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_field = 0;
275 static guint64 stat_wbarrier_set_arrayref = 0;
276 static guint64 stat_wbarrier_arrayref_copy = 0;
277 static guint64 stat_wbarrier_generic_store = 0;
278 static guint64 stat_wbarrier_generic_store_atomic = 0;
279 static guint64 stat_wbarrier_set_root = 0;
280 static guint64 stat_wbarrier_value_copy = 0;
281 static guint64 stat_wbarrier_object_copy = 0;
284 static guint64 stat_pinned_objects = 0;
286 static guint64 time_minor_pre_collection_fragment_clear = 0;
287 static guint64 time_minor_pinning = 0;
288 static guint64 time_minor_scan_remsets = 0;
289 static guint64 time_minor_scan_pinned = 0;
290 static guint64 time_minor_scan_roots = 0;
291 static guint64 time_minor_finish_gray_stack = 0;
292 static guint64 time_minor_fragment_creation = 0;
294 static guint64 time_major_pre_collection_fragment_clear = 0;
295 static guint64 time_major_pinning = 0;
296 static guint64 time_major_scan_pinned = 0;
297 static guint64 time_major_scan_roots = 0;
298 static guint64 time_major_scan_mod_union = 0;
299 static guint64 time_major_finish_gray_stack = 0;
300 static guint64 time_major_free_bigobjs = 0;
301 static guint64 time_major_los_sweep = 0;
302 static guint64 time_major_sweep = 0;
303 static guint64 time_major_fragment_creation = 0;
305 static guint64 time_max = 0;
307 static SGEN_TV_DECLARE (time_major_conc_collection_start);
308 static SGEN_TV_DECLARE (time_major_conc_collection_end);
310 static SGEN_TV_DECLARE (last_minor_collection_start_tv);
311 static SGEN_TV_DECLARE (last_minor_collection_end_tv);
313 int gc_debug_level = 0;
318 mono_gc_flush_info (void)
320 fflush (gc_debug_file);
324 #define TV_DECLARE SGEN_TV_DECLARE
325 #define TV_GETTIME SGEN_TV_GETTIME
326 #define TV_ELAPSED SGEN_TV_ELAPSED
328 SGEN_TV_DECLARE (sgen_init_timestamp);
330 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
332 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
333 #define object_is_pinned SGEN_OBJECT_IS_PINNED
334 #define pin_object SGEN_PIN_OBJECT
336 #define ptr_in_nursery sgen_ptr_in_nursery
338 #define LOAD_VTABLE SGEN_LOAD_VTABLE
341 nursery_canaries_enabled (void)
343 return enable_nursery_canaries;
346 #define safe_object_get_size sgen_safe_object_get_size
349 * ######################################################################
350 * ######## Global data.
351 * ######################################################################
353 LOCK_DECLARE (gc_mutex);
354 gboolean sgen_try_free_some_memory;
356 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
358 size_t degraded_mode = 0;
360 static mword bytes_pinned_from_failed_allocation = 0;
362 GCMemSection *nursery_section = NULL;
363 static volatile mword lowest_heap_address = ~(mword)0;
364 static volatile mword highest_heap_address = 0;
366 LOCK_DECLARE (sgen_interruption_mutex);
368 int current_collection_generation = -1;
369 volatile gboolean concurrent_collection_in_progress = FALSE;
371 /* objects that are ready to be finalized */
372 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
373 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
375 /* registered roots: the key to the hash is the root start address */
377 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
379 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
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),
382 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
384 static mword roots_size = 0; /* amount of memory in the root set */
386 /* The size of a TLAB */
387 /* The bigger the value, the less often we have to go to the slow path to allocate a new
388 * one, but the more space is wasted by threads not allocating much memory.
390 * FIXME: Make this self-tuning for each thread.
392 guint32 tlab_size = (1024 * 4);
394 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
396 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
398 #define ALIGN_UP SGEN_ALIGN_UP
400 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
401 MonoNativeThreadId main_gc_thread = NULL;
404 /*Object was pinned during the current collection*/
405 static mword objects_pinned;
408 * ######################################################################
409 * ######## Macros and function declarations.
410 * ######################################################################
413 typedef SgenGrayQueue GrayQueue;
415 /* forward declarations */
416 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
418 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
419 static void finish_gray_stack (int generation, ScanCopyContext ctx);
422 SgenMajorCollector major_collector;
423 SgenMinorCollector sgen_minor_collector;
424 /* FIXME: get rid of this */
425 static GrayQueue gray_queue;
427 static SgenRememberedSet remset;
429 /* The gray queue to use from the main collection thread. */
430 #define WORKERS_DISTRIBUTE_GRAY_QUEUE (&gray_queue)
433 * The gray queue a worker job must use. If we're not parallel or
434 * concurrent, we use the main gray queue.
436 static SgenGrayQueue*
437 sgen_workers_get_job_gray_queue (WorkerData *worker_data)
439 return worker_data ? &worker_data->private_gray_queue : WORKERS_DISTRIBUTE_GRAY_QUEUE;
443 gray_queue_redirect (SgenGrayQueue *queue)
445 gboolean wake = FALSE;
448 GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
451 sgen_section_gray_queue_enqueue (queue->alloc_prepare_data, section);
456 g_assert (concurrent_collection_in_progress);
457 sgen_workers_ensure_awake ();
462 gray_queue_enable_redirect (SgenGrayQueue *queue)
464 if (!concurrent_collection_in_progress)
467 sgen_gray_queue_set_alloc_prepare (queue, gray_queue_redirect, sgen_workers_get_distribute_section_gray_queue ());
468 gray_queue_redirect (queue);
472 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags)
474 while (start < end) {
478 if (!*(void**)start) {
479 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
484 if (!(obj = SGEN_OBJECT_IS_FORWARDED (start)))
490 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
491 CHECK_CANARY_FOR_OBJECT (obj);
492 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
493 callback (obj, size, data);
494 CANARIFY_SIZE (size);
496 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
504 * sgen_add_to_global_remset:
506 * The global remset contains locations which point into newspace after
507 * a minor collection. This can happen if the objects they point to are pinned.
509 * LOCKING: If called from a parallel collector, the global remset
510 * lock must be held. For serial collectors that is not necessary.
513 sgen_add_to_global_remset (gpointer ptr, gpointer obj)
515 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
517 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
519 if (!major_collector.is_concurrent) {
520 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
522 if (current_collection_generation == -1)
523 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
526 if (!object_is_pinned (obj))
527 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");
528 else if (sgen_cement_lookup_or_register (obj))
531 remset.record_pointer (ptr);
533 sgen_pin_stats_register_global_remset (obj);
535 SGEN_LOG (8, "Adding global remset for %p", ptr);
536 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
540 * sgen_drain_gray_stack:
542 * Scan objects in the gray stack until the stack is empty. This should be called
543 * frequently after each object is copied, to achieve better locality and cache
546 * max_objs is the maximum number of objects to scan, or -1 to scan until the stack is
550 sgen_drain_gray_stack (int max_objs, ScanCopyContext ctx)
552 ScanObjectFunc scan_func = ctx.ops->scan_object;
553 GrayQueue *queue = ctx.queue;
555 if (current_collection_generation == GENERATION_OLD && major_collector.drain_gray_stack)
556 return major_collector.drain_gray_stack (ctx);
560 for (i = 0; i != max_objs; ++i) {
563 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
566 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
567 scan_func (obj, desc, queue);
569 } while (max_objs < 0);
574 * Addresses in the pin queue are already sorted. This function finds
575 * the object header for each address and pins the object. The
576 * addresses must be inside the nursery section. The (start of the)
577 * address array is overwritten with the addresses of the actually
578 * pinned objects. Return the number of pinned objects.
581 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
583 GCMemSection *section = nursery_section;
584 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
585 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
586 void *start_nursery = section->data;
587 void *end_nursery = section->next_data;
592 void *pinning_front = start_nursery;
594 void **definitely_pinned = start;
595 ScanObjectFunc scan_func = ctx.ops->scan_object;
596 SgenGrayQueue *queue = ctx.queue;
598 sgen_nursery_allocator_prepare_for_pinning ();
600 while (start < end) {
601 void *obj_to_pin = NULL;
602 size_t obj_to_pin_size = 0;
607 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
608 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
615 SGEN_LOG (5, "Considering pinning addr %p", addr);
616 /* We've already processed everything up to pinning_front. */
617 if (addr < pinning_front) {
623 * Find the closest scan start <= addr. We might search backward in the
624 * scan_starts array because entries might be NULL. In the worst case we
625 * start at start_nursery.
627 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
628 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
629 search_start = (void*)section->scan_starts [idx];
630 if (!search_start || search_start > addr) {
633 search_start = section->scan_starts [idx];
634 if (search_start && search_start <= addr)
637 if (!search_start || search_start > addr)
638 search_start = start_nursery;
642 * If the pinning front is closer than the scan start we found, start
643 * searching at the front.
645 if (search_start < pinning_front)
646 search_start = pinning_front;
649 * Now addr should be in an object a short distance from search_start.
651 * search_start must point to zeroed mem or point to an object.
654 size_t obj_size, canarified_obj_size;
657 if (!*(void**)search_start) {
658 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
659 /* The loop condition makes sure we don't overrun addr. */
663 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
666 * Filler arrays are marked by an invalid sync word. We don't
667 * consider them for pinning. They are not delimited by canaries,
670 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
671 CHECK_CANARY_FOR_OBJECT (search_start);
672 CANARIFY_SIZE (canarified_obj_size);
674 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
675 /* This is the object we're looking for. */
676 obj_to_pin = search_start;
677 obj_to_pin_size = canarified_obj_size;
682 /* Skip to the next object */
683 search_start = (void*)((char*)search_start + canarified_obj_size);
684 } while (search_start <= addr);
686 /* We've searched past the address we were looking for. */
688 pinning_front = search_start;
689 goto next_pin_queue_entry;
693 * We've found an object to pin. It might still be a dummy array, but we
694 * can advance the pinning front in any case.
696 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
699 * If this is a dummy array marking the beginning of a nursery
700 * fragment, we don't pin it.
702 if (sgen_client_object_is_array_fill ((GCObject*)obj_to_pin))
703 goto next_pin_queue_entry;
706 * Finally - pin the object!
708 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
709 if (do_scan_objects) {
710 scan_func (obj_to_pin, desc, queue);
712 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
713 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
714 binary_protocol_pin (obj_to_pin,
715 (gpointer)LOAD_VTABLE (obj_to_pin),
716 safe_object_get_size (obj_to_pin));
718 pin_object (obj_to_pin);
719 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
720 sgen_pin_stats_register_object (obj_to_pin, obj_to_pin_size);
721 definitely_pinned [count] = obj_to_pin;
725 next_pin_queue_entry:
729 sgen_client_nursery_objects_pinned (definitely_pinned, count);
730 stat_pinned_objects += count;
735 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
739 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
742 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
743 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
747 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
748 * when we can't promote an object because we're out of memory.
751 sgen_pin_object (void *object, GrayQueue *queue)
754 * All pinned objects are assumed to have been staged, so we need to stage as well.
755 * Also, the count of staged objects shows that "late pinning" happened.
757 sgen_pin_stage_ptr (object);
759 SGEN_PIN_OBJECT (object);
760 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
763 sgen_pin_stats_register_object (object, safe_object_get_size (object));
765 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
768 /* Sort the addresses in array in increasing order.
769 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
772 sgen_sort_addresses (void **array, size_t size)
777 for (i = 1; i < size; ++i) {
780 size_t parent = (child - 1) / 2;
782 if (array [parent] >= array [child])
785 tmp = array [parent];
786 array [parent] = array [child];
793 for (i = size - 1; i > 0; --i) {
796 array [i] = array [0];
802 while (root * 2 + 1 <= end) {
803 size_t child = root * 2 + 1;
805 if (child < end && array [child] < array [child + 1])
807 if (array [root] >= array [child])
811 array [root] = array [child];
820 * Scan the memory between start and end and queue values which could be pointers
821 * to the area between start_nursery and end_nursery for later consideration.
822 * Typically used for thread stacks.
825 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
829 #ifdef VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE
830 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
833 while (start < end) {
834 if (*start >= start_nursery && *start < end_nursery) {
836 * *start can point to the middle of an object
837 * note: should we handle pointing at the end of an object?
838 * pinning in C# code disallows pointing at the end of an object
839 * but there is some small chance that an optimizing C compiler
840 * may keep the only reference to an object by pointing
841 * at the end of it. We ignore this small chance for now.
842 * Pointers to the end of an object are indistinguishable
843 * from pointers to the start of the next object in memory
844 * so if we allow that we'd need to pin two objects...
845 * We queue the pointer in an array, the
846 * array will then be sorted and uniqued. This way
847 * we can coalesce several pinning pointers and it should
848 * be faster since we'd do a memory scan with increasing
849 * addresses. Note: we can align the address to the allocation
850 * alignment, so the unique process is more effective.
852 mword addr = (mword)*start;
853 addr &= ~(ALLOC_ALIGN - 1);
854 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
855 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
856 sgen_pin_stage_ptr ((void*)addr);
857 binary_protocol_pin_stage (start, (void*)addr);
862 * FIXME: It seems we're registering objects from all over the heap
863 * (at least from the nursery and the LOS), but we're only
864 * registering pinned addresses in the nursery. What's up with
867 * Also, why wouldn't we register addresses once the pinning queue
868 * is sorted and uniqued?
870 if (ptr_in_nursery ((void*)addr))
871 sgen_pin_stats_register_address ((char*)addr, pin_type);
876 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
880 * The first thing we do in a collection is to identify pinned objects.
881 * This function considers all the areas of memory that need to be
882 * conservatively scanned.
885 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
889 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);
890 /* objects pinned from the API are inside these roots */
891 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], start_root, root) {
892 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
893 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
894 } SGEN_HASH_TABLE_FOREACH_END;
895 /* now deal with the thread stacks
896 * in the future we should be able to conservatively scan only:
897 * *) the cpu registers
898 * *) the unmanaged stack frames
899 * *) the _last_ managed stack frame
900 * *) pointers slots in managed frames
902 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
906 unpin_objects_from_queue (SgenGrayQueue *queue)
911 GRAY_OBJECT_DEQUEUE (queue, &addr, &desc);
914 g_assert (SGEN_OBJECT_IS_PINNED (addr));
915 SGEN_UNPIN_OBJECT (addr);
920 single_arg_user_copy_or_mark (void **obj, void *gc_data)
922 ScanCopyContext *ctx = gc_data;
923 ctx->ops->copy_or_mark_object (obj, ctx->queue);
927 * The memory area from start_root to end_root contains pointers to objects.
928 * Their position is precisely described by @desc (this means that the pointer
929 * can be either NULL or the pointer to the start of an object).
930 * This functions copies them to to_space updates them.
932 * This function is not thread-safe!
935 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, mword desc, ScanCopyContext ctx)
937 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
938 SgenGrayQueue *queue = ctx.queue;
940 switch (desc & ROOT_DESC_TYPE_MASK) {
941 case ROOT_DESC_BITMAP:
942 desc >>= ROOT_DESC_TYPE_SHIFT;
944 if ((desc & 1) && *start_root) {
945 copy_func (start_root, queue);
946 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
952 case ROOT_DESC_COMPLEX: {
953 gsize *bitmap_data = sgen_get_complex_descriptor_bitmap (desc);
954 gsize bwords = (*bitmap_data) - 1;
955 void **start_run = start_root;
957 while (bwords-- > 0) {
958 gsize bmap = *bitmap_data++;
959 void **objptr = start_run;
961 if ((bmap & 1) && *objptr) {
962 copy_func (objptr, queue);
963 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
968 start_run += GC_BITS_PER_WORD;
972 case ROOT_DESC_USER: {
973 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
974 marker (start_root, single_arg_user_copy_or_mark, &ctx);
977 case ROOT_DESC_RUN_LEN:
978 g_assert_not_reached ();
980 g_assert_not_reached ();
985 reset_heap_boundaries (void)
987 lowest_heap_address = ~(mword)0;
988 highest_heap_address = 0;
992 sgen_update_heap_boundaries (mword low, mword high)
997 old = lowest_heap_address;
1000 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
1003 old = highest_heap_address;
1006 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
1010 * Allocate and setup the data structures needed to be able to allocate objects
1011 * in the nursery. The nursery is stored in nursery_section.
1014 alloc_nursery (void)
1016 GCMemSection *section;
1021 if (nursery_section)
1023 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
1024 /* later we will alloc a larger area for the nursery but only activate
1025 * what we need. The rest will be used as expansion if we have too many pinned
1026 * objects in the existing nursery.
1028 /* FIXME: handle OOM */
1029 section = sgen_alloc_internal (INTERNAL_MEM_SECTION);
1031 alloc_size = sgen_nursery_size;
1033 /* If there isn't enough space even for the nursery we should simply abort. */
1034 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
1036 data = major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
1037 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
1038 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 ());
1039 section->data = section->next_data = data;
1040 section->size = alloc_size;
1041 section->end_data = data + sgen_nursery_size;
1042 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1043 section->scan_starts = sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1044 section->num_scan_start = scan_starts;
1046 nursery_section = section;
1048 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
1052 mono_gc_get_logfile (void)
1054 return gc_debug_file;
1058 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1060 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1061 SgenGrayQueue *queue = ctx.queue;
1064 for (i = 0; i < fin_queue->next_slot; ++i) {
1065 void *obj = fin_queue->data [i];
1068 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1069 copy_func (&fin_queue->data [i], queue);
1074 generation_name (int generation)
1076 switch (generation) {
1077 case GENERATION_NURSERY: return "nursery";
1078 case GENERATION_OLD: return "old";
1079 default: g_assert_not_reached ();
1084 sgen_generation_name (int generation)
1086 return generation_name (generation);
1090 finish_gray_stack (int generation, ScanCopyContext ctx)
1094 int done_with_ephemerons, ephemeron_rounds = 0;
1095 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1096 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1097 SgenGrayQueue *queue = ctx.queue;
1100 * We copied all the reachable objects. Now it's the time to copy
1101 * the objects that were not referenced by the roots, but by the copied objects.
1102 * we built a stack of objects pointed to by gray_start: they are
1103 * additional roots and we may add more items as we go.
1104 * We loop until gray_start == gray_objects which means no more objects have
1105 * been added. Note this is iterative: no recursion is involved.
1106 * We need to walk the LO list as well in search of marked big objects
1107 * (use a flag since this is needed only on major collections). We need to loop
1108 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1109 * To achieve better cache locality and cache usage, we drain the gray stack
1110 * frequently, after each object is copied, and just finish the work here.
1112 sgen_drain_gray_stack (-1, ctx);
1114 SGEN_LOG (2, "%s generation done", generation_name (generation));
1117 Reset bridge data, we might have lingering data from a previous collection if this is a major
1118 collection trigged by minor overflow.
1120 We must reset the gathered bridges since their original block might be evacuated due to major
1121 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1123 if (sgen_client_bridge_need_processing ())
1124 sgen_client_bridge_reset_data ();
1127 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1128 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1129 * objects that are in fact reachable.
1131 done_with_ephemerons = 0;
1133 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1134 sgen_drain_gray_stack (-1, ctx);
1136 } while (!done_with_ephemerons);
1138 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1140 if (sgen_client_bridge_need_processing ()) {
1141 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1142 sgen_drain_gray_stack (-1, ctx);
1143 sgen_collect_bridge_objects (generation, ctx);
1144 if (generation == GENERATION_OLD)
1145 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1148 Do the first bridge step here, as the collector liveness state will become useless after that.
1150 An important optimization is to only proccess the possibly dead part of the object graph and skip
1151 over all live objects as we transitively know everything they point must be alive too.
1153 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1155 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1156 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1159 sgen_client_bridge_processing_stw_step ();
1163 Make sure we drain the gray stack before processing disappearing links and finalizers.
1164 If we don't make sure it is empty we might wrongly see a live object as dead.
1166 sgen_drain_gray_stack (-1, ctx);
1169 We must clear weak links that don't track resurrection before processing object ready for
1170 finalization so they can be cleared before that.
1172 sgen_null_link_in_range (generation, TRUE, ctx);
1173 if (generation == GENERATION_OLD)
1174 sgen_null_link_in_range (GENERATION_NURSERY, TRUE, ctx);
1177 /* walk the finalization queue and move also the objects that need to be
1178 * finalized: use the finalized objects as new roots so the objects they depend
1179 * on are also not reclaimed. As with the roots above, only objects in the nursery
1180 * are marked/copied.
1182 sgen_finalize_in_range (generation, ctx);
1183 if (generation == GENERATION_OLD)
1184 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1185 /* drain the new stack that might have been created */
1186 SGEN_LOG (6, "Precise scan of gray area post fin");
1187 sgen_drain_gray_stack (-1, ctx);
1190 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1192 done_with_ephemerons = 0;
1194 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1195 sgen_drain_gray_stack (-1, ctx);
1197 } while (!done_with_ephemerons);
1199 sgen_client_clear_unreachable_ephemerons (ctx);
1202 * We clear togglerefs only after all possible chances of revival are done.
1203 * This is semantically more inline with what users expect and it allows for
1204 * user finalizers to correctly interact with TR objects.
1206 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1209 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %d usecs %d ephemeron rounds", generation_name (generation), TV_ELAPSED (atv, btv), ephemeron_rounds);
1212 * handle disappearing links
1213 * Note we do this after checking the finalization queue because if an object
1214 * survives (at least long enough to be finalized) we don't clear the link.
1215 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1216 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1219 g_assert (sgen_gray_object_queue_is_empty (queue));
1221 sgen_null_link_in_range (generation, FALSE, ctx);
1222 if (generation == GENERATION_OLD)
1223 sgen_null_link_in_range (GENERATION_NURSERY, FALSE, ctx);
1224 if (sgen_gray_object_queue_is_empty (queue))
1226 sgen_drain_gray_stack (-1, ctx);
1229 g_assert (sgen_gray_object_queue_is_empty (queue));
1231 sgen_gray_object_queue_trim_free_list (queue);
1235 sgen_check_section_scan_starts (GCMemSection *section)
1238 for (i = 0; i < section->num_scan_start; ++i) {
1239 if (section->scan_starts [i]) {
1240 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1241 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1247 check_scan_starts (void)
1249 if (!do_scan_starts_check)
1251 sgen_check_section_scan_starts (nursery_section);
1252 major_collector.check_scan_starts ();
1256 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1260 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], start_root, root) {
1261 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1262 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1263 } SGEN_HASH_TABLE_FOREACH_END;
1269 static gboolean inited = FALSE;
1274 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1276 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1277 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1278 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1279 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1280 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1281 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1283 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1284 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1285 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1286 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1287 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1288 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1289 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1290 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1291 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1292 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1294 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1296 #ifdef HEAVY_STATISTICS
1297 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1298 mono_counters_register ("WBarrier set field", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_field);
1299 mono_counters_register ("WBarrier set arrayref", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_arrayref);
1300 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1301 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1302 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1303 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1304 mono_counters_register ("WBarrier value copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_value_copy);
1305 mono_counters_register ("WBarrier object copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_object_copy);
1307 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1308 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1310 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1311 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1312 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1313 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1315 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1316 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1318 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1320 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1321 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1322 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1323 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1325 sgen_nursery_allocator_init_heavy_stats ();
1333 reset_pinned_from_failed_allocation (void)
1335 bytes_pinned_from_failed_allocation = 0;
1339 sgen_set_pinned_from_failed_allocation (mword objsize)
1341 bytes_pinned_from_failed_allocation += objsize;
1345 sgen_collection_is_concurrent (void)
1347 switch (current_collection_generation) {
1348 case GENERATION_NURSERY:
1350 case GENERATION_OLD:
1351 return concurrent_collection_in_progress;
1353 g_error ("Invalid current generation %d", current_collection_generation);
1359 sgen_concurrent_collection_in_progress (void)
1361 return concurrent_collection_in_progress;
1365 SgenThreadPoolJob job;
1366 SgenObjectOperations *ops;
1370 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
1372 WorkerData *worker_data = worker_data_untyped;
1373 ScanJob *job_data = (ScanJob*)job;
1374 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1375 remset.scan_remsets (ctx);
1379 SgenThreadPoolJob job;
1380 SgenObjectOperations *ops;
1384 } ScanFromRegisteredRootsJob;
1387 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1389 WorkerData *worker_data = worker_data_untyped;
1390 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1391 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1393 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1397 SgenThreadPoolJob job;
1398 SgenObjectOperations *ops;
1401 } ScanThreadDataJob;
1404 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1406 WorkerData *worker_data = worker_data_untyped;
1407 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1408 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1410 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1414 SgenThreadPoolJob job;
1415 SgenObjectOperations *ops;
1416 SgenPointerQueue *queue;
1417 } ScanFinalizerEntriesJob;
1420 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1422 WorkerData *worker_data = worker_data_untyped;
1423 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1424 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1426 scan_finalizer_entries (job_data->queue, ctx);
1430 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1432 WorkerData *worker_data = worker_data_untyped;
1433 ScanJob *job_data = (ScanJob*)job;
1434 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1436 g_assert (concurrent_collection_in_progress);
1437 major_collector.scan_card_table (TRUE, ctx);
1441 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1443 WorkerData *worker_data = worker_data_untyped;
1444 ScanJob *job_data = (ScanJob*)job;
1445 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (job_data->ops, sgen_workers_get_job_gray_queue (worker_data));
1447 g_assert (concurrent_collection_in_progress);
1448 sgen_los_scan_card_table (TRUE, ctx);
1452 init_gray_queue (void)
1454 if (sgen_collection_is_concurrent ())
1455 sgen_workers_init_distribute_gray_queue ();
1456 sgen_gray_object_queue_init (&gray_queue, NULL);
1460 enqueue_scan_from_roots_jobs (char *heap_start, char *heap_end, SgenObjectOperations *ops)
1462 ScanFromRegisteredRootsJob *scrrj;
1463 ScanThreadDataJob *stdj;
1464 ScanFinalizerEntriesJob *sfej;
1466 /* registered roots, this includes static fields */
1468 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1470 scrrj->heap_start = heap_start;
1471 scrrj->heap_end = heap_end;
1472 scrrj->root_type = ROOT_TYPE_NORMAL;
1473 sgen_workers_enqueue_job (&scrrj->job);
1475 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1477 scrrj->heap_start = heap_start;
1478 scrrj->heap_end = heap_end;
1479 scrrj->root_type = ROOT_TYPE_WBARRIER;
1480 sgen_workers_enqueue_job (&scrrj->job);
1484 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1485 stdj->heap_start = heap_start;
1486 stdj->heap_end = heap_end;
1487 sgen_workers_enqueue_job (&stdj->job);
1489 /* Scan the list of objects ready for finalization. */
1491 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1492 sfej->queue = &fin_ready_queue;
1494 sgen_workers_enqueue_job (&sfej->job);
1496 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1497 sfej->queue = &critical_fin_queue;
1499 sgen_workers_enqueue_job (&sfej->job);
1503 * Perform a nursery collection.
1505 * Return whether any objects were late-pinned due to being out of memory.
1508 collect_nursery (SgenGrayQueue *unpin_queue, gboolean finish_up_concurrent_mark)
1510 gboolean needs_major;
1511 size_t max_garbage_amount;
1513 mword fragment_total;
1515 SgenObjectOperations *object_ops = &sgen_minor_collector.serial_ops;
1516 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gray_queue);
1520 if (disable_minor_collections)
1523 TV_GETTIME (last_minor_collection_start_tv);
1524 atv = last_minor_collection_start_tv;
1526 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1528 if (do_verify_nursery || do_dump_nursery_content)
1529 sgen_debug_verify_nursery (do_dump_nursery_content);
1531 current_collection_generation = GENERATION_NURSERY;
1533 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1535 reset_pinned_from_failed_allocation ();
1537 check_scan_starts ();
1539 sgen_nursery_alloc_prepare_for_minor ();
1543 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
1544 /* FIXME: optimize later to use the higher address where an object can be present */
1545 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
1547 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 ()));
1548 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
1549 g_assert (nursery_section->size >= max_garbage_amount);
1551 /* world must be stopped already */
1553 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1555 sgen_client_pre_collection_checks ();
1557 nursery_section->next_data = nursery_next;
1559 major_collector.start_nursery_collection ();
1561 sgen_memgov_minor_collection_start ();
1565 gc_stats.minor_gc_count ++;
1567 if (whole_heap_check_before_collection) {
1568 sgen_clear_nursery_fragments ();
1569 sgen_check_whole_heap (finish_up_concurrent_mark);
1571 if (consistency_check_at_minor_collection)
1572 sgen_check_consistency ();
1574 sgen_process_fin_stage_entries ();
1575 sgen_process_dislink_stage_entries ();
1577 /* pin from pinned handles */
1578 sgen_init_pinning ();
1579 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1580 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
1581 /* pin cemented objects */
1582 sgen_pin_cemented_objects ();
1583 /* identify pinned objects */
1584 sgen_optimize_pin_queue ();
1585 sgen_pinning_setup_section (nursery_section);
1587 pin_objects_in_nursery (FALSE, ctx);
1588 sgen_pinning_trim_queue_to_section (nursery_section);
1591 time_minor_pinning += TV_ELAPSED (btv, atv);
1592 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (btv, atv));
1593 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1596 * FIXME: When we finish a concurrent collection we do a nursery collection first,
1597 * as part of which we scan the card table. Then, later, we scan the mod union
1598 * cardtable. We should only have to do one.
1600 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
1601 sj->ops = object_ops;
1602 sgen_workers_enqueue_job (&sj->job);
1604 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1606 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1607 SGEN_LOG (2, "Old generation scan: %d usecs", TV_ELAPSED (atv, btv));
1609 sgen_drain_gray_stack (-1, ctx);
1611 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1612 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1615 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1617 enqueue_scan_from_roots_jobs (sgen_get_nursery_start (), nursery_next, object_ops);
1620 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1622 finish_gray_stack (GENERATION_NURSERY, ctx);
1625 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1626 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1628 if (objects_pinned) {
1629 sgen_optimize_pin_queue ();
1630 sgen_pinning_setup_section (nursery_section);
1633 /* walk the pin_queue, build up the fragment list of free memory, unmark
1634 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1637 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1638 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1639 if (!fragment_total)
1642 /* Clear TLABs for all threads */
1643 sgen_clear_tlabs ();
1645 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1647 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1648 SGEN_LOG (2, "Fragment creation: %d usecs, %lu bytes available", TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1650 if (consistency_check_at_minor_collection)
1651 sgen_check_major_refs ();
1653 major_collector.finish_nursery_collection ();
1655 TV_GETTIME (last_minor_collection_end_tv);
1656 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1658 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1660 /* prepare the pin queue for the next collection */
1661 sgen_finish_pinning ();
1662 if (sgen_have_pending_finalizers ()) {
1663 SGEN_LOG (4, "Finalizer-thread wakeup");
1664 sgen_client_finalize_notify ();
1666 sgen_pin_stats_reset ();
1667 /* clear cemented hash */
1668 sgen_cement_clear_below_threshold ();
1670 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
1672 remset.finish_minor_collection ();
1674 check_scan_starts ();
1676 binary_protocol_flush_buffers (FALSE);
1678 sgen_memgov_minor_collection_end ();
1680 /*objects are late pinned because of lack of memory, so a major is a good call*/
1681 needs_major = objects_pinned > 0;
1682 current_collection_generation = -1;
1685 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1687 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1688 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1694 scan_nursery_objects_callback (char *obj, size_t size, ScanCopyContext *ctx)
1697 * This is called on all objects in the nursery, including pinned ones, so we need
1698 * to use sgen_obj_get_descriptor_safe(), which masks out the vtable tag bits.
1700 ctx->ops->scan_object (obj, sgen_obj_get_descriptor_safe (obj), ctx->queue);
1704 scan_nursery_objects (ScanCopyContext ctx)
1706 sgen_scan_area_with_callback (nursery_section->data, nursery_section->end_data,
1707 (IterateObjectCallbackFunc)scan_nursery_objects_callback, (void*)&ctx, FALSE);
1711 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1712 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1713 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1714 } CopyOrMarkFromRootsMode;
1717 major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMode mode, gboolean scan_whole_nursery, SgenObjectOperations *object_ops)
1722 /* FIXME: only use these values for the precise scan
1723 * note that to_space pointers should be excluded anyway...
1725 char *heap_start = NULL;
1726 char *heap_end = (char*)-1;
1727 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, WORKERS_DISTRIBUTE_GRAY_QUEUE);
1728 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1730 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1732 if (scan_whole_nursery)
1733 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "Scanning whole nursery only makes sense when we're finishing a concurrent collection.");
1736 /*This cleans up unused fragments */
1737 sgen_nursery_allocator_prepare_for_pinning ();
1739 if (do_concurrent_checks)
1740 sgen_debug_check_nursery_is_clean ();
1742 /* The concurrent collector doesn't touch the nursery. */
1743 sgen_nursery_alloc_prepare_for_major ();
1750 /* Pinning depends on this */
1751 sgen_clear_nursery_fragments ();
1753 if (whole_heap_check_before_collection)
1754 sgen_check_whole_heap (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT);
1757 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1759 if (!sgen_collection_is_concurrent ())
1760 nursery_section->next_data = sgen_get_nursery_end ();
1761 /* we should also coalesce scanning from sections close to each other
1762 * and deal with pointers outside of the sections later.
1767 sgen_client_pre_collection_checks ();
1770 /* Remsets are not useful for a major collection */
1771 remset.clear_cards ();
1774 sgen_process_fin_stage_entries ();
1775 sgen_process_dislink_stage_entries ();
1778 sgen_init_pinning ();
1779 SGEN_LOG (6, "Collecting pinned addresses");
1780 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1782 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1783 if (major_collector.is_concurrent) {
1785 * The concurrent major collector cannot evict
1786 * yet, so we need to pin cemented objects to
1787 * not break some asserts.
1789 * FIXME: We could evict now!
1791 sgen_pin_cemented_objects ();
1795 sgen_optimize_pin_queue ();
1797 sgen_client_collecting_major_1 ();
1800 * pin_queue now contains all candidate pointers, sorted and
1801 * uniqued. We must do two passes now to figure out which
1802 * objects are pinned.
1804 * The first is to find within the pin_queue the area for each
1805 * section. This requires that the pin_queue be sorted. We
1806 * also process the LOS objects and pinned chunks here.
1808 * The second, destructive, pass is to reduce the section
1809 * areas to pointers to the actually pinned objects.
1811 SGEN_LOG (6, "Pinning from sections");
1812 /* first pass for the sections */
1813 sgen_find_section_pin_queue_start_end (nursery_section);
1814 /* identify possible pointers to the insize of large objects */
1815 SGEN_LOG (6, "Pinning from large objects");
1816 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1818 if (sgen_find_optimized_pin_queue_area (bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1819 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (((GCObject*)(bigobj->data))));
1821 if (sgen_los_object_is_pinned (bigobj->data)) {
1822 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1825 sgen_los_pin_object (bigobj->data);
1826 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1827 GRAY_OBJECT_ENQUEUE (WORKERS_DISTRIBUTE_GRAY_QUEUE, bigobj->data, sgen_obj_get_descriptor (bigobj->data));
1828 sgen_pin_stats_register_object ((char*) bigobj->data, safe_object_get_size ((GCObject*) bigobj->data));
1829 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1830 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1831 (unsigned long)sgen_los_object_size (bigobj));
1833 sgen_client_pinned_los_object (bigobj->data);
1836 /* second pass for the sections */
1839 * Concurrent mark never follows references into the nursery. In the start and
1840 * finish pauses we must scan live nursery objects, though.
1842 * In the finish pause we do this conservatively by scanning all nursery objects.
1843 * Previously we would only scan pinned objects here. We assumed that all objects
1844 * that were pinned during the nursery collection immediately preceding this finish
1845 * mark would be pinned again here. Due to the way we get the stack end for the GC
1846 * thread, however, that's not necessarily the case: we scan part of the stack used
1847 * by the GC itself, which changes constantly, so pinning isn't entirely
1850 * The split nursery also complicates things because non-pinned objects can survive
1851 * in the nursery. That's why we need to do a full scan of the nursery for it, too.
1853 * In the future we shouldn't do a preceding nursery collection at all and instead
1854 * do the finish pause with promotion from the nursery.
1856 * A further complication arises when we have late-pinned objects from the preceding
1857 * nursery collection. Those are the result of being out of memory when trying to
1858 * evacuate objects. They won't be found from the roots, so we just scan the whole
1861 * Non-concurrent mark evacuates from the nursery, so it's
1862 * sufficient to just scan pinned nursery objects.
1864 if (scan_whole_nursery || mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT || (concurrent && sgen_minor_collector.is_split)) {
1865 scan_nursery_objects (ctx);
1867 pin_objects_in_nursery (concurrent, ctx);
1868 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1869 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1872 major_collector.pin_objects (WORKERS_DISTRIBUTE_GRAY_QUEUE);
1873 if (old_next_pin_slot)
1874 *old_next_pin_slot = sgen_get_pinned_count ();
1877 time_major_pinning += TV_ELAPSED (atv, btv);
1878 SGEN_LOG (2, "Finding pinned pointers: %zd in %d usecs", sgen_get_pinned_count (), TV_ELAPSED (atv, btv));
1879 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1881 major_collector.init_to_space ();
1884 * The concurrent collector doesn't move objects, neither on
1885 * the major heap nor in the nursery, so we can mark even
1886 * before pinning has finished. For the non-concurrent
1887 * collector we start the workers after pinning.
1889 if (mode != COPY_OR_MARK_FROM_ROOTS_SERIAL) {
1890 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1891 sgen_workers_start_all_workers (object_ops);
1892 gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
1895 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1896 main_gc_thread = mono_native_thread_self ();
1899 sgen_client_collecting_major_2 ();
1902 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1904 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1907 * FIXME: is this the right context? It doesn't seem to contain a copy function
1908 * unless we're concurrent.
1910 enqueue_scan_from_roots_jobs (heap_start, heap_end, object_ops);
1913 time_major_scan_roots += TV_ELAPSED (atv, btv);
1915 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1918 /* Mod union card table */
1919 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ScanJob));
1920 sj->ops = object_ops;
1921 sgen_workers_enqueue_job (&sj->job);
1923 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ScanJob));
1924 sj->ops = object_ops;
1925 sgen_workers_enqueue_job (&sj->job);
1928 time_major_scan_mod_union += TV_ELAPSED (btv, atv);
1933 major_finish_copy_or_mark (void)
1935 if (!concurrent_collection_in_progress)
1939 * Prepare the pin queue for the next collection. Since pinning runs on the worker
1940 * threads we must wait for the jobs to finish before we can reset it.
1942 sgen_workers_wait_for_jobs_finished ();
1943 sgen_finish_pinning ();
1945 sgen_pin_stats_reset ();
1947 if (do_concurrent_checks)
1948 sgen_debug_check_nursery_is_clean ();
1952 major_start_collection (gboolean concurrent, size_t *old_next_pin_slot)
1954 SgenObjectOperations *object_ops;
1956 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
1958 current_collection_generation = GENERATION_OLD;
1960 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
1962 sgen_cement_reset ();
1965 g_assert (major_collector.is_concurrent);
1966 concurrent_collection_in_progress = TRUE;
1968 object_ops = &major_collector.major_ops_concurrent_start;
1970 object_ops = &major_collector.major_ops_serial;
1973 reset_pinned_from_failed_allocation ();
1975 sgen_memgov_major_collection_start ();
1977 //count_ref_nonref_objs ();
1978 //consistency_check ();
1980 check_scan_starts ();
1983 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
1984 gc_stats.major_gc_count ++;
1986 if (major_collector.start_major_collection)
1987 major_collector.start_major_collection ();
1989 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);
1990 major_finish_copy_or_mark ();
1994 major_finish_collection (const char *reason, size_t old_next_pin_slot, gboolean forced, gboolean scan_whole_nursery)
1996 ScannedObjectCounts counts;
1997 SgenObjectOperations *object_ops;
2003 if (concurrent_collection_in_progress) {
2004 object_ops = &major_collector.major_ops_concurrent_finish;
2006 major_copy_or_mark_from_roots (NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, scan_whole_nursery, object_ops);
2008 major_finish_copy_or_mark ();
2010 sgen_workers_join ();
2012 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty after workers have finished working?");
2014 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2015 main_gc_thread = NULL;
2018 if (do_concurrent_checks)
2019 sgen_debug_check_nursery_is_clean ();
2021 SGEN_ASSERT (0, !scan_whole_nursery, "scan_whole_nursery only applies to concurrent collections");
2022 object_ops = &major_collector.major_ops_serial;
2026 * The workers have stopped so we need to finish gray queue
2027 * work that might result from finalization in the main GC
2028 * thread. Redirection must therefore be turned off.
2030 sgen_gray_object_queue_disable_alloc_prepare (&gray_queue);
2031 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2033 /* all the objects in the heap */
2034 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gray_queue));
2036 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2038 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2040 if (objects_pinned) {
2041 g_assert (!concurrent_collection_in_progress);
2044 * This is slow, but we just OOM'd.
2046 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2047 * queue is laid out at this point.
2049 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2051 * We need to reestablish all pinned nursery objects in the pin queue
2052 * because they're needed for fragment creation. Unpinning happens by
2053 * walking the whole queue, so it's not necessary to reestablish where major
2054 * heap block pins are - all we care is that they're still in there
2057 sgen_optimize_pin_queue ();
2058 sgen_find_section_pin_queue_start_end (nursery_section);
2062 reset_heap_boundaries ();
2063 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2065 if (!concurrent_collection_in_progress) {
2066 /* walk the pin_queue, build up the fragment list of free memory, unmark
2067 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2070 if (!sgen_build_nursery_fragments (nursery_section, NULL))
2073 /* prepare the pin queue for the next collection */
2074 sgen_finish_pinning ();
2076 /* Clear TLABs for all threads */
2077 sgen_clear_tlabs ();
2079 sgen_pin_stats_reset ();
2082 sgen_cement_clear_below_threshold ();
2084 if (check_mark_bits_after_major_collection)
2085 sgen_check_heap_marked (concurrent_collection_in_progress);
2088 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2090 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2093 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2098 time_major_los_sweep += TV_ELAPSED (atv, btv);
2100 major_collector.sweep ();
2102 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2105 time_major_sweep += TV_ELAPSED (btv, atv);
2107 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2109 if (sgen_have_pending_finalizers ()) {
2110 SGEN_LOG (4, "Finalizer-thread wakeup");
2111 sgen_client_finalize_notify ();
2114 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2116 sgen_memgov_major_collection_end (forced);
2117 current_collection_generation = -1;
2119 memset (&counts, 0, sizeof (ScannedObjectCounts));
2120 major_collector.finish_major_collection (&counts);
2122 g_assert (sgen_section_gray_queue_is_empty (sgen_workers_get_distribute_section_gray_queue ()));
2124 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2125 if (concurrent_collection_in_progress)
2126 concurrent_collection_in_progress = FALSE;
2128 check_scan_starts ();
2130 binary_protocol_flush_buffers (FALSE);
2132 //consistency_check ();
2134 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2138 major_do_collection (const char *reason, gboolean forced)
2140 TV_DECLARE (time_start);
2141 TV_DECLARE (time_end);
2142 size_t old_next_pin_slot;
2144 if (disable_major_collections)
2147 if (major_collector.get_and_reset_num_major_objects_marked) {
2148 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2149 g_assert (!num_marked);
2152 /* world must be stopped already */
2153 TV_GETTIME (time_start);
2155 major_start_collection (FALSE, &old_next_pin_slot);
2156 major_finish_collection (reason, old_next_pin_slot, forced, FALSE);
2158 TV_GETTIME (time_end);
2159 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2161 /* FIXME: also report this to the user, preferably in gc-end. */
2162 if (major_collector.get_and_reset_num_major_objects_marked)
2163 major_collector.get_and_reset_num_major_objects_marked ();
2165 return bytes_pinned_from_failed_allocation > 0;
2169 major_start_concurrent_collection (const char *reason)
2171 TV_DECLARE (time_start);
2172 TV_DECLARE (time_end);
2173 long long num_objects_marked;
2175 if (disable_major_collections)
2178 TV_GETTIME (time_start);
2179 SGEN_TV_GETTIME (time_major_conc_collection_start);
2181 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2182 g_assert (num_objects_marked == 0);
2184 binary_protocol_concurrent_start ();
2186 // FIXME: store reason and pass it when finishing
2187 major_start_collection (TRUE, NULL);
2189 gray_queue_redirect (&gray_queue);
2191 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2193 TV_GETTIME (time_end);
2194 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2196 current_collection_generation = -1;
2200 * Returns whether the major collection has finished.
2203 major_should_finish_concurrent_collection (void)
2205 SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&gray_queue), "Why is the gray queue not empty before we have started doing anything?");
2206 return sgen_workers_all_done ();
2210 major_update_concurrent_collection (void)
2212 TV_DECLARE (total_start);
2213 TV_DECLARE (total_end);
2215 TV_GETTIME (total_start);
2217 binary_protocol_concurrent_update ();
2219 major_collector.update_cardtable_mod_union ();
2220 sgen_los_update_cardtable_mod_union ();
2222 TV_GETTIME (total_end);
2223 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2227 major_finish_concurrent_collection (gboolean forced)
2229 TV_DECLARE (total_start);
2230 TV_DECLARE (total_end);
2231 gboolean late_pinned;
2232 SgenGrayQueue unpin_queue;
2233 memset (&unpin_queue, 0, sizeof (unpin_queue));
2235 TV_GETTIME (total_start);
2237 binary_protocol_concurrent_finish ();
2240 * The major collector can add global remsets which are processed in the finishing
2241 * nursery collection, below. That implies that the workers must have finished
2242 * marking before the nursery collection is allowed to run, otherwise we might miss
2245 sgen_workers_wait ();
2247 SGEN_TV_GETTIME (time_major_conc_collection_end);
2248 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2250 major_collector.update_cardtable_mod_union ();
2251 sgen_los_update_cardtable_mod_union ();
2253 late_pinned = collect_nursery (&unpin_queue, TRUE);
2255 if (mod_union_consistency_check)
2256 sgen_check_mod_union_consistency ();
2258 current_collection_generation = GENERATION_OLD;
2259 major_finish_collection ("finishing", -1, forced, late_pinned);
2261 if (whole_heap_check_before_collection)
2262 sgen_check_whole_heap (FALSE);
2264 unpin_objects_from_queue (&unpin_queue);
2265 sgen_gray_object_queue_deinit (&unpin_queue);
2267 TV_GETTIME (total_end);
2268 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end) - TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
2270 current_collection_generation = -1;
2274 * Ensure an allocation request for @size will succeed by freeing enough memory.
2276 * LOCKING: The GC lock MUST be held.
2279 sgen_ensure_free_space (size_t size)
2281 int generation_to_collect = -1;
2282 const char *reason = NULL;
2284 if (size > SGEN_MAX_SMALL_OBJ_SIZE) {
2285 if (sgen_need_major_collection (size)) {
2286 reason = "LOS overflow";
2287 generation_to_collect = GENERATION_OLD;
2290 if (degraded_mode) {
2291 if (sgen_need_major_collection (size)) {
2292 reason = "Degraded mode overflow";
2293 generation_to_collect = GENERATION_OLD;
2295 } else if (sgen_need_major_collection (size)) {
2296 reason = "Minor allowance";
2297 generation_to_collect = GENERATION_OLD;
2299 generation_to_collect = GENERATION_NURSERY;
2300 reason = "Nursery full";
2304 if (generation_to_collect == -1) {
2305 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2306 generation_to_collect = GENERATION_OLD;
2307 reason = "Finish concurrent collection";
2311 if (generation_to_collect == -1)
2313 sgen_perform_collection (size, generation_to_collect, reason, FALSE);
2317 * LOCKING: Assumes the GC lock is held.
2320 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish)
2322 TV_DECLARE (gc_start);
2323 TV_DECLARE (gc_end);
2324 TV_DECLARE (gc_total_start);
2325 TV_DECLARE (gc_total_end);
2326 GGTimingInfo infos [2];
2327 int overflow_generation_to_collect = -1;
2328 int oldest_generation_collected = generation_to_collect;
2329 const char *overflow_reason = NULL;
2331 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2333 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2335 TV_GETTIME (gc_start);
2337 sgen_stop_world (generation_to_collect);
2339 TV_GETTIME (gc_total_start);
2341 if (concurrent_collection_in_progress) {
2343 * We update the concurrent collection. If it finished, we're done. If
2344 * not, and we've been asked to do a nursery collection, we do that.
2346 gboolean finish = major_should_finish_concurrent_collection () || (wait_to_finish && generation_to_collect == GENERATION_OLD);
2349 major_finish_concurrent_collection (wait_to_finish);
2350 oldest_generation_collected = GENERATION_OLD;
2352 sgen_workers_signal_start_nursery_collection_and_wait ();
2354 major_update_concurrent_collection ();
2355 if (generation_to_collect == GENERATION_NURSERY)
2356 collect_nursery (NULL, FALSE);
2358 sgen_workers_signal_finish_nursery_collection ();
2365 * If we've been asked to do a major collection, and the major collector wants to
2366 * run synchronously (to evacuate), we set the flag to do that.
2368 if (generation_to_collect == GENERATION_OLD &&
2369 allow_synchronous_major &&
2370 major_collector.want_synchronous_collection &&
2371 *major_collector.want_synchronous_collection) {
2372 wait_to_finish = TRUE;
2375 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
2378 * There's no concurrent collection in progress. Collect the generation we're asked
2379 * to collect. If the major collector is concurrent and we're not forced to wait,
2380 * start a concurrent collection.
2382 // FIXME: extract overflow reason
2383 if (generation_to_collect == GENERATION_NURSERY) {
2384 if (collect_nursery (NULL, FALSE)) {
2385 overflow_generation_to_collect = GENERATION_OLD;
2386 overflow_reason = "Minor overflow";
2389 if (major_collector.is_concurrent && !wait_to_finish) {
2390 collect_nursery (NULL, FALSE);
2391 major_start_concurrent_collection (reason);
2392 // FIXME: set infos[0] properly
2396 if (major_do_collection (reason, wait_to_finish)) {
2397 overflow_generation_to_collect = GENERATION_NURSERY;
2398 overflow_reason = "Excessive pinning";
2402 TV_GETTIME (gc_end);
2404 memset (infos, 0, sizeof (infos));
2405 infos [0].generation = generation_to_collect;
2406 infos [0].reason = reason;
2407 infos [0].is_overflow = FALSE;
2408 infos [1].generation = -1;
2409 infos [0].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
2411 SGEN_ASSERT (0, !concurrent_collection_in_progress, "Why did this not get handled above?");
2413 if (overflow_generation_to_collect != -1) {
2415 * We need to do an overflow collection, either because we ran out of memory
2416 * or the nursery is fully pinned.
2419 infos [1].generation = overflow_generation_to_collect;
2420 infos [1].reason = overflow_reason;
2421 infos [1].is_overflow = TRUE;
2424 if (overflow_generation_to_collect == GENERATION_NURSERY)
2425 collect_nursery (NULL, FALSE);
2427 major_do_collection (overflow_reason, wait_to_finish);
2429 TV_GETTIME (gc_end);
2430 infos [1].total_time = SGEN_TV_ELAPSED (gc_start, gc_end);
2432 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2435 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2437 /* this also sets the proper pointers for the next allocation */
2438 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2439 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2440 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2441 sgen_dump_pin_queue ();
2446 g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
2448 TV_GETTIME (gc_total_end);
2449 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2451 sgen_restart_world (oldest_generation_collected, infos);
2455 * ######################################################################
2456 * ######## Memory allocation from the OS
2457 * ######################################################################
2458 * This section of code deals with getting memory from the OS and
2459 * allocating memory for GC-internal data structures.
2460 * Internal memory can be handled with a freelist for small objects.
2466 G_GNUC_UNUSED static void
2467 report_internal_mem_usage (void)
2469 printf ("Internal memory usage:\n");
2470 sgen_report_internal_mem_usage ();
2471 printf ("Pinned memory usage:\n");
2472 major_collector.report_pinned_memory_usage ();
2476 * ######################################################################
2477 * ######## Finalization support
2478 * ######################################################################
2482 * If the object has been forwarded it means it's still referenced from a root.
2483 * If it is pinned it's still alive as well.
2484 * A LOS object is only alive if we have pinned it.
2485 * Return TRUE if @obj is ready to be finalized.
2487 static inline gboolean
2488 sgen_is_object_alive (void *object)
2490 if (ptr_in_nursery (object))
2491 return sgen_nursery_is_object_alive (object);
2493 return sgen_major_is_object_alive (object);
2497 * This function returns true if @object is either alive and belongs to the
2498 * current collection - major collections are full heap, so old gen objects
2499 * are never alive during a minor collection.
2502 sgen_is_object_alive_and_on_current_collection (char *object)
2504 if (ptr_in_nursery (object))
2505 return sgen_nursery_is_object_alive (object);
2507 if (current_collection_generation == GENERATION_NURSERY)
2510 return sgen_major_is_object_alive (object);
2515 sgen_gc_is_object_ready_for_finalization (void *object)
2517 return !sgen_is_object_alive (object);
2521 sgen_queue_finalization_entry (GCObject *obj)
2523 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2525 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2527 sgen_client_object_queued_for_finalization (obj);
2531 sgen_object_is_live (void *obj)
2533 return sgen_is_object_alive_and_on_current_collection (obj);
2537 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2538 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2539 * all finalizers have really finished running.
2541 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2542 * This means that just checking whether the queues are empty leaves the possibility that an
2543 * object might have been dequeued but not yet finalized. That's why we need the additional
2544 * flag `pending_unqueued_finalizer`.
2547 static volatile gboolean pending_unqueued_finalizer = FALSE;
2550 sgen_gc_invoke_finalizers (void)
2554 g_assert (!pending_unqueued_finalizer);
2556 /* FIXME: batch to reduce lock contention */
2557 while (sgen_have_pending_finalizers ()) {
2563 * We need to set `pending_unqueued_finalizer` before dequeing the
2564 * finalizable object.
2566 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2567 pending_unqueued_finalizer = TRUE;
2568 mono_memory_write_barrier ();
2569 obj = sgen_pointer_queue_pop (&fin_ready_queue);
2570 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2571 pending_unqueued_finalizer = TRUE;
2572 mono_memory_write_barrier ();
2573 obj = sgen_pointer_queue_pop (&critical_fin_queue);
2579 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2587 /* the object is on the stack so it is pinned */
2588 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2589 sgen_client_run_finalize (obj);
2592 if (pending_unqueued_finalizer) {
2593 mono_memory_write_barrier ();
2594 pending_unqueued_finalizer = FALSE;
2601 sgen_have_pending_finalizers (void)
2603 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2607 * ######################################################################
2608 * ######## registered roots support
2609 * ######################################################################
2613 * We do not coalesce roots.
2616 sgen_register_root (char *start, size_t size, void *descr, int root_type)
2618 RootRecord new_root;
2621 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2622 RootRecord *root = sgen_hash_table_lookup (&roots_hash [i], start);
2623 /* we allow changing the size and the descriptor (for thread statics etc) */
2625 size_t old_size = root->end_root - start;
2626 root->end_root = start + size;
2627 g_assert (((root->root_desc != 0) && (descr != NULL)) ||
2628 ((root->root_desc == 0) && (descr == NULL)));
2629 root->root_desc = (mword)descr;
2631 roots_size -= old_size;
2637 new_root.end_root = start + size;
2638 new_root.root_desc = (mword)descr;
2640 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2643 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);
2650 sgen_deregister_root (char* addr)
2656 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2657 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2658 roots_size -= (root.end_root - addr);
2664 * ######################################################################
2665 * ######## Thread handling (stop/start code)
2666 * ######################################################################
2670 sgen_get_current_collection_generation (void)
2672 return current_collection_generation;
2676 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2678 #ifndef HAVE_KW_THREAD
2679 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2682 sgen_init_tlab_info (info);
2684 sgen_client_thread_register (info, stack_bottom_fallback);
2690 sgen_thread_unregister (SgenThreadInfo *p)
2692 sgen_client_thread_unregister (p);
2697 * ######################################################################
2698 * ######## Write barriers
2699 * ######################################################################
2703 * Note: the write barriers first do the needed GC work and then do the actual store:
2704 * this way the value is visible to the conservative GC scan after the write barrier
2705 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2706 * the conservative scan, otherwise by the remembered set scan.
2709 mono_gc_wbarrier_set_field (GCObject *obj, gpointer field_ptr, GCObject* value)
2711 HEAVY_STAT (++stat_wbarrier_set_field);
2712 if (ptr_in_nursery (field_ptr)) {
2713 *(void**)field_ptr = value;
2716 SGEN_LOG (8, "Adding remset at %p", field_ptr);
2718 binary_protocol_wbarrier (field_ptr, value, value->vtable);
2720 remset.wbarrier_set_field (obj, field_ptr, value);
2724 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2726 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2727 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2728 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2729 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2733 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2734 if (binary_protocol_is_heavy_enabled ()) {
2736 for (i = 0; i < count; ++i) {
2737 gpointer dest = (gpointer*)dest_ptr + i;
2738 gpointer obj = *((gpointer*)src_ptr + i);
2740 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2745 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2749 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2753 HEAVY_STAT (++stat_wbarrier_generic_store);
2755 sgen_client_wbarrier_generic_nostore_check (ptr);
2757 obj = *(gpointer*)ptr;
2759 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2762 * We need to record old->old pointer locations for the
2763 * concurrent collector.
2765 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2766 SGEN_LOG (8, "Skipping remset at %p", ptr);
2770 SGEN_LOG (8, "Adding remset at %p", ptr);
2772 remset.wbarrier_generic_nostore (ptr);
2776 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2778 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2779 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2780 if (ptr_in_nursery (value))
2781 mono_gc_wbarrier_generic_nostore (ptr);
2782 sgen_dummy_use (value);
2785 /* Same as mono_gc_wbarrier_generic_store () but performs the store
2786 * as an atomic operation with release semantics.
2789 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2791 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2793 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2795 InterlockedWritePointer (ptr, value);
2797 if (ptr_in_nursery (value))
2798 mono_gc_wbarrier_generic_nostore (ptr);
2800 sgen_dummy_use (value);
2804 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
2806 GCObject **dest = _dest;
2807 GCObject **src = _src;
2811 mono_gc_wbarrier_generic_store (dest, *src);
2813 SGEN_UPDATE_REFERENCE_ALLOW_NULL (dest, *src);
2816 size -= SIZEOF_VOID_P;
2822 * ######################################################################
2823 * ######## Other mono public interface functions.
2824 * ######################################################################
2828 sgen_gc_collect (int generation)
2833 sgen_perform_collection (0, generation, "user request", TRUE);
2838 sgen_gc_collection_count (int generation)
2840 if (generation == 0)
2841 return gc_stats.minor_gc_count;
2842 return gc_stats.major_gc_count;
2846 sgen_gc_get_used_size (void)
2850 tot = los_memory_usage;
2851 tot += nursery_section->next_data - nursery_section->data;
2852 tot += major_collector.get_used_size ();
2853 /* FIXME: account for pinned objects */
2859 sgen_weak_link_get (void **link_addr)
2861 void * volatile *link_addr_volatile;
2865 link_addr_volatile = link_addr;
2866 ptr = (void*)*link_addr_volatile;
2868 * At this point we have a hidden pointer. If the GC runs
2869 * here, it will not recognize the hidden pointer as a
2870 * reference, and if the object behind it is not referenced
2871 * elsewhere, it will be freed. Once the world is restarted
2872 * we reveal the pointer, giving us a pointer to a freed
2873 * object. To make sure we don't return it, we load the
2874 * hidden pointer again. If it's still the same, we can be
2875 * sure the object reference is valid.
2878 obj = (GCObject*) REVEAL_POINTER (ptr);
2882 mono_memory_barrier ();
2885 * During the second bridge processing step the world is
2886 * running again. That step processes all weak links once
2887 * more to null those that refer to dead objects. Before that
2888 * is completed, those links must not be followed, so we
2889 * conservatively wait for bridge processing when any weak
2890 * link is dereferenced.
2892 sgen_client_bridge_wait_for_processing ();
2894 if ((void*)*link_addr_volatile != ptr)
2901 sgen_set_allow_synchronous_major (gboolean flag)
2903 if (!major_collector.is_concurrent)
2906 allow_synchronous_major = flag;
2911 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2915 va_start (ap, description_format);
2917 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2918 vfprintf (stderr, description_format, ap);
2920 fprintf (stderr, " - %s", fallback);
2921 fprintf (stderr, "\n");
2927 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2930 double val = strtod (opt, &endptr);
2931 if (endptr == opt) {
2932 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2935 else if (val < min || val > max) {
2936 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
2948 char *major_collector_opt = NULL;
2949 char *minor_collector_opt = NULL;
2950 size_t max_heap = 0;
2951 size_t soft_limit = 0;
2954 gboolean debug_print_allowance = FALSE;
2955 double allowance_ratio = 0, save_target = 0;
2956 gboolean cement_enabled = TRUE;
2959 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
2962 /* already inited */
2965 /* being inited by another thread */
2969 /* we will init it */
2972 g_assert_not_reached ();
2974 } while (result != 0);
2976 SGEN_TV_GETTIME (sgen_init_timestamp);
2978 #ifdef SGEN_WITHOUT_MONO
2979 mono_thread_smr_init ();
2982 LOCK_INIT (gc_mutex);
2984 gc_debug_file = stderr;
2986 LOCK_INIT (sgen_interruption_mutex);
2988 if ((env = g_getenv (MONO_GC_PARAMS_NAME))) {
2989 opts = g_strsplit (env, ",", -1);
2990 for (ptr = opts; *ptr; ++ptr) {
2992 if (g_str_has_prefix (opt, "major=")) {
2993 opt = strchr (opt, '=') + 1;
2994 major_collector_opt = g_strdup (opt);
2995 } else if (g_str_has_prefix (opt, "minor=")) {
2996 opt = strchr (opt, '=') + 1;
2997 minor_collector_opt = g_strdup (opt);
3005 sgen_init_internal_allocator ();
3006 sgen_init_nursery_allocator ();
3007 sgen_init_fin_weak_hash ();
3008 sgen_init_hash_table ();
3009 sgen_init_descriptors ();
3010 sgen_init_gray_queues ();
3011 sgen_init_allocator ();
3013 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
3014 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
3016 sgen_client_init ();
3018 /* FIXME: Move this to mono code! */
3019 mono_gc_register_thread (&dummy);
3021 if (!minor_collector_opt) {
3022 sgen_simple_nursery_init (&sgen_minor_collector);
3024 if (!strcmp (minor_collector_opt, "simple")) {
3026 sgen_simple_nursery_init (&sgen_minor_collector);
3027 } else if (!strcmp (minor_collector_opt, "split")) {
3028 sgen_split_nursery_init (&sgen_minor_collector);
3030 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
3031 goto use_simple_nursery;
3035 if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep")) {
3036 use_marksweep_major:
3037 sgen_marksweep_init (&major_collector);
3038 } else if (!major_collector_opt || !strcmp (major_collector_opt, "marksweep-conc")) {
3039 sgen_marksweep_conc_init (&major_collector);
3041 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `marksweep` instead.", "Unknown major collector `%s'.", major_collector_opt);
3042 goto use_marksweep_major;
3045 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
3047 if (major_collector.is_concurrent)
3048 cement_enabled = FALSE;
3051 gboolean usage_printed = FALSE;
3053 for (ptr = opts; *ptr; ++ptr) {
3055 if (!strcmp (opt, ""))
3057 if (g_str_has_prefix (opt, "major="))
3059 if (g_str_has_prefix (opt, "minor="))
3061 if (g_str_has_prefix (opt, "max-heap-size=")) {
3062 size_t page_size = mono_pagesize ();
3063 size_t max_heap_candidate = 0;
3064 opt = strchr (opt, '=') + 1;
3065 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
3066 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
3067 if (max_heap != max_heap_candidate)
3068 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
3070 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
3074 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
3075 opt = strchr (opt, '=') + 1;
3076 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
3077 if (soft_limit <= 0) {
3078 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
3082 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
3088 if (g_str_has_prefix (opt, "nursery-size=")) {
3090 opt = strchr (opt, '=') + 1;
3091 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
3092 if ((val & (val - 1))) {
3093 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
3097 if (val < SGEN_MAX_NURSERY_WASTE) {
3098 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3099 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
3103 sgen_nursery_size = val;
3104 sgen_nursery_bits = 0;
3105 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
3108 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
3114 if (g_str_has_prefix (opt, "save-target-ratio=")) {
3116 opt = strchr (opt, '=') + 1;
3117 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
3118 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
3123 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
3125 opt = strchr (opt, '=') + 1;
3126 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
3127 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3128 allowance_ratio = val;
3132 if (g_str_has_prefix (opt, "allow-synchronous-major=")) {
3133 if (!major_collector.is_concurrent) {
3134 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`allow-synchronous-major` is only valid for the concurrent major collector.");
3138 opt = strchr (opt, '=') + 1;
3140 if (!strcmp (opt, "yes")) {
3141 allow_synchronous_major = TRUE;
3142 } else if (!strcmp (opt, "no")) {
3143 allow_synchronous_major = FALSE;
3145 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`allow-synchronous-major` must be either `yes' or `no'.");
3150 if (!strcmp (opt, "cementing")) {
3151 cement_enabled = TRUE;
3154 if (!strcmp (opt, "no-cementing")) {
3155 cement_enabled = FALSE;
3159 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3162 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3165 if (sgen_client_handle_gc_param (opt))
3168 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3173 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3174 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3175 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3176 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3177 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3178 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3179 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3180 fprintf (stderr, " [no-]cementing\n");
3181 if (major_collector.is_concurrent)
3182 fprintf (stderr, " allow-synchronous-major=FLAG (where FLAG is `yes' or `no')\n");
3183 if (major_collector.print_gc_param_usage)
3184 major_collector.print_gc_param_usage ();
3185 if (sgen_minor_collector.print_gc_param_usage)
3186 sgen_minor_collector.print_gc_param_usage ();
3187 sgen_client_print_gc_params_usage ();
3188 fprintf (stderr, " Experimental options:\n");
3189 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3190 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);
3191 fprintf (stderr, "\n");
3193 usage_printed = TRUE;
3198 if (major_collector_opt)
3199 g_free (major_collector_opt);
3201 if (minor_collector_opt)
3202 g_free (minor_collector_opt);
3206 if (major_collector.is_concurrent && cement_enabled) {
3207 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "`cementing` is not supported on concurrent major collectors.");
3208 cement_enabled = FALSE;
3211 sgen_cement_init (cement_enabled);
3213 if ((env = g_getenv (MONO_GC_DEBUG_NAME))) {
3214 gboolean usage_printed = FALSE;
3216 opts = g_strsplit (env, ",", -1);
3217 for (ptr = opts; ptr && *ptr; ptr ++) {
3219 if (!strcmp (opt, ""))
3221 if (opt [0] >= '0' && opt [0] <= '9') {
3222 gc_debug_level = atoi (opt);
3227 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3228 gc_debug_file = fopen (rf, "wb");
3230 gc_debug_file = stderr;
3233 } else if (!strcmp (opt, "print-allowance")) {
3234 debug_print_allowance = TRUE;
3235 } else if (!strcmp (opt, "print-pinning")) {
3236 sgen_pin_stats_enable ();
3237 } else if (!strcmp (opt, "verify-before-allocs")) {
3238 verify_before_allocs = 1;
3239 has_per_allocation_action = TRUE;
3240 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3241 char *arg = strchr (opt, '=') + 1;
3242 verify_before_allocs = atoi (arg);
3243 has_per_allocation_action = TRUE;
3244 } else if (!strcmp (opt, "collect-before-allocs")) {
3245 collect_before_allocs = 1;
3246 has_per_allocation_action = TRUE;
3247 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3248 char *arg = strchr (opt, '=') + 1;
3249 has_per_allocation_action = TRUE;
3250 collect_before_allocs = atoi (arg);
3251 } else if (!strcmp (opt, "verify-before-collections")) {
3252 whole_heap_check_before_collection = TRUE;
3253 } else if (!strcmp (opt, "check-at-minor-collections")) {
3254 consistency_check_at_minor_collection = TRUE;
3255 nursery_clear_policy = CLEAR_AT_GC;
3256 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3257 if (!major_collector.is_concurrent) {
3258 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3261 mod_union_consistency_check = TRUE;
3262 } else if (!strcmp (opt, "check-mark-bits")) {
3263 check_mark_bits_after_major_collection = TRUE;
3264 } else if (!strcmp (opt, "check-nursery-pinned")) {
3265 check_nursery_objects_pinned = TRUE;
3266 } else if (!strcmp (opt, "clear-at-gc")) {
3267 nursery_clear_policy = CLEAR_AT_GC;
3268 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3269 nursery_clear_policy = CLEAR_AT_GC;
3270 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3271 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3272 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3273 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3274 } else if (!strcmp (opt, "check-scan-starts")) {
3275 do_scan_starts_check = TRUE;
3276 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3277 do_verify_nursery = TRUE;
3278 } else if (!strcmp (opt, "check-concurrent")) {
3279 if (!major_collector.is_concurrent) {
3280 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3283 do_concurrent_checks = TRUE;
3284 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3285 do_dump_nursery_content = TRUE;
3286 } else if (!strcmp (opt, "disable-minor")) {
3287 disable_minor_collections = TRUE;
3288 } else if (!strcmp (opt, "disable-major")) {
3289 disable_major_collections = TRUE;
3290 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3291 char *filename = strchr (opt, '=') + 1;
3292 nursery_clear_policy = CLEAR_AT_GC;
3293 sgen_debug_enable_heap_dump (filename);
3294 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3295 char *filename = strchr (opt, '=') + 1;
3296 char *colon = strrchr (filename, ':');
3299 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3300 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3305 binary_protocol_init (filename, (long long)limit);
3306 } else if (!strcmp (opt, "nursery-canaries")) {
3307 do_verify_nursery = TRUE;
3308 enable_nursery_canaries = TRUE;
3309 } else if (!sgen_client_handle_gc_debug (opt)) {
3310 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3315 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);
3316 fprintf (stderr, "Valid <option>s are:\n");
3317 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3318 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3319 fprintf (stderr, " check-at-minor-collections\n");
3320 fprintf (stderr, " check-mark-bits\n");
3321 fprintf (stderr, " check-nursery-pinned\n");
3322 fprintf (stderr, " verify-before-collections\n");
3323 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3324 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3325 fprintf (stderr, " disable-minor\n");
3326 fprintf (stderr, " disable-major\n");
3327 fprintf (stderr, " check-concurrent\n");
3328 fprintf (stderr, " clear-[nursery-]at-gc\n");
3329 fprintf (stderr, " clear-at-tlab-creation\n");
3330 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3331 fprintf (stderr, " check-scan-starts\n");
3332 fprintf (stderr, " print-allowance\n");
3333 fprintf (stderr, " print-pinning\n");
3334 fprintf (stderr, " heap-dump=<filename>\n");
3335 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3336 fprintf (stderr, " nursery-canaries\n");
3337 sgen_client_print_gc_debug_usage ();
3338 fprintf (stderr, "\n");
3340 usage_printed = TRUE;
3346 if (check_mark_bits_after_major_collection)
3347 nursery_clear_policy = CLEAR_AT_GC;
3349 if (major_collector.post_param_init)
3350 major_collector.post_param_init (&major_collector);
3352 if (major_collector.needs_thread_pool)
3353 sgen_workers_init (1);
3355 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3357 memset (&remset, 0, sizeof (remset));
3359 sgen_card_table_init (&remset);
3365 sgen_get_nursery_clear_policy (void)
3367 return nursery_clear_policy;
3377 sgen_gc_unlock (void)
3379 gboolean try_free = sgen_try_free_some_memory;
3380 sgen_try_free_some_memory = FALSE;
3381 mono_mutex_unlock (&gc_mutex);
3383 mono_thread_hazardous_try_free_some ();
3387 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3389 major_collector.iterate_live_block_ranges (callback);
3393 sgen_get_major_collector (void)
3395 return &major_collector;
3399 sgen_get_remset (void)
3405 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3407 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3408 sgen_los_count_cards (los_total, los_marked);
3411 static gboolean world_is_stopped = FALSE;
3413 /* LOCKING: assumes the GC lock is held */
3415 sgen_stop_world (int generation)
3417 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3419 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3421 binary_protocol_world_stopping (generation, sgen_timestamp ());
3423 sgen_client_stop_world (generation);
3425 world_is_stopped = TRUE;
3427 if (binary_protocol_is_heavy_enabled ())
3428 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3429 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3432 /* LOCKING: assumes the GC lock is held */
3434 sgen_restart_world (int generation, GGTimingInfo *timing)
3436 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3438 if (binary_protocol_is_enabled ()) {
3439 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3440 if (binary_protocol_is_heavy_enabled ())
3441 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3442 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3445 sgen_client_restart_world (generation, timing);
3447 world_is_stopped = FALSE;
3449 binary_protocol_world_restarted (generation, sgen_timestamp ());
3451 sgen_try_free_some_memory = TRUE;
3453 if (sgen_client_bridge_need_processing ())
3454 sgen_client_bridge_processing_finish (generation);
3456 sgen_memgov_collection_end (generation, timing, timing ? 2 : 0);
3460 sgen_is_world_stopped (void)
3462 return world_is_stopped;
3466 sgen_check_whole_heap_stw (void)
3468 sgen_stop_world (0);
3469 sgen_clear_nursery_fragments ();
3470 sgen_check_whole_heap (FALSE);
3471 sgen_restart_world (0, NULL);
3475 sgen_timestamp (void)
3477 SGEN_TV_DECLARE (timestamp);
3478 SGEN_TV_GETTIME (timestamp);
3479 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3482 #endif /* HAVE_SGEN_GC */