2 * sgen-gc.c: Simple generational GC.
5 * Paolo Molaro (lupus@ximian.com)
6 * Rodrigo Kumpera (kumpera@gmail.com)
8 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
9 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
11 * Thread start/stop adapted from Boehm's GC:
12 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
13 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
14 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
15 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
16 * Copyright 2001-2003 Ximian, Inc
17 * Copyright 2003-2010 Novell, Inc.
18 * Copyright 2011 Xamarin, Inc.
19 * Copyright (C) 2012 Xamarin Inc
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Library General Public
23 * License 2.0 as published by the Free Software Foundation;
25 * This library is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
28 * Library General Public License for more details.
30 * You should have received a copy of the GNU Library General Public
31 * License 2.0 along with this library; if not, write to the Free
32 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
34 * Important: allocation provides always zeroed memory, having to do
35 * a memset after allocation is deadly for performance.
36 * Memory usage at startup is currently as follows:
38 * 64 KB internal space
40 * We should provide a small memory config with half the sizes
42 * We currently try to make as few mono assumptions as possible:
43 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
45 * 2) gc descriptor is the second word in the vtable (first word in the class)
46 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
47 * 4) there is a function to get an object's size and the number of
48 * elements in an array.
49 * 5) we know the special way bounds are allocated for complex arrays
50 * 6) we know about proxies and how to treat them when domains are unloaded
52 * Always try to keep stack usage to a minimum: no recursive behaviour
53 * and no large stack allocs.
55 * General description.
56 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
57 * When the nursery is full we start a nursery collection: this is performed with a
59 * When the old generation is full we start a copying GC of the old generation as well:
60 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
61 * in the future. Maybe we'll even do both during the same collection like IMMIX.
63 * The things that complicate this description are:
64 * *) pinned objects: we can't move them so we need to keep track of them
65 * *) no precise info of the thread stacks and registers: we need to be able to
66 * quickly find the objects that may be referenced conservatively and pin them
67 * (this makes the first issues more important)
68 * *) large objects are too expensive to be dealt with using copying GC: we handle them
69 * with mark/sweep during major collections
70 * *) some objects need to not move even if they are small (interned strings, Type handles):
71 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
72 * PinnedChunks regions
78 *) we could have a function pointer in MonoClass to implement
79 customized write barriers for value types
81 *) investigate the stuff needed to advance a thread to a GC-safe
82 point (single-stepping, read from unmapped memory etc) and implement it.
83 This would enable us to inline allocations and write barriers, for example,
84 or at least parts of them, like the write barrier checks.
85 We may need this also for handling precise info on stacks, even simple things
86 as having uninitialized data on the stack and having to wait for the prolog
87 to zero it. Not an issue for the last frame that we scan conservatively.
88 We could always not trust the value in the slots anyway.
90 *) modify the jit to save info about references in stack locations:
91 this can be done just for locals as a start, so that at least
92 part of the stack is handled precisely.
94 *) test/fix endianess issues
96 *) Implement a card table as the write barrier instead of remembered
97 sets? Card tables are not easy to implement with our current
98 memory layout. We have several different kinds of major heap
99 objects: Small objects in regular blocks, small objects in pinned
100 chunks and LOS objects. If we just have a pointer we have no way
101 to tell which kind of object it points into, therefore we cannot
102 know where its card table is. The least we have to do to make
103 this happen is to get rid of write barriers for indirect stores.
106 *) Get rid of write barriers for indirect stores. We can do this by
107 telling the GC to wbarrier-register an object once we do an ldloca
108 or ldelema on it, and to unregister it once it's not used anymore
109 (it can only travel downwards on the stack). The problem with
110 unregistering is that it needs to happen eventually no matter
111 what, even if exceptions are thrown, the thread aborts, etc.
112 Rodrigo suggested that we could do only the registering part and
113 let the collector find out (pessimistically) when it's safe to
114 unregister, namely when the stack pointer of the thread that
115 registered the object is higher than it was when the registering
116 happened. This might make for a good first implementation to get
117 some data on performance.
119 *) Some sort of blacklist support? Blacklists is a concept from the
120 Boehm GC: if during a conservative scan we find pointers to an
121 area which we might use as heap, we mark that area as unusable, so
122 pointer retention by random pinning pointers is reduced.
124 *) experiment with max small object size (very small right now - 2kb,
125 because it's tied to the max freelist size)
127 *) add an option to mmap the whole heap in one chunk: it makes for many
128 simplifications in the checks (put the nursery at the top and just use a single
129 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
130 not flexible (too much of the address space may be used by default or we can't
131 increase the heap as needed) and we'd need a race-free mechanism to return memory
132 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
133 was written to, munmap is needed, but the following mmap may not find the same segment
136 *) memzero the major fragments after restarting the world and optionally a smaller
139 *) investigate having fragment zeroing threads
141 *) separate locks for finalization and other minor stuff to reduce
144 *) try a different copying order to improve memory locality
146 *) a thread abort after a store but before the write barrier will
147 prevent the write barrier from executing
149 *) specialized dynamically generated markers/copiers
151 *) Dynamically adjust TLAB size to the number of threads. If we have
152 too many threads that do allocation, we might need smaller TLABs,
153 and we might get better performance with larger TLABs if we only
154 have a handful of threads. We could sum up the space left in all
155 assigned TLABs and if that's more than some percentage of the
156 nursery size, reduce the TLAB size.
158 *) Explore placing unreachable objects on unused nursery memory.
159 Instead of memset'ng a region to zero, place an int[] covering it.
160 A good place to start is add_nursery_frag. The tricky thing here is
161 placing those objects atomically outside of a collection.
163 *) Allocation should use asymmetric Dekker synchronization:
164 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
165 This should help weak consistency archs.
172 #define _XOPEN_SOURCE
173 #define _DARWIN_C_SOURCE
179 #ifdef HAVE_PTHREAD_H
182 #ifdef HAVE_PTHREAD_NP_H
183 #include <pthread_np.h>
185 #ifdef HAVE_SEMAPHORE_H
186 #include <semaphore.h>
193 #include "metadata/sgen-gc.h"
194 #include "metadata/metadata-internals.h"
195 #include "metadata/class-internals.h"
196 #include "metadata/gc-internal.h"
197 #include "metadata/object-internals.h"
198 #include "metadata/threads.h"
199 #include "metadata/sgen-cardtable.h"
200 #include "metadata/sgen-protocol.h"
201 #include "metadata/sgen-archdep.h"
202 #include "metadata/sgen-bridge.h"
203 #include "metadata/sgen-memory-governor.h"
204 #include "metadata/sgen-hash-table.h"
205 #include "metadata/mono-gc.h"
206 #include "metadata/method-builder.h"
207 #include "metadata/profiler-private.h"
208 #include "metadata/monitor.h"
209 #include "metadata/mempool-internals.h"
210 #include "metadata/marshal.h"
211 #include "metadata/runtime.h"
212 #include "metadata/sgen-cardtable.h"
213 #include "metadata/sgen-pinning.h"
214 #include "metadata/sgen-workers.h"
215 #include "metadata/sgen-layout-stats.h"
216 #include "utils/mono-mmap.h"
217 #include "utils/mono-time.h"
218 #include "utils/mono-semaphore.h"
219 #include "utils/mono-counters.h"
220 #include "utils/mono-proclib.h"
221 #include "utils/mono-memory-model.h"
222 #include "utils/mono-logger-internal.h"
223 #include "utils/dtrace.h"
225 #include <mono/utils/mono-logger-internal.h>
226 #include <mono/utils/memcheck.h>
228 #if defined(__MACH__)
229 #include "utils/mach-support.h"
232 #define OPDEF(a,b,c,d,e,f,g,h,i,j) \
236 #include "mono/cil/opcode.def"
242 #undef pthread_create
244 #undef pthread_detach
247 * ######################################################################
248 * ######## Types and constants used by the GC.
249 * ######################################################################
252 /* 0 means not initialized, 1 is initialized, -1 means in progress */
253 static int gc_initialized = 0;
254 /* If set, check if we need to do something every X allocations */
255 gboolean has_per_allocation_action;
256 /* If set, do a heap check every X allocation */
257 guint32 verify_before_allocs = 0;
258 /* If set, do a minor collection before every X allocation */
259 guint32 collect_before_allocs = 0;
260 /* If set, do a whole heap check before each collection */
261 static gboolean whole_heap_check_before_collection = FALSE;
262 /* If set, do a heap consistency check before each minor collection */
263 static gboolean consistency_check_at_minor_collection = FALSE;
264 /* If set, do a mod union consistency check before each finishing collection pause */
265 static gboolean mod_union_consistency_check = FALSE;
266 /* If set, check whether mark bits are consistent after major collections */
267 static gboolean check_mark_bits_after_major_collection = FALSE;
268 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
269 static gboolean check_nursery_objects_pinned = FALSE;
270 /* If set, do a few checks when the concurrent collector is used */
271 static gboolean do_concurrent_checks = FALSE;
272 /* If set, check that there are no references to the domain left at domain unload */
273 static gboolean xdomain_checks = FALSE;
274 /* If not null, dump the heap after each collection into this file */
275 static FILE *heap_dump_file = NULL;
276 /* If set, mark stacks conservatively, even if precise marking is possible */
277 static gboolean conservative_stack_mark = FALSE;
278 /* If set, do a plausibility check on the scan_starts before and after
280 static gboolean do_scan_starts_check = FALSE;
283 * If the major collector is concurrent and this is FALSE, we will
284 * never initiate a synchronous major collection, unless requested via
287 static gboolean allow_synchronous_major = TRUE;
288 static gboolean disable_minor_collections = FALSE;
289 static gboolean disable_major_collections = FALSE;
290 static gboolean do_verify_nursery = FALSE;
291 static gboolean do_dump_nursery_content = FALSE;
292 static gboolean enable_nursery_canaries = FALSE;
294 #ifdef HEAVY_STATISTICS
295 guint64 stat_objects_alloced_degraded = 0;
296 guint64 stat_bytes_alloced_degraded = 0;
298 guint64 stat_copy_object_called_nursery = 0;
299 guint64 stat_objects_copied_nursery = 0;
300 guint64 stat_copy_object_called_major = 0;
301 guint64 stat_objects_copied_major = 0;
303 guint64 stat_scan_object_called_nursery = 0;
304 guint64 stat_scan_object_called_major = 0;
306 guint64 stat_slots_allocated_in_vain;
308 guint64 stat_nursery_copy_object_failed_from_space = 0;
309 guint64 stat_nursery_copy_object_failed_forwarded = 0;
310 guint64 stat_nursery_copy_object_failed_pinned = 0;
311 guint64 stat_nursery_copy_object_failed_to_space = 0;
313 static int stat_wbarrier_add_to_global_remset = 0;
314 static int stat_wbarrier_set_field = 0;
315 static int stat_wbarrier_set_arrayref = 0;
316 static int stat_wbarrier_arrayref_copy = 0;
317 static int stat_wbarrier_generic_store = 0;
318 static int stat_wbarrier_generic_store_atomic = 0;
319 static int stat_wbarrier_set_root = 0;
320 static int stat_wbarrier_value_copy = 0;
321 static int stat_wbarrier_object_copy = 0;
324 static guint64 stat_pinned_objects = 0;
326 static guint64 time_minor_pre_collection_fragment_clear = 0;
327 static guint64 time_minor_pinning = 0;
328 static guint64 time_minor_scan_remsets = 0;
329 static guint64 time_minor_scan_pinned = 0;
330 static guint64 time_minor_scan_roots = 0;
331 static guint64 time_minor_finish_gray_stack = 0;
332 static guint64 time_minor_fragment_creation = 0;
334 static guint64 time_major_pre_collection_fragment_clear = 0;
335 static guint64 time_major_pinning = 0;
336 static guint64 time_major_scan_pinned = 0;
337 static guint64 time_major_scan_roots = 0;
338 static guint64 time_major_scan_mod_union = 0;
339 static guint64 time_major_finish_gray_stack = 0;
340 static guint64 time_major_free_bigobjs = 0;
341 static guint64 time_major_los_sweep = 0;
342 static guint64 time_major_sweep = 0;
343 static guint64 time_major_fragment_creation = 0;
345 static guint64 time_max = 0;
347 static SGEN_TV_DECLARE (time_major_conc_collection_start);
348 static SGEN_TV_DECLARE (time_major_conc_collection_end);
350 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
351 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
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
370 SGEN_TV_DECLARE (sgen_init_timestamp);
372 #define ALIGN_TO(val,align) ((((guint64)val) + ((align) - 1)) & ~((align) - 1))
374 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
376 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
377 #define object_is_pinned SGEN_OBJECT_IS_PINNED
378 #define pin_object SGEN_PIN_OBJECT
380 #define ptr_in_nursery sgen_ptr_in_nursery
382 #define LOAD_VTABLE SGEN_LOAD_VTABLE
385 safe_name (void* obj)
387 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
388 return vt->klass->name;
392 nursery_canaries_enabled (void)
394 return enable_nursery_canaries;
397 #define safe_object_get_size sgen_safe_object_get_size
400 sgen_safe_name (void* obj)
402 return safe_name (obj);
406 * ######################################################################
407 * ######## Global data.
408 * ######################################################################
410 LOCK_DECLARE (gc_mutex);
411 gboolean sgen_try_free_some_memory;
413 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
415 static mword pagesize = 4096;
416 size_t degraded_mode = 0;
418 static mword bytes_pinned_from_failed_allocation = 0;
420 GCMemSection *nursery_section = NULL;
421 static volatile mword lowest_heap_address = ~(mword)0;
422 static volatile mword highest_heap_address = 0;
424 LOCK_DECLARE (sgen_interruption_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
513 #define ALIGN_UP SGEN_ALIGN_UP
515 #define MOVED_OBJECTS_NUM 64
516 static void *moved_objects [MOVED_OBJECTS_NUM];
517 static int moved_objects_idx = 0;
519 /* Vtable of the objects used to fill out nursery fragments before a collection */
520 static MonoVTable *array_fill_vtable;
522 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
523 MonoNativeThreadId main_gc_thread = NULL;
526 /*Object was pinned during the current collection*/
527 static mword objects_pinned;
530 * ######################################################################
531 * ######## Macros and function declarations.
532 * ######################################################################
535 typedef SgenGrayQueue GrayQueue;
537 /* forward declarations */
538 static void scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, ScanCopyContext ctx);
539 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
540 static void scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx);
541 static void report_finalizer_roots (void);
542 static void report_registered_roots (void);
544 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
545 static void finish_gray_stack (int generation, ScanCopyContext ctx);
547 void mono_gc_scan_for_specific_ref (MonoObject *key, gboolean precise);
550 static void init_stats (void);
552 static int mark_ephemerons_in_range (ScanCopyContext ctx);
553 static void clear_unreachable_ephemerons (ScanCopyContext ctx);
554 static void null_ephemerons_for_domain (MonoDomain *domain);
556 SgenMajorCollector major_collector;
557 SgenMinorCollector sgen_minor_collector;
558 /* FIXME: get rid of this */
559 static GrayQueue gray_queue;
561 static SgenRememberedSet remset;
563 /* The gray queue to use from the main collection thread. */
564 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
567 * The gray queue a worker job must use. If we're not parallel or
568 * concurrent, we use the main gray queue.
570 static SgenGrayQueue*
571 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
573 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
577 gray_queue_redirect (SgenGrayQueue *queue)
579 gboolean wake = FALSE;
582 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
585 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
590 g_assert (concurrent_collection_in_progress);
591 sgen_workers_ensure_awake ();
596 gray_queue_enable_redirect (SgenGrayQueue *queue)
598 if (!concurrent_collection_in_progress)
601 sgen_gray_queue_set_alloc_prepare (queue, gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
602 gray_queue_redirect (queue);
606 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
608 while (start < end) {
612 if (!*(void**)start) {
613 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
618 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
624 if ((MonoVTable*)SGEN_LOAD_VTABLE (obj) != array_fill_vtable) {
625 CHECK_CANARY_FOR_OBJECT (obj);
626 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
627 callback (obj, size, data);
628 CANARIFY_SIZE (size);
630 size = ALIGN_UP (safe_object_get_size ((MonoObject*)obj));
638 need_remove_object_for_domain (char *start, MonoDomain *domain)
640 if (mono_object_domain (start) == domain) {
641 SGEN_LOG (4, "Need to cleanup object %p", start);
642 binary_protocol_cleanup (start, (gpointer)LOAD_VTABLE (start), safe_object_get_size ((MonoObject*)start));
649 process_object_for_domain_clearing (char *start, MonoDomain *domain)
651 GCVTable *vt = (GCVTable*)LOAD_VTABLE (start);
652 if (vt->klass == mono_defaults.internal_thread_class)
653 g_assert (mono_object_domain (start) == mono_get_root_domain ());
654 /* The object could be a proxy for an object in the domain
656 #ifndef DISABLE_REMOTING
657 if (mono_defaults.real_proxy_class->supertypes && mono_class_has_parent_fast (vt->klass, mono_defaults.real_proxy_class)) {
658 MonoObject *server = ((MonoRealProxy*)start)->unwrapped_server;
660 /* The server could already have been zeroed out, so
661 we need to check for that, too. */
662 if (server && (!LOAD_VTABLE (server) || mono_object_domain (server) == domain)) {
663 SGEN_LOG (4, "Cleaning up remote pointer in %p to object %p", start, server);
664 ((MonoRealProxy*)start)->unwrapped_server = NULL;
671 clear_domain_process_object (char *obj, MonoDomain *domain)
675 process_object_for_domain_clearing (obj, domain);
676 remove = need_remove_object_for_domain (obj, domain);
678 if (remove && ((MonoObject*)obj)->synchronisation) {
679 void **dislink = mono_monitor_get_object_monitor_weak_link ((MonoObject*)obj);
681 sgen_register_disappearing_link (NULL, dislink, FALSE, TRUE);
688 clear_domain_process_minor_object_callback (char *obj, size_t size, MonoDomain *domain)
690 if (clear_domain_process_object (obj, domain)) {
691 CANARIFY_SIZE (size);
692 memset (obj, 0, size);
697 clear_domain_process_major_object_callback (char *obj, size_t size, MonoDomain *domain)
699 clear_domain_process_object (obj, domain);
703 clear_domain_free_major_non_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
705 if (need_remove_object_for_domain (obj, domain))
706 major_collector.free_non_pinned_object (obj, size);
710 clear_domain_free_major_pinned_object_callback (char *obj, size_t size, MonoDomain *domain)
712 if (need_remove_object_for_domain (obj, domain))
713 major_collector.free_pinned_object (obj, size);
717 * When appdomains are unloaded we can easily remove objects that have finalizers,
718 * but all the others could still be present in random places on the heap.
719 * We need a sweep to get rid of them even though it's going to be costly
721 * The reason we need to remove them is because we access the vtable and class
722 * structures to know the object size and the reference bitmap: once the domain is
723 * unloaded the point to random memory.
726 mono_gc_clear_domain (MonoDomain * domain)
728 LOSObject *bigobj, *prev;
733 binary_protocol_domain_unload_begin (domain);
737 if (concurrent_collection_in_progress)
738 sgen_perform_collection (0, GENERATION_OLD, "clear domain", TRUE);
739 g_assert (!concurrent_collection_in_progress);
741 major_collector.finish_sweeping ();
743 sgen_process_fin_stage_entries ();
744 sgen_process_dislink_stage_entries ();
746 sgen_clear_nursery_fragments ();
748 if (xdomain_checks && domain != mono_get_root_domain ()) {
749 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_NORMAL);
750 sgen_scan_for_registered_roots_in_domain (domain, ROOT_TYPE_WBARRIER);
751 sgen_check_for_xdomain_refs ();
754 /*Ephemerons and dislinks must be processed before LOS since they might end up pointing
755 to memory returned to the OS.*/
756 null_ephemerons_for_domain (domain);
758 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
759 sgen_null_links_for_domain (domain, i);
761 for (i = GENERATION_NURSERY; i < GENERATION_MAX; ++i)
762 sgen_remove_finalizers_for_domain (domain, i);
764 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
765 (IterateObjectCallbackFunc)clear_domain_process_minor_object_callback, domain, FALSE);
767 /* We need two passes over major and large objects because
768 freeing such objects might give their memory back to the OS
769 (in the case of large objects) or obliterate its vtable
770 (pinned objects with major-copying or pinned and non-pinned
771 objects with major-mark&sweep), but we might need to
772 dereference a pointer from an object to another object if
773 the first object is a proxy. */
774 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, (IterateObjectCallbackFunc)clear_domain_process_major_object_callback, domain);
775 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
776 clear_domain_process_object (bigobj->data, domain);
779 for (bigobj = los_object_list; bigobj;) {
780 if (need_remove_object_for_domain (bigobj->data, domain)) {
781 LOSObject *to_free = bigobj;
783 prev->next = bigobj->next;
785 los_object_list = bigobj->next;
786 bigobj = bigobj->next;
787 SGEN_LOG (4, "Freeing large object %p", bigobj->data);
788 sgen_los_free_object (to_free);
792 bigobj = bigobj->next;
794 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_non_pinned_object_callback, domain);
795 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, (IterateObjectCallbackFunc)clear_domain_free_major_pinned_object_callback, domain);
797 if (domain == mono_get_root_domain ()) {
798 sgen_pin_stats_print_class_stats ();
799 sgen_object_layout_dump (stdout);
802 sgen_restart_world (0, NULL);
804 binary_protocol_domain_unload_end (domain);
805 binary_protocol_flush_buffers (FALSE);
811 * sgen_add_to_global_remset:
813 * The global remset contains locations which point into newspace after
814 * a minor collection. This can happen if the objects they point to are pinned.
816 * LOCKING: If called from a parallel collector, the global remset
817 * lock must be held. For serial collectors that is not necessary.
820 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
822 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
824 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
826 if (!major_collector.is_concurrent) {
827 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
829 if (current_collection_generation == -1)
830 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
833 if (!object_is_pinned (obj))
834 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");
835 else if (sgen_cement_lookup_or_register (obj))
838 remset.record_pointer (ptr);
840 sgen_pin_stats_register_global_remset (obj);
842 SGEN_LOG (8, "Adding global remset for %p", ptr);
843 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
847 if (G_UNLIKELY (MONO_GC_GLOBAL_REMSET_ADD_ENABLED ())) {
848 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
849 MONO_GC_GLOBAL_REMSET_ADD ((mword)ptr, (mword)obj, sgen_safe_object_get_size (obj),
850 vt->klass->name_space, vt->klass->name);
856 * sgen_drain_gray_stack:
858 * Scan objects in the gray stack until the stack is empty. This should be called
859 * frequently after each object is copied, to achieve better locality and cache
862 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
866 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
868 ScanObjectFunc scan_func = ctx.ops->scan_object;
869 GrayQueue *queue = ctx.queue;
871 if (current_collection_generation == GENERATION_OLD && major_collector.drain_gray_stack)
872 return major_collector.drain_gray_stack (ctx);
876 for (i = 0; i != max_objs; ++i) {
879 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
882 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, safe_name (obj));
883 scan_func (obj, desc, queue);
885 } while (max_objs < 0);
890 * Addresses in the pin queue are already sorted. This function finds
891 * the object header for each address and pins the object. The
892 * addresses must be inside the nursery section. The (start of the)
893 * address array is overwritten with the addresses of the actually
894 * pinned objects. Return the number of pinned objects.
897 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
899 GCMemSection *section = nursery_section;
900 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
901 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
902 void *start_nursery = section->data;
903 void *end_nursery = section->next_data;
908 void *pinning_front = start_nursery;
910 void **definitely_pinned = start;
911 ScanObjectFunc scan_func = ctx.ops->scan_object;
912 SgenGrayQueue *queue = ctx.queue;
914 sgen_nursery_allocator_prepare_for_pinning ();
916 while (start < end) {
917 void *obj_to_pin = NULL;
918 size_t obj_to_pin_size = 0;
923 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
924 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
931 SGEN_LOG (5, "Considering pinning addr %p", addr);
932 /* We've already processed everything up to pinning_front. */
933 if (addr < pinning_front) {
939 * Find the closest scan start <= addr. We might search backward in the
940 * scan_starts array because entries might be NULL. In the worst case we
941 * start at start_nursery.
943 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
944 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
945 search_start = (void*)section->scan_starts [idx];
946 if (!search_start || search_start > addr) {
949 search_start = section->scan_starts [idx];
950 if (search_start && search_start <= addr)
953 if (!search_start || search_start > addr)
954 search_start = start_nursery;
958 * If the pinning front is closer than the scan start we found, start
959 * searching at the front.
961 if (search_start < pinning_front)
962 search_start = pinning_front;
965 * Now addr should be in an object a short distance from search_start.
967 * search_start must point to zeroed mem or point to an object.
970 size_t obj_size, canarified_obj_size;
973 if (!*(void**)search_start) {
974 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
975 /* The loop condition makes sure we don't overrun addr. */
979 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((MonoObject*)search_start));
982 * Filler arrays are marked by an invalid sync word. We don't
983 * consider them for pinning. They are not delimited by canaries,
986 if (((MonoObject*)search_start)->synchronisation != GINT_TO_POINTER (-1)) {
987 CHECK_CANARY_FOR_OBJECT (search_start);
988 CANARIFY_SIZE (canarified_obj_size);
990 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
991 /* This is the object we're looking for. */
992 obj_to_pin = search_start;
993 obj_to_pin_size = canarified_obj_size;
998 /* Skip to the next object */
999 search_start = (void*)((char*)search_start + canarified_obj_size);
1000 } while (search_start <= addr);
1002 /* We've searched past the address we were looking for. */
1004 pinning_front = search_start;
1005 goto next_pin_queue_entry;
1009 * We've found an object to pin. It might still be a dummy array, but we
1010 * can advance the pinning front in any case.
1012 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
1015 * If this is a dummy array marking the beginning of a nursery
1016 * fragment, we don't pin it.
1018 if (((MonoObject*)obj_to_pin)->synchronisation == GINT_TO_POINTER (-1))
1019 goto next_pin_queue_entry;
1022 * Finally - pin the object!
1024 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
1025 if (do_scan_objects) {
1026 scan_func (obj_to_pin, desc, queue);
1028 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
1029 obj_to_pin, *(void**)obj_to_pin, safe_name (obj_to_pin), count);
1030 binary_protocol_pin (obj_to_pin,
1031 (gpointer)LOAD_VTABLE (obj_to_pin),
1032 safe_object_get_size (obj_to_pin));
1034 #ifdef ENABLE_DTRACE
1035 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1036 int gen = sgen_ptr_in_nursery (obj_to_pin) ? GENERATION_NURSERY : GENERATION_OLD;
1037 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj_to_pin);
1038 MONO_GC_OBJ_PINNED ((mword)obj_to_pin,
1039 sgen_safe_object_get_size (obj_to_pin),
1040 vt->klass->name_space, vt->klass->name, gen);
1044 pin_object (obj_to_pin);
1045 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
1046 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
1047 definitely_pinned [count] = obj_to_pin;
1051 next_pin_queue_entry:
1055 //printf ("effective pinned: %d (at the end: %d)\n", count, (char*)end_nursery - (char*)last);
1056 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS) {
1057 GCRootReport report;
1059 for (idx = 0; idx < count; ++idx)
1060 add_profile_gc_root (&report, definitely_pinned [idx], MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
1061 notify_gc_roots (&report);
1063 stat_pinned_objects += count;
1068 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
1072 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
1075 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
1076 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
1080 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
1081 * when we can't promote an object because we're out of memory.
1084 sgen_pin_object (void *object, GrayQueue *queue)
1087 * All pinned objects are assumed to have been staged, so we need to stage as well.
1088 * Also, the count of staged objects shows that "late pinning" happened.
1090 sgen_pin_stage_ptr (object);
1092 SGEN_PIN_OBJECT (object);
1093 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
1096 sgen_pin_stats_register_object (object, safe_object_get_size (object));
1098 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
1100 #ifdef ENABLE_DTRACE
1101 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
1102 int gen = sgen_ptr_in_nursery (object) ? GENERATION_NURSERY : GENERATION_OLD;
1103 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (object);
1104 MONO_GC_OBJ_PINNED ((mword)object, sgen_safe_object_get_size (object), vt->klass->name_space, vt->klass->name, gen);
1109 /* Sort the addresses in array in increasing order.
1110 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
1113 sgen_sort_addresses (void **array, size_t size)
1118 for (i = 1; i < size; ++i) {
1121 size_t parent = (child - 1) / 2;
1123 if (array [parent] >= array [child])
1126 tmp = array [parent];
1127 array [parent] = array [child];
1128 array [child] = tmp;
1134 for (i = size - 1; i > 0; --i) {
1137 array [i] = array [0];
1143 while (root * 2 + 1 <= end) {
1144 size_t child = root * 2 + 1;
1146 if (child < end && array [child] < array [child + 1])
1148 if (array [root] >= array [child])
1152 array [root] = array [child];
1153 array [child] = tmp;
1161 * Scan the memory between start and end and queue values which could be pointers
1162 * to the area between start_nursery and end_nursery for later consideration.
1163 * Typically used for thread stacks.
1166 conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
1170 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
1171 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
1174 while (start < end) {
1175 if (*start >= start_nursery && *start < end_nursery) {
1177 * *start can point to the middle of an object
1178 * note: should we handle pointing at the end of an object?
1179 * pinning in C# code disallows pointing at the end of an object
1180 * but there is some small chance that an optimizing C compiler
1181 * may keep the only reference to an object by pointing
1182 * at the end of it. We ignore this small chance for now.
1183 * Pointers to the end of an object are indistinguishable
1184 * from pointers to the start of the next object in memory
1185 * so if we allow that we'd need to pin two objects...
1186 * We queue the pointer in an array, the
1187 * array will then be sorted and uniqued. This way
1188 * we can coalesce several pinning pointers and it should
1189 * be faster since we'd do a memory scan with increasing
1190 * addresses. Note: we can align the address to the allocation
1191 * alignment, so the unique process is more effective.
1193 mword addr = (mword)*start;
1194 addr &= ~(ALLOC_ALIGN - 1);
1195 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
1196 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
1197 sgen_pin_stage_ptr ((void*)addr);
1198 binary_protocol_pin_stage (start, (void*)addr);
1201 if (ptr_in_nursery ((void*)addr))
1202 sgen_pin_stats_register_address ((char*)addr, pin_type);
1207 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
1211 * The first thing we do in a collection is to identify pinned objects.
1212 * This function considers all the areas of memory that need to be
1213 * conservatively scanned.
1216 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
1220 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);
1221 /* objects pinned from the API are inside these roots */
1222 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
1223 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
1224 conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
1225 } SGEN_HASH_TABLE_FOREACH_END;
1226 /* now deal with the thread stacks
1227 * in the future we should be able to conservatively scan only:
1228 * *) the cpu registers
1229 * *) the unmanaged stack frames
1230 * *) the _last_ managed stack frame
1231 * *) pointers slots in managed frames
1233 scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
1237 unpin_objects_from_queue (SgenGrayQueue *queue)
1242 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
1245 g_assert (SGEN_OBJECT_IS_PINNED (addr));
1246 SGEN_UNPIN_OBJECT (addr);
1251 single_arg_user_copy_or_mark (void **obj, void *gc_data)
1253 ScanCopyContext *ctx = gc_data;
1254 ctx->ops->copy_or_mark_object (obj, ctx->queue);
1258 * The memory area from start_root to end_root contains pointers to objects.
1259 * Their position is precisely described by @desc (this means that the pointer
1260 * can be either NULL or the pointer to the start of an object).
1261 * This functions copies them to to_space updates them.
1263 * This function is not thread-safe!
1266 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
1268 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1269 SgenGrayQueue *queue = ctx.queue;
1271 switch (desc & ROOT_DESC_TYPE_MASK) {
1272 case ROOT_DESC_BITMAP:
1273 desc >>= ROOT_DESC_TYPE_SHIFT;
1275 if ((desc & 1) && *start_root) {
1276 copy_func (start_root, queue);
1277 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
1283 case ROOT_DESC_COMPLEX: {
1284 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1285 gsize bwords = (*bitmap_data) - 1;
1286 void **start_run = start_root;
1288 while (bwords-- > 0) {
1289 gsize bmap = *bitmap_data++;
1290 void **objptr = start_run;
1292 if ((bmap & 1) && *objptr) {
1293 copy_func (objptr, queue);
1294 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
1299 start_run += GC_BITS_PER_WORD;
1303 case ROOT_DESC_USER: {
1304 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1305 marker (start_root, single_arg_user_copy_or_mark, &ctx);
1308 case ROOT_DESC_RUN_LEN:
1309 g_assert_not_reached ();
1311 g_assert_not_reached ();
1316 reset_heap_boundaries (void)
1318 lowest_heap_address = ~(mword)0;
1319 highest_heap_address = 0;
1323 sgen_update_heap_boundaries (mword low, mword high)
1328 old = lowest_heap_address;
1331 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1334 old = highest_heap_address;
1337 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1341 * Allocate and setup the data structures needed to be able to allocate objects
1342 * in the nursery. The nursery is stored in nursery_section.
1345 alloc_nursery (void)
1347 GCMemSection *section;
1352 if (nursery_section)
1354 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1355 /* later we will alloc a larger area for the nursery but only activate
1356 * what we need. The rest will be used as expansion if we have too many pinned
1357 * objects in the existing nursery.
1359 /* FIXME: handle OOM */
1360 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1362 alloc_size = sgen_nursery_size;
1364 /* If there isn't enough space even for the nursery we should simply abort. */
1365 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1367 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1368 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1369 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 ());
1370 section->data = section->next_data = data;
1371 section->size = alloc_size;
1372 section->end_data = data + sgen_nursery_size;
1373 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1374 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1375 section->num_scan_start = scan_starts;
1377 nursery_section = section;
1379 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1383 mono_gc_get_nursery (int *shift_bits, size_t *size)
1385 *size = sgen_nursery_size;
1386 *shift_bits = DEFAULT_NURSERY_BITS;
1387 return sgen_get_nursery_start ();
1391 mono_gc_set_current_thread_appdomain (MonoDomain *domain)
1393 SgenThreadInfo *info = mono_thread_info_current ();
1395 /* Could be called from sgen_thread_unregister () with a NULL info */
1398 info->stopped_domain = domain;
1403 mono_gc_precise_stack_mark_enabled (void)
1405 return !conservative_stack_mark;
1409 mono_gc_get_logfile (void)
1411 return gc_debug_file;
1415 report_finalizer_roots_list (FinalizeReadyEntry *list)
1417 GCRootReport report;
1418 FinalizeReadyEntry *fin;
1421 for (fin = list; fin; fin = fin->next) {
1424 add_profile_gc_root (&report, fin->object, MONO_PROFILE_GC_ROOT_FINALIZER, 0);
1426 notify_gc_roots (&report);
1430 report_finalizer_roots (void)
1432 report_finalizer_roots_list (fin_ready_list);
1433 report_finalizer_roots_list (critical_fin_list);
1436 static GCRootReport *root_report;
1439 single_arg_report_root (void **obj, void *gc_data)
1442 add_profile_gc_root (root_report, *obj, MONO_PROFILE_GC_ROOT_OTHER, 0);
1446 precisely_report_roots_from (GCRootReport *report, void** start_root, void** end_root, mword desc)
1448 switch (desc & ROOT_DESC_TYPE_MASK) {
1449 case ROOT_DESC_BITMAP:
1450 desc >>= ROOT_DESC_TYPE_SHIFT;
1452 if ((desc & 1) && *start_root) {
1453 add_profile_gc_root (report, *start_root, MONO_PROFILE_GC_ROOT_OTHER, 0);
1459 case ROOT_DESC_COMPLEX: {
1460 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
1461 gsize bwords = (*bitmap_data) - 1;
1462 void **start_run = start_root;
1464 while (bwords-- > 0) {
1465 gsize bmap = *bitmap_data++;
1466 void **objptr = start_run;
1468 if ((bmap & 1) && *objptr) {
1469 add_profile_gc_root (report, *objptr, MONO_PROFILE_GC_ROOT_OTHER, 0);
1474 start_run += GC_BITS_PER_WORD;
1478 case ROOT_DESC_USER: {
1479 MonoGCRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
1480 root_report = report;
1481 marker (start_root, single_arg_report_root, NULL);
1484 case ROOT_DESC_RUN_LEN:
1485 g_assert_not_reached ();
1487 g_assert_not_reached ();
1492 report_registered_roots_by_type (int root_type)
1494 GCRootReport report;
1498 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1499 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1500 precisely_report_roots_from (&report, start_root, (void**)root->end_root, root->root_desc);
1501 } SGEN_HASH_TABLE_FOREACH_END;
1502 notify_gc_roots (&report);
1506 report_registered_roots (void)
1508 report_registered_roots_by_type (ROOT_TYPE_NORMAL);
1509 report_registered_roots_by_type (ROOT_TYPE_WBARRIER);
1513 scan_finalizer_entries (FinalizeReadyEntry *list, ScanCopyContext ctx)
1515 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1516 SgenGrayQueue *queue = ctx.queue;
1517 FinalizeReadyEntry *fin;
1519 for (fin = list; fin; fin = fin->next) {
1522 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", fin->object, safe_name (fin->object));
1523 copy_func (&fin->object, queue);
1528 generation_name (int generation)
1530 switch (generation) {
1531 case GENERATION_NURSERY: return "nursery";
1532 case GENERATION_OLD: return "old";
1533 default: g_assert_not_reached ();
1538 sgen_generation_name (int generation)
1540 return generation_name (generation);
1544 finish_gray_stack (int generation, ScanCopyContext ctx)
1548 int done_with_ephemerons, ephemeron_rounds = 0;
1549 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1550 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1551 SgenGrayQueue *queue = ctx.queue;
1554 * We copied all the reachable objects. Now it's the time to copy
1555 * the objects that were not referenced by the roots, but by the copied objects.
1556 * we built a stack of objects pointed to by gray_start: they are
1557 * additional roots and we may add more items as we go.
1558 * We loop until gray_start == gray_objects which means no more objects have
1559 * been added. Note this is iterative: no recursion is involved.
1560 * We need to walk the LO list as well in search of marked big objects
1561 * (use a flag since this is needed only on major collections). We need to loop
1562 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1563 * To achieve better cache locality and cache usage, we drain the gray stack
1564 * frequently, after each object is copied, and just finish the work here.
1566 sgen_drain_gray_stack (-1, ctx);
1568 SGEN_LOG (2, "%s generation done", generation_name (generation));
1571 Reset bridge data, we might have lingering data from a previous collection if this is a major
1572 collection trigged by minor overflow.
1574 We must reset the gathered bridges since their original block might be evacuated due to major
1575 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1577 if (sgen_need_bridge_processing ())
1578 sgen_bridge_reset_data ();
1581 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1582 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1583 * objects that are in fact reachable.
1585 done_with_ephemerons = 0;
1587 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1588 sgen_drain_gray_stack (-1, ctx);
1590 } while (!done_with_ephemerons);
1592 sgen_mark_togglerefs (start_addr, end_addr, ctx);
1594 if (sgen_need_bridge_processing ()) {
1595 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1596 sgen_drain_gray_stack (-1, ctx);
1597 sgen_collect_bridge_objects (generation, ctx);
1598 if (generation == GENERATION_OLD)
1599 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1602 Do the first bridge step here, as the collector liveness state will become useless after that.
1604 An important optimization is to only proccess the possibly dead part of the object graph and skip
1605 over all live objects as we transitively know everything they point must be alive too.
1607 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1609 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1610 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1613 sgen_bridge_processing_stw_step ();
1617 Make sure we drain the gray stack before processing disappearing links and finalizers.
1618 If we don't make sure it is empty we might wrongly see a live object as dead.
1620 sgen_drain_gray_stack (-1, ctx);
1623 We must clear weak links that don't track resurrection before processing object ready for
1624 finalization so they can be cleared before that.
1626 sgen_null_link_in_range (generation, TRUE, ctx);
1627 if (generation == GENERATION_OLD)
1628 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1631 /* walk the finalization queue and move also the objects that need to be
1632 * finalized: use the finalized objects as new roots so the objects they depend
1633 * on are also not reclaimed. As with the roots above, only objects in the nursery
1634 * are marked/copied.
1636 sgen_finalize_in_range (generation, ctx);
1637 if (generation == GENERATION_OLD)
1638 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1639 /* drain the new stack that might have been created */
1640 SGEN_LOG (6, "Precise scan of gray area post fin");
1641 sgen_drain_gray_stack (-1, ctx);
1644 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1646 done_with_ephemerons = 0;
1648 done_with_ephemerons = mark_ephemerons_in_range (ctx);
1649 sgen_drain_gray_stack (-1, ctx);
1651 } while (!done_with_ephemerons);
1654 * Clear ephemeron pairs with unreachable keys.
1655 * We pass the copy func so we can figure out if an array was promoted or not.
1657 clear_unreachable_ephemerons (ctx);
1660 * We clear togglerefs only after all possible chances of revival are done.
1661 * This is semantically more inline with what users expect and it allows for
1662 * user finalizers to correctly interact with TR objects.
1664 sgen_clear_togglerefs (start_addr, end_addr, ctx);
1667 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1670 * handle disappearing links
1671 * Note we do this after checking the finalization queue because if an object
1672 * survives (at least long enough to be finalized) we don't clear the link.
1673 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1674 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1677 g_assert (sgen_gray_object_queue_is_empty (queue));
1679 sgen_null_link_in_range (generation, FALSE, ctx);
1680 if (generation == GENERATION_OLD)
1681 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1682 if (sgen_gray_object_queue_is_empty (queue))
1684 sgen_drain_gray_stack (-1, ctx);
1687 g_assert (sgen_gray_object_queue_is_empty (queue));
1689 sgen_gray_object_queue_trim_free_list (queue);
1693 sgen_check_section_scan_starts (GCMemSection *section)
1696 for (i = 0; i < section->num_scan_start; ++i) {
1697 if (section->scan_starts [i]) {
1698 mword size = safe_object_get_size ((MonoObject*) section->scan_starts [i]);
1699 g_assert (size >= sizeof (MonoObject) && size <= MAX_SMALL_OBJ_SIZE);
1705 check_scan_starts (void)
1707 if (!do_scan_starts_check)
1709 sgen_check_section_scan_starts (nursery_section);
1710 major_collector.check_scan_starts ();
1714 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1718 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1719 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1720 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1721 } SGEN_HASH_TABLE_FOREACH_END;
1725 sgen_dump_occupied (char *start, char *end, char *section_start)
1727 fprintf (heap_dump_file, "<occupied offset=\"%td\" size=\"%td\"/>\n", start - section_start, end - start);
1731 sgen_dump_section (GCMemSection *section, const char *type)
1733 char *start = section->data;
1734 char *end = section->data + section->size;
1735 char *occ_start = NULL;
1737 char *old_start G_GNUC_UNUSED = NULL; /* just for debugging */
1739 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%lu\">\n", type, (unsigned long)section->size);
1741 while (start < end) {
1743 MonoClass *class G_GNUC_UNUSED;
1745 if (!*(void**)start) {
1747 sgen_dump_occupied (occ_start, start, section->data);
1750 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
1753 g_assert (start < section->next_data);
1758 vt = (GCVTable*)LOAD_VTABLE (start);
1761 size = ALIGN_UP (safe_object_get_size ((MonoObject*) start));
1764 fprintf (heap_dump_file, "<object offset=\"%d\" class=\"%s.%s\" size=\"%d\"/>\n",
1765 start - section->data,
1766 vt->klass->name_space, vt->klass->name,
1774 sgen_dump_occupied (occ_start, start, section->data);
1776 fprintf (heap_dump_file, "</section>\n");
1780 dump_object (MonoObject *obj, gboolean dump_location)
1782 static char class_name [1024];
1784 MonoClass *class = mono_object_class (obj);
1788 * Python's XML parser is too stupid to parse angle brackets
1789 * in strings, so we just ignore them;
1792 while (class->name [i] && j < sizeof (class_name) - 1) {
1793 if (!strchr ("<>\"", class->name [i]))
1794 class_name [j++] = class->name [i];
1797 g_assert (j < sizeof (class_name));
1800 fprintf (heap_dump_file, "<object class=\"%s.%s\" size=\"%zd\"",
1801 class->name_space, class_name,
1802 safe_object_get_size (obj));
1803 if (dump_location) {
1804 const char *location;
1805 if (ptr_in_nursery (obj))
1806 location = "nursery";
1807 else if (safe_object_get_size (obj) <= MAX_SMALL_OBJ_SIZE)
1811 fprintf (heap_dump_file, " location=\"%s\"", location);
1813 fprintf (heap_dump_file, "/>\n");
1817 dump_heap (const char *type, int num, const char *reason)
1822 fprintf (heap_dump_file, "<collection type=\"%s\" num=\"%d\"", type, num);
1824 fprintf (heap_dump_file, " reason=\"%s\"", reason);
1825 fprintf (heap_dump_file, ">\n");
1826 fprintf (heap_dump_file, "<other-mem-usage type=\"mempools\" size=\"%ld\"/>\n", mono_mempool_get_bytes_allocated ());
1827 sgen_dump_internal_mem_usage (heap_dump_file);
1828 fprintf (heap_dump_file, "<pinned type=\"stack\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_STACK));
1829 /* fprintf (heap_dump_file, "<pinned type=\"static-data\" bytes=\"%d\"/>\n", pinned_byte_counts [PIN_TYPE_STATIC_DATA]); */
1830 fprintf (heap_dump_file, "<pinned type=\"other\" bytes=\"%zu\"/>\n", sgen_pin_stats_get_pinned_byte_count (PIN_TYPE_OTHER));
1832 fprintf (heap_dump_file, "<pinned-objects>\n");
1833 for (list = sgen_pin_stats_get_object_list (); list; list = list->next)
1834 dump_object (list->obj, TRUE);
1835 fprintf (heap_dump_file, "</pinned-objects>\n");
1837 sgen_dump_section (nursery_section, "nursery");
1839 major_collector.dump_heap (heap_dump_file);
1841 fprintf (heap_dump_file, "<los>\n");
1842 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next)
1843 dump_object ((MonoObject*)bigobj->data, FALSE);
1844 fprintf (heap_dump_file, "</los>\n");
1846 fprintf (heap_dump_file, "</collection>\n");
1850 sgen_register_moved_object (void *obj, void *destination)
1852 g_assert (mono_profiler_events & MONO_PROFILE_GC_MOVES);
1854 if (moved_objects_idx == MOVED_OBJECTS_NUM) {
1855 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
1856 moved_objects_idx = 0;
1858 moved_objects [moved_objects_idx++] = obj;
1859 moved_objects [moved_objects_idx++] = destination;
1865 static gboolean inited = FALSE;
1870 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1872 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1873 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1874 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1875 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1876 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1877 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1879 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1880 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1881 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1882 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1883 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1884 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1885 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1886 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1887 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1888 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1890 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1892 #ifdef HEAVY_STATISTICS
1893 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_add_to_global_remset);
1894 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_field);
1895 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_arrayref);
1896 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_arrayref_copy);
1897 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store);
1898 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_generic_store_atomic);
1899 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_set_root);
1900 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_value_copy);
1901 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_INT, &stat_wbarrier_object_copy);
1903 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1904 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1906 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1907 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1908 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1909 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1911 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1912 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1914 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1916 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1917 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1918 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1919 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1921 sgen_nursery_allocator_init_heavy_stats ();
1922 sgen_alloc_init_heavy_stats ();
1930 reset_pinned_from_failed_allocation (void)
1932 bytes_pinned_from_failed_allocation = 0;
1936 sgen_set_pinned_from_failed_allocation (mword objsize)
1938 bytes_pinned_from_failed_allocation += objsize;
1942 sgen_collection_is_concurrent (void)
1944 switch (current_collection_generation) {
1945 case GENERATION_NURSERY:
1947 case GENERATION_OLD:
1948 return concurrent_collection_in_progress;
1950 g_error ("Invalid current generation %d", current_collection_generation);
1955 sgen_concurrent_collection_in_progress (void)
1957 return concurrent_collection_in_progress;
1961 SgenThreadPoolJob job;
1962 SgenObjectOperations *ops;
1966 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
1968 WorkerData *worker_data = worker_data_untyped;
1969 ScanJob *job_data = (ScanJob*)job;
1970 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1971 remset.scan_remsets (ctx);
1975 SgenThreadPoolJob job;
1976 SgenObjectOperations *ops;
1980 } ScanFromRegisteredRootsJob;
1983 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1985 WorkerData *worker_data = worker_data_untyped;
1986 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1987 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1989 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1993 SgenThreadPoolJob job;
1994 SgenObjectOperations *ops;
1997 } ScanThreadDataJob;
2000 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
2002 WorkerData *worker_data = worker_data_untyped;
2003 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
2004 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
2006 scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
2010 SgenThreadPoolJob job;
2011 SgenObjectOperations *ops;
2012 FinalizeReadyEntry *list;
2013 } ScanFinalizerEntriesJob;
2016 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
2018 WorkerData *worker_data = worker_data_untyped;
2019 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
2020 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
2022 scan_finalizer_entries (job_data->list, ctx);
2026 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
2028 WorkerData *worker_data = worker_data_untyped;
2029 ScanJob *job_data = (ScanJob*)job;
2030 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
2032 g_assert (concurrent_collection_in_progress);
2033 major_collector.scan_card_table (TRUE, ctx);
2037 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
2039 WorkerData *worker_data = worker_data_untyped;
2040 ScanJob *job_data = (ScanJob*)job;
2041 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
2043 g_assert (concurrent_collection_in_progress);
2044 sgen_los_scan_card_table (TRUE, ctx);
2048 verify_scan_starts (char *start, char *end)
2052 for (i = 0; i < nursery_section->num_scan_start; ++i) {
2053 char *addr = nursery_section->scan_starts [i];
2054 if (addr > start && addr < end)
2055 SGEN_LOG (1, "NFC-BAD SCAN START [%zu] %p for obj [%p %p]", i, addr, start, end);
2060 verify_nursery (void)
2062 char *start, *end, *cur, *hole_start;
2064 if (!do_verify_nursery)
2067 if (nursery_canaries_enabled ())
2068 SGEN_LOG (1, "Checking nursery canaries...");
2070 /*This cleans up unused fragments */
2071 sgen_nursery_allocator_prepare_for_pinning ();
2073 hole_start = start = cur = sgen_get_nursery_start ();
2074 end = sgen_get_nursery_end ();
2079 if (!*(void**)cur) {
2080 cur += sizeof (void*);
2084 if (object_is_forwarded (cur))
2085 SGEN_LOG (1, "FORWARDED OBJ %p", cur);
2086 else if (object_is_pinned (cur))
2087 SGEN_LOG (1, "PINNED OBJ %p", cur);
2089 ss = safe_object_get_size ((MonoObject*)cur);
2090 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2091 verify_scan_starts (cur, cur + size);
2092 if (do_dump_nursery_content) {
2093 if (cur > hole_start)
2094 SGEN_LOG (1, "HOLE [%p %p %d]", hole_start, cur, (int)(cur - hole_start));
2095 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 ());
2097 if (nursery_canaries_enabled () && (MonoVTable*)SGEN_LOAD_VTABLE (cur) != array_fill_vtable) {
2098 CHECK_CANARY_FOR_OBJECT (cur);
2099 CANARIFY_SIZE (size);
2107 * Checks that no objects in the nursery are fowarded or pinned. This
2108 * is a precondition to restarting the mutator while doing a
2109 * concurrent collection. Note that we don't clear fragments because
2110 * we depend on that having happened earlier.
2113 check_nursery_is_clean (void)
2117 cur = sgen_get_nursery_start ();
2118 end = sgen_get_nursery_end ();
2123 if (!*(void**)cur) {
2124 cur += sizeof (void*);
2128 g_assert (!object_is_forwarded (cur));
2129 g_assert (!object_is_pinned (cur));
2131 size = ALIGN_UP (safe_object_get_size ((MonoObject*)cur));
2132 verify_scan_starts (cur, cur + size);
2139 init_gray_queue (void)
2141 if (sgen_collection_is_concurrent ())
2142 sgen_workers_init_distribute_gray_queue ();
2143 sgen_gray_object_queue_init (&gray_queue, NULL);
2147 enqueue_scan_from_roots_jobs (char *heap_start, char *heap_end, SgenObjectOperations *ops)
2149 ScanFromRegisteredRootsJob *scrrj;
2150 ScanThreadDataJob *stdj;
2151 ScanFinalizerEntriesJob *sfej;
2153 /* registered roots, this includes static fields */
2155 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
2157 scrrj->heap_start = heap_start;
2158 scrrj->heap_end = heap_end;
2159 scrrj->root_type = ROOT_TYPE_NORMAL;
2160 sgen_workers_enqueue_job (&scrrj->job);
2162 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
2164 scrrj->heap_start = heap_start;
2165 scrrj->heap_end = heap_end;
2166 scrrj->root_type = ROOT_TYPE_WBARRIER;
2167 sgen_workers_enqueue_job (&scrrj->job);
2171 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
2172 stdj->heap_start = heap_start;
2173 stdj->heap_end = heap_end;
2174 sgen_workers_enqueue_job (&stdj->job);
2176 /* Scan the list of objects ready for finalization. */
2178 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
2179 sfej->list = fin_ready_list;
2181 sgen_workers_enqueue_job (&sfej->job);
2183 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
2184 sfej->list = critical_fin_list;
2186 sgen_workers_enqueue_job (&sfej->job);
2190 * Perform a nursery collection.
2192 * Return whether any objects were late-pinned due to being out of memory.
2195 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
2197 gboolean needs_major;
2198 size_t max_garbage_amount;
2200 mword fragment_total;
2202 SgenObjectOperations *object_ops = &sgen_minor_collector.serial_ops;
2203 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gray_queue);
2207 if (disable_minor_collections)
2210 TV_GETTIME (last_minor_collection_start_tv);
2211 atv = last_minor_collection_start_tv;
2213 MONO_GC_BEGIN (GENERATION_NURSERY);
2214 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
2218 #ifndef DISABLE_PERFCOUNTERS
2219 mono_perfcounters->gc_collections0++;
2222 current_collection_generation = GENERATION_NURSERY;
2224 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
2226 reset_pinned_from_failed_allocation ();
2228 check_scan_starts ();
2230 sgen_nursery_alloc_prepare_for_minor ();
2234 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
2235 /* FIXME: optimize later to use the higher address where an object can be present */
2236 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
2238 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", gc_stats.minor_gc_count, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ()));
2239 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
2240 g_assert (nursery_section->size >= max_garbage_amount);
2242 /* world must be stopped already */
2244 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2246 if (xdomain_checks) {
2247 sgen_clear_nursery_fragments ();
2248 sgen_check_for_xdomain_refs ();
2251 nursery_section->next_data = nursery_next;
2253 major_collector.start_nursery_collection ();
2255 sgen_memgov_minor_collection_start ();
2259 gc_stats.minor_gc_count ++;
2261 if (whole_heap_check_before_collection) {
2262 sgen_clear_nursery_fragments ();
2263 sgen_check_whole_heap (finish_up_concurrent_mark);
2265 if (consistency_check_at_minor_collection)
2266 sgen_check_consistency ();
2268 MONO_GC_CHECKPOINT_1 (GENERATION_NURSERY);
2270 sgen_process_fin_stage_entries ();
2271 sgen_process_dislink_stage_entries ();
2273 MONO_GC_CHECKPOINT_2 (GENERATION_NURSERY);
2275 /* pin from pinned handles */
2276 sgen_init_pinning ();
2277 mono_profiler_gc_event (MONO_GC_EVENT_MARK_START, 0);
2278 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
2279 /* pin cemented objects */
2280 sgen_pin_cemented_objects ();
2281 /* identify pinned objects */
2282 sgen_optimize_pin_queue ();
2283 sgen_pinning_setup_section (nursery_section);
2285 pin_objects_in_nursery (FALSE, ctx);
2286 sgen_pinning_trim_queue_to_section (nursery_section);
2289 time_minor_pinning += TV_ELAPSED (btv, atv);
2290 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
2291 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2293 MONO_GC_CHECKPOINT_3 (GENERATION_NURSERY);
2296 * FIXME: When we finish a concurrent collection we do a nursery collection first,
2297 * as part of which we scan the card table. Then, later, we scan the mod union
2298 * cardtable. We should only have to do one.
2300 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
2301 sj->ops = object_ops;
2302 sgen_workers_enqueue_job (&sj->job);
2304 /* we don't have complete write barrier yet, so we scan all the old generation sections */
2306 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
2307 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
2309 MONO_GC_CHECKPOINT_4 (GENERATION_NURSERY);
2311 sgen_drain_gray_stack (-1, ctx);
2313 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2314 report_registered_roots ();
2315 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2316 report_finalizer_roots ();
2318 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
2320 MONO_GC_CHECKPOINT_5 (GENERATION_NURSERY);
2322 enqueue_scan_from_roots_jobs (sgen_get_nursery_start (), nursery_next, object_ops);
2325 time_minor_scan_roots += TV_ELAPSED (atv, btv);
2327 MONO_GC_CHECKPOINT_6 (GENERATION_NURSERY);
2328 MONO_GC_CHECKPOINT_7 (GENERATION_NURSERY);
2329 MONO_GC_CHECKPOINT_8 (GENERATION_NURSERY);
2331 finish_gray_stack (GENERATION_NURSERY, ctx);
2333 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
2334 mono_profiler_gc_event (MONO_GC_EVENT_MARK_END, 0);
2336 MONO_GC_CHECKPOINT_9 (GENERATION_NURSERY);
2338 if (objects_pinned) {
2339 sgen_optimize_pin_queue ();
2340 sgen_pinning_setup_section (nursery_section);
2343 /* walk the pin_queue, build up the fragment list of free memory, unmark
2344 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2347 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_START, 0);
2348 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
2349 if (!fragment_total)
2352 /* Clear TLABs for all threads */
2353 sgen_clear_tlabs ();
2355 mono_profiler_gc_event (MONO_GC_EVENT_RECLAIM_END, 0);
2357 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
2358 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
2360 if (consistency_check_at_minor_collection)
2361 sgen_check_major_refs ();
2363 major_collector.finish_nursery_collection ();
2365 TV_GETTIME (last_minor_collection_end_tv);
2366 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2369 dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
2371 /* prepare the pin queue for the next collection */
2372 sgen_finish_pinning ();
2373 if (fin_ready_list || critical_fin_list) {
2374 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2375 mono_gc_finalize_notify ();
2377 sgen_pin_stats_reset ();
2378 /* clear cemented hash */
2379 sgen_cement_clear_below_threshold ();
2381 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2383 remset.finish_minor_collection ();
2385 check_scan_starts ();
2387 binary_protocol_flush_buffers (FALSE);
2389 sgen_memgov_minor_collection_end ();
2391 /*objects are late pinned because of lack of memory, so a major is a good call*/
2392 needs_major = objects_pinned > 0;
2393 current_collection_generation = -1;
2396 MONO_GC_END (GENERATION_NURSERY);
2397 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
2399 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2400 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
2406 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
2409 * This is called on all objects in the nursery, including pinned ones, so we need
2410 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
2412 ctx->ops->scan_object (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
2416 scan_nursery_objects (ScanCopyContext ctx)
2418 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
2419 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
2423 COPY_OR_MARK_FROM_ROOTS_SERIAL,
2424 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
2425 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
2426 } CopyOrMarkFromRootsMode;
2429 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMode mode, gboolean scan_whole_nursery, SgenObjectOperations *object_ops)
2434 /* FIXME: only use these values for the precise scan
2435 * note that to_space pointers should be excluded anyway...
2437 char *heap_start = NULL;
2438 char *heap_end = (char*)-1;
2439 gboolean profile_roots = mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS;
2440 GCRootReport root_report = { 0 };
2441 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, WORKERS_DISTRIBUTE_GRAY_QUEUE);
2442 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
2444 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
2446 if (scan_whole_nursery)
2447 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "Scanning whole nursery only makes sense when we're finishing a concurrent collection.");
2450 /*This cleans up unused fragments */
2451 sgen_nursery_allocator_prepare_for_pinning ();
2453 if (do_concurrent_checks)
2454 check_nursery_is_clean ();
2456 /* The concurrent collector doesn't touch the nursery. */
2457 sgen_nursery_alloc_prepare_for_major ();
2464 /* Pinning depends on this */
2465 sgen_clear_nursery_fragments ();
2467 if (whole_heap_check_before_collection)
2468 sgen_check_whole_heap (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT);
2471 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
2473 if (!sgen_collection_is_concurrent ())
2474 nursery_section->next_data = sgen_get_nursery_end ();
2475 /* we should also coalesce scanning from sections close to each other
2476 * and deal with pointers outside of the sections later.
2481 if (xdomain_checks) {
2482 sgen_clear_nursery_fragments ();
2483 sgen_check_for_xdomain_refs ();
2487 /* Remsets are not useful for a major collection */
2488 remset.clear_cards ();
2491 sgen_process_fin_stage_entries ();
2492 sgen_process_dislink_stage_entries ();
2495 sgen_init_pinning ();
2496 SGEN_LOG (6, "Collecting pinned addresses");
2497 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
2499 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
2500 if (major_collector.is_concurrent) {
2502 * The concurrent major collector cannot evict
2503 * yet, so we need to pin cemented objects to
2504 * not break some asserts.
2506 * FIXME: We could evict now!
2508 sgen_pin_cemented_objects ();
2512 sgen_optimize_pin_queue ();
2515 * pin_queue now contains all candidate pointers, sorted and
2516 * uniqued. We must do two passes now to figure out which
2517 * objects are pinned.
2519 * The first is to find within the pin_queue the area for each
2520 * section. This requires that the pin_queue be sorted. We
2521 * also process the LOS objects and pinned chunks here.
2523 * The second, destructive, pass is to reduce the section
2524 * areas to pointers to the actually pinned objects.
2526 SGEN_LOG (6, "Pinning from sections");
2527 /* first pass for the sections */
2528 sgen_find_section_pin_queue_start_end (nursery_section);
2529 /* identify possible pointers to the insize of large objects */
2530 SGEN_LOG (6, "Pinning from large objects");
2531 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
2533 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
2534 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((MonoObject*)(bigobj->data))));
2536 #ifdef ENABLE_DTRACE
2537 if (G_UNLIKELY (MONO_GC_OBJ_PINNED_ENABLED ())) {
2538 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (bigobj->data);
2539 MONO_GC_OBJ_PINNED ((mword)bigobj->data, sgen_safe_object_get_size ((MonoObject*)bigobj->data), vt->klass->name_space, vt->klass->name, GENERATION_OLD);
2543 if (sgen_los_object_is_pinned (bigobj->data)) {
2544 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
2547 sgen_los_pin_object (bigobj->data);
2548 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
2549 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
2550 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((MonoObject*) bigobj->data));
2551 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));
2554 add_profile_gc_root (&root_report, bigobj->data, MONO_PROFILE_GC_ROOT_PINNING | MONO_PROFILE_GC_ROOT_MISC, 0);
2558 notify_gc_roots (&root_report);
2559 /* second pass for the sections */
2562 * Concurrent mark never follows references into the nursery. In the start and
2563 * finish pauses we must scan live nursery objects, though.
2565 * In the finish pause we do this conservatively by scanning all nursery objects.
2566 * Previously we would only scan pinned objects here. We assumed that all objects
2567 * that were pinned during the nursery collection immediately preceding this finish
2568 * mark would be pinned again here. Due to the way we get the stack end for the GC
2569 * thread, however, that's not necessarily the case: we scan part of the stack used
2570 * by the GC itself, which changes constantly, so pinning isn't entirely
2573 * The split nursery also complicates things because non-pinned objects can survive
2574 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
2576 * In the future we shouldn't do a preceding nursery collection at all and instead
2577 * do the finish pause with promotion from the nursery.
2579 * A further complication arises when we have late-pinned objects from the preceding
2580 * nursery collection. Those are the result of being out of memory when trying to
2581 * evacuate objects. They won't be found from the roots, so we just scan the whole
2584 * Non-concurrent mark evacuates from the nursery, so it's
2585 * sufficient to just scan pinned nursery objects.
2587 if (scan_whole_nursery || mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT || (concurrent && sgen_minor_collector.is_split)) {
2588 scan_nursery_objects (ctx);
2590 pin_objects_in_nursery (concurrent, ctx);
2591 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
2592 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
2595 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2596 if (old_next_pin_slot)
2597 *old_next_pin_slot = sgen_get_pinned_count ();
2600 time_major_pinning += TV_ELAPSED (atv, btv);
2601 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
2602 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
2604 major_collector.init_to_space ();
2607 * The concurrent collector doesn't move objects, neither on
2608 * the major heap nor in the nursery, so we can mark even
2609 * before pinning has finished. For the non-concurrent
2610 * collector we start the workers after pinning.
2612 if (mode != COPY_OR_MARK_FROM_ROOTS_SERIAL) {
2613 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
2614 sgen_workers_start_all_workers (object_ops);
2615 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
2618 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2619 main_gc_thread = mono_native_thread_self ();
2622 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2623 report_registered_roots ();
2625 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2627 if (mono_profiler_get_events () & MONO_PROFILE_GC_ROOTS)
2628 report_finalizer_roots ();
2631 * FIXME: is this the right context? It doesn't seem to contain a copy function
2632 * unless we're concurrent.
2634 enqueue_scan_from_roots_jobs (heap_start, heap_end, object_ops);
2637 time_major_scan_roots += TV_ELAPSED (atv, btv);
2639 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
2642 /* Mod union card table */
2643 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ScanJob));
2644 sj->ops = object_ops;
2645 sgen_workers_enqueue_job (&sj->job);
2647 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ScanJob));
2648 sj->ops = object_ops;
2649 sgen_workers_enqueue_job (&sj->job);
2652 time_major_scan_mod_union += TV_ELAPSED (btv, atv);
2657 major_finish_copy_or_mark (void)
2659 if (!concurrent_collection_in_progress)
2663 * Prepare the pin queue for the next collection. Since pinning runs on the worker
2664 * threads we must wait for the jobs to finish before we can reset it.
2666 sgen_workers_wait_for_jobs_finished ();
2667 sgen_finish_pinning ();
2669 sgen_pin_stats_reset ();
2671 if (do_concurrent_checks)
2672 check_nursery_is_clean ();
2676 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
2678 SgenObjectOperations *object_ops;
2680 MONO_GC_BEGIN (GENERATION_OLD);
2681 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2683 current_collection_generation = GENERATION_OLD;
2684 #ifndef DISABLE_PERFCOUNTERS
2685 mono_perfcounters->gc_collections1++;
2688 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2690 sgen_cement_reset ();
2693 g_assert (major_collector.is_concurrent);
2694 concurrent_collection_in_progress = TRUE;
2696 object_ops = &major_collector.major_ops_concurrent_start;
2698 object_ops = &major_collector.major_ops_serial;
2701 reset_pinned_from_failed_allocation ();
2703 sgen_memgov_major_collection_start ();
2705 //count_ref_nonref_objs ();
2706 //consistency_check ();
2708 check_scan_starts ();
2711 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2712 gc_stats.major_gc_count ++;
2714 if (major_collector.start_major_collection)
2715 major_collector.start_major_collection ();
2717 major_copy_or_mark_from_roots (old_next_pin_slot, concurrent ? COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT : COPY_OR_MARK_FROM_ROOTS_SERIAL, FALSE, object_ops);
2718 major_finish_copy_or_mark ();
2722 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean forced, gboolean scan_whole_nursery)
2724 ScannedObjectCounts counts;
2725 SgenObjectOperations *object_ops;
2731 if (concurrent_collection_in_progress) {
2732 object_ops = &major_collector.major_ops_concurrent_finish;
2734 major_copy_or_mark_from_roots (NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, scan_whole_nursery, object_ops);
2736 major_finish_copy_or_mark ();
2738 sgen_workers_join ();
2740 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2742 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2743 main_gc_thread = NULL;
2746 if (do_concurrent_checks)
2747 check_nursery_is_clean ();
2749 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2750 object_ops = &major_collector.major_ops_serial;
2754 * The workers have stopped so we need to finish gray queue
2755 * work that might result from finalization in the main GC
2756 * thread. Redirection must therefore be turned off.
2758 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2759 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2761 /* all the objects in the heap */
2762 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gray_queue));
2764 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2766 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2768 if (objects_pinned) {
2769 g_assert (!concurrent_collection_in_progress);
2772 * This is slow, but we just OOM'd.
2774 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2775 * queue is laid out at this point.
2777 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2779 * We need to reestablish all pinned nursery objects in the pin queue
2780 * because they're needed for fragment creation. Unpinning happens by
2781 * walking the whole queue, so it's not necessary to reestablish where major
2782 * heap block pins are - all we care is that they're still in there
2785 sgen_optimize_pin_queue ();
2786 sgen_find_section_pin_queue_start_end (nursery_section);
2790 reset_heap_boundaries ();
2791 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2793 if (!concurrent_collection_in_progress) {
2794 /* walk the pin_queue, build up the fragment list of free memory, unmark
2795 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2798 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2801 /* prepare the pin queue for the next collection */
2802 sgen_finish_pinning ();
2804 /* Clear TLABs for all threads */
2805 sgen_clear_tlabs ();
2807 sgen_pin_stats_reset ();
2810 sgen_cement_clear_below_threshold ();
2812 if (check_mark_bits_after_major_collection)
2813 sgen_check_heap_marked (concurrent_collection_in_progress);
2816 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2818 MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
2821 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2826 time_major_los_sweep += TV_ELAPSED (atv, btv);
2828 major_collector.sweep ();
2830 MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
2833 time_major_sweep += TV_ELAPSED (btv, atv);
2836 dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2838 if (fin_ready_list || critical_fin_list) {
2839 SGEN_LOG (4, "Finalizer-thread wakeup: ready %d", num_ready_finalizers);
2840 mono_gc_finalize_notify ();
2843 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2845 sgen_memgov_major_collection_end (forced);
2846 current_collection_generation = -1;
2848 memset (&counts, 0, sizeof (ScannedObjectCounts));
2849 major_collector.finish_major_collection (&counts);
2851 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2853 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2854 if (concurrent_collection_in_progress)
2855 concurrent_collection_in_progress = FALSE;
2857 check_scan_starts ();
2859 binary_protocol_flush_buffers (FALSE);
2861 //consistency_check ();
2863 MONO_GC_END (GENERATION_OLD);
2864 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2868 major_do_collection (const char *reason, gboolean forced)
2870 TV_DECLARE (time_start);
2871 TV_DECLARE (time_end);
2872 size_t old_next_pin_slot;
2874 if (disable_major_collections)
2877 if (major_collector.get_and_reset_num_major_objects_marked) {
2878 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2879 g_assert (!num_marked);
2882 /* world must be stopped already */
2883 TV_GETTIME (time_start);
2885 major_start_collection (FALSE, &old_next_pin_slot);
2886 major_finish_collection (reason, old_next_pin_slot, forced, FALSE);
2888 TV_GETTIME (time_end);
2889 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2891 /* FIXME: also report this to the user, preferably in gc-end. */
2892 if (major_collector.get_and_reset_num_major_objects_marked)
2893 major_collector.get_and_reset_num_major_objects_marked ();
2895 return bytes_pinned_from_failed_allocation > 0;
2899 major_start_concurrent_collection (const char *reason)
2901 TV_DECLARE (time_start);
2902 TV_DECLARE (time_end);
2903 long long num_objects_marked;
2905 if (disable_major_collections)
2908 TV_GETTIME (time_start);
2909 SGEN_TV_GETTIME (time_major_conc_collection_start);
2911 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2912 g_assert (num_objects_marked == 0);
2914 MONO_GC_CONCURRENT_START_BEGIN (GENERATION_OLD);
2915 binary_protocol_concurrent_start ();
2917 // FIXME: store reason and pass it when finishing
2918 major_start_collection (TRUE, NULL);
2920 gray_queue_redirect (&gray_queue);
2922 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2923 MONO_GC_CONCURRENT_START_END (GENERATION_OLD, num_objects_marked);
2925 TV_GETTIME (time_end);
2926 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2928 current_collection_generation = -1;
2932 * Returns whether the major collection has finished.
2935 major_should_finish_concurrent_collection (void)
2937 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
2938 return sgen_workers_all_done ();
2942 major_update_concurrent_collection (void)
2944 TV_DECLARE (total_start);
2945 TV_DECLARE (total_end);
2947 TV_GETTIME (total_start);
2949 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
2950 binary_protocol_concurrent_update ();
2952 major_collector.update_cardtable_mod_union ();
2953 sgen_los_update_cardtable_mod_union ();
2955 MONO_GC_CONCURRENT_UPDATE_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
2957 TV_GETTIME (total_end);
2958 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2962 major_finish_concurrent_collection (gboolean forced)
2964 TV_DECLARE (total_start);
2965 TV_DECLARE (total_end);
2966 gboolean late_pinned;
2967 SgenGrayQueue unpin_queue;
2968 memset (&unpin_queue, 0, sizeof (unpin_queue));
2970 TV_GETTIME (total_start);
2972 MONO_GC_CONCURRENT_UPDATE_FINISH_BEGIN (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
2973 binary_protocol_concurrent_finish ();
2976 * The major collector can add global remsets which are processed in the finishing
2977 * nursery collection, below. That implies that the workers must have finished
2978 * marking before the nursery collection is allowed to run, otherwise we might miss
2981 sgen_workers_wait ();
2983 SGEN_TV_GETTIME (time_major_conc_collection_end);
2984 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2986 major_collector.update_cardtable_mod_union ();
2987 sgen_los_update_cardtable_mod_union ();
2989 late_pinned = collect_nursery (&unpin_queue, TRUE);
2991 if (mod_union_consistency_check)
2992 sgen_check_mod_union_consistency ();
2994 current_collection_generation = GENERATION_OLD;
2995 major_finish_collection ("finishing", -1, forced, late_pinned);
2997 if (whole_heap_check_before_collection)
2998 sgen_check_whole_heap (FALSE);
3000 unpin_objects_from_queue (&unpin_queue);
3001 sgen_gray_object_queue_deinit (&unpin_queue);
3003 MONO_GC_CONCURRENT_FINISH_END (GENERATION_OLD, major_collector.get_and_reset_num_major_objects_marked ());
3005 TV_GETTIME (total_end);
3006 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
3008 current_collection_generation = -1;
3012 * Ensure an allocation request for @size will succeed by freeing enough memory.
3014 * LOCKING: The GC lock MUST be held.
3017 sgen_ensure_free_space (size_t size)
3019 int generation_to_collect = -1;
3020 const char *reason = NULL;
3022 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
3023 if (sgen_need_major_collection (size)) {
3024 reason = "LOS overflow";
3025 generation_to_collect = GENERATION_OLD;
3028 if (degraded_mode) {
3029 if (sgen_need_major_collection (size)) {
3030 reason = "Degraded mode overflow";
3031 generation_to_collect = GENERATION_OLD;
3033 } else if (sgen_need_major_collection (size)) {
3034 reason = "Minor allowance";
3035 generation_to_collect = GENERATION_OLD;
3037 generation_to_collect = GENERATION_NURSERY;
3038 reason = "Nursery full";
3042 if (generation_to_collect == -1) {
3043 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
3044 generation_to_collect = GENERATION_OLD;
3045 reason = "Finish concurrent collection";
3049 if (generation_to_collect == -1)
3051 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
3055 * LOCKING: Assumes the GC lock is held.
3058 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
3060 TV_DECLARE (gc_start);
3061 TV_DECLARE (gc_end);
3062 TV_DECLARE (gc_total_start);
3063 TV_DECLARE (gc_total_end);
3064 GGTimingInfo infos [2];
3065 int overflow_generation_to_collect = -1;
3066 int oldest_generation_collected = generation_to_collect;
3067 const char *overflow_reason = NULL;
3069 MONO_GC_REQUESTED (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
3071 binary_protocol_collection_force (generation_to_collect);
3073 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
3075 mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
3077 TV_GETTIME (gc_start);
3079 sgen_stop_world (generation_to_collect);
3081 TV_GETTIME (gc_total_start);
3083 if (concurrent_collection_in_progress) {
3085 * We update the concurrent collection. If it finished, we're done. If
3086 * not, and we've been asked to do a nursery collection, we do that.
3088 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
3091 major_finish_concurrent_collection (wait_to_finish);
3092 oldest_generation_collected = GENERATION_OLD;
3094 sgen_workers_signal_start_nursery_collection_and_wait ();
3096 major_update_concurrent_collection ();
3097 if (generation_to_collect == GENERATION_NURSERY)
3098 collect_nursery (NULL, FALSE);
3100 sgen_workers_signal_finish_nursery_collection ();
3107 * If we've been asked to do a major collection, and the major collector wants to
3108 * run synchronously (to evacuate), we set the flag to do that.
3110 if (generation_to_collect == GENERATION_OLD &&
3111 allow_synchronous_major &&
3112 major_collector.want_synchronous_collection &&
3113 *major_collector.want_synchronous_collection) {
3114 wait_to_finish = TRUE;
3117 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3120 * There's no concurrent collection in progress. Collect the generation we're asked
3121 * to collect. If the major collector is concurrent and we're not forced to wait,
3122 * start a concurrent collection.
3124 // FIXME: extract overflow reason
3125 if (generation_to_collect == GENERATION_NURSERY) {
3126 if (collect_nursery (NULL, FALSE)) {
3127 overflow_generation_to_collect = GENERATION_OLD;
3128 overflow_reason = "Minor overflow";
3131 if (major_collector.is_concurrent && !wait_to_finish) {
3132 collect_nursery (NULL, FALSE);
3133 major_start_concurrent_collection (reason);
3134 // FIXME: set infos[0] properly
3138 if (major_do_collection (reason, wait_to_finish)) {
3139 overflow_generation_to_collect = GENERATION_NURSERY;
3140 overflow_reason = "Excessive pinning";
3144 TV_GETTIME (gc_end);
3146 memset (infos, 0, sizeof (infos));
3147 infos [0].generation = generation_to_collect;
3148 infos [0].reason = reason;
3149 infos [0].is_overflow = FALSE;
3150 infos [1].generation = -1;
3151 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
3153 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
3155 if (overflow_generation_to_collect != -1) {
3157 * We need to do an overflow collection, either because we ran out of memory
3158 * or the nursery is fully pinned.
3161 mono_profiler_gc_event (MONO_GC_EVENT_START, overflow_generation_to_collect);
3162 infos [1].generation = overflow_generation_to_collect;
3163 infos [1].reason = overflow_reason;
3164 infos [1].is_overflow = TRUE;
3165 infos [1].total_time = gc_end;
3167 if (overflow_generation_to_collect == GENERATION_NURSERY)
3168 collect_nursery (NULL, FALSE);
3170 major_do_collection (overflow_reason, wait_to_finish);
3172 TV_GETTIME (gc_end);
3173 infos [1].total_time = SGEN_TV_ELAPSED (infos [1].total_time, gc_end);
3175 /* keep events symmetric */
3176 mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
3178 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
3181 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
3183 /* this also sets the proper pointers for the next allocation */
3184 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
3185 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
3186 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
3187 sgen_dump_pin_queue ();
3192 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
3194 TV_GETTIME (gc_total_end);
3195 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
3197 sgen_restart_world (oldest_generation_collected, infos);
3199 mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
3203 * ######################################################################
3204 * ######## Memory allocation from the OS
3205 * ######################################################################
3206 * This section of code deals with getting memory from the OS and
3207 * allocating memory for GC-internal data structures.
3208 * Internal memory can be handled with a freelist for small objects.
3214 G_GNUC_UNUSED static void
3215 report_internal_mem_usage (void)
3217 printf ("Internal memory usage:\n");
3218 sgen_report_internal_mem_usage ();
3219 printf ("Pinned memory usage:\n");
3220 major_collector.report_pinned_memory_usage ();
3224 * ######################################################################
3225 * ######## Finalization support
3226 * ######################################################################
3229 static inline gboolean
3230 sgen_major_is_object_alive (void *object)
3234 /* Oldgen objects can be pinned and forwarded too */
3235 if (SGEN_OBJECT_IS_PINNED (object) || SGEN_OBJECT_IS_FORWARDED (object))
3239 * FIXME: major_collector.is_object_live() also calculates the
3240 * size. Avoid the double calculation.
3242 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size ((MonoObject*)object));
3243 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
3244 return sgen_los_object_is_pinned (object);
3246 return major_collector.is_object_live (object);
3250 * If the object has been forwarded it means it's still referenced from a root.
3251 * If it is pinned it's still alive as well.
3252 * A LOS object is only alive if we have pinned it.
3253 * Return TRUE if @obj is ready to be finalized.
3255 static inline gboolean
3256 sgen_is_object_alive (void *object)
3258 if (ptr_in_nursery (object))
3259 return sgen_nursery_is_object_alive (object);
3261 return sgen_major_is_object_alive (object);
3265 * This function returns true if @object is either alive or it belongs to the old gen
3266 * and we're currently doing a minor collection.
3269 sgen_is_object_alive_for_current_gen (char *object)
3271 if (ptr_in_nursery (object))
3272 return sgen_nursery_is_object_alive (object);
3274 if (current_collection_generation == GENERATION_NURSERY)
3277 return sgen_major_is_object_alive (object);
3281 * This function returns true if @object is either alive and belongs to the
3282 * current collection - major collections are full heap, so old gen objects
3283 * are never alive during a minor collection.
3286 sgen_is_object_alive_and_on_current_collection (char *object)
3288 if (ptr_in_nursery (object))
3289 return sgen_nursery_is_object_alive (object);
3291 if (current_collection_generation == GENERATION_NURSERY)
3294 return sgen_major_is_object_alive (object);
3299 sgen_gc_is_object_ready_for_finalization (void *object)
3301 return !sgen_is_object_alive (object);
3305 has_critical_finalizer (MonoObject *obj)
3309 if (!mono_defaults.critical_finalizer_object)
3312 class = ((MonoVTable*)LOAD_VTABLE (obj))->klass;
3314 return mono_class_has_parent_fast (class, mono_defaults.critical_finalizer_object);
3318 is_finalization_aware (MonoObject *obj)
3320 MonoVTable *vt = ((MonoVTable*)LOAD_VTABLE (obj));
3321 return (vt->gc_bits & SGEN_GC_BIT_FINALIZER_AWARE) == SGEN_GC_BIT_FINALIZER_AWARE;
3325 sgen_queue_finalization_entry (MonoObject *obj)
3327 FinalizeReadyEntry *entry = sgen_alloc_internal (INTERNAL_MEM_FINALIZE_READY_ENTRY);
3328 gboolean critical = has_critical_finalizer (obj);
3329 entry->object = obj;
3331 entry->next = critical_fin_list;
3332 critical_fin_list = entry;
3334 entry->next = fin_ready_list;
3335 fin_ready_list = entry;
3338 if (fin_callbacks.object_queued_for_finalization && is_finalization_aware (obj))
3339 fin_callbacks.object_queued_for_finalization (obj);
3341 #ifdef ENABLE_DTRACE
3342 if (G_UNLIKELY (MONO_GC_FINALIZE_ENQUEUE_ENABLED ())) {
3343 int gen = sgen_ptr_in_nursery (obj) ? GENERATION_NURSERY : GENERATION_OLD;
3344 MonoVTable *vt = (MonoVTable*)LOAD_VTABLE (obj);
3345 MONO_GC_FINALIZE_ENQUEUE ((mword)obj, sgen_safe_object_get_size (obj),
3346 vt->klass->name_space, vt->klass->name, gen, critical);
3352 sgen_object_is_live (void *obj)
3354 return sgen_is_object_alive_and_on_current_collection (obj);
3357 /* LOCKING: requires that the GC lock is held */
3359 null_ephemerons_for_domain (MonoDomain *domain)
3361 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3364 MonoObject *object = (MonoObject*)current->array;
3367 SGEN_ASSERT (0, object->vtable, "Can't have objects without vtables.");
3369 if (object && object->vtable->domain == domain) {
3370 EphemeronLinkNode *tmp = current;
3373 prev->next = current->next;
3375 ephemeron_list = current->next;
3377 current = current->next;
3378 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3381 current = current->next;
3386 /* LOCKING: requires that the GC lock is held */
3388 clear_unreachable_ephemerons (ScanCopyContext ctx)
3390 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
3391 GrayQueue *queue = ctx.queue;
3392 EphemeronLinkNode *current = ephemeron_list, *prev = NULL;
3394 Ephemeron *cur, *array_end;
3398 char *object = current->array;
3400 if (!sgen_is_object_alive_for_current_gen (object)) {
3401 EphemeronLinkNode *tmp = current;
3403 SGEN_LOG (5, "Dead Ephemeron array at %p", object);
3406 prev->next = current->next;
3408 ephemeron_list = current->next;
3410 current = current->next;
3411 sgen_free_internal (tmp, INTERNAL_MEM_EPHEMERON_LINK);
3416 copy_func ((void**)&object, queue);
3417 current->array = object;
3419 SGEN_LOG (5, "Clearing unreachable entries for ephemeron array at %p", object);
3421 array = (MonoArray*)object;
3422 cur = mono_array_addr (array, Ephemeron, 0);
3423 array_end = cur + mono_array_length_fast (array);
3424 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3426 for (; cur < array_end; ++cur) {
3427 char *key = (char*)cur->key;
3429 if (!key || key == tombstone)
3432 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3433 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3434 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3436 if (!sgen_is_object_alive_for_current_gen (key)) {
3437 cur->key = tombstone;
3443 current = current->next;
3448 LOCKING: requires that the GC lock is held
3450 Limitations: We scan all ephemerons on every collection since the current design doesn't allow for a simple nursery/mature split.
3453 mark_ephemerons_in_range (ScanCopyContext ctx)
3455 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
3456 GrayQueue *queue = ctx.queue;
3457 int nothing_marked = 1;
3458 EphemeronLinkNode *current = ephemeron_list;
3460 Ephemeron *cur, *array_end;
3463 for (current = ephemeron_list; current; current = current->next) {
3464 char *object = current->array;
3465 SGEN_LOG (5, "Ephemeron array at %p", object);
3467 /*It has to be alive*/
3468 if (!sgen_is_object_alive_for_current_gen (object)) {
3469 SGEN_LOG (5, "\tnot reachable");
3473 copy_func ((void**)&object, queue);
3475 array = (MonoArray*)object;
3476 cur = mono_array_addr (array, Ephemeron, 0);
3477 array_end = cur + mono_array_length_fast (array);
3478 tombstone = (char*)((MonoVTable*)LOAD_VTABLE (object))->domain->ephemeron_tombstone;
3480 for (; cur < array_end; ++cur) {
3481 char *key = cur->key;
3483 if (!key || key == tombstone)
3486 SGEN_LOG (5, "[%td] key %p (%s) value %p (%s)", cur - mono_array_addr (array, Ephemeron, 0),
3487 key, sgen_is_object_alive_for_current_gen (key) ? "reachable" : "unreachable",
3488 cur->value, cur->value && sgen_is_object_alive_for_current_gen (cur->value) ? "reachable" : "unreachable");
3490 if (sgen_is_object_alive_for_current_gen (key)) {
3491 char *value = cur->value;
3493 copy_func ((void**)&cur->key, queue);
3495 if (!sgen_is_object_alive_for_current_gen (value))
3497 copy_func ((void**)&cur->value, queue);
3503 SGEN_LOG (5, "Ephemeron run finished. Is it done %d", nothing_marked);
3504 return nothing_marked;
3508 mono_gc_invoke_finalizers (void)
3510 FinalizeReadyEntry *entry = NULL;
3511 gboolean entry_is_critical = FALSE;
3514 /* FIXME: batch to reduce lock contention */
3515 while (fin_ready_list || critical_fin_list) {
3519 FinalizeReadyEntry **list = entry_is_critical ? &critical_fin_list : &fin_ready_list;
3521 /* We have finalized entry in the last
3522 interation, now we need to remove it from
3525 *list = entry->next;
3527 FinalizeReadyEntry *e = *list;
3528 while (e->next != entry)
3530 e->next = entry->next;
3532 sgen_free_internal (entry, INTERNAL_MEM_FINALIZE_READY_ENTRY);
3536 /* Now look for the first non-null entry. */
3537 for (entry = fin_ready_list; entry && !entry->object; entry = entry->next)
3540 entry_is_critical = FALSE;
3542 entry_is_critical = TRUE;
3543 for (entry = critical_fin_list; entry && !entry->object; entry = entry->next)
3548 g_assert (entry->object);
3549 num_ready_finalizers--;
3550 obj = entry->object;
3551 entry->object = NULL;
3552 SGEN_LOG (7, "Finalizing object %p (%s)", obj, safe_name (obj));
3560 g_assert (entry->object == NULL);
3562 /* the object is on the stack so it is pinned */
3563 /*g_print ("Calling finalizer for object: %p (%s)\n", entry->object, safe_name (entry->object));*/
3564 mono_gc_run_finalize (obj, NULL);
3571 mono_gc_pending_finalizers (void)
3573 return fin_ready_list || critical_fin_list;
3577 * ######################################################################
3578 * ######## registered roots support
3579 * ######################################################################
3583 * We do not coalesce roots.
3586 mono_gc_register_root_inner (char *start, size_t size, void *descr, int root_type)
3588 RootRecord new_root;
3591 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
3592 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
3593 /* we allow changing the size and the descriptor (for thread statics etc) */
3595 size_t old_size = root->end_root - start;
3596 root->end_root = start + size;
3597 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
3598 ((root->root_desc == 0) && (descr == NULL)));
3599 root->root_desc = (mword)descr;
3601 roots_size -= old_size;
3607 new_root.end_root = start + size;
3608 new_root.root_desc = (mword)descr;
3610 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
3613 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);
3620 mono_gc_register_root (char *start, size_t size, void *descr)
3622 return mono_gc_register_root_inner (start, size, descr, descr ? ROOT_TYPE_NORMAL : ROOT_TYPE_PINNED);
3626 mono_gc_register_root_wbarrier (char *start, size_t size, void *descr)
3628 return mono_gc_register_root_inner (start, size, descr, ROOT_TYPE_WBARRIER);
3632 mono_gc_deregister_root (char* addr)
3638 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
3639 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
3640 roots_size -= (root.end_root - addr);
3646 * ######################################################################
3647 * ######## Thread handling (stop/start code)
3648 * ######################################################################
3651 unsigned int sgen_global_stop_count = 0;
3654 sgen_get_current_collection_generation (void)
3656 return current_collection_generation;
3660 mono_gc_set_gc_callbacks (MonoGCCallbacks *callbacks)
3662 gc_callbacks = *callbacks;
3666 mono_gc_get_gc_callbacks ()
3668 return &gc_callbacks;
3671 /* Variables holding start/end nursery so it won't have to be passed at every call */
3672 static void *scan_area_arg_start, *scan_area_arg_end;
3675 mono_gc_conservatively_scan_area (void *start, void *end)
3677 conservatively_pin_objects_from (start, end, scan_area_arg_start, scan_area_arg_end, PIN_TYPE_STACK);
3681 mono_gc_scan_object (void *obj, void *gc_data)
3683 ScanCopyContext *ctx = gc_data;
3684 ctx->ops->copy_or_mark_object (&obj, ctx->queue);
3689 * Mark from thread stacks and registers.
3692 scan_thread_data (void *start_nursery, void *end_nursery, gboolean precise, ScanCopyContext ctx)
3694 SgenThreadInfo *info;
3696 scan_area_arg_start = start_nursery;
3697 scan_area_arg_end = end_nursery;
3699 FOREACH_THREAD (info) {
3701 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);
3704 if (info->gc_disabled) {
3705 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);
3708 if (!mono_thread_info_is_live (info)) {
3709 SGEN_LOG (3, "Skipping non-running thread %p, range: %p-%p, size: %td (state %x)", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, info->info.thread_state);
3712 g_assert (info->suspend_done);
3713 SGEN_LOG (3, "Scanning thread %p, range: %p-%p, size: %td, pinned=%zd", info, info->stack_start, info->stack_end, (char*)info->stack_end - (char*)info->stack_start, sgen_get_pinned_count ());
3714 if (gc_callbacks.thread_mark_func && !conservative_stack_mark) {
3715 gc_callbacks.thread_mark_func (info->runtime_data, info->stack_start, info->stack_end, precise, &ctx);
3716 } else if (!precise) {
3717 if (!conservative_stack_mark) {
3718 fprintf (stderr, "Precise stack mark not supported - disabling.\n");
3719 conservative_stack_mark = TRUE;
3721 conservatively_pin_objects_from (info->stack_start, info->stack_end, start_nursery, end_nursery, PIN_TYPE_STACK);
3726 conservatively_pin_objects_from ((void**)&info->ctx, (void**)&info->ctx + ARCH_NUM_REGS,
3727 start_nursery, end_nursery, PIN_TYPE_STACK);
3729 conservatively_pin_objects_from ((void**)&info->regs, (void**)&info->regs + ARCH_NUM_REGS,
3730 start_nursery, end_nursery, PIN_TYPE_STACK);
3733 } END_FOREACH_THREAD
3737 ptr_on_stack (void *ptr)
3739 gpointer stack_start = &stack_start;
3740 SgenThreadInfo *info = mono_thread_info_current ();
3742 if (ptr >= stack_start && ptr < (gpointer)info->stack_end)
3748 sgen_thread_register (SgenThreadInfo* info, void *addr)
3751 guint8 *staddr = NULL;
3753 #ifndef HAVE_KW_THREAD
3754 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
3756 g_assert (!mono_native_tls_get_value (thread_info_key));
3757 mono_native_tls_set_value (thread_info_key, info);
3759 sgen_thread_info = info;
3762 #ifdef SGEN_POSIX_STW
3763 info->stop_count = -1;
3767 info->stack_start = NULL;
3768 info->stopped_ip = NULL;
3769 info->stopped_domain = NULL;
3771 memset (&info->ctx, 0, sizeof (MonoContext));
3773 memset (&info->regs, 0, sizeof (info->regs));
3776 sgen_init_tlab_info (info);
3778 binary_protocol_thread_register ((gpointer)mono_thread_info_get_tid (info));
3780 /* On win32, stack_start_limit should be 0, since the stack can grow dynamically */
3781 mono_thread_info_get_stack_bounds (&staddr, &stsize);
3784 info->stack_start_limit = staddr;
3786 info->stack_end = staddr + stsize;
3788 gsize stack_bottom = (gsize)addr;
3789 stack_bottom += 4095;
3790 stack_bottom &= ~4095;
3791 info->stack_end = (char*)stack_bottom;
3794 #ifdef HAVE_KW_THREAD
3795 stack_end = info->stack_end;
3798 SGEN_LOG (3, "registered thread %p (%p) stack end %p", info, (gpointer)mono_thread_info_get_tid (info), info->stack_end);
3800 if (gc_callbacks.thread_attach_func)
3801 info->runtime_data = gc_callbacks.thread_attach_func ();
3806 sgen_thread_detach (SgenThreadInfo *p)
3808 /* If a delegate is passed to native code and invoked on a thread we dont
3809 * know about, the jit will register it with mono_jit_thread_attach, but
3810 * we have no way of knowing when that thread goes away. SGen has a TSD
3811 * so we assume that if the domain is still registered, we can detach
3814 if (mono_domain_get ())
3815 mono_thread_detach_internal (mono_thread_internal_current ());
3819 sgen_thread_unregister (SgenThreadInfo *p)
3821 MonoNativeThreadId tid;
3823 tid = mono_thread_info_get_tid (p);
3824 binary_protocol_thread_unregister ((gpointer)tid);
3825 SGEN_LOG (3, "unregister thread %p (%p)", p, (gpointer)tid);
3827 #ifndef HAVE_KW_THREAD
3828 mono_native_tls_set_value (thread_info_key, NULL);
3830 sgen_thread_info = NULL;
3833 if (p->info.runtime_thread)
3834 mono_threads_add_joinable_thread ((gpointer)tid);
3836 if (gc_callbacks.thread_detach_func) {
3837 gc_callbacks.thread_detach_func (p->runtime_data);
3838 p->runtime_data = NULL;
3844 sgen_thread_attach (SgenThreadInfo *info)
3847 /*this is odd, can we get attached before the gc is inited?*/
3851 if (gc_callbacks.thread_attach_func && !info->runtime_data)
3852 info->runtime_data = gc_callbacks.thread_attach_func ();
3855 mono_gc_register_thread (void *baseptr)
3857 return mono_thread_info_attach (baseptr) != NULL;
3861 * mono_gc_set_stack_end:
3863 * Set the end of the current threads stack to STACK_END. The stack space between
3864 * STACK_END and the real end of the threads stack will not be scanned during collections.
3867 mono_gc_set_stack_end (void *stack_end)
3869 SgenThreadInfo *info;
3872 info = mono_thread_info_current ();
3874 g_assert (stack_end < info->stack_end);
3875 info->stack_end = stack_end;
3880 #if USE_PTHREAD_INTERCEPT
3884 mono_gc_pthread_create (pthread_t *new_thread, const pthread_attr_t *attr, void *(*start_routine)(void *), void *arg)
3886 return pthread_create (new_thread, attr, start_routine, arg);
3890 mono_gc_pthread_join (pthread_t thread, void **retval)
3892 return pthread_join (thread, retval);
3896 mono_gc_pthread_detach (pthread_t thread)
3898 return pthread_detach (thread);
3902 mono_gc_pthread_exit (void *retval)
3904 mono_thread_info_detach ();
3905 pthread_exit (retval);
3906 g_assert_not_reached ();
3909 #endif /* USE_PTHREAD_INTERCEPT */
3912 * ######################################################################
3913 * ######## Write barriers
3914 * ######################################################################
3918 * Note: the write barriers first do the needed GC work and then do the actual store:
3919 * this way the value is visible to the conservative GC scan after the write barrier
3920 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
3921 * the conservative scan, otherwise by the remembered set scan.
3924 mono_gc_wbarrier_set_field (MonoObject *obj, gpointer field_ptr, MonoObject* value)
3926 HEAVY_STAT (++stat_wbarrier_set_field);
3927 if (ptr_in_nursery (field_ptr)) {
3928 *(void**)field_ptr = value;
3931 SGEN_LOG (8, "Adding remset at %p", field_ptr);
3933 binary_protocol_wbarrier (field_ptr, value, value->vtable);
3935 remset.wbarrier_set_field (obj, field_ptr, value);
3939 mono_gc_wbarrier_set_arrayref (MonoArray *arr, gpointer slot_ptr, MonoObject* value)
3941 HEAVY_STAT (++stat_wbarrier_set_arrayref);
3942 if (ptr_in_nursery (slot_ptr)) {
3943 *(void**)slot_ptr = value;
3946 SGEN_LOG (8, "Adding remset at %p", slot_ptr);
3948 binary_protocol_wbarrier (slot_ptr, value, value->vtable);
3950 remset.wbarrier_set_arrayref (arr, slot_ptr, value);
3954 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
3956 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
3957 /*This check can be done without taking a lock since dest_ptr array is pinned*/
3958 if (ptr_in_nursery (dest_ptr) || count <= 0) {
3959 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
3963 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
3964 if (binary_protocol_is_heavy_enabled ()) {
3966 for (i = 0; i < count; ++i) {
3967 gpointer dest = (gpointer*)dest_ptr + i;
3968 gpointer obj = *((gpointer*)src_ptr + i);
3970 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
3975 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
3979 mono_gc_wbarrier_generic_nostore (gpointer ptr)
3983 HEAVY_STAT (++stat_wbarrier_generic_store);
3985 #ifdef XDOMAIN_CHECKS_IN_WBARRIER
3986 /* FIXME: ptr_in_heap must be called with the GC lock held */
3987 if (xdomain_checks && *(MonoObject**)ptr && ptr_in_heap (ptr)) {
3988 char *start = sgen_find_object_for_ptr (ptr);
3989 MonoObject *value = *(MonoObject**)ptr;
3993 MonoObject *obj = (MonoObject*)start;
3994 if (obj->vtable->domain != value->vtable->domain)
3995 g_assert (is_xdomain_ref_allowed (ptr, start, obj->vtable->domain));
4001 obj = *(gpointer*)ptr;
4003 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
4005 if (ptr_in_nursery (ptr) || ptr_on_stack (ptr)) {
4006 SGEN_LOG (8, "Skipping remset at %p", ptr);
4011 * We need to record old->old pointer locations for the
4012 * concurrent collector.
4014 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
4015 SGEN_LOG (8, "Skipping remset at %p", ptr);
4019 SGEN_LOG (8, "Adding remset at %p", ptr);
4021 remset.wbarrier_generic_nostore (ptr);
4025 mono_gc_wbarrier_generic_store (gpointer ptr, MonoObject* value)
4027 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4028 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
4029 if (ptr_in_nursery (value))
4030 mono_gc_wbarrier_generic_nostore (ptr);
4031 sgen_dummy_use (value);
4034 /* Same as mono_gc_wbarrier_generic_store () but performs the store
4035 * as an atomic operation with release semantics.
4038 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, MonoObject *value)
4040 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
4042 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? safe_name (value) : "null");
4044 InterlockedWritePointer (ptr, value);
4046 if (ptr_in_nursery (value))
4047 mono_gc_wbarrier_generic_nostore (ptr);
4049 sgen_dummy_use (value);
4052 void mono_gc_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
4054 mword *dest = _dest;
4059 mono_gc_wbarrier_generic_store (dest, (MonoObject*)*src);
4061 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
4064 size -= SIZEOF_VOID_P;
4069 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4071 #define HANDLE_PTR(ptr,obj) do { \
4072 gpointer o = *(gpointer*)(ptr); \
4074 gpointer d = ((char*)dest) + ((char*)(ptr) - (char*)(obj)); \
4075 binary_protocol_wbarrier (d, o, (gpointer) LOAD_VTABLE (o)); \
4080 scan_object_for_binary_protocol_copy_wbarrier (gpointer dest, char *start, mword desc)
4082 #define SCAN_OBJECT_NOVTABLE
4083 #include "sgen-scan-object.h"
4088 mono_gc_wbarrier_value_copy (gpointer dest, gpointer src, int count, MonoClass *klass)
4090 HEAVY_STAT (++stat_wbarrier_value_copy);
4091 g_assert (klass->valuetype);
4093 SGEN_LOG (8, "Adding value remset at %p, count %d, descr %p for class %s (%p)", dest, count, klass->gc_descr, klass->name, klass);
4095 if (ptr_in_nursery (dest) || ptr_on_stack (dest) || !SGEN_CLASS_HAS_REFERENCES (klass)) {
4096 size_t element_size = mono_class_value_size (klass, NULL);
4097 size_t size = count * element_size;
4098 mono_gc_memmove_atomic (dest, src, size);
4102 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4103 if (binary_protocol_is_heavy_enabled ()) {
4104 size_t element_size = mono_class_value_size (klass, NULL);
4106 for (i = 0; i < count; ++i) {
4107 scan_object_for_binary_protocol_copy_wbarrier ((char*)dest + i * element_size,
4108 (char*)src + i * element_size - sizeof (MonoObject),
4109 (mword) klass->gc_descr);
4114 remset.wbarrier_value_copy (dest, src, count, klass);
4118 * mono_gc_wbarrier_object_copy:
4120 * Write barrier to call when obj is the result of a clone or copy of an object.
4123 mono_gc_wbarrier_object_copy (MonoObject* obj, MonoObject *src)
4127 HEAVY_STAT (++stat_wbarrier_object_copy);
4129 if (ptr_in_nursery (obj) || ptr_on_stack (obj)) {
4130 size = mono_object_class (obj)->instance_size;
4131 mono_gc_memmove_aligned ((char*)obj + sizeof (MonoObject), (char*)src + sizeof (MonoObject),
4132 size - sizeof (MonoObject));
4136 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
4137 if (binary_protocol_is_heavy_enabled ())
4138 scan_object_for_binary_protocol_copy_wbarrier (obj, (char*)src, (mword) src->vtable->gc_descr);
4141 remset.wbarrier_object_copy (obj, src);
4146 * ######################################################################
4147 * ######## Other mono public interface functions.
4148 * ######################################################################
4151 #define REFS_SIZE 128
4154 MonoGCReferences callback;
4158 MonoObject *refs [REFS_SIZE];
4159 uintptr_t offsets [REFS_SIZE];
4163 #define HANDLE_PTR(ptr,obj) do { \
4165 if (hwi->count == REFS_SIZE) { \
4166 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data); \
4170 hwi->offsets [hwi->count] = (char*)(ptr)-(char*)start; \
4171 hwi->refs [hwi->count++] = *(ptr); \
4176 collect_references (HeapWalkInfo *hwi, char *start, size_t size)
4178 mword desc = sgen_obj_get_descriptor (start);
4180 #include "sgen-scan-object.h"
4184 walk_references (char *start, size_t size, void *data)
4186 HeapWalkInfo *hwi = data;
4189 collect_references (hwi, start, size);
4190 if (hwi->count || !hwi->called)
4191 hwi->callback ((MonoObject*)start, mono_object_class (start), hwi->called? 0: size, hwi->count, hwi->refs, hwi->offsets, hwi->data);
4195 * mono_gc_walk_heap:
4196 * @flags: flags for future use
4197 * @callback: a function pointer called for each object in the heap
4198 * @data: a user data pointer that is passed to callback
4200 * This function can be used to iterate over all the live objects in the heap:
4201 * for each object, @callback is invoked, providing info about the object's
4202 * location in memory, its class, its size and the objects it references.
4203 * For each referenced object it's offset from the object address is
4204 * reported in the offsets array.
4205 * The object references may be buffered, so the callback may be invoked
4206 * multiple times for the same object: in all but the first call, the size
4207 * argument will be zero.
4208 * Note that this function can be only called in the #MONO_GC_EVENT_PRE_START_WORLD
4209 * profiler event handler.
4211 * Returns: a non-zero value if the GC doesn't support heap walking
4214 mono_gc_walk_heap (int flags, MonoGCReferences callback, void *data)
4219 hwi.callback = callback;
4222 sgen_clear_nursery_fragments ();
4223 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data, walk_references, &hwi, FALSE);
4225 major_collector.iterate_objects (ITERATE_OBJECTS_SWEEP_ALL, walk_references, &hwi);
4226 sgen_los_iterate_objects (walk_references, &hwi);
4232 mono_gc_collect (int generation)
4237 sgen_perform_collection (0, generation, "user request", TRUE);
4242 mono_gc_max_generation (void)
4248 mono_gc_collection_count (int generation)
4250 if (generation == 0)
4251 return gc_stats.minor_gc_count;
4252 return gc_stats.major_gc_count;
4256 mono_gc_get_used_size (void)
4260 tot = los_memory_usage;
4261 tot += nursery_section->next_data - nursery_section->data;
4262 tot += major_collector.get_used_size ();
4263 /* FIXME: account for pinned objects */
4269 mono_gc_get_los_limit (void)
4271 return MAX_SMALL_OBJ_SIZE;
4275 mono_gc_set_string_length (MonoString *str, gint32 new_length)
4277 mono_unichar2 *new_end = str->chars + new_length;
4279 /* zero the discarded string. This null-delimits the string and allows
4280 * the space to be reclaimed by SGen. */
4282 if (nursery_canaries_enabled () && sgen_ptr_in_nursery (str)) {
4283 CHECK_CANARY_FOR_OBJECT (str);
4284 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2) + CANARY_SIZE);
4285 memcpy (new_end + 1 , CANARY_STRING, CANARY_SIZE);
4287 memset (new_end, 0, (str->length - new_length + 1) * sizeof (mono_unichar2));
4290 str->length = new_length;
4294 mono_gc_user_markers_supported (void)
4300 mono_object_is_alive (MonoObject* o)
4306 mono_gc_get_generation (MonoObject *obj)
4308 if (ptr_in_nursery (obj))
4314 mono_gc_enable_events (void)
4319 mono_gc_weak_link_add (void **link_addr, MonoObject *obj, gboolean track)
4321 sgen_register_disappearing_link (obj, link_addr, track, FALSE);
4325 mono_gc_weak_link_remove (void **link_addr, gboolean track)
4327 sgen_register_disappearing_link (NULL, link_addr, track, FALSE);
4331 mono_gc_weak_link_get (void **link_addr)
4333 void * volatile *link_addr_volatile;
4337 link_addr_volatile = link_addr;
4338 ptr = (void*)*link_addr_volatile;
4340 * At this point we have a hidden pointer. If the GC runs
4341 * here, it will not recognize the hidden pointer as a
4342 * reference, and if the object behind it is not referenced
4343 * elsewhere, it will be freed. Once the world is restarted
4344 * we reveal the pointer, giving us a pointer to a freed
4345 * object. To make sure we don't return it, we load the
4346 * hidden pointer again. If it's still the same, we can be
4347 * sure the object reference is valid.
4350 obj = (MonoObject*) REVEAL_POINTER (ptr);
4354 mono_memory_barrier ();
4357 * During the second bridge processing step the world is
4358 * running again. That step processes all weak links once
4359 * more to null those that refer to dead objects. Before that
4360 * is completed, those links must not be followed, so we
4361 * conservatively wait for bridge processing when any weak
4362 * link is dereferenced.
4364 if (G_UNLIKELY (bridge_processing_in_progress))
4365 mono_gc_wait_for_bridge_processing ();
4367 if ((void*)*link_addr_volatile != ptr)
4374 mono_gc_ephemeron_array_add (MonoObject *obj)
4376 EphemeronLinkNode *node;
4380 node = sgen_alloc_internal (INTERNAL_MEM_EPHEMERON_LINK);
4385 node->array = (char*)obj;
4386 node->next = ephemeron_list;
4387 ephemeron_list = node;
4389 SGEN_LOG (5, "Registered ephemeron array %p", obj);
4396 mono_gc_set_allow_synchronous_major (gboolean flag)
4398 if (!major_collector.is_concurrent)
4401 allow_synchronous_major = flag;
4406 mono_gc_invoke_with_gc_lock (MonoGCLockedCallbackFunc func, void *data)
4410 result = func (data);
4411 UNLOCK_INTERRUPTION;
4416 mono_gc_is_gc_thread (void)
4420 result = mono_thread_info_current () != NULL;
4426 is_critical_method (MonoMethod *method)
4428 return mono_runtime_is_critical_method (method) || sgen_is_critical_method (method);
4432 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
4436 va_start (ap, description_format);
4438 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
4439 vfprintf (stderr, description_format, ap);
4441 fprintf (stderr, " - %s", fallback);
4442 fprintf (stderr, "\n");
4448 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
4451 double val = strtod (opt, &endptr);
4452 if (endptr == opt) {
4453 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
4456 else if (val < min || val > max) {
4457 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
4465 thread_in_critical_region (SgenThreadInfo *info)
4467 return info->in_critical_region;
4471 mono_gc_base_init (void)
4473 MonoThreadInfoCallbacks cb;
4476 char *major_collector_opt = NULL;
4477 char *minor_collector_opt = NULL;
4478 size_t max_heap = 0;
4479 size_t soft_limit = 0;
4482 gboolean debug_print_allowance = FALSE;
4483 double allowance_ratio = 0, save_target = 0;
4484 gboolean cement_enabled = TRUE;
4486 mono_counters_init ();
4489 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
4492 /* already inited */
4495 /* being inited by another thread */
4499 /* we will init it */
4502 g_assert_not_reached ();
4504 } while (result != 0);
4506 SGEN_TV_GETTIME (sgen_init_timestamp);
4508 LOCK_INIT (gc_mutex);
4510 pagesize = mono_pagesize ();
4511 gc_debug_file = stderr;
4513 cb.thread_register = sgen_thread_register;
4514 cb.thread_detach = sgen_thread_detach;
4515 cb.thread_unregister = sgen_thread_unregister;
4516 cb.thread_attach = sgen_thread_attach;
4517 cb.mono_method_is_critical = (gpointer)is_critical_method;
4518 cb.mono_thread_in_critical_region = thread_in_critical_region;
4520 cb.thread_exit = mono_gc_pthread_exit;
4521 cb.mono_gc_pthread_create = (gpointer)mono_gc_pthread_create;
4524 mono_threads_init (&cb, sizeof (SgenThreadInfo));
4526 LOCK_INIT (sgen_interruption_mutex);
4528 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
4529 opts = g_strsplit (env, ",", -1);
4530 for (ptr = opts; *ptr; ++ptr) {
4532 if (g_str_has_prefix (opt, "major=")) {
4533 opt = strchr (opt, '=') + 1;
4534 major_collector_opt = g_strdup (opt);
4535 } else if (g_str_has_prefix (opt, "minor=")) {
4536 opt = strchr (opt, '=') + 1;
4537 minor_collector_opt = g_strdup (opt);
4545 sgen_init_internal_allocator ();
4546 sgen_init_nursery_allocator ();
4547 sgen_init_fin_weak_hash ();
4549 sgen_init_hash_table ();
4550 sgen_init_descriptors ();
4551 sgen_init_gray_queues ();
4553 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
4554 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_FINALIZE_READY_ENTRY, sizeof (FinalizeReadyEntry));
4555 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
4556 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_EPHEMERON_LINK, sizeof (EphemeronLinkNode));
4558 #ifndef HAVE_KW_THREAD
4559 mono_native_tls_alloc (&thread_info_key, NULL);
4560 #if defined(__APPLE__) || defined (HOST_WIN32)
4562 * CEE_MONO_TLS requires the tls offset, not the key, so the code below only works on darwin,
4563 * where the two are the same.
4565 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, thread_info_key);
4569 int tls_offset = -1;
4570 MONO_THREAD_VAR_OFFSET (sgen_thread_info, tls_offset);
4571 mono_tls_key_set_offset (TLS_KEY_SGEN_THREAD_INFO, tls_offset);
4576 * This needs to happen before any internal allocations because
4577 * it inits the small id which is required for hazard pointer
4582 mono_thread_info_attach (&dummy);
4584 if (!minor_collector_opt) {
4585 sgen_simple_nursery_init (&sgen_minor_collector);
4587 if (!strcmp (minor_collector_opt, "simple")) {
4589 sgen_simple_nursery_init (&sgen_minor_collector);
4590 } else if (!strcmp (minor_collector_opt, "split")) {
4591 sgen_split_nursery_init (&sgen_minor_collector);
4593 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
4594 goto use_simple_nursery;
4598 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
4599 use_marksweep_major:
4600 sgen_marksweep_init (&major_collector);
4601 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
4602 sgen_marksweep_conc_init (&major_collector);
4604 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
4605 goto use_marksweep_major;
4608 ///* Keep this the default for now */
4609 /* Precise marking is broken on all supported targets. Disable until fixed. */
4610 conservative_stack_mark = TRUE;
4612 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
4614 if (major_collector.is_concurrent)
4615 cement_enabled = FALSE;
4618 gboolean usage_printed = FALSE;
4620 for (ptr = opts; *ptr; ++ptr) {
4622 if (!strcmp (opt, ""))
4624 if (g_str_has_prefix (opt, "major="))
4626 if (g_str_has_prefix (opt, "minor="))
4628 if (g_str_has_prefix (opt, "max-heap-size=")) {
4629 size_t max_heap_candidate = 0;
4630 opt = strchr (opt, '=') + 1;
4631 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
4632 max_heap = (max_heap_candidate + mono_pagesize () - 1) & ~(size_t)(mono_pagesize () - 1);
4633 if (max_heap != max_heap_candidate)
4634 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", mono_pagesize ());
4636 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
4640 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
4641 opt = strchr (opt, '=') + 1;
4642 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
4643 if (soft_limit <= 0) {
4644 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
4648 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
4652 if (g_str_has_prefix (opt, "stack-mark=")) {
4653 opt = strchr (opt, '=') + 1;
4654 if (!strcmp (opt, "precise")) {
4655 conservative_stack_mark = FALSE;
4656 } else if (!strcmp (opt, "conservative")) {
4657 conservative_stack_mark = TRUE;
4659 sgen_env_var_error (MONO_GC_PARAMS_NAME, conservative_stack_mark ? "Using `conservative`." : "Using `precise`.",
4660 "Invalid value `%s` for `stack-mark` option, possible values are: `precise`, `conservative`.", opt);
4664 if (g_str_has_prefix (opt, "bridge-implementation=")) {
4665 opt = strchr (opt, '=') + 1;
4666 sgen_set_bridge_implementation (opt);
4669 if (g_str_has_prefix (opt, "toggleref-test")) {
4670 sgen_register_test_toggleref_callback ();
4675 if (g_str_has_prefix (opt, "nursery-size=")) {
4677 opt = strchr (opt, '=') + 1;
4678 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
4679 if ((val & (val - 1))) {
4680 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
4684 if (val < SGEN_MAX_NURSERY_WASTE) {
4685 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
4686 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
4690 sgen_nursery_size = val;
4691 sgen_nursery_bits = 0;
4692 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
4695 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
4701 if (g_str_has_prefix (opt, "save-target-ratio=")) {
4703 opt = strchr (opt, '=') + 1;
4704 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
4705 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
4710 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
4712 opt = strchr (opt, '=') + 1;
4713 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
4714 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
4715 allowance_ratio = val;
4719 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
4720 if (!major_collector.is_concurrent) {
4721 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
4725 opt = strchr (opt, '=') + 1;
4727 if (!strcmp (opt, "yes")) {
4728 allow_synchronous_major = TRUE;
4729 } else if (!strcmp (opt, "no")) {
4730 allow_synchronous_major = FALSE;
4732 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
4737 if (!strcmp (opt, "cementing")) {
4738 cement_enabled = TRUE;
4741 if (!strcmp (opt, "no-cementing")) {
4742 cement_enabled = FALSE;
4746 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
4749 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
4752 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4757 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
4758 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4759 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
4760 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
4761 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
4762 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
4763 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
4764 fprintf (stderr, " stack-mark=MARK-METHOD (where MARK-METHOD is 'precise' or 'conservative')\n");
4765 fprintf (stderr, " [no-]cementing\n");
4766 if (major_collector.is_concurrent)
4767 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
4768 if (major_collector.print_gc_param_usage)
4769 major_collector.print_gc_param_usage ();
4770 if (sgen_minor_collector.print_gc_param_usage)
4771 sgen_minor_collector.print_gc_param_usage ();
4772 fprintf (stderr, " Experimental options:\n");
4773 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
4774 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);
4775 fprintf (stderr, "\n");
4777 usage_printed = TRUE;
4782 if (major_collector_opt)
4783 g_free (major_collector_opt);
4785 if (minor_collector_opt)
4786 g_free (minor_collector_opt);
4790 if (major_collector.is_concurrent && cement_enabled) {
4791 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported on concurrent major collectors.");
4792 cement_enabled = FALSE;
4795 sgen_cement_init (cement_enabled);
4797 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
4798 gboolean usage_printed = FALSE;
4800 opts = g_strsplit (env, ",", -1);
4801 for (ptr = opts; ptr && *ptr; ptr ++) {
4803 if (!strcmp (opt, ""))
4805 if (opt [0] >= '0' && opt [0] <= '9') {
4806 gc_debug_level = atoi (opt);
4811 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
4812 gc_debug_file = fopen (rf, "wb");
4814 gc_debug_file = stderr;
4817 } else if (!strcmp (opt, "print-allowance")) {
4818 debug_print_allowance = TRUE;
4819 } else if (!strcmp (opt, "print-pinning")) {
4820 sgen_pin_stats_enable ();
4821 } else if (!strcmp (opt, "verify-before-allocs")) {
4822 verify_before_allocs = 1;
4823 has_per_allocation_action = TRUE;
4824 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
4825 char *arg = strchr (opt, '=') + 1;
4826 verify_before_allocs = atoi (arg);
4827 has_per_allocation_action = TRUE;
4828 } else if (!strcmp (opt, "collect-before-allocs")) {
4829 collect_before_allocs = 1;
4830 has_per_allocation_action = TRUE;
4831 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
4832 char *arg = strchr (opt, '=') + 1;
4833 has_per_allocation_action = TRUE;
4834 collect_before_allocs = atoi (arg);
4835 } else if (!strcmp (opt, "verify-before-collections")) {
4836 whole_heap_check_before_collection = TRUE;
4837 } else if (!strcmp (opt, "check-at-minor-collections")) {
4838 consistency_check_at_minor_collection = TRUE;
4839 nursery_clear_policy = CLEAR_AT_GC;
4840 } else if (!strcmp (opt, "mod-union-consistency-check")) {
4841 if (!major_collector.is_concurrent) {
4842 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
4845 mod_union_consistency_check = TRUE;
4846 } else if (!strcmp (opt, "check-mark-bits")) {
4847 check_mark_bits_after_major_collection = TRUE;
4848 } else if (!strcmp (opt, "check-nursery-pinned")) {
4849 check_nursery_objects_pinned = TRUE;
4850 } else if (!strcmp (opt, "xdomain-checks")) {
4851 xdomain_checks = TRUE;
4852 } else if (!strcmp (opt, "clear-at-gc")) {
4853 nursery_clear_policy = CLEAR_AT_GC;
4854 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
4855 nursery_clear_policy = CLEAR_AT_GC;
4856 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
4857 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
4858 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
4859 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
4860 } else if (!strcmp (opt, "check-scan-starts")) {
4861 do_scan_starts_check = TRUE;
4862 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
4863 do_verify_nursery = TRUE;
4864 } else if (!strcmp (opt, "check-concurrent")) {
4865 if (!major_collector.is_concurrent) {
4866 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
4869 do_concurrent_checks = TRUE;
4870 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
4871 do_dump_nursery_content = TRUE;
4872 } else if (!strcmp (opt, "no-managed-allocator")) {
4873 sgen_set_use_managed_allocator (FALSE);
4874 } else if (!strcmp (opt, "disable-minor")) {
4875 disable_minor_collections = TRUE;
4876 } else if (!strcmp (opt, "disable-major")) {
4877 disable_major_collections = TRUE;
4878 } else if (g_str_has_prefix (opt, "heap-dump=")) {
4879 char *filename = strchr (opt, '=') + 1;
4880 nursery_clear_policy = CLEAR_AT_GC;
4881 heap_dump_file = fopen (filename, "w");
4882 if (heap_dump_file) {
4883 fprintf (heap_dump_file, "<sgen-dump>\n");
4884 sgen_pin_stats_enable ();
4886 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
4887 char *filename = strchr (opt, '=') + 1;
4888 char *colon = strrchr (filename, ':');
4891 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
4892 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
4897 binary_protocol_init (filename, (long long)limit);
4898 } else if (!strcmp (opt, "nursery-canaries")) {
4899 do_verify_nursery = TRUE;
4900 sgen_set_use_managed_allocator (FALSE);
4901 enable_nursery_canaries = TRUE;
4902 } else if (!strcmp (opt, "do-not-finalize")) {
4903 do_not_finalize = TRUE;
4904 } else if (!strcmp (opt, "log-finalizers")) {
4905 log_finalizers = TRUE;
4906 } else if (!sgen_bridge_handle_gc_debug (opt)) {
4907 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
4912 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);
4913 fprintf (stderr, "Valid <option>s are:\n");
4914 fprintf (stderr, " collect-before-allocs[=<n>]\n");
4915 fprintf (stderr, " verify-before-allocs[=<n>]\n");
4916 fprintf (stderr, " check-at-minor-collections\n");
4917 fprintf (stderr, " check-mark-bits\n");
4918 fprintf (stderr, " check-nursery-pinned\n");
4919 fprintf (stderr, " verify-before-collections\n");
4920 fprintf (stderr, " verify-nursery-at-minor-gc\n");
4921 fprintf (stderr, " dump-nursery-at-minor-gc\n");
4922 fprintf (stderr, " disable-minor\n");
4923 fprintf (stderr, " disable-major\n");
4924 fprintf (stderr, " xdomain-checks\n");
4925 fprintf (stderr, " check-concurrent\n");
4926 fprintf (stderr, " clear-[nursery-]at-gc\n");
4927 fprintf (stderr, " clear-at-tlab-creation\n");
4928 fprintf (stderr, " debug-clear-at-tlab-creation\n");
4929 fprintf (stderr, " check-scan-starts\n");
4930 fprintf (stderr, " no-managed-allocator\n");
4931 fprintf (stderr, " print-allowance\n");
4932 fprintf (stderr, " print-pinning\n");
4933 fprintf (stderr, " heap-dump=<filename>\n");
4934 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
4935 fprintf (stderr, " nursery-canaries\n");
4936 fprintf (stderr, " do-not-finalize\n");
4937 fprintf (stderr, " log-finalizers\n");
4938 sgen_bridge_print_gc_debug_usage ();
4939 fprintf (stderr, "\n");
4941 usage_printed = TRUE;
4947 if (check_mark_bits_after_major_collection)
4948 nursery_clear_policy = CLEAR_AT_GC;
4950 if (major_collector.post_param_init)
4951 major_collector.post_param_init (&major_collector);
4953 if (major_collector.needs_thread_pool)
4954 sgen_workers_init (1);
4956 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
4958 memset (&remset, 0, sizeof (remset));
4960 sgen_card_table_init (&remset);
4966 mono_gc_get_gc_name (void)
4971 static MonoMethod *write_barrier_conc_method;
4972 static MonoMethod *write_barrier_noconc_method;
4975 sgen_is_critical_method (MonoMethod *method)
4977 return (method == write_barrier_conc_method || method == write_barrier_noconc_method || sgen_is_managed_allocator (method));
4981 sgen_has_critical_method (void)
4983 return write_barrier_conc_method || write_barrier_noconc_method || sgen_has_managed_allocator ();
4989 emit_nursery_check (MonoMethodBuilder *mb, int *nursery_check_return_labels, gboolean is_concurrent)
4991 int shifted_nursery_start = mono_mb_add_local (mb, &mono_defaults.int_class->byval_arg);
4993 memset (nursery_check_return_labels, 0, sizeof (int) * 2);
4994 // if (ptr_in_nursery (ptr)) return;
4996 * Masking out the bits might be faster, but we would have to use 64 bit
4997 * immediates, which might be slower.
4999 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
5000 mono_mb_emit_byte (mb, CEE_MONO_LDPTR_NURSERY_START);
5001 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5002 mono_mb_emit_byte (mb, CEE_SHR_UN);
5003 mono_mb_emit_stloc (mb, shifted_nursery_start);
5005 mono_mb_emit_ldarg (mb, 0);
5006 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5007 mono_mb_emit_byte (mb, CEE_SHR_UN);
5008 mono_mb_emit_ldloc (mb, shifted_nursery_start);
5009 nursery_check_return_labels [0] = mono_mb_emit_branch (mb, CEE_BEQ);
5011 if (!is_concurrent) {
5012 // if (!ptr_in_nursery (*ptr)) return;
5013 mono_mb_emit_ldarg (mb, 0);
5014 mono_mb_emit_byte (mb, CEE_LDIND_I);
5015 mono_mb_emit_icon (mb, DEFAULT_NURSERY_BITS);
5016 mono_mb_emit_byte (mb, CEE_SHR_UN);
5017 mono_mb_emit_ldloc (mb, shifted_nursery_start);
5018 nursery_check_return_labels [1] = mono_mb_emit_branch (mb, CEE_BNE_UN);
5024 mono_gc_get_specific_write_barrier (gboolean is_concurrent)
5027 MonoMethodBuilder *mb;
5028 MonoMethodSignature *sig;
5029 MonoMethod **write_barrier_method_addr;
5030 #ifdef MANAGED_WBARRIER
5031 int i, nursery_check_labels [2];
5033 #ifdef HAVE_KW_THREAD
5034 int stack_end_offset = -1;
5036 MONO_THREAD_VAR_OFFSET (stack_end, stack_end_offset);
5037 g_assert (stack_end_offset != -1);
5041 // FIXME: Maybe create a separate version for ctors (the branch would be
5042 // correctly predicted more times)
5044 write_barrier_method_addr = &write_barrier_conc_method;
5046 write_barrier_method_addr = &write_barrier_noconc_method;
5048 if (*write_barrier_method_addr)
5049 return *write_barrier_method_addr;
5051 /* Create the IL version of mono_gc_barrier_generic_store () */
5052 sig = mono_metadata_signature_alloc (mono_defaults.corlib, 1);
5053 sig->ret = &mono_defaults.void_class->byval_arg;
5054 sig->params [0] = &mono_defaults.int_class->byval_arg;
5057 mb = mono_mb_new (mono_defaults.object_class, "wbarrier_conc", MONO_WRAPPER_WRITE_BARRIER);
5059 mb = mono_mb_new (mono_defaults.object_class, "wbarrier_noconc", MONO_WRAPPER_WRITE_BARRIER);
5062 #ifdef MANAGED_WBARRIER
5063 emit_nursery_check (mb, nursery_check_labels, is_concurrent);
5065 addr = sgen_cardtable + ((address >> CARD_BITS) & CARD_MASK)
5069 LDC_PTR sgen_cardtable
5071 address >> CARD_BITS
5075 if (SGEN_HAVE_OVERLAPPING_CARDS) {
5076 LDC_PTR card_table_mask
5083 mono_mb_emit_byte (mb, MONO_CUSTOM_PREFIX);
5084 mono_mb_emit_byte (mb, CEE_MONO_LDPTR_CARD_TABLE);
5085 mono_mb_emit_ldarg (mb, 0);
5086 mono_mb_emit_icon (mb, CARD_BITS);
5087 mono_mb_emit_byte (mb, CEE_SHR_UN);
5088 mono_mb_emit_byte (mb, CEE_CONV_I);
5089 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
5090 #if SIZEOF_VOID_P == 8
5091 mono_mb_emit_icon8 (mb, CARD_MASK);
5093 mono_mb_emit_icon (mb, CARD_MASK);
5095 mono_mb_emit_byte (mb, CEE_CONV_I);
5096 mono_mb_emit_byte (mb, CEE_AND);
5098 mono_mb_emit_byte (mb, CEE_ADD);
5099 mono_mb_emit_icon (mb, 1);
5100 mono_mb_emit_byte (mb, CEE_STIND_I1);
5103 for (i = 0; i < 2; ++i) {
5104 if (nursery_check_labels [i])
5105 mono_mb_patch_branch (mb, nursery_check_labels [i]);
5107 mono_mb_emit_byte (mb, CEE_RET);
5109 mono_mb_emit_ldarg (mb, 0);
5110 mono_mb_emit_icall (mb, mono_gc_wbarrier_generic_nostore);
5111 mono_mb_emit_byte (mb, CEE_RET);
5114 res = mono_mb_create_method (mb, sig, 16);
5118 if (*write_barrier_method_addr) {
5119 /* Already created */
5120 mono_free_method (res);
5122 /* double-checked locking */
5123 mono_memory_barrier ();
5124 *write_barrier_method_addr = res;
5128 return *write_barrier_method_addr;
5132 mono_gc_get_write_barrier (void)
5134 return mono_gc_get_specific_write_barrier (major_collector.is_concurrent);
5138 mono_gc_get_description (void)
5140 return g_strdup ("sgen");
5144 mono_gc_set_desktop_mode (void)
5149 mono_gc_is_moving (void)
5155 mono_gc_is_disabled (void)
5161 BOOL APIENTRY mono_gc_dllmain (HMODULE module_handle, DWORD reason, LPVOID reserved)
5168 sgen_get_nursery_clear_policy (void)
5170 return nursery_clear_policy;
5174 sgen_get_array_fill_vtable (void)
5176 if (!array_fill_vtable) {
5177 static MonoClass klass;
5178 static char _vtable[sizeof(MonoVTable)+8];
5179 MonoVTable* vtable = (MonoVTable*) ALIGN_TO(_vtable, 8);
5182 MonoDomain *domain = mono_get_root_domain ();
5185 klass.element_class = mono_defaults.byte_class;
5187 klass.instance_size = sizeof (MonoArray);
5188 klass.sizes.element_size = 1;
5189 klass.name = "array_filler_type";
5191 vtable->klass = &klass;
5193 vtable->gc_descr = mono_gc_make_descr_for_array (TRUE, &bmap, 0, 1);
5196 array_fill_vtable = vtable;
5198 return array_fill_vtable;
5208 sgen_gc_unlock (void)
5210 gboolean try_free = sgen_try_free_some_memory;
5211 sgen_try_free_some_memory = FALSE;
5212 mono_mutex_unlock (&gc_mutex);
5213 MONO_GC_UNLOCKED ();
5215 mono_thread_hazardous_try_free_some ();
5219 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
5221 major_collector.iterate_live_block_ranges (callback);
5225 sgen_get_major_collector (void)
5227 return &major_collector;
5230 void mono_gc_set_skip_thread (gboolean skip)
5232 SgenThreadInfo *info = mono_thread_info_current ();
5235 info->gc_disabled = skip;
5240 sgen_get_remset (void)
5246 mono_gc_get_vtable_bits (MonoClass *class)
5249 /* FIXME move this to the bridge code */
5250 if (sgen_need_bridge_processing ()) {
5251 switch (sgen_bridge_class_kind (class)) {
5252 case GC_BRIDGE_TRANSPARENT_BRIDGE_CLASS:
5253 case GC_BRIDGE_OPAQUE_BRIDGE_CLASS:
5254 res = SGEN_GC_BIT_BRIDGE_OBJECT;
5256 case GC_BRIDGE_OPAQUE_CLASS:
5257 res = SGEN_GC_BIT_BRIDGE_OPAQUE_OBJECT;
5259 case GC_BRIDGE_TRANSPARENT_CLASS:
5263 if (fin_callbacks.is_class_finalization_aware) {
5264 if (fin_callbacks.is_class_finalization_aware (class))
5265 res |= SGEN_GC_BIT_FINALIZER_AWARE;
5271 mono_gc_register_altstack (gpointer stack, gint32 stack_size, gpointer altstack, gint32 altstack_size)
5278 sgen_check_whole_heap_stw (void)
5280 sgen_stop_world (0);
5281 sgen_clear_nursery_fragments ();
5282 sgen_check_whole_heap (FALSE);
5283 sgen_restart_world (0, NULL);
5287 sgen_gc_event_moves (void)
5289 if (moved_objects_idx) {
5290 mono_profiler_gc_moves (moved_objects, moved_objects_idx);
5291 moved_objects_idx = 0;
5296 sgen_timestamp (void)
5298 SGEN_TV_DECLARE (timestamp);
5299 SGEN_TV_GETTIME (timestamp);
5300 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
5304 mono_gc_register_finalizer_callbacks (MonoGCFinalizerCallbacks *callbacks)
5306 if (callbacks->version != MONO_GC_FINALIZER_EXTENSION_VERSION)
5307 g_error ("Invalid finalizer callback version. Expected %d but got %d\n", MONO_GC_FINALIZER_EXTENSION_VERSION, callbacks->version);
5309 fin_callbacks = *callbacks;
5316 #endif /* HAVE_SGEN_GC */