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;
1092 sgen_pin_object (void *object, GrayQueue *queue)
1094 SGEN_PIN_OBJECT (object);
1095 sgen_pin_stage_ptr (object);
1097 if (G_UNLIKELY (do_pin_stats))
1098 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1100 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1101 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1103 #ifdef ENABLE_DTRACE
1104 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1105 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1106 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1107 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1113 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1117 gboolean major_pinned = FALSE;
1119 if (sgen_ptr_in_nursery (obj)) {
1120 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1121 sgen_pin_object (obj, queue);
1125 major_collector.pin_major_object (obj, queue);
1126 major_pinned = TRUE;
1129 vtable_word = *(mword*)obj;
1130 /*someone else forwarded it, update the pointer and bail out*/
1131 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1132 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1136 /*someone pinned it, nothing to do.*/
1137 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1142 /* Sort the addresses in array in increasing order.
1143 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1146 sgen_sort_addresses (void **array, size_t size)
1151 for (i = 1; i < size; ++i) {
1154 size_t parent = (child - 1) / 2;
1156 if (array [parent] >= array [child])
1159 tmp = array [parent];
1160 array [parent] = array [child];
1161 array [child] = tmp;
1167 for (i = size - 1; i > 0; --i) {
1170 array [i] = array [0];
1176 while (root * 2 + 1 <= end) {
1177 size_t child = root * 2 + 1;
1179 if (child < end && array [child] < array [child + 1])
1181 if (array [root] >= array [child])
1185 array [root] = array [child];
1186 array [child] = tmp;
1194 * Scan the memory between start and end and queue values which could be pointers
1195 * to the area between start_nursery and end_nursery for later consideration.
1196 * Typically used for thread stacks.
1199 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1203 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1204 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1207 while (start < end) {
1208 if (*start >= start_nursery && *start < end_nursery) {
1210 * *start can point to the middle of an object
1211 * note: should we handle pointing at the end of an object?
1212 * pinning in C# code disallows pointing at the end of an object
1213 * but there is some small chance that an optimizing C compiler
1214 * may keep the only reference to an object by pointing
1215 * at the end of it. We ignore this small chance for now.
1216 * Pointers to the end of an object are indistinguishable
1217 * from pointers to the start of the next object in memory
1218 * so if we allow that we'd need to pin two objects...
1219 * We queue the pointer in an array, the
1220 * array will then be sorted and uniqued. This way
1221 * we can coalesce several pinning pointers and it should
1222 * be faster since we'd do a memory scan with increasing
1223 * addresses. Note: we can align the address to the allocation
1224 * alignment, so the unique process is more effective.
1226 mword addr = (mword)*start;
1227 addr &= ~(ALLOC_ALIGN - 1);
1228 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1229 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1230 sgen_pin_stage_ptr ((void*)addr);
1231 binary_protocol_pin_stage (start, (void*)addr);
1234 if (G_UNLIKELY (do_pin_stats)) {
1235 if (ptr_in_nursery ((void*)addr))
1236 sgen_pin_stats_register_address ((char*)addr, pin_type);
1242 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1246 * The first thing we do in a collection is to identify pinned objects.
1247 * This function considers all the areas of memory that need to be
1248 * conservatively scanned.
1251 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1255 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);
1256 /* objects pinned from the API are inside these roots */
1257 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1258 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1259 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1260 } SGEN_HASH_TABLE_FOREACH_END;
1261 /* now deal with the thread stacks
1262 * in the future we should be able to conservatively scan only:
1263 * *) the cpu registers
1264 * *) the unmanaged stack frames
1265 * *) the _last_ managed stack frame
1266 * *) pointers slots in managed frames
1268 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1272 unpin_objects_from_queue (SgenGrayQueue *queue)
1277 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1280 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1281 SGEN_UNPIN_OBJECT (addr);
1286 CopyOrMarkObjectFunc func;
1288 } UserCopyOrMarkData;
1291 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1293 UserCopyOrMarkData *data = gc_data;
1295 data->func (obj, data->queue);
1299 * The memory area from start_root to end_root contains pointers to objects.
1300 * Their position is precisely described by @desc (this means that the pointer
1301 * can be either NULL or the pointer to the start of an object).
1302 * This functions copies them to to_space updates them.
1304 * This function is not thread-safe!
1307 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1309 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1310 SgenGrayQueue *queue = ctx.queue;
1312 switch (desc & ROOT_DESC_TYPE_MASK) {
1313 case ROOT_DESC_BITMAP:
1314 desc >>= ROOT_DESC_TYPE_SHIFT;
1316 if ((desc & 1) && *start_root) {
1317 copy_func (start_root, queue);
1318 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1324 case ROOT_DESC_COMPLEX: {
1325 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1326 gsize bwords = (*bitmap_data) - 1;
1327 void **start_run = start_root;
1329 while (bwords-- > 0) {
1330 gsize bmap = *bitmap_data++;
1331 void **objptr = start_run;
1333 if ((bmap & 1) && *objptr) {
1334 copy_func (objptr, queue);
1335 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1340 start_run += GC_BITS_PER_WORD;
1344 case ROOT_DESC_USER: {
1345 UserCopyOrMarkData data = { copy_func, queue };
1346 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1347 marker (start_root, single_arg_user_copy_or_mark, &data);
1350 case ROOT_DESC_RUN_LEN:
1351 g_assert_not_reached ();
1353 g_assert_not_reached ();
1358 reset_heap_boundaries (void)
1360 lowest_heap_address = ~(mword)0;
1361 highest_heap_address = 0;
1365 sgen_update_heap_boundaries (mword low, mword high)
1370 old = lowest_heap_address;
1373 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1376 old = highest_heap_address;
1379 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1383 * Allocate and setup the data structures needed to be able to allocate objects
1384 * in the nursery. The nursery is stored in nursery_section.
1387 alloc_nursery (void)
1389 GCMemSection *section;
1394 if (nursery_section)
1396 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1397 /* later we will alloc a larger area for the nursery but only activate
1398 * what we need. The rest will be used as expansion if we have too many pinned
1399 * objects in the existing nursery.
1401 /* FIXME: handle OOM */
1402 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1404 alloc_size = sgen_nursery_size;
1406 /* If there isn't enough space even for the nursery we should simply abort. */
1407 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1409 #ifdef SGEN_ALIGN_NURSERY
1410 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1412 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1414 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1415 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 ());
1416 section->data = section->next_data = data;
1417 section->size = alloc_size;
1418 section->end_data = data + sgen_nursery_size;
1419 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1420 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1421 section->num_scan_start = scan_starts;
1423 nursery_section = section;
1425 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1429 mono_gc_get_nursery (int *shift_bits, size_t *size)
1431 *size = sgen_nursery_size;
1432 #ifdef SGEN_ALIGN_NURSERY
1433 *shift_bits = DEFAULT_NURSERY_BITS;
1437 return sgen_get_nursery_start ();
1441 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1443 SgenThreadInfo *info = mono_thread_info_current ();
1445 /* Could be called from sgen_thread_unregister () with a NULL info */
1448 info->stopped_domain = domain;
1453 mono_gc_precise_stack_mark_enabled (void)
1455 return !conservative_stack_mark;
1459 mono_gc_get_logfile (void)
1461 return gc_debug_file;
1465 report_finalizer_roots_list (FinalizeReadyEntry *list)
1467 GCRootReport report;
1468 FinalizeReadyEntry *fin;
1471 for (fin = list; fin; fin = fin->next) {
1474 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1476 notify_gc_roots (&report);
1480 report_finalizer_roots (void)
1482 report_finalizer_roots_list (fin_ready_list);
1483 report_finalizer_roots_list (critical_fin_list);
1486 static GCRootReport *root_report;
1489 single_arg_report_root (void **obj, void *gc_data)
1492 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1496 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1498 switch (desc & ROOT_DESC_TYPE_MASK) {
1499 case ROOT_DESC_BITMAP:
1500 desc >>= ROOT_DESC_TYPE_SHIFT;
1502 if ((desc & 1) && *start_root) {
1503 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1509 case ROOT_DESC_COMPLEX: {
1510 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1511 gsize bwords = (*bitmap_data) - 1;
1512 void **start_run = start_root;
1514 while (bwords-- > 0) {
1515 gsize bmap = *bitmap_data++;
1516 void **objptr = start_run;
1518 if ((bmap & 1) && *objptr) {
1519 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1524 start_run += GC_BITS_PER_WORD;
1528 case ROOT_DESC_USER: {
1529 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1530 root_report = report;
1531 marker (start_root, single_arg_report_root, NULL);
1534 case ROOT_DESC_RUN_LEN:
1535 g_assert_not_reached ();
1537 g_assert_not_reached ();
1542 report_registered_roots_by_type (int root_type)
1544 GCRootReport report;
1548 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1549 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1550 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1551 } SGEN_HASH_TABLE_FOREACH_END;
1552 notify_gc_roots (&report);
1556 report_registered_roots (void)
1558 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1559 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1563 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1565 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1566 SgenGrayQueue *queue = ctx.queue;
1567 FinalizeReadyEntry *fin;
1569 for (fin = list; fin; fin = fin->next) {
1572 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1573 copy_func (&fin->object, queue);
1578 generation_name (int generation)
1580 switch (generation) {
1581 case GENERATION_NURSERY: return "nursery";
1582 case GENERATION_OLD: return "old";
1583 default: g_assert_not_reached ();
1588 sgen_generation_name (int generation)
1590 return generation_name (generation);
1593 SgenObjectOperations *
1594 sgen_get_current_object_ops (void){
1595 return ¤t_object_ops;
1600 finish_gray_stack (int generation, GrayQueue *queue)
1604 int done_with_ephemerons, ephemeron_rounds = 0;
1605 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1606 ScanObjectFunc scan_func = current_object_ops.scan_object;
1607 ScanCopyContext ctx = { scan_func, copy_func, queue };
1608 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1609 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1612 * We copied all the reachable objects. Now it's the time to copy
1613 * the objects that were not referenced by the roots, but by the copied objects.
1614 * we built a stack of objects pointed to by gray_start: they are
1615 * additional roots and we may add more items as we go.
1616 * We loop until gray_start == gray_objects which means no more objects have
1617 * been added. Note this is iterative: no recursion is involved.
1618 * We need to walk the LO list as well in search of marked big objects
1619 * (use a flag since this is needed only on major collections). We need to loop
1620 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1621 * To achieve better cache locality and cache usage, we drain the gray stack
1622 * frequently, after each object is copied, and just finish the work here.
1624 sgen_drain_gray_stack (-1, ctx);
1626 SGEN_LOG (2, "%s generation done", generation_name (generation));
1629 Reset bridge data, we might have lingering data from a previous collection if this is a major
1630 collection trigged by minor overflow.
1632 We must reset the gathered bridges since their original block might be evacuated due to major
1633 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1635 if (sgen_need_bridge_processing ())
1636 sgen_bridge_reset_data ();
1639 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1640 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1641 * objects that are in fact reachable.
1643 done_with_ephemerons = 0;
1645 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1646 sgen_drain_gray_stack (-1, ctx);
1648 } while (!done_with_ephemerons);
1650 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1652 if (sgen_need_bridge_processing ()) {
1653 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1654 sgen_drain_gray_stack (-1, ctx);
1655 sgen_collect_bridge_objects (generation, ctx);
1656 if (generation == GENERATION_OLD)
1657 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1660 Do the first bridge step here, as the collector liveness state will become useless after that.
1662 An important optimization is to only proccess the possibly dead part of the object graph and skip
1663 over all live objects as we transitively know everything they point must be alive too.
1665 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1667 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1668 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1671 sgen_bridge_processing_stw_step ();
1675 Make sure we drain the gray stack before processing disappearing links and finalizers.
1676 If we don't make sure it is empty we might wrongly see a live object as dead.
1678 sgen_drain_gray_stack (-1, ctx);
1681 We must clear weak links that don't track resurrection before processing object ready for
1682 finalization so they can be cleared before that.
1684 sgen_null_link_in_range (generation, TRUE, ctx);
1685 if (generation == GENERATION_OLD)
1686 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1689 /* walk the finalization queue and move also the objects that need to be
1690 * finalized: use the finalized objects as new roots so the objects they depend
1691 * on are also not reclaimed. As with the roots above, only objects in the nursery
1692 * are marked/copied.
1694 sgen_finalize_in_range (generation, ctx);
1695 if (generation == GENERATION_OLD)
1696 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1697 /* drain the new stack that might have been created */
1698 SGEN_LOG (6, "Precise scan of gray area post fin");
1699 sgen_drain_gray_stack (-1, ctx);
1702 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1704 done_with_ephemerons = 0;
1706 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1707 sgen_drain_gray_stack (-1, ctx);
1709 } while (!done_with_ephemerons);
1712 * Clear ephemeron pairs with unreachable keys.
1713 * We pass the copy func so we can figure out if an array was promoted or not.
1715 clear_unreachable_ephemerons (ctx);
1718 * We clear togglerefs only after all possible chances of revival are done.
1719 * This is semantically more inline with what users expect and it allows for
1720 * user finalizers to correctly interact with TR objects.
1722 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1725 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1728 * handle disappearing links
1729 * Note we do this after checking the finalization queue because if an object
1730 * survives (at least long enough to be finalized) we don't clear the link.
1731 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1732 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1735 g_assert (sgen_gray_object_queue_is_empty (queue));
1737 sgen_null_link_in_range (generation, FALSE, ctx);
1738 if (generation == GENERATION_OLD)
1739 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1740 if (sgen_gray_object_queue_is_empty (queue))
1742 sgen_drain_gray_stack (-1, ctx);
1745 g_assert (sgen_gray_object_queue_is_empty (queue));
1747 sgen_gray_object_queue_trim_free_list (queue);
1751 sgen_check_section_scan_starts (GCMemSection *section)
1754 for (i = 0; i < section->num_scan_start; ++i) {
1755 if (section->scan_starts [i]) {
1756 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1757 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1763 check_scan_starts (void)
1765 if (!do_scan_starts_check)
1767 sgen_check_section_scan_starts (nursery_section);
1768 major_collector.check_scan_starts ();
1772 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1776 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1777 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1778 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1779 } SGEN_HASH_TABLE_FOREACH_END;
1783 sgen_dump_occupied (char *start, char *end, char *section_start)
1785 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1789 sgen_dump_section (GCMemSection *section, const char *type)
1791 char *start = section->data;
1792 char *end = section->data + section->size;
1793 char *occ_start = NULL;
1795 char *old_start G_GNUC_UNUSED = NULL; /* just for debugging */
1797 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1799 while (start < end) {
1801 MonoClass *class G_GNUC_UNUSED;
1803 if (!*(void**)start) {
1805 sgen_dump_occupied (occ_start, start, section->data);
1808 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1811 g_assert (start < section->next_data);
1816 vt = (GCVTable*)LOAD_VTABLE (start);
1819 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1822 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1823 start - section->data,
1824 vt->klass->name_space, vt->klass->name,
1832 sgen_dump_occupied (occ_start, start, section->data);
1834 fprintf (heap_dump_file, "</section>\n");
1838 dump_object (MonoObject *obj, gboolean dump_location)
1840 static char class_name [1024];
1842 MonoClass *class = mono_object_class (obj);
1846 * Python's XML parser is too stupid to parse angle brackets
1847 * in strings, so we just ignore them;
1850 while (class->name [i] && j < sizeof (class_name) - 1) {
1851 if (!strchr ("<>\"", class->name [i]))
1852 class_name [j++] = class->name [i];
1855 g_assert (j < sizeof (class_name));
1858 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1859 class->name_space, class_name,
1860 safe_object_get_size (obj));
1861 if (dump_location) {
1862 const char *location;
1863 if (ptr_in_nursery (obj))
1864 location = "nursery";
1865 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1869 fprintf (heap_dump_file, " location=\"%s\"", location);
1871 fprintf (heap_dump_file, "/>\n");
1875 dump_heap (const char *type, int num, const char *reason)
1880 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1882 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1883 fprintf (heap_dump_file, ">\n");
1884 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1885 sgen_dump_internal_mem_usage (heap_dump_file);
1886 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1887 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1888 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1890 fprintf (heap_dump_file, "<pinned-objects>\n");
1891 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1892 dump_object (list->obj, TRUE);
1893 fprintf (heap_dump_file, "</pinned-objects>\n");
1895 sgen_dump_section (nursery_section, "nursery");
1897 major_collector.dump_heap (heap_dump_file);
1899 fprintf (heap_dump_file, "<los>\n");
1900 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1901 dump_object ((MonoObject*)bigobj->data, FALSE);
1902 fprintf (heap_dump_file, "</los>\n");
1904 fprintf (heap_dump_file, "</collection>\n");
1908 sgen_register_moved_object (void *obj, void *destination)
1910 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1912 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1913 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1914 moved_objects_idx = 0;
1916 moved_objects [moved_objects_idx++] = obj;
1917 moved_objects [moved_objects_idx++] = destination;
1923 static gboolean inited = FALSE;
1928 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1930 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1931 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1932 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1933 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1934 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1935 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1936 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1937 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1939 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1940 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1941 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1942 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1943 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1944 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1945 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1946 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1947 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1948 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1949 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1950 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1951 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1953 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1955 #ifdef HEAVY_STATISTICS
1956 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1957 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1958 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1959 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1960 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1961 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1962 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1963 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1964 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1966 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1967 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1969 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1970 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1971 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1972 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1974 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1975 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1977 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1979 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1980 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1981 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1982 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1984 sgen_nursery_allocator_init_heavy_stats ();
1985 sgen_alloc_init_heavy_stats ();
1993 reset_pinned_from_failed_allocation (void)
1995 bytes_pinned_from_failed_allocation = 0;
1999 sgen_set_pinned_from_failed_allocation (mword objsize)
2001 bytes_pinned_from_failed_allocation += objsize;
2005 sgen_collection_is_concurrent (void)
2007 switch (current_collection_generation) {
2008 case GENERATION_NURSERY:
2010 case GENERATION_OLD:
2011 return concurrent_collection_in_progress;
2013 g_error ("Invalid current generation %d", current_collection_generation);
2018 sgen_concurrent_collection_in_progress (void)
2020 return concurrent_collection_in_progress;
2024 job_remembered_set_scan (WorkerData *worker_data, void *dummy)
2026 remset.scan_remsets (sgen_workers_get_job_gray_queue (worker_data));
2031 CopyOrMarkObjectFunc copy_or_mark_func;
2032 ScanObjectFunc scan_func;
2036 } ScanFromRegisteredRootsJobData;
2039 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2041 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2042 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2043 sgen_workers_get_job_gray_queue (worker_data) };
2045 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2046 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2053 } ScanThreadDataJobData;
2056 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2058 ScanThreadDataJobData *job_data = job_data_untyped;
2060 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2061 sgen_workers_get_job_gray_queue (worker_data));
2062 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2066 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2068 FinalizeReadyEntry *list = job_data_untyped;
2069 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2071 scan_finalizer_entries (list, ctx);
2075 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2077 g_assert (concurrent_collection_in_progress);
2078 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2082 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2084 g_assert (concurrent_collection_in_progress);
2085 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2089 verify_scan_starts (char *start, char *end)
2093 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2094 char *addr = nursery_section->scan_starts [i];
2095 if (addr > start && addr < end)
2096 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2101 verify_nursery (void)
2103 char *start, *end, *cur, *hole_start;
2105 if (!do_verify_nursery)
2108 if (nursery_canaries_enabled ())
2109 SGEN_LOG (1, "Checking nursery canaries...");
2111 /*This cleans up unused fragments */
2112 sgen_nursery_allocator_prepare_for_pinning ();
2114 hole_start = start = cur = sgen_get_nursery_start ();
2115 end = sgen_get_nursery_end ();
2120 if (!*(void**)cur) {
2121 cur += sizeof (void*);
2125 if (object_is_forwarded (cur))
2126 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2127 else if (object_is_pinned (cur))
2128 SGEN_LOG (1, "PINNED OBJ %p", cur);
2130 ss = safe_object_get_size ((MonoObject*)cur);
2131 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2132 verify_scan_starts (cur, cur + size);
2133 if (do_dump_nursery_content) {
2134 if (cur > hole_start)
2135 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2136 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 ());
2138 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2139 CHECK_CANARY_FOR_OBJECT (cur);
2140 CANARIFY_SIZE (size);
2148 * Checks that no objects in the nursery are fowarded or pinned. This
2149 * is a precondition to restarting the mutator while doing a
2150 * concurrent collection. Note that we don't clear fragments because
2151 * we depend on that having happened earlier.
2154 check_nursery_is_clean (void)
2158 cur = sgen_get_nursery_start ();
2159 end = sgen_get_nursery_end ();
2164 if (!*(void**)cur) {
2165 cur += sizeof (void*);
2169 g_assert (!object_is_forwarded (cur));
2170 g_assert (!object_is_pinned (cur));
2172 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2173 verify_scan_starts (cur, cur + size);
2180 init_gray_queue (void)
2182 if (sgen_collection_is_concurrent ())
2183 sgen_workers_init_distribute_gray_queue ();
2184 sgen_gray_object_queue_init (&gray_queue, NULL);
2188 * Perform a nursery collection.
2190 * Return whether any objects were late-pinned due to being out of memory.
2193 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2195 gboolean needs_major;
2196 size_t max_garbage_amount;
2198 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2199 ScanThreadDataJobData *stdjd;
2200 mword fragment_total;
2201 ScanCopyContext ctx;
2205 if (disable_minor_collections)
2208 TV_GETTIME (last_minor_collection_start_tv);
2209 atv = last_minor_collection_start_tv;
2211 MONO_GC_BEGIN (GENERATION_NURSERY);
2212 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2216 #ifndef DISABLE_PERFCOUNTERS
2217 mono_perfcounters->gc_collections0++;
2220 current_collection_generation = GENERATION_NURSERY;
2221 current_object_ops = sgen_minor_collector.serial_ops;
2223 reset_pinned_from_failed_allocation ();
2225 check_scan_starts ();
2227 sgen_nursery_alloc_prepare_for_minor ();
2231 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2232 /* FIXME: optimize later to use the higher address where an object can be present */
2233 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2235 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 ()));
2236 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2237 g_assert (nursery_section->size >= max_garbage_amount);
2239 /* world must be stopped already */
2241 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2243 if (xdomain_checks) {
2244 sgen_clear_nursery_fragments ();
2245 sgen_check_for_xdomain_refs ();
2248 nursery_section->next_data = nursery_next;
2250 major_collector.start_nursery_collection ();
2252 sgen_memgov_minor_collection_start ();
2256 gc_stats.minor_gc_count ++;
2258 if (whole_heap_check_before_collection) {
2259 sgen_clear_nursery_fragments ();
2260 sgen_check_whole_heap (finish_up_concurrent_mark);
2262 if (consistency_check_at_minor_collection)
2263 sgen_check_consistency ();
2265 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2267 sgen_process_fin_stage_entries ();
2268 sgen_process_dislink_stage_entries ();
2270 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2272 /* pin from pinned handles */
2273 sgen_init_pinning ();
2274 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2275 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2276 /* pin cemented objects */
2277 sgen_pin_cemented_objects ();
2278 /* identify pinned objects */
2279 sgen_optimize_pin_queue ();
2280 sgen_pinning_setup_section (nursery_section);
2281 ctx.scan_func = NULL;
2282 ctx.copy_func = NULL;
2283 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2284 pin_objects_in_nursery (ctx);
2285 sgen_pinning_trim_queue_to_section (nursery_section);
2288 time_minor_pinning += TV_ELAPSED (btv, atv);
2289 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2290 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2292 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2295 * FIXME: When we finish a concurrent collection we do a nursery collection first,
2296 * as part of which we scan the card table. Then, later, we scan the mod union
2297 * cardtable. We should only have to do one.
2299 sgen_workers_enqueue_job (job_remembered_set_scan, NULL);
2301 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2303 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2304 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2306 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2308 /* FIXME: why is this here? */
2309 ctx.scan_func = current_object_ops.scan_object;
2310 ctx.copy_func = NULL;
2311 ctx.queue = &gray_queue;
2312 sgen_drain_gray_stack (-1, ctx);
2314 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2315 report_registered_roots ();
2316 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2317 report_finalizer_roots ();
2319 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2321 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2323 /* registered roots, this includes static fields */
2324 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2325 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2326 scrrjd_normal->scan_func = current_object_ops.scan_object;
2327 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2328 scrrjd_normal->heap_end = nursery_next;
2329 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2330 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2332 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2333 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2334 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2335 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2336 scrrjd_wbarrier->heap_end = nursery_next;
2337 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2338 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2341 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2343 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2346 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2347 stdjd->heap_start = sgen_get_nursery_start ();
2348 stdjd->heap_end = nursery_next;
2349 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2352 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2355 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2357 g_assert (!sgen_collection_is_concurrent ());
2359 /* Scan the list of objects ready for finalization. If */
2360 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2361 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2363 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2365 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2367 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2368 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2370 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2373 * The (single-threaded) finalization code might have done
2374 * some copying/marking so we can only reset the GC thread's
2375 * worker data here instead of earlier when we joined the
2378 sgen_workers_reset_data ();
2380 if (objects_pinned) {
2381 sgen_optimize_pin_queue ();
2382 sgen_pinning_setup_section (nursery_section);
2385 /* walk the pin_queue, build up the fragment list of free memory, unmark
2386 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2389 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2390 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2391 if (!fragment_total)
2394 /* Clear TLABs for all threads */
2395 sgen_clear_tlabs ();
2397 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2399 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2400 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2402 if (consistency_check_at_minor_collection)
2403 sgen_check_major_refs ();
2405 major_collector.finish_nursery_collection ();
2407 TV_GETTIME (last_minor_collection_end_tv);
2408 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2411 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2413 /* prepare the pin queue for the next collection */
2414 sgen_finish_pinning ();
2415 if (fin_ready_list || critical_fin_list) {
2416 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2417 mono_gc_finalize_notify ();
2419 sgen_pin_stats_reset ();
2420 /* clear cemented hash */
2421 sgen_cement_clear_below_threshold ();
2423 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2425 remset.finish_minor_collection ();
2427 check_scan_starts ();
2429 binary_protocol_flush_buffers (FALSE);
2431 sgen_memgov_minor_collection_end ();
2433 /*objects are late pinned because of lack of memory, so a major is a good call*/
2434 needs_major = objects_pinned > 0;
2435 current_collection_generation = -1;
2438 MONO_GC_END (GENERATION_NURSERY);
2439 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
2441 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2442 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2448 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2451 * This is called on all objects in the nursery, including pinned ones, so we need
2452 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2454 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2458 scan_nursery_objects (ScanCopyContext ctx)
2460 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2461 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2465 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)
2470 /* FIXME: only use these values for the precise scan
2471 * note that to_space pointers should be excluded anyway...
2473 char *heap_start = NULL;
2474 char *heap_end = (char*)-1;
2475 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2476 GCRootReport root_report = { 0 };
2477 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2478 ScanThreadDataJobData *stdjd;
2479 ScanCopyContext ctx;
2481 if (concurrent_collection_in_progress) {
2482 /*This cleans up unused fragments */
2483 sgen_nursery_allocator_prepare_for_pinning ();
2485 if (do_concurrent_checks)
2486 check_nursery_is_clean ();
2488 /* The concurrent collector doesn't touch the nursery. */
2489 sgen_nursery_alloc_prepare_for_major ();
2496 /* Pinning depends on this */
2497 sgen_clear_nursery_fragments ();
2499 if (whole_heap_check_before_collection)
2500 sgen_check_whole_heap (finish_up_concurrent_mark);
2503 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2505 if (!sgen_collection_is_concurrent ())
2506 nursery_section->next_data = sgen_get_nursery_end ();
2507 /* we should also coalesce scanning from sections close to each other
2508 * and deal with pointers outside of the sections later.
2513 if (xdomain_checks) {
2514 sgen_clear_nursery_fragments ();
2515 sgen_check_for_xdomain_refs ();
2518 if (!concurrent_collection_in_progress) {
2519 /* Remsets are not useful for a major collection */
2520 remset.clear_cards ();
2523 sgen_process_fin_stage_entries ();
2524 sgen_process_dislink_stage_entries ();
2527 sgen_init_pinning ();
2528 SGEN_LOG (6, "Collecting pinned addresses");
2529 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2531 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2532 if (major_collector.is_concurrent) {
2534 * The concurrent major collector cannot evict
2535 * yet, so we need to pin cemented objects to
2536 * not break some asserts.
2538 * FIXME: We could evict now!
2540 sgen_pin_cemented_objects ();
2544 sgen_optimize_pin_queue ();
2547 * pin_queue now contains all candidate pointers, sorted and
2548 * uniqued. We must do two passes now to figure out which
2549 * objects are pinned.
2551 * The first is to find within the pin_queue the area for each
2552 * section. This requires that the pin_queue be sorted. We
2553 * also process the LOS objects and pinned chunks here.
2555 * The second, destructive, pass is to reduce the section
2556 * areas to pointers to the actually pinned objects.
2558 SGEN_LOG (6, "Pinning from sections");
2559 /* first pass for the sections */
2560 sgen_find_section_pin_queue_start_end (nursery_section);
2561 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2562 /* identify possible pointers to the insize of large objects */
2563 SGEN_LOG (6, "Pinning from large objects");
2564 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2566 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2567 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2569 #ifdef ENABLE_DTRACE
2570 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2571 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2572 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2576 if (sgen_los_object_is_pinned (bigobj->data)) {
2577 g_assert (finish_up_concurrent_mark);
2580 sgen_los_pin_object (bigobj->data);
2581 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2582 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2583 if (G_UNLIKELY (do_pin_stats))
2584 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2585 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));
2588 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2592 notify_gc_roots (&root_report);
2593 /* second pass for the sections */
2594 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2595 ctx.copy_func = NULL;
2596 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2599 * Concurrent mark never follows references into the nursery. In the start and
2600 * finish pauses we must scan live nursery objects, though.
2602 * In the finish pause we do this conservatively by scanning all nursery objects.
2603 * Previously we would only scan pinned objects here. We assumed that all objects
2604 * that were pinned during the nursery collection immediately preceding this finish
2605 * mark would be pinned again here. Due to the way we get the stack end for the GC
2606 * thread, however, that's not necessarily the case: we scan part of the stack used
2607 * by the GC itself, which changes constantly, so pinning isn't entirely
2610 * The split nursery also complicates things because non-pinned objects can survive
2611 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2613 * In the future we shouldn't do a preceding nursery collection at all and instead
2614 * do the finish pause with promotion from the nursery.
2616 * A further complication arises when we have late-pinned objects from the preceding
2617 * nursery collection. Those are the result of being out of memory when trying to
2618 * evacuate objects. They won't be found from the roots, so we just scan the whole
2621 * Non-concurrent mark evacuates from the nursery, so it's
2622 * sufficient to just scan pinned nursery objects.
2624 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2625 scan_nursery_objects (ctx);
2627 pin_objects_in_nursery (ctx);
2628 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2629 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2632 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2633 if (old_next_pin_slot)
2634 *old_next_pin_slot = sgen_get_pinned_count ();
2637 time_major_pinning += TV_ELAPSED (atv, btv);
2638 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2639 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2641 major_collector.init_to_space ();
2644 * The concurrent collector doesn't move objects, neither on
2645 * the major heap nor in the nursery, so we can mark even
2646 * before pinning has finished. For the non-concurrent
2647 * collector we start the workers after pinning.
2649 if (start_concurrent_mark) {
2650 sgen_workers_start_all_workers ();
2651 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2654 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2655 main_gc_thread = mono_native_thread_self ();
2658 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2659 report_registered_roots ();
2661 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2663 /* registered roots, this includes static fields */
2664 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2665 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2666 scrrjd_normal->scan_func = current_object_ops.scan_object;
2667 scrrjd_normal->heap_start = heap_start;
2668 scrrjd_normal->heap_end = heap_end;
2669 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2670 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2672 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2673 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2674 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2675 scrrjd_wbarrier->heap_start = heap_start;
2676 scrrjd_wbarrier->heap_end = heap_end;
2677 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2678 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2681 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2684 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2685 stdjd->heap_start = heap_start;
2686 stdjd->heap_end = heap_end;
2687 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2690 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2693 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2695 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2696 report_finalizer_roots ();
2698 /* scan the list of objects ready for finalization */
2699 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2700 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2702 if (scan_mod_union) {
2703 g_assert (finish_up_concurrent_mark);
2705 /* Mod union card table */
2706 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2707 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2711 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2712 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2715 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2719 major_finish_copy_or_mark (void)
2721 if (!concurrent_collection_in_progress)
2725 * Prepare the pin queue for the next collection. Since pinning runs on the worker
2726 * threads we must wait for the jobs to finish before we can reset it.
2728 sgen_workers_wait_for_jobs_finished ();
2729 sgen_finish_pinning ();
2731 sgen_pin_stats_reset ();
2733 if (do_concurrent_checks)
2734 check_nursery_is_clean ();
2738 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2740 MONO_GC_BEGIN (GENERATION_OLD);
2741 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2743 current_collection_generation = GENERATION_OLD;
2744 #ifndef DISABLE_PERFCOUNTERS
2745 mono_perfcounters->gc_collections1++;
2748 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2750 sgen_cement_reset ();
2753 g_assert (major_collector.is_concurrent);
2754 concurrent_collection_in_progress = TRUE;
2756 current_object_ops = major_collector.major_concurrent_ops;
2758 current_object_ops = major_collector.major_ops;
2761 reset_pinned_from_failed_allocation ();
2763 sgen_memgov_major_collection_start ();
2765 //count_ref_nonref_objs ();
2766 //consistency_check ();
2768 check_scan_starts ();
2771 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2772 gc_stats.major_gc_count ++;
2774 if (major_collector.start_major_collection)
2775 major_collector.start_major_collection ();
2777 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent, FALSE, FALSE, FALSE);
2778 major_finish_copy_or_mark ();
2782 wait_for_workers_to_finish (void)
2784 while (!sgen_workers_all_done ())
2789 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_whole_nursery)
2791 ScannedObjectCounts counts;
2792 LOSObject *bigobj, *prevbo;
2798 if (concurrent_collection_in_progress) {
2799 sgen_workers_signal_start_nursery_collection_and_wait ();
2801 current_object_ops = major_collector.major_concurrent_ops;
2803 major_copy_or_mark_from_roots (NULL, FALSE, TRUE, TRUE, scan_whole_nursery);
2805 sgen_workers_signal_finish_nursery_collection ();
2807 major_finish_copy_or_mark ();
2808 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2810 sgen_workers_join ();
2812 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2814 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2815 main_gc_thread = NULL;
2818 if (do_concurrent_checks)
2819 check_nursery_is_clean ();
2821 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2822 current_object_ops = major_collector.major_ops;
2826 * The workers have stopped so we need to finish gray queue
2827 * work that might result from finalization in the main GC
2828 * thread. Redirection must therefore be turned off.
2830 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2831 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2833 /* all the objects in the heap */
2834 finish_gray_stack (GENERATION_OLD, &gray_queue);
2836 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2838 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2841 * The (single-threaded) finalization code might have done
2842 * some copying/marking so we can only reset the GC thread's
2843 * worker data here instead of earlier when we joined the
2846 sgen_workers_reset_data ();
2848 if (objects_pinned) {
2849 g_assert (!concurrent_collection_in_progress);
2852 * This is slow, but we just OOM'd.
2854 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2855 * queue is laid out at this point.
2857 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2859 * We need to reestablish all pinned nursery objects in the pin queue
2860 * because they're needed for fragment creation. Unpinning happens by
2861 * walking the whole queue, so it's not necessary to reestablish where major
2862 * heap block pins are - all we care is that they're still in there
2865 sgen_optimize_pin_queue ();
2866 sgen_find_section_pin_queue_start_end (nursery_section);
2870 reset_heap_boundaries ();
2871 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2873 if (!concurrent_collection_in_progress) {
2874 /* walk the pin_queue, build up the fragment list of free memory, unmark
2875 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2878 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2881 /* prepare the pin queue for the next collection */
2882 sgen_finish_pinning ();
2884 /* Clear TLABs for all threads */
2885 sgen_clear_tlabs ();
2887 sgen_pin_stats_reset ();
2890 sgen_cement_clear_below_threshold ();
2892 if (check_mark_bits_after_major_collection)
2893 sgen_check_heap_marked (concurrent_collection_in_progress);
2896 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2899 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2901 /* sweep the big objects list */
2903 for (bigobj = los_object_list; bigobj;) {
2904 g_assert (!object_is_pinned (bigobj->data));
2905 if (sgen_los_object_is_pinned (bigobj->data)) {
2906 sgen_los_unpin_object (bigobj->data);
2907 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2910 /* not referenced anywhere, so we can free it */
2912 prevbo->next = bigobj->next;
2914 los_object_list = bigobj->next;
2916 bigobj = bigobj->next;
2917 sgen_los_free_object (to_free);
2921 bigobj = bigobj->next;
2925 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2930 time_major_los_sweep += TV_ELAPSED (atv, btv);
2932 major_collector.sweep ();
2934 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2937 time_major_sweep += TV_ELAPSED (btv, atv);
2940 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2942 if (fin_ready_list || critical_fin_list) {
2943 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2944 mono_gc_finalize_notify ();
2947 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2949 sgen_memgov_major_collection_end ();
2950 current_collection_generation = -1;
2952 memset (&counts, 0, sizeof (ScannedObjectCounts));
2953 major_collector.finish_major_collection (&counts);
2955 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2957 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2958 if (concurrent_collection_in_progress)
2959 concurrent_collection_in_progress = FALSE;
2961 check_scan_starts ();
2963 binary_protocol_flush_buffers (FALSE);
2965 //consistency_check ();
2967 MONO_GC_END (GENERATION_OLD);
2968 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2972 major_do_collection (const char *reason)
2974 TV_DECLARE (time_start);
2975 TV_DECLARE (time_end);
2976 size_t old_next_pin_slot;
2978 if (disable_major_collections)
2981 if (major_collector.get_and_reset_num_major_objects_marked) {
2982 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2983 g_assert (!num_marked);
2986 /* world must be stopped already */
2987 TV_GETTIME (time_start);
2989 major_start_collection (FALSE, &old_next_pin_slot);
2990 major_finish_collection (reason, old_next_pin_slot, FALSE);
2992 TV_GETTIME (time_end);
2993 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2995 /* FIXME: also report this to the user, preferably in gc-end. */
2996 if (major_collector.get_and_reset_num_major_objects_marked)
2997 major_collector.get_and_reset_num_major_objects_marked ();
2999 return bytes_pinned_from_failed_allocation > 0;
3003 major_start_concurrent_collection (const char *reason)
3005 TV_DECLARE (time_start);
3006 TV_DECLARE (time_end);
3007 long long num_objects_marked;
3009 if (disable_major_collections)
3012 TV_GETTIME (time_start);
3013 SGEN_TV_GETTIME (time_major_conc_collection_start);
3015 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3016 g_assert (num_objects_marked == 0);
3018 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3019 binary_protocol_concurrent_start ();
3021 // FIXME: store reason and pass it when finishing
3022 major_start_collection (TRUE, NULL);
3024 gray_queue_redirect (&gray_queue);
3026 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3027 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3029 TV_GETTIME (time_end);
3030 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3032 current_collection_generation = -1;
3036 * Returns whether the major collection has finished.
3039 major_should_finish_concurrent_collection (void)
3041 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
3042 return sgen_workers_all_done ();
3046 major_update_concurrent_collection (void)
3048 TV_DECLARE (total_start);
3049 TV_DECLARE (total_end);
3051 TV_GETTIME (total_start);
3053 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3054 binary_protocol_concurrent_update ();
3056 major_collector.update_cardtable_mod_union ();
3057 sgen_los_update_cardtable_mod_union ();
3059 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3061 TV_GETTIME (total_end);
3062 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3066 major_finish_concurrent_collection (void)
3068 TV_DECLARE (total_start);
3069 TV_DECLARE (total_end);
3070 gboolean late_pinned;
3071 SgenGrayQueue unpin_queue;
3072 memset (&unpin_queue, 0, sizeof (unpin_queue));
3074 TV_GETTIME (total_start);
3076 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3077 binary_protocol_concurrent_finish ();
3080 * The major collector can add global remsets which are processed in the finishing
3081 * nursery collection, below. That implies that the workers must have finished
3082 * marking before the nursery collection is allowed to run, otherwise we might miss
3085 wait_for_workers_to_finish ();
3087 SGEN_TV_GETTIME (time_major_conc_collection_end);
3088 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3090 major_collector.update_cardtable_mod_union ();
3091 sgen_los_update_cardtable_mod_union ();
3093 late_pinned = collect_nursery (&unpin_queue, TRUE);
3095 if (mod_union_consistency_check)
3096 sgen_check_mod_union_consistency ();
3098 current_collection_generation = GENERATION_OLD;
3099 major_finish_collection ("finishing", -1, late_pinned);
3101 if (whole_heap_check_before_collection)
3102 sgen_check_whole_heap (FALSE);
3104 unpin_objects_from_queue (&unpin_queue);
3105 sgen_gray_object_queue_deinit (&unpin_queue);
3107 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3109 TV_GETTIME (total_end);
3110 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3112 current_collection_generation = -1;
3116 * Ensure an allocation request for @size will succeed by freeing enough memory.
3118 * LOCKING: The GC lock MUST be held.
3121 sgen_ensure_free_space (size_t size)
3123 int generation_to_collect = -1;
3124 const char *reason = NULL;
3127 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3128 if (sgen_need_major_collection (size)) {
3129 reason = "LOS overflow";
3130 generation_to_collect = GENERATION_OLD;
3133 if (degraded_mode) {
3134 if (sgen_need_major_collection (size)) {
3135 reason = "Degraded mode overflow";
3136 generation_to_collect = GENERATION_OLD;
3138 } else if (sgen_need_major_collection (size)) {
3139 reason = "Minor allowance";
3140 generation_to_collect = GENERATION_OLD;
3142 generation_to_collect = GENERATION_NURSERY;
3143 reason = "Nursery full";
3147 if (generation_to_collect == -1) {
3148 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3149 generation_to_collect = GENERATION_OLD;
3150 reason = "Finish concurrent collection";
3154 if (generation_to_collect == -1)
3156 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3160 * LOCKING: Assumes the GC lock is held.
3163 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3165 TV_DECLARE (gc_start);
3166 TV_DECLARE (gc_end);
3167 TV_DECLARE (gc_total_start);
3168 TV_DECLARE (gc_total_end);
3169 GGTimingInfo infos [2];
3170 int overflow_generation_to_collect = -1;
3171 int oldest_generation_collected = generation_to_collect;
3172 const char *overflow_reason = NULL;
3174 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3176 binary_protocol_collection_force (generation_to_collect);
3178 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3180 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3182 TV_GETTIME (gc_start);
3184 sgen_stop_world (generation_to_collect);
3186 TV_GETTIME (gc_total_start);
3188 if (concurrent_collection_in_progress) {
3190 * We update the concurrent collection. If it finished, we're done. If
3191 * not, and we've been asked to do a nursery collection, we do that.
3193 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3196 major_finish_concurrent_collection ();
3197 oldest_generation_collected = GENERATION_OLD;
3199 sgen_workers_signal_start_nursery_collection_and_wait ();
3201 major_update_concurrent_collection ();
3202 if (generation_to_collect == GENERATION_NURSERY)
3203 collect_nursery (NULL, FALSE);
3205 sgen_workers_signal_finish_nursery_collection ();
3212 * If we've been asked to do a major collection, and the major collector wants to
3213 * run synchronously (to evacuate), we set the flag to do that.
3215 if (generation_to_collect == GENERATION_OLD &&
3216 allow_synchronous_major &&
3217 major_collector.want_synchronous_collection &&
3218 *major_collector.want_synchronous_collection) {
3219 wait_to_finish = TRUE;
3222 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3225 * There's no concurrent collection in progress. Collect the generation we're asked
3226 * to collect. If the major collector is concurrent and we're not forced to wait,
3227 * start a concurrent collection.
3229 // FIXME: extract overflow reason
3230 if (generation_to_collect == GENERATION_NURSERY) {
3231 if (collect_nursery (NULL, FALSE)) {
3232 overflow_generation_to_collect = GENERATION_OLD;
3233 overflow_reason = "Minor overflow";
3236 if (major_collector.is_concurrent && !wait_to_finish) {
3237 collect_nursery (NULL, FALSE);
3238 major_start_concurrent_collection (reason);
3239 // FIXME: set infos[0] properly
3243 if (major_do_collection (reason)) {
3244 overflow_generation_to_collect = GENERATION_NURSERY;
3245 overflow_reason = "Excessive pinning";
3249 TV_GETTIME (gc_end);
3251 memset (infos, 0, sizeof (infos));
3252 infos [0].generation = generation_to_collect;
3253 infos [0].reason = reason;
3254 infos [0].is_overflow = FALSE;
3255 infos [1].generation = -1;
3256 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3258 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3260 if (overflow_generation_to_collect != -1) {
3262 * We need to do an overflow collection, either because we ran out of memory
3263 * or the nursery is fully pinned.
3266 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3267 infos [1].generation = overflow_generation_to_collect;
3268 infos [1].reason = overflow_reason;
3269 infos [1].is_overflow = TRUE;
3270 infos [1].total_time = gc_end;
3272 if (overflow_generation_to_collect == GENERATION_NURSERY)
3273 collect_nursery (NULL, FALSE);
3275 major_do_collection (overflow_reason);
3277 TV_GETTIME (gc_end);
3278 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3280 /* keep events symmetric */
3281 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3283 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3286 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3288 /* this also sets the proper pointers for the next allocation */
3289 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3290 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3291 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3292 sgen_dump_pin_queue ();
3297 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3299 TV_GETTIME (gc_total_end);
3300 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3302 sgen_restart_world (oldest_generation_collected, infos);
3304 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3308 * ######################################################################
3309 * ######## Memory allocation from the OS
3310 * ######################################################################
3311 * This section of code deals with getting memory from the OS and
3312 * allocating memory for GC-internal data structures.
3313 * Internal memory can be handled with a freelist for small objects.
3319 G_GNUC_UNUSED static void
3320 report_internal_mem_usage (void)
3322 printf ("Internal memory usage:\n");
3323 sgen_report_internal_mem_usage ();
3324 printf ("Pinned memory usage:\n");
3325 major_collector.report_pinned_memory_usage ();
3329 * ######################################################################
3330 * ######## Finalization support
3331 * ######################################################################
3334 static inline gboolean
3335 sgen_major_is_object_alive (void *object)
3339 /* Oldgen objects can be pinned and forwarded too */
3340 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3344 * FIXME: major_collector.is_object_live() also calculates the
3345 * size. Avoid the double calculation.
3347 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3348 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3349 return sgen_los_object_is_pinned (object);
3351 return major_collector.is_object_live (object);
3355 * If the object has been forwarded it means it's still referenced from a root.
3356 * If it is pinned it's still alive as well.
3357 * A LOS object is only alive if we have pinned it.
3358 * Return TRUE if @obj is ready to be finalized.
3360 static inline gboolean
3361 sgen_is_object_alive (void *object)
3363 if (ptr_in_nursery (object))
3364 return sgen_nursery_is_object_alive (object);
3366 return sgen_major_is_object_alive (object);
3370 * This function returns true if @object is either alive or it belongs to the old gen
3371 * and we're currently doing a minor collection.
3374 sgen_is_object_alive_for_current_gen (char *object)
3376 if (ptr_in_nursery (object))
3377 return sgen_nursery_is_object_alive (object);
3379 if (current_collection_generation == GENERATION_NURSERY)
3382 return sgen_major_is_object_alive (object);
3386 * This function returns true if @object is either alive and belongs to the
3387 * current collection - major collections are full heap, so old gen objects
3388 * are never alive during a minor collection.
3391 sgen_is_object_alive_and_on_current_collection (char *object)
3393 if (ptr_in_nursery (object))
3394 return sgen_nursery_is_object_alive (object);
3396 if (current_collection_generation == GENERATION_NURSERY)
3399 return sgen_major_is_object_alive (object);
3404 sgen_gc_is_object_ready_for_finalization (void *object)
3406 return !sgen_is_object_alive (object);
3410 has_critical_finalizer (MonoObject *obj)
3414 if (!mono_defaults.critical_finalizer_object)
3417 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3419 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3423 is_finalization_aware (MonoObject *obj)
3425 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3426 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3430 sgen_queue_finalization_entry (MonoObject *obj)
3432 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3433 gboolean critical = has_critical_finalizer (obj);
3434 entry->object = obj;
3436 entry->next = critical_fin_list;
3437 critical_fin_list = entry;
3439 entry->next = fin_ready_list;
3440 fin_ready_list = entry;
3443 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3444 fin_callbacks.object_queued_for_finalization (obj);
3446 #ifdef ENABLE_DTRACE
3447 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3448 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3449 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3450 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3451 vt->klass->name_space, vt->klass->name, gen, critical);
3457 sgen_object_is_live (void *obj)
3459 return sgen_is_object_alive_and_on_current_collection (obj);
3462 /* LOCKING: requires that the GC lock is held */
3464 null_ephemerons_for_domain (MonoDomain *domain)
3466 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3469 MonoObject *object = (MonoObject*)current->array;
3472 SGEN_ASSERT (0, object->vtable, "Can't have objects without vtables.");
3474 if (object && object->vtable->domain == domain) {
3475 EphemeronLinkNode *tmp = current;
3478 prev->next = current->next;
3480 ephemeron_list = current->next;
3482 current = current->next;
3483 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3486 current = current->next;
3491 /* LOCKING: requires that the GC lock is held */
3493 clear_unreachable_ephemerons (ScanCopyContext ctx)
3495 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3496 GrayQueue *queue = ctx.queue;
3497 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3499 Ephemeron *cur, *array_end;
3503 char *object = current->array;
3505 if (!sgen_is_object_alive_for_current_gen (object)) {
3506 EphemeronLinkNode *tmp = current;
3508 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3511 prev->next = current->next;
3513 ephemeron_list = current->next;
3515 current = current->next;
3516 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3521 copy_func ((void**)&object, queue);
3522 current->array = object;
3524 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3526 array = (MonoArray*)object;
3527 cur = mono_array_addr (array, Ephemeron, 0);
3528 array_end = cur + mono_array_length_fast (array);
3529 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3531 for (; cur < array_end; ++cur) {
3532 char *key = (char*)cur->key;
3534 if (!key || key == tombstone)
3537 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3538 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3539 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3541 if (!sgen_is_object_alive_for_current_gen (key)) {
3542 cur->key = tombstone;
3548 current = current->next;
3553 LOCKING: requires that the GC lock is held
3555 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3558 mark_ephemerons_in_range (ScanCopyContext ctx)
3560 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3561 GrayQueue *queue = ctx.queue;
3562 int nothing_marked = 1;
3563 EphemeronLinkNode *current = ephemeron_list;
3565 Ephemeron *cur, *array_end;
3568 for (current = ephemeron_list; current; current = current->next) {
3569 char *object = current->array;
3570 SGEN_LOG (5, "Ephemeron array at %p", object);
3572 /*It has to be alive*/
3573 if (!sgen_is_object_alive_for_current_gen (object)) {
3574 SGEN_LOG (5, "\tnot reachable");
3578 copy_func ((void**)&object, queue);
3580 array = (MonoArray*)object;
3581 cur = mono_array_addr (array, Ephemeron, 0);
3582 array_end = cur + mono_array_length_fast (array);
3583 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3585 for (; cur < array_end; ++cur) {
3586 char *key = cur->key;
3588 if (!key || key == tombstone)
3591 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3592 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3593 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3595 if (sgen_is_object_alive_for_current_gen (key)) {
3596 char *value = cur->value;
3598 copy_func ((void**)&cur->key, queue);
3600 if (!sgen_is_object_alive_for_current_gen (value))
3602 copy_func ((void**)&cur->value, queue);
3608 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3609 return nothing_marked;
3613 mono_gc_invoke_finalizers (void)
3615 FinalizeReadyEntry *entry = NULL;
3616 gboolean entry_is_critical = FALSE;
3619 /* FIXME: batch to reduce lock contention */
3620 while (fin_ready_list || critical_fin_list) {
3624 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3626 /* We have finalized entry in the last
3627 interation, now we need to remove it from
3630 *list = entry->next;
3632 FinalizeReadyEntry *e = *list;
3633 while (e->next != entry)
3635 e->next = entry->next;
3637 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3641 /* Now look for the first non-null entry. */
3642 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3645 entry_is_critical = FALSE;
3647 entry_is_critical = TRUE;
3648 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3653 g_assert (entry->object);
3654 num_ready_finalizers--;
3655 obj = entry->object;
3656 entry->object = NULL;
3657 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3665 g_assert (entry->object == NULL);
3667 /* the object is on the stack so it is pinned */
3668 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3669 mono_gc_run_finalize (obj, NULL);
3676 mono_gc_pending_finalizers (void)
3678 return fin_ready_list || critical_fin_list;
3682 * ######################################################################
3683 * ######## registered roots support
3684 * ######################################################################
3688 * We do not coalesce roots.
3691 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3693 RootRecord new_root;
3696 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3697 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3698 /* we allow changing the size and the descriptor (for thread statics etc) */
3700 size_t old_size = root->end_root - start;
3701 root->end_root = start + size;
3702 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3703 ((root->root_desc == 0) && (descr == NULL)));
3704 root->root_desc = (mword)descr;
3706 roots_size -= old_size;
3712 new_root.end_root = start + size;
3713 new_root.root_desc = (mword)descr;
3715 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3718 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);
3725 mono_gc_register_root (char *start, size_t size, void *descr)
3727 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3731 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3733 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3737 mono_gc_deregister_root (char* addr)
3743 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3744 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3745 roots_size -= (root.end_root - addr);
3751 * ######################################################################
3752 * ######## Thread handling (stop/start code)
3753 * ######################################################################
3756 unsigned int sgen_global_stop_count = 0;
3759 sgen_get_current_collection_generation (void)
3761 return current_collection_generation;
3765 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3767 gc_callbacks = *callbacks;
3771 mono_gc_get_gc_callbacks ()
3773 return &gc_callbacks;
3776 /* Variables holding start/end nursery so it won't have to be passed at every call */
3777 static void *scan_area_arg_start, *scan_area_arg_end;
3780 mono_gc_conservatively_scan_area (void *start, void *end)
3782 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3786 mono_gc_scan_object (void *obj, void *gc_data)
3788 UserCopyOrMarkData *data = gc_data;
3789 current_object_ops.copy_or_mark_object (&obj, data->queue);
3794 * Mark from thread stacks and registers.
3797 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3799 SgenThreadInfo *info;
3801 scan_area_arg_start = start_nursery;
3802 scan_area_arg_end = end_nursery;
3804 FOREACH_THREAD (info) {
3806 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);
3809 if (info->gc_disabled) {
3810 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);
3813 if (!mono_thread_info_is_live (info)) {
3814 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);
3817 g_assert (info->suspend_done);
3818 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 ());
3819 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3820 UserCopyOrMarkData data = { NULL, queue };
3821 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3822 } else if (!precise) {
3823 if (!conservative_stack_mark) {
3824 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3825 conservative_stack_mark = TRUE;
3827 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3832 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3833 start_nursery, end_nursery, PIN_TYPE_STACK);
3835 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3836 start_nursery, end_nursery, PIN_TYPE_STACK);
3839 } END_FOREACH_THREAD
3843 ptr_on_stack (void *ptr)
3845 gpointer stack_start = &stack_start;
3846 SgenThreadInfo *info = mono_thread_info_current ();
3848 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3854 sgen_thread_register (SgenThreadInfo* info, void *addr)
3857 guint8 *staddr = NULL;
3859 #ifndef HAVE_KW_THREAD
3860 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3862 g_assert (!mono_native_tls_get_value (thread_info_key));
3863 mono_native_tls_set_value (thread_info_key, info);
3865 sgen_thread_info = info;
3868 #ifdef SGEN_POSIX_STW
3869 info->stop_count = -1;
3873 info->stack_start = NULL;
3874 info->stopped_ip = NULL;
3875 info->stopped_domain = NULL;
3877 memset (&info->ctx, 0, sizeof (MonoContext));
3879 memset (&info->regs, 0, sizeof (info->regs));
3882 sgen_init_tlab_info (info);
3884 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3886 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3887 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3890 info->stack_start_limit = staddr;
3892 info->stack_end = staddr + stsize;
3894 gsize stack_bottom = (gsize)addr;
3895 stack_bottom += 4095;
3896 stack_bottom &= ~4095;
3897 info->stack_end = (char*)stack_bottom;
3900 #ifdef HAVE_KW_THREAD
3901 stack_end = info->stack_end;
3904 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3906 if (gc_callbacks.thread_attach_func)
3907 info->runtime_data = gc_callbacks.thread_attach_func ();
3912 sgen_thread_detach (SgenThreadInfo *p)
3914 /* If a delegate is passed to native code and invoked on a thread we dont
3915 * know about, the jit will register it with mono_jit_thread_attach, but
3916 * we have no way of knowing when that thread goes away. SGen has a TSD
3917 * so we assume that if the domain is still registered, we can detach
3920 if (mono_domain_get ())
3921 mono_thread_detach_internal (mono_thread_internal_current ());
3925 sgen_thread_unregister (SgenThreadInfo *p)
3927 MonoNativeThreadId tid;
3929 tid = mono_thread_info_get_tid (p);
3930 binary_protocol_thread_unregister ((gpointer)tid);
3931 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3933 #ifndef HAVE_KW_THREAD
3934 mono_native_tls_set_value (thread_info_key, NULL);
3936 sgen_thread_info = NULL;
3939 if (p->info.runtime_thread)
3940 mono_threads_add_joinable_thread ((gpointer)tid);
3942 if (gc_callbacks.thread_detach_func) {
3943 gc_callbacks.thread_detach_func (p->runtime_data);
3944 p->runtime_data = NULL;
3950 sgen_thread_attach (SgenThreadInfo *info)
3953 /*this is odd, can we get attached before the gc is inited?*/
3957 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3958 info->runtime_data = gc_callbacks.thread_attach_func ();
3961 mono_gc_register_thread (void *baseptr)
3963 return mono_thread_info_attach (baseptr) != NULL;
3967 * mono_gc_set_stack_end:
3969 * Set the end of the current threads stack to STACK_END. The stack space between
3970 * STACK_END and the real end of the threads stack will not be scanned during collections.
3973 mono_gc_set_stack_end (void *stack_end)
3975 SgenThreadInfo *info;
3978 info = mono_thread_info_current ();
3980 g_assert (stack_end < info->stack_end);
3981 info->stack_end = stack_end;
3986 #if USE_PTHREAD_INTERCEPT
3990 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3992 return pthread_create (new_thread, attr, start_routine, arg);
3996 mono_gc_pthread_join (pthread_t thread, void **retval)
3998 return pthread_join (thread, retval);
4002 mono_gc_pthread_detach (pthread_t thread)
4004 return pthread_detach (thread);
4008 mono_gc_pthread_exit (void *retval)
4010 mono_thread_info_detach ();
4011 pthread_exit (retval);
4012 g_assert_not_reached ();
4015 #endif /* USE_PTHREAD_INTERCEPT */
4018 * ######################################################################
4019 * ######## Write barriers
4020 * ######################################################################
4024 * Note: the write barriers first do the needed GC work and then do the actual store:
4025 * this way the value is visible to the conservative GC scan after the write barrier
4026 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4027 * the conservative scan, otherwise by the remembered set scan.
4030 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4032 HEAVY_STAT (++stat_wbarrier_set_field);
4033 if (ptr_in_nursery (field_ptr)) {
4034 *(void**)field_ptr = value;
4037 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4039 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4041 remset.wbarrier_set_field (obj, field_ptr, value);
4045 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4047 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4048 if (ptr_in_nursery (slot_ptr)) {
4049 *(void**)slot_ptr = value;
4052 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4054 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4056 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4060 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4062 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4063 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4064 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4065 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4069 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4070 if (binary_protocol_is_heavy_enabled ()) {
4072 for (i = 0; i < count; ++i) {
4073 gpointer dest = (gpointer*)dest_ptr + i;
4074 gpointer obj = *((gpointer*)src_ptr + i);
4076 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4081 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4085 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4089 HEAVY_STAT (++stat_wbarrier_generic_store);
4091 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4092 /* FIXME: ptr_in_heap must be called with the GC lock held */
4093 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4094 char *start = sgen_find_object_for_ptr (ptr);
4095 MonoObject *value = *(MonoObject**)ptr;
4099 MonoObject *obj = (MonoObject*)start;
4100 if (obj->vtable->domain != value->vtable->domain)
4101 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4107 obj = *(gpointer*)ptr;
4109 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4111 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4112 SGEN_LOG (8, "Skipping remset at %p", ptr);
4117 * We need to record old->old pointer locations for the
4118 * concurrent collector.
4120 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4121 SGEN_LOG (8, "Skipping remset at %p", ptr);
4125 SGEN_LOG (8, "Adding remset at %p", ptr);
4127 remset.wbarrier_generic_nostore (ptr);
4131 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4133 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4134 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4135 if (ptr_in_nursery (value))
4136 mono_gc_wbarrier_generic_nostore (ptr);
4137 sgen_dummy_use (value);
4140 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4141 * as an atomic operation with release semantics.
4144 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4146 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4148 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4150 InterlockedWritePointer (ptr, value);
4152 if (ptr_in_nursery (value))
4153 mono_gc_wbarrier_generic_nostore (ptr);
4155 sgen_dummy_use (value);
4158 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4160 mword *dest = _dest;
4165 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4167 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4170 size -= SIZEOF_VOID_P;
4175 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4177 #define HANDLE_PTR(ptr,obj) do { \
4178 gpointer o = *(gpointer*)(ptr); \
4180 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4181 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4186 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4188 #define SCAN_OBJECT_NOVTABLE
4189 #include "sgen-scan-object.h"
4194 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4196 HEAVY_STAT (++stat_wbarrier_value_copy);
4197 g_assert (klass->valuetype);
4199 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4201 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4202 size_t element_size = mono_class_value_size (klass, NULL);
4203 size_t size = count * element_size;
4204 mono_gc_memmove_atomic (dest, src, size);
4208 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4209 if (binary_protocol_is_heavy_enabled ()) {
4210 size_t element_size = mono_class_value_size (klass, NULL);
4212 for (i = 0; i < count; ++i) {
4213 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4214 (char*)src + i * element_size - sizeof (MonoObject),
4215 (mword) klass->gc_descr);
4220 remset.wbarrier_value_copy (dest, src, count, klass);
4224 * mono_gc_wbarrier_object_copy:
4226 * Write barrier to call when obj is the result of a clone or copy of an object.
4229 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4233 HEAVY_STAT (++stat_wbarrier_object_copy);
4235 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4236 size = mono_object_class (obj)->instance_size;
4237 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4238 size - sizeof (MonoObject));
4242 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4243 if (binary_protocol_is_heavy_enabled ())
4244 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4247 remset.wbarrier_object_copy (obj, src);
4252 * ######################################################################
4253 * ######## Other mono public interface functions.
4254 * ######################################################################
4257 #define REFS_SIZE 128
4260 MonoGCReferences callback;
4264 MonoObject *refs [REFS_SIZE];
4265 uintptr_t offsets [REFS_SIZE];
4269 #define HANDLE_PTR(ptr,obj) do { \
4271 if (hwi->count == REFS_SIZE) { \
4272 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4276 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4277 hwi->refs [hwi->count++] = *(ptr); \
4282 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4284 mword desc = sgen_obj_get_descriptor (start);
4286 #include "sgen-scan-object.h"
4290 walk_references (char *start, size_t size, void *data)
4292 HeapWalkInfo *hwi = data;
4295 collect_references (hwi, start, size);
4296 if (hwi->count || !hwi->called)
4297 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4301 * mono_gc_walk_heap:
4302 * @flags: flags for future use
4303 * @callback: a function pointer called for each object in the heap
4304 * @data: a user data pointer that is passed to callback
4306 * This function can be used to iterate over all the live objects in the heap:
4307 * for each object, @callback is invoked, providing info about the object's
4308 * location in memory, its class, its size and the objects it references.
4309 * For each referenced object it's offset from the object address is
4310 * reported in the offsets array.
4311 * The object references may be buffered, so the callback may be invoked
4312 * multiple times for the same object: in all but the first call, the size
4313 * argument will be zero.
4314 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4315 * profiler event handler.
4317 * Returns: a non-zero value if the GC doesn't support heap walking
4320 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4325 hwi.callback = callback;
4328 sgen_clear_nursery_fragments ();
4329 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4331 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4332 sgen_los_iterate_objects (walk_references, &hwi);
4338 mono_gc_collect (int generation)
4343 sgen_perform_collection (0, generation, "user request", TRUE);
4348 mono_gc_max_generation (void)
4354 mono_gc_collection_count (int generation)
4356 if (generation == 0)
4357 return gc_stats.minor_gc_count;
4358 return gc_stats.major_gc_count;
4362 mono_gc_get_used_size (void)
4366 tot = los_memory_usage;
4367 tot += nursery_section->next_data - nursery_section->data;
4368 tot += major_collector.get_used_size ();
4369 /* FIXME: account for pinned objects */
4375 mono_gc_get_los_limit (void)
4377 return MAX_SMALL_OBJ_SIZE;
4381 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4383 mono_unichar2 *new_end = str->chars + new_length;
4385 /* zero the discarded string. This null-delimits the string and allows
4386 * the space to be reclaimed by SGen. */
4388 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4389 CHECK_CANARY_FOR_OBJECT (str);
4390 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4391 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4393 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4396 str->length = new_length;
4400 mono_gc_user_markers_supported (void)
4406 mono_object_is_alive (MonoObject* o)
4412 mono_gc_get_generation (MonoObject *obj)
4414 if (ptr_in_nursery (obj))
4420 mono_gc_enable_events (void)
4425 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4427 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4431 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4433 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4437 mono_gc_weak_link_get (void **link_addr)
4439 void * volatile *link_addr_volatile;
4443 link_addr_volatile = link_addr;
4444 ptr = (void*)*link_addr_volatile;
4446 * At this point we have a hidden pointer. If the GC runs
4447 * here, it will not recognize the hidden pointer as a
4448 * reference, and if the object behind it is not referenced
4449 * elsewhere, it will be freed. Once the world is restarted
4450 * we reveal the pointer, giving us a pointer to a freed
4451 * object. To make sure we don't return it, we load the
4452 * hidden pointer again. If it's still the same, we can be
4453 * sure the object reference is valid.
4456 obj = (MonoObject*) REVEAL_POINTER (ptr);
4460 mono_memory_barrier ();
4463 * During the second bridge processing step the world is
4464 * running again. That step processes all weak links once
4465 * more to null those that refer to dead objects. Before that
4466 * is completed, those links must not be followed, so we
4467 * conservatively wait for bridge processing when any weak
4468 * link is dereferenced.
4470 if (G_UNLIKELY (bridge_processing_in_progress))
4471 mono_gc_wait_for_bridge_processing ();
4473 if ((void*)*link_addr_volatile != ptr)
4480 mono_gc_ephemeron_array_add (MonoObject *obj)
4482 EphemeronLinkNode *node;
4486 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4491 node->array = (char*)obj;
4492 node->next = ephemeron_list;
4493 ephemeron_list = node;
4495 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4502 mono_gc_set_allow_synchronous_major (gboolean flag)
4504 if (!major_collector.is_concurrent)
4507 allow_synchronous_major = flag;
4512 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4516 result = func (data);
4517 UNLOCK_INTERRUPTION;
4522 mono_gc_is_gc_thread (void)
4526 result = mono_thread_info_current () != NULL;
4532 is_critical_method (MonoMethod *method)
4534 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4538 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4542 va_start (ap, description_format);
4544 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4545 vfprintf (stderr, description_format, ap);
4547 fprintf (stderr, " - %s", fallback);
4548 fprintf (stderr, "\n");
4554 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4557 double val = strtod (opt, &endptr);
4558 if (endptr == opt) {
4559 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4562 else if (val < min || val > max) {
4563 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4571 thread_in_critical_region (SgenThreadInfo *info)
4573 return info->in_critical_region;
4577 mono_gc_base_init (void)
4579 MonoThreadInfoCallbacks cb;
4582 char *major_collector_opt = NULL;
4583 char *minor_collector_opt = NULL;
4584 size_t max_heap = 0;
4585 size_t soft_limit = 0;
4588 gboolean debug_print_allowance = FALSE;
4589 double allowance_ratio = 0, save_target = 0;
4590 gboolean cement_enabled = TRUE;
4592 mono_counters_init ();
4595 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4598 /* already inited */
4601 /* being inited by another thread */
4605 /* we will init it */
4608 g_assert_not_reached ();
4610 } while (result != 0);
4612 SGEN_TV_GETTIME (sgen_init_timestamp);
4614 LOCK_INIT (gc_mutex);
4616 pagesize = mono_pagesize ();
4617 gc_debug_file = stderr;
4619 cb.thread_register = sgen_thread_register;
4620 cb.thread_detach = sgen_thread_detach;
4621 cb.thread_unregister = sgen_thread_unregister;
4622 cb.thread_attach = sgen_thread_attach;
4623 cb.mono_method_is_critical = (gpointer)is_critical_method;
4624 cb.mono_thread_in_critical_region = thread_in_critical_region;
4626 cb.thread_exit = mono_gc_pthread_exit;
4627 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4630 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4632 LOCK_INIT (sgen_interruption_mutex);
4634 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4635 opts = g_strsplit (env, ",", -1);
4636 for (ptr = opts; *ptr; ++ptr) {
4638 if (g_str_has_prefix (opt, "major=")) {
4639 opt = strchr (opt, '=') + 1;
4640 major_collector_opt = g_strdup (opt);
4641 } else if (g_str_has_prefix (opt, "minor=")) {
4642 opt = strchr (opt, '=') + 1;
4643 minor_collector_opt = g_strdup (opt);
4651 sgen_init_internal_allocator ();
4652 sgen_init_nursery_allocator ();
4653 sgen_init_fin_weak_hash ();
4655 sgen_init_hash_table ();
4656 sgen_init_descriptors ();
4657 sgen_init_gray_queues ();
4659 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4660 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4661 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4662 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4664 #ifndef HAVE_KW_THREAD
4665 mono_native_tls_alloc (&thread_info_key, NULL);
4666 #if defined(__APPLE__) || defined (HOST_WIN32)
4668 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4669 * where the two are the same.
4671 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4675 int tls_offset = -1;
4676 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4677 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4682 * This needs to happen before any internal allocations because
4683 * it inits the small id which is required for hazard pointer
4688 mono_thread_info_attach (&dummy);
4690 if (!minor_collector_opt) {
4691 sgen_simple_nursery_init (&sgen_minor_collector);
4693 if (!strcmp (minor_collector_opt, "simple")) {
4695 sgen_simple_nursery_init (&sgen_minor_collector);
4696 } else if (!strcmp (minor_collector_opt, "split")) {
4697 sgen_split_nursery_init (&sgen_minor_collector);
4699 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4700 goto use_simple_nursery;
4704 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4705 use_marksweep_major:
4706 sgen_marksweep_init (&major_collector);
4707 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4708 sgen_marksweep_conc_init (&major_collector);
4710 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4711 goto use_marksweep_major;
4714 ///* Keep this the default for now */
4715 /* Precise marking is broken on all supported targets. Disable until fixed. */
4716 conservative_stack_mark = TRUE;
4718 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4720 if (major_collector.is_concurrent)
4721 cement_enabled = FALSE;
4724 gboolean usage_printed = FALSE;
4726 for (ptr = opts; *ptr; ++ptr) {
4728 if (!strcmp (opt, ""))
4730 if (g_str_has_prefix (opt, "major="))
4732 if (g_str_has_prefix (opt, "minor="))
4734 if (g_str_has_prefix (opt, "max-heap-size=")) {
4735 size_t max_heap_candidate = 0;
4736 opt = strchr (opt, '=') + 1;
4737 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4738 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4739 if (max_heap != max_heap_candidate)
4740 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4742 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4746 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4747 opt = strchr (opt, '=') + 1;
4748 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4749 if (soft_limit <= 0) {
4750 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4754 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4758 if (g_str_has_prefix (opt, "stack-mark=")) {
4759 opt = strchr (opt, '=') + 1;
4760 if (!strcmp (opt, "precise")) {
4761 conservative_stack_mark = FALSE;
4762 } else if (!strcmp (opt, "conservative")) {
4763 conservative_stack_mark = TRUE;
4765 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4766 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4770 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4771 opt = strchr (opt, '=') + 1;
4772 sgen_set_bridge_implementation (opt);
4775 if (g_str_has_prefix (opt, "toggleref-test")) {
4776 sgen_register_test_toggleref_callback ();
4781 if (g_str_has_prefix (opt, "nursery-size=")) {
4783 opt = strchr (opt, '=') + 1;
4784 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4785 #ifdef SGEN_ALIGN_NURSERY
4786 if ((val & (val - 1))) {
4787 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4791 if (val < SGEN_MAX_NURSERY_WASTE) {
4792 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4793 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4797 sgen_nursery_size = val;
4798 sgen_nursery_bits = 0;
4799 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4802 sgen_nursery_size = val;
4805 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4811 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4813 opt = strchr (opt, '=') + 1;
4814 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4815 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4820 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4822 opt = strchr (opt, '=') + 1;
4823 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4824 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4825 allowance_ratio = val;
4829 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4830 if (!major_collector.is_concurrent) {
4831 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4835 opt = strchr (opt, '=') + 1;
4837 if (!strcmp (opt, "yes")) {
4838 allow_synchronous_major = TRUE;
4839 } else if (!strcmp (opt, "no")) {
4840 allow_synchronous_major = FALSE;
4842 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4847 if (!strcmp (opt, "cementing")) {
4848 cement_enabled = TRUE;
4851 if (!strcmp (opt, "no-cementing")) {
4852 cement_enabled = FALSE;
4856 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4859 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4862 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4867 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4868 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4869 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4870 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4871 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4872 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4873 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4874 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4875 fprintf (stderr, " [no-]cementing\n");
4876 if (major_collector.is_concurrent)
4877 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4878 if (major_collector.print_gc_param_usage)
4879 major_collector.print_gc_param_usage ();
4880 if (sgen_minor_collector.print_gc_param_usage)
4881 sgen_minor_collector.print_gc_param_usage ();
4882 fprintf (stderr, " Experimental options:\n");
4883 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4884 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);
4885 fprintf (stderr, "\n");
4887 usage_printed = TRUE;
4892 if (major_collector.is_concurrent)
4893 sgen_workers_init (1);
4895 if (major_collector_opt)
4896 g_free (major_collector_opt);
4898 if (minor_collector_opt)
4899 g_free (minor_collector_opt);
4903 if (major_collector.is_concurrent && cement_enabled) {
4904 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported on concurrent major collectors.");
4905 cement_enabled = FALSE;
4908 sgen_cement_init (cement_enabled);
4910 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4911 gboolean usage_printed = FALSE;
4913 opts = g_strsplit (env, ",", -1);
4914 for (ptr = opts; ptr && *ptr; ptr ++) {
4916 if (!strcmp (opt, ""))
4918 if (opt [0] >= '0' && opt [0] <= '9') {
4919 gc_debug_level = atoi (opt);
4924 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4925 gc_debug_file = fopen (rf, "wb");
4927 gc_debug_file = stderr;
4930 } else if (!strcmp (opt, "print-allowance")) {
4931 debug_print_allowance = TRUE;
4932 } else if (!strcmp (opt, "print-pinning")) {
4933 do_pin_stats = TRUE;
4934 } else if (!strcmp (opt, "verify-before-allocs")) {
4935 verify_before_allocs = 1;
4936 has_per_allocation_action = TRUE;
4937 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4938 char *arg = strchr (opt, '=') + 1;
4939 verify_before_allocs = atoi (arg);
4940 has_per_allocation_action = TRUE;
4941 } else if (!strcmp (opt, "collect-before-allocs")) {
4942 collect_before_allocs = 1;
4943 has_per_allocation_action = TRUE;
4944 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4945 char *arg = strchr (opt, '=') + 1;
4946 has_per_allocation_action = TRUE;
4947 collect_before_allocs = atoi (arg);
4948 } else if (!strcmp (opt, "verify-before-collections")) {
4949 whole_heap_check_before_collection = TRUE;
4950 } else if (!strcmp (opt, "check-at-minor-collections")) {
4951 consistency_check_at_minor_collection = TRUE;
4952 nursery_clear_policy = CLEAR_AT_GC;
4953 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4954 if (!major_collector.is_concurrent) {
4955 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4958 mod_union_consistency_check = TRUE;
4959 } else if (!strcmp (opt, "check-mark-bits")) {
4960 check_mark_bits_after_major_collection = TRUE;
4961 } else if (!strcmp (opt, "check-nursery-pinned")) {
4962 check_nursery_objects_pinned = TRUE;
4963 } else if (!strcmp (opt, "xdomain-checks")) {
4964 xdomain_checks = TRUE;
4965 } else if (!strcmp (opt, "clear-at-gc")) {
4966 nursery_clear_policy = CLEAR_AT_GC;
4967 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4968 nursery_clear_policy = CLEAR_AT_GC;
4969 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4970 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4971 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4972 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4973 } else if (!strcmp (opt, "check-scan-starts")) {
4974 do_scan_starts_check = TRUE;
4975 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4976 do_verify_nursery = TRUE;
4977 } else if (!strcmp (opt, "check-concurrent")) {
4978 if (!major_collector.is_concurrent) {
4979 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4982 do_concurrent_checks = TRUE;
4983 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4984 do_dump_nursery_content = TRUE;
4985 } else if (!strcmp (opt, "no-managed-allocator")) {
4986 sgen_set_use_managed_allocator (FALSE);
4987 } else if (!strcmp (opt, "disable-minor")) {
4988 disable_minor_collections = TRUE;
4989 } else if (!strcmp (opt, "disable-major")) {
4990 disable_major_collections = TRUE;
4991 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4992 char *filename = strchr (opt, '=') + 1;
4993 nursery_clear_policy = CLEAR_AT_GC;
4994 heap_dump_file = fopen (filename, "w");
4995 if (heap_dump_file) {
4996 fprintf (heap_dump_file, "<sgen-dump>\n");
4997 do_pin_stats = TRUE;
4999 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5000 char *filename = strchr (opt, '=') + 1;
5001 char *colon = strrchr (filename, ':');
5004 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
5005 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
5010 binary_protocol_init (filename, (long long)limit);
5011 } else if (!strcmp (opt, "nursery-canaries")) {
5012 do_verify_nursery = TRUE;
5013 sgen_set_use_managed_allocator (FALSE);
5014 enable_nursery_canaries = TRUE;
5015 } else if (!strcmp (opt, "do-not-finalize")) {
5016 do_not_finalize = TRUE;
5017 } else if (!strcmp (opt, "log-finalizers")) {
5018 log_finalizers = TRUE;
5019 } else if (!sgen_bridge_handle_gc_debug (opt)) {
5020 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5025 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);
5026 fprintf (stderr, "Valid <option>s are:\n");
5027 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5028 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5029 fprintf (stderr, " check-at-minor-collections\n");
5030 fprintf (stderr, " check-mark-bits\n");
5031 fprintf (stderr, " check-nursery-pinned\n");
5032 fprintf (stderr, " verify-before-collections\n");
5033 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5034 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5035 fprintf (stderr, " disable-minor\n");
5036 fprintf (stderr, " disable-major\n");
5037 fprintf (stderr, " xdomain-checks\n");
5038 fprintf (stderr, " check-concurrent\n");
5039 fprintf (stderr, " clear-[nursery-]at-gc\n");
5040 fprintf (stderr, " clear-at-tlab-creation\n");
5041 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5042 fprintf (stderr, " check-scan-starts\n");
5043 fprintf (stderr, " no-managed-allocator\n");
5044 fprintf (stderr, " print-allowance\n");
5045 fprintf (stderr, " print-pinning\n");
5046 fprintf (stderr, " heap-dump=<filename>\n");
5047 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5048 fprintf (stderr, " nursery-canaries\n");
5049 fprintf (stderr, " do-not-finalize\n");
5050 fprintf (stderr, " log-finalizers\n");
5051 sgen_bridge_print_gc_debug_usage ();
5052 fprintf (stderr, "\n");
5054 usage_printed = TRUE;
5060 if (check_mark_bits_after_major_collection)
5061 nursery_clear_policy = CLEAR_AT_GC;
5063 if (major_collector.post_param_init)
5064 major_collector.post_param_init (&major_collector);
5066 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5068 memset (&remset, 0, sizeof (remset));
5070 sgen_card_table_init (&remset);
5076 mono_gc_get_gc_name (void)
5081 static MonoMethod *write_barrier_method;
5084 sgen_is_critical_method (MonoMethod *method)
5086 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5090 sgen_has_critical_method (void)
5092 return write_barrier_method || sgen_has_managed_allocator ();
5098 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5100 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5101 #ifdef SGEN_ALIGN_NURSERY
5102 // if (ptr_in_nursery (ptr)) return;
5104 * Masking out the bits might be faster, but we would have to use 64 bit
5105 * immediates, which might be slower.
5107 mono_mb_emit_ldarg (mb, 0);
5108 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5109 mono_mb_emit_byte (mb, CEE_SHR_UN);
5110 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5111 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5113 if (!major_collector.is_concurrent) {
5114 // if (!ptr_in_nursery (*ptr)) return;
5115 mono_mb_emit_ldarg (mb, 0);
5116 mono_mb_emit_byte (mb, CEE_LDIND_I);
5117 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5118 mono_mb_emit_byte (mb, CEE_SHR_UN);
5119 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5120 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5123 int label_continue1, label_continue2;
5124 int dereferenced_var;
5126 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5127 mono_mb_emit_ldarg (mb, 0);
5128 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5129 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5131 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5132 mono_mb_emit_ldarg (mb, 0);
5133 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5134 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5137 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5140 mono_mb_patch_branch (mb, label_continue_1);
5141 mono_mb_patch_branch (mb, label_continue_2);
5143 // Dereference and store in local var
5144 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5145 mono_mb_emit_ldarg (mb, 0);
5146 mono_mb_emit_byte (mb, CEE_LDIND_I);
5147 mono_mb_emit_stloc (mb, dereferenced_var);
5149 if (!major_collector.is_concurrent) {
5150 // if (*ptr < sgen_get_nursery_start ()) return;
5151 mono_mb_emit_ldloc (mb, dereferenced_var);
5152 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5153 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5155 // if (*ptr >= sgen_get_nursery_end ()) return;
5156 mono_mb_emit_ldloc (mb, dereferenced_var);
5157 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5158 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5165 mono_gc_get_write_barrier (void)
5168 MonoMethodBuilder *mb;
5169 MonoMethodSignature *sig;
5170 #ifdef MANAGED_WBARRIER
5171 int i, nursery_check_labels [3];
5173 #ifdef HAVE_KW_THREAD
5174 int stack_end_offset = -1;
5176 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5177 g_assert (stack_end_offset != -1);
5181 // FIXME: Maybe create a separate version for ctors (the branch would be
5182 // correctly predicted more times)
5183 if (write_barrier_method)
5184 return write_barrier_method;
5186 /* Create the IL version of mono_gc_barrier_generic_store () */
5187 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5188 sig->ret = &mono_defaults.void_class->byval_arg;
5189 sig->params [0] = &mono_defaults.int_class->byval_arg;
5191 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5194 #ifdef MANAGED_WBARRIER
5195 emit_nursery_check (mb, nursery_check_labels);
5197 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5201 LDC_PTR sgen_cardtable
5203 address >> CARD_BITS
5207 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5208 LDC_PTR card_table_mask
5215 mono_mb_emit_ptr (mb, sgen_cardtable);
5216 mono_mb_emit_ldarg (mb, 0);
5217 mono_mb_emit_icon (mb, CARD_BITS);
5218 mono_mb_emit_byte (mb, CEE_SHR_UN);
5219 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5220 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5221 mono_mb_emit_byte (mb, CEE_AND);
5223 mono_mb_emit_byte (mb, CEE_ADD);
5224 mono_mb_emit_icon (mb, 1);
5225 mono_mb_emit_byte (mb, CEE_STIND_I1);
5228 for (i = 0; i < 3; ++i) {
5229 if (nursery_check_labels [i])
5230 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5232 mono_mb_emit_byte (mb, CEE_RET);
5234 mono_mb_emit_ldarg (mb, 0);
5235 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5236 mono_mb_emit_byte (mb, CEE_RET);
5239 res = mono_mb_create_method (mb, sig, 16);
5243 if (write_barrier_method) {
5244 /* Already created */
5245 mono_free_method (res);
5247 /* double-checked locking */
5248 mono_memory_barrier ();
5249 write_barrier_method = res;
5253 return write_barrier_method;
5257 mono_gc_get_description (void)
5259 return g_strdup ("sgen");
5263 mono_gc_set_desktop_mode (void)
5268 mono_gc_is_moving (void)
5274 mono_gc_is_disabled (void)
5280 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5287 sgen_get_nursery_clear_policy (void)
5289 return nursery_clear_policy;
5293 sgen_get_array_fill_vtable (void)
5295 if (!array_fill_vtable) {
5296 static MonoClass klass;
5297 static char _vtable[sizeof(MonoVTable)+8];
5298 MonoVTable* vtable = (MonoVTable*) ALIGN_TO(_vtable, 8);
5301 MonoDomain *domain = mono_get_root_domain ();
5304 klass.element_class = mono_defaults.byte_class;
5306 klass.instance_size = sizeof (MonoArray);
5307 klass.sizes.element_size = 1;
5308 klass.name = "array_filler_type";
5310 vtable->klass = &klass;
5312 vtable->gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5315 array_fill_vtable = vtable;
5317 return array_fill_vtable;
5327 sgen_gc_unlock (void)
5329 gboolean try_free = sgen_try_free_some_memory;
5330 sgen_try_free_some_memory = FALSE;
5331 mono_mutex_unlock (&gc_mutex);
5332 MONO_GC_UNLOCKED ();
5334 mono_thread_hazardous_try_free_some ();
5338 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5340 major_collector.iterate_live_block_ranges (callback);
5344 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5346 major_collector.scan_card_table (FALSE, queue);
5350 sgen_get_major_collector (void)
5352 return &major_collector;
5355 void mono_gc_set_skip_thread (gboolean skip)
5357 SgenThreadInfo *info = mono_thread_info_current ();
5360 info->gc_disabled = skip;
5365 sgen_get_remset (void)
5371 mono_gc_get_vtable_bits (MonoClass *class)
5374 /* FIXME move this to the bridge code */
5375 if (sgen_need_bridge_processing ()) {
5376 switch (sgen_bridge_class_kind (class)) {
5377 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5378 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5379 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5381 case GC_BRIDGE_OPAQUE_CLASS:
5382 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5384 case GC_BRIDGE_TRANSPARENT_CLASS:
5388 if (fin_callbacks.is_class_finalization_aware) {
5389 if (fin_callbacks.is_class_finalization_aware (class))
5390 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5396 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5403 sgen_check_whole_heap_stw (void)
5405 sgen_stop_world (0);
5406 sgen_clear_nursery_fragments ();
5407 sgen_check_whole_heap (FALSE);
5408 sgen_restart_world (0, NULL);
5412 sgen_gc_event_moves (void)
5414 if (moved_objects_idx) {
5415 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5416 moved_objects_idx = 0;
5421 sgen_timestamp (void)
5423 SGEN_TV_DECLARE (timestamp);
5424 SGEN_TV_GETTIME (timestamp);
5425 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5429 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5431 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5432 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5434 fin_callbacks = *callbacks;
5441 #endif /* HAVE_SGEN_GC */