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>
193 #include "metadata/sgen-gc.h"
194 #include "metadata/metadata-internals.h"
195 #include "metadata/class-internals.h"
196 #include "metadata/gc-internal.h"
197 #include "metadata/object-internals.h"
198 #include "metadata/threads.h"
199 #include "metadata/sgen-cardtable.h"
200 #include "metadata/sgen-protocol.h"
201 #include "metadata/sgen-archdep.h"
202 #include "metadata/sgen-bridge.h"
203 #include "metadata/sgen-memory-governor.h"
204 #include "metadata/sgen-hash-table.h"
205 #include "metadata/mono-gc.h"
206 #include "metadata/method-builder.h"
207 #include "metadata/profiler-private.h"
208 #include "metadata/monitor.h"
209 #include "metadata/mempool-internals.h"
210 #include "metadata/marshal.h"
211 #include "metadata/runtime.h"
212 #include "metadata/sgen-cardtable.h"
213 #include "metadata/sgen-pinning.h"
214 #include "metadata/sgen-workers.h"
215 #include "metadata/sgen-layout-stats.h"
216 #include "utils/mono-mmap.h"
217 #include "utils/mono-time.h"
218 #include "utils/mono-semaphore.h"
219 #include "utils/mono-counters.h"
220 #include "utils/mono-proclib.h"
221 #include "utils/mono-memory-model.h"
222 #include "utils/mono-logger-internal.h"
223 #include "utils/dtrace.h"
225 #include <mono/utils/mono-logger-internal.h>
226 #include <mono/utils/memcheck.h>
228 #if defined(__MACH__)
229 #include "utils/mach-support.h"
232 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
236 #include "mono/cil/opcode.def"
242 #undef pthread_create
244 #undef pthread_detach
247 * ######################################################################
248 * ######## Types and constants used by the GC.
249 * ######################################################################
252 /* 0 means not initialized, 1 is initialized, -1 means in progress */
253 static int gc_initialized = 0;
254 /* If set, check if we need to do something every X allocations */
255 gboolean has_per_allocation_action;
256 /* If set, do a heap check every X allocation */
257 guint32 verify_before_allocs = 0;
258 /* If set, do a minor collection before every X allocation */
259 guint32 collect_before_allocs = 0;
260 /* If set, do a whole heap check before each collection */
261 static gboolean whole_heap_check_before_collection = FALSE;
262 /* If set, do a heap consistency check before each minor collection */
263 static gboolean consistency_check_at_minor_collection = FALSE;
264 /* If set, do a mod union consistency check before each finishing collection pause */
265 static gboolean mod_union_consistency_check = FALSE;
266 /* If set, check whether mark bits are consistent after major collections */
267 static gboolean check_mark_bits_after_major_collection = FALSE;
268 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
269 static gboolean check_nursery_objects_pinned = FALSE;
270 /* If set, do a few checks when the concurrent collector is used */
271 static gboolean do_concurrent_checks = FALSE;
272 /* If set, check that there are no references to the domain left at domain unload */
273 static gboolean xdomain_checks = FALSE;
274 /* If not null, dump the heap after each collection into this file */
275 static FILE *heap_dump_file = NULL;
276 /* If set, mark stacks conservatively, even if precise marking is possible */
277 static gboolean conservative_stack_mark = FALSE;
278 /* If set, do a plausibility check on the scan_starts before and after
280 static gboolean do_scan_starts_check = FALSE;
281 /* If set, do not run finalizers. */
282 static gboolean do_not_finalize = FALSE;
285 * If the major collector is concurrent and this is FALSE, we will
286 * never initiate a synchronous major collection, unless requested via
289 static gboolean allow_synchronous_major = TRUE;
290 static gboolean disable_minor_collections = FALSE;
291 static gboolean disable_major_collections = FALSE;
292 gboolean do_pin_stats = FALSE;
293 static gboolean do_verify_nursery = FALSE;
294 static gboolean do_dump_nursery_content = FALSE;
295 static gboolean enable_nursery_canaries = FALSE;
297 #ifdef HEAVY_STATISTICS
298 guint64 stat_objects_alloced_degraded = 0;
299 guint64 stat_bytes_alloced_degraded = 0;
301 guint64 stat_copy_object_called_nursery = 0;
302 guint64 stat_objects_copied_nursery = 0;
303 guint64 stat_copy_object_called_major = 0;
304 guint64 stat_objects_copied_major = 0;
306 guint64 stat_scan_object_called_nursery = 0;
307 guint64 stat_scan_object_called_major = 0;
309 guint64 stat_slots_allocated_in_vain;
311 guint64 stat_nursery_copy_object_failed_from_space = 0;
312 guint64 stat_nursery_copy_object_failed_forwarded = 0;
313 guint64 stat_nursery_copy_object_failed_pinned = 0;
314 guint64 stat_nursery_copy_object_failed_to_space = 0;
316 static int stat_wbarrier_add_to_global_remset = 0;
317 static int stat_wbarrier_set_field = 0;
318 static int stat_wbarrier_set_arrayref = 0;
319 static int stat_wbarrier_arrayref_copy = 0;
320 static int stat_wbarrier_generic_store = 0;
321 static int stat_wbarrier_generic_store_atomic = 0;
322 static int stat_wbarrier_set_root = 0;
323 static int stat_wbarrier_value_copy = 0;
324 static int stat_wbarrier_object_copy = 0;
327 static guint64 stat_pinned_objects = 0;
329 static guint64 time_minor_pre_collection_fragment_clear = 0;
330 static guint64 time_minor_pinning = 0;
331 static guint64 time_minor_scan_remsets = 0;
332 static guint64 time_minor_scan_pinned = 0;
333 static guint64 time_minor_scan_registered_roots = 0;
334 static guint64 time_minor_scan_thread_data = 0;
335 static guint64 time_minor_finish_gray_stack = 0;
336 static guint64 time_minor_fragment_creation = 0;
338 static guint64 time_major_pre_collection_fragment_clear = 0;
339 static guint64 time_major_pinning = 0;
340 static guint64 time_major_scan_pinned = 0;
341 static guint64 time_major_scan_registered_roots = 0;
342 static guint64 time_major_scan_thread_data = 0;
343 static guint64 time_major_scan_alloc_pinned = 0;
344 static guint64 time_major_scan_finalized = 0;
345 static guint64 time_major_scan_big_objects = 0;
346 static guint64 time_major_finish_gray_stack = 0;
347 static guint64 time_major_free_bigobjs = 0;
348 static guint64 time_major_los_sweep = 0;
349 static guint64 time_major_sweep = 0;
350 static guint64 time_major_fragment_creation = 0;
352 static guint64 time_max = 0;
354 static SGEN_TV_DECLARE (time_major_conc_collection_start);
355 static SGEN_TV_DECLARE (time_major_conc_collection_end);
357 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
358 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
360 int gc_debug_level = 0;
363 static MonoGCFinalizerCallbacks fin_callbacks;
367 mono_gc_flush_info (void)
369 fflush (gc_debug_file);
373 #define TV_DECLARE SGEN_TV_DECLARE
374 #define TV_GETTIME SGEN_TV_GETTIME
375 #define TV_ELAPSED SGEN_TV_ELAPSED
377 SGEN_TV_DECLARE (sgen_init_timestamp);
379 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
381 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
383 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
384 #define object_is_pinned SGEN_OBJECT_IS_PINNED
385 #define pin_object SGEN_PIN_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);
433 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
434 struct _FinalizeReadyEntry {
435 FinalizeReadyEntry *next;
439 typedef struct _EphemeronLinkNode EphemeronLinkNode;
441 struct _EphemeronLinkNode {
442 EphemeronLinkNode *next;
451 int current_collection_generation = -1;
452 volatile gboolean concurrent_collection_in_progress = FALSE;
454 /* objects that are ready to be finalized */
455 static FinalizeReadyEntry *fin_ready_list = NULL;
456 static FinalizeReadyEntry *critical_fin_list = NULL;
458 static EphemeronLinkNode *ephemeron_list;
460 /* registered roots: the key to the hash is the root start address */
462 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
464 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
465 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
466 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
467 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
469 static mword roots_size = 0; /* amount of memory in the root set */
471 #define GC_ROOT_NUM 32
473 int count; /* must be the first field */
474 void *objects [GC_ROOT_NUM];
475 int root_types [GC_ROOT_NUM];
476 uintptr_t extra_info [GC_ROOT_NUM];
480 notify_gc_roots (GCRootReport *report)
484 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
489 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
491 if (report->count == GC_ROOT_NUM)
492 notify_gc_roots (report);
493 report->objects [report->count] = object;
494 report->root_types [report->count] = rtype;
495 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
498 MonoNativeTlsKey thread_info_key;
500 #ifdef HAVE_KW_THREAD
501 __thread SgenThreadInfo *sgen_thread_info;
502 __thread char *stack_end;
505 /* The size of a TLAB */
506 /* The bigger the value, the less often we have to go to the slow path to allocate a new
507 * one, but the more space is wasted by threads not allocating much memory.
509 * FIXME: Make this self-tuning for each thread.
511 guint32 tlab_size = (1024 * 4);
513 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
515 /* Functions supplied by the runtime to be called by the GC */
516 static MonoGCCallbacks gc_callbacks;
518 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
520 #define ALIGN_UP SGEN_ALIGN_UP
522 #define MOVED_OBJECTS_NUM 64
523 static void *moved_objects [MOVED_OBJECTS_NUM];
524 static int moved_objects_idx = 0;
526 /* Vtable of the objects used to fill out nursery fragments before a collection */
527 static MonoVTable *array_fill_vtable;
529 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
530 MonoNativeThreadId main_gc_thread = NULL;
533 /*Object was pinned during the current collection*/
534 static mword objects_pinned;
537 * ######################################################################
538 * ######## Macros and function declarations.
539 * ######################################################################
543 align_pointer (void *ptr)
545 mword p = (mword)ptr;
546 p += sizeof (gpointer) - 1;
547 p &= ~ (sizeof (gpointer) - 1);
551 typedef SgenGrayQueue GrayQueue;
553 /* forward declarations */
554 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
555 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
556 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
557 static void report_finalizer_roots (void);
558 static void report_registered_roots (void);
560 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
561 static void finish_gray_stack (int generation, GrayQueue *queue);
563 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
566 static void init_stats (void);
568 static int mark_ephemerons_in_range (ScanCopyContext ctx);
569 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
570 static void null_ephemerons_for_domain (MonoDomain *domain);
572 SgenObjectOperations current_object_ops;
573 SgenMajorCollector major_collector;
574 SgenMinorCollector sgen_minor_collector;
575 static GrayQueue gray_queue;
577 static SgenRemeberedSet remset;
579 /* The gray queue to use from the main collection thread. */
580 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
583 * The gray queue a worker job must use. If we're not parallel or
584 * concurrent, we use the main gray queue.
586 static SgenGrayQueue*
587 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
589 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
593 gray_queue_redirect (SgenGrayQueue *queue)
595 gboolean wake = FALSE;
598 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
601 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
606 g_assert (concurrent_collection_in_progress);
607 if (sgen_workers_have_started ()) {
608 sgen_workers_ensure_awake ();
610 if (concurrent_collection_in_progress)
611 g_assert (current_collection_generation == -1);
617 gray_queue_enable_redirect (SgenGrayQueue *queue)
619 if (!concurrent_collection_in_progress)
622 sgen_gray_queue_set_alloc_prepare (queue, gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
623 gray_queue_redirect (queue);
627 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
629 while (start < end) {
633 if (!*(void**)start) {
634 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
639 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
645 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
646 CHECK_CANARY_FOR_OBJECT (obj);
647 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
648 callback (obj, size, data);
649 CANARIFY_SIZE (size);
651 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
659 need_remove_object_for_domain (char *start, MonoDomain *domain)
661 if (mono_object_domain (start) == domain) {
662 SGEN_LOG (4, "Need to cleanup object %p", start);
663 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
670 process_object_for_domain_clearing (char *start, MonoDomain *domain)
672 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
673 if (vt->klass == mono_defaults.internal_thread_class)
674 g_assert (mono_object_domain (start) == mono_get_root_domain ());
675 /* The object could be a proxy for an object in the domain
677 #ifndef DISABLE_REMOTING
678 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
679 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
681 /* The server could already have been zeroed out, so
682 we need to check for that, too. */
683 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
684 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
685 ((MonoRealProxy*)start)->unwrapped_server = NULL;
692 clear_domain_process_object (char *obj, MonoDomain *domain)
696 process_object_for_domain_clearing (obj, domain);
697 remove = need_remove_object_for_domain (obj, domain);
699 if (remove && ((MonoObject*)obj)->synchronisation) {
700 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
702 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
709 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
711 if (clear_domain_process_object (obj, domain)) {
712 CANARIFY_SIZE (size);
713 memset (obj, 0, size);
718 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
720 clear_domain_process_object (obj, domain);
724 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
726 if (need_remove_object_for_domain (obj, domain))
727 major_collector.free_non_pinned_object (obj, size);
731 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
733 if (need_remove_object_for_domain (obj, domain))
734 major_collector.free_pinned_object (obj, size);
738 * When appdomains are unloaded we can easily remove objects that have finalizers,
739 * but all the others could still be present in random places on the heap.
740 * We need a sweep to get rid of them even though it's going to be costly
742 * The reason we need to remove them is because we access the vtable and class
743 * structures to know the object size and the reference bitmap: once the domain is
744 * unloaded the point to random memory.
747 mono_gc_clear_domain (MonoDomain * domain)
749 LOSObject *bigobj, *prev;
754 binary_protocol_domain_unload_begin (domain);
758 if (concurrent_collection_in_progress)
759 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
760 g_assert (!concurrent_collection_in_progress);
762 sgen_process_fin_stage_entries ();
763 sgen_process_dislink_stage_entries ();
765 sgen_clear_nursery_fragments ();
767 if (xdomain_checks && domain != mono_get_root_domain ()) {
768 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
769 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
770 sgen_check_for_xdomain_refs ();
773 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
774 to memory returned to the OS.*/
775 null_ephemerons_for_domain (domain);
777 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
778 sgen_null_links_for_domain (domain, i);
780 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
781 sgen_remove_finalizers_for_domain (domain, i);
783 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
784 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
786 /* We need two passes over major and large objects because
787 freeing such objects might give their memory back to the OS
788 (in the case of large objects) or obliterate its vtable
789 (pinned objects with major-copying or pinned and non-pinned
790 objects with major-mark&sweep), but we might need to
791 dereference a pointer from an object to another object if
792 the first object is a proxy. */
793 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
794 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
795 clear_domain_process_object (bigobj->data, domain);
798 for (bigobj = los_object_list; bigobj;) {
799 if (need_remove_object_for_domain (bigobj->data, domain)) {
800 LOSObject *to_free = bigobj;
802 prev->next = bigobj->next;
804 los_object_list = bigobj->next;
805 bigobj = bigobj->next;
806 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
807 sgen_los_free_object (to_free);
811 bigobj = bigobj->next;
813 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
814 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
816 if (domain == mono_get_root_domain ()) {
817 if (G_UNLIKELY (do_pin_stats))
818 sgen_pin_stats_print_class_stats ();
819 sgen_object_layout_dump (stdout);
822 sgen_restart_world (0, NULL);
824 binary_protocol_domain_unload_end (domain);
825 binary_protocol_flush_buffers (FALSE);
831 * sgen_add_to_global_remset:
833 * The global remset contains locations which point into newspace after
834 * a minor collection. This can happen if the objects they point to are pinned.
836 * LOCKING: If called from a parallel collector, the global remset
837 * lock must be held. For serial collectors that is not necessary.
840 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
842 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
844 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
846 if (!major_collector.is_concurrent) {
847 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
849 if (current_collection_generation == -1)
850 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
853 if (!object_is_pinned (obj))
854 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");
855 else if (sgen_cement_lookup_or_register (obj))
858 remset.record_pointer (ptr);
860 if (G_UNLIKELY (do_pin_stats))
861 sgen_pin_stats_register_global_remset (obj);
863 SGEN_LOG (8, "Adding global remset for %p", ptr);
864 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
868 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
869 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
870 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
871 vt->klass->name_space, vt->klass->name);
877 * sgen_drain_gray_stack:
879 * Scan objects in the gray stack until the stack is empty. This should be called
880 * frequently after each object is copied, to achieve better locality and cache
883 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
887 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
889 ScanObjectFunc scan_func = ctx.scan_func;
890 GrayQueue *queue = ctx.queue;
892 if (current_collection_generation == GENERATION_OLD && major_collector.drain_gray_stack)
893 return major_collector.drain_gray_stack (ctx);
897 for (i = 0; i != max_objs; ++i) {
900 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
903 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
904 scan_func (obj, desc, queue);
906 } while (max_objs < 0);
911 * Addresses in the pin queue are already sorted. This function finds
912 * the object header for each address and pins the object. The
913 * addresses must be inside the nursery section. The (start of the)
914 * address array is overwritten with the addresses of the actually
915 * pinned objects. Return the number of pinned objects.
918 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
920 GCMemSection *section = nursery_section;
921 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
922 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
923 void *start_nursery = section->data;
924 void *end_nursery = section->next_data;
929 void *pinning_front = start_nursery;
931 void **definitely_pinned = start;
932 ScanObjectFunc scan_func = ctx.scan_func;
933 SgenGrayQueue *queue = ctx.queue;
935 sgen_nursery_allocator_prepare_for_pinning ();
937 while (start < end) {
938 void *obj_to_pin = NULL;
939 size_t obj_to_pin_size = 0;
944 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
945 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
952 SGEN_LOG (5, "Considering pinning addr %p", addr);
953 /* We've already processed everything up to pinning_front. */
954 if (addr < pinning_front) {
960 * Find the closest scan start <= addr. We might search backward in the
961 * scan_starts array because entries might be NULL. In the worst case we
962 * start at start_nursery.
964 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
965 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
966 search_start = (void*)section->scan_starts [idx];
967 if (!search_start || search_start > addr) {
970 search_start = section->scan_starts [idx];
971 if (search_start && search_start <= addr)
974 if (!search_start || search_start > addr)
975 search_start = start_nursery;
979 * If the pinning front is closer than the scan start we found, start
980 * searching at the front.
982 if (search_start < pinning_front)
983 search_start = pinning_front;
986 * Now addr should be in an object a short distance from search_start.
988 * search_start must point to zeroed mem or point to an object.
991 size_t obj_size, canarified_obj_size;
994 if (!*(void**)search_start) {
995 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
996 /* The loop condition makes sure we don't overrun addr. */
1000 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
1003 * Filler arrays are marked by an invalid sync word. We don't
1004 * consider them for pinning. They are not delimited by canaries,
1007 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
1008 CHECK_CANARY_FOR_OBJECT (search_start);
1009 CANARIFY_SIZE (canarified_obj_size);
1011 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
1012 /* This is the object we're looking for. */
1013 obj_to_pin = search_start;
1014 obj_to_pin_size = canarified_obj_size;
1019 /* Skip to the next object */
1020 search_start = (void*)((char*)search_start + canarified_obj_size);
1021 } while (search_start <= addr);
1023 /* We've searched past the address we were looking for. */
1025 pinning_front = search_start;
1026 goto next_pin_queue_entry;
1030 * We've found an object to pin. It might still be a dummy array, but we
1031 * can advance the pinning front in any case.
1033 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1036 * If this is a dummy array marking the beginning of a nursery
1037 * fragment, we don't pin it.
1039 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1040 goto next_pin_queue_entry;
1043 * Finally - pin the object!
1045 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1047 scan_func (obj_to_pin, desc, queue);
1049 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1050 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1051 binary_protocol_pin (obj_to_pin,
1052 (gpointer)LOAD_VTABLE (obj_to_pin),
1053 safe_object_get_size (obj_to_pin));
1055 #ifdef ENABLE_DTRACE
1056 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1057 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1058 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1059 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1060 sgen_safe_object_get_size (obj_to_pin),
1061 vt->klass->name_space, vt->klass->name, gen);
1065 pin_object (obj_to_pin);
1066 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1067 if (G_UNLIKELY (do_pin_stats))
1068 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1069 definitely_pinned [count] = obj_to_pin;
1073 next_pin_queue_entry:
1077 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1078 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1079 GCRootReport report;
1081 for (idx = 0; idx < count; ++idx)
1082 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1083 notify_gc_roots (&report);
1085 stat_pinned_objects += count;
1090 pin_objects_in_nursery (ScanCopyContext ctx)
1094 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
1097 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1098 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
1103 sgen_pin_object (void *object, GrayQueue *queue)
1105 SGEN_PIN_OBJECT (object);
1106 sgen_pin_stage_ptr (object);
1108 if (G_UNLIKELY (do_pin_stats))
1109 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1111 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1112 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1114 #ifdef ENABLE_DTRACE
1115 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1116 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1117 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1118 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1124 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1128 gboolean major_pinned = FALSE;
1130 if (sgen_ptr_in_nursery (obj)) {
1131 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1132 sgen_pin_object (obj, queue);
1136 major_collector.pin_major_object (obj, queue);
1137 major_pinned = TRUE;
1140 vtable_word = *(mword*)obj;
1141 /*someone else forwarded it, update the pointer and bail out*/
1142 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1143 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1147 /*someone pinned it, nothing to do.*/
1148 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1153 /* Sort the addresses in array in increasing order.
1154 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1157 sgen_sort_addresses (void **array, size_t size)
1162 for (i = 1; i < size; ++i) {
1165 size_t parent = (child - 1) / 2;
1167 if (array [parent] >= array [child])
1170 tmp = array [parent];
1171 array [parent] = array [child];
1172 array [child] = tmp;
1178 for (i = size - 1; i > 0; --i) {
1181 array [i] = array [0];
1187 while (root * 2 + 1 <= end) {
1188 size_t child = root * 2 + 1;
1190 if (child < end && array [child] < array [child + 1])
1192 if (array [root] >= array [child])
1196 array [root] = array [child];
1197 array [child] = tmp;
1205 * Scan the memory between start and end and queue values which could be pointers
1206 * to the area between start_nursery and end_nursery for later consideration.
1207 * Typically used for thread stacks.
1210 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1214 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1215 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1218 while (start < end) {
1219 if (*start >= start_nursery && *start < end_nursery) {
1221 * *start can point to the middle of an object
1222 * note: should we handle pointing at the end of an object?
1223 * pinning in C# code disallows pointing at the end of an object
1224 * but there is some small chance that an optimizing C compiler
1225 * may keep the only reference to an object by pointing
1226 * at the end of it. We ignore this small chance for now.
1227 * Pointers to the end of an object are indistinguishable
1228 * from pointers to the start of the next object in memory
1229 * so if we allow that we'd need to pin two objects...
1230 * We queue the pointer in an array, the
1231 * array will then be sorted and uniqued. This way
1232 * we can coalesce several pinning pointers and it should
1233 * be faster since we'd do a memory scan with increasing
1234 * addresses. Note: we can align the address to the allocation
1235 * alignment, so the unique process is more effective.
1237 mword addr = (mword)*start;
1238 addr &= ~(ALLOC_ALIGN - 1);
1239 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1240 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1241 sgen_pin_stage_ptr ((void*)addr);
1242 binary_protocol_pin_stage (start, (void*)addr);
1245 if (G_UNLIKELY (do_pin_stats)) {
1246 if (ptr_in_nursery ((void*)addr))
1247 sgen_pin_stats_register_address ((char*)addr, pin_type);
1253 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1257 * The first thing we do in a collection is to identify pinned objects.
1258 * This function considers all the areas of memory that need to be
1259 * conservatively scanned.
1262 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1266 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);
1267 /* objects pinned from the API are inside these roots */
1268 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1269 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1270 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1271 } SGEN_HASH_TABLE_FOREACH_END;
1272 /* now deal with the thread stacks
1273 * in the future we should be able to conservatively scan only:
1274 * *) the cpu registers
1275 * *) the unmanaged stack frames
1276 * *) the _last_ managed stack frame
1277 * *) pointers slots in managed frames
1279 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1283 unpin_objects_from_queue (SgenGrayQueue *queue)
1288 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1291 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1292 SGEN_UNPIN_OBJECT (addr);
1297 CopyOrMarkObjectFunc func;
1299 } UserCopyOrMarkData;
1302 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1304 UserCopyOrMarkData *data = gc_data;
1306 data->func (obj, data->queue);
1310 * The memory area from start_root to end_root contains pointers to objects.
1311 * Their position is precisely described by @desc (this means that the pointer
1312 * can be either NULL or the pointer to the start of an object).
1313 * This functions copies them to to_space updates them.
1315 * This function is not thread-safe!
1318 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1320 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1321 SgenGrayQueue *queue = ctx.queue;
1323 switch (desc & ROOT_DESC_TYPE_MASK) {
1324 case ROOT_DESC_BITMAP:
1325 desc >>= ROOT_DESC_TYPE_SHIFT;
1327 if ((desc & 1) && *start_root) {
1328 copy_func (start_root, queue);
1329 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1335 case ROOT_DESC_COMPLEX: {
1336 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1337 gsize bwords = (*bitmap_data) - 1;
1338 void **start_run = start_root;
1340 while (bwords-- > 0) {
1341 gsize bmap = *bitmap_data++;
1342 void **objptr = start_run;
1344 if ((bmap & 1) && *objptr) {
1345 copy_func (objptr, queue);
1346 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1351 start_run += GC_BITS_PER_WORD;
1355 case ROOT_DESC_USER: {
1356 UserCopyOrMarkData data = { copy_func, queue };
1357 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1358 marker (start_root, single_arg_user_copy_or_mark, &data);
1361 case ROOT_DESC_RUN_LEN:
1362 g_assert_not_reached ();
1364 g_assert_not_reached ();
1369 reset_heap_boundaries (void)
1371 lowest_heap_address = ~(mword)0;
1372 highest_heap_address = 0;
1376 sgen_update_heap_boundaries (mword low, mword high)
1381 old = lowest_heap_address;
1384 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1387 old = highest_heap_address;
1390 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1394 * Allocate and setup the data structures needed to be able to allocate objects
1395 * in the nursery. The nursery is stored in nursery_section.
1398 alloc_nursery (void)
1400 GCMemSection *section;
1405 if (nursery_section)
1407 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1408 /* later we will alloc a larger area for the nursery but only activate
1409 * what we need. The rest will be used as expansion if we have too many pinned
1410 * objects in the existing nursery.
1412 /* FIXME: handle OOM */
1413 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1415 alloc_size = sgen_nursery_size;
1417 /* If there isn't enough space even for the nursery we should simply abort. */
1418 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1420 #ifdef SGEN_ALIGN_NURSERY
1421 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1423 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1425 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1426 SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)mono_gc_get_heap_size ());
1427 section->data = section->next_data = data;
1428 section->size = alloc_size;
1429 section->end_data = data + sgen_nursery_size;
1430 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1431 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1432 section->num_scan_start = scan_starts;
1434 nursery_section = section;
1436 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1440 mono_gc_get_nursery (int *shift_bits, size_t *size)
1442 *size = sgen_nursery_size;
1443 #ifdef SGEN_ALIGN_NURSERY
1444 *shift_bits = DEFAULT_NURSERY_BITS;
1448 return sgen_get_nursery_start ();
1452 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1454 SgenThreadInfo *info = mono_thread_info_current ();
1456 /* Could be called from sgen_thread_unregister () with a NULL info */
1459 info->stopped_domain = domain;
1464 mono_gc_precise_stack_mark_enabled (void)
1466 return !conservative_stack_mark;
1470 mono_gc_get_logfile (void)
1472 return gc_debug_file;
1476 report_finalizer_roots_list (FinalizeReadyEntry *list)
1478 GCRootReport report;
1479 FinalizeReadyEntry *fin;
1482 for (fin = list; fin; fin = fin->next) {
1485 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1487 notify_gc_roots (&report);
1491 report_finalizer_roots (void)
1493 report_finalizer_roots_list (fin_ready_list);
1494 report_finalizer_roots_list (critical_fin_list);
1497 static GCRootReport *root_report;
1500 single_arg_report_root (void **obj, void *gc_data)
1503 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1507 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1509 switch (desc & ROOT_DESC_TYPE_MASK) {
1510 case ROOT_DESC_BITMAP:
1511 desc >>= ROOT_DESC_TYPE_SHIFT;
1513 if ((desc & 1) && *start_root) {
1514 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1520 case ROOT_DESC_COMPLEX: {
1521 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1522 gsize bwords = (*bitmap_data) - 1;
1523 void **start_run = start_root;
1525 while (bwords-- > 0) {
1526 gsize bmap = *bitmap_data++;
1527 void **objptr = start_run;
1529 if ((bmap & 1) && *objptr) {
1530 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1535 start_run += GC_BITS_PER_WORD;
1539 case ROOT_DESC_USER: {
1540 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1541 root_report = report;
1542 marker (start_root, single_arg_report_root, NULL);
1545 case ROOT_DESC_RUN_LEN:
1546 g_assert_not_reached ();
1548 g_assert_not_reached ();
1553 report_registered_roots_by_type (int root_type)
1555 GCRootReport report;
1559 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1560 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1561 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1562 } SGEN_HASH_TABLE_FOREACH_END;
1563 notify_gc_roots (&report);
1567 report_registered_roots (void)
1569 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1570 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1574 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1576 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1577 SgenGrayQueue *queue = ctx.queue;
1578 FinalizeReadyEntry *fin;
1580 for (fin = list; fin; fin = fin->next) {
1583 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1584 copy_func (&fin->object, queue);
1589 generation_name (int generation)
1591 switch (generation) {
1592 case GENERATION_NURSERY: return "nursery";
1593 case GENERATION_OLD: return "old";
1594 default: g_assert_not_reached ();
1599 sgen_generation_name (int generation)
1601 return generation_name (generation);
1604 SgenObjectOperations *
1605 sgen_get_current_object_ops (void){
1606 return ¤t_object_ops;
1611 finish_gray_stack (int generation, GrayQueue *queue)
1615 int done_with_ephemerons, ephemeron_rounds = 0;
1616 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1617 ScanObjectFunc scan_func = current_object_ops.scan_object;
1618 ScanCopyContext ctx = { scan_func, copy_func, queue };
1619 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1620 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1623 * We copied all the reachable objects. Now it's the time to copy
1624 * the objects that were not referenced by the roots, but by the copied objects.
1625 * we built a stack of objects pointed to by gray_start: they are
1626 * additional roots and we may add more items as we go.
1627 * We loop until gray_start == gray_objects which means no more objects have
1628 * been added. Note this is iterative: no recursion is involved.
1629 * We need to walk the LO list as well in search of marked big objects
1630 * (use a flag since this is needed only on major collections). We need to loop
1631 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1632 * To achieve better cache locality and cache usage, we drain the gray stack
1633 * frequently, after each object is copied, and just finish the work here.
1635 sgen_drain_gray_stack (-1, ctx);
1637 SGEN_LOG (2, "%s generation done", generation_name (generation));
1640 Reset bridge data, we might have lingering data from a previous collection if this is a major
1641 collection trigged by minor overflow.
1643 We must reset the gathered bridges since their original block might be evacuated due to major
1644 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1646 if (sgen_need_bridge_processing ())
1647 sgen_bridge_reset_data ();
1650 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1651 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1652 * objects that are in fact reachable.
1654 done_with_ephemerons = 0;
1656 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1657 sgen_drain_gray_stack (-1, ctx);
1659 } while (!done_with_ephemerons);
1661 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1663 if (sgen_need_bridge_processing ()) {
1664 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1665 sgen_drain_gray_stack (-1, ctx);
1666 sgen_collect_bridge_objects (generation, ctx);
1667 if (generation == GENERATION_OLD)
1668 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1671 Do the first bridge step here, as the collector liveness state will become useless after that.
1673 An important optimization is to only proccess the possibly dead part of the object graph and skip
1674 over all live objects as we transitively know everything they point must be alive too.
1676 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1678 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1679 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1682 sgen_bridge_processing_stw_step ();
1686 Make sure we drain the gray stack before processing disappearing links and finalizers.
1687 If we don't make sure it is empty we might wrongly see a live object as dead.
1689 sgen_drain_gray_stack (-1, ctx);
1692 We must clear weak links that don't track resurrection before processing object ready for
1693 finalization so they can be cleared before that.
1695 sgen_null_link_in_range (generation, TRUE, ctx);
1696 if (generation == GENERATION_OLD)
1697 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1700 /* walk the finalization queue and move also the objects that need to be
1701 * finalized: use the finalized objects as new roots so the objects they depend
1702 * on are also not reclaimed. As with the roots above, only objects in the nursery
1703 * are marked/copied.
1705 sgen_finalize_in_range (generation, ctx);
1706 if (generation == GENERATION_OLD)
1707 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1708 /* drain the new stack that might have been created */
1709 SGEN_LOG (6, "Precise scan of gray area post fin");
1710 sgen_drain_gray_stack (-1, ctx);
1713 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1715 done_with_ephemerons = 0;
1717 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1718 sgen_drain_gray_stack (-1, ctx);
1720 } while (!done_with_ephemerons);
1723 * Clear ephemeron pairs with unreachable keys.
1724 * We pass the copy func so we can figure out if an array was promoted or not.
1726 clear_unreachable_ephemerons (ctx);
1729 * We clear togglerefs only after all possible chances of revival are done.
1730 * This is semantically more inline with what users expect and it allows for
1731 * user finalizers to correctly interact with TR objects.
1733 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1736 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1739 * handle disappearing links
1740 * Note we do this after checking the finalization queue because if an object
1741 * survives (at least long enough to be finalized) we don't clear the link.
1742 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1743 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1746 g_assert (sgen_gray_object_queue_is_empty (queue));
1748 sgen_null_link_in_range (generation, FALSE, ctx);
1749 if (generation == GENERATION_OLD)
1750 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1751 if (sgen_gray_object_queue_is_empty (queue))
1753 sgen_drain_gray_stack (-1, ctx);
1756 g_assert (sgen_gray_object_queue_is_empty (queue));
1758 sgen_gray_object_queue_trim_free_list (queue);
1762 sgen_check_section_scan_starts (GCMemSection *section)
1765 for (i = 0; i < section->num_scan_start; ++i) {
1766 if (section->scan_starts [i]) {
1767 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1768 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1774 check_scan_starts (void)
1776 if (!do_scan_starts_check)
1778 sgen_check_section_scan_starts (nursery_section);
1779 major_collector.check_scan_starts ();
1783 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1787 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1788 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1789 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1790 } SGEN_HASH_TABLE_FOREACH_END;
1794 sgen_dump_occupied (char *start, char *end, char *section_start)
1796 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1800 sgen_dump_section (GCMemSection *section, const char *type)
1802 char *start = section->data;
1803 char *end = section->data + section->size;
1804 char *occ_start = NULL;
1806 char *old_start = NULL; /* just for debugging */
1808 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1810 while (start < end) {
1814 if (!*(void**)start) {
1816 sgen_dump_occupied (occ_start, start, section->data);
1819 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1822 g_assert (start < section->next_data);
1827 vt = (GCVTable*)LOAD_VTABLE (start);
1830 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1833 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1834 start - section->data,
1835 vt->klass->name_space, vt->klass->name,
1843 sgen_dump_occupied (occ_start, start, section->data);
1845 fprintf (heap_dump_file, "</section>\n");
1849 dump_object (MonoObject *obj, gboolean dump_location)
1851 static char class_name [1024];
1853 MonoClass *class = mono_object_class (obj);
1857 * Python's XML parser is too stupid to parse angle brackets
1858 * in strings, so we just ignore them;
1861 while (class->name [i] && j < sizeof (class_name) - 1) {
1862 if (!strchr ("<>\"", class->name [i]))
1863 class_name [j++] = class->name [i];
1866 g_assert (j < sizeof (class_name));
1869 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1870 class->name_space, class_name,
1871 safe_object_get_size (obj));
1872 if (dump_location) {
1873 const char *location;
1874 if (ptr_in_nursery (obj))
1875 location = "nursery";
1876 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1880 fprintf (heap_dump_file, " location=\"%s\"", location);
1882 fprintf (heap_dump_file, "/>\n");
1886 dump_heap (const char *type, int num, const char *reason)
1891 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1893 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1894 fprintf (heap_dump_file, ">\n");
1895 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1896 sgen_dump_internal_mem_usage (heap_dump_file);
1897 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1898 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1899 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1901 fprintf (heap_dump_file, "<pinned-objects>\n");
1902 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1903 dump_object (list->obj, TRUE);
1904 fprintf (heap_dump_file, "</pinned-objects>\n");
1906 sgen_dump_section (nursery_section, "nursery");
1908 major_collector.dump_heap (heap_dump_file);
1910 fprintf (heap_dump_file, "<los>\n");
1911 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1912 dump_object ((MonoObject*)bigobj->data, FALSE);
1913 fprintf (heap_dump_file, "</los>\n");
1915 fprintf (heap_dump_file, "</collection>\n");
1919 sgen_register_moved_object (void *obj, void *destination)
1921 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1923 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1924 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1925 moved_objects_idx = 0;
1927 moved_objects [moved_objects_idx++] = obj;
1928 moved_objects [moved_objects_idx++] = destination;
1934 static gboolean inited = FALSE;
1939 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1941 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1942 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1943 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1944 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1945 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1946 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1947 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1948 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1950 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1951 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1952 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1953 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1954 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1955 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1956 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1957 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1958 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1959 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1960 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1961 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1962 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1964 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1966 #ifdef HEAVY_STATISTICS
1967 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1968 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1969 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1970 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1971 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1972 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1973 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1974 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1975 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1977 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1978 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1980 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1981 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1982 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1983 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1985 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1986 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1988 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1990 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1991 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1992 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1993 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1995 sgen_nursery_allocator_init_heavy_stats ();
1996 sgen_alloc_init_heavy_stats ();
2004 reset_pinned_from_failed_allocation (void)
2006 bytes_pinned_from_failed_allocation = 0;
2010 sgen_set_pinned_from_failed_allocation (mword objsize)
2012 bytes_pinned_from_failed_allocation += objsize;
2016 sgen_collection_is_concurrent (void)
2018 switch (current_collection_generation) {
2019 case GENERATION_NURSERY:
2021 case GENERATION_OLD:
2022 return concurrent_collection_in_progress;
2024 g_error ("Invalid current generation %d", current_collection_generation);
2029 sgen_concurrent_collection_in_progress (void)
2031 return concurrent_collection_in_progress;
2038 } FinishRememberedSetScanJobData;
2041 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2043 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2045 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2046 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2051 CopyOrMarkObjectFunc copy_or_mark_func;
2052 ScanObjectFunc scan_func;
2056 } ScanFromRegisteredRootsJobData;
2059 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2061 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2062 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2063 sgen_workers_get_job_gray_queue (worker_data) };
2065 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2066 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2073 } ScanThreadDataJobData;
2076 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2078 ScanThreadDataJobData *job_data = job_data_untyped;
2080 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2081 sgen_workers_get_job_gray_queue (worker_data));
2082 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2086 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2088 FinalizeReadyEntry *list = job_data_untyped;
2089 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2091 scan_finalizer_entries (list, ctx);
2095 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2097 g_assert (concurrent_collection_in_progress);
2098 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2102 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2104 g_assert (concurrent_collection_in_progress);
2105 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2109 verify_scan_starts (char *start, char *end)
2113 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2114 char *addr = nursery_section->scan_starts [i];
2115 if (addr > start && addr < end)
2116 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2121 verify_nursery (void)
2123 char *start, *end, *cur, *hole_start;
2125 if (!do_verify_nursery)
2128 if (nursery_canaries_enabled ())
2129 SGEN_LOG (1, "Checking nursery canaries...");
2131 /*This cleans up unused fragments */
2132 sgen_nursery_allocator_prepare_for_pinning ();
2134 hole_start = start = cur = sgen_get_nursery_start ();
2135 end = sgen_get_nursery_end ();
2140 if (!*(void**)cur) {
2141 cur += sizeof (void*);
2145 if (object_is_forwarded (cur))
2146 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2147 else if (object_is_pinned (cur))
2148 SGEN_LOG (1, "PINNED OBJ %p", cur);
2150 ss = safe_object_get_size ((MonoObject*)cur);
2151 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2152 verify_scan_starts (cur, cur + size);
2153 if (do_dump_nursery_content) {
2154 if (cur > hole_start)
2155 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2156 SGEN_LOG (1, "OBJ [%p %p %d %d %s %d]", cur, cur + size, (int)size, (int)ss, sgen_safe_name ((MonoObject*)cur), (gpointer)LOAD_VTABLE (cur) == sgen_get_array_fill_vtable ());
2158 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2159 CHECK_CANARY_FOR_OBJECT (cur);
2160 CANARIFY_SIZE (size);
2168 * Checks that no objects in the nursery are fowarded or pinned. This
2169 * is a precondition to restarting the mutator while doing a
2170 * concurrent collection. Note that we don't clear fragments because
2171 * we depend on that having happened earlier.
2174 check_nursery_is_clean (void)
2176 char *start, *end, *cur;
2178 start = cur = sgen_get_nursery_start ();
2179 end = sgen_get_nursery_end ();
2184 if (!*(void**)cur) {
2185 cur += sizeof (void*);
2189 g_assert (!object_is_forwarded (cur));
2190 g_assert (!object_is_pinned (cur));
2192 ss = safe_object_get_size ((MonoObject*)cur);
2193 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2194 verify_scan_starts (cur, cur + size);
2201 init_gray_queue (void)
2203 if (sgen_collection_is_concurrent ())
2204 sgen_workers_init_distribute_gray_queue ();
2205 sgen_gray_object_queue_init (&gray_queue, NULL);
2209 * Perform a nursery collection.
2211 * Return whether any objects were late-pinned due to being out of memory.
2214 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2216 gboolean needs_major;
2217 size_t max_garbage_amount;
2219 FinishRememberedSetScanJobData *frssjd;
2220 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2221 ScanThreadDataJobData *stdjd;
2222 mword fragment_total;
2223 ScanCopyContext ctx;
2227 if (disable_minor_collections)
2230 TV_GETTIME (last_minor_collection_start_tv);
2231 atv = last_minor_collection_start_tv;
2233 MONO_GC_BEGIN (GENERATION_NURSERY);
2234 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2238 #ifndef DISABLE_PERFCOUNTERS
2239 mono_perfcounters->gc_collections0++;
2242 current_collection_generation = GENERATION_NURSERY;
2243 current_object_ops = sgen_minor_collector.serial_ops;
2245 reset_pinned_from_failed_allocation ();
2247 check_scan_starts ();
2249 sgen_nursery_alloc_prepare_for_minor ();
2253 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2254 /* FIXME: optimize later to use the higher address where an object can be present */
2255 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2257 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", gc_stats.minor_gc_count, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ()));
2258 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2259 g_assert (nursery_section->size >= max_garbage_amount);
2261 /* world must be stopped already */
2263 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2265 if (xdomain_checks) {
2266 sgen_clear_nursery_fragments ();
2267 sgen_check_for_xdomain_refs ();
2270 nursery_section->next_data = nursery_next;
2272 major_collector.start_nursery_collection ();
2274 sgen_memgov_minor_collection_start ();
2278 gc_stats.minor_gc_count ++;
2280 if (whole_heap_check_before_collection) {
2281 sgen_clear_nursery_fragments ();
2282 sgen_check_whole_heap (finish_up_concurrent_mark);
2284 if (consistency_check_at_minor_collection)
2285 sgen_check_consistency ();
2287 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2289 sgen_process_fin_stage_entries ();
2290 sgen_process_dislink_stage_entries ();
2292 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2294 /* pin from pinned handles */
2295 sgen_init_pinning ();
2296 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2297 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2298 /* pin cemented objects */
2299 sgen_pin_cemented_objects ();
2300 /* identify pinned objects */
2301 sgen_optimize_pin_queue ();
2302 sgen_pinning_setup_section (nursery_section);
2303 ctx.scan_func = NULL;
2304 ctx.copy_func = NULL;
2305 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2306 pin_objects_in_nursery (ctx);
2307 sgen_pinning_trim_queue_to_section (nursery_section);
2310 time_minor_pinning += TV_ELAPSED (btv, atv);
2311 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2312 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2314 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2316 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2317 frssjd->heap_start = sgen_get_nursery_start ();
2318 frssjd->heap_end = nursery_next;
2319 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2321 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2323 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2324 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2326 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2328 /* FIXME: why is this here? */
2329 ctx.scan_func = current_object_ops.scan_object;
2330 ctx.copy_func = NULL;
2331 ctx.queue = &gray_queue;
2332 sgen_drain_gray_stack (-1, ctx);
2334 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2335 report_registered_roots ();
2336 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2337 report_finalizer_roots ();
2339 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2341 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2343 /* registered roots, this includes static fields */
2344 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2345 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2346 scrrjd_normal->scan_func = current_object_ops.scan_object;
2347 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2348 scrrjd_normal->heap_end = nursery_next;
2349 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2350 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2352 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2353 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2354 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2355 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2356 scrrjd_wbarrier->heap_end = nursery_next;
2357 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2358 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2361 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2363 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2366 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2367 stdjd->heap_start = sgen_get_nursery_start ();
2368 stdjd->heap_end = nursery_next;
2369 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2372 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2375 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2377 g_assert (!sgen_collection_is_concurrent ());
2379 /* Scan the list of objects ready for finalization. If */
2380 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2381 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2383 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2385 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2387 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2388 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2390 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2393 * The (single-threaded) finalization code might have done
2394 * some copying/marking so we can only reset the GC thread's
2395 * worker data here instead of earlier when we joined the
2398 sgen_workers_reset_data ();
2400 if (objects_pinned) {
2401 sgen_optimize_pin_queue ();
2402 sgen_pinning_setup_section (nursery_section);
2405 /* walk the pin_queue, build up the fragment list of free memory, unmark
2406 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2409 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2410 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2411 if (!fragment_total)
2414 /* Clear TLABs for all threads */
2415 sgen_clear_tlabs ();
2417 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2419 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2420 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2422 if (consistency_check_at_minor_collection)
2423 sgen_check_major_refs ();
2425 major_collector.finish_nursery_collection ();
2427 TV_GETTIME (last_minor_collection_end_tv);
2428 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2431 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2433 /* prepare the pin queue for the next collection */
2434 sgen_finish_pinning ();
2435 if (fin_ready_list || critical_fin_list) {
2436 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2437 mono_gc_finalize_notify ();
2439 sgen_pin_stats_reset ();
2440 /* clear cemented hash */
2441 sgen_cement_clear_below_threshold ();
2443 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2445 remset.finish_minor_collection ();
2447 check_scan_starts ();
2449 binary_protocol_flush_buffers (FALSE);
2451 sgen_memgov_minor_collection_end ();
2453 /*objects are late pinned because of lack of memory, so a major is a good call*/
2454 needs_major = objects_pinned > 0;
2455 current_collection_generation = -1;
2458 MONO_GC_END (GENERATION_NURSERY);
2459 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
2461 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2462 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2468 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2471 * This is called on all objects in the nursery, including pinned ones, so we need
2472 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2474 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2478 scan_nursery_objects (ScanCopyContext ctx)
2480 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2481 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2485 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean start_concurrent_mark, gboolean finish_up_concurrent_mark, gboolean scan_mod_union, gboolean scan_whole_nursery)
2490 /* FIXME: only use these values for the precise scan
2491 * note that to_space pointers should be excluded anyway...
2493 char *heap_start = NULL;
2494 char *heap_end = (char*)-1;
2495 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2496 GCRootReport root_report = { 0 };
2497 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2498 ScanThreadDataJobData *stdjd;
2499 ScanCopyContext ctx;
2501 if (concurrent_collection_in_progress) {
2502 /*This cleans up unused fragments */
2503 sgen_nursery_allocator_prepare_for_pinning ();
2505 if (do_concurrent_checks)
2506 check_nursery_is_clean ();
2508 /* The concurrent collector doesn't touch the nursery. */
2509 sgen_nursery_alloc_prepare_for_major ();
2516 /* Pinning depends on this */
2517 sgen_clear_nursery_fragments ();
2519 if (whole_heap_check_before_collection)
2520 sgen_check_whole_heap (finish_up_concurrent_mark);
2523 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2525 if (!sgen_collection_is_concurrent ())
2526 nursery_section->next_data = sgen_get_nursery_end ();
2527 /* we should also coalesce scanning from sections close to each other
2528 * and deal with pointers outside of the sections later.
2532 *major_collector.have_swept = FALSE;
2534 if (xdomain_checks) {
2535 sgen_clear_nursery_fragments ();
2536 sgen_check_for_xdomain_refs ();
2539 if (!concurrent_collection_in_progress) {
2540 /* Remsets are not useful for a major collection */
2541 remset.prepare_for_major_collection ();
2544 sgen_process_fin_stage_entries ();
2545 sgen_process_dislink_stage_entries ();
2548 sgen_init_pinning ();
2549 SGEN_LOG (6, "Collecting pinned addresses");
2550 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2552 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2553 if (major_collector.is_concurrent) {
2555 * The concurrent major collector cannot evict
2556 * yet, so we need to pin cemented objects to
2557 * not break some asserts.
2559 * FIXME: We could evict now!
2561 sgen_pin_cemented_objects ();
2564 if (!concurrent_collection_in_progress)
2565 sgen_cement_reset ();
2568 sgen_optimize_pin_queue ();
2571 * pin_queue now contains all candidate pointers, sorted and
2572 * uniqued. We must do two passes now to figure out which
2573 * objects are pinned.
2575 * The first is to find within the pin_queue the area for each
2576 * section. This requires that the pin_queue be sorted. We
2577 * also process the LOS objects and pinned chunks here.
2579 * The second, destructive, pass is to reduce the section
2580 * areas to pointers to the actually pinned objects.
2582 SGEN_LOG (6, "Pinning from sections");
2583 /* first pass for the sections */
2584 sgen_find_section_pin_queue_start_end (nursery_section);
2585 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2586 /* identify possible pointers to the insize of large objects */
2587 SGEN_LOG (6, "Pinning from large objects");
2588 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2590 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2591 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2593 #ifdef ENABLE_DTRACE
2594 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2595 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2596 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2600 if (sgen_los_object_is_pinned (bigobj->data)) {
2601 g_assert (finish_up_concurrent_mark);
2604 sgen_los_pin_object (bigobj->data);
2605 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2606 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2607 if (G_UNLIKELY (do_pin_stats))
2608 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2609 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data, safe_name (bigobj->data), (unsigned long)sgen_los_object_size (bigobj));
2612 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2616 notify_gc_roots (&root_report);
2617 /* second pass for the sections */
2618 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2619 ctx.copy_func = NULL;
2620 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2623 * Concurrent mark never follows references into the nursery. In the start and
2624 * finish pauses we must scan live nursery objects, though.
2626 * In the finish pause we do this conservatively by scanning all nursery objects.
2627 * Previously we would only scan pinned objects here. We assumed that all objects
2628 * that were pinned during the nursery collection immediately preceding this finish
2629 * mark would be pinned again here. Due to the way we get the stack end for the GC
2630 * thread, however, that's not necessarily the case: we scan part of the stack used
2631 * by the GC itself, which changes constantly, so pinning isn't entirely
2634 * The split nursery also complicates things because non-pinned objects can survive
2635 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2637 * In the future we shouldn't do a preceding nursery collection at all and instead
2638 * do the finish pause with promotion from the nursery.
2640 * A further complication arises when we have late-pinned objects from the preceding
2641 * nursery collection. Those are the result of being out of memory when trying to
2642 * evacuate objects. They won't be found from the roots, so we just scan the whole
2645 * Non-concurrent mark evacuates from the nursery, so it's
2646 * sufficient to just scan pinned nursery objects.
2648 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2649 scan_nursery_objects (ctx);
2651 pin_objects_in_nursery (ctx);
2652 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2653 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2656 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2657 if (old_next_pin_slot)
2658 *old_next_pin_slot = sgen_get_pinned_count ();
2661 time_major_pinning += TV_ELAPSED (atv, btv);
2662 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2663 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2665 major_collector.init_to_space ();
2668 * The concurrent collector doesn't move objects, neither on
2669 * the major heap nor in the nursery, so we can mark even
2670 * before pinning has finished. For the non-concurrent
2671 * collector we start the workers after pinning.
2673 if (start_concurrent_mark) {
2674 sgen_workers_start_all_workers ();
2675 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2678 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2679 main_gc_thread = mono_native_thread_self ();
2682 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2683 report_registered_roots ();
2685 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2687 /* registered roots, this includes static fields */
2688 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2689 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2690 scrrjd_normal->scan_func = current_object_ops.scan_object;
2691 scrrjd_normal->heap_start = heap_start;
2692 scrrjd_normal->heap_end = heap_end;
2693 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2694 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2696 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2697 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2698 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2699 scrrjd_wbarrier->heap_start = heap_start;
2700 scrrjd_wbarrier->heap_end = heap_end;
2701 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2702 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2705 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2708 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2709 stdjd->heap_start = heap_start;
2710 stdjd->heap_end = heap_end;
2711 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2714 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2717 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2719 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2720 report_finalizer_roots ();
2722 /* scan the list of objects ready for finalization */
2723 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2724 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2726 if (scan_mod_union) {
2727 g_assert (finish_up_concurrent_mark);
2729 /* Mod union card table */
2730 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2731 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2735 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2736 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2739 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2743 major_finish_copy_or_mark (void)
2745 if (!concurrent_collection_in_progress)
2749 * Prepare the pin queue for the next collection. Since pinning runs on the worker
2750 * threads we must wait for the jobs to finish before we can reset it.
2752 sgen_workers_wait_for_jobs_finished ();
2753 sgen_finish_pinning ();
2755 sgen_pin_stats_reset ();
2757 if (do_concurrent_checks)
2758 check_nursery_is_clean ();
2762 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2764 MONO_GC_BEGIN (GENERATION_OLD);
2765 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2767 current_collection_generation = GENERATION_OLD;
2768 #ifndef DISABLE_PERFCOUNTERS
2769 mono_perfcounters->gc_collections1++;
2772 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2775 g_assert (major_collector.is_concurrent);
2776 concurrent_collection_in_progress = TRUE;
2778 sgen_cement_concurrent_start ();
2780 current_object_ops = major_collector.major_concurrent_ops;
2782 current_object_ops = major_collector.major_ops;
2785 reset_pinned_from_failed_allocation ();
2787 sgen_memgov_major_collection_start ();
2789 //count_ref_nonref_objs ();
2790 //consistency_check ();
2792 check_scan_starts ();
2795 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2796 gc_stats.major_gc_count ++;
2798 if (major_collector.start_major_collection)
2799 major_collector.start_major_collection ();
2801 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent, FALSE, FALSE, FALSE);
2802 major_finish_copy_or_mark ();
2806 wait_for_workers_to_finish (void)
2808 while (!sgen_workers_all_done ())
2813 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union, gboolean scan_whole_nursery)
2815 ScannedObjectCounts counts;
2816 LOSObject *bigobj, *prevbo;
2822 if (concurrent_collection_in_progress) {
2823 sgen_workers_signal_start_nursery_collection_and_wait ();
2825 current_object_ops = major_collector.major_concurrent_ops;
2827 major_copy_or_mark_from_roots (NULL, FALSE, TRUE, scan_mod_union, scan_whole_nursery);
2829 sgen_workers_signal_finish_nursery_collection ();
2831 major_finish_copy_or_mark ();
2832 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2834 sgen_workers_join ();
2836 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2838 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2839 main_gc_thread = NULL;
2842 if (do_concurrent_checks)
2843 check_nursery_is_clean ();
2845 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2846 current_object_ops = major_collector.major_ops;
2850 * The workers have stopped so we need to finish gray queue
2851 * work that might result from finalization in the main GC
2852 * thread. Redirection must therefore be turned off.
2854 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2855 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2857 /* all the objects in the heap */
2858 finish_gray_stack (GENERATION_OLD, &gray_queue);
2860 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2862 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2865 * The (single-threaded) finalization code might have done
2866 * some copying/marking so we can only reset the GC thread's
2867 * worker data here instead of earlier when we joined the
2870 sgen_workers_reset_data ();
2872 if (objects_pinned) {
2873 g_assert (!concurrent_collection_in_progress);
2876 * This is slow, but we just OOM'd.
2878 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2879 * queue is laid out at this point.
2881 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2883 * We need to reestablish all pinned nursery objects in the pin queue
2884 * because they're needed for fragment creation. Unpinning happens by
2885 * walking the whole queue, so it's not necessary to reestablish where major
2886 * heap block pins are - all we care is that they're still in there
2889 sgen_optimize_pin_queue ();
2890 sgen_find_section_pin_queue_start_end (nursery_section);
2894 reset_heap_boundaries ();
2895 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2897 if (!concurrent_collection_in_progress) {
2898 /* walk the pin_queue, build up the fragment list of free memory, unmark
2899 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2902 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2905 /* prepare the pin queue for the next collection */
2906 sgen_finish_pinning ();
2908 /* Clear TLABs for all threads */
2909 sgen_clear_tlabs ();
2911 sgen_pin_stats_reset ();
2914 if (concurrent_collection_in_progress)
2915 sgen_cement_concurrent_finish ();
2916 sgen_cement_clear_below_threshold ();
2918 if (check_mark_bits_after_major_collection)
2919 sgen_check_heap_marked (concurrent_collection_in_progress);
2922 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2925 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2927 /* sweep the big objects list */
2929 for (bigobj = los_object_list; bigobj;) {
2930 g_assert (!object_is_pinned (bigobj->data));
2931 if (sgen_los_object_is_pinned (bigobj->data)) {
2932 sgen_los_unpin_object (bigobj->data);
2933 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2936 /* not referenced anywhere, so we can free it */
2938 prevbo->next = bigobj->next;
2940 los_object_list = bigobj->next;
2942 bigobj = bigobj->next;
2943 sgen_los_free_object (to_free);
2947 bigobj = bigobj->next;
2951 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2956 time_major_los_sweep += TV_ELAPSED (atv, btv);
2958 major_collector.sweep ();
2960 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2963 time_major_sweep += TV_ELAPSED (btv, atv);
2966 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2968 if (fin_ready_list || critical_fin_list) {
2969 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2970 mono_gc_finalize_notify ();
2973 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2975 sgen_memgov_major_collection_end ();
2976 current_collection_generation = -1;
2978 memset (&counts, 0, sizeof (ScannedObjectCounts));
2979 major_collector.finish_major_collection (&counts);
2981 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2983 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2984 if (concurrent_collection_in_progress)
2985 concurrent_collection_in_progress = FALSE;
2987 check_scan_starts ();
2989 binary_protocol_flush_buffers (FALSE);
2991 //consistency_check ();
2993 MONO_GC_END (GENERATION_OLD);
2994 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2998 major_do_collection (const char *reason)
3000 TV_DECLARE (time_start);
3001 TV_DECLARE (time_end);
3002 size_t old_next_pin_slot;
3004 if (disable_major_collections)
3007 if (major_collector.get_and_reset_num_major_objects_marked) {
3008 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
3009 g_assert (!num_marked);
3012 /* world must be stopped already */
3013 TV_GETTIME (time_start);
3015 major_start_collection (FALSE, &old_next_pin_slot);
3016 major_finish_collection (reason, old_next_pin_slot, FALSE, FALSE);
3018 TV_GETTIME (time_end);
3019 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3021 /* FIXME: also report this to the user, preferably in gc-end. */
3022 if (major_collector.get_and_reset_num_major_objects_marked)
3023 major_collector.get_and_reset_num_major_objects_marked ();
3025 return bytes_pinned_from_failed_allocation > 0;
3029 major_start_concurrent_collection (const char *reason)
3031 TV_DECLARE (time_start);
3032 TV_DECLARE (time_end);
3033 long long num_objects_marked;
3035 if (disable_major_collections)
3038 TV_GETTIME (time_start);
3039 SGEN_TV_GETTIME (time_major_conc_collection_start);
3041 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3042 g_assert (num_objects_marked == 0);
3044 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3045 binary_protocol_concurrent_start ();
3047 // FIXME: store reason and pass it when finishing
3048 major_start_collection (TRUE, NULL);
3050 gray_queue_redirect (&gray_queue);
3052 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3053 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3055 TV_GETTIME (time_end);
3056 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3058 current_collection_generation = -1;
3062 * Returns whether the major collection has finished.
3065 major_should_finish_concurrent_collection (void)
3067 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
3068 return sgen_workers_all_done ();
3072 major_update_concurrent_collection (void)
3074 TV_DECLARE (total_start);
3075 TV_DECLARE (total_end);
3077 TV_GETTIME (total_start);
3079 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3080 binary_protocol_concurrent_update ();
3082 major_collector.update_cardtable_mod_union ();
3083 sgen_los_update_cardtable_mod_union ();
3085 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3087 TV_GETTIME (total_end);
3088 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3092 major_finish_concurrent_collection (void)
3094 TV_DECLARE (total_start);
3095 TV_DECLARE (total_end);
3096 gboolean late_pinned;
3097 SgenGrayQueue unpin_queue;
3098 memset (&unpin_queue, 0, sizeof (unpin_queue));
3100 TV_GETTIME (total_start);
3102 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3103 binary_protocol_concurrent_finish ();
3106 * The major collector can add global remsets which are processed in the finishing
3107 * nursery collection, below. That implies that the workers must have finished
3108 * marking before the nursery collection is allowed to run, otherwise we might miss
3111 wait_for_workers_to_finish ();
3113 SGEN_TV_GETTIME (time_major_conc_collection_end);
3114 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3116 major_collector.update_cardtable_mod_union ();
3117 sgen_los_update_cardtable_mod_union ();
3119 late_pinned = collect_nursery (&unpin_queue, TRUE);
3121 if (mod_union_consistency_check)
3122 sgen_check_mod_union_consistency ();
3124 current_collection_generation = GENERATION_OLD;
3125 major_finish_collection ("finishing", -1, TRUE, late_pinned);
3127 if (whole_heap_check_before_collection)
3128 sgen_check_whole_heap (FALSE);
3130 unpin_objects_from_queue (&unpin_queue);
3131 sgen_gray_object_queue_deinit (&unpin_queue);
3133 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3135 TV_GETTIME (total_end);
3136 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3138 current_collection_generation = -1;
3142 * Ensure an allocation request for @size will succeed by freeing enough memory.
3144 * LOCKING: The GC lock MUST be held.
3147 sgen_ensure_free_space (size_t size)
3149 int generation_to_collect = -1;
3150 const char *reason = NULL;
3153 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3154 if (sgen_need_major_collection (size)) {
3155 reason = "LOS overflow";
3156 generation_to_collect = GENERATION_OLD;
3159 if (degraded_mode) {
3160 if (sgen_need_major_collection (size)) {
3161 reason = "Degraded mode overflow";
3162 generation_to_collect = GENERATION_OLD;
3164 } else if (sgen_need_major_collection (size)) {
3165 reason = "Minor allowance";
3166 generation_to_collect = GENERATION_OLD;
3168 generation_to_collect = GENERATION_NURSERY;
3169 reason = "Nursery full";
3173 if (generation_to_collect == -1) {
3174 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3175 generation_to_collect = GENERATION_OLD;
3176 reason = "Finish concurrent collection";
3180 if (generation_to_collect == -1)
3182 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3186 * LOCKING: Assumes the GC lock is held.
3189 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3191 TV_DECLARE (gc_start);
3192 TV_DECLARE (gc_end);
3193 TV_DECLARE (gc_total_start);
3194 TV_DECLARE (gc_total_end);
3195 GGTimingInfo infos [2];
3196 int overflow_generation_to_collect = -1;
3197 int oldest_generation_collected = generation_to_collect;
3198 const char *overflow_reason = NULL;
3200 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3202 binary_protocol_collection_force (generation_to_collect);
3204 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3206 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3208 TV_GETTIME (gc_start);
3210 sgen_stop_world (generation_to_collect);
3212 TV_GETTIME (gc_total_start);
3214 if (concurrent_collection_in_progress) {
3216 * We update the concurrent collection. If it finished, we're done. If
3217 * not, and we've been asked to do a nursery collection, we do that.
3219 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3222 major_finish_concurrent_collection ();
3223 oldest_generation_collected = GENERATION_OLD;
3225 sgen_workers_signal_start_nursery_collection_and_wait ();
3227 major_update_concurrent_collection ();
3228 if (generation_to_collect == GENERATION_NURSERY)
3229 collect_nursery (NULL, FALSE);
3231 sgen_workers_signal_finish_nursery_collection ();
3238 * If we've been asked to do a major collection, and the major collector wants to
3239 * run synchronously (to evacuate), we set the flag to do that.
3241 if (generation_to_collect == GENERATION_OLD &&
3242 allow_synchronous_major &&
3243 major_collector.want_synchronous_collection &&
3244 *major_collector.want_synchronous_collection) {
3245 wait_to_finish = TRUE;
3248 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3251 * There's no concurrent collection in progress. Collect the generation we're asked
3252 * to collect. If the major collector is concurrent and we're not forced to wait,
3253 * start a concurrent collection.
3255 // FIXME: extract overflow reason
3256 if (generation_to_collect == GENERATION_NURSERY) {
3257 if (collect_nursery (NULL, FALSE)) {
3258 overflow_generation_to_collect = GENERATION_OLD;
3259 overflow_reason = "Minor overflow";
3262 if (major_collector.is_concurrent && !wait_to_finish) {
3263 collect_nursery (NULL, FALSE);
3264 major_start_concurrent_collection (reason);
3265 // FIXME: set infos[0] properly
3269 if (major_do_collection (reason)) {
3270 overflow_generation_to_collect = GENERATION_NURSERY;
3271 overflow_reason = "Excessive pinning";
3275 TV_GETTIME (gc_end);
3277 memset (infos, 0, sizeof (infos));
3278 infos [0].generation = generation_to_collect;
3279 infos [0].reason = reason;
3280 infos [0].is_overflow = FALSE;
3281 infos [1].generation = -1;
3282 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3284 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3286 if (overflow_generation_to_collect != -1) {
3288 * We need to do an overflow collection, either because we ran out of memory
3289 * or the nursery is fully pinned.
3292 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3293 infos [1].generation = overflow_generation_to_collect;
3294 infos [1].reason = overflow_reason;
3295 infos [1].is_overflow = TRUE;
3296 infos [1].total_time = gc_end;
3298 if (overflow_generation_to_collect == GENERATION_NURSERY)
3299 collect_nursery (NULL, FALSE);
3301 major_do_collection (overflow_reason);
3303 TV_GETTIME (gc_end);
3304 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3306 /* keep events symmetric */
3307 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3309 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3312 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3314 /* this also sets the proper pointers for the next allocation */
3315 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3316 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3317 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3318 sgen_dump_pin_queue ();
3323 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3325 TV_GETTIME (gc_total_end);
3326 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3328 sgen_restart_world (oldest_generation_collected, infos);
3330 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3334 * ######################################################################
3335 * ######## Memory allocation from the OS
3336 * ######################################################################
3337 * This section of code deals with getting memory from the OS and
3338 * allocating memory for GC-internal data structures.
3339 * Internal memory can be handled with a freelist for small objects.
3345 G_GNUC_UNUSED static void
3346 report_internal_mem_usage (void)
3348 printf ("Internal memory usage:\n");
3349 sgen_report_internal_mem_usage ();
3350 printf ("Pinned memory usage:\n");
3351 major_collector.report_pinned_memory_usage ();
3355 * ######################################################################
3356 * ######## Finalization support
3357 * ######################################################################
3360 static inline gboolean
3361 sgen_major_is_object_alive (void *object)
3365 /* Oldgen objects can be pinned and forwarded too */
3366 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3370 * FIXME: major_collector.is_object_live() also calculates the
3371 * size. Avoid the double calculation.
3373 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3374 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3375 return sgen_los_object_is_pinned (object);
3377 return major_collector.is_object_live (object);
3381 * If the object has been forwarded it means it's still referenced from a root.
3382 * If it is pinned it's still alive as well.
3383 * A LOS object is only alive if we have pinned it.
3384 * Return TRUE if @obj is ready to be finalized.
3386 static inline gboolean
3387 sgen_is_object_alive (void *object)
3389 if (ptr_in_nursery (object))
3390 return sgen_nursery_is_object_alive (object);
3392 return sgen_major_is_object_alive (object);
3396 * This function returns true if @object is either alive or it belongs to the old gen
3397 * and we're currently doing a minor collection.
3400 sgen_is_object_alive_for_current_gen (char *object)
3402 if (ptr_in_nursery (object))
3403 return sgen_nursery_is_object_alive (object);
3405 if (current_collection_generation == GENERATION_NURSERY)
3408 return sgen_major_is_object_alive (object);
3412 * This function returns true if @object is either alive and belongs to the
3413 * current collection - major collections are full heap, so old gen objects
3414 * are never alive during a minor collection.
3417 sgen_is_object_alive_and_on_current_collection (char *object)
3419 if (ptr_in_nursery (object))
3420 return sgen_nursery_is_object_alive (object);
3422 if (current_collection_generation == GENERATION_NURSERY)
3425 return sgen_major_is_object_alive (object);
3430 sgen_gc_is_object_ready_for_finalization (void *object)
3432 return !sgen_is_object_alive (object);
3436 has_critical_finalizer (MonoObject *obj)
3440 if (!mono_defaults.critical_finalizer_object)
3443 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3445 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3449 is_finalization_aware (MonoObject *obj)
3451 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3452 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3456 sgen_queue_finalization_entry (MonoObject *obj)
3458 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3459 gboolean critical = has_critical_finalizer (obj);
3460 entry->object = obj;
3462 entry->next = critical_fin_list;
3463 critical_fin_list = entry;
3465 entry->next = fin_ready_list;
3466 fin_ready_list = entry;
3469 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3470 fin_callbacks.object_queued_for_finalization (obj);
3472 #ifdef ENABLE_DTRACE
3473 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3474 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3475 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3476 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3477 vt->klass->name_space, vt->klass->name, gen, critical);
3483 sgen_object_is_live (void *obj)
3485 return sgen_is_object_alive_and_on_current_collection (obj);
3488 /* LOCKING: requires that the GC lock is held */
3490 null_ephemerons_for_domain (MonoDomain *domain)
3492 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3495 MonoObject *object = (MonoObject*)current->array;
3498 SGEN_ASSERT (0, object->vtable, "Can't have objects without vtables.");
3500 if (object && object->vtable->domain == domain) {
3501 EphemeronLinkNode *tmp = current;
3504 prev->next = current->next;
3506 ephemeron_list = current->next;
3508 current = current->next;
3509 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3512 current = current->next;
3517 /* LOCKING: requires that the GC lock is held */
3519 clear_unreachable_ephemerons (ScanCopyContext ctx)
3521 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3522 GrayQueue *queue = ctx.queue;
3523 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3525 Ephemeron *cur, *array_end;
3529 char *object = current->array;
3531 if (!sgen_is_object_alive_for_current_gen (object)) {
3532 EphemeronLinkNode *tmp = current;
3534 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3537 prev->next = current->next;
3539 ephemeron_list = current->next;
3541 current = current->next;
3542 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3547 copy_func ((void**)&object, queue);
3548 current->array = object;
3550 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3552 array = (MonoArray*)object;
3553 cur = mono_array_addr (array, Ephemeron, 0);
3554 array_end = cur + mono_array_length_fast (array);
3555 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3557 for (; cur < array_end; ++cur) {
3558 char *key = (char*)cur->key;
3560 if (!key || key == tombstone)
3563 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3564 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3565 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3567 if (!sgen_is_object_alive_for_current_gen (key)) {
3568 cur->key = tombstone;
3574 current = current->next;
3579 LOCKING: requires that the GC lock is held
3581 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3584 mark_ephemerons_in_range (ScanCopyContext ctx)
3586 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3587 GrayQueue *queue = ctx.queue;
3588 int nothing_marked = 1;
3589 EphemeronLinkNode *current = ephemeron_list;
3591 Ephemeron *cur, *array_end;
3594 for (current = ephemeron_list; current; current = current->next) {
3595 char *object = current->array;
3596 SGEN_LOG (5, "Ephemeron array at %p", object);
3598 /*It has to be alive*/
3599 if (!sgen_is_object_alive_for_current_gen (object)) {
3600 SGEN_LOG (5, "\tnot reachable");
3604 copy_func ((void**)&object, queue);
3606 array = (MonoArray*)object;
3607 cur = mono_array_addr (array, Ephemeron, 0);
3608 array_end = cur + mono_array_length_fast (array);
3609 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3611 for (; cur < array_end; ++cur) {
3612 char *key = cur->key;
3614 if (!key || key == tombstone)
3617 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3618 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3619 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3621 if (sgen_is_object_alive_for_current_gen (key)) {
3622 char *value = cur->value;
3624 copy_func ((void**)&cur->key, queue);
3626 if (!sgen_is_object_alive_for_current_gen (value))
3628 copy_func ((void**)&cur->value, queue);
3634 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3635 return nothing_marked;
3639 mono_gc_invoke_finalizers (void)
3641 FinalizeReadyEntry *entry = NULL;
3642 gboolean entry_is_critical = FALSE;
3645 /* FIXME: batch to reduce lock contention */
3646 while (fin_ready_list || critical_fin_list) {
3650 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3652 /* We have finalized entry in the last
3653 interation, now we need to remove it from
3656 *list = entry->next;
3658 FinalizeReadyEntry *e = *list;
3659 while (e->next != entry)
3661 e->next = entry->next;
3663 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3667 /* Now look for the first non-null entry. */
3668 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3671 entry_is_critical = FALSE;
3673 entry_is_critical = TRUE;
3674 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3679 g_assert (entry->object);
3680 num_ready_finalizers--;
3681 obj = entry->object;
3682 entry->object = NULL;
3683 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3691 g_assert (entry->object == NULL);
3693 /* the object is on the stack so it is pinned */
3694 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3695 if (!do_not_finalize)
3696 mono_gc_run_finalize (obj, NULL);
3703 mono_gc_pending_finalizers (void)
3705 return fin_ready_list || critical_fin_list;
3709 * ######################################################################
3710 * ######## registered roots support
3711 * ######################################################################
3715 * We do not coalesce roots.
3718 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3720 RootRecord new_root;
3723 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3724 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3725 /* we allow changing the size and the descriptor (for thread statics etc) */
3727 size_t old_size = root->end_root - start;
3728 root->end_root = start + size;
3729 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3730 ((root->root_desc == 0) && (descr == NULL)));
3731 root->root_desc = (mword)descr;
3733 roots_size -= old_size;
3739 new_root.end_root = start + size;
3740 new_root.root_desc = (mword)descr;
3742 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3745 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);
3752 mono_gc_register_root (char *start, size_t size, void *descr)
3754 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3758 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3760 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3764 mono_gc_deregister_root (char* addr)
3770 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3771 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3772 roots_size -= (root.end_root - addr);
3778 * ######################################################################
3779 * ######## Thread handling (stop/start code)
3780 * ######################################################################
3783 unsigned int sgen_global_stop_count = 0;
3786 sgen_get_current_collection_generation (void)
3788 return current_collection_generation;
3792 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3794 gc_callbacks = *callbacks;
3798 mono_gc_get_gc_callbacks ()
3800 return &gc_callbacks;
3803 /* Variables holding start/end nursery so it won't have to be passed at every call */
3804 static void *scan_area_arg_start, *scan_area_arg_end;
3807 mono_gc_conservatively_scan_area (void *start, void *end)
3809 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3813 mono_gc_scan_object (void *obj, void *gc_data)
3815 UserCopyOrMarkData *data = gc_data;
3816 current_object_ops.copy_or_mark_object (&obj, data->queue);
3821 * Mark from thread stacks and registers.
3824 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3826 SgenThreadInfo *info;
3828 scan_area_arg_start = start_nursery;
3829 scan_area_arg_end = end_nursery;
3831 FOREACH_THREAD (info) {
3833 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);
3836 if (info->gc_disabled) {
3837 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);
3840 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3841 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));
3844 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 ());
3845 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3846 UserCopyOrMarkData data = { NULL, queue };
3847 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3848 } else if (!precise) {
3849 if (!conservative_stack_mark) {
3850 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3851 conservative_stack_mark = TRUE;
3853 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3858 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3859 start_nursery, end_nursery, PIN_TYPE_STACK);
3861 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3862 start_nursery, end_nursery, PIN_TYPE_STACK);
3865 } END_FOREACH_THREAD
3869 ptr_on_stack (void *ptr)
3871 gpointer stack_start = &stack_start;
3872 SgenThreadInfo *info = mono_thread_info_current ();
3874 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3880 sgen_thread_register (SgenThreadInfo* info, void *addr)
3883 guint8 *staddr = NULL;
3885 #ifndef HAVE_KW_THREAD
3886 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3888 g_assert (!mono_native_tls_get_value (thread_info_key));
3889 mono_native_tls_set_value (thread_info_key, info);
3891 sgen_thread_info = info;
3894 #ifdef SGEN_POSIX_STW
3895 info->stop_count = -1;
3899 info->stack_start = NULL;
3900 info->stopped_ip = NULL;
3901 info->stopped_domain = NULL;
3903 memset (&info->ctx, 0, sizeof (MonoContext));
3905 memset (&info->regs, 0, sizeof (info->regs));
3908 sgen_init_tlab_info (info);
3910 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3912 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3913 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3916 info->stack_start_limit = staddr;
3918 info->stack_end = staddr + stsize;
3920 gsize stack_bottom = (gsize)addr;
3921 stack_bottom += 4095;
3922 stack_bottom &= ~4095;
3923 info->stack_end = (char*)stack_bottom;
3926 #ifdef HAVE_KW_THREAD
3927 stack_end = info->stack_end;
3930 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3932 if (gc_callbacks.thread_attach_func)
3933 info->runtime_data = gc_callbacks.thread_attach_func ();
3938 sgen_thread_detach (SgenThreadInfo *p)
3940 /* If a delegate is passed to native code and invoked on a thread we dont
3941 * know about, the jit will register it with mono_jit_thread_attach, but
3942 * we have no way of knowing when that thread goes away. SGen has a TSD
3943 * so we assume that if the domain is still registered, we can detach
3946 if (mono_domain_get ())
3947 mono_thread_detach_internal (mono_thread_internal_current ());
3951 sgen_thread_unregister (SgenThreadInfo *p)
3953 MonoNativeThreadId tid;
3955 tid = mono_thread_info_get_tid (p);
3956 binary_protocol_thread_unregister ((gpointer)tid);
3957 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3959 #ifndef HAVE_KW_THREAD
3960 mono_native_tls_set_value (thread_info_key, NULL);
3962 sgen_thread_info = NULL;
3965 if (p->info.runtime_thread)
3966 mono_threads_add_joinable_thread ((gpointer)tid);
3968 if (gc_callbacks.thread_detach_func) {
3969 gc_callbacks.thread_detach_func (p->runtime_data);
3970 p->runtime_data = NULL;
3976 sgen_thread_attach (SgenThreadInfo *info)
3979 /*this is odd, can we get attached before the gc is inited?*/
3983 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3984 info->runtime_data = gc_callbacks.thread_attach_func ();
3987 mono_gc_register_thread (void *baseptr)
3989 return mono_thread_info_attach (baseptr) != NULL;
3993 * mono_gc_set_stack_end:
3995 * Set the end of the current threads stack to STACK_END. The stack space between
3996 * STACK_END and the real end of the threads stack will not be scanned during collections.
3999 mono_gc_set_stack_end (void *stack_end)
4001 SgenThreadInfo *info;
4004 info = mono_thread_info_current ();
4006 g_assert (stack_end < info->stack_end);
4007 info->stack_end = stack_end;
4012 #if USE_PTHREAD_INTERCEPT
4016 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4018 return pthread_create (new_thread, attr, start_routine, arg);
4022 mono_gc_pthread_join (pthread_t thread, void **retval)
4024 return pthread_join (thread, retval);
4028 mono_gc_pthread_detach (pthread_t thread)
4030 return pthread_detach (thread);
4034 mono_gc_pthread_exit (void *retval)
4036 mono_thread_info_detach ();
4037 pthread_exit (retval);
4038 g_assert_not_reached ();
4041 #endif /* USE_PTHREAD_INTERCEPT */
4044 * ######################################################################
4045 * ######## Write barriers
4046 * ######################################################################
4050 * Note: the write barriers first do the needed GC work and then do the actual store:
4051 * this way the value is visible to the conservative GC scan after the write barrier
4052 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4053 * the conservative scan, otherwise by the remembered set scan.
4056 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4058 HEAVY_STAT (++stat_wbarrier_set_field);
4059 if (ptr_in_nursery (field_ptr)) {
4060 *(void**)field_ptr = value;
4063 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4065 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4067 remset.wbarrier_set_field (obj, field_ptr, value);
4071 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4073 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4074 if (ptr_in_nursery (slot_ptr)) {
4075 *(void**)slot_ptr = value;
4078 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4080 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4082 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4086 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4088 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4089 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4090 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4091 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4095 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4096 if (binary_protocol_is_heavy_enabled ()) {
4098 for (i = 0; i < count; ++i) {
4099 gpointer dest = (gpointer*)dest_ptr + i;
4100 gpointer obj = *((gpointer*)src_ptr + i);
4102 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4107 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4110 static char *found_obj;
4113 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4115 char *ptr = user_data;
4117 if (ptr >= obj && ptr < obj + size) {
4118 g_assert (!found_obj);
4123 /* for use in the debugger */
4124 char* find_object_for_ptr (char *ptr);
4126 find_object_for_ptr (char *ptr)
4128 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4130 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4131 find_object_for_ptr_callback, ptr, TRUE);
4137 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4142 * Very inefficient, but this is debugging code, supposed to
4143 * be called from gdb, so we don't care.
4146 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4151 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4155 HEAVY_STAT (++stat_wbarrier_generic_store);
4157 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4158 /* FIXME: ptr_in_heap must be called with the GC lock held */
4159 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4160 char *start = find_object_for_ptr (ptr);
4161 MonoObject *value = *(MonoObject**)ptr;
4165 MonoObject *obj = (MonoObject*)start;
4166 if (obj->vtable->domain != value->vtable->domain)
4167 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4173 obj = *(gpointer*)ptr;
4175 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4177 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4178 SGEN_LOG (8, "Skipping remset at %p", ptr);
4183 * We need to record old->old pointer locations for the
4184 * concurrent collector.
4186 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4187 SGEN_LOG (8, "Skipping remset at %p", ptr);
4191 SGEN_LOG (8, "Adding remset at %p", ptr);
4193 remset.wbarrier_generic_nostore (ptr);
4197 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4199 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4200 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4201 if (ptr_in_nursery (value))
4202 mono_gc_wbarrier_generic_nostore (ptr);
4203 sgen_dummy_use (value);
4206 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4207 * as an atomic operation with release semantics.
4210 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4212 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4214 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4216 InterlockedWritePointer (ptr, value);
4218 if (ptr_in_nursery (value))
4219 mono_gc_wbarrier_generic_nostore (ptr);
4221 sgen_dummy_use (value);
4224 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4226 mword *dest = _dest;
4231 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4233 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4236 size -= SIZEOF_VOID_P;
4241 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4243 #define HANDLE_PTR(ptr,obj) do { \
4244 gpointer o = *(gpointer*)(ptr); \
4246 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4247 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4252 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4254 #define SCAN_OBJECT_NOVTABLE
4255 #include "sgen-scan-object.h"
4260 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4262 HEAVY_STAT (++stat_wbarrier_value_copy);
4263 g_assert (klass->valuetype);
4265 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4267 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4268 size_t element_size = mono_class_value_size (klass, NULL);
4269 size_t size = count * element_size;
4270 mono_gc_memmove_atomic (dest, src, size);
4274 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4275 if (binary_protocol_is_heavy_enabled ()) {
4276 size_t element_size = mono_class_value_size (klass, NULL);
4278 for (i = 0; i < count; ++i) {
4279 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4280 (char*)src + i * element_size - sizeof (MonoObject),
4281 (mword) klass->gc_descr);
4286 remset.wbarrier_value_copy (dest, src, count, klass);
4290 * mono_gc_wbarrier_object_copy:
4292 * Write barrier to call when obj is the result of a clone or copy of an object.
4295 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4299 HEAVY_STAT (++stat_wbarrier_object_copy);
4301 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4302 size = mono_object_class (obj)->instance_size;
4303 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4304 size - sizeof (MonoObject));
4308 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4309 if (binary_protocol_is_heavy_enabled ())
4310 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4313 remset.wbarrier_object_copy (obj, src);
4318 * ######################################################################
4319 * ######## Other mono public interface functions.
4320 * ######################################################################
4323 #define REFS_SIZE 128
4326 MonoGCReferences callback;
4330 MonoObject *refs [REFS_SIZE];
4331 uintptr_t offsets [REFS_SIZE];
4335 #define HANDLE_PTR(ptr,obj) do { \
4337 if (hwi->count == REFS_SIZE) { \
4338 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4342 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4343 hwi->refs [hwi->count++] = *(ptr); \
4348 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4350 mword desc = sgen_obj_get_descriptor (start);
4352 #include "sgen-scan-object.h"
4356 walk_references (char *start, size_t size, void *data)
4358 HeapWalkInfo *hwi = data;
4361 collect_references (hwi, start, size);
4362 if (hwi->count || !hwi->called)
4363 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4367 * mono_gc_walk_heap:
4368 * @flags: flags for future use
4369 * @callback: a function pointer called for each object in the heap
4370 * @data: a user data pointer that is passed to callback
4372 * This function can be used to iterate over all the live objects in the heap:
4373 * for each object, @callback is invoked, providing info about the object's
4374 * location in memory, its class, its size and the objects it references.
4375 * For each referenced object it's offset from the object address is
4376 * reported in the offsets array.
4377 * The object references may be buffered, so the callback may be invoked
4378 * multiple times for the same object: in all but the first call, the size
4379 * argument will be zero.
4380 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4381 * profiler event handler.
4383 * Returns: a non-zero value if the GC doesn't support heap walking
4386 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4391 hwi.callback = callback;
4394 sgen_clear_nursery_fragments ();
4395 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4397 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4398 sgen_los_iterate_objects (walk_references, &hwi);
4404 mono_gc_collect (int generation)
4409 sgen_perform_collection (0, generation, "user request", TRUE);
4414 mono_gc_max_generation (void)
4420 mono_gc_collection_count (int generation)
4422 if (generation == 0)
4423 return gc_stats.minor_gc_count;
4424 return gc_stats.major_gc_count;
4428 mono_gc_get_used_size (void)
4432 tot = los_memory_usage;
4433 tot += nursery_section->next_data - nursery_section->data;
4434 tot += major_collector.get_used_size ();
4435 /* FIXME: account for pinned objects */
4441 mono_gc_get_los_limit (void)
4443 return MAX_SMALL_OBJ_SIZE;
4447 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4449 mono_unichar2 *new_end = str->chars + new_length;
4451 /* zero the discarded string. This null-delimits the string and allows
4452 * the space to be reclaimed by SGen. */
4454 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4455 CHECK_CANARY_FOR_OBJECT (str);
4456 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4457 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4459 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4462 str->length = new_length;
4466 mono_gc_user_markers_supported (void)
4472 mono_object_is_alive (MonoObject* o)
4478 mono_gc_get_generation (MonoObject *obj)
4480 if (ptr_in_nursery (obj))
4486 mono_gc_enable_events (void)
4491 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4493 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4497 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4499 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4503 mono_gc_weak_link_get (void **link_addr)
4505 void * volatile *link_addr_volatile;
4509 link_addr_volatile = link_addr;
4510 ptr = (void*)*link_addr_volatile;
4512 * At this point we have a hidden pointer. If the GC runs
4513 * here, it will not recognize the hidden pointer as a
4514 * reference, and if the object behind it is not referenced
4515 * elsewhere, it will be freed. Once the world is restarted
4516 * we reveal the pointer, giving us a pointer to a freed
4517 * object. To make sure we don't return it, we load the
4518 * hidden pointer again. If it's still the same, we can be
4519 * sure the object reference is valid.
4522 obj = (MonoObject*) REVEAL_POINTER (ptr);
4526 mono_memory_barrier ();
4529 * During the second bridge processing step the world is
4530 * running again. That step processes all weak links once
4531 * more to null those that refer to dead objects. Before that
4532 * is completed, those links must not be followed, so we
4533 * conservatively wait for bridge processing when any weak
4534 * link is dereferenced.
4536 if (G_UNLIKELY (bridge_processing_in_progress))
4537 mono_gc_wait_for_bridge_processing ();
4539 if ((void*)*link_addr_volatile != ptr)
4546 mono_gc_ephemeron_array_add (MonoObject *obj)
4548 EphemeronLinkNode *node;
4552 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4557 node->array = (char*)obj;
4558 node->next = ephemeron_list;
4559 ephemeron_list = node;
4561 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4568 mono_gc_set_allow_synchronous_major (gboolean flag)
4570 if (!major_collector.is_concurrent)
4573 allow_synchronous_major = flag;
4578 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4582 result = func (data);
4583 UNLOCK_INTERRUPTION;
4588 mono_gc_is_gc_thread (void)
4592 result = mono_thread_info_current () != NULL;
4598 is_critical_method (MonoMethod *method)
4600 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4604 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4608 va_start (ap, description_format);
4610 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4611 vfprintf (stderr, description_format, ap);
4613 fprintf (stderr, " - %s", fallback);
4614 fprintf (stderr, "\n");
4620 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4623 double val = strtod (opt, &endptr);
4624 if (endptr == opt) {
4625 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4628 else if (val < min || val > max) {
4629 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4637 mono_gc_base_init (void)
4639 MonoThreadInfoCallbacks cb;
4642 char *major_collector_opt = NULL;
4643 char *minor_collector_opt = NULL;
4644 size_t max_heap = 0;
4645 size_t soft_limit = 0;
4648 gboolean debug_print_allowance = FALSE;
4649 double allowance_ratio = 0, save_target = 0;
4650 gboolean have_split_nursery = FALSE;
4651 gboolean cement_enabled = TRUE;
4653 mono_counters_init ();
4656 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4659 /* already inited */
4662 /* being inited by another thread */
4666 /* we will init it */
4669 g_assert_not_reached ();
4671 } while (result != 0);
4673 SGEN_TV_GETTIME (sgen_init_timestamp);
4675 LOCK_INIT (gc_mutex);
4677 pagesize = mono_pagesize ();
4678 gc_debug_file = stderr;
4680 cb.thread_register = sgen_thread_register;
4681 cb.thread_detach = sgen_thread_detach;
4682 cb.thread_unregister = sgen_thread_unregister;
4683 cb.thread_attach = sgen_thread_attach;
4684 cb.mono_method_is_critical = (gpointer)is_critical_method;
4686 cb.thread_exit = mono_gc_pthread_exit;
4687 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4690 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4692 LOCK_INIT (sgen_interruption_mutex);
4694 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4695 opts = g_strsplit (env, ",", -1);
4696 for (ptr = opts; *ptr; ++ptr) {
4698 if (g_str_has_prefix (opt, "major=")) {
4699 opt = strchr (opt, '=') + 1;
4700 major_collector_opt = g_strdup (opt);
4701 } else if (g_str_has_prefix (opt, "minor=")) {
4702 opt = strchr (opt, '=') + 1;
4703 minor_collector_opt = g_strdup (opt);
4711 sgen_init_internal_allocator ();
4712 sgen_init_nursery_allocator ();
4713 sgen_init_fin_weak_hash ();
4715 sgen_init_hash_table ();
4716 sgen_init_descriptors ();
4717 sgen_init_gray_queues ();
4719 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4720 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4721 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4722 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4724 #ifndef HAVE_KW_THREAD
4725 mono_native_tls_alloc (&thread_info_key, NULL);
4726 #if defined(__APPLE__) || defined (HOST_WIN32)
4728 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4729 * where the two are the same.
4731 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4735 int tls_offset = -1;
4736 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4737 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4742 * This needs to happen before any internal allocations because
4743 * it inits the small id which is required for hazard pointer
4748 mono_thread_info_attach (&dummy);
4750 if (!minor_collector_opt) {
4751 sgen_simple_nursery_init (&sgen_minor_collector);
4753 if (!strcmp (minor_collector_opt, "simple")) {
4755 sgen_simple_nursery_init (&sgen_minor_collector);
4756 } else if (!strcmp (minor_collector_opt, "split")) {
4757 sgen_split_nursery_init (&sgen_minor_collector);
4758 have_split_nursery = TRUE;
4760 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4761 goto use_simple_nursery;
4765 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4766 use_marksweep_major:
4767 sgen_marksweep_init (&major_collector);
4768 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4769 sgen_marksweep_conc_init (&major_collector);
4771 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4772 goto use_marksweep_major;
4775 ///* Keep this the default for now */
4776 /* Precise marking is broken on all supported targets. Disable until fixed. */
4777 conservative_stack_mark = TRUE;
4779 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4782 gboolean usage_printed = FALSE;
4784 for (ptr = opts; *ptr; ++ptr) {
4786 if (!strcmp (opt, ""))
4788 if (g_str_has_prefix (opt, "major="))
4790 if (g_str_has_prefix (opt, "minor="))
4792 if (g_str_has_prefix (opt, "max-heap-size=")) {
4793 size_t max_heap_candidate = 0;
4794 opt = strchr (opt, '=') + 1;
4795 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4796 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4797 if (max_heap != max_heap_candidate)
4798 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4800 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4804 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4805 opt = strchr (opt, '=') + 1;
4806 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4807 if (soft_limit <= 0) {
4808 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4812 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4816 if (g_str_has_prefix (opt, "stack-mark=")) {
4817 opt = strchr (opt, '=') + 1;
4818 if (!strcmp (opt, "precise")) {
4819 conservative_stack_mark = FALSE;
4820 } else if (!strcmp (opt, "conservative")) {
4821 conservative_stack_mark = TRUE;
4823 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4824 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4828 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4829 opt = strchr (opt, '=') + 1;
4830 sgen_set_bridge_implementation (opt);
4833 if (g_str_has_prefix (opt, "toggleref-test")) {
4834 sgen_register_test_toggleref_callback ();
4839 if (g_str_has_prefix (opt, "nursery-size=")) {
4841 opt = strchr (opt, '=') + 1;
4842 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4843 #ifdef SGEN_ALIGN_NURSERY
4844 if ((val & (val - 1))) {
4845 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4849 if (val < SGEN_MAX_NURSERY_WASTE) {
4850 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4851 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4855 sgen_nursery_size = val;
4856 sgen_nursery_bits = 0;
4857 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4860 sgen_nursery_size = val;
4863 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4869 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4871 opt = strchr (opt, '=') + 1;
4872 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4873 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4878 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4880 opt = strchr (opt, '=') + 1;
4881 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4882 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4883 allowance_ratio = val;
4887 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4888 if (!major_collector.is_concurrent) {
4889 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4893 opt = strchr (opt, '=') + 1;
4895 if (!strcmp (opt, "yes")) {
4896 allow_synchronous_major = TRUE;
4897 } else if (!strcmp (opt, "no")) {
4898 allow_synchronous_major = FALSE;
4900 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4905 if (!strcmp (opt, "cementing")) {
4906 cement_enabled = TRUE;
4909 if (!strcmp (opt, "no-cementing")) {
4910 cement_enabled = FALSE;
4914 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4917 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4920 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4925 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4926 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4927 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4928 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4929 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4930 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4931 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4932 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4933 fprintf (stderr, " [no-]cementing\n");
4934 if (major_collector.is_concurrent)
4935 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4936 if (major_collector.print_gc_param_usage)
4937 major_collector.print_gc_param_usage ();
4938 if (sgen_minor_collector.print_gc_param_usage)
4939 sgen_minor_collector.print_gc_param_usage ();
4940 fprintf (stderr, " Experimental options:\n");
4941 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4942 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);
4943 fprintf (stderr, "\n");
4945 usage_printed = TRUE;
4950 if (major_collector.is_concurrent)
4951 sgen_workers_init (1);
4953 if (major_collector_opt)
4954 g_free (major_collector_opt);
4956 if (minor_collector_opt)
4957 g_free (minor_collector_opt);
4961 sgen_cement_init (cement_enabled);
4963 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4964 gboolean usage_printed = FALSE;
4966 opts = g_strsplit (env, ",", -1);
4967 for (ptr = opts; ptr && *ptr; ptr ++) {
4969 if (!strcmp (opt, ""))
4971 if (opt [0] >= '0' && opt [0] <= '9') {
4972 gc_debug_level = atoi (opt);
4977 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4978 gc_debug_file = fopen (rf, "wb");
4980 gc_debug_file = stderr;
4983 } else if (!strcmp (opt, "print-allowance")) {
4984 debug_print_allowance = TRUE;
4985 } else if (!strcmp (opt, "print-pinning")) {
4986 do_pin_stats = TRUE;
4987 } else if (!strcmp (opt, "verify-before-allocs")) {
4988 verify_before_allocs = 1;
4989 has_per_allocation_action = TRUE;
4990 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4991 char *arg = strchr (opt, '=') + 1;
4992 verify_before_allocs = atoi (arg);
4993 has_per_allocation_action = TRUE;
4994 } else if (!strcmp (opt, "collect-before-allocs")) {
4995 collect_before_allocs = 1;
4996 has_per_allocation_action = TRUE;
4997 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4998 char *arg = strchr (opt, '=') + 1;
4999 has_per_allocation_action = TRUE;
5000 collect_before_allocs = atoi (arg);
5001 } else if (!strcmp (opt, "verify-before-collections")) {
5002 whole_heap_check_before_collection = TRUE;
5003 } else if (!strcmp (opt, "check-at-minor-collections")) {
5004 consistency_check_at_minor_collection = TRUE;
5005 nursery_clear_policy = CLEAR_AT_GC;
5006 } else if (!strcmp (opt, "mod-union-consistency-check")) {
5007 if (!major_collector.is_concurrent) {
5008 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
5011 mod_union_consistency_check = TRUE;
5012 } else if (!strcmp (opt, "check-mark-bits")) {
5013 check_mark_bits_after_major_collection = TRUE;
5014 } else if (!strcmp (opt, "check-nursery-pinned")) {
5015 check_nursery_objects_pinned = TRUE;
5016 } else if (!strcmp (opt, "xdomain-checks")) {
5017 xdomain_checks = TRUE;
5018 } else if (!strcmp (opt, "clear-at-gc")) {
5019 nursery_clear_policy = CLEAR_AT_GC;
5020 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5021 nursery_clear_policy = CLEAR_AT_GC;
5022 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
5023 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
5024 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
5025 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
5026 } else if (!strcmp (opt, "check-scan-starts")) {
5027 do_scan_starts_check = TRUE;
5028 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5029 do_verify_nursery = TRUE;
5030 } else if (!strcmp (opt, "check-concurrent")) {
5031 if (!major_collector.is_concurrent) {
5032 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5035 do_concurrent_checks = TRUE;
5036 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5037 do_dump_nursery_content = TRUE;
5038 } else if (!strcmp (opt, "no-managed-allocator")) {
5039 sgen_set_use_managed_allocator (FALSE);
5040 } else if (!strcmp (opt, "disable-minor")) {
5041 disable_minor_collections = TRUE;
5042 } else if (!strcmp (opt, "disable-major")) {
5043 disable_major_collections = TRUE;
5044 } else if (g_str_has_prefix (opt, "heap-dump=")) {
5045 char *filename = strchr (opt, '=') + 1;
5046 nursery_clear_policy = CLEAR_AT_GC;
5047 heap_dump_file = fopen (filename, "w");
5048 if (heap_dump_file) {
5049 fprintf (heap_dump_file, "<sgen-dump>\n");
5050 do_pin_stats = TRUE;
5052 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5053 char *filename = strchr (opt, '=') + 1;
5054 char *colon = strrchr (filename, ':');
5057 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
5058 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
5063 binary_protocol_init (filename, (long long)limit);
5064 } else if (!strcmp (opt, "nursery-canaries")) {
5065 do_verify_nursery = TRUE;
5066 sgen_set_use_managed_allocator (FALSE);
5067 enable_nursery_canaries = TRUE;
5068 } else if (!strcmp (opt, "do-not-finalize")) {
5069 do_not_finalize = TRUE;
5070 } else if (!sgen_bridge_handle_gc_debug (opt)) {
5071 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5076 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);
5077 fprintf (stderr, "Valid <option>s are:\n");
5078 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5079 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5080 fprintf (stderr, " check-at-minor-collections\n");
5081 fprintf (stderr, " check-mark-bits\n");
5082 fprintf (stderr, " check-nursery-pinned\n");
5083 fprintf (stderr, " verify-before-collections\n");
5084 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5085 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5086 fprintf (stderr, " disable-minor\n");
5087 fprintf (stderr, " disable-major\n");
5088 fprintf (stderr, " xdomain-checks\n");
5089 fprintf (stderr, " check-concurrent\n");
5090 fprintf (stderr, " clear-[nursery-]at-gc\n");
5091 fprintf (stderr, " clear-at-tlab-creation\n");
5092 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5093 fprintf (stderr, " check-scan-starts\n");
5094 fprintf (stderr, " no-managed-allocator\n");
5095 fprintf (stderr, " print-allowance\n");
5096 fprintf (stderr, " print-pinning\n");
5097 fprintf (stderr, " heap-dump=<filename>\n");
5098 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5099 fprintf (stderr, " nursery-canaries\n");
5100 fprintf (stderr, " do-not-finalize\n");
5101 sgen_bridge_print_gc_debug_usage ();
5102 fprintf (stderr, "\n");
5104 usage_printed = TRUE;
5110 if (check_mark_bits_after_major_collection)
5111 nursery_clear_policy = CLEAR_AT_GC;
5113 if (major_collector.post_param_init)
5114 major_collector.post_param_init (&major_collector);
5116 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5118 memset (&remset, 0, sizeof (remset));
5120 sgen_card_table_init (&remset);
5126 mono_gc_get_gc_name (void)
5131 static MonoMethod *write_barrier_method;
5134 sgen_is_critical_method (MonoMethod *method)
5136 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5140 sgen_has_critical_method (void)
5142 return write_barrier_method || sgen_has_managed_allocator ();
5148 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5150 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5151 #ifdef SGEN_ALIGN_NURSERY
5152 // if (ptr_in_nursery (ptr)) return;
5154 * Masking out the bits might be faster, but we would have to use 64 bit
5155 * immediates, which might be slower.
5157 mono_mb_emit_ldarg (mb, 0);
5158 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5159 mono_mb_emit_byte (mb, CEE_SHR_UN);
5160 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5161 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5163 if (!major_collector.is_concurrent) {
5164 // if (!ptr_in_nursery (*ptr)) return;
5165 mono_mb_emit_ldarg (mb, 0);
5166 mono_mb_emit_byte (mb, CEE_LDIND_I);
5167 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5168 mono_mb_emit_byte (mb, CEE_SHR_UN);
5169 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5170 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5173 int label_continue1, label_continue2;
5174 int dereferenced_var;
5176 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5177 mono_mb_emit_ldarg (mb, 0);
5178 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5179 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5181 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5182 mono_mb_emit_ldarg (mb, 0);
5183 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5184 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5187 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5190 mono_mb_patch_branch (mb, label_continue_1);
5191 mono_mb_patch_branch (mb, label_continue_2);
5193 // Dereference and store in local var
5194 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5195 mono_mb_emit_ldarg (mb, 0);
5196 mono_mb_emit_byte (mb, CEE_LDIND_I);
5197 mono_mb_emit_stloc (mb, dereferenced_var);
5199 if (!major_collector.is_concurrent) {
5200 // if (*ptr < sgen_get_nursery_start ()) return;
5201 mono_mb_emit_ldloc (mb, dereferenced_var);
5202 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5203 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5205 // if (*ptr >= sgen_get_nursery_end ()) return;
5206 mono_mb_emit_ldloc (mb, dereferenced_var);
5207 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5208 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5215 mono_gc_get_write_barrier (void)
5218 MonoMethodBuilder *mb;
5219 MonoMethodSignature *sig;
5220 #ifdef MANAGED_WBARRIER
5221 int i, nursery_check_labels [3];
5223 #ifdef HAVE_KW_THREAD
5224 int stack_end_offset = -1;
5226 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5227 g_assert (stack_end_offset != -1);
5231 // FIXME: Maybe create a separate version for ctors (the branch would be
5232 // correctly predicted more times)
5233 if (write_barrier_method)
5234 return write_barrier_method;
5236 /* Create the IL version of mono_gc_barrier_generic_store () */
5237 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5238 sig->ret = &mono_defaults.void_class->byval_arg;
5239 sig->params [0] = &mono_defaults.int_class->byval_arg;
5241 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5244 #ifdef MANAGED_WBARRIER
5245 emit_nursery_check (mb, nursery_check_labels);
5247 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5251 LDC_PTR sgen_cardtable
5253 address >> CARD_BITS
5257 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5258 LDC_PTR card_table_mask
5265 mono_mb_emit_ptr (mb, sgen_cardtable);
5266 mono_mb_emit_ldarg (mb, 0);
5267 mono_mb_emit_icon (mb, CARD_BITS);
5268 mono_mb_emit_byte (mb, CEE_SHR_UN);
5269 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5270 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5271 mono_mb_emit_byte (mb, CEE_AND);
5273 mono_mb_emit_byte (mb, CEE_ADD);
5274 mono_mb_emit_icon (mb, 1);
5275 mono_mb_emit_byte (mb, CEE_STIND_I1);
5278 for (i = 0; i < 3; ++i) {
5279 if (nursery_check_labels [i])
5280 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5282 mono_mb_emit_byte (mb, CEE_RET);
5284 mono_mb_emit_ldarg (mb, 0);
5285 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5286 mono_mb_emit_byte (mb, CEE_RET);
5289 res = mono_mb_create_method (mb, sig, 16);
5293 if (write_barrier_method) {
5294 /* Already created */
5295 mono_free_method (res);
5297 /* double-checked locking */
5298 mono_memory_barrier ();
5299 write_barrier_method = res;
5303 return write_barrier_method;
5307 mono_gc_get_description (void)
5309 return g_strdup ("sgen");
5313 mono_gc_set_desktop_mode (void)
5318 mono_gc_is_moving (void)
5324 mono_gc_is_disabled (void)
5330 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5337 sgen_get_nursery_clear_policy (void)
5339 return nursery_clear_policy;
5343 sgen_get_array_fill_vtable (void)
5345 if (!array_fill_vtable) {
5346 static MonoClass klass;
5347 static char _vtable[sizeof(MonoVTable)+8];
5348 MonoVTable* vtable = (MonoVTable*) ALIGN_TO(_vtable, 8);
5351 MonoDomain *domain = mono_get_root_domain ();
5354 klass.element_class = mono_defaults.byte_class;
5356 klass.instance_size = sizeof (MonoArray);
5357 klass.sizes.element_size = 1;
5358 klass.name = "array_filler_type";
5360 vtable->klass = &klass;
5362 vtable->gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5365 array_fill_vtable = vtable;
5367 return array_fill_vtable;
5377 sgen_gc_unlock (void)
5379 gboolean try_free = sgen_try_free_some_memory;
5380 sgen_try_free_some_memory = FALSE;
5381 mono_mutex_unlock (&gc_mutex);
5382 MONO_GC_UNLOCKED ();
5384 mono_thread_hazardous_try_free_some ();
5388 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5390 major_collector.iterate_live_block_ranges (callback);
5394 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5396 major_collector.scan_card_table (FALSE, queue);
5400 sgen_get_major_collector (void)
5402 return &major_collector;
5405 void mono_gc_set_skip_thread (gboolean skip)
5407 SgenThreadInfo *info = mono_thread_info_current ();
5410 info->gc_disabled = skip;
5415 sgen_get_remset (void)
5421 mono_gc_get_vtable_bits (MonoClass *class)
5424 /* FIXME move this to the bridge code */
5425 if (sgen_need_bridge_processing ()) {
5426 switch (sgen_bridge_class_kind (class)) {
5427 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5428 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5429 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5431 case GC_BRIDGE_OPAQUE_CLASS:
5432 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5436 if (fin_callbacks.is_class_finalization_aware) {
5437 if (fin_callbacks.is_class_finalization_aware (class))
5438 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5444 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5451 sgen_check_whole_heap_stw (void)
5453 sgen_stop_world (0);
5454 sgen_clear_nursery_fragments ();
5455 sgen_check_whole_heap (FALSE);
5456 sgen_restart_world (0, NULL);
5460 sgen_gc_event_moves (void)
5462 if (moved_objects_idx) {
5463 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5464 moved_objects_idx = 0;
5469 sgen_timestamp (void)
5471 SGEN_TV_DECLARE (timestamp);
5472 SGEN_TV_GETTIME (timestamp);
5473 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5477 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5479 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5480 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5482 fin_callbacks = *callbacks;
5489 #endif /* HAVE_SGEN_GC */