur += sizeof (void*);
2178 g_assert (!object_is_forwarded (cur));
2179 g_assert (!object_is_pinned (cur));
2181 ss = safe_object_get_size ((MonoObject*)cur);
2182 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2183 verify_scan_starts (cur, cur + size);
2190 init_gray_queue (void)
2192 if (sgen_collection_is_concurrent ()) {
2193 sgen_workers_init_distribute_gray_queue ();
2194 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2195 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2197 sgen_gray_object_queue_init (&gray_queue, NULL);
2202 * Collect objects in the nursery. Returns whether to trigger a major
2206 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2208 gboolean needs_major;
2209 size_t max_garbage_amount;
2211 FinishRememberedSetScanJobData *frssjd;
2212 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2213 ScanThreadDataJobData *stdjd;
2214 mword fragment_total;
2215 ScanCopyContext ctx;
2219 if (disable_minor_collections)
2222 TV_GETTIME (last_minor_collection_start_tv);
2223 atv = last_minor_collection_start_tv;
2225 MONO_GC_BEGIN (GENERATION_NURSERY);
2226 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2230 #ifndef DISABLE_PERFCOUNTERS
2231 mono_perfcounters->gc_collections0++;
2234 current_collection_generation = GENERATION_NURSERY;
2235 current_object_ops = sgen_minor_collector.serial_ops;
2237 reset_pinned_from_failed_allocation ();
2239 check_scan_starts ();
2241 sgen_nursery_alloc_prepare_for_minor ();
2245 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2246 /* FIXME: optimize later to use the higher address where an object can be present */
2247 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2249 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 ()));
2250 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2251 g_assert (nursery_section->size >= max_garbage_amount);
2253 /* world must be stopped already */
2255 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2257 if (xdomain_checks) {
2258 sgen_clear_nursery_fragments ();
2259 sgen_check_for_xdomain_refs ();
2262 nursery_section->next_data = nursery_next;
2264 major_collector.start_nursery_collection ();
2266 sgen_memgov_minor_collection_start ();
2270 gc_stats.minor_gc_count ++;
2272 if (whole_heap_check_before_collection) {
2273 sgen_clear_nursery_fragments ();
2274 sgen_check_whole_heap (finish_up_concurrent_mark);
2276 if (consistency_check_at_minor_collection)
2277 sgen_check_consistency ();
2279 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2281 sgen_process_fin_stage_entries ();
2282 sgen_process_dislink_stage_entries ();
2284 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2286 /* pin from pinned handles */
2287 sgen_init_pinning ();
2288 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2289 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2290 /* pin cemented objects */
2291 sgen_pin_cemented_objects ();
2292 /* identify pinned objects */
2293 sgen_optimize_pin_queue ();
2294 sgen_pinning_setup_section (nursery_section);
2295 ctx.scan_func = NULL;
2296 ctx.copy_func = NULL;
2297 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2298 pin_objects_in_nursery (ctx);
2299 sgen_pinning_trim_queue_to_section (nursery_section);
2302 time_minor_pinning += TV_ELAPSED (btv, atv);
2303 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2304 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2306 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2308 sgen_workers_start_all_workers ();
2310 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2311 frssjd->heap_start = sgen_get_nursery_start ();
2312 frssjd->heap_end = nursery_next;
2313 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2315 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2317 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2318 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2320 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2322 /* FIXME: why is this here? */
2323 ctx.scan_func = current_object_ops.scan_object;
2324 ctx.copy_func = NULL;
2325 ctx.queue = &gray_queue;
2326 sgen_drain_gray_stack (-1, ctx);
2328 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2329 report_registered_roots ();
2330 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2331 report_finalizer_roots ();
2333 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2335 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2337 /* registered roots, this includes static fields */
2338 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2339 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2340 scrrjd_normal->scan_func = current_object_ops.scan_object;
2341 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2342 scrrjd_normal->heap_end = nursery_next;
2343 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2344 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2346 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2347 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2348 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2349 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2350 scrrjd_wbarrier->heap_end = nursery_next;
2351 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2352 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2355 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2357 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2360 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2361 stdjd->heap_start = sgen_get_nursery_start ();
2362 stdjd->heap_end = nursery_next;
2363 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2366 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2369 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2371 g_assert (!sgen_collection_is_concurrent ());
2373 /* Scan the list of objects ready for finalization. If */
2374 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2375 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2377 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2379 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2381 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2382 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2384 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2387 * The (single-threaded) finalization code might have done
2388 * some copying/marking so we can only reset the GC thread's
2389 * worker data here instead of earlier when we joined the
2392 sgen_workers_reset_data ();
2394 if (objects_pinned) {
2395 sgen_optimize_pin_queue ();
2396 sgen_pinning_setup_section (nursery_section);
2399 /* walk the pin_queue, build up the fragment list of free memory, unmark
2400 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2403 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2404 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2405 if (!fragment_total)
2408 /* Clear TLABs for all threads */
2409 sgen_clear_tlabs ();
2411 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2413 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2414 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2416 if (consistency_check_at_minor_collection)
2417 sgen_check_major_refs ();
2419 major_collector.finish_nursery_collection ();
2421 TV_GETTIME (last_minor_collection_end_tv);
2422 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2425 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2427 /* prepare the pin queue for the next collection */
2428 sgen_finish_pinning ();
2429 if (fin_ready_list || critical_fin_list) {
2430 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2431 mono_gc_finalize_notify ();
2433 sgen_pin_stats_reset ();
2434 /* clear cemented hash */
2435 sgen_cement_clear_below_threshold ();
2437 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2439 remset.finish_minor_collection ();
2441 check_scan_starts ();
2443 binary_protocol_flush_buffers (FALSE);
2445 sgen_memgov_minor_collection_end ();
2447 /*objects are late pinned because of lack of memory, so a major is a good call*/
2448 needs_major = objects_pinned > 0;
2449 current_collection_generation = -1;
2452 MONO_GC_END (GENERATION_NURSERY);
2453 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY);
2455 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2456 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2458 if (concurrent_collection_in_progress)
2459 sgen_workers_signal_finish_nursery_collection ();
2465 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2468 * This is called on all objects in the nursery, including pinned ones, so we need
2469 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2471 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2475 scan_nursery_objects (ScanCopyContext ctx)
2477 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2478 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2482 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2487 /* FIXME: only use these values for the precise scan
2488 * note that to_space pointers should be excluded anyway...
2490 char *heap_start = NULL;
2491 char *heap_end = (char*)-1;
2492 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2493 GCRootReport root_report = { 0 };
2494 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2495 ScanThreadDataJobData *stdjd;
2496 ScanCopyContext ctx;
2498 if (concurrent_collection_in_progress) {
2499 /*This cleans up unused fragments */
2500 sgen_nursery_allocator_prepare_for_pinning ();
2502 if (do_concurrent_checks)
2503 check_nursery_is_clean ();
2505 /* The concurrent collector doesn't touch the nursery. */
2506 sgen_nursery_alloc_prepare_for_major ();
2513 /* Pinning depends on this */
2514 sgen_clear_nursery_fragments ();
2516 if (whole_heap_check_before_collection)
2517 sgen_check_whole_heap (finish_up_concurrent_mark);
2520 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2522 if (!sgen_collection_is_concurrent ())
2523 nursery_section->next_data = sgen_get_nursery_end ();
2524 /* we should also coalesce scanning from sections close to each other
2525 * and deal with pointers outside of the sections later.
2529 *major_collector.have_swept = FALSE;
2531 if (xdomain_checks) {
2532 sgen_clear_nursery_fragments ();
2533 sgen_check_for_xdomain_refs ();
2536 if (!concurrent_collection_in_progress) {
2537 /* Remsets are not useful for a major collection */
2538 remset.prepare_for_major_collection ();
2541 sgen_process_fin_stage_entries ();
2542 sgen_process_dislink_stage_entries ();
2545 sgen_init_pinning ();
2546 SGEN_LOG (6, "Collecting pinned addresses");
2547 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2549 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2550 if (major_collector.is_concurrent) {
2552 * The concurrent major collector cannot evict
2553 * yet, so we need to pin cemented objects to
2554 * not break some asserts.
2556 * FIXME: We could evict now!
2558 sgen_pin_cemented_objects ();
2561 if (!concurrent_collection_in_progress)
2562 sgen_cement_reset ();
2565 sgen_optimize_pin_queue ();
2568 * The concurrent collector doesn't move objects, neither on
2569 * the major heap nor in the nursery, so we can mark even
2570 * before pinning has finished. For the non-concurrent
2571 * collector we start the workers after pinning.
2573 if (concurrent_collection_in_progress)
2574 sgen_workers_start_all_workers ();
2577 * pin_queue now contains all candidate pointers, sorted and
2578 * uniqued. We must do two passes now to figure out which
2579 * objects are pinned.
2581 * The first is to find within the pin_queue the area for each
2582 * section. This requires that the pin_queue be sorted. We
2583 * also process the LOS objects and pinned chunks here.
2585 * The second, destructive, pass is to reduce the section
2586 * areas to pointers to the actually pinned objects.
2588 SGEN_LOG (6, "Pinning from sections");
2589 /* first pass for the sections */
2590 sgen_find_section_pin_queue_start_end (nursery_section);
2591 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2592 /* identify possible pointers to the insize of large objects */
2593 SGEN_LOG (6, "Pinning from large objects");
2594 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2596 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2597 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2599 #ifdef ENABLE_DTRACE
2600 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2601 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2602 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2606 if (sgen_los_object_is_pinned (bigobj->data)) {
2607 g_assert (finish_up_concurrent_mark);
2610 sgen_los_pin_object (bigobj->data);
2611 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2612 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2613 if (G_UNLIKELY (do_pin_stats))
2614 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2615 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));
2618 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2622 notify_gc_roots (&root_report);
2623 /* second pass for the sections */
2624 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2625 ctx.copy_func = NULL;
2626 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2629 * Concurrent mark never follows references into the nursery.
2630 * In the start and finish pauses we must scan live nursery
2631 * objects, though. We could simply scan all nursery objects,
2632 * but that would be conservative. The easiest way is to do a
2633 * nursery collection, which copies all live nursery objects
2634 * (except pinned ones, with the simple nursery) to the major
2635 * heap. Scanning the mod union table later will then scan
2636 * those promoted objects, provided they're reachable. Pinned
2637 * objects in the nursery - which we can trivially find in the
2638 * pinning queue - are treated as roots in the mark pauses.
2640 * The split nursery complicates the latter part because
2641 * non-pinned objects can survive in the nursery. That's why
2642 * we need to do a full front-to-back scan of the nursery,
2643 * marking all objects.
2645 * Non-concurrent mark evacuates from the nursery, so it's
2646 * sufficient to just scan pinned nursery objects.
2648 if (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 ();
2667 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2668 main_gc_thread = mono_native_thread_self ();
2671 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2672 report_registered_roots ();
2674 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2676 /* registered roots, this includes static fields */
2677 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2678 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2679 scrrjd_normal->scan_func = current_object_ops.scan_object;
2680 scrrjd_normal->heap_start = heap_start;
2681 scrrjd_normal->heap_end = heap_end;
2682 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2683 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2685 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2686 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2687 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2688 scrrjd_wbarrier->heap_start = heap_start;
2689 scrrjd_wbarrier->heap_end = heap_end;
2690 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2691 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2694 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2697 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2698 stdjd->heap_start = heap_start;
2699 stdjd->heap_end = heap_end;
2700 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2703 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2706 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2708 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2709 report_finalizer_roots ();
2711 /* scan the list of objects ready for finalization */
2712 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2713 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2715 if (scan_mod_union) {
2716 g_assert (finish_up_concurrent_mark);
2718 /* Mod union card table */
2719 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2720 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2724 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2725 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2728 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2730 if (concurrent_collection_in_progress) {
2731 /* prepare the pin queue for the next collection */
2732 sgen_finish_pinning ();
2734 sgen_pin_stats_reset ();
2736 if (do_concurrent_checks)
2737 check_nursery_is_clean ();
2742 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2744 MONO_GC_BEGIN (GENERATION_OLD);
2745 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2747 current_collection_generation = GENERATION_OLD;
2748 #ifndef DISABLE_PERFCOUNTERS
2749 mono_perfcounters->gc_collections1++;
2752 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2755 g_assert (major_collector.is_concurrent);
2756 concurrent_collection_in_progress = TRUE;
2758 sgen_cement_concurrent_start ();
2760 current_object_ops = major_collector.major_concurrent_ops;
2762 current_object_ops = major_collector.major_ops;
2765 reset_pinned_from_failed_allocation ();
2767 sgen_memgov_major_collection_start ();
2769 //count_ref_nonref_objs ();
2770 //consistency_check ();
2772 check_scan_starts ();
2775 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2776 gc_stats.major_gc_count ++;
2778 if (major_collector.start_major_collection)
2779 major_collector.start_major_collection ();
2781 major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
2785 wait_for_workers_to_finish (void)
2787 while (!sgen_workers_all_done ())
2794 if (concurrent_collection_in_progress) {
2795 gray_queue_redirect (&gray_queue);
2796 sgen_workers_join ();
2799 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2801 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2802 main_gc_thread = NULL;
2807 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union)
2809 LOSObject *bigobj, *prevbo;
2815 if (concurrent_collection_in_progress)
2818 if (concurrent_collection_in_progress) {
2819 current_object_ops = major_collector.major_concurrent_ops;
2821 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
2824 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2826 if (do_concurrent_checks)
2827 check_nursery_is_clean ();
2829 current_object_ops = major_collector.major_ops;
2833 * The workers have stopped so we need to finish gray queue
2834 * work that might result from finalization in the main GC
2835 * thread. Redirection must therefore be turned off.
2837 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2838 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2840 /* all the objects in the heap */
2841 finish_gray_stack (GENERATION_OLD, &gray_queue);
2843 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2845 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2848 * The (single-threaded) finalization code might have done
2849 * some copying/marking so we can only reset the GC thread's
2850 * worker data here instead of earlier when we joined the
2853 sgen_workers_reset_data ();
2855 if (objects_pinned) {
2856 g_assert (!concurrent_collection_in_progress);
2859 * This is slow, but we just OOM'd.
2861 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2862 * queue is laid out at this point.
2864 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2866 * We need to reestablish all pinned nursery objects in the pin queue
2867 * because they're needed for fragment creation. Unpinning happens by
2868 * walking the whole queue, so it's not necessary to reestablish where major
2869 * heap block pins are - all we care is that they're still in there
2872 sgen_optimize_pin_queue ();
2873 sgen_find_section_pin_queue_start_end (nursery_section);
2877 reset_heap_boundaries ();
2878 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2880 if (check_mark_bits_after_major_collection)
2881 sgen_check_major_heap_marked ();
2883 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2885 /* sweep the big objects list */
2887 for (bigobj = los_object_list; bigobj;) {
2888 g_assert (!object_is_pinned (bigobj->data));
2889 if (sgen_los_object_is_pinned (bigobj->data)) {
2890 sgen_los_unpin_object (bigobj->data);
2891 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2894 /* not referenced anywhere, so we can free it */
2896 prevbo->next = bigobj->next;
2898 los_object_list = bigobj->next;
2900 bigobj = bigobj->next;
2901 sgen_los_free_object (to_free);
2905 bigobj = bigobj->next;
2909 time_major_free_bigobjs += TV_ELAPSED (atv, btv);
2914 time_major_los_sweep += TV_ELAPSED (btv, atv);
2916 major_collector.sweep ();
2918 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2921 time_major_sweep += TV_ELAPSED (atv, btv);
2923 if (!concurrent_collection_in_progress) {
2924 /* walk the pin_queue, build up the fragment list of free memory, unmark
2925 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2928 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2931 /* prepare the pin queue for the next collection */
2932 sgen_finish_pinning ();
2934 /* Clear TLABs for all threads */
2935 sgen_clear_tlabs ();
2937 sgen_pin_stats_reset ();
2940 if (concurrent_collection_in_progress)
2941 sgen_cement_concurrent_finish ();
2942 sgen_cement_clear_below_threshold ();
2945 time_major_fragment_creation += TV_ELAPSED (btv, atv);
2948 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2950 if (fin_ready_list || critical_fin_list) {
2951 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2952 mono_gc_finalize_notify ();
2955 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2957 sgen_memgov_major_collection_end ();
2958 current_collection_generation = -1;
2960 major_collector.finish_major_collection ();
2962 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2964 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2965 if (concurrent_collection_in_progress)
2966 concurrent_collection_in_progress = FALSE;
2968 check_scan_starts ();
2970 binary_protocol_flush_buffers (FALSE);
2972 //consistency_check ();
2974 MONO_GC_END (GENERATION_OLD);
2975 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD);
2979 major_do_collection (const char *reason)
2981 TV_DECLARE (time_start);
2982 TV_DECLARE (time_end);
2983 size_t old_next_pin_slot;
2985 if (disable_major_collections)
2988 if (major_collector.get_and_reset_num_major_objects_marked) {
2989 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2990 g_assert (!num_marked);
2993 /* world must be stopped already */
2994 TV_GETTIME (time_start);
2996 major_start_collection (FALSE, &old_next_pin_slot);
2997 major_finish_collection (reason, old_next_pin_slot, FALSE);
2999 TV_GETTIME (time_end);
3000 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3002 /* FIXME: also report this to the user, preferably in gc-end. */
3003 if (major_collector.get_and_reset_num_major_objects_marked)
3004 major_collector.get_and_reset_num_major_objects_marked ();
3006 return bytes_pinned_from_failed_allocation > 0;
3010 major_start_concurrent_collection (const char *reason)
3012 TV_DECLARE (time_start);
3013 TV_DECLARE (time_end);
3014 long long num_objects_marked;
3016 if (disable_major_collections)
3019 TV_GETTIME (time_start);
3020 SGEN_TV_GETTIME (time_major_conc_collection_start);
3022 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3023 g_assert (num_objects_marked == 0);
3025 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3026 binary_protocol_concurrent_start ();
3028 // FIXME: store reason and pass it when finishing
3029 major_start_collection (TRUE, NULL);
3031 gray_queue_redirect (&gray_queue);
3032 sgen_workers_wait_for_jobs_finished ();
3034 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3035 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3037 TV_GETTIME (time_end);
3038 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3040 current_collection_generation = -1;
3044 major_update_or_finish_concurrent_collection (gboolean force_finish)
3046 TV_DECLARE (total_start);
3047 TV_DECLARE (total_end);
3048 SgenGrayQueue unpin_queue;
3049 memset (&unpin_queue, 0, sizeof (unpin_queue));
3051 TV_GETTIME (total_start);
3053 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3054 binary_protocol_concurrent_update_finish ();
3056 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3058 if (!force_finish && !sgen_workers_all_done ()) {
3059 sgen_workers_signal_start_nursery_collection_and_wait ();
3061 major_collector.update_cardtable_mod_union ();
3062 sgen_los_update_cardtable_mod_union ();
3064 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3066 TV_GETTIME (total_end);
3067 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3073 * The major collector can add global remsets which are processed in the finishing
3074 * nursery collection, below. That implies that the workers must have finished
3075 * marking before the nursery collection is allowed to run, otherwise we might miss
3078 wait_for_workers_to_finish ();
3080 SGEN_TV_GETTIME (time_major_conc_collection_end);
3081 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3083 major_collector.update_cardtable_mod_union ();
3084 sgen_los_update_cardtable_mod_union ();
3086 collect_nursery (&unpin_queue, TRUE);
3088 if (mod_union_consistency_check)
3089 sgen_check_mod_union_consistency ();
3091 current_collection_generation = GENERATION_OLD;
3092 major_finish_collection ("finishing", -1, TRUE);
3094 if (whole_heap_check_before_collection)
3095 sgen_check_whole_heap (FALSE);
3097 unpin_objects_from_queue (&unpin_queue);
3098 sgen_gray_object_queue_deinit (&unpin_queue);
3100 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3102 TV_GETTIME (total_end);
3103 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3105 current_collection_generation = -1;
3111 * Ensure an allocation request for @size will succeed by freeing enough memory.
3113 * LOCKING: The GC lock MUST be held.
3116 sgen_ensure_free_space (size_t size)
3118 int generation_to_collect = -1;
3119 const char *reason = NULL;
3122 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3123 if (sgen_need_major_collection (size)) {
3124 reason = "LOS overflow";
3125 generation_to_collect = GENERATION_OLD;
3128 if (degraded_mode) {
3129 if (sgen_need_major_collection (size)) {
3130 reason = "Degraded mode overflow";
3131 generation_to_collect = GENERATION_OLD;
3133 } else if (sgen_need_major_collection (size)) {
3134 reason = "Minor allowance";
3135 generation_to_collect = GENERATION_OLD;
3137 generation_to_collect = GENERATION_NURSERY;
3138 reason = "Nursery full";
3142 if (generation_to_collect == -1) {
3143 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3144 generation_to_collect = GENERATION_OLD;
3145 reason = "Finish concurrent collection";
3149 if (generation_to_collect == -1)
3151 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3155 * LOCKING: Assumes the GC lock is held.
3158 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3160 TV_DECLARE (gc_end);
3161 TV_DECLARE (gc_total_start);
3162 TV_DECLARE (gc_total_end);
3163 GGTimingInfo infos [2];
3164 int overflow_generation_to_collect = -1;
3165 int oldest_generation_collected = generation_to_collect;
3166 const char *overflow_reason = NULL;
3168 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3170 binary_protocol_collection_force (generation_to_collect);
3172 g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3174 memset (infos, 0, sizeof (infos));
3175 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3177 infos [0].generation = generation_to_collect;
3178 infos [0].reason = reason;
3179 infos [0].is_overflow = FALSE;
3180 TV_GETTIME (infos [0].total_time);
3181 infos [1].generation = -1;
3183 sgen_stop_world (generation_to_collect);
3185 TV_GETTIME (gc_total_start);
3187 if (concurrent_collection_in_progress) {
3188 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3189 oldest_generation_collected = GENERATION_OLD;
3192 if (generation_to_collect == GENERATION_OLD)
3195 if (generation_to_collect == GENERATION_OLD &&
3196 allow_synchronous_major &&
3197 major_collector.want_synchronous_collection &&
3198 *major_collector.want_synchronous_collection) {
3199 wait_to_finish = TRUE;
3203 //FIXME extract overflow reason
3204 if (generation_to_collect == GENERATION_NURSERY) {
3205 if (collect_nursery (NULL, FALSE)) {
3206 overflow_generation_to_collect = GENERATION_OLD;
3207 overflow_reason = "Minor overflow";
3210 if (major_collector.is_concurrent) {
3211 g_assert (!concurrent_collection_in_progress);
3212 if (!wait_to_finish)
3213 collect_nursery (NULL, FALSE);
3216 if (major_collector.is_concurrent && !wait_to_finish) {
3217 major_start_concurrent_collection (reason);
3218 // FIXME: set infos[0] properly
3221 if (major_do_collection (reason)) {
3222 overflow_generation_to_collect = GENERATION_NURSERY;
3223 overflow_reason = "Excessive pinning";
3228 TV_GETTIME (gc_end);
3229 infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3232 if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3233 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3234 infos [1].generation = overflow_generation_to_collect;
3235 infos [1].reason = overflow_reason;
3236 infos [1].is_overflow = TRUE;
3237 infos [1].total_time = gc_end;
3239 if (overflow_generation_to_collect == GENERATION_NURSERY)
3240 collect_nursery (NULL, FALSE);
3242 major_do_collection (overflow_reason);
3244 TV_GETTIME (gc_end);
3245 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3247 /* keep events symmetric */
3248 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3250 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3253 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3255 /* this also sets the proper pointers for the next allocation */
3256 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3257 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3258 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3259 sgen_dump_pin_queue ();
3264 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3266 TV_GETTIME (gc_total_end);
3267 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3269 sgen_restart_world (oldest_generation_collected, infos);
3271 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3275 * ######################################################################
3276 * ######## Memory allocation from the OS
3277 * ######################################################################
3278 * This section of code deals with getting memory from the OS and
3279 * allocating memory for GC-internal data structures.
3280 * Internal memory can be handled with a freelist for small objects.
3286 G_GNUC_UNUSED static void
3287 report_internal_mem_usage (void)
3289 printf ("Internal memory usage:\n");
3290 sgen_report_internal_mem_usage ();
3291 printf ("Pinned memory usage:\n");
3292 major_collector.report_pinned_memory_usage ();
3296 * ######################################################################
3297 * ######## Finalization support
3298 * ######################################################################
3301 static inline gboolean
3302 sgen_major_is_object_alive (void *object)
3306 /* Oldgen objects can be pinned and forwarded too */
3307 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3311 * FIXME: major_collector.is_object_live() also calculates the
3312 * size. Avoid the double calculation.
3314 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3315 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3316 return sgen_los_object_is_pinned (object);
3318 return major_collector.is_object_live (object);
3322 * If the object has been forwarded it means it's still referenced from a root.
3323 * If it is pinned it's still alive as well.
3324 * A LOS object is only alive if we have pinned it.
3325 * Return TRUE if @obj is ready to be finalized.
3327 static inline gboolean
3328 sgen_is_object_alive (void *object)
3330 if (ptr_in_nursery (object))
3331 return sgen_nursery_is_object_alive (object);
3333 return sgen_major_is_object_alive (object);
3337 * This function returns true if @object is either alive or it belongs to the old gen
3338 * and we're currently doing a minor collection.
3341 sgen_is_object_alive_for_current_gen (char *object)
3343 if (ptr_in_nursery (object))
3344 return sgen_nursery_is_object_alive (object);
3346 if (current_collection_generation == GENERATION_NURSERY)
3349 return sgen_major_is_object_alive (object);
3353 * This function returns true if @object is either alive and belongs to the
3354 * current collection - major collections are full heap, so old gen objects
3355 * are never alive during a minor collection.
3358 sgen_is_object_alive_and_on_current_collection (char *object)
3360 if (ptr_in_nursery (object))
3361 return sgen_nursery_is_object_alive (object);
3363 if (current_collection_generation == GENERATION_NURSERY)
3366 return sgen_major_is_object_alive (object);
3371 sgen_gc_is_object_ready_for_finalization (void *object)
3373 return !sgen_is_object_alive (object);
3377 has_critical_finalizer (MonoObject *obj)
3381 if (!mono_defaults.critical_finalizer_object)
3384 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3386 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3390 is_finalization_aware (MonoObject *obj)
3392 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3393 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3397 sgen_queue_finalization_entry (MonoObject *obj)
3399 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3400 gboolean critical = has_critical_finalizer (obj);
3401 entry->object = obj;
3403 entry->next = critical_fin_list;
3404 critical_fin_list = entry;
3406 entry->next = fin_ready_list;
3407 fin_ready_list = entry;
3410 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3411 fin_callbacks.object_queued_for_finalization (obj);
3413 #ifdef ENABLE_DTRACE
3414 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3415 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3416 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3417 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3418 vt->klass->name_space, vt->klass->name, gen, critical);
3424 sgen_object_is_live (void *obj)
3426 return sgen_is_object_alive_and_on_current_collection (obj);
3429 /* LOCKING: requires that the GC lock is held */
3431 null_ephemerons_for_domain (MonoDomain *domain)
3433 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3436 MonoObject *object = (MonoObject*)current->array;
3438 if (object && !object->vtable) {
3439 EphemeronLinkNode *tmp = current;
3442 prev->next = current->next;
3444 ephemeron_list = current->next;
3446 current = current->next;
3447 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3450 current = current->next;
3455 /* LOCKING: requires that the GC lock is held */
3457 clear_unreachable_ephemerons (ScanCopyContext ctx)
3459 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3460 GrayQueue *queue = ctx.queue;
3461 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3463 Ephemeron *cur, *array_end;
3467 char *object = current->array;
3469 if (!sgen_is_object_alive_for_current_gen (object)) {
3470 EphemeronLinkNode *tmp = current;
3472 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3475 prev->next = current->next;
3477 ephemeron_list = current->next;
3479 current = current->next;
3480 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3485 copy_func ((void**)&object, queue);
3486 current->array = object;
3488 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3490 array = (MonoArray*)object;
3491 cur = mono_array_addr (array, Ephemeron, 0);
3492 array_end = cur + mono_array_length_fast (array);
3493 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3495 for (; cur < array_end; ++cur) {
3496 char *key = (char*)cur->key;
3498 if (!key || key == tombstone)
3501 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3502 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3503 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3505 if (!sgen_is_object_alive_for_current_gen (key)) {
3506 cur->key = tombstone;
3512 current = current->next;
3517 LOCKING: requires that the GC lock is held
3519 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3522 mark_ephemerons_in_range (ScanCopyContext ctx)
3524 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3525 GrayQueue *queue = ctx.queue;
3526 int nothing_marked = 1;
3527 EphemeronLinkNode *current = ephemeron_list;
3529 Ephemeron *cur, *array_end;
3532 for (current = ephemeron_list; current; current = current->next) {
3533 char *object = current->array;
3534 SGEN_LOG (5, "Ephemeron array at %p", object);
3536 /*It has to be alive*/
3537 if (!sgen_is_object_alive_for_current_gen (object)) {
3538 SGEN_LOG (5, "\tnot reachable");
3542 copy_func ((void**)&object, queue);
3544 array = (MonoArray*)object;
3545 cur = mono_array_addr (array, Ephemeron, 0);
3546 array_end = cur + mono_array_length_fast (array);
3547 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3549 for (; cur < array_end; ++cur) {
3550 char *key = cur->key;
3552 if (!key || key == tombstone)
3555 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3556 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3557 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3559 if (sgen_is_object_alive_for_current_gen (key)) {
3560 char *value = cur->value;
3562 copy_func ((void**)&cur->key, queue);
3564 if (!sgen_is_object_alive_for_current_gen (value))
3566 copy_func ((void**)&cur->value, queue);
3572 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3573 return nothing_marked;
3577 mono_gc_invoke_finalizers (void)
3579 FinalizeReadyEntry *entry = NULL;
3580 gboolean entry_is_critical = FALSE;
3583 /* FIXME: batch to reduce lock contention */
3584 while (fin_ready_list || critical_fin_list) {
3588 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3590 /* We have finalized entry in the last
3591 interation, now we need to remove it from
3594 *list = entry->next;
3596 FinalizeReadyEntry *e = *list;
3597 while (e->next != entry)
3599 e->next = entry->next;
3601 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3605 /* Now look for the first non-null entry. */
3606 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3609 entry_is_critical = FALSE;
3611 entry_is_critical = TRUE;
3612 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3617 g_assert (entry->object);
3618 num_ready_finalizers--;
3619 obj = entry->object;
3620 entry->object = NULL;
3621 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3629 g_assert (entry->object == NULL);
3631 /* the object is on the stack so it is pinned */
3632 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3633 mono_gc_run_finalize (obj, NULL);
3640 mono_gc_pending_finalizers (void)
3642 return fin_ready_list || critical_fin_list;
3646 * ######################################################################
3647 * ######## registered roots support
3648 * ######################################################################
3652 * We do not coalesce roots.
3655 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3657 RootRecord new_root;
3660 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3661 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3662 /* we allow changing the size and the descriptor (for thread statics etc) */
3664 size_t old_size = root->end_root - start;
3665 root->end_root = start + size;
3666 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3667 ((root->root_desc == 0) && (descr == NULL)));
3668 root->root_desc = (mword)descr;
3670 roots_size -= old_size;
3676 new_root.end_root = start + size;
3677 new_root.root_desc = (mword)descr;
3679 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3682 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);
3689 mono_gc_register_root (char *start, size_t size, void *descr)
3691 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3695 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3697 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3701 mono_gc_deregister_root (char* addr)
3707 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3708 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3709 roots_size -= (root.end_root - addr);
3715 * ######################################################################
3716 * ######## Thread handling (stop/start code)
3717 * ######################################################################
3720 unsigned int sgen_global_stop_count = 0;
3723 sgen_get_current_collection_generation (void)
3725 return current_collection_generation;
3729 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3731 gc_callbacks = *callbacks;
3735 mono_gc_get_gc_callbacks ()
3737 return &gc_callbacks;
3740 /* Variables holding start/end nursery so it won't have to be passed at every call */
3741 static void *scan_area_arg_start, *scan_area_arg_end;
3744 mono_gc_conservatively_scan_area (void *start, void *end)
3746 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3750 mono_gc_scan_object (void *obj, void *gc_data)
3752 UserCopyOrMarkData *data = gc_data;
3753 current_object_ops.copy_or_mark_object (&obj, data->queue);
3758 * Mark from thread stacks and registers.
3761 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3763 SgenThreadInfo *info;
3765 scan_area_arg_start = start_nursery;
3766 scan_area_arg_end = end_nursery;
3768 FOREACH_THREAD (info) {
3770 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);
3773 if (info->gc_disabled) {
3774 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);
3777 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3778 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));
3781 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 ());
3782 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3783 UserCopyOrMarkData data = { NULL, queue };
3784 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3785 } else if (!precise) {
3786 if (!conservative_stack_mark) {
3787 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3788 conservative_stack_mark = TRUE;
3790 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3795 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3796 start_nursery, end_nursery, PIN_TYPE_STACK);
3798 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3799 start_nursery, end_nursery, PIN_TYPE_STACK);
3802 } END_FOREACH_THREAD
3806 ptr_on_stack (void *ptr)
3808 gpointer stack_start = &stack_start;
3809 SgenThreadInfo *info = mono_thread_info_current ();
3811 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3817 sgen_thread_register (SgenThreadInfo* info, void *addr)
3820 guint8 *staddr = NULL;
3822 #ifndef HAVE_KW_THREAD
3823 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3825 g_assert (!mono_native_tls_get_value (thread_info_key));
3826 mono_native_tls_set_value (thread_info_key, info);
3828 sgen_thread_info = info;
3831 #ifdef SGEN_POSIX_STW
3832 info->stop_count = -1;
3836 info->stack_start = NULL;
3837 info->stopped_ip = NULL;
3838 info->stopped_domain = NULL;
3840 memset (&info->ctx, 0, sizeof (MonoContext));
3842 memset (&info->regs, 0, sizeof (info->regs));
3845 sgen_init_tlab_info (info);
3847 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3849 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3850 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3853 info->stack_start_limit = staddr;
3855 info->stack_end = staddr + stsize;
3857 gsize stack_bottom = (gsize)addr;
3858 stack_bottom += 4095;
3859 stack_bottom &= ~4095;
3860 info->stack_end = (char*)stack_bottom;
3863 #ifdef HAVE_KW_THREAD
3864 stack_end = info->stack_end;
3867 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3869 if (gc_callbacks.thread_attach_func)
3870 info->runtime_data = gc_callbacks.thread_attach_func ();
3875 sgen_thread_detach (SgenThreadInfo *p)
3877 /* If a delegate is passed to native code and invoked on a thread we dont
3878 * know about, the jit will register it with mono_jit_thread_attach, but
3879 * we have no way of knowing when that thread goes away. SGen has a TSD
3880 * so we assume that if the domain is still registered, we can detach
3883 if (mono_domain_get ())
3884 mono_thread_detach_internal (mono_thread_internal_current ());
3888 sgen_thread_unregister (SgenThreadInfo *p)
3890 MonoNativeThreadId tid;
3892 tid = mono_thread_info_get_tid (p);
3893 binary_protocol_thread_unregister ((gpointer)tid);
3894 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3896 #ifndef HAVE_KW_THREAD
3897 mono_native_tls_set_value (thread_info_key, NULL);
3899 sgen_thread_info = NULL;
3902 if (p->info.runtime_thread)
3903 mono_threads_add_joinable_thread ((gpointer)tid);
3905 if (gc_callbacks.thread_detach_func) {
3906 gc_callbacks.thread_detach_func (p->runtime_data);
3907 p->runtime_data = NULL;
3913 sgen_thread_attach (SgenThreadInfo *info)
3916 /*this is odd, can we get attached before the gc is inited?*/
3920 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3921 info->runtime_data = gc_callbacks.thread_attach_func ();
3924 mono_gc_register_thread (void *baseptr)
3926 return mono_thread_info_attach (baseptr) != NULL;
3930 * mono_gc_set_stack_end:
3932 * Set the end of the current threads stack to STACK_END. The stack space between
3933 * STACK_END and the real end of the threads stack will not be scanned during collections.
3936 mono_gc_set_stack_end (void *stack_end)
3938 SgenThreadInfo *info;
3941 info = mono_thread_info_current ();
3943 g_assert (stack_end < info->stack_end);
3944 info->stack_end = stack_end;
3949 #if USE_PTHREAD_INTERCEPT
3953 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3955 return pthread_create (new_thread, attr, start_routine, arg);
3959 mono_gc_pthread_join (pthread_t thread, void **retval)
3961 return pthread_join (thread, retval);
3965 mono_gc_pthread_detach (pthread_t thread)
3967 return pthread_detach (thread);
3971 mono_gc_pthread_exit (void *retval)
3973 mono_thread_info_detach ();
3974 pthread_exit (retval);
3975 g_assert_not_reached ();
3978 #endif /* USE_PTHREAD_INTERCEPT */
3981 * ######################################################################
3982 * ######## Write barriers
3983 * ######################################################################
3987 * Note: the write barriers first do the needed GC work and then do the actual store:
3988 * this way the value is visible to the conservative GC scan after the write barrier
3989 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
3990 * the conservative scan, otherwise by the remembered set scan.
3993 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
3995 HEAVY_STAT (++stat_wbarrier_set_field);
3996 if (ptr_in_nursery (field_ptr)) {
3997 *(void**)field_ptr = value;
4000 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4002 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4004 remset.wbarrier_set_field (obj, field_ptr, value);
4008 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4010 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4011 if (ptr_in_nursery (slot_ptr)) {
4012 *(void**)slot_ptr = value;
4015 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4017 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4019 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4023 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4025 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4026 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4027 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4028 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4032 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4033 if (binary_protocol_is_heavy_enabled ()) {
4035 for (i = 0; i < count; ++i) {
4036 gpointer dest = (gpointer*)dest_ptr + i;
4037 gpointer obj = *((gpointer*)src_ptr + i);
4039 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4044 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4047 static char *found_obj;
4050 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4052 char *ptr = user_data;
4054 if (ptr >= obj && ptr < obj + size) {
4055 g_assert (!found_obj);
4060 /* for use in the debugger */
4061 char* find_object_for_ptr (char *ptr);
4063 find_object_for_ptr (char *ptr)
4065 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4067 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4068 find_object_for_ptr_callback, ptr, TRUE);
4074 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4079 * Very inefficient, but this is debugging code, supposed to
4080 * be called from gdb, so we don't care.
4083 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4088 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4092 HEAVY_STAT (++stat_wbarrier_generic_store);
4094 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4095 /* FIXME: ptr_in_heap must be called with the GC lock held */
4096 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4097 char *start = find_object_for_ptr (ptr);
4098 MonoObject *value = *(MonoObject**)ptr;
4102 MonoObject *obj = (MonoObject*)start;
4103 if (obj->vtable->domain != value->vtable->domain)
4104 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4110 obj = *(gpointer*)ptr;
4112 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4114 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4115 SGEN_LOG (8, "Skipping remset at %p", ptr);
4120 * We need to record old->old pointer locations for the
4121 * concurrent collector.
4123 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4124 SGEN_LOG (8, "Skipping remset at %p", ptr);
4128 SGEN_LOG (8, "Adding remset at %p", ptr);
4130 remset.wbarrier_generic_nostore (ptr);
4134 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4136 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4137 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4138 if (ptr_in_nursery (value))
4139 mono_gc_wbarrier_generic_nostore (ptr);
4140 sgen_dummy_use (value);
4143 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4144 * as an atomic operation with release semantics.
4147 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4149 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4151 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4153 InterlockedWritePointer (ptr, value);
4155 if (ptr_in_nursery (value))
4156 mono_gc_wbarrier_generic_nostore (ptr);
4158 sgen_dummy_use (value);
4161 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4163 mword *dest = _dest;
4168 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4170 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4173 size -= SIZEOF_VOID_P;
4178 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4180 #define HANDLE_PTR(ptr,obj) do { \
4181 gpointer o = *(gpointer*)(ptr); \
4183 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4184 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4189 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4191 #define SCAN_OBJECT_NOVTABLE
4192 #include "sgen-scan-object.h"
4197 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4199 HEAVY_STAT (++stat_wbarrier_value_copy);
4200 g_assert (klass->valuetype);
4202 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4204 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4205 size_t element_size = mono_class_value_size (klass, NULL);
4206 size_t size = count * element_size;
4207 mono_gc_memmove_atomic (dest, src, size);
4211 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4212 if (binary_protocol_is_heavy_enabled ()) {
4213 size_t element_size = mono_class_value_size (klass, NULL);
4215 for (i = 0; i < count; ++i) {
4216 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4217 (char*)src + i * element_size - sizeof (MonoObject),
4218 (mword) klass->gc_descr);
4223 remset.wbarrier_value_copy (dest, src, count, klass);
4227 * mono_gc_wbarrier_object_copy:
4229 * Write barrier to call when obj is the result of a clone or copy of an object.
4232 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4236 HEAVY_STAT (++stat_wbarrier_object_copy);
4238 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4239 size = mono_object_class (obj)->instance_size;
4240 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4241 size - sizeof (MonoObject));
4245 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4246 if (binary_protocol_is_heavy_enabled ())
4247 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4250 remset.wbarrier_object_copy (obj, src);
4255 * ######################################################################
4256 * ######## Other mono public interface functions.
4257 * ######################################################################
4260 #define REFS_SIZE 128
4263 MonoGCReferences callback;
4267 MonoObject *refs [REFS_SIZE];
4268 uintptr_t offsets [REFS_SIZE];
4272 #define HANDLE_PTR(ptr,obj) do { \
4274 if (hwi->count == REFS_SIZE) { \
4275 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4279 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4280 hwi->refs [hwi->count++] = *(ptr); \
4285 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4287 mword desc = sgen_obj_get_descriptor (start);
4289 #include "sgen-scan-object.h"
4293 walk_references (char *start, size_t size, void *data)
4295 HeapWalkInfo *hwi = data;
4298 collect_references (hwi, start, size);
4299 if (hwi->count || !hwi->called)
4300 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4304 * mono_gc_walk_heap:
4305 * @flags: flags for future use
4306 * @callback: a function pointer called for each object in the heap
4307 * @data: a user data pointer that is passed to callback
4309 * This function can be used to iterate over all the live objects in the heap:
4310 * for each object, @callback is invoked, providing info about the object's
4311 * location in memory, its class, its size and the objects it references.
4312 * For each referenced object it's offset from the object address is
4313 * reported in the offsets array.
4314 * The object references may be buffered, so the callback may be invoked
4315 * multiple times for the same object: in all but the first call, the size
4316 * argument will be zero.
4317 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4318 * profiler event handler.
4320 * Returns: a non-zero value if the GC doesn't support heap walking
4323 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4328 hwi.callback = callback;
4331 sgen_clear_nursery_fragments ();
4332 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4334 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4335 sgen_los_iterate_objects (walk_references, &hwi);
4341 mono_gc_collect (int generation)
4346 sgen_perform_collection (0, generation, "user request", TRUE);
4351 mono_gc_max_generation (void)
4357 mono_gc_collection_count (int generation)
4359 if (generation == 0)
4360 return gc_stats.minor_gc_count;
4361 return gc_stats.major_gc_count;
4365 mono_gc_get_used_size (void)
4369 tot = los_memory_usage;
4370 tot += nursery_section->next_data - nursery_section->data;
4371 tot += major_collector.get_used_size ();
4372 /* FIXME: account for pinned objects */
4378 mono_gc_get_los_limit (void)
4380 return MAX_SMALL_OBJ_SIZE;
4384 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4386 mono_unichar2 *new_end = str->chars + new_length;
4388 /* zero the discarded string. This null-delimits the string and allows
4389 * the space to be reclaimed by SGen. */
4391 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4392 CHECK_CANARY_FOR_OBJECT (str);
4393 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4394 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4396 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4399 str->length = new_length;
4403 mono_gc_user_markers_supported (void)
4409 mono_object_is_alive (MonoObject* o)
4415 mono_gc_get_generation (MonoObject *obj)
4417 if (ptr_in_nursery (obj))
4423 mono_gc_enable_events (void)
4428 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4430 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4434 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4436 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4440 mono_gc_weak_link_get (void **link_addr)
4442 void * volatile *link_addr_volatile;
4446 link_addr_volatile = link_addr;
4447 ptr = (void*)*link_addr_volatile;
4449 * At this point we have a hidden pointer. If the GC runs
4450 * here, it will not recognize the hidden pointer as a
4451 * reference, and if the object behind it is not referenced
4452 * elsewhere, it will be freed. Once the world is restarted
4453 * we reveal the pointer, giving us a pointer to a freed
4454 * object. To make sure we don't return it, we load the
4455 * hidden pointer again. If it's still the same, we can be
4456 * sure the object reference is valid.
4459 obj = (MonoObject*) REVEAL_POINTER (ptr);
4463 mono_memory_barrier ();
4466 * During the second bridge processing step the world is
4467 * running again. That step processes all weak links once
4468 * more to null those that refer to dead objects. Before that
4469 * is completed, those links must not be followed, so we
4470 * conservatively wait for bridge processing when any weak
4471 * link is dereferenced.
4473 if (G_UNLIKELY (bridge_processing_in_progress))
4474 mono_gc_wait_for_bridge_processing ();
4476 if ((void*)*link_addr_volatile != ptr)
4483 mono_gc_ephemeron_array_add (MonoObject *obj)
4485 EphemeronLinkNode *node;
4489 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4494 node->array = (char*)obj;
4495 node->next = ephemeron_list;
4496 ephemeron_list = node;
4498 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4505 mono_gc_set_allow_synchronous_major (gboolean flag)
4507 if (!major_collector.is_concurrent)
4510 allow_synchronous_major = flag;
4515 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4519 result = func (data);
4520 UNLOCK_INTERRUPTION;
4525 mono_gc_is_gc_thread (void)
4529 result = mono_thread_info_current () != NULL;
4535 is_critical_method (MonoMethod *method)
4537 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4541 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4545 va_start (ap, description_format);
4547 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4548 vfprintf (stderr, description_format, ap);
4550 fprintf (stderr, " - %s", fallback);
4551 fprintf (stderr, "\n");
4557 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4560 double val = strtod (opt, &endptr);
4561 if (endptr == opt) {
4562 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4565 else if (val < min || val > max) {
4566 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4574 mono_gc_base_init (void)
4576 MonoThreadInfoCallbacks cb;
4579 char *major_collector_opt = NULL;
4580 char *minor_collector_opt = NULL;
4581 size_t max_heap = 0;
4582 size_t soft_limit = 0;
4585 gboolean debug_print_allowance = FALSE;
4586 double allowance_ratio = 0, save_target = 0;
4587 gboolean have_split_nursery = FALSE;
4588 gboolean cement_enabled = TRUE;
4591 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4594 /* already inited */
4597 /* being inited by another thread */
4601 /* we will init it */
4604 g_assert_not_reached ();
4606 } while (result != 0);
4608 SGEN_TV_GETTIME (sgen_init_timestamp);
4610 LOCK_INIT (gc_mutex);
4612 pagesize = mono_pagesize ();
4613 gc_debug_file = stderr;
4615 cb.thread_register = sgen_thread_register;
4616 cb.thread_detach = sgen_thread_detach;
4617 cb.thread_unregister = sgen_thread_unregister;
4618 cb.thread_attach = sgen_thread_attach;
4619 cb.mono_method_is_critical = (gpointer)is_critical_method;
4621 cb.thread_exit = mono_gc_pthread_exit;
4622 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4625 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4627 LOCK_INIT (sgen_interruption_mutex);
4628 LOCK_INIT (pin_queue_mutex);
4630 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4631 opts = g_strsplit (env, ",", -1);
4632 for (ptr = opts; *ptr; ++ptr) {
4634 if (g_str_has_prefix (opt, "major=")) {
4635 opt = strchr (opt, '=') + 1;
4636 major_collector_opt = g_strdup (opt);
4637 } else if (g_str_has_prefix (opt, "minor=")) {
4638 opt = strchr (opt, '=') + 1;
4639 minor_collector_opt = g_strdup (opt);
4647 sgen_init_internal_allocator ();
4648 sgen_init_nursery_allocator ();
4649 sgen_init_fin_weak_hash ();
4651 sgen_init_hash_table ();
4652 sgen_init_descriptors ();
4653 sgen_init_gray_queues ();
4655 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4656 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4657 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4658 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4660 #ifndef HAVE_KW_THREAD
4661 mono_native_tls_alloc (&thread_info_key, NULL);
4662 #if defined(__APPLE__) || defined (HOST_WIN32)
4664 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4665 * where the two are the same.
4667 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4671 int tls_offset = -1;
4672 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4673 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4678 * This needs to happen before any internal allocations because
4679 * it inits the small id which is required for hazard pointer
4684 mono_thread_info_attach (&dummy);
4686 if (!minor_collector_opt) {
4687 sgen_simple_nursery_init (&sgen_minor_collector);
4689 if (!strcmp (minor_collector_opt, "simple")) {
4691 sgen_simple_nursery_init (&sgen_minor_collector);
4692 } else if (!strcmp (minor_collector_opt, "split")) {
4693 sgen_split_nursery_init (&sgen_minor_collector);
4694 have_split_nursery = TRUE;
4696 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4697 goto use_simple_nursery;
4701 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4702 use_marksweep_major:
4703 sgen_marksweep_init (&major_collector);
4704 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4705 sgen_marksweep_conc_init (&major_collector);
4707 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4708 goto use_marksweep_major;
4711 ///* Keep this the default for now */
4712 /* Precise marking is broken on all supported targets. Disable until fixed. */
4713 conservative_stack_mark = TRUE;
4715 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4718 gboolean usage_printed = FALSE;
4720 for (ptr = opts; *ptr; ++ptr) {
4722 if (!strcmp (opt, ""))
4724 if (g_str_has_prefix (opt, "major="))
4726 if (g_str_has_prefix (opt, "minor="))
4728 if (g_str_has_prefix (opt, "max-heap-size=")) {
4729 size_t max_heap_candidate = 0;
4730 opt = strchr (opt, '=') + 1;
4731 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4732 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4733 if (max_heap != max_heap_candidate)
4734 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4736 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4740 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4741 opt = strchr (opt, '=') + 1;
4742 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4743 if (soft_limit <= 0) {
4744 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4748 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4752 if (g_str_has_prefix (opt, "stack-mark=")) {
4753 opt = strchr (opt, '=') + 1;
4754 if (!strcmp (opt, "precise")) {
4755 conservative_stack_mark = FALSE;
4756 } else if (!strcmp (opt, "conservative")) {
4757 conservative_stack_mark = TRUE;
4759 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4760 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4764 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4765 opt = strchr (opt, '=') + 1;
4766 sgen_set_bridge_implementation (opt);
4769 if (g_str_has_prefix (opt, "toggleref-test")) {
4770 sgen_register_test_toggleref_callback ();
4775 if (g_str_has_prefix (opt, "nursery-size=")) {
4777 opt = strchr (opt, '=') + 1;
4778 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4779 #ifdef SGEN_ALIGN_NURSERY
4780 if ((val & (val - 1))) {
4781 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4785 if (val < SGEN_MAX_NURSERY_WASTE) {
4786 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4787 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4791 sgen_nursery_size = val;
4792 sgen_nursery_bits = 0;
4793 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4796 sgen_nursery_size = val;
4799 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4805 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4807 opt = strchr (opt, '=') + 1;
4808 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4809 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4814 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4816 opt = strchr (opt, '=') + 1;
4817 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4818 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4819 allowance_ratio = val;
4823 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4824 if (!major_collector.is_concurrent) {
4825 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4829 opt = strchr (opt, '=') + 1;
4831 if (!strcmp (opt, "yes")) {
4832 allow_synchronous_major = TRUE;
4833 } else if (!strcmp (opt, "no")) {
4834 allow_synchronous_major = FALSE;
4836 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4841 if (!strcmp (opt, "cementing")) {
4842 cement_enabled = TRUE;
4845 if (!strcmp (opt, "no-cementing")) {
4846 cement_enabled = FALSE;
4850 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4853 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4856 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4861 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4862 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4863 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4864 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4865 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4866 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4867 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4868 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4869 fprintf (stderr, " [no-]cementing\n");
4870 if (major_collector.is_concurrent)
4871 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4872 if (major_collector.print_gc_param_usage)
4873 major_collector.print_gc_param_usage ();
4874 if (sgen_minor_collector.print_gc_param_usage)
4875 sgen_minor_collector.print_gc_param_usage ();
4876 fprintf (stderr, " Experimental options:\n");
4877 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4878 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);
4879 fprintf (stderr, "\n");
4881 usage_printed = TRUE;
4886 if (major_collector.is_concurrent)
4887 sgen_workers_init (1);
4889 if (major_collector_opt)
4890 g_free (major_collector_opt);
4892 if (minor_collector_opt)
4893 g_free (minor_collector_opt);
4897 sgen_cement_init (cement_enabled);
4899 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4900 gboolean usage_printed = FALSE;
4902 opts = g_strsplit (env, ",", -1);
4903 for (ptr = opts; ptr && *ptr; ptr ++) {
4905 if (!strcmp (opt, ""))
4907 if (opt [0] >= '0' && opt [0] <= '9') {
4908 gc_debug_level = atoi (opt);
4913 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4914 gc_debug_file = fopen (rf, "wb");
4916 gc_debug_file = stderr;
4919 } else if (!strcmp (opt, "print-allowance")) {
4920 debug_print_allowance = TRUE;
4921 } else if (!strcmp (opt, "print-pinning")) {
4922 do_pin_stats = TRUE;
4923 } else if (!strcmp (opt, "verify-before-allocs")) {
4924 verify_before_allocs = 1;
4925 has_per_allocation_action = TRUE;
4926 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4927 char *arg = strchr (opt, '=') + 1;
4928 verify_before_allocs = atoi (arg);
4929 has_per_allocation_action = TRUE;
4930 } else if (!strcmp (opt, "collect-before-allocs")) {
4931 collect_before_allocs = 1;
4932 has_per_allocation_action = TRUE;
4933 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4934 char *arg = strchr (opt, '=') + 1;
4935 has_per_allocation_action = TRUE;
4936 collect_before_allocs = atoi (arg);
4937 } else if (!strcmp (opt, "verify-before-collections")) {
4938 whole_heap_check_before_collection = TRUE;
4939 } else if (!strcmp (opt, "check-at-minor-collections")) {
4940 consistency_check_at_minor_collection = TRUE;
4941 nursery_clear_policy = CLEAR_AT_GC;
4942 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4943 if (!major_collector.is_concurrent) {
4944 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4947 mod_union_consistency_check = TRUE;
4948 } else if (!strcmp (opt, "check-mark-bits")) {
4949 check_mark_bits_after_major_collection = TRUE;
4950 } else if (!strcmp (opt, "check-nursery-pinned")) {
4951 check_nursery_objects_pinned = TRUE;
4952 } else if (!strcmp (opt, "xdomain-checks")) {
4953 xdomain_checks = TRUE;
4954 } else if (!strcmp (opt, "clear-at-gc")) {
4955 nursery_clear_policy = CLEAR_AT_GC;
4956 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4957 nursery_clear_policy = CLEAR_AT_GC;
4958 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4959 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4960 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4961 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4962 } else if (!strcmp (opt, "check-scan-starts")) {
4963 do_scan_starts_check = TRUE;
4964 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4965 do_verify_nursery = TRUE;
4966 } else if (!strcmp (opt, "check-concurrent")) {
4967 if (!major_collector.is_concurrent) {
4968 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4971 do_concurrent_checks = TRUE;
4972 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4973 do_dump_nursery_content = TRUE;
4974 } else if (!strcmp (opt, "no-managed-allocator")) {
4975 sgen_set_use_managed_allocator (FALSE);
4976 } else if (!strcmp (opt, "disable-minor")) {
4977 disable_minor_collections = TRUE;
4978 } else if (!strcmp (opt, "disable-major")) {
4979 disable_major_collections = TRUE;
4980 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4981 char *filename = strchr (opt, '=') + 1;
4982 nursery_clear_policy = CLEAR_AT_GC;
4983 heap_dump_file = fopen (filename, "w");
4984 if (heap_dump_file) {
4985 fprintf (heap_dump_file, "<sgen-dump>\n");
4986 do_pin_stats = TRUE;
4988 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4989 char *filename = strchr (opt, '=') + 1;
4990 char *colon = strrchr (filename, ':');
4993 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
4994 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
4999 binary_protocol_init (filename, (long long)limit);
5000 } else if (!strcmp (opt, "nursery-canaries")) {
5001 do_verify_nursery = TRUE;
5002 sgen_set_use_managed_allocator (FALSE);
5003 enable_nursery_canaries = TRUE;
5004 } else if (!sgen_bridge_handle_gc_debug (opt)) {
5005 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5010 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);
5011 fprintf (stderr, "Valid <option>s are:\n");
5012 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5013 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5014 fprintf (stderr, " check-at-minor-collections\n");
5015 fprintf (stderr, " check-mark-bits\n");
5016 fprintf (stderr, " check-nursery-pinned\n");
5017 fprintf (stderr, " verify-before-collections\n");
5018 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5019 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5020 fprintf (stderr, " disable-minor\n");
5021 fprintf (stderr, " disable-major\n");
5022 fprintf (stderr, " xdomain-checks\n");
5023 fprintf (stderr, " check-concurrent\n");
5024 fprintf (stderr, " clear-[nursery-]at-gc\n");
5025 fprintf (stderr, " clear-at-tlab-creation\n");
5026 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5027 fprintf (stderr, " check-scan-starts\n");
5028 fprintf (stderr, " no-managed-allocator\n");
5029 fprintf (stderr, " print-allowance\n");
5030 fprintf (stderr, " print-pinning\n");
5031 fprintf (stderr, " heap-dump=<filename>\n");
5032 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5033 fprintf (stderr, " nursery-canaries\n");
5034 sgen_bridge_print_gc_debug_usage ();
5035 fprintf (stderr, "\n");
5037 usage_printed = TRUE;
5043 if (major_collector.post_param_init)
5044 major_collector.post_param_init (&major_collector);
5046 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5048 memset (&remset, 0, sizeof (remset));
5050 sgen_card_table_init (&remset);
5056 mono_gc_get_gc_name (void)
5061 static MonoMethod *write_barrier_method;
5064 sgen_is_critical_method (MonoMethod *method)
5066 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5070 sgen_has_critical_method (void)
5072 return write_barrier_method || sgen_has_managed_allocator ();
5078 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5080 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5081 #ifdef SGEN_ALIGN_NURSERY
5082 // if (ptr_in_nursery (ptr)) return;
5084 * Masking out the bits might be faster, but we would have to use 64 bit
5085 * immediates, which might be slower.
5087 mono_mb_emit_ldarg (mb, 0);
5088 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5089 mono_mb_emit_byte (mb, CEE_SHR_UN);
5090 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5091 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5093 if (!major_collector.is_concurrent) {
5094 // if (!ptr_in_nursery (*ptr)) return;
5095 mono_mb_emit_ldarg (mb, 0);
5096 mono_mb_emit_byte (mb, CEE_LDIND_I);
5097 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5098 mono_mb_emit_byte (mb, CEE_SHR_UN);
5099 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5100 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5103 int label_continue1, label_continue2;
5104 int dereferenced_var;
5106 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5107 mono_mb_emit_ldarg (mb, 0);
5108 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5109 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5111 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5112 mono_mb_emit_ldarg (mb, 0);
5113 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5114 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5117 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5120 mono_mb_patch_branch (mb, label_continue_1);
5121 mono_mb_patch_branch (mb, label_continue_2);
5123 // Dereference and store in local var
5124 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5125 mono_mb_emit_ldarg (mb, 0);
5126 mono_mb_emit_byte (mb, CEE_LDIND_I);
5127 mono_mb_emit_stloc (mb, dereferenced_var);
5129 if (!major_collector.is_concurrent) {
5130 // if (*ptr < sgen_get_nursery_start ()) return;
5131 mono_mb_emit_ldloc (mb, dereferenced_var);
5132 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5133 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5135 // if (*ptr >= sgen_get_nursery_end ()) return;
5136 mono_mb_emit_ldloc (mb, dereferenced_var);
5137 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5138 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5145 mono_gc_get_write_barrier (void)
5148 MonoMethodBuilder *mb;
5149 MonoMethodSignature *sig;
5150 #ifdef MANAGED_WBARRIER
5151 int i, nursery_check_labels [3];
5153 #ifdef HAVE_KW_THREAD
5154 int stack_end_offset = -1;
5156 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5157 g_assert (stack_end_offset != -1);
5161 // FIXME: Maybe create a separate version for ctors (the branch would be
5162 // correctly predicted more times)
5163 if (write_barrier_method)
5164 return write_barrier_method;
5166 /* Create the IL version of mono_gc_barrier_generic_store () */
5167 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5168 sig->ret = &mono_defaults.void_class->byval_arg;
5169 sig->params [0] = &mono_defaults.int_class->byval_arg;
5171 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5174 #ifdef MANAGED_WBARRIER
5175 emit_nursery_check (mb, nursery_check_labels);
5177 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5181 LDC_PTR sgen_cardtable
5183 address >> CARD_BITS
5187 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5188 LDC_PTR card_table_mask
5195 mono_mb_emit_ptr (mb, sgen_cardtable);
5196 mono_mb_emit_ldarg (mb, 0);
5197 mono_mb_emit_icon (mb, CARD_BITS);
5198 mono_mb_emit_byte (mb, CEE_SHR_UN);
5199 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5200 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5201 mono_mb_emit_byte (mb, CEE_AND);
5203 mono_mb_emit_byte (mb, CEE_ADD);
5204 mono_mb_emit_icon (mb, 1);
5205 mono_mb_emit_byte (mb, CEE_STIND_I1);
5208 for (i = 0; i < 3; ++i) {
5209 if (nursery_check_labels [i])
5210 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5212 mono_mb_emit_byte (mb, CEE_RET);
5214 mono_mb_emit_ldarg (mb, 0);
5215 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5216 mono_mb_emit_byte (mb, CEE_RET);
5219 res = mono_mb_create_method (mb, sig, 16);
5223 if (write_barrier_method) {
5224 /* Already created */
5225 mono_free_method (res);
5227 /* double-checked locking */
5228 mono_memory_barrier ();
5229 write_barrier_method = res;
5233 return write_barrier_method;
5237 mono_gc_get_description (void)
5239 return g_strdup ("sgen");
5243 mono_gc_set_desktop_mode (void)
5248 mono_gc_is_moving (void)
5254 mono_gc_is_disabled (void)
5260 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5267 sgen_get_nursery_clear_policy (void)
5269 return nursery_clear_policy;
5273 sgen_get_array_fill_vtable (void)
5275 if (!array_fill_vtable) {
5276 static MonoClass klass;
5277 static MonoVTable vtable;
5280 MonoDomain *domain = mono_get_root_domain ();
5283 klass.element_class = mono_defaults.byte_class;
5285 klass.instance_size = sizeof (MonoArray);
5286 klass.sizes.element_size = 1;
5287 klass.name = "array_filler_type";
5289 vtable.klass = &klass;
5291 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5294 array_fill_vtable = &vtable;
5296 return array_fill_vtable;
5306 sgen_gc_unlock (void)
5308 gboolean try_free = sgen_try_free_some_memory;
5309 sgen_try_free_some_memory = FALSE;
5310 mono_mutex_unlock (&gc_mutex);
5311 MONO_GC_UNLOCKED ();
5313 mono_thread_hazardous_try_free_some ();
5317 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5319 major_collector.iterate_live_block_ranges (callback);
5323 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5325 major_collector.scan_card_table (FALSE, queue);
5329 sgen_get_major_collector (void)
5331 return &major_collector;
5334 void mono_gc_set_skip_thread (gboolean skip)
5336 SgenThreadInfo *info = mono_thread_info_current ();
5339 info->gc_disabled = skip;
5344 sgen_get_remset (void)
5350 mono_gc_get_vtable_bits (MonoClass *class)
5353 /* FIXME move this to the bridge code */
5354 if (sgen_need_bridge_processing ()) {
5355 switch (sgen_bridge_class_kind (class)) {
5356 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5357 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5358 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5360 case GC_BRIDGE_OPAQUE_CLASS:
5361 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5365 if (fin_callbacks.is_class_finalization_aware) {
5366 if (fin_callbacks.is_class_finalization_aware (class))
5367 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5373 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5380 sgen_check_whole_heap_stw (void)
5382 sgen_stop_world (0);
5383 sgen_clear_nursery_fragments ();
5384 sgen_check_whole_heap (FALSE);
5385 sgen_restart_world (0, NULL);
5389 sgen_gc_event_moves (void)
5391 if (moved_objects_idx) {
5392 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5393 moved_objects_idx = 0;
5398 sgen_timestamp (void)
5400 SGEN_TV_DECLARE (timestamp);
5401 SGEN_TV_GETTIME (timestamp);
5402 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5406 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5408 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5409 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5411 fin_callbacks = *callbacks;
5418 #endif /* HAVE_SGEN_GC */