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 nursery_collection_is_parallel = FALSE;
289 static gboolean disable_minor_collections = FALSE;
290 static gboolean disable_major_collections = FALSE;
291 gboolean do_pin_stats = FALSE;
292 static gboolean do_verify_nursery = FALSE;
293 static gboolean do_dump_nursery_content = 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 int stat_minor_gcs = 0;
326 int stat_major_gcs = 0;
328 static long long stat_pinned_objects = 0;
330 static long long time_minor_pre_collection_fragment_clear = 0;
331 static long long time_minor_pinning = 0;
332 static long long time_minor_scan_remsets = 0;
333 static long long time_minor_scan_pinned = 0;
334 static long long time_minor_scan_registered_roots = 0;
335 static long long time_minor_scan_thread_data = 0;
336 static long long time_minor_finish_gray_stack = 0;
337 static long long time_minor_fragment_creation = 0;
339 static long long time_major_pre_collection_fragment_clear = 0;
340 static long long time_major_pinning = 0;
341 static long long time_major_scan_pinned = 0;
342 static long long time_major_scan_registered_roots = 0;
343 static long long time_major_scan_thread_data = 0;
344 static long long time_major_scan_alloc_pinned = 0;
345 static long long time_major_scan_finalized = 0;
346 static long long time_major_scan_big_objects = 0;
347 static long long time_major_finish_gray_stack = 0;
348 static long long time_major_free_bigobjs = 0;
349 static long long time_major_los_sweep = 0;
350 static long long time_major_sweep = 0;
351 static long long time_major_fragment_creation = 0;
353 int gc_debug_level = 0;
356 static MonoGCFinalizerCallbacks fin_callbacks;
360 mono_gc_flush_info (void)
362 fflush (gc_debug_file);
366 #define TV_DECLARE SGEN_TV_DECLARE
367 #define TV_GETTIME SGEN_TV_GETTIME
368 #define TV_ELAPSED SGEN_TV_ELAPSED
369 #define TV_ELAPSED_MS SGEN_TV_ELAPSED_MS
371 SGEN_TV_DECLARE (sgen_init_timestamp);
373 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
375 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
377 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
378 #define object_is_pinned SGEN_OBJECT_IS_PINNED
379 #define pin_object SGEN_PIN_OBJECT
380 #define unpin_object SGEN_UNPIN_OBJECT
382 #define ptr_in_nursery sgen_ptr_in_nursery
384 #define LOAD_VTABLE SGEN_LOAD_VTABLE
387 safe_name (void* obj)
389 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
390 return vt->klass->name;
393 #define safe_object_get_size sgen_safe_object_get_size
396 sgen_safe_name (void* obj)
398 return safe_name (obj);
402 * ######################################################################
403 * ######## Global data.
404 * ######################################################################
406 LOCK_DECLARE (gc_mutex);
407 gboolean sgen_try_free_some_memory;
409 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
411 static mword pagesize = 4096;
412 size_t degraded_mode = 0;
414 static mword bytes_pinned_from_failed_allocation = 0;
416 GCMemSection *nursery_section = NULL;
417 static mword lowest_heap_address = ~(mword)0;
418 static mword highest_heap_address = 0;
420 LOCK_DECLARE (sgen_interruption_mutex);
421 static LOCK_DECLARE (pin_queue_mutex);
423 #define LOCK_PIN_QUEUE mono_mutex_lock (&pin_queue_mutex)
424 #define UNLOCK_PIN_QUEUE mono_mutex_unlock (&pin_queue_mutex)
426 typedef struct _FinalizeReadyEntry FinalizeReadyEntry;
427 struct _FinalizeReadyEntry {
428 FinalizeReadyEntry *next;
432 typedef struct _EphemeronLinkNode EphemeronLinkNode;
434 struct _EphemeronLinkNode {
435 EphemeronLinkNode *next;
444 int current_collection_generation = -1;
445 volatile gboolean concurrent_collection_in_progress = FALSE;
447 /* objects that are ready to be finalized */
448 static FinalizeReadyEntry *fin_ready_list = NULL;
449 static FinalizeReadyEntry *critical_fin_list = NULL;
451 static EphemeronLinkNode *ephemeron_list;
453 /* registered roots: the key to the hash is the root start address */
455 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
457 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
458 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
459 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL),
460 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), mono_aligned_addr_hash, NULL)
462 static mword roots_size = 0; /* amount of memory in the root set */
464 #define GC_ROOT_NUM 32
466 int count; /* must be the first field */
467 void *objects [GC_ROOT_NUM];
468 int root_types [GC_ROOT_NUM];
469 uintptr_t extra_info [GC_ROOT_NUM];
473 notify_gc_roots (GCRootReport *report)
477 mono_profiler_gc_roots (report->count, report->objects, report->root_types, report->extra_info);
482 add_profile_gc_root (GCRootReport *report, void *object, int rtype, uintptr_t extra_info)
484 if (report->count == GC_ROOT_NUM)
485 notify_gc_roots (report);
486 report->objects [report->count] = object;
487 report->root_types [report->count] = rtype;
488 report->extra_info [report->count++] = (uintptr_t)((MonoVTable*)LOAD_VTABLE (object))->klass;
491 MonoNativeTlsKey thread_info_key;
493 #ifdef HAVE_KW_THREAD
494 __thread SgenThreadInfo *sgen_thread_info;
495 __thread char *stack_end;
498 /* The size of a TLAB */
499 /* The bigger the value, the less often we have to go to the slow path to allocate a new
500 * one, but the more space is wasted by threads not allocating much memory.
502 * FIXME: Make this self-tuning for each thread.
504 guint32 tlab_size = (1024 * 4);
506 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
508 /* Functions supplied by the runtime to be called by the GC */
509 static MonoGCCallbacks gc_callbacks;
511 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
512 #define ALLOC_ALIGN_BITS SGEN_ALLOC_ALIGN_BITS
514 #define ALIGN_UP SGEN_ALIGN_UP
516 #define MOVED_OBJECTS_NUM 64
517 static void *moved_objects [MOVED_OBJECTS_NUM];
518 static int moved_objects_idx = 0;
520 /* Vtable of the objects used to fill out nursery fragments before a collection */
521 static MonoVTable *array_fill_vtable;
523 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
524 MonoNativeThreadId main_gc_thread = NULL;
527 /*Object was pinned during the current collection*/
528 static mword objects_pinned;
531 * ######################################################################
532 * ######## Macros and function declarations.
533 * ######################################################################
537 align_pointer (void *ptr)
539 mword p = (mword)ptr;
540 p += sizeof (gpointer) - 1;
541 p &= ~ (sizeof (gpointer) - 1);
545 typedef SgenGrayQueue GrayQueue;
547 /* forward declarations */
548 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue);
549 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
550 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
551 static void report_finalizer_roots (void);
552 static void report_registered_roots (void);
554 static void pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue);
555 static int pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx);
556 static void finish_gray_stack (int generation, GrayQueue *queue);
558 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
561 static void init_stats (void);
563 static int mark_ephemerons_in_range (ScanCopyContext ctx);
564 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
565 static void null_ephemerons_for_domain (MonoDomain *domain);
567 static gboolean major_update_or_finish_concurrent_collection (gboolean force_finish);
569 SgenObjectOperations current_object_ops;
570 SgenMajorCollector major_collector;
571 SgenMinorCollector sgen_minor_collector;
572 static GrayQueue gray_queue;
574 static SgenRemeberedSet remset;
576 /* The gray queue to use from the main collection thread. */
577 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
580 * The gray queue a worker job must use. If we're not parallel or
581 * concurrent, we use the main gray queue.
583 static SgenGrayQueue*
584 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
586 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
590 gray_queue_redirect (SgenGrayQueue *queue)
592 gboolean wake = FALSE;
596 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
599 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
604 g_assert (concurrent_collection_in_progress ||
605 (current_collection_generation == GENERATION_OLD && major_collector.is_parallel));
606 if (sgen_workers_have_started ()) {
607 sgen_workers_wake_up_all ();
609 if (concurrent_collection_in_progress)
610 g_assert (current_collection_generation == -1);
616 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
618 while (start < end) {
622 if (!*(void**)start) {
623 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
628 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
634 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
636 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable)
637 callback (obj, size, data);
644 need_remove_object_for_domain (char *start, MonoDomain *domain)
646 if (mono_object_domain (start) == domain) {
647 SGEN_LOG (4, "Need to cleanup object %p", start);
648 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
655 process_object_for_domain_clearing (char *start, MonoDomain *domain)
657 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
658 if (vt->klass == mono_defaults.internal_thread_class)
659 g_assert (mono_object_domain (start) == mono_get_root_domain ());
660 /* The object could be a proxy for an object in the domain
662 #ifndef DISABLE_REMOTING
663 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
664 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
666 /* The server could already have been zeroed out, so
667 we need to check for that, too. */
668 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
669 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
670 ((MonoRealProxy*)start)->unwrapped_server = NULL;
677 clear_domain_process_object (char *obj, MonoDomain *domain)
681 process_object_for_domain_clearing (obj, domain);
682 remove = need_remove_object_for_domain (obj, domain);
684 if (remove && ((MonoObject*)obj)->synchronisation) {
685 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
687 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
694 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
696 if (clear_domain_process_object (obj, domain))
697 memset (obj, 0, size);
701 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
703 clear_domain_process_object (obj, domain);
707 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
709 if (need_remove_object_for_domain (obj, domain))
710 major_collector.free_non_pinned_object (obj, size);
714 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
716 if (need_remove_object_for_domain (obj, domain))
717 major_collector.free_pinned_object (obj, size);
721 * When appdomains are unloaded we can easily remove objects that have finalizers,
722 * but all the others could still be present in random places on the heap.
723 * We need a sweep to get rid of them even though it's going to be costly
725 * The reason we need to remove them is because we access the vtable and class
726 * structures to know the object size and the reference bitmap: once the domain is
727 * unloaded the point to random memory.
730 mono_gc_clear_domain (MonoDomain * domain)
732 LOSObject *bigobj, *prev;
737 binary_protocol_domain_unload_begin (domain);
741 if (concurrent_collection_in_progress)
742 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
743 g_assert (!concurrent_collection_in_progress);
745 sgen_process_fin_stage_entries ();
746 sgen_process_dislink_stage_entries ();
748 sgen_clear_nursery_fragments ();
750 if (xdomain_checks && domain != mono_get_root_domain ()) {
751 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
752 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
753 sgen_check_for_xdomain_refs ();
756 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
757 to memory returned to the OS.*/
758 null_ephemerons_for_domain (domain);
760 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
761 sgen_null_links_for_domain (domain, i);
763 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
764 sgen_remove_finalizers_for_domain (domain, i);
766 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
767 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
769 /* We need two passes over major and large objects because
770 freeing such objects might give their memory back to the OS
771 (in the case of large objects) or obliterate its vtable
772 (pinned objects with major-copying or pinned and non-pinned
773 objects with major-mark&sweep), but we might need to
774 dereference a pointer from an object to another object if
775 the first object is a proxy. */
776 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
777 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
778 clear_domain_process_object (bigobj->data, domain);
781 for (bigobj = los_object_list; bigobj;) {
782 if (need_remove_object_for_domain (bigobj->data, domain)) {
783 LOSObject *to_free = bigobj;
785 prev->next = bigobj->next;
787 los_object_list = bigobj->next;
788 bigobj = bigobj->next;
789 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
790 sgen_los_free_object (to_free);
794 bigobj = bigobj->next;
796 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
797 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
799 if (domain == mono_get_root_domain ()) {
800 if (G_UNLIKELY (do_pin_stats))
801 sgen_pin_stats_print_class_stats ();
802 sgen_object_layout_dump (stdout);
805 sgen_restart_world (0, NULL);
807 binary_protocol_domain_unload_end (domain);
813 * sgen_add_to_global_remset:
815 * The global remset contains locations which point into newspace after
816 * a minor collection. This can happen if the objects they point to are pinned.
818 * LOCKING: If called from a parallel collector, the global remset
819 * lock must be held. For serial collectors that is not necessary.
822 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
824 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
826 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
828 if (!major_collector.is_concurrent) {
829 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
831 if (current_collection_generation == -1)
832 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
835 if (!object_is_pinned (obj))
836 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");
837 else if (sgen_cement_lookup_or_register (obj))
840 remset.record_pointer (ptr);
842 if (G_UNLIKELY (do_pin_stats))
843 sgen_pin_stats_register_global_remset (obj);
845 SGEN_LOG (8, "Adding global remset for %p", ptr);
846 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
850 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
851 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
852 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
853 vt->klass->name_space, vt->klass->name);
859 * sgen_drain_gray_stack:
861 * Scan objects in the gray stack until the stack is empty. This should be called
862 * frequently after each object is copied, to achieve better locality and cache
866 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
869 ScanObjectFunc scan_func = ctx.scan_func;
870 GrayQueue *queue = ctx.queue;
872 if (max_objs == -1) {
874 GRAY_OBJECT_DEQUEUE (queue, obj);
877 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
878 scan_func (obj, queue);
884 for (i = 0; i != max_objs; ++i) {
885 GRAY_OBJECT_DEQUEUE (queue, obj);
888 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
889 scan_func (obj, queue);
891 } while (max_objs < 0);
897 * Addresses from start to end are already sorted. This function finds
898 * the object header for each address and pins the object. The
899 * addresses must be inside the passed section. The (start of the)
900 * address array is overwritten with the addresses of the actually
901 * pinned objects. Return the number of pinned objects.
904 pin_objects_from_addresses (GCMemSection *section, void **start, void **end, void *start_nursery, void *end_nursery, ScanCopyContext ctx)
909 void *last_obj = NULL;
910 size_t last_obj_size = 0;
913 void **definitely_pinned = start;
914 ScanObjectFunc scan_func = ctx.scan_func;
915 SgenGrayQueue *queue = ctx.queue;
917 sgen_nursery_allocator_prepare_for_pinning ();
919 while (start < end) {
921 /* the range check should be reduntant */
922 if (addr != last && addr >= start_nursery && addr < end_nursery) {
923 SGEN_LOG (5, "Considering pinning addr %p", addr);
924 /* multiple pointers to the same object */
925 if (addr >= last_obj && (char*)addr < (char*)last_obj + last_obj_size) {
929 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
930 g_assert (idx < section->num_scan_start);
931 search_start = (void*)section->scan_starts [idx];
932 if (!search_start || search_start > addr) {
935 search_start = section->scan_starts [idx];
936 if (search_start && search_start <= addr)
939 if (!search_start || search_start > addr)
940 search_start = start_nursery;
942 if (search_start < last_obj)
943 search_start = (char*)last_obj + last_obj_size;
944 /* now addr should be in an object a short distance from search_start
945 * Note that search_start must point to zeroed mem or point to an object.
949 if (!*(void**)search_start) {
950 /* Consistency check */
952 for (frag = nursery_fragments; frag; frag = frag->next) {
953 if (search_start >= frag->fragment_start && search_start < frag->fragment_end)
954 g_assert_not_reached ();
958 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
961 last_obj = search_start;
962 last_obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
964 if (((MonoObject*)last_obj)->synchronisation == GINT_TO_POINTER (-1)) {
965 /* Marks the beginning of a nursery fragment, skip */
967 SGEN_LOG (8, "Pinned try match %p (%s), size %zd", last_obj, safe_name (last_obj), last_obj_size);
968 if (addr >= search_start && (char*)addr < (char*)last_obj + last_obj_size) {
970 scan_func (search_start, queue);
972 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
973 search_start, *(void**)search_start, safe_name (search_start), count);
974 binary_protocol_pin (search_start,
975 (gpointer)LOAD_VTABLE (search_start),
976 safe_object_get_size (search_start));
979 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
980 int gen = sgen_ptr_in_nursery (search_start) ? GENERATION_NURSERY : GENERATION_OLD;
981 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (search_start);
982 MONO_GC_OBJ_PINNED ((mword)search_start,
983 sgen_safe_object_get_size (search_start),
984 vt->klass->name_space, vt->klass->name, gen);
988 pin_object (search_start);
989 GRAY_OBJECT_ENQUEUE (queue, search_start);
990 if (G_UNLIKELY (do_pin_stats))
991 sgen_pin_stats_register_object (search_start, last_obj_size);
992 definitely_pinned [count] = search_start;
998 /* skip to the next object */
999 search_start = (void*)((char*)search_start + last_obj_size);
1000 } while (search_start <= addr);
1001 /* we either pinned the correct object or we ignored the addr because
1002 * it points to unused zeroed memory.
1008 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1009 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1010 GCRootReport report;
1012 for (idx = 0; idx < count; ++idx)
1013 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1014 notify_gc_roots (&report);
1016 stat_pinned_objects += count;
1021 sgen_pin_objects_in_section (GCMemSection *section, ScanCopyContext ctx)
1023 size_t num_entries = section->pin_queue_num_entries;
1025 void **start = section->pin_queue_start;
1027 reduced_to = pin_objects_from_addresses (section, start, start + num_entries,
1028 section->data, section->next_data, ctx);
1029 section->pin_queue_num_entries = reduced_to;
1031 section->pin_queue_start = NULL;
1037 sgen_pin_object (void *object, GrayQueue *queue)
1039 g_assert (!concurrent_collection_in_progress);
1041 if (sgen_collection_is_parallel ()) {
1043 /*object arrives pinned*/
1044 sgen_pin_stage_ptr (object);
1048 SGEN_PIN_OBJECT (object);
1049 sgen_pin_stage_ptr (object);
1051 if (G_UNLIKELY (do_pin_stats))
1052 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1054 GRAY_OBJECT_ENQUEUE (queue, object);
1055 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1057 #ifdef ENABLE_DTRACE
1058 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1059 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1060 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1061 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1067 sgen_parallel_pin_or_update (void **ptr, void *obj, MonoVTable *vt, SgenGrayQueue *queue)
1071 gboolean major_pinned = FALSE;
1073 if (sgen_ptr_in_nursery (obj)) {
1074 if (SGEN_CAS_PTR (obj, (void*)((mword)vt | SGEN_PINNED_BIT), vt) == vt) {
1075 sgen_pin_object (obj, queue);
1079 major_collector.pin_major_object (obj, queue);
1080 major_pinned = TRUE;
1083 vtable_word = *(mword*)obj;
1084 /*someone else forwarded it, update the pointer and bail out*/
1085 if (vtable_word & SGEN_FORWARDED_BIT) {
1086 *ptr = (void*)(vtable_word & ~SGEN_VTABLE_BITS_MASK);
1090 /*someone pinned it, nothing to do.*/
1091 if (vtable_word & SGEN_PINNED_BIT || major_pinned)
1096 /* Sort the addresses in array in increasing order.
1097 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1100 sgen_sort_addresses (void **array, size_t size)
1105 for (i = 1; i < size; ++i) {
1108 size_t parent = (child - 1) / 2;
1110 if (array [parent] >= array [child])
1113 tmp = array [parent];
1114 array [parent] = array [child];
1115 array [child] = tmp;
1121 for (i = size - 1; i > 0; --i) {
1124 array [i] = array [0];
1130 while (root * 2 + 1 <= end) {
1131 size_t child = root * 2 + 1;
1133 if (child < end && array [child] < array [child + 1])
1135 if (array [root] >= array [child])
1139 array [root] = array [child];
1140 array [child] = tmp;
1148 * Scan the memory between start and end and queue values which could be pointers
1149 * to the area between start_nursery and end_nursery for later consideration.
1150 * Typically used for thread stacks.
1153 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1157 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1158 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1161 while (start < end) {
1162 if (*start >= start_nursery && *start < end_nursery) {
1164 * *start can point to the middle of an object
1165 * note: should we handle pointing at the end of an object?
1166 * pinning in C# code disallows pointing at the end of an object
1167 * but there is some small chance that an optimizing C compiler
1168 * may keep the only reference to an object by pointing
1169 * at the end of it. We ignore this small chance for now.
1170 * Pointers to the end of an object are indistinguishable
1171 * from pointers to the start of the next object in memory
1172 * so if we allow that we'd need to pin two objects...
1173 * We queue the pointer in an array, the
1174 * array will then be sorted and uniqued. This way
1175 * we can coalesce several pinning pointers and it should
1176 * be faster since we'd do a memory scan with increasing
1177 * addresses. Note: we can align the address to the allocation
1178 * alignment, so the unique process is more effective.
1180 mword addr = (mword)*start;
1181 addr &= ~(ALLOC_ALIGN - 1);
1182 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1183 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1184 sgen_pin_stage_ptr ((void*)addr);
1187 if (G_UNLIKELY (do_pin_stats)) {
1188 if (ptr_in_nursery ((void*)addr))
1189 sgen_pin_stats_register_address ((char*)addr, pin_type);
1195 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1199 * The first thing we do in a collection is to identify pinned objects.
1200 * This function considers all the areas of memory that need to be
1201 * conservatively scanned.
1204 pin_from_roots (void *start_nursery, void *end_nursery, GrayQueue *queue)
1208 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);
1209 /* objects pinned from the API are inside these roots */
1210 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1211 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1212 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1213 } SGEN_HASH_TABLE_FOREACH_END;
1214 /* now deal with the thread stacks
1215 * in the future we should be able to conservatively scan only:
1216 * *) the cpu registers
1217 * *) the unmanaged stack frames
1218 * *) the _last_ managed stack frame
1219 * *) pointers slots in managed frames
1221 scan_thread_data (start_nursery, end_nursery, FALSE, queue);
1225 unpin_objects_from_queue (SgenGrayQueue *queue)
1229 GRAY_OBJECT_DEQUEUE (queue, addr);
1232 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1233 SGEN_UNPIN_OBJECT (addr);
1238 CopyOrMarkObjectFunc func;
1240 } UserCopyOrMarkData;
1242 static MonoNativeTlsKey user_copy_or_mark_key;
1245 init_user_copy_or_mark_key (void)
1247 mono_native_tls_alloc (&user_copy_or_mark_key, NULL);
1251 set_user_copy_or_mark_data (UserCopyOrMarkData *data)
1253 mono_native_tls_set_value (user_copy_or_mark_key, data);
1257 single_arg_user_copy_or_mark (void **obj)
1259 UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
1261 data->func (obj, data->queue);
1265 * The memory area from start_root to end_root contains pointers to objects.
1266 * Their position is precisely described by @desc (this means that the pointer
1267 * can be either NULL or the pointer to the start of an object).
1268 * This functions copies them to to_space updates them.
1270 * This function is not thread-safe!
1273 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1275 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1276 SgenGrayQueue *queue = ctx.queue;
1278 switch (desc & ROOT_DESC_TYPE_MASK) {
1279 case ROOT_DESC_BITMAP:
1280 desc >>= ROOT_DESC_TYPE_SHIFT;
1282 if ((desc & 1) && *start_root) {
1283 copy_func (start_root, queue);
1284 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1285 sgen_drain_gray_stack (-1, ctx);
1291 case ROOT_DESC_COMPLEX: {
1292 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1293 gsize bwords = (*bitmap_data) - 1;
1294 void **start_run = start_root;
1296 while (bwords-- > 0) {
1297 gsize bmap = *bitmap_data++;
1298 void **objptr = start_run;
1300 if ((bmap & 1) && *objptr) {
1301 copy_func (objptr, queue);
1302 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1303 sgen_drain_gray_stack (-1, ctx);
1308 start_run += GC_BITS_PER_WORD;
1312 case ROOT_DESC_USER: {
1313 UserCopyOrMarkData data = { copy_func, queue };
1314 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1315 set_user_copy_or_mark_data (&data);
1316 marker (start_root, single_arg_user_copy_or_mark);
1317 set_user_copy_or_mark_data (NULL);
1320 case ROOT_DESC_RUN_LEN:
1321 g_assert_not_reached ();
1323 g_assert_not_reached ();
1328 reset_heap_boundaries (void)
1330 lowest_heap_address = ~(mword)0;
1331 highest_heap_address = 0;
1335 sgen_update_heap_boundaries (mword low, mword high)
1340 old = lowest_heap_address;
1343 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1346 old = highest_heap_address;
1349 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1353 * Allocate and setup the data structures needed to be able to allocate objects
1354 * in the nursery. The nursery is stored in nursery_section.
1357 alloc_nursery (void)
1359 GCMemSection *section;
1364 if (nursery_section)
1366 SGEN_LOG (2, "Allocating nursery size: %lu", (size_t)sgen_nursery_size);
1367 /* later we will alloc a larger area for the nursery but only activate
1368 * what we need. The rest will be used as expansion if we have too many pinned
1369 * objects in the existing nursery.
1371 /* FIXME: handle OOM */
1372 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1374 alloc_size = sgen_nursery_size;
1376 /* If there isn't enough space even for the nursery we should simply abort. */
1377 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1379 #ifdef SGEN_ALIGN_NURSERY
1380 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1382 data = major_collector.alloc_heap (alloc_size, 0, DEFAULT_NURSERY_BITS);
1384 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1385 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 ());
1386 section->data = section->next_data = data;
1387 section->size = alloc_size;
1388 section->end_data = data + sgen_nursery_size;
1389 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1390 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1391 section->num_scan_start = scan_starts;
1393 nursery_section = section;
1395 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1399 mono_gc_get_nursery (int *shift_bits, size_t *size)
1401 *size = sgen_nursery_size;
1402 #ifdef SGEN_ALIGN_NURSERY
1403 *shift_bits = DEFAULT_NURSERY_BITS;
1407 return sgen_get_nursery_start ();
1411 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1413 SgenThreadInfo *info = mono_thread_info_current ();
1415 /* Could be called from sgen_thread_unregister () with a NULL info */
1418 info->stopped_domain = domain;
1423 mono_gc_precise_stack_mark_enabled (void)
1425 return !conservative_stack_mark;
1429 mono_gc_get_logfile (void)
1431 return gc_debug_file;
1435 report_finalizer_roots_list (FinalizeReadyEntry *list)
1437 GCRootReport report;
1438 FinalizeReadyEntry *fin;
1441 for (fin = list; fin; fin = fin->next) {
1444 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1446 notify_gc_roots (&report);
1450 report_finalizer_roots (void)
1452 report_finalizer_roots_list (fin_ready_list);
1453 report_finalizer_roots_list (critical_fin_list);
1456 static GCRootReport *root_report;
1459 single_arg_report_root (void **obj)
1462 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1466 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1468 switch (desc & ROOT_DESC_TYPE_MASK) {
1469 case ROOT_DESC_BITMAP:
1470 desc >>= ROOT_DESC_TYPE_SHIFT;
1472 if ((desc & 1) && *start_root) {
1473 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1479 case ROOT_DESC_COMPLEX: {
1480 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1481 gsize bwords = (*bitmap_data) - 1;
1482 void **start_run = start_root;
1484 while (bwords-- > 0) {
1485 gsize bmap = *bitmap_data++;
1486 void **objptr = start_run;
1488 if ((bmap & 1) && *objptr) {
1489 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1494 start_run += GC_BITS_PER_WORD;
1498 case ROOT_DESC_USER: {
1499 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1500 root_report = report;
1501 marker (start_root, single_arg_report_root);
1504 case ROOT_DESC_RUN_LEN:
1505 g_assert_not_reached ();
1507 g_assert_not_reached ();
1512 report_registered_roots_by_type (int root_type)
1514 GCRootReport report;
1518 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1519 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1520 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1521 } SGEN_HASH_TABLE_FOREACH_END;
1522 notify_gc_roots (&report);
1526 report_registered_roots (void)
1528 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1529 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1533 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1535 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
1536 SgenGrayQueue *queue = ctx.queue;
1537 FinalizeReadyEntry *fin;
1539 for (fin = list; fin; fin = fin->next) {
1542 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1543 copy_func (&fin->object, queue);
1548 generation_name (int generation)
1550 switch (generation) {
1551 case GENERATION_NURSERY: return "nursery";
1552 case GENERATION_OLD: return "old";
1553 default: g_assert_not_reached ();
1558 sgen_generation_name (int generation)
1560 return generation_name (generation);
1563 SgenObjectOperations *
1564 sgen_get_current_object_ops (void){
1565 return ¤t_object_ops;
1570 finish_gray_stack (int generation, GrayQueue *queue)
1574 int done_with_ephemerons, ephemeron_rounds = 0;
1575 CopyOrMarkObjectFunc copy_func = current_object_ops.copy_or_mark_object;
1576 ScanObjectFunc scan_func = current_object_ops.scan_object;
1577 ScanCopyContext ctx = { scan_func, copy_func, queue };
1578 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1579 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1582 * We copied all the reachable objects. Now it's the time to copy
1583 * the objects that were not referenced by the roots, but by the copied objects.
1584 * we built a stack of objects pointed to by gray_start: they are
1585 * additional roots and we may add more items as we go.
1586 * We loop until gray_start == gray_objects which means no more objects have
1587 * been added. Note this is iterative: no recursion is involved.
1588 * We need to walk the LO list as well in search of marked big objects
1589 * (use a flag since this is needed only on major collections). We need to loop
1590 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1591 * To achieve better cache locality and cache usage, we drain the gray stack
1592 * frequently, after each object is copied, and just finish the work here.
1594 sgen_drain_gray_stack (-1, ctx);
1596 SGEN_LOG (2, "%s generation done", generation_name (generation));
1599 Reset bridge data, we might have lingering data from a previous collection if this is a major
1600 collection trigged by minor overflow.
1602 We must reset the gathered bridges since their original block might be evacuated due to major
1603 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1605 if (sgen_need_bridge_processing ())
1606 sgen_bridge_reset_data ();
1609 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1610 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1611 * objects that are in fact reachable.
1613 done_with_ephemerons = 0;
1615 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1616 sgen_drain_gray_stack (-1, ctx);
1618 } while (!done_with_ephemerons);
1620 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1622 if (sgen_need_bridge_processing ()) {
1623 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1624 sgen_drain_gray_stack (-1, ctx);
1625 sgen_collect_bridge_objects (generation, ctx);
1626 if (generation == GENERATION_OLD)
1627 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1630 Do the first bridge step here, as the collector liveness state will become useless after that.
1632 An important optimization is to only proccess the possibly dead part of the object graph and skip
1633 over all live objects as we transitively know everything they point must be alive too.
1635 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1637 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1638 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1641 sgen_bridge_processing_stw_step ();
1645 Make sure we drain the gray stack before processing disappearing links and finalizers.
1646 If we don't make sure it is empty we might wrongly see a live object as dead.
1648 sgen_drain_gray_stack (-1, ctx);
1651 We must clear weak links that don't track resurrection before processing object ready for
1652 finalization so they can be cleared before that.
1654 sgen_null_link_in_range (generation, TRUE, ctx);
1655 if (generation == GENERATION_OLD)
1656 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1659 /* walk the finalization queue and move also the objects that need to be
1660 * finalized: use the finalized objects as new roots so the objects they depend
1661 * on are also not reclaimed. As with the roots above, only objects in the nursery
1662 * are marked/copied.
1664 sgen_finalize_in_range (generation, ctx);
1665 if (generation == GENERATION_OLD)
1666 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1667 /* drain the new stack that might have been created */
1668 SGEN_LOG (6, "Precise scan of gray area post fin");
1669 sgen_drain_gray_stack (-1, ctx);
1672 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1674 done_with_ephemerons = 0;
1676 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1677 sgen_drain_gray_stack (-1, ctx);
1679 } while (!done_with_ephemerons);
1682 * Clear ephemeron pairs with unreachable keys.
1683 * We pass the copy func so we can figure out if an array was promoted or not.
1685 clear_unreachable_ephemerons (ctx);
1688 * We clear togglerefs only after all possible chances of revival are done.
1689 * This is semantically more inline with what users expect and it allows for
1690 * user finalizers to correctly interact with TR objects.
1692 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1695 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1698 * handle disappearing links
1699 * Note we do this after checking the finalization queue because if an object
1700 * survives (at least long enough to be finalized) we don't clear the link.
1701 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1702 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1705 g_assert (sgen_gray_object_queue_is_empty (queue));
1707 sgen_null_link_in_range (generation, FALSE, ctx);
1708 if (generation == GENERATION_OLD)
1709 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1710 if (sgen_gray_object_queue_is_empty (queue))
1712 sgen_drain_gray_stack (-1, ctx);
1715 g_assert (sgen_gray_object_queue_is_empty (queue));
1719 sgen_check_section_scan_starts (GCMemSection *section)
1722 for (i = 0; i < section->num_scan_start; ++i) {
1723 if (section->scan_starts [i]) {
1724 guint size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1725 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1731 check_scan_starts (void)
1733 if (!do_scan_starts_check)
1735 sgen_check_section_scan_starts (nursery_section);
1736 major_collector.check_scan_starts ();
1740 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1744 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1745 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1746 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1747 } SGEN_HASH_TABLE_FOREACH_END;
1751 sgen_dump_occupied (char *start, char *end, char *section_start)
1753 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1757 sgen_dump_section (GCMemSection *section, const char *type)
1759 char *start = section->data;
1760 char *end = section->data + section->size;
1761 char *occ_start = NULL;
1763 char *old_start = NULL; /* just for debugging */
1765 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1767 while (start < end) {
1771 if (!*(void**)start) {
1773 sgen_dump_occupied (occ_start, start, section->data);
1776 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1779 g_assert (start < section->next_data);
1784 vt = (GCVTable*)LOAD_VTABLE (start);
1787 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1790 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1791 start - section->data,
1792 vt->klass->name_space, vt->klass->name,
1800 sgen_dump_occupied (occ_start, start, section->data);
1802 fprintf (heap_dump_file, "</section>\n");
1806 dump_object (MonoObject *obj, gboolean dump_location)
1808 static char class_name [1024];
1810 MonoClass *class = mono_object_class (obj);
1814 * Python's XML parser is too stupid to parse angle brackets
1815 * in strings, so we just ignore them;
1818 while (class->name [i] && j < sizeof (class_name) - 1) {
1819 if (!strchr ("<>\"", class->name [i]))
1820 class_name [j++] = class->name [i];
1823 g_assert (j < sizeof (class_name));
1826 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%d\"",
1827 class->name_space, class_name,
1828 safe_object_get_size (obj));
1829 if (dump_location) {
1830 const char *location;
1831 if (ptr_in_nursery (obj))
1832 location = "nursery";
1833 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1837 fprintf (heap_dump_file, " location=\"%s\"", location);
1839 fprintf (heap_dump_file, "/>\n");
1843 dump_heap (const char *type, int num, const char *reason)
1848 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1850 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1851 fprintf (heap_dump_file, ">\n");
1852 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1853 sgen_dump_internal_mem_usage (heap_dump_file);
1854 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1855 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1856 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1858 fprintf (heap_dump_file, "<pinned-objects>\n");
1859 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1860 dump_object (list->obj, TRUE);
1861 fprintf (heap_dump_file, "</pinned-objects>\n");
1863 sgen_dump_section (nursery_section, "nursery");
1865 major_collector.dump_heap (heap_dump_file);
1867 fprintf (heap_dump_file, "<los>\n");
1868 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1869 dump_object ((MonoObject*)bigobj->data, FALSE);
1870 fprintf (heap_dump_file, "</los>\n");
1872 fprintf (heap_dump_file, "</collection>\n");
1876 sgen_register_moved_object (void *obj, void *destination)
1878 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1880 /* FIXME: handle this for parallel collector */
1881 g_assert (!sgen_collection_is_parallel ());
1883 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1884 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1885 moved_objects_idx = 0;
1887 moved_objects [moved_objects_idx++] = obj;
1888 moved_objects [moved_objects_idx++] = destination;
1894 static gboolean inited = FALSE;
1899 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1900 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_pinning);
1901 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1902 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1903 mono_counters_register ("Minor scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_registered_roots);
1904 mono_counters_register ("Minor scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_scan_thread_data);
1905 mono_counters_register ("Minor finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_finish_gray_stack);
1906 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1908 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1909 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_pinning);
1910 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1911 mono_counters_register ("Major scan registered roots", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_registered_roots);
1912 mono_counters_register ("Major scan thread data", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_thread_data);
1913 mono_counters_register ("Major scan alloc_pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_alloc_pinned);
1914 mono_counters_register ("Major scan finalized", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_finalized);
1915 mono_counters_register ("Major scan big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_scan_big_objects);
1916 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1917 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1918 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1919 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_sweep);
1920 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_LONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1922 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_pinned_objects);
1924 #ifdef HEAVY_STATISTICS
1925 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1926 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1927 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1928 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1929 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1930 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1931 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1932 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1933 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1935 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_alloced_degraded);
1936 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_bytes_alloced_degraded);
1938 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_nursery);
1939 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_nursery);
1940 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_copy_object_called_major);
1941 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_objects_copied_major);
1943 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_nursery);
1944 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_scan_object_called_major);
1946 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_slots_allocated_in_vain);
1948 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_from_space);
1949 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_forwarded);
1950 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_pinned);
1951 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_LONG, &stat_nursery_copy_object_failed_to_space);
1953 sgen_nursery_allocator_init_heavy_stats ();
1954 sgen_alloc_init_heavy_stats ();
1962 reset_pinned_from_failed_allocation (void)
1964 bytes_pinned_from_failed_allocation = 0;
1968 sgen_set_pinned_from_failed_allocation (mword objsize)
1970 bytes_pinned_from_failed_allocation += objsize;
1974 sgen_collection_is_parallel (void)
1976 switch (current_collection_generation) {
1977 case GENERATION_NURSERY:
1978 return nursery_collection_is_parallel;
1979 case GENERATION_OLD:
1980 return major_collector.is_parallel;
1982 g_error ("Invalid current generation %d", current_collection_generation);
1987 sgen_collection_is_concurrent (void)
1989 switch (current_collection_generation) {
1990 case GENERATION_NURSERY:
1992 case GENERATION_OLD:
1993 return concurrent_collection_in_progress;
1995 g_error ("Invalid current generation %d", current_collection_generation);
2000 sgen_concurrent_collection_in_progress (void)
2002 return concurrent_collection_in_progress;
2009 } FinishRememberedSetScanJobData;
2012 job_finish_remembered_set_scan (WorkerData *worker_data, void *job_data_untyped)
2014 FinishRememberedSetScanJobData *job_data = job_data_untyped;
2016 remset.finish_scan_remsets (job_data->heap_start, job_data->heap_end, sgen_workers_get_job_gray_queue (worker_data));
2017 sgen_free_internal_dynamic (job_data, sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2022 CopyOrMarkObjectFunc copy_or_mark_func;
2023 ScanObjectFunc scan_func;
2027 } ScanFromRegisteredRootsJobData;
2030 job_scan_from_registered_roots (WorkerData *worker_data, void *job_data_untyped)
2032 ScanFromRegisteredRootsJobData *job_data = job_data_untyped;
2033 ScanCopyContext ctx = { job_data->scan_func, job_data->copy_or_mark_func,
2034 sgen_workers_get_job_gray_queue (worker_data) };
2036 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
2037 sgen_free_internal_dynamic (job_data, sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2044 } ScanThreadDataJobData;
2047 job_scan_thread_data (WorkerData *worker_data, void *job_data_untyped)
2049 ScanThreadDataJobData *job_data = job_data_untyped;
2051 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE,
2052 sgen_workers_get_job_gray_queue (worker_data));
2053 sgen_free_internal_dynamic (job_data, sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2058 FinalizeReadyEntry *list;
2059 } ScanFinalizerEntriesJobData;
2062 job_scan_finalizer_entries (WorkerData *worker_data, void *job_data_untyped)
2064 ScanFinalizerEntriesJobData *job_data = job_data_untyped;
2065 ScanCopyContext ctx = { NULL, current_object_ops.copy_or_mark_object, sgen_workers_get_job_gray_queue (worker_data) };
2067 scan_finalizer_entries (job_data->list, ctx);
2068 sgen_free_internal_dynamic (job_data, sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA);
2072 job_scan_major_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2074 g_assert (concurrent_collection_in_progress);
2075 major_collector.scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2079 job_scan_los_mod_union_cardtable (WorkerData *worker_data, void *job_data_untyped)
2081 g_assert (concurrent_collection_in_progress);
2082 sgen_los_scan_card_table (TRUE, sgen_workers_get_job_gray_queue (worker_data));
2086 verify_scan_starts (char *start, char *end)
2090 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2091 char *addr = nursery_section->scan_starts [i];
2092 if (addr > start && addr < end)
2093 SGEN_LOG (1, "NFC-BAD SCAN START [%ld] %p for obj [%p %p]", i, addr, start, end);
2098 verify_nursery (void)
2100 char *start, *end, *cur, *hole_start;
2102 if (!do_verify_nursery)
2105 /*This cleans up unused fragments */
2106 sgen_nursery_allocator_prepare_for_pinning ();
2108 hole_start = start = cur = sgen_get_nursery_start ();
2109 end = sgen_get_nursery_end ();
2114 if (!*(void**)cur) {
2115 cur += sizeof (void*);
2119 if (object_is_forwarded (cur))
2120 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2121 else if (object_is_pinned (cur))
2122 SGEN_LOG (1, "PINNED OBJ %p", cur);
2124 ss = safe_object_get_size ((MonoObject*)cur);
2125 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2126 verify_scan_starts (cur, cur + size);
2127 if (do_dump_nursery_content) {
2128 if (cur > hole_start)
2129 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2130 SGEN_LOG (1, "OBJ [%p %p %d %d %s %d]", cur, cur + size, (int)size, (int)ss, sgen_safe_name ((MonoObject*)cur), (gpointer)LOAD_VTABLE (cur) == sgen_get_array_fill_vtable ());
2138 * Checks that no objects in the nursery are fowarded or pinned. This
2139 * is a precondition to restarting the mutator while doing a
2140 * concurrent collection. Note that we don't clear fragments because
2141 * we depend on that having happened earlier.
2144 check_nursery_is_clean (void)
2146 char *start, *end, *cur;
2148 start = cur = sgen_get_nursery_start ();
2149 end = sgen_get_nursery_end ();
2154 if (!*(void**)cur) {
2155 cur += sizeof (void*);
2159 g_assert (!object_is_forwarded (cur));
2160 g_assert (!object_is_pinned (cur));
2162 ss = safe_object_get_size ((MonoObject*)cur);
2163 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2164 verify_scan_starts (cur, cur + size);
2171 init_gray_queue (void)
2173 if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ()) {
2174 sgen_workers_init_distribute_gray_queue ();
2175 sgen_gray_object_queue_init_with_alloc_prepare (&gray_queue, NULL,
2176 gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
2178 sgen_gray_object_queue_init (&gray_queue, NULL);
2183 pin_stage_object_callback (char *obj, size_t size, void *data)
2185 sgen_pin_stage_ptr (obj);
2186 /* FIXME: do pin stats if enabled */
2190 * Collect objects in the nursery. Returns whether to trigger a major
2194 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2196 gboolean needs_major;
2197 size_t max_garbage_amount;
2199 FinishRememberedSetScanJobData *frssjd;
2200 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2201 ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
2202 ScanThreadDataJobData *stdjd;
2203 mword fragment_total;
2204 ScanCopyContext ctx;
2205 TV_DECLARE (all_atv);
2206 TV_DECLARE (all_btv);
2210 if (disable_minor_collections)
2213 MONO_GC_BEGIN (GENERATION_NURSERY);
2214 binary_protocol_collection_begin (stat_minor_gcs, GENERATION_NURSERY);
2218 #ifndef DISABLE_PERFCOUNTERS
2219 mono_perfcounters->gc_collections0++;
2222 current_collection_generation = GENERATION_NURSERY;
2223 if (sgen_collection_is_parallel ())
2224 current_object_ops = sgen_minor_collector.parallel_ops;
2226 current_object_ops = sgen_minor_collector.serial_ops;
2228 reset_pinned_from_failed_allocation ();
2230 check_scan_starts ();
2232 sgen_nursery_alloc_prepare_for_minor ();
2236 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2237 /* FIXME: optimize later to use the higher address where an object can be present */
2238 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2240 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", stat_minor_gcs, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ()));
2241 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2242 g_assert (nursery_section->size >= max_garbage_amount);
2244 /* world must be stopped already */
2245 TV_GETTIME (all_atv);
2249 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2251 if (xdomain_checks) {
2252 sgen_clear_nursery_fragments ();
2253 sgen_check_for_xdomain_refs ();
2256 nursery_section->next_data = nursery_next;
2258 major_collector.start_nursery_collection ();
2260 sgen_memgov_minor_collection_start ();
2265 gc_stats.minor_gc_count ++;
2267 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2269 sgen_process_fin_stage_entries ();
2270 sgen_process_dislink_stage_entries ();
2272 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2274 /* pin from pinned handles */
2275 sgen_init_pinning ();
2276 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2277 pin_from_roots (sgen_get_nursery_start (), nursery_next, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2278 /* pin cemented objects */
2279 sgen_cement_iterate (pin_stage_object_callback, NULL);
2280 /* identify pinned objects */
2281 sgen_optimize_pin_queue (0);
2282 sgen_pinning_setup_section (nursery_section);
2283 ctx.scan_func = NULL;
2284 ctx.copy_func = NULL;
2285 ctx.queue = WORKERS_DISTRIBUTE_GRAY_QUEUE;
2286 sgen_pin_objects_in_section (nursery_section, ctx);
2287 sgen_pinning_trim_queue_to_section (nursery_section);
2290 time_minor_pinning += TV_ELAPSED (btv, atv);
2291 SGEN_LOG (2, "Finding pinned pointers: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2292 SGEN_LOG (4, "Start scan with %d pinned objects", sgen_get_pinned_count ());
2294 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2296 if (whole_heap_check_before_collection) {
2297 sgen_clear_nursery_fragments ();
2298 sgen_check_whole_heap (finish_up_concurrent_mark);
2300 if (consistency_check_at_minor_collection)
2301 sgen_check_consistency ();
2303 sgen_workers_start_all_workers ();
2304 sgen_workers_start_marking ();
2306 frssjd = sgen_alloc_internal_dynamic (sizeof (FinishRememberedSetScanJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2307 frssjd->heap_start = sgen_get_nursery_start ();
2308 frssjd->heap_end = nursery_next;
2309 sgen_workers_enqueue_job (job_finish_remembered_set_scan, frssjd);
2311 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2313 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2314 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2316 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2318 if (!sgen_collection_is_parallel ()) {
2319 ctx.scan_func = current_object_ops.scan_object;
2320 ctx.copy_func = NULL;
2321 ctx.queue = &gray_queue;
2322 sgen_drain_gray_stack (-1, ctx);
2325 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2326 report_registered_roots ();
2327 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2328 report_finalizer_roots ();
2330 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2332 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2334 /* registered roots, this includes static fields */
2335 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2336 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2337 scrrjd_normal->scan_func = current_object_ops.scan_object;
2338 scrrjd_normal->heap_start = sgen_get_nursery_start ();
2339 scrrjd_normal->heap_end = nursery_next;
2340 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2341 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2343 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2344 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2345 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2346 scrrjd_wbarrier->heap_start = sgen_get_nursery_start ();
2347 scrrjd_wbarrier->heap_end = nursery_next;
2348 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2349 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2352 time_minor_scan_registered_roots += TV_ELAPSED (atv, btv);
2354 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2357 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2358 stdjd->heap_start = sgen_get_nursery_start ();
2359 stdjd->heap_end = nursery_next;
2360 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2363 time_minor_scan_thread_data += TV_ELAPSED (btv, atv);
2366 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2368 g_assert (!sgen_collection_is_parallel () && !sgen_collection_is_concurrent ());
2370 if (sgen_collection_is_parallel () || sgen_collection_is_concurrent ())
2371 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2373 /* Scan the list of objects ready for finalization. If */
2374 sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2375 sfejd_fin_ready->list = fin_ready_list;
2376 sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2378 sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2379 sfejd_critical_fin->list = critical_fin_list;
2380 sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2382 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2384 finish_gray_stack (GENERATION_NURSERY, &gray_queue);
2386 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2387 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2389 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2392 * The (single-threaded) finalization code might have done
2393 * some copying/marking so we can only reset the GC thread's
2394 * worker data here instead of earlier when we joined the
2397 sgen_workers_reset_data ();
2399 if (objects_pinned) {
2400 sgen_optimize_pin_queue (0);
2401 sgen_pinning_setup_section (nursery_section);
2404 /* walk the pin_queue, build up the fragment list of free memory, unmark
2405 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2408 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2409 fragment_total = sgen_build_nursery_fragments (nursery_section,
2410 nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries,
2412 if (!fragment_total)
2415 /* Clear TLABs for all threads */
2416 sgen_clear_tlabs ();
2418 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2420 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2421 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2423 if (consistency_check_at_minor_collection)
2424 sgen_check_major_refs ();
2426 major_collector.finish_nursery_collection ();
2428 TV_GETTIME (all_btv);
2429 gc_stats.minor_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
2432 dump_heap ("minor", stat_minor_gcs - 1, NULL);
2434 /* prepare the pin queue for the next collection */
2435 sgen_finish_pinning ();
2436 if (fin_ready_list || critical_fin_list) {
2437 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2438 mono_gc_finalize_notify ();
2440 sgen_pin_stats_reset ();
2441 /* clear cemented hash */
2442 sgen_cement_clear_below_threshold ();
2444 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2446 remset.finish_minor_collection ();
2448 check_scan_starts ();
2450 binary_protocol_flush_buffers (FALSE);
2452 sgen_memgov_minor_collection_end ();
2454 /*objects are late pinned because of lack of memory, so a major is a good call*/
2455 needs_major = objects_pinned > 0;
2456 current_collection_generation = -1;
2459 MONO_GC_END (GENERATION_NURSERY);
2460 binary_protocol_collection_end (stat_minor_gcs - 1, GENERATION_NURSERY);
2462 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2463 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2469 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2471 ctx->scan_func (obj, ctx->queue);
2475 scan_nursery_objects (ScanCopyContext ctx)
2477 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2478 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2482 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, gboolean finish_up_concurrent_mark, gboolean scan_mod_union)
2487 /* FIXME: only use these values for the precise scan
2488 * note that to_space pointers should be excluded anyway...
2490 char *heap_start = NULL;
2491 char *heap_end = (char*)-1;
2492 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2493 GCRootReport root_report = { 0 };
2494 ScanFromRegisteredRootsJobData *scrrjd_normal, *scrrjd_wbarrier;
2495 ScanThreadDataJobData *stdjd;
2496 ScanFinalizerEntriesJobData *sfejd_fin_ready, *sfejd_critical_fin;
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_cement_iterate (pin_stage_object_callback, NULL);
2562 if (!concurrent_collection_in_progress)
2563 sgen_cement_reset ();
2566 sgen_optimize_pin_queue (0);
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);
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 sgen_pin_objects_in_section (nursery_section, 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: %d in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2666 SGEN_LOG (4, "Start scan with %d 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 (!concurrent_collection_in_progress && major_collector.is_parallel) {
2675 sgen_workers_start_all_workers ();
2676 sgen_workers_start_marking ();
2679 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2680 report_registered_roots ();
2682 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2684 /* registered roots, this includes static fields */
2685 scrrjd_normal = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2686 scrrjd_normal->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2687 scrrjd_normal->scan_func = current_object_ops.scan_object;
2688 scrrjd_normal->heap_start = heap_start;
2689 scrrjd_normal->heap_end = heap_end;
2690 scrrjd_normal->root_type = ROOT_TYPE_NORMAL;
2691 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_normal);
2693 scrrjd_wbarrier = sgen_alloc_internal_dynamic (sizeof (ScanFromRegisteredRootsJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2694 scrrjd_wbarrier->copy_or_mark_func = current_object_ops.copy_or_mark_object;
2695 scrrjd_wbarrier->scan_func = current_object_ops.scan_object;
2696 scrrjd_wbarrier->heap_start = heap_start;
2697 scrrjd_wbarrier->heap_end = heap_end;
2698 scrrjd_wbarrier->root_type = ROOT_TYPE_WBARRIER;
2699 sgen_workers_enqueue_job (job_scan_from_registered_roots, scrrjd_wbarrier);
2702 time_major_scan_registered_roots += TV_ELAPSED (atv, btv);
2705 stdjd = sgen_alloc_internal_dynamic (sizeof (ScanThreadDataJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2706 stdjd->heap_start = heap_start;
2707 stdjd->heap_end = heap_end;
2708 sgen_workers_enqueue_job (job_scan_thread_data, stdjd);
2711 time_major_scan_thread_data += TV_ELAPSED (btv, atv);
2714 time_major_scan_alloc_pinned += TV_ELAPSED (atv, btv);
2716 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2717 report_finalizer_roots ();
2719 /* scan the list of objects ready for finalization */
2720 sfejd_fin_ready = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2721 sfejd_fin_ready->list = fin_ready_list;
2722 sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_fin_ready);
2724 sfejd_critical_fin = sgen_alloc_internal_dynamic (sizeof (ScanFinalizerEntriesJobData), INTERNAL_MEM_WORKER_JOB_DATA, TRUE);
2725 sfejd_critical_fin->list = critical_fin_list;
2726 sgen_workers_enqueue_job (job_scan_finalizer_entries, sfejd_critical_fin);
2728 if (scan_mod_union) {
2729 g_assert (finish_up_concurrent_mark);
2731 /* Mod union card table */
2732 sgen_workers_enqueue_job (job_scan_major_mod_union_cardtable, NULL);
2733 sgen_workers_enqueue_job (job_scan_los_mod_union_cardtable, NULL);
2737 time_major_scan_finalized += TV_ELAPSED (btv, atv);
2738 SGEN_LOG (2, "Root scan: %d usecs", TV_ELAPSED (btv, atv));
2741 time_major_scan_big_objects += TV_ELAPSED (atv, btv);
2743 if (concurrent_collection_in_progress) {
2744 /* prepare the pin queue for the next collection */
2745 sgen_finish_pinning ();
2747 sgen_pin_stats_reset ();
2749 if (do_concurrent_checks)
2750 check_nursery_is_clean ();
2755 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2757 MONO_GC_BEGIN (GENERATION_OLD);
2758 binary_protocol_collection_begin (stat_major_gcs, GENERATION_OLD);
2760 current_collection_generation = GENERATION_OLD;
2761 #ifndef DISABLE_PERFCOUNTERS
2762 mono_perfcounters->gc_collections1++;
2765 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2768 g_assert (major_collector.is_concurrent);
2769 concurrent_collection_in_progress = TRUE;
2771 sgen_cement_concurrent_start ();
2773 current_object_ops = major_collector.major_concurrent_ops;
2775 current_object_ops = major_collector.major_ops;
2778 reset_pinned_from_failed_allocation ();
2780 sgen_memgov_major_collection_start ();
2782 //count_ref_nonref_objs ();
2783 //consistency_check ();
2785 check_scan_starts ();
2788 SGEN_LOG (1, "Start major collection %d", stat_major_gcs);
2790 gc_stats.major_gc_count ++;
2792 if (major_collector.start_major_collection)
2793 major_collector.start_major_collection ();
2795 major_copy_or_mark_from_roots (old_next_pin_slot, FALSE, FALSE);
2799 wait_for_workers_to_finish (void)
2801 while (!sgen_workers_all_done ())
2808 if (concurrent_collection_in_progress || major_collector.is_parallel) {
2809 gray_queue_redirect (&gray_queue);
2810 sgen_workers_join ();
2813 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2815 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2816 main_gc_thread = NULL;
2821 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean scan_mod_union)
2823 LOSObject *bigobj, *prevbo;
2829 if (concurrent_collection_in_progress || major_collector.is_parallel)
2832 if (concurrent_collection_in_progress) {
2833 current_object_ops = major_collector.major_concurrent_ops;
2835 major_copy_or_mark_from_roots (NULL, TRUE, scan_mod_union);
2838 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2840 if (do_concurrent_checks)
2841 check_nursery_is_clean ();
2843 current_object_ops = major_collector.major_ops;
2847 * The workers have stopped so we need to finish gray queue
2848 * work that might result from finalization in the main GC
2849 * thread. Redirection must therefore be turned off.
2851 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2852 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2854 /* all the objects in the heap */
2855 finish_gray_stack (GENERATION_OLD, &gray_queue);
2857 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2860 * The (single-threaded) finalization code might have done
2861 * some copying/marking so we can only reset the GC thread's
2862 * worker data here instead of earlier when we joined the
2865 sgen_workers_reset_data ();
2867 if (objects_pinned) {
2868 g_assert (!concurrent_collection_in_progress);
2870 /*This is slow, but we just OOM'd*/
2871 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2872 sgen_optimize_pin_queue (0);
2873 sgen_find_section_pin_queue_start_end (nursery_section);
2877 reset_heap_boundaries ();
2878 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2880 if (check_mark_bits_after_major_collection)
2881 sgen_check_major_heap_marked ();
2883 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2885 /* sweep the big objects list */
2887 for (bigobj = los_object_list; bigobj;) {
2888 g_assert (!object_is_pinned (bigobj->data));
2889 if (sgen_los_object_is_pinned (bigobj->data)) {
2890 sgen_los_unpin_object (bigobj->data);
2891 sgen_update_heap_boundaries ((mword)bigobj->data, (mword)bigobj->data + sgen_los_object_size (bigobj));
2894 /* not referenced anywhere, so we can free it */
2896 prevbo->next = bigobj->next;
2898 los_object_list = bigobj->next;
2900 bigobj = bigobj->next;
2901 sgen_los_free_object (to_free);
2905 bigobj = bigobj->next;
2909 time_major_free_bigobjs += TV_ELAPSED (atv, btv);
2914 time_major_los_sweep += TV_ELAPSED (btv, atv);
2916 major_collector.sweep ();
2918 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2921 time_major_sweep += TV_ELAPSED (atv, btv);
2923 if (!concurrent_collection_in_progress) {
2924 /* walk the pin_queue, build up the fragment list of free memory, unmark
2925 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2928 if (!sgen_build_nursery_fragments (nursery_section, nursery_section->pin_queue_start, nursery_section->pin_queue_num_entries, NULL))
2931 /* prepare the pin queue for the next collection */
2932 sgen_finish_pinning ();
2934 /* Clear TLABs for all threads */
2935 sgen_clear_tlabs ();
2937 sgen_pin_stats_reset ();
2940 if (concurrent_collection_in_progress)
2941 sgen_cement_concurrent_finish ();
2942 sgen_cement_clear_below_threshold ();
2945 time_major_fragment_creation += TV_ELAPSED (btv, atv);
2948 dump_heap ("major", stat_major_gcs - 1, reason);
2950 if (fin_ready_list || critical_fin_list) {
2951 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2952 mono_gc_finalize_notify ();
2955 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2957 sgen_memgov_major_collection_end ();
2958 current_collection_generation = -1;
2960 major_collector.finish_major_collection ();
2962 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2964 if (concurrent_collection_in_progress)
2965 concurrent_collection_in_progress = FALSE;
2967 check_scan_starts ();
2969 binary_protocol_flush_buffers (FALSE);
2971 //consistency_check ();
2973 MONO_GC_END (GENERATION_OLD);
2974 binary_protocol_collection_end (stat_major_gcs - 1, GENERATION_OLD);
2978 major_do_collection (const char *reason)
2980 TV_DECLARE (all_atv);
2981 TV_DECLARE (all_btv);
2982 size_t old_next_pin_slot;
2984 if (disable_major_collections)
2987 if (major_collector.get_and_reset_num_major_objects_marked) {
2988 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2989 g_assert (!num_marked);
2992 /* world must be stopped already */
2993 TV_GETTIME (all_atv);
2995 major_start_collection (FALSE, &old_next_pin_slot);
2996 major_finish_collection (reason, old_next_pin_slot, FALSE);
2998 TV_GETTIME (all_btv);
2999 gc_stats.major_gc_time_usecs += TV_ELAPSED (all_atv, all_btv);
3001 /* FIXME: also report this to the user, preferably in gc-end. */
3002 if (major_collector.get_and_reset_num_major_objects_marked)
3003 major_collector.get_and_reset_num_major_objects_marked ();
3005 return bytes_pinned_from_failed_allocation > 0;
3009 major_start_concurrent_collection (const char *reason)
3011 long long num_objects_marked;
3013 if (disable_major_collections)
3016 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3017 g_assert (num_objects_marked == 0);
3019 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
3020 binary_protocol_concurrent_start ();
3022 // FIXME: store reason and pass it when finishing
3023 major_start_collection (TRUE, NULL);
3025 gray_queue_redirect (&gray_queue);
3026 sgen_workers_wait_for_jobs ();
3028 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
3029 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
3031 current_collection_generation = -1;
3035 major_update_or_finish_concurrent_collection (gboolean force_finish)
3037 SgenGrayQueue unpin_queue;
3038 memset (&unpin_queue, 0, sizeof (unpin_queue));
3040 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3041 binary_protocol_concurrent_update_finish ();
3043 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3045 if (!force_finish && !sgen_workers_all_done ()) {
3046 major_collector.update_cardtable_mod_union ();
3047 sgen_los_update_cardtable_mod_union ();
3049 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3054 * The major collector can add global remsets which are processed in the finishing
3055 * nursery collection, below. That implies that the workers must have finished
3056 * marking before the nursery collection is allowed to run, otherwise we might miss
3059 wait_for_workers_to_finish ();
3061 major_collector.update_cardtable_mod_union ();
3062 sgen_los_update_cardtable_mod_union ();
3064 collect_nursery (&unpin_queue, TRUE);
3066 if (mod_union_consistency_check)
3067 sgen_check_mod_union_consistency ();
3069 current_collection_generation = GENERATION_OLD;
3070 major_finish_collection ("finishing", -1, TRUE);
3072 if (whole_heap_check_before_collection)
3073 sgen_check_whole_heap (FALSE);
3075 unpin_objects_from_queue (&unpin_queue);
3076 sgen_gray_object_queue_deinit (&unpin_queue);
3078 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3080 current_collection_generation = -1;
3086 * Ensure an allocation request for @size will succeed by freeing enough memory.
3088 * LOCKING: The GC lock MUST be held.
3091 sgen_ensure_free_space (size_t size)
3093 int generation_to_collect = -1;
3094 const char *reason = NULL;
3097 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3098 if (sgen_need_major_collection (size)) {
3099 reason = "LOS overflow";
3100 generation_to_collect = GENERATION_OLD;
3103 if (degraded_mode) {
3104 if (sgen_need_major_collection (size)) {
3105 reason = "Degraded mode overflow";
3106 generation_to_collect = GENERATION_OLD;
3108 } else if (sgen_need_major_collection (size)) {
3109 reason = "Minor allowance";
3110 generation_to_collect = GENERATION_OLD;
3112 generation_to_collect = GENERATION_NURSERY;
3113 reason = "Nursery full";
3117 if (generation_to_collect == -1) {
3118 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3119 generation_to_collect = GENERATION_OLD;
3120 reason = "Finish concurrent collection";
3124 if (generation_to_collect == -1)
3126 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3130 * LOCKING: Assumes the GC lock is held.
3133 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3135 TV_DECLARE (gc_end);
3136 GGTimingInfo infos [2];
3137 int overflow_generation_to_collect = -1;
3138 int oldest_generation_collected = generation_to_collect;
3139 const char *overflow_reason = NULL;
3141 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3143 binary_protocol_collection_force (generation_to_collect);
3145 g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
3147 memset (infos, 0, sizeof (infos));
3148 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3150 infos [0].generation = generation_to_collect;
3151 infos [0].reason = reason;
3152 infos [0].is_overflow = FALSE;
3153 TV_GETTIME (infos [0].total_time);
3154 infos [1].generation = -1;
3156 sgen_stop_world (generation_to_collect);
3158 if (concurrent_collection_in_progress) {
3159 if (major_update_or_finish_concurrent_collection (wait_to_finish && generation_to_collect == GENERATION_OLD)) {
3160 oldest_generation_collected = GENERATION_OLD;
3163 if (generation_to_collect == GENERATION_OLD)
3166 if (generation_to_collect == GENERATION_OLD &&
3167 allow_synchronous_major &&
3168 major_collector.want_synchronous_collection &&
3169 *major_collector.want_synchronous_collection) {
3170 wait_to_finish = TRUE;
3174 //FIXME extract overflow reason
3175 if (generation_to_collect == GENERATION_NURSERY) {
3176 if (collect_nursery (NULL, FALSE)) {
3177 overflow_generation_to_collect = GENERATION_OLD;
3178 overflow_reason = "Minor overflow";
3181 if (major_collector.is_concurrent) {
3182 g_assert (!concurrent_collection_in_progress);
3183 if (!wait_to_finish)
3184 collect_nursery (NULL, FALSE);
3187 if (major_collector.is_concurrent && !wait_to_finish) {
3188 major_start_concurrent_collection (reason);
3189 // FIXME: set infos[0] properly
3192 if (major_do_collection (reason)) {
3193 overflow_generation_to_collect = GENERATION_NURSERY;
3194 overflow_reason = "Excessive pinning";
3199 TV_GETTIME (gc_end);
3200 infos [0].total_time = SGEN_TV_ELAPSED (infos [0].total_time, gc_end);
3203 if (!major_collector.is_concurrent && overflow_generation_to_collect != -1) {
3204 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3205 infos [1].generation = overflow_generation_to_collect;
3206 infos [1].reason = overflow_reason;
3207 infos [1].is_overflow = TRUE;
3208 infos [1].total_time = gc_end;
3210 if (overflow_generation_to_collect == GENERATION_NURSERY)
3211 collect_nursery (NULL, FALSE);
3213 major_do_collection (overflow_reason);
3215 TV_GETTIME (gc_end);
3216 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3218 /* keep events symmetric */
3219 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3221 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3224 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3226 /* this also sets the proper pointers for the next allocation */
3227 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3228 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3229 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%d pinned)", requested_size, sgen_get_pinned_count ());
3230 sgen_dump_pin_queue ();
3235 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3237 sgen_restart_world (oldest_generation_collected, infos);
3239 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3243 * ######################################################################
3244 * ######## Memory allocation from the OS
3245 * ######################################################################
3246 * This section of code deals with getting memory from the OS and
3247 * allocating memory for GC-internal data structures.
3248 * Internal memory can be handled with a freelist for small objects.
3254 G_GNUC_UNUSED static void
3255 report_internal_mem_usage (void)
3257 printf ("Internal memory usage:\n");
3258 sgen_report_internal_mem_usage ();
3259 printf ("Pinned memory usage:\n");
3260 major_collector.report_pinned_memory_usage ();
3264 * ######################################################################
3265 * ######## Finalization support
3266 * ######################################################################
3269 static inline gboolean
3270 sgen_major_is_object_alive (void *object)
3274 /* Oldgen objects can be pinned and forwarded too */
3275 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3279 * FIXME: major_collector.is_object_live() also calculates the
3280 * size. Avoid the double calculation.
3282 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3283 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3284 return sgen_los_object_is_pinned (object);
3286 return major_collector.is_object_live (object);
3290 * If the object has been forwarded it means it's still referenced from a root.
3291 * If it is pinned it's still alive as well.
3292 * A LOS object is only alive if we have pinned it.
3293 * Return TRUE if @obj is ready to be finalized.
3295 static inline gboolean
3296 sgen_is_object_alive (void *object)
3298 if (ptr_in_nursery (object))
3299 return sgen_nursery_is_object_alive (object);
3301 return sgen_major_is_object_alive (object);
3305 * This function returns true if @object is either alive or it belongs to the old gen
3306 * and we're currently doing a minor collection.
3309 sgen_is_object_alive_for_current_gen (char *object)
3311 if (ptr_in_nursery (object))
3312 return sgen_nursery_is_object_alive (object);
3314 if (current_collection_generation == GENERATION_NURSERY)
3317 return sgen_major_is_object_alive (object);
3321 * This function returns true if @object is either alive and belongs to the
3322 * current collection - major collections are full heap, so old gen objects
3323 * are never alive during a minor collection.
3326 sgen_is_object_alive_and_on_current_collection (char *object)
3328 if (ptr_in_nursery (object))
3329 return sgen_nursery_is_object_alive (object);
3331 if (current_collection_generation == GENERATION_NURSERY)
3334 return sgen_major_is_object_alive (object);
3339 sgen_gc_is_object_ready_for_finalization (void *object)
3341 return !sgen_is_object_alive (object);
3345 has_critical_finalizer (MonoObject *obj)
3349 if (!mono_defaults.critical_finalizer_object)
3352 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3354 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3358 is_finalization_aware (MonoObject *obj)
3360 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3361 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3365 sgen_queue_finalization_entry (MonoObject *obj)
3367 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3368 gboolean critical = has_critical_finalizer (obj);
3369 entry->object = obj;
3371 entry->next = critical_fin_list;
3372 critical_fin_list = entry;
3374 entry->next = fin_ready_list;
3375 fin_ready_list = entry;
3378 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3379 fin_callbacks.object_queued_for_finalization (obj);
3381 #ifdef ENABLE_DTRACE
3382 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3383 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3384 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3385 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3386 vt->klass->name_space, vt->klass->name, gen, critical);
3392 sgen_object_is_live (void *obj)
3394 return sgen_is_object_alive_and_on_current_collection (obj);
3397 /* LOCKING: requires that the GC lock is held */
3399 null_ephemerons_for_domain (MonoDomain *domain)
3401 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3404 MonoObject *object = (MonoObject*)current->array;
3406 if (object && !object->vtable) {
3407 EphemeronLinkNode *tmp = current;
3410 prev->next = current->next;
3412 ephemeron_list = current->next;
3414 current = current->next;
3415 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3418 current = current->next;
3423 /* LOCKING: requires that the GC lock is held */
3425 clear_unreachable_ephemerons (ScanCopyContext ctx)
3427 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3428 GrayQueue *queue = ctx.queue;
3429 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3431 Ephemeron *cur, *array_end;
3435 char *object = current->array;
3437 if (!sgen_is_object_alive_for_current_gen (object)) {
3438 EphemeronLinkNode *tmp = current;
3440 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3443 prev->next = current->next;
3445 ephemeron_list = current->next;
3447 current = current->next;
3448 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3453 copy_func ((void**)&object, queue);
3454 current->array = object;
3456 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3458 array = (MonoArray*)object;
3459 cur = mono_array_addr (array, Ephemeron, 0);
3460 array_end = cur + mono_array_length_fast (array);
3461 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3463 for (; cur < array_end; ++cur) {
3464 char *key = (char*)cur->key;
3466 if (!key || key == tombstone)
3469 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3470 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3471 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3473 if (!sgen_is_object_alive_for_current_gen (key)) {
3474 cur->key = tombstone;
3480 current = current->next;
3485 LOCKING: requires that the GC lock is held
3487 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3490 mark_ephemerons_in_range (ScanCopyContext ctx)
3492 CopyOrMarkObjectFunc copy_func = ctx.copy_func;
3493 GrayQueue *queue = ctx.queue;
3494 int nothing_marked = 1;
3495 EphemeronLinkNode *current = ephemeron_list;
3497 Ephemeron *cur, *array_end;
3500 for (current = ephemeron_list; current; current = current->next) {
3501 char *object = current->array;
3502 SGEN_LOG (5, "Ephemeron array at %p", object);
3504 /*It has to be alive*/
3505 if (!sgen_is_object_alive_for_current_gen (object)) {
3506 SGEN_LOG (5, "\tnot reachable");
3510 copy_func ((void**)&object, queue);
3512 array = (MonoArray*)object;
3513 cur = mono_array_addr (array, Ephemeron, 0);
3514 array_end = cur + mono_array_length_fast (array);
3515 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3517 for (; cur < array_end; ++cur) {
3518 char *key = cur->key;
3520 if (!key || key == tombstone)
3523 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3524 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3525 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3527 if (sgen_is_object_alive_for_current_gen (key)) {
3528 char *value = cur->value;
3530 copy_func ((void**)&cur->key, queue);
3532 if (!sgen_is_object_alive_for_current_gen (value))
3534 copy_func ((void**)&cur->value, queue);
3540 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3541 return nothing_marked;
3545 mono_gc_invoke_finalizers (void)
3547 FinalizeReadyEntry *entry = NULL;
3548 gboolean entry_is_critical = FALSE;
3551 /* FIXME: batch to reduce lock contention */
3552 while (fin_ready_list || critical_fin_list) {
3556 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3558 /* We have finalized entry in the last
3559 interation, now we need to remove it from
3562 *list = entry->next;
3564 FinalizeReadyEntry *e = *list;
3565 while (e->next != entry)
3567 e->next = entry->next;
3569 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3573 /* Now look for the first non-null entry. */
3574 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3577 entry_is_critical = FALSE;
3579 entry_is_critical = TRUE;
3580 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3585 g_assert (entry->object);
3586 num_ready_finalizers--;
3587 obj = entry->object;
3588 entry->object = NULL;
3589 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3597 g_assert (entry->object == NULL);
3599 /* the object is on the stack so it is pinned */
3600 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3601 mono_gc_run_finalize (obj, NULL);
3608 mono_gc_pending_finalizers (void)
3610 return fin_ready_list || critical_fin_list;
3614 * ######################################################################
3615 * ######## registered roots support
3616 * ######################################################################
3620 * We do not coalesce roots.
3623 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3625 RootRecord new_root;
3628 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3629 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3630 /* we allow changing the size and the descriptor (for thread statics etc) */
3632 size_t old_size = root->end_root - start;
3633 root->end_root = start + size;
3634 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3635 ((root->root_desc == 0) && (descr == NULL)));
3636 root->root_desc = (mword)descr;
3638 roots_size -= old_size;
3644 new_root.end_root = start + size;
3645 new_root.root_desc = (mword)descr;
3647 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3650 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);
3657 mono_gc_register_root (char *start, size_t size, void *descr)
3659 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3663 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3665 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3669 mono_gc_deregister_root (char* addr)
3675 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3676 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3677 roots_size -= (root.end_root - addr);
3683 * ######################################################################
3684 * ######## Thread handling (stop/start code)
3685 * ######################################################################
3688 unsigned int sgen_global_stop_count = 0;
3691 sgen_get_current_collection_generation (void)
3693 return current_collection_generation;
3697 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3699 gc_callbacks = *callbacks;
3703 mono_gc_get_gc_callbacks ()
3705 return &gc_callbacks;
3708 /* Variables holding start/end nursery so it won't have to be passed at every call */
3709 static void *scan_area_arg_start, *scan_area_arg_end;
3712 mono_gc_conservatively_scan_area (void *start, void *end)
3714 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3718 mono_gc_scan_object (void *obj)
3720 UserCopyOrMarkData *data = mono_native_tls_get_value (user_copy_or_mark_key);
3721 current_object_ops.copy_or_mark_object (&obj, data->queue);
3726 * Mark from thread stacks and registers.
3729 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, GrayQueue *queue)
3731 SgenThreadInfo *info;
3733 scan_area_arg_start = start_nursery;
3734 scan_area_arg_end = end_nursery;
3736 FOREACH_THREAD (info) {
3738 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);
3741 if (info->gc_disabled) {
3742 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);
3745 if (mono_thread_info_run_state (info) != STATE_RUNNING) {
3746 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));
3749 SGEN_LOG (3, "Scanning thread %p, range: %p-%p, size: %td, pinned=%d", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, sgen_get_pinned_count ());
3750 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3751 UserCopyOrMarkData data = { NULL, queue };
3752 set_user_copy_or_mark_data (&data);
3753 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise);
3754 set_user_copy_or_mark_data (NULL);
3755 } else if (!precise) {
3756 if (!conservative_stack_mark) {
3757 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3758 conservative_stack_mark = TRUE;
3760 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3765 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3766 start_nursery, end_nursery, PIN_TYPE_STACK);
3768 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3769 start_nursery, end_nursery, PIN_TYPE_STACK);
3772 } END_FOREACH_THREAD
3776 ptr_on_stack (void *ptr)
3778 gpointer stack_start = &stack_start;
3779 SgenThreadInfo *info = mono_thread_info_current ();
3781 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3787 sgen_thread_register (SgenThreadInfo* info, void *addr)
3790 guint8 *staddr = NULL;
3792 #ifndef HAVE_KW_THREAD
3793 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3795 g_assert (!mono_native_tls_get_value (thread_info_key));
3796 mono_native_tls_set_value (thread_info_key, info);
3798 sgen_thread_info = info;
3801 #ifdef SGEN_POSIX_STW
3802 info->stop_count = -1;
3806 info->stack_start = NULL;
3807 info->stopped_ip = NULL;
3808 info->stopped_domain = NULL;
3810 memset (&info->ctx, 0, sizeof (MonoContext));
3812 memset (&info->regs, 0, sizeof (info->regs));
3815 sgen_init_tlab_info (info);
3817 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3819 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3821 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3824 info->stack_start_limit = staddr;
3825 info->stack_end = staddr + stsize;
3827 gsize stack_bottom = (gsize)addr;
3828 stack_bottom += 4095;
3829 stack_bottom &= ~4095;
3830 info->stack_end = (char*)stack_bottom;
3833 #ifdef HAVE_KW_THREAD
3834 stack_end = info->stack_end;
3837 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3839 if (gc_callbacks.thread_attach_func)
3840 info->runtime_data = gc_callbacks.thread_attach_func ();
3845 sgen_thread_detach (SgenThreadInfo *p)
3847 /* If a delegate is passed to native code and invoked on a thread we dont
3848 * know about, the jit will register it with mono_jit_thread_attach, but
3849 * we have no way of knowing when that thread goes away. SGen has a TSD
3850 * so we assume that if the domain is still registered, we can detach
3853 if (mono_domain_get ())
3854 mono_thread_detach_internal (mono_thread_internal_current ());
3858 sgen_thread_unregister (SgenThreadInfo *p)
3860 MonoNativeThreadId tid;
3862 tid = mono_thread_info_get_tid (p);
3863 binary_protocol_thread_unregister ((gpointer)tid);
3864 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3866 mono_threads_add_joinable_thread ((gpointer)tid);
3868 if (gc_callbacks.thread_detach_func) {
3869 gc_callbacks.thread_detach_func (p->runtime_data);
3870 p->runtime_data = NULL;
3876 sgen_thread_attach (SgenThreadInfo *info)
3879 /*this is odd, can we get attached before the gc is inited?*/
3883 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3884 info->runtime_data = gc_callbacks.thread_attach_func ();
3887 mono_gc_register_thread (void *baseptr)
3889 return mono_thread_info_attach (baseptr) != NULL;
3893 * mono_gc_set_stack_end:
3895 * Set the end of the current threads stack to STACK_END. The stack space between
3896 * STACK_END and the real end of the threads stack will not be scanned during collections.
3899 mono_gc_set_stack_end (void *stack_end)
3901 SgenThreadInfo *info;
3904 info = mono_thread_info_current ();
3906 g_assert (stack_end < info->stack_end);
3907 info->stack_end = stack_end;
3912 #if USE_PTHREAD_INTERCEPT
3916 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3918 return pthread_create (new_thread, attr, start_routine, arg);
3922 mono_gc_pthread_join (pthread_t thread, void **retval)
3924 return pthread_join (thread, retval);
3928 mono_gc_pthread_detach (pthread_t thread)
3930 return pthread_detach (thread);
3934 mono_gc_pthread_exit (void *retval)
3936 mono_thread_info_detach ();
3937 pthread_exit (retval);
3940 #endif /* USE_PTHREAD_INTERCEPT */
3943 * ######################################################################
3944 * ######## Write barriers
3945 * ######################################################################
3949 * Note: the write barriers first do the needed GC work and then do the actual store:
3950 * this way the value is visible to the conservative GC scan after the write barrier
3951 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
3952 * the conservative scan, otherwise by the remembered set scan.
3955 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
3957 HEAVY_STAT (++stat_wbarrier_set_field);
3958 if (ptr_in_nursery (field_ptr)) {
3959 *(void**)field_ptr = value;
3962 SGEN_LOG (8, "Adding remset at %p", field_ptr);
3964 binary_protocol_wbarrier (field_ptr, value, value->vtable);
3966 remset.wbarrier_set_field (obj, field_ptr, value);
3970 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
3972 HEAVY_STAT (++stat_wbarrier_set_arrayref);
3973 if (ptr_in_nursery (slot_ptr)) {
3974 *(void**)slot_ptr = value;
3977 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
3979 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
3981 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
3985 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
3987 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
3988 /*This check can be done without taking a lock since dest_ptr array is pinned*/
3989 if (ptr_in_nursery (dest_ptr) || count <= 0) {
3990 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
3994 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
3995 if (binary_protocol_is_heavy_enabled ()) {
3997 for (i = 0; i < count; ++i) {
3998 gpointer dest = (gpointer*)dest_ptr + i;
3999 gpointer obj = *((gpointer*)src_ptr + i);
4001 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
4006 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
4009 static char *found_obj;
4012 find_object_for_ptr_callback (char *obj, size_t size, void *user_data)
4014 char *ptr = user_data;
4016 if (ptr >= obj && ptr < obj + size) {
4017 g_assert (!found_obj);
4022 /* for use in the debugger */
4023 char* find_object_for_ptr (char *ptr);
4025 find_object_for_ptr (char *ptr)
4027 if (ptr >= nursery_section->data && ptr < nursery_section->end_data) {
4029 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
4030 find_object_for_ptr_callback, ptr, TRUE);
4036 sgen_los_iterate_objects (find_object_for_ptr_callback, ptr);
4041 * Very inefficient, but this is debugging code, supposed to
4042 * be called from gdb, so we don't care.
4045 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, find_object_for_ptr_callback, ptr);
4050 mono_gc_wbarrier_generic_nostore (gpointer ptr)
4054 HEAVY_STAT (++stat_wbarrier_generic_store);
4056 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
4057 /* FIXME: ptr_in_heap must be called with the GC lock held */
4058 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
4059 char *start = find_object_for_ptr (ptr);
4060 MonoObject *value = *(MonoObject**)ptr;
4064 MonoObject *obj = (MonoObject*)start;
4065 if (obj->vtable->domain != value->vtable->domain)
4066 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4072 obj = *(gpointer*)ptr;
4074 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4076 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4077 SGEN_LOG (8, "Skipping remset at %p", ptr);
4082 * We need to record old->old pointer locations for the
4083 * concurrent collector.
4085 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4086 SGEN_LOG (8, "Skipping remset at %p", ptr);
4090 SGEN_LOG (8, "Adding remset at %p", ptr);
4092 remset.wbarrier_generic_nostore (ptr);
4096 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4098 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4099 *(void**)ptr = value;
4100 if (ptr_in_nursery (value))
4101 mono_gc_wbarrier_generic_nostore (ptr);
4102 sgen_dummy_use (value);
4105 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4106 * as an atomic operation with release semantics.
4109 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4111 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4113 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4115 InterlockedWritePointer (ptr, value);
4117 if (ptr_in_nursery (value))
4118 mono_gc_wbarrier_generic_nostore (ptr);
4120 sgen_dummy_use (value);
4123 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4125 mword *dest = _dest;
4130 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4135 size -= SIZEOF_VOID_P;
4140 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4142 #define HANDLE_PTR(ptr,obj) do { \
4143 gpointer o = *(gpointer*)(ptr); \
4145 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4146 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4151 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4153 #define SCAN_OBJECT_NOVTABLE
4154 #include "sgen-scan-object.h"
4159 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4161 HEAVY_STAT (++stat_wbarrier_value_copy);
4162 g_assert (klass->valuetype);
4164 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4166 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4167 size_t element_size = mono_class_value_size (klass, NULL);
4168 size_t size = count * element_size;
4169 mono_gc_memmove_atomic (dest, src, size);
4173 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4174 if (binary_protocol_is_heavy_enabled ()) {
4175 size_t element_size = mono_class_value_size (klass, NULL);
4177 for (i = 0; i < count; ++i) {
4178 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4179 (char*)src + i * element_size - sizeof (MonoObject),
4180 (mword) klass->gc_descr);
4185 remset.wbarrier_value_copy (dest, src, count, klass);
4189 * mono_gc_wbarrier_object_copy:
4191 * Write barrier to call when obj is the result of a clone or copy of an object.
4194 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4198 HEAVY_STAT (++stat_wbarrier_object_copy);
4200 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4201 size = mono_object_class (obj)->instance_size;
4202 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4203 size - sizeof (MonoObject));
4207 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4208 if (binary_protocol_is_heavy_enabled ())
4209 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4212 remset.wbarrier_object_copy (obj, src);
4217 * ######################################################################
4218 * ######## Other mono public interface functions.
4219 * ######################################################################
4222 #define REFS_SIZE 128
4225 MonoGCReferences callback;
4229 MonoObject *refs [REFS_SIZE];
4230 uintptr_t offsets [REFS_SIZE];
4234 #define HANDLE_PTR(ptr,obj) do { \
4236 if (hwi->count == REFS_SIZE) { \
4237 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4241 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4242 hwi->refs [hwi->count++] = *(ptr); \
4247 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4249 #include "sgen-scan-object.h"
4253 walk_references (char *start, size_t size, void *data)
4255 HeapWalkInfo *hwi = data;
4258 collect_references (hwi, start, size);
4259 if (hwi->count || !hwi->called)
4260 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4264 * mono_gc_walk_heap:
4265 * @flags: flags for future use
4266 * @callback: a function pointer called for each object in the heap
4267 * @data: a user data pointer that is passed to callback
4269 * This function can be used to iterate over all the live objects in the heap:
4270 * for each object, @callback is invoked, providing info about the object's
4271 * location in memory, its class, its size and the objects it references.
4272 * For each referenced object it's offset from the object address is
4273 * reported in the offsets array.
4274 * The object references may be buffered, so the callback may be invoked
4275 * multiple times for the same object: in all but the first call, the size
4276 * argument will be zero.
4277 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4278 * profiler event handler.
4280 * Returns: a non-zero value if the GC doesn't support heap walking
4283 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4288 hwi.callback = callback;
4291 sgen_clear_nursery_fragments ();
4292 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4294 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4295 sgen_los_iterate_objects (walk_references, &hwi);
4301 mono_gc_collect (int generation)
4306 sgen_perform_collection (0, generation, "user request", TRUE);
4311 mono_gc_max_generation (void)
4317 mono_gc_collection_count (int generation)
4319 if (generation == 0)
4320 return stat_minor_gcs;
4321 return stat_major_gcs;
4325 mono_gc_get_used_size (void)
4329 tot = los_memory_usage;
4330 tot += nursery_section->next_data - nursery_section->data;
4331 tot += major_collector.get_used_size ();
4332 /* FIXME: account for pinned objects */
4338 mono_gc_get_los_limit (void)
4340 return MAX_SMALL_OBJ_SIZE;
4344 mono_gc_user_markers_supported (void)
4350 mono_object_is_alive (MonoObject* o)
4356 mono_gc_get_generation (MonoObject *obj)
4358 if (ptr_in_nursery (obj))
4364 mono_gc_enable_events (void)
4369 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4371 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4375 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4377 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4381 mono_gc_weak_link_get (void **link_addr)
4383 void * volatile *link_addr_volatile;
4387 link_addr_volatile = link_addr;
4388 ptr = (void*)*link_addr_volatile;
4390 * At this point we have a hidden pointer. If the GC runs
4391 * here, it will not recognize the hidden pointer as a
4392 * reference, and if the object behind it is not referenced
4393 * elsewhere, it will be freed. Once the world is restarted
4394 * we reveal the pointer, giving us a pointer to a freed
4395 * object. To make sure we don't return it, we load the
4396 * hidden pointer again. If it's still the same, we can be
4397 * sure the object reference is valid.
4400 obj = (MonoObject*) REVEAL_POINTER (ptr);
4404 mono_memory_barrier ();
4407 * During the second bridge processing step the world is
4408 * running again. That step processes all weak links once
4409 * more to null those that refer to dead objects. Before that
4410 * is completed, those links must not be followed, so we
4411 * conservatively wait for bridge processing when any weak
4412 * link is dereferenced.
4414 if (G_UNLIKELY (bridge_processing_in_progress))
4415 mono_gc_wait_for_bridge_processing ();
4417 if ((void*)*link_addr_volatile != ptr)
4424 mono_gc_ephemeron_array_add (MonoObject *obj)
4426 EphemeronLinkNode *node;
4430 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4435 node->array = (char*)obj;
4436 node->next = ephemeron_list;
4437 ephemeron_list = node;
4439 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4446 mono_gc_set_allow_synchronous_major (gboolean flag)
4448 if (!major_collector.is_concurrent)
4451 allow_synchronous_major = flag;
4456 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4460 result = func (data);
4461 UNLOCK_INTERRUPTION;
4466 mono_gc_is_gc_thread (void)
4470 result = mono_thread_info_current () != NULL;
4476 is_critical_method (MonoMethod *method)
4478 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4482 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4486 va_start (ap, description_format);
4488 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4489 vfprintf (stderr, description_format, ap);
4491 fprintf (stderr, " - %s", fallback);
4492 fprintf (stderr, "\n");
4498 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4501 double val = strtod (opt, &endptr);
4502 if (endptr == opt) {
4503 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4506 else if (val < min || val > max) {
4507 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4515 mono_gc_base_init (void)
4517 MonoThreadInfoCallbacks cb;
4520 char *major_collector_opt = NULL;
4521 char *minor_collector_opt = NULL;
4522 size_t max_heap = 0;
4523 size_t soft_limit = 0;
4527 gboolean debug_print_allowance = FALSE;
4528 double allowance_ratio = 0, save_target = 0;
4529 gboolean have_split_nursery = FALSE;
4530 gboolean cement_enabled = TRUE;
4533 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4536 /* already inited */
4539 /* being inited by another thread */
4543 /* we will init it */
4546 g_assert_not_reached ();
4548 } while (result != 0);
4550 SGEN_TV_GETTIME (sgen_init_timestamp);
4552 LOCK_INIT (gc_mutex);
4554 pagesize = mono_pagesize ();
4555 gc_debug_file = stderr;
4557 cb.thread_register = sgen_thread_register;
4558 cb.thread_detach = sgen_thread_detach;
4559 cb.thread_unregister = sgen_thread_unregister;
4560 cb.thread_attach = sgen_thread_attach;
4561 cb.mono_method_is_critical = (gpointer)is_critical_method;
4563 cb.thread_exit = mono_gc_pthread_exit;
4564 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4567 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4569 LOCK_INIT (sgen_interruption_mutex);
4570 LOCK_INIT (pin_queue_mutex);
4572 init_user_copy_or_mark_key ();
4574 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4575 opts = g_strsplit (env, ",", -1);
4576 for (ptr = opts; *ptr; ++ptr) {
4578 if (g_str_has_prefix (opt, "major=")) {
4579 opt = strchr (opt, '=') + 1;
4580 major_collector_opt = g_strdup (opt);
4581 } else if (g_str_has_prefix (opt, "minor=")) {
4582 opt = strchr (opt, '=') + 1;
4583 minor_collector_opt = g_strdup (opt);
4591 sgen_init_internal_allocator ();
4592 sgen_init_nursery_allocator ();
4593 sgen_init_fin_weak_hash ();
4595 sgen_init_hash_table ();
4597 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4598 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4599 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4600 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4602 #ifndef HAVE_KW_THREAD
4603 mono_native_tls_alloc (&thread_info_key, NULL);
4604 #if defined(__APPLE__) || defined (HOST_WIN32)
4606 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4607 * where the two are the same.
4609 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4613 int tls_offset = -1;
4614 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4615 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4620 * This needs to happen before any internal allocations because
4621 * it inits the small id which is required for hazard pointer
4626 mono_thread_info_attach (&dummy);
4628 if (!minor_collector_opt) {
4629 sgen_simple_nursery_init (&sgen_minor_collector);
4631 if (!strcmp (minor_collector_opt, "simple")) {
4633 sgen_simple_nursery_init (&sgen_minor_collector);
4634 } else if (!strcmp (minor_collector_opt, "split")) {
4635 sgen_split_nursery_init (&sgen_minor_collector);
4636 have_split_nursery = TRUE;
4638 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4639 goto use_simple_nursery;
4643 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4644 use_marksweep_major:
4645 sgen_marksweep_init (&major_collector);
4646 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed")) {
4647 sgen_marksweep_fixed_init (&major_collector);
4648 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-par")) {
4649 sgen_marksweep_par_init (&major_collector);
4650 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-fixed-par")) {
4651 sgen_marksweep_fixed_par_init (&major_collector);
4652 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4653 sgen_marksweep_conc_init (&major_collector);
4655 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4656 goto use_marksweep_major;
4659 if (have_split_nursery && major_collector.is_parallel) {
4660 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Disabling split minor collector.", "`minor=split` is not supported with the parallel collector yet.");
4661 have_split_nursery = FALSE;
4664 num_workers = mono_cpu_count ();
4665 g_assert (num_workers > 0);
4666 if (num_workers > 16)
4669 ///* Keep this the default for now */
4670 /* Precise marking is broken on all supported targets. Disable until fixed. */
4671 conservative_stack_mark = TRUE;
4673 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4676 gboolean usage_printed = FALSE;
4678 for (ptr = opts; *ptr; ++ptr) {
4680 if (!strcmp (opt, ""))
4682 if (g_str_has_prefix (opt, "major="))
4684 if (g_str_has_prefix (opt, "minor="))
4686 if (g_str_has_prefix (opt, "max-heap-size=")) {
4687 size_t max_heap_candidate = 0;
4688 opt = strchr (opt, '=') + 1;
4689 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4690 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4691 if (max_heap != max_heap_candidate)
4692 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4694 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4698 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4699 opt = strchr (opt, '=') + 1;
4700 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4701 if (soft_limit <= 0) {
4702 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4706 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4710 if (g_str_has_prefix (opt, "workers=")) {
4713 if (!major_collector.is_parallel) {
4714 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "The `workers` option can only be used for parallel collectors.");
4717 opt = strchr (opt, '=') + 1;
4718 val = strtol (opt, &endptr, 10);
4719 if (!*opt || *endptr) {
4720 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Cannot parse the `workers` option value.");
4723 if (val <= 0 || val > 16) {
4724 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "The number of `workers` must be in the range 1 to 16.");
4727 num_workers = (int)val;
4730 if (g_str_has_prefix (opt, "stack-mark=")) {
4731 opt = strchr (opt, '=') + 1;
4732 if (!strcmp (opt, "precise")) {
4733 conservative_stack_mark = FALSE;
4734 } else if (!strcmp (opt, "conservative")) {
4735 conservative_stack_mark = TRUE;
4737 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4738 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4742 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4743 opt = strchr (opt, '=') + 1;
4744 sgen_set_bridge_implementation (opt);
4747 if (g_str_has_prefix (opt, "toggleref-test")) {
4748 sgen_register_test_toggleref_callback ();
4753 if (g_str_has_prefix (opt, "nursery-size=")) {
4755 opt = strchr (opt, '=') + 1;
4756 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4757 #ifdef SGEN_ALIGN_NURSERY
4758 if ((val & (val - 1))) {
4759 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4763 if (val < SGEN_MAX_NURSERY_WASTE) {
4764 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4765 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4769 sgen_nursery_size = val;
4770 sgen_nursery_bits = 0;
4771 while (1 << (++ sgen_nursery_bits) != sgen_nursery_size)
4774 sgen_nursery_size = val;
4777 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4783 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4785 opt = strchr (opt, '=') + 1;
4786 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4787 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4792 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4794 opt = strchr (opt, '=') + 1;
4795 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4796 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4797 allowance_ratio = val;
4801 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4802 if (!major_collector.is_concurrent) {
4803 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4807 opt = strchr (opt, '=') + 1;
4809 if (!strcmp (opt, "yes")) {
4810 allow_synchronous_major = TRUE;
4811 } else if (!strcmp (opt, "no")) {
4812 allow_synchronous_major = FALSE;
4814 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4819 if (!strcmp (opt, "cementing")) {
4820 if (major_collector.is_parallel) {
4821 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported for the parallel major collector.");
4824 cement_enabled = TRUE;
4827 if (!strcmp (opt, "no-cementing")) {
4828 cement_enabled = FALSE;
4832 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4835 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4838 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4843 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4844 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4845 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4846 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4847 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par', 'marksweep-fixed' or 'marksweep-fixed-par')\n");
4848 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4849 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4850 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4851 fprintf (stderr, " [no-]cementing\n");
4852 if (major_collector.is_concurrent)
4853 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4854 if (major_collector.print_gc_param_usage)
4855 major_collector.print_gc_param_usage ();
4856 if (sgen_minor_collector.print_gc_param_usage)
4857 sgen_minor_collector.print_gc_param_usage ();
4858 fprintf (stderr, " Experimental options:\n");
4859 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4860 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);
4861 fprintf (stderr, "\n");
4863 usage_printed = TRUE;
4868 if (major_collector.is_parallel) {
4869 cement_enabled = FALSE;
4870 sgen_workers_init (num_workers);
4871 } else if (major_collector.is_concurrent) {
4872 sgen_workers_init (1);
4875 if (major_collector_opt)
4876 g_free (major_collector_opt);
4878 if (minor_collector_opt)
4879 g_free (minor_collector_opt);
4883 sgen_cement_init (cement_enabled);
4885 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4886 gboolean usage_printed = FALSE;
4888 opts = g_strsplit (env, ",", -1);
4889 for (ptr = opts; ptr && *ptr; ptr ++) {
4891 if (!strcmp (opt, ""))
4893 if (opt [0] >= '0' && opt [0] <= '9') {
4894 gc_debug_level = atoi (opt);
4900 char *rf = g_strdup_printf ("%s.%d", opt, GetCurrentProcessId ());
4902 char *rf = g_strdup_printf ("%s.%d", opt, getpid ());
4904 gc_debug_file = fopen (rf, "wb");
4906 gc_debug_file = stderr;
4909 } else if (!strcmp (opt, "print-allowance")) {
4910 debug_print_allowance = TRUE;
4911 } else if (!strcmp (opt, "print-pinning")) {
4912 do_pin_stats = TRUE;
4913 } else if (!strcmp (opt, "verify-before-allocs")) {
4914 verify_before_allocs = 1;
4915 has_per_allocation_action = TRUE;
4916 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4917 char *arg = strchr (opt, '=') + 1;
4918 verify_before_allocs = atoi (arg);
4919 has_per_allocation_action = TRUE;
4920 } else if (!strcmp (opt, "collect-before-allocs")) {
4921 collect_before_allocs = 1;
4922 has_per_allocation_action = TRUE;
4923 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4924 char *arg = strchr (opt, '=') + 1;
4925 has_per_allocation_action = TRUE;
4926 collect_before_allocs = atoi (arg);
4927 } else if (!strcmp (opt, "verify-before-collections")) {
4928 whole_heap_check_before_collection = TRUE;
4929 } else if (!strcmp (opt, "check-at-minor-collections")) {
4930 consistency_check_at_minor_collection = TRUE;
4931 nursery_clear_policy = CLEAR_AT_GC;
4932 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4933 if (!major_collector.is_concurrent) {
4934 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4937 mod_union_consistency_check = TRUE;
4938 } else if (!strcmp (opt, "check-mark-bits")) {
4939 check_mark_bits_after_major_collection = TRUE;
4940 } else if (!strcmp (opt, "check-nursery-pinned")) {
4941 check_nursery_objects_pinned = TRUE;
4942 } else if (!strcmp (opt, "xdomain-checks")) {
4943 xdomain_checks = TRUE;
4944 } else if (!strcmp (opt, "clear-at-gc")) {
4945 nursery_clear_policy = CLEAR_AT_GC;
4946 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4947 nursery_clear_policy = CLEAR_AT_GC;
4948 } else if (!strcmp (opt, "check-scan-starts")) {
4949 do_scan_starts_check = TRUE;
4950 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4951 do_verify_nursery = TRUE;
4952 } else if (!strcmp (opt, "check-concurrent")) {
4953 if (!major_collector.is_concurrent) {
4954 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4957 do_concurrent_checks = TRUE;
4958 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4959 do_dump_nursery_content = TRUE;
4960 } else if (!strcmp (opt, "no-managed-allocator")) {
4961 sgen_set_use_managed_allocator (FALSE);
4962 } else if (!strcmp (opt, "disable-minor")) {
4963 disable_minor_collections = TRUE;
4964 } else if (!strcmp (opt, "disable-major")) {
4965 disable_major_collections = TRUE;
4966 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4967 char *filename = strchr (opt, '=') + 1;
4968 nursery_clear_policy = CLEAR_AT_GC;
4969 heap_dump_file = fopen (filename, "w");
4970 if (heap_dump_file) {
4971 fprintf (heap_dump_file, "<sgen-dump>\n");
4972 do_pin_stats = TRUE;
4974 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4975 char *filename = strchr (opt, '=') + 1;
4976 binary_protocol_init (filename);
4977 } else if (!sgen_bridge_handle_gc_debug (opt)) {
4978 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4983 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);
4984 fprintf (stderr, "Valid <option>s are:\n");
4985 fprintf (stderr, " collect-before-allocs[=<n>]\n");
4986 fprintf (stderr, " verify-before-allocs[=<n>]\n");
4987 fprintf (stderr, " check-at-minor-collections\n");
4988 fprintf (stderr, " check-mark-bits\n");
4989 fprintf (stderr, " check-nursery-pinned\n");
4990 fprintf (stderr, " verify-before-collections\n");
4991 fprintf (stderr, " verify-nursery-at-minor-gc\n");
4992 fprintf (stderr, " dump-nursery-at-minor-gc\n");
4993 fprintf (stderr, " disable-minor\n");
4994 fprintf (stderr, " disable-major\n");
4995 fprintf (stderr, " xdomain-checks\n");
4996 fprintf (stderr, " check-concurrent\n");
4997 fprintf (stderr, " clear-at-gc\n");
4998 fprintf (stderr, " clear-nursery-at-gc\n");
4999 fprintf (stderr, " check-scan-starts\n");
5000 fprintf (stderr, " no-managed-allocator\n");
5001 fprintf (stderr, " print-allowance\n");
5002 fprintf (stderr, " print-pinning\n");
5003 fprintf (stderr, " heap-dump=<filename>\n");
5004 fprintf (stderr, " binary-protocol=<filename>\n");
5005 sgen_bridge_print_gc_debug_usage ();
5006 fprintf (stderr, "\n");
5008 usage_printed = TRUE;
5014 if (major_collector.is_parallel) {
5015 if (heap_dump_file) {
5016 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "Cannot do `heap-dump` with the parallel collector.");
5017 fclose (heap_dump_file);
5018 heap_dump_file = NULL;
5021 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Disabling.", "`print-pinning` is not supported with the parallel collector.");
5022 do_pin_stats = FALSE;
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_icon (mb, (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_icon (mb, (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;
5397 #endif /* HAVE_SGEN_GC */