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;
283 * If the major collector is concurrent and this is FALSE, we will
284 * never initiate a synchronous major collection, unless requested via
287 static gboolean allow_synchronous_major = TRUE;
288 static gboolean disable_minor_collections = FALSE;
289 static gboolean disable_major_collections = FALSE;
290 gboolean do_pin_stats = FALSE;
291 static gboolean do_verify_nursery = FALSE;
292 static gboolean do_dump_nursery_content = FALSE;
293 static gboolean enable_nursery_canaries = FALSE;
295 #ifdef HEAVY_STATISTICS
296 guint64 stat_objects_alloced_degraded = 0;
297 guint64 stat_bytes_alloced_degraded = 0;
299 guint64 stat_copy_object_called_nursery = 0;
300 guint64 stat_objects_copied_nursery = 0;
301 guint64 stat_copy_object_called_major = 0;
302 guint64 stat_objects_copied_major = 0;
304 guint64 stat_scan_object_called_nursery = 0;
305 guint64 stat_scan_object_called_major = 0;
307 guint64 stat_slots_allocated_in_vain;
309 guint64 stat_nursery_copy_object_failed_from_space = 0;
310 guint64 stat_nursery_copy_object_failed_forwarded = 0;
311 guint64 stat_nursery_copy_object_failed_pinned = 0;
312 guint64 stat_nursery_copy_object_failed_to_space = 0;
314 static int stat_wbarrier_add_to_global_remset = 0;
315 static int stat_wbarrier_set_field = 0;
316 static int stat_wbarrier_set_arrayref = 0;
317 static int stat_wbarrier_arrayref_copy = 0;
318 static int stat_wbarrier_generic_store = 0;
319 static int stat_wbarrier_generic_store_atomic = 0;
320 static int stat_wbarrier_set_root = 0;
321 static int stat_wbarrier_value_copy = 0;
322 static int stat_wbarrier_object_copy = 0;
325 static guint64 stat_pinned_objects = 0;
327 static guint64 time_minor_pre_collection_fragment_clear = 0;
328 static guint64 time_minor_pinning = 0;
329 static guint64 time_minor_scan_remsets = 0;
330 static guint64 time_minor_scan_pinned = 0;
331 static guint64 time_minor_scan_registered_roots = 0;
332 static guint64 time_minor_scan_thread_data = 0;
333 static guint64 time_minor_finish_gray_stack = 0;
334 static guint64 time_minor_fragment_creation = 0;
336 static guint64 time_major_pre_collection_fragment_clear = 0;
337 static guint64 time_major_pinning = 0;
338 static guint64 time_major_scan_pinned = 0;
339 static guint64 time_major_scan_registered_roots = 0;
340 static guint64 time_major_scan_thread_data = 0;
341 static guint64 time_major_scan_alloc_pinned = 0;
342 static guint64 time_major_scan_finalized = 0;
343 static guint64 time_major_scan_big_objects = 0;
344 static guint64 time_major_finish_gray_stack = 0;
345 static guint64 time_major_free_bigobjs = 0;
346 static guint64 time_major_los_sweep = 0;
347 static guint64 time_major_sweep = 0;
348 static guint64 time_major_fragment_creation = 0;
350 static guint64 time_max = 0;
352 static SGEN_TV_DECLARE (time_major_conc_collection_start);
353 static SGEN_TV_DECLARE (time_major_conc_collection_end);
355 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
356 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
358 int gc_debug_level = 0;
361 static MonoGCFinalizerCallbacks fin_callbacks;
365 mono_gc_flush_info (void)
367 fflush (gc_debug_file);
371 #define TV_DECLARE SGEN_TV_DECLARE
372 #define TV_GETTIME SGEN_TV_GETTIME
373 #define TV_ELAPSED SGEN_TV_ELAPSED
375 SGEN_TV_DECLARE (sgen_init_timestamp);
377 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
379 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
381 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
382 #define object_is_pinned SGEN_OBJECT_IS_PINNED
383 #define pin_object SGEN_PIN_OBJECT
385 #define ptr_in_nursery sgen_ptr_in_nursery
387 #define LOAD_VTABLE SGEN_LOAD_VTABLE
390 safe_name (void* obj)
392 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
393 return vt->klass->name;
397 nursery_canaries_enabled (void)
399 return enable_nursery_canaries;
402 #define safe_object_get_size sgen_safe_object_get_size
405 sgen_safe_name (void* obj)
407 return safe_name (obj);
411 * ######################################################################
412 * ######## Global data.
413 * ######################################################################
415 LOCK_DECLARE (gc_mutex);
416 gboolean sgen_try_free_some_memory;
418 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
420 static mword pagesize = 4096;
421 size_t degraded_mode = 0;
423 static mword bytes_pinned_from_failed_allocation = 0;
425 GCMemSection *nursery_section = NULL;
426 static volatile mword lowest_heap_address = ~(mword)0;
427 static volatile mword highest_heap_address = 0;
429 LOCK_DECLARE (sgen_interruption_mutex);
431 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
432 struct _FinalizeReadyEntry {
433 FinalizeReadyEntry *next;
437 typedef struct _EphemeronLinkNode EphemeronLinkNode;
439 struct _EphemeronLinkNode {
440 EphemeronLinkNode *next;
449 int current_collection_generation = -1;
450 volatile gboolean concurrent_collection_in_progress = FALSE;
452 /* objects that are ready to be finalized */
453 static FinalizeReadyEntry *fin_ready_list = NULL;
454 static FinalizeReadyEntry *critical_fin_list = NULL;
456 static EphemeronLinkNode *ephemeron_list;
458 /* registered roots: the key to the hash is the root start address */
460 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
462 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
463 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
464 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
465 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
467 static mword roots_size = 0; /* amount of memory in the root set */
469 #define GC_ROOT_NUM 32
471 int count; /* must be the first field */
472 void *objects [GC_ROOT_NUM];
473 int root_types [GC_ROOT_NUM];
474 uintptr_t extra_info [GC_ROOT_NUM];
478 notify_gc_roots (GCRootReport *report)
482 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
487 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
489 if (report->count == GC_ROOT_NUM)
490 notify_gc_roots (report);
491 report->objects [report->count] = object;
492 report->root_types [report->count] = rtype;
493 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
496 MonoNativeTlsKey thread_info_key;
498 #ifdef HAVE_KW_THREAD
499 __thread SgenThreadInfo *sgen_thread_info;
500 __thread char *stack_end;
503 /* The size of a TLAB */
504 /* The bigger the value, the less often we have to go to the slow path to allocate a new
505 * one, but the more space is wasted by threads not allocating much memory.
507 * FIXME: Make this self-tuning for each thread.
509 guint32 tlab_size = (1024 * 4);
511 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
513 /* Functions supplied by the runtime to be called by the GC */
514 static MonoGCCallbacks gc_callbacks;
516 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
518 #define ALIGN_UP SGEN_ALIGN_UP
520 #define MOVED_OBJECTS_NUM 64
521 static void *moved_objects [MOVED_OBJECTS_NUM];
522 static int moved_objects_idx = 0;
524 /* Vtable of the objects used to fill out nursery fragments before a collection */
525 static MonoVTable *array_fill_vtable;
527 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
528 MonoNativeThreadId main_gc_thread = NULL;
531 /*Object was pinned during the current collection*/
532 static mword objects_pinned;
535 * ######################################################################
536 * ######## Macros and function declarations.
537 * ######################################################################
540 typedef SgenGrayQueue GrayQueue;
542 /* forward declarations */
543 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
544 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
545 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
546 static void report_finalizer_roots (void);
547 static void report_registered_roots (void);
549 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
550 static void finish_gray_stack (int generation, GrayQueue *queue);
552 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
555 static void init_stats (void);
557 static int mark_ephemerons_in_range (ScanCopyContext ctx);
558 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
559 static void null_ephemerons_for_domain (MonoDomain *domain);
561 SgenObjectOperations current_object_ops;
562 SgenMajorCollector major_collector;
563 SgenMinorCollector sgen_minor_collector;
564 static GrayQueue gray_queue;
566 static SgenRememberedSet remset;
568 /* The gray queue to use from the main collection thread. */
569 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
572 * The gray queue a worker job must use. If we're not parallel or
573 * concurrent, we use the main gray queue.
575 static SgenGrayQueue*
576 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
578 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
582 gray_queue_redirect (SgenGrayQueue *queue)
584 gboolean wake = FALSE;
587 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
590 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
595 g_assert (concurrent_collection_in_progress);
596 if (sgen_workers_have_started ()) {
597 sgen_workers_ensure_awake ();
599 if (concurrent_collection_in_progress)
600 g_assert (current_collection_generation == -1);
606 gray_queue_enable_redirect (SgenGrayQueue *queue)
608 if (!concurrent_collection_in_progress)
611 sgen_gray_queue_set_alloc_prepare (queue, gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
612 gray_queue_redirect (queue);
616 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
618 while (start < end) {
622 if (!*(void**)start) {
623 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
628 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
634 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
635 CHECK_CANARY_FOR_OBJECT (obj);
636 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
637 callback (obj, size, data);
638 CANARIFY_SIZE (size);
640 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
648 need_remove_object_for_domain (char *start, MonoDomain *domain)
650 if (mono_object_domain (start) == domain) {
651 SGEN_LOG (4, "Need to cleanup object %p", start);
652 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
659 process_object_for_domain_clearing (char *start, MonoDomain *domain)
661 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
662 if (vt->klass == mono_defaults.internal_thread_class)
663 g_assert (mono_object_domain (start) == mono_get_root_domain ());
664 /* The object could be a proxy for an object in the domain
666 #ifndef DISABLE_REMOTING
667 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
668 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
670 /* The server could already have been zeroed out, so
671 we need to check for that, too. */
672 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
673 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
674 ((MonoRealProxy*)start)->unwrapped_server = NULL;
681 clear_domain_process_object (char *obj, MonoDomain *domain)
685 process_object_for_domain_clearing (obj, domain);
686 remove = need_remove_object_for_domain (obj, domain);
688 if (remove && ((MonoObject*)obj)->synchronisation) {
689 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
691 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
698 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
700 if (clear_domain_process_object (obj, domain)) {
701 CANARIFY_SIZE (size);
702 memset (obj, 0, size);
707 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
709 clear_domain_process_object (obj, domain);
713 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
715 if (need_remove_object_for_domain (obj, domain))
716 major_collector.free_non_pinned_object (obj, size);
720 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
722 if (need_remove_object_for_domain (obj, domain))
723 major_collector.free_pinned_object (obj, size);
727 * When appdomains are unloaded we can easily remove objects that have finalizers,
728 * but all the others could still be present in random places on the heap.
729 * We need a sweep to get rid of them even though it's going to be costly
731 * The reason we need to remove them is because we access the vtable and class
732 * structures to know the object size and the reference bitmap: once the domain is
733 * unloaded the point to random memory.
736 mono_gc_clear_domain (MonoDomain * domain)
738 LOSObject *bigobj, *prev;
743 binary_protocol_domain_unload_begin (domain);
747 if (concurrent_collection_in_progress)
748 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
749 g_assert (!concurrent_collection_in_progress);
751 sgen_process_fin_stage_entries ();
752 sgen_process_dislink_stage_entries ();
754 sgen_clear_nursery_fragments ();
756 if (xdomain_checks && domain != mono_get_root_domain ()) {
757 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
758 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
759 sgen_check_for_xdomain_refs ();
762 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
763 to memory returned to the OS.*/
764 null_ephemerons_for_domain (domain);
766 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
767 sgen_null_links_for_domain (domain, i);
769 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
770 sgen_remove_finalizers_for_domain (domain, i);
772 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
773 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
775 /* We need two passes over major and large objects because
776 freeing such objects might give their memory back to the OS
777 (in the case of large objects) or obliterate its vtable
778 (pinned objects with major-copying or pinned and non-pinned
779 objects with major-mark&sweep), but we might need to
780 dereference a pointer from an object to another object if
781 the first object is a proxy. */
782 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
783 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
784 clear_domain_process_object (bigobj->data, domain);
787 for (bigobj = los_object_list; bigobj;) {
788 if (need_remove_object_for_domain (bigobj->data, domain)) {
789 LOSObject *to_free = bigobj;
791 prev->next = bigobj->next;
793 los_object_list = bigobj->next;
794 bigobj = bigobj->next;
795 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
796 sgen_los_free_object (to_free);
800 bigobj = bigobj->next;
802 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
803 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
805 if (domain == mono_get_root_domain ()) {
806 if (G_UNLIKELY (do_pin_stats))
807 sgen_pin_stats_print_class_stats ();
808 sgen_object_layout_dump (stdout);
811 sgen_restart_world (0, NULL);
813 binary_protocol_domain_unload_end (domain);
814 binary_protocol_flush_buffers (FALSE);
820 * sgen_add_to_global_remset:
822 * The global remset contains locations which point into newspace after
823 * a minor collection. This can happen if the objects they point to are pinned.
825 * LOCKING: If called from a parallel collector, the global remset
826 * lock must be held. For serial collectors that is not necessary.
829 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
831 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
833 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
835 if (!major_collector.is_concurrent) {
836 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
838 if (current_collection_generation == -1)
839 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
842 if (!object_is_pinned (obj))
843 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");
844 else if (sgen_cement_lookup_or_register (obj))
847 remset.record_pointer (ptr);
849 if (G_UNLIKELY (do_pin_stats))
850 sgen_pin_stats_register_global_remset (obj);
852 SGEN_LOG (8, "Adding global remset for %p", ptr);
853 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
857 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
858 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
859 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
860 vt->klass->name_space, vt->klass->name);
866 * sgen_drain_gray_stack:
868 * Scan objects in the gray stack until the stack is empty. This should be called
869 * frequently after each object is copied, to achieve better locality and cache
872 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
876 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
878 ScanObjectFunc scan_func = ctx.scan_func;
879 GrayQueue *queue = ctx.queue;
881 if (current_collection_generation == GENERATION_OLD && major_collector.drain_gray_stack)
882 return major_collector.drain_gray_stack (ctx);
886 for (i = 0; i != max_objs; ++i) {
889 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
892 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
893 scan_func (obj, desc, queue);
895 } while (max_objs < 0);
900 * Addresses in the pin queue are already sorted. This function finds
901 * the object header for each address and pins the object. The
902 * addresses must be inside the nursery section. The (start of the)
903 * address array is overwritten with the addresses of the actually
904 * pinned objects. Return the number of pinned objects.
907 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
909 GCMemSection *section = nursery_section;
910 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
911 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
912 void *start_nursery = section->data;
913 void *end_nursery = section->next_data;
918 void *pinning_front = start_nursery;
920 void **definitely_pinned = start;
921 ScanObjectFunc scan_func = ctx.scan_func;
922 SgenGrayQueue *queue = ctx.queue;
924 sgen_nursery_allocator_prepare_for_pinning ();
926 while (start < end) {
927 void *obj_to_pin = NULL;
928 size_t obj_to_pin_size = 0;
933 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
934 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
941 SGEN_LOG (5, "Considering pinning addr %p", addr);
942 /* We've already processed everything up to pinning_front. */
943 if (addr < pinning_front) {
949 * Find the closest scan start <= addr. We might search backward in the
950 * scan_starts array because entries might be NULL. In the worst case we
951 * start at start_nursery.
953 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
954 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
955 search_start = (void*)section->scan_starts [idx];
956 if (!search_start || search_start > addr) {
959 search_start = section->scan_starts [idx];
960 if (search_start && search_start <= addr)
963 if (!search_start || search_start > addr)
964 search_start = start_nursery;
968 * If the pinning front is closer than the scan start we found, start
969 * searching at the front.
971 if (search_start < pinning_front)
972 search_start = pinning_front;
975 * Now addr should be in an object a short distance from search_start.
977 * search_start must point to zeroed mem or point to an object.
980 size_t obj_size, canarified_obj_size;
983 if (!*(void**)search_start) {
984 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
985 /* The loop condition makes sure we don't overrun addr. */
989 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
992 * Filler arrays are marked by an invalid sync word. We don't
993 * consider them for pinning. They are not delimited by canaries,
996 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
997 CHECK_CANARY_FOR_OBJECT (search_start);
998 CANARIFY_SIZE (canarified_obj_size);
1000 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
1001 /* This is the object we're looking for. */
1002 obj_to_pin = search_start;
1003 obj_to_pin_size = canarified_obj_size;
1008 /* Skip to the next object */
1009 search_start = (void*)((char*)search_start + canarified_obj_size);
1010 } while (search_start <= addr);
1012 /* We've searched past the address we were looking for. */
1014 pinning_front = search_start;
1015 goto next_pin_queue_entry;
1019 * We've found an object to pin. It might still be a dummy array, but we
1020 * can advance the pinning front in any case.
1022 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1025 * If this is a dummy array marking the beginning of a nursery
1026 * fragment, we don't pin it.
1028 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1029 goto next_pin_queue_entry;
1032 * Finally - pin the object!
1034 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1036 scan_func (obj_to_pin, desc, queue);
1038 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1039 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1040 binary_protocol_pin (obj_to_pin,
1041 (gpointer)LOAD_VTABLE (obj_to_pin),
1042 safe_object_get_size (obj_to_pin));
1044 #ifdef ENABLE_DTRACE
1045 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1046 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1047 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1048 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1049 sgen_safe_object_get_size (obj_to_pin),
1050 vt->klass->name_space, vt->klass->name, gen);
1054 pin_object (obj_to_pin);
1055 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1056 if (G_UNLIKELY (do_pin_stats))
1057 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1058 definitely_pinned [count] = obj_to_pin;
1062 next_pin_queue_entry:
1066 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1067 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1068 GCRootReport report;
1070 for (idx = 0; idx < count; ++idx)
1071 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1072 notify_gc_roots (&report);
1074 stat_pinned_objects += count;
1079 pin_objects_in_nursery (ScanCopyContext ctx)
1083 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
1086 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1087 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
1091 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
1092 * when we can't promote an object because we're out of memory.
1095 sgen_pin_object (void *object, GrayQueue *queue)
1098 * All pinned objects are assumed to have been staged, so we need to stage as well.
1099 * Also, the count of staged objects shows that "late pinning" happened.
1101 sgen_pin_stage_ptr (object);
1103 SGEN_PIN_OBJECT (object);
1104 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1107 if (G_UNLIKELY (do_pin_stats))
1108 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1110 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1112 #ifdef ENABLE_DTRACE
1113 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1114 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1115 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1116 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1121 /* Sort the addresses in array in increasing order.
1122 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1125 sgen_sort_addresses (void **array, size_t size)
1130 for (i = 1; i < size; ++i) {
1133 size_t parent = (child - 1) / 2;
1135 if (array [parent] >= array [child])
1138 tmp = array [parent];
1139 array [parent] = array [child];
1140 array [child] = tmp;
1146 for (i = size - 1; i > 0; --i) {
1149 array [i] = array [0];
1155 while (root * 2 + 1 <= end) {
1156 size_t child = root * 2 + 1;
1158 if (child < end && array [child] < array [child + 1])
1160 if (array [root] >= array [child])
1164 array [root] = array [child];
1165 array [child] = tmp;
1173 * Scan the memory between start and end and queue values which could be pointers
1174 * to the area between start_nursery and end_nursery for later consideration.
1175 * Typically used for thread stacks.
1178 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1182 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1183 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1186 while (start < end) {
1187 if (*start >= start_nursery && *start < end_nursery) {
1189 * *start can point to the middle of an object
1190 * note: should we handle pointing at the end of an object?
1191 * pinning in C# code disallows pointing at the end of an object
1192 * but there is some small chance that an optimizing C compiler
1193 * may keep the only reference to an object by pointing
1194 * at the end of it. We ignore this small chance for now.
1195 * Pointers to the end of an object are indistinguishable
1196 * from pointers to the start of the next object in memory
1197 * so if we allow that we'd need to pin two objects...
1198 * We queue the pointer in an array, the
1199 * array will then be sorted and uniqued. This way
1200 * we can coalesce several pinning pointers and it should
1201 * be faster since we'd do a memory scan with increasing
1202 * addresses. Note: we can align the address to the allocation
1203 * alignment, so the unique process is more effective.
1205 mword addr = (mword)*start;
1206 addr &= ~(ALLOC_ALIGN - 1);
1207 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1208 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1209 sgen_pin_stage_ptr ((void*)addr);
1210 binary_protocol_pin_stage (start, (void*)addr);
1213 if (G_UNLIKELY (do_pin_stats)) {
1214 if (ptr_in_nursery ((void*)addr))
1215 sgen_pin_stats_register_address ((char*)addr, pin_type);
1221 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1225 * The first thing we do in a collection is to identify pinned objects.
1226 * This function considers all the areas of memory that need to be
1227 * conservatively scanned.
1230 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1234 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);
1235 /* objects pinned from the API are inside these roots */
1236 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1237 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1238 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1239 } SGEN_HASH_TABLE_FOREACH_END;
1240 /* now deal with the thread stacks
1241 * in the future we should be able to conservatively scan only:
1242 * *) the cpu registers
1243 * *) the unmanaged stack frames
1244 * *) the _last_ managed stack frame
1245 * *) pointers slots in managed frames
1247 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1251 unpin_objects_from_queue (SgenGrayQueue *queue)
1256 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1259 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1260 SGEN_UNPIN_OBJECT (addr);
1265 CopyOrMarkObjectFunc func;
1267 } UserCopyOrMarkData;
1270 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1272 UserCopyOrMarkData *data = gc_data;
1274 data->func (obj, data->queue);
1278 * The memory area from start_root to end_root contains pointers to objects.
1279 * Their position is precisely described by @desc (this means that the pointer
1280 * can be either NULL or the pointer to the start of an object).
1281 * This functions copies them to to_space updates them.
1283 * This function is not thread-safe!
1286 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1288 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1289 SgenGrayQueue *queue = ctx.queue;
1291 switch (desc & ROOT_DESC_TYPE_MASK) {
1292 case ROOT_DESC_BITMAP:
1293 desc >>= ROOT_DESC_TYPE_SHIFT;
1295 if ((desc & 1) && *start_root) {
1296 copy_func (start_root, queue);
1297 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1303 case ROOT_DESC_COMPLEX: {
1304 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1305 gsize bwords = (*bitmap_data) - 1;
1306 void **start_run = start_root;
1308 while (bwords-- > 0) {
1309 gsize bmap = *bitmap_data++;
1310 void **objptr = start_run;
1312 if ((bmap & 1) && *objptr) {
1313 copy_func (objptr, queue);
1314 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1319 start_run += GC_BITS_PER_WORD;
1323 case ROOT_DESC_USER: {
1324 UserCopyOrMarkData data = { copy_func, queue };
1325 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1326 marker (start_root, single_arg_user_copy_or_mark, &data);
1329 case ROOT_DESC_RUN_LEN:
1330 g_assert_not_reached ();
1332 g_assert_not_reached ();
1337 reset_heap_boundaries (void)
1339 lowest_heap_address = ~(mword)0;
1340 highest_heap_address = 0;
1344 sgen_update_heap_boundaries (mword low, mword high)
1349 old = lowest_heap_address;
1352 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1355 old = highest_heap_address;
1358 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1362 * Allocate and setup the data structures needed to be able to allocate objects
1363 * in the nursery. The nursery is stored in nursery_section.
1366 alloc_nursery (void)
1368 GCMemSection *section;
1373 if (nursery_section)
1375 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1376 /* later we will alloc a larger area for the nursery but only activate
1377 * what we need. The rest will be used as expansion if we have too many pinned
1378 * objects in the existing nursery.
1380 /* FIXME: handle OOM */
1381 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1383 alloc_size = sgen_nursery_size;
1385 /* If there isn't enough space even for the nursery we should simply abort. */
1386 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1388 #ifdef SGEN_ALIGN_NURSERY
1389 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1391 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1393 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1394 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 ());
1395 section->data = section->next_data = data;
1396 section->size = alloc_size;
1397 section->end_data = data + sgen_nursery_size;
1398 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1399 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1400 section->num_scan_start = scan_starts;
1402 nursery_section = section;
1404 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1408 mono_gc_get_nursery (int *shift_bits, size_t *size)
1410 *size = sgen_nursery_size;
1411 #ifdef SGEN_ALIGN_NURSERY
1412 *shift_bits = DEFAULT_NURSERY_BITS;
1416 return sgen_get_nursery_start ();
1420 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1422 SgenThreadInfo *info = mono_thread_info_current ();
1424 /* Could be called from sgen_thread_unregister () with a NULL info */
1427 info->stopped_domain = domain;
1432 mono_gc_precise_stack_mark_enabled (void)
1434 return !conservative_stack_mark;
1438 mono_gc_get_logfile (void)
1440 return gc_debug_file;
1444 report_finalizer_roots_list (FinalizeReadyEntry *list)
1446 GCRootReport report;
1447 FinalizeReadyEntry *fin;
1450 for (fin = list; fin; fin = fin->next) {
1453 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1455 notify_gc_roots (&report);
1459 report_finalizer_roots (void)
1461 report_finalizer_roots_list (fin_ready_list);
1462 report_finalizer_roots_list (critical_fin_list);
1465 static GCRootReport *root_report;
1468 single_arg_report_root (void **obj, void *gc_data)
1471 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1475 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1477 switch (desc & ROOT_DESC_TYPE_MASK) {
1478 case ROOT_DESC_BITMAP:
1479 desc >>= ROOT_DESC_TYPE_SHIFT;
1481 if ((desc & 1) && *start_root) {
1482 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1488 case ROOT_DESC_COMPLEX: {
1489 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1490 gsize bwords = (*bitmap_data) - 1;
1491 void **start_run = start_root;
1493 while (bwords-- > 0) {
1494 gsize bmap = *bitmap_data++;
1495 void **objptr = start_run;
1497 if ((bmap & 1) && *objptr) {
1498 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1503 start_run += GC_BITS_PER_WORD;
1507 case ROOT_DESC_USER: {
1508 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1509 root_report = report;
1510 marker (start_root, single_arg_report_root, NULL);
1513 case ROOT_DESC_RUN_LEN:
1514 g_assert_not_reached ();
1516 g_assert_not_reached ();
1521 report_registered_roots_by_type (int root_type)
1523 GCRootReport report;
1527 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1528 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1529 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1530 } SGEN_HASH_TABLE_FOREACH_END;
1531 notify_gc_roots (&report);
1535 report_registered_roots (void)
1537 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1538 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1542 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1544 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1545 SgenGrayQueue *queue = ctx.queue;
1546 FinalizeReadyEntry *fin;
1548 for (fin = list; fin; fin = fin->next) {
1551 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1552 copy_func (&fin->object, queue);
1557 generation_name (int generation)
1559 switch (generation) {
1560 case GENERATION_NURSERY: return "nursery";
1561 case GENERATION_OLD: return "old";
1562 default: g_assert_not_reached ();
1567 sgen_generation_name (int generation)
1569 return generation_name (generation);
1572 SgenObjectOperations *
1573 sgen_get_current_object_ops (void){
1574 return ¤t_object_ops;
1579 finish_gray_stack (int generation, GrayQueue *queue)
1583 int done_with_ephemerons, ephemeron_rounds = 0;
1584 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1585 ScanObjectFunc scan_func = current_object_ops.scan_object;
1586 ScanCopyContext ctx = { scan_func, copy_func, queue };
1587 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1588 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1591 * We copied all the reachable objects. Now it's the time to copy
1592 * the objects that were not referenced by the roots, but by the copied objects.
1593 * we built a stack of objects pointed to by gray_start: they are
1594 * additional roots and we may add more items as we go.
1595 * We loop until gray_start == gray_objects which means no more objects have
1596 * been added. Note this is iterative: no recursion is involved.
1597 * We need to walk the LO list as well in search of marked big objects
1598 * (use a flag since this is needed only on major collections). We need to loop
1599 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1600 * To achieve better cache locality and cache usage, we drain the gray stack
1601 * frequently, after each object is copied, and just finish the work here.
1603 sgen_drain_gray_stack (-1, ctx);
1605 SGEN_LOG (2, "%s generation done", generation_name (generation));
1608 Reset bridge data, we might have lingering data from a previous collection if this is a major
1609 collection trigged by minor overflow.
1611 We must reset the gathered bridges since their original block might be evacuated due to major
1612 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1614 if (sgen_need_bridge_processing ())
1615 sgen_bridge_reset_data ();
1618 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1619 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1620 * objects that are in fact reachable.
1622 done_with_ephemerons = 0;
1624 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1625 sgen_drain_gray_stack (-1, ctx);
1627 } while (!done_with_ephemerons);
1629 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1631 if (sgen_need_bridge_processing ()) {
1632 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1633 sgen_drain_gray_stack (-1, ctx);
1634 sgen_collect_bridge_objects (generation, ctx);
1635 if (generation == GENERATION_OLD)
1636 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1639 Do the first bridge step here, as the collector liveness state will become useless after that.
1641 An important optimization is to only proccess the possibly dead part of the object graph and skip
1642 over all live objects as we transitively know everything they point must be alive too.
1644 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1646 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1647 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1650 sgen_bridge_processing_stw_step ();
1654 Make sure we drain the gray stack before processing disappearing links and finalizers.
1655 If we don't make sure it is empty we might wrongly see a live object as dead.
1657 sgen_drain_gray_stack (-1, ctx);
1660 We must clear weak links that don't track resurrection before processing object ready for
1661 finalization so they can be cleared before that.
1663 sgen_null_link_in_range (generation, TRUE, ctx);
1664 if (generation == GENERATION_OLD)
1665 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1668 /* walk the finalization queue and move also the objects that need to be
1669 * finalized: use the finalized objects as new roots so the objects they depend
1670 * on are also not reclaimed. As with the roots above, only objects in the nursery
1671 * are marked/copied.
1673 sgen_finalize_in_range (generation, ctx);
1674 if (generation == GENERATION_OLD)
1675 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1676 /* drain the new stack that might have been created */
1677 SGEN_LOG (6, "Precise scan of gray area post fin");
1678 sgen_drain_gray_stack (-1, ctx);
1681 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1683 done_with_ephemerons = 0;
1685 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1686 sgen_drain_gray_stack (-1, ctx);
1688 } while (!done_with_ephemerons);
1691 * Clear ephemeron pairs with unreachable keys.
1692 * We pass the copy func so we can figure out if an array was promoted or not.
1694 clear_unreachable_ephemerons (ctx);
1697 * We clear togglerefs only after all possible chances of revival are done.
1698 * This is semantically more inline with what users expect and it allows for
1699 * user finalizers to correctly interact with TR objects.
1701 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1704 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1707 * handle disappearing links
1708 * Note we do this after checking the finalization queue because if an object
1709 * survives (at least long enough to be finalized) we don't clear the link.
1710 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1711 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1714 g_assert (sgen_gray_object_queue_is_empty (queue));
1716 sgen_null_link_in_range (generation, FALSE, ctx);
1717 if (generation == GENERATION_OLD)
1718 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1719 if (sgen_gray_object_queue_is_empty (queue))
1721 sgen_drain_gray_stack (-1, ctx);
1724 g_assert (sgen_gray_object_queue_is_empty (queue));
1726 sgen_gray_object_queue_trim_free_list (queue);
1730 sgen_check_section_scan_starts (GCMemSection *section)
1733 for (i = 0; i < section->num_scan_start; ++i) {
1734 if (section->scan_starts [i]) {
1735 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1736 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1742 check_scan_starts (void)
1744 if (!do_scan_starts_check)
1746 sgen_check_section_scan_starts (nursery_section);
1747 major_collector.check_scan_starts ();
1751 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1755 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1756 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1757 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1758 } SGEN_HASH_TABLE_FOREACH_END;
1762 sgen_dump_occupied (char *start, char *end, char *section_start)
1764 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1768 sgen_dump_section (GCMemSection *section, const char *type)
1770 char *start = section->data;
1771 char *end = section->data + section->size;
1772 char *occ_start = NULL;
1774 char *old_start G_GNUC_UNUSED = NULL; /* just for debugging */
1776 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1778 while (start < end) {
1780 MonoClass *class G_GNUC_UNUSED;
1782 if (!*(void**)start) {
1784 sgen_dump_occupied (occ_start, start, section->data);
1787 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1790 g_assert (start < section->next_data);
1795 vt = (GCVTable*)LOAD_VTABLE (start);
1798 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1801 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1802 start - section->data,
1803 vt->klass->name_space, vt->klass->name,
1811 sgen_dump_occupied (occ_start, start, section->data);
1813 fprintf (heap_dump_file, "</section>\n");
1817 dump_object (MonoObject *obj, gboolean dump_location)
1819 static char class_name [1024];
1821 MonoClass *class = mono_object_class (obj);
1825 * Python's XML parser is too stupid to parse angle brackets
1826 * in strings, so we just ignore them;
1829 while (class->name [i] && j < sizeof (class_name) - 1) {
1830 if (!strchr ("<>\"", class->name [i]))
1831 class_name [j++] = class->name [i];
1834 g_assert (j < sizeof (class_name));
1837 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1838 class->name_space, class_name,
1839 safe_object_get_size (obj));
1840 if (dump_location) {
1841 const char *location;
1842 if (ptr_in_nursery (obj))
1843 location = "nursery";
1844 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1848 fprintf (heap_dump_file, " location=\"%s\"", location);
1850 fprintf (heap_dump_file, "/>\n");
1854 dump_heap (const char *type, int num, const char *reason)
1859 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1861 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1862 fprintf (heap_dump_file, ">\n");
1863 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1864 sgen_dump_internal_mem_usage (heap_dump_file);
1865 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1866 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1867 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1869 fprintf (heap_dump_file, "<pinned-objects>\n");
1870 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1871 dump_object (list->obj, TRUE);
1872 fprintf (heap_dump_file, "</pinned-objects>\n");
1874 sgen_dump_section (nursery_section, "nursery");
1876 major_collector.dump_heap (heap_dump_file);
1878 fprintf (heap_dump_file, "<los>\n");
1879 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1880 dump_object ((MonoObject*)bigobj->data, FALSE);
1881 fprintf (heap_dump_file, "</los>\n");
1883 fprintf (heap_dump_file, "</collection>\n");
1887 sgen_register_moved_object (void *obj, void *destination)
1889 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1891 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1892 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1893 moved_objects_idx = 0;
1895 moved_objects [moved_objects_idx++] = obj;
1896 moved_objects [moved_objects_idx++] = destination;
1902 static gboolean inited = FALSE;
1907 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1909 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1910 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1911 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1912 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1913 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1914 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1915 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1916 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1918 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1919 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1920 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1921 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1922 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1923 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1924 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1925 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1926 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1927 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1928 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1929 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1930 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1932 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1934 #ifdef HEAVY_STATISTICS
1935 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1936 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1937 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1938 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1939 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1940 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1941 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1942 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1943 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1945 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1946 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1948 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1949 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1950 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1951 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1953 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1954 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1956 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1958 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1959 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1960 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1961 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1963 sgen_nursery_allocator_init_heavy_stats ();
1964 sgen_alloc_init_heavy_stats ();
1972 reset_pinned_from_failed_allocation (void)
1974 bytes_pinned_from_failed_allocation = 0;
1978 sgen_set_pinned_from_failed_allocation (mword objsize)
1980 bytes_pinned_from_failed_allocation += objsize;
1984 sgen_collection_is_concurrent (void)
1986 switch (current_collection_generation) {
1987 case GENERATION_NURSERY:
1989 case GENERATION_OLD:
1990 return concurrent_collection_in_progress;
1992 g_error ("Invalid current generation %d", current_collection_generation);
1997 sgen_concurrent_collection_in_progress (void)
1999 return concurrent_collection_in_progress;
2003 job_remembered_set_scan (WorkerData *worker_data, void *dummy)
2005 remset.scan_remsets (sgen_workers_get_job_gray_queue (worker_data));
2010 CopyOrMarkObjectFunc copy_or_mark_func;
2011 ScanObjectFunc scan_func;
2015 } ScanFromRegisteredRootsJobData;
2018 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2020 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2021 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2022 sgen_workers_get_job_gray_queue (worker_data) };
2024 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2025 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2032 } ScanThreadDataJobData;
2035 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2037 ScanThreadDataJobData *job_data = job_data_untyped;
2039 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2040 sgen_workers_get_job_gray_queue (worker_data));
2041 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2045 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2047 FinalizeReadyEntry *list = job_data_untyped;
2048 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2050 scan_finalizer_entries (list, ctx);
2054 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2056 g_assert (concurrent_collection_in_progress);
2057 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2061 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2063 g_assert (concurrent_collection_in_progress);
2064 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2068 verify_scan_starts (char *start, char *end)
2072 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2073 char *addr = nursery_section->scan_starts [i];
2074 if (addr > start && addr < end)
2075 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2080 verify_nursery (void)
2082 char *start, *end, *cur, *hole_start;
2084 if (!do_verify_nursery)
2087 if (nursery_canaries_enabled ())
2088 SGEN_LOG (1, "Checking nursery canaries...");
2090 /*This cleans up unused fragments */
2091 sgen_nursery_allocator_prepare_for_pinning ();
2093 hole_start = start = cur = sgen_get_nursery_start ();
2094 end = sgen_get_nursery_end ();
2099 if (!*(void**)cur) {
2100 cur += sizeof (void*);
2104 if (object_is_forwarded (cur))
2105 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2106 else if (object_is_pinned (cur))
2107 SGEN_LOG (1, "PINNED OBJ %p", cur);
2109 ss = safe_object_get_size ((MonoObject*)cur);
2110 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2111 verify_scan_starts (cur, cur + size);
2112 if (do_dump_nursery_content) {
2113 if (cur > hole_start)
2114 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2115 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 ());
2117 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2118 CHECK_CANARY_FOR_OBJECT (cur);
2119 CANARIFY_SIZE (size);
2127 * Checks that no objects in the nursery are fowarded or pinned. This
2128 * is a precondition to restarting the mutator while doing a
2129 * concurrent collection. Note that we don't clear fragments because
2130 * we depend on that having happened earlier.
2133 check_nursery_is_clean (void)
2137 cur = sgen_get_nursery_start ();
2138 end = sgen_get_nursery_end ();
2143 if (!*(void**)cur) {
2144 cur += sizeof (void*);
2148 g_assert (!object_is_forwarded (cur));
2149 g_assert (!object_is_pinned (cur));
2151 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2152 verify_scan_starts (cur, cur + size);
2159 init_gray_queue (void)
2161 if (sgen_collection_is_concurrent ())
2162 sgen_workers_init_distribute_gray_queue ();
2163 sgen_gray_object_queue_init (&gray_queue, NULL);
2167 * Perform a nursery collection.
2169 * Return whether any objects were late-pinned due to being out of memory.
2172 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2174 gboolean needs_major;
2175 size_t max_garbage_amount;
2177 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2178 ScanThreadDataJobData *stdjd;
2179 mword fragment_total;
2180 ScanCopyContext ctx;
2184 if (disable_minor_collections)
2187 TV_GETTIME (last_minor_collection_start_tv);
2188 atv = last_minor_collection_start_tv;
2190 MONO_GC_BEGIN (GENERATION_NURSERY);
2191 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2195 #ifndef DISABLE_PERFCOUNTERS
2196 mono_perfcounters->gc_collections0++;
2199 current_collection_generation = GENERATION_NURSERY;
2200 current_object_ops = sgen_minor_collector.serial_ops;
2202 reset_pinned_from_failed_allocation ();
2204 check_scan_starts ();
2206 sgen_nursery_alloc_prepare_for_minor ();
2210 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2211 /* FIXME: optimize later to use the higher address where an object can be present */
2212 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2214 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 ()));
2215 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2216 g_assert (nursery_section->size >= max_garbage_amount);
2218 /* world must be stopped already */
2220 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2222 if (xdomain_checks) {
2223 sgen_clear_nursery_fragments ();
2224 sgen_check_for_xdomain_refs ();
2227 nursery_section->next_data = nursery_next;
2229 major_collector.start_nursery_collection ();
2231 sgen_memgov_minor_collection_start ();
2235 gc_stats.minor_gc_count ++;
2237 if (whole_heap_check_before_collection) {
2238 sgen_clear_nursery_fragments ();
2239 sgen_check_whole_heap (finish_up_concurrent_mark);
2241 if (consistency_check_at_minor_collection)
2242 sgen_check_consistency ();
2244 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2246 sgen_process_fin_stage_entries ();
2247 sgen_process_dislink_stage_entries ();
2249 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2251 /* pin from pinned handles */
2252 sgen_init_pinning ();
2253 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2254 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2255 /* pin cemented objects */
2256 sgen_pin_cemented_objects ();
2257 /* identify pinned objects */
2258 sgen_optimize_pin_queue ();
2259 sgen_pinning_setup_section (nursery_section);
2260 ctx.scan_func = NULL;
2261 ctx.copy_func = NULL;
2262 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2263 pin_objects_in_nursery (ctx);
2264 sgen_pinning_trim_queue_to_section (nursery_section);
2267 time_minor_pinning += TV_ELAPSED (btv, atv);
2268 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2269 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2271 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2274 * FIXME: When we finish a concurrent collection we do a nursery collection first,
2275 * as part of which we scan the card table. Then, later, we scan the mod union
2276 * cardtable. We should only have to do one.
2278 sgen_workers_enqueue_job ("scan remset", job_remembered_set_scan, NULL);
2280 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2282 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2283 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2285 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2287 /* FIXME: why is this here? */
2288 ctx.scan_func = current_object_ops.scan_object;
2289 ctx.copy_func = NULL;
2290 ctx.queue = &gray_queue;
2291 sgen_drain_gray_stack (-1, ctx);
2293 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2294 report_registered_roots ();
2295 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2296 report_finalizer_roots ();
2298 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2300 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2302 /* registered roots, this includes static fields */
2303 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2304 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2305 scrrjd_normal->scan_func = current_object_ops.scan_object;
2306 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2307 scrrjd_normal->heap_end = nursery_next;
2308 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2309 sgen_workers_enqueue_job ("scan from registered roots normal", job_scan_from_registered_roots, scrrjd_normal);
2311 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2312 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2313 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2314 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2315 scrrjd_wbarrier->heap_end = nursery_next;
2316 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2317 sgen_workers_enqueue_job ("scan from registered roots wbarrier", job_scan_from_registered_roots, scrrjd_wbarrier);
2320 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2322 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2325 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2326 stdjd->heap_start = sgen_get_nursery_start ();
2327 stdjd->heap_end = nursery_next;
2328 sgen_workers_enqueue_job ("scan thread data", job_scan_thread_data, stdjd);
2331 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2334 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2336 g_assert (!sgen_collection_is_concurrent ());
2338 /* Scan the list of objects ready for finalization. If */
2339 sgen_workers_enqueue_job ("scan finalizer entries", job_scan_finalizer_entries, fin_ready_list);
2340 sgen_workers_enqueue_job ("scan criticial finalizer entries", job_scan_finalizer_entries, critical_fin_list);
2342 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2344 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2346 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2347 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2349 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2352 * The (single-threaded) finalization code might have done
2353 * some copying/marking so we can only reset the GC thread's
2354 * worker data here instead of earlier when we joined the
2357 sgen_workers_reset_data ();
2359 if (objects_pinned) {
2360 sgen_optimize_pin_queue ();
2361 sgen_pinning_setup_section (nursery_section);
2364 /* walk the pin_queue, build up the fragment list of free memory, unmark
2365 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2368 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2369 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2370 if (!fragment_total)
2373 /* Clear TLABs for all threads */
2374 sgen_clear_tlabs ();
2376 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2378 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2379 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2381 if (consistency_check_at_minor_collection)
2382 sgen_check_major_refs ();
2384 major_collector.finish_nursery_collection ();
2386 TV_GETTIME (last_minor_collection_end_tv);
2387 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2390 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2392 /* prepare the pin queue for the next collection */
2393 sgen_finish_pinning ();
2394 if (fin_ready_list || critical_fin_list) {
2395 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2396 mono_gc_finalize_notify ();
2398 sgen_pin_stats_reset ();
2399 /* clear cemented hash */
2400 sgen_cement_clear_below_threshold ();
2402 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2404 remset.finish_minor_collection ();
2406 check_scan_starts ();
2408 binary_protocol_flush_buffers (FALSE);
2410 sgen_memgov_minor_collection_end ();
2412 /*objects are late pinned because of lack of memory, so a major is a good call*/
2413 needs_major = objects_pinned > 0;
2414 current_collection_generation = -1;
2417 MONO_GC_END (GENERATION_NURSERY);
2418 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
2420 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2421 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2427 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2430 * This is called on all objects in the nursery, including pinned ones, so we need
2431 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2433 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2437 scan_nursery_objects (ScanCopyContext ctx)
2439 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2440 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2444 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)
2449 /* FIXME: only use these values for the precise scan
2450 * note that to_space pointers should be excluded anyway...
2452 char *heap_start = NULL;
2453 char *heap_end = (char*)-1;
2454 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2455 GCRootReport root_report = { 0 };
2456 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2457 ScanThreadDataJobData *stdjd;
2458 ScanCopyContext ctx;
2460 if (concurrent_collection_in_progress) {
2461 /*This cleans up unused fragments */
2462 sgen_nursery_allocator_prepare_for_pinning ();
2464 if (do_concurrent_checks)
2465 check_nursery_is_clean ();
2467 /* The concurrent collector doesn't touch the nursery. */
2468 sgen_nursery_alloc_prepare_for_major ();
2475 /* Pinning depends on this */
2476 sgen_clear_nursery_fragments ();
2478 if (whole_heap_check_before_collection)
2479 sgen_check_whole_heap (finish_up_concurrent_mark);
2482 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2484 if (!sgen_collection_is_concurrent ())
2485 nursery_section->next_data = sgen_get_nursery_end ();
2486 /* we should also coalesce scanning from sections close to each other
2487 * and deal with pointers outside of the sections later.
2492 if (xdomain_checks) {
2493 sgen_clear_nursery_fragments ();
2494 sgen_check_for_xdomain_refs ();
2497 if (!concurrent_collection_in_progress) {
2498 /* Remsets are not useful for a major collection */
2499 remset.clear_cards ();
2502 sgen_process_fin_stage_entries ();
2503 sgen_process_dislink_stage_entries ();
2506 sgen_init_pinning ();
2507 SGEN_LOG (6, "Collecting pinned addresses");
2508 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2510 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2511 if (major_collector.is_concurrent) {
2513 * The concurrent major collector cannot evict
2514 * yet, so we need to pin cemented objects to
2515 * not break some asserts.
2517 * FIXME: We could evict now!
2519 sgen_pin_cemented_objects ();
2523 sgen_optimize_pin_queue ();
2526 * pin_queue now contains all candidate pointers, sorted and
2527 * uniqued. We must do two passes now to figure out which
2528 * objects are pinned.
2530 * The first is to find within the pin_queue the area for each
2531 * section. This requires that the pin_queue be sorted. We
2532 * also process the LOS objects and pinned chunks here.
2534 * The second, destructive, pass is to reduce the section
2535 * areas to pointers to the actually pinned objects.
2537 SGEN_LOG (6, "Pinning from sections");
2538 /* first pass for the sections */
2539 sgen_find_section_pin_queue_start_end (nursery_section);
2540 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2541 /* identify possible pointers to the insize of large objects */
2542 SGEN_LOG (6, "Pinning from large objects");
2543 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2545 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2546 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2548 #ifdef ENABLE_DTRACE
2549 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2550 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2551 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2555 if (sgen_los_object_is_pinned (bigobj->data)) {
2556 g_assert (finish_up_concurrent_mark);
2559 sgen_los_pin_object (bigobj->data);
2560 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2561 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2562 if (G_UNLIKELY (do_pin_stats))
2563 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2564 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));
2567 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2571 notify_gc_roots (&root_report);
2572 /* second pass for the sections */
2573 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2574 ctx.copy_func = NULL;
2575 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2578 * Concurrent mark never follows references into the nursery. In the start and
2579 * finish pauses we must scan live nursery objects, though.
2581 * In the finish pause we do this conservatively by scanning all nursery objects.
2582 * Previously we would only scan pinned objects here. We assumed that all objects
2583 * that were pinned during the nursery collection immediately preceding this finish
2584 * mark would be pinned again here. Due to the way we get the stack end for the GC
2585 * thread, however, that's not necessarily the case: we scan part of the stack used
2586 * by the GC itself, which changes constantly, so pinning isn't entirely
2589 * The split nursery also complicates things because non-pinned objects can survive
2590 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2592 * In the future we shouldn't do a preceding nursery collection at all and instead
2593 * do the finish pause with promotion from the nursery.
2595 * A further complication arises when we have late-pinned objects from the preceding
2596 * nursery collection. Those are the result of being out of memory when trying to
2597 * evacuate objects. They won't be found from the roots, so we just scan the whole
2600 * Non-concurrent mark evacuates from the nursery, so it's
2601 * sufficient to just scan pinned nursery objects.
2603 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2604 scan_nursery_objects (ctx);
2606 pin_objects_in_nursery (ctx);
2607 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2608 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2611 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2612 if (old_next_pin_slot)
2613 *old_next_pin_slot = sgen_get_pinned_count ();
2616 time_major_pinning += TV_ELAPSED (atv, btv);
2617 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2618 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2620 major_collector.init_to_space ();
2623 * The concurrent collector doesn't move objects, neither on
2624 * the major heap nor in the nursery, so we can mark even
2625 * before pinning has finished. For the non-concurrent
2626 * collector we start the workers after pinning.
2628 if (start_concurrent_mark) {
2629 sgen_workers_start_all_workers ();
2630 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2633 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2634 main_gc_thread = mono_native_thread_self ();
2637 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2638 report_registered_roots ();
2640 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2642 /* registered roots, this includes static fields */
2643 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2644 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2645 scrrjd_normal->scan_func = current_object_ops.scan_object;
2646 scrrjd_normal->heap_start = heap_start;
2647 scrrjd_normal->heap_end = heap_end;
2648 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2649 sgen_workers_enqueue_job ("scan from registered roots normal", job_scan_from_registered_roots, scrrjd_normal);
2651 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2652 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2653 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2654 scrrjd_wbarrier->heap_start = heap_start;
2655 scrrjd_wbarrier->heap_end = heap_end;
2656 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2657 sgen_workers_enqueue_job ("scan from registered roots wbarrier", job_scan_from_registered_roots, scrrjd_wbarrier);
2660 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2663 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2664 stdjd->heap_start = heap_start;
2665 stdjd->heap_end = heap_end;
2666 sgen_workers_enqueue_job ("scan thread data", job_scan_thread_data, stdjd);
2669 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2672 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2674 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2675 report_finalizer_roots ();
2677 /* scan the list of objects ready for finalization */
2678 sgen_workers_enqueue_job ("scan finalizer entries", job_scan_finalizer_entries, fin_ready_list);
2679 sgen_workers_enqueue_job ("scan critical finalizer entries", job_scan_finalizer_entries, critical_fin_list);
2681 if (scan_mod_union) {
2682 g_assert (finish_up_concurrent_mark);
2684 /* Mod union card table */
2685 sgen_workers_enqueue_job ("scan mod union cardtable", job_scan_major_mod_union_cardtable, NULL);
2686 sgen_workers_enqueue_job ("scan LOS mod union cardtable", job_scan_los_mod_union_cardtable, NULL);
2690 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2691 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2694 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2698 major_finish_copy_or_mark (void)
2700 if (!concurrent_collection_in_progress)
2704 * Prepare the pin queue for the next collection. Since pinning runs on the worker
2705 * threads we must wait for the jobs to finish before we can reset it.
2707 sgen_workers_wait_for_jobs_finished ();
2708 sgen_finish_pinning ();
2710 sgen_pin_stats_reset ();
2712 if (do_concurrent_checks)
2713 check_nursery_is_clean ();
2717 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2719 MONO_GC_BEGIN (GENERATION_OLD);
2720 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2722 current_collection_generation = GENERATION_OLD;
2723 #ifndef DISABLE_PERFCOUNTERS
2724 mono_perfcounters->gc_collections1++;
2727 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2729 sgen_cement_reset ();
2732 g_assert (major_collector.is_concurrent);
2733 concurrent_collection_in_progress = TRUE;
2735 current_object_ops = major_collector.major_concurrent_ops;
2737 current_object_ops = major_collector.major_ops;
2740 reset_pinned_from_failed_allocation ();
2742 sgen_memgov_major_collection_start ();
2744 //count_ref_nonref_objs ();
2745 //consistency_check ();
2747 check_scan_starts ();
2750 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2751 gc_stats.major_gc_count ++;
2753 if (major_collector.start_major_collection)
2754 major_collector.start_major_collection ();
2756 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent, FALSE, FALSE, FALSE);
2757 major_finish_copy_or_mark ();
2761 wait_for_workers_to_finish (void)
2763 while (!sgen_workers_all_done ())
2768 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_whole_nursery)
2770 ScannedObjectCounts counts;
2771 LOSObject *bigobj, *prevbo;
2777 if (concurrent_collection_in_progress) {
2778 sgen_workers_signal_start_nursery_collection_and_wait ();
2780 current_object_ops = major_collector.major_concurrent_ops;
2782 major_copy_or_mark_from_roots (NULL, FALSE, TRUE, TRUE, scan_whole_nursery);
2784 sgen_workers_signal_finish_nursery_collection ();
2786 major_finish_copy_or_mark ();
2787 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2789 sgen_workers_join ();
2791 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2793 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2794 main_gc_thread = NULL;
2797 if (do_concurrent_checks)
2798 check_nursery_is_clean ();
2800 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2801 current_object_ops = major_collector.major_ops;
2805 * The workers have stopped so we need to finish gray queue
2806 * work that might result from finalization in the main GC
2807 * thread. Redirection must therefore be turned off.
2809 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2810 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2812 /* all the objects in the heap */
2813 finish_gray_stack (GENERATION_OLD, &gray_queue);
2815 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2817 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2820 * The (single-threaded) finalization code might have done
2821 * some copying/marking so we can only reset the GC thread's
2822 * worker data here instead of earlier when we joined the
2825 sgen_workers_reset_data ();
2827 if (objects_pinned) {
2828 g_assert (!concurrent_collection_in_progress);
2831 * This is slow, but we just OOM'd.
2833 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2834 * queue is laid out at this point.
2836 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2838 * We need to reestablish all pinned nursery objects in the pin queue
2839 * because they're needed for fragment creation. Unpinning happens by
2840 * walking the whole queue, so it's not necessary to reestablish where major
2841 * heap block pins are - all we care is that they're still in there
2844 sgen_optimize_pin_queue ();
2845 sgen_find_section_pin_queue_start_end (nursery_section);
2849 reset_heap_boundaries ();
2850 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2852 if (!concurrent_collection_in_progress) {
2853 /* walk the pin_queue, build up the fragment list of free memory, unmark
2854 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2857 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2860 /* prepare the pin queue for the next collection */
2861 sgen_finish_pinning ();
2863 /* Clear TLABs for all threads */
2864 sgen_clear_tlabs ();
2866 sgen_pin_stats_reset ();
2869 sgen_cement_clear_below_threshold ();
2871 if (check_mark_bits_after_major_collection)
2872 sgen_check_heap_marked (concurrent_collection_in_progress);
2875 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2878 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2880 /* sweep the big objects list */
2882 for (bigobj = los_object_list; bigobj;) {
2883 g_assert (!object_is_pinned (bigobj->data));
2884 if (sgen_los_object_is_pinned (bigobj->data)) {
2885 sgen_los_unpin_object (bigobj->data);
2886 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2889 /* not referenced anywhere, so we can free it */
2891 prevbo->next = bigobj->next;
2893 los_object_list = bigobj->next;
2895 bigobj = bigobj->next;
2896 sgen_los_free_object (to_free);
2900 bigobj = bigobj->next;
2904 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2909 time_major_los_sweep += TV_ELAPSED (atv, btv);
2911 major_collector.sweep ();
2913 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2916 time_major_sweep += TV_ELAPSED (btv, atv);
2919 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2921 if (fin_ready_list || critical_fin_list) {
2922 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2923 mono_gc_finalize_notify ();
2926 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2928 sgen_memgov_major_collection_end ();
2929 current_collection_generation = -1;
2931 memset (&counts, 0, sizeof (ScannedObjectCounts));
2932 major_collector.finish_major_collection (&counts);
2934 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2936 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2937 if (concurrent_collection_in_progress)
2938 concurrent_collection_in_progress = FALSE;
2940 check_scan_starts ();
2942 binary_protocol_flush_buffers (FALSE);
2944 //consistency_check ();
2946 MONO_GC_END (GENERATION_OLD);
2947 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2951 major_do_collection (const char *reason)
2953 TV_DECLARE (time_start);
2954 TV_DECLARE (time_end);
2955 size_t old_next_pin_slot;
2957 if (disable_major_collections)
2960 if (major_collector.get_and_reset_num_major_objects_marked) {
2961 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2962 g_assert (!num_marked);
2965 /* world must be stopped already */
2966 TV_GETTIME (time_start);
2968 major_start_collection (FALSE, &old_next_pin_slot);
2969 major_finish_collection (reason, old_next_pin_slot, FALSE);
2971 TV_GETTIME (time_end);
2972 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2974 /* FIXME: also report this to the user, preferably in gc-end. */
2975 if (major_collector.get_and_reset_num_major_objects_marked)
2976 major_collector.get_and_reset_num_major_objects_marked ();
2978 return bytes_pinned_from_failed_allocation > 0;
2982 major_start_concurrent_collection (const char *reason)
2984 TV_DECLARE (time_start);
2985 TV_DECLARE (time_end);
2986 long long num_objects_marked;
2988 if (disable_major_collections)
2991 TV_GETTIME (time_start);
2992 SGEN_TV_GETTIME (time_major_conc_collection_start);
2994 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2995 g_assert (num_objects_marked == 0);
2997 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
2998 binary_protocol_concurrent_start ();
3000 // FIXME: store reason and pass it when finishing
3001 major_start_collection (TRUE, NULL);
3003 gray_queue_redirect (&gray_queue);
3005 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3006 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3008 TV_GETTIME (time_end);
3009 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3011 current_collection_generation = -1;
3015 * Returns whether the major collection has finished.
3018 major_should_finish_concurrent_collection (void)
3020 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
3021 return sgen_workers_all_done ();
3025 major_update_concurrent_collection (void)
3027 TV_DECLARE (total_start);
3028 TV_DECLARE (total_end);
3030 TV_GETTIME (total_start);
3032 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3033 binary_protocol_concurrent_update ();
3035 major_collector.update_cardtable_mod_union ();
3036 sgen_los_update_cardtable_mod_union ();
3038 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3040 TV_GETTIME (total_end);
3041 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3045 major_finish_concurrent_collection (void)
3047 TV_DECLARE (total_start);
3048 TV_DECLARE (total_end);
3049 gboolean late_pinned;
3050 SgenGrayQueue unpin_queue;
3051 memset (&unpin_queue, 0, sizeof (unpin_queue));
3053 TV_GETTIME (total_start);
3055 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3056 binary_protocol_concurrent_finish ();
3059 * The major collector can add global remsets which are processed in the finishing
3060 * nursery collection, below. That implies that the workers must have finished
3061 * marking before the nursery collection is allowed to run, otherwise we might miss
3064 wait_for_workers_to_finish ();
3066 SGEN_TV_GETTIME (time_major_conc_collection_end);
3067 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3069 major_collector.update_cardtable_mod_union ();
3070 sgen_los_update_cardtable_mod_union ();
3072 late_pinned = collect_nursery (&unpin_queue, TRUE);
3074 if (mod_union_consistency_check)
3075 sgen_check_mod_union_consistency ();
3077 current_collection_generation = GENERATION_OLD;
3078 major_finish_collection ("finishing", -1, late_pinned);
3080 if (whole_heap_check_before_collection)
3081 sgen_check_whole_heap (FALSE);
3083 unpin_objects_from_queue (&unpin_queue);
3084 sgen_gray_object_queue_deinit (&unpin_queue);
3086 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3088 TV_GETTIME (total_end);
3089 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3091 current_collection_generation = -1;
3095 * Ensure an allocation request for @size will succeed by freeing enough memory.
3097 * LOCKING: The GC lock MUST be held.
3100 sgen_ensure_free_space (size_t size)
3102 int generation_to_collect = -1;
3103 const char *reason = NULL;
3106 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3107 if (sgen_need_major_collection (size)) {
3108 reason = "LOS overflow";
3109 generation_to_collect = GENERATION_OLD;
3112 if (degraded_mode) {
3113 if (sgen_need_major_collection (size)) {
3114 reason = "Degraded mode overflow";
3115 generation_to_collect = GENERATION_OLD;
3117 } else if (sgen_need_major_collection (size)) {
3118 reason = "Minor allowance";
3119 generation_to_collect = GENERATION_OLD;
3121 generation_to_collect = GENERATION_NURSERY;
3122 reason = "Nursery full";
3126 if (generation_to_collect == -1) {
3127 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3128 generation_to_collect = GENERATION_OLD;
3129 reason = "Finish concurrent collection";
3133 if (generation_to_collect == -1)
3135 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3139 * LOCKING: Assumes the GC lock is held.
3142 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3144 TV_DECLARE (gc_start);
3145 TV_DECLARE (gc_end);
3146 TV_DECLARE (gc_total_start);
3147 TV_DECLARE (gc_total_end);
3148 GGTimingInfo infos [2];
3149 int overflow_generation_to_collect = -1;
3150 int oldest_generation_collected = generation_to_collect;
3151 const char *overflow_reason = NULL;
3153 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3155 binary_protocol_collection_force (generation_to_collect);
3157 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3159 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3161 TV_GETTIME (gc_start);
3163 sgen_stop_world (generation_to_collect);
3165 TV_GETTIME (gc_total_start);
3167 if (concurrent_collection_in_progress) {
3169 * We update the concurrent collection. If it finished, we're done. If
3170 * not, and we've been asked to do a nursery collection, we do that.
3172 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3175 major_finish_concurrent_collection ();
3176 oldest_generation_collected = GENERATION_OLD;
3178 sgen_workers_signal_start_nursery_collection_and_wait ();
3180 major_update_concurrent_collection ();
3181 if (generation_to_collect == GENERATION_NURSERY)
3182 collect_nursery (NULL, FALSE);
3184 sgen_workers_signal_finish_nursery_collection ();
3191 * If we've been asked to do a major collection, and the major collector wants to
3192 * run synchronously (to evacuate), we set the flag to do that.
3194 if (generation_to_collect == GENERATION_OLD &&
3195 allow_synchronous_major &&
3196 major_collector.want_synchronous_collection &&
3197 *major_collector.want_synchronous_collection) {
3198 wait_to_finish = TRUE;
3201 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3204 * There's no concurrent collection in progress. Collect the generation we're asked
3205 * to collect. If the major collector is concurrent and we're not forced to wait,
3206 * start a concurrent collection.
3208 // FIXME: extract overflow reason
3209 if (generation_to_collect == GENERATION_NURSERY) {
3210 if (collect_nursery (NULL, FALSE)) {
3211 overflow_generation_to_collect = GENERATION_OLD;
3212 overflow_reason = "Minor overflow";
3215 if (major_collector.is_concurrent && !wait_to_finish) {
3216 collect_nursery (NULL, FALSE);
3217 major_start_concurrent_collection (reason);
3218 // FIXME: set infos[0] properly
3222 if (major_do_collection (reason)) {
3223 overflow_generation_to_collect = GENERATION_NURSERY;
3224 overflow_reason = "Excessive pinning";
3228 TV_GETTIME (gc_end);
3230 memset (infos, 0, sizeof (infos));
3231 infos [0].generation = generation_to_collect;
3232 infos [0].reason = reason;
3233 infos [0].is_overflow = FALSE;
3234 infos [1].generation = -1;
3235 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3237 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3239 if (overflow_generation_to_collect != -1) {
3241 * We need to do an overflow collection, either because we ran out of memory
3242 * or the nursery is fully pinned.
3245 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3246 infos [1].generation = overflow_generation_to_collect;
3247 infos [1].reason = overflow_reason;
3248 infos [1].is_overflow = TRUE;
3249 infos [1].total_time = gc_end;
3251 if (overflow_generation_to_collect == GENERATION_NURSERY)
3252 collect_nursery (NULL, FALSE);
3254 major_do_collection (overflow_reason);
3256 TV_GETTIME (gc_end);
3257 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3259 /* keep events symmetric */
3260 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3262 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3265 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3267 /* this also sets the proper pointers for the next allocation */
3268 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3269 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3270 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3271 sgen_dump_pin_queue ();
3276 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3278 TV_GETTIME (gc_total_end);
3279 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3281 sgen_restart_world (oldest_generation_collected, infos);
3283 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3287 * ######################################################################
3288 * ######## Memory allocation from the OS
3289 * ######################################################################
3290 * This section of code deals with getting memory from the OS and
3291 * allocating memory for GC-internal data structures.
3292 * Internal memory can be handled with a freelist for small objects.
3298 G_GNUC_UNUSED static void
3299 report_internal_mem_usage (void)
3301 printf ("Internal memory usage:\n");
3302 sgen_report_internal_mem_usage ();
3303 printf ("Pinned memory usage:\n");
3304 major_collector.report_pinned_memory_usage ();
3308 * ######################################################################
3309 * ######## Finalization support
3310 * ######################################################################
3313 static inline gboolean
3314 sgen_major_is_object_alive (void *object)
3318 /* Oldgen objects can be pinned and forwarded too */
3319 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3323 * FIXME: major_collector.is_object_live() also calculates the
3324 * size. Avoid the double calculation.
3326 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3327 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3328 return sgen_los_object_is_pinned (object);
3330 return major_collector.is_object_live (object);
3334 * If the object has been forwarded it means it's still referenced from a root.
3335 * If it is pinned it's still alive as well.
3336 * A LOS object is only alive if we have pinned it.
3337 * Return TRUE if @obj is ready to be finalized.
3339 static inline gboolean
3340 sgen_is_object_alive (void *object)
3342 if (ptr_in_nursery (object))
3343 return sgen_nursery_is_object_alive (object);
3345 return sgen_major_is_object_alive (object);
3349 * This function returns true if @object is either alive or it belongs to the old gen
3350 * and we're currently doing a minor collection.
3353 sgen_is_object_alive_for_current_gen (char *object)
3355 if (ptr_in_nursery (object))
3356 return sgen_nursery_is_object_alive (object);
3358 if (current_collection_generation == GENERATION_NURSERY)
3361 return sgen_major_is_object_alive (object);
3365 * This function returns true if @object is either alive and belongs to the
3366 * current collection - major collections are full heap, so old gen objects
3367 * are never alive during a minor collection.
3370 sgen_is_object_alive_and_on_current_collection (char *object)
3372 if (ptr_in_nursery (object))
3373 return sgen_nursery_is_object_alive (object);
3375 if (current_collection_generation == GENERATION_NURSERY)
3378 return sgen_major_is_object_alive (object);
3383 sgen_gc_is_object_ready_for_finalization (void *object)
3385 return !sgen_is_object_alive (object);
3389 has_critical_finalizer (MonoObject *obj)
3393 if (!mono_defaults.critical_finalizer_object)
3396 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3398 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3402 is_finalization_aware (MonoObject *obj)
3404 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3405 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3409 sgen_queue_finalization_entry (MonoObject *obj)
3411 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3412 gboolean critical = has_critical_finalizer (obj);
3413 entry->object = obj;
3415 entry->next = critical_fin_list;
3416 critical_fin_list = entry;
3418 entry->next = fin_ready_list;
3419 fin_ready_list = entry;
3422 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3423 fin_callbacks.object_queued_for_finalization (obj);
3425 #ifdef ENABLE_DTRACE
3426 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3427 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3428 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3429 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3430 vt->klass->name_space, vt->klass->name, gen, critical);
3436 sgen_object_is_live (void *obj)
3438 return sgen_is_object_alive_and_on_current_collection (obj);
3441 /* LOCKING: requires that the GC lock is held */
3443 null_ephemerons_for_domain (MonoDomain *domain)
3445 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3448 MonoObject *object = (MonoObject*)current->array;
3451 SGEN_ASSERT (0, object->vtable, "Can't have objects without vtables.");
3453 if (object && object->vtable->domain == domain) {
3454 EphemeronLinkNode *tmp = current;
3457 prev->next = current->next;
3459 ephemeron_list = current->next;
3461 current = current->next;
3462 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3465 current = current->next;
3470 /* LOCKING: requires that the GC lock is held */
3472 clear_unreachable_ephemerons (ScanCopyContext ctx)
3474 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3475 GrayQueue *queue = ctx.queue;
3476 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3478 Ephemeron *cur, *array_end;
3482 char *object = current->array;
3484 if (!sgen_is_object_alive_for_current_gen (object)) {
3485 EphemeronLinkNode *tmp = current;
3487 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3490 prev->next = current->next;
3492 ephemeron_list = current->next;
3494 current = current->next;
3495 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3500 copy_func ((void**)&object, queue);
3501 current->array = object;
3503 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3505 array = (MonoArray*)object;
3506 cur = mono_array_addr (array, Ephemeron, 0);
3507 array_end = cur + mono_array_length_fast (array);
3508 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3510 for (; cur < array_end; ++cur) {
3511 char *key = (char*)cur->key;
3513 if (!key || key == tombstone)
3516 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3517 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3518 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3520 if (!sgen_is_object_alive_for_current_gen (key)) {
3521 cur->key = tombstone;
3527 current = current->next;
3532 LOCKING: requires that the GC lock is held
3534 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3537 mark_ephemerons_in_range (ScanCopyContext ctx)
3539 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3540 GrayQueue *queue = ctx.queue;
3541 int nothing_marked = 1;
3542 EphemeronLinkNode *current = ephemeron_list;
3544 Ephemeron *cur, *array_end;
3547 for (current = ephemeron_list; current; current = current->next) {
3548 char *object = current->array;
3549 SGEN_LOG (5, "Ephemeron array at %p", object);
3551 /*It has to be alive*/
3552 if (!sgen_is_object_alive_for_current_gen (object)) {
3553 SGEN_LOG (5, "\tnot reachable");
3557 copy_func ((void**)&object, queue);
3559 array = (MonoArray*)object;
3560 cur = mono_array_addr (array, Ephemeron, 0);
3561 array_end = cur + mono_array_length_fast (array);
3562 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3564 for (; cur < array_end; ++cur) {
3565 char *key = cur->key;
3567 if (!key || key == tombstone)
3570 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3571 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3572 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3574 if (sgen_is_object_alive_for_current_gen (key)) {
3575 char *value = cur->value;
3577 copy_func ((void**)&cur->key, queue);
3579 if (!sgen_is_object_alive_for_current_gen (value))
3581 copy_func ((void**)&cur->value, queue);
3587 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3588 return nothing_marked;
3592 mono_gc_invoke_finalizers (void)
3594 FinalizeReadyEntry *entry = NULL;
3595 gboolean entry_is_critical = FALSE;
3598 /* FIXME: batch to reduce lock contention */
3599 while (fin_ready_list || critical_fin_list) {
3603 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3605 /* We have finalized entry in the last
3606 interation, now we need to remove it from
3609 *list = entry->next;
3611 FinalizeReadyEntry *e = *list;
3612 while (e->next != entry)
3614 e->next = entry->next;
3616 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3620 /* Now look for the first non-null entry. */
3621 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3624 entry_is_critical = FALSE;
3626 entry_is_critical = TRUE;
3627 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3632 g_assert (entry->object);
3633 num_ready_finalizers--;
3634 obj = entry->object;
3635 entry->object = NULL;
3636 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3644 g_assert (entry->object == NULL);
3646 /* the object is on the stack so it is pinned */
3647 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3648 mono_gc_run_finalize (obj, NULL);
3655 mono_gc_pending_finalizers (void)
3657 return fin_ready_list || critical_fin_list;
3661 * ######################################################################
3662 * ######## registered roots support
3663 * ######################################################################
3667 * We do not coalesce roots.
3670 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3672 RootRecord new_root;
3675 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3676 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3677 /* we allow changing the size and the descriptor (for thread statics etc) */
3679 size_t old_size = root->end_root - start;
3680 root->end_root = start + size;
3681 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3682 ((root->root_desc == 0) && (descr == NULL)));
3683 root->root_desc = (mword)descr;
3685 roots_size -= old_size;
3691 new_root.end_root = start + size;
3692 new_root.root_desc = (mword)descr;
3694 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3697 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);
3704 mono_gc_register_root (char *start, size_t size, void *descr)
3706 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3710 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3712 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3716 mono_gc_deregister_root (char* addr)
3722 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3723 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3724 roots_size -= (root.end_root - addr);
3730 * ######################################################################
3731 * ######## Thread handling (stop/start code)
3732 * ######################################################################
3735 unsigned int sgen_global_stop_count = 0;
3738 sgen_get_current_collection_generation (void)
3740 return current_collection_generation;
3744 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3746 gc_callbacks = *callbacks;
3750 mono_gc_get_gc_callbacks ()
3752 return &gc_callbacks;
3755 /* Variables holding start/end nursery so it won't have to be passed at every call */
3756 static void *scan_area_arg_start, *scan_area_arg_end;
3759 mono_gc_conservatively_scan_area (void *start, void *end)
3761 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3765 mono_gc_scan_object (void *obj, void *gc_data)
3767 UserCopyOrMarkData *data = gc_data;
3768 current_object_ops.copy_or_mark_object (&obj, data->queue);
3773 * Mark from thread stacks and registers.
3776 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3778 SgenThreadInfo *info;
3780 scan_area_arg_start = start_nursery;
3781 scan_area_arg_end = end_nursery;
3783 FOREACH_THREAD (info) {
3785 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);
3788 if (info->gc_disabled) {
3789 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);
3792 if (!mono_thread_info_is_live (info)) {
3793 SGEN_LOG (3, "Skipping non-running thread %p, range: %p-%p, size: %td (state %x)", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, info->info.thread_state);
3796 g_assert (info->suspend_done);
3797 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 ());
3798 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3799 UserCopyOrMarkData data = { NULL, queue };
3800 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3801 } else if (!precise) {
3802 if (!conservative_stack_mark) {
3803 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3804 conservative_stack_mark = TRUE;
3806 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3811 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3812 start_nursery, end_nursery, PIN_TYPE_STACK);
3814 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3815 start_nursery, end_nursery, PIN_TYPE_STACK);
3818 } END_FOREACH_THREAD
3822 ptr_on_stack (void *ptr)
3824 gpointer stack_start = &stack_start;
3825 SgenThreadInfo *info = mono_thread_info_current ();
3827 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3833 sgen_thread_register (SgenThreadInfo* info, void *addr)
3836 guint8 *staddr = NULL;
3838 #ifndef HAVE_KW_THREAD
3839 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3841 g_assert (!mono_native_tls_get_value (thread_info_key));
3842 mono_native_tls_set_value (thread_info_key, info);
3844 sgen_thread_info = info;
3847 #ifdef SGEN_POSIX_STW
3848 info->stop_count = -1;
3852 info->stack_start = NULL;
3853 info->stopped_ip = NULL;
3854 info->stopped_domain = NULL;
3856 memset (&info->ctx, 0, sizeof (MonoContext));
3858 memset (&info->regs, 0, sizeof (info->regs));
3861 sgen_init_tlab_info (info);
3863 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3865 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3866 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3869 info->stack_start_limit = staddr;
3871 info->stack_end = staddr + stsize;
3873 gsize stack_bottom = (gsize)addr;
3874 stack_bottom += 4095;
3875 stack_bottom &= ~4095;
3876 info->stack_end = (char*)stack_bottom;
3879 #ifdef HAVE_KW_THREAD
3880 stack_end = info->stack_end;
3883 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3885 if (gc_callbacks.thread_attach_func)
3886 info->runtime_data = gc_callbacks.thread_attach_func ();
3891 sgen_thread_detach (SgenThreadInfo *p)
3893 /* If a delegate is passed to native code and invoked on a thread we dont
3894 * know about, the jit will register it with mono_jit_thread_attach, but
3895 * we have no way of knowing when that thread goes away. SGen has a TSD
3896 * so we assume that if the domain is still registered, we can detach
3899 if (mono_domain_get ())
3900 mono_thread_detach_internal (mono_thread_internal_current ());
3904 sgen_thread_unregister (SgenThreadInfo *p)
3906 MonoNativeThreadId tid;
3908 tid = mono_thread_info_get_tid (p);
3909 binary_protocol_thread_unregister ((gpointer)tid);
3910 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3912 #ifndef HAVE_KW_THREAD
3913 mono_native_tls_set_value (thread_info_key, NULL);
3915 sgen_thread_info = NULL;
3918 if (p->info.runtime_thread)
3919 mono_threads_add_joinable_thread ((gpointer)tid);
3921 if (gc_callbacks.thread_detach_func) {
3922 gc_callbacks.thread_detach_func (p->runtime_data);
3923 p->runtime_data = NULL;
3929 sgen_thread_attach (SgenThreadInfo *info)
3932 /*this is odd, can we get attached before the gc is inited?*/
3936 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3937 info->runtime_data = gc_callbacks.thread_attach_func ();
3940 mono_gc_register_thread (void *baseptr)
3942 return mono_thread_info_attach (baseptr) != NULL;
3946 * mono_gc_set_stack_end:
3948 * Set the end of the current threads stack to STACK_END. The stack space between
3949 * STACK_END and the real end of the threads stack will not be scanned during collections.
3952 mono_gc_set_stack_end (void *stack_end)
3954 SgenThreadInfo *info;
3957 info = mono_thread_info_current ();
3959 g_assert (stack_end < info->stack_end);
3960 info->stack_end = stack_end;
3965 #if USE_PTHREAD_INTERCEPT
3969 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3971 return pthread_create (new_thread, attr, start_routine, arg);
3975 mono_gc_pthread_join (pthread_t thread, void **retval)
3977 return pthread_join (thread, retval);
3981 mono_gc_pthread_detach (pthread_t thread)
3983 return pthread_detach (thread);
3987 mono_gc_pthread_exit (void *retval)
3989 mono_thread_info_detach ();
3990 pthread_exit (retval);
3991 g_assert_not_reached ();
3994 #endif /* USE_PTHREAD_INTERCEPT */
3997 * ######################################################################
3998 * ######## Write barriers
3999 * ######################################################################
4003 * Note: the write barriers first do the needed GC work and then do the actual store:
4004 * this way the value is visible to the conservative GC scan after the write barrier
4005 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4006 * the conservative scan, otherwise by the remembered set scan.
4009 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4011 HEAVY_STAT (++stat_wbarrier_set_field);
4012 if (ptr_in_nursery (field_ptr)) {
4013 *(void**)field_ptr = value;
4016 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4018 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4020 remset.wbarrier_set_field (obj, field_ptr, value);
4024 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4026 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4027 if (ptr_in_nursery (slot_ptr)) {
4028 *(void**)slot_ptr = value;
4031 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4033 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4035 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4039 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4041 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4042 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4043 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4044 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4048 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4049 if (binary_protocol_is_heavy_enabled ()) {
4051 for (i = 0; i < count; ++i) {
4052 gpointer dest = (gpointer*)dest_ptr + i;
4053 gpointer obj = *((gpointer*)src_ptr + i);
4055 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4060 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4064 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4068 HEAVY_STAT (++stat_wbarrier_generic_store);
4070 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4071 /* FIXME: ptr_in_heap must be called with the GC lock held */
4072 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4073 char *start = sgen_find_object_for_ptr (ptr);
4074 MonoObject *value = *(MonoObject**)ptr;
4078 MonoObject *obj = (MonoObject*)start;
4079 if (obj->vtable->domain != value->vtable->domain)
4080 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4086 obj = *(gpointer*)ptr;
4088 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4090 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4091 SGEN_LOG (8, "Skipping remset at %p", ptr);
4096 * We need to record old->old pointer locations for the
4097 * concurrent collector.
4099 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4100 SGEN_LOG (8, "Skipping remset at %p", ptr);
4104 SGEN_LOG (8, "Adding remset at %p", ptr);
4106 remset.wbarrier_generic_nostore (ptr);
4110 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4112 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4113 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4114 if (ptr_in_nursery (value))
4115 mono_gc_wbarrier_generic_nostore (ptr);
4116 sgen_dummy_use (value);
4119 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4120 * as an atomic operation with release semantics.
4123 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4125 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4127 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4129 InterlockedWritePointer (ptr, value);
4131 if (ptr_in_nursery (value))
4132 mono_gc_wbarrier_generic_nostore (ptr);
4134 sgen_dummy_use (value);
4137 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4139 mword *dest = _dest;
4144 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4146 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4149 size -= SIZEOF_VOID_P;
4154 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4156 #define HANDLE_PTR(ptr,obj) do { \
4157 gpointer o = *(gpointer*)(ptr); \
4159 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4160 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4165 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4167 #define SCAN_OBJECT_NOVTABLE
4168 #include "sgen-scan-object.h"
4173 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4175 HEAVY_STAT (++stat_wbarrier_value_copy);
4176 g_assert (klass->valuetype);
4178 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4180 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4181 size_t element_size = mono_class_value_size (klass, NULL);
4182 size_t size = count * element_size;
4183 mono_gc_memmove_atomic (dest, src, size);
4187 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4188 if (binary_protocol_is_heavy_enabled ()) {
4189 size_t element_size = mono_class_value_size (klass, NULL);
4191 for (i = 0; i < count; ++i) {
4192 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4193 (char*)src + i * element_size - sizeof (MonoObject),
4194 (mword) klass->gc_descr);
4199 remset.wbarrier_value_copy (dest, src, count, klass);
4203 * mono_gc_wbarrier_object_copy:
4205 * Write barrier to call when obj is the result of a clone or copy of an object.
4208 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4212 HEAVY_STAT (++stat_wbarrier_object_copy);
4214 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4215 size = mono_object_class (obj)->instance_size;
4216 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4217 size - sizeof (MonoObject));
4221 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4222 if (binary_protocol_is_heavy_enabled ())
4223 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4226 remset.wbarrier_object_copy (obj, src);
4231 * ######################################################################
4232 * ######## Other mono public interface functions.
4233 * ######################################################################
4236 #define REFS_SIZE 128
4239 MonoGCReferences callback;
4243 MonoObject *refs [REFS_SIZE];
4244 uintptr_t offsets [REFS_SIZE];
4248 #define HANDLE_PTR(ptr,obj) do { \
4250 if (hwi->count == REFS_SIZE) { \
4251 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4255 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4256 hwi->refs [hwi->count++] = *(ptr); \
4261 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4263 mword desc = sgen_obj_get_descriptor (start);
4265 #include "sgen-scan-object.h"
4269 walk_references (char *start, size_t size, void *data)
4271 HeapWalkInfo *hwi = data;
4274 collect_references (hwi, start, size);
4275 if (hwi->count || !hwi->called)
4276 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4280 * mono_gc_walk_heap:
4281 * @flags: flags for future use
4282 * @callback: a function pointer called for each object in the heap
4283 * @data: a user data pointer that is passed to callback
4285 * This function can be used to iterate over all the live objects in the heap:
4286 * for each object, @callback is invoked, providing info about the object's
4287 * location in memory, its class, its size and the objects it references.
4288 * For each referenced object it's offset from the object address is
4289 * reported in the offsets array.
4290 * The object references may be buffered, so the callback may be invoked
4291 * multiple times for the same object: in all but the first call, the size
4292 * argument will be zero.
4293 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4294 * profiler event handler.
4296 * Returns: a non-zero value if the GC doesn't support heap walking
4299 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4304 hwi.callback = callback;
4307 sgen_clear_nursery_fragments ();
4308 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4310 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4311 sgen_los_iterate_objects (walk_references, &hwi);
4317 mono_gc_collect (int generation)
4322 sgen_perform_collection (0, generation, "user request", TRUE);
4327 mono_gc_max_generation (void)
4333 mono_gc_collection_count (int generation)
4335 if (generation == 0)
4336 return gc_stats.minor_gc_count;
4337 return gc_stats.major_gc_count;
4341 mono_gc_get_used_size (void)
4345 tot = los_memory_usage;
4346 tot += nursery_section->next_data - nursery_section->data;
4347 tot += major_collector.get_used_size ();
4348 /* FIXME: account for pinned objects */
4354 mono_gc_get_los_limit (void)
4356 return MAX_SMALL_OBJ_SIZE;
4360 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4362 mono_unichar2 *new_end = str->chars + new_length;
4364 /* zero the discarded string. This null-delimits the string and allows
4365 * the space to be reclaimed by SGen. */
4367 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4368 CHECK_CANARY_FOR_OBJECT (str);
4369 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4370 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4372 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4375 str->length = new_length;
4379 mono_gc_user_markers_supported (void)
4385 mono_object_is_alive (MonoObject* o)
4391 mono_gc_get_generation (MonoObject *obj)
4393 if (ptr_in_nursery (obj))
4399 mono_gc_enable_events (void)
4404 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4406 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4410 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4412 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4416 mono_gc_weak_link_get (void **link_addr)
4418 void * volatile *link_addr_volatile;
4422 link_addr_volatile = link_addr;
4423 ptr = (void*)*link_addr_volatile;
4425 * At this point we have a hidden pointer. If the GC runs
4426 * here, it will not recognize the hidden pointer as a
4427 * reference, and if the object behind it is not referenced
4428 * elsewhere, it will be freed. Once the world is restarted
4429 * we reveal the pointer, giving us a pointer to a freed
4430 * object. To make sure we don't return it, we load the
4431 * hidden pointer again. If it's still the same, we can be
4432 * sure the object reference is valid.
4435 obj = (MonoObject*) REVEAL_POINTER (ptr);
4439 mono_memory_barrier ();
4442 * During the second bridge processing step the world is
4443 * running again. That step processes all weak links once
4444 * more to null those that refer to dead objects. Before that
4445 * is completed, those links must not be followed, so we
4446 * conservatively wait for bridge processing when any weak
4447 * link is dereferenced.
4449 if (G_UNLIKELY (bridge_processing_in_progress))
4450 mono_gc_wait_for_bridge_processing ();
4452 if ((void*)*link_addr_volatile != ptr)
4459 mono_gc_ephemeron_array_add (MonoObject *obj)
4461 EphemeronLinkNode *node;
4465 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4470 node->array = (char*)obj;
4471 node->next = ephemeron_list;
4472 ephemeron_list = node;
4474 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4481 mono_gc_set_allow_synchronous_major (gboolean flag)
4483 if (!major_collector.is_concurrent)
4486 allow_synchronous_major = flag;
4491 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4495 result = func (data);
4496 UNLOCK_INTERRUPTION;
4501 mono_gc_is_gc_thread (void)
4505 result = mono_thread_info_current () != NULL;
4511 is_critical_method (MonoMethod *method)
4513 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4517 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4521 va_start (ap, description_format);
4523 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4524 vfprintf (stderr, description_format, ap);
4526 fprintf (stderr, " - %s", fallback);
4527 fprintf (stderr, "\n");
4533 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4536 double val = strtod (opt, &endptr);
4537 if (endptr == opt) {
4538 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4541 else if (val < min || val > max) {
4542 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4550 thread_in_critical_region (SgenThreadInfo *info)
4552 return info->in_critical_region;
4556 mono_gc_base_init (void)
4558 MonoThreadInfoCallbacks cb;
4561 char *major_collector_opt = NULL;
4562 char *minor_collector_opt = NULL;
4563 size_t max_heap = 0;
4564 size_t soft_limit = 0;
4567 gboolean debug_print_allowance = FALSE;
4568 double allowance_ratio = 0, save_target = 0;
4569 gboolean cement_enabled = TRUE;
4571 mono_counters_init ();
4574 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4577 /* already inited */
4580 /* being inited by another thread */
4584 /* we will init it */
4587 g_assert_not_reached ();
4589 } while (result != 0);
4591 SGEN_TV_GETTIME (sgen_init_timestamp);
4593 LOCK_INIT (gc_mutex);
4595 pagesize = mono_pagesize ();
4596 gc_debug_file = stderr;
4598 cb.thread_register = sgen_thread_register;
4599 cb.thread_detach = sgen_thread_detach;
4600 cb.thread_unregister = sgen_thread_unregister;
4601 cb.thread_attach = sgen_thread_attach;
4602 cb.mono_method_is_critical = (gpointer)is_critical_method;
4603 cb.mono_thread_in_critical_region = thread_in_critical_region;
4605 cb.thread_exit = mono_gc_pthread_exit;
4606 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4609 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4611 LOCK_INIT (sgen_interruption_mutex);
4613 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4614 opts = g_strsplit (env, ",", -1);
4615 for (ptr = opts; *ptr; ++ptr) {
4617 if (g_str_has_prefix (opt, "major=")) {
4618 opt = strchr (opt, '=') + 1;
4619 major_collector_opt = g_strdup (opt);
4620 } else if (g_str_has_prefix (opt, "minor=")) {
4621 opt = strchr (opt, '=') + 1;
4622 minor_collector_opt = g_strdup (opt);
4630 sgen_init_internal_allocator ();
4631 sgen_init_nursery_allocator ();
4632 sgen_init_fin_weak_hash ();
4634 sgen_init_hash_table ();
4635 sgen_init_descriptors ();
4636 sgen_init_gray_queues ();
4638 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4639 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4640 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4641 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4643 #ifndef HAVE_KW_THREAD
4644 mono_native_tls_alloc (&thread_info_key, NULL);
4645 #if defined(__APPLE__) || defined (HOST_WIN32)
4647 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4648 * where the two are the same.
4650 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4654 int tls_offset = -1;
4655 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4656 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4661 * This needs to happen before any internal allocations because
4662 * it inits the small id which is required for hazard pointer
4667 mono_thread_info_attach (&dummy);
4669 if (!minor_collector_opt) {
4670 sgen_simple_nursery_init (&sgen_minor_collector);
4672 if (!strcmp (minor_collector_opt, "simple")) {
4674 sgen_simple_nursery_init (&sgen_minor_collector);
4675 } else if (!strcmp (minor_collector_opt, "split")) {
4676 sgen_split_nursery_init (&sgen_minor_collector);
4678 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4679 goto use_simple_nursery;
4683 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4684 use_marksweep_major:
4685 sgen_marksweep_init (&major_collector);
4686 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4687 sgen_marksweep_conc_init (&major_collector);
4689 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4690 goto use_marksweep_major;
4693 ///* Keep this the default for now */
4694 /* Precise marking is broken on all supported targets. Disable until fixed. */
4695 conservative_stack_mark = TRUE;
4697 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4699 if (major_collector.is_concurrent)
4700 cement_enabled = FALSE;
4703 gboolean usage_printed = FALSE;
4705 for (ptr = opts; *ptr; ++ptr) {
4707 if (!strcmp (opt, ""))
4709 if (g_str_has_prefix (opt, "major="))
4711 if (g_str_has_prefix (opt, "minor="))
4713 if (g_str_has_prefix (opt, "max-heap-size=")) {
4714 size_t max_heap_candidate = 0;
4715 opt = strchr (opt, '=') + 1;
4716 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4717 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4718 if (max_heap != max_heap_candidate)
4719 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4721 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4725 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4726 opt = strchr (opt, '=') + 1;
4727 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4728 if (soft_limit <= 0) {
4729 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4733 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4737 if (g_str_has_prefix (opt, "stack-mark=")) {
4738 opt = strchr (opt, '=') + 1;
4739 if (!strcmp (opt, "precise")) {
4740 conservative_stack_mark = FALSE;
4741 } else if (!strcmp (opt, "conservative")) {
4742 conservative_stack_mark = TRUE;
4744 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4745 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4749 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4750 opt = strchr (opt, '=') + 1;
4751 sgen_set_bridge_implementation (opt);
4754 if (g_str_has_prefix (opt, "toggleref-test")) {
4755 sgen_register_test_toggleref_callback ();
4760 if (g_str_has_prefix (opt, "nursery-size=")) {
4762 opt = strchr (opt, '=') + 1;
4763 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4764 #ifdef SGEN_ALIGN_NURSERY
4765 if ((val & (val - 1))) {
4766 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4770 if (val < SGEN_MAX_NURSERY_WASTE) {
4771 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4772 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4776 sgen_nursery_size = val;
4777 sgen_nursery_bits = 0;
4778 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4781 sgen_nursery_size = val;
4784 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4790 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4792 opt = strchr (opt, '=') + 1;
4793 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4794 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4799 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4801 opt = strchr (opt, '=') + 1;
4802 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4803 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4804 allowance_ratio = val;
4808 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4809 if (!major_collector.is_concurrent) {
4810 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4814 opt = strchr (opt, '=') + 1;
4816 if (!strcmp (opt, "yes")) {
4817 allow_synchronous_major = TRUE;
4818 } else if (!strcmp (opt, "no")) {
4819 allow_synchronous_major = FALSE;
4821 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4826 if (!strcmp (opt, "cementing")) {
4827 cement_enabled = TRUE;
4830 if (!strcmp (opt, "no-cementing")) {
4831 cement_enabled = FALSE;
4835 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4838 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4841 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4846 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4847 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4848 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4849 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4850 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4851 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4852 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4853 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4854 fprintf (stderr, " [no-]cementing\n");
4855 if (major_collector.is_concurrent)
4856 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4857 if (major_collector.print_gc_param_usage)
4858 major_collector.print_gc_param_usage ();
4859 if (sgen_minor_collector.print_gc_param_usage)
4860 sgen_minor_collector.print_gc_param_usage ();
4861 fprintf (stderr, " Experimental options:\n");
4862 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4863 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);
4864 fprintf (stderr, "\n");
4866 usage_printed = TRUE;
4871 if (major_collector.is_concurrent)
4872 sgen_workers_init (1);
4874 if (major_collector_opt)
4875 g_free (major_collector_opt);
4877 if (minor_collector_opt)
4878 g_free (minor_collector_opt);
4882 if (major_collector.is_concurrent && cement_enabled) {
4883 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported on concurrent major collectors.");
4884 cement_enabled = FALSE;
4887 sgen_cement_init (cement_enabled);
4889 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4890 gboolean usage_printed = FALSE;
4892 opts = g_strsplit (env, ",", -1);
4893 for (ptr = opts; ptr && *ptr; ptr ++) {
4895 if (!strcmp (opt, ""))
4897 if (opt [0] >= '0' && opt [0] <= '9') {
4898 gc_debug_level = atoi (opt);
4903 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4904 gc_debug_file = fopen (rf, "wb");
4906 gc_debug_file = stderr;
4909 } else if (!strcmp (opt, "print-allowance")) {
4910 debug_print_allowance = TRUE;
4911 } else if (!strcmp (opt, "print-pinning")) {
4912 do_pin_stats = TRUE;
4913 } else if (!strcmp (opt, "verify-before-allocs")) {
4914 verify_before_allocs = 1;
4915 has_per_allocation_action = TRUE;
4916 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4917 char *arg = strchr (opt, '=') + 1;
4918 verify_before_allocs = atoi (arg);
4919 has_per_allocation_action = TRUE;
4920 } else if (!strcmp (opt, "collect-before-allocs")) {
4921 collect_before_allocs = 1;
4922 has_per_allocation_action = TRUE;
4923 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4924 char *arg = strchr (opt, '=') + 1;
4925 has_per_allocation_action = TRUE;
4926 collect_before_allocs = atoi (arg);
4927 } else if (!strcmp (opt, "verify-before-collections")) {
4928 whole_heap_check_before_collection = TRUE;
4929 } else if (!strcmp (opt, "check-at-minor-collections")) {
4930 consistency_check_at_minor_collection = TRUE;
4931 nursery_clear_policy = CLEAR_AT_GC;
4932 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4933 if (!major_collector.is_concurrent) {
4934 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4937 mod_union_consistency_check = TRUE;
4938 } else if (!strcmp (opt, "check-mark-bits")) {
4939 check_mark_bits_after_major_collection = TRUE;
4940 } else if (!strcmp (opt, "check-nursery-pinned")) {
4941 check_nursery_objects_pinned = TRUE;
4942 } else if (!strcmp (opt, "xdomain-checks")) {
4943 xdomain_checks = TRUE;
4944 } else if (!strcmp (opt, "clear-at-gc")) {
4945 nursery_clear_policy = CLEAR_AT_GC;
4946 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4947 nursery_clear_policy = CLEAR_AT_GC;
4948 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4949 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4950 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4951 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4952 } else if (!strcmp (opt, "check-scan-starts")) {
4953 do_scan_starts_check = TRUE;
4954 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4955 do_verify_nursery = TRUE;
4956 } else if (!strcmp (opt, "check-concurrent")) {
4957 if (!major_collector.is_concurrent) {
4958 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4961 do_concurrent_checks = TRUE;
4962 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4963 do_dump_nursery_content = TRUE;
4964 } else if (!strcmp (opt, "no-managed-allocator")) {
4965 sgen_set_use_managed_allocator (FALSE);
4966 } else if (!strcmp (opt, "disable-minor")) {
4967 disable_minor_collections = TRUE;
4968 } else if (!strcmp (opt, "disable-major")) {
4969 disable_major_collections = TRUE;
4970 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4971 char *filename = strchr (opt, '=') + 1;
4972 nursery_clear_policy = CLEAR_AT_GC;
4973 heap_dump_file = fopen (filename, "w");
4974 if (heap_dump_file) {
4975 fprintf (heap_dump_file, "<sgen-dump>\n");
4976 do_pin_stats = TRUE;
4978 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4979 char *filename = strchr (opt, '=') + 1;
4980 char *colon = strrchr (filename, ':');
4983 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
4984 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
4989 binary_protocol_init (filename, (long long)limit);
4990 } else if (!strcmp (opt, "nursery-canaries")) {
4991 do_verify_nursery = TRUE;
4992 sgen_set_use_managed_allocator (FALSE);
4993 enable_nursery_canaries = TRUE;
4994 } else if (!strcmp (opt, "do-not-finalize")) {
4995 do_not_finalize = TRUE;
4996 } else if (!strcmp (opt, "log-finalizers")) {
4997 log_finalizers = TRUE;
4998 } else if (!sgen_bridge_handle_gc_debug (opt)) {
4999 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5004 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);
5005 fprintf (stderr, "Valid <option>s are:\n");
5006 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5007 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5008 fprintf (stderr, " check-at-minor-collections\n");
5009 fprintf (stderr, " check-mark-bits\n");
5010 fprintf (stderr, " check-nursery-pinned\n");
5011 fprintf (stderr, " verify-before-collections\n");
5012 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5013 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5014 fprintf (stderr, " disable-minor\n");
5015 fprintf (stderr, " disable-major\n");
5016 fprintf (stderr, " xdomain-checks\n");
5017 fprintf (stderr, " check-concurrent\n");
5018 fprintf (stderr, " clear-[nursery-]at-gc\n");
5019 fprintf (stderr, " clear-at-tlab-creation\n");
5020 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5021 fprintf (stderr, " check-scan-starts\n");
5022 fprintf (stderr, " no-managed-allocator\n");
5023 fprintf (stderr, " print-allowance\n");
5024 fprintf (stderr, " print-pinning\n");
5025 fprintf (stderr, " heap-dump=<filename>\n");
5026 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5027 fprintf (stderr, " nursery-canaries\n");
5028 fprintf (stderr, " do-not-finalize\n");
5029 fprintf (stderr, " log-finalizers\n");
5030 sgen_bridge_print_gc_debug_usage ();
5031 fprintf (stderr, "\n");
5033 usage_printed = TRUE;
5039 if (check_mark_bits_after_major_collection)
5040 nursery_clear_policy = CLEAR_AT_GC;
5042 if (major_collector.post_param_init)
5043 major_collector.post_param_init (&major_collector);
5045 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5047 memset (&remset, 0, sizeof (remset));
5049 sgen_card_table_init (&remset);
5055 mono_gc_get_gc_name (void)
5060 static MonoMethod *write_barrier_method;
5063 sgen_is_critical_method (MonoMethod *method)
5065 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5069 sgen_has_critical_method (void)
5071 return write_barrier_method || sgen_has_managed_allocator ();
5077 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5079 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5080 #ifdef SGEN_ALIGN_NURSERY
5081 // if (ptr_in_nursery (ptr)) return;
5083 * Masking out the bits might be faster, but we would have to use 64 bit
5084 * immediates, which might be slower.
5086 mono_mb_emit_ldarg (mb, 0);
5087 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5088 mono_mb_emit_byte (mb, CEE_SHR_UN);
5089 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5090 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5092 if (!major_collector.is_concurrent) {
5093 // if (!ptr_in_nursery (*ptr)) return;
5094 mono_mb_emit_ldarg (mb, 0);
5095 mono_mb_emit_byte (mb, CEE_LDIND_I);
5096 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5097 mono_mb_emit_byte (mb, CEE_SHR_UN);
5098 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5099 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5102 int label_continue1, label_continue2;
5103 int dereferenced_var;
5105 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5106 mono_mb_emit_ldarg (mb, 0);
5107 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5108 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5110 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5111 mono_mb_emit_ldarg (mb, 0);
5112 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5113 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5116 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5119 mono_mb_patch_branch (mb, label_continue_1);
5120 mono_mb_patch_branch (mb, label_continue_2);
5122 // Dereference and store in local var
5123 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5124 mono_mb_emit_ldarg (mb, 0);
5125 mono_mb_emit_byte (mb, CEE_LDIND_I);
5126 mono_mb_emit_stloc (mb, dereferenced_var);
5128 if (!major_collector.is_concurrent) {
5129 // if (*ptr < sgen_get_nursery_start ()) return;
5130 mono_mb_emit_ldloc (mb, dereferenced_var);
5131 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5132 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5134 // if (*ptr >= sgen_get_nursery_end ()) return;
5135 mono_mb_emit_ldloc (mb, dereferenced_var);
5136 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5137 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5144 mono_gc_get_write_barrier (void)
5147 MonoMethodBuilder *mb;
5148 MonoMethodSignature *sig;
5149 #ifdef MANAGED_WBARRIER
5150 int i, nursery_check_labels [3];
5152 #ifdef HAVE_KW_THREAD
5153 int stack_end_offset = -1;
5155 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5156 g_assert (stack_end_offset != -1);
5160 // FIXME: Maybe create a separate version for ctors (the branch would be
5161 // correctly predicted more times)
5162 if (write_barrier_method)
5163 return write_barrier_method;
5165 /* Create the IL version of mono_gc_barrier_generic_store () */
5166 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5167 sig->ret = &mono_defaults.void_class->byval_arg;
5168 sig->params [0] = &mono_defaults.int_class->byval_arg;
5170 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5173 #ifdef MANAGED_WBARRIER
5174 emit_nursery_check (mb, nursery_check_labels);
5176 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5180 LDC_PTR sgen_cardtable
5182 address >> CARD_BITS
5186 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5187 LDC_PTR card_table_mask
5194 mono_mb_emit_ptr (mb, sgen_cardtable);
5195 mono_mb_emit_ldarg (mb, 0);
5196 mono_mb_emit_icon (mb, CARD_BITS);
5197 mono_mb_emit_byte (mb, CEE_SHR_UN);
5198 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5199 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5200 mono_mb_emit_byte (mb, CEE_AND);
5202 mono_mb_emit_byte (mb, CEE_ADD);
5203 mono_mb_emit_icon (mb, 1);
5204 mono_mb_emit_byte (mb, CEE_STIND_I1);
5207 for (i = 0; i < 3; ++i) {
5208 if (nursery_check_labels [i])
5209 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5211 mono_mb_emit_byte (mb, CEE_RET);
5213 mono_mb_emit_ldarg (mb, 0);
5214 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5215 mono_mb_emit_byte (mb, CEE_RET);
5218 res = mono_mb_create_method (mb, sig, 16);
5222 if (write_barrier_method) {
5223 /* Already created */
5224 mono_free_method (res);
5226 /* double-checked locking */
5227 mono_memory_barrier ();
5228 write_barrier_method = res;
5232 return write_barrier_method;
5236 mono_gc_get_description (void)
5238 return g_strdup ("sgen");
5242 mono_gc_set_desktop_mode (void)
5247 mono_gc_is_moving (void)
5253 mono_gc_is_disabled (void)
5259 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5266 sgen_get_nursery_clear_policy (void)
5268 return nursery_clear_policy;
5272 sgen_get_array_fill_vtable (void)
5274 if (!array_fill_vtable) {
5275 static MonoClass klass;
5276 static char _vtable[sizeof(MonoVTable)+8];
5277 MonoVTable* vtable = (MonoVTable*) ALIGN_TO(_vtable, 8);
5280 MonoDomain *domain = mono_get_root_domain ();
5283 klass.element_class = mono_defaults.byte_class;
5285 klass.instance_size = sizeof (MonoArray);
5286 klass.sizes.element_size = 1;
5287 klass.name = "array_filler_type";
5289 vtable->klass = &klass;
5291 vtable->gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5294 array_fill_vtable = vtable;
5296 return array_fill_vtable;
5306 sgen_gc_unlock (void)
5308 gboolean try_free = sgen_try_free_some_memory;
5309 sgen_try_free_some_memory = FALSE;
5310 mono_mutex_unlock (&gc_mutex);
5311 MONO_GC_UNLOCKED ();
5313 mono_thread_hazardous_try_free_some ();
5317 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5319 major_collector.iterate_live_block_ranges (callback);
5323 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5325 major_collector.scan_card_table (FALSE, queue);
5329 sgen_get_major_collector (void)
5331 return &major_collector;
5334 void mono_gc_set_skip_thread (gboolean skip)
5336 SgenThreadInfo *info = mono_thread_info_current ();
5339 info->gc_disabled = skip;
5344 sgen_get_remset (void)
5350 mono_gc_get_vtable_bits (MonoClass *class)
5353 /* FIXME move this to the bridge code */
5354 if (sgen_need_bridge_processing ()) {
5355 switch (sgen_bridge_class_kind (class)) {
5356 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5357 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5358 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5360 case GC_BRIDGE_OPAQUE_CLASS:
5361 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5363 case GC_BRIDGE_TRANSPARENT_CLASS:
5367 if (fin_callbacks.is_class_finalization_aware) {
5368 if (fin_callbacks.is_class_finalization_aware (class))
5369 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5375 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5382 sgen_check_whole_heap_stw (void)
5384 sgen_stop_world (0);
5385 sgen_clear_nursery_fragments ();
5386 sgen_check_whole_heap (FALSE);
5387 sgen_restart_world (0, NULL);
5391 sgen_gc_event_moves (void)
5393 if (moved_objects_idx) {
5394 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5395 moved_objects_idx = 0;
5400 sgen_timestamp (void)
5402 SGEN_TV_DECLARE (timestamp);
5403 SGEN_TV_GETTIME (timestamp);
5404 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5408 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5410 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5411 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5413 fin_callbacks = *callbacks;
5420 #endif /* HAVE_SGEN_GC */