2 * sgen-gc.c: Simple generational GC.
5 * Paolo Molaro (lupus@ximian.com)
6 * Rodrigo Kumpera (kumpera@gmail.com)
8 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
9 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
11 * Thread start/stop adapted from Boehm's GC:
12 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
13 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
14 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
15 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
16 * Copyright 2001-2003 Ximian, Inc
17 * Copyright 2003-2010 Novell, Inc.
18 * Copyright 2011 Xamarin, Inc.
19 * Copyright (C) 2012 Xamarin Inc
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Library General Public
23 * License 2.0 as published by the Free Software Foundation;
25 * This library is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
28 * Library General Public License for more details.
30 * You should have received a copy of the GNU Library General Public
31 * License 2.0 along with this library; if not, write to the Free
32 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
34 * Important: allocation provides always zeroed memory, having to do
35 * a memset after allocation is deadly for performance.
36 * Memory usage at startup is currently as follows:
38 * 64 KB internal space
40 * We should provide a small memory config with half the sizes
42 * We currently try to make as few mono assumptions as possible:
43 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
45 * 2) gc descriptor is the second word in the vtable (first word in the class)
46 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
47 * 4) there is a function to get an object's size and the number of
48 * elements in an array.
49 * 5) we know the special way bounds are allocated for complex arrays
50 * 6) we know about proxies and how to treat them when domains are unloaded
52 * Always try to keep stack usage to a minimum: no recursive behaviour
53 * and no large stack allocs.
55 * General description.
56 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
57 * When the nursery is full we start a nursery collection: this is performed with a
59 * When the old generation is full we start a copying GC of the old generation as well:
60 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
61 * in the future. Maybe we'll even do both during the same collection like IMMIX.
63 * The things that complicate this description are:
64 * *) pinned objects: we can't move them so we need to keep track of them
65 * *) no precise info of the thread stacks and registers: we need to be able to
66 * quickly find the objects that may be referenced conservatively and pin them
67 * (this makes the first issues more important)
68 * *) large objects are too expensive to be dealt with using copying GC: we handle them
69 * with mark/sweep during major collections
70 * *) some objects need to not move even if they are small (interned strings, Type handles):
71 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
72 * PinnedChunks regions
78 *) we could have a function pointer in MonoClass to implement
79 customized write barriers for value types
81 *) investigate the stuff needed to advance a thread to a GC-safe
82 point (single-stepping, read from unmapped memory etc) and implement it.
83 This would enable us to inline allocations and write barriers, for example,
84 or at least parts of them, like the write barrier checks.
85 We may need this also for handling precise info on stacks, even simple things
86 as having uninitialized data on the stack and having to wait for the prolog
87 to zero it. Not an issue for the last frame that we scan conservatively.
88 We could always not trust the value in the slots anyway.
90 *) modify the jit to save info about references in stack locations:
91 this can be done just for locals as a start, so that at least
92 part of the stack is handled precisely.
94 *) test/fix endianess issues
96 *) Implement a card table as the write barrier instead of remembered
97 sets? Card tables are not easy to implement with our current
98 memory layout. We have several different kinds of major heap
99 objects: Small objects in regular blocks, small objects in pinned
100 chunks and LOS objects. If we just have a pointer we have no way
101 to tell which kind of object it points into, therefore we cannot
102 know where its card table is. The least we have to do to make
103 this happen is to get rid of write barriers for indirect stores.
106 *) Get rid of write barriers for indirect stores. We can do this by
107 telling the GC to wbarrier-register an object once we do an ldloca
108 or ldelema on it, and to unregister it once it's not used anymore
109 (it can only travel downwards on the stack). The problem with
110 unregistering is that it needs to happen eventually no matter
111 what, even if exceptions are thrown, the thread aborts, etc.
112 Rodrigo suggested that we could do only the registering part and
113 let the collector find out (pessimistically) when it's safe to
114 unregister, namely when the stack pointer of the thread that
115 registered the object is higher than it was when the registering
116 happened. This might make for a good first implementation to get
117 some data on performance.
119 *) Some sort of blacklist support? Blacklists is a concept from the
120 Boehm GC: if during a conservative scan we find pointers to an
121 area which we might use as heap, we mark that area as unusable, so
122 pointer retention by random pinning pointers is reduced.
124 *) experiment with max small object size (very small right now - 2kb,
125 because it's tied to the max freelist size)
127 *) add an option to mmap the whole heap in one chunk: it makes for many
128 simplifications in the checks (put the nursery at the top and just use a single
129 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
130 not flexible (too much of the address space may be used by default or we can't
131 increase the heap as needed) and we'd need a race-free mechanism to return memory
132 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
133 was written to, munmap is needed, but the following mmap may not find the same segment
136 *) memzero the major fragments after restarting the world and optionally a smaller
139 *) investigate having fragment zeroing threads
141 *) separate locks for finalization and other minor stuff to reduce
144 *) try a different copying order to improve memory locality
146 *) a thread abort after a store but before the write barrier will
147 prevent the write barrier from executing
149 *) specialized dynamically generated markers/copiers
151 *) Dynamically adjust TLAB size to the number of threads. If we have
152 too many threads that do allocation, we might need smaller TLABs,
153 and we might get better performance with larger TLABs if we only
154 have a handful of threads. We could sum up the space left in all
155 assigned TLABs and if that's more than some percentage of the
156 nursery size, reduce the TLAB size.
158 *) Explore placing unreachable objects on unused nursery memory.
159 Instead of memset'ng a region to zero, place an int[] covering it.
160 A good place to start is add_nursery_frag. The tricky thing here is
161 placing those objects atomically outside of a collection.
163 *) Allocation should use asymmetric Dekker synchronization:
164 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
165 This should help weak consistency archs.
172 #define _XOPEN_SOURCE
173 #define _DARWIN_C_SOURCE
179 #ifdef HAVE_PTHREAD_H
182 #ifdef HAVE_PTHREAD_NP_H
183 #include <pthread_np.h>
185 #ifdef HAVE_SEMAPHORE_H
186 #include <semaphore.h>
194 #include "metadata/sgen-gc.h"
195 #include "metadata/metadata-internals.h"
196 #include "metadata/class-internals.h"
197 #include "metadata/gc-internal.h"
198 #include "metadata/object-internals.h"
199 #include "metadata/threads.h"
200 #include "metadata/sgen-cardtable.h"
201 #include "metadata/sgen-protocol.h"
202 #include "metadata/sgen-archdep.h"
203 #include "metadata/sgen-bridge.h"
204 #include "metadata/sgen-memory-governor.h"
205 #include "metadata/sgen-hash-table.h"
206 #include "metadata/mono-gc.h"
207 #include "metadata/method-builder.h"
208 #include "metadata/profiler-private.h"
209 #include "metadata/monitor.h"
210 #include "metadata/mempool-internals.h"
211 #include "metadata/marshal.h"
212 #include "metadata/runtime.h"
213 #include "metadata/sgen-cardtable.h"
214 #include "metadata/sgen-pinning.h"
215 #include "metadata/sgen-workers.h"
216 #include "metadata/sgen-layout-stats.h"
217 #include "utils/mono-mmap.h"
218 #include "utils/mono-time.h"
219 #include "utils/mono-semaphore.h"
220 #include "utils/mono-counters.h"
221 #include "utils/mono-proclib.h"
222 #include "utils/mono-memory-model.h"
223 #include "utils/mono-logger-internal.h"
224 #include "utils/dtrace.h"
226 #include <mono/utils/mono-logger-internal.h>
227 #include <mono/utils/memcheck.h>
229 #if defined(__MACH__)
230 #include "utils/mach-support.h"
233 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
237 #include "mono/cil/opcode.def"
243 #undef pthread_create
245 #undef pthread_detach
248 * ######################################################################
249 * ######## Types and constants used by the GC.
250 * ######################################################################
253 /* 0 means not initialized, 1 is initialized, -1 means in progress */
254 static int gc_initialized = 0;
255 /* If set, check if we need to do something every X allocations */
256 gboolean has_per_allocation_action;
257 /* If set, do a heap check every X allocation */
258 guint32 verify_before_allocs = 0;
259 /* If set, do a minor collection before every X allocation */
260 guint32 collect_before_allocs = 0;
261 /* If set, do a whole heap check before each collection */
262 static gboolean whole_heap_check_before_collection = FALSE;
263 /* If set, do a heap consistency check before each minor collection */
264 static gboolean consistency_check_at_minor_collection = FALSE;
265 /* If set, do a mod union consistency check before each finishing collection pause */
266 static gboolean mod_union_consistency_check = FALSE;
267 /* If set, check whether mark bits are consistent after major collections */
268 static gboolean check_mark_bits_after_major_collection = FALSE;
269 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
270 static gboolean check_nursery_objects_pinned = FALSE;
271 /* If set, do a few checks when the concurrent collector is used */
272 static gboolean do_concurrent_checks = FALSE;
273 /* If set, check that there are no references to the domain left at domain unload */
274 static gboolean xdomain_checks = FALSE;
275 /* If not null, dump the heap after each collection into this file */
276 static FILE *heap_dump_file = NULL;
277 /* If set, mark stacks conservatively, even if precise marking is possible */
278 static gboolean conservative_stack_mark = FALSE;
279 /* If set, do a plausibility check on the scan_starts before and after
281 static gboolean do_scan_starts_check = FALSE;
283 * If the major collector is concurrent and this is FALSE, we will
284 * never initiate a synchronous major collection, unless requested via
287 static gboolean allow_synchronous_major = TRUE;
288 static gboolean disable_minor_collections = FALSE;
289 static gboolean disable_major_collections = FALSE;
290 gboolean do_pin_stats = FALSE;
291 static gboolean do_verify_nursery = FALSE;
292 static gboolean do_dump_nursery_content = FALSE;
293 static gboolean enable_nursery_canaries = FALSE;
295 #ifdef HEAVY_STATISTICS
296 long long stat_objects_alloced_degraded = 0;
297 long long stat_bytes_alloced_degraded = 0;
299 long long stat_copy_object_called_nursery = 0;
300 long long stat_objects_copied_nursery = 0;
301 long long stat_copy_object_called_major = 0;
302 long long stat_objects_copied_major = 0;
304 long long stat_scan_object_called_nursery = 0;
305 long long stat_scan_object_called_major = 0;
307 long long stat_slots_allocated_in_vain;
309 long long stat_nursery_copy_object_failed_from_space = 0;
310 long long stat_nursery_copy_object_failed_forwarded = 0;
311 long long stat_nursery_copy_object_failed_pinned = 0;
312 long long stat_nursery_copy_object_failed_to_space = 0;
314 static int stat_wbarrier_add_to_global_remset = 0;
315 static int stat_wbarrier_set_field = 0;
316 static int stat_wbarrier_set_arrayref = 0;
317 static int stat_wbarrier_arrayref_copy = 0;
318 static int stat_wbarrier_generic_store = 0;
319 static int stat_wbarrier_generic_store_atomic = 0;
320 static int stat_wbarrier_set_root = 0;
321 static int stat_wbarrier_value_copy = 0;
322 static int stat_wbarrier_object_copy = 0;
325 static long long stat_pinned_objects = 0;
327 static long long time_minor_pre_collection_fragment_clear = 0;
328 static long long time_minor_pinning = 0;
329 static long long time_minor_scan_remsets = 0;
330 static long long time_minor_scan_pinned = 0;
331 static long long time_minor_scan_registered_roots = 0;
332 static long long time_minor_scan_thread_data = 0;
333 static long long time_minor_finish_gray_stack = 0;
334 static long long time_minor_fragment_creation = 0;
336 static long long time_major_pre_collection_fragment_clear = 0;
337 static long long time_major_pinning = 0;
338 static long long time_major_scan_pinned = 0;
339 static long long time_major_scan_registered_roots = 0;
340 static long long time_major_scan_thread_data = 0;
341 static long long time_major_scan_alloc_pinned = 0;
342 static long long time_major_scan_finalized = 0;
343 static long long time_major_scan_big_objects = 0;
344 static long long time_major_finish_gray_stack = 0;
345 static long long time_major_free_bigobjs = 0;
346 static long long time_major_los_sweep = 0;
347 static long long time_major_sweep = 0;
348 static long long time_major_fragment_creation = 0;
350 static long long time_max = 0;
352 static SGEN_TV_DECLARE (time_major_conc_collection_start);
353 static SGEN_TV_DECLARE (time_major_conc_collection_end);
355 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
356 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
358 int gc_debug_level = 0;
361 static MonoGCFinalizerCallbacks fin_callbacks;
365 mono_gc_flush_info (void)
367 fflush (gc_debug_file);
371 #define TV_DECLARE SGEN_TV_DECLARE
372 #define TV_GETTIME SGEN_TV_GETTIME
373 #define TV_ELAPSED SGEN_TV_ELAPSED
374 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
376 SGEN_TV_DECLARE (sgen_init_timestamp);
378 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
380 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
382 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
383 #define object_is_pinned SGEN_OBJECT_IS_PINNED
384 #define pin_object SGEN_PIN_OBJECT
385 #define unpin_object SGEN_UNPIN_OBJECT
387 #define ptr_in_nursery sgen_ptr_in_nursery
389 #define LOAD_VTABLE SGEN_LOAD_VTABLE
392 safe_name (void* obj)
394 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
395 return vt->klass->name;
399 nursery_canaries_enabled (void)
401 return enable_nursery_canaries;
404 #define safe_object_get_size sgen_safe_object_get_size
407 sgen_safe_name (void* obj)
409 return safe_name (obj);
413 * ######################################################################
414 * ######## Global data.
415 * ######################################################################
417 LOCK_DECLARE (gc_mutex);
418 gboolean sgen_try_free_some_memory;
420 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
422 static mword pagesize = 4096;
423 size_t degraded_mode = 0;
425 static mword bytes_pinned_from_failed_allocation = 0;
427 GCMemSection *nursery_section = NULL;
428 static volatile mword lowest_heap_address = ~(mword)0;
429 static volatile mword highest_heap_address = 0;
431 LOCK_DECLARE (sgen_interruption_mutex);
432 static LOCK_DECLARE (pin_queue_mutex);
434 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
435 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
437 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
438 struct _FinalizeReadyEntry {
439 FinalizeReadyEntry *next;
443 typedef struct _EphemeronLinkNode EphemeronLinkNode;
445 struct _EphemeronLinkNode {
446 EphemeronLinkNode *next;
455 int current_collection_generation = -1;
456 volatile gboolean concurrent_collection_in_progress = FALSE;
458 /* objects that are ready to be finalized */
459 static FinalizeReadyEntry *fin_ready_list = NULL;
460 static FinalizeReadyEntry *critical_fin_list = NULL;
462 static EphemeronLinkNode *ephemeron_list;
464 /* registered roots: the key to the hash is the root start address */
466 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
468 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
469 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
470 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
471 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
473 static mword roots_size = 0; /* amount of memory in the root set */
475 #define GC_ROOT_NUM 32
477 int count; /* must be the first field */
478 void *objects [GC_ROOT_NUM];
479 int root_types [GC_ROOT_NUM];
480 uintptr_t extra_info [GC_ROOT_NUM];
484 notify_gc_roots (GCRootReport *report)
488 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
493 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
495 if (report->count == GC_ROOT_NUM)
496 notify_gc_roots (report);
497 report->objects [report->count] = object;
498 report->root_types [report->count] = rtype;
499 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
502 MonoNativeTlsKey thread_info_key;
504 #ifdef HAVE_KW_THREAD
505 __thread SgenThreadInfo *sgen_thread_info;
506 __thread char *stack_end;
509 /* The size of a TLAB */
510 /* The bigger the value, the less often we have to go to the slow path to allocate a new
511 * one, but the more space is wasted by threads not allocating much memory.
513 * FIXME: Make this self-tuning for each thread.
515 guint32 tlab_size = (1024 * 4);
517 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
519 /* Functions supplied by the runtime to be called by the GC */
520 static MonoGCCallbacks gc_callbacks;
522 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
523 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
525 #define ALIGN_UP SGEN_ALIGN_UP
527 #define MOVED_OBJECTS_NUM 64
528 static void *moved_objects [MOVED_OBJECTS_NUM];
529 static int moved_objects_idx = 0;
531 /* Vtable of the objects used to fill out nursery fragments before a collection */
532 static MonoVTable *array_fill_vtable;
534 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
535 MonoNativeThreadId main_gc_thread = NULL;
538 /*Object was pinned during the current collection*/
539 static mword objects_pinned;
542 * ######################################################################
543 * ######## Macros and function declarations.
544 * ######################################################################
548 align_pointer (void *ptr)
550 mword p = (mword)ptr;
551 p += sizeof (gpointer) - 1;
552 p &= ~ (sizeof (gpointer) - 1);
556 typedef SgenGrayQueue GrayQueue;
558 /* forward declarations */
559 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
560 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
561 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
562 static void report_finalizer_roots (void);
563 static void report_registered_roots (void);
565 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
566 static void finish_gray_stack (int generation, GrayQueue *queue);
568 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
571 static void init_stats (void);
573 static int mark_ephemerons_in_range (ScanCopyContext ctx);
574 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
575 static void null_ephemerons_for_domain (MonoDomain *domain);
577 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
579 SgenObjectOperations current_object_ops;
580 SgenMajorCollector major_collector;
581 SgenMinorCollector sgen_minor_collector;
582 static GrayQueue gray_queue;
584 static SgenRemeberedSet remset;
586 /* The gray queue to use from the main collection thread. */
587 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
590 * The gray queue a worker job must use. If we're not parallel or
591 * concurrent, we use the main gray queue.
593 static SgenGrayQueue*
594 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
596 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
600 gray_queue_redirect (SgenGrayQueue *queue)
602 gboolean wake = FALSE;
605 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
608 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
613 g_assert (concurrent_collection_in_progress);
614 if (sgen_workers_have_started ()) {
615 sgen_workers_ensure_awake ();
617 if (concurrent_collection_in_progress)
618 g_assert (current_collection_generation == -1);
624 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
626 while (start < end) {
630 if (!*(void**)start) {
631 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
636 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
642 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
643 CHECK_CANARY_FOR_OBJECT (obj);
644 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
645 callback (obj, size, data);
646 CANARIFY_SIZE (size);
648 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
656 need_remove_object_for_domain (char *start, MonoDomain *domain)
658 if (mono_object_domain (start) == domain) {
659 SGEN_LOG (4, "Need to cleanup object %p", start);
660 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
667 process_object_for_domain_clearing (char *start, MonoDomain *domain)
669 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
670 if (vt->klass == mono_defaults.internal_thread_class)
671 g_assert (mono_object_domain (start) == mono_get_root_domain ());
672 /* The object could be a proxy for an object in the domain
674 #ifndef DISABLE_REMOTING
675 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
676 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
678 /* The server could already have been zeroed out, so
679 we need to check for that, too. */
680 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
681 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
682 ((MonoRealProxy*)start)->unwrapped_server = NULL;
689 clear_domain_process_object (char *obj, MonoDomain *domain)
693 process_object_for_domain_clearing (obj, domain);
694 remove = need_remove_object_for_domain (obj, domain);
696 if (remove && ((MonoObject*)obj)->synchronisation) {
697 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
699 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
706 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
708 if (clear_domain_process_object (obj, domain)) {
709 CANARIFY_SIZE (size);
710 memset (obj, 0, size);
715 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
717 clear_domain_process_object (obj, domain);
721 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
723 if (need_remove_object_for_domain (obj, domain))
724 major_collector.free_non_pinned_object (obj, size);
728 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
730 if (need_remove_object_for_domain (obj, domain))
731 major_collector.free_pinned_object (obj, size);
735 * When appdomains are unloaded we can easily remove objects that have finalizers,
736 * but all the others could still be present in random places on the heap.
737 * We need a sweep to get rid of them even though it's going to be costly
739 * The reason we need to remove them is because we access the vtable and class
740 * structures to know the object size and the reference bitmap: once the domain is
741 * unloaded the point to random memory.
744 mono_gc_clear_domain (MonoDomain * domain)
746 LOSObject *bigobj, *prev;
751 binary_protocol_domain_unload_begin (domain);
755 if (concurrent_collection_in_progress)
756 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
757 g_assert (!concurrent_collection_in_progress);
759 sgen_process_fin_stage_entries ();
760 sgen_process_dislink_stage_entries ();
762 sgen_clear_nursery_fragments ();
764 if (xdomain_checks && domain != mono_get_root_domain ()) {
765 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
766 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
767 sgen_check_for_xdomain_refs ();
770 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
771 to memory returned to the OS.*/
772 null_ephemerons_for_domain (domain);
774 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
775 sgen_null_links_for_domain (domain, i);
777 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
778 sgen_remove_finalizers_for_domain (domain, i);
780 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
781 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
783 /* We need two passes over major and large objects because
784 freeing such objects might give their memory back to the OS
785 (in the case of large objects) or obliterate its vtable
786 (pinned objects with major-copying or pinned and non-pinned
787 objects with major-mark&sweep), but we might need to
788 dereference a pointer from an object to another object if
789 the first object is a proxy. */
790 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
791 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
792 clear_domain_process_object (bigobj->data, domain);
795 for (bigobj = los_object_list; bigobj;) {
796 if (need_remove_object_for_domain (bigobj->data, domain)) {
797 LOSObject *to_free = bigobj;
799 prev->next = bigobj->next;
801 los_object_list = bigobj->next;
802 bigobj = bigobj->next;
803 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
804 sgen_los_free_object (to_free);
808 bigobj = bigobj->next;
810 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
811 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
813 if (domain == mono_get_root_domain ()) {
814 if (G_UNLIKELY (do_pin_stats))
815 sgen_pin_stats_print_class_stats ();
816 sgen_object_layout_dump (stdout);
819 sgen_restart_world (0, NULL);
821 binary_protocol_domain_unload_end (domain);
827 * sgen_add_to_global_remset:
829 * The global remset contains locations which point into newspace after
830 * a minor collection. This can happen if the objects they point to are pinned.
832 * LOCKING: If called from a parallel collector, the global remset
833 * lock must be held. For serial collectors that is not necessary.
836 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
838 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
840 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
842 if (!major_collector.is_concurrent) {
843 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
845 if (current_collection_generation == -1)
846 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
849 if (!object_is_pinned (obj))
850 SGEN_ASSERT (5, sgen_minor_collector.is_split || sgen_concurrent_collection_in_progress (), "Non-pinned objects can only remain in nursery if it is a split nursery");
851 else if (sgen_cement_lookup_or_register (obj))
854 remset.record_pointer (ptr);
856 if (G_UNLIKELY (do_pin_stats))
857 sgen_pin_stats_register_global_remset (obj);
859 SGEN_LOG (8, "Adding global remset for %p", ptr);
860 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
864 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
865 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
866 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
867 vt->klass->name_space, vt->klass->name);
873 * sgen_drain_gray_stack:
875 * Scan objects in the gray stack until the stack is empty. This should be called
876 * frequently after each object is copied, to achieve better locality and cache
879 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
883 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
885 ScanObjectFunc scan_func = ctx.scan_func;
886 GrayQueue *queue = ctx.queue;
890 for (i = 0; i != max_objs; ++i) {
893 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
896 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
897 scan_func (obj, desc, queue);
899 } while (max_objs < 0);
904 * Addresses in the pin queue are already sorted. This function finds
905 * the object header for each address and pins the object. The
906 * addresses must be inside the nursery section. The (start of the)
907 * address array is overwritten with the addresses of the actually
908 * pinned objects. Return the number of pinned objects.
911 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
913 GCMemSection *section = nursery_section;
914 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
915 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
916 void *start_nursery = section->data;
917 void *end_nursery = section->next_data;
922 void *pinning_front = start_nursery;
924 void **definitely_pinned = start;
925 ScanObjectFunc scan_func = ctx.scan_func;
926 SgenGrayQueue *queue = ctx.queue;
928 sgen_nursery_allocator_prepare_for_pinning ();
930 while (start < end) {
931 void *obj_to_pin = NULL;
932 size_t obj_to_pin_size = 0;
937 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
938 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
945 SGEN_LOG (5, "Considering pinning addr %p", addr);
946 /* We've already processed everything up to pinning_front. */
947 if (addr < pinning_front) {
953 * Find the closest scan start <= addr. We might search backward in the
954 * scan_starts array because entries might be NULL. In the worst case we
955 * start at start_nursery.
957 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
958 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
959 search_start = (void*)section->scan_starts [idx];
960 if (!search_start || search_start > addr) {
963 search_start = section->scan_starts [idx];
964 if (search_start && search_start <= addr)
967 if (!search_start || search_start > addr)
968 search_start = start_nursery;
972 * If the pinning front is closer than the scan start we found, start
973 * searching at the front.
975 if (search_start < pinning_front)
976 search_start = pinning_front;
979 * Now addr should be in an object a short distance from search_start.
981 * search_start must point to zeroed mem or point to an object.
987 if (!*(void**)search_start) {
988 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
989 /* The loop condition makes sure we don't overrun addr. */
993 obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
995 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
996 /* This is the object we're looking for. */
997 obj_to_pin = search_start;
998 obj_to_pin_size = obj_size;
1002 /* Skip to the next object */
1003 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
1004 CHECK_CANARY_FOR_OBJECT (search_start);
1005 CANARIFY_SIZE (obj_size);
1006 CANARIFY_SIZE (obj_to_pin_size);
1008 search_start = (void*)((char*)search_start + obj_size);
1009 } while (search_start <= addr);
1011 /* We've searched past the address we were looking for. */
1013 pinning_front = search_start;
1014 goto next_pin_queue_entry;
1018 * We've found an object to pin. It might still be a dummy array, but we
1019 * can advance the pinning front in any case.
1021 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1024 * If this is a dummy array marking the beginning of a nursery
1025 * fragment, we don't pin it.
1027 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1028 goto next_pin_queue_entry;
1031 * Finally - pin the object!
1033 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1035 scan_func (obj_to_pin, desc, queue);
1037 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1038 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1039 binary_protocol_pin (obj_to_pin,
1040 (gpointer)LOAD_VTABLE (obj_to_pin),
1041 safe_object_get_size (obj_to_pin));
1043 #ifdef ENABLE_DTRACE
1044 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1045 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1046 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1047 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1048 sgen_safe_object_get_size (obj_to_pin),
1049 vt->klass->name_space, vt->klass->name, gen);
1053 pin_object (obj_to_pin);
1054 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1055 if (G_UNLIKELY (do_pin_stats))
1056 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1057 definitely_pinned [count] = obj_to_pin;
1061 next_pin_queue_entry:
1065 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1066 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1067 GCRootReport report;
1069 for (idx = 0; idx < count; ++idx)
1070 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1071 notify_gc_roots (&report);
1073 stat_pinned_objects += count;
1078 pin_objects_in_nursery (ScanCopyContext ctx)
1082 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
1085 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1086 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
1091 sgen_pin_object (void *object, GrayQueue *queue)
1093 SGEN_PIN_OBJECT (object);
1094 sgen_pin_stage_ptr (object);
1096 if (G_UNLIKELY (do_pin_stats))
1097 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1099 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1100 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1102 #ifdef ENABLE_DTRACE
1103 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1104 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1105 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1106 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1112 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1116 gboolean major_pinned = FALSE;
1118 if (sgen_ptr_in_nursery (obj)) {
1119 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1120 sgen_pin_object (obj, queue);
1124 major_collector.pin_major_object (obj, queue);
1125 major_pinned = TRUE;
1128 vtable_word = *(mword*)obj;
1129 /*someone else forwarded it, update the pointer and bail out*/
1130 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1131 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1135 /*someone pinned it, nothing to do.*/
1136 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1141 /* Sort the addresses in array in increasing order.
1142 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1145 sgen_sort_addresses (void **array, size_t size)
1150 for (i = 1; i < size; ++i) {
1153 size_t parent = (child - 1) / 2;
1155 if (array [parent] >= array [child])
1158 tmp = array [parent];
1159 array [parent] = array [child];
1160 array [child] = tmp;
1166 for (i = size - 1; i > 0; --i) {
1169 array [i] = array [0];
1175 while (root * 2 + 1 <= end) {
1176 size_t child = root * 2 + 1;
1178 if (child < end && array [child] < array [child + 1])
1180 if (array [root] >= array [child])
1184 array [root] = array [child];
1185 array [child] = tmp;
1193 * Scan the memory between start and end and queue values which could be pointers
1194 * to the area between start_nursery and end_nursery for later consideration.
1195 * Typically used for thread stacks.
1198 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1202 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1203 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1206 while (start < end) {
1207 if (*start >= start_nursery && *start < end_nursery) {
1209 * *start can point to the middle of an object
1210 * note: should we handle pointing at the end of an object?
1211 * pinning in C# code disallows pointing at the end of an object
1212 * but there is some small chance that an optimizing C compiler
1213 * may keep the only reference to an object by pointing
1214 * at the end of it. We ignore this small chance for now.
1215 * Pointers to the end of an object are indistinguishable
1216 * from pointers to the start of the next object in memory
1217 * so if we allow that we'd need to pin two objects...
1218 * We queue the pointer in an array, the
1219 * array will then be sorted and uniqued. This way
1220 * we can coalesce several pinning pointers and it should
1221 * be faster since we'd do a memory scan with increasing
1222 * addresses. Note: we can align the address to the allocation
1223 * alignment, so the unique process is more effective.
1225 mword addr = (mword)*start;
1226 addr &= ~(ALLOC_ALIGN - 1);
1227 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1228 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1229 sgen_pin_stage_ptr ((void*)addr);
1230 binary_protocol_pin_stage (start, (void*)addr, thread_info);
1233 if (G_UNLIKELY (do_pin_stats)) {
1234 if (ptr_in_nursery ((void*)addr))
1235 sgen_pin_stats_register_address ((char*)addr, pin_type);
1241 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1245 * The first thing we do in a collection is to identify pinned objects.
1246 * This function considers all the areas of memory that need to be
1247 * conservatively scanned.
1250 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1254 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);
1255 /* objects pinned from the API are inside these roots */
1256 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1257 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1258 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1259 } SGEN_HASH_TABLE_FOREACH_END;
1260 /* now deal with the thread stacks
1261 * in the future we should be able to conservatively scan only:
1262 * *) the cpu registers
1263 * *) the unmanaged stack frames
1264 * *) the _last_ managed stack frame
1265 * *) pointers slots in managed frames
1267 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1271 unpin_objects_from_queue (SgenGrayQueue *queue)
1276 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1279 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1280 SGEN_UNPIN_OBJECT (addr);
1285 CopyOrMarkObjectFunc func;
1287 } UserCopyOrMarkData;
1290 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1292 UserCopyOrMarkData *data = gc_data;
1294 data->func (obj, data->queue);
1298 * The memory area from start_root to end_root contains pointers to objects.
1299 * Their position is precisely described by @desc (this means that the pointer
1300 * can be either NULL or the pointer to the start of an object).
1301 * This functions copies them to to_space updates them.
1303 * This function is not thread-safe!
1306 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1308 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1309 SgenGrayQueue *queue = ctx.queue;
1311 switch (desc & ROOT_DESC_TYPE_MASK) {
1312 case ROOT_DESC_BITMAP:
1313 desc >>= ROOT_DESC_TYPE_SHIFT;
1315 if ((desc & 1) && *start_root) {
1316 copy_func (start_root, queue);
1317 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1318 sgen_drain_gray_stack (-1, ctx);
1324 case ROOT_DESC_COMPLEX: {
1325 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1326 gsize bwords = (*bitmap_data) - 1;
1327 void **start_run = start_root;
1329 while (bwords-- > 0) {
1330 gsize bmap = *bitmap_data++;
1331 void **objptr = start_run;
1333 if ((bmap & 1) && *objptr) {
1334 copy_func (objptr, queue);
1335 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1336 sgen_drain_gray_stack (-1, ctx);
1341 start_run += GC_BITS_PER_WORD;
1345 case ROOT_DESC_USER: {
1346 UserCopyOrMarkData data = { copy_func, queue };
1347 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1348 marker (start_root, single_arg_user_copy_or_mark, &data);
1351 case ROOT_DESC_RUN_LEN:
1352 g_assert_not_reached ();
1354 g_assert_not_reached ();
1359 reset_heap_boundaries (void)
1361 lowest_heap_address = ~(mword)0;
1362 highest_heap_address = 0;
1366 sgen_update_heap_boundaries (mword low, mword high)
1371 old = lowest_heap_address;
1374 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1377 old = highest_heap_address;
1380 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1384 * Allocate and setup the data structures needed to be able to allocate objects
1385 * in the nursery. The nursery is stored in nursery_section.
1388 alloc_nursery (void)
1390 GCMemSection *section;
1395 if (nursery_section)
1397 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1398 /* later we will alloc a larger area for the nursery but only activate
1399 * what we need. The rest will be used as expansion if we have too many pinned
1400 * objects in the existing nursery.
1402 /* FIXME: handle OOM */
1403 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1405 alloc_size = sgen_nursery_size;
1407 /* If there isn't enough space even for the nursery we should simply abort. */
1408 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1410 #ifdef SGEN_ALIGN_NURSERY
1411 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1413 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1415 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1416 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 ());
1417 section->data = section->next_data = data;
1418 section->size = alloc_size;
1419 section->end_data = data + sgen_nursery_size;
1420 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1421 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1422 section->num_scan_start = scan_starts;
1424 nursery_section = section;
1426 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1430 mono_gc_get_nursery (int *shift_bits, size_t *size)
1432 *size = sgen_nursery_size;
1433 #ifdef SGEN_ALIGN_NURSERY
1434 *shift_bits = DEFAULT_NURSERY_BITS;
1438 return sgen_get_nursery_start ();
1442 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1444 SgenThreadInfo *info = mono_thread_info_current ();
1446 /* Could be called from sgen_thread_unregister () with a NULL info */
1449 info->stopped_domain = domain;
1454 mono_gc_precise_stack_mark_enabled (void)
1456 return !conservative_stack_mark;
1460 mono_gc_get_logfile (void)
1462 return gc_debug_file;
1466 report_finalizer_roots_list (FinalizeReadyEntry *list)
1468 GCRootReport report;
1469 FinalizeReadyEntry *fin;
1472 for (fin = list; fin; fin = fin->next) {
1475 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1477 notify_gc_roots (&report);
1481 report_finalizer_roots (void)
1483 report_finalizer_roots_list (fin_ready_list);
1484 report_finalizer_roots_list (critical_fin_list);
1487 static GCRootReport *root_report;
1490 single_arg_report_root (void **obj, void *gc_data)
1493 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1497 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1499 switch (desc & ROOT_DESC_TYPE_MASK) {
1500 case ROOT_DESC_BITMAP:
1501 desc >>= ROOT_DESC_TYPE_SHIFT;
1503 if ((desc & 1) && *start_root) {
1504 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1510 case ROOT_DESC_COMPLEX: {
1511 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1512 gsize bwords = (*bitmap_data) - 1;
1513 void **start_run = start_root;
1515 while (bwords-- > 0) {
1516 gsize bmap = *bitmap_data++;
1517 void **objptr = start_run;
1519 if ((bmap & 1) && *objptr) {
1520 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1525 start_run += GC_BITS_PER_WORD;
1529 case ROOT_DESC_USER: {
1530 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1531 root_report = report;
1532 marker (start_root, single_arg_report_root, NULL);
1535 case ROOT_DESC_RUN_LEN:
1536 g_assert_not_reached ();
1538 g_assert_not_reached ();
1543 report_registered_roots_by_type (int root_type)
1545 GCRootReport report;
1549 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1550 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1551 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1552 } SGEN_HASH_TABLE_FOREACH_END;
1553 notify_gc_roots (&report);
1557 report_registered_roots (void)
1559 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1560 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1564 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1566 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1567 SgenGrayQueue *queue = ctx.queue;
1568 FinalizeReadyEntry *fin;
1570 for (fin = list; fin; fin = fin->next) {
1573 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1574 copy_func (&fin->object, queue);
1579 generation_name (int generation)
1581 switch (generation) {
1582 case GENERATION_NURSERY: return "nursery";
1583 case GENERATION_OLD: return "old";
1584 default: g_assert_not_reached ();
1589 sgen_generation_name (int generation)
1591 return generation_name (generation);
1594 SgenObjectOperations *
1595 sgen_get_current_object_ops (void){
1596 return ¤t_object_ops;
1601 finish_gray_stack (int generation, GrayQueue *queue)
1605 int done_with_ephemerons, ephemeron_rounds = 0;
1606 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1607 ScanObjectFunc scan_func = current_object_ops.scan_object;
1608 ScanCopyContext ctx = { scan_func, copy_func, queue };
1609 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1610 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1613 * We copied all the reachable objects. Now it's the time to copy
1614 * the objects that were not referenced by the roots, but by the copied objects.
1615 * we built a stack of objects pointed to by gray_start: they are
1616 * additional roots and we may add more items as we go.
1617 * We loop until gray_start == gray_objects which means no more objects have
1618 * been added. Note this is iterative: no recursion is involved.
1619 * We need to walk the LO list as well in search of marked big objects
1620 * (use a flag since this is needed only on major collections). We need to loop
1621 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1622 * To achieve better cache locality and cache usage, we drain the gray stack
1623 * frequently, after each object is copied, and just finish the work here.
1625 sgen_drain_gray_stack (-1, ctx);
1627 SGEN_LOG (2, "%s generation done", generation_name (generation));
1630 Reset bridge data, we might have lingering data from a previous collection if this is a major
1631 collection trigged by minor overflow.
1633 We must reset the gathered bridges since their original block might be evacuated due to major
1634 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1636 if (sgen_need_bridge_processing ())
1637 sgen_bridge_reset_data ();
1640 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1641 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1642 * objects that are in fact reachable.
1644 done_with_ephemerons = 0;
1646 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1647 sgen_drain_gray_stack (-1, ctx);
1649 } while (!done_with_ephemerons);
1651 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1653 if (sgen_need_bridge_processing ()) {
1654 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1655 sgen_drain_gray_stack (-1, ctx);
1656 sgen_collect_bridge_objects (generation, ctx);
1657 if (generation == GENERATION_OLD)
1658 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1661 Do the first bridge step here, as the collector liveness state will become useless after that.
1663 An important optimization is to only proccess the possibly dead part of the object graph and skip
1664 over all live objects as we transitively know everything they point must be alive too.
1666 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1668 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1669 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1672 sgen_bridge_processing_stw_step ();
1676 Make sure we drain the gray stack before processing disappearing links and finalizers.
1677 If we don't make sure it is empty we might wrongly see a live object as dead.
1679 sgen_drain_gray_stack (-1, ctx);
1682 We must clear weak links that don't track resurrection before processing object ready for
1683 finalization so they can be cleared before that.
1685 sgen_null_link_in_range (generation, TRUE, ctx);
1686 if (generation == GENERATION_OLD)
1687 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1690 /* walk the finalization queue and move also the objects that need to be
1691 * finalized: use the finalized objects as new roots so the objects they depend
1692 * on are also not reclaimed. As with the roots above, only objects in the nursery
1693 * are marked/copied.
1695 sgen_finalize_in_range (generation, ctx);
1696 if (generation == GENERATION_OLD)
1697 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1698 /* drain the new stack that might have been created */
1699 SGEN_LOG (6, "Precise scan of gray area post fin");
1700 sgen_drain_gray_stack (-1, ctx);
1703 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1705 done_with_ephemerons = 0;
1707 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1708 sgen_drain_gray_stack (-1, ctx);
1710 } while (!done_with_ephemerons);
1713 * Clear ephemeron pairs with unreachable keys.
1714 * We pass the copy func so we can figure out if an array was promoted or not.
1716 clear_unreachable_ephemerons (ctx);
1719 * We clear togglerefs only after all possible chances of revival are done.
1720 * This is semantically more inline with what users expect and it allows for
1721 * user finalizers to correctly interact with TR objects.
1723 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1726 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1729 * handle disappearing links
1730 * Note we do this after checking the finalization queue because if an object
1731 * survives (at least long enough to be finalized) we don't clear the link.
1732 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1733 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1736 g_assert (sgen_gray_object_queue_is_empty (queue));
1738 sgen_null_link_in_range (generation, FALSE, ctx);
1739 if (generation == GENERATION_OLD)
1740 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1741 if (sgen_gray_object_queue_is_empty (queue))
1743 sgen_drain_gray_stack (-1, ctx);
1746 g_assert (sgen_gray_object_queue_is_empty (queue));
1748 sgen_gray_object_queue_trim_free_list (queue);
1752 sgen_check_section_scan_starts (GCMemSection *section)
1755 for (i = 0; i < section->num_scan_start; ++i) {
1756 if (section->scan_starts [i]) {
1757 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1758 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1764 check_scan_starts (void)
1766 if (!do_scan_starts_check)
1768 sgen_check_section_scan_starts (nursery_section);
1769 major_collector.check_scan_starts ();
1773 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1777 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1778 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1779 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1780 } SGEN_HASH_TABLE_FOREACH_END;
1784 sgen_dump_occupied (char *start, char *end, char *section_start)
1786 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1790 sgen_dump_section (GCMemSection *section, const char *type)
1792 char *start = section->data;
1793 char *end = section->data + section->size;
1794 char *occ_start = NULL;
1796 char *old_start = NULL; /* just for debugging */
1798 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1800 while (start < end) {
1804 if (!*(void**)start) {
1806 sgen_dump_occupied (occ_start, start, section->data);
1809 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1812 g_assert (start < section->next_data);
1817 vt = (GCVTable*)LOAD_VTABLE (start);
1820 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1823 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1824 start - section->data,
1825 vt->klass->name_space, vt->klass->name,
1833 sgen_dump_occupied (occ_start, start, section->data);
1835 fprintf (heap_dump_file, "</section>\n");
1839 dump_object (MonoObject *obj, gboolean dump_location)
1841 static char class_name [1024];
1843 MonoClass *class = mono_object_class (obj);
1847 * Python's XML parser is too stupid to parse angle brackets
1848 * in strings, so we just ignore them;
1851 while (class->name [i] && j < sizeof (class_name) - 1) {
1852 if (!strchr ("<>\"", class->name [i]))
1853 class_name [j++] = class->name [i];
1856 g_assert (j < sizeof (class_name));
1859 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1860 class->name_space, class_name,
1861 safe_object_get_size (obj));
1862 if (dump_location) {
1863 const char *location;
1864 if (ptr_in_nursery (obj))
1865 location = "nursery";
1866 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1870 fprintf (heap_dump_file, " location=\"%s\"", location);
1872 fprintf (heap_dump_file, "/>\n");
1876 dump_heap (const char *type, int num, const char *reason)
1881 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1883 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1884 fprintf (heap_dump_file, ">\n");
1885 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1886 sgen_dump_internal_mem_usage (heap_dump_file);
1887 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1888 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1889 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1891 fprintf (heap_dump_file, "<pinned-objects>\n");
1892 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1893 dump_object (list->obj, TRUE);
1894 fprintf (heap_dump_file, "</pinned-objects>\n");
1896 sgen_dump_section (nursery_section, "nursery");
1898 major_collector.dump_heap (heap_dump_file);
1900 fprintf (heap_dump_file, "<los>\n");
1901 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1902 dump_object ((MonoObject*)bigobj->data, FALSE);
1903 fprintf (heap_dump_file, "</los>\n");
1905 fprintf (heap_dump_file, "</collection>\n");
1909 sgen_register_moved_object (void *obj, void *destination)
1911 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1913 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1914 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1915 moved_objects_idx = 0;
1917 moved_objects [moved_objects_idx++] = obj;
1918 moved_objects [moved_objects_idx++] = destination;
1924 static gboolean inited = FALSE;
1929 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1931 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1932 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pinning);
1933 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1934 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1935 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1936 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1937 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1938 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1940 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1941 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pinning);
1942 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1943 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1944 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1945 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1946 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1947 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1948 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1949 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1950 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1951 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_sweep);
1952 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1954 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
1956 #ifdef HEAVY_STATISTICS
1957 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1958 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1959 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1960 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1961 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1962 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1963 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1964 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1965 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1967 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
1968 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
1970 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
1971 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
1972 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
1973 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
1975 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
1976 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
1978 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
1980 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
1981 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
1982 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
1983 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
1985 sgen_nursery_allocator_init_heavy_stats ();
1986 sgen_alloc_init_heavy_stats ();
1994 reset_pinned_from_failed_allocation (void)
1996 bytes_pinned_from_failed_allocation = 0;
2000 sgen_set_pinned_from_failed_allocation (mword objsize)
2002 bytes_pinned_from_failed_allocation += objsize;
2006 sgen_collection_is_concurrent (void)
2008 switch (current_collection_generation) {
2009 case GENERATION_NURSERY:
2011 case GENERATION_OLD:
2012 return concurrent_collection_in_progress;
2014 g_error ("Invalid current generation %d", current_collection_generation);
2019 sgen_concurrent_collection_in_progress (void)
2021 return concurrent_collection_in_progress;
2028 } FinishRememberedSetScanJobData;
2031 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2033 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2035 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2036 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2041 CopyOrMarkObjectFunc copy_or_mark_func;
2042 ScanObjectFunc scan_func;
2046 } ScanFromRegisteredRootsJobData;
2049 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2051 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2052 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2053 sgen_workers_get_job_gray_queue (worker_data) };
2055 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2056 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2063 } ScanThreadDataJobData;
2066 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2068 ScanThreadDataJobData *job_data = job_data_untyped;
2070 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2071 sgen_workers_get_job_gray_queue (worker_data));
2072 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2076 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2078 FinalizeReadyEntry *list = job_data_untyped;
2079 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2081 scan_finalizer_entries (list, ctx);
2085 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2087 g_assert (concurrent_collection_in_progress);
2088 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2092 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2094 g_assert (concurrent_collection_in_progress);
2095 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2099 verify_scan_starts (char *start, char *end)
2103 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2104 char *addr = nursery_section->scan_starts [i];
2105 if (addr > start && addr < end)
2106 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2111 verify_nursery (void)
2113 char *start, *end, *cur, *hole_start;
2115 if (!do_verify_nursery)
2118 if (nursery_canaries_enabled ())
2119 SGEN_LOG (1, "Checking nursery canaries...");
2121 /*This cleans up unused fragments */
2122 sgen_nursery_allocator_prepare_for_pinning ();
2124 hole_start = start = cur = sgen_get_nursery_start ();
2125 end = sgen_get_nursery_end ();
2130 if (!*(void**)cur) {
2131 cur += sizeof (void*);
2135 if (object_is_forwarded (cur))
2136 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2137 else if (object_is_pinned (cur))
2138 SGEN_LOG (1, "PINNED OBJ %p", cur);
2140 ss = safe_object_get_size ((MonoObject*)cur);
2141 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2142 verify_scan_starts (cur, cur + size);
2143 if (do_dump_nursery_content) {
2144 if (cur > hole_start)
2145 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2146 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 ());
2148 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2149 CHECK_CANARY_FOR_OBJECT (cur);
2150 CANARIFY_SIZE (size);
2158 * Checks that no objects in the nursery are fowarded or pinned. This
2159 * is a precondition to restarting the mutator while doing a
2160 * concurrent collection. Note that we don't clear fragments because
2161 * we depend on that having happened earlier.
2164 check_nursery_is_clean (void)
2166 char *start, *end, *cur;
2168 start = cur = sgen_get_nursery_start ();
2169 end = sgen_get_nursery_end ();
2174 if (!*(void**)cur) {
2175 cur += sizeof (void*);
2179 g_assert (!object_is_forwarded (cur));
2180 g_assert (!object_is_pinned (cur));
2182 ss = safe_object_get_size ((MonoObject*)cur);
2183 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2184 verify_scan_starts (cur, cur + size);
2191 init_gray_queue (void)
2193 if (sgen_collection_is_concurrent ()) {
2194 sgen_workers_init_distribute_gray_queue ();
2195 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2196 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2198 sgen_gray_object_queue_init (&gray_queue, NULL);
2203 * Perform a nursery collection.
2205 * Return whether any objects were late-pinned due to being out of memory.
2208 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2210 gboolean needs_major;
2211 size_t max_garbage_amount;
2213 FinishRememberedSetScanJobData *frssjd;
2214 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2215 ScanThreadDataJobData *stdjd;
2216 mword fragment_total;
2217 ScanCopyContext ctx;
2221 if (disable_minor_collections)
2224 TV_GETTIME (last_minor_collection_start_tv);
2225 atv = last_minor_collection_start_tv;
2227 MONO_GC_BEGIN (GENERATION_NURSERY);
2228 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2232 #ifndef DISABLE_PERFCOUNTERS
2233 mono_perfcounters->gc_collections0++;
2236 current_collection_generation = GENERATION_NURSERY;
2237 current_object_ops = sgen_minor_collector.serial_ops;
2239 reset_pinned_from_failed_allocation ();
2241 check_scan_starts ();
2243 sgen_nursery_alloc_prepare_for_minor ();
2247 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2248 /* FIXME: optimize later to use the higher address where an object can be present */
2249 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2251 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 ()));
2252 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2253 g_assert (nursery_section->size >= max_garbage_amount);
2255 /* world must be stopped already */
2257 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2259 if (xdomain_checks) {
2260 sgen_clear_nursery_fragments ();
2261 sgen_check_for_xdomain_refs ();
2264 nursery_section->next_data = nursery_next;
2266 major_collector.start_nursery_collection ();
2268 sgen_memgov_minor_collection_start ();
2272 gc_stats.minor_gc_count ++;
2274 if (whole_heap_check_before_collection) {
2275 sgen_clear_nursery_fragments ();
2276 sgen_check_whole_heap (finish_up_concurrent_mark);
2278 if (consistency_check_at_minor_collection)
2279 sgen_check_consistency ();
2281 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2283 sgen_process_fin_stage_entries ();
2284 sgen_process_dislink_stage_entries ();
2286 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2288 /* pin from pinned handles */
2289 sgen_init_pinning ();
2290 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2291 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2292 /* pin cemented objects */
2293 sgen_pin_cemented_objects ();
2294 /* identify pinned objects */
2295 sgen_optimize_pin_queue ();
2296 sgen_pinning_setup_section (nursery_section);
2297 ctx.scan_func = NULL;
2298 ctx.copy_func = NULL;
2299 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2300 pin_objects_in_nursery (ctx);
2301 sgen_pinning_trim_queue_to_section (nursery_section);
2304 time_minor_pinning += TV_ELAPSED (btv, atv);
2305 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2306 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2308 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2310 sgen_workers_start_all_workers ();
2312 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2313 frssjd->heap_start = sgen_get_nursery_start ();
2314 frssjd->heap_end = nursery_next;
2315 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2317 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2319 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2320 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2322 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2324 /* FIXME: why is this here? */
2325 ctx.scan_func = current_object_ops.scan_object;
2326 ctx.copy_func = NULL;
2327 ctx.queue = &gray_queue;
2328 sgen_drain_gray_stack (-1, ctx);
2330 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2331 report_registered_roots ();
2332 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2333 report_finalizer_roots ();
2335 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2337 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2339 /* registered roots, this includes static fields */
2340 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2341 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2342 scrrjd_normal->scan_func = current_object_ops.scan_object;
2343 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2344 scrrjd_normal->heap_end = nursery_next;
2345 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2346 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2348 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2349 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2350 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2351 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2352 scrrjd_wbarrier->heap_end = nursery_next;
2353 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2354 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2357 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2359 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2362 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2363 stdjd->heap_start = sgen_get_nursery_start ();
2364 stdjd->heap_end = nursery_next;
2365 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2368 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2371 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2373 g_assert (!sgen_collection_is_concurrent ());
2375 /* Scan the list of objects ready for finalization. If */
2376 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2377 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2379 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2381 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2383 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2384 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2386 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2389 * The (single-threaded) finalization code might have done
2390 * some copying/marking so we can only reset the GC thread's
2391 * worker data here instead of earlier when we joined the
2394 sgen_workers_reset_data ();
2396 if (objects_pinned) {
2397 sgen_optimize_pin_queue ();
2398 sgen_pinning_setup_section (nursery_section);
2401 /* walk the pin_queue, build up the fragment list of free memory, unmark
2402 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2405 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2406 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2407 if (!fragment_total)
2410 /* Clear TLABs for all threads */
2411 sgen_clear_tlabs ();
2413 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2415 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2416 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2418 if (consistency_check_at_minor_collection)
2419 sgen_check_major_refs ();
2421 major_collector.finish_nursery_collection ();
2423 TV_GETTIME (last_minor_collection_end_tv);
2424 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2427 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2429 /* prepare the pin queue for the next collection */
2430 sgen_finish_pinning ();
2431 if (fin_ready_list || critical_fin_list) {
2432 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2433 mono_gc_finalize_notify ();
2435 sgen_pin_stats_reset ();
2436 /* clear cemented hash */
2437 sgen_cement_clear_below_threshold ();
2439 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2441 remset.finish_minor_collection ();
2443 check_scan_starts ();
2445 binary_protocol_flush_buffers (FALSE);
2447 sgen_memgov_minor_collection_end ();
2449 /*objects are late pinned because of lack of memory, so a major is a good call*/
2450 needs_major = objects_pinned > 0;
2451 current_collection_generation = -1;
2454 MONO_GC_END (GENERATION_NURSERY);
2455 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY);
2457 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2458 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2460 if (concurrent_collection_in_progress)
2461 sgen_workers_signal_finish_nursery_collection ();
2467 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2470 * This is called on all objects in the nursery, including pinned ones, so we need
2471 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2473 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2477 scan_nursery_objects (ScanCopyContext ctx)
2479 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2480 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2484 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union, gboolean scan_whole_nursery)
2489 /* FIXME: only use these values for the precise scan
2490 * note that to_space pointers should be excluded anyway...
2492 char *heap_start = NULL;
2493 char *heap_end = (char*)-1;
2494 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2495 GCRootReport root_report = { 0 };
2496 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2497 ScanThreadDataJobData *stdjd;
2498 ScanCopyContext ctx;
2500 if (concurrent_collection_in_progress) {
2501 /*This cleans up unused fragments */
2502 sgen_nursery_allocator_prepare_for_pinning ();
2504 if (do_concurrent_checks)
2505 check_nursery_is_clean ();
2507 /* The concurrent collector doesn't touch the nursery. */
2508 sgen_nursery_alloc_prepare_for_major ();
2515 /* Pinning depends on this */
2516 sgen_clear_nursery_fragments ();
2518 if (whole_heap_check_before_collection)
2519 sgen_check_whole_heap (finish_up_concurrent_mark);
2522 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2524 if (!sgen_collection_is_concurrent ())
2525 nursery_section->next_data = sgen_get_nursery_end ();
2526 /* we should also coalesce scanning from sections close to each other
2527 * and deal with pointers outside of the sections later.
2531 *major_collector.have_swept = FALSE;
2533 if (xdomain_checks) {
2534 sgen_clear_nursery_fragments ();
2535 sgen_check_for_xdomain_refs ();
2538 if (!concurrent_collection_in_progress) {
2539 /* Remsets are not useful for a major collection */
2540 remset.prepare_for_major_collection ();
2543 sgen_process_fin_stage_entries ();
2544 sgen_process_dislink_stage_entries ();
2547 sgen_init_pinning ();
2548 SGEN_LOG (6, "Collecting pinned addresses");
2549 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2551 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2552 if (major_collector.is_concurrent) {
2554 * The concurrent major collector cannot evict
2555 * yet, so we need to pin cemented objects to
2556 * not break some asserts.
2558 * FIXME: We could evict now!
2560 sgen_pin_cemented_objects ();
2563 if (!concurrent_collection_in_progress)
2564 sgen_cement_reset ();
2567 sgen_optimize_pin_queue ();
2570 * The concurrent collector doesn't move objects, neither on
2571 * the major heap nor in the nursery, so we can mark even
2572 * before pinning has finished. For the non-concurrent
2573 * collector we start the workers after pinning.
2575 if (concurrent_collection_in_progress)
2576 sgen_workers_start_all_workers ();
2579 * pin_queue now contains all candidate pointers, sorted and
2580 * uniqued. We must do two passes now to figure out which
2581 * objects are pinned.
2583 * The first is to find within the pin_queue the area for each
2584 * section. This requires that the pin_queue be sorted. We
2585 * also process the LOS objects and pinned chunks here.
2587 * The second, destructive, pass is to reduce the section
2588 * areas to pointers to the actually pinned objects.
2590 SGEN_LOG (6, "Pinning from sections");
2591 /* first pass for the sections */
2592 sgen_find_section_pin_queue_start_end (nursery_section);
2593 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2594 /* identify possible pointers to the insize of large objects */
2595 SGEN_LOG (6, "Pinning from large objects");
2596 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2598 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2599 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2601 #ifdef ENABLE_DTRACE
2602 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2603 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2604 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2608 if (sgen_los_object_is_pinned (bigobj->data)) {
2609 g_assert (finish_up_concurrent_mark);
2612 sgen_los_pin_object (bigobj->data);
2613 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2614 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2615 if (G_UNLIKELY (do_pin_stats))
2616 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2617 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));
2620 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2624 notify_gc_roots (&root_report);
2625 /* second pass for the sections */
2626 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2627 ctx.copy_func = NULL;
2628 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2631 * Concurrent mark never follows references into the nursery. In the start and
2632 * finish pauses we must scan live nursery objects, though.
2634 * In the finish pause we do this conservatively by scanning all nursery objects.
2635 * Previously we would only scan pinned objects here. We assumed that all objects
2636 * that were pinned during the nursery collection immediately preceding this finish
2637 * mark would be pinned again here. Due to the way we get the stack end for the GC
2638 * thread, however, that's not necessarily the case: we scan part of the stack used
2639 * by the GC itself, which changes constantly, so pinning isn't entirely
2642 * The split nursery also complicates things because non-pinned objects can survive
2643 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2645 * In the future we shouldn't do a preceding nursery collection at all and instead
2646 * do the finish pause with promotion from the nursery.
2648 * A further complication arises when we have late-pinned objects from the preceding
2649 * nursery collection. Those are the result of being out of memory when trying to
2650 * evacuate objects. They won't be found from the roots, so we just scan the whole
2653 * Non-concurrent mark evacuates from the nursery, so it's
2654 * sufficient to just scan pinned nursery objects.
2656 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2657 scan_nursery_objects (ctx);
2659 pin_objects_in_nursery (ctx);
2660 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2661 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2664 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2665 if (old_next_pin_slot)
2666 *old_next_pin_slot = sgen_get_pinned_count ();
2669 time_major_pinning += TV_ELAPSED (atv, btv);
2670 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2671 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2673 major_collector.init_to_space ();
2675 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2676 main_gc_thread = mono_native_thread_self ();
2679 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2680 report_registered_roots ();
2682 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2684 /* registered roots, this includes static fields */
2685 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2686 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2687 scrrjd_normal->scan_func = current_object_ops.scan_object;
2688 scrrjd_normal->heap_start = heap_start;
2689 scrrjd_normal->heap_end = heap_end;
2690 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2691 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2693 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2694 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2695 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2696 scrrjd_wbarrier->heap_start = heap_start;
2697 scrrjd_wbarrier->heap_end = heap_end;
2698 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2699 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2702 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2705 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2706 stdjd->heap_start = heap_start;
2707 stdjd->heap_end = heap_end;
2708 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2711 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2714 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2716 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2717 report_finalizer_roots ();
2719 /* scan the list of objects ready for finalization */
2720 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2721 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2723 if (scan_mod_union) {
2724 g_assert (finish_up_concurrent_mark);
2726 /* Mod union card table */
2727 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2728 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2732 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2733 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2736 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2738 if (concurrent_collection_in_progress) {
2739 /* prepare the pin queue for the next collection */
2740 sgen_finish_pinning ();
2742 sgen_pin_stats_reset ();
2744 if (do_concurrent_checks)
2745 check_nursery_is_clean ();
2750 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2752 MONO_GC_BEGIN (GENERATION_OLD);
2753 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2755 current_collection_generation = GENERATION_OLD;
2756 #ifndef DISABLE_PERFCOUNTERS
2757 mono_perfcounters->gc_collections1++;
2760 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2763 g_assert (major_collector.is_concurrent);
2764 concurrent_collection_in_progress = TRUE;
2766 sgen_cement_concurrent_start ();
2768 current_object_ops = major_collector.major_concurrent_ops;
2770 current_object_ops = major_collector.major_ops;
2773 reset_pinned_from_failed_allocation ();
2775 sgen_memgov_major_collection_start ();
2777 //count_ref_nonref_objs ();
2778 //consistency_check ();
2780 check_scan_starts ();
2783 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2784 gc_stats.major_gc_count ++;
2786 if (major_collector.start_major_collection)
2787 major_collector.start_major_collection ();
2789 major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE, FALSE);
2793 wait_for_workers_to_finish (void)
2795 while (!sgen_workers_all_done ())
2802 if (concurrent_collection_in_progress) {
2803 gray_queue_redirect (&gray_queue);
2804 sgen_workers_join ();
2807 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2809 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2810 main_gc_thread = NULL;
2815 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union, gboolean scan_whole_nursery)
2817 LOSObject *bigobj, *prevbo;
2823 if (concurrent_collection_in_progress)
2826 if (concurrent_collection_in_progress) {
2827 current_object_ops = major_collector.major_concurrent_ops;
2829 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union, scan_whole_nursery);
2832 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2834 if (do_concurrent_checks)
2835 check_nursery_is_clean ();
2837 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2838 current_object_ops = major_collector.major_ops;
2842 * The workers have stopped so we need to finish gray queue
2843 * work that might result from finalization in the main GC
2844 * thread. Redirection must therefore be turned off.
2846 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2847 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2849 /* all the objects in the heap */
2850 finish_gray_stack (GENERATION_OLD, &gray_queue);
2852 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2854 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2857 * The (single-threaded) finalization code might have done
2858 * some copying/marking so we can only reset the GC thread's
2859 * worker data here instead of earlier when we joined the
2862 sgen_workers_reset_data ();
2864 if (objects_pinned) {
2865 g_assert (!concurrent_collection_in_progress);
2868 * This is slow, but we just OOM'd.
2870 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2871 * queue is laid out at this point.
2873 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2875 * We need to reestablish all pinned nursery objects in the pin queue
2876 * because they're needed for fragment creation. Unpinning happens by
2877 * walking the whole queue, so it's not necessary to reestablish where major
2878 * heap block pins are - all we care is that they're still in there
2881 sgen_optimize_pin_queue ();
2882 sgen_find_section_pin_queue_start_end (nursery_section);
2886 reset_heap_boundaries ();
2887 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2889 if (!concurrent_collection_in_progress) {
2890 /* walk the pin_queue, build up the fragment list of free memory, unmark
2891 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2894 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2897 /* prepare the pin queue for the next collection */
2898 sgen_finish_pinning ();
2900 /* Clear TLABs for all threads */
2901 sgen_clear_tlabs ();
2903 sgen_pin_stats_reset ();
2906 if (concurrent_collection_in_progress)
2907 sgen_cement_concurrent_finish ();
2908 sgen_cement_clear_below_threshold ();
2910 if (check_mark_bits_after_major_collection)
2911 sgen_check_heap_marked (concurrent_collection_in_progress);
2914 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2917 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2919 /* sweep the big objects list */
2921 for (bigobj = los_object_list; bigobj;) {
2922 g_assert (!object_is_pinned (bigobj->data));
2923 if (sgen_los_object_is_pinned (bigobj->data)) {
2924 sgen_los_unpin_object (bigobj->data);
2925 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2928 /* not referenced anywhere, so we can free it */
2930 prevbo->next = bigobj->next;
2932 los_object_list = bigobj->next;
2934 bigobj = bigobj->next;
2935 sgen_los_free_object (to_free);
2939 bigobj = bigobj->next;
2943 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2948 time_major_los_sweep += TV_ELAPSED (atv, btv);
2950 major_collector.sweep ();
2952 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2955 time_major_sweep += TV_ELAPSED (btv, atv);
2958 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2960 if (fin_ready_list || critical_fin_list) {
2961 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2962 mono_gc_finalize_notify ();
2965 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2967 sgen_memgov_major_collection_end ();
2968 current_collection_generation = -1;
2970 major_collector.finish_major_collection ();
2972 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2974 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2975 if (concurrent_collection_in_progress)
2976 concurrent_collection_in_progress = FALSE;
2978 check_scan_starts ();
2980 binary_protocol_flush_buffers (FALSE);
2982 //consistency_check ();
2984 MONO_GC_END (GENERATION_OLD);
2985 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD);
2989 major_do_collection (const char *reason)
2991 TV_DECLARE (time_start);
2992 TV_DECLARE (time_end);
2993 size_t old_next_pin_slot;
2995 if (disable_major_collections)
2998 if (major_collector.get_and_reset_num_major_objects_marked) {
2999 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3000 g_assert (!num_marked);
3003 /* world must be stopped already */
3004 TV_GETTIME (time_start);
3006 major_start_collection (FALSE, &old_next_pin_slot);
3007 major_finish_collection (reason, old_next_pin_slot, FALSE, FALSE);
3009 TV_GETTIME (time_end);
3010 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3012 /* FIXME: also report this to the user, preferably in gc-end. */
3013 if (major_collector.get_and_reset_num_major_objects_marked)
3014 major_collector.get_and_reset_num_major_objects_marked ();
3016 return bytes_pinned_from_failed_allocation > 0;
3020 major_start_concurrent_collection (const char *reason)
3022 TV_DECLARE (time_start);
3023 TV_DECLARE (time_end);
3024 long long num_objects_marked;
3026 if (disable_major_collections)
3029 TV_GETTIME (time_start);
3030 SGEN_TV_GETTIME (time_major_conc_collection_start);
3032 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3033 g_assert (num_objects_marked == 0);
3035 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3036 binary_protocol_concurrent_start ();
3038 // FIXME: store reason and pass it when finishing
3039 major_start_collection (TRUE, NULL);
3041 gray_queue_redirect (&gray_queue);
3042 sgen_workers_wait_for_jobs_finished ();
3044 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3045 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3047 TV_GETTIME (time_end);
3048 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3050 current_collection_generation = -1;
3054 major_update_or_finish_concurrent_collection (gboolean force_finish)
3056 TV_DECLARE (total_start);
3057 TV_DECLARE (total_end);
3058 gboolean late_pinned;
3059 SgenGrayQueue unpin_queue;
3060 memset (&unpin_queue, 0, sizeof (unpin_queue));
3062 TV_GETTIME (total_start);
3064 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3065 binary_protocol_concurrent_update_finish ();
3067 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3069 if (!force_finish && !sgen_workers_all_done ()) {
3070 sgen_workers_signal_start_nursery_collection_and_wait ();
3072 major_collector.update_cardtable_mod_union ();
3073 sgen_los_update_cardtable_mod_union ();
3075 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3077 TV_GETTIME (total_end);
3078 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3084 * The major collector can add global remsets which are processed in the finishing
3085 * nursery collection, below. That implies that the workers must have finished
3086 * marking before the nursery collection is allowed to run, otherwise we might miss
3089 wait_for_workers_to_finish ();
3091 SGEN_TV_GETTIME (time_major_conc_collection_end);
3092 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3094 major_collector.update_cardtable_mod_union ();
3095 sgen_los_update_cardtable_mod_union ();
3097 late_pinned = collect_nursery (&unpin_queue, TRUE);
3099 if (mod_union_consistency_check)
3100 sgen_check_mod_union_consistency ();
3102 current_collection_generation = GENERATION_OLD;
3103 major_finish_collection ("finishing", -1, TRUE, late_pinned);
3105 if (whole_heap_check_before_collection)
3106 sgen_check_whole_heap (FALSE);
3108 unpin_objects_from_queue (&unpin_queue);
3109 sgen_gray_object_queue_deinit (&unpin_queue);
3111 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3113 TV_GETTIME (total_end);
3114 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3116 current_collection_generation = -1;
3122 * Ensure an allocation request for @size will succeed by freeing enough memory.
3124 * LOCKING: The GC lock MUST be held.
3127 sgen_ensure_free_space (size_t size)
3129 int generation_to_collect = -1;
3130 const char *reason = NULL;
3133 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3134 if (sgen_need_major_collection (size)) {
3135 reason = "LOS overflow";
3136 generation_to_collect = GENERATION_OLD;
3139 if (degraded_mode) {
3140 if (sgen_need_major_collection (size)) {
3141 reason = "Degraded mode overflow";
3142 generation_to_collect = GENERATION_OLD;
3144 } else if (sgen_need_major_collection (size)) {
3145 reason = "Minor allowance";
3146 generation_to_collect = GENERATION_OLD;
3148 generation_to_collect = GENERATION_NURSERY;
3149 reason = "Nursery full";
3153 if (generation_to_collect == -1) {
3154 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3155 generation_to_collect = GENERATION_OLD;
3156 reason = "Finish concurrent collection";
3160 if (generation_to_collect == -1)
3162 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3166 * LOCKING: Assumes the GC lock is held.
3169 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3171 TV_DECLARE (gc_start);
3172 TV_DECLARE (gc_end);
3173 TV_DECLARE (gc_total_start);
3174 TV_DECLARE (gc_total_end);
3175 GGTimingInfo infos [2];
3176 int overflow_generation_to_collect = -1;
3177 int oldest_generation_collected = generation_to_collect;
3178 const char *overflow_reason = NULL;
3180 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3182 binary_protocol_collection_force (generation_to_collect);
3184 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3186 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3188 TV_GETTIME (gc_start);
3190 sgen_stop_world (generation_to_collect);
3192 TV_GETTIME (gc_total_start);
3194 if (concurrent_collection_in_progress) {
3196 * We update the concurrent collection. If it finished, we're done. If
3197 * not, and we've been asked to do a nursery collection, we do that.
3199 gboolean force_finish = wait_to_finish && generation_to_collect == GENERATION_OLD;
3201 if (major_update_or_finish_concurrent_collection (force_finish)) {
3202 oldest_generation_collected = GENERATION_OLD;
3203 } else if (generation_to_collect == GENERATION_NURSERY) {
3204 collect_nursery (NULL, FALSE);
3210 * If we've been asked to do a major collection, and the major collector wants to
3211 * run synchronously (to evacuate), we set the flag to do that.
3213 if (generation_to_collect == GENERATION_OLD &&
3214 allow_synchronous_major &&
3215 major_collector.want_synchronous_collection &&
3216 *major_collector.want_synchronous_collection) {
3217 wait_to_finish = TRUE;
3220 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3223 * There's no concurrent collection in progress. Collect the generation we're asked
3224 * to collect. If the major collector is concurrent and we're not forced to wait,
3225 * start a concurrent collection.
3227 // FIXME: extract overflow reason
3228 if (generation_to_collect == GENERATION_NURSERY) {
3229 if (collect_nursery (NULL, FALSE)) {
3230 overflow_generation_to_collect = GENERATION_OLD;
3231 overflow_reason = "Minor overflow";
3234 if (major_collector.is_concurrent && !wait_to_finish) {
3235 collect_nursery (NULL, FALSE);
3236 major_start_concurrent_collection (reason);
3237 // FIXME: set infos[0] properly
3241 if (major_do_collection (reason)) {
3242 overflow_generation_to_collect = GENERATION_NURSERY;
3243 overflow_reason = "Excessive pinning";
3247 TV_GETTIME (gc_end);
3249 memset (infos, 0, sizeof (infos));
3250 infos [0].generation = generation_to_collect;
3251 infos [0].reason = reason;
3252 infos [0].is_overflow = FALSE;
3253 infos [1].generation = -1;
3254 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3256 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3258 if (overflow_generation_to_collect != -1) {
3260 * We need to do an overflow collection, either because we ran out of memory
3261 * or the nursery is fully pinned.
3264 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3265 infos [1].generation = overflow_generation_to_collect;
3266 infos [1].reason = overflow_reason;
3267 infos [1].is_overflow = TRUE;
3268 infos [1].total_time = gc_end;
3270 if (overflow_generation_to_collect == GENERATION_NURSERY)
3271 collect_nursery (NULL, FALSE);
3273 major_do_collection (overflow_reason);
3275 TV_GETTIME (gc_end);
3276 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3278 /* keep events symmetric */
3279 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3281 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3284 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3286 /* this also sets the proper pointers for the next allocation */
3287 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3288 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3289 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3290 sgen_dump_pin_queue ();
3295 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3297 TV_GETTIME (gc_total_end);
3298 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3300 sgen_restart_world (oldest_generation_collected, infos);
3302 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3306 * ######################################################################
3307 * ######## Memory allocation from the OS
3308 * ######################################################################
3309 * This section of code deals with getting memory from the OS and
3310 * allocating memory for GC-internal data structures.
3311 * Internal memory can be handled with a freelist for small objects.
3317 G_GNUC_UNUSED static void
3318 report_internal_mem_usage (void)
3320 printf ("Internal memory usage:\n");
3321 sgen_report_internal_mem_usage ();
3322 printf ("Pinned memory usage:\n");
3323 major_collector.report_pinned_memory_usage ();
3327 * ######################################################################
3328 * ######## Finalization support
3329 * ######################################################################
3332 static inline gboolean
3333 sgen_major_is_object_alive (void *object)
3337 /* Oldgen objects can be pinned and forwarded too */
3338 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3342 * FIXME: major_collector.is_object_live() also calculates the
3343 * size. Avoid the double calculation.
3345 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3346 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3347 return sgen_los_object_is_pinned (object);
3349 return major_collector.is_object_live (object);
3353 * If the object has been forwarded it means it's still referenced from a root.
3354 * If it is pinned it's still alive as well.
3355 * A LOS object is only alive if we have pinned it.
3356 * Return TRUE if @obj is ready to be finalized.
3358 static inline gboolean
3359 sgen_is_object_alive (void *object)
3361 if (ptr_in_nursery (object))
3362 return sgen_nursery_is_object_alive (object);
3364 return sgen_major_is_object_alive (object);
3368 * This function returns true if @object is either alive or it belongs to the old gen
3369 * and we're currently doing a minor collection.
3372 sgen_is_object_alive_for_current_gen (char *object)
3374 if (ptr_in_nursery (object))
3375 return sgen_nursery_is_object_alive (object);
3377 if (current_collection_generation == GENERATION_NURSERY)
3380 return sgen_major_is_object_alive (object);
3384 * This function returns true if @object is either alive and belongs to the
3385 * current collection - major collections are full heap, so old gen objects
3386 * are never alive during a minor collection.
3389 sgen_is_object_alive_and_on_current_collection (char *object)
3391 if (ptr_in_nursery (object))
3392 return sgen_nursery_is_object_alive (object);
3394 if (current_collection_generation == GENERATION_NURSERY)
3397 return sgen_major_is_object_alive (object);
3402 sgen_gc_is_object_ready_for_finalization (void *object)
3404 return !sgen_is_object_alive (object);
3408 has_critical_finalizer (MonoObject *obj)
3412 if (!mono_defaults.critical_finalizer_object)
3415 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3417 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3421 is_finalization_aware (MonoObject *obj)
3423 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3424 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3428 sgen_queue_finalization_entry (MonoObject *obj)
3430 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3431 gboolean critical = has_critical_finalizer (obj);
3432 entry->object = obj;
3434 entry->next = critical_fin_list;
3435 critical_fin_list = entry;
3437 entry->next = fin_ready_list;
3438 fin_ready_list = entry;
3441 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3442 fin_callbacks.object_queued_for_finalization (obj);
3444 #ifdef ENABLE_DTRACE
3445 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3446 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3447 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3448 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3449 vt->klass->name_space, vt->klass->name, gen, critical);
3455 sgen_object_is_live (void *obj)
3457 return sgen_is_object_alive_and_on_current_collection (obj);
3460 /* LOCKING: requires that the GC lock is held */
3462 null_ephemerons_for_domain (MonoDomain *domain)
3464 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3467 MonoObject *object = (MonoObject*)current->array;
3469 if (object && !object->vtable) {
3470 EphemeronLinkNode *tmp = current;
3473 prev->next = current->next;
3475 ephemeron_list = current->next;
3477 current = current->next;
3478 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3481 current = current->next;
3486 /* LOCKING: requires that the GC lock is held */
3488 clear_unreachable_ephemerons (ScanCopyContext ctx)
3490 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3491 GrayQueue *queue = ctx.queue;
3492 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3494 Ephemeron *cur, *array_end;
3498 char *object = current->array;
3500 if (!sgen_is_object_alive_for_current_gen (object)) {
3501 EphemeronLinkNode *tmp = current;
3503 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3506 prev->next = current->next;
3508 ephemeron_list = current->next;
3510 current = current->next;
3511 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3516 copy_func ((void**)&object, queue);
3517 current->array = object;
3519 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3521 array = (MonoArray*)object;
3522 cur = mono_array_addr (array, Ephemeron, 0);
3523 array_end = cur + mono_array_length_fast (array);
3524 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3526 for (; cur < array_end; ++cur) {
3527 char *key = (char*)cur->key;
3529 if (!key || key == tombstone)
3532 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3533 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3534 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3536 if (!sgen_is_object_alive_for_current_gen (key)) {
3537 cur->key = tombstone;
3543 current = current->next;
3548 LOCKING: requires that the GC lock is held
3550 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3553 mark_ephemerons_in_range (ScanCopyContext ctx)
3555 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3556 GrayQueue *queue = ctx.queue;
3557 int nothing_marked = 1;
3558 EphemeronLinkNode *current = ephemeron_list;
3560 Ephemeron *cur, *array_end;
3563 for (current = ephemeron_list; current; current = current->next) {
3564 char *object = current->array;
3565 SGEN_LOG (5, "Ephemeron array at %p", object);
3567 /*It has to be alive*/
3568 if (!sgen_is_object_alive_for_current_gen (object)) {
3569 SGEN_LOG (5, "\tnot reachable");
3573 copy_func ((void**)&object, queue);
3575 array = (MonoArray*)object;
3576 cur = mono_array_addr (array, Ephemeron, 0);
3577 array_end = cur + mono_array_length_fast (array);
3578 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3580 for (; cur < array_end; ++cur) {
3581 char *key = cur->key;
3583 if (!key || key == tombstone)
3586 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3587 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3588 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3590 if (sgen_is_object_alive_for_current_gen (key)) {
3591 char *value = cur->value;
3593 copy_func ((void**)&cur->key, queue);
3595 if (!sgen_is_object_alive_for_current_gen (value))
3597 copy_func ((void**)&cur->value, queue);
3603 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3604 return nothing_marked;
3608 mono_gc_invoke_finalizers (void)
3610 FinalizeReadyEntry *entry = NULL;
3611 gboolean entry_is_critical = FALSE;
3614 /* FIXME: batch to reduce lock contention */
3615 while (fin_ready_list || critical_fin_list) {
3619 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3621 /* We have finalized entry in the last
3622 interation, now we need to remove it from
3625 *list = entry->next;
3627 FinalizeReadyEntry *e = *list;
3628 while (e->next != entry)
3630 e->next = entry->next;
3632 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3636 /* Now look for the first non-null entry. */
3637 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3640 entry_is_critical = FALSE;
3642 entry_is_critical = TRUE;
3643 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3648 g_assert (entry->object);
3649 num_ready_finalizers--;
3650 obj = entry->object;
3651 entry->object = NULL;
3652 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3660 g_assert (entry->object == NULL);
3662 /* the object is on the stack so it is pinned */
3663 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3664 mono_gc_run_finalize (obj, NULL);
3671 mono_gc_pending_finalizers (void)
3673 return fin_ready_list || critical_fin_list;
3677 * ######################################################################
3678 * ######## registered roots support
3679 * ######################################################################
3683 * We do not coalesce roots.
3686 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3688 RootRecord new_root;
3691 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3692 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3693 /* we allow changing the size and the descriptor (for thread statics etc) */
3695 size_t old_size = root->end_root - start;
3696 root->end_root = start + size;
3697 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3698 ((root->root_desc == 0) && (descr == NULL)));
3699 root->root_desc = (mword)descr;
3701 roots_size -= old_size;
3707 new_root.end_root = start + size;
3708 new_root.root_desc = (mword)descr;
3710 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3713 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);
3720 mono_gc_register_root (char *start, size_t size, void *descr)
3722 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3726 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3728 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3732 mono_gc_deregister_root (char* addr)
3738 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3739 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3740 roots_size -= (root.end_root - addr);
3746 * ######################################################################
3747 * ######## Thread handling (stop/start code)
3748 * ######################################################################
3751 unsigned int sgen_global_stop_count = 0;
3754 sgen_get_current_collection_generation (void)
3756 return current_collection_generation;
3760 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3762 gc_callbacks = *callbacks;
3766 mono_gc_get_gc_callbacks ()
3768 return &gc_callbacks;
3771 /* Variables holding start/end nursery so it won't have to be passed at every call */
3772 static void *scan_area_arg_start, *scan_area_arg_end;
3775 mono_gc_conservatively_scan_area (void *start, void *end)
3777 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3781 mono_gc_scan_object (void *obj, void *gc_data)
3783 UserCopyOrMarkData *data = gc_data;
3784 current_object_ops.copy_or_mark_object (&obj, data->queue);
3789 * Mark from thread stacks and registers.
3792 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3794 SgenThreadInfo *info;
3796 scan_area_arg_start = start_nursery;
3797 scan_area_arg_end = end_nursery;
3799 FOREACH_THREAD (info) {
3801 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);
3804 if (info->gc_disabled) {
3805 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);
3808 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3809 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));
3812 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 ());
3813 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3814 UserCopyOrMarkData data = { NULL, queue };
3815 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3816 } else if (!precise) {
3817 if (!conservative_stack_mark) {
3818 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3819 conservative_stack_mark = TRUE;
3821 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3826 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3827 start_nursery, end_nursery, PIN_TYPE_STACK);
3829 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3830 start_nursery, end_nursery, PIN_TYPE_STACK);
3833 } END_FOREACH_THREAD
3837 ptr_on_stack (void *ptr)
3839 gpointer stack_start = &stack_start;
3840 SgenThreadInfo *info = mono_thread_info_current ();
3842 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3848 sgen_thread_register (SgenThreadInfo* info, void *addr)
3851 guint8 *staddr = NULL;
3853 #ifndef HAVE_KW_THREAD
3854 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3856 g_assert (!mono_native_tls_get_value (thread_info_key));
3857 mono_native_tls_set_value (thread_info_key, info);
3859 sgen_thread_info = info;
3862 #ifdef SGEN_POSIX_STW
3863 info->stop_count = -1;
3867 info->stack_start = NULL;
3868 info->stopped_ip = NULL;
3869 info->stopped_domain = NULL;
3871 memset (&info->ctx, 0, sizeof (MonoContext));
3873 memset (&info->regs, 0, sizeof (info->regs));
3876 sgen_init_tlab_info (info);
3878 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3880 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3881 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3884 info->stack_start_limit = staddr;
3886 info->stack_end = staddr + stsize;
3888 gsize stack_bottom = (gsize)addr;
3889 stack_bottom += 4095;
3890 stack_bottom &= ~4095;
3891 info->stack_end = (char*)stack_bottom;
3894 #ifdef HAVE_KW_THREAD
3895 stack_end = info->stack_end;
3898 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3900 if (gc_callbacks.thread_attach_func)
3901 info->runtime_data = gc_callbacks.thread_attach_func ();
3906 sgen_thread_detach (SgenThreadInfo *p)
3908 /* If a delegate is passed to native code and invoked on a thread we dont
3909 * know about, the jit will register it with mono_jit_thread_attach, but
3910 * we have no way of knowing when that thread goes away. SGen has a TSD
3911 * so we assume that if the domain is still registered, we can detach
3914 if (mono_domain_get ())
3915 mono_thread_detach_internal (mono_thread_internal_current ());
3919 sgen_thread_unregister (SgenThreadInfo *p)
3921 MonoNativeThreadId tid;
3923 tid = mono_thread_info_get_tid (p);
3924 binary_protocol_thread_unregister ((gpointer)tid);
3925 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3927 #ifndef HAVE_KW_THREAD
3928 mono_native_tls_set_value (thread_info_key, NULL);
3930 sgen_thread_info = NULL;
3933 if (p->info.runtime_thread)
3934 mono_threads_add_joinable_thread ((gpointer)tid);
3936 if (gc_callbacks.thread_detach_func) {
3937 gc_callbacks.thread_detach_func (p->runtime_data);
3938 p->runtime_data = NULL;
3944 sgen_thread_attach (SgenThreadInfo *info)
3947 /*this is odd, can we get attached before the gc is inited?*/
3951 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3952 info->runtime_data = gc_callbacks.thread_attach_func ();
3955 mono_gc_register_thread (void *baseptr)
3957 return mono_thread_info_attach (baseptr) != NULL;
3961 * mono_gc_set_stack_end:
3963 * Set the end of the current threads stack to STACK_END. The stack space between
3964 * STACK_END and the real end of the threads stack will not be scanned during collections.
3967 mono_gc_set_stack_end (void *stack_end)
3969 SgenThreadInfo *info;
3972 info = mono_thread_info_current ();
3974 g_assert (stack_end < info->stack_end);
3975 info->stack_end = stack_end;
3980 #if USE_PTHREAD_INTERCEPT
3984 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3986 return pthread_create (new_thread, attr, start_routine, arg);
3990 mono_gc_pthread_join (pthread_t thread, void **retval)
3992 return pthread_join (thread, retval);
3996 mono_gc_pthread_detach (pthread_t thread)
3998 return pthread_detach (thread);
4002 mono_gc_pthread_exit (void *retval)
4004 mono_thread_info_detach ();
4005 pthread_exit (retval);
4006 g_assert_not_reached ();
4009 #endif /* USE_PTHREAD_INTERCEPT */
4012 * ######################################################################
4013 * ######## Write barriers
4014 * ######################################################################
4018 * Note: the write barriers first do the needed GC work and then do the actual store:
4019 * this way the value is visible to the conservative GC scan after the write barrier
4020 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4021 * the conservative scan, otherwise by the remembered set scan.
4024 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4026 HEAVY_STAT (++stat_wbarrier_set_field);
4027 if (ptr_in_nursery (field_ptr)) {
4028 *(void**)field_ptr = value;
4031 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4033 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4035 remset.wbarrier_set_field (obj, field_ptr, value);
4039 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4041 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4042 if (ptr_in_nursery (slot_ptr)) {
4043 *(void**)slot_ptr = value;
4046 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4048 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4050 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4054 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4056 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4057 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4058 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4059 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4063 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4064 if (binary_protocol_is_heavy_enabled ()) {
4066 for (i = 0; i < count; ++i) {
4067 gpointer dest = (gpointer*)dest_ptr + i;
4068 gpointer obj = *((gpointer*)src_ptr + i);
4070 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4075 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4078 static char *found_obj;
4081 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4083 char *ptr = user_data;
4085 if (ptr >= obj && ptr < obj + size) {
4086 g_assert (!found_obj);
4091 /* for use in the debugger */
4092 char* find_object_for_ptr (char *ptr);
4094 find_object_for_ptr (char *ptr)
4096 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4098 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4099 find_object_for_ptr_callback, ptr, TRUE);
4105 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4110 * Very inefficient, but this is debugging code, supposed to
4111 * be called from gdb, so we don't care.
4114 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4119 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4123 HEAVY_STAT (++stat_wbarrier_generic_store);
4125 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4126 /* FIXME: ptr_in_heap must be called with the GC lock held */
4127 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4128 char *start = find_object_for_ptr (ptr);
4129 MonoObject *value = *(MonoObject**)ptr;
4133 MonoObject *obj = (MonoObject*)start;
4134 if (obj->vtable->domain != value->vtable->domain)
4135 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4141 obj = *(gpointer*)ptr;
4143 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4145 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4146 SGEN_LOG (8, "Skipping remset at %p", ptr);
4151 * We need to record old->old pointer locations for the
4152 * concurrent collector.
4154 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4155 SGEN_LOG (8, "Skipping remset at %p", ptr);
4159 SGEN_LOG (8, "Adding remset at %p", ptr);
4161 remset.wbarrier_generic_nostore (ptr);
4165 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4167 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4168 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4169 if (ptr_in_nursery (value))
4170 mono_gc_wbarrier_generic_nostore (ptr);
4171 sgen_dummy_use (value);
4174 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4175 * as an atomic operation with release semantics.
4178 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4180 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4182 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4184 InterlockedWritePointer (ptr, value);
4186 if (ptr_in_nursery (value))
4187 mono_gc_wbarrier_generic_nostore (ptr);
4189 sgen_dummy_use (value);
4192 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4194 mword *dest = _dest;
4199 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4201 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4204 size -= SIZEOF_VOID_P;
4209 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4211 #define HANDLE_PTR(ptr,obj) do { \
4212 gpointer o = *(gpointer*)(ptr); \
4214 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4215 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4220 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4222 #define SCAN_OBJECT_NOVTABLE
4223 #include "sgen-scan-object.h"
4228 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4230 HEAVY_STAT (++stat_wbarrier_value_copy);
4231 g_assert (klass->valuetype);
4233 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4235 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4236 size_t element_size = mono_class_value_size (klass, NULL);
4237 size_t size = count * element_size;
4238 mono_gc_memmove_atomic (dest, src, size);
4242 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4243 if (binary_protocol_is_heavy_enabled ()) {
4244 size_t element_size = mono_class_value_size (klass, NULL);
4246 for (i = 0; i < count; ++i) {
4247 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4248 (char*)src + i * element_size - sizeof (MonoObject),
4249 (mword) klass->gc_descr);
4254 remset.wbarrier_value_copy (dest, src, count, klass);
4258 * mono_gc_wbarrier_object_copy:
4260 * Write barrier to call when obj is the result of a clone or copy of an object.
4263 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4267 HEAVY_STAT (++stat_wbarrier_object_copy);
4269 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4270 size = mono_object_class (obj)->instance_size;
4271 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4272 size - sizeof (MonoObject));
4276 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4277 if (binary_protocol_is_heavy_enabled ())
4278 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4281 remset.wbarrier_object_copy (obj, src);
4286 * ######################################################################
4287 * ######## Other mono public interface functions.
4288 * ######################################################################
4291 #define REFS_SIZE 128
4294 MonoGCReferences callback;
4298 MonoObject *refs [REFS_SIZE];
4299 uintptr_t offsets [REFS_SIZE];
4303 #define HANDLE_PTR(ptr,obj) do { \
4305 if (hwi->count == REFS_SIZE) { \
4306 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4310 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4311 hwi->refs [hwi->count++] = *(ptr); \
4316 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4318 mword desc = sgen_obj_get_descriptor (start);
4320 #include "sgen-scan-object.h"
4324 walk_references (char *start, size_t size, void *data)
4326 HeapWalkInfo *hwi = data;
4329 collect_references (hwi, start, size);
4330 if (hwi->count || !hwi->called)
4331 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4335 * mono_gc_walk_heap:
4336 * @flags: flags for future use
4337 * @callback: a function pointer called for each object in the heap
4338 * @data: a user data pointer that is passed to callback
4340 * This function can be used to iterate over all the live objects in the heap:
4341 * for each object, @callback is invoked, providing info about the object's
4342 * location in memory, its class, its size and the objects it references.
4343 * For each referenced object it's offset from the object address is
4344 * reported in the offsets array.
4345 * The object references may be buffered, so the callback may be invoked
4346 * multiple times for the same object: in all but the first call, the size
4347 * argument will be zero.
4348 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4349 * profiler event handler.
4351 * Returns: a non-zero value if the GC doesn't support heap walking
4354 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4359 hwi.callback = callback;
4362 sgen_clear_nursery_fragments ();
4363 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4365 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4366 sgen_los_iterate_objects (walk_references, &hwi);
4372 mono_gc_collect (int generation)
4377 sgen_perform_collection (0, generation, "user request", TRUE);
4382 mono_gc_max_generation (void)
4388 mono_gc_collection_count (int generation)
4390 if (generation == 0)
4391 return gc_stats.minor_gc_count;
4392 return gc_stats.major_gc_count;
4396 mono_gc_get_used_size (void)
4400 tot = los_memory_usage;
4401 tot += nursery_section->next_data - nursery_section->data;
4402 tot += major_collector.get_used_size ();
4403 /* FIXME: account for pinned objects */
4409 mono_gc_get_los_limit (void)
4411 return MAX_SMALL_OBJ_SIZE;
4415 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4417 mono_unichar2 *new_end = str->chars + new_length;
4419 /* zero the discarded string. This null-delimits the string and allows
4420 * the space to be reclaimed by SGen. */
4422 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4423 CHECK_CANARY_FOR_OBJECT (str);
4424 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4425 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4427 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4430 str->length = new_length;
4434 mono_gc_user_markers_supported (void)
4440 mono_object_is_alive (MonoObject* o)
4446 mono_gc_get_generation (MonoObject *obj)
4448 if (ptr_in_nursery (obj))
4454 mono_gc_enable_events (void)
4459 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4461 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4465 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4467 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4471 mono_gc_weak_link_get (void **link_addr)
4473 void * volatile *link_addr_volatile;
4477 link_addr_volatile = link_addr;
4478 ptr = (void*)*link_addr_volatile;
4480 * At this point we have a hidden pointer. If the GC runs
4481 * here, it will not recognize the hidden pointer as a
4482 * reference, and if the object behind it is not referenced
4483 * elsewhere, it will be freed. Once the world is restarted
4484 * we reveal the pointer, giving us a pointer to a freed
4485 * object. To make sure we don't return it, we load the
4486 * hidden pointer again. If it's still the same, we can be
4487 * sure the object reference is valid.
4490 obj = (MonoObject*) REVEAL_POINTER (ptr);
4494 mono_memory_barrier ();
4497 * During the second bridge processing step the world is
4498 * running again. That step processes all weak links once
4499 * more to null those that refer to dead objects. Before that
4500 * is completed, those links must not be followed, so we
4501 * conservatively wait for bridge processing when any weak
4502 * link is dereferenced.
4504 if (G_UNLIKELY (bridge_processing_in_progress))
4505 mono_gc_wait_for_bridge_processing ();
4507 if ((void*)*link_addr_volatile != ptr)
4514 mono_gc_ephemeron_array_add (MonoObject *obj)
4516 EphemeronLinkNode *node;
4520 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4525 node->array = (char*)obj;
4526 node->next = ephemeron_list;
4527 ephemeron_list = node;
4529 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4536 mono_gc_set_allow_synchronous_major (gboolean flag)
4538 if (!major_collector.is_concurrent)
4541 allow_synchronous_major = flag;
4546 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4550 result = func (data);
4551 UNLOCK_INTERRUPTION;
4556 mono_gc_is_gc_thread (void)
4560 result = mono_thread_info_current () != NULL;
4566 is_critical_method (MonoMethod *method)
4568 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4572 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4576 va_start (ap, description_format);
4578 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4579 vfprintf (stderr, description_format, ap);
4581 fprintf (stderr, " - %s", fallback);
4582 fprintf (stderr, "\n");
4588 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4591 double val = strtod (opt, &endptr);
4592 if (endptr == opt) {
4593 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4596 else if (val < min || val > max) {
4597 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4605 mono_gc_base_init (void)
4607 MonoThreadInfoCallbacks cb;
4610 char *major_collector_opt = NULL;
4611 char *minor_collector_opt = NULL;
4612 size_t max_heap = 0;
4613 size_t soft_limit = 0;
4616 gboolean debug_print_allowance = FALSE;
4617 double allowance_ratio = 0, save_target = 0;
4618 gboolean have_split_nursery = FALSE;
4619 gboolean cement_enabled = TRUE;
4622 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4625 /* already inited */
4628 /* being inited by another thread */
4632 /* we will init it */
4635 g_assert_not_reached ();
4637 } while (result != 0);
4639 SGEN_TV_GETTIME (sgen_init_timestamp);
4641 LOCK_INIT (gc_mutex);
4643 pagesize = mono_pagesize ();
4644 gc_debug_file = stderr;
4646 cb.thread_register = sgen_thread_register;
4647 cb.thread_detach = sgen_thread_detach;
4648 cb.thread_unregister = sgen_thread_unregister;
4649 cb.thread_attach = sgen_thread_attach;
4650 cb.mono_method_is_critical = (gpointer)is_critical_method;
4652 cb.thread_exit = mono_gc_pthread_exit;
4653 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4656 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4658 LOCK_INIT (sgen_interruption_mutex);
4659 LOCK_INIT (pin_queue_mutex);
4661 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4662 opts = g_strsplit (env, ",", -1);
4663 for (ptr = opts; *ptr; ++ptr) {
4665 if (g_str_has_prefix (opt, "major=")) {
4666 opt = strchr (opt, '=') + 1;
4667 major_collector_opt = g_strdup (opt);
4668 } else if (g_str_has_prefix (opt, "minor=")) {
4669 opt = strchr (opt, '=') + 1;
4670 minor_collector_opt = g_strdup (opt);
4678 sgen_init_internal_allocator ();
4679 sgen_init_nursery_allocator ();
4680 sgen_init_fin_weak_hash ();
4682 sgen_init_hash_table ();
4683 sgen_init_descriptors ();
4684 sgen_init_gray_queues ();
4686 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4687 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4688 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4689 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4691 #ifndef HAVE_KW_THREAD
4692 mono_native_tls_alloc (&thread_info_key, NULL);
4693 #if defined(__APPLE__) || defined (HOST_WIN32)
4695 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4696 * where the two are the same.
4698 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4702 int tls_offset = -1;
4703 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4704 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4709 * This needs to happen before any internal allocations because
4710 * it inits the small id which is required for hazard pointer
4715 mono_thread_info_attach (&dummy);
4717 if (!minor_collector_opt) {
4718 sgen_simple_nursery_init (&sgen_minor_collector);
4720 if (!strcmp (minor_collector_opt, "simple")) {
4722 sgen_simple_nursery_init (&sgen_minor_collector);
4723 } else if (!strcmp (minor_collector_opt, "split")) {
4724 sgen_split_nursery_init (&sgen_minor_collector);
4725 have_split_nursery = TRUE;
4727 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4728 goto use_simple_nursery;
4732 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4733 use_marksweep_major:
4734 sgen_marksweep_init (&major_collector);
4735 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4736 sgen_marksweep_conc_init (&major_collector);
4738 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4739 goto use_marksweep_major;
4742 ///* Keep this the default for now */
4743 /* Precise marking is broken on all supported targets. Disable until fixed. */
4744 conservative_stack_mark = TRUE;
4746 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4749 gboolean usage_printed = FALSE;
4751 for (ptr = opts; *ptr; ++ptr) {
4753 if (!strcmp (opt, ""))
4755 if (g_str_has_prefix (opt, "major="))
4757 if (g_str_has_prefix (opt, "minor="))
4759 if (g_str_has_prefix (opt, "max-heap-size=")) {
4760 size_t max_heap_candidate = 0;
4761 opt = strchr (opt, '=') + 1;
4762 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4763 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4764 if (max_heap != max_heap_candidate)
4765 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4767 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4771 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4772 opt = strchr (opt, '=') + 1;
4773 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4774 if (soft_limit <= 0) {
4775 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4779 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4783 if (g_str_has_prefix (opt, "stack-mark=")) {
4784 opt = strchr (opt, '=') + 1;
4785 if (!strcmp (opt, "precise")) {
4786 conservative_stack_mark = FALSE;
4787 } else if (!strcmp (opt, "conservative")) {
4788 conservative_stack_mark = TRUE;
4790 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4791 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4795 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4796 opt = strchr (opt, '=') + 1;
4797 sgen_set_bridge_implementation (opt);
4800 if (g_str_has_prefix (opt, "toggleref-test")) {
4801 sgen_register_test_toggleref_callback ();
4806 if (g_str_has_prefix (opt, "nursery-size=")) {
4808 opt = strchr (opt, '=') + 1;
4809 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4810 #ifdef SGEN_ALIGN_NURSERY
4811 if ((val & (val - 1))) {
4812 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4816 if (val < SGEN_MAX_NURSERY_WASTE) {
4817 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4818 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4822 sgen_nursery_size = val;
4823 sgen_nursery_bits = 0;
4824 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4827 sgen_nursery_size = val;
4830 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4836 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4838 opt = strchr (opt, '=') + 1;
4839 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4840 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4845 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4847 opt = strchr (opt, '=') + 1;
4848 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4849 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4850 allowance_ratio = val;
4854 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4855 if (!major_collector.is_concurrent) {
4856 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4860 opt = strchr (opt, '=') + 1;
4862 if (!strcmp (opt, "yes")) {
4863 allow_synchronous_major = TRUE;
4864 } else if (!strcmp (opt, "no")) {
4865 allow_synchronous_major = FALSE;
4867 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4872 if (!strcmp (opt, "cementing")) {
4873 cement_enabled = TRUE;
4876 if (!strcmp (opt, "no-cementing")) {
4877 cement_enabled = FALSE;
4881 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4884 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4887 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4892 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4893 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4894 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4895 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4896 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4897 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4898 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4899 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4900 fprintf (stderr, " [no-]cementing\n");
4901 if (major_collector.is_concurrent)
4902 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4903 if (major_collector.print_gc_param_usage)
4904 major_collector.print_gc_param_usage ();
4905 if (sgen_minor_collector.print_gc_param_usage)
4906 sgen_minor_collector.print_gc_param_usage ();
4907 fprintf (stderr, " Experimental options:\n");
4908 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4909 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);
4910 fprintf (stderr, "\n");
4912 usage_printed = TRUE;
4917 if (major_collector.is_concurrent)
4918 sgen_workers_init (1);
4920 if (major_collector_opt)
4921 g_free (major_collector_opt);
4923 if (minor_collector_opt)
4924 g_free (minor_collector_opt);
4928 sgen_cement_init (cement_enabled);
4930 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4931 gboolean usage_printed = FALSE;
4933 opts = g_strsplit (env, ",", -1);
4934 for (ptr = opts; ptr && *ptr; ptr ++) {
4936 if (!strcmp (opt, ""))
4938 if (opt [0] >= '0' && opt [0] <= '9') {
4939 gc_debug_level = atoi (opt);
4944 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4945 gc_debug_file = fopen (rf, "wb");
4947 gc_debug_file = stderr;
4950 } else if (!strcmp (opt, "print-allowance")) {
4951 debug_print_allowance = TRUE;
4952 } else if (!strcmp (opt, "print-pinning")) {
4953 do_pin_stats = TRUE;
4954 } else if (!strcmp (opt, "verify-before-allocs")) {
4955 verify_before_allocs = 1;
4956 has_per_allocation_action = TRUE;
4957 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4958 char *arg = strchr (opt, '=') + 1;
4959 verify_before_allocs = atoi (arg);
4960 has_per_allocation_action = TRUE;
4961 } else if (!strcmp (opt, "collect-before-allocs")) {
4962 collect_before_allocs = 1;
4963 has_per_allocation_action = TRUE;
4964 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4965 char *arg = strchr (opt, '=') + 1;
4966 has_per_allocation_action = TRUE;
4967 collect_before_allocs = atoi (arg);
4968 } else if (!strcmp (opt, "verify-before-collections")) {
4969 whole_heap_check_before_collection = TRUE;
4970 } else if (!strcmp (opt, "check-at-minor-collections")) {
4971 consistency_check_at_minor_collection = TRUE;
4972 nursery_clear_policy = CLEAR_AT_GC;
4973 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4974 if (!major_collector.is_concurrent) {
4975 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4978 mod_union_consistency_check = TRUE;
4979 } else if (!strcmp (opt, "check-mark-bits")) {
4980 check_mark_bits_after_major_collection = TRUE;
4981 } else if (!strcmp (opt, "check-nursery-pinned")) {
4982 check_nursery_objects_pinned = TRUE;
4983 } else if (!strcmp (opt, "xdomain-checks")) {
4984 xdomain_checks = TRUE;
4985 } else if (!strcmp (opt, "clear-at-gc")) {
4986 nursery_clear_policy = CLEAR_AT_GC;
4987 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4988 nursery_clear_policy = CLEAR_AT_GC;
4989 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4990 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4991 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4992 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4993 } else if (!strcmp (opt, "check-scan-starts")) {
4994 do_scan_starts_check = TRUE;
4995 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4996 do_verify_nursery = TRUE;
4997 } else if (!strcmp (opt, "check-concurrent")) {
4998 if (!major_collector.is_concurrent) {
4999 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5002 do_concurrent_checks = TRUE;
5003 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5004 do_dump_nursery_content = TRUE;
5005 } else if (!strcmp (opt, "no-managed-allocator")) {
5006 sgen_set_use_managed_allocator (FALSE);
5007 } else if (!strcmp (opt, "disable-minor")) {
5008 disable_minor_collections = TRUE;
5009 } else if (!strcmp (opt, "disable-major")) {
5010 disable_major_collections = TRUE;
5011 } else if (g_str_has_prefix (opt, "heap-dump=")) {
5012 char *filename = strchr (opt, '=') + 1;
5013 nursery_clear_policy = CLEAR_AT_GC;
5014 heap_dump_file = fopen (filename, "w");
5015 if (heap_dump_file) {
5016 fprintf (heap_dump_file, "<sgen-dump>\n");
5017 do_pin_stats = TRUE;
5019 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5020 char *filename = strchr (opt, '=') + 1;
5021 char *colon = strrchr (filename, ':');
5024 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
5025 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
5030 binary_protocol_init (filename, (long long)limit);
5031 } else if (!strcmp (opt, "nursery-canaries")) {
5032 do_verify_nursery = TRUE;
5033 sgen_set_use_managed_allocator (FALSE);
5034 enable_nursery_canaries = TRUE;
5035 } else if (!sgen_bridge_handle_gc_debug (opt)) {
5036 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5041 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);
5042 fprintf (stderr, "Valid <option>s are:\n");
5043 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5044 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5045 fprintf (stderr, " check-at-minor-collections\n");
5046 fprintf (stderr, " check-mark-bits\n");
5047 fprintf (stderr, " check-nursery-pinned\n");
5048 fprintf (stderr, " verify-before-collections\n");
5049 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5050 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5051 fprintf (stderr, " disable-minor\n");
5052 fprintf (stderr, " disable-major\n");
5053 fprintf (stderr, " xdomain-checks\n");
5054 fprintf (stderr, " check-concurrent\n");
5055 fprintf (stderr, " clear-[nursery-]at-gc\n");
5056 fprintf (stderr, " clear-at-tlab-creation\n");
5057 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5058 fprintf (stderr, " check-scan-starts\n");
5059 fprintf (stderr, " no-managed-allocator\n");
5060 fprintf (stderr, " print-allowance\n");
5061 fprintf (stderr, " print-pinning\n");
5062 fprintf (stderr, " heap-dump=<filename>\n");
5063 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5064 fprintf (stderr, " nursery-canaries\n");
5065 sgen_bridge_print_gc_debug_usage ();
5066 fprintf (stderr, "\n");
5068 usage_printed = TRUE;
5074 if (check_mark_bits_after_major_collection)
5075 nursery_clear_policy = CLEAR_AT_GC;
5077 if (major_collector.post_param_init)
5078 major_collector.post_param_init (&major_collector);
5080 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5082 memset (&remset, 0, sizeof (remset));
5084 sgen_card_table_init (&remset);
5090 mono_gc_get_gc_name (void)
5095 static MonoMethod *write_barrier_method;
5098 sgen_is_critical_method (MonoMethod *method)
5100 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5104 sgen_has_critical_method (void)
5106 return write_barrier_method || sgen_has_managed_allocator ();
5112 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5114 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5115 #ifdef SGEN_ALIGN_NURSERY
5116 // if (ptr_in_nursery (ptr)) return;
5118 * Masking out the bits might be faster, but we would have to use 64 bit
5119 * immediates, which might be slower.
5121 mono_mb_emit_ldarg (mb, 0);
5122 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5123 mono_mb_emit_byte (mb, CEE_SHR_UN);
5124 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5125 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5127 if (!major_collector.is_concurrent) {
5128 // if (!ptr_in_nursery (*ptr)) return;
5129 mono_mb_emit_ldarg (mb, 0);
5130 mono_mb_emit_byte (mb, CEE_LDIND_I);
5131 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5132 mono_mb_emit_byte (mb, CEE_SHR_UN);
5133 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5134 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5137 int label_continue1, label_continue2;
5138 int dereferenced_var;
5140 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5141 mono_mb_emit_ldarg (mb, 0);
5142 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5143 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5145 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5146 mono_mb_emit_ldarg (mb, 0);
5147 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5148 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5151 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5154 mono_mb_patch_branch (mb, label_continue_1);
5155 mono_mb_patch_branch (mb, label_continue_2);
5157 // Dereference and store in local var
5158 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5159 mono_mb_emit_ldarg (mb, 0);
5160 mono_mb_emit_byte (mb, CEE_LDIND_I);
5161 mono_mb_emit_stloc (mb, dereferenced_var);
5163 if (!major_collector.is_concurrent) {
5164 // if (*ptr < sgen_get_nursery_start ()) return;
5165 mono_mb_emit_ldloc (mb, dereferenced_var);
5166 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5167 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5169 // if (*ptr >= sgen_get_nursery_end ()) return;
5170 mono_mb_emit_ldloc (mb, dereferenced_var);
5171 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5172 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5179 mono_gc_get_write_barrier (void)
5182 MonoMethodBuilder *mb;
5183 MonoMethodSignature *sig;
5184 #ifdef MANAGED_WBARRIER
5185 int i, nursery_check_labels [3];
5187 #ifdef HAVE_KW_THREAD
5188 int stack_end_offset = -1;
5190 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5191 g_assert (stack_end_offset != -1);
5195 // FIXME: Maybe create a separate version for ctors (the branch would be
5196 // correctly predicted more times)
5197 if (write_barrier_method)
5198 return write_barrier_method;
5200 /* Create the IL version of mono_gc_barrier_generic_store () */
5201 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5202 sig->ret = &mono_defaults.void_class->byval_arg;
5203 sig->params [0] = &mono_defaults.int_class->byval_arg;
5205 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5208 #ifdef MANAGED_WBARRIER
5209 emit_nursery_check (mb, nursery_check_labels);
5211 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5215 LDC_PTR sgen_cardtable
5217 address >> CARD_BITS
5221 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5222 LDC_PTR card_table_mask
5229 mono_mb_emit_ptr (mb, sgen_cardtable);
5230 mono_mb_emit_ldarg (mb, 0);
5231 mono_mb_emit_icon (mb, CARD_BITS);
5232 mono_mb_emit_byte (mb, CEE_SHR_UN);
5233 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5234 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5235 mono_mb_emit_byte (mb, CEE_AND);
5237 mono_mb_emit_byte (mb, CEE_ADD);
5238 mono_mb_emit_icon (mb, 1);
5239 mono_mb_emit_byte (mb, CEE_STIND_I1);
5242 for (i = 0; i < 3; ++i) {
5243 if (nursery_check_labels [i])
5244 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5246 mono_mb_emit_byte (mb, CEE_RET);
5248 mono_mb_emit_ldarg (mb, 0);
5249 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5250 mono_mb_emit_byte (mb, CEE_RET);
5253 res = mono_mb_create_method (mb, sig, 16);
5257 if (write_barrier_method) {
5258 /* Already created */
5259 mono_free_method (res);
5261 /* double-checked locking */
5262 mono_memory_barrier ();
5263 write_barrier_method = res;
5267 return write_barrier_method;
5271 mono_gc_get_description (void)
5273 return g_strdup ("sgen");
5277 mono_gc_set_desktop_mode (void)
5282 mono_gc_is_moving (void)
5288 mono_gc_is_disabled (void)
5294 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5301 sgen_get_nursery_clear_policy (void)
5303 return nursery_clear_policy;
5307 sgen_get_array_fill_vtable (void)
5309 if (!array_fill_vtable) {
5310 static MonoClass klass;
5311 static MonoVTable vtable;
5314 MonoDomain *domain = mono_get_root_domain ();
5317 klass.element_class = mono_defaults.byte_class;
5319 klass.instance_size = sizeof (MonoArray);
5320 klass.sizes.element_size = 1;
5321 klass.name = "array_filler_type";
5323 vtable.klass = &klass;
5325 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5328 array_fill_vtable = &vtable;
5330 return array_fill_vtable;
5340 sgen_gc_unlock (void)
5342 gboolean try_free = sgen_try_free_some_memory;
5343 sgen_try_free_some_memory = FALSE;
5344 mono_mutex_unlock (&gc_mutex);
5345 MONO_GC_UNLOCKED ();
5347 mono_thread_hazardous_try_free_some ();
5351 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5353 major_collector.iterate_live_block_ranges (callback);
5357 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5359 major_collector.scan_card_table (FALSE, queue);
5363 sgen_get_major_collector (void)
5365 return &major_collector;
5368 void mono_gc_set_skip_thread (gboolean skip)
5370 SgenThreadInfo *info = mono_thread_info_current ();
5373 info->gc_disabled = skip;
5378 sgen_get_remset (void)
5384 mono_gc_get_vtable_bits (MonoClass *class)
5387 /* FIXME move this to the bridge code */
5388 if (sgen_need_bridge_processing ()) {
5389 switch (sgen_bridge_class_kind (class)) {
5390 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5391 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5392 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5394 case GC_BRIDGE_OPAQUE_CLASS:
5395 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5399 if (fin_callbacks.is_class_finalization_aware) {
5400 if (fin_callbacks.is_class_finalization_aware (class))
5401 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5407 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5414 sgen_check_whole_heap_stw (void)
5416 sgen_stop_world (0);
5417 sgen_clear_nursery_fragments ();
5418 sgen_check_whole_heap (FALSE);
5419 sgen_restart_world (0, NULL);
5423 sgen_gc_event_moves (void)
5425 if (moved_objects_idx) {
5426 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5427 moved_objects_idx = 0;
5432 sgen_timestamp (void)
5434 SGEN_TV_DECLARE (timestamp);
5435 SGEN_TV_GETTIME (timestamp);
5436 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5440 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5442 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5443 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5445 fin_callbacks = *callbacks;
5452 #endif /* HAVE_SGEN_GC */