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>
194 #include "metadata/sgen-gc.h"
195 #include "metadata/metadata-internals.h"
196 #include "metadata/class-internals.h"
197 #include "metadata/gc-internal.h"
198 #include "metadata/object-internals.h"
199 #include "metadata/threads.h"
200 #include "metadata/sgen-cardtable.h"
201 #include "metadata/sgen-protocol.h"
202 #include "metadata/sgen-archdep.h"
203 #include "metadata/sgen-bridge.h"
204 #include "metadata/sgen-memory-governor.h"
205 #include "metadata/sgen-hash-table.h"
206 #include "metadata/mono-gc.h"
207 #include "metadata/method-builder.h"
208 #include "metadata/profiler-private.h"
209 #include "metadata/monitor.h"
210 #include "metadata/mempool-internals.h"
211 #include "metadata/marshal.h"
212 #include "metadata/runtime.h"
213 #include "metadata/sgen-cardtable.h"
214 #include "metadata/sgen-pinning.h"
215 #include "metadata/sgen-workers.h"
216 #include "metadata/sgen-layout-stats.h"
217 #include "utils/mono-mmap.h"
218 #include "utils/mono-time.h"
219 #include "utils/mono-semaphore.h"
220 #include "utils/mono-counters.h"
221 #include "utils/mono-proclib.h"
222 #include "utils/mono-memory-model.h"
223 #include "utils/mono-logger-internal.h"
224 #include "utils/dtrace.h"
226 #include <mono/utils/mono-logger-internal.h>
227 #include <mono/utils/memcheck.h>
229 #if defined(__MACH__)
230 #include "utils/mach-support.h"
233 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
237 #include "mono/cil/opcode.def"
243 #undef pthread_create
245 #undef pthread_detach
248 * ######################################################################
249 * ######## Types and constants used by the GC.
250 * ######################################################################
253 /* 0 means not initialized, 1 is initialized, -1 means in progress */
254 static int gc_initialized = 0;
255 /* If set, check if we need to do something every X allocations */
256 gboolean has_per_allocation_action;
257 /* If set, do a heap check every X allocation */
258 guint32 verify_before_allocs = 0;
259 /* If set, do a minor collection before every X allocation */
260 guint32 collect_before_allocs = 0;
261 /* If set, do a whole heap check before each collection */
262 static gboolean whole_heap_check_before_collection = FALSE;
263 /* If set, do a heap consistency check before each minor collection */
264 static gboolean consistency_check_at_minor_collection = FALSE;
265 /* If set, do a mod union consistency check before each finishing collection pause */
266 static gboolean mod_union_consistency_check = FALSE;
267 /* If set, check whether mark bits are consistent after major collections */
268 static gboolean check_mark_bits_after_major_collection = FALSE;
269 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
270 static gboolean check_nursery_objects_pinned = FALSE;
271 /* If set, do a few checks when the concurrent collector is used */
272 static gboolean do_concurrent_checks = FALSE;
273 /* If set, check that there are no references to the domain left at domain unload */
274 static gboolean xdomain_checks = FALSE;
275 /* If not null, dump the heap after each collection into this file */
276 static FILE *heap_dump_file = NULL;
277 /* If set, mark stacks conservatively, even if precise marking is possible */
278 static gboolean conservative_stack_mark = FALSE;
279 /* If set, do a plausibility check on the scan_starts before and after
281 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 long long stat_objects_alloced_degraded = 0;
297 long long stat_bytes_alloced_degraded = 0;
299 long long stat_copy_object_called_nursery = 0;
300 long long stat_objects_copied_nursery = 0;
301 long long stat_copy_object_called_major = 0;
302 long long stat_objects_copied_major = 0;
304 long long stat_scan_object_called_nursery = 0;
305 long long stat_scan_object_called_major = 0;
307 long long stat_slots_allocated_in_vain;
309 long long stat_nursery_copy_object_failed_from_space = 0;
310 long long stat_nursery_copy_object_failed_forwarded = 0;
311 long long stat_nursery_copy_object_failed_pinned = 0;
312 long long 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 long long stat_pinned_objects = 0;
327 static long long time_minor_pre_collection_fragment_clear = 0;
328 static long long time_minor_pinning = 0;
329 static long long time_minor_scan_remsets = 0;
330 static long long time_minor_scan_pinned = 0;
331 static long long time_minor_scan_registered_roots = 0;
332 static long long time_minor_scan_thread_data = 0;
333 static long long time_minor_finish_gray_stack = 0;
334 static long long time_minor_fragment_creation = 0;
336 static long long time_major_pre_collection_fragment_clear = 0;
337 static long long time_major_pinning = 0;
338 static long long time_major_scan_pinned = 0;
339 static long long time_major_scan_registered_roots = 0;
340 static long long time_major_scan_thread_data = 0;
341 static long long time_major_scan_alloc_pinned = 0;
342 static long long time_major_scan_finalized = 0;
343 static long long time_major_scan_big_objects = 0;
344 static long long time_major_finish_gray_stack = 0;
345 static long long time_major_free_bigobjs = 0;
346 static long long time_major_los_sweep = 0;
347 static long long time_major_sweep = 0;
348 static long long time_major_fragment_creation = 0;
350 static SGEN_TV_DECLARE (time_major_conc_collection_start);
351 static SGEN_TV_DECLARE (time_major_conc_collection_end);
353 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
354 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
356 int gc_debug_level = 0;
359 static MonoGCFinalizerCallbacks fin_callbacks;
363 mono_gc_flush_info (void)
365 fflush (gc_debug_file);
369 #define TV_DECLARE SGEN_TV_DECLARE
370 #define TV_GETTIME SGEN_TV_GETTIME
371 #define TV_ELAPSED SGEN_TV_ELAPSED
372 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
374 SGEN_TV_DECLARE (sgen_init_timestamp);
376 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
378 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
380 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
381 #define object_is_pinned SGEN_OBJECT_IS_PINNED
382 #define pin_object SGEN_PIN_OBJECT
383 #define unpin_object SGEN_UNPIN_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 mword lowest_heap_address = ~(mword)0;
427 static mword highest_heap_address = 0;
429 LOCK_DECLARE (sgen_interruption_mutex);
430 static LOCK_DECLARE (pin_queue_mutex);
432 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
433 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
435 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
436 struct _FinalizeReadyEntry {
437 FinalizeReadyEntry *next;
441 typedef struct _EphemeronLinkNode EphemeronLinkNode;
443 struct _EphemeronLinkNode {
444 EphemeronLinkNode *next;
453 int current_collection_generation = -1;
454 volatile gboolean concurrent_collection_in_progress = FALSE;
456 /* objects that are ready to be finalized */
457 static FinalizeReadyEntry *fin_ready_list = NULL;
458 static FinalizeReadyEntry *critical_fin_list = NULL;
460 static EphemeronLinkNode *ephemeron_list;
462 /* registered roots: the key to the hash is the root start address */
464 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
466 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
467 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
468 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
469 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
471 static mword roots_size = 0; /* amount of memory in the root set */
473 #define GC_ROOT_NUM 32
475 int count; /* must be the first field */
476 void *objects [GC_ROOT_NUM];
477 int root_types [GC_ROOT_NUM];
478 uintptr_t extra_info [GC_ROOT_NUM];
482 notify_gc_roots (GCRootReport *report)
486 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
491 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
493 if (report->count == GC_ROOT_NUM)
494 notify_gc_roots (report);
495 report->objects [report->count] = object;
496 report->root_types [report->count] = rtype;
497 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
500 MonoNativeTlsKey thread_info_key;
502 #ifdef HAVE_KW_THREAD
503 __thread SgenThreadInfo *sgen_thread_info;
504 __thread char *stack_end;
507 /* The size of a TLAB */
508 /* The bigger the value, the less often we have to go to the slow path to allocate a new
509 * one, but the more space is wasted by threads not allocating much memory.
511 * FIXME: Make this self-tuning for each thread.
513 guint32 tlab_size = (1024 * 4);
515 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
517 /* Functions supplied by the runtime to be called by the GC */
518 static MonoGCCallbacks gc_callbacks;
520 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
521 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
523 #define ALIGN_UP SGEN_ALIGN_UP
525 #define MOVED_OBJECTS_NUM 64
526 static void *moved_objects [MOVED_OBJECTS_NUM];
527 static int moved_objects_idx = 0;
529 /* Vtable of the objects used to fill out nursery fragments before a collection */
530 static MonoVTable *array_fill_vtable;
532 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
533 MonoNativeThreadId main_gc_thread = NULL;
536 /*Object was pinned during the current collection*/
537 static mword objects_pinned;
540 * ######################################################################
541 * ######## Macros and function declarations.
542 * ######################################################################
546 align_pointer (void *ptr)
548 mword p = (mword)ptr;
549 p += sizeof (gpointer) - 1;
550 p &= ~ (sizeof (gpointer) - 1);
554 typedef SgenGrayQueue GrayQueue;
556 /* forward declarations */
557 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
558 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
559 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
560 static void report_finalizer_roots (void);
561 static void report_registered_roots (void);
563 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
564 static void finish_gray_stack (int generation, GrayQueue *queue);
566 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
569 static void init_stats (void);
571 static int mark_ephemerons_in_range (ScanCopyContext ctx);
572 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
573 static void null_ephemerons_for_domain (MonoDomain *domain);
575 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
577 SgenObjectOperations current_object_ops;
578 SgenMajorCollector major_collector;
579 SgenMinorCollector sgen_minor_collector;
580 static GrayQueue gray_queue;
582 static SgenRemeberedSet remset;
584 /* The gray queue to use from the main collection thread. */
585 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
588 * The gray queue a worker job must use. If we're not parallel or
589 * concurrent, we use the main gray queue.
591 static SgenGrayQueue*
592 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
594 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
598 gray_queue_redirect (SgenGrayQueue *queue)
600 gboolean wake = FALSE;
604 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
607 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
612 g_assert (concurrent_collection_in_progress);
613 if (sgen_workers_have_started ()) {
614 sgen_workers_wake_up_all ();
616 if (concurrent_collection_in_progress)
617 g_assert (current_collection_generation == -1);
623 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
625 while (start < end) {
629 if (!*(void**)start) {
630 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
635 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
641 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
642 CHECK_CANARY_FOR_OBJECT (obj);
643 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
644 callback (obj, size, data);
645 CANARIFY_SIZE (size);
647 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
655 need_remove_object_for_domain (char *start, MonoDomain *domain)
657 if (mono_object_domain (start) == domain) {
658 SGEN_LOG (4, "Need to cleanup object %p", start);
659 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
666 process_object_for_domain_clearing (char *start, MonoDomain *domain)
668 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
669 if (vt->klass == mono_defaults.internal_thread_class)
670 g_assert (mono_object_domain (start) == mono_get_root_domain ());
671 /* The object could be a proxy for an object in the domain
673 #ifndef DISABLE_REMOTING
674 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
675 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
677 /* The server could already have been zeroed out, so
678 we need to check for that, too. */
679 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
680 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
681 ((MonoRealProxy*)start)->unwrapped_server = NULL;
688 clear_domain_process_object (char *obj, MonoDomain *domain)
692 process_object_for_domain_clearing (obj, domain);
693 remove = need_remove_object_for_domain (obj, domain);
695 if (remove && ((MonoObject*)obj)->synchronisation) {
696 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
698 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
705 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
707 if (clear_domain_process_object (obj, domain)) {
708 CANARIFY_SIZE (size);
709 memset (obj, 0, size);
714 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
716 clear_domain_process_object (obj, domain);
720 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
722 if (need_remove_object_for_domain (obj, domain))
723 major_collector.free_non_pinned_object (obj, size);
727 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
729 if (need_remove_object_for_domain (obj, domain))
730 major_collector.free_pinned_object (obj, size);
734 * When appdomains are unloaded we can easily remove objects that have finalizers,
735 * but all the others could still be present in random places on the heap.
736 * We need a sweep to get rid of them even though it's going to be costly
738 * The reason we need to remove them is because we access the vtable and class
739 * structures to know the object size and the reference bitmap: once the domain is
740 * unloaded the point to random memory.
743 mono_gc_clear_domain (MonoDomain * domain)
745 LOSObject *bigobj, *prev;
750 binary_protocol_domain_unload_begin (domain);
754 if (concurrent_collection_in_progress)
755 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
756 g_assert (!concurrent_collection_in_progress);
758 sgen_process_fin_stage_entries ();
759 sgen_process_dislink_stage_entries ();
761 sgen_clear_nursery_fragments ();
763 if (xdomain_checks && domain != mono_get_root_domain ()) {
764 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
765 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
766 sgen_check_for_xdomain_refs ();
769 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
770 to memory returned to the OS.*/
771 null_ephemerons_for_domain (domain);
773 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
774 sgen_null_links_for_domain (domain, i);
776 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
777 sgen_remove_finalizers_for_domain (domain, i);
779 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
780 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
782 /* We need two passes over major and large objects because
783 freeing such objects might give their memory back to the OS
784 (in the case of large objects) or obliterate its vtable
785 (pinned objects with major-copying or pinned and non-pinned
786 objects with major-mark&sweep), but we might need to
787 dereference a pointer from an object to another object if
788 the first object is a proxy. */
789 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
790 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
791 clear_domain_process_object (bigobj->data, domain);
794 for (bigobj = los_object_list; bigobj;) {
795 if (need_remove_object_for_domain (bigobj->data, domain)) {
796 LOSObject *to_free = bigobj;
798 prev->next = bigobj->next;
800 los_object_list = bigobj->next;
801 bigobj = bigobj->next;
802 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
803 sgen_los_free_object (to_free);
807 bigobj = bigobj->next;
809 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
810 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
812 if (domain == mono_get_root_domain ()) {
813 if (G_UNLIKELY (do_pin_stats))
814 sgen_pin_stats_print_class_stats ();
815 sgen_object_layout_dump (stdout);
818 sgen_restart_world (0, NULL);
820 binary_protocol_domain_unload_end (domain);
826 * sgen_add_to_global_remset:
828 * The global remset contains locations which point into newspace after
829 * a minor collection. This can happen if the objects they point to are pinned.
831 * LOCKING: If called from a parallel collector, the global remset
832 * lock must be held. For serial collectors that is not necessary.
835 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
837 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
839 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
841 if (!major_collector.is_concurrent) {
842 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
844 if (current_collection_generation == -1)
845 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
848 if (!object_is_pinned (obj))
849 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");
850 else if (sgen_cement_lookup_or_register (obj))
853 remset.record_pointer (ptr);
855 if (G_UNLIKELY (do_pin_stats))
856 sgen_pin_stats_register_global_remset (obj);
858 SGEN_LOG (8, "Adding global remset for %p", ptr);
859 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
863 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
864 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
865 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
866 vt->klass->name_space, vt->klass->name);
872 * sgen_drain_gray_stack:
874 * Scan objects in the gray stack until the stack is empty. This should be called
875 * frequently after each object is copied, to achieve better locality and cache
878 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
882 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
884 ScanObjectFunc scan_func = ctx.scan_func;
885 GrayQueue *queue = ctx.queue;
889 for (i = 0; i != max_objs; ++i) {
892 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
895 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
896 scan_func (obj, desc, queue);
898 } while (max_objs < 0);
903 * Addresses in the pin queue are already sorted. This function finds
904 * the object header for each address and pins the object. The
905 * addresses must be inside the nursery section. The (start of the)
906 * address array is overwritten with the addresses of the actually
907 * pinned objects. Return the number of pinned objects.
910 pin_objects_from_nursery_pin_queue (ScanCopyContext ctx)
912 GCMemSection *section = nursery_section;
913 void **start = section->pin_queue_start;
914 void **end = start + section->pin_queue_num_entries;
915 void *start_nursery = section->data;
916 void *end_nursery = section->next_data;
921 void *pinning_front = start_nursery;
923 void **definitely_pinned = start;
924 ScanObjectFunc scan_func = ctx.scan_func;
925 SgenGrayQueue *queue = ctx.queue;
927 sgen_nursery_allocator_prepare_for_pinning ();
929 while (start < end) {
930 void *obj_to_pin = NULL;
931 size_t obj_to_pin_size = 0;
936 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
937 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
944 SGEN_LOG (5, "Considering pinning addr %p", addr);
945 /* We've already processed everything up to pinning_front. */
946 if (addr < pinning_front) {
952 * Find the closest scan start <= addr. We might search backward in the
953 * scan_starts array because entries might be NULL. In the worst case we
954 * start at start_nursery.
956 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
957 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
958 search_start = (void*)section->scan_starts [idx];
959 if (!search_start || search_start > addr) {
962 search_start = section->scan_starts [idx];
963 if (search_start && search_start <= addr)
966 if (!search_start || search_start > addr)
967 search_start = start_nursery;
971 * If the pinning front is closer than the scan start we found, start
972 * searching at the front.
974 if (search_start < pinning_front)
975 search_start = pinning_front;
978 * Now addr should be in an object a short distance from search_start.
980 * search_start must point to zeroed mem or point to an object.
986 if (!*(void**)search_start) {
987 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
988 /* The loop condition makes sure we don't overrun addr. */
992 obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
994 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
995 /* This is the object we're looking for. */
996 obj_to_pin = search_start;
997 obj_to_pin_size = obj_size;
1001 /* Skip to the next object */
1002 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
1003 CHECK_CANARY_FOR_OBJECT (search_start);
1004 CANARIFY_SIZE (obj_size);
1005 CANARIFY_SIZE (obj_to_pin_size);
1007 search_start = (void*)((char*)search_start + obj_size);
1008 } while (search_start <= addr);
1010 /* We've searched past the address we were looking for. */
1012 pinning_front = search_start;
1013 goto next_pin_queue_entry;
1017 * We've found an object to pin. It might still be a dummy array, but we
1018 * can advance the pinning front in any case.
1020 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1023 * If this is a dummy array marking the beginning of a nursery
1024 * fragment, we don't pin it.
1026 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1027 goto next_pin_queue_entry;
1030 * Finally - pin the object!
1032 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1034 scan_func (obj_to_pin, desc, queue);
1036 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1037 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1038 binary_protocol_pin (obj_to_pin,
1039 (gpointer)LOAD_VTABLE (obj_to_pin),
1040 safe_object_get_size (obj_to_pin));
1042 #ifdef ENABLE_DTRACE
1043 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1044 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1045 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1046 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1047 sgen_safe_object_get_size (obj_to_pin),
1048 vt->klass->name_space, vt->klass->name, gen);
1052 pin_object (obj_to_pin);
1053 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1054 if (G_UNLIKELY (do_pin_stats))
1055 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1056 definitely_pinned [count] = obj_to_pin;
1060 next_pin_queue_entry:
1064 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1065 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1066 GCRootReport report;
1068 for (idx = 0; idx < count; ++idx)
1069 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1070 notify_gc_roots (&report);
1072 stat_pinned_objects += count;
1077 pin_objects_in_nursery (ScanCopyContext ctx)
1081 if (!nursery_section->pin_queue_num_entries)
1084 reduced_to = pin_objects_from_nursery_pin_queue (ctx);
1085 nursery_section->pin_queue_num_entries = reduced_to;
1087 nursery_section->pin_queue_start = NULL;
1092 sgen_pin_object (void *object, GrayQueue *queue)
1094 g_assert (!concurrent_collection_in_progress);
1096 SGEN_PIN_OBJECT (object);
1097 sgen_pin_stage_ptr (object);
1099 if (G_UNLIKELY (do_pin_stats))
1100 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1102 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor (object));
1103 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1105 #ifdef ENABLE_DTRACE
1106 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1107 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1108 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1109 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1115 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1119 gboolean major_pinned = FALSE;
1121 if (sgen_ptr_in_nursery (obj)) {
1122 if (SGEN_CAS_PTR (obj, SGEN_POINTER_TAG_PINNED (vt), vt) == vt) {
1123 sgen_pin_object (obj, queue);
1127 major_collector.pin_major_object (obj, queue);
1128 major_pinned = TRUE;
1131 vtable_word = *(mword*)obj;
1132 /*someone else forwarded it, update the pointer and bail out*/
1133 if (SGEN_POINTER_IS_TAGGED_FORWARDED (vtable_word)) {
1134 *ptr = SGEN_POINTER_UNTAG_VTABLE (vtable_word);
1138 /*someone pinned it, nothing to do.*/
1139 if (SGEN_POINTER_IS_TAGGED_PINNED (vtable_word) || major_pinned)
1144 /* Sort the addresses in array in increasing order.
1145 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1148 sgen_sort_addresses (void **array, size_t size)
1153 for (i = 1; i < size; ++i) {
1156 size_t parent = (child - 1) / 2;
1158 if (array [parent] >= array [child])
1161 tmp = array [parent];
1162 array [parent] = array [child];
1163 array [child] = tmp;
1169 for (i = size - 1; i > 0; --i) {
1172 array [i] = array [0];
1178 while (root * 2 + 1 <= end) {
1179 size_t child = root * 2 + 1;
1181 if (child < end && array [child] < array [child + 1])
1183 if (array [root] >= array [child])
1187 array [root] = array [child];
1188 array [child] = tmp;
1196 * Scan the memory between start and end and queue values which could be pointers
1197 * to the area between start_nursery and end_nursery for later consideration.
1198 * Typically used for thread stacks.
1201 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1205 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1206 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1209 while (start < end) {
1210 if (*start >= start_nursery && *start < end_nursery) {
1212 * *start can point to the middle of an object
1213 * note: should we handle pointing at the end of an object?
1214 * pinning in C# code disallows pointing at the end of an object
1215 * but there is some small chance that an optimizing C compiler
1216 * may keep the only reference to an object by pointing
1217 * at the end of it. We ignore this small chance for now.
1218 * Pointers to the end of an object are indistinguishable
1219 * from pointers to the start of the next object in memory
1220 * so if we allow that we'd need to pin two objects...
1221 * We queue the pointer in an array, the
1222 * array will then be sorted and uniqued. This way
1223 * we can coalesce several pinning pointers and it should
1224 * be faster since we'd do a memory scan with increasing
1225 * addresses. Note: we can align the address to the allocation
1226 * alignment, so the unique process is more effective.
1228 mword addr = (mword)*start;
1229 addr &= ~(ALLOC_ALIGN - 1);
1230 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1231 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1232 sgen_pin_stage_ptr ((void*)addr);
1235 if (G_UNLIKELY (do_pin_stats)) {
1236 if (ptr_in_nursery ((void*)addr))
1237 sgen_pin_stats_register_address ((char*)addr, pin_type);
1243 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1247 * The first thing we do in a collection is to identify pinned objects.
1248 * This function considers all the areas of memory that need to be
1249 * conservatively scanned.
1252 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1256 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);
1257 /* objects pinned from the API are inside these roots */
1258 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1259 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1260 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1261 } SGEN_HASH_TABLE_FOREACH_END;
1262 /* now deal with the thread stacks
1263 * in the future we should be able to conservatively scan only:
1264 * *) the cpu registers
1265 * *) the unmanaged stack frames
1266 * *) the _last_ managed stack frame
1267 * *) pointers slots in managed frames
1269 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1273 unpin_objects_from_queue (SgenGrayQueue *queue)
1278 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1281 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1282 SGEN_UNPIN_OBJECT (addr);
1287 CopyOrMarkObjectFunc func;
1289 } UserCopyOrMarkData;
1292 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1294 UserCopyOrMarkData *data = gc_data;
1296 data->func (obj, data->queue);
1300 * The memory area from start_root to end_root contains pointers to objects.
1301 * Their position is precisely described by @desc (this means that the pointer
1302 * can be either NULL or the pointer to the start of an object).
1303 * This functions copies them to to_space updates them.
1305 * This function is not thread-safe!
1308 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1310 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1311 SgenGrayQueue *queue = ctx.queue;
1313 switch (desc & ROOT_DESC_TYPE_MASK) {
1314 case ROOT_DESC_BITMAP:
1315 desc >>= ROOT_DESC_TYPE_SHIFT;
1317 if ((desc & 1) && *start_root) {
1318 copy_func (start_root, queue);
1319 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1320 sgen_drain_gray_stack (-1, ctx);
1326 case ROOT_DESC_COMPLEX: {
1327 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1328 gsize bwords = (*bitmap_data) - 1;
1329 void **start_run = start_root;
1331 while (bwords-- > 0) {
1332 gsize bmap = *bitmap_data++;
1333 void **objptr = start_run;
1335 if ((bmap & 1) && *objptr) {
1336 copy_func (objptr, queue);
1337 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1338 sgen_drain_gray_stack (-1, ctx);
1343 start_run += GC_BITS_PER_WORD;
1347 case ROOT_DESC_USER: {
1348 UserCopyOrMarkData data = { copy_func, queue };
1349 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1350 marker (start_root, single_arg_user_copy_or_mark, &data);
1353 case ROOT_DESC_RUN_LEN:
1354 g_assert_not_reached ();
1356 g_assert_not_reached ();
1361 reset_heap_boundaries (void)
1363 lowest_heap_address = ~(mword)0;
1364 highest_heap_address = 0;
1368 sgen_update_heap_boundaries (mword low, mword high)
1373 old = lowest_heap_address;
1376 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1379 old = highest_heap_address;
1382 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1386 * Allocate and setup the data structures needed to be able to allocate objects
1387 * in the nursery. The nursery is stored in nursery_section.
1390 alloc_nursery (void)
1392 GCMemSection *section;
1397 if (nursery_section)
1399 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1400 /* later we will alloc a larger area for the nursery but only activate
1401 * what we need. The rest will be used as expansion if we have too many pinned
1402 * objects in the existing nursery.
1404 /* FIXME: handle OOM */
1405 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1407 alloc_size = sgen_nursery_size;
1409 /* If there isn't enough space even for the nursery we should simply abort. */
1410 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1412 #ifdef SGEN_ALIGN_NURSERY
1413 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1415 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1417 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1418 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 ());
1419 section->data = section->next_data = data;
1420 section->size = alloc_size;
1421 section->end_data = data + sgen_nursery_size;
1422 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1423 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1424 section->num_scan_start = scan_starts;
1426 nursery_section = section;
1428 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1432 mono_gc_get_nursery (int *shift_bits, size_t *size)
1434 *size = sgen_nursery_size;
1435 #ifdef SGEN_ALIGN_NURSERY
1436 *shift_bits = DEFAULT_NURSERY_BITS;
1440 return sgen_get_nursery_start ();
1444 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1446 SgenThreadInfo *info = mono_thread_info_current ();
1448 /* Could be called from sgen_thread_unregister () with a NULL info */
1451 info->stopped_domain = domain;
1456 mono_gc_precise_stack_mark_enabled (void)
1458 return !conservative_stack_mark;
1462 mono_gc_get_logfile (void)
1464 return gc_debug_file;
1468 report_finalizer_roots_list (FinalizeReadyEntry *list)
1470 GCRootReport report;
1471 FinalizeReadyEntry *fin;
1474 for (fin = list; fin; fin = fin->next) {
1477 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1479 notify_gc_roots (&report);
1483 report_finalizer_roots (void)
1485 report_finalizer_roots_list (fin_ready_list);
1486 report_finalizer_roots_list (critical_fin_list);
1489 static GCRootReport *root_report;
1492 single_arg_report_root (void **obj, void *gc_data)
1495 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1499 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1501 switch (desc & ROOT_DESC_TYPE_MASK) {
1502 case ROOT_DESC_BITMAP:
1503 desc >>= ROOT_DESC_TYPE_SHIFT;
1505 if ((desc & 1) && *start_root) {
1506 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1512 case ROOT_DESC_COMPLEX: {
1513 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1514 gsize bwords = (*bitmap_data) - 1;
1515 void **start_run = start_root;
1517 while (bwords-- > 0) {
1518 gsize bmap = *bitmap_data++;
1519 void **objptr = start_run;
1521 if ((bmap & 1) && *objptr) {
1522 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1527 start_run += GC_BITS_PER_WORD;
1531 case ROOT_DESC_USER: {
1532 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1533 root_report = report;
1534 marker (start_root, single_arg_report_root, NULL);
1537 case ROOT_DESC_RUN_LEN:
1538 g_assert_not_reached ();
1540 g_assert_not_reached ();
1545 report_registered_roots_by_type (int root_type)
1547 GCRootReport report;
1551 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1552 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1553 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1554 } SGEN_HASH_TABLE_FOREACH_END;
1555 notify_gc_roots (&report);
1559 report_registered_roots (void)
1561 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1562 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1566 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1568 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1569 SgenGrayQueue *queue = ctx.queue;
1570 FinalizeReadyEntry *fin;
1572 for (fin = list; fin; fin = fin->next) {
1575 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1576 copy_func (&fin->object, queue);
1581 generation_name (int generation)
1583 switch (generation) {
1584 case GENERATION_NURSERY: return "nursery";
1585 case GENERATION_OLD: return "old";
1586 default: g_assert_not_reached ();
1591 sgen_generation_name (int generation)
1593 return generation_name (generation);
1596 SgenObjectOperations *
1597 sgen_get_current_object_ops (void){
1598 return ¤t_object_ops;
1603 finish_gray_stack (int generation, GrayQueue *queue)
1607 int done_with_ephemerons, ephemeron_rounds = 0;
1608 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1609 ScanObjectFunc scan_func = current_object_ops.scan_object;
1610 ScanCopyContext ctx = { scan_func, copy_func, queue };
1611 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1612 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1615 * We copied all the reachable objects. Now it's the time to copy
1616 * the objects that were not referenced by the roots, but by the copied objects.
1617 * we built a stack of objects pointed to by gray_start: they are
1618 * additional roots and we may add more items as we go.
1619 * We loop until gray_start == gray_objects which means no more objects have
1620 * been added. Note this is iterative: no recursion is involved.
1621 * We need to walk the LO list as well in search of marked big objects
1622 * (use a flag since this is needed only on major collections). We need to loop
1623 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1624 * To achieve better cache locality and cache usage, we drain the gray stack
1625 * frequently, after each object is copied, and just finish the work here.
1627 sgen_drain_gray_stack (-1, ctx);
1629 SGEN_LOG (2, "%s generation done", generation_name (generation));
1632 Reset bridge data, we might have lingering data from a previous collection if this is a major
1633 collection trigged by minor overflow.
1635 We must reset the gathered bridges since their original block might be evacuated due to major
1636 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1638 if (sgen_need_bridge_processing ())
1639 sgen_bridge_reset_data ();
1642 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1643 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1644 * objects that are in fact reachable.
1646 done_with_ephemerons = 0;
1648 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1649 sgen_drain_gray_stack (-1, ctx);
1651 } while (!done_with_ephemerons);
1653 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1655 if (sgen_need_bridge_processing ()) {
1656 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1657 sgen_drain_gray_stack (-1, ctx);
1658 sgen_collect_bridge_objects (generation, ctx);
1659 if (generation == GENERATION_OLD)
1660 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1663 Do the first bridge step here, as the collector liveness state will become useless after that.
1665 An important optimization is to only proccess the possibly dead part of the object graph and skip
1666 over all live objects as we transitively know everything they point must be alive too.
1668 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1670 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1671 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1674 sgen_bridge_processing_stw_step ();
1678 Make sure we drain the gray stack before processing disappearing links and finalizers.
1679 If we don't make sure it is empty we might wrongly see a live object as dead.
1681 sgen_drain_gray_stack (-1, ctx);
1684 We must clear weak links that don't track resurrection before processing object ready for
1685 finalization so they can be cleared before that.
1687 sgen_null_link_in_range (generation, TRUE, ctx);
1688 if (generation == GENERATION_OLD)
1689 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1692 /* walk the finalization queue and move also the objects that need to be
1693 * finalized: use the finalized objects as new roots so the objects they depend
1694 * on are also not reclaimed. As with the roots above, only objects in the nursery
1695 * are marked/copied.
1697 sgen_finalize_in_range (generation, ctx);
1698 if (generation == GENERATION_OLD)
1699 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1700 /* drain the new stack that might have been created */
1701 SGEN_LOG (6, "Precise scan of gray area post fin");
1702 sgen_drain_gray_stack (-1, ctx);
1705 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1707 done_with_ephemerons = 0;
1709 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1710 sgen_drain_gray_stack (-1, ctx);
1712 } while (!done_with_ephemerons);
1715 * Clear ephemeron pairs with unreachable keys.
1716 * We pass the copy func so we can figure out if an array was promoted or not.
1718 clear_unreachable_ephemerons (ctx);
1721 * We clear togglerefs only after all possible chances of revival are done.
1722 * This is semantically more inline with what users expect and it allows for
1723 * user finalizers to correctly interact with TR objects.
1725 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1728 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1731 * handle disappearing links
1732 * Note we do this after checking the finalization queue because if an object
1733 * survives (at least long enough to be finalized) we don't clear the link.
1734 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1735 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1738 g_assert (sgen_gray_object_queue_is_empty (queue));
1740 sgen_null_link_in_range (generation, FALSE, ctx);
1741 if (generation == GENERATION_OLD)
1742 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1743 if (sgen_gray_object_queue_is_empty (queue))
1745 sgen_drain_gray_stack (-1, ctx);
1748 g_assert (sgen_gray_object_queue_is_empty (queue));
1750 sgen_gray_object_queue_trim_free_list (queue);
1754 sgen_check_section_scan_starts (GCMemSection *section)
1757 for (i = 0; i < section->num_scan_start; ++i) {
1758 if (section->scan_starts [i]) {
1759 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1760 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1766 check_scan_starts (void)
1768 if (!do_scan_starts_check)
1770 sgen_check_section_scan_starts (nursery_section);
1771 major_collector.check_scan_starts ();
1775 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1779 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1780 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1781 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1782 } SGEN_HASH_TABLE_FOREACH_END;
1786 sgen_dump_occupied (char *start, char *end, char *section_start)
1788 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1792 sgen_dump_section (GCMemSection *section, const char *type)
1794 char *start = section->data;
1795 char *end = section->data + section->size;
1796 char *occ_start = NULL;
1798 char *old_start = NULL; /* just for debugging */
1800 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1802 while (start < end) {
1806 if (!*(void**)start) {
1808 sgen_dump_occupied (occ_start, start, section->data);
1811 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1814 g_assert (start < section->next_data);
1819 vt = (GCVTable*)LOAD_VTABLE (start);
1822 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1825 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1826 start - section->data,
1827 vt->klass->name_space, vt->klass->name,
1835 sgen_dump_occupied (occ_start, start, section->data);
1837 fprintf (heap_dump_file, "</section>\n");
1841 dump_object (MonoObject *obj, gboolean dump_location)
1843 static char class_name [1024];
1845 MonoClass *class = mono_object_class (obj);
1849 * Python's XML parser is too stupid to parse angle brackets
1850 * in strings, so we just ignore them;
1853 while (class->name [i] && j < sizeof (class_name) - 1) {
1854 if (!strchr ("<>\"", class->name [i]))
1855 class_name [j++] = class->name [i];
1858 g_assert (j < sizeof (class_name));
1861 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1862 class->name_space, class_name,
1863 safe_object_get_size (obj));
1864 if (dump_location) {
1865 const char *location;
1866 if (ptr_in_nursery (obj))
1867 location = "nursery";
1868 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1872 fprintf (heap_dump_file, " location=\"%s\"", location);
1874 fprintf (heap_dump_file, "/>\n");
1878 dump_heap (const char *type, int num, const char *reason)
1883 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1885 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1886 fprintf (heap_dump_file, ">\n");
1887 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1888 sgen_dump_internal_mem_usage (heap_dump_file);
1889 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1890 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1891 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1893 fprintf (heap_dump_file, "<pinned-objects>\n");
1894 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1895 dump_object (list->obj, TRUE);
1896 fprintf (heap_dump_file, "</pinned-objects>\n");
1898 sgen_dump_section (nursery_section, "nursery");
1900 major_collector.dump_heap (heap_dump_file);
1902 fprintf (heap_dump_file, "<los>\n");
1903 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1904 dump_object ((MonoObject*)bigobj->data, FALSE);
1905 fprintf (heap_dump_file, "</los>\n");
1907 fprintf (heap_dump_file, "</collection>\n");
1911 sgen_register_moved_object (void *obj, void *destination)
1913 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1915 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1916 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1917 moved_objects_idx = 0;
1919 moved_objects [moved_objects_idx++] = obj;
1920 moved_objects [moved_objects_idx++] = destination;
1926 static gboolean inited = FALSE;
1931 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1932 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pinning);
1933 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1934 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1935 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1936 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1937 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1938 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1940 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1941 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pinning);
1942 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1943 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1944 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1945 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1946 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1947 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1948 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1949 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1950 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1951 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_sweep);
1952 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1954 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
1956 #ifdef HEAVY_STATISTICS
1957 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1958 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1959 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1960 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1961 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1962 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1963 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1964 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1965 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1967 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
1968 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
1970 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
1971 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
1972 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
1973 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
1975 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
1976 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
1978 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
1980 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
1981 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
1982 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
1983 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
1985 sgen_nursery_allocator_init_heavy_stats ();
1986 sgen_alloc_init_heavy_stats ();
1994 reset_pinned_from_failed_allocation (void)
1996 bytes_pinned_from_failed_allocation = 0;
2000 sgen_set_pinned_from_failed_allocation (mword objsize)
2002 bytes_pinned_from_failed_allocation += objsize;
2006 sgen_collection_is_concurrent (void)
2008 switch (current_collection_generation) {
2009 case GENERATION_NURSERY:
2011 case GENERATION_OLD:
2012 return concurrent_collection_in_progress;
2014 g_error ("Invalid current generation %d", current_collection_generation);
2019 sgen_concurrent_collection_in_progress (void)
2021 return concurrent_collection_in_progress;
2028 } FinishRememberedSetScanJobData;
2031 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2033 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2035 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2036 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2041 CopyOrMarkObjectFunc copy_or_mark_func;
2042 ScanObjectFunc scan_func;
2046 } ScanFromRegisteredRootsJobData;
2049 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2051 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2052 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2053 sgen_workers_get_job_gray_queue (worker_data) };
2055 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2056 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2063 } ScanThreadDataJobData;
2066 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2068 ScanThreadDataJobData *job_data = job_data_untyped;
2070 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2071 sgen_workers_get_job_gray_queue (worker_data));
2072 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2076 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2078 FinalizeReadyEntry *list = job_data_untyped;
2079 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2081 scan_finalizer_entries (list, ctx);
2085 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2087 g_assert (concurrent_collection_in_progress);
2088 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2092 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2094 g_assert (concurrent_collection_in_progress);
2095 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2099 verify_scan_starts (char *start, char *end)
2103 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2104 char *addr = nursery_section->scan_starts [i];
2105 if (addr > start && addr < end)
2106 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2111 verify_nursery (void)
2113 char *start, *end, *cur, *hole_start;
2115 if (!do_verify_nursery)
2118 if (nursery_canaries_enabled ())
2119 SGEN_LOG (1, "Checking nursery canaries...");
2121 /*This cleans up unused fragments */
2122 sgen_nursery_allocator_prepare_for_pinning ();
2124 hole_start = start = cur = sgen_get_nursery_start ();
2125 end = sgen_get_nursery_end ();
2130 if (!*(void**)cur) {
2131 cur += sizeof (void*);
2135 if (object_is_forwarded (cur))
2136 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2137 else if (object_is_pinned (cur))
2138 SGEN_LOG (1, "PINNED OBJ %p", cur);
2140 ss = safe_object_get_size ((MonoObject*)cur);
2141 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2142 verify_scan_starts (cur, cur + size);
2143 if (do_dump_nursery_content) {
2144 if (cur > hole_start)
2145 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2146 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 ());
2148 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2149 CHECK_CANARY_FOR_OBJECT (cur);
2150 CANARIFY_SIZE (size);
2158 * Checks that no objects in the nursery are fowarded or pinned. This
2159 * is a precondition to restarting the mutator while doing a
2160 * concurrent collection. Note that we don't clear fragments because
2161 * we depend on that having happened earlier.
2164 check_nursery_is_clean (void)
2166 char *start, *end, *cur;
2168 start = cur = sgen_get_nursery_start ();
2169 end = sgen_get_nursery_end ();
2174 if (!*(void**)cur) {
2175 cur += sizeof (void*);
2179 g_assert (!object_is_forwarded (cur));
2180 g_assert (!object_is_pinned (cur));
2182 ss = safe_object_get_size ((MonoObject*)cur);
2183 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2184 verify_scan_starts (cur, cur + size);
2191 init_gray_queue (void)
2193 if (sgen_collection_is_concurrent ()) {
2194 sgen_workers_init_distribute_gray_queue ();
2195 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2196 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2198 sgen_gray_object_queue_init (&gray_queue, NULL);
2203 * Collect objects in the nursery. Returns whether to trigger a major
2207 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2209 gboolean needs_major;
2210 size_t max_garbage_amount;
2212 FinishRememberedSetScanJobData *frssjd;
2213 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2214 ScanThreadDataJobData *stdjd;
2215 mword fragment_total;
2216 ScanCopyContext ctx;
2220 if (disable_minor_collections)
2223 TV_GETTIME (last_minor_collection_start_tv);
2224 atv = last_minor_collection_start_tv;
2226 MONO_GC_BEGIN (GENERATION_NURSERY);
2227 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2231 #ifndef DISABLE_PERFCOUNTERS
2232 mono_perfcounters->gc_collections0++;
2235 current_collection_generation = GENERATION_NURSERY;
2236 current_object_ops = sgen_minor_collector.serial_ops;
2238 reset_pinned_from_failed_allocation ();
2240 check_scan_starts ();
2242 sgen_nursery_alloc_prepare_for_minor ();
2246 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2247 /* FIXME: optimize later to use the higher address where an object can be present */
2248 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2250 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 ()));
2251 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2252 g_assert (nursery_section->size >= max_garbage_amount);
2254 /* world must be stopped already */
2256 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2258 if (xdomain_checks) {
2259 sgen_clear_nursery_fragments ();
2260 sgen_check_for_xdomain_refs ();
2263 nursery_section->next_data = nursery_next;
2265 major_collector.start_nursery_collection ();
2267 sgen_memgov_minor_collection_start ();
2271 gc_stats.minor_gc_count ++;
2273 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2275 sgen_process_fin_stage_entries ();
2276 sgen_process_dislink_stage_entries ();
2278 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2280 /* pin from pinned handles */
2281 sgen_init_pinning ();
2282 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2283 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2284 /* pin cemented objects */
2285 sgen_pin_cemented_objects ();
2286 /* identify pinned objects */
2287 sgen_optimize_pin_queue ();
2288 sgen_pinning_setup_section (nursery_section);
2289 ctx.scan_func = NULL;
2290 ctx.copy_func = NULL;
2291 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2292 pin_objects_in_nursery (ctx);
2293 sgen_pinning_trim_queue_to_section (nursery_section);
2296 time_minor_pinning += TV_ELAPSED (btv, atv);
2297 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2298 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2300 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2302 if (whole_heap_check_before_collection) {
2303 sgen_clear_nursery_fragments ();
2304 sgen_check_whole_heap (finish_up_concurrent_mark);
2306 if (consistency_check_at_minor_collection)
2307 sgen_check_consistency ();
2309 sgen_workers_start_all_workers ();
2310 sgen_workers_start_marking ();
2312 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2313 frssjd->heap_start = sgen_get_nursery_start ();
2314 frssjd->heap_end = nursery_next;
2315 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2317 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2319 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2320 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2322 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2324 /* FIXME: why is this here? */
2325 ctx.scan_func = current_object_ops.scan_object;
2326 ctx.copy_func = NULL;
2327 ctx.queue = &gray_queue;
2328 sgen_drain_gray_stack (-1, ctx);
2330 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2331 report_registered_roots ();
2332 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2333 report_finalizer_roots ();
2335 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2337 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2339 /* registered roots, this includes static fields */
2340 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2341 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2342 scrrjd_normal->scan_func = current_object_ops.scan_object;
2343 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2344 scrrjd_normal->heap_end = nursery_next;
2345 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2346 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2348 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2349 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2350 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2351 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2352 scrrjd_wbarrier->heap_end = nursery_next;
2353 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2354 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2357 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2359 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2362 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2363 stdjd->heap_start = sgen_get_nursery_start ();
2364 stdjd->heap_end = nursery_next;
2365 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2368 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2371 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2373 g_assert (!sgen_collection_is_concurrent ());
2375 /* Scan the list of objects ready for finalization. If */
2376 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2377 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2379 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2381 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2383 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2384 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2386 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2389 * The (single-threaded) finalization code might have done
2390 * some copying/marking so we can only reset the GC thread's
2391 * worker data here instead of earlier when we joined the
2394 sgen_workers_reset_data ();
2396 if (objects_pinned) {
2397 sgen_optimize_pin_queue ();
2398 sgen_pinning_setup_section (nursery_section);
2401 /* walk the pin_queue, build up the fragment list of free memory, unmark
2402 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2405 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2406 fragment_total = sgen_build_nursery_fragments (nursery_section,
2407 nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2409 if (!fragment_total)
2412 /* Clear TLABs for all threads */
2413 sgen_clear_tlabs ();
2415 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2417 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2418 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2420 if (consistency_check_at_minor_collection)
2421 sgen_check_major_refs ();
2423 major_collector.finish_nursery_collection ();
2425 TV_GETTIME (last_minor_collection_end_tv);
2426 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2429 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2431 /* prepare the pin queue for the next collection */
2432 sgen_finish_pinning ();
2433 if (fin_ready_list || critical_fin_list) {
2434 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2435 mono_gc_finalize_notify ();
2437 sgen_pin_stats_reset ();
2438 /* clear cemented hash */
2439 sgen_cement_clear_below_threshold ();
2441 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2443 remset.finish_minor_collection ();
2445 check_scan_starts ();
2447 binary_protocol_flush_buffers (FALSE);
2449 sgen_memgov_minor_collection_end ();
2451 /*objects are late pinned because of lack of memory, so a major is a good call*/
2452 needs_major = objects_pinned > 0;
2453 current_collection_generation = -1;
2456 MONO_GC_END (GENERATION_NURSERY);
2457 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY);
2459 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2460 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2466 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2469 * This is called on all objects in the nursery, including pinned ones, so we need
2470 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2472 ctx->scan_func (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2476 scan_nursery_objects (ScanCopyContext ctx)
2478 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2479 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2483 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2488 /* FIXME: only use these values for the precise scan
2489 * note that to_space pointers should be excluded anyway...
2491 char *heap_start = NULL;
2492 char *heap_end = (char*)-1;
2493 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2494 GCRootReport root_report = { 0 };
2495 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2496 ScanThreadDataJobData *stdjd;
2497 ScanCopyContext ctx;
2499 if (concurrent_collection_in_progress) {
2500 /*This cleans up unused fragments */
2501 sgen_nursery_allocator_prepare_for_pinning ();
2503 if (do_concurrent_checks)
2504 check_nursery_is_clean ();
2506 /* The concurrent collector doesn't touch the nursery. */
2507 sgen_nursery_alloc_prepare_for_major ();
2514 /* Pinning depends on this */
2515 sgen_clear_nursery_fragments ();
2517 if (whole_heap_check_before_collection)
2518 sgen_check_whole_heap (finish_up_concurrent_mark);
2521 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2523 if (!sgen_collection_is_concurrent ())
2524 nursery_section->next_data = sgen_get_nursery_end ();
2525 /* we should also coalesce scanning from sections close to each other
2526 * and deal with pointers outside of the sections later.
2530 *major_collector.have_swept = FALSE;
2532 if (xdomain_checks) {
2533 sgen_clear_nursery_fragments ();
2534 sgen_check_for_xdomain_refs ();
2537 if (!concurrent_collection_in_progress) {
2538 /* Remsets are not useful for a major collection */
2539 remset.prepare_for_major_collection ();
2542 sgen_process_fin_stage_entries ();
2543 sgen_process_dislink_stage_entries ();
2546 sgen_init_pinning ();
2547 SGEN_LOG (6, "Collecting pinned addresses");
2548 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2550 if (!concurrent_collection_in_progress || finish_up_concurrent_mark) {
2551 if (major_collector.is_concurrent) {
2553 * The concurrent major collector cannot evict
2554 * yet, so we need to pin cemented objects to
2555 * not break some asserts.
2557 * FIXME: We could evict now!
2559 sgen_pin_cemented_objects ();
2562 if (!concurrent_collection_in_progress)
2563 sgen_cement_reset ();
2566 sgen_optimize_pin_queue ();
2569 * The concurrent collector doesn't move objects, neither on
2570 * the major heap nor in the nursery, so we can mark even
2571 * before pinning has finished. For the non-concurrent
2572 * collector we start the workers after pinning.
2574 if (concurrent_collection_in_progress) {
2575 sgen_workers_start_all_workers ();
2576 sgen_workers_start_marking ();
2580 * pin_queue now contains all candidate pointers, sorted and
2581 * uniqued. We must do two passes now to figure out which
2582 * objects are pinned.
2584 * The first is to find within the pin_queue the area for each
2585 * section. This requires that the pin_queue be sorted. We
2586 * also process the LOS objects and pinned chunks here.
2588 * The second, destructive, pass is to reduce the section
2589 * areas to pointers to the actually pinned objects.
2591 SGEN_LOG (6, "Pinning from sections");
2592 /* first pass for the sections */
2593 sgen_find_section_pin_queue_start_end (nursery_section);
2594 major_collector.find_pin_queue_start_ends (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2595 /* identify possible pointers to the insize of large objects */
2596 SGEN_LOG (6, "Pinning from large objects");
2597 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2599 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy)) {
2600 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2602 #ifdef ENABLE_DTRACE
2603 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2604 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2605 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2609 if (sgen_los_object_is_pinned (bigobj->data)) {
2610 g_assert (finish_up_concurrent_mark);
2613 sgen_los_pin_object (bigobj->data);
2614 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2615 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2616 if (G_UNLIKELY (do_pin_stats))
2617 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2618 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));
2621 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2625 notify_gc_roots (&root_report);
2626 /* second pass for the sections */
2627 ctx.scan_func = concurrent_collection_in_progress ? current_object_ops.scan_object : NULL;
2628 ctx.copy_func = NULL;
2629 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2632 * Concurrent mark never follows references into the nursery.
2633 * In the start and finish pauses we must scan live nursery
2634 * objects, though. We could simply scan all nursery objects,
2635 * but that would be conservative. The easiest way is to do a
2636 * nursery collection, which copies all live nursery objects
2637 * (except pinned ones, with the simple nursery) to the major
2638 * heap. Scanning the mod union table later will then scan
2639 * those promoted objects, provided they're reachable. Pinned
2640 * objects in the nursery - which we can trivially find in the
2641 * pinning queue - are treated as roots in the mark pauses.
2643 * The split nursery complicates the latter part because
2644 * non-pinned objects can survive in the nursery. That's why
2645 * we need to do a full front-to-back scan of the nursery,
2646 * marking all objects.
2648 * Non-concurrent mark evacuates from the nursery, so it's
2649 * sufficient to just scan pinned nursery objects.
2651 if (concurrent_collection_in_progress && sgen_minor_collector.is_split) {
2652 scan_nursery_objects (ctx);
2654 pin_objects_in_nursery (ctx);
2655 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2656 sgen_check_nursery_objects_pinned (!concurrent_collection_in_progress || finish_up_concurrent_mark);
2659 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2660 if (old_next_pin_slot)
2661 *old_next_pin_slot = sgen_get_pinned_count ();
2664 time_major_pinning += TV_ELAPSED (atv, btv);
2665 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2666 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2668 major_collector.init_to_space ();
2670 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2671 main_gc_thread = mono_native_thread_self ();
2674 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2675 report_registered_roots ();
2677 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2679 /* registered roots, this includes static fields */
2680 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2681 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2682 scrrjd_normal->scan_func = current_object_ops.scan_object;
2683 scrrjd_normal->heap_start = heap_start;
2684 scrrjd_normal->heap_end = heap_end;
2685 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2686 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2688 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2689 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2690 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2691 scrrjd_wbarrier->heap_start = heap_start;
2692 scrrjd_wbarrier->heap_end = heap_end;
2693 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2694 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2697 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2700 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2701 stdjd->heap_start = heap_start;
2702 stdjd->heap_end = heap_end;
2703 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2706 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2709 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2711 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2712 report_finalizer_roots ();
2714 /* scan the list of objects ready for finalization */
2715 sgen_workers_enqueue_job (job_scan_finalizer_entries, fin_ready_list);
2716 sgen_workers_enqueue_job (job_scan_finalizer_entries, critical_fin_list);
2718 if (scan_mod_union) {
2719 g_assert (finish_up_concurrent_mark);
2721 /* Mod union card table */
2722 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2723 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2727 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2728 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2731 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2733 if (concurrent_collection_in_progress) {
2734 /* prepare the pin queue for the next collection */
2735 sgen_finish_pinning ();
2737 sgen_pin_stats_reset ();
2739 if (do_concurrent_checks)
2740 check_nursery_is_clean ();
2745 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2747 MONO_GC_BEGIN (GENERATION_OLD);
2748 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2750 current_collection_generation = GENERATION_OLD;
2751 #ifndef DISABLE_PERFCOUNTERS
2752 mono_perfcounters->gc_collections1++;
2755 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2758 g_assert (major_collector.is_concurrent);
2759 concurrent_collection_in_progress = TRUE;
2761 sgen_cement_concurrent_start ();
2763 current_object_ops = major_collector.major_concurrent_ops;
2765 current_object_ops = major_collector.major_ops;
2768 reset_pinned_from_failed_allocation ();
2770 sgen_memgov_major_collection_start ();
2772 //count_ref_nonref_objs ();
2773 //consistency_check ();
2775 check_scan_starts ();
2778 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2779 gc_stats.major_gc_count ++;
2781 if (major_collector.start_major_collection)
2782 major_collector.start_major_collection ();
2784 major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
2788 wait_for_workers_to_finish (void)
2790 while (!sgen_workers_all_done ())
2797 if (concurrent_collection_in_progress) {
2798 gray_queue_redirect (&gray_queue);
2799 sgen_workers_join ();
2802 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2804 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2805 main_gc_thread = NULL;
2810 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union)
2812 LOSObject *bigobj, *prevbo;
2818 if (concurrent_collection_in_progress)
2821 if (concurrent_collection_in_progress) {
2822 current_object_ops = major_collector.major_concurrent_ops;
2824 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
2827 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2829 if (do_concurrent_checks)
2830 check_nursery_is_clean ();
2832 current_object_ops = major_collector.major_ops;
2836 * The workers have stopped so we need to finish gray queue
2837 * work that might result from finalization in the main GC
2838 * thread. Redirection must therefore be turned off.
2840 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2841 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2843 /* all the objects in the heap */
2844 finish_gray_stack (GENERATION_OLD, &gray_queue);
2846 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2849 * The (single-threaded) finalization code might have done
2850 * some copying/marking so we can only reset the GC thread's
2851 * worker data here instead of earlier when we joined the
2854 sgen_workers_reset_data ();
2856 if (objects_pinned) {
2857 g_assert (!concurrent_collection_in_progress);
2859 /*This is slow, but we just OOM'd*/
2860 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2861 sgen_optimize_pin_queue ();
2862 sgen_find_section_pin_queue_start_end (nursery_section);
2866 reset_heap_boundaries ();
2867 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2869 if (check_mark_bits_after_major_collection)
2870 sgen_check_major_heap_marked ();
2872 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2874 /* sweep the big objects list */
2876 for (bigobj = los_object_list; bigobj;) {
2877 g_assert (!object_is_pinned (bigobj->data));
2878 if (sgen_los_object_is_pinned (bigobj->data)) {
2879 sgen_los_unpin_object (bigobj->data);
2880 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2883 /* not referenced anywhere, so we can free it */
2885 prevbo->next = bigobj->next;
2887 los_object_list = bigobj->next;
2889 bigobj = bigobj->next;
2890 sgen_los_free_object (to_free);
2894 bigobj = bigobj->next;
2898 time_major_free_bigobjs += TV_ELAPSED (atv, btv);
2903 time_major_los_sweep += TV_ELAPSED (btv, atv);
2905 major_collector.sweep ();
2907 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2910 time_major_sweep += TV_ELAPSED (atv, btv);
2912 if (!concurrent_collection_in_progress) {
2913 /* walk the pin_queue, build up the fragment list of free memory, unmark
2914 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2917 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
2920 /* prepare the pin queue for the next collection */
2921 sgen_finish_pinning ();
2923 /* Clear TLABs for all threads */
2924 sgen_clear_tlabs ();
2926 sgen_pin_stats_reset ();
2929 if (concurrent_collection_in_progress)
2930 sgen_cement_concurrent_finish ();
2931 sgen_cement_clear_below_threshold ();
2934 time_major_fragment_creation += TV_ELAPSED (btv, atv);
2937 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2939 if (fin_ready_list || critical_fin_list) {
2940 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2941 mono_gc_finalize_notify ();
2944 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2946 sgen_memgov_major_collection_end ();
2947 current_collection_generation = -1;
2949 major_collector.finish_major_collection ();
2951 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2953 if (concurrent_collection_in_progress)
2954 concurrent_collection_in_progress = FALSE;
2956 check_scan_starts ();
2958 binary_protocol_flush_buffers (FALSE);
2960 //consistency_check ();
2962 MONO_GC_END (GENERATION_OLD);
2963 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD);
2967 major_do_collection (const char *reason)
2969 TV_DECLARE (time_start);
2970 TV_DECLARE (time_end);
2971 size_t old_next_pin_slot;
2973 if (disable_major_collections)
2976 if (major_collector.get_and_reset_num_major_objects_marked) {
2977 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2978 g_assert (!num_marked);
2981 /* world must be stopped already */
2982 TV_GETTIME (time_start);
2984 major_start_collection (FALSE, &old_next_pin_slot);
2985 major_finish_collection (reason, old_next_pin_slot, FALSE);
2987 TV_GETTIME (time_end);
2988 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2990 /* FIXME: also report this to the user, preferably in gc-end. */
2991 if (major_collector.get_and_reset_num_major_objects_marked)
2992 major_collector.get_and_reset_num_major_objects_marked ();
2994 return bytes_pinned_from_failed_allocation > 0;
2998 major_start_concurrent_collection (const char *reason)
3000 TV_DECLARE (time_start);
3001 TV_DECLARE (time_end);
3002 long long num_objects_marked;
3004 if (disable_major_collections)
3007 TV_GETTIME (time_start);
3008 SGEN_TV_GETTIME (time_major_conc_collection_start);
3010 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3011 g_assert (num_objects_marked == 0);
3013 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3014 binary_protocol_concurrent_start ();
3016 // FIXME: store reason and pass it when finishing
3017 major_start_collection (TRUE, NULL);
3019 gray_queue_redirect (&gray_queue);
3020 sgen_workers_wait_for_jobs ();
3022 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3023 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3025 TV_GETTIME (time_end);
3026 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
3028 current_collection_generation = -1;
3032 major_update_or_finish_concurrent_collection (gboolean force_finish)
3034 TV_DECLARE (total_start);
3035 TV_DECLARE (total_end);
3036 SgenGrayQueue unpin_queue;
3037 memset (&unpin_queue, 0, sizeof (unpin_queue));
3039 TV_GETTIME (total_start);
3041 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3042 binary_protocol_concurrent_update_finish ();
3044 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3046 if (!force_finish && !sgen_workers_all_done ()) {
3047 major_collector.update_cardtable_mod_union ();
3048 sgen_los_update_cardtable_mod_union ();
3050 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3052 TV_GETTIME (total_end);
3053 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
3059 * The major collector can add global remsets which are processed in the finishing
3060 * nursery collection, below. That implies that the workers must have finished
3061 * marking before the nursery collection is allowed to run, otherwise we might miss
3064 wait_for_workers_to_finish ();
3066 SGEN_TV_GETTIME (time_major_conc_collection_end);
3067 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
3069 major_collector.update_cardtable_mod_union ();
3070 sgen_los_update_cardtable_mod_union ();
3072 collect_nursery (&unpin_queue, TRUE);
3074 if (mod_union_consistency_check)
3075 sgen_check_mod_union_consistency ();
3077 current_collection_generation = GENERATION_OLD;
3078 major_finish_collection ("finishing", -1, TRUE);
3080 if (whole_heap_check_before_collection)
3081 sgen_check_whole_heap (FALSE);
3083 unpin_objects_from_queue (&unpin_queue);
3084 sgen_gray_object_queue_deinit (&unpin_queue);
3086 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3088 TV_GETTIME (total_end);
3089 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3091 current_collection_generation = -1;
3097 * Ensure an allocation request for @size will succeed by freeing enough memory.
3099 * LOCKING: The GC lock MUST be held.
3102 sgen_ensure_free_space (size_t size)
3104 int generation_to_collect = -1;
3105 const char *reason = NULL;
3108 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3109 if (sgen_need_major_collection (size)) {
3110 reason = "LOS overflow";
3111 generation_to_collect = GENERATION_OLD;
3114 if (degraded_mode) {
3115 if (sgen_need_major_collection (size)) {
3116 reason = "Degraded mode overflow";
3117 generation_to_collect = GENERATION_OLD;
3119 } else if (sgen_need_major_collection (size)) {
3120 reason = "Minor allowance";
3121 generation_to_collect = GENERATION_OLD;
3123 generation_to_collect = GENERATION_NURSERY;
3124 reason = "Nursery full";
3128 if (generation_to_collect == -1) {
3129 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3130 generation_to_collect = GENERATION_OLD;
3131 reason = "Finish concurrent collection";
3135 if (generation_to_collect == -1)
3137 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3141 * LOCKING: Assumes the GC lock is held.
3144 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3146 TV_DECLARE (gc_end);
3147 GGTimingInfo infos [2];
3148 int overflow_generation_to_collect = -1;
3149 int oldest_generation_collected = generation_to_collect;
3150 const char *overflow_reason = NULL;
3152 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3154 binary_protocol_collection_force (generation_to_collect);
3156 g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3158 memset (infos, 0, sizeof (infos));
3159 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3161 infos [0].generation = generation_to_collect;
3162 infos [0].reason = reason;
3163 infos [0].is_overflow = FALSE;
3164 TV_GETTIME (infos [0].total_time);
3165 infos [1].generation = -1;
3167 sgen_stop_world (generation_to_collect);
3169 if (concurrent_collection_in_progress) {
3170 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3171 oldest_generation_collected = GENERATION_OLD;
3174 if (generation_to_collect == GENERATION_OLD)
3177 if (generation_to_collect == GENERATION_OLD &&
3178 allow_synchronous_major &&
3179 major_collector.want_synchronous_collection &&
3180 *major_collector.want_synchronous_collection) {
3181 wait_to_finish = TRUE;
3185 //FIXME extract overflow reason
3186 if (generation_to_collect == GENERATION_NURSERY) {
3187 if (collect_nursery (NULL, FALSE)) {
3188 overflow_generation_to_collect = GENERATION_OLD;
3189 overflow_reason = "Minor overflow";
3192 if (major_collector.is_concurrent) {
3193 g_assert (!concurrent_collection_in_progress);
3194 if (!wait_to_finish)
3195 collect_nursery (NULL, FALSE);
3198 if (major_collector.is_concurrent && !wait_to_finish) {
3199 major_start_concurrent_collection (reason);
3200 // FIXME: set infos[0] properly
3203 if (major_do_collection (reason)) {
3204 overflow_generation_to_collect = GENERATION_NURSERY;
3205 overflow_reason = "Excessive pinning";
3210 TV_GETTIME (gc_end);
3211 infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3214 if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3215 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3216 infos [1].generation = overflow_generation_to_collect;
3217 infos [1].reason = overflow_reason;
3218 infos [1].is_overflow = TRUE;
3219 infos [1].total_time = gc_end;
3221 if (overflow_generation_to_collect == GENERATION_NURSERY)
3222 collect_nursery (NULL, FALSE);
3224 major_do_collection (overflow_reason);
3226 TV_GETTIME (gc_end);
3227 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3229 /* keep events symmetric */
3230 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3232 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3235 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3237 /* this also sets the proper pointers for the next allocation */
3238 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3239 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3240 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3241 sgen_dump_pin_queue ();
3246 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3248 sgen_restart_world (oldest_generation_collected, infos);
3250 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3254 * ######################################################################
3255 * ######## Memory allocation from the OS
3256 * ######################################################################
3257 * This section of code deals with getting memory from the OS and
3258 * allocating memory for GC-internal data structures.
3259 * Internal memory can be handled with a freelist for small objects.
3265 G_GNUC_UNUSED static void
3266 report_internal_mem_usage (void)
3268 printf ("Internal memory usage:\n");
3269 sgen_report_internal_mem_usage ();
3270 printf ("Pinned memory usage:\n");
3271 major_collector.report_pinned_memory_usage ();
3275 * ######################################################################
3276 * ######## Finalization support
3277 * ######################################################################
3280 static inline gboolean
3281 sgen_major_is_object_alive (void *object)
3285 /* Oldgen objects can be pinned and forwarded too */
3286 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3290 * FIXME: major_collector.is_object_live() also calculates the
3291 * size. Avoid the double calculation.
3293 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3294 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3295 return sgen_los_object_is_pinned (object);
3297 return major_collector.is_object_live (object);
3301 * If the object has been forwarded it means it's still referenced from a root.
3302 * If it is pinned it's still alive as well.
3303 * A LOS object is only alive if we have pinned it.
3304 * Return TRUE if @obj is ready to be finalized.
3306 static inline gboolean
3307 sgen_is_object_alive (void *object)
3309 if (ptr_in_nursery (object))
3310 return sgen_nursery_is_object_alive (object);
3312 return sgen_major_is_object_alive (object);
3316 * This function returns true if @object is either alive or it belongs to the old gen
3317 * and we're currently doing a minor collection.
3320 sgen_is_object_alive_for_current_gen (char *object)
3322 if (ptr_in_nursery (object))
3323 return sgen_nursery_is_object_alive (object);
3325 if (current_collection_generation == GENERATION_NURSERY)
3328 return sgen_major_is_object_alive (object);
3332 * This function returns true if @object is either alive and belongs to the
3333 * current collection - major collections are full heap, so old gen objects
3334 * are never alive during a minor collection.
3337 sgen_is_object_alive_and_on_current_collection (char *object)
3339 if (ptr_in_nursery (object))
3340 return sgen_nursery_is_object_alive (object);
3342 if (current_collection_generation == GENERATION_NURSERY)
3345 return sgen_major_is_object_alive (object);
3350 sgen_gc_is_object_ready_for_finalization (void *object)
3352 return !sgen_is_object_alive (object);
3356 has_critical_finalizer (MonoObject *obj)
3360 if (!mono_defaults.critical_finalizer_object)
3363 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3365 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3369 is_finalization_aware (MonoObject *obj)
3371 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3372 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3376 sgen_queue_finalization_entry (MonoObject *obj)
3378 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3379 gboolean critical = has_critical_finalizer (obj);
3380 entry->object = obj;
3382 entry->next = critical_fin_list;
3383 critical_fin_list = entry;
3385 entry->next = fin_ready_list;
3386 fin_ready_list = entry;
3389 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3390 fin_callbacks.object_queued_for_finalization (obj);
3392 #ifdef ENABLE_DTRACE
3393 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3394 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3395 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3396 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3397 vt->klass->name_space, vt->klass->name, gen, critical);
3403 sgen_object_is_live (void *obj)
3405 return sgen_is_object_alive_and_on_current_collection (obj);
3408 /* LOCKING: requires that the GC lock is held */
3410 null_ephemerons_for_domain (MonoDomain *domain)
3412 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3415 MonoObject *object = (MonoObject*)current->array;
3417 if (object && !object->vtable) {
3418 EphemeronLinkNode *tmp = current;
3421 prev->next = current->next;
3423 ephemeron_list = current->next;
3425 current = current->next;
3426 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3429 current = current->next;
3434 /* LOCKING: requires that the GC lock is held */
3436 clear_unreachable_ephemerons (ScanCopyContext ctx)
3438 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3439 GrayQueue *queue = ctx.queue;
3440 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3442 Ephemeron *cur, *array_end;
3446 char *object = current->array;
3448 if (!sgen_is_object_alive_for_current_gen (object)) {
3449 EphemeronLinkNode *tmp = current;
3451 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3454 prev->next = current->next;
3456 ephemeron_list = current->next;
3458 current = current->next;
3459 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3464 copy_func ((void**)&object, queue);
3465 current->array = object;
3467 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3469 array = (MonoArray*)object;
3470 cur = mono_array_addr (array, Ephemeron, 0);
3471 array_end = cur + mono_array_length_fast (array);
3472 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3474 for (; cur < array_end; ++cur) {
3475 char *key = (char*)cur->key;
3477 if (!key || key == tombstone)
3480 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3481 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3482 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3484 if (!sgen_is_object_alive_for_current_gen (key)) {
3485 cur->key = tombstone;
3491 current = current->next;
3496 LOCKING: requires that the GC lock is held
3498 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3501 mark_ephemerons_in_range (ScanCopyContext ctx)
3503 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3504 GrayQueue *queue = ctx.queue;
3505 int nothing_marked = 1;
3506 EphemeronLinkNode *current = ephemeron_list;
3508 Ephemeron *cur, *array_end;
3511 for (current = ephemeron_list; current; current = current->next) {
3512 char *object = current->array;
3513 SGEN_LOG (5, "Ephemeron array at %p", object);
3515 /*It has to be alive*/
3516 if (!sgen_is_object_alive_for_current_gen (object)) {
3517 SGEN_LOG (5, "\tnot reachable");
3521 copy_func ((void**)&object, queue);
3523 array = (MonoArray*)object;
3524 cur = mono_array_addr (array, Ephemeron, 0);
3525 array_end = cur + mono_array_length_fast (array);
3526 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3528 for (; cur < array_end; ++cur) {
3529 char *key = cur->key;
3531 if (!key || key == tombstone)
3534 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3535 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3536 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3538 if (sgen_is_object_alive_for_current_gen (key)) {
3539 char *value = cur->value;
3541 copy_func ((void**)&cur->key, queue);
3543 if (!sgen_is_object_alive_for_current_gen (value))
3545 copy_func ((void**)&cur->value, queue);
3551 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3552 return nothing_marked;
3556 mono_gc_invoke_finalizers (void)
3558 FinalizeReadyEntry *entry = NULL;
3559 gboolean entry_is_critical = FALSE;
3562 /* FIXME: batch to reduce lock contention */
3563 while (fin_ready_list || critical_fin_list) {
3567 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3569 /* We have finalized entry in the last
3570 interation, now we need to remove it from
3573 *list = entry->next;
3575 FinalizeReadyEntry *e = *list;
3576 while (e->next != entry)
3578 e->next = entry->next;
3580 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3584 /* Now look for the first non-null entry. */
3585 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3588 entry_is_critical = FALSE;
3590 entry_is_critical = TRUE;
3591 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3596 g_assert (entry->object);
3597 num_ready_finalizers--;
3598 obj = entry->object;
3599 entry->object = NULL;
3600 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3608 g_assert (entry->object == NULL);
3610 /* the object is on the stack so it is pinned */
3611 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3612 mono_gc_run_finalize (obj, NULL);
3619 mono_gc_pending_finalizers (void)
3621 return fin_ready_list || critical_fin_list;
3625 * ######################################################################
3626 * ######## registered roots support
3627 * ######################################################################
3631 * We do not coalesce roots.
3634 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3636 RootRecord new_root;
3639 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3640 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3641 /* we allow changing the size and the descriptor (for thread statics etc) */
3643 size_t old_size = root->end_root - start;
3644 root->end_root = start + size;
3645 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3646 ((root->root_desc == 0) && (descr == NULL)));
3647 root->root_desc = (mword)descr;
3649 roots_size -= old_size;
3655 new_root.end_root = start + size;
3656 new_root.root_desc = (mword)descr;
3658 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3661 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);
3668 mono_gc_register_root (char *start, size_t size, void *descr)
3670 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3674 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3676 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3680 mono_gc_deregister_root (char* addr)
3686 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3687 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3688 roots_size -= (root.end_root - addr);
3694 * ######################################################################
3695 * ######## Thread handling (stop/start code)
3696 * ######################################################################
3699 unsigned int sgen_global_stop_count = 0;
3702 sgen_get_current_collection_generation (void)
3704 return current_collection_generation;
3708 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3710 gc_callbacks = *callbacks;
3714 mono_gc_get_gc_callbacks ()
3716 return &gc_callbacks;
3719 /* Variables holding start/end nursery so it won't have to be passed at every call */
3720 static void *scan_area_arg_start, *scan_area_arg_end;
3723 mono_gc_conservatively_scan_area (void *start, void *end)
3725 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3729 mono_gc_scan_object (void *obj, void *gc_data)
3731 UserCopyOrMarkData *data = gc_data;
3732 current_object_ops.copy_or_mark_object (&obj, data->queue);
3737 * Mark from thread stacks and registers.
3740 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3742 SgenThreadInfo *info;
3744 scan_area_arg_start = start_nursery;
3745 scan_area_arg_end = end_nursery;
3747 FOREACH_THREAD (info) {
3749 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);
3752 if (info->gc_disabled) {
3753 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);
3756 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3757 SGEN_LOG (3, "Skipping non-running thread %p, range: %p-%p, size: %td (state %d)", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, mono_thread_info_run_state (info));
3760 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 ());
3761 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3762 UserCopyOrMarkData data = { NULL, queue };
3763 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &data);
3764 } else if (!precise) {
3765 if (!conservative_stack_mark) {
3766 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3767 conservative_stack_mark = TRUE;
3769 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3774 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3775 start_nursery, end_nursery, PIN_TYPE_STACK);
3777 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3778 start_nursery, end_nursery, PIN_TYPE_STACK);
3781 } END_FOREACH_THREAD
3785 ptr_on_stack (void *ptr)
3787 gpointer stack_start = &stack_start;
3788 SgenThreadInfo *info = mono_thread_info_current ();
3790 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3796 sgen_thread_register (SgenThreadInfo* info, void *addr)
3799 guint8 *staddr = NULL;
3801 #ifndef HAVE_KW_THREAD
3802 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3804 g_assert (!mono_native_tls_get_value (thread_info_key));
3805 mono_native_tls_set_value (thread_info_key, info);
3807 sgen_thread_info = info;
3810 #ifdef SGEN_POSIX_STW
3811 info->stop_count = -1;
3815 info->stack_start = NULL;
3816 info->stopped_ip = NULL;
3817 info->stopped_domain = NULL;
3819 memset (&info->ctx, 0, sizeof (MonoContext));
3821 memset (&info->regs, 0, sizeof (info->regs));
3824 sgen_init_tlab_info (info);
3826 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3828 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3829 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3832 info->stack_start_limit = staddr;
3834 info->stack_end = staddr + stsize;
3836 gsize stack_bottom = (gsize)addr;
3837 stack_bottom += 4095;
3838 stack_bottom &= ~4095;
3839 info->stack_end = (char*)stack_bottom;
3842 #ifdef HAVE_KW_THREAD
3843 stack_end = info->stack_end;
3846 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3848 if (gc_callbacks.thread_attach_func)
3849 info->runtime_data = gc_callbacks.thread_attach_func ();
3854 sgen_thread_detach (SgenThreadInfo *p)
3856 /* If a delegate is passed to native code and invoked on a thread we dont
3857 * know about, the jit will register it with mono_jit_thread_attach, but
3858 * we have no way of knowing when that thread goes away. SGen has a TSD
3859 * so we assume that if the domain is still registered, we can detach
3862 if (mono_domain_get ())
3863 mono_thread_detach_internal (mono_thread_internal_current ());
3867 sgen_thread_unregister (SgenThreadInfo *p)
3869 MonoNativeThreadId tid;
3871 tid = mono_thread_info_get_tid (p);
3872 binary_protocol_thread_unregister ((gpointer)tid);
3873 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3875 #ifndef HAVE_KW_THREAD
3876 mono_native_tls_set_value (thread_info_key, NULL);
3878 sgen_thread_info = NULL;
3881 if (p->info.runtime_thread)
3882 mono_threads_add_joinable_thread ((gpointer)tid);
3884 if (gc_callbacks.thread_detach_func) {
3885 gc_callbacks.thread_detach_func (p->runtime_data);
3886 p->runtime_data = NULL;
3892 sgen_thread_attach (SgenThreadInfo *info)
3895 /*this is odd, can we get attached before the gc is inited?*/
3899 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3900 info->runtime_data = gc_callbacks.thread_attach_func ();
3903 mono_gc_register_thread (void *baseptr)
3905 return mono_thread_info_attach (baseptr) != NULL;
3909 * mono_gc_set_stack_end:
3911 * Set the end of the current threads stack to STACK_END. The stack space between
3912 * STACK_END and the real end of the threads stack will not be scanned during collections.
3915 mono_gc_set_stack_end (void *stack_end)
3917 SgenThreadInfo *info;
3920 info = mono_thread_info_current ();
3922 g_assert (stack_end < info->stack_end);
3923 info->stack_end = stack_end;
3928 #if USE_PTHREAD_INTERCEPT
3932 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3934 return pthread_create (new_thread, attr, start_routine, arg);
3938 mono_gc_pthread_join (pthread_t thread, void **retval)
3940 return pthread_join (thread, retval);
3944 mono_gc_pthread_detach (pthread_t thread)
3946 return pthread_detach (thread);
3950 mono_gc_pthread_exit (void *retval)
3952 mono_thread_info_detach ();
3953 pthread_exit (retval);
3954 g_assert_not_reached ();
3957 #endif /* USE_PTHREAD_INTERCEPT */
3960 * ######################################################################
3961 * ######## Write barriers
3962 * ######################################################################
3966 * Note: the write barriers first do the needed GC work and then do the actual store:
3967 * this way the value is visible to the conservative GC scan after the write barrier
3968 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
3969 * the conservative scan, otherwise by the remembered set scan.
3972 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
3974 HEAVY_STAT (++stat_wbarrier_set_field);
3975 if (ptr_in_nursery (field_ptr)) {
3976 *(void**)field_ptr = value;
3979 SGEN_LOG (8, "Adding remset at %p", field_ptr);
3981 binary_protocol_wbarrier (field_ptr, value, value->vtable);
3983 remset.wbarrier_set_field (obj, field_ptr, value);
3987 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
3989 HEAVY_STAT (++stat_wbarrier_set_arrayref);
3990 if (ptr_in_nursery (slot_ptr)) {
3991 *(void**)slot_ptr = value;
3994 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
3996 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
3998 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
4002 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
4004 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
4005 /*This check can be done without taking a lock since dest_ptr array is pinned*/
4006 if (ptr_in_nursery (dest_ptr) || count <= 0) {
4007 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
4011 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4012 if (binary_protocol_is_heavy_enabled ()) {
4014 for (i = 0; i < count; ++i) {
4015 gpointer dest = (gpointer*)dest_ptr + i;
4016 gpointer obj = *((gpointer*)src_ptr + i);
4018 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4023 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4026 static char *found_obj;
4029 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4031 char *ptr = user_data;
4033 if (ptr >= obj && ptr < obj + size) {
4034 g_assert (!found_obj);
4039 /* for use in the debugger */
4040 char* find_object_for_ptr (char *ptr);
4042 find_object_for_ptr (char *ptr)
4044 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4046 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4047 find_object_for_ptr_callback, ptr, TRUE);
4053 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4058 * Very inefficient, but this is debugging code, supposed to
4059 * be called from gdb, so we don't care.
4062 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4067 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4071 HEAVY_STAT (++stat_wbarrier_generic_store);
4073 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4074 /* FIXME: ptr_in_heap must be called with the GC lock held */
4075 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4076 char *start = find_object_for_ptr (ptr);
4077 MonoObject *value = *(MonoObject**)ptr;
4081 MonoObject *obj = (MonoObject*)start;
4082 if (obj->vtable->domain != value->vtable->domain)
4083 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4089 obj = *(gpointer*)ptr;
4091 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4093 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4094 SGEN_LOG (8, "Skipping remset at %p", ptr);
4099 * We need to record old->old pointer locations for the
4100 * concurrent collector.
4102 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4103 SGEN_LOG (8, "Skipping remset at %p", ptr);
4107 SGEN_LOG (8, "Adding remset at %p", ptr);
4109 remset.wbarrier_generic_nostore (ptr);
4113 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4115 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4116 *(void**)ptr = value;
4117 if (ptr_in_nursery (value))
4118 mono_gc_wbarrier_generic_nostore (ptr);
4119 sgen_dummy_use (value);
4122 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4123 * as an atomic operation with release semantics.
4126 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4128 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4130 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4132 InterlockedWritePointer (ptr, value);
4134 if (ptr_in_nursery (value))
4135 mono_gc_wbarrier_generic_nostore (ptr);
4137 sgen_dummy_use (value);
4140 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4142 mword *dest = _dest;
4147 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4152 size -= SIZEOF_VOID_P;
4157 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4159 #define HANDLE_PTR(ptr,obj) do { \
4160 gpointer o = *(gpointer*)(ptr); \
4162 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4163 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4168 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4170 #define SCAN_OBJECT_NOVTABLE
4171 #include "sgen-scan-object.h"
4176 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4178 HEAVY_STAT (++stat_wbarrier_value_copy);
4179 g_assert (klass->valuetype);
4181 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4183 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4184 size_t element_size = mono_class_value_size (klass, NULL);
4185 size_t size = count * element_size;
4186 mono_gc_memmove_atomic (dest, src, size);
4190 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4191 if (binary_protocol_is_heavy_enabled ()) {
4192 size_t element_size = mono_class_value_size (klass, NULL);
4194 for (i = 0; i < count; ++i) {
4195 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4196 (char*)src + i * element_size - sizeof (MonoObject),
4197 (mword) klass->gc_descr);
4202 remset.wbarrier_value_copy (dest, src, count, klass);
4206 * mono_gc_wbarrier_object_copy:
4208 * Write barrier to call when obj is the result of a clone or copy of an object.
4211 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4215 HEAVY_STAT (++stat_wbarrier_object_copy);
4217 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4218 size = mono_object_class (obj)->instance_size;
4219 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4220 size - sizeof (MonoObject));
4224 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4225 if (binary_protocol_is_heavy_enabled ())
4226 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4229 remset.wbarrier_object_copy (obj, src);
4234 * ######################################################################
4235 * ######## Other mono public interface functions.
4236 * ######################################################################
4239 #define REFS_SIZE 128
4242 MonoGCReferences callback;
4246 MonoObject *refs [REFS_SIZE];
4247 uintptr_t offsets [REFS_SIZE];
4251 #define HANDLE_PTR(ptr,obj) do { \
4253 if (hwi->count == REFS_SIZE) { \
4254 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4258 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4259 hwi->refs [hwi->count++] = *(ptr); \
4264 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4266 mword desc = sgen_obj_get_descriptor (start);
4268 #include "sgen-scan-object.h"
4272 walk_references (char *start, size_t size, void *data)
4274 HeapWalkInfo *hwi = data;
4277 collect_references (hwi, start, size);
4278 if (hwi->count || !hwi->called)
4279 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4283 * mono_gc_walk_heap:
4284 * @flags: flags for future use
4285 * @callback: a function pointer called for each object in the heap
4286 * @data: a user data pointer that is passed to callback
4288 * This function can be used to iterate over all the live objects in the heap:
4289 * for each object, @callback is invoked, providing info about the object's
4290 * location in memory, its class, its size and the objects it references.
4291 * For each referenced object it's offset from the object address is
4292 * reported in the offsets array.
4293 * The object references may be buffered, so the callback may be invoked
4294 * multiple times for the same object: in all but the first call, the size
4295 * argument will be zero.
4296 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4297 * profiler event handler.
4299 * Returns: a non-zero value if the GC doesn't support heap walking
4302 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4307 hwi.callback = callback;
4310 sgen_clear_nursery_fragments ();
4311 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4313 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4314 sgen_los_iterate_objects (walk_references, &hwi);
4320 mono_gc_collect (int generation)
4325 sgen_perform_collection (0, generation, "user request", TRUE);
4330 mono_gc_max_generation (void)
4336 mono_gc_collection_count (int generation)
4338 if (generation == 0)
4339 return gc_stats.minor_gc_count;
4340 return gc_stats.major_gc_count;
4344 mono_gc_get_used_size (void)
4348 tot = los_memory_usage;
4349 tot += nursery_section->next_data - nursery_section->data;
4350 tot += major_collector.get_used_size ();
4351 /* FIXME: account for pinned objects */
4357 mono_gc_get_los_limit (void)
4359 return MAX_SMALL_OBJ_SIZE;
4363 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4365 mono_unichar2 *new_end = str->chars + new_length;
4367 /* zero the discarded string. This null-delimits the string and allows
4368 * the space to be reclaimed by SGen. */
4370 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4371 CHECK_CANARY_FOR_OBJECT (str);
4372 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4373 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4375 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4378 str->length = new_length;
4382 mono_gc_user_markers_supported (void)
4388 mono_object_is_alive (MonoObject* o)
4394 mono_gc_get_generation (MonoObject *obj)
4396 if (ptr_in_nursery (obj))
4402 mono_gc_enable_events (void)
4407 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4409 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4413 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4415 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4419 mono_gc_weak_link_get (void **link_addr)
4421 void * volatile *link_addr_volatile;
4425 link_addr_volatile = link_addr;
4426 ptr = (void*)*link_addr_volatile;
4428 * At this point we have a hidden pointer. If the GC runs
4429 * here, it will not recognize the hidden pointer as a
4430 * reference, and if the object behind it is not referenced
4431 * elsewhere, it will be freed. Once the world is restarted
4432 * we reveal the pointer, giving us a pointer to a freed
4433 * object. To make sure we don't return it, we load the
4434 * hidden pointer again. If it's still the same, we can be
4435 * sure the object reference is valid.
4438 obj = (MonoObject*) REVEAL_POINTER (ptr);
4442 mono_memory_barrier ();
4445 * During the second bridge processing step the world is
4446 * running again. That step processes all weak links once
4447 * more to null those that refer to dead objects. Before that
4448 * is completed, those links must not be followed, so we
4449 * conservatively wait for bridge processing when any weak
4450 * link is dereferenced.
4452 if (G_UNLIKELY (bridge_processing_in_progress))
4453 mono_gc_wait_for_bridge_processing ();
4455 if ((void*)*link_addr_volatile != ptr)
4462 mono_gc_ephemeron_array_add (MonoObject *obj)
4464 EphemeronLinkNode *node;
4468 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4473 node->array = (char*)obj;
4474 node->next = ephemeron_list;
4475 ephemeron_list = node;
4477 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4484 mono_gc_set_allow_synchronous_major (gboolean flag)
4486 if (!major_collector.is_concurrent)
4489 allow_synchronous_major = flag;
4494 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4498 result = func (data);
4499 UNLOCK_INTERRUPTION;
4504 mono_gc_is_gc_thread (void)
4508 result = mono_thread_info_current () != NULL;
4514 is_critical_method (MonoMethod *method)
4516 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4520 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4524 va_start (ap, description_format);
4526 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4527 vfprintf (stderr, description_format, ap);
4529 fprintf (stderr, " - %s", fallback);
4530 fprintf (stderr, "\n");
4536 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4539 double val = strtod (opt, &endptr);
4540 if (endptr == opt) {
4541 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4544 else if (val < min || val > max) {
4545 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4553 mono_gc_base_init (void)
4555 MonoThreadInfoCallbacks cb;
4558 char *major_collector_opt = NULL;
4559 char *minor_collector_opt = NULL;
4560 size_t max_heap = 0;
4561 size_t soft_limit = 0;
4564 gboolean debug_print_allowance = FALSE;
4565 double allowance_ratio = 0, save_target = 0;
4566 gboolean have_split_nursery = FALSE;
4567 gboolean cement_enabled = TRUE;
4570 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4573 /* already inited */
4576 /* being inited by another thread */
4580 /* we will init it */
4583 g_assert_not_reached ();
4585 } while (result != 0);
4587 SGEN_TV_GETTIME (sgen_init_timestamp);
4589 LOCK_INIT (gc_mutex);
4591 pagesize = mono_pagesize ();
4592 gc_debug_file = stderr;
4594 cb.thread_register = sgen_thread_register;
4595 cb.thread_detach = sgen_thread_detach;
4596 cb.thread_unregister = sgen_thread_unregister;
4597 cb.thread_attach = sgen_thread_attach;
4598 cb.mono_method_is_critical = (gpointer)is_critical_method;
4600 cb.thread_exit = mono_gc_pthread_exit;
4601 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4604 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4606 LOCK_INIT (sgen_interruption_mutex);
4607 LOCK_INIT (pin_queue_mutex);
4609 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4610 opts = g_strsplit (env, ",", -1);
4611 for (ptr = opts; *ptr; ++ptr) {
4613 if (g_str_has_prefix (opt, "major=")) {
4614 opt = strchr (opt, '=') + 1;
4615 major_collector_opt = g_strdup (opt);
4616 } else if (g_str_has_prefix (opt, "minor=")) {
4617 opt = strchr (opt, '=') + 1;
4618 minor_collector_opt = g_strdup (opt);
4626 sgen_init_internal_allocator ();
4627 sgen_init_nursery_allocator ();
4628 sgen_init_fin_weak_hash ();
4630 sgen_init_hash_table ();
4631 sgen_init_descriptors ();
4632 sgen_init_gray_queues ();
4634 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4635 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4636 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4637 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4639 #ifndef HAVE_KW_THREAD
4640 mono_native_tls_alloc (&thread_info_key, NULL);
4641 #if defined(__APPLE__) || defined (HOST_WIN32)
4643 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4644 * where the two are the same.
4646 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4650 int tls_offset = -1;
4651 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4652 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4657 * This needs to happen before any internal allocations because
4658 * it inits the small id which is required for hazard pointer
4663 mono_thread_info_attach (&dummy);
4665 if (!minor_collector_opt) {
4666 sgen_simple_nursery_init (&sgen_minor_collector);
4668 if (!strcmp (minor_collector_opt, "simple")) {
4670 sgen_simple_nursery_init (&sgen_minor_collector);
4671 } else if (!strcmp (minor_collector_opt, "split")) {
4672 sgen_split_nursery_init (&sgen_minor_collector);
4673 have_split_nursery = TRUE;
4675 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4676 goto use_simple_nursery;
4680 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4681 use_marksweep_major:
4682 sgen_marksweep_init (&major_collector);
4683 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4684 sgen_marksweep_conc_init (&major_collector);
4686 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4687 goto use_marksweep_major;
4690 ///* Keep this the default for now */
4691 /* Precise marking is broken on all supported targets. Disable until fixed. */
4692 conservative_stack_mark = TRUE;
4694 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4697 gboolean usage_printed = FALSE;
4699 for (ptr = opts; *ptr; ++ptr) {
4701 if (!strcmp (opt, ""))
4703 if (g_str_has_prefix (opt, "major="))
4705 if (g_str_has_prefix (opt, "minor="))
4707 if (g_str_has_prefix (opt, "max-heap-size=")) {
4708 size_t max_heap_candidate = 0;
4709 opt = strchr (opt, '=') + 1;
4710 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4711 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4712 if (max_heap != max_heap_candidate)
4713 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4715 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4719 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4720 opt = strchr (opt, '=') + 1;
4721 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4722 if (soft_limit <= 0) {
4723 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4727 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4731 if (g_str_has_prefix (opt, "stack-mark=")) {
4732 opt = strchr (opt, '=') + 1;
4733 if (!strcmp (opt, "precise")) {
4734 conservative_stack_mark = FALSE;
4735 } else if (!strcmp (opt, "conservative")) {
4736 conservative_stack_mark = TRUE;
4738 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4739 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4743 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4744 opt = strchr (opt, '=') + 1;
4745 sgen_set_bridge_implementation (opt);
4748 if (g_str_has_prefix (opt, "toggleref-test")) {
4749 sgen_register_test_toggleref_callback ();
4754 if (g_str_has_prefix (opt, "nursery-size=")) {
4756 opt = strchr (opt, '=') + 1;
4757 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4758 #ifdef SGEN_ALIGN_NURSERY
4759 if ((val & (val - 1))) {
4760 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4764 if (val < SGEN_MAX_NURSERY_WASTE) {
4765 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4766 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4770 sgen_nursery_size = val;
4771 sgen_nursery_bits = 0;
4772 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4775 sgen_nursery_size = val;
4778 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4784 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4786 opt = strchr (opt, '=') + 1;
4787 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4788 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4793 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4795 opt = strchr (opt, '=') + 1;
4796 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4797 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4798 allowance_ratio = val;
4802 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4803 if (!major_collector.is_concurrent) {
4804 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4808 opt = strchr (opt, '=') + 1;
4810 if (!strcmp (opt, "yes")) {
4811 allow_synchronous_major = TRUE;
4812 } else if (!strcmp (opt, "no")) {
4813 allow_synchronous_major = FALSE;
4815 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4820 if (!strcmp (opt, "cementing")) {
4821 cement_enabled = TRUE;
4824 if (!strcmp (opt, "no-cementing")) {
4825 cement_enabled = FALSE;
4829 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4832 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4835 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4840 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4841 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4842 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4843 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4844 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4845 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4846 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4847 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4848 fprintf (stderr, " [no-]cementing\n");
4849 if (major_collector.is_concurrent)
4850 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4851 if (major_collector.print_gc_param_usage)
4852 major_collector.print_gc_param_usage ();
4853 if (sgen_minor_collector.print_gc_param_usage)
4854 sgen_minor_collector.print_gc_param_usage ();
4855 fprintf (stderr, " Experimental options:\n");
4856 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4857 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);
4858 fprintf (stderr, "\n");
4860 usage_printed = TRUE;
4865 if (major_collector.is_concurrent)
4866 sgen_workers_init (1);
4868 if (major_collector_opt)
4869 g_free (major_collector_opt);
4871 if (minor_collector_opt)
4872 g_free (minor_collector_opt);
4876 sgen_cement_init (cement_enabled);
4878 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4879 gboolean usage_printed = FALSE;
4881 opts = g_strsplit (env, ",", -1);
4882 for (ptr = opts; ptr && *ptr; ptr ++) {
4884 if (!strcmp (opt, ""))
4886 if (opt [0] >= '0' && opt [0] <= '9') {
4887 gc_debug_level = atoi (opt);
4893 char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
4895 char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
4897 gc_debug_file = fopen (rf, "wb");
4899 gc_debug_file = stderr;
4902 } else if (!strcmp (opt, "print-allowance")) {
4903 debug_print_allowance = TRUE;
4904 } else if (!strcmp (opt, "print-pinning")) {
4905 do_pin_stats = TRUE;
4906 } else if (!strcmp (opt, "verify-before-allocs")) {
4907 verify_before_allocs = 1;
4908 has_per_allocation_action = TRUE;
4909 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4910 char *arg = strchr (opt, '=') + 1;
4911 verify_before_allocs = atoi (arg);
4912 has_per_allocation_action = TRUE;
4913 } else if (!strcmp (opt, "collect-before-allocs")) {
4914 collect_before_allocs = 1;
4915 has_per_allocation_action = TRUE;
4916 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4917 char *arg = strchr (opt, '=') + 1;
4918 has_per_allocation_action = TRUE;
4919 collect_before_allocs = atoi (arg);
4920 } else if (!strcmp (opt, "verify-before-collections")) {
4921 whole_heap_check_before_collection = TRUE;
4922 } else if (!strcmp (opt, "check-at-minor-collections")) {
4923 consistency_check_at_minor_collection = TRUE;
4924 nursery_clear_policy = CLEAR_AT_GC;
4925 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4926 if (!major_collector.is_concurrent) {
4927 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4930 mod_union_consistency_check = TRUE;
4931 } else if (!strcmp (opt, "check-mark-bits")) {
4932 check_mark_bits_after_major_collection = TRUE;
4933 } else if (!strcmp (opt, "check-nursery-pinned")) {
4934 check_nursery_objects_pinned = TRUE;
4935 } else if (!strcmp (opt, "xdomain-checks")) {
4936 xdomain_checks = TRUE;
4937 } else if (!strcmp (opt, "clear-at-gc")) {
4938 nursery_clear_policy = CLEAR_AT_GC;
4939 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4940 nursery_clear_policy = CLEAR_AT_GC;
4941 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4942 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4943 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4944 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4945 } else if (!strcmp (opt, "check-scan-starts")) {
4946 do_scan_starts_check = TRUE;
4947 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4948 do_verify_nursery = TRUE;
4949 } else if (!strcmp (opt, "check-concurrent")) {
4950 if (!major_collector.is_concurrent) {
4951 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4954 do_concurrent_checks = TRUE;
4955 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4956 do_dump_nursery_content = TRUE;
4957 } else if (!strcmp (opt, "no-managed-allocator")) {
4958 sgen_set_use_managed_allocator (FALSE);
4959 } else if (!strcmp (opt, "disable-minor")) {
4960 disable_minor_collections = TRUE;
4961 } else if (!strcmp (opt, "disable-major")) {
4962 disable_major_collections = TRUE;
4963 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4964 char *filename = strchr (opt, '=') + 1;
4965 nursery_clear_policy = CLEAR_AT_GC;
4966 heap_dump_file = fopen (filename, "w");
4967 if (heap_dump_file) {
4968 fprintf (heap_dump_file, "<sgen-dump>\n");
4969 do_pin_stats = TRUE;
4971 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4972 char *filename = strchr (opt, '=') + 1;
4973 char *colon = strrchr (filename, ':');
4976 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
4977 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
4982 binary_protocol_init (filename, (long long)limit);
4983 } else if (!strcmp (opt, "nursery-canaries")) {
4984 do_verify_nursery = TRUE;
4985 sgen_set_use_managed_allocator (FALSE);
4986 enable_nursery_canaries = TRUE;
4987 } else if (!sgen_bridge_handle_gc_debug (opt)) {
4988 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4993 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);
4994 fprintf (stderr, "Valid <option>s are:\n");
4995 fprintf (stderr, " collect-before-allocs[=<n>]\n");
4996 fprintf (stderr, " verify-before-allocs[=<n>]\n");
4997 fprintf (stderr, " check-at-minor-collections\n");
4998 fprintf (stderr, " check-mark-bits\n");
4999 fprintf (stderr, " check-nursery-pinned\n");
5000 fprintf (stderr, " verify-before-collections\n");
5001 fprintf (stderr, " verify-nursery-at-minor-gc\n");
5002 fprintf (stderr, " dump-nursery-at-minor-gc\n");
5003 fprintf (stderr, " disable-minor\n");
5004 fprintf (stderr, " disable-major\n");
5005 fprintf (stderr, " xdomain-checks\n");
5006 fprintf (stderr, " check-concurrent\n");
5007 fprintf (stderr, " clear-[nursery-]at-gc\n");
5008 fprintf (stderr, " clear-at-tlab-creation\n");
5009 fprintf (stderr, " debug-clear-at-tlab-creation\n");
5010 fprintf (stderr, " check-scan-starts\n");
5011 fprintf (stderr, " no-managed-allocator\n");
5012 fprintf (stderr, " print-allowance\n");
5013 fprintf (stderr, " print-pinning\n");
5014 fprintf (stderr, " heap-dump=<filename>\n");
5015 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
5016 fprintf (stderr, " nursery-canaries\n");
5017 sgen_bridge_print_gc_debug_usage ();
5018 fprintf (stderr, "\n");
5020 usage_printed = TRUE;
5026 if (major_collector.post_param_init)
5027 major_collector.post_param_init (&major_collector);
5029 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
5031 memset (&remset, 0, sizeof (remset));
5033 sgen_card_table_init (&remset);
5039 mono_gc_get_gc_name (void)
5044 static MonoMethod *write_barrier_method;
5047 sgen_is_critical_method (MonoMethod *method)
5049 return (method == write_barrier_method || sgen_is_managed_allocator (method));
5053 sgen_has_critical_method (void)
5055 return write_barrier_method || sgen_has_managed_allocator ();
5061 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels)
5063 memset (nursery_check_return_labels, 0, sizeof (int) * 3);
5064 #ifdef SGEN_ALIGN_NURSERY
5065 // if (ptr_in_nursery (ptr)) return;
5067 * Masking out the bits might be faster, but we would have to use 64 bit
5068 * immediates, which might be slower.
5070 mono_mb_emit_ldarg (mb, 0);
5071 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5072 mono_mb_emit_byte (mb, CEE_SHR_UN);
5073 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5074 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5076 if (!major_collector.is_concurrent) {
5077 // if (!ptr_in_nursery (*ptr)) return;
5078 mono_mb_emit_ldarg (mb, 0);
5079 mono_mb_emit_byte (mb, CEE_LDIND_I);
5080 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5081 mono_mb_emit_byte (mb, CEE_SHR_UN);
5082 mono_mb_emit_ptr (mb, (gpointer)((mword)sgen_get_nursery_start () >> DEFAULT_NURSERY_BITS));
5083 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5086 int label_continue1, label_continue2;
5087 int dereferenced_var;
5089 // if (ptr < (sgen_get_nursery_start ())) goto continue;
5090 mono_mb_emit_ldarg (mb, 0);
5091 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5092 label_continue_1 = mono_mb_emit_branch (mb, CEE_BLT);
5094 // if (ptr >= sgen_get_nursery_end ())) goto continue;
5095 mono_mb_emit_ldarg (mb, 0);
5096 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5097 label_continue_2 = mono_mb_emit_branch (mb, CEE_BGE);
5100 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BR);
5103 mono_mb_patch_branch (mb, label_continue_1);
5104 mono_mb_patch_branch (mb, label_continue_2);
5106 // Dereference and store in local var
5107 dereferenced_var = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
5108 mono_mb_emit_ldarg (mb, 0);
5109 mono_mb_emit_byte (mb, CEE_LDIND_I);
5110 mono_mb_emit_stloc (mb, dereferenced_var);
5112 if (!major_collector.is_concurrent) {
5113 // if (*ptr < sgen_get_nursery_start ()) return;
5114 mono_mb_emit_ldloc (mb, dereferenced_var);
5115 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_start ());
5116 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BLT);
5118 // if (*ptr >= sgen_get_nursery_end ()) return;
5119 mono_mb_emit_ldloc (mb, dereferenced_var);
5120 mono_mb_emit_ptr (mb, (gpointer) sgen_get_nursery_end ());
5121 nursery_check_return_labels [2] = mono_mb_emit_branch (mb, CEE_BGE);
5128 mono_gc_get_write_barrier (void)
5131 MonoMethodBuilder *mb;
5132 MonoMethodSignature *sig;
5133 #ifdef MANAGED_WBARRIER
5134 int i, nursery_check_labels [3];
5136 #ifdef HAVE_KW_THREAD
5137 int stack_end_offset = -1;
5139 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5140 g_assert (stack_end_offset != -1);
5144 // FIXME: Maybe create a separate version for ctors (the branch would be
5145 // correctly predicted more times)
5146 if (write_barrier_method)
5147 return write_barrier_method;
5149 /* Create the IL version of mono_gc_barrier_generic_store () */
5150 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5151 sig->ret = &mono_defaults.void_class->byval_arg;
5152 sig->params [0] = &mono_defaults.int_class->byval_arg;
5154 mb = mono_mb_new (mono_defaults.object_class, "wbarrier", MONO_WRAPPER_WRITE_BARRIER);
5157 #ifdef MANAGED_WBARRIER
5158 emit_nursery_check (mb, nursery_check_labels);
5160 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5164 LDC_PTR sgen_cardtable
5166 address >> CARD_BITS
5170 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5171 LDC_PTR card_table_mask
5178 mono_mb_emit_ptr (mb, sgen_cardtable);
5179 mono_mb_emit_ldarg (mb, 0);
5180 mono_mb_emit_icon (mb, CARD_BITS);
5181 mono_mb_emit_byte (mb, CEE_SHR_UN);
5182 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5183 mono_mb_emit_ptr (mb, (gpointer)CARD_MASK);
5184 mono_mb_emit_byte (mb, CEE_AND);
5186 mono_mb_emit_byte (mb, CEE_ADD);
5187 mono_mb_emit_icon (mb, 1);
5188 mono_mb_emit_byte (mb, CEE_STIND_I1);
5191 for (i = 0; i < 3; ++i) {
5192 if (nursery_check_labels [i])
5193 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5195 mono_mb_emit_byte (mb, CEE_RET);
5197 mono_mb_emit_ldarg (mb, 0);
5198 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5199 mono_mb_emit_byte (mb, CEE_RET);
5202 res = mono_mb_create_method (mb, sig, 16);
5206 if (write_barrier_method) {
5207 /* Already created */
5208 mono_free_method (res);
5210 /* double-checked locking */
5211 mono_memory_barrier ();
5212 write_barrier_method = res;
5216 return write_barrier_method;
5220 mono_gc_get_description (void)
5222 return g_strdup ("sgen");
5226 mono_gc_set_desktop_mode (void)
5231 mono_gc_is_moving (void)
5237 mono_gc_is_disabled (void)
5243 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5250 sgen_get_nursery_clear_policy (void)
5252 return nursery_clear_policy;
5256 sgen_get_array_fill_vtable (void)
5258 if (!array_fill_vtable) {
5259 static MonoClass klass;
5260 static MonoVTable vtable;
5263 MonoDomain *domain = mono_get_root_domain ();
5266 klass.element_class = mono_defaults.byte_class;
5268 klass.instance_size = sizeof (MonoArray);
5269 klass.sizes.element_size = 1;
5270 klass.name = "array_filler_type";
5272 vtable.klass = &klass;
5274 vtable.gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5277 array_fill_vtable = &vtable;
5279 return array_fill_vtable;
5289 sgen_gc_unlock (void)
5291 gboolean try_free = sgen_try_free_some_memory;
5292 sgen_try_free_some_memory = FALSE;
5293 mono_mutex_unlock (&gc_mutex);
5294 MONO_GC_UNLOCKED ();
5296 mono_thread_hazardous_try_free_some ();
5300 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5302 major_collector.iterate_live_block_ranges (callback);
5306 sgen_major_collector_scan_card_table (SgenGrayQueue *queue)
5308 major_collector.scan_card_table (FALSE, queue);
5312 sgen_get_major_collector (void)
5314 return &major_collector;
5317 void mono_gc_set_skip_thread (gboolean skip)
5319 SgenThreadInfo *info = mono_thread_info_current ();
5322 info->gc_disabled = skip;
5327 sgen_get_remset (void)
5333 mono_gc_get_vtable_bits (MonoClass *class)
5336 /* FIXME move this to the bridge code */
5337 if (sgen_need_bridge_processing ()) {
5338 switch (sgen_bridge_class_kind (class)) {
5339 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5340 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5341 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5343 case GC_BRIDGE_OPAQUE_CLASS:
5344 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5348 if (fin_callbacks.is_class_finalization_aware) {
5349 if (fin_callbacks.is_class_finalization_aware (class))
5350 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5356 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5363 sgen_check_whole_heap_stw (void)
5365 sgen_stop_world (0);
5366 sgen_clear_nursery_fragments ();
5367 sgen_check_whole_heap (FALSE);
5368 sgen_restart_world (0, NULL);
5372 sgen_gc_event_moves (void)
5374 if (moved_objects_idx) {
5375 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5376 moved_objects_idx = 0;
5381 sgen_timestamp (void)
5383 SGEN_TV_DECLARE (timestamp);
5384 SGEN_TV_GETTIME (timestamp);
5385 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5389 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5391 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5392 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5394 fin_callbacks = *callbacks;
5401 #endif /* HAVE_SGEN_GC */