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;
606 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
609 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
614 g_assert (concurrent_collection_in_progress);
615 if (sgen_workers_have_started ()) {
616 sgen_workers_wake_up_all ();
618 if (concurrent_collection_in_progress)
619 g_assert (current_collection_generation == -1);
625 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
627 while (start < end) {
631 if (!*(void**)start) {
632 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
637 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
643 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
644 CHECK_CANARY_FOR_OBJECT (obj);
645 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
646 callback (obj, size, data);
647 CANARIFY_SIZE (size);
649 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
657 need_remove_object_for_domain (char *start, MonoDomain *domain)
659 if (mono_object_domain (start) == domain) {
660 SGEN_LOG (4, "Need to cleanup object %p", start);
661 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
668 process_object_for_domain_clearing (char *start, MonoDomain *domain)
670 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
671 if (vt->klass == mono_defaults.internal_thread_class)
672 g_assert (mono_object_domain (start) == mono_get_root_domain ());
673 /* The object could be a proxy for an object in the domain
675 #ifndef DISABLE_REMOTING
676 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
677 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
679 /* The server could already have been zeroed out, so
680 we need to check for that, too. */
681 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
682 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
683 ((MonoRealProxy*)start)->unwrapped_server = NULL;
690 clear_domain_process_object (char *obj, MonoDomain *domain)
694 process_object_for_domain_clearing (obj, domain);
695 remove = need_remove_object_for_domain (obj, domain);
697 if (remove && ((MonoObject*)obj)->synchronisation) {
698 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
700 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
707 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
709 if (clear_domain_process_object (obj, domain)) {
710 CANARIFY_SIZE (size);
711 memset (obj, 0, size);
716 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
718 clear_domain_process_object (obj, domain);
722 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
724 if (need_remove_object_for_domain (obj, domain))
725 major_collector.free_non_pinned_object (obj, size);
729 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
731 if (need_remove_object_for_domain (obj, domain))
732 major_collector.free_pinned_object (obj, size);
736 * When appdomains are unloaded we can easily remove objects that have finalizers,
737 * but all the others could still be present in random places on the heap.
738 * We need a sweep to get rid of them even though it's going to be costly
740 * The reason we need to remove them is because we access the vtable and class
741 * structures to know the object size and the reference bitmap: once the domain is
742 * unloaded the point to random memory.
745 mono_gc_clear_domain (MonoDomain * domain)
747 LOSObject *bigobj, *prev;
752 binary_protocol_domain_unload_begin (domain);
756 if (concurrent_collection_in_progress)
757 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
758 g_assert (!concurrent_collection_in_progress);
760 sgen_process_fin_stage_entries ();
761 sgen_process_dislink_stage_entries ();
763 sgen_clear_nursery_fragments ();
765 if (xdomain_checks && domain != mono_get_root_domain ()) {
766 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
767 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
768 sgen_check_for_xdomain_refs ();
771 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
772 to memory returned to the OS.*/
773 null_ephemerons_for_domain (domain);
775 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
776 sgen_null_links_for_domain (domain, i);
778 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
779 sgen_remove_finalizers_for_domain (domain, i);
781 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
782 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
784 /* We need two passes over major and large objects because
785 freeing such objects might give their memory back to the OS
786 (in the case of large objects) or obliterate its vtable
787 (pinned objects with major-copying or pinned and non-pinned
788 objects with major-mark&sweep), but we might need to
789 dereference a pointer from an object to another object if
790 the first object is a proxy. */
791 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
792 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
793 clear_domain_process_object (bigobj->data, domain);
796 for (bigobj = los_object_list; bigobj;) {
797 if (need_remove_object_for_domain (bigobj->data, domain)) {
798 LOSObject *to_free = bigobj;
800 prev->next = bigobj->next;
802 los_object_list = bigobj->next;
803 bigobj = bigobj->next;
804 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
805 sgen_los_free_object (to_free);
809 bigobj = bigobj->next;
811 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
812 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
814 if (domain == mono_get_root_domain ()) {
815 if (G_UNLIKELY (do_pin_stats))
816 sgen_pin_stats_print_class_stats ();
817 sgen_object_layout_dump (stdout);
820 sgen_restart_world (0, NULL);
822 binary_protocol_domain_unload_end (domain);
828 * sgen_add_to_global_remset:
830 * The global remset contains locations which point into newspace after
831 * a minor collection. This can happen if the objects they point to are pinned.
833 * LOCKING: If called from a parallel collector, the global remset
834 * lock must be held. For serial collectors that is not necessary.
837 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
839 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
841 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
843 if (!major_collector.is_concurrent) {
844 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
846 if (current_collection_generation == -1)
847 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
850 if (!object_is_pinned (obj))
851 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");
852 else if (sgen_cement_lookup_or_register (obj))
855 remset.record_pointer (ptr);
857 if (G_UNLIKELY (do_pin_stats))
858 sgen_pin_stats_register_global_remset (obj);
860 SGEN_LOG (8, "Adding global remset for %p", ptr);
861 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
865 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
866 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
867 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
868 vt->klass->name_space, vt->klass->name);
874 * sgen_drain_gray_stack:
876 * Scan objects in the gray stack until the stack is empty. This should be called
877 * frequently after each object is copied, to achieve better locality and cache
880 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
884 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
886 ScanObjectFunc scan_func = ctx.scan_func;
887 GrayQueue *queue = ctx.queue;
891 for (i = 0; i != max_objs; ++i) {
894 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
897 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
898 scan_func (obj, desc, queue);
900 } while (max_objs < 0);
905 * Addresses in the pin queue are already sorted. This function finds
906 * the object header for each address and pins the object. The
907 * addresses must be inside the nursery section. The (start of the)
908 * address array is overwritten with the addresses of the actually
909 * pinned objects. Return the number of pinned objects.
912 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
914 GCMemSection *section = nursery_section;
915 void **start = section->pin_queue_start;
916 void **end = start + section->pin_queue_num_entries;
917 void *start_nursery = section->data;
918 void *end_nursery = section->next_data;
923 void *pinning_front = start_nursery;
925 void **definitely_pinned = start;
926 ScanObjectFunc scan_func = ctx.scan_func;
927 SgenGrayQueue *queue = ctx.queue;
929 sgen_nursery_allocator_prepare_for_pinning ();
931 while (start < end) {
932 void *obj_to_pin = NULL;
933 size_t obj_to_pin_size = 0;
938 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
939 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
946 SGEN_LOG (5, "Considering pinning addr %p", addr);
947 /* We've already processed everything up to pinning_front. */
948 if (addr < pinning_front) {
954 * Find the closest scan start <= addr. We might search backward in the
955 * scan_starts array because entries might be NULL. In the worst case we
956 * start at start_nursery.
958 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
959 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
960 search_start = (void*)section->scan_starts [idx];
961 if (!search_start || search_start > addr) {
964 search_start = section->scan_starts [idx];
965 if (search_start && search_start <= addr)
968 if (!search_start || search_start > addr)
969 search_start = start_nursery;
973 * If the pinning front is closer than the scan start we found, start
974 * searching at the front.
976 if (search_start < pinning_front)
977 search_start = pinning_front;
980 * Now addr should be in an object a short distance from search_start.
982 * search_start must point to zeroed mem or point to an object.
988 if (!*(void**)search_start) {
989 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
990 /* The loop condition makes sure we don't overrun addr. */
994 obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
996 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
997 /* This is the object we're looking for. */
998 obj_to_pin = search_start;
999 obj_to_pin_size = obj_size;
1003 /* Skip to the next object */
1004 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
1005 CHECK_CANARY_FOR_OBJECT (search_start);
1006 CANARIFY_SIZE (obj_size);
1007 CANARIFY_SIZE (obj_to_pin_size);
1009 search_start = (void*)((char*)search_start + obj_size);
1010 } while (search_start <= addr);
1012 /* We've searched past the address we were looking for. */
1014 pinning_front = search_start;
1015 goto next_pin_queue_entry;
1019 * We've found an object to pin. It might still be a dummy array, but we
1020 * can advance the pinning front in any case.
1022 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1025 * If this is a dummy array marking the beginning of a nursery
1026 * fragment, we don't pin it.
1028 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1029 goto next_pin_queue_entry;
1032 * Finally - pin the object!
1034 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1036 scan_func (obj_to_pin, desc, queue);
1038 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1039 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1040 binary_protocol_pin (obj_to_pin,
1041 (gpointer)LOAD_VTABLE (obj_to_pin),
1042 safe_object_get_size (obj_to_pin));
1044 #ifdef ENABLE_DTRACE
1045 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1046 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1047 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1048 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1049 sgen_safe_object_get_size (obj_to_pin),
1050 vt->klass->name_space, vt->klass->name, gen);
1054 pin_object (obj_to_pin);
1055 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1056 if (G_UNLIKELY (do_pin_stats))
1057 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1058 definitely_pinned [count] = obj_to_pin;
1062 next_pin_queue_entry:
1066 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1067 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1068 GCRootReport report;
1070 for (idx = 0; idx < count; ++idx)
1071 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1072 notify_gc_roots (&report);
1074 stat_pinned_objects += count;
1079 pin_objects_in_nursery (ScanCopyContext ctx)
1083 if (!nursery_section->pin_queue_num_entries)
1086 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1087 nursery_section->pin_queue_num_entries = reduced_to;
1089 nursery_section->pin_queue_start = NULL;
1094 sgen_pin_object (void *object, GrayQueue *queue)
1096 g_assert (!concurrent_collection_in_progress);
1098 SGEN_PIN_OBJECT (object);
1099 sgen_pin_stage_ptr (object);
1101 if (G_UNLIKELY (do_pin_stats))
1102 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1104 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor (object));
1105 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1107 #ifdef ENABLE_DTRACE
1108 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1109 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1110 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1111 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1117 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1121 gboolean major_pinned = FALSE;
1123 if (sgen_ptr_in_nursery (obj)) {
1124 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1125 sgen_pin_object (obj, queue);
1129 major_collector.pin_major_object (obj, queue);
1130 major_pinned = TRUE;
1133 vtable_word = *(mword*)obj;
1134 /*someone else forwarded it, update the pointer and bail out*/
1135 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1136 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1140 /*someone pinned it, nothing to do.*/
1141 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1146 /* Sort the addresses in array in increasing order.
1147 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1150 sgen_sort_addresses (void **array, size_t size)
1155 for (i = 1; i < size; ++i) {
1158 size_t parent = (child - 1) / 2;
1160 if (array [parent] >= array [child])
1163 tmp = array [parent];
1164 array [parent] = array [child];
1165 array [child] = tmp;
1171 for (i = size - 1; i > 0; --i) {
1174 array [i] = array [0];
1180 while (root * 2 + 1 <= end) {
1181 size_t child = root * 2 + 1;
1183 if (child < end && array [child] < array [child + 1])
1185 if (array [root] >= array [child])
1189 array [root] = array [child];
1190 array [child] = tmp;
1198 * Scan the memory between start and end and queue values which could be pointers
1199 * to the area between start_nursery and end_nursery for later consideration.
1200 * Typically used for thread stacks.
1203 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1207 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1208 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1211 while (start < end) {
1212 if (*start >= start_nursery && *start < end_nursery) {
1214 * *start can point to the middle of an object
1215 * note: should we handle pointing at the end of an object?
1216 * pinning in C# code disallows pointing at the end of an object
1217 * but there is some small chance that an optimizing C compiler
1218 * may keep the only reference to an object by pointing
1219 * at the end of it. We ignore this small chance for now.
1220 * Pointers to the end of an object are indistinguishable
1221 * from pointers to the start of the next object in memory
1222 * so if we allow that we'd need to pin two objects...
1223 * We queue the pointer in an array, the
1224 * array will then be sorted and uniqued. This way
1225 * we can coalesce several pinning pointers and it should
1226 * be faster since we'd do a memory scan with increasing
1227 * addresses. Note: we can align the address to the allocation
1228 * alignment, so the unique process is more effective.
1230 mword addr = (mword)*start;
1231 addr &= ~(ALLOC_ALIGN - 1);
1232 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1233 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1234 sgen_pin_stage_ptr ((void*)addr);
1237 if (G_UNLIKELY (do_pin_stats)) {
1238 if (ptr_in_nursery ((void*)addr))
1239 sgen_pin_stats_register_address ((char*)addr, pin_type);
1245 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1249 * The first thing we do in a collection is to identify pinned objects.
1250 * This function considers all the areas of memory that need to be
1251 * conservatively scanned.
1254 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1258 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);
1259 /* objects pinned from the API are inside these roots */
1260 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1261 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1262 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1263 } SGEN_HASH_TABLE_FOREACH_END;
1264 /* now deal with the thread stacks
1265 * in the future we should be able to conservatively scan only:
1266 * *) the cpu registers
1267 * *) the unmanaged stack frames
1268 * *) the _last_ managed stack frame
1269 * *) pointers slots in managed frames
1271 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1275 unpin_objects_from_queue (SgenGrayQueue *queue)
1280 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1283 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1284 SGEN_UNPIN_OBJECT (addr);
1289 CopyOrMarkObjectFunc func;
1291 } UserCopyOrMarkData;
1294 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1296 UserCopyOrMarkData *data = gc_data;
1298 data->func (obj, data->queue);
1302 * The memory area from start_root to end_root contains pointers to objects.
1303 * Their position is precisely described by @desc (this means that the pointer
1304 * can be either NULL or the pointer to the start of an object).
1305 * This functions copies them to to_space updates them.
1307 * This function is not thread-safe!
1310 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1312 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1313 SgenGrayQueue *queue = ctx.queue;
1315 switch (desc & ROOT_DESC_TYPE_MASK) {
1316 case ROOT_DESC_BITMAP:
1317 desc >>= ROOT_DESC_TYPE_SHIFT;
1319 if ((desc & 1) && *start_root) {
1320 copy_func (start_root, queue);
1321 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1322 sgen_drain_gray_stack (-1, ctx);
1328 case ROOT_DESC_COMPLEX: {
1329 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1330 gsize bwords = (*bitmap_data) - 1;
1331 void **start_run = start_root;
1333 while (bwords-- > 0) {
1334 gsize bmap = *bitmap_data++;
1335 void **objptr = start_run;
1337 if ((bmap & 1) && *objptr) {
1338 copy_func (objptr, queue);
1339 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1340 sgen_drain_gray_stack (-1, ctx);
1345 start_run += GC_BITS_PER_WORD;
1349 case ROOT_DESC_USER: {
1350 UserCopyOrMarkData data = { copy_func, queue };
1351 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1352 marker (start_root, single_arg_user_copy_or_mark, &data);
1355 case ROOT_DESC_RUN_LEN:
1356 g_assert_not_reached ();
1358 g_assert_not_reached ();
1363 reset_heap_boundaries (void)
1365 lowest_heap_address = ~(mword)0;
1366 highest_heap_address = 0;
1370 sgen_update_heap_boundaries (mword low, mword high)
1375 old = lowest_heap_address;
1378 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1381 old = highest_heap_address;
1384 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1388 * Allocate and setup the data structures needed to be able to allocate objects
1389 * in the nursery. The nursery is stored in nursery_section.
1392 alloc_nursery (void)
1394 GCMemSection *section;
1399 if (nursery_section)
1401 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1402 /* later we will alloc a larger area for the nursery but only activate
1403 * what we need. The rest will be used as expansion if we have too many pinned
1404 * objects in the existing nursery.
1406 /* FIXME: handle OOM */
1407 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1409 alloc_size = sgen_nursery_size;
1411 /* If there isn't enough space even for the nursery we should simply abort. */
1412 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1414 #ifdef SGEN_ALIGN_NURSERY
1415 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1417 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1419 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1420 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 ());
1421 section->data = section->next_data = data;
1422 section->size = alloc_size;
1423 section->end_data = data + sgen_nursery_size;
1424 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1425 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1426 section->num_scan_start = scan_starts;
1428 nursery_section = section;
1430 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1434 mono_gc_get_nursery (int *shift_bits, size_t *size)
1436 *size = sgen_nursery_size;
1437 #ifdef SGEN_ALIGN_NURSERY
1438 *shift_bits = DEFAULT_NURSERY_BITS;
1442 return sgen_get_nursery_start ();
1446 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1448 SgenThreadInfo *info = mono_thread_info_current ();
1450 /* Could be called from sgen_thread_unregister () with a NULL info */
1453 info->stopped_domain = domain;
1458 mono_gc_precise_stack_mark_enabled (void)
1460 return !conservative_stack_mark;
1464 mono_gc_get_logfile (void)
1466 return gc_debug_file;
1470 report_finalizer_roots_list (FinalizeReadyEntry *list)
1472 GCRootReport report;
1473 FinalizeReadyEntry *fin;
1476 for (fin = list; fin; fin = fin->next) {
1479 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1481 notify_gc_roots (&report);
1485 report_finalizer_roots (void)
1487 report_finalizer_roots_list (fin_ready_list);
1488 report_finalizer_roots_list (critical_fin_list);
1491 static GCRootReport *root_report;
1494 single_arg_report_root (void **obj, void *gc_data)
1497 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1501 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1503 switch (desc & ROOT_DESC_TYPE_MASK) {
1504 case ROOT_DESC_BITMAP:
1505 desc >>= ROOT_DESC_TYPE_SHIFT;
1507 if ((desc & 1) && *start_root) {
1508 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1514 case ROOT_DESC_COMPLEX: {
1515 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1516 gsize bwords = (*bitmap_data) - 1;
1517 void **start_run = start_root;
1519 while (bwords-- > 0) {
1520 gsize bmap = *bitmap_data++;
1521 void **objptr = start_run;
1523 if ((bmap & 1) && *objptr) {
1524 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1529 start_run += GC_BITS_PER_WORD;
1533 case ROOT_DESC_USER: {
1534 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1535 root_report = report;
1536 marker (start_root, single_arg_report_root, NULL);
1539 case ROOT_DESC_RUN_LEN:
1540 g_assert_not_reached ();
1542 g_assert_not_reached ();
1547 report_registered_roots_by_type (int root_type)
1549 GCRootReport report;
1553 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1554 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1555 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1556 } SGEN_HASH_TABLE_FOREACH_END;
1557 notify_gc_roots (&report);
1561 report_registered_roots (void)
1563 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1564 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1568 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1570 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1571 SgenGrayQueue *queue = ctx.queue;
1572 FinalizeReadyEntry *fin;
1574 for (fin = list; fin; fin = fin->next) {
1577 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1578 copy_func (&fin->object, queue);
1583 generation_name (int generation)
1585 switch (generation) {
1586 case GENERATION_NURSERY: return "nursery";
1587 case GENERATION_OLD: return "old";
1588 default: g_assert_not_reached ();
1593 sgen_generation_name (int generation)
1595 return generation_name (generation);
1598 SgenObjectOperations *
1599 sgen_get_current_object_ops (void){
1600 return ¤t_object_ops;
1605 finish_gray_stack (int generation, GrayQueue *queue)
1609 int done_with_ephemerons, ephemeron_rounds = 0;
1610 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1611 ScanObjectFunc scan_func = current_object_ops.scan_object;
1612 ScanCopyContext ctx = { scan_func, copy_func, queue };
1613 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1614 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1617 * We copied all the reachable objects. Now it's the time to copy
1618 * the objects that were not referenced by the roots, but by the copied objects.
1619 * we built a stack of objects pointed to by gray_start: they are
1620 * additional roots and we may add more items as we go.
1621 * We loop until gray_start == gray_objects which means no more objects have
1622 * been added. Note this is iterative: no recursion is involved.
1623 * We need to walk the LO list as well in search of marked big objects
1624 * (use a flag since this is needed only on major collections). We need to loop
1625 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1626 * To achieve better cache locality and cache usage, we drain the gray stack
1627 * frequently, after each object is copied, and just finish the work here.
1629 sgen_drain_gray_stack (-1, ctx);
1631 SGEN_LOG (2, "%s generation done", generation_name (generation));
1634 Reset bridge data, we might have lingering data from a previous collection if this is a major
1635 collection trigged by minor overflow.
1637 We must reset the gathered bridges since their original block might be evacuated due to major
1638 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1640 if (sgen_need_bridge_processing ())
1641 sgen_bridge_reset_data ();
1644 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1645 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1646 * objects that are in fact reachable.
1648 done_with_ephemerons = 0;
1650 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1651 sgen_drain_gray_stack (-1, ctx);
1653 } while (!done_with_ephemerons);
1655 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1657 if (sgen_need_bridge_processing ()) {
1658 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1659 sgen_drain_gray_stack (-1, ctx);
1660 sgen_collect_bridge_objects (generation, ctx);
1661 if (generation == GENERATION_OLD)
1662 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1665 Do the first bridge step here, as the collector liveness state will become useless after that.
1667 An important optimization is to only proccess the possibly dead part of the object graph and skip
1668 over all live objects as we transitively know everything they point must be alive too.
1670 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1672 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1673 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1676 sgen_bridge_processing_stw_step ();
1680 Make sure we drain the gray stack before processing disappearing links and finalizers.
1681 If we don't make sure it is empty we might wrongly see a live object as dead.
1683 sgen_drain_gray_stack (-1, ctx);
1686 We must clear weak links that don't track resurrection before processing object ready for
1687 finalization so they can be cleared before that.
1689 sgen_null_link_in_range (generation, TRUE, ctx);
1690 if (generation == GENERATION_OLD)
1691 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1694 /* walk the finalization queue and move also the objects that need to be
1695 * finalized: use the finalized objects as new roots so the objects they depend
1696 * on are also not reclaimed. As with the roots above, only objects in the nursery
1697 * are marked/copied.
1699 sgen_finalize_in_range (generation, ctx);
1700 if (generation == GENERATION_OLD)
1701 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1702 /* drain the new stack that might have been created */
1703 SGEN_LOG (6, "Precise scan of gray area post fin");
1704 sgen_drain_gray_stack (-1, ctx);
1707 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1709 done_with_ephemerons = 0;
1711 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1712 sgen_drain_gray_stack (-1, ctx);
1714 } while (!done_with_ephemerons);
1717 * Clear ephemeron pairs with unreachable keys.
1718 * We pass the copy func so we can figure out if an array was promoted or not.
1720 clear_unreachable_ephemerons (ctx);
1723 * We clear togglerefs only after all possible chances of revival are done.
1724 * This is semantically more inline with what users expect and it allows for
1725 * user finalizers to correctly interact with TR objects.
1727 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1730 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1733 * handle disappearing links
1734 * Note we do this after checking the finalization queue because if an object
1735 * survives (at least long enough to be finalized) we don't clear the link.
1736 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1737 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1740 g_assert (sgen_gray_object_queue_is_empty (queue));
1742 sgen_null_link_in_range (generation, FALSE, ctx);
1743 if (generation == GENERATION_OLD)
1744 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1745 if (sgen_gray_object_queue_is_empty (queue))
1747 sgen_drain_gray_stack (-1, ctx);
1750 g_assert (sgen_gray_object_queue_is_empty (queue));
1752 sgen_gray_object_queue_trim_free_list (queue);
1756 sgen_check_section_scan_starts (GCMemSection *section)
1759 for (i = 0; i < section->num_scan_start; ++i) {
1760 if (section->scan_starts [i]) {
1761 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1762 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1768 check_scan_starts (void)
1770 if (!do_scan_starts_check)
1772 sgen_check_section_scan_starts (nursery_section);
1773 major_collector.check_scan_starts ();
1777 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1781 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1782 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1783 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1784 } SGEN_HASH_TABLE_FOREACH_END;
1788 sgen_dump_occupied (char *start, char *end, char *section_start)
1790 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1794 sgen_dump_section (GCMemSection *section, const char *type)
1796 char *start = section->data;
1797 char *end = section->data + section->size;
1798 char *occ_start = NULL;
1800 char *old_start = NULL; /* just for debugging */
1802 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1804 while (start < end) {
1808 if (!*(void**)start) {
1810 sgen_dump_occupied (occ_start, start, section->data);
1813 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1816 g_assert (start < section->next_data);
1821 vt = (GCVTable*)LOAD_VTABLE (start);
1824 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1827 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1828 start - section->data,
1829 vt->klass->name_space, vt->klass->name,
1837 sgen_dump_occupied (occ_start, start, section->data);
1839 fprintf (heap_dump_file, "</section>\n");
1843 dump_object (MonoObject *obj, gboolean dump_location)
1845 static char class_name [1024];
1847 MonoClass *class = mono_object_class (obj);
1851 * Python's XML parser is too stupid to parse angle brackets
1852 * in strings, so we just ignore them;
1855 while (class->name [i] && j < sizeof (class_name) - 1) {
1856 if (!strchr ("<>\"", class->name [i]))
1857 class_name [j++] = class->name [i];
1860 g_assert (j < sizeof (class_name));
1863 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1864 class->name_space, class_name,
1865 safe_object_get_size (obj));
1866 if (dump_location) {
1867 const char *location;
1868 if (ptr_in_nursery (obj))
1869 location = "nursery";
1870 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1874 fprintf (heap_dump_file, " location=\"%s\"", location);
1876 fprintf (heap_dump_file, "/>\n");
1880 dump_heap (const char *type, int num, const char *reason)
1885 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1887 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1888 fprintf (heap_dump_file, ">\n");
1889 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1890 sgen_dump_internal_mem_usage (heap_dump_file);
1891 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1892 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1893 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1895 fprintf (heap_dump_file, "<pinned-objects>\n");
1896 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1897 dump_object (list->obj, TRUE);
1898 fprintf (heap_dump_file, "</pinned-objects>\n");
1900 sgen_dump_section (nursery_section, "nursery");
1902 major_collector.dump_heap (heap_dump_file);
1904 fprintf (heap_dump_file, "<los>\n");
1905 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1906 dump_object ((MonoObject*)bigobj->data, FALSE);
1907 fprintf (heap_dump_file, "</los>\n");
1909 fprintf (heap_dump_file, "</collection>\n");
1913 sgen_register_moved_object (void *obj, void *destination)
1915 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1917 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1918 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1919 moved_objects_idx = 0;
1921 moved_objects [moved_objects_idx++] = obj;
1922 moved_objects [moved_objects_idx++] = destination;
1928 static gboolean inited = FALSE;
1933 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1935 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1936 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pinning);
1937 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1938 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1939 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1940 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1941 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1942 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1944 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1945 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pinning);
1946 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1947 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1948 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1949 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1950 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1951 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1952 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1953 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1954 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1955 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_sweep);
1956 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1958 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
1960 #ifdef HEAVY_STATISTICS
1961 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1962 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1963 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1964 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1965 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1966 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1967 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1968 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1969 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1971 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
1972 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
1974 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
1975 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
1976 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
1977 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
1979 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
1980 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
1982 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
1984 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
1985 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
1986 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
1987 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
1989 sgen_nursery_allocator_init_heavy_stats ();
1990 sgen_alloc_init_heavy_stats ();
1998 reset_pinned_from_failed_allocation (void)
2000 bytes_pinned_from_failed_allocation = 0;
2004 sgen_set_pinned_from_failed_allocation (mword objsize)
2006 bytes_pinned_from_failed_allocation += objsize;
2010 sgen_collection_is_concurrent (void)
2012 switch (current_collection_generation) {
2013 case GENERATION_NURSERY:
2015 case GENERATION_OLD:
2016 return concurrent_collection_in_progress;
2018 g_error ("Invalid current generation %d", current_collection_generation);
2023 sgen_concurrent_collection_in_progress (void)
2025 return concurrent_collection_in_progress;
2032 } FinishRememberedSetScanJobData;
2035 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2037 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2039 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2040 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2045 CopyOrMarkObjectFunc copy_or_mark_func;
2046 ScanObjectFunc scan_func;
2050 } ScanFromRegisteredRootsJobData;
2053 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2055 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2056 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2057 sgen_workers_get_job_gray_queue (worker_data) };
2059 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2060 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2067 } ScanThreadDataJobData;
2070 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2072 ScanThreadDataJobData *job_data = job_data_untyped;
2074 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2075 sgen_workers_get_job_gray_queue (worker_data));
2076 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2080 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2082 FinalizeReadyEntry *list = job_data_untyped;
2083 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2085 scan_finalizer_entries (list, ctx);
2089 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2091 g_assert (concurrent_collection_in_progress);
2092 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2096 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2098 g_assert (concurrent_collection_in_progress);
2099 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2103 verify_scan_starts (char *start, char *end)
2107 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2108 char *addr = nursery_section->scan_starts [i];
2109 if (addr > start && addr < end)
2110 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2115 verify_nursery (void)
2117 char *start, *end, *cur, *hole_start;
2119 if (!do_verify_nursery)
2122 if (nursery_canaries_enabled ())
2123 SGEN_LOG (1, "Checking nursery canaries...");
2125 /*This cleans up unused fragments */
2126 sgen_nursery_allocator_prepare_for_pinning ();
2128 hole_start = start = cur = sgen_get_nursery_start ();
2129 end = sgen_get_nursery_end ();
2134 if (!*(void**)cur) {
2135 cur += sizeof (void*);
2139 if (object_is_forwarded (cur))
2140 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2141 else if (object_is_pinned (cur))
2142 SGEN_LOG (1, "PINNED OBJ %p", cur);
2144 ss = safe_object_get_size ((MonoObject*)cur);
2145 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2146 verify_scan_starts (cur, cur + size);
2147 if (do_dump_nursery_content) {
2148 if (cur > hole_start)
2149 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2150 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 ());
2152 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2153 CHECK_CANARY_FOR_OBJECT (cur);
2154 CANARIFY_SIZE (size);
2162 * Checks that no objects in the nursery are fowarded or pinned. This
2163 * is a precondition to restarting the mutator while doing a
2164 * concurrent collection. Note that we don't clear fragments because
2165 * we depend on that having happened earlier.
2168 check_nursery_is_clean (void)
2170 char *start, *end, *cur;
2172 start = cur = sgen_get_nursery_start ();
2173 end = sgen_get_nursery_end ();
2178 if (!*(void**)cur) {
2179 cur += sizeof (void*);
2183 g_assert (!object_is_forwarded (cur));
2184 g_assert (!object_is_pinned (cur));
2186 ss = safe_object_get_size ((MonoObject*)cur);
2187 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2188 verify_scan_starts (cur, cur + size);
2195 init_gray_queue (void)
2197 if (sgen_collection_is_concurrent ()) {
2198 sgen_workers_init_distribute_gray_queue ();
2199 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2200 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2202 sgen_gray_object_queue_init (&gray_queue, NULL);
2207 * Collect objects in the nursery. Returns whether to trigger a major
2211 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2213 gboolean needs_major;
2214 size_t max_garbage_amount;
2216 FinishRememberedSetScanJobData *frssjd;
2217 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2218 ScanThreadDataJobData *stdjd;
2219 mword fragment_total;
2220 ScanCopyContext ctx;
2224 if (disable_minor_collections)
2227 TV_GETTIME (last_minor_collection_start_tv);
2228 atv = last_minor_collection_start_tv;
2230 MONO_GC_BEGIN (GENERATION_NURSERY);
2231 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2235 #ifndef DISABLE_PERFCOUNTERS
2236 mono_perfcounters->gc_collections0++;
2239 current_collection_generation = GENERATION_NURSERY;
2240 current_object_ops = sgen_minor_collector.serial_ops;
2242 reset_pinned_from_failed_allocation ();
2244 check_scan_starts ();
2246 sgen_nursery_alloc_prepare_for_minor ();
2250 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2251 /* FIXME: optimize later to use the higher address where an object can be present */
2252 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2254 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 ()));
2255 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2256 g_assert (nursery_section->size >= max_garbage_amount);
2258 /* world must be stopped already */
2260 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2262 if (xdomain_checks) {
2263 sgen_clear_nursery_fragments ();
2264 sgen_check_for_xdomain_refs ();
2267 nursery_section->next_data = nursery_next;
2269 major_collector.start_nursery_collection ();
2271 sgen_memgov_minor_collection_start ();
2275 gc_stats.minor_gc_count ++;
2277 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2279 sgen_process_fin_stage_entries ();
2280 sgen_process_dislink_stage_entries ();
2282 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2284 /* pin from pinned handles */
2285 sgen_init_pinning ();
2286 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2287 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2288 /* pin cemented objects */
2289 sgen_pin_cemented_objects ();
2290 /* identify pinned objects */
2291 sgen_optimize_pin_queue ();
2292 sgen_pinning_setup_section (nursery_section);
2293 ctx.scan_func = NULL;
2294 ctx.copy_func = NULL;
2295 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2296 pin_objects_in_nursery (ctx);
2297 sgen_pinning_trim_queue_to_section (nursery_section);
2300 time_minor_pinning += TV_ELAPSED (btv, atv);
2301 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2302 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2304 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2306 if (whole_heap_check_before_collection) {
2307 sgen_clear_nursery_fragments ();
2308 sgen_check_whole_heap (finish_up_concurrent_mark);
2310 if (consistency_check_at_minor_collection)
2311 sgen_check_consistency ();
2313 sgen_workers_start_all_workers ();
2314 sgen_workers_start_marking ();
2316 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2317 frssjd->heap_start = sgen_get_nursery_start ();
2318 frssjd->heap_end = nursery_next;
2319 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2321 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2323 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2324 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2326 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2328 /* FIXME: why is this here? */
2329 ctx.scan_func = current_object_ops.scan_object;
2330 ctx.copy_func = NULL;
2331 ctx.queue = &gray_queue;
2332 sgen_drain_gray_stack (-1, ctx);
2334 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2335 report_registered_roots ();
2336 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2337 report_finalizer_roots ();
2339 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2341 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2343 /* registered roots, this includes static fields */
2344 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2345 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2346 scrrjd_normal->scan_func = current_object_ops.scan_object;
2347 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2348 scrrjd_normal->heap_end = nursery_next;
2349 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2350 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2352 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2353 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2354 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2355 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2356 scrrjd_wbarrier->heap_end = nursery_next;
2357 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2358 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2361 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2363 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2366 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2367 stdjd->heap_start = sgen_get_nursery_start ();
2368 stdjd->heap_end = nursery_next;
2369 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2372 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2375 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2377 g_assert (!sgen_collection_is_concurrent ());
2379 /* Scan the list of objects ready for finalization. If */
2380 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2381 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2383 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2385 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2387 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2388 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2390 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2393 * The (single-threaded) finalization code might have done
2394 * some copying/marking so we can only reset the GC thread's
2395 * worker data here instead of earlier when we joined the
2398 sgen_workers_reset_data ();
2400 if (objects_pinned) {
2401 sgen_optimize_pin_queue ();
2402 sgen_pinning_setup_section (nursery_section);
2405 /* walk the pin_queue, build up the fragment list of free memory, unmark
2406 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2409 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2410 fragment_total = sgen_build_nursery_fragments (nursery_section,
2411 nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2413 if (!fragment_total)
2416 /* Clear TLABs for all threads */
2417 sgen_clear_tlabs ();
2419 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2421 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2422 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2424 if (consistency_check_at_minor_collection)
2425 sgen_check_major_refs ();
2427 major_collector.finish_nursery_collection ();
2429 TV_GETTIME (last_minor_collection_end_tv);
2430 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2433 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2435 /* prepare the pin queue for the next collection */
2436 sgen_finish_pinning ();
2437 if (fin_ready_list || critical_fin_list) {
2438 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2439 mono_gc_finalize_notify ();
2441 sgen_pin_stats_reset ();
2442 /* clear cemented hash */
2443 sgen_cement_clear_below_threshold ();
2445 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2447 remset.finish_minor_collection ();
2449 check_scan_starts ();
2451 binary_protocol_flush_buffers (FALSE);
2453 sgen_memgov_minor_collection_end ();
2455 /*objects are late pinned because of lack of memory, so a major is a good call*/
2456 needs_major = objects_pinned > 0;
2457 current_collection_generation = -1;
2460 MONO_GC_END (GENERATION_NURSERY);
2461 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY);
2463 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2464 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2470 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2473 * This is called on all objects in the nursery, including pinned ones, so we need
2474 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2476 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2480 scan_nursery_objects (ScanCopyContext ctx)
2482 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2483 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2487 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2492 /* FIXME: only use these values for the precise scan
2493 * note that to_space pointers should be excluded anyway...
2495 char *heap_start = NULL;
2496 char *heap_end = (char*)-1;
2497 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2498 GCRootReport root_report = { 0 };
2499 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2500 ScanThreadDataJobData *stdjd;
2501 ScanCopyContext ctx;
2503 if (concurrent_collection_in_progress) {
2504 /*This cleans up unused fragments */
2505 sgen_nursery_allocator_prepare_for_pinning ();
2507 if (do_concurrent_checks)
2508 check_nursery_is_clean ();
2510 /* The concurrent collector doesn't touch the nursery. */
2511 sgen_nursery_alloc_prepare_for_major ();
2518 /* Pinning depends on this */
2519 sgen_clear_nursery_fragments ();
2521 if (whole_heap_check_before_collection)
2522 sgen_check_whole_heap (finish_up_concurrent_mark);
2525 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2527 if (!sgen_collection_is_concurrent ())
2528 nursery_section->next_data = sgen_get_nursery_end ();
2529 /* we should also coalesce scanning from sections close to each other
2530 * and deal with pointers outside of the sections later.
2534 *major_collector.have_swept = FALSE;
2536 if (xdomain_checks) {
2537 sgen_clear_nursery_fragments ();
2538 sgen_check_for_xdomain_refs ();
2541 if (!concurrent_collection_in_progress) {
2542 /* Remsets are not useful for a major collection */
2543 remset.prepare_for_major_collection ();
2546 sgen_process_fin_stage_entries ();
2547 sgen_process_dislink_stage_entries ();
2550 sgen_init_pinning ();
2551 SGEN_LOG (6, "Collecting pinned addresses");
2552 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2554 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2555 if (major_collector.is_concurrent) {
2557 * The concurrent major collector cannot evict
2558 * yet, so we need to pin cemented objects to
2559 * not break some asserts.
2561 * FIXME: We could evict now!
2563 sgen_pin_cemented_objects ();
2566 if (!concurrent_collection_in_progress)
2567 sgen_cement_reset ();
2570 sgen_optimize_pin_queue ();
2573 * The concurrent collector doesn't move objects, neither on
2574 * the major heap nor in the nursery, so we can mark even
2575 * before pinning has finished. For the non-concurrent
2576 * collector we start the workers after pinning.
2578 if (concurrent_collection_in_progress) {
2579 sgen_workers_start_all_workers ();
2580 sgen_workers_start_marking ();
2584 * pin_queue now contains all candidate pointers, sorted and
2585 * uniqued. We must do two passes now to figure out which
2586 * objects are pinned.
2588 * The first is to find within the pin_queue the area for each
2589 * section. This requires that the pin_queue be sorted. We
2590 * also process the LOS objects and pinned chunks here.
2592 * The second, destructive, pass is to reduce the section
2593 * areas to pointers to the actually pinned objects.
2595 SGEN_LOG (6, "Pinning from sections");
2596 /* first pass for the sections */
2597 sgen_find_section_pin_queue_start_end (nursery_section);
2598 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2599 /* identify possible pointers to the insize of large objects */
2600 SGEN_LOG (6, "Pinning from large objects");
2601 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2603 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2604 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2606 #ifdef ENABLE_DTRACE
2607 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2608 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2609 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2613 if (sgen_los_object_is_pinned (bigobj->data)) {
2614 g_assert (finish_up_concurrent_mark);
2617 sgen_los_pin_object (bigobj->data);
2618 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2619 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2620 if (G_UNLIKELY (do_pin_stats))
2621 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2622 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));
2625 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2629 notify_gc_roots (&root_report);
2630 /* second pass for the sections */
2631 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2632 ctx.copy_func = NULL;
2633 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2636 * Concurrent mark never follows references into the nursery.
2637 * In the start and finish pauses we must scan live nursery
2638 * objects, though. We could simply scan all nursery objects,
2639 * but that would be conservative. The easiest way is to do a
2640 * nursery collection, which copies all live nursery objects
2641 * (except pinned ones, with the simple nursery) to the major
2642 * heap. Scanning the mod union table later will then scan
2643 * those promoted objects, provided they're reachable. Pinned
2644 * objects in the nursery - which we can trivially find in the
2645 * pinning queue - are treated as roots in the mark pauses.
2647 * The split nursery complicates the latter part because
2648 * non-pinned objects can survive in the nursery. That's why
2649 * we need to do a full front-to-back scan of the nursery,
2650 * marking all objects.
2652 * Non-concurrent mark evacuates from the nursery, so it's
2653 * sufficient to just scan pinned nursery objects.
2655 if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2656 scan_nursery_objects (ctx);
2658 pin_objects_in_nursery (ctx);
2659 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2660 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2663 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2664 if (old_next_pin_slot)
2665 *old_next_pin_slot = sgen_get_pinned_count ();
2668 time_major_pinning += TV_ELAPSED (atv, btv);
2669 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2670 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2672 major_collector.init_to_space ();
2674 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2675 main_gc_thread = mono_native_thread_self ();
2678 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2679 report_registered_roots ();
2681 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2683 /* registered roots, this includes static fields */
2684 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2685 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2686 scrrjd_normal->scan_func = current_object_ops.scan_object;
2687 scrrjd_normal->heap_start = heap_start;
2688 scrrjd_normal->heap_end = heap_end;
2689 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2690 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2692 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2693 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2694 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2695 scrrjd_wbarrier->heap_start = heap_start;
2696 scrrjd_wbarrier->heap_end = heap_end;
2697 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2698 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2701 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2704 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2705 stdjd->heap_start = heap_start;
2706 stdjd->heap_end = heap_end;
2707 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2710 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2713 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2715 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2716 report_finalizer_roots ();
2718 /* scan the list of objects ready for finalization */
2719 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2720 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2722 if (scan_mod_union) {
2723 g_assert (finish_up_concurrent_mark);
2725 /* Mod union card table */
2726 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2727 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2731 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2732 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2735 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2737 if (concurrent_collection_in_progress) {
2738 /* prepare the pin queue for the next collection */
2739 sgen_finish_pinning ();
2741 sgen_pin_stats_reset ();
2743 if (do_concurrent_checks)
2744 check_nursery_is_clean ();
2749 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2751 MONO_GC_BEGIN (GENERATION_OLD);
2752 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2754 current_collection_generation = GENERATION_OLD;
2755 #ifndef DISABLE_PERFCOUNTERS
2756 mono_perfcounters->gc_collections1++;
2759 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2762 g_assert (major_collector.is_concurrent);
2763 concurrent_collection_in_progress = TRUE;
2765 sgen_cement_concurrent_start ();
2767 current_object_ops = major_collector.major_concurrent_ops;
2769 current_object_ops = major_collector.major_ops;
2772 reset_pinned_from_failed_allocation ();
2774 sgen_memgov_major_collection_start ();
2776 //count_ref_nonref_objs ();
2777 //consistency_check ();
2779 check_scan_starts ();
2782 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2783 gc_stats.major_gc_count ++;
2785 if (major_collector.start_major_collection)
2786 major_collector.start_major_collection ();
2788 major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
2792 wait_for_workers_to_finish (void)
2794 while (!sgen_workers_all_done ())
2801 if (concurrent_collection_in_progress) {
2802 gray_queue_redirect (&gray_queue);
2803 sgen_workers_join ();
2806 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2808 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2809 main_gc_thread = NULL;
2814 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union)
2816 LOSObject *bigobj, *prevbo;
2822 if (concurrent_collection_in_progress)
2825 if (concurrent_collection_in_progress) {
2826 current_object_ops = major_collector.major_concurrent_ops;
2828 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
2831 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2833 if (do_concurrent_checks)
2834 check_nursery_is_clean ();
2836 current_object_ops = major_collector.major_ops;
2840 * The workers have stopped so we need to finish gray queue
2841 * work that might result from finalization in the main GC
2842 * thread. Redirection must therefore be turned off.
2844 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2845 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2847 /* all the objects in the heap */
2848 finish_gray_stack (GENERATION_OLD, &gray_queue);
2850 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2853 * The (single-threaded) finalization code might have done
2854 * some copying/marking so we can only reset the GC thread's
2855 * worker data here instead of earlier when we joined the
2858 sgen_workers_reset_data ();
2860 if (objects_pinned) {
2861 g_assert (!concurrent_collection_in_progress);
2863 /*This is slow, but we just OOM'd*/
2864 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2865 sgen_optimize_pin_queue ();
2866 sgen_find_section_pin_queue_start_end (nursery_section);
2870 reset_heap_boundaries ();
2871 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2873 if (check_mark_bits_after_major_collection)
2874 sgen_check_major_heap_marked ();
2876 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2878 /* sweep the big objects list */
2880 for (bigobj = los_object_list; bigobj;) {
2881 g_assert (!object_is_pinned (bigobj->data));
2882 if (sgen_los_object_is_pinned (bigobj->data)) {
2883 sgen_los_unpin_object (bigobj->data);
2884 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2887 /* not referenced anywhere, so we can free it */
2889 prevbo->next = bigobj->next;
2891 los_object_list = bigobj->next;
2893 bigobj = bigobj->next;
2894 sgen_los_free_object (to_free);
2898 bigobj = bigobj->next;
2902 time_major_free_bigobjs += TV_ELAPSED (atv, btv);
2907 time_major_los_sweep += TV_ELAPSED (btv, atv);
2909 major_collector.sweep ();
2911 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2914 time_major_sweep += TV_ELAPSED (atv, btv);
2916 if (!concurrent_collection_in_progress) {
2917 /* walk the pin_queue, build up the fragment list of free memory, unmark
2918 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2921 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
2924 /* prepare the pin queue for the next collection */
2925 sgen_finish_pinning ();
2927 /* Clear TLABs for all threads */
2928 sgen_clear_tlabs ();
2930 sgen_pin_stats_reset ();
2933 if (concurrent_collection_in_progress)
2934 sgen_cement_concurrent_finish ();
2935 sgen_cement_clear_below_threshold ();
2938 time_major_fragment_creation += TV_ELAPSED (btv, atv);
2941 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2943 if (fin_ready_list || critical_fin_list) {
2944 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2945 mono_gc_finalize_notify ();
2948 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2950 sgen_memgov_major_collection_end ();
2951 current_collection_generation = -1;
2953 major_collector.finish_major_collection ();
2955 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2957 if (concurrent_collection_in_progress)
2958 concurrent_collection_in_progress = FALSE;
2960 check_scan_starts ();
2962 binary_protocol_flush_buffers (FALSE);
2964 //consistency_check ();
2966 MONO_GC_END (GENERATION_OLD);
2967 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD);
2971 major_do_collection (const char *reason)
2973 TV_DECLARE (time_start);
2974 TV_DECLARE (time_end);
2975 size_t old_next_pin_slot;
2977 if (disable_major_collections)
2980 if (major_collector.get_and_reset_num_major_objects_marked) {
2981 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2982 g_assert (!num_marked);
2985 /* world must be stopped already */
2986 TV_GETTIME (time_start);
2988 major_start_collection (FALSE, &old_next_pin_slot);
2989 major_finish_collection (reason, old_next_pin_slot, FALSE);
2991 TV_GETTIME (time_end);
2992 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2994 /* FIXME: also report this to the user, preferably in gc-end. */
2995 if (major_collector.get_and_reset_num_major_objects_marked)
2996 major_collector.get_and_reset_num_major_objects_marked ();
2998 return bytes_pinned_from_failed_allocation > 0;
3002 major_start_concurrent_collection (const char *reason)
3004 TV_DECLARE (time_start);
3005 TV_DECLARE (time_end);
3006 long long num_objects_marked;
3008 if (disable_major_collections)
3011 TV_GETTIME (time_start);
3012 SGEN_TV_GETTIME (time_major_conc_collection_start);
3014 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3015 g_assert (num_objects_marked == 0);
3017 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3018 binary_protocol_concurrent_start ();
3020 // FIXME: store reason and pass it when finishing
3021 major_start_collection (TRUE, NULL);
3023 gray_queue_redirect (&gray_queue);
3024 sgen_workers_wait_for_jobs ();
3026 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3027 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3029 TV_GETTIME (time_end);
3030 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3032 current_collection_generation = -1;
3036 major_update_or_finish_concurrent_collection (gboolean force_finish)
3038 TV_DECLARE (total_start);
3039 TV_DECLARE (total_end);
3040 SgenGrayQueue unpin_queue;
3041 memset (&unpin_queue, 0, sizeof (unpin_queue));
3043 TV_GETTIME (total_start);
3045 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3046 binary_protocol_concurrent_update_finish ();
3048 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3050 if (!force_finish && !sgen_workers_all_done ()) {
3051 major_collector.update_cardtable_mod_union ();
3052 sgen_los_update_cardtable_mod_union ();
3054 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3056 TV_GETTIME (total_end);
3057 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3063 * The major collector can add global remsets which are processed in the finishing
3064 * nursery collection, below. That implies that the workers must have finished
3065 * marking before the nursery collection is allowed to run, otherwise we might miss
3068 wait_for_workers_to_finish ();
3070 SGEN_TV_GETTIME (time_major_conc_collection_end);
3071 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3073 major_collector.update_cardtable_mod_union ();
3074 sgen_los_update_cardtable_mod_union ();
3076 collect_nursery (&unpin_queue, TRUE);
3078 if (mod_union_consistency_check)
3079 sgen_check_mod_union_consistency ();
3081 current_collection_generation = GENERATION_OLD;
3082 major_finish_collection ("finishing", -1, TRUE);
3084 if (whole_heap_check_before_collection)
3085 sgen_check_whole_heap (FALSE);
3087 unpin_objects_from_queue (&unpin_queue);
3088 sgen_gray_object_queue_deinit (&unpin_queue);
3090 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3092 TV_GETTIME (total_end);
3093 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3095 current_collection_generation = -1;
3101 * Ensure an allocation request for @size will succeed by freeing enough memory.
3103 * LOCKING: The GC lock MUST be held.
3106 sgen_ensure_free_space (size_t size)
3108 int generation_to_collect = -1;
3109 const char *reason = NULL;
3112 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3113 if (sgen_need_major_collection (size)) {
3114 reason = "LOS overflow";
3115 generation_to_collect = GENERATION_OLD;
3118 if (degraded_mode) {
3119 if (sgen_need_major_collection (size)) {
3120 reason = "Degraded mode overflow";
3121 generation_to_collect = GENERATION_OLD;
3123 } else if (sgen_need_major_collection (size)) {
3124 reason = "Minor allowance";
3125 generation_to_collect = GENERATION_OLD;
3127 generation_to_collect = GENERATION_NURSERY;
3128 reason = "Nursery full";
3132 if (generation_to_collect == -1) {
3133 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3134 generation_to_collect = GENERATION_OLD;
3135 reason = "Finish concurrent collection";
3139 if (generation_to_collect == -1)
3141 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3145 * LOCKING: Assumes the GC lock is held.
3148 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3150 TV_DECLARE (gc_end);
3151 TV_DECLARE (gc_total_start);
3152 TV_DECLARE (gc_total_end);
3153 GGTimingInfo infos [2];
3154 int overflow_generation_to_collect = -1;
3155 int oldest_generation_collected = generation_to_collect;
3156 const char *overflow_reason = NULL;
3158 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3160 binary_protocol_collection_force (generation_to_collect);
3162 g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3164 memset (infos, 0, sizeof (infos));
3165 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3167 infos [0].generation = generation_to_collect;
3168 infos [0].reason = reason;
3169 infos [0].is_overflow = FALSE;
3170 TV_GETTIME (infos [0].total_time);
3171 infos [1].generation = -1;
3173 sgen_stop_world (generation_to_collect);
3175 TV_GETTIME (gc_total_start);
3177 if (concurrent_collection_in_progress) {
3178 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3179 oldest_generation_collected = GENERATION_OLD;
3182 if (generation_to_collect == GENERATION_OLD)
3185 if (generation_to_collect == GENERATION_OLD &&
3186 allow_synchronous_major &&
3187 major_collector.want_synchronous_collection &&
3188 *major_collector.want_synchronous_collection) {
3189 wait_to_finish = TRUE;
3193 //FIXME extract overflow reason
3194 if (generation_to_collect == GENERATION_NURSERY) {
3195 if (collect_nursery (NULL, FALSE)) {
3196 overflow_generation_to_collect = GENERATION_OLD;
3197 overflow_reason = "Minor overflow";
3200 if (major_collector.is_concurrent) {
3201 g_assert (!concurrent_collection_in_progress);
3202 if (!wait_to_finish)
3203 collect_nursery (NULL, FALSE);
3206 if (major_collector.is_concurrent && !wait_to_finish) {
3207 major_start_concurrent_collection (reason);
3208 // FIXME: set infos[0] properly
3211 if (major_do_collection (reason)) {
3212 overflow_generation_to_collect = GENERATION_NURSERY;
3213 overflow_reason = "Excessive pinning";
3218 TV_GETTIME (gc_end);
3219 infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3222 if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3223 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3224 infos [1].generation = overflow_generation_to_collect;
3225 infos [1].reason = overflow_reason;
3226 infos [1].is_overflow = TRUE;
3227 infos [1].total_time = gc_end;
3229 if (overflow_generation_to_collect == GENERATION_NURSERY)
3230 collect_nursery (NULL, FALSE);
3232 major_do_collection (overflow_reason);
3234 TV_GETTIME (gc_end);
3235 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3237 /* keep events symmetric */
3238 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3240 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3243 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3245 /* this also sets the proper pointers for the next allocation */
3246 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3247 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3248 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3249 sgen_dump_pin_queue ();
3254 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3256 TV_GETTIME (gc_total_end);
3257 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3259 sgen_restart_world (oldest_generation_collected, infos);
3261 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3265 * ######################################################################
3266 * ######## Memory allocation from the OS
3267 * ######################################################################
3268 * This section of code deals with getting memory from the OS and
3269 * allocating memory for GC-internal data structures.
3270 * Internal memory can be handled with a freelist for small objects.
3276 G_GNUC_UNUSED static void
3277 report_internal_mem_usage (void)
3279 printf ("Internal memory usage:\n");
3280 sgen_report_internal_mem_usage ();
3281 printf ("Pinned memory usage:\n");
3282 major_collector.report_pinned_memory_usage ();
3286 * ######################################################################
3287 * ######## Finalization support
3288 * ######################################################################
3291 static inline gboolean
3292 sgen_major_is_object_alive (void *object)
3296 /* Oldgen objects can be pinned and forwarded too */
3297 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3301 * FIXME: major_collector.is_object_live() also calculates the
3302 * size. Avoid the double calculation.
3304 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3305 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3306 return sgen_los_object_is_pinned (object);
3308 return major_collector.is_object_live (object);
3312 * If the object has been forwarded it means it's still referenced from a root.
3313 * If it is pinned it's still alive as well.
3314 * A LOS object is only alive if we have pinned it.
3315 * Return TRUE if @obj is ready to be finalized.
3317 static inline gboolean
3318 sgen_is_object_alive (void *object)
3320 if (ptr_in_nursery (object))
3321 return sgen_nursery_is_object_alive (object);
3323 return sgen_major_is_object_alive (object);
3327 * This function returns true if @object is either alive or it belongs to the old gen
3328 * and we're currently doing a minor collection.
3331 sgen_is_object_alive_for_current_gen (char *object)
3333 if (ptr_in_nursery (object))
3334 return sgen_nursery_is_object_alive (object);
3336 if (current_collection_generation == GENERATION_NURSERY)
3339 return sgen_major_is_object_alive (object);
3343 * This function returns true if @object is either alive and belongs to the
3344 * current collection - major collections are full heap, so old gen objects
3345 * are never alive during a minor collection.
3348 sgen_is_object_alive_and_on_current_collection (char *object)
3350 if (ptr_in_nursery (object))
3351 return sgen_nursery_is_object_alive (object);
3353 if (current_collection_generation == GENERATION_NURSERY)
3356 return sgen_major_is_object_alive (object);
3361 sgen_gc_is_object_ready_for_finalization (void *object)
3363 return !sgen_is_object_alive (object);
3367 has_critical_finalizer (MonoObject *obj)
3371 if (!mono_defaults.critical_finalizer_object)
3374 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3376 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3380 is_finalization_aware (MonoObject *obj)
3382 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3383 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3387 sgen_queue_finalization_entry (MonoObject *obj)
3389 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3390 gboolean critical = has_critical_finalizer (obj);
3391 entry->object = obj;
3393 entry->next = critical_fin_list;
3394 critical_fin_list = entry;
3396 entry->next = fin_ready_list;
3397 fin_ready_list = entry;
3400 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3401 fin_callbacks.object_queued_for_finalization (obj);
3403 #ifdef ENABLE_DTRACE
3404 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3405 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3406 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3407 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3408 vt->klass->name_space, vt->klass->name, gen, critical);
3414 sgen_object_is_live (void *obj)
3416 return sgen_is_object_alive_and_on_current_collection (obj);
3419 /* LOCKING: requires that the GC lock is held */
3421 null_ephemerons_for_domain (MonoDomain *domain)
3423 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3426 MonoObject *object = (MonoObject*)current->array;
3428 if (object && !object->vtable) {
3429 EphemeronLinkNode *tmp = current;
3432 prev->next = current->next;
3434 ephemeron_list = current->next;
3436 current = current->next;
3437 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3440 current = current->next;
3445 /* LOCKING: requires that the GC lock is held */
3447 clear_unreachable_ephemerons (ScanCopyContext ctx)
3449 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3450 GrayQueue *queue = ctx.queue;
3451 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3453 Ephemeron *cur, *array_end;
3457 char *object = current->array;
3459 if (!sgen_is_object_alive_for_current_gen (object)) {
3460 EphemeronLinkNode *tmp = current;
3462 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3465 prev->next = current->next;
3467 ephemeron_list = current->next;
3469 current = current->next;
3470 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3475 copy_func ((void**)&object, queue);
3476 current->array = object;
3478 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3480 array = (MonoArray*)object;
3481 cur = mono_array_addr (array, Ephemeron, 0);
3482 array_end = cur + mono_array_length_fast (array);
3483 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3485 for (; cur < array_end; ++cur) {
3486 char *key = (char*)cur->key;
3488 if (!key || key == tombstone)
3491 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3492 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3493 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3495 if (!sgen_is_object_alive_for_current_gen (key)) {
3496 cur->key = tombstone;
3502 current = current->next;
3507 LOCKING: requires that the GC lock is held
3509 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3512 mark_ephemerons_in_range (ScanCopyContext ctx)
3514 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3515 GrayQueue *queue = ctx.queue;
3516 int nothing_marked = 1;
3517 EphemeronLinkNode *current = ephemeron_list;
3519 Ephemeron *cur, *array_end;
3522 for (current = ephemeron_list; current; current = current->next) {
3523 char *object = current->array;
3524 SGEN_LOG (5, "Ephemeron array at %p", object);
3526 /*It has to be alive*/
3527 if (!sgen_is_object_alive_for_current_gen (object)) {
3528 SGEN_LOG (5, "\tnot reachable");
3532 copy_func ((void**)&object, queue);
3534 array = (MonoArray*)object;
3535 cur = mono_array_addr (array, Ephemeron, 0);
3536 array_end = cur + mono_array_length_fast (array);
3537 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3539 for (; cur < array_end; ++cur) {
3540 char *key = cur->key;
3542 if (!key || key == tombstone)
3545 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3546 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3547 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3549 if (sgen_is_object_alive_for_current_gen (key)) {
3550 char *value = cur->value;
3552 copy_func ((void**)&cur->key, queue);
3554 if (!sgen_is_object_alive_for_current_gen (value))
3556 copy_func ((void**)&cur->value, queue);
3562 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3563 return nothing_marked;
3567 mono_gc_invoke_finalizers (void)
3569 FinalizeReadyEntry *entry = NULL;
3570 gboolean entry_is_critical = FALSE;
3573 /* FIXME: batch to reduce lock contention */
3574 while (fin_ready_list || critical_fin_list) {
3578 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3580 /* We have finalized entry in the last
3581 interation, now we need to remove it from
3584 *list = entry->next;
3586 FinalizeReadyEntry *e = *list;
3587 while (e->next != entry)
3589 e->next = entry->next;
3591 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3595 /* Now look for the first non-null entry. */
3596 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3599 entry_is_critical = FALSE;
3601 entry_is_critical = TRUE;
3602 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3607 g_assert (entry->object);
3608 num_ready_finalizers--;
3609 obj = entry->object;
3610 entry->object = NULL;
3611 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3619 g_assert (entry->object == NULL);
3621 /* the object is on the stack so it is pinned */
3622 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3623 mono_gc_run_finalize (obj, NULL);
3630 mono_gc_pending_finalizers (void)
3632 return fin_ready_list || critical_fin_list;
3636 * ######################################################################
3637 * ######## registered roots support
3638 * ######################################################################
3642 * We do not coalesce roots.
3645 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3647 RootRecord new_root;
3650 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3651 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3652 /* we allow changing the size and the descriptor (for thread statics etc) */
3654 size_t old_size = root->end_root - start;
3655 root->end_root = start + size;
3656 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3657 ((root->root_desc == 0) && (descr == NULL)));
3658 root->root_desc = (mword)descr;
3660 roots_size -= old_size;
3666 new_root.end_root = start + size;
3667 new_root.root_desc = (mword)descr;
3669 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3672 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);
3679 mono_gc_register_root (char *start, size_t size, void *descr)
3681 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3685 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3687 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3691 mono_gc_deregister_root (char* addr)
3697 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3698 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3699 roots_size -= (root.end_root - addr);
3705 * ######################################################################
3706 * ######## Thread handling (stop/start code)
3707 * ######################################################################
3710 unsigned int sgen_global_stop_count = 0;
3713 sgen_get_current_collection_generation (void)
3715 return current_collection_generation;
3719 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3721 gc_callbacks = *callbacks;
3725 mono_gc_get_gc_callbacks ()
3727 return &gc_callbacks;
3730 /* Variables holding start/end nursery so it won't have to be passed at every call */
3731 static void *scan_area_arg_start, *scan_area_arg_end;
3734 mono_gc_conservatively_scan_area (void *start, void *end)
3736 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3740 mono_gc_scan_object (void *obj, void *gc_data)
3742 UserCopyOrMarkData *data = gc_data;
3743 current_object_ops.copy_or_mark_object (&obj, data->queue);
3748 * Mark from thread stacks and registers.
3751 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3753 SgenThreadInfo *info;
3755 scan_area_arg_start = start_nursery;
3756 scan_area_arg_end = end_nursery;
3758 FOREACH_THREAD (info) {
3760 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);
3763 if (info->gc_disabled) {
3764 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);
3767 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3768 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));
3771 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 ());
3772 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3773 UserCopyOrMarkData data = { NULL, queue };
3774 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3775 } else if (!precise) {
3776 if (!conservative_stack_mark) {
3777 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3778 conservative_stack_mark = TRUE;
3780 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3785 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3786 start_nursery, end_nursery, PIN_TYPE_STACK);
3788 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3789 start_nursery, end_nursery, PIN_TYPE_STACK);
3792 } END_FOREACH_THREAD
3796 ptr_on_stack (void *ptr)
3798 gpointer stack_start = &stack_start;
3799 SgenThreadInfo *info = mono_thread_info_current ();
3801 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3807 sgen_thread_register (SgenThreadInfo* info, void *addr)
3810 guint8 *staddr = NULL;
3812 #ifndef HAVE_KW_THREAD
3813 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3815 g_assert (!mono_native_tls_get_value (thread_info_key));
3816 mono_native_tls_set_value (thread_info_key, info);
3818 sgen_thread_info = info;
3821 #ifdef SGEN_POSIX_STW
3822 info->stop_count = -1;
3826 info->stack_start = NULL;
3827 info->stopped_ip = NULL;
3828 info->stopped_domain = NULL;
3830 memset (&info->ctx, 0, sizeof (MonoContext));
3832 memset (&info->regs, 0, sizeof (info->regs));
3835 sgen_init_tlab_info (info);
3837 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3839 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3840 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3843 info->stack_start_limit = staddr;
3845 info->stack_end = staddr + stsize;
3847 gsize stack_bottom = (gsize)addr;
3848 stack_bottom += 4095;
3849 stack_bottom &= ~4095;
3850 info->stack_end = (char*)stack_bottom;
3853 #ifdef HAVE_KW_THREAD
3854 stack_end = info->stack_end;
3857 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3859 if (gc_callbacks.thread_attach_func)
3860 info->runtime_data = gc_callbacks.thread_attach_func ();
3865 sgen_thread_detach (SgenThreadInfo *p)
3867 /* If a delegate is passed to native code and invoked on a thread we dont
3868 * know about, the jit will register it with mono_jit_thread_attach, but
3869 * we have no way of knowing when that thread goes away. SGen has a TSD
3870 * so we assume that if the domain is still registered, we can detach
3873 if (mono_domain_get ())
3874 mono_thread_detach_internal (mono_thread_internal_current ());
3878 sgen_thread_unregister (SgenThreadInfo *p)
3880 MonoNativeThreadId tid;
3882 tid = mono_thread_info_get_tid (p);
3883 binary_protocol_thread_unregister ((gpointer)tid);
3884 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3886 #ifndef HAVE_KW_THREAD
3887 mono_native_tls_set_value (thread_info_key, NULL);
3889 sgen_thread_info = NULL;
3892 if (p->info.runtime_thread)
3893 mono_threads_add_joinable_thread ((gpointer)tid);
3895 if (gc_callbacks.thread_detach_func) {
3896 gc_callbacks.thread_detach_func (p->runtime_data);
3897 p->runtime_data = NULL;
3903 sgen_thread_attach (SgenThreadInfo *info)
3906 /*this is odd, can we get attached before the gc is inited?*/
3910 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3911 info->runtime_data = gc_callbacks.thread_attach_func ();
3914 mono_gc_register_thread (void *baseptr)
3916 return mono_thread_info_attach (baseptr) != NULL;
3920 * mono_gc_set_stack_end:
3922 * Set the end of the current threads stack to STACK_END. The stack space between
3923 * STACK_END and the real end of the threads stack will not be scanned during collections.
3926 mono_gc_set_stack_end (void *stack_end)
3928 SgenThreadInfo *info;
3931 info = mono_thread_info_current ();
3933 g_assert (stack_end < info->stack_end);
3934 info->stack_end = stack_end;
3939 #if USE_PTHREAD_INTERCEPT
3943 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3945 return pthread_create (new_thread, attr, start_routine, arg);
3949 mono_gc_pthread_join (pthread_t thread, void **retval)
3951 return pthread_join (thread, retval);
3955 mono_gc_pthread_detach (pthread_t thread)
3957 return pthread_detach (thread);
3961 mono_gc_pthread_exit (void *retval)
3963 mono_thread_info_detach ();
3964 pthread_exit (retval);
3965 g_assert_not_reached ();
3968 #endif /* USE_PTHREAD_INTERCEPT */
3971 * ######################################################################
3972 * ######## Write barriers
3973 * ######################################################################
3977 * Note: the write barriers first do the needed GC work and then do the actual store:
3978 * this way the value is visible to the conservative GC scan after the write barrier
3979 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
3980 * the conservative scan, otherwise by the remembered set scan.
3983 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
3985 HEAVY_STAT (++stat_wbarrier_set_field);
3986 if (ptr_in_nursery (field_ptr)) {
3987 *(void**)field_ptr = value;
3990 SGEN_LOG (8, "Adding remset at %p", field_ptr);
3992 binary_protocol_wbarrier (field_ptr, value, value->vtable);
3994 remset.wbarrier_set_field (obj, field_ptr, value);
3998 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4000 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4001 if (ptr_in_nursery (slot_ptr)) {
4002 *(void**)slot_ptr = value;
4005 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4007 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4009 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4013 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4015 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4016 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4017 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4018 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4022 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4023 if (binary_protocol_is_heavy_enabled ()) {
4025 for (i = 0; i < count; ++i) {
4026 gpointer dest = (gpointer*)dest_ptr + i;
4027 gpointer obj = *((gpointer*)src_ptr + i);
4029 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4034 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4037 static char *found_obj;
4040 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4042 char *ptr = user_data;
4044 if (ptr >= obj && ptr < obj + size) {
4045 g_assert (!found_obj);
4050 /* for use in the debugger */
4051 char* find_object_for_ptr (char *ptr);
4053 find_object_for_ptr (char *ptr)
4055 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4057 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4058 find_object_for_ptr_callback, ptr, TRUE);
4064 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4069 * Very inefficient, but this is debugging code, supposed to
4070 * be called from gdb, so we don't care.
4073 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4078 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4082 HEAVY_STAT (++stat_wbarrier_generic_store);
4084 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4085 /* FIXME: ptr_in_heap must be called with the GC lock held */
4086 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4087 char *start = find_object_for_ptr (ptr);
4088 MonoObject *value = *(MonoObject**)ptr;
4092 MonoObject *obj = (MonoObject*)start;
4093 if (obj->vtable->domain != value->vtable->domain)
4094 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4100 obj = *(gpointer*)ptr;
4102 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4104 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4105 SGEN_LOG (8, "Skipping remset at %p", ptr);
4110 * We need to record old->old pointer locations for the
4111 * concurrent collector.
4113 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4114 SGEN_LOG (8, "Skipping remset at %p", ptr);
4118 SGEN_LOG (8, "Adding remset at %p", ptr);
4120 remset.wbarrier_generic_nostore (ptr);
4124 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4126 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4127 *(void**)ptr = value;
4128 if (ptr_in_nursery (value))
4129 mono_gc_wbarrier_generic_nostore (ptr);
4130 sgen_dummy_use (value);
4133 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4134 * as an atomic operation with release semantics.
4137 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4139 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4141 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4143 InterlockedWritePointer (ptr, value);
4145 if (ptr_in_nursery (value))
4146 mono_gc_wbarrier_generic_nostore (ptr);
4148 sgen_dummy_use (value);
4151 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4153 mword *dest = _dest;
4158 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4163 size -= SIZEOF_VOID_P;
4168 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4170 #define HANDLE_PTR(ptr,obj) do { \
4171 gpointer o = *(gpointer*)(ptr); \
4173 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4174 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4179 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4181 #define SCAN_OBJECT_NOVTABLE
4182 #include "sgen-scan-object.h"
4187 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4189 HEAVY_STAT (++stat_wbarrier_value_copy);
4190 g_assert (klass->valuetype);
4192 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4194 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4195 size_t element_size = mono_class_value_size (klass, NULL);
4196 size_t size = count * element_size;
4197 mono_gc_memmove_atomic (dest, src, size);
4201 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4202 if (binary_protocol_is_heavy_enabled ()) {
4203 size_t element_size = mono_class_value_size (klass, NULL);
4205 for (i = 0; i < count; ++i) {
4206 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4207 (char*)src + i * element_size - sizeof (MonoObject),
4208 (mword) klass->gc_descr);
4213 remset.wbarrier_value_copy (dest, src, count, klass);
4217 * mono_gc_wbarrier_object_copy:
4219 * Write barrier to call when obj is the result of a clone or copy of an object.
4222 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4226 HEAVY_STAT (++stat_wbarrier_object_copy);
4228 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4229 size = mono_object_class (obj)->instance_size;
4230 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4231 size - sizeof (MonoObject));
4235 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4236 if (binary_protocol_is_heavy_enabled ())
4237 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4240 remset.wbarrier_object_copy (obj, src);
4245 * ######################################################################
4246 * ######## Other mono public interface functions.
4247 * ######################################################################
4250 #define REFS_SIZE 128
4253 MonoGCReferences callback;
4257 MonoObject *refs [REFS_SIZE];
4258 uintptr_t offsets [REFS_SIZE];
4262 #define HANDLE_PTR(ptr,obj) do { \
4264 if (hwi->count == REFS_SIZE) { \
4265 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4269 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4270 hwi->refs [hwi->count++] = *(ptr); \
4275 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4277 mword desc = sgen_obj_get_descriptor (start);
4279 #include "sgen-scan-object.h"
4283 walk_references (char *start, size_t size, void *data)
4285 HeapWalkInfo *hwi = data;
4288 collect_references (hwi, start, size);
4289 if (hwi->count || !hwi->called)
4290 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4294 * mono_gc_walk_heap:
4295 * @flags: flags for future use
4296 * @callback: a function pointer called for each object in the heap
4297 * @data: a user data pointer that is passed to callback
4299 * This function can be used to iterate over all the live objects in the heap:
4300 * for each object, @callback is invoked, providing info about the object's
4301 * location in memory, its class, its size and the objects it references.
4302 * For each referenced object it's offset from the object address is
4303 * reported in the offsets array.
4304 * The object references may be buffered, so the callback may be invoked
4305 * multiple times for the same object: in all but the first call, the size
4306 * argument will be zero.
4307 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4308 * profiler event handler.
4310 * Returns: a non-zero value if the GC doesn't support heap walking
4313 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4318 hwi.callback = callback;
4321 sgen_clear_nursery_fragments ();
4322 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4324 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4325 sgen_los_iterate_objects (walk_references, &hwi);
4331 mono_gc_collect (int generation)
4336 sgen_perform_collection (0, generation, "user request", TRUE);
4341 mono_gc_max_generation (void)
4347 mono_gc_collection_count (int generation)
4349 if (generation == 0)
4350 return gc_stats.minor_gc_count;
4351 return gc_stats.major_gc_count;
4355 mono_gc_get_used_size (void)
4359 tot = los_memory_usage;
4360 tot += nursery_section->next_data - nursery_section->data;
4361 tot += major_collector.get_used_size ();
4362 /* FIXME: account for pinned objects */
4368 mono_gc_get_los_limit (void)
4370 return MAX_SMALL_OBJ_SIZE;
4374 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4376 mono_unichar2 *new_end = str->chars + new_length;
4378 /* zero the discarded string. This null-delimits the string and allows
4379 * the space to be reclaimed by SGen. */
4381 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4382 CHECK_CANARY_FOR_OBJECT (str);
4383 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4384 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4386 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4389 str->length = new_length;
4393 mono_gc_user_markers_supported (void)
4399 mono_object_is_alive (MonoObject* o)
4405 mono_gc_get_generation (MonoObject *obj)
4407 if (ptr_in_nursery (obj))
4413 mono_gc_enable_events (void)
4418 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4420 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4424 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4426 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4430 mono_gc_weak_link_get (void **link_addr)
4432 void * volatile *link_addr_volatile;
4436 link_addr_volatile = link_addr;
4437 ptr = (void*)*link_addr_volatile;
4439 * At this point we have a hidden pointer. If the GC runs
4440 * here, it will not recognize the hidden pointer as a
4441 * reference, and if the object behind it is not referenced
4442 * elsewhere, it will be freed. Once the world is restarted
4443 * we reveal the pointer, giving us a pointer to a freed
4444 * object. To make sure we don't return it, we load the
4445 * hidden pointer again. If it's still the same, we can be
4446 * sure the object reference is valid.
4449 obj = (MonoObject*) REVEAL_POINTER (ptr);
4453 mono_memory_barrier ();
4456 * During the second bridge processing step the world is
4457 * running again. That step processes all weak links once
4458 * more to null those that refer to dead objects. Before that
4459 * is completed, those links must not be followed, so we
4460 * conservatively wait for bridge processing when any weak
4461 * link is dereferenced.
4463 if (G_UNLIKELY (bridge_processing_in_progress))
4464 mono_gc_wait_for_bridge_processing ();
4466 if ((void*)*link_addr_volatile != ptr)
4473 mono_gc_ephemeron_array_add (MonoObject *obj)
4475 EphemeronLinkNode *node;
4479 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4484 node->array = (char*)obj;
4485 node->next = ephemeron_list;
4486 ephemeron_list = node;
4488 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4495 mono_gc_set_allow_synchronous_major (gboolean flag)
4497 if (!major_collector.is_concurrent)
4500 allow_synchronous_major = flag;
4505 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4509 result = func (data);
4510 UNLOCK_INTERRUPTION;
4515 mono_gc_is_gc_thread (void)
4519 result = mono_thread_info_current () != NULL;
4525 is_critical_method (MonoMethod *method)
4527 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4531 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4535 va_start (ap, description_format);
4537 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4538 vfprintf (stderr, description_format, ap);
4540 fprintf (stderr, " - %s", fallback);
4541 fprintf (stderr, "\n");
4547 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4550 double val = strtod (opt, &endptr);
4551 if (endptr == opt) {
4552 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4555 else if (val < min || val > max) {
4556 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4564 mono_gc_base_init (void)
4566 MonoThreadInfoCallbacks cb;
4569 char *major_collector_opt = NULL;
4570 char *minor_collector_opt = NULL;
4571 size_t max_heap = 0;
4572 size_t soft_limit = 0;
4575 gboolean debug_print_allowance = FALSE;
4576 double allowance_ratio = 0, save_target = 0;
4577 gboolean have_split_nursery = FALSE;
4578 gboolean cement_enabled = TRUE;
4581 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4584 /* already inited */
4587 /* being inited by another thread */
4591 /* we will init it */
4594 g_assert_not_reached ();
4596 } while (result != 0);
4598 SGEN_TV_GETTIME (sgen_init_timestamp);
4600 LOCK_INIT (gc_mutex);
4602 pagesize = mono_pagesize ();
4603 gc_debug_file = stderr;
4605 cb.thread_register = sgen_thread_register;
4606 cb.thread_detach = sgen_thread_detach;
4607 cb.thread_unregister = sgen_thread_unregister;
4608 cb.thread_attach = sgen_thread_attach;
4609 cb.mono_method_is_critical = (gpointer)is_critical_method;
4611 cb.thread_exit = mono_gc_pthread_exit;
4612 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4615 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4617 LOCK_INIT (sgen_interruption_mutex);
4618 LOCK_INIT (pin_queue_mutex);
4620 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4621 opts = g_strsplit (env, ",", -1);
4622 for (ptr = opts; *ptr; ++ptr) {
4624 if (g_str_has_prefix (opt, "major=")) {
4625 opt = strchr (opt, '=') + 1;
4626 major_collector_opt = g_strdup (opt);
4627 } else if (g_str_has_prefix (opt, "minor=")) {
4628 opt = strchr (opt, '=') + 1;
4629 minor_collector_opt = g_strdup (opt);
4637 sgen_init_internal_allocator ();
4638 sgen_init_nursery_allocator ();
4639 sgen_init_fin_weak_hash ();
4641 sgen_init_hash_table ();
4642 sgen_init_descriptors ();
4643 sgen_init_gray_queues ();
4645 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4646 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4647 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4648 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4650 #ifndef HAVE_KW_THREAD
4651 mono_native_tls_alloc (&thread_info_key, NULL);
4652 #if defined(__APPLE__) || defined (HOST_WIN32)
4654 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4655 * where the two are the same.
4657 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4661 int tls_offset = -1;
4662 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4663 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4668 * This needs to happen before any internal allocations because
4669 * it inits the small id which is required for hazard pointer
4674 mono_thread_info_attach (&dummy);
4676 if (!minor_collector_opt) {
4677 sgen_simple_nursery_init (&sgen_minor_collector);
4679 if (!strcmp (minor_collector_opt, "simple")) {
4681 sgen_simple_nursery_init (&sgen_minor_collector);
4682 } else if (!strcmp (minor_collector_opt, "split")) {
4683 sgen_split_nursery_init (&sgen_minor_collector);
4684 have_split_nursery = TRUE;
4686 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4687 goto use_simple_nursery;
4691 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4692 use_marksweep_major:
4693 sgen_marksweep_init (&major_collector);
4694 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4695 sgen_marksweep_conc_init (&major_collector);
4697 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4698 goto use_marksweep_major;
4701 ///* Keep this the default for now */
4702 /* Precise marking is broken on all supported targets. Disable until fixed. */
4703 conservative_stack_mark = TRUE;
4705 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4708 gboolean usage_printed = FALSE;
4710 for (ptr = opts; *ptr; ++ptr) {
4712 if (!strcmp (opt, ""))
4714 if (g_str_has_prefix (opt, "major="))
4716 if (g_str_has_prefix (opt, "minor="))
4718 if (g_str_has_prefix (opt, "max-heap-size=")) {
4719 size_t max_heap_candidate = 0;
4720 opt = strchr (opt, '=') + 1;
4721 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4722 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4723 if (max_heap != max_heap_candidate)
4724 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4726 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4730 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4731 opt = strchr (opt, '=') + 1;
4732 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4733 if (soft_limit <= 0) {
4734 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4738 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4742 if (g_str_has_prefix (opt, "stack-mark=")) {
4743 opt = strchr (opt, '=') + 1;
4744 if (!strcmp (opt, "precise")) {
4745 conservative_stack_mark = FALSE;
4746 } else if (!strcmp (opt, "conservative")) {
4747 conservative_stack_mark = TRUE;
4749 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4750 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4754 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4755 opt = strchr (opt, '=') + 1;
4756 sgen_set_bridge_implementation (opt);
4759 if (g_str_has_prefix (opt, "toggleref-test")) {
4760 sgen_register_test_toggleref_callback ();
4765 if (g_str_has_prefix (opt, "nursery-size=")) {
4767 opt = strchr (opt, '=') + 1;
4768 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4769 #ifdef SGEN_ALIGN_NURSERY
4770 if ((val & (val - 1))) {
4771 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4775 if (val < SGEN_MAX_NURSERY_WASTE) {
4776 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4777 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4781 sgen_nursery_size = val;
4782 sgen_nursery_bits = 0;
4783 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4786 sgen_nursery_size = val;
4789 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4795 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4797 opt = strchr (opt, '=') + 1;
4798 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4799 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4804 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4806 opt = strchr (opt, '=') + 1;
4807 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4808 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4809 allowance_ratio = val;
4813 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4814 if (!major_collector.is_concurrent) {
4815 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4819 opt = strchr (opt, '=') + 1;
4821 if (!strcmp (opt, "yes")) {
4822 allow_synchronous_major = TRUE;
4823 } else if (!strcmp (opt, "no")) {
4824 allow_synchronous_major = FALSE;
4826 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4831 if (!strcmp (opt, "cementing")) {
4832 cement_enabled = TRUE;
4835 if (!strcmp (opt, "no-cementing")) {
4836 cement_enabled = FALSE;
4840 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4843 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4846 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4851 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4852 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4853 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4854 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4855 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4856 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4857 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4858 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4859 fprintf (stderr, " [no-]cementing\n");
4860 if (major_collector.is_concurrent)
4861 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4862 if (major_collector.print_gc_param_usage)
4863 major_collector.print_gc_param_usage ();
4864 if (sgen_minor_collector.print_gc_param_usage)
4865 sgen_minor_collector.print_gc_param_usage ();
4866 fprintf (stderr, " Experimental options:\n");
4867 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4868 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);
4869 fprintf (stderr, "\n");
4871 usage_printed = TRUE;
4876 if (major_collector.is_concurrent)
4877 sgen_workers_init (1);
4879 if (major_collector_opt)
4880 g_free (major_collector_opt);
4882 if (minor_collector_opt)
4883 g_free (minor_collector_opt);
4887 sgen_cement_init (cement_enabled);
4889 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4890 gboolean usage_printed = FALSE;
4892 opts = g_strsplit (env, ",", -1);
4893 for (ptr = opts; ptr && *ptr; ptr ++) {
4895 if (!strcmp (opt, ""))
4897 if (opt [0] >= '0' && opt [0] <= '9') {
4898 gc_debug_level = atoi (opt);
4903 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4904 gc_debug_file = fopen (rf, "wb");
4906 gc_debug_file = stderr;
4909 } else if (!strcmp (opt, "print-allowance")) {
4910 debug_print_allowance = TRUE;
4911 } else if (!strcmp (opt, "print-pinning")) {
4912 do_pin_stats = TRUE;
4913 } else if (!strcmp (opt, "verify-before-allocs")) {
4914 verify_before_allocs = 1;
4915 has_per_allocation_action = TRUE;
4916 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4917 char *arg = strchr (opt, '=') + 1;
4918 verify_before_allocs = atoi (arg);
4919 has_per_allocation_action = TRUE;
4920 } else if (!strcmp (opt, "collect-before-allocs")) {
4921 collect_before_allocs = 1;
4922 has_per_allocation_action = TRUE;
4923 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4924 char *arg = strchr (opt, '=') + 1;
4925 has_per_allocation_action = TRUE;
4926 collect_before_allocs = atoi (arg);
4927 } else if (!strcmp (opt, "verify-before-collections")) {
4928 whole_heap_check_before_collection = TRUE;
4929 } else if (!strcmp (opt, "check-at-minor-collections")) {
4930 consistency_check_at_minor_collection = TRUE;
4931 nursery_clear_policy = CLEAR_AT_GC;
4932 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4933 if (!major_collector.is_concurrent) {
4934 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4937 mod_union_consistency_check = TRUE;
4938 } else if (!strcmp (opt, "check-mark-bits")) {
4939 check_mark_bits_after_major_collection = TRUE;
4940 } else if (!strcmp (opt, "check-nursery-pinned")) {
4941 check_nursery_objects_pinned = TRUE;
4942 } else if (!strcmp (opt, "xdomain-checks")) {
4943 xdomain_checks = TRUE;
4944 } else if (!strcmp (opt, "clear-at-gc")) {
4945 nursery_clear_policy = CLEAR_AT_GC;
4946 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4947 nursery_clear_policy = CLEAR_AT_GC;
4948 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4949 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4950 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4951 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4952 } else if (!strcmp (opt, "check-scan-starts")) {
4953 do_scan_starts_check = TRUE;
4954 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4955 do_verify_nursery = TRUE;
4956 } else if (!strcmp (opt, "check-concurrent")) {
4957 if (!major_collector.is_concurrent) {
4958 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4961 do_concurrent_checks = TRUE;
4962 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4963 do_dump_nursery_content = TRUE;
4964 } else if (!strcmp (opt, "no-managed-allocator")) {
4965 sgen_set_use_managed_allocator (FALSE);
4966 } else if (!strcmp (opt, "disable-minor")) {
4967 disable_minor_collections = TRUE;
4968 } else if (!strcmp (opt, "disable-major")) {
4969 disable_major_collections = TRUE;
4970 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4971 char *filename = strchr (opt, '=') + 1;
4972 nursery_clear_policy = CLEAR_AT_GC;
4973 heap_dump_file = fopen (filename, "w");
4974 if (heap_dump_file) {
4975 fprintf (heap_dump_file, "<sgen-dump>\n");
4976 do_pin_stats = TRUE;
4978 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4979 char *filename = strchr (opt, '=') + 1;
4980 char *colon = strrchr (filename, ':');
4983 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
4984 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
4989 binary_protocol_init (filename, (long long)limit);
4990 } else if (!strcmp (opt, "nursery-canaries")) {
4991 do_verify_nursery = TRUE;
4992 sgen_set_use_managed_allocator (FALSE);
4993 enable_nursery_canaries = TRUE;
4994 } else if (!sgen_bridge_handle_gc_debug (opt)) {
4995 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5000 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);
5001 fprintf (stderr, "Valid <option>s are:\n");
5002 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5003 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5004 fprintf (stderr, " check-at-minor-collections\n");
5005 fprintf (stderr, " check-mark-bits\n");
5006 fprintf (stderr, " check-nursery-pinned\n");
5007 fprintf (stderr, " verify-before-collections\n");
5008 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5009 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5010 fprintf (stderr, " disable-minor\n");
5011 fprintf (stderr, " disable-major\n");
5012 fprintf (stderr, " xdomain-checks\n");
5013 fprintf (stderr, " check-concurrent\n");
5014 fprintf (stderr, " clear-[nursery-]at-gc\n");
5015 fprintf (stderr, " clear-at-tlab-creation\n");
5016 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5017 fprintf (stderr, " check-scan-starts\n");
5018 fprintf (stderr, " no-managed-allocator\n");
5019 fprintf (stderr, " print-allowance\n");
5020 fprintf (stderr, " print-pinning\n");
5021 fprintf (stderr, " heap-dump=<filename>\n");
5022 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5023 fprintf (stderr, " nursery-canaries\n");
5024 sgen_bridge_print_gc_debug_usage ();
5025 fprintf (stderr, "\n");
5027 usage_printed = TRUE;
5033 if (major_collector.post_param_init)
5034 major_collector.post_param_init (&major_collector);
5036 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5038 memset (&remset, 0, sizeof (remset));
5040 sgen_card_table_init (&remset);
5046 mono_gc_get_gc_name (void)
5051 static MonoMethod *write_barrier_method;
5054 sgen_is_critical_method (MonoMethod *method)
5056 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5060 sgen_has_critical_method (void)
5062 return write_barrier_method || sgen_has_managed_allocator ();
5068 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5070 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5071 #ifdef SGEN_ALIGN_NURSERY
5072 // if (ptr_in_nursery (ptr)) return;
5074 * Masking out the bits might be faster, but we would have to use 64 bit
5075 * immediates, which might be slower.
5077 mono_mb_emit_ldarg (mb, 0);
5078 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5079 mono_mb_emit_byte (mb, CEE_SHR_UN);
5080 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5081 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5083 if (!major_collector.is_concurrent) {
5084 // if (!ptr_in_nursery (*ptr)) return;
5085 mono_mb_emit_ldarg (mb, 0);
5086 mono_mb_emit_byte (mb, CEE_LDIND_I);
5087 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5088 mono_mb_emit_byte (mb, CEE_SHR_UN);
5089 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5090 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5093 int label_continue1, label_continue2;
5094 int dereferenced_var;
5096 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5097 mono_mb_emit_ldarg (mb, 0);
5098 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5099 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5101 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5102 mono_mb_emit_ldarg (mb, 0);
5103 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5104 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5107 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5110 mono_mb_patch_branch (mb, label_continue_1);
5111 mono_mb_patch_branch (mb, label_continue_2);
5113 // Dereference and store in local var
5114 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5115 mono_mb_emit_ldarg (mb, 0);
5116 mono_mb_emit_byte (mb, CEE_LDIND_I);
5117 mono_mb_emit_stloc (mb, dereferenced_var);
5119 if (!major_collector.is_concurrent) {
5120 // if (*ptr < sgen_get_nursery_start ()) return;
5121 mono_mb_emit_ldloc (mb, dereferenced_var);
5122 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5123 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5125 // if (*ptr >= sgen_get_nursery_end ()) return;
5126 mono_mb_emit_ldloc (mb, dereferenced_var);
5127 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5128 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5135 mono_gc_get_write_barrier (void)
5138 MonoMethodBuilder *mb;
5139 MonoMethodSignature *sig;
5140 #ifdef MANAGED_WBARRIER
5141 int i, nursery_check_labels [3];
5143 #ifdef HAVE_KW_THREAD
5144 int stack_end_offset = -1;
5146 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5147 g_assert (stack_end_offset != -1);
5151 // FIXME: Maybe create a separate version for ctors (the branch would be
5152 // correctly predicted more times)
5153 if (write_barrier_method)
5154 return write_barrier_method;
5156 /* Create the IL version of mono_gc_barrier_generic_store () */
5157 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5158 sig->ret = &mono_defaults.void_class->byval_arg;
5159 sig->params [0] = &mono_defaults.int_class->byval_arg;
5161 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5164 #ifdef MANAGED_WBARRIER
5165 emit_nursery_check (mb, nursery_check_labels);
5167 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5171 LDC_PTR sgen_cardtable
5173 address >> CARD_BITS
5177 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5178 LDC_PTR card_table_mask
5185 mono_mb_emit_ptr (mb, sgen_cardtable);
5186 mono_mb_emit_ldarg (mb, 0);
5187 mono_mb_emit_icon (mb, CARD_BITS);
5188 mono_mb_emit_byte (mb, CEE_SHR_UN);
5189 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5190 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5191 mono_mb_emit_byte (mb, CEE_AND);
5193 mono_mb_emit_byte (mb, CEE_ADD);
5194 mono_mb_emit_icon (mb, 1);
5195 mono_mb_emit_byte (mb, CEE_STIND_I1);
5198 for (i = 0; i < 3; ++i) {
5199 if (nursery_check_labels [i])
5200 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5202 mono_mb_emit_byte (mb, CEE_RET);
5204 mono_mb_emit_ldarg (mb, 0);
5205 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5206 mono_mb_emit_byte (mb, CEE_RET);
5209 res = mono_mb_create_method (mb, sig, 16);
5213 if (write_barrier_method) {
5214 /* Already created */
5215 mono_free_method (res);
5217 /* double-checked locking */
5218 mono_memory_barrier ();
5219 write_barrier_method = res;
5223 return write_barrier_method;
5227 mono_gc_get_description (void)
5229 return g_strdup ("sgen");
5233 mono_gc_set_desktop_mode (void)
5238 mono_gc_is_moving (void)
5244 mono_gc_is_disabled (void)
5250 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5257 sgen_get_nursery_clear_policy (void)
5259 return nursery_clear_policy;
5263 sgen_get_array_fill_vtable (void)
5265 if (!array_fill_vtable) {
5266 static MonoClass klass;
5267 static MonoVTable vtable;
5270 MonoDomain *domain = mono_get_root_domain ();
5273 klass.element_class = mono_defaults.byte_class;
5275 klass.instance_size = sizeof (MonoArray);
5276 klass.sizes.element_size = 1;
5277 klass.name = "array_filler_type";
5279 vtable.klass = &klass;
5281 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5284 array_fill_vtable = &vtable;
5286 return array_fill_vtable;
5296 sgen_gc_unlock (void)
5298 gboolean try_free = sgen_try_free_some_memory;
5299 sgen_try_free_some_memory = FALSE;
5300 mono_mutex_unlock (&gc_mutex);
5301 MONO_GC_UNLOCKED ();
5303 mono_thread_hazardous_try_free_some ();
5307 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5309 major_collector.iterate_live_block_ranges (callback);
5313 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5315 major_collector.scan_card_table (FALSE, queue);
5319 sgen_get_major_collector (void)
5321 return &major_collector;
5324 void mono_gc_set_skip_thread (gboolean skip)
5326 SgenThreadInfo *info = mono_thread_info_current ();
5329 info->gc_disabled = skip;
5334 sgen_get_remset (void)
5340 mono_gc_get_vtable_bits (MonoClass *class)
5343 /* FIXME move this to the bridge code */
5344 if (sgen_need_bridge_processing ()) {
5345 switch (sgen_bridge_class_kind (class)) {
5346 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5347 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5348 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5350 case GC_BRIDGE_OPAQUE_CLASS:
5351 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5355 if (fin_callbacks.is_class_finalization_aware) {
5356 if (fin_callbacks.is_class_finalization_aware (class))
5357 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5363 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5370 sgen_check_whole_heap_stw (void)
5372 sgen_stop_world (0);
5373 sgen_clear_nursery_fragments ();
5374 sgen_check_whole_heap (FALSE);
5375 sgen_restart_world (0, NULL);
5379 sgen_gc_event_moves (void)
5381 if (moved_objects_idx) {
5382 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5383 moved_objects_idx = 0;
5388 sgen_timestamp (void)
5390 SGEN_TV_DECLARE (timestamp);
5391 SGEN_TV_GETTIME (timestamp);
5392 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5396 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5398 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5399 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5401 fin_callbacks = *callbacks;
5408 #endif /* HAVE_SGEN_GC */