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_enable_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_gray_queue_set_alloc_prepare (queue, sgen_workers_take_from_queue_and_awake);
432 sgen_workers_take_from_queue_and_awake (queue);
436 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries)
438 while (start < end) {
442 if (!*(void**)start) {
443 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
448 if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
454 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
455 CHECK_CANARY_FOR_OBJECT ((GCObject*)obj, fail_on_canaries);
456 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
457 callback ((GCObject*)obj, size, data);
458 CANARIFY_SIZE (size);
460 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
468 * sgen_add_to_global_remset:
470 * The global remset contains locations which point into newspace after
471 * a minor collection. This can happen if the objects they point to are pinned.
473 * LOCKING: If called from a parallel collector, the global remset
474 * lock must be held. For serial collectors that is not necessary.
477 sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
479 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
481 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
483 if (!major_collector.is_concurrent) {
484 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
486 if (current_collection_generation == -1)
487 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
490 if (!object_is_pinned (obj))
491 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");
492 else if (sgen_cement_lookup_or_register (obj))
495 remset.record_pointer (ptr);
497 sgen_pin_stats_register_global_remset (obj);
499 SGEN_LOG (8, "Adding global remset for %p", ptr);
500 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
504 * sgen_drain_gray_stack:
506 * Scan objects in the gray stack until the stack is empty. This should be called
507 * frequently after each object is copied, to achieve better locality and cache
512 sgen_drain_gray_stack (ScanCopyContext ctx)
514 ScanObjectFunc scan_func = ctx.ops->scan_object;
515 SgenGrayQueue *queue = ctx.queue;
517 if (ctx.ops->drain_gray_stack)
518 return ctx.ops->drain_gray_stack (queue);
523 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
526 SGEN_LOG (9, "Precise gray object scan %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
527 scan_func (obj, desc, queue);
533 * Addresses in the pin queue are already sorted. This function finds
534 * the object header for each address and pins the object. The
535 * addresses must be inside the nursery section. The (start of the)
536 * address array is overwritten with the addresses of the actually
537 * pinned objects. Return the number of pinned objects.
540 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
542 GCMemSection *section = nursery_section;
543 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
544 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
545 void *start_nursery = section->data;
546 void *end_nursery = section->next_data;
551 void *pinning_front = start_nursery;
553 void **definitely_pinned = start;
554 ScanObjectFunc scan_func = ctx.ops->scan_object;
555 SgenGrayQueue *queue = ctx.queue;
557 sgen_nursery_allocator_prepare_for_pinning ();
559 while (start < end) {
560 GCObject *obj_to_pin = NULL;
561 size_t obj_to_pin_size = 0;
566 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
567 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
574 SGEN_LOG (5, "Considering pinning addr %p", addr);
575 /* We've already processed everything up to pinning_front. */
576 if (addr < pinning_front) {
582 * Find the closest scan start <= addr. We might search backward in the
583 * scan_starts array because entries might be NULL. In the worst case we
584 * start at start_nursery.
586 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
587 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
588 search_start = (void*)section->scan_starts [idx];
589 if (!search_start || search_start > addr) {
592 search_start = section->scan_starts [idx];
593 if (search_start && search_start <= addr)
596 if (!search_start || search_start > addr)
597 search_start = start_nursery;
601 * If the pinning front is closer than the scan start we found, start
602 * searching at the front.
604 if (search_start < pinning_front)
605 search_start = pinning_front;
608 * Now addr should be in an object a short distance from search_start.
610 * search_start must point to zeroed mem or point to an object.
613 size_t obj_size, canarified_obj_size;
616 if (!*(void**)search_start) {
617 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
618 /* The loop condition makes sure we don't overrun addr. */
622 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
625 * Filler arrays are marked by an invalid sync word. We don't
626 * consider them for pinning. They are not delimited by canaries,
629 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
630 CHECK_CANARY_FOR_OBJECT (search_start, TRUE);
631 CANARIFY_SIZE (canarified_obj_size);
633 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
634 /* This is the object we're looking for. */
635 obj_to_pin = (GCObject*)search_start;
636 obj_to_pin_size = canarified_obj_size;
641 /* Skip to the next object */
642 search_start = (void*)((char*)search_start + canarified_obj_size);
643 } while (search_start <= addr);
645 /* We've searched past the address we were looking for. */
647 pinning_front = search_start;
648 goto next_pin_queue_entry;
652 * We've found an object to pin. It might still be a dummy array, but we
653 * can advance the pinning front in any case.
655 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
658 * If this is a dummy array marking the beginning of a nursery
659 * fragment, we don't pin it.
661 if (sgen_client_object_is_array_fill (obj_to_pin))
662 goto next_pin_queue_entry;
665 * Finally - pin the object!
667 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
668 if (do_scan_objects) {
669 scan_func (obj_to_pin, desc, queue);
671 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
672 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
673 binary_protocol_pin (obj_to_pin,
674 (gpointer)LOAD_VTABLE (obj_to_pin),
675 safe_object_get_size (obj_to_pin));
677 pin_object (obj_to_pin);
678 GRAY_OBJECT_ENQUEUE (queue, obj_to_pin, desc);
679 sgen_pin_stats_register_object (obj_to_pin, GENERATION_NURSERY);
680 definitely_pinned [count] = obj_to_pin;
683 if (concurrent_collection_in_progress)
684 sgen_pinning_register_pinned_in_nursery (obj_to_pin);
686 next_pin_queue_entry:
690 sgen_client_nursery_objects_pinned (definitely_pinned, count);
691 stat_pinned_objects += count;
696 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
700 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
703 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
704 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
708 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
709 * when we can't promote an object because we're out of memory.
712 sgen_pin_object (GCObject *object, SgenGrayQueue *queue)
714 SGEN_ASSERT (0, sgen_ptr_in_nursery (object), "We're only supposed to use this for pinning nursery objects when out of memory.");
717 * All pinned objects are assumed to have been staged, so we need to stage as well.
718 * Also, the count of staged objects shows that "late pinning" happened.
720 sgen_pin_stage_ptr (object);
722 SGEN_PIN_OBJECT (object);
723 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
726 sgen_pin_stats_register_object (object, GENERATION_NURSERY);
728 GRAY_OBJECT_ENQUEUE (queue, object, sgen_obj_get_descriptor_safe (object));
731 /* Sort the addresses in array in increasing order.
732 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
735 sgen_sort_addresses (void **array, size_t size)
740 for (i = 1; i < size; ++i) {
743 size_t parent = (child - 1) / 2;
745 if (array [parent] >= array [child])
748 tmp = array [parent];
749 array [parent] = array [child];
756 for (i = size - 1; i > 0; --i) {
759 array [i] = array [0];
765 while (root * 2 + 1 <= end) {
766 size_t child = root * 2 + 1;
768 if (child < end && array [child] < array [child + 1])
770 if (array [root] >= array [child])
774 array [root] = array [child];
783 * Scan the memory between start and end and queue values which could be pointers
784 * to the area between start_nursery and end_nursery for later consideration.
785 * Typically used for thread stacks.
788 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
792 SGEN_ASSERT (0, ((mword)start & (SIZEOF_VOID_P - 1)) == 0, "Why are we scanning for references in unaligned memory ?");
794 #if defined(VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE) && !defined(_WIN64)
795 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
798 while (start < end) {
800 * *start can point to the middle of an object
801 * note: should we handle pointing at the end of an object?
802 * pinning in C# code disallows pointing at the end of an object
803 * but there is some small chance that an optimizing C compiler
804 * may keep the only reference to an object by pointing
805 * at the end of it. We ignore this small chance for now.
806 * Pointers to the end of an object are indistinguishable
807 * from pointers to the start of the next object in memory
808 * so if we allow that we'd need to pin two objects...
809 * We queue the pointer in an array, the
810 * array will then be sorted and uniqued. This way
811 * we can coalesce several pinning pointers and it should
812 * be faster since we'd do a memory scan with increasing
813 * addresses. Note: we can align the address to the allocation
814 * alignment, so the unique process is more effective.
816 mword addr = (mword)*start;
817 addr &= ~(ALLOC_ALIGN - 1);
818 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
819 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
820 sgen_pin_stage_ptr ((void*)addr);
821 binary_protocol_pin_stage (start, (void*)addr);
822 sgen_pin_stats_register_address ((char*)addr, pin_type);
828 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
832 * The first thing we do in a collection is to identify pinned objects.
833 * This function considers all the areas of memory that need to be
834 * conservatively scanned.
837 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
841 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);
842 /* objects pinned from the API are inside these roots */
843 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
844 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
845 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
846 } SGEN_HASH_TABLE_FOREACH_END;
847 /* now deal with the thread stacks
848 * in the future we should be able to conservatively scan only:
849 * *) the cpu registers
850 * *) the unmanaged stack frames
851 * *) the _last_ managed stack frame
852 * *) pointers slots in managed frames
854 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
858 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
860 ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
861 ctx->ops->copy_or_mark_object (obj, ctx->queue);
865 * The memory area from start_root to end_root contains pointers to objects.
866 * Their position is precisely described by @desc (this means that the pointer
867 * can be either NULL or the pointer to the start of an object).
868 * This functions copies them to to_space updates them.
870 * This function is not thread-safe!
873 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, SgenDescriptor desc, ScanCopyContext ctx)
875 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
876 SgenGrayQueue *queue = ctx.queue;
878 switch (desc & ROOT_DESC_TYPE_MASK) {
879 case ROOT_DESC_BITMAP:
880 desc >>= ROOT_DESC_TYPE_SHIFT;
882 if ((desc & 1) && *start_root) {
883 copy_func ((GCObject**)start_root, queue);
884 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
890 case ROOT_DESC_COMPLEX: {
891 gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
892 gsize bwords = (*bitmap_data) - 1;
893 void **start_run = start_root;
895 while (bwords-- > 0) {
896 gsize bmap = *bitmap_data++;
897 void **objptr = start_run;
899 if ((bmap & 1) && *objptr) {
900 copy_func ((GCObject**)objptr, queue);
901 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
906 start_run += GC_BITS_PER_WORD;
910 case ROOT_DESC_USER: {
911 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
912 marker (start_root, single_arg_user_copy_or_mark, &ctx);
915 case ROOT_DESC_RUN_LEN:
916 g_assert_not_reached ();
918 g_assert_not_reached ();
923 reset_heap_boundaries (void)
925 lowest_heap_address = ~(mword)0;
926 highest_heap_address = 0;
930 sgen_update_heap_boundaries (mword low, mword high)
935 old = lowest_heap_address;
938 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
941 old = highest_heap_address;
944 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
948 * Allocate and setup the data structures needed to be able to allocate objects
949 * in the nursery. The nursery is stored in nursery_section.
954 GCMemSection *section;
961 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
962 /* later we will alloc a larger area for the nursery but only activate
963 * what we need. The rest will be used as expansion if we have too many pinned
964 * objects in the existing nursery.
966 /* FIXME: handle OOM */
967 section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
969 alloc_size = sgen_nursery_size;
971 /* If there isn't enough space even for the nursery we should simply abort. */
972 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
974 data = (char *)major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
975 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
976 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 ());
977 section->data = section->next_data = data;
978 section->size = alloc_size;
979 section->end_data = data + sgen_nursery_size;
980 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
981 section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
982 section->num_scan_start = scan_starts;
984 nursery_section = section;
986 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
990 mono_gc_get_logfile (void)
992 return gc_debug_file;
996 mono_gc_params_set (const char* options)
998 if (gc_params_options)
999 g_free (gc_params_options);
1001 gc_params_options = g_strdup (options);
1005 mono_gc_debug_set (const char* options)
1007 if (gc_debug_options)
1008 g_free (gc_debug_options);
1010 gc_debug_options = g_strdup (options);
1014 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1016 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1017 SgenGrayQueue *queue = ctx.queue;
1020 for (i = 0; i < fin_queue->next_slot; ++i) {
1021 GCObject *obj = (GCObject *)fin_queue->data [i];
1024 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1025 copy_func ((GCObject**)&fin_queue->data [i], queue);
1030 generation_name (int generation)
1032 switch (generation) {
1033 case GENERATION_NURSERY: return "nursery";
1034 case GENERATION_OLD: return "old";
1035 default: g_assert_not_reached ();
1040 sgen_generation_name (int generation)
1042 return generation_name (generation);
1046 finish_gray_stack (int generation, ScanCopyContext ctx)
1050 int done_with_ephemerons, ephemeron_rounds = 0;
1051 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1052 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1053 SgenGrayQueue *queue = ctx.queue;
1055 binary_protocol_finish_gray_stack_start (sgen_timestamp (), generation);
1057 * We copied all the reachable objects. Now it's the time to copy
1058 * the objects that were not referenced by the roots, but by the copied objects.
1059 * we built a stack of objects pointed to by gray_start: they are
1060 * additional roots and we may add more items as we go.
1061 * We loop until gray_start == gray_objects which means no more objects have
1062 * been added. Note this is iterative: no recursion is involved.
1063 * We need to walk the LO list as well in search of marked big objects
1064 * (use a flag since this is needed only on major collections). We need to loop
1065 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1066 * To achieve better cache locality and cache usage, we drain the gray stack
1067 * frequently, after each object is copied, and just finish the work here.
1069 sgen_drain_gray_stack (ctx);
1071 SGEN_LOG (2, "%s generation done", generation_name (generation));
1074 Reset bridge data, we might have lingering data from a previous collection if this is a major
1075 collection trigged by minor overflow.
1077 We must reset the gathered bridges since their original block might be evacuated due to major
1078 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1080 if (sgen_client_bridge_need_processing ())
1081 sgen_client_bridge_reset_data ();
1084 * Mark all strong toggleref objects. This must be done before we walk ephemerons or finalizers
1085 * to ensure they see the full set of live objects.
1087 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1090 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1091 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1092 * objects that are in fact reachable.
1094 done_with_ephemerons = 0;
1096 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1097 sgen_drain_gray_stack (ctx);
1099 } while (!done_with_ephemerons);
1101 if (sgen_client_bridge_need_processing ()) {
1102 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1103 sgen_drain_gray_stack (ctx);
1104 sgen_collect_bridge_objects (generation, ctx);
1105 if (generation == GENERATION_OLD)
1106 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1109 Do the first bridge step here, as the collector liveness state will become useless after that.
1111 An important optimization is to only proccess the possibly dead part of the object graph and skip
1112 over all live objects as we transitively know everything they point must be alive too.
1114 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1116 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1117 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1120 sgen_client_bridge_processing_stw_step ();
1124 Make sure we drain the gray stack before processing disappearing links and finalizers.
1125 If we don't make sure it is empty we might wrongly see a live object as dead.
1127 sgen_drain_gray_stack (ctx);
1130 We must clear weak links that don't track resurrection before processing object ready for
1131 finalization so they can be cleared before that.
1133 sgen_null_link_in_range (generation, ctx, FALSE);
1134 if (generation == GENERATION_OLD)
1135 sgen_null_link_in_range (GENERATION_NURSERY, ctx, FALSE);
1138 /* walk the finalization queue and move also the objects that need to be
1139 * finalized: use the finalized objects as new roots so the objects they depend
1140 * on are also not reclaimed. As with the roots above, only objects in the nursery
1141 * are marked/copied.
1143 sgen_finalize_in_range (generation, ctx);
1144 if (generation == GENERATION_OLD)
1145 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1146 /* drain the new stack that might have been created */
1147 SGEN_LOG (6, "Precise scan of gray area post fin");
1148 sgen_drain_gray_stack (ctx);
1151 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1153 done_with_ephemerons = 0;
1155 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1156 sgen_drain_gray_stack (ctx);
1158 } while (!done_with_ephemerons);
1160 sgen_client_clear_unreachable_ephemerons (ctx);
1163 * We clear togglerefs only after all possible chances of revival are done.
1164 * This is semantically more inline with what users expect and it allows for
1165 * user finalizers to correctly interact with TR objects.
1167 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1170 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);
1173 * handle disappearing links
1174 * Note we do this after checking the finalization queue because if an object
1175 * survives (at least long enough to be finalized) we don't clear the link.
1176 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1177 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1180 g_assert (sgen_gray_object_queue_is_empty (queue));
1182 sgen_null_link_in_range (generation, ctx, TRUE);
1183 if (generation == GENERATION_OLD)
1184 sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
1185 if (sgen_gray_object_queue_is_empty (queue))
1187 sgen_drain_gray_stack (ctx);
1190 g_assert (sgen_gray_object_queue_is_empty (queue));
1192 binary_protocol_finish_gray_stack_end (sgen_timestamp (), generation);
1196 sgen_check_section_scan_starts (GCMemSection *section)
1199 for (i = 0; i < section->num_scan_start; ++i) {
1200 if (section->scan_starts [i]) {
1201 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1202 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1208 check_scan_starts (void)
1210 if (!do_scan_starts_check)
1212 sgen_check_section_scan_starts (nursery_section);
1213 major_collector.check_scan_starts ();
1217 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1221 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
1222 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1223 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1224 } SGEN_HASH_TABLE_FOREACH_END;
1230 static gboolean inited = FALSE;
1235 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1237 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1238 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1239 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1240 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1241 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1242 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1244 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1245 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1246 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1247 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1248 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1249 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1250 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1251 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1252 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1253 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1255 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1257 #ifdef HEAVY_STATISTICS
1258 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1259 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1260 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1261 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1262 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1264 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1265 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1267 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1268 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1269 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1270 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1272 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1273 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1275 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1277 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1278 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1279 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1280 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1282 sgen_nursery_allocator_init_heavy_stats ();
1290 reset_pinned_from_failed_allocation (void)
1292 bytes_pinned_from_failed_allocation = 0;
1296 sgen_set_pinned_from_failed_allocation (mword objsize)
1298 bytes_pinned_from_failed_allocation += objsize;
1302 sgen_collection_is_concurrent (void)
1304 switch (current_collection_generation) {
1305 case GENERATION_NURSERY:
1307 case GENERATION_OLD:
1308 return concurrent_collection_in_progress;
1310 g_error ("Invalid current generation %d", current_collection_generation);
1316 sgen_concurrent_collection_in_progress (void)
1318 return concurrent_collection_in_progress;
1322 SgenThreadPoolJob job;
1323 SgenObjectOperations *ops;
1324 SgenGrayQueue *gc_thread_gray_queue;
1332 static ScanCopyContext
1333 scan_copy_context_for_scan_job (void *worker_data_untyped, ScanJob *job)
1335 WorkerData *worker_data = (WorkerData *)worker_data_untyped;
1337 return CONTEXT_FROM_OBJECT_OPERATIONS (job->ops, sgen_workers_get_job_gray_queue (worker_data, job->gc_thread_gray_queue));
1341 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
1343 remset.scan_remsets (scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job));
1351 } ScanFromRegisteredRootsJob;
1354 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1356 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1357 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1359 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1366 } ScanThreadDataJob;
1369 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1371 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1372 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1374 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1379 SgenPointerQueue *queue;
1380 } ScanFinalizerEntriesJob;
1383 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1385 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1386 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1388 scan_finalizer_entries (job_data->queue, ctx);
1392 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1394 ScanJob *job_data = (ScanJob*)job;
1395 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1397 g_assert (concurrent_collection_in_progress);
1398 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, 0, 1);
1402 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1404 ScanJob *job_data = (ScanJob*)job;
1405 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1407 g_assert (concurrent_collection_in_progress);
1408 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx);
1412 job_major_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1414 ParallelScanJob *job_data = (ParallelScanJob*)job;
1415 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1417 g_assert (concurrent_collection_in_progress);
1419 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1423 job_los_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1425 ScanJob *job_data = (ScanJob*)job;
1426 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1428 g_assert (concurrent_collection_in_progress);
1430 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx);
1434 job_scan_last_pinned (void *worker_data_untyped, SgenThreadPoolJob *job)
1436 ScanJob *job_data = (ScanJob*)job;
1437 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1439 g_assert (concurrent_collection_in_progress);
1441 sgen_scan_pin_queue_objects (ctx);
1445 workers_finish_callback (void)
1448 int split_count = sgen_workers_get_job_split_count ();
1450 /* Mod union preclean jobs */
1451 for (i = 0; i < split_count; i++) {
1452 ParallelScanJob *psj;
1453 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean major mod union cardtable", job_major_mod_union_preclean, sizeof (ParallelScanJob));
1454 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1455 psj->scan_job.gc_thread_gray_queue = NULL;
1457 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1460 sj = (ScanJob*)sgen_thread_pool_job_alloc ("preclean los mod union cardtable", job_los_mod_union_preclean, sizeof (ScanJob));
1461 sj->ops = sgen_workers_get_idle_func_object_ops ();
1462 sj->gc_thread_gray_queue = NULL;
1463 sgen_workers_enqueue_job (&sj->job, TRUE);
1465 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan last pinned", job_scan_last_pinned, sizeof (ScanJob));
1466 sj->ops = sgen_workers_get_idle_func_object_ops ();
1467 sj->gc_thread_gray_queue = NULL;
1468 sgen_workers_enqueue_job (&sj->job, TRUE);
1472 init_gray_queue (SgenGrayQueue *gc_thread_gray_queue, gboolean use_workers)
1475 sgen_workers_init_distribute_gray_queue ();
1476 sgen_gray_object_queue_init (gc_thread_gray_queue, NULL, TRUE);
1480 enqueue_scan_from_roots_jobs (SgenGrayQueue *gc_thread_gray_queue, char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
1482 ScanFromRegisteredRootsJob *scrrj;
1483 ScanThreadDataJob *stdj;
1484 ScanFinalizerEntriesJob *sfej;
1486 /* registered roots, this includes static fields */
1488 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1489 scrrj->scan_job.ops = ops;
1490 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1491 scrrj->heap_start = heap_start;
1492 scrrj->heap_end = heap_end;
1493 scrrj->root_type = ROOT_TYPE_NORMAL;
1494 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1496 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1497 scrrj->scan_job.ops = ops;
1498 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1499 scrrj->heap_start = heap_start;
1500 scrrj->heap_end = heap_end;
1501 scrrj->root_type = ROOT_TYPE_WBARRIER;
1502 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1506 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1507 stdj->scan_job.ops = ops;
1508 stdj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1509 stdj->heap_start = heap_start;
1510 stdj->heap_end = heap_end;
1511 sgen_workers_enqueue_job (&stdj->scan_job.job, enqueue);
1513 /* Scan the list of objects ready for finalization. */
1515 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1516 sfej->scan_job.ops = ops;
1517 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1518 sfej->queue = &fin_ready_queue;
1519 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1521 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1522 sfej->scan_job.ops = ops;
1523 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1524 sfej->queue = &critical_fin_queue;
1525 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1529 * Perform a nursery collection.
1531 * Return whether any objects were late-pinned due to being out of memory.
1534 collect_nursery (const char *reason, gboolean is_overflow, SgenGrayQueue *unpin_queue)
1536 gboolean needs_major;
1537 size_t max_garbage_amount;
1539 mword fragment_total;
1541 SgenGrayQueue gc_thread_gray_queue;
1542 SgenObjectOperations *object_ops;
1543 ScanCopyContext ctx;
1546 SGEN_TV_DECLARE (last_minor_collection_start_tv);
1547 SGEN_TV_DECLARE (last_minor_collection_end_tv);
1549 if (disable_minor_collections)
1552 TV_GETTIME (last_minor_collection_start_tv);
1553 atv = last_minor_collection_start_tv;
1555 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1557 if (sgen_concurrent_collection_in_progress ())
1558 object_ops = &sgen_minor_collector.serial_ops_with_concurrent_major;
1560 object_ops = &sgen_minor_collector.serial_ops;
1562 if (do_verify_nursery || do_dump_nursery_content)
1563 sgen_debug_verify_nursery (do_dump_nursery_content);
1565 current_collection_generation = GENERATION_NURSERY;
1567 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1569 reset_pinned_from_failed_allocation ();
1571 check_scan_starts ();
1573 sgen_nursery_alloc_prepare_for_minor ();
1577 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
1578 /* FIXME: optimize later to use the higher address where an object can be present */
1579 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
1581 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 ()));
1582 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
1583 g_assert (nursery_section->size >= max_garbage_amount);
1585 /* world must be stopped already */
1587 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1589 sgen_client_pre_collection_checks ();
1591 nursery_section->next_data = nursery_next;
1593 major_collector.start_nursery_collection ();
1595 sgen_memgov_minor_collection_start ();
1597 init_gray_queue (&gc_thread_gray_queue, FALSE);
1598 ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gc_thread_gray_queue);
1600 gc_stats.minor_gc_count ++;
1602 sgen_process_fin_stage_entries ();
1604 /* pin from pinned handles */
1605 sgen_init_pinning ();
1606 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1607 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
1608 /* pin cemented objects */
1609 sgen_pin_cemented_objects ();
1610 /* identify pinned objects */
1611 sgen_optimize_pin_queue ();
1612 sgen_pinning_setup_section (nursery_section);
1614 pin_objects_in_nursery (FALSE, ctx);
1615 sgen_pinning_trim_queue_to_section (nursery_section);
1617 if (remset_consistency_checks)
1618 sgen_check_remset_consistency ();
1620 if (whole_heap_check_before_collection) {
1621 sgen_clear_nursery_fragments ();
1622 sgen_check_whole_heap (FALSE);
1626 time_minor_pinning += TV_ELAPSED (btv, atv);
1627 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (btv, atv));
1628 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1630 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
1631 sj->ops = object_ops;
1632 sj->gc_thread_gray_queue = &gc_thread_gray_queue;
1633 sgen_workers_enqueue_job (&sj->job, FALSE);
1635 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1637 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1638 SGEN_LOG (2, "Old generation scan: %lld usecs", (long long)TV_ELAPSED (atv, btv));
1640 sgen_pin_stats_report ();
1642 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1643 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1646 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1648 enqueue_scan_from_roots_jobs (&gc_thread_gray_queue, sgen_get_nursery_start (), nursery_next, object_ops, FALSE);
1651 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1653 finish_gray_stack (GENERATION_NURSERY, ctx);
1656 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1657 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1659 if (objects_pinned) {
1660 sgen_optimize_pin_queue ();
1661 sgen_pinning_setup_section (nursery_section);
1665 * This is the latest point at which we can do this check, because
1666 * sgen_build_nursery_fragments() unpins nursery objects again.
1668 if (remset_consistency_checks)
1669 sgen_check_remset_consistency ();
1671 /* walk the pin_queue, build up the fragment list of free memory, unmark
1672 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1675 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1676 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1677 if (!fragment_total)
1680 /* Clear TLABs for all threads */
1681 sgen_clear_tlabs ();
1683 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1685 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1686 SGEN_LOG (2, "Fragment creation: %lld usecs, %lu bytes available", (long long)TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1688 if (remset_consistency_checks)
1689 sgen_check_major_refs ();
1691 major_collector.finish_nursery_collection ();
1693 TV_GETTIME (last_minor_collection_end_tv);
1694 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1696 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1698 /* prepare the pin queue for the next collection */
1699 sgen_finish_pinning ();
1700 if (sgen_have_pending_finalizers ()) {
1701 SGEN_LOG (4, "Finalizer-thread wakeup");
1702 sgen_client_finalize_notify ();
1704 sgen_pin_stats_reset ();
1705 /* clear cemented hash */
1706 sgen_cement_clear_below_threshold ();
1708 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
1710 remset.finish_minor_collection ();
1712 check_scan_starts ();
1714 binary_protocol_flush_buffers (FALSE);
1716 sgen_memgov_minor_collection_end (reason, is_overflow);
1718 /*objects are late pinned because of lack of memory, so a major is a good call*/
1719 needs_major = objects_pinned > 0;
1720 current_collection_generation = -1;
1723 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1725 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1726 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1732 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1733 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1734 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1735 } CopyOrMarkFromRootsMode;
1738 major_copy_or_mark_from_roots (SgenGrayQueue *gc_thread_gray_queue, size_t *old_next_pin_slot, CopyOrMarkFromRootsMode mode, SgenObjectOperations *object_ops)
1743 /* FIXME: only use these values for the precise scan
1744 * note that to_space pointers should be excluded anyway...
1746 char *heap_start = NULL;
1747 char *heap_end = (char*)-1;
1748 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, gc_thread_gray_queue);
1749 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1751 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1753 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1754 /*This cleans up unused fragments */
1755 sgen_nursery_allocator_prepare_for_pinning ();
1757 if (do_concurrent_checks)
1758 sgen_debug_check_nursery_is_clean ();
1760 /* The concurrent collector doesn't touch the nursery. */
1761 sgen_nursery_alloc_prepare_for_major ();
1766 /* Pinning depends on this */
1767 sgen_clear_nursery_fragments ();
1769 if (whole_heap_check_before_collection)
1770 sgen_check_whole_heap (TRUE);
1773 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1775 if (!sgen_collection_is_concurrent ())
1776 nursery_section->next_data = sgen_get_nursery_end ();
1777 /* we should also coalesce scanning from sections close to each other
1778 * and deal with pointers outside of the sections later.
1783 sgen_client_pre_collection_checks ();
1785 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1786 /* Remsets are not useful for a major collection */
1787 remset.clear_cards ();
1790 sgen_process_fin_stage_entries ();
1793 sgen_init_pinning ();
1794 SGEN_LOG (6, "Collecting pinned addresses");
1795 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1796 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1797 /* Pin cemented objects that were forced */
1798 sgen_pin_cemented_objects ();
1800 sgen_optimize_pin_queue ();
1801 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1803 * Cemented objects that are in the pinned list will be marked. When
1804 * marking concurrently we won't mark mod-union cards for these objects.
1805 * Instead they will remain cemented until the next major collection,
1806 * when we will recheck if they are still pinned in the roots.
1808 sgen_cement_force_pinned ();
1811 sgen_client_collecting_major_1 ();
1814 * pin_queue now contains all candidate pointers, sorted and
1815 * uniqued. We must do two passes now to figure out which
1816 * objects are pinned.
1818 * The first is to find within the pin_queue the area for each
1819 * section. This requires that the pin_queue be sorted. We
1820 * also process the LOS objects and pinned chunks here.
1822 * The second, destructive, pass is to reduce the section
1823 * areas to pointers to the actually pinned objects.
1825 SGEN_LOG (6, "Pinning from sections");
1826 /* first pass for the sections */
1827 sgen_find_section_pin_queue_start_end (nursery_section);
1828 /* identify possible pointers to the insize of large objects */
1829 SGEN_LOG (6, "Pinning from large objects");
1830 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1832 if (sgen_find_optimized_pin_queue_area ((char*)bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1833 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
1835 if (sgen_los_object_is_pinned (bigobj->data)) {
1836 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1839 sgen_los_pin_object (bigobj->data);
1840 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1841 GRAY_OBJECT_ENQUEUE (gc_thread_gray_queue, bigobj->data, sgen_obj_get_descriptor ((GCObject*)bigobj->data));
1842 sgen_pin_stats_register_object (bigobj->data, GENERATION_OLD);
1843 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1844 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1845 (unsigned long)sgen_los_object_size (bigobj));
1847 sgen_client_pinned_los_object (bigobj->data);
1851 pin_objects_in_nursery (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT, ctx);
1852 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1853 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1855 major_collector.pin_objects (gc_thread_gray_queue);
1856 if (old_next_pin_slot)
1857 *old_next_pin_slot = sgen_get_pinned_count ();
1860 time_major_pinning += TV_ELAPSED (atv, btv);
1861 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (atv, btv));
1862 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1864 major_collector.init_to_space ();
1866 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1867 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1868 if (sgen_workers_have_idle_work ()) {
1870 * We force the finish of the worker with the new object ops context
1871 * which can also do copying. We need to have finished pinning.
1873 /* FIXME Implement parallel copying and get rid of this ineffective hack */
1874 if (major_collector.is_parallel)
1875 sgen_workers_start_all_workers (&major_collector.major_ops_conc_par_start, NULL);
1877 sgen_workers_start_all_workers (object_ops, NULL);
1879 sgen_workers_join ();
1883 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1884 main_gc_thread = mono_native_thread_self ();
1887 sgen_client_collecting_major_2 ();
1890 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1892 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1894 enqueue_scan_from_roots_jobs (gc_thread_gray_queue, heap_start, heap_end, object_ops, FALSE);
1897 time_major_scan_roots += TV_ELAPSED (atv, btv);
1900 * We start the concurrent worker after pinning and after we scanned the roots
1901 * in order to make sure that the worker does not finish before handling all
1904 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1905 if (precleaning_enabled) {
1906 sgen_workers_start_all_workers (object_ops, workers_finish_callback);
1908 sgen_workers_start_all_workers (object_ops, NULL);
1910 gray_queue_enable_redirect (gc_thread_gray_queue);
1913 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1916 /* Mod union card table */
1917 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ScanJob));
1918 sj->ops = object_ops;
1919 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1920 sgen_workers_enqueue_job (&sj->job, FALSE);
1922 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ScanJob));
1923 sj->ops = object_ops;
1924 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1925 sgen_workers_enqueue_job (&sj->job, FALSE);
1928 time_major_scan_mod_union += TV_ELAPSED (btv, atv);
1931 sgen_pin_stats_report ();
1933 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1934 sgen_finish_pinning ();
1936 sgen_pin_stats_reset ();
1938 if (do_concurrent_checks)
1939 sgen_debug_check_nursery_is_clean ();
1944 major_start_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean concurrent, size_t *old_next_pin_slot)
1946 SgenObjectOperations *object_ops;
1948 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
1950 current_collection_generation = GENERATION_OLD;
1952 sgen_workers_assert_gray_queue_is_empty ();
1955 sgen_cement_reset ();
1958 g_assert (major_collector.is_concurrent);
1959 concurrent_collection_in_progress = TRUE;
1961 if (major_collector.is_parallel)
1962 object_ops = &major_collector.major_ops_conc_par_start;
1964 object_ops = &major_collector.major_ops_concurrent_start;
1967 object_ops = &major_collector.major_ops_serial;
1970 reset_pinned_from_failed_allocation ();
1972 sgen_memgov_major_collection_start (concurrent, reason);
1974 //count_ref_nonref_objs ();
1975 //consistency_check ();
1977 check_scan_starts ();
1980 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
1981 gc_stats.major_gc_count ++;
1983 if (major_collector.start_major_collection)
1984 major_collector.start_major_collection ();
1986 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);
1990 major_finish_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean is_overflow, size_t old_next_pin_slot, gboolean forced)
1992 ScannedObjectCounts counts;
1993 SgenObjectOperations *object_ops;
1994 mword fragment_total;
2000 if (concurrent_collection_in_progress) {
2001 if (major_collector.is_parallel)
2002 object_ops = &major_collector.major_ops_conc_par_finish;
2004 object_ops = &major_collector.major_ops_concurrent_finish;
2006 major_copy_or_mark_from_roots (gc_thread_gray_queue, NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, object_ops);
2008 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2009 main_gc_thread = NULL;
2012 object_ops = &major_collector.major_ops_serial;
2015 sgen_workers_assert_gray_queue_is_empty ();
2017 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, gc_thread_gray_queue));
2019 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2021 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2023 if (objects_pinned) {
2024 g_assert (!concurrent_collection_in_progress);
2027 * This is slow, but we just OOM'd.
2029 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2030 * queue is laid out at this point.
2032 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2034 * We need to reestablish all pinned nursery objects in the pin queue
2035 * because they're needed for fragment creation. Unpinning happens by
2036 * walking the whole queue, so it's not necessary to reestablish where major
2037 * heap block pins are - all we care is that they're still in there
2040 sgen_optimize_pin_queue ();
2041 sgen_find_section_pin_queue_start_end (nursery_section);
2045 reset_heap_boundaries ();
2046 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2048 /* walk the pin_queue, build up the fragment list of free memory, unmark
2049 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2052 fragment_total = sgen_build_nursery_fragments (nursery_section, NULL);
2053 if (!fragment_total)
2055 SGEN_LOG (4, "Free space in nursery after major %ld", (long)fragment_total);
2057 if (do_concurrent_checks && concurrent_collection_in_progress)
2058 sgen_debug_check_nursery_is_clean ();
2060 /* prepare the pin queue for the next collection */
2061 sgen_finish_pinning ();
2063 /* Clear TLABs for all threads */
2064 sgen_clear_tlabs ();
2066 sgen_pin_stats_reset ();
2068 sgen_cement_clear_below_threshold ();
2070 if (check_mark_bits_after_major_collection)
2071 sgen_check_heap_marked (concurrent_collection_in_progress);
2074 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2076 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2077 sgen_memgov_major_pre_sweep ();
2080 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2085 time_major_los_sweep += TV_ELAPSED (atv, btv);
2087 major_collector.sweep ();
2089 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2092 time_major_sweep += TV_ELAPSED (btv, atv);
2094 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2096 if (sgen_have_pending_finalizers ()) {
2097 SGEN_LOG (4, "Finalizer-thread wakeup");
2098 sgen_client_finalize_notify ();
2101 sgen_memgov_major_collection_end (forced, concurrent_collection_in_progress, reason, is_overflow);
2102 current_collection_generation = -1;
2104 memset (&counts, 0, sizeof (ScannedObjectCounts));
2105 major_collector.finish_major_collection (&counts);
2107 sgen_workers_assert_gray_queue_is_empty ();
2109 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2110 if (concurrent_collection_in_progress)
2111 concurrent_collection_in_progress = FALSE;
2113 check_scan_starts ();
2115 binary_protocol_flush_buffers (FALSE);
2117 //consistency_check ();
2119 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2123 major_do_collection (const char *reason, gboolean is_overflow, gboolean forced)
2125 TV_DECLARE (time_start);
2126 TV_DECLARE (time_end);
2127 size_t old_next_pin_slot;
2128 SgenGrayQueue gc_thread_gray_queue;
2130 if (disable_major_collections)
2133 if (major_collector.get_and_reset_num_major_objects_marked) {
2134 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2135 g_assert (!num_marked);
2138 /* world must be stopped already */
2139 TV_GETTIME (time_start);
2141 init_gray_queue (&gc_thread_gray_queue, FALSE);
2142 major_start_collection (&gc_thread_gray_queue, reason, FALSE, &old_next_pin_slot);
2143 major_finish_collection (&gc_thread_gray_queue, reason, is_overflow, old_next_pin_slot, forced);
2144 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2146 TV_GETTIME (time_end);
2147 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2149 /* FIXME: also report this to the user, preferably in gc-end. */
2150 if (major_collector.get_and_reset_num_major_objects_marked)
2151 major_collector.get_and_reset_num_major_objects_marked ();
2153 return bytes_pinned_from_failed_allocation > 0;
2157 major_start_concurrent_collection (const char *reason)
2159 TV_DECLARE (time_start);
2160 TV_DECLARE (time_end);
2161 long long num_objects_marked;
2162 SgenGrayQueue gc_thread_gray_queue;
2164 if (disable_major_collections)
2167 TV_GETTIME (time_start);
2168 SGEN_TV_GETTIME (time_major_conc_collection_start);
2170 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2171 g_assert (num_objects_marked == 0);
2173 binary_protocol_concurrent_start ();
2175 init_gray_queue (&gc_thread_gray_queue, TRUE);
2176 // FIXME: store reason and pass it when finishing
2177 major_start_collection (&gc_thread_gray_queue, reason, TRUE, NULL);
2178 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2180 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2182 TV_GETTIME (time_end);
2183 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2185 current_collection_generation = -1;
2189 * Returns whether the major collection has finished.
2192 major_should_finish_concurrent_collection (void)
2194 return sgen_workers_all_done ();
2198 major_update_concurrent_collection (void)
2200 TV_DECLARE (total_start);
2201 TV_DECLARE (total_end);
2203 TV_GETTIME (total_start);
2205 binary_protocol_concurrent_update ();
2207 major_collector.update_cardtable_mod_union ();
2208 sgen_los_update_cardtable_mod_union ();
2210 TV_GETTIME (total_end);
2211 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2215 major_finish_concurrent_collection (gboolean forced)
2217 SgenGrayQueue gc_thread_gray_queue;
2218 TV_DECLARE (total_start);
2219 TV_DECLARE (total_end);
2221 TV_GETTIME (total_start);
2223 binary_protocol_concurrent_finish ();
2226 * We need to stop all workers since we're updating the cardtable below.
2227 * The workers will be resumed with a finishing pause context to avoid
2228 * additional cardtable and object scanning.
2230 sgen_workers_stop_all_workers ();
2232 SGEN_TV_GETTIME (time_major_conc_collection_end);
2233 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2235 major_collector.update_cardtable_mod_union ();
2236 sgen_los_update_cardtable_mod_union ();
2238 if (mod_union_consistency_check)
2239 sgen_check_mod_union_consistency ();
2241 current_collection_generation = GENERATION_OLD;
2242 sgen_cement_reset ();
2243 init_gray_queue (&gc_thread_gray_queue, FALSE);
2244 major_finish_collection (&gc_thread_gray_queue, "finishing", FALSE, -1, forced);
2245 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2247 TV_GETTIME (total_end);
2248 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2250 current_collection_generation = -1;
2254 * Ensure an allocation request for @size will succeed by freeing enough memory.
2256 * LOCKING: The GC lock MUST be held.
2259 sgen_ensure_free_space (size_t size, int generation)
2261 int generation_to_collect = -1;
2262 const char *reason = NULL;
2264 if (generation == GENERATION_OLD) {
2265 if (sgen_need_major_collection (size)) {
2266 reason = "LOS overflow";
2267 generation_to_collect = GENERATION_OLD;
2270 if (degraded_mode) {
2271 if (sgen_need_major_collection (size)) {
2272 reason = "Degraded mode overflow";
2273 generation_to_collect = GENERATION_OLD;
2275 } else if (sgen_need_major_collection (size)) {
2276 reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
2277 generation_to_collect = GENERATION_OLD;
2279 generation_to_collect = GENERATION_NURSERY;
2280 reason = "Nursery full";
2284 if (generation_to_collect == -1) {
2285 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2286 generation_to_collect = GENERATION_OLD;
2287 reason = "Finish concurrent collection";
2291 if (generation_to_collect == -1)
2293 sgen_perform_collection (size, generation_to_collect, reason, FALSE, TRUE);
2297 * LOCKING: Assumes the GC lock is held.
2300 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw)
2302 TV_DECLARE (gc_total_start);
2303 TV_DECLARE (gc_total_end);
2304 int overflow_generation_to_collect = -1;
2305 int oldest_generation_collected = generation_to_collect;
2306 const char *overflow_reason = NULL;
2307 gboolean finish_concurrent = concurrent_collection_in_progress && (major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD);
2309 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2311 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2314 sgen_stop_world (generation_to_collect);
2316 SGEN_ASSERT (0, sgen_is_world_stopped (), "We can only collect if the world is stopped");
2319 TV_GETTIME (gc_total_start);
2321 // FIXME: extract overflow reason
2322 // FIXME: minor overflow for concurrent case
2323 if (generation_to_collect == GENERATION_NURSERY && !finish_concurrent) {
2324 if (concurrent_collection_in_progress)
2325 major_update_concurrent_collection ();
2327 if (collect_nursery (reason, FALSE, NULL) && !concurrent_collection_in_progress) {
2328 overflow_generation_to_collect = GENERATION_OLD;
2329 overflow_reason = "Minor overflow";
2331 } else if (finish_concurrent) {
2332 major_finish_concurrent_collection (wait_to_finish);
2333 oldest_generation_collected = GENERATION_OLD;
2335 SGEN_ASSERT (0, generation_to_collect == GENERATION_OLD, "We should have handled nursery collections above");
2336 if (major_collector.is_concurrent && !wait_to_finish) {
2337 collect_nursery ("Concurrent start", FALSE, NULL);
2338 major_start_concurrent_collection (reason);
2339 oldest_generation_collected = GENERATION_NURSERY;
2340 } else if (major_do_collection (reason, FALSE, wait_to_finish)) {
2341 overflow_generation_to_collect = GENERATION_NURSERY;
2342 overflow_reason = "Excessive pinning";
2346 if (overflow_generation_to_collect != -1) {
2347 SGEN_ASSERT (0, !concurrent_collection_in_progress, "We don't yet support overflow collections with the concurrent collector");
2350 * We need to do an overflow collection, either because we ran out of memory
2351 * or the nursery is fully pinned.
2354 if (overflow_generation_to_collect == GENERATION_NURSERY)
2355 collect_nursery (overflow_reason, TRUE, NULL);
2357 major_do_collection (overflow_reason, TRUE, wait_to_finish);
2359 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2362 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2364 /* this also sets the proper pointers for the next allocation */
2365 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2366 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2367 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2368 sgen_dump_pin_queue ();
2372 TV_GETTIME (gc_total_end);
2373 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2376 sgen_restart_world (oldest_generation_collected);
2380 * ######################################################################
2381 * ######## Memory allocation from the OS
2382 * ######################################################################
2383 * This section of code deals with getting memory from the OS and
2384 * allocating memory for GC-internal data structures.
2385 * Internal memory can be handled with a freelist for small objects.
2391 G_GNUC_UNUSED static void
2392 report_internal_mem_usage (void)
2394 printf ("Internal memory usage:\n");
2395 sgen_report_internal_mem_usage ();
2396 printf ("Pinned memory usage:\n");
2397 major_collector.report_pinned_memory_usage ();
2401 * ######################################################################
2402 * ######## Finalization support
2403 * ######################################################################
2407 * If the object has been forwarded it means it's still referenced from a root.
2408 * If it is pinned it's still alive as well.
2409 * A LOS object is only alive if we have pinned it.
2410 * Return TRUE if @obj is ready to be finalized.
2412 static inline gboolean
2413 sgen_is_object_alive (GCObject *object)
2415 if (ptr_in_nursery (object))
2416 return sgen_nursery_is_object_alive (object);
2418 return sgen_major_is_object_alive (object);
2422 * This function returns true if @object is either alive and belongs to the
2423 * current collection - major collections are full heap, so old gen objects
2424 * are never alive during a minor collection.
2427 sgen_is_object_alive_and_on_current_collection (GCObject *object)
2429 if (ptr_in_nursery (object))
2430 return sgen_nursery_is_object_alive (object);
2432 if (current_collection_generation == GENERATION_NURSERY)
2435 return sgen_major_is_object_alive (object);
2440 sgen_gc_is_object_ready_for_finalization (GCObject *object)
2442 return !sgen_is_object_alive (object);
2446 sgen_queue_finalization_entry (GCObject *obj)
2448 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2450 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2452 sgen_client_object_queued_for_finalization (obj);
2456 sgen_object_is_live (GCObject *obj)
2458 return sgen_is_object_alive_and_on_current_collection (obj);
2462 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2463 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2464 * all finalizers have really finished running.
2466 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2467 * This means that just checking whether the queues are empty leaves the possibility that an
2468 * object might have been dequeued but not yet finalized. That's why we need the additional
2469 * flag `pending_unqueued_finalizer`.
2472 static volatile gboolean pending_unqueued_finalizer = FALSE;
2473 volatile gboolean sgen_suspend_finalizers = FALSE;
2476 sgen_set_suspend_finalizers (void)
2478 sgen_suspend_finalizers = TRUE;
2482 sgen_gc_invoke_finalizers (void)
2486 g_assert (!pending_unqueued_finalizer);
2488 /* FIXME: batch to reduce lock contention */
2489 while (sgen_have_pending_finalizers ()) {
2495 * We need to set `pending_unqueued_finalizer` before dequeing the
2496 * finalizable object.
2498 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2499 pending_unqueued_finalizer = TRUE;
2500 mono_memory_write_barrier ();
2501 obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
2502 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2503 pending_unqueued_finalizer = TRUE;
2504 mono_memory_write_barrier ();
2505 obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
2511 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2519 /* the object is on the stack so it is pinned */
2520 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2521 sgen_client_run_finalize (obj);
2524 if (pending_unqueued_finalizer) {
2525 mono_memory_write_barrier ();
2526 pending_unqueued_finalizer = FALSE;
2533 sgen_have_pending_finalizers (void)
2535 if (sgen_suspend_finalizers)
2537 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2541 * ######################################################################
2542 * ######## registered roots support
2543 * ######################################################################
2547 * We do not coalesce roots.
2550 sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg)
2552 RootRecord new_root;
2555 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2556 RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
2557 /* we allow changing the size and the descriptor (for thread statics etc) */
2559 size_t old_size = root->end_root - start;
2560 root->end_root = start + size;
2561 SGEN_ASSERT (0, !!root->root_desc == !!descr, "Can't change whether a root is precise or conservative.");
2562 SGEN_ASSERT (0, root->source == source, "Can't change a root's source identifier.");
2563 SGEN_ASSERT (0, !!root->msg == !!msg, "Can't change a root's message.");
2564 root->root_desc = descr;
2566 roots_size -= old_size;
2572 new_root.end_root = start + size;
2573 new_root.root_desc = descr;
2574 new_root.source = source;
2577 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2580 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);
2587 sgen_deregister_root (char* addr)
2593 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2594 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2595 roots_size -= (root.end_root - addr);
2601 * ######################################################################
2602 * ######## Thread handling (stop/start code)
2603 * ######################################################################
2607 sgen_get_current_collection_generation (void)
2609 return current_collection_generation;
2613 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2615 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2617 sgen_client_thread_register (info, stack_bottom_fallback);
2623 sgen_thread_unregister (SgenThreadInfo *p)
2625 sgen_client_thread_unregister (p);
2629 * ######################################################################
2630 * ######## Write barriers
2631 * ######################################################################
2635 * Note: the write barriers first do the needed GC work and then do the actual store:
2636 * this way the value is visible to the conservative GC scan after the write barrier
2637 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2638 * the conservative scan, otherwise by the remembered set scan.
2642 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2644 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2645 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2646 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2647 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2651 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2652 if (binary_protocol_is_heavy_enabled ()) {
2654 for (i = 0; i < count; ++i) {
2655 gpointer dest = (gpointer*)dest_ptr + i;
2656 gpointer obj = *((gpointer*)src_ptr + i);
2658 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2663 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2667 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2671 HEAVY_STAT (++stat_wbarrier_generic_store);
2673 sgen_client_wbarrier_generic_nostore_check (ptr);
2675 obj = *(gpointer*)ptr;
2677 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2680 * We need to record old->old pointer locations for the
2681 * concurrent collector.
2683 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2684 SGEN_LOG (8, "Skipping remset at %p", ptr);
2688 SGEN_LOG (8, "Adding remset at %p", ptr);
2690 remset.wbarrier_generic_nostore (ptr);
2694 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2696 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2697 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2698 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2699 mono_gc_wbarrier_generic_nostore (ptr);
2700 sgen_dummy_use (value);
2703 /* Same as mono_gc_wbarrier_generic_store () but performs the store
2704 * as an atomic operation with release semantics.
2707 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2709 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2711 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2713 InterlockedWritePointer ((volatile gpointer *)ptr, value);
2715 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2716 mono_gc_wbarrier_generic_nostore (ptr);
2718 sgen_dummy_use (value);
2722 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
2724 GCObject **dest = (GCObject **)_dest;
2725 GCObject **src = (GCObject **)_src;
2729 mono_gc_wbarrier_generic_store (dest, *src);
2734 size -= SIZEOF_VOID_P;
2740 * ######################################################################
2741 * ######## Other mono public interface functions.
2742 * ######################################################################
2746 sgen_gc_collect (int generation)
2751 sgen_perform_collection (0, generation, "user request", TRUE, TRUE);
2756 sgen_gc_collection_count (int generation)
2758 if (generation == 0)
2759 return gc_stats.minor_gc_count;
2760 return gc_stats.major_gc_count;
2764 sgen_gc_get_used_size (void)
2768 tot = los_memory_usage;
2769 tot += nursery_section->next_data - nursery_section->data;
2770 tot += major_collector.get_used_size ();
2771 /* FIXME: account for pinned objects */
2777 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2781 va_start (ap, description_format);
2783 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2784 vfprintf (stderr, description_format, ap);
2786 fprintf (stderr, " - %s", fallback);
2787 fprintf (stderr, "\n");
2793 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2796 double val = strtod (opt, &endptr);
2797 if (endptr == opt) {
2798 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2801 else if (val < min || val > max) {
2802 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
2814 char *major_collector_opt = NULL;
2815 char *minor_collector_opt = NULL;
2816 char *params_opts = NULL;
2817 char *debug_opts = NULL;
2818 size_t max_heap = 0;
2819 size_t soft_limit = 0;
2821 gboolean debug_print_allowance = FALSE;
2822 double allowance_ratio = 0, save_target = 0;
2823 gboolean cement_enabled = TRUE;
2826 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
2829 /* already inited */
2832 /* being inited by another thread */
2833 mono_thread_info_usleep (1000);
2836 /* we will init it */
2839 g_assert_not_reached ();
2841 } while (result != 0);
2843 SGEN_TV_GETTIME (sgen_init_timestamp);
2845 #ifdef SGEN_WITHOUT_MONO
2846 mono_thread_smr_init ();
2849 mono_coop_mutex_init (&gc_mutex);
2851 gc_debug_file = stderr;
2853 mono_coop_mutex_init (&sgen_interruption_mutex);
2855 if ((env = g_getenv (MONO_GC_PARAMS_NAME)) || gc_params_options) {
2856 params_opts = g_strdup_printf ("%s,%s", gc_params_options ? gc_params_options : "", env ? env : "");
2860 opts = g_strsplit (params_opts, ",", -1);
2861 for (ptr = opts; *ptr; ++ptr) {
2863 if (g_str_has_prefix (opt, "major=")) {
2864 opt = strchr (opt, '=') + 1;
2865 major_collector_opt = g_strdup (opt);
2866 } else if (g_str_has_prefix (opt, "minor=")) {
2867 opt = strchr (opt, '=') + 1;
2868 minor_collector_opt = g_strdup (opt);
2876 sgen_init_internal_allocator ();
2877 sgen_init_nursery_allocator ();
2878 sgen_init_fin_weak_hash ();
2879 sgen_init_hash_table ();
2880 sgen_init_descriptors ();
2881 sgen_init_gray_queues ();
2882 sgen_init_allocator ();
2883 sgen_init_gchandles ();
2885 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
2886 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
2888 sgen_client_init ();
2890 if (!minor_collector_opt) {
2891 sgen_simple_nursery_init (&sgen_minor_collector);
2893 if (!strcmp (minor_collector_opt, "simple")) {
2895 sgen_simple_nursery_init (&sgen_minor_collector);
2896 } else if (!strcmp (minor_collector_opt, "split")) {
2897 sgen_split_nursery_init (&sgen_minor_collector);
2899 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
2900 goto use_simple_nursery;
2904 if (!major_collector_opt) {
2906 DEFAULT_MAJOR_INIT (&major_collector);
2907 } else if (!strcmp (major_collector_opt, "marksweep")) {
2908 sgen_marksweep_init (&major_collector);
2909 } else if (!strcmp (major_collector_opt, "marksweep-conc")) {
2910 sgen_marksweep_conc_init (&major_collector);
2911 } else if (!strcmp (major_collector_opt, "marksweep-conc-par")) {
2912 sgen_marksweep_conc_par_init (&major_collector);
2914 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `" DEFAULT_MAJOR_NAME "` instead.", "Unknown major collector `%s'.", major_collector_opt);
2915 goto use_default_major;
2918 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
2921 gboolean usage_printed = FALSE;
2923 for (ptr = opts; *ptr; ++ptr) {
2925 if (!strcmp (opt, ""))
2927 if (g_str_has_prefix (opt, "major="))
2929 if (g_str_has_prefix (opt, "minor="))
2931 if (g_str_has_prefix (opt, "max-heap-size=")) {
2932 size_t page_size = mono_pagesize ();
2933 size_t max_heap_candidate = 0;
2934 opt = strchr (opt, '=') + 1;
2935 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
2936 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
2937 if (max_heap != max_heap_candidate)
2938 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
2940 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
2944 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
2945 opt = strchr (opt, '=') + 1;
2946 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
2947 if (soft_limit <= 0) {
2948 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
2952 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
2958 if (g_str_has_prefix (opt, "nursery-size=")) {
2960 opt = strchr (opt, '=') + 1;
2961 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
2962 if ((val & (val - 1))) {
2963 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
2967 if (val < SGEN_MAX_NURSERY_WASTE) {
2968 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
2969 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
2973 sgen_nursery_size = val;
2974 sgen_nursery_bits = 0;
2975 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
2978 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
2984 if (g_str_has_prefix (opt, "save-target-ratio=")) {
2986 opt = strchr (opt, '=') + 1;
2987 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
2988 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
2993 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
2995 opt = strchr (opt, '=') + 1;
2996 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
2997 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
2998 allowance_ratio = val;
3003 if (!strcmp (opt, "cementing")) {
3004 cement_enabled = TRUE;
3007 if (!strcmp (opt, "no-cementing")) {
3008 cement_enabled = FALSE;
3012 if (!strcmp (opt, "precleaning")) {
3013 precleaning_enabled = TRUE;
3016 if (!strcmp (opt, "no-precleaning")) {
3017 precleaning_enabled = FALSE;
3021 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3024 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3027 if (sgen_client_handle_gc_param (opt))
3030 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3035 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3036 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3037 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3038 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3039 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3040 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3041 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3042 fprintf (stderr, " [no-]cementing\n");
3043 if (major_collector.print_gc_param_usage)
3044 major_collector.print_gc_param_usage ();
3045 if (sgen_minor_collector.print_gc_param_usage)
3046 sgen_minor_collector.print_gc_param_usage ();
3047 sgen_client_print_gc_params_usage ();
3048 fprintf (stderr, " Experimental options:\n");
3049 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3050 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);
3051 fprintf (stderr, "\n");
3053 usage_printed = TRUE;
3058 if (major_collector_opt)
3059 g_free (major_collector_opt);
3061 if (minor_collector_opt)
3062 g_free (minor_collector_opt);
3065 g_free (params_opts);
3069 sgen_pinning_init ();
3070 sgen_cement_init (cement_enabled);
3072 if ((env = g_getenv (MONO_GC_DEBUG_NAME)) || gc_debug_options) {
3073 debug_opts = g_strdup_printf ("%s,%s", gc_debug_options ? gc_debug_options : "", env ? env : "");
3077 gboolean usage_printed = FALSE;
3079 opts = g_strsplit (debug_opts, ",", -1);
3080 for (ptr = opts; ptr && *ptr; ptr ++) {
3082 if (!strcmp (opt, ""))
3084 if (opt [0] >= '0' && opt [0] <= '9') {
3085 gc_debug_level = atoi (opt);
3090 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3091 gc_debug_file = fopen (rf, "wb");
3093 gc_debug_file = stderr;
3096 } else if (!strcmp (opt, "print-allowance")) {
3097 debug_print_allowance = TRUE;
3098 } else if (!strcmp (opt, "print-pinning")) {
3099 sgen_pin_stats_enable ();
3100 } else if (!strcmp (opt, "verify-before-allocs")) {
3101 verify_before_allocs = 1;
3102 has_per_allocation_action = TRUE;
3103 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3104 char *arg = strchr (opt, '=') + 1;
3105 verify_before_allocs = atoi (arg);
3106 has_per_allocation_action = TRUE;
3107 } else if (!strcmp (opt, "collect-before-allocs")) {
3108 collect_before_allocs = 1;
3109 has_per_allocation_action = TRUE;
3110 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3111 char *arg = strchr (opt, '=') + 1;
3112 has_per_allocation_action = TRUE;
3113 collect_before_allocs = atoi (arg);
3114 } else if (!strcmp (opt, "verify-before-collections")) {
3115 whole_heap_check_before_collection = TRUE;
3116 } else if (!strcmp (opt, "check-remset-consistency")) {
3117 remset_consistency_checks = TRUE;
3118 nursery_clear_policy = CLEAR_AT_GC;
3119 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3120 if (!major_collector.is_concurrent) {
3121 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3124 mod_union_consistency_check = TRUE;
3125 } else if (!strcmp (opt, "check-mark-bits")) {
3126 check_mark_bits_after_major_collection = TRUE;
3127 } else if (!strcmp (opt, "check-nursery-pinned")) {
3128 check_nursery_objects_pinned = TRUE;
3129 } else if (!strcmp (opt, "clear-at-gc")) {
3130 nursery_clear_policy = CLEAR_AT_GC;
3131 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3132 nursery_clear_policy = CLEAR_AT_GC;
3133 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3134 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3135 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3136 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3137 } else if (!strcmp (opt, "check-scan-starts")) {
3138 do_scan_starts_check = TRUE;
3139 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3140 do_verify_nursery = TRUE;
3141 } else if (!strcmp (opt, "check-concurrent")) {
3142 if (!major_collector.is_concurrent) {
3143 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3146 nursery_clear_policy = CLEAR_AT_GC;
3147 do_concurrent_checks = TRUE;
3148 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3149 do_dump_nursery_content = TRUE;
3150 } else if (!strcmp (opt, "disable-minor")) {
3151 disable_minor_collections = TRUE;
3152 } else if (!strcmp (opt, "disable-major")) {
3153 disable_major_collections = TRUE;
3154 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3155 char *filename = strchr (opt, '=') + 1;
3156 nursery_clear_policy = CLEAR_AT_GC;
3157 sgen_debug_enable_heap_dump (filename);
3158 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3159 char *filename = strchr (opt, '=') + 1;
3160 char *colon = strrchr (filename, ':');
3163 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3164 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3169 binary_protocol_init (filename, (long long)limit);
3170 } else if (!strcmp (opt, "nursery-canaries")) {
3171 do_verify_nursery = TRUE;
3172 enable_nursery_canaries = TRUE;
3173 } else if (!sgen_client_handle_gc_debug (opt)) {
3174 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3179 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);
3180 fprintf (stderr, "Valid <option>s are:\n");
3181 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3182 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3183 fprintf (stderr, " check-remset-consistency\n");
3184 fprintf (stderr, " check-mark-bits\n");
3185 fprintf (stderr, " check-nursery-pinned\n");
3186 fprintf (stderr, " verify-before-collections\n");
3187 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3188 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3189 fprintf (stderr, " disable-minor\n");
3190 fprintf (stderr, " disable-major\n");
3191 fprintf (stderr, " check-concurrent\n");
3192 fprintf (stderr, " clear-[nursery-]at-gc\n");
3193 fprintf (stderr, " clear-at-tlab-creation\n");
3194 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3195 fprintf (stderr, " check-scan-starts\n");
3196 fprintf (stderr, " print-allowance\n");
3197 fprintf (stderr, " print-pinning\n");
3198 fprintf (stderr, " heap-dump=<filename>\n");
3199 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3200 fprintf (stderr, " nursery-canaries\n");
3201 sgen_client_print_gc_debug_usage ();
3202 fprintf (stderr, "\n");
3204 usage_printed = TRUE;
3211 g_free (debug_opts);
3213 if (check_mark_bits_after_major_collection)
3214 nursery_clear_policy = CLEAR_AT_GC;
3216 if (major_collector.post_param_init)
3217 major_collector.post_param_init (&major_collector);
3219 if (major_collector.needs_thread_pool) {
3220 int num_workers = 1;
3221 if (major_collector.is_parallel) {
3222 /* FIXME Detect the number of physical cores, instead of logical */
3223 num_workers = mono_cpu_count () / 2;
3224 if (num_workers < 1)
3227 sgen_workers_init (num_workers);
3230 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3232 memset (&remset, 0, sizeof (remset));
3234 sgen_card_table_init (&remset);
3236 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");
3240 sgen_init_bridge ();
3244 sgen_gc_initialized ()
3246 return gc_initialized > 0;
3250 sgen_get_nursery_clear_policy (void)
3252 return nursery_clear_policy;
3258 mono_coop_mutex_lock (&gc_mutex);
3262 sgen_gc_unlock (void)
3264 mono_coop_mutex_unlock (&gc_mutex);
3268 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3270 major_collector.iterate_live_block_ranges (callback);
3274 sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback)
3276 major_collector.iterate_block_ranges (callback);
3280 sgen_get_major_collector (void)
3282 return &major_collector;
3286 sgen_get_remset (void)
3292 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3294 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3295 sgen_los_count_cards (los_total, los_marked);
3298 static gboolean world_is_stopped = FALSE;
3300 /* LOCKING: assumes the GC lock is held */
3302 sgen_stop_world (int generation)
3304 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3306 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3308 binary_protocol_world_stopping (generation, sgen_timestamp (), (gpointer) (gsize) mono_native_thread_id_get ());
3310 sgen_client_stop_world (generation);
3312 world_is_stopped = TRUE;
3314 if (binary_protocol_is_heavy_enabled ())
3315 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3316 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3319 /* LOCKING: assumes the GC lock is held */
3321 sgen_restart_world (int generation)
3323 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3326 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3328 if (binary_protocol_is_heavy_enabled ())
3329 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3330 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3332 world_is_stopped = FALSE;
3334 sgen_client_restart_world (generation, &stw_time);
3336 binary_protocol_world_restarted (generation, sgen_timestamp ());
3338 if (sgen_client_bridge_need_processing ())
3339 sgen_client_bridge_processing_finish (generation);
3341 sgen_memgov_collection_end (generation, stw_time);
3345 sgen_is_world_stopped (void)
3347 return world_is_stopped;
3351 sgen_check_whole_heap_stw (void)
3353 sgen_stop_world (0);
3354 sgen_clear_nursery_fragments ();
3355 sgen_check_whole_heap (TRUE);
3356 sgen_restart_world (0);
3360 sgen_timestamp (void)
3362 SGEN_TV_DECLARE (timestamp);
3363 SGEN_TV_GETTIME (timestamp);
3364 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3367 #endif /* HAVE_SGEN_GC */