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 SgenRemeberedSet 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;
2027 } FinishRememberedSetScanJobData;
2030 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2032 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2034 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2035 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2040 CopyOrMarkObjectFunc copy_or_mark_func;
2041 ScanObjectFunc scan_func;
2045 } ScanFromRegisteredRootsJobData;
2048 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2050 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2051 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2052 sgen_workers_get_job_gray_queue (worker_data) };
2054 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2055 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2062 } ScanThreadDataJobData;
2065 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2067 ScanThreadDataJobData *job_data = job_data_untyped;
2069 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2070 sgen_workers_get_job_gray_queue (worker_data));
2071 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2075 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2077 FinalizeReadyEntry *list = job_data_untyped;
2078 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2080 scan_finalizer_entries (list, ctx);
2084 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2086 g_assert (concurrent_collection_in_progress);
2087 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2091 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2093 g_assert (concurrent_collection_in_progress);
2094 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2098 verify_scan_starts (char *start, char *end)
2102 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2103 char *addr = nursery_section->scan_starts [i];
2104 if (addr > start && addr < end)
2105 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2110 verify_nursery (void)
2112 char *start, *end, *cur, *hole_start;
2114 if (!do_verify_nursery)
2117 if (nursery_canaries_enabled ())
2118 SGEN_LOG (1, "Checking nursery canaries...");
2120 /*This cleans up unused fragments */
2121 sgen_nursery_allocator_prepare_for_pinning ();
2123 hole_start = start = cur = sgen_get_nursery_start ();
2124 end = sgen_get_nursery_end ();
2129 if (!*(void**)cur) {
2130 cur += sizeof (void*);
2134 if (object_is_forwarded (cur))
2135 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2136 else if (object_is_pinned (cur))
2137 SGEN_LOG (1, "PINNED OBJ %p", cur);
2139 ss = safe_object_get_size ((MonoObject*)cur);
2140 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2141 verify_scan_starts (cur, cur + size);
2142 if (do_dump_nursery_content) {
2143 if (cur > hole_start)
2144 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2145 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 ());
2147 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2148 CHECK_CANARY_FOR_OBJECT (cur);
2149 CANARIFY_SIZE (size);
2157 * Checks that no objects in the nursery are fowarded or pinned. This
2158 * is a precondition to restarting the mutator while doing a
2159 * concurrent collection. Note that we don't clear fragments because
2160 * we depend on that having happened earlier.
2163 check_nursery_is_clean (void)
2167 cur = sgen_get_nursery_start ();
2168 end = sgen_get_nursery_end ();
2173 if (!*(void**)cur) {
2174 cur += sizeof (void*);
2178 g_assert (!object_is_forwarded (cur));
2179 g_assert (!object_is_pinned (cur));
2181 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2182 verify_scan_starts (cur, cur + size);
2189 init_gray_queue (void)
2191 if (sgen_collection_is_concurrent ())
2192 sgen_workers_init_distribute_gray_queue ();
2193 sgen_gray_object_queue_init (&gray_queue, NULL);
2197 * Perform a nursery collection.
2199 * Return whether any objects were late-pinned due to being out of memory.
2202 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2204 gboolean needs_major;
2205 size_t max_garbage_amount;
2207 FinishRememberedSetScanJobData *frssjd;
2208 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2209 ScanThreadDataJobData *stdjd;
2210 mword fragment_total;
2211 ScanCopyContext ctx;
2215 if (disable_minor_collections)
2218 TV_GETTIME (last_minor_collection_start_tv);
2219 atv = last_minor_collection_start_tv;
2221 MONO_GC_BEGIN (GENERATION_NURSERY);
2222 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2226 #ifndef DISABLE_PERFCOUNTERS
2227 mono_perfcounters->gc_collections0++;
2230 current_collection_generation = GENERATION_NURSERY;
2231 current_object_ops = sgen_minor_collector.serial_ops;
2233 reset_pinned_from_failed_allocation ();
2235 check_scan_starts ();
2237 sgen_nursery_alloc_prepare_for_minor ();
2241 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2242 /* FIXME: optimize later to use the higher address where an object can be present */
2243 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2245 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 ()));
2246 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2247 g_assert (nursery_section->size >= max_garbage_amount);
2249 /* world must be stopped already */
2251 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2253 if (xdomain_checks) {
2254 sgen_clear_nursery_fragments ();
2255 sgen_check_for_xdomain_refs ();
2258 nursery_section->next_data = nursery_next;
2260 major_collector.start_nursery_collection ();
2262 sgen_memgov_minor_collection_start ();
2266 gc_stats.minor_gc_count ++;
2268 if (whole_heap_check_before_collection) {
2269 sgen_clear_nursery_fragments ();
2270 sgen_check_whole_heap (finish_up_concurrent_mark);
2272 if (consistency_check_at_minor_collection)
2273 sgen_check_consistency ();
2275 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2277 sgen_process_fin_stage_entries ();
2278 sgen_process_dislink_stage_entries ();
2280 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2282 /* pin from pinned handles */
2283 sgen_init_pinning ();
2284 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2285 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2286 /* pin cemented objects */
2287 sgen_pin_cemented_objects ();
2288 /* identify pinned objects */
2289 sgen_optimize_pin_queue ();
2290 sgen_pinning_setup_section (nursery_section);
2291 ctx.scan_func = NULL;
2292 ctx.copy_func = NULL;
2293 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2294 pin_objects_in_nursery (ctx);
2295 sgen_pinning_trim_queue_to_section (nursery_section);
2298 time_minor_pinning += TV_ELAPSED (btv, atv);
2299 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2300 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2302 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2304 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2305 frssjd->heap_start = sgen_get_nursery_start ();
2306 frssjd->heap_end = nursery_next;
2307 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2309 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2311 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2312 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2314 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2316 /* FIXME: why is this here? */
2317 ctx.scan_func = current_object_ops.scan_object;
2318 ctx.copy_func = NULL;
2319 ctx.queue = &gray_queue;
2320 sgen_drain_gray_stack (-1, ctx);
2322 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2323 report_registered_roots ();
2324 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2325 report_finalizer_roots ();
2327 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2329 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2331 /* registered roots, this includes static fields */
2332 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2333 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2334 scrrjd_normal->scan_func = current_object_ops.scan_object;
2335 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2336 scrrjd_normal->heap_end = nursery_next;
2337 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2338 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2340 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2341 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2342 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2343 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2344 scrrjd_wbarrier->heap_end = nursery_next;
2345 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2346 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2349 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2351 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2354 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2355 stdjd->heap_start = sgen_get_nursery_start ();
2356 stdjd->heap_end = nursery_next;
2357 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2360 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2363 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2365 g_assert (!sgen_collection_is_concurrent ());
2367 /* Scan the list of objects ready for finalization. If */
2368 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2369 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2371 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2373 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2375 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2376 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2378 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2381 * The (single-threaded) finalization code might have done
2382 * some copying/marking so we can only reset the GC thread's
2383 * worker data here instead of earlier when we joined the
2386 sgen_workers_reset_data ();
2388 if (objects_pinned) {
2389 sgen_optimize_pin_queue ();
2390 sgen_pinning_setup_section (nursery_section);
2393 /* walk the pin_queue, build up the fragment list of free memory, unmark
2394 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2397 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2398 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2399 if (!fragment_total)
2402 /* Clear TLABs for all threads */
2403 sgen_clear_tlabs ();
2405 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2407 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2408 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2410 if (consistency_check_at_minor_collection)
2411 sgen_check_major_refs ();
2413 major_collector.finish_nursery_collection ();
2415 TV_GETTIME (last_minor_collection_end_tv);
2416 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2419 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2421 /* prepare the pin queue for the next collection */
2422 sgen_finish_pinning ();
2423 if (fin_ready_list || critical_fin_list) {
2424 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2425 mono_gc_finalize_notify ();
2427 sgen_pin_stats_reset ();
2428 /* clear cemented hash */
2429 sgen_cement_clear_below_threshold ();
2431 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2433 remset.finish_minor_collection ();
2435 check_scan_starts ();
2437 binary_protocol_flush_buffers (FALSE);
2439 sgen_memgov_minor_collection_end ();
2441 /*objects are late pinned because of lack of memory, so a major is a good call*/
2442 needs_major = objects_pinned > 0;
2443 current_collection_generation = -1;
2446 MONO_GC_END (GENERATION_NURSERY);
2447 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
2449 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2450 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2456 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2459 * This is called on all objects in the nursery, including pinned ones, so we need
2460 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2462 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2466 scan_nursery_objects (ScanCopyContext ctx)
2468 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2469 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2473 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)
2478 /* FIXME: only use these values for the precise scan
2479 * note that to_space pointers should be excluded anyway...
2481 char *heap_start = NULL;
2482 char *heap_end = (char*)-1;
2483 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2484 GCRootReport root_report = { 0 };
2485 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2486 ScanThreadDataJobData *stdjd;
2487 ScanCopyContext ctx;
2489 if (concurrent_collection_in_progress) {
2490 /*This cleans up unused fragments */
2491 sgen_nursery_allocator_prepare_for_pinning ();
2493 if (do_concurrent_checks)
2494 check_nursery_is_clean ();
2496 /* The concurrent collector doesn't touch the nursery. */
2497 sgen_nursery_alloc_prepare_for_major ();
2504 /* Pinning depends on this */
2505 sgen_clear_nursery_fragments ();
2507 if (whole_heap_check_before_collection)
2508 sgen_check_whole_heap (finish_up_concurrent_mark);
2511 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2513 if (!sgen_collection_is_concurrent ())
2514 nursery_section->next_data = sgen_get_nursery_end ();
2515 /* we should also coalesce scanning from sections close to each other
2516 * and deal with pointers outside of the sections later.
2520 *major_collector.have_swept = FALSE;
2522 if (xdomain_checks) {
2523 sgen_clear_nursery_fragments ();
2524 sgen_check_for_xdomain_refs ();
2527 if (!concurrent_collection_in_progress) {
2528 /* Remsets are not useful for a major collection */
2529 remset.prepare_for_major_collection ();
2532 sgen_process_fin_stage_entries ();
2533 sgen_process_dislink_stage_entries ();
2536 sgen_init_pinning ();
2537 SGEN_LOG (6, "Collecting pinned addresses");
2538 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2540 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2541 if (major_collector.is_concurrent) {
2543 * The concurrent major collector cannot evict
2544 * yet, so we need to pin cemented objects to
2545 * not break some asserts.
2547 * FIXME: We could evict now!
2549 sgen_pin_cemented_objects ();
2552 if (!concurrent_collection_in_progress)
2553 sgen_cement_reset ();
2556 sgen_optimize_pin_queue ();
2559 * pin_queue now contains all candidate pointers, sorted and
2560 * uniqued. We must do two passes now to figure out which
2561 * objects are pinned.
2563 * The first is to find within the pin_queue the area for each
2564 * section. This requires that the pin_queue be sorted. We
2565 * also process the LOS objects and pinned chunks here.
2567 * The second, destructive, pass is to reduce the section
2568 * areas to pointers to the actually pinned objects.
2570 SGEN_LOG (6, "Pinning from sections");
2571 /* first pass for the sections */
2572 sgen_find_section_pin_queue_start_end (nursery_section);
2573 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2574 /* identify possible pointers to the insize of large objects */
2575 SGEN_LOG (6, "Pinning from large objects");
2576 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2578 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2579 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2581 #ifdef ENABLE_DTRACE
2582 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2583 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2584 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2588 if (sgen_los_object_is_pinned (bigobj->data)) {
2589 g_assert (finish_up_concurrent_mark);
2592 sgen_los_pin_object (bigobj->data);
2593 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2594 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2595 if (G_UNLIKELY (do_pin_stats))
2596 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2597 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));
2600 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2604 notify_gc_roots (&root_report);
2605 /* second pass for the sections */
2606 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2607 ctx.copy_func = NULL;
2608 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2611 * Concurrent mark never follows references into the nursery. In the start and
2612 * finish pauses we must scan live nursery objects, though.
2614 * In the finish pause we do this conservatively by scanning all nursery objects.
2615 * Previously we would only scan pinned objects here. We assumed that all objects
2616 * that were pinned during the nursery collection immediately preceding this finish
2617 * mark would be pinned again here. Due to the way we get the stack end for the GC
2618 * thread, however, that's not necessarily the case: we scan part of the stack used
2619 * by the GC itself, which changes constantly, so pinning isn't entirely
2622 * The split nursery also complicates things because non-pinned objects can survive
2623 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2625 * In the future we shouldn't do a preceding nursery collection at all and instead
2626 * do the finish pause with promotion from the nursery.
2628 * A further complication arises when we have late-pinned objects from the preceding
2629 * nursery collection. Those are the result of being out of memory when trying to
2630 * evacuate objects. They won't be found from the roots, so we just scan the whole
2633 * Non-concurrent mark evacuates from the nursery, so it's
2634 * sufficient to just scan pinned nursery objects.
2636 if (scan_whole_nursery || finish_up_concurrent_mark || (concurrent_collection_in_progress && sgen_minor_collector.is_split)) {
2637 scan_nursery_objects (ctx);
2639 pin_objects_in_nursery (ctx);
2640 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2641 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2644 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2645 if (old_next_pin_slot)
2646 *old_next_pin_slot = sgen_get_pinned_count ();
2649 time_major_pinning += TV_ELAPSED (atv, btv);
2650 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2651 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2653 major_collector.init_to_space ();
2656 * The concurrent collector doesn't move objects, neither on
2657 * the major heap nor in the nursery, so we can mark even
2658 * before pinning has finished. For the non-concurrent
2659 * collector we start the workers after pinning.
2661 if (start_concurrent_mark) {
2662 sgen_workers_start_all_workers ();
2663 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2666 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2667 main_gc_thread = mono_native_thread_self ();
2670 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2671 report_registered_roots ();
2673 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2675 /* registered roots, this includes static fields */
2676 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2677 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2678 scrrjd_normal->scan_func = current_object_ops.scan_object;
2679 scrrjd_normal->heap_start = heap_start;
2680 scrrjd_normal->heap_end = heap_end;
2681 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2682 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2684 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2685 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2686 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2687 scrrjd_wbarrier->heap_start = heap_start;
2688 scrrjd_wbarrier->heap_end = heap_end;
2689 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2690 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2693 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2696 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2697 stdjd->heap_start = heap_start;
2698 stdjd->heap_end = heap_end;
2699 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2702 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2705 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2707 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2708 report_finalizer_roots ();
2710 /* scan the list of objects ready for finalization */
2711 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2712 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2714 if (scan_mod_union) {
2715 g_assert (finish_up_concurrent_mark);
2717 /* Mod union card table */
2718 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2719 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2723 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2724 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2727 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2731 major_finish_copy_or_mark (void)
2733 if (!concurrent_collection_in_progress)
2737 * Prepare the pin queue for the next collection. Since pinning runs on the worker
2738 * threads we must wait for the jobs to finish before we can reset it.
2740 sgen_workers_wait_for_jobs_finished ();
2741 sgen_finish_pinning ();
2743 sgen_pin_stats_reset ();
2745 if (do_concurrent_checks)
2746 check_nursery_is_clean ();
2750 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2752 MONO_GC_BEGIN (GENERATION_OLD);
2753 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2755 current_collection_generation = GENERATION_OLD;
2756 #ifndef DISABLE_PERFCOUNTERS
2757 mono_perfcounters->gc_collections1++;
2760 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2763 g_assert (major_collector.is_concurrent);
2764 concurrent_collection_in_progress = TRUE;
2766 sgen_cement_concurrent_start ();
2768 current_object_ops = major_collector.major_concurrent_ops;
2770 current_object_ops = major_collector.major_ops;
2773 reset_pinned_from_failed_allocation ();
2775 sgen_memgov_major_collection_start ();
2777 //count_ref_nonref_objs ();
2778 //consistency_check ();
2780 check_scan_starts ();
2783 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2784 gc_stats.major_gc_count ++;
2786 if (major_collector.start_major_collection)
2787 major_collector.start_major_collection ();
2789 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent, FALSE, FALSE, FALSE);
2790 major_finish_copy_or_mark ();
2794 wait_for_workers_to_finish (void)
2796 while (!sgen_workers_all_done ())
2801 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union, gboolean scan_whole_nursery)
2803 ScannedObjectCounts counts;
2804 LOSObject *bigobj, *prevbo;
2810 if (concurrent_collection_in_progress) {
2811 sgen_workers_signal_start_nursery_collection_and_wait ();
2813 current_object_ops = major_collector.major_concurrent_ops;
2815 major_copy_or_mark_from_roots (NULL, FALSE, TRUE, scan_mod_union, scan_whole_nursery);
2817 sgen_workers_signal_finish_nursery_collection ();
2819 major_finish_copy_or_mark ();
2820 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2822 sgen_workers_join ();
2824 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2826 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2827 main_gc_thread = NULL;
2830 if (do_concurrent_checks)
2831 check_nursery_is_clean ();
2833 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2834 current_object_ops = major_collector.major_ops;
2838 * The workers have stopped so we need to finish gray queue
2839 * work that might result from finalization in the main GC
2840 * thread. Redirection must therefore be turned off.
2842 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2843 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2845 /* all the objects in the heap */
2846 finish_gray_stack (GENERATION_OLD, &gray_queue);
2848 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2850 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2853 * The (single-threaded) finalization code might have done
2854 * some copying/marking so we can only reset the GC thread's
2855 * worker data here instead of earlier when we joined the
2858 sgen_workers_reset_data ();
2860 if (objects_pinned) {
2861 g_assert (!concurrent_collection_in_progress);
2864 * This is slow, but we just OOM'd.
2866 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2867 * queue is laid out at this point.
2869 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2871 * We need to reestablish all pinned nursery objects in the pin queue
2872 * because they're needed for fragment creation. Unpinning happens by
2873 * walking the whole queue, so it's not necessary to reestablish where major
2874 * heap block pins are - all we care is that they're still in there
2877 sgen_optimize_pin_queue ();
2878 sgen_find_section_pin_queue_start_end (nursery_section);
2882 reset_heap_boundaries ();
2883 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2885 if (!concurrent_collection_in_progress) {
2886 /* walk the pin_queue, build up the fragment list of free memory, unmark
2887 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2890 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2893 /* prepare the pin queue for the next collection */
2894 sgen_finish_pinning ();
2896 /* Clear TLABs for all threads */
2897 sgen_clear_tlabs ();
2899 sgen_pin_stats_reset ();
2902 if (concurrent_collection_in_progress)
2903 sgen_cement_concurrent_finish ();
2904 sgen_cement_clear_below_threshold ();
2906 if (check_mark_bits_after_major_collection)
2907 sgen_check_heap_marked (concurrent_collection_in_progress);
2910 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2913 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2915 /* sweep the big objects list */
2917 for (bigobj = los_object_list; bigobj;) {
2918 g_assert (!object_is_pinned (bigobj->data));
2919 if (sgen_los_object_is_pinned (bigobj->data)) {
2920 sgen_los_unpin_object (bigobj->data);
2921 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2924 /* not referenced anywhere, so we can free it */
2926 prevbo->next = bigobj->next;
2928 los_object_list = bigobj->next;
2930 bigobj = bigobj->next;
2931 sgen_los_free_object (to_free);
2935 bigobj = bigobj->next;
2939 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2944 time_major_los_sweep += TV_ELAPSED (atv, btv);
2946 major_collector.sweep ();
2948 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2951 time_major_sweep += TV_ELAPSED (btv, atv);
2954 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2956 if (fin_ready_list || critical_fin_list) {
2957 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2958 mono_gc_finalize_notify ();
2961 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2963 sgen_memgov_major_collection_end ();
2964 current_collection_generation = -1;
2966 memset (&counts, 0, sizeof (ScannedObjectCounts));
2967 major_collector.finish_major_collection (&counts);
2969 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2971 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2972 if (concurrent_collection_in_progress)
2973 concurrent_collection_in_progress = FALSE;
2975 check_scan_starts ();
2977 binary_protocol_flush_buffers (FALSE);
2979 //consistency_check ();
2981 MONO_GC_END (GENERATION_OLD);
2982 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2986 major_do_collection (const char *reason)
2988 TV_DECLARE (time_start);
2989 TV_DECLARE (time_end);
2990 size_t old_next_pin_slot;
2992 if (disable_major_collections)
2995 if (major_collector.get_and_reset_num_major_objects_marked) {
2996 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2997 g_assert (!num_marked);
3000 /* world must be stopped already */
3001 TV_GETTIME (time_start);
3003 major_start_collection (FALSE, &old_next_pin_slot);
3004 major_finish_collection (reason, old_next_pin_slot, FALSE, FALSE);
3006 TV_GETTIME (time_end);
3007 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3009 /* FIXME: also report this to the user, preferably in gc-end. */
3010 if (major_collector.get_and_reset_num_major_objects_marked)
3011 major_collector.get_and_reset_num_major_objects_marked ();
3013 return bytes_pinned_from_failed_allocation > 0;
3017 major_start_concurrent_collection (const char *reason)
3019 TV_DECLARE (time_start);
3020 TV_DECLARE (time_end);
3021 long long num_objects_marked;
3023 if (disable_major_collections)
3026 TV_GETTIME (time_start);
3027 SGEN_TV_GETTIME (time_major_conc_collection_start);
3029 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3030 g_assert (num_objects_marked == 0);
3032 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3033 binary_protocol_concurrent_start ();
3035 // FIXME: store reason and pass it when finishing
3036 major_start_collection (TRUE, NULL);
3038 gray_queue_redirect (&gray_queue);
3040 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3041 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3043 TV_GETTIME (time_end);
3044 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3046 current_collection_generation = -1;
3050 * Returns whether the major collection has finished.
3053 major_should_finish_concurrent_collection (void)
3055 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
3056 return sgen_workers_all_done ();
3060 major_update_concurrent_collection (void)
3062 TV_DECLARE (total_start);
3063 TV_DECLARE (total_end);
3065 TV_GETTIME (total_start);
3067 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3068 binary_protocol_concurrent_update ();
3070 major_collector.update_cardtable_mod_union ();
3071 sgen_los_update_cardtable_mod_union ();
3073 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3075 TV_GETTIME (total_end);
3076 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3080 major_finish_concurrent_collection (void)
3082 TV_DECLARE (total_start);
3083 TV_DECLARE (total_end);
3084 gboolean late_pinned;
3085 SgenGrayQueue unpin_queue;
3086 memset (&unpin_queue, 0, sizeof (unpin_queue));
3088 TV_GETTIME (total_start);
3090 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3091 binary_protocol_concurrent_finish ();
3094 * The major collector can add global remsets which are processed in the finishing
3095 * nursery collection, below. That implies that the workers must have finished
3096 * marking before the nursery collection is allowed to run, otherwise we might miss
3099 wait_for_workers_to_finish ();
3101 SGEN_TV_GETTIME (time_major_conc_collection_end);
3102 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3104 major_collector.update_cardtable_mod_union ();
3105 sgen_los_update_cardtable_mod_union ();
3107 late_pinned = collect_nursery (&unpin_queue, TRUE);
3109 if (mod_union_consistency_check)
3110 sgen_check_mod_union_consistency ();
3112 current_collection_generation = GENERATION_OLD;
3113 major_finish_collection ("finishing", -1, TRUE, late_pinned);
3115 if (whole_heap_check_before_collection)
3116 sgen_check_whole_heap (FALSE);
3118 unpin_objects_from_queue (&unpin_queue);
3119 sgen_gray_object_queue_deinit (&unpin_queue);
3121 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3123 TV_GETTIME (total_end);
3124 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3126 current_collection_generation = -1;
3130 * Ensure an allocation request for @size will succeed by freeing enough memory.
3132 * LOCKING: The GC lock MUST be held.
3135 sgen_ensure_free_space (size_t size)
3137 int generation_to_collect = -1;
3138 const char *reason = NULL;
3141 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3142 if (sgen_need_major_collection (size)) {
3143 reason = "LOS overflow";
3144 generation_to_collect = GENERATION_OLD;
3147 if (degraded_mode) {
3148 if (sgen_need_major_collection (size)) {
3149 reason = "Degraded mode overflow";
3150 generation_to_collect = GENERATION_OLD;
3152 } else if (sgen_need_major_collection (size)) {
3153 reason = "Minor allowance";
3154 generation_to_collect = GENERATION_OLD;
3156 generation_to_collect = GENERATION_NURSERY;
3157 reason = "Nursery full";
3161 if (generation_to_collect == -1) {
3162 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3163 generation_to_collect = GENERATION_OLD;
3164 reason = "Finish concurrent collection";
3168 if (generation_to_collect == -1)
3170 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3174 * LOCKING: Assumes the GC lock is held.
3177 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3179 TV_DECLARE (gc_start);
3180 TV_DECLARE (gc_end);
3181 TV_DECLARE (gc_total_start);
3182 TV_DECLARE (gc_total_end);
3183 GGTimingInfo infos [2];
3184 int overflow_generation_to_collect = -1;
3185 int oldest_generation_collected = generation_to_collect;
3186 const char *overflow_reason = NULL;
3188 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3190 binary_protocol_collection_force (generation_to_collect);
3192 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3194 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3196 TV_GETTIME (gc_start);
3198 sgen_stop_world (generation_to_collect);
3200 TV_GETTIME (gc_total_start);
3202 if (concurrent_collection_in_progress) {
3204 * We update the concurrent collection. If it finished, we're done. If
3205 * not, and we've been asked to do a nursery collection, we do that.
3207 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3210 major_finish_concurrent_collection ();
3211 oldest_generation_collected = GENERATION_OLD;
3213 sgen_workers_signal_start_nursery_collection_and_wait ();
3215 major_update_concurrent_collection ();
3216 if (generation_to_collect == GENERATION_NURSERY)
3217 collect_nursery (NULL, FALSE);
3219 sgen_workers_signal_finish_nursery_collection ();
3226 * If we've been asked to do a major collection, and the major collector wants to
3227 * run synchronously (to evacuate), we set the flag to do that.
3229 if (generation_to_collect == GENERATION_OLD &&
3230 allow_synchronous_major &&
3231 major_collector.want_synchronous_collection &&
3232 *major_collector.want_synchronous_collection) {
3233 wait_to_finish = TRUE;
3236 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3239 * There's no concurrent collection in progress. Collect the generation we're asked
3240 * to collect. If the major collector is concurrent and we're not forced to wait,
3241 * start a concurrent collection.
3243 // FIXME: extract overflow reason
3244 if (generation_to_collect == GENERATION_NURSERY) {
3245 if (collect_nursery (NULL, FALSE)) {
3246 overflow_generation_to_collect = GENERATION_OLD;
3247 overflow_reason = "Minor overflow";
3250 if (major_collector.is_concurrent && !wait_to_finish) {
3251 collect_nursery (NULL, FALSE);
3252 major_start_concurrent_collection (reason);
3253 // FIXME: set infos[0] properly
3257 if (major_do_collection (reason)) {
3258 overflow_generation_to_collect = GENERATION_NURSERY;
3259 overflow_reason = "Excessive pinning";
3263 TV_GETTIME (gc_end);
3265 memset (infos, 0, sizeof (infos));
3266 infos [0].generation = generation_to_collect;
3267 infos [0].reason = reason;
3268 infos [0].is_overflow = FALSE;
3269 infos [1].generation = -1;
3270 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3272 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3274 if (overflow_generation_to_collect != -1) {
3276 * We need to do an overflow collection, either because we ran out of memory
3277 * or the nursery is fully pinned.
3280 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3281 infos [1].generation = overflow_generation_to_collect;
3282 infos [1].reason = overflow_reason;
3283 infos [1].is_overflow = TRUE;
3284 infos [1].total_time = gc_end;
3286 if (overflow_generation_to_collect == GENERATION_NURSERY)
3287 collect_nursery (NULL, FALSE);
3289 major_do_collection (overflow_reason);
3291 TV_GETTIME (gc_end);
3292 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3294 /* keep events symmetric */
3295 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3297 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3300 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3302 /* this also sets the proper pointers for the next allocation */
3303 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3304 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3305 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3306 sgen_dump_pin_queue ();
3311 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3313 TV_GETTIME (gc_total_end);
3314 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3316 sgen_restart_world (oldest_generation_collected, infos);
3318 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3322 * ######################################################################
3323 * ######## Memory allocation from the OS
3324 * ######################################################################
3325 * This section of code deals with getting memory from the OS and
3326 * allocating memory for GC-internal data structures.
3327 * Internal memory can be handled with a freelist for small objects.
3333 G_GNUC_UNUSED static void
3334 report_internal_mem_usage (void)
3336 printf ("Internal memory usage:\n");
3337 sgen_report_internal_mem_usage ();
3338 printf ("Pinned memory usage:\n");
3339 major_collector.report_pinned_memory_usage ();
3343 * ######################################################################
3344 * ######## Finalization support
3345 * ######################################################################
3348 static inline gboolean
3349 sgen_major_is_object_alive (void *object)
3353 /* Oldgen objects can be pinned and forwarded too */
3354 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3358 * FIXME: major_collector.is_object_live() also calculates the
3359 * size. Avoid the double calculation.
3361 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3362 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3363 return sgen_los_object_is_pinned (object);
3365 return major_collector.is_object_live (object);
3369 * If the object has been forwarded it means it's still referenced from a root.
3370 * If it is pinned it's still alive as well.
3371 * A LOS object is only alive if we have pinned it.
3372 * Return TRUE if @obj is ready to be finalized.
3374 static inline gboolean
3375 sgen_is_object_alive (void *object)
3377 if (ptr_in_nursery (object))
3378 return sgen_nursery_is_object_alive (object);
3380 return sgen_major_is_object_alive (object);
3384 * This function returns true if @object is either alive or it belongs to the old gen
3385 * and we're currently doing a minor collection.
3388 sgen_is_object_alive_for_current_gen (char *object)
3390 if (ptr_in_nursery (object))
3391 return sgen_nursery_is_object_alive (object);
3393 if (current_collection_generation == GENERATION_NURSERY)
3396 return sgen_major_is_object_alive (object);
3400 * This function returns true if @object is either alive and belongs to the
3401 * current collection - major collections are full heap, so old gen objects
3402 * are never alive during a minor collection.
3405 sgen_is_object_alive_and_on_current_collection (char *object)
3407 if (ptr_in_nursery (object))
3408 return sgen_nursery_is_object_alive (object);
3410 if (current_collection_generation == GENERATION_NURSERY)
3413 return sgen_major_is_object_alive (object);
3418 sgen_gc_is_object_ready_for_finalization (void *object)
3420 return !sgen_is_object_alive (object);
3424 has_critical_finalizer (MonoObject *obj)
3428 if (!mono_defaults.critical_finalizer_object)
3431 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3433 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3437 is_finalization_aware (MonoObject *obj)
3439 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3440 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3444 sgen_queue_finalization_entry (MonoObject *obj)
3446 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3447 gboolean critical = has_critical_finalizer (obj);
3448 entry->object = obj;
3450 entry->next = critical_fin_list;
3451 critical_fin_list = entry;
3453 entry->next = fin_ready_list;
3454 fin_ready_list = entry;
3457 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3458 fin_callbacks.object_queued_for_finalization (obj);
3460 #ifdef ENABLE_DTRACE
3461 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3462 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3463 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3464 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3465 vt->klass->name_space, vt->klass->name, gen, critical);
3471 sgen_object_is_live (void *obj)
3473 return sgen_is_object_alive_and_on_current_collection (obj);
3476 /* LOCKING: requires that the GC lock is held */
3478 null_ephemerons_for_domain (MonoDomain *domain)
3480 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3483 MonoObject *object = (MonoObject*)current->array;
3486 SGEN_ASSERT (0, object->vtable, "Can't have objects without vtables.");
3488 if (object && object->vtable->domain == domain) {
3489 EphemeronLinkNode *tmp = current;
3492 prev->next = current->next;
3494 ephemeron_list = current->next;
3496 current = current->next;
3497 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3500 current = current->next;
3505 /* LOCKING: requires that the GC lock is held */
3507 clear_unreachable_ephemerons (ScanCopyContext ctx)
3509 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3510 GrayQueue *queue = ctx.queue;
3511 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3513 Ephemeron *cur, *array_end;
3517 char *object = current->array;
3519 if (!sgen_is_object_alive_for_current_gen (object)) {
3520 EphemeronLinkNode *tmp = current;
3522 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3525 prev->next = current->next;
3527 ephemeron_list = current->next;
3529 current = current->next;
3530 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3535 copy_func ((void**)&object, queue);
3536 current->array = object;
3538 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3540 array = (MonoArray*)object;
3541 cur = mono_array_addr (array, Ephemeron, 0);
3542 array_end = cur + mono_array_length_fast (array);
3543 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3545 for (; cur < array_end; ++cur) {
3546 char *key = (char*)cur->key;
3548 if (!key || key == tombstone)
3551 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3552 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3553 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3555 if (!sgen_is_object_alive_for_current_gen (key)) {
3556 cur->key = tombstone;
3562 current = current->next;
3567 LOCKING: requires that the GC lock is held
3569 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3572 mark_ephemerons_in_range (ScanCopyContext ctx)
3574 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3575 GrayQueue *queue = ctx.queue;
3576 int nothing_marked = 1;
3577 EphemeronLinkNode *current = ephemeron_list;
3579 Ephemeron *cur, *array_end;
3582 for (current = ephemeron_list; current; current = current->next) {
3583 char *object = current->array;
3584 SGEN_LOG (5, "Ephemeron array at %p", object);
3586 /*It has to be alive*/
3587 if (!sgen_is_object_alive_for_current_gen (object)) {
3588 SGEN_LOG (5, "\tnot reachable");
3592 copy_func ((void**)&object, queue);
3594 array = (MonoArray*)object;
3595 cur = mono_array_addr (array, Ephemeron, 0);
3596 array_end = cur + mono_array_length_fast (array);
3597 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3599 for (; cur < array_end; ++cur) {
3600 char *key = cur->key;
3602 if (!key || key == tombstone)
3605 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3606 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3607 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3609 if (sgen_is_object_alive_for_current_gen (key)) {
3610 char *value = cur->value;
3612 copy_func ((void**)&cur->key, queue);
3614 if (!sgen_is_object_alive_for_current_gen (value))
3616 copy_func ((void**)&cur->value, queue);
3622 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3623 return nothing_marked;
3627 mono_gc_invoke_finalizers (void)
3629 FinalizeReadyEntry *entry = NULL;
3630 gboolean entry_is_critical = FALSE;
3633 /* FIXME: batch to reduce lock contention */
3634 while (fin_ready_list || critical_fin_list) {
3638 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3640 /* We have finalized entry in the last
3641 interation, now we need to remove it from
3644 *list = entry->next;
3646 FinalizeReadyEntry *e = *list;
3647 while (e->next != entry)
3649 e->next = entry->next;
3651 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3655 /* Now look for the first non-null entry. */
3656 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3659 entry_is_critical = FALSE;
3661 entry_is_critical = TRUE;
3662 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3667 g_assert (entry->object);
3668 num_ready_finalizers--;
3669 obj = entry->object;
3670 entry->object = NULL;
3671 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3679 g_assert (entry->object == NULL);
3681 /* the object is on the stack so it is pinned */
3682 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3683 mono_gc_run_finalize (obj, NULL);
3690 mono_gc_pending_finalizers (void)
3692 return fin_ready_list || critical_fin_list;
3696 * ######################################################################
3697 * ######## registered roots support
3698 * ######################################################################
3702 * We do not coalesce roots.
3705 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3707 RootRecord new_root;
3710 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3711 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3712 /* we allow changing the size and the descriptor (for thread statics etc) */
3714 size_t old_size = root->end_root - start;
3715 root->end_root = start + size;
3716 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3717 ((root->root_desc == 0) && (descr == NULL)));
3718 root->root_desc = (mword)descr;
3720 roots_size -= old_size;
3726 new_root.end_root = start + size;
3727 new_root.root_desc = (mword)descr;
3729 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3732 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);
3739 mono_gc_register_root (char *start, size_t size, void *descr)
3741 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3745 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3747 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3751 mono_gc_deregister_root (char* addr)
3757 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3758 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3759 roots_size -= (root.end_root - addr);
3765 * ######################################################################
3766 * ######## Thread handling (stop/start code)
3767 * ######################################################################
3770 unsigned int sgen_global_stop_count = 0;
3773 sgen_get_current_collection_generation (void)
3775 return current_collection_generation;
3779 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3781 gc_callbacks = *callbacks;
3785 mono_gc_get_gc_callbacks ()
3787 return &gc_callbacks;
3790 /* Variables holding start/end nursery so it won't have to be passed at every call */
3791 static void *scan_area_arg_start, *scan_area_arg_end;
3794 mono_gc_conservatively_scan_area (void *start, void *end)
3796 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3800 mono_gc_scan_object (void *obj, void *gc_data)
3802 UserCopyOrMarkData *data = gc_data;
3803 current_object_ops.copy_or_mark_object (&obj, data->queue);
3808 * Mark from thread stacks and registers.
3811 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3813 SgenThreadInfo *info;
3815 scan_area_arg_start = start_nursery;
3816 scan_area_arg_end = end_nursery;
3818 FOREACH_THREAD (info) {
3820 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);
3823 if (info->gc_disabled) {
3824 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);
3827 if (!mono_thread_info_is_live (info)) {
3828 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);
3831 g_assert (info->suspend_done);
3832 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 ());
3833 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3834 UserCopyOrMarkData data = { NULL, queue };
3835 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3836 } else if (!precise) {
3837 if (!conservative_stack_mark) {
3838 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3839 conservative_stack_mark = TRUE;
3841 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3846 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3847 start_nursery, end_nursery, PIN_TYPE_STACK);
3849 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3850 start_nursery, end_nursery, PIN_TYPE_STACK);
3853 } END_FOREACH_THREAD
3857 ptr_on_stack (void *ptr)
3859 gpointer stack_start = &stack_start;
3860 SgenThreadInfo *info = mono_thread_info_current ();
3862 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3868 sgen_thread_register (SgenThreadInfo* info, void *addr)
3871 guint8 *staddr = NULL;
3873 #ifndef HAVE_KW_THREAD
3874 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3876 g_assert (!mono_native_tls_get_value (thread_info_key));
3877 mono_native_tls_set_value (thread_info_key, info);
3879 sgen_thread_info = info;
3882 #ifdef SGEN_POSIX_STW
3883 info->stop_count = -1;
3887 info->stack_start = NULL;
3888 info->stopped_ip = NULL;
3889 info->stopped_domain = NULL;
3891 memset (&info->ctx, 0, sizeof (MonoContext));
3893 memset (&info->regs, 0, sizeof (info->regs));
3896 sgen_init_tlab_info (info);
3898 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3900 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3901 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3904 info->stack_start_limit = staddr;
3906 info->stack_end = staddr + stsize;
3908 gsize stack_bottom = (gsize)addr;
3909 stack_bottom += 4095;
3910 stack_bottom &= ~4095;
3911 info->stack_end = (char*)stack_bottom;
3914 #ifdef HAVE_KW_THREAD
3915 stack_end = info->stack_end;
3918 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3920 if (gc_callbacks.thread_attach_func)
3921 info->runtime_data = gc_callbacks.thread_attach_func ();
3926 sgen_thread_detach (SgenThreadInfo *p)
3928 /* If a delegate is passed to native code and invoked on a thread we dont
3929 * know about, the jit will register it with mono_jit_thread_attach, but
3930 * we have no way of knowing when that thread goes away. SGen has a TSD
3931 * so we assume that if the domain is still registered, we can detach
3934 if (mono_domain_get ())
3935 mono_thread_detach_internal (mono_thread_internal_current ());
3939 sgen_thread_unregister (SgenThreadInfo *p)
3941 MonoNativeThreadId tid;
3943 tid = mono_thread_info_get_tid (p);
3944 binary_protocol_thread_unregister ((gpointer)tid);
3945 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3947 #ifndef HAVE_KW_THREAD
3948 mono_native_tls_set_value (thread_info_key, NULL);
3950 sgen_thread_info = NULL;
3953 if (p->info.runtime_thread)
3954 mono_threads_add_joinable_thread ((gpointer)tid);
3956 if (gc_callbacks.thread_detach_func) {
3957 gc_callbacks.thread_detach_func (p->runtime_data);
3958 p->runtime_data = NULL;
3964 sgen_thread_attach (SgenThreadInfo *info)
3967 /*this is odd, can we get attached before the gc is inited?*/
3971 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3972 info->runtime_data = gc_callbacks.thread_attach_func ();
3975 mono_gc_register_thread (void *baseptr)
3977 return mono_thread_info_attach (baseptr) != NULL;
3981 * mono_gc_set_stack_end:
3983 * Set the end of the current threads stack to STACK_END. The stack space between
3984 * STACK_END and the real end of the threads stack will not be scanned during collections.
3987 mono_gc_set_stack_end (void *stack_end)
3989 SgenThreadInfo *info;
3992 info = mono_thread_info_current ();
3994 g_assert (stack_end < info->stack_end);
3995 info->stack_end = stack_end;
4000 #if USE_PTHREAD_INTERCEPT
4004 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
4006 return pthread_create (new_thread, attr, start_routine, arg);
4010 mono_gc_pthread_join (pthread_t thread, void **retval)
4012 return pthread_join (thread, retval);
4016 mono_gc_pthread_detach (pthread_t thread)
4018 return pthread_detach (thread);
4022 mono_gc_pthread_exit (void *retval)
4024 mono_thread_info_detach ();
4025 pthread_exit (retval);
4026 g_assert_not_reached ();
4029 #endif /* USE_PTHREAD_INTERCEPT */
4032 * ######################################################################
4033 * ######## Write barriers
4034 * ######################################################################
4038 * Note: the write barriers first do the needed GC work and then do the actual store:
4039 * this way the value is visible to the conservative GC scan after the write barrier
4040 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
4041 * the conservative scan, otherwise by the remembered set scan.
4044 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
4046 HEAVY_STAT (++stat_wbarrier_set_field);
4047 if (ptr_in_nursery (field_ptr)) {
4048 *(void**)field_ptr = value;
4051 SGEN_LOG (8, "Adding remset at %p", field_ptr);
4053 binary_protocol_wbarrier (field_ptr, value, value->vtable);
4055 remset.wbarrier_set_field (obj, field_ptr, value);
4059 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
4061 HEAVY_STAT (++stat_wbarrier_set_arrayref);
4062 if (ptr_in_nursery (slot_ptr)) {
4063 *(void**)slot_ptr = value;
4066 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
4068 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
4070 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4074 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4076 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4077 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4078 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4079 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4083 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4084 if (binary_protocol_is_heavy_enabled ()) {
4086 for (i = 0; i < count; ++i) {
4087 gpointer dest = (gpointer*)dest_ptr + i;
4088 gpointer obj = *((gpointer*)src_ptr + i);
4090 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4095 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4098 static char *found_obj;
4101 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4103 char *ptr = user_data;
4105 if (ptr >= obj && ptr < obj + size) {
4106 g_assert (!found_obj);
4111 /* for use in the debugger */
4112 char* find_object_for_ptr (char *ptr);
4114 find_object_for_ptr (char *ptr)
4116 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4118 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4119 find_object_for_ptr_callback, ptr, TRUE);
4125 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4130 * Very inefficient, but this is debugging code, supposed to
4131 * be called from gdb, so we don't care.
4134 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4139 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4143 HEAVY_STAT (++stat_wbarrier_generic_store);
4145 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4146 /* FIXME: ptr_in_heap must be called with the GC lock held */
4147 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4148 char *start = find_object_for_ptr (ptr);
4149 MonoObject *value = *(MonoObject**)ptr;
4153 MonoObject *obj = (MonoObject*)start;
4154 if (obj->vtable->domain != value->vtable->domain)
4155 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4161 obj = *(gpointer*)ptr;
4163 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4165 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4166 SGEN_LOG (8, "Skipping remset at %p", ptr);
4171 * We need to record old->old pointer locations for the
4172 * concurrent collector.
4174 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4175 SGEN_LOG (8, "Skipping remset at %p", ptr);
4179 SGEN_LOG (8, "Adding remset at %p", ptr);
4181 remset.wbarrier_generic_nostore (ptr);
4185 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4187 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4188 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4189 if (ptr_in_nursery (value))
4190 mono_gc_wbarrier_generic_nostore (ptr);
4191 sgen_dummy_use (value);
4194 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4195 * as an atomic operation with release semantics.
4198 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4200 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4202 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4204 InterlockedWritePointer (ptr, value);
4206 if (ptr_in_nursery (value))
4207 mono_gc_wbarrier_generic_nostore (ptr);
4209 sgen_dummy_use (value);
4212 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4214 mword *dest = _dest;
4219 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4221 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4224 size -= SIZEOF_VOID_P;
4229 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4231 #define HANDLE_PTR(ptr,obj) do { \
4232 gpointer o = *(gpointer*)(ptr); \
4234 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4235 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4240 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4242 #define SCAN_OBJECT_NOVTABLE
4243 #include "sgen-scan-object.h"
4248 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4250 HEAVY_STAT (++stat_wbarrier_value_copy);
4251 g_assert (klass->valuetype);
4253 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4255 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4256 size_t element_size = mono_class_value_size (klass, NULL);
4257 size_t size = count * element_size;
4258 mono_gc_memmove_atomic (dest, src, size);
4262 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4263 if (binary_protocol_is_heavy_enabled ()) {
4264 size_t element_size = mono_class_value_size (klass, NULL);
4266 for (i = 0; i < count; ++i) {
4267 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4268 (char*)src + i * element_size - sizeof (MonoObject),
4269 (mword) klass->gc_descr);
4274 remset.wbarrier_value_copy (dest, src, count, klass);
4278 * mono_gc_wbarrier_object_copy:
4280 * Write barrier to call when obj is the result of a clone or copy of an object.
4283 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4287 HEAVY_STAT (++stat_wbarrier_object_copy);
4289 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4290 size = mono_object_class (obj)->instance_size;
4291 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4292 size - sizeof (MonoObject));
4296 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4297 if (binary_protocol_is_heavy_enabled ())
4298 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4301 remset.wbarrier_object_copy (obj, src);
4306 * ######################################################################
4307 * ######## Other mono public interface functions.
4308 * ######################################################################
4311 #define REFS_SIZE 128
4314 MonoGCReferences callback;
4318 MonoObject *refs [REFS_SIZE];
4319 uintptr_t offsets [REFS_SIZE];
4323 #define HANDLE_PTR(ptr,obj) do { \
4325 if (hwi->count == REFS_SIZE) { \
4326 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4330 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4331 hwi->refs [hwi->count++] = *(ptr); \
4336 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4338 mword desc = sgen_obj_get_descriptor (start);
4340 #include "sgen-scan-object.h"
4344 walk_references (char *start, size_t size, void *data)
4346 HeapWalkInfo *hwi = data;
4349 collect_references (hwi, start, size);
4350 if (hwi->count || !hwi->called)
4351 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4355 * mono_gc_walk_heap:
4356 * @flags: flags for future use
4357 * @callback: a function pointer called for each object in the heap
4358 * @data: a user data pointer that is passed to callback
4360 * This function can be used to iterate over all the live objects in the heap:
4361 * for each object, @callback is invoked, providing info about the object's
4362 * location in memory, its class, its size and the objects it references.
4363 * For each referenced object it's offset from the object address is
4364 * reported in the offsets array.
4365 * The object references may be buffered, so the callback may be invoked
4366 * multiple times for the same object: in all but the first call, the size
4367 * argument will be zero.
4368 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4369 * profiler event handler.
4371 * Returns: a non-zero value if the GC doesn't support heap walking
4374 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4379 hwi.callback = callback;
4382 sgen_clear_nursery_fragments ();
4383 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4385 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4386 sgen_los_iterate_objects (walk_references, &hwi);
4392 mono_gc_collect (int generation)
4397 sgen_perform_collection (0, generation, "user request", TRUE);
4402 mono_gc_max_generation (void)
4408 mono_gc_collection_count (int generation)
4410 if (generation == 0)
4411 return gc_stats.minor_gc_count;
4412 return gc_stats.major_gc_count;
4416 mono_gc_get_used_size (void)
4420 tot = los_memory_usage;
4421 tot += nursery_section->next_data - nursery_section->data;
4422 tot += major_collector.get_used_size ();
4423 /* FIXME: account for pinned objects */
4429 mono_gc_get_los_limit (void)
4431 return MAX_SMALL_OBJ_SIZE;
4435 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4437 mono_unichar2 *new_end = str->chars + new_length;
4439 /* zero the discarded string. This null-delimits the string and allows
4440 * the space to be reclaimed by SGen. */
4442 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4443 CHECK_CANARY_FOR_OBJECT (str);
4444 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4445 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4447 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4450 str->length = new_length;
4454 mono_gc_user_markers_supported (void)
4460 mono_object_is_alive (MonoObject* o)
4466 mono_gc_get_generation (MonoObject *obj)
4468 if (ptr_in_nursery (obj))
4474 mono_gc_enable_events (void)
4479 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4481 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4485 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4487 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4491 mono_gc_weak_link_get (void **link_addr)
4493 void * volatile *link_addr_volatile;
4497 link_addr_volatile = link_addr;
4498 ptr = (void*)*link_addr_volatile;
4500 * At this point we have a hidden pointer. If the GC runs
4501 * here, it will not recognize the hidden pointer as a
4502 * reference, and if the object behind it is not referenced
4503 * elsewhere, it will be freed. Once the world is restarted
4504 * we reveal the pointer, giving us a pointer to a freed
4505 * object. To make sure we don't return it, we load the
4506 * hidden pointer again. If it's still the same, we can be
4507 * sure the object reference is valid.
4510 obj = (MonoObject*) REVEAL_POINTER (ptr);
4514 mono_memory_barrier ();
4517 * During the second bridge processing step the world is
4518 * running again. That step processes all weak links once
4519 * more to null those that refer to dead objects. Before that
4520 * is completed, those links must not be followed, so we
4521 * conservatively wait for bridge processing when any weak
4522 * link is dereferenced.
4524 if (G_UNLIKELY (bridge_processing_in_progress))
4525 mono_gc_wait_for_bridge_processing ();
4527 if ((void*)*link_addr_volatile != ptr)
4534 mono_gc_ephemeron_array_add (MonoObject *obj)
4536 EphemeronLinkNode *node;
4540 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4545 node->array = (char*)obj;
4546 node->next = ephemeron_list;
4547 ephemeron_list = node;
4549 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4556 mono_gc_set_allow_synchronous_major (gboolean flag)
4558 if (!major_collector.is_concurrent)
4561 allow_synchronous_major = flag;
4566 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4570 result = func (data);
4571 UNLOCK_INTERRUPTION;
4576 mono_gc_is_gc_thread (void)
4580 result = mono_thread_info_current () != NULL;
4586 is_critical_method (MonoMethod *method)
4588 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4592 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4596 va_start (ap, description_format);
4598 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4599 vfprintf (stderr, description_format, ap);
4601 fprintf (stderr, " - %s", fallback);
4602 fprintf (stderr, "\n");
4608 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4611 double val = strtod (opt, &endptr);
4612 if (endptr == opt) {
4613 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4616 else if (val < min || val > max) {
4617 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4625 thread_in_critical_region (SgenThreadInfo *info)
4627 return info->in_critical_region;
4631 mono_gc_base_init (void)
4633 MonoThreadInfoCallbacks cb;
4636 char *major_collector_opt = NULL;
4637 char *minor_collector_opt = NULL;
4638 size_t max_heap = 0;
4639 size_t soft_limit = 0;
4642 gboolean debug_print_allowance = FALSE;
4643 double allowance_ratio = 0, save_target = 0;
4644 gboolean cement_enabled = TRUE;
4646 mono_counters_init ();
4649 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4652 /* already inited */
4655 /* being inited by another thread */
4659 /* we will init it */
4662 g_assert_not_reached ();
4664 } while (result != 0);
4666 SGEN_TV_GETTIME (sgen_init_timestamp);
4668 LOCK_INIT (gc_mutex);
4670 pagesize = mono_pagesize ();
4671 gc_debug_file = stderr;
4673 cb.thread_register = sgen_thread_register;
4674 cb.thread_detach = sgen_thread_detach;
4675 cb.thread_unregister = sgen_thread_unregister;
4676 cb.thread_attach = sgen_thread_attach;
4677 cb.mono_method_is_critical = (gpointer)is_critical_method;
4678 cb.mono_thread_in_critical_region = thread_in_critical_region;
4680 cb.thread_exit = mono_gc_pthread_exit;
4681 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4684 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4686 LOCK_INIT (sgen_interruption_mutex);
4688 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4689 opts = g_strsplit (env, ",", -1);
4690 for (ptr = opts; *ptr; ++ptr) {
4692 if (g_str_has_prefix (opt, "major=")) {
4693 opt = strchr (opt, '=') + 1;
4694 major_collector_opt = g_strdup (opt);
4695 } else if (g_str_has_prefix (opt, "minor=")) {
4696 opt = strchr (opt, '=') + 1;
4697 minor_collector_opt = g_strdup (opt);
4705 sgen_init_internal_allocator ();
4706 sgen_init_nursery_allocator ();
4707 sgen_init_fin_weak_hash ();
4709 sgen_init_hash_table ();
4710 sgen_init_descriptors ();
4711 sgen_init_gray_queues ();
4713 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4714 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4715 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4716 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4718 #ifndef HAVE_KW_THREAD
4719 mono_native_tls_alloc (&thread_info_key, NULL);
4720 #if defined(__APPLE__) || defined (HOST_WIN32)
4722 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4723 * where the two are the same.
4725 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4729 int tls_offset = -1;
4730 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4731 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4736 * This needs to happen before any internal allocations because
4737 * it inits the small id which is required for hazard pointer
4742 mono_thread_info_attach (&dummy);
4744 if (!minor_collector_opt) {
4745 sgen_simple_nursery_init (&sgen_minor_collector);
4747 if (!strcmp (minor_collector_opt, "simple")) {
4749 sgen_simple_nursery_init (&sgen_minor_collector);
4750 } else if (!strcmp (minor_collector_opt, "split")) {
4751 sgen_split_nursery_init (&sgen_minor_collector);
4753 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4754 goto use_simple_nursery;
4758 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4759 use_marksweep_major:
4760 sgen_marksweep_init (&major_collector);
4761 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4762 sgen_marksweep_conc_init (&major_collector);
4764 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4765 goto use_marksweep_major;
4768 ///* Keep this the default for now */
4769 /* Precise marking is broken on all supported targets. Disable until fixed. */
4770 conservative_stack_mark = TRUE;
4772 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4775 gboolean usage_printed = FALSE;
4777 for (ptr = opts; *ptr; ++ptr) {
4779 if (!strcmp (opt, ""))
4781 if (g_str_has_prefix (opt, "major="))
4783 if (g_str_has_prefix (opt, "minor="))
4785 if (g_str_has_prefix (opt, "max-heap-size=")) {
4786 size_t max_heap_candidate = 0;
4787 opt = strchr (opt, '=') + 1;
4788 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4789 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4790 if (max_heap != max_heap_candidate)
4791 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4793 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4797 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4798 opt = strchr (opt, '=') + 1;
4799 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4800 if (soft_limit <= 0) {
4801 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4805 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4809 if (g_str_has_prefix (opt, "stack-mark=")) {
4810 opt = strchr (opt, '=') + 1;
4811 if (!strcmp (opt, "precise")) {
4812 conservative_stack_mark = FALSE;
4813 } else if (!strcmp (opt, "conservative")) {
4814 conservative_stack_mark = TRUE;
4816 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4817 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4821 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4822 opt = strchr (opt, '=') + 1;
4823 sgen_set_bridge_implementation (opt);
4826 if (g_str_has_prefix (opt, "toggleref-test")) {
4827 sgen_register_test_toggleref_callback ();
4832 if (g_str_has_prefix (opt, "nursery-size=")) {
4834 opt = strchr (opt, '=') + 1;
4835 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4836 #ifdef SGEN_ALIGN_NURSERY
4837 if ((val & (val - 1))) {
4838 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4842 if (val < SGEN_MAX_NURSERY_WASTE) {
4843 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4844 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4848 sgen_nursery_size = val;
4849 sgen_nursery_bits = 0;
4850 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4853 sgen_nursery_size = val;
4856 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4862 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4864 opt = strchr (opt, '=') + 1;
4865 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4866 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4871 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4873 opt = strchr (opt, '=') + 1;
4874 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4875 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4876 allowance_ratio = val;
4880 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4881 if (!major_collector.is_concurrent) {
4882 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4886 opt = strchr (opt, '=') + 1;
4888 if (!strcmp (opt, "yes")) {
4889 allow_synchronous_major = TRUE;
4890 } else if (!strcmp (opt, "no")) {
4891 allow_synchronous_major = FALSE;
4893 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4898 if (!strcmp (opt, "cementing")) {
4899 cement_enabled = TRUE;
4902 if (!strcmp (opt, "no-cementing")) {
4903 cement_enabled = FALSE;
4907 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4910 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4913 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4918 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4919 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4920 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4921 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4922 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4923 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4924 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4925 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4926 fprintf (stderr, " [no-]cementing\n");
4927 if (major_collector.is_concurrent)
4928 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4929 if (major_collector.print_gc_param_usage)
4930 major_collector.print_gc_param_usage ();
4931 if (sgen_minor_collector.print_gc_param_usage)
4932 sgen_minor_collector.print_gc_param_usage ();
4933 fprintf (stderr, " Experimental options:\n");
4934 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4935 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);
4936 fprintf (stderr, "\n");
4938 usage_printed = TRUE;
4943 if (major_collector.is_concurrent)
4944 sgen_workers_init (1);
4946 if (major_collector_opt)
4947 g_free (major_collector_opt);
4949 if (minor_collector_opt)
4950 g_free (minor_collector_opt);
4954 sgen_cement_init (cement_enabled);
4956 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4957 gboolean usage_printed = FALSE;
4959 opts = g_strsplit (env, ",", -1);
4960 for (ptr = opts; ptr && *ptr; ptr ++) {
4962 if (!strcmp (opt, ""))
4964 if (opt [0] >= '0' && opt [0] <= '9') {
4965 gc_debug_level = atoi (opt);
4970 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4971 gc_debug_file = fopen (rf, "wb");
4973 gc_debug_file = stderr;
4976 } else if (!strcmp (opt, "print-allowance")) {
4977 debug_print_allowance = TRUE;
4978 } else if (!strcmp (opt, "print-pinning")) {
4979 do_pin_stats = TRUE;
4980 } else if (!strcmp (opt, "verify-before-allocs")) {
4981 verify_before_allocs = 1;
4982 has_per_allocation_action = TRUE;
4983 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4984 char *arg = strchr (opt, '=') + 1;
4985 verify_before_allocs = atoi (arg);
4986 has_per_allocation_action = TRUE;
4987 } else if (!strcmp (opt, "collect-before-allocs")) {
4988 collect_before_allocs = 1;
4989 has_per_allocation_action = TRUE;
4990 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4991 char *arg = strchr (opt, '=') + 1;
4992 has_per_allocation_action = TRUE;
4993 collect_before_allocs = atoi (arg);
4994 } else if (!strcmp (opt, "verify-before-collections")) {
4995 whole_heap_check_before_collection = TRUE;
4996 } else if (!strcmp (opt, "check-at-minor-collections")) {
4997 consistency_check_at_minor_collection = TRUE;
4998 nursery_clear_policy = CLEAR_AT_GC;
4999 } else if (!strcmp (opt, "mod-union-consistency-check")) {
5000 if (!major_collector.is_concurrent) {
5001 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
5004 mod_union_consistency_check = TRUE;
5005 } else if (!strcmp (opt, "check-mark-bits")) {
5006 check_mark_bits_after_major_collection = TRUE;
5007 } else if (!strcmp (opt, "check-nursery-pinned")) {
5008 check_nursery_objects_pinned = TRUE;
5009 } else if (!strcmp (opt, "xdomain-checks")) {
5010 xdomain_checks = TRUE;
5011 } else if (!strcmp (opt, "clear-at-gc")) {
5012 nursery_clear_policy = CLEAR_AT_GC;
5013 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
5014 nursery_clear_policy = CLEAR_AT_GC;
5015 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
5016 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
5017 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
5018 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
5019 } else if (!strcmp (opt, "check-scan-starts")) {
5020 do_scan_starts_check = TRUE;
5021 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
5022 do_verify_nursery = TRUE;
5023 } else if (!strcmp (opt, "check-concurrent")) {
5024 if (!major_collector.is_concurrent) {
5025 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
5028 do_concurrent_checks = TRUE;
5029 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
5030 do_dump_nursery_content = TRUE;
5031 } else if (!strcmp (opt, "no-managed-allocator")) {
5032 sgen_set_use_managed_allocator (FALSE);
5033 } else if (!strcmp (opt, "disable-minor")) {
5034 disable_minor_collections = TRUE;
5035 } else if (!strcmp (opt, "disable-major")) {
5036 disable_major_collections = TRUE;
5037 } else if (g_str_has_prefix (opt, "heap-dump=")) {
5038 char *filename = strchr (opt, '=') + 1;
5039 nursery_clear_policy = CLEAR_AT_GC;
5040 heap_dump_file = fopen (filename, "w");
5041 if (heap_dump_file) {
5042 fprintf (heap_dump_file, "<sgen-dump>\n");
5043 do_pin_stats = TRUE;
5045 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
5046 char *filename = strchr (opt, '=') + 1;
5047 char *colon = strrchr (filename, ':');
5050 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
5051 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
5056 binary_protocol_init (filename, (long long)limit);
5057 } else if (!strcmp (opt, "nursery-canaries")) {
5058 do_verify_nursery = TRUE;
5059 sgen_set_use_managed_allocator (FALSE);
5060 enable_nursery_canaries = TRUE;
5061 } else if (!strcmp (opt, "do-not-finalize")) {
5062 do_not_finalize = TRUE;
5063 } else if (!strcmp (opt, "log-finalizers")) {
5064 log_finalizers = TRUE;
5065 } else if (!sgen_bridge_handle_gc_debug (opt)) {
5066 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
5071 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);
5072 fprintf (stderr, "Valid <option>s are:\n");
5073 fprintf (stderr, " collect-before-allocs[=<n>]\n");
5074 fprintf (stderr, " verify-before-allocs[=<n>]\n");
5075 fprintf (stderr, " check-at-minor-collections\n");
5076 fprintf (stderr, " check-mark-bits\n");
5077 fprintf (stderr, " check-nursery-pinned\n");
5078 fprintf (stderr, " verify-before-collections\n");
5079 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5080 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5081 fprintf (stderr, " disable-minor\n");
5082 fprintf (stderr, " disable-major\n");
5083 fprintf (stderr, " xdomain-checks\n");
5084 fprintf (stderr, " check-concurrent\n");
5085 fprintf (stderr, " clear-[nursery-]at-gc\n");
5086 fprintf (stderr, " clear-at-tlab-creation\n");
5087 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5088 fprintf (stderr, " check-scan-starts\n");
5089 fprintf (stderr, " no-managed-allocator\n");
5090 fprintf (stderr, " print-allowance\n");
5091 fprintf (stderr, " print-pinning\n");
5092 fprintf (stderr, " heap-dump=<filename>\n");
5093 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5094 fprintf (stderr, " nursery-canaries\n");
5095 fprintf (stderr, " do-not-finalize\n");
5096 fprintf (stderr, " log-finalizers\n");
5097 sgen_bridge_print_gc_debug_usage ();
5098 fprintf (stderr, "\n");
5100 usage_printed = TRUE;
5106 if (check_mark_bits_after_major_collection)
5107 nursery_clear_policy = CLEAR_AT_GC;
5109 if (major_collector.post_param_init)
5110 major_collector.post_param_init (&major_collector);
5112 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5114 memset (&remset, 0, sizeof (remset));
5116 sgen_card_table_init (&remset);
5122 mono_gc_get_gc_name (void)
5127 static MonoMethod *write_barrier_method;
5130 sgen_is_critical_method (MonoMethod *method)
5132 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5136 sgen_has_critical_method (void)
5138 return write_barrier_method || sgen_has_managed_allocator ();
5144 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5146 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5147 #ifdef SGEN_ALIGN_NURSERY
5148 // if (ptr_in_nursery (ptr)) return;
5150 * Masking out the bits might be faster, but we would have to use 64 bit
5151 * immediates, which might be slower.
5153 mono_mb_emit_ldarg (mb, 0);
5154 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5155 mono_mb_emit_byte (mb, CEE_SHR_UN);
5156 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5157 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5159 if (!major_collector.is_concurrent) {
5160 // if (!ptr_in_nursery (*ptr)) return;
5161 mono_mb_emit_ldarg (mb, 0);
5162 mono_mb_emit_byte (mb, CEE_LDIND_I);
5163 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5164 mono_mb_emit_byte (mb, CEE_SHR_UN);
5165 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5166 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5169 int label_continue1, label_continue2;
5170 int dereferenced_var;
5172 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5173 mono_mb_emit_ldarg (mb, 0);
5174 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5175 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5177 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5178 mono_mb_emit_ldarg (mb, 0);
5179 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5180 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5183 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5186 mono_mb_patch_branch (mb, label_continue_1);
5187 mono_mb_patch_branch (mb, label_continue_2);
5189 // Dereference and store in local var
5190 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5191 mono_mb_emit_ldarg (mb, 0);
5192 mono_mb_emit_byte (mb, CEE_LDIND_I);
5193 mono_mb_emit_stloc (mb, dereferenced_var);
5195 if (!major_collector.is_concurrent) {
5196 // if (*ptr < sgen_get_nursery_start ()) return;
5197 mono_mb_emit_ldloc (mb, dereferenced_var);
5198 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5199 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5201 // if (*ptr >= sgen_get_nursery_end ()) return;
5202 mono_mb_emit_ldloc (mb, dereferenced_var);
5203 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5204 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5211 mono_gc_get_write_barrier (void)
5214 MonoMethodBuilder *mb;
5215 MonoMethodSignature *sig;
5216 #ifdef MANAGED_WBARRIER
5217 int i, nursery_check_labels [3];
5219 #ifdef HAVE_KW_THREAD
5220 int stack_end_offset = -1;
5222 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5223 g_assert (stack_end_offset != -1);
5227 // FIXME: Maybe create a separate version for ctors (the branch would be
5228 // correctly predicted more times)
5229 if (write_barrier_method)
5230 return write_barrier_method;
5232 /* Create the IL version of mono_gc_barrier_generic_store () */
5233 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5234 sig->ret = &mono_defaults.void_class->byval_arg;
5235 sig->params [0] = &mono_defaults.int_class->byval_arg;
5237 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5240 #ifdef MANAGED_WBARRIER
5241 emit_nursery_check (mb, nursery_check_labels);
5243 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5247 LDC_PTR sgen_cardtable
5249 address >> CARD_BITS
5253 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5254 LDC_PTR card_table_mask
5261 mono_mb_emit_ptr (mb, sgen_cardtable);
5262 mono_mb_emit_ldarg (mb, 0);
5263 mono_mb_emit_icon (mb, CARD_BITS);
5264 mono_mb_emit_byte (mb, CEE_SHR_UN);
5265 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5266 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5267 mono_mb_emit_byte (mb, CEE_AND);
5269 mono_mb_emit_byte (mb, CEE_ADD);
5270 mono_mb_emit_icon (mb, 1);
5271 mono_mb_emit_byte (mb, CEE_STIND_I1);
5274 for (i = 0; i < 3; ++i) {
5275 if (nursery_check_labels [i])
5276 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5278 mono_mb_emit_byte (mb, CEE_RET);
5280 mono_mb_emit_ldarg (mb, 0);
5281 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5282 mono_mb_emit_byte (mb, CEE_RET);
5285 res = mono_mb_create_method (mb, sig, 16);
5289 if (write_barrier_method) {
5290 /* Already created */
5291 mono_free_method (res);
5293 /* double-checked locking */
5294 mono_memory_barrier ();
5295 write_barrier_method = res;
5299 return write_barrier_method;
5303 mono_gc_get_description (void)
5305 return g_strdup ("sgen");
5309 mono_gc_set_desktop_mode (void)
5314 mono_gc_is_moving (void)
5320 mono_gc_is_disabled (void)
5326 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5333 sgen_get_nursery_clear_policy (void)
5335 return nursery_clear_policy;
5339 sgen_get_array_fill_vtable (void)
5341 if (!array_fill_vtable) {
5342 static MonoClass klass;
5343 static char _vtable[sizeof(MonoVTable)+8];
5344 MonoVTable* vtable = (MonoVTable*) ALIGN_TO(_vtable, 8);
5347 MonoDomain *domain = mono_get_root_domain ();
5350 klass.element_class = mono_defaults.byte_class;
5352 klass.instance_size = sizeof (MonoArray);
5353 klass.sizes.element_size = 1;
5354 klass.name = "array_filler_type";
5356 vtable->klass = &klass;
5358 vtable->gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5361 array_fill_vtable = vtable;
5363 return array_fill_vtable;
5373 sgen_gc_unlock (void)
5375 gboolean try_free = sgen_try_free_some_memory;
5376 sgen_try_free_some_memory = FALSE;
5377 mono_mutex_unlock (&gc_mutex);
5378 MONO_GC_UNLOCKED ();
5380 mono_thread_hazardous_try_free_some ();
5384 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5386 major_collector.iterate_live_block_ranges (callback);
5390 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5392 major_collector.scan_card_table (FALSE, queue);
5396 sgen_get_major_collector (void)
5398 return &major_collector;
5401 void mono_gc_set_skip_thread (gboolean skip)
5403 SgenThreadInfo *info = mono_thread_info_current ();
5406 info->gc_disabled = skip;
5411 sgen_get_remset (void)
5417 mono_gc_get_vtable_bits (MonoClass *class)
5420 /* FIXME move this to the bridge code */
5421 if (sgen_need_bridge_processing ()) {
5422 switch (sgen_bridge_class_kind (class)) {
5423 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5424 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5425 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5427 case GC_BRIDGE_OPAQUE_CLASS:
5428 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5430 case GC_BRIDGE_TRANSPARENT_CLASS:
5434 if (fin_callbacks.is_class_finalization_aware) {
5435 if (fin_callbacks.is_class_finalization_aware (class))
5436 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5442 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5449 sgen_check_whole_heap_stw (void)
5451 sgen_stop_world (0);
5452 sgen_clear_nursery_fragments ();
5453 sgen_check_whole_heap (FALSE);
5454 sgen_restart_world (0, NULL);
5458 sgen_gc_event_moves (void)
5460 if (moved_objects_idx) {
5461 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5462 moved_objects_idx = 0;
5467 sgen_timestamp (void)
5469 SGEN_TV_DECLARE (timestamp);
5470 SGEN_TV_GETTIME (timestamp);
5471 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5475 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5477 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5478 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5480 fin_callbacks = *callbacks;
5487 #endif /* HAVE_SGEN_GC */