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>
191 #include "mono/metadata/sgen-gc.h"
192 #include "mono/metadata/sgen-cardtable.h"
193 #include "mono/metadata/sgen-protocol.h"
194 #include "mono/metadata/sgen-memory-governor.h"
195 #include "mono/metadata/sgen-hash-table.h"
196 #include "mono/metadata/sgen-cardtable.h"
197 #include "mono/metadata/sgen-pinning.h"
198 #include "mono/metadata/sgen-workers.h"
199 #include "mono/metadata/sgen-client.h"
200 #include "mono/metadata/sgen-pointer-queue.h"
201 #include "mono/metadata/gc-internal-agnostic.h"
202 #include "mono/utils/mono-proclib.h"
203 #include "mono/utils/mono-memory-model.h"
204 #include "mono/utils/hazard-pointer.h"
206 #include <mono/utils/memcheck.h>
208 #undef pthread_create
210 #undef pthread_detach
213 * ######################################################################
214 * ######## Types and constants used by the GC.
215 * ######################################################################
218 /* 0 means not initialized, 1 is initialized, -1 means in progress */
219 static int gc_initialized = 0;
220 /* If set, check if we need to do something every X allocations */
221 gboolean has_per_allocation_action;
222 /* If set, do a heap check every X allocation */
223 guint32 verify_before_allocs = 0;
224 /* If set, do a minor collection before every X allocation */
225 guint32 collect_before_allocs = 0;
226 /* If set, do a whole heap check before each collection */
227 static gboolean whole_heap_check_before_collection = FALSE;
228 /* If set, do a heap consistency check before each minor collection */
229 static gboolean consistency_check_at_minor_collection = FALSE;
230 /* If set, do a mod union consistency check before each finishing collection pause */
231 static gboolean mod_union_consistency_check = FALSE;
232 /* If set, check whether mark bits are consistent after major collections */
233 static gboolean check_mark_bits_after_major_collection = FALSE;
234 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
235 static gboolean check_nursery_objects_pinned = FALSE;
236 /* If set, do a few checks when the concurrent collector is used */
237 static gboolean do_concurrent_checks = FALSE;
238 /* If set, do a plausibility check on the scan_starts before and after
240 static gboolean do_scan_starts_check = FALSE;
243 * If the major collector is concurrent and this is FALSE, we will
244 * never initiate a synchronous major collection, unless requested via
247 static gboolean allow_synchronous_major = TRUE;
248 static gboolean disable_minor_collections = FALSE;
249 static gboolean disable_major_collections = FALSE;
250 static gboolean do_verify_nursery = FALSE;
251 static gboolean do_dump_nursery_content = FALSE;
252 static gboolean enable_nursery_canaries = FALSE;
254 #ifdef HEAVY_STATISTICS
255 guint64 stat_objects_alloced_degraded = 0;
256 guint64 stat_bytes_alloced_degraded = 0;
258 guint64 stat_copy_object_called_nursery = 0;
259 guint64 stat_objects_copied_nursery = 0;
260 guint64 stat_copy_object_called_major = 0;
261 guint64 stat_objects_copied_major = 0;
263 guint64 stat_scan_object_called_nursery = 0;
264 guint64 stat_scan_object_called_major = 0;
266 guint64 stat_slots_allocated_in_vain;
268 guint64 stat_nursery_copy_object_failed_from_space = 0;
269 guint64 stat_nursery_copy_object_failed_forwarded = 0;
270 guint64 stat_nursery_copy_object_failed_pinned = 0;
271 guint64 stat_nursery_copy_object_failed_to_space = 0;
273 static guint64 stat_wbarrier_add_to_global_remset = 0;
274 static guint64 stat_wbarrier_set_arrayref = 0;
275 static guint64 stat_wbarrier_arrayref_copy = 0;
276 static guint64 stat_wbarrier_generic_store = 0;
277 static guint64 stat_wbarrier_generic_store_atomic = 0;
278 static guint64 stat_wbarrier_set_root = 0;
279 static guint64 stat_wbarrier_value_copy = 0;
280 static guint64 stat_wbarrier_object_copy = 0;
283 static guint64 stat_pinned_objects = 0;
285 static guint64 time_minor_pre_collection_fragment_clear = 0;
286 static guint64 time_minor_pinning = 0;
287 static guint64 time_minor_scan_remsets = 0;
288 static guint64 time_minor_scan_pinned = 0;
289 static guint64 time_minor_scan_roots = 0;
290 static guint64 time_minor_finish_gray_stack = 0;
291 static guint64 time_minor_fragment_creation = 0;
293 static guint64 time_major_pre_collection_fragment_clear = 0;
294 static guint64 time_major_pinning = 0;
295 static guint64 time_major_scan_pinned = 0;
296 static guint64 time_major_scan_roots = 0;
297 static guint64 time_major_scan_mod_union = 0;
298 static guint64 time_major_finish_gray_stack = 0;
299 static guint64 time_major_free_bigobjs = 0;
300 static guint64 time_major_los_sweep = 0;
301 static guint64 time_major_sweep = 0;
302 static guint64 time_major_fragment_creation = 0;
304 static guint64 time_max = 0;
306 static SGEN_TV_DECLARE (time_major_conc_collection_start);
307 static SGEN_TV_DECLARE (time_major_conc_collection_end);
309 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
310 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
312 int gc_debug_level = 0;
317 mono_gc_flush_info (void)
319 fflush (gc_debug_file);
323 #define TV_DECLARE SGEN_TV_DECLARE
324 #define TV_GETTIME SGEN_TV_GETTIME
325 #define TV_ELAPSED SGEN_TV_ELAPSED
327 static SGEN_TV_DECLARE (sgen_init_timestamp);
329 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
331 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
332 #define object_is_pinned SGEN_OBJECT_IS_PINNED
333 #define pin_object SGEN_PIN_OBJECT
335 #define ptr_in_nursery sgen_ptr_in_nursery
337 #define LOAD_VTABLE SGEN_LOAD_VTABLE
340 nursery_canaries_enabled (void)
342 return enable_nursery_canaries;
345 #define safe_object_get_size sgen_safe_object_get_size
348 * ######################################################################
349 * ######## Global data.
350 * ######################################################################
352 LOCK_DECLARE (gc_mutex);
353 gboolean sgen_try_free_some_memory;
355 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
357 size_t degraded_mode = 0;
359 static mword bytes_pinned_from_failed_allocation = 0;
361 GCMemSection *nursery_section = NULL;
362 static volatile mword lowest_heap_address = ~(mword)0;
363 static volatile mword highest_heap_address = 0;
365 LOCK_DECLARE (sgen_interruption_mutex);
367 int current_collection_generation = -1;
368 static volatile gboolean concurrent_collection_in_progress = FALSE;
370 /* objects that are ready to be finalized */
371 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
372 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
374 /* registered roots: the key to the hash is the root start address */
376 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
378 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
379 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
380 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
381 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
383 static mword roots_size = 0; /* amount of memory in the root set */
385 /* The size of a TLAB */
386 /* The bigger the value, the less often we have to go to the slow path to allocate a new
387 * one, but the more space is wasted by threads not allocating much memory.
389 * FIXME: Make this self-tuning for each thread.
391 guint32 tlab_size = (1024 * 4);
393 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
395 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
397 #define ALIGN_UP SGEN_ALIGN_UP
399 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
400 MonoNativeThreadId main_gc_thread = NULL;
403 /*Object was pinned during the current collection*/
404 static mword objects_pinned;
407 * ######################################################################
408 * ######## Macros and function declarations.
409 * ######################################################################
412 typedef SgenGrayQueue GrayQueue;
414 /* forward declarations */
415 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
417 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
418 static void finish_gray_stack (int generation, ScanCopyContext ctx);
421 SgenMajorCollector major_collector;
422 SgenMinorCollector sgen_minor_collector;
423 /* FIXME: get rid of this */
424 static GrayQueue gray_queue;
426 static SgenRememberedSet remset;
428 /* The gray queue to use from the main collection thread. */
429 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
432 * The gray queue a worker job must use. If we're not parallel or
433 * concurrent, we use the main gray queue.
435 static SgenGrayQueue*
436 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
438 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
442 gray_queue_redirect (SgenGrayQueue *queue)
444 gboolean wake = FALSE;
447 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
450 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
455 g_assert (concurrent_collection_in_progress);
456 sgen_workers_ensure_awake ();
461 gray_queue_enable_redirect (SgenGrayQueue *queue)
463 if (!concurrent_collection_in_progress)
466 sgen_gray_queue_set_alloc_prepare (queue, gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
467 gray_queue_redirect (queue);
471 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
473 while (start < end) {
477 if (!*(void**)start) {
478 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
483 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
489 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
490 CHECK_CANARY_FOR_OBJECT (obj);
491 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
492 callback (obj, size, data);
493 CANARIFY_SIZE (size);
495 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
503 * sgen_add_to_global_remset:
505 * The global remset contains locations which point into newspace after
506 * a minor collection. This can happen if the objects they point to are pinned.
508 * LOCKING: If called from a parallel collector, the global remset
509 * lock must be held. For serial collectors that is not necessary.
512 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
514 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
516 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
518 if (!major_collector.is_concurrent) {
519 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
521 if (current_collection_generation == -1)
522 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
525 if (!object_is_pinned (obj))
526 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");
527 else if (sgen_cement_lookup_or_register (obj))
530 remset.record_pointer (ptr);
532 sgen_pin_stats_register_global_remset (obj);
534 SGEN_LOG (8, "Adding global remset for %p", ptr);
535 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
539 * sgen_drain_gray_stack:
541 * Scan objects in the gray stack until the stack is empty. This should be called
542 * frequently after each object is copied, to achieve better locality and cache
545 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
549 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
551 ScanObjectFunc scan_func = ctx.ops->scan_object;
552 GrayQueue *queue = ctx.queue;
554 if (current_collection_generation == GENERATION_OLD && major_collector.drain_gray_stack)
555 return major_collector.drain_gray_stack (ctx);
559 for (i = 0; i != max_objs; ++i) {
562 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
565 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
566 scan_func (obj, desc, queue);
568 } while (max_objs < 0);
573 * Addresses in the pin queue are already sorted. This function finds
574 * the object header for each address and pins the object. The
575 * addresses must be inside the nursery section. The (start of the)
576 * address array is overwritten with the addresses of the actually
577 * pinned objects. Return the number of pinned objects.
580 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
582 GCMemSection *section = nursery_section;
583 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
584 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
585 void *start_nursery = section->data;
586 void *end_nursery = section->next_data;
591 void *pinning_front = start_nursery;
593 void **definitely_pinned = start;
594 ScanObjectFunc scan_func = ctx.ops->scan_object;
595 SgenGrayQueue *queue = ctx.queue;
597 sgen_nursery_allocator_prepare_for_pinning ();
599 while (start < end) {
600 void *obj_to_pin = NULL;
601 size_t obj_to_pin_size = 0;
606 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
607 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
614 SGEN_LOG (5, "Considering pinning addr %p", addr);
615 /* We've already processed everything up to pinning_front. */
616 if (addr < pinning_front) {
622 * Find the closest scan start <= addr. We might search backward in the
623 * scan_starts array because entries might be NULL. In the worst case we
624 * start at start_nursery.
626 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
627 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
628 search_start = (void*)section->scan_starts [idx];
629 if (!search_start || search_start > addr) {
632 search_start = section->scan_starts [idx];
633 if (search_start && search_start <= addr)
636 if (!search_start || search_start > addr)
637 search_start = start_nursery;
641 * If the pinning front is closer than the scan start we found, start
642 * searching at the front.
644 if (search_start < pinning_front)
645 search_start = pinning_front;
648 * Now addr should be in an object a short distance from search_start.
650 * search_start must point to zeroed mem or point to an object.
653 size_t obj_size, canarified_obj_size;
656 if (!*(void**)search_start) {
657 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
658 /* The loop condition makes sure we don't overrun addr. */
662 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
665 * Filler arrays are marked by an invalid sync word. We don't
666 * consider them for pinning. They are not delimited by canaries,
669 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
670 CHECK_CANARY_FOR_OBJECT (search_start);
671 CANARIFY_SIZE (canarified_obj_size);
673 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
674 /* This is the object we're looking for. */
675 obj_to_pin = search_start;
676 obj_to_pin_size = canarified_obj_size;
681 /* Skip to the next object */
682 search_start = (void*)((char*)search_start + canarified_obj_size);
683 } while (search_start <= addr);
685 /* We've searched past the address we were looking for. */
687 pinning_front = search_start;
688 goto next_pin_queue_entry;
692 * We've found an object to pin. It might still be a dummy array, but we
693 * can advance the pinning front in any case.
695 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
698 * If this is a dummy array marking the beginning of a nursery
699 * fragment, we don't pin it.
701 if (sgen_client_object_is_array_fill ((GCObject*)obj_to_pin))
702 goto next_pin_queue_entry;
705 * Finally - pin the object!
707 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
708 if (do_scan_objects) {
709 scan_func (obj_to_pin, desc, queue);
711 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
712 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
713 binary_protocol_pin (obj_to_pin,
714 (gpointer)LOAD_VTABLE (obj_to_pin),
715 safe_object_get_size (obj_to_pin));
717 pin_object (obj_to_pin);
718 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
719 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
720 definitely_pinned [count] = obj_to_pin;
724 next_pin_queue_entry:
728 sgen_client_nursery_objects_pinned (definitely_pinned, count);
729 stat_pinned_objects += count;
734 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
738 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
741 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
742 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
746 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
747 * when we can't promote an object because we're out of memory.
750 sgen_pin_object (void *object, GrayQueue *queue)
753 * All pinned objects are assumed to have been staged, so we need to stage as well.
754 * Also, the count of staged objects shows that "late pinning" happened.
756 sgen_pin_stage_ptr (object);
758 SGEN_PIN_OBJECT (object);
759 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
762 sgen_pin_stats_register_object (object, safe_object_get_size (object));
764 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
767 /* Sort the addresses in array in increasing order.
768 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
771 sgen_sort_addresses (void **array, size_t size)
776 for (i = 1; i < size; ++i) {
779 size_t parent = (child - 1) / 2;
781 if (array [parent] >= array [child])
784 tmp = array [parent];
785 array [parent] = array [child];
792 for (i = size - 1; i > 0; --i) {
795 array [i] = array [0];
801 while (root * 2 + 1 <= end) {
802 size_t child = root * 2 + 1;
804 if (child < end && array [child] < array [child + 1])
806 if (array [root] >= array [child])
810 array [root] = array [child];
819 * Scan the memory between start and end and queue values which could be pointers
820 * to the area between start_nursery and end_nursery for later consideration.
821 * Typically used for thread stacks.
824 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
828 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
829 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
832 while (start < end) {
833 if (*start >= start_nursery && *start < end_nursery) {
835 * *start can point to the middle of an object
836 * note: should we handle pointing at the end of an object?
837 * pinning in C# code disallows pointing at the end of an object
838 * but there is some small chance that an optimizing C compiler
839 * may keep the only reference to an object by pointing
840 * at the end of it. We ignore this small chance for now.
841 * Pointers to the end of an object are indistinguishable
842 * from pointers to the start of the next object in memory
843 * so if we allow that we'd need to pin two objects...
844 * We queue the pointer in an array, the
845 * array will then be sorted and uniqued. This way
846 * we can coalesce several pinning pointers and it should
847 * be faster since we'd do a memory scan with increasing
848 * addresses. Note: we can align the address to the allocation
849 * alignment, so the unique process is more effective.
851 mword addr = (mword)*start;
852 addr &= ~(ALLOC_ALIGN - 1);
853 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
854 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
855 sgen_pin_stage_ptr ((void*)addr);
856 binary_protocol_pin_stage (start, (void*)addr);
861 * FIXME: It seems we're registering objects from all over the heap
862 * (at least from the nursery and the LOS), but we're only
863 * registering pinned addresses in the nursery. What's up with
866 * Also, why wouldn't we register addresses once the pinning queue
867 * is sorted and uniqued?
869 if (ptr_in_nursery ((void*)addr))
870 sgen_pin_stats_register_address ((char*)addr, pin_type);
875 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
879 * The first thing we do in a collection is to identify pinned objects.
880 * This function considers all the areas of memory that need to be
881 * conservatively scanned.
884 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
888 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);
889 /* objects pinned from the API are inside these roots */
890 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
891 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
892 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
893 } SGEN_HASH_TABLE_FOREACH_END;
894 /* now deal with the thread stacks
895 * in the future we should be able to conservatively scan only:
896 * *) the cpu registers
897 * *) the unmanaged stack frames
898 * *) the _last_ managed stack frame
899 * *) pointers slots in managed frames
901 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
905 unpin_objects_from_queue (SgenGrayQueue *queue)
910 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
913 g_assert (SGEN_OBJECT_IS_PINNED (addr));
914 SGEN_UNPIN_OBJECT (addr);
919 single_arg_user_copy_or_mark (void **obj, void *gc_data)
921 ScanCopyContext *ctx = gc_data;
922 ctx->ops->copy_or_mark_object (obj, ctx->queue);
926 * The memory area from start_root to end_root contains pointers to objects.
927 * Their position is precisely described by @desc (this means that the pointer
928 * can be either NULL or the pointer to the start of an object).
929 * This functions copies them to to_space updates them.
931 * This function is not thread-safe!
934 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
936 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
937 SgenGrayQueue *queue = ctx.queue;
939 switch (desc & ROOT_DESC_TYPE_MASK) {
940 case ROOT_DESC_BITMAP:
941 desc >>= ROOT_DESC_TYPE_SHIFT;
943 if ((desc & 1) && *start_root) {
944 copy_func (start_root, queue);
945 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
951 case ROOT_DESC_COMPLEX: {
952 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
953 gsize bwords = (*bitmap_data) - 1;
954 void **start_run = start_root;
956 while (bwords-- > 0) {
957 gsize bmap = *bitmap_data++;
958 void **objptr = start_run;
960 if ((bmap & 1) && *objptr) {
961 copy_func (objptr, queue);
962 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
967 start_run += GC_BITS_PER_WORD;
971 case ROOT_DESC_USER: {
972 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
973 marker (start_root, single_arg_user_copy_or_mark, &ctx);
976 case ROOT_DESC_RUN_LEN:
977 g_assert_not_reached ();
979 g_assert_not_reached ();
984 reset_heap_boundaries (void)
986 lowest_heap_address = ~(mword)0;
987 highest_heap_address = 0;
991 sgen_update_heap_boundaries (mword low, mword high)
996 old = lowest_heap_address;
999 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1002 old = highest_heap_address;
1005 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1009 * Allocate and setup the data structures needed to be able to allocate objects
1010 * in the nursery. The nursery is stored in nursery_section.
1013 alloc_nursery (void)
1015 GCMemSection *section;
1020 if (nursery_section)
1022 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1023 /* later we will alloc a larger area for the nursery but only activate
1024 * what we need. The rest will be used as expansion if we have too many pinned
1025 * objects in the existing nursery.
1027 /* FIXME: handle OOM */
1028 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1030 alloc_size = sgen_nursery_size;
1032 /* If there isn't enough space even for the nursery we should simply abort. */
1033 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1035 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1036 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1037 SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)sgen_gc_get_total_heap_allocation ());
1038 section->data = section->next_data = data;
1039 section->size = alloc_size;
1040 section->end_data = data + sgen_nursery_size;
1041 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1042 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1043 section->num_scan_start = scan_starts;
1045 nursery_section = section;
1047 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1051 mono_gc_get_logfile (void)
1053 return gc_debug_file;
1057 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1059 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1060 SgenGrayQueue *queue = ctx.queue;
1063 for (i = 0; i < fin_queue->next_slot; ++i) {
1064 void *obj = fin_queue->data [i];
1067 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1068 copy_func (&fin_queue->data [i], queue);
1073 generation_name (int generation)
1075 switch (generation) {
1076 case GENERATION_NURSERY: return "nursery";
1077 case GENERATION_OLD: return "old";
1078 default: g_assert_not_reached ();
1083 sgen_generation_name (int generation)
1085 return generation_name (generation);
1089 finish_gray_stack (int generation, ScanCopyContext ctx)
1093 int done_with_ephemerons, ephemeron_rounds = 0;
1094 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1095 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1096 SgenGrayQueue *queue = ctx.queue;
1099 * We copied all the reachable objects. Now it's the time to copy
1100 * the objects that were not referenced by the roots, but by the copied objects.
1101 * we built a stack of objects pointed to by gray_start: they are
1102 * additional roots and we may add more items as we go.
1103 * We loop until gray_start == gray_objects which means no more objects have
1104 * been added. Note this is iterative: no recursion is involved.
1105 * We need to walk the LO list as well in search of marked big objects
1106 * (use a flag since this is needed only on major collections). We need to loop
1107 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1108 * To achieve better cache locality and cache usage, we drain the gray stack
1109 * frequently, after each object is copied, and just finish the work here.
1111 sgen_drain_gray_stack (-1, ctx);
1113 SGEN_LOG (2, "%s generation done", generation_name (generation));
1116 Reset bridge data, we might have lingering data from a previous collection if this is a major
1117 collection trigged by minor overflow.
1119 We must reset the gathered bridges since their original block might be evacuated due to major
1120 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1122 if (sgen_client_bridge_need_processing ())
1123 sgen_client_bridge_reset_data ();
1126 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1127 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1128 * objects that are in fact reachable.
1130 done_with_ephemerons = 0;
1132 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1133 sgen_drain_gray_stack (-1, ctx);
1135 } while (!done_with_ephemerons);
1137 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1139 if (sgen_client_bridge_need_processing ()) {
1140 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1141 sgen_drain_gray_stack (-1, ctx);
1142 sgen_collect_bridge_objects (generation, ctx);
1143 if (generation == GENERATION_OLD)
1144 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1147 Do the first bridge step here, as the collector liveness state will become useless after that.
1149 An important optimization is to only proccess the possibly dead part of the object graph and skip
1150 over all live objects as we transitively know everything they point must be alive too.
1152 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1154 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1155 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1158 sgen_client_bridge_processing_stw_step ();
1162 Make sure we drain the gray stack before processing disappearing links and finalizers.
1163 If we don't make sure it is empty we might wrongly see a live object as dead.
1165 sgen_drain_gray_stack (-1, ctx);
1168 We must clear weak links that don't track resurrection before processing object ready for
1169 finalization so they can be cleared before that.
1171 sgen_null_link_in_range (generation, TRUE, ctx);
1172 if (generation == GENERATION_OLD)
1173 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1176 /* walk the finalization queue and move also the objects that need to be
1177 * finalized: use the finalized objects as new roots so the objects they depend
1178 * on are also not reclaimed. As with the roots above, only objects in the nursery
1179 * are marked/copied.
1181 sgen_finalize_in_range (generation, ctx);
1182 if (generation == GENERATION_OLD)
1183 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1184 /* drain the new stack that might have been created */
1185 SGEN_LOG (6, "Precise scan of gray area post fin");
1186 sgen_drain_gray_stack (-1, ctx);
1189 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1191 done_with_ephemerons = 0;
1193 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1194 sgen_drain_gray_stack (-1, ctx);
1196 } while (!done_with_ephemerons);
1198 sgen_client_clear_unreachable_ephemerons (ctx);
1201 * We clear togglerefs only after all possible chances of revival are done.
1202 * This is semantically more inline with what users expect and it allows for
1203 * user finalizers to correctly interact with TR objects.
1205 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1208 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %ld usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1211 * handle disappearing links
1212 * Note we do this after checking the finalization queue because if an object
1213 * survives (at least long enough to be finalized) we don't clear the link.
1214 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1215 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1218 g_assert (sgen_gray_object_queue_is_empty (queue));
1220 sgen_null_link_in_range (generation, FALSE, ctx);
1221 if (generation == GENERATION_OLD)
1222 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1223 if (sgen_gray_object_queue_is_empty (queue))
1225 sgen_drain_gray_stack (-1, ctx);
1228 g_assert (sgen_gray_object_queue_is_empty (queue));
1230 sgen_gray_object_queue_trim_free_list (queue);
1234 sgen_check_section_scan_starts (GCMemSection *section)
1237 for (i = 0; i < section->num_scan_start; ++i) {
1238 if (section->scan_starts [i]) {
1239 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1240 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1246 check_scan_starts (void)
1248 if (!do_scan_starts_check)
1250 sgen_check_section_scan_starts (nursery_section);
1251 major_collector.check_scan_starts ();
1255 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1259 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1260 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1261 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1262 } SGEN_HASH_TABLE_FOREACH_END;
1268 static gboolean inited = FALSE;
1273 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1275 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1276 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1277 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1278 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1279 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1280 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1282 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1283 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1284 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1285 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1286 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1287 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1288 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1289 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1290 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1291 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1293 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1295 #ifdef HEAVY_STATISTICS
1296 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1297 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_arrayref);
1298 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1299 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1300 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1301 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1302 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_value_copy);
1303 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_object_copy);
1305 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1306 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1308 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1309 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1310 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1311 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1313 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1314 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1316 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1318 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1319 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1320 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1321 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1323 sgen_nursery_allocator_init_heavy_stats ();
1331 reset_pinned_from_failed_allocation (void)
1333 bytes_pinned_from_failed_allocation = 0;
1337 sgen_set_pinned_from_failed_allocation (mword objsize)
1339 bytes_pinned_from_failed_allocation += objsize;
1343 sgen_collection_is_concurrent (void)
1345 switch (current_collection_generation) {
1346 case GENERATION_NURSERY:
1348 case GENERATION_OLD:
1349 return concurrent_collection_in_progress;
1351 g_error ("Invalid current generation %d", current_collection_generation);
1357 sgen_concurrent_collection_in_progress (void)
1359 return concurrent_collection_in_progress;
1363 SgenThreadPoolJob job;
1364 SgenObjectOperations *ops;
1368 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
1370 WorkerData *worker_data = worker_data_untyped;
1371 ScanJob *job_data = (ScanJob*)job;
1372 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1373 remset.scan_remsets (ctx);
1377 SgenThreadPoolJob job;
1378 SgenObjectOperations *ops;
1382 } ScanFromRegisteredRootsJob;
1385 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1387 WorkerData *worker_data = worker_data_untyped;
1388 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1389 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1391 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1395 SgenThreadPoolJob job;
1396 SgenObjectOperations *ops;
1399 } ScanThreadDataJob;
1402 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1404 WorkerData *worker_data = worker_data_untyped;
1405 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1406 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1408 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1412 SgenThreadPoolJob job;
1413 SgenObjectOperations *ops;
1414 SgenPointerQueue *queue;
1415 } ScanFinalizerEntriesJob;
1418 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1420 WorkerData *worker_data = worker_data_untyped;
1421 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1422 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1424 scan_finalizer_entries (job_data->queue, ctx);
1428 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1430 WorkerData *worker_data = worker_data_untyped;
1431 ScanJob *job_data = (ScanJob*)job;
1432 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1434 g_assert (concurrent_collection_in_progress);
1435 major_collector.scan_card_table (TRUE, ctx);
1439 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1441 WorkerData *worker_data = worker_data_untyped;
1442 ScanJob *job_data = (ScanJob*)job;
1443 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1445 g_assert (concurrent_collection_in_progress);
1446 sgen_los_scan_card_table (TRUE, ctx);
1450 init_gray_queue (void)
1452 if (sgen_collection_is_concurrent ())
1453 sgen_workers_init_distribute_gray_queue ();
1454 sgen_gray_object_queue_init (&gray_queue, NULL);
1458 enqueue_scan_from_roots_jobs (char *heap_start, char *heap_end, SgenObjectOperations *ops)
1460 ScanFromRegisteredRootsJob *scrrj;
1461 ScanThreadDataJob *stdj;
1462 ScanFinalizerEntriesJob *sfej;
1464 /* registered roots, this includes static fields */
1466 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1468 scrrj->heap_start = heap_start;
1469 scrrj->heap_end = heap_end;
1470 scrrj->root_type = ROOT_TYPE_NORMAL;
1471 sgen_workers_enqueue_job (&scrrj->job);
1473 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1475 scrrj->heap_start = heap_start;
1476 scrrj->heap_end = heap_end;
1477 scrrj->root_type = ROOT_TYPE_WBARRIER;
1478 sgen_workers_enqueue_job (&scrrj->job);
1482 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1483 stdj->heap_start = heap_start;
1484 stdj->heap_end = heap_end;
1485 sgen_workers_enqueue_job (&stdj->job);
1487 /* Scan the list of objects ready for finalization. */
1489 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1490 sfej->queue = &fin_ready_queue;
1492 sgen_workers_enqueue_job (&sfej->job);
1494 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1495 sfej->queue = &critical_fin_queue;
1497 sgen_workers_enqueue_job (&sfej->job);
1501 * Perform a nursery collection.
1503 * Return whether any objects were late-pinned due to being out of memory.
1506 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
1508 gboolean needs_major;
1509 size_t max_garbage_amount;
1511 mword fragment_total;
1513 SgenObjectOperations *object_ops = &sgen_minor_collector.serial_ops;
1514 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gray_queue);
1518 if (disable_minor_collections)
1521 TV_GETTIME (last_minor_collection_start_tv);
1522 atv = last_minor_collection_start_tv;
1524 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1526 if (do_verify_nursery || do_dump_nursery_content)
1527 sgen_debug_verify_nursery (do_dump_nursery_content);
1529 current_collection_generation = GENERATION_NURSERY;
1531 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1533 reset_pinned_from_failed_allocation ();
1535 check_scan_starts ();
1537 sgen_nursery_alloc_prepare_for_minor ();
1541 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
1542 /* FIXME: optimize later to use the higher address where an object can be present */
1543 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
1545 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 ()));
1546 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
1547 g_assert (nursery_section->size >= max_garbage_amount);
1549 /* world must be stopped already */
1551 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1553 sgen_client_pre_collection_checks ();
1555 nursery_section->next_data = nursery_next;
1557 major_collector.start_nursery_collection ();
1559 sgen_memgov_minor_collection_start ();
1563 gc_stats.minor_gc_count ++;
1565 if (whole_heap_check_before_collection) {
1566 sgen_clear_nursery_fragments ();
1567 sgen_check_whole_heap (finish_up_concurrent_mark);
1569 if (consistency_check_at_minor_collection)
1570 sgen_check_consistency ();
1572 sgen_process_fin_stage_entries ();
1573 sgen_process_dislink_stage_entries ();
1575 /* pin from pinned handles */
1576 sgen_init_pinning ();
1577 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1578 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
1579 /* pin cemented objects */
1580 sgen_pin_cemented_objects ();
1581 /* identify pinned objects */
1582 sgen_optimize_pin_queue ();
1583 sgen_pinning_setup_section (nursery_section);
1585 pin_objects_in_nursery (FALSE, ctx);
1586 sgen_pinning_trim_queue_to_section (nursery_section);
1589 time_minor_pinning += TV_ELAPSED (btv, atv);
1590 SGEN_LOG (2, "Finding pinned pointers: %zd in %ld usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
1591 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1594 * FIXME: When we finish a concurrent collection we do a nursery collection first,
1595 * as part of which we scan the card table. Then, later, we scan the mod union
1596 * cardtable. We should only have to do one.
1598 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
1599 sj->ops = object_ops;
1600 sgen_workers_enqueue_job (&sj->job);
1602 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1604 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1605 SGEN_LOG (2, "Old generation scan: %ld usecs", TV_ELAPSED (atv, btv));
1607 sgen_drain_gray_stack (-1, ctx);
1609 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1610 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1613 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1615 enqueue_scan_from_roots_jobs (sgen_get_nursery_start (), nursery_next, object_ops);
1618 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1620 finish_gray_stack (GENERATION_NURSERY, ctx);
1623 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1624 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1626 if (objects_pinned) {
1627 sgen_optimize_pin_queue ();
1628 sgen_pinning_setup_section (nursery_section);
1631 /* walk the pin_queue, build up the fragment list of free memory, unmark
1632 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1635 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1636 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1637 if (!fragment_total)
1640 /* Clear TLABs for all threads */
1641 sgen_clear_tlabs ();
1643 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1645 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1646 SGEN_LOG (2, "Fragment creation: %ld usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1648 if (consistency_check_at_minor_collection)
1649 sgen_check_major_refs ();
1651 major_collector.finish_nursery_collection ();
1653 TV_GETTIME (last_minor_collection_end_tv);
1654 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1656 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1658 /* prepare the pin queue for the next collection */
1659 sgen_finish_pinning ();
1660 if (sgen_have_pending_finalizers ()) {
1661 SGEN_LOG (4, "Finalizer-thread wakeup");
1662 sgen_client_finalize_notify ();
1664 sgen_pin_stats_reset ();
1665 /* clear cemented hash */
1666 sgen_cement_clear_below_threshold ();
1668 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
1670 remset.finish_minor_collection ();
1672 check_scan_starts ();
1674 binary_protocol_flush_buffers (FALSE);
1676 sgen_memgov_minor_collection_end ();
1678 /*objects are late pinned because of lack of memory, so a major is a good call*/
1679 needs_major = objects_pinned > 0;
1680 current_collection_generation = -1;
1683 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1685 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1686 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1692 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
1695 * This is called on all objects in the nursery, including pinned ones, so we need
1696 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
1698 ctx->ops->scan_object (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
1702 scan_nursery_objects (ScanCopyContext ctx)
1704 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1705 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
1709 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1710 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1711 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1712 } CopyOrMarkFromRootsMode;
1715 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMode mode, gboolean scan_whole_nursery, SgenObjectOperations *object_ops)
1720 /* FIXME: only use these values for the precise scan
1721 * note that to_space pointers should be excluded anyway...
1723 char *heap_start = NULL;
1724 char *heap_end = (char*)-1;
1725 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, WORKERS_DISTRIBUTE_GRAY_QUEUE);
1726 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1728 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1730 if (scan_whole_nursery)
1731 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "Scanning whole nursery only makes sense when we're finishing a concurrent collection.");
1734 /*This cleans up unused fragments */
1735 sgen_nursery_allocator_prepare_for_pinning ();
1737 if (do_concurrent_checks)
1738 sgen_debug_check_nursery_is_clean ();
1740 /* The concurrent collector doesn't touch the nursery. */
1741 sgen_nursery_alloc_prepare_for_major ();
1748 /* Pinning depends on this */
1749 sgen_clear_nursery_fragments ();
1751 if (whole_heap_check_before_collection)
1752 sgen_check_whole_heap (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT);
1755 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1757 if (!sgen_collection_is_concurrent ())
1758 nursery_section->next_data = sgen_get_nursery_end ();
1759 /* we should also coalesce scanning from sections close to each other
1760 * and deal with pointers outside of the sections later.
1765 sgen_client_pre_collection_checks ();
1768 /* Remsets are not useful for a major collection */
1769 remset.clear_cards ();
1772 sgen_process_fin_stage_entries ();
1773 sgen_process_dislink_stage_entries ();
1776 sgen_init_pinning ();
1777 SGEN_LOG (6, "Collecting pinned addresses");
1778 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1780 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1781 if (major_collector.is_concurrent) {
1783 * The concurrent major collector cannot evict
1784 * yet, so we need to pin cemented objects to
1785 * not break some asserts.
1787 * FIXME: We could evict now!
1789 sgen_pin_cemented_objects ();
1793 sgen_optimize_pin_queue ();
1795 sgen_client_collecting_major_1 ();
1798 * pin_queue now contains all candidate pointers, sorted and
1799 * uniqued. We must do two passes now to figure out which
1800 * objects are pinned.
1802 * The first is to find within the pin_queue the area for each
1803 * section. This requires that the pin_queue be sorted. We
1804 * also process the LOS objects and pinned chunks here.
1806 * The second, destructive, pass is to reduce the section
1807 * areas to pointers to the actually pinned objects.
1809 SGEN_LOG (6, "Pinning from sections");
1810 /* first pass for the sections */
1811 sgen_find_section_pin_queue_start_end (nursery_section);
1812 /* identify possible pointers to the insize of large objects */
1813 SGEN_LOG (6, "Pinning from large objects");
1814 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1816 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1817 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((GCObject*)(bigobj->data))));
1819 if (sgen_los_object_is_pinned (bigobj->data)) {
1820 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1823 sgen_los_pin_object (bigobj->data);
1824 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1825 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
1826 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((GCObject*) bigobj->data));
1827 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1828 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1829 (unsigned long)sgen_los_object_size (bigobj));
1831 sgen_client_pinned_los_object (bigobj->data);
1834 /* second pass for the sections */
1837 * Concurrent mark never follows references into the nursery. In the start and
1838 * finish pauses we must scan live nursery objects, though.
1840 * In the finish pause we do this conservatively by scanning all nursery objects.
1841 * Previously we would only scan pinned objects here. We assumed that all objects
1842 * that were pinned during the nursery collection immediately preceding this finish
1843 * mark would be pinned again here. Due to the way we get the stack end for the GC
1844 * thread, however, that's not necessarily the case: we scan part of the stack used
1845 * by the GC itself, which changes constantly, so pinning isn't entirely
1848 * The split nursery also complicates things because non-pinned objects can survive
1849 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
1851 * In the future we shouldn't do a preceding nursery collection at all and instead
1852 * do the finish pause with promotion from the nursery.
1854 * A further complication arises when we have late-pinned objects from the preceding
1855 * nursery collection. Those are the result of being out of memory when trying to
1856 * evacuate objects. They won't be found from the roots, so we just scan the whole
1859 * Non-concurrent mark evacuates from the nursery, so it's
1860 * sufficient to just scan pinned nursery objects.
1862 if (scan_whole_nursery || mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT || (concurrent && sgen_minor_collector.is_split)) {
1863 scan_nursery_objects (ctx);
1865 pin_objects_in_nursery (concurrent, ctx);
1866 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1867 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1870 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
1871 if (old_next_pin_slot)
1872 *old_next_pin_slot = sgen_get_pinned_count ();
1875 time_major_pinning += TV_ELAPSED (atv, btv);
1876 SGEN_LOG (2, "Finding pinned pointers: %zd in %ld usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
1877 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1879 major_collector.init_to_space ();
1882 * The concurrent collector doesn't move objects, neither on
1883 * the major heap nor in the nursery, so we can mark even
1884 * before pinning has finished. For the non-concurrent
1885 * collector we start the workers after pinning.
1887 if (mode != COPY_OR_MARK_FROM_ROOTS_SERIAL) {
1888 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1889 sgen_workers_start_all_workers (object_ops);
1890 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
1893 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1894 main_gc_thread = mono_native_thread_self ();
1897 sgen_client_collecting_major_2 ();
1900 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1902 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1905 * FIXME: is this the right context? It doesn't seem to contain a copy function
1906 * unless we're concurrent.
1908 enqueue_scan_from_roots_jobs (heap_start, heap_end, object_ops);
1911 time_major_scan_roots += TV_ELAPSED (atv, btv);
1913 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1916 /* Mod union card table */
1917 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ScanJob));
1918 sj->ops = object_ops;
1919 sgen_workers_enqueue_job (&sj->job);
1921 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ScanJob));
1922 sj->ops = object_ops;
1923 sgen_workers_enqueue_job (&sj->job);
1926 time_major_scan_mod_union += TV_ELAPSED (btv, atv);
1931 major_finish_copy_or_mark (void)
1933 if (!concurrent_collection_in_progress)
1937 * Prepare the pin queue for the next collection. Since pinning runs on the worker
1938 * threads we must wait for the jobs to finish before we can reset it.
1940 sgen_workers_wait_for_jobs_finished ();
1941 sgen_finish_pinning ();
1943 sgen_pin_stats_reset ();
1945 if (do_concurrent_checks)
1946 sgen_debug_check_nursery_is_clean ();
1950 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
1952 SgenObjectOperations *object_ops;
1954 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
1956 current_collection_generation = GENERATION_OLD;
1958 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
1960 sgen_cement_reset ();
1963 g_assert (major_collector.is_concurrent);
1964 concurrent_collection_in_progress = TRUE;
1966 object_ops = &major_collector.major_ops_concurrent_start;
1968 object_ops = &major_collector.major_ops_serial;
1971 reset_pinned_from_failed_allocation ();
1973 sgen_memgov_major_collection_start ();
1975 //count_ref_nonref_objs ();
1976 //consistency_check ();
1978 check_scan_starts ();
1981 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
1982 gc_stats.major_gc_count ++;
1984 if (major_collector.start_major_collection)
1985 major_collector.start_major_collection ();
1987 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);
1988 major_finish_copy_or_mark ();
1992 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean forced, gboolean scan_whole_nursery)
1994 ScannedObjectCounts counts;
1995 SgenObjectOperations *object_ops;
2001 if (concurrent_collection_in_progress) {
2002 object_ops = &major_collector.major_ops_concurrent_finish;
2004 major_copy_or_mark_from_roots (NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, scan_whole_nursery, object_ops);
2006 major_finish_copy_or_mark ();
2008 sgen_workers_join ();
2010 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2012 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2013 main_gc_thread = NULL;
2016 if (do_concurrent_checks)
2017 sgen_debug_check_nursery_is_clean ();
2019 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2020 object_ops = &major_collector.major_ops_serial;
2024 * The workers have stopped so we need to finish gray queue
2025 * work that might result from finalization in the main GC
2026 * thread. Redirection must therefore be turned off.
2028 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2029 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2031 /* all the objects in the heap */
2032 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gray_queue));
2034 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2036 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2038 if (objects_pinned) {
2039 g_assert (!concurrent_collection_in_progress);
2042 * This is slow, but we just OOM'd.
2044 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2045 * queue is laid out at this point.
2047 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2049 * We need to reestablish all pinned nursery objects in the pin queue
2050 * because they're needed for fragment creation. Unpinning happens by
2051 * walking the whole queue, so it's not necessary to reestablish where major
2052 * heap block pins are - all we care is that they're still in there
2055 sgen_optimize_pin_queue ();
2056 sgen_find_section_pin_queue_start_end (nursery_section);
2060 reset_heap_boundaries ();
2061 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2063 if (!concurrent_collection_in_progress) {
2064 /* walk the pin_queue, build up the fragment list of free memory, unmark
2065 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2068 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2071 /* prepare the pin queue for the next collection */
2072 sgen_finish_pinning ();
2074 /* Clear TLABs for all threads */
2075 sgen_clear_tlabs ();
2077 sgen_pin_stats_reset ();
2080 sgen_cement_clear_below_threshold ();
2082 if (check_mark_bits_after_major_collection)
2083 sgen_check_heap_marked (concurrent_collection_in_progress);
2086 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2088 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2091 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2096 time_major_los_sweep += TV_ELAPSED (atv, btv);
2098 major_collector.sweep ();
2100 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2103 time_major_sweep += TV_ELAPSED (btv, atv);
2105 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2107 if (sgen_have_pending_finalizers ()) {
2108 SGEN_LOG (4, "Finalizer-thread wakeup");
2109 sgen_client_finalize_notify ();
2112 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2114 sgen_memgov_major_collection_end (forced);
2115 current_collection_generation = -1;
2117 memset (&counts, 0, sizeof (ScannedObjectCounts));
2118 major_collector.finish_major_collection (&counts);
2120 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2122 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2123 if (concurrent_collection_in_progress)
2124 concurrent_collection_in_progress = FALSE;
2126 check_scan_starts ();
2128 binary_protocol_flush_buffers (FALSE);
2130 //consistency_check ();
2132 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2136 major_do_collection (const char *reason, gboolean forced)
2138 TV_DECLARE (time_start);
2139 TV_DECLARE (time_end);
2140 size_t old_next_pin_slot;
2142 if (disable_major_collections)
2145 if (major_collector.get_and_reset_num_major_objects_marked) {
2146 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2147 g_assert (!num_marked);
2150 /* world must be stopped already */
2151 TV_GETTIME (time_start);
2153 major_start_collection (FALSE, &old_next_pin_slot);
2154 major_finish_collection (reason, old_next_pin_slot, forced, FALSE);
2156 TV_GETTIME (time_end);
2157 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2159 /* FIXME: also report this to the user, preferably in gc-end. */
2160 if (major_collector.get_and_reset_num_major_objects_marked)
2161 major_collector.get_and_reset_num_major_objects_marked ();
2163 return bytes_pinned_from_failed_allocation > 0;
2167 major_start_concurrent_collection (const char *reason)
2169 TV_DECLARE (time_start);
2170 TV_DECLARE (time_end);
2171 long long num_objects_marked;
2173 if (disable_major_collections)
2176 TV_GETTIME (time_start);
2177 SGEN_TV_GETTIME (time_major_conc_collection_start);
2179 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2180 g_assert (num_objects_marked == 0);
2182 binary_protocol_concurrent_start ();
2184 // FIXME: store reason and pass it when finishing
2185 major_start_collection (TRUE, NULL);
2187 gray_queue_redirect (&gray_queue);
2189 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2191 TV_GETTIME (time_end);
2192 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2194 current_collection_generation = -1;
2198 * Returns whether the major collection has finished.
2201 major_should_finish_concurrent_collection (void)
2203 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
2204 return sgen_workers_all_done ();
2208 major_update_concurrent_collection (void)
2210 TV_DECLARE (total_start);
2211 TV_DECLARE (total_end);
2213 TV_GETTIME (total_start);
2215 binary_protocol_concurrent_update ();
2217 major_collector.update_cardtable_mod_union ();
2218 sgen_los_update_cardtable_mod_union ();
2220 TV_GETTIME (total_end);
2221 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2225 major_finish_concurrent_collection (gboolean forced)
2227 TV_DECLARE (total_start);
2228 TV_DECLARE (total_end);
2229 gboolean late_pinned;
2230 SgenGrayQueue unpin_queue;
2231 memset (&unpin_queue, 0, sizeof (unpin_queue));
2233 TV_GETTIME (total_start);
2235 binary_protocol_concurrent_finish ();
2238 * The major collector can add global remsets which are processed in the finishing
2239 * nursery collection, below. That implies that the workers must have finished
2240 * marking before the nursery collection is allowed to run, otherwise we might miss
2243 sgen_workers_wait ();
2245 SGEN_TV_GETTIME (time_major_conc_collection_end);
2246 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2248 major_collector.update_cardtable_mod_union ();
2249 sgen_los_update_cardtable_mod_union ();
2251 late_pinned = collect_nursery (&unpin_queue, TRUE);
2253 if (mod_union_consistency_check)
2254 sgen_check_mod_union_consistency ();
2256 current_collection_generation = GENERATION_OLD;
2257 major_finish_collection ("finishing", -1, forced, late_pinned);
2259 if (whole_heap_check_before_collection)
2260 sgen_check_whole_heap (FALSE);
2262 unpin_objects_from_queue (&unpin_queue);
2263 sgen_gray_object_queue_deinit (&unpin_queue);
2265 TV_GETTIME (total_end);
2266 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2268 current_collection_generation = -1;
2272 * Ensure an allocation request for @size will succeed by freeing enough memory.
2274 * LOCKING: The GC lock MUST be held.
2277 sgen_ensure_free_space (size_t size)
2279 int generation_to_collect = -1;
2280 const char *reason = NULL;
2282 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
2283 if (sgen_need_major_collection (size)) {
2284 reason = "LOS overflow";
2285 generation_to_collect = GENERATION_OLD;
2288 if (degraded_mode) {
2289 if (sgen_need_major_collection (size)) {
2290 reason = "Degraded mode overflow";
2291 generation_to_collect = GENERATION_OLD;
2293 } else if (sgen_need_major_collection (size)) {
2294 reason = "Minor allowance";
2295 generation_to_collect = GENERATION_OLD;
2297 generation_to_collect = GENERATION_NURSERY;
2298 reason = "Nursery full";
2302 if (generation_to_collect == -1) {
2303 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2304 generation_to_collect = GENERATION_OLD;
2305 reason = "Finish concurrent collection";
2309 if (generation_to_collect == -1)
2311 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
2315 * LOCKING: Assumes the GC lock is held.
2318 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
2320 TV_DECLARE (gc_start);
2321 TV_DECLARE (gc_end);
2322 TV_DECLARE (gc_total_start);
2323 TV_DECLARE (gc_total_end);
2324 GGTimingInfo infos [2];
2325 int overflow_generation_to_collect = -1;
2326 int oldest_generation_collected = generation_to_collect;
2327 const char *overflow_reason = NULL;
2329 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2331 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2333 TV_GETTIME (gc_start);
2335 sgen_stop_world (generation_to_collect);
2337 TV_GETTIME (gc_total_start);
2339 if (concurrent_collection_in_progress) {
2341 * We update the concurrent collection. If it finished, we're done. If
2342 * not, and we've been asked to do a nursery collection, we do that.
2344 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
2347 major_finish_concurrent_collection (wait_to_finish);
2348 oldest_generation_collected = GENERATION_OLD;
2350 sgen_workers_signal_start_nursery_collection_and_wait ();
2352 major_update_concurrent_collection ();
2353 if (generation_to_collect == GENERATION_NURSERY)
2354 collect_nursery (NULL, FALSE);
2356 sgen_workers_signal_finish_nursery_collection ();
2363 * If we've been asked to do a major collection, and the major collector wants to
2364 * run synchronously (to evacuate), we set the flag to do that.
2366 if (generation_to_collect == GENERATION_OLD &&
2367 allow_synchronous_major &&
2368 major_collector.want_synchronous_collection &&
2369 *major_collector.want_synchronous_collection) {
2370 wait_to_finish = TRUE;
2373 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
2376 * There's no concurrent collection in progress. Collect the generation we're asked
2377 * to collect. If the major collector is concurrent and we're not forced to wait,
2378 * start a concurrent collection.
2380 // FIXME: extract overflow reason
2381 if (generation_to_collect == GENERATION_NURSERY) {
2382 if (collect_nursery (NULL, FALSE)) {
2383 overflow_generation_to_collect = GENERATION_OLD;
2384 overflow_reason = "Minor overflow";
2387 if (major_collector.is_concurrent && !wait_to_finish) {
2388 collect_nursery (NULL, FALSE);
2389 major_start_concurrent_collection (reason);
2390 // FIXME: set infos[0] properly
2394 if (major_do_collection (reason, wait_to_finish)) {
2395 overflow_generation_to_collect = GENERATION_NURSERY;
2396 overflow_reason = "Excessive pinning";
2400 TV_GETTIME (gc_end);
2402 memset (infos, 0, sizeof (infos));
2403 infos [0].generation = generation_to_collect;
2404 infos [0].reason = reason;
2405 infos [0].is_overflow = FALSE;
2406 infos [1].generation = -1;
2407 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
2409 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
2411 if (overflow_generation_to_collect != -1) {
2413 * We need to do an overflow collection, either because we ran out of memory
2414 * or the nursery is fully pinned.
2417 infos [1].generation = overflow_generation_to_collect;
2418 infos [1].reason = overflow_reason;
2419 infos [1].is_overflow = TRUE;
2422 if (overflow_generation_to_collect == GENERATION_NURSERY)
2423 collect_nursery (NULL, FALSE);
2425 major_do_collection (overflow_reason, wait_to_finish);
2427 TV_GETTIME (gc_end);
2428 infos [1].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
2430 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2433 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2435 /* this also sets the proper pointers for the next allocation */
2436 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2437 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2438 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2439 sgen_dump_pin_queue ();
2444 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2446 TV_GETTIME (gc_total_end);
2447 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2449 sgen_restart_world (oldest_generation_collected, infos);
2453 * ######################################################################
2454 * ######## Memory allocation from the OS
2455 * ######################################################################
2456 * This section of code deals with getting memory from the OS and
2457 * allocating memory for GC-internal data structures.
2458 * Internal memory can be handled with a freelist for small objects.
2464 G_GNUC_UNUSED static void
2465 report_internal_mem_usage (void)
2467 printf ("Internal memory usage:\n");
2468 sgen_report_internal_mem_usage ();
2469 printf ("Pinned memory usage:\n");
2470 major_collector.report_pinned_memory_usage ();
2474 * ######################################################################
2475 * ######## Finalization support
2476 * ######################################################################
2480 * If the object has been forwarded it means it's still referenced from a root.
2481 * If it is pinned it's still alive as well.
2482 * A LOS object is only alive if we have pinned it.
2483 * Return TRUE if @obj is ready to be finalized.
2485 static inline gboolean
2486 sgen_is_object_alive (void *object)
2488 if (ptr_in_nursery (object))
2489 return sgen_nursery_is_object_alive (object);
2491 return sgen_major_is_object_alive (object);
2495 * This function returns true if @object is either alive and belongs to the
2496 * current collection - major collections are full heap, so old gen objects
2497 * are never alive during a minor collection.
2500 sgen_is_object_alive_and_on_current_collection (char *object)
2502 if (ptr_in_nursery (object))
2503 return sgen_nursery_is_object_alive (object);
2505 if (current_collection_generation == GENERATION_NURSERY)
2508 return sgen_major_is_object_alive (object);
2513 sgen_gc_is_object_ready_for_finalization (void *object)
2515 return !sgen_is_object_alive (object);
2519 sgen_queue_finalization_entry (GCObject *obj)
2521 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2523 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2525 sgen_client_object_queued_for_finalization (obj);
2529 sgen_object_is_live (void *obj)
2531 return sgen_is_object_alive_and_on_current_collection (obj);
2535 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2536 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2537 * all finalizers have really finished running.
2539 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2540 * This means that just checking whether the queues are empty leaves the possibility that an
2541 * object might have been dequeued but not yet finalized. That's why we need the additional
2542 * flag `pending_unqueued_finalizer`.
2545 static volatile gboolean pending_unqueued_finalizer = FALSE;
2548 sgen_gc_invoke_finalizers (void)
2552 g_assert (!pending_unqueued_finalizer);
2554 /* FIXME: batch to reduce lock contention */
2555 while (sgen_have_pending_finalizers ()) {
2561 * We need to set `pending_unqueued_finalizer` before dequeing the
2562 * finalizable object.
2564 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2565 pending_unqueued_finalizer = TRUE;
2566 mono_memory_write_barrier ();
2567 obj = sgen_pointer_queue_pop (&fin_ready_queue);
2568 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2569 pending_unqueued_finalizer = TRUE;
2570 mono_memory_write_barrier ();
2571 obj = sgen_pointer_queue_pop (&critical_fin_queue);
2577 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2585 /* the object is on the stack so it is pinned */
2586 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2587 sgen_client_run_finalize (obj);
2590 if (pending_unqueued_finalizer) {
2591 mono_memory_write_barrier ();
2592 pending_unqueued_finalizer = FALSE;
2599 sgen_have_pending_finalizers (void)
2601 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2605 * ######################################################################
2606 * ######## registered roots support
2607 * ######################################################################
2611 * We do not coalesce roots.
2614 sgen_register_root (char *start, size_t size, void *descr, int root_type)
2616 RootRecord new_root;
2619 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2620 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
2621 /* we allow changing the size and the descriptor (for thread statics etc) */
2623 size_t old_size = root->end_root - start;
2624 root->end_root = start + size;
2625 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
2626 ((root->root_desc == 0) && (descr == NULL)));
2627 root->root_desc = (mword)descr;
2629 roots_size -= old_size;
2635 new_root.end_root = start + size;
2636 new_root.root_desc = (mword)descr;
2638 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2641 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);
2648 sgen_deregister_root (char* addr)
2654 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2655 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2656 roots_size -= (root.end_root - addr);
2662 * ######################################################################
2663 * ######## Thread handling (stop/start code)
2664 * ######################################################################
2668 sgen_get_current_collection_generation (void)
2670 return current_collection_generation;
2674 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2676 #ifndef HAVE_KW_THREAD
2677 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2680 sgen_init_tlab_info (info);
2682 sgen_client_thread_register (info, stack_bottom_fallback);
2688 sgen_thread_unregister (SgenThreadInfo *p)
2690 sgen_client_thread_unregister (p);
2695 * ######################################################################
2696 * ######## Write barriers
2697 * ######################################################################
2701 * Note: the write barriers first do the needed GC work and then do the actual store:
2702 * this way the value is visible to the conservative GC scan after the write barrier
2703 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2704 * the conservative scan, otherwise by the remembered set scan.
2708 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2710 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2711 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2712 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2713 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2717 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2718 if (binary_protocol_is_heavy_enabled ()) {
2720 for (i = 0; i < count; ++i) {
2721 gpointer dest = (gpointer*)dest_ptr + i;
2722 gpointer obj = *((gpointer*)src_ptr + i);
2724 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2729 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2733 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2737 HEAVY_STAT (++stat_wbarrier_generic_store);
2739 sgen_client_wbarrier_generic_nostore_check (ptr);
2741 obj = *(gpointer*)ptr;
2743 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2746 * We need to record old->old pointer locations for the
2747 * concurrent collector.
2749 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2750 SGEN_LOG (8, "Skipping remset at %p", ptr);
2754 SGEN_LOG (8, "Adding remset at %p", ptr);
2756 remset.wbarrier_generic_nostore (ptr);
2760 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2762 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2763 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2764 if (ptr_in_nursery (value))
2765 mono_gc_wbarrier_generic_nostore (ptr);
2766 sgen_dummy_use (value);
2769 /* Same as mono_gc_wbarrier_generic_store () but performs the store
2770 * as an atomic operation with release semantics.
2773 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2775 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2777 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2779 InterlockedWritePointer (ptr, value);
2781 if (ptr_in_nursery (value))
2782 mono_gc_wbarrier_generic_nostore (ptr);
2784 sgen_dummy_use (value);
2788 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
2790 GCObject **dest = _dest;
2791 GCObject **src = _src;
2795 mono_gc_wbarrier_generic_store (dest, *src);
2800 size -= SIZEOF_VOID_P;
2806 * ######################################################################
2807 * ######## Other mono public interface functions.
2808 * ######################################################################
2812 sgen_gc_collect (int generation)
2817 sgen_perform_collection (0, generation, "user request", TRUE);
2822 sgen_gc_collection_count (int generation)
2824 if (generation == 0)
2825 return gc_stats.minor_gc_count;
2826 return gc_stats.major_gc_count;
2830 sgen_gc_get_used_size (void)
2834 tot = los_memory_usage;
2835 tot += nursery_section->next_data - nursery_section->data;
2836 tot += major_collector.get_used_size ();
2837 /* FIXME: account for pinned objects */
2843 sgen_weak_link_get (void **link_addr)
2845 void * volatile *link_addr_volatile;
2849 link_addr_volatile = link_addr;
2850 ptr = (void*)*link_addr_volatile;
2852 * At this point we have a hidden pointer. If the GC runs
2853 * here, it will not recognize the hidden pointer as a
2854 * reference, and if the object behind it is not referenced
2855 * elsewhere, it will be freed. Once the world is restarted
2856 * we reveal the pointer, giving us a pointer to a freed
2857 * object. To make sure we don't return it, we load the
2858 * hidden pointer again. If it's still the same, we can be
2859 * sure the object reference is valid.
2862 obj = (GCObject*) REVEAL_POINTER (ptr);
2866 mono_memory_barrier ();
2869 * During the second bridge processing step the world is
2870 * running again. That step processes all weak links once
2871 * more to null those that refer to dead objects. Before that
2872 * is completed, those links must not be followed, so we
2873 * conservatively wait for bridge processing when any weak
2874 * link is dereferenced.
2876 sgen_client_bridge_wait_for_processing ();
2878 if ((void*)*link_addr_volatile != ptr)
2885 sgen_set_allow_synchronous_major (gboolean flag)
2887 if (!major_collector.is_concurrent)
2890 allow_synchronous_major = flag;
2895 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2899 va_start (ap, description_format);
2901 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2902 vfprintf (stderr, description_format, ap);
2904 fprintf (stderr, " - %s", fallback);
2905 fprintf (stderr, "\n");
2911 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2914 double val = strtod (opt, &endptr);
2915 if (endptr == opt) {
2916 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2919 else if (val < min || val > max) {
2920 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
2932 char *major_collector_opt = NULL;
2933 char *minor_collector_opt = NULL;
2934 size_t max_heap = 0;
2935 size_t soft_limit = 0;
2937 gboolean debug_print_allowance = FALSE;
2938 double allowance_ratio = 0, save_target = 0;
2939 gboolean cement_enabled = TRUE;
2942 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
2945 /* already inited */
2948 /* being inited by another thread */
2952 /* we will init it */
2955 g_assert_not_reached ();
2957 } while (result != 0);
2959 SGEN_TV_GETTIME (sgen_init_timestamp);
2961 #ifdef SGEN_WITHOUT_MONO
2962 mono_thread_smr_init ();
2965 LOCK_INIT (gc_mutex);
2967 gc_debug_file = stderr;
2969 LOCK_INIT (sgen_interruption_mutex);
2971 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
2972 opts = g_strsplit (env, ",", -1);
2973 for (ptr = opts; *ptr; ++ptr) {
2975 if (g_str_has_prefix (opt, "major=")) {
2976 opt = strchr (opt, '=') + 1;
2977 major_collector_opt = g_strdup (opt);
2978 } else if (g_str_has_prefix (opt, "minor=")) {
2979 opt = strchr (opt, '=') + 1;
2980 minor_collector_opt = g_strdup (opt);
2988 sgen_init_internal_allocator ();
2989 sgen_init_nursery_allocator ();
2990 sgen_init_fin_weak_hash ();
2991 sgen_init_hash_table ();
2992 sgen_init_descriptors ();
2993 sgen_init_gray_queues ();
2994 sgen_init_allocator ();
2996 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
2997 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
2999 sgen_client_init ();
3001 if (!minor_collector_opt) {
3002 sgen_simple_nursery_init (&sgen_minor_collector);
3004 if (!strcmp (minor_collector_opt, "simple")) {
3006 sgen_simple_nursery_init (&sgen_minor_collector);
3007 } else if (!strcmp (minor_collector_opt, "split")) {
3008 sgen_split_nursery_init (&sgen_minor_collector);
3010 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
3011 goto use_simple_nursery;
3015 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
3016 use_marksweep_major:
3017 sgen_marksweep_init (&major_collector);
3018 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
3019 sgen_marksweep_conc_init (&major_collector);
3021 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
3022 goto use_marksweep_major;
3025 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
3027 if (major_collector.is_concurrent)
3028 cement_enabled = FALSE;
3031 gboolean usage_printed = FALSE;
3033 for (ptr = opts; *ptr; ++ptr) {
3035 if (!strcmp (opt, ""))
3037 if (g_str_has_prefix (opt, "major="))
3039 if (g_str_has_prefix (opt, "minor="))
3041 if (g_str_has_prefix (opt, "max-heap-size=")) {
3042 size_t page_size = mono_pagesize ();
3043 size_t max_heap_candidate = 0;
3044 opt = strchr (opt, '=') + 1;
3045 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
3046 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
3047 if (max_heap != max_heap_candidate)
3048 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
3050 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
3054 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
3055 opt = strchr (opt, '=') + 1;
3056 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
3057 if (soft_limit <= 0) {
3058 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
3062 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
3068 if (g_str_has_prefix (opt, "nursery-size=")) {
3070 opt = strchr (opt, '=') + 1;
3071 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
3072 if ((val & (val - 1))) {
3073 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
3077 if (val < SGEN_MAX_NURSERY_WASTE) {
3078 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3079 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
3083 sgen_nursery_size = val;
3084 sgen_nursery_bits = 0;
3085 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
3088 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
3094 if (g_str_has_prefix (opt, "save-target-ratio=")) {
3096 opt = strchr (opt, '=') + 1;
3097 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
3098 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
3103 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
3105 opt = strchr (opt, '=') + 1;
3106 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
3107 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3108 allowance_ratio = val;
3112 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
3113 if (!major_collector.is_concurrent) {
3114 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
3118 opt = strchr (opt, '=') + 1;
3120 if (!strcmp (opt, "yes")) {
3121 allow_synchronous_major = TRUE;
3122 } else if (!strcmp (opt, "no")) {
3123 allow_synchronous_major = FALSE;
3125 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
3130 if (!strcmp (opt, "cementing")) {
3131 cement_enabled = TRUE;
3134 if (!strcmp (opt, "no-cementing")) {
3135 cement_enabled = FALSE;
3139 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3142 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3145 if (sgen_client_handle_gc_param (opt))
3148 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3153 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3154 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3155 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3156 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3157 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3158 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3159 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3160 fprintf (stderr, " [no-]cementing\n");
3161 if (major_collector.is_concurrent)
3162 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
3163 if (major_collector.print_gc_param_usage)
3164 major_collector.print_gc_param_usage ();
3165 if (sgen_minor_collector.print_gc_param_usage)
3166 sgen_minor_collector.print_gc_param_usage ();
3167 sgen_client_print_gc_params_usage ();
3168 fprintf (stderr, " Experimental options:\n");
3169 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3170 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);
3171 fprintf (stderr, "\n");
3173 usage_printed = TRUE;
3178 if (major_collector_opt)
3179 g_free (major_collector_opt);
3181 if (minor_collector_opt)
3182 g_free (minor_collector_opt);
3186 if (major_collector.is_concurrent && cement_enabled) {
3187 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported on concurrent major collectors.");
3188 cement_enabled = FALSE;
3191 sgen_cement_init (cement_enabled);
3193 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
3194 gboolean usage_printed = FALSE;
3196 opts = g_strsplit (env, ",", -1);
3197 for (ptr = opts; ptr && *ptr; ptr ++) {
3199 if (!strcmp (opt, ""))
3201 if (opt [0] >= '0' && opt [0] <= '9') {
3202 gc_debug_level = atoi (opt);
3207 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3208 gc_debug_file = fopen (rf, "wb");
3210 gc_debug_file = stderr;
3213 } else if (!strcmp (opt, "print-allowance")) {
3214 debug_print_allowance = TRUE;
3215 } else if (!strcmp (opt, "print-pinning")) {
3216 sgen_pin_stats_enable ();
3217 } else if (!strcmp (opt, "verify-before-allocs")) {
3218 verify_before_allocs = 1;
3219 has_per_allocation_action = TRUE;
3220 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3221 char *arg = strchr (opt, '=') + 1;
3222 verify_before_allocs = atoi (arg);
3223 has_per_allocation_action = TRUE;
3224 } else if (!strcmp (opt, "collect-before-allocs")) {
3225 collect_before_allocs = 1;
3226 has_per_allocation_action = TRUE;
3227 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3228 char *arg = strchr (opt, '=') + 1;
3229 has_per_allocation_action = TRUE;
3230 collect_before_allocs = atoi (arg);
3231 } else if (!strcmp (opt, "verify-before-collections")) {
3232 whole_heap_check_before_collection = TRUE;
3233 } else if (!strcmp (opt, "check-at-minor-collections")) {
3234 consistency_check_at_minor_collection = TRUE;
3235 nursery_clear_policy = CLEAR_AT_GC;
3236 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3237 if (!major_collector.is_concurrent) {
3238 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3241 mod_union_consistency_check = TRUE;
3242 } else if (!strcmp (opt, "check-mark-bits")) {
3243 check_mark_bits_after_major_collection = TRUE;
3244 } else if (!strcmp (opt, "check-nursery-pinned")) {
3245 check_nursery_objects_pinned = TRUE;
3246 } else if (!strcmp (opt, "clear-at-gc")) {
3247 nursery_clear_policy = CLEAR_AT_GC;
3248 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3249 nursery_clear_policy = CLEAR_AT_GC;
3250 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3251 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3252 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3253 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3254 } else if (!strcmp (opt, "check-scan-starts")) {
3255 do_scan_starts_check = TRUE;
3256 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3257 do_verify_nursery = TRUE;
3258 } else if (!strcmp (opt, "check-concurrent")) {
3259 if (!major_collector.is_concurrent) {
3260 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3263 do_concurrent_checks = TRUE;
3264 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3265 do_dump_nursery_content = TRUE;
3266 } else if (!strcmp (opt, "disable-minor")) {
3267 disable_minor_collections = TRUE;
3268 } else if (!strcmp (opt, "disable-major")) {
3269 disable_major_collections = TRUE;
3270 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3271 char *filename = strchr (opt, '=') + 1;
3272 nursery_clear_policy = CLEAR_AT_GC;
3273 sgen_debug_enable_heap_dump (filename);
3274 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3275 char *filename = strchr (opt, '=') + 1;
3276 char *colon = strrchr (filename, ':');
3279 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3280 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3285 binary_protocol_init (filename, (long long)limit);
3286 } else if (!strcmp (opt, "nursery-canaries")) {
3287 do_verify_nursery = TRUE;
3288 enable_nursery_canaries = TRUE;
3289 } else if (!sgen_client_handle_gc_debug (opt)) {
3290 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3295 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);
3296 fprintf (stderr, "Valid <option>s are:\n");
3297 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3298 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3299 fprintf (stderr, " check-at-minor-collections\n");
3300 fprintf (stderr, " check-mark-bits\n");
3301 fprintf (stderr, " check-nursery-pinned\n");
3302 fprintf (stderr, " verify-before-collections\n");
3303 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3304 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3305 fprintf (stderr, " disable-minor\n");
3306 fprintf (stderr, " disable-major\n");
3307 fprintf (stderr, " check-concurrent\n");
3308 fprintf (stderr, " clear-[nursery-]at-gc\n");
3309 fprintf (stderr, " clear-at-tlab-creation\n");
3310 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3311 fprintf (stderr, " check-scan-starts\n");
3312 fprintf (stderr, " print-allowance\n");
3313 fprintf (stderr, " print-pinning\n");
3314 fprintf (stderr, " heap-dump=<filename>\n");
3315 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3316 fprintf (stderr, " nursery-canaries\n");
3317 sgen_client_print_gc_debug_usage ();
3318 fprintf (stderr, "\n");
3320 usage_printed = TRUE;
3326 if (check_mark_bits_after_major_collection)
3327 nursery_clear_policy = CLEAR_AT_GC;
3329 if (major_collector.post_param_init)
3330 major_collector.post_param_init (&major_collector);
3332 if (major_collector.needs_thread_pool)
3333 sgen_workers_init (1);
3335 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3337 memset (&remset, 0, sizeof (remset));
3339 sgen_card_table_init (&remset);
3345 sgen_get_nursery_clear_policy (void)
3347 return nursery_clear_policy;
3357 sgen_gc_unlock (void)
3359 gboolean try_free = sgen_try_free_some_memory;
3360 sgen_try_free_some_memory = FALSE;
3361 mono_mutex_unlock (&gc_mutex);
3363 mono_thread_hazardous_try_free_some ();
3367 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3369 major_collector.iterate_live_block_ranges (callback);
3373 sgen_get_major_collector (void)
3375 return &major_collector;
3379 sgen_get_remset (void)
3385 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3387 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3388 sgen_los_count_cards (los_total, los_marked);
3391 static gboolean world_is_stopped = FALSE;
3393 /* LOCKING: assumes the GC lock is held */
3395 sgen_stop_world (int generation)
3397 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3399 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3401 binary_protocol_world_stopping (generation, sgen_timestamp ());
3403 sgen_client_stop_world (generation);
3405 world_is_stopped = TRUE;
3407 if (binary_protocol_is_heavy_enabled ())
3408 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3409 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3412 /* LOCKING: assumes the GC lock is held */
3414 sgen_restart_world (int generation, GGTimingInfo *timing)
3416 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3418 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3420 if (binary_protocol_is_heavy_enabled ())
3421 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3422 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3424 sgen_client_restart_world (generation, timing);
3426 world_is_stopped = FALSE;
3428 binary_protocol_world_restarted (generation, sgen_timestamp ());
3430 sgen_try_free_some_memory = TRUE;
3432 if (sgen_client_bridge_need_processing ())
3433 sgen_client_bridge_processing_finish (generation);
3435 sgen_memgov_collection_end (generation, timing, timing ? 2 : 0);
3439 sgen_is_world_stopped (void)
3441 return world_is_stopped;
3445 sgen_check_whole_heap_stw (void)
3447 sgen_stop_world (0);
3448 sgen_clear_nursery_fragments ();
3449 sgen_check_whole_heap (FALSE);
3450 sgen_restart_world (0, NULL);
3454 sgen_timestamp (void)
3456 SGEN_TV_DECLARE (timestamp);
3457 SGEN_TV_GETTIME (timestamp);
3458 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3461 #endif /* HAVE_SGEN_GC */