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 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1389 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1390 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 ());
1391 section->data = section->next_data = data;
1392 section->size = alloc_size;
1393 section->end_data = data + sgen_nursery_size;
1394 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1395 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1396 section->num_scan_start = scan_starts;
1398 nursery_section = section;
1400 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1404 mono_gc_get_nursery (int *shift_bits, size_t *size)
1406 *size = sgen_nursery_size;
1407 *shift_bits = DEFAULT_NURSERY_BITS;
1408 return sgen_get_nursery_start ();
1412 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1414 SgenThreadInfo *info = mono_thread_info_current ();
1416 /* Could be called from sgen_thread_unregister () with a NULL info */
1419 info->stopped_domain = domain;
1424 mono_gc_precise_stack_mark_enabled (void)
1426 return !conservative_stack_mark;
1430 mono_gc_get_logfile (void)
1432 return gc_debug_file;
1436 report_finalizer_roots_list (FinalizeReadyEntry *list)
1438 GCRootReport report;
1439 FinalizeReadyEntry *fin;
1442 for (fin = list; fin; fin = fin->next) {
1445 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1447 notify_gc_roots (&report);
1451 report_finalizer_roots (void)
1453 report_finalizer_roots_list (fin_ready_list);
1454 report_finalizer_roots_list (critical_fin_list);
1457 static GCRootReport *root_report;
1460 single_arg_report_root (void **obj, void *gc_data)
1463 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1467 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1469 switch (desc & ROOT_DESC_TYPE_MASK) {
1470 case ROOT_DESC_BITMAP:
1471 desc >>= ROOT_DESC_TYPE_SHIFT;
1473 if ((desc & 1) && *start_root) {
1474 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1480 case ROOT_DESC_COMPLEX: {
1481 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1482 gsize bwords = (*bitmap_data) - 1;
1483 void **start_run = start_root;
1485 while (bwords-- > 0) {
1486 gsize bmap = *bitmap_data++;
1487 void **objptr = start_run;
1489 if ((bmap & 1) && *objptr) {
1490 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1495 start_run += GC_BITS_PER_WORD;
1499 case ROOT_DESC_USER: {
1500 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1501 root_report = report;
1502 marker (start_root, single_arg_report_root, NULL);
1505 case ROOT_DESC_RUN_LEN:
1506 g_assert_not_reached ();
1508 g_assert_not_reached ();
1513 report_registered_roots_by_type (int root_type)
1515 GCRootReport report;
1519 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1520 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1521 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1522 } SGEN_HASH_TABLE_FOREACH_END;
1523 notify_gc_roots (&report);
1527 report_registered_roots (void)
1529 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1530 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1534 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1536 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1537 SgenGrayQueue *queue = ctx.queue;
1538 FinalizeReadyEntry *fin;
1540 for (fin = list; fin; fin = fin->next) {
1543 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1544 copy_func (&fin->object, queue);
1549 generation_name (int generation)
1551 switch (generation) {
1552 case GENERATION_NURSERY: return "nursery";
1553 case GENERATION_OLD: return "old";
1554 default: g_assert_not_reached ();
1559 sgen_generation_name (int generation)
1561 return generation_name (generation);
1564 SgenObjectOperations *
1565 sgen_get_current_object_ops (void){
1566 return ¤t_object_ops;
1571 finish_gray_stack (int generation, GrayQueue *queue)
1575 int done_with_ephemerons, ephemeron_rounds = 0;
1576 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1577 ScanObjectFunc scan_func = current_object_ops.scan_object;
1578 ScanCopyContext ctx = { scan_func, copy_func, queue };
1579 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1580 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1583 * We copied all the reachable objects. Now it's the time to copy
1584 * the objects that were not referenced by the roots, but by the copied objects.
1585 * we built a stack of objects pointed to by gray_start: they are
1586 * additional roots and we may add more items as we go.
1587 * We loop until gray_start == gray_objects which means no more objects have
1588 * been added. Note this is iterative: no recursion is involved.
1589 * We need to walk the LO list as well in search of marked big objects
1590 * (use a flag since this is needed only on major collections). We need to loop
1591 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1592 * To achieve better cache locality and cache usage, we drain the gray stack
1593 * frequently, after each object is copied, and just finish the work here.
1595 sgen_drain_gray_stack (-1, ctx);
1597 SGEN_LOG (2, "%s generation done", generation_name (generation));
1600 Reset bridge data, we might have lingering data from a previous collection if this is a major
1601 collection trigged by minor overflow.
1603 We must reset the gathered bridges since their original block might be evacuated due to major
1604 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1606 if (sgen_need_bridge_processing ())
1607 sgen_bridge_reset_data ();
1610 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1611 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1612 * objects that are in fact reachable.
1614 done_with_ephemerons = 0;
1616 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1617 sgen_drain_gray_stack (-1, ctx);
1619 } while (!done_with_ephemerons);
1621 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1623 if (sgen_need_bridge_processing ()) {
1624 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1625 sgen_drain_gray_stack (-1, ctx);
1626 sgen_collect_bridge_objects (generation, ctx);
1627 if (generation == GENERATION_OLD)
1628 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1631 Do the first bridge step here, as the collector liveness state will become useless after that.
1633 An important optimization is to only proccess the possibly dead part of the object graph and skip
1634 over all live objects as we transitively know everything they point must be alive too.
1636 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1638 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1639 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1642 sgen_bridge_processing_stw_step ();
1646 Make sure we drain the gray stack before processing disappearing links and finalizers.
1647 If we don't make sure it is empty we might wrongly see a live object as dead.
1649 sgen_drain_gray_stack (-1, ctx);
1652 We must clear weak links that don't track resurrection before processing object ready for
1653 finalization so they can be cleared before that.
1655 sgen_null_link_in_range (generation, TRUE, ctx);
1656 if (generation == GENERATION_OLD)
1657 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1660 /* walk the finalization queue and move also the objects that need to be
1661 * finalized: use the finalized objects as new roots so the objects they depend
1662 * on are also not reclaimed. As with the roots above, only objects in the nursery
1663 * are marked/copied.
1665 sgen_finalize_in_range (generation, ctx);
1666 if (generation == GENERATION_OLD)
1667 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1668 /* drain the new stack that might have been created */
1669 SGEN_LOG (6, "Precise scan of gray area post fin");
1670 sgen_drain_gray_stack (-1, ctx);
1673 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1675 done_with_ephemerons = 0;
1677 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1678 sgen_drain_gray_stack (-1, ctx);
1680 } while (!done_with_ephemerons);
1683 * Clear ephemeron pairs with unreachable keys.
1684 * We pass the copy func so we can figure out if an array was promoted or not.
1686 clear_unreachable_ephemerons (ctx);
1689 * We clear togglerefs only after all possible chances of revival are done.
1690 * This is semantically more inline with what users expect and it allows for
1691 * user finalizers to correctly interact with TR objects.
1693 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1696 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1699 * handle disappearing links
1700 * Note we do this after checking the finalization queue because if an object
1701 * survives (at least long enough to be finalized) we don't clear the link.
1702 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1703 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1706 g_assert (sgen_gray_object_queue_is_empty (queue));
1708 sgen_null_link_in_range (generation, FALSE, ctx);
1709 if (generation == GENERATION_OLD)
1710 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1711 if (sgen_gray_object_queue_is_empty (queue))
1713 sgen_drain_gray_stack (-1, ctx);
1716 g_assert (sgen_gray_object_queue_is_empty (queue));
1718 sgen_gray_object_queue_trim_free_list (queue);
1722 sgen_check_section_scan_starts (GCMemSection *section)
1725 for (i = 0; i < section->num_scan_start; ++i) {
1726 if (section->scan_starts [i]) {
1727 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1728 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1734 check_scan_starts (void)
1736 if (!do_scan_starts_check)
1738 sgen_check_section_scan_starts (nursery_section);
1739 major_collector.check_scan_starts ();
1743 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1747 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1748 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1749 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1750 } SGEN_HASH_TABLE_FOREACH_END;
1754 sgen_dump_occupied (char *start, char *end, char *section_start)
1756 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1760 sgen_dump_section (GCMemSection *section, const char *type)
1762 char *start = section->data;
1763 char *end = section->data + section->size;
1764 char *occ_start = NULL;
1766 char *old_start G_GNUC_UNUSED = NULL; /* just for debugging */
1768 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1770 while (start < end) {
1772 MonoClass *class G_GNUC_UNUSED;
1774 if (!*(void**)start) {
1776 sgen_dump_occupied (occ_start, start, section->data);
1779 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1782 g_assert (start < section->next_data);
1787 vt = (GCVTable*)LOAD_VTABLE (start);
1790 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1793 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1794 start - section->data,
1795 vt->klass->name_space, vt->klass->name,
1803 sgen_dump_occupied (occ_start, start, section->data);
1805 fprintf (heap_dump_file, "</section>\n");
1809 dump_object (MonoObject *obj, gboolean dump_location)
1811 static char class_name [1024];
1813 MonoClass *class = mono_object_class (obj);
1817 * Python's XML parser is too stupid to parse angle brackets
1818 * in strings, so we just ignore them;
1821 while (class->name [i] && j < sizeof (class_name) - 1) {
1822 if (!strchr ("<>\"", class->name [i]))
1823 class_name [j++] = class->name [i];
1826 g_assert (j < sizeof (class_name));
1829 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1830 class->name_space, class_name,
1831 safe_object_get_size (obj));
1832 if (dump_location) {
1833 const char *location;
1834 if (ptr_in_nursery (obj))
1835 location = "nursery";
1836 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1840 fprintf (heap_dump_file, " location=\"%s\"", location);
1842 fprintf (heap_dump_file, "/>\n");
1846 dump_heap (const char *type, int num, const char *reason)
1851 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1853 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1854 fprintf (heap_dump_file, ">\n");
1855 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1856 sgen_dump_internal_mem_usage (heap_dump_file);
1857 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1858 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1859 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1861 fprintf (heap_dump_file, "<pinned-objects>\n");
1862 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1863 dump_object (list->obj, TRUE);
1864 fprintf (heap_dump_file, "</pinned-objects>\n");
1866 sgen_dump_section (nursery_section, "nursery");
1868 major_collector.dump_heap (heap_dump_file);
1870 fprintf (heap_dump_file, "<los>\n");
1871 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1872 dump_object ((MonoObject*)bigobj->data, FALSE);
1873 fprintf (heap_dump_file, "</los>\n");
1875 fprintf (heap_dump_file, "</collection>\n");
1879 sgen_register_moved_object (void *obj, void *destination)
1881 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1883 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1884 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1885 moved_objects_idx = 0;
1887 moved_objects [moved_objects_idx++] = obj;
1888 moved_objects [moved_objects_idx++] = destination;
1894 static gboolean inited = FALSE;
1899 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1901 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1902 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1903 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1904 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1905 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1906 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1907 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1908 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1910 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1911 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1912 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1913 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1914 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1915 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1916 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1917 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1918 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1919 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1920 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1921 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1922 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1924 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1926 #ifdef HEAVY_STATISTICS
1927 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1928 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1929 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1930 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1931 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1932 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1933 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1934 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1935 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1937 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1938 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1940 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1941 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1942 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1943 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1945 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1946 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1948 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1950 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1951 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1952 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1953 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1955 sgen_nursery_allocator_init_heavy_stats ();
1956 sgen_alloc_init_heavy_stats ();
1964 reset_pinned_from_failed_allocation (void)
1966 bytes_pinned_from_failed_allocation = 0;
1970 sgen_set_pinned_from_failed_allocation (mword objsize)
1972 bytes_pinned_from_failed_allocation += objsize;
1976 sgen_collection_is_concurrent (void)
1978 switch (current_collection_generation) {
1979 case GENERATION_NURSERY:
1981 case GENERATION_OLD:
1982 return concurrent_collection_in_progress;
1984 g_error ("Invalid current generation %d", current_collection_generation);
1989 sgen_concurrent_collection_in_progress (void)
1991 return concurrent_collection_in_progress;
1995 job_remembered_set_scan (WorkerData *worker_data, void *dummy)
1997 remset.scan_remsets (sgen_workers_get_job_gray_queue (worker_data));
2002 CopyOrMarkObjectFunc copy_or_mark_func;
2003 ScanObjectFunc scan_func;
2007 } ScanFromRegisteredRootsJobData;
2010 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2012 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2013 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2014 sgen_workers_get_job_gray_queue (worker_data) };
2016 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2017 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2024 } ScanThreadDataJobData;
2027 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2029 ScanThreadDataJobData *job_data = job_data_untyped;
2031 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2032 sgen_workers_get_job_gray_queue (worker_data));
2033 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2037 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2039 FinalizeReadyEntry *list = job_data_untyped;
2040 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2042 scan_finalizer_entries (list, ctx);
2046 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2048 g_assert (concurrent_collection_in_progress);
2049 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2053 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2055 g_assert (concurrent_collection_in_progress);
2056 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2060 verify_scan_starts (char *start, char *end)
2064 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2065 char *addr = nursery_section->scan_starts [i];
2066 if (addr > start && addr < end)
2067 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2072 verify_nursery (void)
2074 char *start, *end, *cur, *hole_start;
2076 if (!do_verify_nursery)
2079 if (nursery_canaries_enabled ())
2080 SGEN_LOG (1, "Checking nursery canaries...");
2082 /*This cleans up unused fragments */
2083 sgen_nursery_allocator_prepare_for_pinning ();
2085 hole_start = start = cur = sgen_get_nursery_start ();
2086 end = sgen_get_nursery_end ();
2091 if (!*(void**)cur) {
2092 cur += sizeof (void*);
2096 if (object_is_forwarded (cur))
2097 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2098 else if (object_is_pinned (cur))
2099 SGEN_LOG (1, "PINNED OBJ %p", cur);
2101 ss = safe_object_get_size ((MonoObject*)cur);
2102 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2103 verify_scan_starts (cur, cur + size);
2104 if (do_dump_nursery_content) {
2105 if (cur > hole_start)
2106 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2107 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 ());
2109 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2110 CHECK_CANARY_FOR_OBJECT (cur);
2111 CANARIFY_SIZE (size);
2119 * Checks that no objects in the nursery are fowarded or pinned. This
2120 * is a precondition to restarting the mutator while doing a
2121 * concurrent collection. Note that we don't clear fragments because
2122 * we depend on that having happened earlier.
2125 check_nursery_is_clean (void)
2129 cur = sgen_get_nursery_start ();
2130 end = sgen_get_nursery_end ();
2135 if (!*(void**)cur) {
2136 cur += sizeof (void*);
2140 g_assert (!object_is_forwarded (cur));
2141 g_assert (!object_is_pinned (cur));
2143 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2144 verify_scan_starts (cur, cur + size);
2151 init_gray_queue (void)
2153 if (sgen_collection_is_concurrent ())
2154 sgen_workers_init_distribute_gray_queue ();
2155 sgen_gray_object_queue_init (&gray_queue, NULL);
2159 * Perform a nursery collection.
2161 * Return whether any objects were late-pinned due to being out of memory.
2164 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2166 gboolean needs_major;
2167 size_t max_garbage_amount;
2169 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2170 ScanThreadDataJobData *stdjd;
2171 mword fragment_total;
2172 ScanCopyContext ctx;
2176 if (disable_minor_collections)
2179 TV_GETTIME (last_minor_collection_start_tv);
2180 atv = last_minor_collection_start_tv;
2182 MONO_GC_BEGIN (GENERATION_NURSERY);
2183 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2187 #ifndef DISABLE_PERFCOUNTERS
2188 mono_perfcounters->gc_collections0++;
2191 current_collection_generation = GENERATION_NURSERY;
2192 current_object_ops = sgen_minor_collector.serial_ops;
2194 reset_pinned_from_failed_allocation ();
2196 check_scan_starts ();
2198 sgen_nursery_alloc_prepare_for_minor ();
2202 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2203 /* FIXME: optimize later to use the higher address where an object can be present */
2204 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2206 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 ()));
2207 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2208 g_assert (nursery_section->size >= max_garbage_amount);
2210 /* world must be stopped already */
2212 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2214 if (xdomain_checks) {
2215 sgen_clear_nursery_fragments ();
2216 sgen_check_for_xdomain_refs ();
2219 nursery_section->next_data = nursery_next;
2221 major_collector.start_nursery_collection ();
2223 sgen_memgov_minor_collection_start ();
2227 gc_stats.minor_gc_count ++;
2229 if (whole_heap_check_before_collection) {
2230 sgen_clear_nursery_fragments ();
2231 sgen_check_whole_heap (finish_up_concurrent_mark);
2233 if (consistency_check_at_minor_collection)
2234 sgen_check_consistency ();
2236 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2238 sgen_process_fin_stage_entries ();
2239 sgen_process_dislink_stage_entries ();
2241 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2243 /* pin from pinned handles */
2244 sgen_init_pinning ();
2245 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2246 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2247 /* pin cemented objects */
2248 sgen_pin_cemented_objects ();
2249 /* identify pinned objects */
2250 sgen_optimize_pin_queue ();
2251 sgen_pinning_setup_section (nursery_section);
2252 ctx.scan_func = NULL;
2253 ctx.copy_func = NULL;
2254 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2255 pin_objects_in_nursery (ctx);
2256 sgen_pinning_trim_queue_to_section (nursery_section);
2259 time_minor_pinning += TV_ELAPSED (btv, atv);
2260 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2261 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2263 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2266 * FIXME: When we finish a concurrent collection we do a nursery collection first,
2267 * as part of which we scan the card table. Then, later, we scan the mod union
2268 * cardtable. We should only have to do one.
2270 sgen_workers_enqueue_job ("scan remset", job_remembered_set_scan, NULL);
2272 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2274 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2275 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2277 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2279 /* FIXME: why is this here? */
2280 ctx.scan_func = current_object_ops.scan_object;
2281 ctx.copy_func = NULL;
2282 ctx.queue = &gray_queue;
2283 sgen_drain_gray_stack (-1, ctx);
2285 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2286 report_registered_roots ();
2287 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2288 report_finalizer_roots ();
2290 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2292 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2294 /* registered roots, this includes static fields */
2295 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2296 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2297 scrrjd_normal->scan_func = current_object_ops.scan_object;
2298 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2299 scrrjd_normal->heap_end = nursery_next;
2300 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2301 sgen_workers_enqueue_job ("scan from registered roots normal", job_scan_from_registered_roots, scrrjd_normal);
2303 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2304 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2305 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2306 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2307 scrrjd_wbarrier->heap_end = nursery_next;
2308 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2309 sgen_workers_enqueue_job ("scan from registered roots wbarrier", job_scan_from_registered_roots, scrrjd_wbarrier);
2312 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2314 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2317 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2318 stdjd->heap_start = sgen_get_nursery_start ();
2319 stdjd->heap_end = nursery_next;
2320 sgen_workers_enqueue_job ("scan thread data", job_scan_thread_data, stdjd);
2323 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2326 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2328 g_assert (!sgen_collection_is_concurrent ());
2330 /* Scan the list of objects ready for finalization. If */
2331 sgen_workers_enqueue_job ("scan finalizer entries", job_scan_finalizer_entries, fin_ready_list);
2332 sgen_workers_enqueue_job ("scan criticial finalizer entries", job_scan_finalizer_entries, critical_fin_list);
2334 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2336 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2338 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2339 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2341 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2344 * The (single-threaded) finalization code might have done
2345 * some copying/marking so we can only reset the GC thread's
2346 * worker data here instead of earlier when we joined the
2349 sgen_workers_reset_data ();
2351 if (objects_pinned) {
2352 sgen_optimize_pin_queue ();
2353 sgen_pinning_setup_section (nursery_section);
2356 /* walk the pin_queue, build up the fragment list of free memory, unmark
2357 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2360 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2361 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2362 if (!fragment_total)
2365 /* Clear TLABs for all threads */
2366 sgen_clear_tlabs ();
2368 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2370 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2371 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2373 if (consistency_check_at_minor_collection)
2374 sgen_check_major_refs ();
2376 major_collector.finish_nursery_collection ();
2378 TV_GETTIME (last_minor_collection_end_tv);
2379 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2382 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2384 /* prepare the pin queue for the next collection */
2385 sgen_finish_pinning ();
2386 if (fin_ready_list || critical_fin_list) {
2387 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2388 mono_gc_finalize_notify ();
2390 sgen_pin_stats_reset ();
2391 /* clear cemented hash */
2392 sgen_cement_clear_below_threshold ();
2394 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2396 remset.finish_minor_collection ();
2398 check_scan_starts ();
2400 binary_protocol_flush_buffers (FALSE);
2402 sgen_memgov_minor_collection_end ();
2404 /*objects are late pinned because of lack of memory, so a major is a good call*/
2405 needs_major = objects_pinned > 0;
2406 current_collection_generation = -1;
2409 MONO_GC_END (GENERATION_NURSERY);
2410 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
2412 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2413 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2419 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2422 * This is called on all objects in the nursery, including pinned ones, so we need
2423 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2425 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2429 scan_nursery_objects (ScanCopyContext ctx)
2431 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2432 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2436 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)
2441 /* FIXME: only use these values for the precise scan
2442 * note that to_space pointers should be excluded anyway...
2444 char *heap_start = NULL;
2445 char *heap_end = (char*)-1;
2446 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2447 GCRootReport root_report = { 0 };
2448 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2449 ScanThreadDataJobData *stdjd;
2450 ScanCopyContext ctx;
2452 if (concurrent_collection_in_progress) {
2453 /*This cleans up unused fragments */
2454 sgen_nursery_allocator_prepare_for_pinning ();
2456 if (do_concurrent_checks)
2457 check_nursery_is_clean ();
2459 /* The concurrent collector doesn't touch the nursery. */
2460 sgen_nursery_alloc_prepare_for_major ();
2467 /* Pinning depends on this */
2468 sgen_clear_nursery_fragments ();
2470 if (whole_heap_check_before_collection)
2471 sgen_check_whole_heap (finish_up_concurrent_mark);
2474 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2476 if (!sgen_collection_is_concurrent ())
2477 nursery_section->next_data = sgen_get_nursery_end ();
2478 /* we should also coalesce scanning from sections close to each other
2479 * and deal with pointers outside of the sections later.
2484 if (xdomain_checks) {
2485 sgen_clear_nursery_fragments ();
2486 sgen_check_for_xdomain_refs ();
2489 if (!concurrent_collection_in_progress) {
2490 /* Remsets are not useful for a major collection */
2491 remset.clear_cards ();
2494 sgen_process_fin_stage_entries ();
2495 sgen_process_dislink_stage_entries ();
2498 sgen_init_pinning ();
2499 SGEN_LOG (6, "Collecting pinned addresses");
2500 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2502 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2503 if (major_collector.is_concurrent) {
2505 * The concurrent major collector cannot evict
2506 * yet, so we need to pin cemented objects to
2507 * not break some asserts.
2509 * FIXME: We could evict now!
2511 sgen_pin_cemented_objects ();
2515 sgen_optimize_pin_queue ();
2518 * pin_queue now contains all candidate pointers, sorted and
2519 * uniqued. We must do two passes now to figure out which
2520 * objects are pinned.
2522 * The first is to find within the pin_queue the area for each
2523 * section. This requires that the pin_queue be sorted. We
2524 * also process the LOS objects and pinned chunks here.
2526 * The second, destructive, pass is to reduce the section
2527 * areas to pointers to the actually pinned objects.
2529 SGEN_LOG (6, "Pinning from sections");
2530 /* first pass for the sections */
2531 sgen_find_section_pin_queue_start_end (nursery_section);
2532 /* identify possible pointers to the insize of large objects */
2533 SGEN_LOG (6, "Pinning from large objects");
2534 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2536 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2537 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2539 #ifdef ENABLE_DTRACE
2540 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2541 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2542 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2546 if (sgen_los_object_is_pinned (bigobj->data)) {
2547 g_assert (finish_up_concurrent_mark);
2550 sgen_los_pin_object (bigobj->data);
2551 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2552 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2553 if (G_UNLIKELY (do_pin_stats))
2554 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2555 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));
2558 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2562 notify_gc_roots (&root_report);
2563 /* second pass for the sections */
2564 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2565 ctx.copy_func = NULL;
2566 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2569 * Concurrent mark never follows references into the nursery. In the start and
2570 * finish pauses we must scan live nursery objects, though.
2572 * In the finish pause we do this conservatively by scanning all nursery objects.
2573 * Previously we would only scan pinned objects here. We assumed that all objects
2574 * that were pinned during the nursery collection immediately preceding this finish
2575 * mark would be pinned again here. Due to the way we get the stack end for the GC
2576 * thread, however, that's not necessarily the case: we scan part of the stack used
2577 * by the GC itself, which changes constantly, so pinning isn't entirely
2580 * The split nursery also complicates things because non-pinned objects can survive
2581 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2583 * In the future we shouldn't do a preceding nursery collection at all and instead
2584 * do the finish pause with promotion from the nursery.
2586 * A further complication arises when we have late-pinned objects from the preceding
2587 * nursery collection. Those are the result of being out of memory when trying to
2588 * evacuate objects. They won't be found from the roots, so we just scan the whole
2591 * Non-concurrent mark evacuates from the nursery, so it's
2592 * sufficient to just scan pinned nursery objects.
2594 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2595 scan_nursery_objects (ctx);
2597 pin_objects_in_nursery (ctx);
2598 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2599 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2602 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2603 if (old_next_pin_slot)
2604 *old_next_pin_slot = sgen_get_pinned_count ();
2607 time_major_pinning += TV_ELAPSED (atv, btv);
2608 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2609 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2611 major_collector.init_to_space ();
2614 * The concurrent collector doesn't move objects, neither on
2615 * the major heap nor in the nursery, so we can mark even
2616 * before pinning has finished. For the non-concurrent
2617 * collector we start the workers after pinning.
2619 if (start_concurrent_mark) {
2620 sgen_workers_start_all_workers ();
2621 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2624 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2625 main_gc_thread = mono_native_thread_self ();
2628 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2629 report_registered_roots ();
2631 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2633 /* registered roots, this includes static fields */
2634 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2635 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2636 scrrjd_normal->scan_func = current_object_ops.scan_object;
2637 scrrjd_normal->heap_start = heap_start;
2638 scrrjd_normal->heap_end = heap_end;
2639 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2640 sgen_workers_enqueue_job ("scan from registered roots normal", job_scan_from_registered_roots, scrrjd_normal);
2642 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2643 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2644 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2645 scrrjd_wbarrier->heap_start = heap_start;
2646 scrrjd_wbarrier->heap_end = heap_end;
2647 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2648 sgen_workers_enqueue_job ("scan from registered roots wbarrier", job_scan_from_registered_roots, scrrjd_wbarrier);
2651 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2654 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2655 stdjd->heap_start = heap_start;
2656 stdjd->heap_end = heap_end;
2657 sgen_workers_enqueue_job ("scan thread data", job_scan_thread_data, stdjd);
2660 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2663 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2665 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2666 report_finalizer_roots ();
2668 /* scan the list of objects ready for finalization */
2669 sgen_workers_enqueue_job ("scan finalizer entries", job_scan_finalizer_entries, fin_ready_list);
2670 sgen_workers_enqueue_job ("scan critical finalizer entries", job_scan_finalizer_entries, critical_fin_list);
2672 if (scan_mod_union) {
2673 g_assert (finish_up_concurrent_mark);
2675 /* Mod union card table */
2676 sgen_workers_enqueue_job ("scan mod union cardtable", job_scan_major_mod_union_cardtable, NULL);
2677 sgen_workers_enqueue_job ("scan LOS mod union cardtable", job_scan_los_mod_union_cardtable, NULL);
2681 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2682 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2685 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2689 major_finish_copy_or_mark (void)
2691 if (!concurrent_collection_in_progress)
2695 * Prepare the pin queue for the next collection. Since pinning runs on the worker
2696 * threads we must wait for the jobs to finish before we can reset it.
2698 sgen_workers_wait_for_jobs_finished ();
2699 sgen_finish_pinning ();
2701 sgen_pin_stats_reset ();
2703 if (do_concurrent_checks)
2704 check_nursery_is_clean ();
2708 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2710 MONO_GC_BEGIN (GENERATION_OLD);
2711 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2713 current_collection_generation = GENERATION_OLD;
2714 #ifndef DISABLE_PERFCOUNTERS
2715 mono_perfcounters->gc_collections1++;
2718 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2720 sgen_cement_reset ();
2723 g_assert (major_collector.is_concurrent);
2724 concurrent_collection_in_progress = TRUE;
2726 current_object_ops = major_collector.major_concurrent_ops;
2728 current_object_ops = major_collector.major_ops;
2731 reset_pinned_from_failed_allocation ();
2733 sgen_memgov_major_collection_start ();
2735 //count_ref_nonref_objs ();
2736 //consistency_check ();
2738 check_scan_starts ();
2741 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2742 gc_stats.major_gc_count ++;
2744 if (major_collector.start_major_collection)
2745 major_collector.start_major_collection ();
2747 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent, FALSE, FALSE, FALSE);
2748 major_finish_copy_or_mark ();
2752 wait_for_workers_to_finish (void)
2754 while (!sgen_workers_all_done ())
2759 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_whole_nursery)
2761 ScannedObjectCounts counts;
2762 LOSObject *bigobj, *prevbo;
2768 if (concurrent_collection_in_progress) {
2769 sgen_workers_signal_start_nursery_collection_and_wait ();
2771 current_object_ops = major_collector.major_concurrent_ops;
2773 major_copy_or_mark_from_roots (NULL, FALSE, TRUE, TRUE, scan_whole_nursery);
2775 sgen_workers_signal_finish_nursery_collection ();
2777 major_finish_copy_or_mark ();
2778 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2780 sgen_workers_join ();
2782 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2784 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2785 main_gc_thread = NULL;
2788 if (do_concurrent_checks)
2789 check_nursery_is_clean ();
2791 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2792 current_object_ops = major_collector.major_ops;
2796 * The workers have stopped so we need to finish gray queue
2797 * work that might result from finalization in the main GC
2798 * thread. Redirection must therefore be turned off.
2800 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2801 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2803 /* all the objects in the heap */
2804 finish_gray_stack (GENERATION_OLD, &gray_queue);
2806 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2808 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2811 * The (single-threaded) finalization code might have done
2812 * some copying/marking so we can only reset the GC thread's
2813 * worker data here instead of earlier when we joined the
2816 sgen_workers_reset_data ();
2818 if (objects_pinned) {
2819 g_assert (!concurrent_collection_in_progress);
2822 * This is slow, but we just OOM'd.
2824 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2825 * queue is laid out at this point.
2827 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2829 * We need to reestablish all pinned nursery objects in the pin queue
2830 * because they're needed for fragment creation. Unpinning happens by
2831 * walking the whole queue, so it's not necessary to reestablish where major
2832 * heap block pins are - all we care is that they're still in there
2835 sgen_optimize_pin_queue ();
2836 sgen_find_section_pin_queue_start_end (nursery_section);
2840 reset_heap_boundaries ();
2841 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2843 if (!concurrent_collection_in_progress) {
2844 /* walk the pin_queue, build up the fragment list of free memory, unmark
2845 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2848 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2851 /* prepare the pin queue for the next collection */
2852 sgen_finish_pinning ();
2854 /* Clear TLABs for all threads */
2855 sgen_clear_tlabs ();
2857 sgen_pin_stats_reset ();
2860 sgen_cement_clear_below_threshold ();
2862 if (check_mark_bits_after_major_collection)
2863 sgen_check_heap_marked (concurrent_collection_in_progress);
2866 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2869 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2871 /* sweep the big objects list */
2873 for (bigobj = los_object_list; bigobj;) {
2874 g_assert (!object_is_pinned (bigobj->data));
2875 if (sgen_los_object_is_pinned (bigobj->data)) {
2876 sgen_los_unpin_object (bigobj->data);
2877 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2880 /* not referenced anywhere, so we can free it */
2882 prevbo->next = bigobj->next;
2884 los_object_list = bigobj->next;
2886 bigobj = bigobj->next;
2887 sgen_los_free_object (to_free);
2891 bigobj = bigobj->next;
2895 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2900 time_major_los_sweep += TV_ELAPSED (atv, btv);
2902 major_collector.sweep ();
2904 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2907 time_major_sweep += TV_ELAPSED (btv, atv);
2910 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2912 if (fin_ready_list || critical_fin_list) {
2913 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2914 mono_gc_finalize_notify ();
2917 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2919 sgen_memgov_major_collection_end ();
2920 current_collection_generation = -1;
2922 memset (&counts, 0, sizeof (ScannedObjectCounts));
2923 major_collector.finish_major_collection (&counts);
2925 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2927 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2928 if (concurrent_collection_in_progress)
2929 concurrent_collection_in_progress = FALSE;
2931 check_scan_starts ();
2933 binary_protocol_flush_buffers (FALSE);
2935 //consistency_check ();
2937 MONO_GC_END (GENERATION_OLD);
2938 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2942 major_do_collection (const char *reason)
2944 TV_DECLARE (time_start);
2945 TV_DECLARE (time_end);
2946 size_t old_next_pin_slot;
2948 if (disable_major_collections)
2951 if (major_collector.get_and_reset_num_major_objects_marked) {
2952 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2953 g_assert (!num_marked);
2956 /* world must be stopped already */
2957 TV_GETTIME (time_start);
2959 major_start_collection (FALSE, &old_next_pin_slot);
2960 major_finish_collection (reason, old_next_pin_slot, FALSE);
2962 TV_GETTIME (time_end);
2963 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2965 /* FIXME: also report this to the user, preferably in gc-end. */
2966 if (major_collector.get_and_reset_num_major_objects_marked)
2967 major_collector.get_and_reset_num_major_objects_marked ();
2969 return bytes_pinned_from_failed_allocation > 0;
2973 major_start_concurrent_collection (const char *reason)
2975 TV_DECLARE (time_start);
2976 TV_DECLARE (time_end);
2977 long long num_objects_marked;
2979 if (disable_major_collections)
2982 TV_GETTIME (time_start);
2983 SGEN_TV_GETTIME (time_major_conc_collection_start);
2985 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2986 g_assert (num_objects_marked == 0);
2988 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
2989 binary_protocol_concurrent_start ();
2991 // FIXME: store reason and pass it when finishing
2992 major_start_collection (TRUE, NULL);
2994 gray_queue_redirect (&gray_queue);
2996 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2997 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
2999 TV_GETTIME (time_end);
3000 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3002 current_collection_generation = -1;
3006 * Returns whether the major collection has finished.
3009 major_should_finish_concurrent_collection (void)
3011 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
3012 return sgen_workers_all_done ();
3016 major_update_concurrent_collection (void)
3018 TV_DECLARE (total_start);
3019 TV_DECLARE (total_end);
3021 TV_GETTIME (total_start);
3023 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3024 binary_protocol_concurrent_update ();
3026 major_collector.update_cardtable_mod_union ();
3027 sgen_los_update_cardtable_mod_union ();
3029 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3031 TV_GETTIME (total_end);
3032 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3036 major_finish_concurrent_collection (void)
3038 TV_DECLARE (total_start);
3039 TV_DECLARE (total_end);
3040 gboolean late_pinned;
3041 SgenGrayQueue unpin_queue;
3042 memset (&unpin_queue, 0, sizeof (unpin_queue));
3044 TV_GETTIME (total_start);
3046 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3047 binary_protocol_concurrent_finish ();
3050 * The major collector can add global remsets which are processed in the finishing
3051 * nursery collection, below. That implies that the workers must have finished
3052 * marking before the nursery collection is allowed to run, otherwise we might miss
3055 wait_for_workers_to_finish ();
3057 SGEN_TV_GETTIME (time_major_conc_collection_end);
3058 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3060 major_collector.update_cardtable_mod_union ();
3061 sgen_los_update_cardtable_mod_union ();
3063 late_pinned = collect_nursery (&unpin_queue, TRUE);
3065 if (mod_union_consistency_check)
3066 sgen_check_mod_union_consistency ();
3068 current_collection_generation = GENERATION_OLD;
3069 major_finish_collection ("finishing", -1, late_pinned);
3071 if (whole_heap_check_before_collection)
3072 sgen_check_whole_heap (FALSE);
3074 unpin_objects_from_queue (&unpin_queue);
3075 sgen_gray_object_queue_deinit (&unpin_queue);
3077 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3079 TV_GETTIME (total_end);
3080 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3082 current_collection_generation = -1;
3086 * Ensure an allocation request for @size will succeed by freeing enough memory.
3088 * LOCKING: The GC lock MUST be held.
3091 sgen_ensure_free_space (size_t size)
3093 int generation_to_collect = -1;
3094 const char *reason = NULL;
3097 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3098 if (sgen_need_major_collection (size)) {
3099 reason = "LOS overflow";
3100 generation_to_collect = GENERATION_OLD;
3103 if (degraded_mode) {
3104 if (sgen_need_major_collection (size)) {
3105 reason = "Degraded mode overflow";
3106 generation_to_collect = GENERATION_OLD;
3108 } else if (sgen_need_major_collection (size)) {
3109 reason = "Minor allowance";
3110 generation_to_collect = GENERATION_OLD;
3112 generation_to_collect = GENERATION_NURSERY;
3113 reason = "Nursery full";
3117 if (generation_to_collect == -1) {
3118 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3119 generation_to_collect = GENERATION_OLD;
3120 reason = "Finish concurrent collection";
3124 if (generation_to_collect == -1)
3126 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3130 * LOCKING: Assumes the GC lock is held.
3133 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3135 TV_DECLARE (gc_start);
3136 TV_DECLARE (gc_end);
3137 TV_DECLARE (gc_total_start);
3138 TV_DECLARE (gc_total_end);
3139 GGTimingInfo infos [2];
3140 int overflow_generation_to_collect = -1;
3141 int oldest_generation_collected = generation_to_collect;
3142 const char *overflow_reason = NULL;
3144 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3146 binary_protocol_collection_force (generation_to_collect);
3148 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3150 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3152 TV_GETTIME (gc_start);
3154 sgen_stop_world (generation_to_collect);
3156 TV_GETTIME (gc_total_start);
3158 if (concurrent_collection_in_progress) {
3160 * We update the concurrent collection. If it finished, we're done. If
3161 * not, and we've been asked to do a nursery collection, we do that.
3163 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3166 major_finish_concurrent_collection ();
3167 oldest_generation_collected = GENERATION_OLD;
3169 sgen_workers_signal_start_nursery_collection_and_wait ();
3171 major_update_concurrent_collection ();
3172 if (generation_to_collect == GENERATION_NURSERY)
3173 collect_nursery (NULL, FALSE);
3175 sgen_workers_signal_finish_nursery_collection ();
3182 * If we've been asked to do a major collection, and the major collector wants to
3183 * run synchronously (to evacuate), we set the flag to do that.
3185 if (generation_to_collect == GENERATION_OLD &&
3186 allow_synchronous_major &&
3187 major_collector.want_synchronous_collection &&
3188 *major_collector.want_synchronous_collection) {
3189 wait_to_finish = TRUE;
3192 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3195 * There's no concurrent collection in progress. Collect the generation we're asked
3196 * to collect. If the major collector is concurrent and we're not forced to wait,
3197 * start a concurrent collection.
3199 // FIXME: extract overflow reason
3200 if (generation_to_collect == GENERATION_NURSERY) {
3201 if (collect_nursery (NULL, FALSE)) {
3202 overflow_generation_to_collect = GENERATION_OLD;
3203 overflow_reason = "Minor overflow";
3206 if (major_collector.is_concurrent && !wait_to_finish) {
3207 collect_nursery (NULL, FALSE);
3208 major_start_concurrent_collection (reason);
3209 // FIXME: set infos[0] properly
3213 if (major_do_collection (reason)) {
3214 overflow_generation_to_collect = GENERATION_NURSERY;
3215 overflow_reason = "Excessive pinning";
3219 TV_GETTIME (gc_end);
3221 memset (infos, 0, sizeof (infos));
3222 infos [0].generation = generation_to_collect;
3223 infos [0].reason = reason;
3224 infos [0].is_overflow = FALSE;
3225 infos [1].generation = -1;
3226 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3228 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3230 if (overflow_generation_to_collect != -1) {
3232 * We need to do an overflow collection, either because we ran out of memory
3233 * or the nursery is fully pinned.
3236 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3237 infos [1].generation = overflow_generation_to_collect;
3238 infos [1].reason = overflow_reason;
3239 infos [1].is_overflow = TRUE;
3240 infos [1].total_time = gc_end;
3242 if (overflow_generation_to_collect == GENERATION_NURSERY)
3243 collect_nursery (NULL, FALSE);
3245 major_do_collection (overflow_reason);
3247 TV_GETTIME (gc_end);
3248 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3250 /* keep events symmetric */
3251 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3253 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3256 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3258 /* this also sets the proper pointers for the next allocation */
3259 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3260 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3261 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3262 sgen_dump_pin_queue ();
3267 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3269 TV_GETTIME (gc_total_end);
3270 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3272 sgen_restart_world (oldest_generation_collected, infos);
3274 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3278 * ######################################################################
3279 * ######## Memory allocation from the OS
3280 * ######################################################################
3281 * This section of code deals with getting memory from the OS and
3282 * allocating memory for GC-internal data structures.
3283 * Internal memory can be handled with a freelist for small objects.
3289 G_GNUC_UNUSED static void
3290 report_internal_mem_usage (void)
3292 printf ("Internal memory usage:\n");
3293 sgen_report_internal_mem_usage ();
3294 printf ("Pinned memory usage:\n");
3295 major_collector.report_pinned_memory_usage ();
3299 * ######################################################################
3300 * ######## Finalization support
3301 * ######################################################################
3304 static inline gboolean
3305 sgen_major_is_object_alive (void *object)
3309 /* Oldgen objects can be pinned and forwarded too */
3310 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3314 * FIXME: major_collector.is_object_live() also calculates the
3315 * size. Avoid the double calculation.
3317 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3318 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3319 return sgen_los_object_is_pinned (object);
3321 return major_collector.is_object_live (object);
3325 * If the object has been forwarded it means it's still referenced from a root.
3326 * If it is pinned it's still alive as well.
3327 * A LOS object is only alive if we have pinned it.
3328 * Return TRUE if @obj is ready to be finalized.
3330 static inline gboolean
3331 sgen_is_object_alive (void *object)
3333 if (ptr_in_nursery (object))
3334 return sgen_nursery_is_object_alive (object);
3336 return sgen_major_is_object_alive (object);
3340 * This function returns true if @object is either alive or it belongs to the old gen
3341 * and we're currently doing a minor collection.
3344 sgen_is_object_alive_for_current_gen (char *object)
3346 if (ptr_in_nursery (object))
3347 return sgen_nursery_is_object_alive (object);
3349 if (current_collection_generation == GENERATION_NURSERY)
3352 return sgen_major_is_object_alive (object);
3356 * This function returns true if @object is either alive and belongs to the
3357 * current collection - major collections are full heap, so old gen objects
3358 * are never alive during a minor collection.
3361 sgen_is_object_alive_and_on_current_collection (char *object)
3363 if (ptr_in_nursery (object))
3364 return sgen_nursery_is_object_alive (object);
3366 if (current_collection_generation == GENERATION_NURSERY)
3369 return sgen_major_is_object_alive (object);
3374 sgen_gc_is_object_ready_for_finalization (void *object)
3376 return !sgen_is_object_alive (object);
3380 has_critical_finalizer (MonoObject *obj)
3384 if (!mono_defaults.critical_finalizer_object)
3387 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3389 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3393 is_finalization_aware (MonoObject *obj)
3395 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3396 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3400 sgen_queue_finalization_entry (MonoObject *obj)
3402 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3403 gboolean critical = has_critical_finalizer (obj);
3404 entry->object = obj;
3406 entry->next = critical_fin_list;
3407 critical_fin_list = entry;
3409 entry->next = fin_ready_list;
3410 fin_ready_list = entry;
3413 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3414 fin_callbacks.object_queued_for_finalization (obj);
3416 #ifdef ENABLE_DTRACE
3417 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3418 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3419 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3420 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3421 vt->klass->name_space, vt->klass->name, gen, critical);
3427 sgen_object_is_live (void *obj)
3429 return sgen_is_object_alive_and_on_current_collection (obj);
3432 /* LOCKING: requires that the GC lock is held */
3434 null_ephemerons_for_domain (MonoDomain *domain)
3436 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3439 MonoObject *object = (MonoObject*)current->array;
3442 SGEN_ASSERT (0, object->vtable, "Can't have objects without vtables.");
3444 if (object && object->vtable->domain == domain) {
3445 EphemeronLinkNode *tmp = current;
3448 prev->next = current->next;
3450 ephemeron_list = current->next;
3452 current = current->next;
3453 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3456 current = current->next;
3461 /* LOCKING: requires that the GC lock is held */
3463 clear_unreachable_ephemerons (ScanCopyContext ctx)
3465 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3466 GrayQueue *queue = ctx.queue;
3467 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3469 Ephemeron *cur, *array_end;
3473 char *object = current->array;
3475 if (!sgen_is_object_alive_for_current_gen (object)) {
3476 EphemeronLinkNode *tmp = current;
3478 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3481 prev->next = current->next;
3483 ephemeron_list = current->next;
3485 current = current->next;
3486 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3491 copy_func ((void**)&object, queue);
3492 current->array = object;
3494 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3496 array = (MonoArray*)object;
3497 cur = mono_array_addr (array, Ephemeron, 0);
3498 array_end = cur + mono_array_length_fast (array);
3499 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3501 for (; cur < array_end; ++cur) {
3502 char *key = (char*)cur->key;
3504 if (!key || key == tombstone)
3507 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3508 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3509 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3511 if (!sgen_is_object_alive_for_current_gen (key)) {
3512 cur->key = tombstone;
3518 current = current->next;
3523 LOCKING: requires that the GC lock is held
3525 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3528 mark_ephemerons_in_range (ScanCopyContext ctx)
3530 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3531 GrayQueue *queue = ctx.queue;
3532 int nothing_marked = 1;
3533 EphemeronLinkNode *current = ephemeron_list;
3535 Ephemeron *cur, *array_end;
3538 for (current = ephemeron_list; current; current = current->next) {
3539 char *object = current->array;
3540 SGEN_LOG (5, "Ephemeron array at %p", object);
3542 /*It has to be alive*/
3543 if (!sgen_is_object_alive_for_current_gen (object)) {
3544 SGEN_LOG (5, "\tnot reachable");
3548 copy_func ((void**)&object, queue);
3550 array = (MonoArray*)object;
3551 cur = mono_array_addr (array, Ephemeron, 0);
3552 array_end = cur + mono_array_length_fast (array);
3553 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3555 for (; cur < array_end; ++cur) {
3556 char *key = cur->key;
3558 if (!key || key == tombstone)
3561 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3562 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3563 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3565 if (sgen_is_object_alive_for_current_gen (key)) {
3566 char *value = cur->value;
3568 copy_func ((void**)&cur->key, queue);
3570 if (!sgen_is_object_alive_for_current_gen (value))
3572 copy_func ((void**)&cur->value, queue);
3578 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3579 return nothing_marked;
3583 mono_gc_invoke_finalizers (void)
3585 FinalizeReadyEntry *entry = NULL;
3586 gboolean entry_is_critical = FALSE;
3589 /* FIXME: batch to reduce lock contention */
3590 while (fin_ready_list || critical_fin_list) {
3594 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3596 /* We have finalized entry in the last
3597 interation, now we need to remove it from
3600 *list = entry->next;
3602 FinalizeReadyEntry *e = *list;
3603 while (e->next != entry)
3605 e->next = entry->next;
3607 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3611 /* Now look for the first non-null entry. */
3612 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3615 entry_is_critical = FALSE;
3617 entry_is_critical = TRUE;
3618 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3623 g_assert (entry->object);
3624 num_ready_finalizers--;
3625 obj = entry->object;
3626 entry->object = NULL;
3627 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3635 g_assert (entry->object == NULL);
3637 /* the object is on the stack so it is pinned */
3638 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3639 mono_gc_run_finalize (obj, NULL);
3646 mono_gc_pending_finalizers (void)
3648 return fin_ready_list || critical_fin_list;
3652 * ######################################################################
3653 * ######## registered roots support
3654 * ######################################################################
3658 * We do not coalesce roots.
3661 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3663 RootRecord new_root;
3666 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3667 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3668 /* we allow changing the size and the descriptor (for thread statics etc) */
3670 size_t old_size = root->end_root - start;
3671 root->end_root = start + size;
3672 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3673 ((root->root_desc == 0) && (descr == NULL)));
3674 root->root_desc = (mword)descr;
3676 roots_size -= old_size;
3682 new_root.end_root = start + size;
3683 new_root.root_desc = (mword)descr;
3685 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3688 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);
3695 mono_gc_register_root (char *start, size_t size, void *descr)
3697 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3701 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3703 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3707 mono_gc_deregister_root (char* addr)
3713 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3714 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3715 roots_size -= (root.end_root - addr);
3721 * ######################################################################
3722 * ######## Thread handling (stop/start code)
3723 * ######################################################################
3726 unsigned int sgen_global_stop_count = 0;
3729 sgen_get_current_collection_generation (void)
3731 return current_collection_generation;
3735 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3737 gc_callbacks = *callbacks;
3741 mono_gc_get_gc_callbacks ()
3743 return &gc_callbacks;
3746 /* Variables holding start/end nursery so it won't have to be passed at every call */
3747 static void *scan_area_arg_start, *scan_area_arg_end;
3750 mono_gc_conservatively_scan_area (void *start, void *end)
3752 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3756 mono_gc_scan_object (void *obj, void *gc_data)
3758 UserCopyOrMarkData *data = gc_data;
3759 current_object_ops.copy_or_mark_object (&obj, data->queue);
3764 * Mark from thread stacks and registers.
3767 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3769 SgenThreadInfo *info;
3771 scan_area_arg_start = start_nursery;
3772 scan_area_arg_end = end_nursery;
3774 FOREACH_THREAD (info) {
3776 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);
3779 if (info->gc_disabled) {
3780 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);
3783 if (!mono_thread_info_is_live (info)) {
3784 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);
3787 g_assert (info->suspend_done);
3788 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 ());
3789 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3790 UserCopyOrMarkData data = { NULL, queue };
3791 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3792 } else if (!precise) {
3793 if (!conservative_stack_mark) {
3794 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3795 conservative_stack_mark = TRUE;
3797 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3802 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3803 start_nursery, end_nursery, PIN_TYPE_STACK);
3805 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3806 start_nursery, end_nursery, PIN_TYPE_STACK);
3809 } END_FOREACH_THREAD
3813 ptr_on_stack (void *ptr)
3815 gpointer stack_start = &stack_start;
3816 SgenThreadInfo *info = mono_thread_info_current ();
3818 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3824 sgen_thread_register (SgenThreadInfo* info, void *addr)
3827 guint8 *staddr = NULL;
3829 #ifndef HAVE_KW_THREAD
3830 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3832 g_assert (!mono_native_tls_get_value (thread_info_key));
3833 mono_native_tls_set_value (thread_info_key, info);
3835 sgen_thread_info = info;
3838 #ifdef SGEN_POSIX_STW
3839 info->stop_count = -1;
3843 info->stack_start = NULL;
3844 info->stopped_ip = NULL;
3845 info->stopped_domain = NULL;
3847 memset (&info->ctx, 0, sizeof (MonoContext));
3849 memset (&info->regs, 0, sizeof (info->regs));
3852 sgen_init_tlab_info (info);
3854 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3856 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3857 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3860 info->stack_start_limit = staddr;
3862 info->stack_end = staddr + stsize;
3864 gsize stack_bottom = (gsize)addr;
3865 stack_bottom += 4095;
3866 stack_bottom &= ~4095;
3867 info->stack_end = (char*)stack_bottom;
3870 #ifdef HAVE_KW_THREAD
3871 stack_end = info->stack_end;
3874 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3876 if (gc_callbacks.thread_attach_func)
3877 info->runtime_data = gc_callbacks.thread_attach_func ();
3882 sgen_thread_detach (SgenThreadInfo *p)
3884 /* If a delegate is passed to native code and invoked on a thread we dont
3885 * know about, the jit will register it with mono_jit_thread_attach, but
3886 * we have no way of knowing when that thread goes away. SGen has a TSD
3887 * so we assume that if the domain is still registered, we can detach
3890 if (mono_domain_get ())
3891 mono_thread_detach_internal (mono_thread_internal_current ());
3895 sgen_thread_unregister (SgenThreadInfo *p)
3897 MonoNativeThreadId tid;
3899 tid = mono_thread_info_get_tid (p);
3900 binary_protocol_thread_unregister ((gpointer)tid);
3901 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3903 #ifndef HAVE_KW_THREAD
3904 mono_native_tls_set_value (thread_info_key, NULL);
3906 sgen_thread_info = NULL;
3909 if (p->info.runtime_thread)
3910 mono_threads_add_joinable_thread ((gpointer)tid);
3912 if (gc_callbacks.thread_detach_func) {
3913 gc_callbacks.thread_detach_func (p->runtime_data);
3914 p->runtime_data = NULL;
3920 sgen_thread_attach (SgenThreadInfo *info)
3923 /*this is odd, can we get attached before the gc is inited?*/
3927 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3928 info->runtime_data = gc_callbacks.thread_attach_func ();
3931 mono_gc_register_thread (void *baseptr)
3933 return mono_thread_info_attach (baseptr) != NULL;
3937 * mono_gc_set_stack_end:
3939 * Set the end of the current threads stack to STACK_END. The stack space between
3940 * STACK_END and the real end of the threads stack will not be scanned during collections.
3943 mono_gc_set_stack_end (void *stack_end)
3945 SgenThreadInfo *info;
3948 info = mono_thread_info_current ();
3950 g_assert (stack_end < info->stack_end);
3951 info->stack_end = stack_end;
3956 #if USE_PTHREAD_INTERCEPT
3960 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3962 return pthread_create (new_thread, attr, start_routine, arg);
3966 mono_gc_pthread_join (pthread_t thread, void **retval)
3968 return pthread_join (thread, retval);
3972 mono_gc_pthread_detach (pthread_t thread)
3974 return pthread_detach (thread);
3978 mono_gc_pthread_exit (void *retval)
3980 mono_thread_info_detach ();
3981 pthread_exit (retval);
3982 g_assert_not_reached ();
3985 #endif /* USE_PTHREAD_INTERCEPT */
3988 * ######################################################################
3989 * ######## Write barriers
3990 * ######################################################################
3994 * Note: the write barriers first do the needed GC work and then do the actual store:
3995 * this way the value is visible to the conservative GC scan after the write barrier
3996 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
3997 * the conservative scan, otherwise by the remembered set scan.
4000 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4002 HEAVY_STAT (++stat_wbarrier_set_field);
4003 if (ptr_in_nursery (field_ptr)) {
4004 *(void**)field_ptr = value;
4007 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4009 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4011 remset.wbarrier_set_field (obj, field_ptr, value);
4015 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4017 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4018 if (ptr_in_nursery (slot_ptr)) {
4019 *(void**)slot_ptr = value;
4022 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4024 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4026 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4030 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4032 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4033 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4034 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4035 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4039 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4040 if (binary_protocol_is_heavy_enabled ()) {
4042 for (i = 0; i < count; ++i) {
4043 gpointer dest = (gpointer*)dest_ptr + i;
4044 gpointer obj = *((gpointer*)src_ptr + i);
4046 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4051 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4055 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4059 HEAVY_STAT (++stat_wbarrier_generic_store);
4061 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4062 /* FIXME: ptr_in_heap must be called with the GC lock held */
4063 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4064 char *start = sgen_find_object_for_ptr (ptr);
4065 MonoObject *value = *(MonoObject**)ptr;
4069 MonoObject *obj = (MonoObject*)start;
4070 if (obj->vtable->domain != value->vtable->domain)
4071 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4077 obj = *(gpointer*)ptr;
4079 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4081 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4082 SGEN_LOG (8, "Skipping remset at %p", ptr);
4087 * We need to record old->old pointer locations for the
4088 * concurrent collector.
4090 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4091 SGEN_LOG (8, "Skipping remset at %p", ptr);
4095 SGEN_LOG (8, "Adding remset at %p", ptr);
4097 remset.wbarrier_generic_nostore (ptr);
4101 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4103 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4104 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4105 if (ptr_in_nursery (value))
4106 mono_gc_wbarrier_generic_nostore (ptr);
4107 sgen_dummy_use (value);
4110 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4111 * as an atomic operation with release semantics.
4114 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4116 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4118 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4120 InterlockedWritePointer (ptr, value);
4122 if (ptr_in_nursery (value))
4123 mono_gc_wbarrier_generic_nostore (ptr);
4125 sgen_dummy_use (value);
4128 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4130 mword *dest = _dest;
4135 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4137 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4140 size -= SIZEOF_VOID_P;
4145 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4147 #define HANDLE_PTR(ptr,obj) do { \
4148 gpointer o = *(gpointer*)(ptr); \
4150 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4151 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4156 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4158 #define SCAN_OBJECT_NOVTABLE
4159 #include "sgen-scan-object.h"
4164 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4166 HEAVY_STAT (++stat_wbarrier_value_copy);
4167 g_assert (klass->valuetype);
4169 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4171 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4172 size_t element_size = mono_class_value_size (klass, NULL);
4173 size_t size = count * element_size;
4174 mono_gc_memmove_atomic (dest, src, size);
4178 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4179 if (binary_protocol_is_heavy_enabled ()) {
4180 size_t element_size = mono_class_value_size (klass, NULL);
4182 for (i = 0; i < count; ++i) {
4183 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4184 (char*)src + i * element_size - sizeof (MonoObject),
4185 (mword) klass->gc_descr);
4190 remset.wbarrier_value_copy (dest, src, count, klass);
4194 * mono_gc_wbarrier_object_copy:
4196 * Write barrier to call when obj is the result of a clone or copy of an object.
4199 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4203 HEAVY_STAT (++stat_wbarrier_object_copy);
4205 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4206 size = mono_object_class (obj)->instance_size;
4207 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4208 size - sizeof (MonoObject));
4212 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4213 if (binary_protocol_is_heavy_enabled ())
4214 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4217 remset.wbarrier_object_copy (obj, src);
4222 * ######################################################################
4223 * ######## Other mono public interface functions.
4224 * ######################################################################
4227 #define REFS_SIZE 128
4230 MonoGCReferences callback;
4234 MonoObject *refs [REFS_SIZE];
4235 uintptr_t offsets [REFS_SIZE];
4239 #define HANDLE_PTR(ptr,obj) do { \
4241 if (hwi->count == REFS_SIZE) { \
4242 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4246 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4247 hwi->refs [hwi->count++] = *(ptr); \
4252 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4254 mword desc = sgen_obj_get_descriptor (start);
4256 #include "sgen-scan-object.h"
4260 walk_references (char *start, size_t size, void *data)
4262 HeapWalkInfo *hwi = data;
4265 collect_references (hwi, start, size);
4266 if (hwi->count || !hwi->called)
4267 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4271 * mono_gc_walk_heap:
4272 * @flags: flags for future use
4273 * @callback: a function pointer called for each object in the heap
4274 * @data: a user data pointer that is passed to callback
4276 * This function can be used to iterate over all the live objects in the heap:
4277 * for each object, @callback is invoked, providing info about the object's
4278 * location in memory, its class, its size and the objects it references.
4279 * For each referenced object it's offset from the object address is
4280 * reported in the offsets array.
4281 * The object references may be buffered, so the callback may be invoked
4282 * multiple times for the same object: in all but the first call, the size
4283 * argument will be zero.
4284 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4285 * profiler event handler.
4287 * Returns: a non-zero value if the GC doesn't support heap walking
4290 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4295 hwi.callback = callback;
4298 sgen_clear_nursery_fragments ();
4299 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4301 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4302 sgen_los_iterate_objects (walk_references, &hwi);
4308 mono_gc_collect (int generation)
4313 sgen_perform_collection (0, generation, "user request", TRUE);
4318 mono_gc_max_generation (void)
4324 mono_gc_collection_count (int generation)
4326 if (generation == 0)
4327 return gc_stats.minor_gc_count;
4328 return gc_stats.major_gc_count;
4332 mono_gc_get_used_size (void)
4336 tot = los_memory_usage;
4337 tot += nursery_section->next_data - nursery_section->data;
4338 tot += major_collector.get_used_size ();
4339 /* FIXME: account for pinned objects */
4345 mono_gc_get_los_limit (void)
4347 return MAX_SMALL_OBJ_SIZE;
4351 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4353 mono_unichar2 *new_end = str->chars + new_length;
4355 /* zero the discarded string. This null-delimits the string and allows
4356 * the space to be reclaimed by SGen. */
4358 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4359 CHECK_CANARY_FOR_OBJECT (str);
4360 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4361 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4363 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4366 str->length = new_length;
4370 mono_gc_user_markers_supported (void)
4376 mono_object_is_alive (MonoObject* o)
4382 mono_gc_get_generation (MonoObject *obj)
4384 if (ptr_in_nursery (obj))
4390 mono_gc_enable_events (void)
4395 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4397 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4401 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4403 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4407 mono_gc_weak_link_get (void **link_addr)
4409 void * volatile *link_addr_volatile;
4413 link_addr_volatile = link_addr;
4414 ptr = (void*)*link_addr_volatile;
4416 * At this point we have a hidden pointer. If the GC runs
4417 * here, it will not recognize the hidden pointer as a
4418 * reference, and if the object behind it is not referenced
4419 * elsewhere, it will be freed. Once the world is restarted
4420 * we reveal the pointer, giving us a pointer to a freed
4421 * object. To make sure we don't return it, we load the
4422 * hidden pointer again. If it's still the same, we can be
4423 * sure the object reference is valid.
4426 obj = (MonoObject*) REVEAL_POINTER (ptr);
4430 mono_memory_barrier ();
4433 * During the second bridge processing step the world is
4434 * running again. That step processes all weak links once
4435 * more to null those that refer to dead objects. Before that
4436 * is completed, those links must not be followed, so we
4437 * conservatively wait for bridge processing when any weak
4438 * link is dereferenced.
4440 if (G_UNLIKELY (bridge_processing_in_progress))
4441 mono_gc_wait_for_bridge_processing ();
4443 if ((void*)*link_addr_volatile != ptr)
4450 mono_gc_ephemeron_array_add (MonoObject *obj)
4452 EphemeronLinkNode *node;
4456 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4461 node->array = (char*)obj;
4462 node->next = ephemeron_list;
4463 ephemeron_list = node;
4465 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4472 mono_gc_set_allow_synchronous_major (gboolean flag)
4474 if (!major_collector.is_concurrent)
4477 allow_synchronous_major = flag;
4482 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4486 result = func (data);
4487 UNLOCK_INTERRUPTION;
4492 mono_gc_is_gc_thread (void)
4496 result = mono_thread_info_current () != NULL;
4502 is_critical_method (MonoMethod *method)
4504 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4508 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4512 va_start (ap, description_format);
4514 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4515 vfprintf (stderr, description_format, ap);
4517 fprintf (stderr, " - %s", fallback);
4518 fprintf (stderr, "\n");
4524 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4527 double val = strtod (opt, &endptr);
4528 if (endptr == opt) {
4529 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4532 else if (val < min || val > max) {
4533 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4541 thread_in_critical_region (SgenThreadInfo *info)
4543 return info->in_critical_region;
4547 mono_gc_base_init (void)
4549 MonoThreadInfoCallbacks cb;
4552 char *major_collector_opt = NULL;
4553 char *minor_collector_opt = NULL;
4554 size_t max_heap = 0;
4555 size_t soft_limit = 0;
4558 gboolean debug_print_allowance = FALSE;
4559 double allowance_ratio = 0, save_target = 0;
4560 gboolean cement_enabled = TRUE;
4562 mono_counters_init ();
4565 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4568 /* already inited */
4571 /* being inited by another thread */
4575 /* we will init it */
4578 g_assert_not_reached ();
4580 } while (result != 0);
4582 SGEN_TV_GETTIME (sgen_init_timestamp);
4584 LOCK_INIT (gc_mutex);
4586 pagesize = mono_pagesize ();
4587 gc_debug_file = stderr;
4589 cb.thread_register = sgen_thread_register;
4590 cb.thread_detach = sgen_thread_detach;
4591 cb.thread_unregister = sgen_thread_unregister;
4592 cb.thread_attach = sgen_thread_attach;
4593 cb.mono_method_is_critical = (gpointer)is_critical_method;
4594 cb.mono_thread_in_critical_region = thread_in_critical_region;
4596 cb.thread_exit = mono_gc_pthread_exit;
4597 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4600 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4602 LOCK_INIT (sgen_interruption_mutex);
4604 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4605 opts = g_strsplit (env, ",", -1);
4606 for (ptr = opts; *ptr; ++ptr) {
4608 if (g_str_has_prefix (opt, "major=")) {
4609 opt = strchr (opt, '=') + 1;
4610 major_collector_opt = g_strdup (opt);
4611 } else if (g_str_has_prefix (opt, "minor=")) {
4612 opt = strchr (opt, '=') + 1;
4613 minor_collector_opt = g_strdup (opt);
4621 sgen_init_internal_allocator ();
4622 sgen_init_nursery_allocator ();
4623 sgen_init_fin_weak_hash ();
4625 sgen_init_hash_table ();
4626 sgen_init_descriptors ();
4627 sgen_init_gray_queues ();
4629 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4630 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4631 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4632 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4634 #ifndef HAVE_KW_THREAD
4635 mono_native_tls_alloc (&thread_info_key, NULL);
4636 #if defined(__APPLE__) || defined (HOST_WIN32)
4638 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4639 * where the two are the same.
4641 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4645 int tls_offset = -1;
4646 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4647 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4652 * This needs to happen before any internal allocations because
4653 * it inits the small id which is required for hazard pointer
4658 mono_thread_info_attach (&dummy);
4660 if (!minor_collector_opt) {
4661 sgen_simple_nursery_init (&sgen_minor_collector);
4663 if (!strcmp (minor_collector_opt, "simple")) {
4665 sgen_simple_nursery_init (&sgen_minor_collector);
4666 } else if (!strcmp (minor_collector_opt, "split")) {
4667 sgen_split_nursery_init (&sgen_minor_collector);
4669 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4670 goto use_simple_nursery;
4674 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4675 use_marksweep_major:
4676 sgen_marksweep_init (&major_collector);
4677 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4678 sgen_marksweep_conc_init (&major_collector);
4680 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4681 goto use_marksweep_major;
4684 ///* Keep this the default for now */
4685 /* Precise marking is broken on all supported targets. Disable until fixed. */
4686 conservative_stack_mark = TRUE;
4688 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4690 if (major_collector.is_concurrent)
4691 cement_enabled = FALSE;
4694 gboolean usage_printed = FALSE;
4696 for (ptr = opts; *ptr; ++ptr) {
4698 if (!strcmp (opt, ""))
4700 if (g_str_has_prefix (opt, "major="))
4702 if (g_str_has_prefix (opt, "minor="))
4704 if (g_str_has_prefix (opt, "max-heap-size=")) {
4705 size_t max_heap_candidate = 0;
4706 opt = strchr (opt, '=') + 1;
4707 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4708 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4709 if (max_heap != max_heap_candidate)
4710 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4712 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4716 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4717 opt = strchr (opt, '=') + 1;
4718 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4719 if (soft_limit <= 0) {
4720 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4724 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4728 if (g_str_has_prefix (opt, "stack-mark=")) {
4729 opt = strchr (opt, '=') + 1;
4730 if (!strcmp (opt, "precise")) {
4731 conservative_stack_mark = FALSE;
4732 } else if (!strcmp (opt, "conservative")) {
4733 conservative_stack_mark = TRUE;
4735 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4736 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4740 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4741 opt = strchr (opt, '=') + 1;
4742 sgen_set_bridge_implementation (opt);
4745 if (g_str_has_prefix (opt, "toggleref-test")) {
4746 sgen_register_test_toggleref_callback ();
4751 if (g_str_has_prefix (opt, "nursery-size=")) {
4753 opt = strchr (opt, '=') + 1;
4754 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4755 if ((val & (val - 1))) {
4756 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4760 if (val < SGEN_MAX_NURSERY_WASTE) {
4761 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4762 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4766 sgen_nursery_size = val;
4767 sgen_nursery_bits = 0;
4768 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4771 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4777 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4779 opt = strchr (opt, '=') + 1;
4780 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4781 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4786 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4788 opt = strchr (opt, '=') + 1;
4789 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4790 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4791 allowance_ratio = val;
4795 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4796 if (!major_collector.is_concurrent) {
4797 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4801 opt = strchr (opt, '=') + 1;
4803 if (!strcmp (opt, "yes")) {
4804 allow_synchronous_major = TRUE;
4805 } else if (!strcmp (opt, "no")) {
4806 allow_synchronous_major = FALSE;
4808 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4813 if (!strcmp (opt, "cementing")) {
4814 cement_enabled = TRUE;
4817 if (!strcmp (opt, "no-cementing")) {
4818 cement_enabled = FALSE;
4822 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4825 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4828 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4833 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4834 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4835 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4836 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4837 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4838 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4839 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4840 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4841 fprintf (stderr, " [no-]cementing\n");
4842 if (major_collector.is_concurrent)
4843 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4844 if (major_collector.print_gc_param_usage)
4845 major_collector.print_gc_param_usage ();
4846 if (sgen_minor_collector.print_gc_param_usage)
4847 sgen_minor_collector.print_gc_param_usage ();
4848 fprintf (stderr, " Experimental options:\n");
4849 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4850 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);
4851 fprintf (stderr, "\n");
4853 usage_printed = TRUE;
4858 if (major_collector.is_concurrent)
4859 sgen_workers_init (1);
4861 if (major_collector_opt)
4862 g_free (major_collector_opt);
4864 if (minor_collector_opt)
4865 g_free (minor_collector_opt);
4869 if (major_collector.is_concurrent && cement_enabled) {
4870 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported on concurrent major collectors.");
4871 cement_enabled = FALSE;
4874 sgen_cement_init (cement_enabled);
4876 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4877 gboolean usage_printed = FALSE;
4879 opts = g_strsplit (env, ",", -1);
4880 for (ptr = opts; ptr && *ptr; ptr ++) {
4882 if (!strcmp (opt, ""))
4884 if (opt [0] >= '0' && opt [0] <= '9') {
4885 gc_debug_level = atoi (opt);
4890 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4891 gc_debug_file = fopen (rf, "wb");
4893 gc_debug_file = stderr;
4896 } else if (!strcmp (opt, "print-allowance")) {
4897 debug_print_allowance = TRUE;
4898 } else if (!strcmp (opt, "print-pinning")) {
4899 do_pin_stats = TRUE;
4900 } else if (!strcmp (opt, "verify-before-allocs")) {
4901 verify_before_allocs = 1;
4902 has_per_allocation_action = TRUE;
4903 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4904 char *arg = strchr (opt, '=') + 1;
4905 verify_before_allocs = atoi (arg);
4906 has_per_allocation_action = TRUE;
4907 } else if (!strcmp (opt, "collect-before-allocs")) {
4908 collect_before_allocs = 1;
4909 has_per_allocation_action = TRUE;
4910 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4911 char *arg = strchr (opt, '=') + 1;
4912 has_per_allocation_action = TRUE;
4913 collect_before_allocs = atoi (arg);
4914 } else if (!strcmp (opt, "verify-before-collections")) {
4915 whole_heap_check_before_collection = TRUE;
4916 } else if (!strcmp (opt, "check-at-minor-collections")) {
4917 consistency_check_at_minor_collection = TRUE;
4918 nursery_clear_policy = CLEAR_AT_GC;
4919 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4920 if (!major_collector.is_concurrent) {
4921 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4924 mod_union_consistency_check = TRUE;
4925 } else if (!strcmp (opt, "check-mark-bits")) {
4926 check_mark_bits_after_major_collection = TRUE;
4927 } else if (!strcmp (opt, "check-nursery-pinned")) {
4928 check_nursery_objects_pinned = TRUE;
4929 } else if (!strcmp (opt, "xdomain-checks")) {
4930 xdomain_checks = TRUE;
4931 } else if (!strcmp (opt, "clear-at-gc")) {
4932 nursery_clear_policy = CLEAR_AT_GC;
4933 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4934 nursery_clear_policy = CLEAR_AT_GC;
4935 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4936 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4937 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4938 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4939 } else if (!strcmp (opt, "check-scan-starts")) {
4940 do_scan_starts_check = TRUE;
4941 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4942 do_verify_nursery = TRUE;
4943 } else if (!strcmp (opt, "check-concurrent")) {
4944 if (!major_collector.is_concurrent) {
4945 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4948 do_concurrent_checks = TRUE;
4949 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4950 do_dump_nursery_content = TRUE;
4951 } else if (!strcmp (opt, "no-managed-allocator")) {
4952 sgen_set_use_managed_allocator (FALSE);
4953 } else if (!strcmp (opt, "disable-minor")) {
4954 disable_minor_collections = TRUE;
4955 } else if (!strcmp (opt, "disable-major")) {
4956 disable_major_collections = TRUE;
4957 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4958 char *filename = strchr (opt, '=') + 1;
4959 nursery_clear_policy = CLEAR_AT_GC;
4960 heap_dump_file = fopen (filename, "w");
4961 if (heap_dump_file) {
4962 fprintf (heap_dump_file, "<sgen-dump>\n");
4963 do_pin_stats = TRUE;
4965 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4966 char *filename = strchr (opt, '=') + 1;
4967 char *colon = strrchr (filename, ':');
4970 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
4971 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
4976 binary_protocol_init (filename, (long long)limit);
4977 } else if (!strcmp (opt, "nursery-canaries")) {
4978 do_verify_nursery = TRUE;
4979 sgen_set_use_managed_allocator (FALSE);
4980 enable_nursery_canaries = TRUE;
4981 } else if (!strcmp (opt, "do-not-finalize")) {
4982 do_not_finalize = TRUE;
4983 } else if (!strcmp (opt, "log-finalizers")) {
4984 log_finalizers = TRUE;
4985 } else if (!sgen_bridge_handle_gc_debug (opt)) {
4986 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4991 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);
4992 fprintf (stderr, "Valid <option>s are:\n");
4993 fprintf (stderr, " collect-before-allocs[=<n>]\n");
4994 fprintf (stderr, " verify-before-allocs[=<n>]\n");
4995 fprintf (stderr, " check-at-minor-collections\n");
4996 fprintf (stderr, " check-mark-bits\n");
4997 fprintf (stderr, " check-nursery-pinned\n");
4998 fprintf (stderr, " verify-before-collections\n");
4999 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5000 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5001 fprintf (stderr, " disable-minor\n");
5002 fprintf (stderr, " disable-major\n");
5003 fprintf (stderr, " xdomain-checks\n");
5004 fprintf (stderr, " check-concurrent\n");
5005 fprintf (stderr, " clear-[nursery-]at-gc\n");
5006 fprintf (stderr, " clear-at-tlab-creation\n");
5007 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5008 fprintf (stderr, " check-scan-starts\n");
5009 fprintf (stderr, " no-managed-allocator\n");
5010 fprintf (stderr, " print-allowance\n");
5011 fprintf (stderr, " print-pinning\n");
5012 fprintf (stderr, " heap-dump=<filename>\n");
5013 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5014 fprintf (stderr, " nursery-canaries\n");
5015 fprintf (stderr, " do-not-finalize\n");
5016 fprintf (stderr, " log-finalizers\n");
5017 sgen_bridge_print_gc_debug_usage ();
5018 fprintf (stderr, "\n");
5020 usage_printed = TRUE;
5026 if (check_mark_bits_after_major_collection)
5027 nursery_clear_policy = CLEAR_AT_GC;
5029 if (major_collector.post_param_init)
5030 major_collector.post_param_init (&major_collector);
5032 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5034 memset (&remset, 0, sizeof (remset));
5036 sgen_card_table_init (&remset);
5042 mono_gc_get_gc_name (void)
5047 static MonoMethod *write_barrier_conc_method;
5048 static MonoMethod *write_barrier_noconc_method;
5051 sgen_is_critical_method (MonoMethod *method)
5053 return (method == write_barrier_conc_method || method == write_barrier_noconc_method || sgen_is_managed_allocator (method));
5057 sgen_has_critical_method (void)
5059 return write_barrier_conc_method || write_barrier_noconc_method || sgen_has_managed_allocator ();
5065 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels, gboolean is_concurrent)
5067 int shifted_nursery_start = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5069 memset (nursery_check_return_labels, 0, sizeof (int) * 2);
5070 // if (ptr_in_nursery (ptr)) return;
5072 * Masking out the bits might be faster, but we would have to use 64 bit
5073 * immediates, which might be slower.
5075 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
5076 mono_mb_emit_byte (mb, CEE_MONO_LDPTR_NURSERY_START);
5077 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5078 mono_mb_emit_byte (mb, CEE_SHR_UN);
5079 mono_mb_emit_stloc (mb, shifted_nursery_start);
5081 mono_mb_emit_ldarg (mb, 0);
5082 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5083 mono_mb_emit_byte (mb, CEE_SHR_UN);
5084 mono_mb_emit_ldloc (mb, shifted_nursery_start);
5085 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5087 if (!is_concurrent) {
5088 // if (!ptr_in_nursery (*ptr)) return;
5089 mono_mb_emit_ldarg (mb, 0);
5090 mono_mb_emit_byte (mb, CEE_LDIND_I);
5091 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5092 mono_mb_emit_byte (mb, CEE_SHR_UN);
5093 mono_mb_emit_ldloc (mb, shifted_nursery_start);
5094 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5100 mono_gc_get_specific_write_barrier (gboolean is_concurrent)
5103 MonoMethodBuilder *mb;
5104 MonoMethodSignature *sig;
5105 MonoMethod **write_barrier_method_addr;
5106 #ifdef MANAGED_WBARRIER
5107 int i, nursery_check_labels [2];
5109 #ifdef HAVE_KW_THREAD
5110 int stack_end_offset = -1;
5112 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5113 g_assert (stack_end_offset != -1);
5117 // FIXME: Maybe create a separate version for ctors (the branch would be
5118 // correctly predicted more times)
5120 write_barrier_method_addr = &write_barrier_conc_method;
5122 write_barrier_method_addr = &write_barrier_noconc_method;
5124 if (*write_barrier_method_addr)
5125 return *write_barrier_method_addr;
5127 /* Create the IL version of mono_gc_barrier_generic_store () */
5128 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5129 sig->ret = &mono_defaults.void_class->byval_arg;
5130 sig->params [0] = &mono_defaults.int_class->byval_arg;
5133 mb = mono_mb_new (mono_defaults.object_class, "wbarrier_conc", MONO_WRAPPER_WRITE_BARRIER);
5135 mb = mono_mb_new (mono_defaults.object_class, "wbarrier_noconc", MONO_WRAPPER_WRITE_BARRIER);
5138 #ifdef MANAGED_WBARRIER
5139 emit_nursery_check (mb, nursery_check_labels, is_concurrent);
5141 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5145 LDC_PTR sgen_cardtable
5147 address >> CARD_BITS
5151 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5152 LDC_PTR card_table_mask
5159 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
5160 mono_mb_emit_byte (mb, CEE_MONO_LDPTR_CARD_TABLE);
5161 mono_mb_emit_ldarg (mb, 0);
5162 mono_mb_emit_icon (mb, CARD_BITS);
5163 mono_mb_emit_byte (mb, CEE_SHR_UN);
5164 mono_mb_emit_byte (mb, CEE_CONV_I);
5165 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5166 #if SIZEOF_VOID_P == 8
5167 mono_mb_emit_icon8 (mb, CARD_MASK);
5169 mono_mb_emit_icon (mb, CARD_MASK);
5171 mono_mb_emit_byte (mb, CEE_CONV_I);
5172 mono_mb_emit_byte (mb, CEE_AND);
5174 mono_mb_emit_byte (mb, CEE_ADD);
5175 mono_mb_emit_icon (mb, 1);
5176 mono_mb_emit_byte (mb, CEE_STIND_I1);
5179 for (i = 0; i < 2; ++i) {
5180 if (nursery_check_labels [i])
5181 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5183 mono_mb_emit_byte (mb, CEE_RET);
5185 mono_mb_emit_ldarg (mb, 0);
5186 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5187 mono_mb_emit_byte (mb, CEE_RET);
5190 res = mono_mb_create_method (mb, sig, 16);
5194 if (*write_barrier_method_addr) {
5195 /* Already created */
5196 mono_free_method (res);
5198 /* double-checked locking */
5199 mono_memory_barrier ();
5200 *write_barrier_method_addr = res;
5204 return *write_barrier_method_addr;
5208 mono_gc_get_write_barrier (void)
5210 return mono_gc_get_specific_write_barrier (major_collector.is_concurrent);
5214 mono_gc_get_description (void)
5216 return g_strdup ("sgen");
5220 mono_gc_set_desktop_mode (void)
5225 mono_gc_is_moving (void)
5231 mono_gc_is_disabled (void)
5237 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5244 sgen_get_nursery_clear_policy (void)
5246 return nursery_clear_policy;
5250 sgen_get_array_fill_vtable (void)
5252 if (!array_fill_vtable) {
5253 static MonoClass klass;
5254 static char _vtable[sizeof(MonoVTable)+8];
5255 MonoVTable* vtable = (MonoVTable*) ALIGN_TO(_vtable, 8);
5258 MonoDomain *domain = mono_get_root_domain ();
5261 klass.element_class = mono_defaults.byte_class;
5263 klass.instance_size = sizeof (MonoArray);
5264 klass.sizes.element_size = 1;
5265 klass.name = "array_filler_type";
5267 vtable->klass = &klass;
5269 vtable->gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5272 array_fill_vtable = vtable;
5274 return array_fill_vtable;
5284 sgen_gc_unlock (void)
5286 gboolean try_free = sgen_try_free_some_memory;
5287 sgen_try_free_some_memory = FALSE;
5288 mono_mutex_unlock (&gc_mutex);
5289 MONO_GC_UNLOCKED ();
5291 mono_thread_hazardous_try_free_some ();
5295 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5297 major_collector.iterate_live_block_ranges (callback);
5301 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5303 major_collector.scan_card_table (FALSE, queue);
5307 sgen_get_major_collector (void)
5309 return &major_collector;
5312 void mono_gc_set_skip_thread (gboolean skip)
5314 SgenThreadInfo *info = mono_thread_info_current ();
5317 info->gc_disabled = skip;
5322 sgen_get_remset (void)
5328 mono_gc_get_vtable_bits (MonoClass *class)
5331 /* FIXME move this to the bridge code */
5332 if (sgen_need_bridge_processing ()) {
5333 switch (sgen_bridge_class_kind (class)) {
5334 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5335 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5336 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5338 case GC_BRIDGE_OPAQUE_CLASS:
5339 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5341 case GC_BRIDGE_TRANSPARENT_CLASS:
5345 if (fin_callbacks.is_class_finalization_aware) {
5346 if (fin_callbacks.is_class_finalization_aware (class))
5347 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5353 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5360 sgen_check_whole_heap_stw (void)
5362 sgen_stop_world (0);
5363 sgen_clear_nursery_fragments ();
5364 sgen_check_whole_heap (FALSE);
5365 sgen_restart_world (0, NULL);
5369 sgen_gc_event_moves (void)
5371 if (moved_objects_idx) {
5372 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5373 moved_objects_idx = 0;
5378 sgen_timestamp (void)
5380 SGEN_TV_DECLARE (timestamp);
5381 SGEN_TV_GETTIME (timestamp);
5382 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5386 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5388 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5389 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5391 fin_callbacks = *callbacks;
5398 #endif /* HAVE_SGEN_GC */