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 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
23 * Important: allocation provides always zeroed memory, having to do
24 * a memset after allocation is deadly for performance.
25 * Memory usage at startup is currently as follows:
27 * 64 KB internal space
29 * We should provide a small memory config with half the sizes
31 * We currently try to make as few mono assumptions as possible:
32 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
34 * 2) gc descriptor is the second word in the vtable (first word in the class)
35 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
36 * 4) there is a function to get an object's size and the number of
37 * elements in an array.
38 * 5) we know the special way bounds are allocated for complex arrays
39 * 6) we know about proxies and how to treat them when domains are unloaded
41 * Always try to keep stack usage to a minimum: no recursive behaviour
42 * and no large stack allocs.
44 * General description.
45 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
46 * When the nursery is full we start a nursery collection: this is performed with a
48 * When the old generation is full we start a copying GC of the old generation as well:
49 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
50 * in the future. Maybe we'll even do both during the same collection like IMMIX.
52 * The things that complicate this description are:
53 * *) pinned objects: we can't move them so we need to keep track of them
54 * *) no precise info of the thread stacks and registers: we need to be able to
55 * quickly find the objects that may be referenced conservatively and pin them
56 * (this makes the first issues more important)
57 * *) large objects are too expensive to be dealt with using copying GC: we handle them
58 * with mark/sweep during major collections
59 * *) some objects need to not move even if they are small (interned strings, Type handles):
60 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
61 * PinnedChunks regions
67 *) we could have a function pointer in MonoClass to implement
68 customized write barriers for value types
70 *) investigate the stuff needed to advance a thread to a GC-safe
71 point (single-stepping, read from unmapped memory etc) and implement it.
72 This would enable us to inline allocations and write barriers, for example,
73 or at least parts of them, like the write barrier checks.
74 We may need this also for handling precise info on stacks, even simple things
75 as having uninitialized data on the stack and having to wait for the prolog
76 to zero it. Not an issue for the last frame that we scan conservatively.
77 We could always not trust the value in the slots anyway.
79 *) modify the jit to save info about references in stack locations:
80 this can be done just for locals as a start, so that at least
81 part of the stack is handled precisely.
83 *) test/fix endianess issues
85 *) Implement a card table as the write barrier instead of remembered
86 sets? Card tables are not easy to implement with our current
87 memory layout. We have several different kinds of major heap
88 objects: Small objects in regular blocks, small objects in pinned
89 chunks and LOS objects. If we just have a pointer we have no way
90 to tell which kind of object it points into, therefore we cannot
91 know where its card table is. The least we have to do to make
92 this happen is to get rid of write barriers for indirect stores.
95 *) Get rid of write barriers for indirect stores. We can do this by
96 telling the GC to wbarrier-register an object once we do an ldloca
97 or ldelema on it, and to unregister it once it's not used anymore
98 (it can only travel downwards on the stack). The problem with
99 unregistering is that it needs to happen eventually no matter
100 what, even if exceptions are thrown, the thread aborts, etc.
101 Rodrigo suggested that we could do only the registering part and
102 let the collector find out (pessimistically) when it's safe to
103 unregister, namely when the stack pointer of the thread that
104 registered the object is higher than it was when the registering
105 happened. This might make for a good first implementation to get
106 some data on performance.
108 *) Some sort of blacklist support? Blacklists is a concept from the
109 Boehm GC: if during a conservative scan we find pointers to an
110 area which we might use as heap, we mark that area as unusable, so
111 pointer retention by random pinning pointers is reduced.
113 *) experiment with max small object size (very small right now - 2kb,
114 because it's tied to the max freelist size)
116 *) add an option to mmap the whole heap in one chunk: it makes for many
117 simplifications in the checks (put the nursery at the top and just use a single
118 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
119 not flexible (too much of the address space may be used by default or we can't
120 increase the heap as needed) and we'd need a race-free mechanism to return memory
121 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
122 was written to, munmap is needed, but the following mmap may not find the same segment
125 *) memzero the major fragments after restarting the world and optionally a smaller
128 *) investigate having fragment zeroing threads
130 *) separate locks for finalization and other minor stuff to reduce
133 *) try a different copying order to improve memory locality
135 *) a thread abort after a store but before the write barrier will
136 prevent the write barrier from executing
138 *) specialized dynamically generated markers/copiers
140 *) Dynamically adjust TLAB size to the number of threads. If we have
141 too many threads that do allocation, we might need smaller TLABs,
142 and we might get better performance with larger TLABs if we only
143 have a handful of threads. We could sum up the space left in all
144 assigned TLABs and if that's more than some percentage of the
145 nursery size, reduce the TLAB size.
147 *) Explore placing unreachable objects on unused nursery memory.
148 Instead of memset'ng a region to zero, place an int[] covering it.
149 A good place to start is add_nursery_frag. The tricky thing here is
150 placing those objects atomically outside of a collection.
152 *) Allocation should use asymmetric Dekker synchronization:
153 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
154 This should help weak consistency archs.
161 #define _XOPEN_SOURCE
162 #define _DARWIN_C_SOURCE
168 #ifdef HAVE_PTHREAD_H
171 #ifdef HAVE_PTHREAD_NP_H
172 #include <pthread_np.h>
180 #include "mono/sgen/sgen-gc.h"
181 #include "mono/sgen/sgen-cardtable.h"
182 #include "mono/sgen/sgen-protocol.h"
183 #include "mono/sgen/sgen-memory-governor.h"
184 #include "mono/sgen/sgen-hash-table.h"
185 #include "mono/sgen/sgen-cardtable.h"
186 #include "mono/sgen/sgen-pinning.h"
187 #include "mono/sgen/sgen-workers.h"
188 #include "mono/sgen/sgen-client.h"
189 #include "mono/sgen/sgen-pointer-queue.h"
190 #include "mono/sgen/gc-internal-agnostic.h"
191 #include "mono/utils/mono-proclib.h"
192 #include "mono/utils/mono-memory-model.h"
193 #include "mono/utils/hazard-pointer.h"
195 #include <mono/utils/memcheck.h>
197 #undef pthread_create
199 #undef pthread_detach
202 * ######################################################################
203 * ######## Types and constants used by the GC.
204 * ######################################################################
207 /* 0 means not initialized, 1 is initialized, -1 means in progress */
208 static int gc_initialized = 0;
209 /* If set, check if we need to do something every X allocations */
210 gboolean has_per_allocation_action;
211 /* If set, do a heap check every X allocation */
212 guint32 verify_before_allocs = 0;
213 /* If set, do a minor collection before every X allocation */
214 guint32 collect_before_allocs = 0;
215 /* If set, do a whole heap check before each collection */
216 static gboolean whole_heap_check_before_collection = FALSE;
217 /* If set, do a remset consistency check at various opportunities */
218 static gboolean remset_consistency_checks = FALSE;
219 /* If set, do a mod union consistency check before each finishing collection pause */
220 static gboolean mod_union_consistency_check = FALSE;
221 /* If set, check whether mark bits are consistent after major collections */
222 static gboolean check_mark_bits_after_major_collection = FALSE;
223 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
224 static gboolean check_nursery_objects_pinned = FALSE;
225 /* If set, do a few checks when the concurrent collector is used */
226 static gboolean do_concurrent_checks = FALSE;
227 /* If set, do a plausibility check on the scan_starts before and after
229 static gboolean do_scan_starts_check = FALSE;
231 static gboolean disable_minor_collections = FALSE;
232 static gboolean disable_major_collections = FALSE;
233 static gboolean do_verify_nursery = FALSE;
234 static gboolean do_dump_nursery_content = FALSE;
235 static gboolean enable_nursery_canaries = FALSE;
237 static gboolean precleaning_enabled = TRUE;
239 #ifdef HEAVY_STATISTICS
240 guint64 stat_objects_alloced_degraded = 0;
241 guint64 stat_bytes_alloced_degraded = 0;
243 guint64 stat_copy_object_called_nursery = 0;
244 guint64 stat_objects_copied_nursery = 0;
245 guint64 stat_copy_object_called_major = 0;
246 guint64 stat_objects_copied_major = 0;
248 guint64 stat_scan_object_called_nursery = 0;
249 guint64 stat_scan_object_called_major = 0;
251 guint64 stat_slots_allocated_in_vain;
253 guint64 stat_nursery_copy_object_failed_from_space = 0;
254 guint64 stat_nursery_copy_object_failed_forwarded = 0;
255 guint64 stat_nursery_copy_object_failed_pinned = 0;
256 guint64 stat_nursery_copy_object_failed_to_space = 0;
258 static guint64 stat_wbarrier_add_to_global_remset = 0;
259 static guint64 stat_wbarrier_arrayref_copy = 0;
260 static guint64 stat_wbarrier_generic_store = 0;
261 static guint64 stat_wbarrier_generic_store_atomic = 0;
262 static guint64 stat_wbarrier_set_root = 0;
265 static guint64 stat_pinned_objects = 0;
267 static guint64 time_minor_pre_collection_fragment_clear = 0;
268 static guint64 time_minor_pinning = 0;
269 static guint64 time_minor_scan_remsets = 0;
270 static guint64 time_minor_scan_pinned = 0;
271 static guint64 time_minor_scan_roots = 0;
272 static guint64 time_minor_finish_gray_stack = 0;
273 static guint64 time_minor_fragment_creation = 0;
275 static guint64 time_major_pre_collection_fragment_clear = 0;
276 static guint64 time_major_pinning = 0;
277 static guint64 time_major_scan_pinned = 0;
278 static guint64 time_major_scan_roots = 0;
279 static guint64 time_major_scan_mod_union = 0;
280 static guint64 time_major_finish_gray_stack = 0;
281 static guint64 time_major_free_bigobjs = 0;
282 static guint64 time_major_los_sweep = 0;
283 static guint64 time_major_sweep = 0;
284 static guint64 time_major_fragment_creation = 0;
286 static guint64 time_max = 0;
288 static SGEN_TV_DECLARE (time_major_conc_collection_start);
289 static SGEN_TV_DECLARE (time_major_conc_collection_end);
291 int gc_debug_level = 0;
293 static char* gc_params_options;
294 static char* gc_debug_options;
298 mono_gc_flush_info (void)
300 fflush (gc_debug_file);
304 #define TV_DECLARE SGEN_TV_DECLARE
305 #define TV_GETTIME SGEN_TV_GETTIME
306 #define TV_ELAPSED SGEN_TV_ELAPSED
308 static SGEN_TV_DECLARE (sgen_init_timestamp);
310 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
312 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
313 #define object_is_pinned SGEN_OBJECT_IS_PINNED
314 #define pin_object SGEN_PIN_OBJECT
316 #define ptr_in_nursery sgen_ptr_in_nursery
318 #define LOAD_VTABLE SGEN_LOAD_VTABLE
321 nursery_canaries_enabled (void)
323 return enable_nursery_canaries;
326 #define safe_object_get_size sgen_safe_object_get_size
328 #if defined(HAVE_CONC_GC_AS_DEFAULT)
329 /* Use concurrent major on deskstop platforms */
330 #define DEFAULT_MAJOR_INIT sgen_marksweep_conc_init
331 #define DEFAULT_MAJOR_NAME "marksweep-conc"
333 #define DEFAULT_MAJOR_INIT sgen_marksweep_init
334 #define DEFAULT_MAJOR_NAME "marksweep"
338 * ######################################################################
339 * ######## Global data.
340 * ######################################################################
342 MonoCoopMutex gc_mutex;
344 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
346 size_t degraded_mode = 0;
348 static mword bytes_pinned_from_failed_allocation = 0;
350 GCMemSection *nursery_section = NULL;
351 static volatile mword lowest_heap_address = ~(mword)0;
352 static volatile mword highest_heap_address = 0;
354 MonoCoopMutex sgen_interruption_mutex;
356 int current_collection_generation = -1;
357 static volatile gboolean concurrent_collection_in_progress = FALSE;
359 /* objects that are ready to be finalized */
360 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
361 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
363 /* registered roots: the key to the hash is the root start address */
365 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
367 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
368 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
369 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
370 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
372 static mword roots_size = 0; /* amount of memory in the root set */
374 /* The size of a TLAB */
375 /* The bigger the value, the less often we have to go to the slow path to allocate a new
376 * one, but the more space is wasted by threads not allocating much memory.
378 * FIXME: Make this self-tuning for each thread.
380 guint32 tlab_size = (1024 * 4);
382 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
384 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
386 #define ALIGN_UP SGEN_ALIGN_UP
388 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
389 MonoNativeThreadId main_gc_thread = NULL;
392 /*Object was pinned during the current collection*/
393 static mword objects_pinned;
396 * ######################################################################
397 * ######## Macros and function declarations.
398 * ######################################################################
401 /* forward declarations */
402 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
404 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
405 static void finish_gray_stack (int generation, ScanCopyContext ctx);
408 SgenMajorCollector major_collector;
409 SgenMinorCollector sgen_minor_collector;
411 static SgenRememberedSet remset;
414 * The gray queue a worker job must use. If we're not parallel or
415 * concurrent, we use the main gray queue.
417 static SgenGrayQueue*
418 sgen_workers_get_job_gray_queue (WorkerData *worker_data, SgenGrayQueue *default_gray_queue)
421 return &worker_data->private_gray_queue;
422 SGEN_ASSERT (0, default_gray_queue, "Why don't we have a default gray queue when we're not running in a worker thread?");
423 return default_gray_queue;
427 gray_queue_redirect (SgenGrayQueue *queue)
429 SGEN_ASSERT (0, concurrent_collection_in_progress, "Where are we redirecting the gray queue to, without a concurrent collection?");
431 sgen_workers_take_from_queue (queue);
435 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries)
437 while (start < end) {
441 if (!*(void**)start) {
442 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
447 if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
453 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
454 CHECK_CANARY_FOR_OBJECT ((GCObject*)obj, fail_on_canaries);
455 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
456 callback ((GCObject*)obj, size, data);
457 CANARIFY_SIZE (size);
459 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
467 * sgen_add_to_global_remset:
469 * The global remset contains locations which point into newspace after
470 * a minor collection. This can happen if the objects they point to are pinned.
472 * LOCKING: If called from a parallel collector, the global remset
473 * lock must be held. For serial collectors that is not necessary.
476 sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
478 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
480 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
482 if (!major_collector.is_concurrent) {
483 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
485 if (current_collection_generation == -1)
486 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
489 if (!object_is_pinned (obj))
490 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");
491 else if (sgen_cement_lookup_or_register (obj))
494 remset.record_pointer (ptr);
496 sgen_pin_stats_register_global_remset (obj);
498 SGEN_LOG (8, "Adding global remset for %p", ptr);
499 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
503 * sgen_drain_gray_stack:
505 * Scan objects in the gray stack until the stack is empty. This should be called
506 * frequently after each object is copied, to achieve better locality and cache
511 sgen_drain_gray_stack (ScanCopyContext ctx)
513 ScanObjectFunc scan_func = ctx.ops->scan_object;
514 SgenGrayQueue *queue = ctx.queue;
516 if (ctx.ops->drain_gray_stack)
517 return ctx.ops->drain_gray_stack (queue);
522 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
525 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
526 scan_func (obj, desc, queue);
532 * Addresses in the pin queue are already sorted. This function finds
533 * the object header for each address and pins the object. The
534 * addresses must be inside the nursery section. The (start of the)
535 * address array is overwritten with the addresses of the actually
536 * pinned objects. Return the number of pinned objects.
539 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
541 GCMemSection *section = nursery_section;
542 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
543 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
544 void *start_nursery = section->data;
545 void *end_nursery = section->next_data;
550 void *pinning_front = start_nursery;
552 void **definitely_pinned = start;
553 ScanObjectFunc scan_func = ctx.ops->scan_object;
554 SgenGrayQueue *queue = ctx.queue;
556 sgen_nursery_allocator_prepare_for_pinning ();
558 while (start < end) {
559 GCObject *obj_to_pin = NULL;
560 size_t obj_to_pin_size = 0;
565 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
566 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
573 SGEN_LOG (5, "Considering pinning addr %p", addr);
574 /* We've already processed everything up to pinning_front. */
575 if (addr < pinning_front) {
581 * Find the closest scan start <= addr. We might search backward in the
582 * scan_starts array because entries might be NULL. In the worst case we
583 * start at start_nursery.
585 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
586 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
587 search_start = (void*)section->scan_starts [idx];
588 if (!search_start || search_start > addr) {
591 search_start = section->scan_starts [idx];
592 if (search_start && search_start <= addr)
595 if (!search_start || search_start > addr)
596 search_start = start_nursery;
600 * If the pinning front is closer than the scan start we found, start
601 * searching at the front.
603 if (search_start < pinning_front)
604 search_start = pinning_front;
607 * Now addr should be in an object a short distance from search_start.
609 * search_start must point to zeroed mem or point to an object.
612 size_t obj_size, canarified_obj_size;
615 if (!*(void**)search_start) {
616 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
617 /* The loop condition makes sure we don't overrun addr. */
621 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
624 * Filler arrays are marked by an invalid sync word. We don't
625 * consider them for pinning. They are not delimited by canaries,
628 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
629 CHECK_CANARY_FOR_OBJECT (search_start, TRUE);
630 CANARIFY_SIZE (canarified_obj_size);
632 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
633 /* This is the object we're looking for. */
634 obj_to_pin = (GCObject*)search_start;
635 obj_to_pin_size = canarified_obj_size;
640 /* Skip to the next object */
641 search_start = (void*)((char*)search_start + canarified_obj_size);
642 } while (search_start <= addr);
644 /* We've searched past the address we were looking for. */
646 pinning_front = search_start;
647 goto next_pin_queue_entry;
651 * We've found an object to pin. It might still be a dummy array, but we
652 * can advance the pinning front in any case.
654 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
657 * If this is a dummy array marking the beginning of a nursery
658 * fragment, we don't pin it.
660 if (sgen_client_object_is_array_fill (obj_to_pin))
661 goto next_pin_queue_entry;
664 * Finally - pin the object!
666 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
667 if (do_scan_objects) {
668 scan_func (obj_to_pin, desc, queue);
670 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
671 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
672 binary_protocol_pin (obj_to_pin,
673 (gpointer)LOAD_VTABLE (obj_to_pin),
674 safe_object_get_size (obj_to_pin));
676 pin_object (obj_to_pin);
677 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
678 sgen_pin_stats_register_object (obj_to_pin, GENERATION_NURSERY);
679 definitely_pinned [count] = obj_to_pin;
682 if (concurrent_collection_in_progress)
683 sgen_pinning_register_pinned_in_nursery (obj_to_pin);
685 next_pin_queue_entry:
689 sgen_client_nursery_objects_pinned (definitely_pinned, count);
690 stat_pinned_objects += count;
695 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
699 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
702 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
703 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
707 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
708 * when we can't promote an object because we're out of memory.
711 sgen_pin_object (GCObject *object, SgenGrayQueue *queue)
713 SGEN_ASSERT (0, sgen_ptr_in_nursery (object), "We're only supposed to use this for pinning nursery objects when out of memory.");
716 * All pinned objects are assumed to have been staged, so we need to stage as well.
717 * Also, the count of staged objects shows that "late pinning" happened.
719 sgen_pin_stage_ptr (object);
721 SGEN_PIN_OBJECT (object);
722 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
725 sgen_pin_stats_register_object (object, GENERATION_NURSERY);
727 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
730 /* Sort the addresses in array in increasing order.
731 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
734 sgen_sort_addresses (void **array, size_t size)
739 for (i = 1; i < size; ++i) {
742 size_t parent = (child - 1) / 2;
744 if (array [parent] >= array [child])
747 tmp = array [parent];
748 array [parent] = array [child];
755 for (i = size - 1; i > 0; --i) {
758 array [i] = array [0];
764 while (root * 2 + 1 <= end) {
765 size_t child = root * 2 + 1;
767 if (child < end && array [child] < array [child + 1])
769 if (array [root] >= array [child])
773 array [root] = array [child];
782 * Scan the memory between start and end and queue values which could be pointers
783 * to the area between start_nursery and end_nursery for later consideration.
784 * Typically used for thread stacks.
787 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
791 SGEN_ASSERT (0, ((mword)start & (SIZEOF_VOID_P - 1)) == 0, "Why are we scanning for references in unaligned memory ?");
793 #if defined(VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE) && !defined(_WIN64)
794 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
797 while (start < end) {
799 * *start can point to the middle of an object
800 * note: should we handle pointing at the end of an object?
801 * pinning in C# code disallows pointing at the end of an object
802 * but there is some small chance that an optimizing C compiler
803 * may keep the only reference to an object by pointing
804 * at the end of it. We ignore this small chance for now.
805 * Pointers to the end of an object are indistinguishable
806 * from pointers to the start of the next object in memory
807 * so if we allow that we'd need to pin two objects...
808 * We queue the pointer in an array, the
809 * array will then be sorted and uniqued. This way
810 * we can coalesce several pinning pointers and it should
811 * be faster since we'd do a memory scan with increasing
812 * addresses. Note: we can align the address to the allocation
813 * alignment, so the unique process is more effective.
815 mword addr = (mword)*start;
816 addr &= ~(ALLOC_ALIGN - 1);
817 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
818 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
819 sgen_pin_stage_ptr ((void*)addr);
820 binary_protocol_pin_stage (start, (void*)addr);
821 sgen_pin_stats_register_address ((char*)addr, pin_type);
827 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
831 * The first thing we do in a collection is to identify pinned objects.
832 * This function considers all the areas of memory that need to be
833 * conservatively scanned.
836 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
840 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);
841 /* objects pinned from the API are inside these roots */
842 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
843 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
844 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
845 } SGEN_HASH_TABLE_FOREACH_END;
846 /* now deal with the thread stacks
847 * in the future we should be able to conservatively scan only:
848 * *) the cpu registers
849 * *) the unmanaged stack frames
850 * *) the _last_ managed stack frame
851 * *) pointers slots in managed frames
853 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
857 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
859 ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
860 ctx->ops->copy_or_mark_object (obj, ctx->queue);
864 * The memory area from start_root to end_root contains pointers to objects.
865 * Their position is precisely described by @desc (this means that the pointer
866 * can be either NULL or the pointer to the start of an object).
867 * This functions copies them to to_space updates them.
869 * This function is not thread-safe!
872 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, SgenDescriptor desc, ScanCopyContext ctx)
874 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
875 SgenGrayQueue *queue = ctx.queue;
877 switch (desc & ROOT_DESC_TYPE_MASK) {
878 case ROOT_DESC_BITMAP:
879 desc >>= ROOT_DESC_TYPE_SHIFT;
881 if ((desc & 1) && *start_root) {
882 copy_func ((GCObject**)start_root, queue);
883 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
889 case ROOT_DESC_COMPLEX: {
890 gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
891 gsize bwords = (*bitmap_data) - 1;
892 void **start_run = start_root;
894 while (bwords-- > 0) {
895 gsize bmap = *bitmap_data++;
896 void **objptr = start_run;
898 if ((bmap & 1) && *objptr) {
899 copy_func ((GCObject**)objptr, queue);
900 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
905 start_run += GC_BITS_PER_WORD;
909 case ROOT_DESC_USER: {
910 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
911 marker (start_root, single_arg_user_copy_or_mark, &ctx);
914 case ROOT_DESC_RUN_LEN:
915 g_assert_not_reached ();
917 g_assert_not_reached ();
922 reset_heap_boundaries (void)
924 lowest_heap_address = ~(mword)0;
925 highest_heap_address = 0;
929 sgen_update_heap_boundaries (mword low, mword high)
934 old = lowest_heap_address;
937 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
940 old = highest_heap_address;
943 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
947 * Allocate and setup the data structures needed to be able to allocate objects
948 * in the nursery. The nursery is stored in nursery_section.
953 GCMemSection *section;
960 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
961 /* later we will alloc a larger area for the nursery but only activate
962 * what we need. The rest will be used as expansion if we have too many pinned
963 * objects in the existing nursery.
965 /* FIXME: handle OOM */
966 section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
968 alloc_size = sgen_nursery_size;
970 /* If there isn't enough space even for the nursery we should simply abort. */
971 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
973 data = (char *)major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
974 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
975 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 ());
976 section->data = section->next_data = data;
977 section->size = alloc_size;
978 section->end_data = data + sgen_nursery_size;
979 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
980 section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
981 section->num_scan_start = scan_starts;
983 nursery_section = section;
985 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
989 mono_gc_get_logfile (void)
991 return gc_debug_file;
995 mono_gc_params_set (const char* options)
997 if (gc_params_options)
998 g_free (gc_params_options);
1000 gc_params_options = g_strdup (options);
1004 mono_gc_debug_set (const char* options)
1006 if (gc_debug_options)
1007 g_free (gc_debug_options);
1009 gc_debug_options = g_strdup (options);
1013 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1015 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1016 SgenGrayQueue *queue = ctx.queue;
1019 for (i = 0; i < fin_queue->next_slot; ++i) {
1020 GCObject *obj = (GCObject *)fin_queue->data [i];
1023 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1024 copy_func ((GCObject**)&fin_queue->data [i], queue);
1029 generation_name (int generation)
1031 switch (generation) {
1032 case GENERATION_NURSERY: return "nursery";
1033 case GENERATION_OLD: return "old";
1034 default: g_assert_not_reached ();
1039 sgen_generation_name (int generation)
1041 return generation_name (generation);
1045 finish_gray_stack (int generation, ScanCopyContext ctx)
1049 int done_with_ephemerons, ephemeron_rounds = 0;
1050 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1051 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1052 SgenGrayQueue *queue = ctx.queue;
1054 binary_protocol_finish_gray_stack_start (sgen_timestamp (), generation);
1056 * We copied all the reachable objects. Now it's the time to copy
1057 * the objects that were not referenced by the roots, but by the copied objects.
1058 * we built a stack of objects pointed to by gray_start: they are
1059 * additional roots and we may add more items as we go.
1060 * We loop until gray_start == gray_objects which means no more objects have
1061 * been added. Note this is iterative: no recursion is involved.
1062 * We need to walk the LO list as well in search of marked big objects
1063 * (use a flag since this is needed only on major collections). We need to loop
1064 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1065 * To achieve better cache locality and cache usage, we drain the gray stack
1066 * frequently, after each object is copied, and just finish the work here.
1068 sgen_drain_gray_stack (ctx);
1070 SGEN_LOG (2, "%s generation done", generation_name (generation));
1073 Reset bridge data, we might have lingering data from a previous collection if this is a major
1074 collection trigged by minor overflow.
1076 We must reset the gathered bridges since their original block might be evacuated due to major
1077 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1079 if (sgen_client_bridge_need_processing ())
1080 sgen_client_bridge_reset_data ();
1083 * Mark all strong toggleref objects. This must be done before we walk ephemerons or finalizers
1084 * to ensure they see the full set of live objects.
1086 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1089 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1090 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1091 * objects that are in fact reachable.
1093 done_with_ephemerons = 0;
1095 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1096 sgen_drain_gray_stack (ctx);
1098 } while (!done_with_ephemerons);
1100 if (sgen_client_bridge_need_processing ()) {
1101 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1102 sgen_drain_gray_stack (ctx);
1103 sgen_collect_bridge_objects (generation, ctx);
1104 if (generation == GENERATION_OLD)
1105 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1108 Do the first bridge step here, as the collector liveness state will become useless after that.
1110 An important optimization is to only proccess the possibly dead part of the object graph and skip
1111 over all live objects as we transitively know everything they point must be alive too.
1113 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1115 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1116 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1119 sgen_client_bridge_processing_stw_step ();
1123 Make sure we drain the gray stack before processing disappearing links and finalizers.
1124 If we don't make sure it is empty we might wrongly see a live object as dead.
1126 sgen_drain_gray_stack (ctx);
1129 We must clear weak links that don't track resurrection before processing object ready for
1130 finalization so they can be cleared before that.
1132 sgen_null_link_in_range (generation, ctx, FALSE);
1133 if (generation == GENERATION_OLD)
1134 sgen_null_link_in_range (GENERATION_NURSERY, ctx, FALSE);
1137 /* walk the finalization queue and move also the objects that need to be
1138 * finalized: use the finalized objects as new roots so the objects they depend
1139 * on are also not reclaimed. As with the roots above, only objects in the nursery
1140 * are marked/copied.
1142 sgen_finalize_in_range (generation, ctx);
1143 if (generation == GENERATION_OLD)
1144 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1145 /* drain the new stack that might have been created */
1146 SGEN_LOG (6, "Precise scan of gray area post fin");
1147 sgen_drain_gray_stack (ctx);
1150 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1152 done_with_ephemerons = 0;
1154 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1155 sgen_drain_gray_stack (ctx);
1157 } while (!done_with_ephemerons);
1159 sgen_client_clear_unreachable_ephemerons (ctx);
1162 * We clear togglerefs only after all possible chances of revival are done.
1163 * This is semantically more inline with what users expect and it allows for
1164 * user finalizers to correctly interact with TR objects.
1166 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1169 SGEN_LOG (2, "Finalize queue handling scan for %s generation: %lld usecs %d ephemeron rounds", generation_name (generation), (long long)TV_ELAPSED (atv, btv), ephemeron_rounds);
1172 * handle disappearing links
1173 * Note we do this after checking the finalization queue because if an object
1174 * survives (at least long enough to be finalized) we don't clear the link.
1175 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1176 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1179 g_assert (sgen_gray_object_queue_is_empty (queue));
1181 sgen_null_link_in_range (generation, ctx, TRUE);
1182 if (generation == GENERATION_OLD)
1183 sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
1184 if (sgen_gray_object_queue_is_empty (queue))
1186 sgen_drain_gray_stack (ctx);
1189 g_assert (sgen_gray_object_queue_is_empty (queue));
1191 binary_protocol_finish_gray_stack_end (sgen_timestamp (), generation);
1195 sgen_check_section_scan_starts (GCMemSection *section)
1198 for (i = 0; i < section->num_scan_start; ++i) {
1199 if (section->scan_starts [i]) {
1200 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1201 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1207 check_scan_starts (void)
1209 if (!do_scan_starts_check)
1211 sgen_check_section_scan_starts (nursery_section);
1212 major_collector.check_scan_starts ();
1216 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1220 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
1221 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1222 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1223 } SGEN_HASH_TABLE_FOREACH_END;
1229 static gboolean inited = FALSE;
1234 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1236 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1237 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1238 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1239 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1240 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1241 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1243 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1244 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1245 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1246 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1247 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1248 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1249 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1250 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1251 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1252 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1254 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1256 #ifdef HEAVY_STATISTICS
1257 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1258 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1259 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1260 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1261 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1263 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1264 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1266 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1267 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1268 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1269 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1271 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1272 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1274 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1276 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1277 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1278 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1279 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1281 sgen_nursery_allocator_init_heavy_stats ();
1289 reset_pinned_from_failed_allocation (void)
1291 bytes_pinned_from_failed_allocation = 0;
1295 sgen_set_pinned_from_failed_allocation (mword objsize)
1297 bytes_pinned_from_failed_allocation += objsize;
1301 sgen_collection_is_concurrent (void)
1303 switch (current_collection_generation) {
1304 case GENERATION_NURSERY:
1306 case GENERATION_OLD:
1307 return concurrent_collection_in_progress;
1309 g_error ("Invalid current generation %d", current_collection_generation);
1315 sgen_concurrent_collection_in_progress (void)
1317 return concurrent_collection_in_progress;
1321 SgenThreadPoolJob job;
1322 SgenObjectOperations *ops;
1323 SgenGrayQueue *gc_thread_gray_queue;
1331 static ScanCopyContext
1332 scan_copy_context_for_scan_job (void *worker_data_untyped, ScanJob *job)
1334 WorkerData *worker_data = (WorkerData *)worker_data_untyped;
1336 return CONTEXT_FROM_OBJECT_OPERATIONS (job->ops, sgen_workers_get_job_gray_queue (worker_data, job->gc_thread_gray_queue));
1340 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
1342 remset.scan_remsets (scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job));
1350 } ScanFromRegisteredRootsJob;
1353 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1355 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1356 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1358 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1365 } ScanThreadDataJob;
1368 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1370 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1371 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1373 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1378 SgenPointerQueue *queue;
1379 } ScanFinalizerEntriesJob;
1382 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1384 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1385 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1387 scan_finalizer_entries (job_data->queue, ctx);
1391 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1393 ScanJob *job_data = (ScanJob*)job;
1394 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1396 g_assert (concurrent_collection_in_progress);
1397 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, 0, 1);
1401 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1403 ScanJob *job_data = (ScanJob*)job;
1404 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1406 g_assert (concurrent_collection_in_progress);
1407 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, 0, 1);
1411 job_major_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1413 ParallelScanJob *job_data = (ParallelScanJob*)job;
1414 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1416 g_assert (concurrent_collection_in_progress);
1418 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1422 job_los_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1424 ParallelScanJob *job_data = (ParallelScanJob*)job;
1425 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1427 g_assert (concurrent_collection_in_progress);
1429 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1433 job_scan_last_pinned (void *worker_data_untyped, SgenThreadPoolJob *job)
1435 ScanJob *job_data = (ScanJob*)job;
1436 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1438 g_assert (concurrent_collection_in_progress);
1440 sgen_scan_pin_queue_objects (ctx);
1444 workers_finish_callback (void)
1446 ParallelScanJob *psj;
1448 int split_count = sgen_workers_get_job_split_count ();
1450 /* Mod union preclean jobs */
1451 for (i = 0; i < split_count; i++) {
1452 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean major mod union cardtable", job_major_mod_union_preclean, sizeof (ParallelScanJob));
1453 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1454 psj->scan_job.gc_thread_gray_queue = NULL;
1456 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1459 for (i = 0; i < split_count; i++) {
1460 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean los mod union cardtable", job_los_mod_union_preclean, sizeof (ParallelScanJob));
1461 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1462 psj->scan_job.gc_thread_gray_queue = NULL;
1464 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1467 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan last pinned", job_scan_last_pinned, sizeof (ScanJob));
1468 sj->ops = sgen_workers_get_idle_func_object_ops ();
1469 sj->gc_thread_gray_queue = NULL;
1470 sgen_workers_enqueue_job (&sj->job, TRUE);
1474 init_gray_queue (SgenGrayQueue *gc_thread_gray_queue, gboolean use_workers)
1477 sgen_workers_init_distribute_gray_queue ();
1478 sgen_gray_object_queue_init (gc_thread_gray_queue, NULL, TRUE);
1482 enqueue_scan_from_roots_jobs (SgenGrayQueue *gc_thread_gray_queue, char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
1484 ScanFromRegisteredRootsJob *scrrj;
1485 ScanThreadDataJob *stdj;
1486 ScanFinalizerEntriesJob *sfej;
1488 /* registered roots, this includes static fields */
1490 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1491 scrrj->scan_job.ops = ops;
1492 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1493 scrrj->heap_start = heap_start;
1494 scrrj->heap_end = heap_end;
1495 scrrj->root_type = ROOT_TYPE_NORMAL;
1496 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1498 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1499 scrrj->scan_job.ops = ops;
1500 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1501 scrrj->heap_start = heap_start;
1502 scrrj->heap_end = heap_end;
1503 scrrj->root_type = ROOT_TYPE_WBARRIER;
1504 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1508 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1509 stdj->scan_job.ops = ops;
1510 stdj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1511 stdj->heap_start = heap_start;
1512 stdj->heap_end = heap_end;
1513 sgen_workers_enqueue_job (&stdj->scan_job.job, enqueue);
1515 /* Scan the list of objects ready for finalization. */
1517 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1518 sfej->scan_job.ops = ops;
1519 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1520 sfej->queue = &fin_ready_queue;
1521 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1523 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1524 sfej->scan_job.ops = ops;
1525 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1526 sfej->queue = &critical_fin_queue;
1527 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1531 * Perform a nursery collection.
1533 * Return whether any objects were late-pinned due to being out of memory.
1536 collect_nursery (const char *reason, gboolean is_overflow, SgenGrayQueue *unpin_queue)
1538 gboolean needs_major;
1539 size_t max_garbage_amount;
1541 mword fragment_total;
1543 SgenGrayQueue gc_thread_gray_queue;
1544 SgenObjectOperations *object_ops;
1545 ScanCopyContext ctx;
1548 SGEN_TV_DECLARE (last_minor_collection_start_tv);
1549 SGEN_TV_DECLARE (last_minor_collection_end_tv);
1551 if (disable_minor_collections)
1554 TV_GETTIME (last_minor_collection_start_tv);
1555 atv = last_minor_collection_start_tv;
1557 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1559 if (sgen_concurrent_collection_in_progress ())
1560 object_ops = &sgen_minor_collector.serial_ops_with_concurrent_major;
1562 object_ops = &sgen_minor_collector.serial_ops;
1564 if (do_verify_nursery || do_dump_nursery_content)
1565 sgen_debug_verify_nursery (do_dump_nursery_content);
1567 current_collection_generation = GENERATION_NURSERY;
1569 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1571 reset_pinned_from_failed_allocation ();
1573 check_scan_starts ();
1575 sgen_nursery_alloc_prepare_for_minor ();
1579 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
1580 /* FIXME: optimize later to use the higher address where an object can be present */
1581 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
1583 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 ()));
1584 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
1585 g_assert (nursery_section->size >= max_garbage_amount);
1587 /* world must be stopped already */
1589 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1591 sgen_client_pre_collection_checks ();
1593 nursery_section->next_data = nursery_next;
1595 major_collector.start_nursery_collection ();
1597 sgen_memgov_minor_collection_start ();
1599 init_gray_queue (&gc_thread_gray_queue, FALSE);
1600 ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gc_thread_gray_queue);
1602 gc_stats.minor_gc_count ++;
1604 sgen_process_fin_stage_entries ();
1606 /* pin from pinned handles */
1607 sgen_init_pinning ();
1608 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1609 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
1610 /* pin cemented objects */
1611 sgen_pin_cemented_objects ();
1612 /* identify pinned objects */
1613 sgen_optimize_pin_queue ();
1614 sgen_pinning_setup_section (nursery_section);
1616 pin_objects_in_nursery (FALSE, ctx);
1617 sgen_pinning_trim_queue_to_section (nursery_section);
1619 if (remset_consistency_checks)
1620 sgen_check_remset_consistency ();
1622 if (whole_heap_check_before_collection) {
1623 sgen_clear_nursery_fragments ();
1624 sgen_check_whole_heap (FALSE);
1628 time_minor_pinning += TV_ELAPSED (btv, atv);
1629 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (btv, atv));
1630 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1632 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
1633 sj->ops = object_ops;
1634 sj->gc_thread_gray_queue = &gc_thread_gray_queue;
1635 sgen_workers_enqueue_job (&sj->job, FALSE);
1637 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1639 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1640 SGEN_LOG (2, "Old generation scan: %lld usecs", (long long)TV_ELAPSED (atv, btv));
1642 sgen_pin_stats_report ();
1644 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1645 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1648 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1650 enqueue_scan_from_roots_jobs (&gc_thread_gray_queue, sgen_get_nursery_start (), nursery_next, object_ops, FALSE);
1653 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1655 finish_gray_stack (GENERATION_NURSERY, ctx);
1658 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1659 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1661 if (objects_pinned) {
1662 sgen_optimize_pin_queue ();
1663 sgen_pinning_setup_section (nursery_section);
1667 * This is the latest point at which we can do this check, because
1668 * sgen_build_nursery_fragments() unpins nursery objects again.
1670 if (remset_consistency_checks)
1671 sgen_check_remset_consistency ();
1673 /* walk the pin_queue, build up the fragment list of free memory, unmark
1674 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1677 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1678 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1679 if (!fragment_total)
1682 /* Clear TLABs for all threads */
1683 sgen_clear_tlabs ();
1685 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1687 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1688 SGEN_LOG (2, "Fragment creation: %lld usecs, %lu bytes available", (long long)TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1690 if (remset_consistency_checks)
1691 sgen_check_major_refs ();
1693 major_collector.finish_nursery_collection ();
1695 TV_GETTIME (last_minor_collection_end_tv);
1696 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1698 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1700 /* prepare the pin queue for the next collection */
1701 sgen_finish_pinning ();
1702 if (sgen_have_pending_finalizers ()) {
1703 SGEN_LOG (4, "Finalizer-thread wakeup");
1704 sgen_client_finalize_notify ();
1706 sgen_pin_stats_reset ();
1707 /* clear cemented hash */
1708 sgen_cement_clear_below_threshold ();
1710 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
1712 remset.finish_minor_collection ();
1714 check_scan_starts ();
1716 binary_protocol_flush_buffers (FALSE);
1718 sgen_memgov_minor_collection_end (reason, is_overflow);
1720 /*objects are late pinned because of lack of memory, so a major is a good call*/
1721 needs_major = objects_pinned > 0;
1722 current_collection_generation = -1;
1725 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1727 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1728 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1734 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1735 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1736 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1737 } CopyOrMarkFromRootsMode;
1740 major_copy_or_mark_from_roots (SgenGrayQueue *gc_thread_gray_queue, size_t *old_next_pin_slot, CopyOrMarkFromRootsMode mode, SgenObjectOperations *object_ops)
1745 /* FIXME: only use these values for the precise scan
1746 * note that to_space pointers should be excluded anyway...
1748 char *heap_start = NULL;
1749 char *heap_end = (char*)-1;
1750 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, gc_thread_gray_queue);
1751 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1753 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1755 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1756 /*This cleans up unused fragments */
1757 sgen_nursery_allocator_prepare_for_pinning ();
1759 if (do_concurrent_checks)
1760 sgen_debug_check_nursery_is_clean ();
1762 /* The concurrent collector doesn't touch the nursery. */
1763 sgen_nursery_alloc_prepare_for_major ();
1768 /* Pinning depends on this */
1769 sgen_clear_nursery_fragments ();
1771 if (whole_heap_check_before_collection)
1772 sgen_check_whole_heap (TRUE);
1775 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1777 if (!sgen_collection_is_concurrent ())
1778 nursery_section->next_data = sgen_get_nursery_end ();
1779 /* we should also coalesce scanning from sections close to each other
1780 * and deal with pointers outside of the sections later.
1785 sgen_client_pre_collection_checks ();
1787 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1788 /* Remsets are not useful for a major collection */
1789 remset.clear_cards ();
1792 sgen_process_fin_stage_entries ();
1795 sgen_init_pinning ();
1796 SGEN_LOG (6, "Collecting pinned addresses");
1797 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1798 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1799 /* Pin cemented objects that were forced */
1800 sgen_pin_cemented_objects ();
1802 sgen_optimize_pin_queue ();
1803 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1805 * Cemented objects that are in the pinned list will be marked. When
1806 * marking concurrently we won't mark mod-union cards for these objects.
1807 * Instead they will remain cemented until the next major collection,
1808 * when we will recheck if they are still pinned in the roots.
1810 sgen_cement_force_pinned ();
1813 sgen_client_collecting_major_1 ();
1816 * pin_queue now contains all candidate pointers, sorted and
1817 * uniqued. We must do two passes now to figure out which
1818 * objects are pinned.
1820 * The first is to find within the pin_queue the area for each
1821 * section. This requires that the pin_queue be sorted. We
1822 * also process the LOS objects and pinned chunks here.
1824 * The second, destructive, pass is to reduce the section
1825 * areas to pointers to the actually pinned objects.
1827 SGEN_LOG (6, "Pinning from sections");
1828 /* first pass for the sections */
1829 sgen_find_section_pin_queue_start_end (nursery_section);
1830 /* identify possible pointers to the insize of large objects */
1831 SGEN_LOG (6, "Pinning from large objects");
1832 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1834 if (sgen_find_optimized_pin_queue_area ((char*)bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1835 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
1837 if (sgen_los_object_is_pinned (bigobj->data)) {
1838 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1841 sgen_los_pin_object (bigobj->data);
1842 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1843 GRAY_OBJECT_ENQUEUE (gc_thread_gray_queue, bigobj->data, sgen_obj_get_descriptor ((GCObject*)bigobj->data));
1844 sgen_pin_stats_register_object (bigobj->data, GENERATION_OLD);
1845 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1846 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1847 (unsigned long)sgen_los_object_size (bigobj));
1849 sgen_client_pinned_los_object (bigobj->data);
1853 pin_objects_in_nursery (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT, ctx);
1854 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1855 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1857 major_collector.pin_objects (gc_thread_gray_queue);
1858 if (old_next_pin_slot)
1859 *old_next_pin_slot = sgen_get_pinned_count ();
1862 time_major_pinning += TV_ELAPSED (atv, btv);
1863 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (atv, btv));
1864 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1866 major_collector.init_to_space ();
1868 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1869 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1870 if (sgen_workers_have_idle_work ()) {
1872 * We force the finish of the worker with the new object ops context
1873 * which can also do copying. We need to have finished pinning.
1875 /* FIXME Implement parallel copying and get rid of this ineffective hack */
1876 if (major_collector.is_parallel)
1877 sgen_workers_start_all_workers (&major_collector.major_ops_conc_par_start, NULL);
1879 sgen_workers_start_all_workers (object_ops, NULL);
1881 sgen_workers_join ();
1885 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1886 main_gc_thread = mono_native_thread_self ();
1889 sgen_client_collecting_major_2 ();
1892 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1894 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1896 enqueue_scan_from_roots_jobs (gc_thread_gray_queue, heap_start, heap_end, object_ops, FALSE);
1899 time_major_scan_roots += TV_ELAPSED (atv, btv);
1902 * We start the concurrent worker after pinning and after we scanned the roots
1903 * in order to make sure that the worker does not finish before handling all
1906 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1907 gray_queue_redirect (gc_thread_gray_queue);
1908 if (precleaning_enabled) {
1909 sgen_workers_start_all_workers (object_ops, workers_finish_callback);
1911 sgen_workers_start_all_workers (object_ops, NULL);
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 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1922 sgen_workers_enqueue_job (&sj->job, FALSE);
1924 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ScanJob));
1925 sj->ops = object_ops;
1926 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1927 sgen_workers_enqueue_job (&sj->job, FALSE);
1930 time_major_scan_mod_union += TV_ELAPSED (btv, atv);
1933 sgen_pin_stats_report ();
1935 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1936 sgen_finish_pinning ();
1938 sgen_pin_stats_reset ();
1940 if (do_concurrent_checks)
1941 sgen_debug_check_nursery_is_clean ();
1946 major_start_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean concurrent, size_t *old_next_pin_slot)
1948 SgenObjectOperations *object_ops;
1950 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
1952 current_collection_generation = GENERATION_OLD;
1954 sgen_workers_assert_gray_queue_is_empty ();
1957 sgen_cement_reset ();
1960 g_assert (major_collector.is_concurrent);
1961 concurrent_collection_in_progress = TRUE;
1963 if (major_collector.is_parallel)
1964 object_ops = &major_collector.major_ops_conc_par_start;
1966 object_ops = &major_collector.major_ops_concurrent_start;
1969 object_ops = &major_collector.major_ops_serial;
1972 reset_pinned_from_failed_allocation ();
1974 sgen_memgov_major_collection_start (concurrent, reason);
1976 //count_ref_nonref_objs ();
1977 //consistency_check ();
1979 check_scan_starts ();
1982 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
1983 gc_stats.major_gc_count ++;
1985 if (major_collector.start_major_collection)
1986 major_collector.start_major_collection ();
1988 major_copy_or_mark_from_roots (gc_thread_gray_queue, old_next_pin_slot, concurrent ? COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT : COPY_OR_MARK_FROM_ROOTS_SERIAL, object_ops);
1992 major_finish_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean is_overflow, size_t old_next_pin_slot, gboolean forced)
1994 ScannedObjectCounts counts;
1995 SgenObjectOperations *object_ops;
1996 mword fragment_total;
2002 if (concurrent_collection_in_progress) {
2003 if (major_collector.is_parallel)
2004 object_ops = &major_collector.major_ops_conc_par_finish;
2006 object_ops = &major_collector.major_ops_concurrent_finish;
2008 major_copy_or_mark_from_roots (gc_thread_gray_queue, NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, object_ops);
2010 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2011 main_gc_thread = NULL;
2014 object_ops = &major_collector.major_ops_serial;
2017 sgen_workers_assert_gray_queue_is_empty ();
2019 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, gc_thread_gray_queue));
2021 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2023 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2025 if (objects_pinned) {
2026 g_assert (!concurrent_collection_in_progress);
2029 * This is slow, but we just OOM'd.
2031 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2032 * queue is laid out at this point.
2034 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2036 * We need to reestablish all pinned nursery objects in the pin queue
2037 * because they're needed for fragment creation. Unpinning happens by
2038 * walking the whole queue, so it's not necessary to reestablish where major
2039 * heap block pins are - all we care is that they're still in there
2042 sgen_optimize_pin_queue ();
2043 sgen_find_section_pin_queue_start_end (nursery_section);
2047 reset_heap_boundaries ();
2048 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2050 /* walk the pin_queue, build up the fragment list of free memory, unmark
2051 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2054 fragment_total = sgen_build_nursery_fragments (nursery_section, NULL);
2055 if (!fragment_total)
2057 SGEN_LOG (4, "Free space in nursery after major %ld", (long)fragment_total);
2059 if (do_concurrent_checks && concurrent_collection_in_progress)
2060 sgen_debug_check_nursery_is_clean ();
2062 /* prepare the pin queue for the next collection */
2063 sgen_finish_pinning ();
2065 /* Clear TLABs for all threads */
2066 sgen_clear_tlabs ();
2068 sgen_pin_stats_reset ();
2070 sgen_cement_clear_below_threshold ();
2072 if (check_mark_bits_after_major_collection)
2073 sgen_check_heap_marked (concurrent_collection_in_progress);
2076 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2078 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2079 sgen_memgov_major_pre_sweep ();
2082 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2087 time_major_los_sweep += TV_ELAPSED (atv, btv);
2089 major_collector.sweep ();
2091 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2094 time_major_sweep += TV_ELAPSED (btv, atv);
2096 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2098 if (sgen_have_pending_finalizers ()) {
2099 SGEN_LOG (4, "Finalizer-thread wakeup");
2100 sgen_client_finalize_notify ();
2103 sgen_memgov_major_collection_end (forced, concurrent_collection_in_progress, reason, is_overflow);
2104 current_collection_generation = -1;
2106 memset (&counts, 0, sizeof (ScannedObjectCounts));
2107 major_collector.finish_major_collection (&counts);
2109 sgen_workers_assert_gray_queue_is_empty ();
2111 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2112 if (concurrent_collection_in_progress)
2113 concurrent_collection_in_progress = FALSE;
2115 check_scan_starts ();
2117 binary_protocol_flush_buffers (FALSE);
2119 //consistency_check ();
2121 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2125 major_do_collection (const char *reason, gboolean is_overflow, gboolean forced)
2127 TV_DECLARE (time_start);
2128 TV_DECLARE (time_end);
2129 size_t old_next_pin_slot;
2130 SgenGrayQueue gc_thread_gray_queue;
2132 if (disable_major_collections)
2135 if (major_collector.get_and_reset_num_major_objects_marked) {
2136 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2137 g_assert (!num_marked);
2140 /* world must be stopped already */
2141 TV_GETTIME (time_start);
2143 init_gray_queue (&gc_thread_gray_queue, FALSE);
2144 major_start_collection (&gc_thread_gray_queue, reason, FALSE, &old_next_pin_slot);
2145 major_finish_collection (&gc_thread_gray_queue, reason, is_overflow, old_next_pin_slot, forced);
2146 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2148 TV_GETTIME (time_end);
2149 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2151 /* FIXME: also report this to the user, preferably in gc-end. */
2152 if (major_collector.get_and_reset_num_major_objects_marked)
2153 major_collector.get_and_reset_num_major_objects_marked ();
2155 return bytes_pinned_from_failed_allocation > 0;
2159 major_start_concurrent_collection (const char *reason)
2161 TV_DECLARE (time_start);
2162 TV_DECLARE (time_end);
2163 long long num_objects_marked;
2164 SgenGrayQueue gc_thread_gray_queue;
2166 if (disable_major_collections)
2169 TV_GETTIME (time_start);
2170 SGEN_TV_GETTIME (time_major_conc_collection_start);
2172 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2173 g_assert (num_objects_marked == 0);
2175 binary_protocol_concurrent_start ();
2177 init_gray_queue (&gc_thread_gray_queue, TRUE);
2178 // FIXME: store reason and pass it when finishing
2179 major_start_collection (&gc_thread_gray_queue, reason, TRUE, NULL);
2180 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2182 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2184 TV_GETTIME (time_end);
2185 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2187 current_collection_generation = -1;
2191 * Returns whether the major collection has finished.
2194 major_should_finish_concurrent_collection (void)
2196 return sgen_workers_all_done ();
2200 major_update_concurrent_collection (void)
2202 TV_DECLARE (total_start);
2203 TV_DECLARE (total_end);
2205 TV_GETTIME (total_start);
2207 binary_protocol_concurrent_update ();
2209 major_collector.update_cardtable_mod_union ();
2210 sgen_los_update_cardtable_mod_union ();
2212 TV_GETTIME (total_end);
2213 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2217 major_finish_concurrent_collection (gboolean forced)
2219 SgenGrayQueue gc_thread_gray_queue;
2220 TV_DECLARE (total_start);
2221 TV_DECLARE (total_end);
2223 TV_GETTIME (total_start);
2225 binary_protocol_concurrent_finish ();
2228 * We need to stop all workers since we're updating the cardtable below.
2229 * The workers will be resumed with a finishing pause context to avoid
2230 * additional cardtable and object scanning.
2232 sgen_workers_stop_all_workers ();
2234 SGEN_TV_GETTIME (time_major_conc_collection_end);
2235 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2237 major_collector.update_cardtable_mod_union ();
2238 sgen_los_update_cardtable_mod_union ();
2240 if (mod_union_consistency_check)
2241 sgen_check_mod_union_consistency ();
2243 current_collection_generation = GENERATION_OLD;
2244 sgen_cement_reset ();
2245 init_gray_queue (&gc_thread_gray_queue, FALSE);
2246 major_finish_collection (&gc_thread_gray_queue, "finishing", FALSE, -1, forced);
2247 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2249 TV_GETTIME (total_end);
2250 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2252 current_collection_generation = -1;
2256 * Ensure an allocation request for @size will succeed by freeing enough memory.
2258 * LOCKING: The GC lock MUST be held.
2261 sgen_ensure_free_space (size_t size, int generation)
2263 int generation_to_collect = -1;
2264 const char *reason = NULL;
2266 if (generation == GENERATION_OLD) {
2267 if (sgen_need_major_collection (size)) {
2268 reason = "LOS overflow";
2269 generation_to_collect = GENERATION_OLD;
2272 if (degraded_mode) {
2273 if (sgen_need_major_collection (size)) {
2274 reason = "Degraded mode overflow";
2275 generation_to_collect = GENERATION_OLD;
2277 } else if (sgen_need_major_collection (size)) {
2278 reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
2279 generation_to_collect = GENERATION_OLD;
2281 generation_to_collect = GENERATION_NURSERY;
2282 reason = "Nursery full";
2286 if (generation_to_collect == -1) {
2287 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2288 generation_to_collect = GENERATION_OLD;
2289 reason = "Finish concurrent collection";
2293 if (generation_to_collect == -1)
2295 sgen_perform_collection (size, generation_to_collect, reason, FALSE, TRUE);
2299 * LOCKING: Assumes the GC lock is held.
2302 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw)
2304 TV_DECLARE (gc_total_start);
2305 TV_DECLARE (gc_total_end);
2306 int overflow_generation_to_collect = -1;
2307 int oldest_generation_collected = generation_to_collect;
2308 const char *overflow_reason = NULL;
2309 gboolean finish_concurrent = concurrent_collection_in_progress && (major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD);
2311 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2313 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2316 sgen_stop_world (generation_to_collect);
2318 SGEN_ASSERT (0, sgen_is_world_stopped (), "We can only collect if the world is stopped");
2321 TV_GETTIME (gc_total_start);
2323 // FIXME: extract overflow reason
2324 // FIXME: minor overflow for concurrent case
2325 if (generation_to_collect == GENERATION_NURSERY && !finish_concurrent) {
2326 if (concurrent_collection_in_progress)
2327 major_update_concurrent_collection ();
2329 if (collect_nursery (reason, FALSE, NULL) && !concurrent_collection_in_progress) {
2330 overflow_generation_to_collect = GENERATION_OLD;
2331 overflow_reason = "Minor overflow";
2333 } else if (finish_concurrent) {
2334 major_finish_concurrent_collection (wait_to_finish);
2335 oldest_generation_collected = GENERATION_OLD;
2337 SGEN_ASSERT (0, generation_to_collect == GENERATION_OLD, "We should have handled nursery collections above");
2338 if (major_collector.is_concurrent && !wait_to_finish) {
2339 collect_nursery ("Concurrent start", FALSE, NULL);
2340 major_start_concurrent_collection (reason);
2341 oldest_generation_collected = GENERATION_NURSERY;
2342 } else if (major_do_collection (reason, FALSE, wait_to_finish)) {
2343 overflow_generation_to_collect = GENERATION_NURSERY;
2344 overflow_reason = "Excessive pinning";
2348 if (overflow_generation_to_collect != -1) {
2349 SGEN_ASSERT (0, !concurrent_collection_in_progress, "We don't yet support overflow collections with the concurrent collector");
2352 * We need to do an overflow collection, either because we ran out of memory
2353 * or the nursery is fully pinned.
2356 if (overflow_generation_to_collect == GENERATION_NURSERY)
2357 collect_nursery (overflow_reason, TRUE, NULL);
2359 major_do_collection (overflow_reason, TRUE, wait_to_finish);
2361 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2364 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2366 /* this also sets the proper pointers for the next allocation */
2367 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2368 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2369 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2370 sgen_dump_pin_queue ();
2374 TV_GETTIME (gc_total_end);
2375 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2378 sgen_restart_world (oldest_generation_collected);
2382 * ######################################################################
2383 * ######## Memory allocation from the OS
2384 * ######################################################################
2385 * This section of code deals with getting memory from the OS and
2386 * allocating memory for GC-internal data structures.
2387 * Internal memory can be handled with a freelist for small objects.
2393 G_GNUC_UNUSED static void
2394 report_internal_mem_usage (void)
2396 printf ("Internal memory usage:\n");
2397 sgen_report_internal_mem_usage ();
2398 printf ("Pinned memory usage:\n");
2399 major_collector.report_pinned_memory_usage ();
2403 * ######################################################################
2404 * ######## Finalization support
2405 * ######################################################################
2409 * If the object has been forwarded it means it's still referenced from a root.
2410 * If it is pinned it's still alive as well.
2411 * A LOS object is only alive if we have pinned it.
2412 * Return TRUE if @obj is ready to be finalized.
2414 static inline gboolean
2415 sgen_is_object_alive (GCObject *object)
2417 if (ptr_in_nursery (object))
2418 return sgen_nursery_is_object_alive (object);
2420 return sgen_major_is_object_alive (object);
2424 * This function returns true if @object is either alive and belongs to the
2425 * current collection - major collections are full heap, so old gen objects
2426 * are never alive during a minor collection.
2429 sgen_is_object_alive_and_on_current_collection (GCObject *object)
2431 if (ptr_in_nursery (object))
2432 return sgen_nursery_is_object_alive (object);
2434 if (current_collection_generation == GENERATION_NURSERY)
2437 return sgen_major_is_object_alive (object);
2442 sgen_gc_is_object_ready_for_finalization (GCObject *object)
2444 return !sgen_is_object_alive (object);
2448 sgen_queue_finalization_entry (GCObject *obj)
2450 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2452 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2454 sgen_client_object_queued_for_finalization (obj);
2458 sgen_object_is_live (GCObject *obj)
2460 return sgen_is_object_alive_and_on_current_collection (obj);
2464 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2465 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2466 * all finalizers have really finished running.
2468 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2469 * This means that just checking whether the queues are empty leaves the possibility that an
2470 * object might have been dequeued but not yet finalized. That's why we need the additional
2471 * flag `pending_unqueued_finalizer`.
2474 static volatile gboolean pending_unqueued_finalizer = FALSE;
2475 volatile gboolean sgen_suspend_finalizers = FALSE;
2478 sgen_set_suspend_finalizers (void)
2480 sgen_suspend_finalizers = TRUE;
2484 sgen_gc_invoke_finalizers (void)
2488 g_assert (!pending_unqueued_finalizer);
2490 /* FIXME: batch to reduce lock contention */
2491 while (sgen_have_pending_finalizers ()) {
2497 * We need to set `pending_unqueued_finalizer` before dequeing the
2498 * finalizable object.
2500 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2501 pending_unqueued_finalizer = TRUE;
2502 mono_memory_write_barrier ();
2503 obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
2504 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2505 pending_unqueued_finalizer = TRUE;
2506 mono_memory_write_barrier ();
2507 obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
2513 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2521 /* the object is on the stack so it is pinned */
2522 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2523 sgen_client_run_finalize (obj);
2526 if (pending_unqueued_finalizer) {
2527 mono_memory_write_barrier ();
2528 pending_unqueued_finalizer = FALSE;
2535 sgen_have_pending_finalizers (void)
2537 if (sgen_suspend_finalizers)
2539 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2543 * ######################################################################
2544 * ######## registered roots support
2545 * ######################################################################
2549 * We do not coalesce roots.
2552 sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg)
2554 RootRecord new_root;
2557 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2558 RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
2559 /* we allow changing the size and the descriptor (for thread statics etc) */
2561 size_t old_size = root->end_root - start;
2562 root->end_root = start + size;
2563 SGEN_ASSERT (0, !!root->root_desc == !!descr, "Can't change whether a root is precise or conservative.");
2564 SGEN_ASSERT (0, root->source == source, "Can't change a root's source identifier.");
2565 SGEN_ASSERT (0, !!root->msg == !!msg, "Can't change a root's message.");
2566 root->root_desc = descr;
2568 roots_size -= old_size;
2574 new_root.end_root = start + size;
2575 new_root.root_desc = descr;
2576 new_root.source = source;
2579 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2582 SGEN_LOG (3, "Added root for range: %p-%p, descr: %llx (%d/%d bytes)", start, new_root.end_root, (long long)descr, (int)size, (int)roots_size);
2589 sgen_deregister_root (char* addr)
2595 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2596 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2597 roots_size -= (root.end_root - addr);
2603 * ######################################################################
2604 * ######## Thread handling (stop/start code)
2605 * ######################################################################
2609 sgen_get_current_collection_generation (void)
2611 return current_collection_generation;
2615 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2617 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2619 sgen_client_thread_register (info, stack_bottom_fallback);
2625 sgen_thread_unregister (SgenThreadInfo *p)
2627 sgen_client_thread_unregister (p);
2631 * ######################################################################
2632 * ######## Write barriers
2633 * ######################################################################
2637 * Note: the write barriers first do the needed GC work and then do the actual store:
2638 * this way the value is visible to the conservative GC scan after the write barrier
2639 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2640 * the conservative scan, otherwise by the remembered set scan.
2644 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2646 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2647 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2648 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2649 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2653 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2654 if (binary_protocol_is_heavy_enabled ()) {
2656 for (i = 0; i < count; ++i) {
2657 gpointer dest = (gpointer*)dest_ptr + i;
2658 gpointer obj = *((gpointer*)src_ptr + i);
2660 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2665 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2669 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2673 HEAVY_STAT (++stat_wbarrier_generic_store);
2675 sgen_client_wbarrier_generic_nostore_check (ptr);
2677 obj = *(gpointer*)ptr;
2679 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2682 * We need to record old->old pointer locations for the
2683 * concurrent collector.
2685 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2686 SGEN_LOG (8, "Skipping remset at %p", ptr);
2690 SGEN_LOG (8, "Adding remset at %p", ptr);
2692 remset.wbarrier_generic_nostore (ptr);
2696 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2698 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2699 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2700 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2701 mono_gc_wbarrier_generic_nostore (ptr);
2702 sgen_dummy_use (value);
2705 /* Same as mono_gc_wbarrier_generic_store () but performs the store
2706 * as an atomic operation with release semantics.
2709 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2711 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2713 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2715 InterlockedWritePointer ((volatile gpointer *)ptr, value);
2717 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2718 mono_gc_wbarrier_generic_nostore (ptr);
2720 sgen_dummy_use (value);
2724 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
2726 GCObject **dest = (GCObject **)_dest;
2727 GCObject **src = (GCObject **)_src;
2731 mono_gc_wbarrier_generic_store (dest, *src);
2736 size -= SIZEOF_VOID_P;
2742 * ######################################################################
2743 * ######## Other mono public interface functions.
2744 * ######################################################################
2748 sgen_gc_collect (int generation)
2753 sgen_perform_collection (0, generation, "user request", TRUE, TRUE);
2758 sgen_gc_collection_count (int generation)
2760 if (generation == 0)
2761 return gc_stats.minor_gc_count;
2762 return gc_stats.major_gc_count;
2766 sgen_gc_get_used_size (void)
2770 tot = los_memory_usage;
2771 tot += nursery_section->next_data - nursery_section->data;
2772 tot += major_collector.get_used_size ();
2773 /* FIXME: account for pinned objects */
2779 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2783 va_start (ap, description_format);
2785 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2786 vfprintf (stderr, description_format, ap);
2788 fprintf (stderr, " - %s", fallback);
2789 fprintf (stderr, "\n");
2795 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2798 double val = strtod (opt, &endptr);
2799 if (endptr == opt) {
2800 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2803 else if (val < min || val > max) {
2804 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
2816 char *major_collector_opt = NULL;
2817 char *minor_collector_opt = NULL;
2818 char *params_opts = NULL;
2819 char *debug_opts = NULL;
2820 size_t max_heap = 0;
2821 size_t soft_limit = 0;
2823 gboolean debug_print_allowance = FALSE;
2824 double allowance_ratio = 0, save_target = 0;
2825 gboolean cement_enabled = TRUE;
2828 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
2831 /* already inited */
2834 /* being inited by another thread */
2835 mono_thread_info_usleep (1000);
2838 /* we will init it */
2841 g_assert_not_reached ();
2843 } while (result != 0);
2845 SGEN_TV_GETTIME (sgen_init_timestamp);
2847 #ifdef SGEN_WITHOUT_MONO
2848 mono_thread_smr_init ();
2851 mono_coop_mutex_init (&gc_mutex);
2853 gc_debug_file = stderr;
2855 mono_coop_mutex_init (&sgen_interruption_mutex);
2857 if ((env = g_getenv (MONO_GC_PARAMS_NAME)) || gc_params_options) {
2858 params_opts = g_strdup_printf ("%s,%s", gc_params_options ? gc_params_options : "", env ? env : "");
2862 opts = g_strsplit (params_opts, ",", -1);
2863 for (ptr = opts; *ptr; ++ptr) {
2865 if (g_str_has_prefix (opt, "major=")) {
2866 opt = strchr (opt, '=') + 1;
2867 major_collector_opt = g_strdup (opt);
2868 } else if (g_str_has_prefix (opt, "minor=")) {
2869 opt = strchr (opt, '=') + 1;
2870 minor_collector_opt = g_strdup (opt);
2878 sgen_init_internal_allocator ();
2879 sgen_init_nursery_allocator ();
2880 sgen_init_fin_weak_hash ();
2881 sgen_init_hash_table ();
2882 sgen_init_descriptors ();
2883 sgen_init_gray_queues ();
2884 sgen_init_allocator ();
2885 sgen_init_gchandles ();
2887 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
2888 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
2890 sgen_client_init ();
2892 if (!minor_collector_opt) {
2893 sgen_simple_nursery_init (&sgen_minor_collector);
2895 if (!strcmp (minor_collector_opt, "simple")) {
2897 sgen_simple_nursery_init (&sgen_minor_collector);
2898 } else if (!strcmp (minor_collector_opt, "split")) {
2899 sgen_split_nursery_init (&sgen_minor_collector);
2901 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
2902 goto use_simple_nursery;
2906 if (!major_collector_opt) {
2908 DEFAULT_MAJOR_INIT (&major_collector);
2909 } else if (!strcmp (major_collector_opt, "marksweep")) {
2910 sgen_marksweep_init (&major_collector);
2911 } else if (!strcmp (major_collector_opt, "marksweep-conc")) {
2912 sgen_marksweep_conc_init (&major_collector);
2913 } else if (!strcmp (major_collector_opt, "marksweep-conc-par")) {
2914 sgen_marksweep_conc_par_init (&major_collector);
2916 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `" DEFAULT_MAJOR_NAME "` instead.", "Unknown major collector `%s'.", major_collector_opt);
2917 goto use_default_major;
2920 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
2923 gboolean usage_printed = FALSE;
2925 for (ptr = opts; *ptr; ++ptr) {
2927 if (!strcmp (opt, ""))
2929 if (g_str_has_prefix (opt, "major="))
2931 if (g_str_has_prefix (opt, "minor="))
2933 if (g_str_has_prefix (opt, "max-heap-size=")) {
2934 size_t page_size = mono_pagesize ();
2935 size_t max_heap_candidate = 0;
2936 opt = strchr (opt, '=') + 1;
2937 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
2938 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
2939 if (max_heap != max_heap_candidate)
2940 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
2942 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
2946 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
2947 opt = strchr (opt, '=') + 1;
2948 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
2949 if (soft_limit <= 0) {
2950 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
2954 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
2960 if (g_str_has_prefix (opt, "nursery-size=")) {
2962 opt = strchr (opt, '=') + 1;
2963 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
2964 if ((val & (val - 1))) {
2965 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
2969 if (val < SGEN_MAX_NURSERY_WASTE) {
2970 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
2971 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
2975 sgen_nursery_size = val;
2976 sgen_nursery_bits = 0;
2977 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
2980 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
2986 if (g_str_has_prefix (opt, "save-target-ratio=")) {
2988 opt = strchr (opt, '=') + 1;
2989 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
2990 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
2995 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
2997 opt = strchr (opt, '=') + 1;
2998 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
2999 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3000 allowance_ratio = val;
3005 if (!strcmp (opt, "cementing")) {
3006 cement_enabled = TRUE;
3009 if (!strcmp (opt, "no-cementing")) {
3010 cement_enabled = FALSE;
3014 if (!strcmp (opt, "precleaning")) {
3015 precleaning_enabled = TRUE;
3018 if (!strcmp (opt, "no-precleaning")) {
3019 precleaning_enabled = FALSE;
3023 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3026 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3029 if (sgen_client_handle_gc_param (opt))
3032 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3037 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3038 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3039 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3040 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3041 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3042 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3043 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3044 fprintf (stderr, " [no-]cementing\n");
3045 if (major_collector.print_gc_param_usage)
3046 major_collector.print_gc_param_usage ();
3047 if (sgen_minor_collector.print_gc_param_usage)
3048 sgen_minor_collector.print_gc_param_usage ();
3049 sgen_client_print_gc_params_usage ();
3050 fprintf (stderr, " Experimental options:\n");
3051 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3052 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);
3053 fprintf (stderr, "\n");
3055 usage_printed = TRUE;
3060 if (major_collector_opt)
3061 g_free (major_collector_opt);
3063 if (minor_collector_opt)
3064 g_free (minor_collector_opt);
3067 g_free (params_opts);
3071 sgen_pinning_init ();
3072 sgen_cement_init (cement_enabled);
3074 if ((env = g_getenv (MONO_GC_DEBUG_NAME)) || gc_debug_options) {
3075 debug_opts = g_strdup_printf ("%s,%s", gc_debug_options ? gc_debug_options : "", env ? env : "");
3079 gboolean usage_printed = FALSE;
3081 opts = g_strsplit (debug_opts, ",", -1);
3082 for (ptr = opts; ptr && *ptr; ptr ++) {
3084 if (!strcmp (opt, ""))
3086 if (opt [0] >= '0' && opt [0] <= '9') {
3087 gc_debug_level = atoi (opt);
3092 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3093 gc_debug_file = fopen (rf, "wb");
3095 gc_debug_file = stderr;
3098 } else if (!strcmp (opt, "print-allowance")) {
3099 debug_print_allowance = TRUE;
3100 } else if (!strcmp (opt, "print-pinning")) {
3101 sgen_pin_stats_enable ();
3102 } else if (!strcmp (opt, "verify-before-allocs")) {
3103 verify_before_allocs = 1;
3104 has_per_allocation_action = TRUE;
3105 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3106 char *arg = strchr (opt, '=') + 1;
3107 verify_before_allocs = atoi (arg);
3108 has_per_allocation_action = TRUE;
3109 } else if (!strcmp (opt, "collect-before-allocs")) {
3110 collect_before_allocs = 1;
3111 has_per_allocation_action = TRUE;
3112 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3113 char *arg = strchr (opt, '=') + 1;
3114 has_per_allocation_action = TRUE;
3115 collect_before_allocs = atoi (arg);
3116 } else if (!strcmp (opt, "verify-before-collections")) {
3117 whole_heap_check_before_collection = TRUE;
3118 } else if (!strcmp (opt, "check-remset-consistency")) {
3119 remset_consistency_checks = TRUE;
3120 nursery_clear_policy = CLEAR_AT_GC;
3121 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3122 if (!major_collector.is_concurrent) {
3123 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3126 mod_union_consistency_check = TRUE;
3127 } else if (!strcmp (opt, "check-mark-bits")) {
3128 check_mark_bits_after_major_collection = TRUE;
3129 } else if (!strcmp (opt, "check-nursery-pinned")) {
3130 check_nursery_objects_pinned = TRUE;
3131 } else if (!strcmp (opt, "clear-at-gc")) {
3132 nursery_clear_policy = CLEAR_AT_GC;
3133 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3134 nursery_clear_policy = CLEAR_AT_GC;
3135 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3136 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3137 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3138 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3139 } else if (!strcmp (opt, "check-scan-starts")) {
3140 do_scan_starts_check = TRUE;
3141 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3142 do_verify_nursery = TRUE;
3143 } else if (!strcmp (opt, "check-concurrent")) {
3144 if (!major_collector.is_concurrent) {
3145 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3148 nursery_clear_policy = CLEAR_AT_GC;
3149 do_concurrent_checks = TRUE;
3150 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3151 do_dump_nursery_content = TRUE;
3152 } else if (!strcmp (opt, "disable-minor")) {
3153 disable_minor_collections = TRUE;
3154 } else if (!strcmp (opt, "disable-major")) {
3155 disable_major_collections = TRUE;
3156 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3157 char *filename = strchr (opt, '=') + 1;
3158 nursery_clear_policy = CLEAR_AT_GC;
3159 sgen_debug_enable_heap_dump (filename);
3160 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3161 char *filename = strchr (opt, '=') + 1;
3162 char *colon = strrchr (filename, ':');
3165 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3166 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3171 binary_protocol_init (filename, (long long)limit);
3172 } else if (!strcmp (opt, "nursery-canaries")) {
3173 do_verify_nursery = TRUE;
3174 enable_nursery_canaries = TRUE;
3175 } else if (!sgen_client_handle_gc_debug (opt)) {
3176 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3181 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);
3182 fprintf (stderr, "Valid <option>s are:\n");
3183 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3184 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3185 fprintf (stderr, " check-remset-consistency\n");
3186 fprintf (stderr, " check-mark-bits\n");
3187 fprintf (stderr, " check-nursery-pinned\n");
3188 fprintf (stderr, " verify-before-collections\n");
3189 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3190 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3191 fprintf (stderr, " disable-minor\n");
3192 fprintf (stderr, " disable-major\n");
3193 fprintf (stderr, " check-concurrent\n");
3194 fprintf (stderr, " clear-[nursery-]at-gc\n");
3195 fprintf (stderr, " clear-at-tlab-creation\n");
3196 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3197 fprintf (stderr, " check-scan-starts\n");
3198 fprintf (stderr, " print-allowance\n");
3199 fprintf (stderr, " print-pinning\n");
3200 fprintf (stderr, " heap-dump=<filename>\n");
3201 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3202 fprintf (stderr, " nursery-canaries\n");
3203 sgen_client_print_gc_debug_usage ();
3204 fprintf (stderr, "\n");
3206 usage_printed = TRUE;
3213 g_free (debug_opts);
3215 if (check_mark_bits_after_major_collection)
3216 nursery_clear_policy = CLEAR_AT_GC;
3218 if (major_collector.post_param_init)
3219 major_collector.post_param_init (&major_collector);
3221 if (major_collector.needs_thread_pool) {
3222 int num_workers = 1;
3223 if (major_collector.is_parallel) {
3224 /* FIXME Detect the number of physical cores, instead of logical */
3225 num_workers = mono_cpu_count () / 2;
3226 if (num_workers < 1)
3229 sgen_workers_init (num_workers, (SgenWorkerCallback) major_collector.worker_init_cb);
3232 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3234 memset (&remset, 0, sizeof (remset));
3236 sgen_card_table_init (&remset);
3238 sgen_register_root (NULL, 0, sgen_make_user_root_descriptor (sgen_mark_normal_gc_handles), ROOT_TYPE_NORMAL, MONO_ROOT_SOURCE_GC_HANDLE, "normal gc handles");
3242 sgen_init_bridge ();
3246 sgen_gc_initialized ()
3248 return gc_initialized > 0;
3252 sgen_get_nursery_clear_policy (void)
3254 return nursery_clear_policy;
3260 mono_coop_mutex_lock (&gc_mutex);
3264 sgen_gc_unlock (void)
3266 mono_coop_mutex_unlock (&gc_mutex);
3270 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3272 major_collector.iterate_live_block_ranges (callback);
3276 sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback)
3278 major_collector.iterate_block_ranges (callback);
3282 sgen_get_major_collector (void)
3284 return &major_collector;
3288 sgen_get_remset (void)
3294 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3296 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3297 sgen_los_count_cards (los_total, los_marked);
3300 static gboolean world_is_stopped = FALSE;
3302 /* LOCKING: assumes the GC lock is held */
3304 sgen_stop_world (int generation)
3306 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3308 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3310 binary_protocol_world_stopping (generation, sgen_timestamp (), (gpointer) (gsize) mono_native_thread_id_get ());
3312 sgen_client_stop_world (generation);
3314 world_is_stopped = TRUE;
3316 if (binary_protocol_is_heavy_enabled ())
3317 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3318 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3321 /* LOCKING: assumes the GC lock is held */
3323 sgen_restart_world (int generation)
3325 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3328 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3330 if (binary_protocol_is_heavy_enabled ())
3331 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3332 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3334 world_is_stopped = FALSE;
3336 sgen_client_restart_world (generation, &stw_time);
3338 binary_protocol_world_restarted (generation, sgen_timestamp ());
3340 if (sgen_client_bridge_need_processing ())
3341 sgen_client_bridge_processing_finish (generation);
3343 sgen_memgov_collection_end (generation, stw_time);
3347 sgen_is_world_stopped (void)
3349 return world_is_stopped;
3353 sgen_check_whole_heap_stw (void)
3355 sgen_stop_world (0);
3356 sgen_clear_nursery_fragments ();
3357 sgen_check_whole_heap (TRUE);
3358 sgen_restart_world (0);
3362 sgen_timestamp (void)
3364 SGEN_TV_DECLARE (timestamp);
3365 SGEN_TV_GETTIME (timestamp);
3366 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3369 #endif /* HAVE_SGEN_GC */