2 * sgen-gc.c: Simple generational GC.
5 * Paolo Molaro (lupus@ximian.com)
6 * Rodrigo Kumpera (kumpera@gmail.com)
8 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
9 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
11 * Thread start/stop adapted from Boehm's GC:
12 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
13 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
14 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
15 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
16 * Copyright 2001-2003 Ximian, Inc
17 * Copyright 2003-2010 Novell, Inc.
18 * Copyright 2011 Xamarin, Inc.
19 * Copyright (C) 2012 Xamarin Inc
21 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
23 * Important: allocation provides always zeroed memory, having to do
24 * a memset after allocation is deadly for performance.
25 * Memory usage at startup is currently as follows:
27 * 64 KB internal space
29 * We should provide a small memory config with half the sizes
31 * We currently try to make as few mono assumptions as possible:
32 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
34 * 2) gc descriptor is the second word in the vtable (first word in the class)
35 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
36 * 4) there is a function to get an object's size and the number of
37 * elements in an array.
38 * 5) we know the special way bounds are allocated for complex arrays
39 * 6) we know about proxies and how to treat them when domains are unloaded
41 * Always try to keep stack usage to a minimum: no recursive behaviour
42 * and no large stack allocs.
44 * General description.
45 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
46 * When the nursery is full we start a nursery collection: this is performed with a
48 * When the old generation is full we start a copying GC of the old generation as well:
49 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
50 * in the future. Maybe we'll even do both during the same collection like IMMIX.
52 * The things that complicate this description are:
53 * *) pinned objects: we can't move them so we need to keep track of them
54 * *) no precise info of the thread stacks and registers: we need to be able to
55 * quickly find the objects that may be referenced conservatively and pin them
56 * (this makes the first issues more important)
57 * *) large objects are too expensive to be dealt with using copying GC: we handle them
58 * with mark/sweep during major collections
59 * *) some objects need to not move even if they are small (interned strings, Type handles):
60 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
61 * PinnedChunks regions
67 *) we could have a function pointer in MonoClass to implement
68 customized write barriers for value types
70 *) investigate the stuff needed to advance a thread to a GC-safe
71 point (single-stepping, read from unmapped memory etc) and implement it.
72 This would enable us to inline allocations and write barriers, for example,
73 or at least parts of them, like the write barrier checks.
74 We may need this also for handling precise info on stacks, even simple things
75 as having uninitialized data on the stack and having to wait for the prolog
76 to zero it. Not an issue for the last frame that we scan conservatively.
77 We could always not trust the value in the slots anyway.
79 *) modify the jit to save info about references in stack locations:
80 this can be done just for locals as a start, so that at least
81 part of the stack is handled precisely.
83 *) test/fix endianess issues
85 *) Implement a card table as the write barrier instead of remembered
86 sets? Card tables are not easy to implement with our current
87 memory layout. We have several different kinds of major heap
88 objects: Small objects in regular blocks, small objects in pinned
89 chunks and LOS objects. If we just have a pointer we have no way
90 to tell which kind of object it points into, therefore we cannot
91 know where its card table is. The least we have to do to make
92 this happen is to get rid of write barriers for indirect stores.
95 *) Get rid of write barriers for indirect stores. We can do this by
96 telling the GC to wbarrier-register an object once we do an ldloca
97 or ldelema on it, and to unregister it once it's not used anymore
98 (it can only travel downwards on the stack). The problem with
99 unregistering is that it needs to happen eventually no matter
100 what, even if exceptions are thrown, the thread aborts, etc.
101 Rodrigo suggested that we could do only the registering part and
102 let the collector find out (pessimistically) when it's safe to
103 unregister, namely when the stack pointer of the thread that
104 registered the object is higher than it was when the registering
105 happened. This might make for a good first implementation to get
106 some data on performance.
108 *) Some sort of blacklist support? Blacklists is a concept from the
109 Boehm GC: if during a conservative scan we find pointers to an
110 area which we might use as heap, we mark that area as unusable, so
111 pointer retention by random pinning pointers is reduced.
113 *) experiment with max small object size (very small right now - 2kb,
114 because it's tied to the max freelist size)
116 *) add an option to mmap the whole heap in one chunk: it makes for many
117 simplifications in the checks (put the nursery at the top and just use a single
118 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
119 not flexible (too much of the address space may be used by default or we can't
120 increase the heap as needed) and we'd need a race-free mechanism to return memory
121 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
122 was written to, munmap is needed, but the following mmap may not find the same segment
125 *) memzero the major fragments after restarting the world and optionally a smaller
128 *) investigate having fragment zeroing threads
130 *) separate locks for finalization and other minor stuff to reduce
133 *) try a different copying order to improve memory locality
135 *) a thread abort after a store but before the write barrier will
136 prevent the write barrier from executing
138 *) specialized dynamically generated markers/copiers
140 *) Dynamically adjust TLAB size to the number of threads. If we have
141 too many threads that do allocation, we might need smaller TLABs,
142 and we might get better performance with larger TLABs if we only
143 have a handful of threads. We could sum up the space left in all
144 assigned TLABs and if that's more than some percentage of the
145 nursery size, reduce the TLAB size.
147 *) Explore placing unreachable objects on unused nursery memory.
148 Instead of memset'ng a region to zero, place an int[] covering it.
149 A good place to start is add_nursery_frag. The tricky thing here is
150 placing those objects atomically outside of a collection.
152 *) Allocation should use asymmetric Dekker synchronization:
153 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
154 This should help weak consistency archs.
161 #define _XOPEN_SOURCE
162 #define _DARWIN_C_SOURCE
168 #ifdef HAVE_PTHREAD_H
171 #ifdef HAVE_PTHREAD_NP_H
172 #include <pthread_np.h>
180 #include "mono/sgen/sgen-gc.h"
181 #include "mono/sgen/sgen-cardtable.h"
182 #include "mono/sgen/sgen-protocol.h"
183 #include "mono/sgen/sgen-memory-governor.h"
184 #include "mono/sgen/sgen-hash-table.h"
185 #include "mono/sgen/sgen-cardtable.h"
186 #include "mono/sgen/sgen-pinning.h"
187 #include "mono/sgen/sgen-workers.h"
188 #include "mono/sgen/sgen-client.h"
189 #include "mono/sgen/sgen-pointer-queue.h"
190 #include "mono/sgen/gc-internal-agnostic.h"
191 #include "mono/utils/mono-proclib.h"
192 #include "mono/utils/mono-memory-model.h"
193 #include "mono/utils/hazard-pointer.h"
195 #include <mono/utils/memcheck.h>
197 #undef pthread_create
199 #undef pthread_detach
202 * ######################################################################
203 * ######## Types and constants used by the GC.
204 * ######################################################################
207 /* 0 means not initialized, 1 is initialized, -1 means in progress */
208 static int gc_initialized = 0;
209 /* If set, check if we need to do something every X allocations */
210 gboolean has_per_allocation_action;
211 /* If set, do a heap check every X allocation */
212 guint32 verify_before_allocs = 0;
213 /* If set, do a minor collection before every X allocation */
214 guint32 collect_before_allocs = 0;
215 /* If set, do a whole heap check before each collection */
216 static gboolean whole_heap_check_before_collection = FALSE;
217 /* If set, do a remset consistency check at various opportunities */
218 static gboolean remset_consistency_checks = FALSE;
219 /* If set, do a mod union consistency check before each finishing collection pause */
220 static gboolean mod_union_consistency_check = FALSE;
221 /* If set, check whether mark bits are consistent after major collections */
222 static gboolean check_mark_bits_after_major_collection = FALSE;
223 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
224 static gboolean check_nursery_objects_pinned = FALSE;
225 /* If set, do a few checks when the concurrent collector is used */
226 static gboolean do_concurrent_checks = FALSE;
227 /* If set, do a plausibility check on the scan_starts before and after
229 static gboolean do_scan_starts_check = FALSE;
231 static gboolean disable_minor_collections = FALSE;
232 static gboolean disable_major_collections = FALSE;
233 static gboolean do_verify_nursery = FALSE;
234 static gboolean do_dump_nursery_content = FALSE;
235 static gboolean enable_nursery_canaries = FALSE;
237 static gboolean precleaning_enabled = TRUE;
239 #ifdef HEAVY_STATISTICS
240 guint64 stat_objects_alloced_degraded = 0;
241 guint64 stat_bytes_alloced_degraded = 0;
243 guint64 stat_copy_object_called_nursery = 0;
244 guint64 stat_objects_copied_nursery = 0;
245 guint64 stat_copy_object_called_major = 0;
246 guint64 stat_objects_copied_major = 0;
248 guint64 stat_scan_object_called_nursery = 0;
249 guint64 stat_scan_object_called_major = 0;
251 guint64 stat_slots_allocated_in_vain;
253 guint64 stat_nursery_copy_object_failed_from_space = 0;
254 guint64 stat_nursery_copy_object_failed_forwarded = 0;
255 guint64 stat_nursery_copy_object_failed_pinned = 0;
256 guint64 stat_nursery_copy_object_failed_to_space = 0;
258 static guint64 stat_wbarrier_add_to_global_remset = 0;
259 static guint64 stat_wbarrier_arrayref_copy = 0;
260 static guint64 stat_wbarrier_generic_store = 0;
261 static guint64 stat_wbarrier_generic_store_atomic = 0;
262 static guint64 stat_wbarrier_set_root = 0;
265 static guint64 stat_pinned_objects = 0;
267 static guint64 time_minor_pre_collection_fragment_clear = 0;
268 static guint64 time_minor_pinning = 0;
269 static guint64 time_minor_scan_remsets = 0;
270 static guint64 time_minor_scan_pinned = 0;
271 static guint64 time_minor_scan_roots = 0;
272 static guint64 time_minor_finish_gray_stack = 0;
273 static guint64 time_minor_fragment_creation = 0;
275 static guint64 time_major_pre_collection_fragment_clear = 0;
276 static guint64 time_major_pinning = 0;
277 static guint64 time_major_scan_pinned = 0;
278 static guint64 time_major_scan_roots = 0;
279 static guint64 time_major_scan_mod_union = 0;
280 static guint64 time_major_finish_gray_stack = 0;
281 static guint64 time_major_free_bigobjs = 0;
282 static guint64 time_major_los_sweep = 0;
283 static guint64 time_major_sweep = 0;
284 static guint64 time_major_fragment_creation = 0;
286 static guint64 time_max = 0;
288 static SGEN_TV_DECLARE (time_major_conc_collection_start);
289 static SGEN_TV_DECLARE (time_major_conc_collection_end);
291 int gc_debug_level = 0;
293 static char* gc_params_options;
294 static char* gc_debug_options;
298 mono_gc_flush_info (void)
300 fflush (gc_debug_file);
304 #define TV_DECLARE SGEN_TV_DECLARE
305 #define TV_GETTIME SGEN_TV_GETTIME
306 #define TV_ELAPSED SGEN_TV_ELAPSED
308 static SGEN_TV_DECLARE (sgen_init_timestamp);
310 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
312 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
313 #define object_is_pinned SGEN_OBJECT_IS_PINNED
314 #define pin_object SGEN_PIN_OBJECT
316 #define ptr_in_nursery sgen_ptr_in_nursery
318 #define LOAD_VTABLE SGEN_LOAD_VTABLE
321 nursery_canaries_enabled (void)
323 return enable_nursery_canaries;
326 #define safe_object_get_size sgen_safe_object_get_size
328 #if defined(HAVE_CONC_GC_AS_DEFAULT)
329 /* Use concurrent major on deskstop platforms */
330 #define DEFAULT_MAJOR_INIT sgen_marksweep_conc_init
331 #define DEFAULT_MAJOR_NAME "marksweep-conc"
333 #define DEFAULT_MAJOR_INIT sgen_marksweep_init
334 #define DEFAULT_MAJOR_NAME "marksweep"
338 * ######################################################################
339 * ######## Global data.
340 * ######################################################################
342 MonoCoopMutex gc_mutex;
344 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
346 size_t degraded_mode = 0;
348 static mword bytes_pinned_from_failed_allocation = 0;
350 GCMemSection *nursery_section = NULL;
351 static volatile mword lowest_heap_address = ~(mword)0;
352 static volatile mword highest_heap_address = 0;
354 MonoCoopMutex sgen_interruption_mutex;
356 int current_collection_generation = -1;
357 static volatile gboolean concurrent_collection_in_progress = FALSE;
359 /* objects that are ready to be finalized */
360 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
361 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
363 /* registered roots: the key to the hash is the root start address */
365 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
367 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
368 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
369 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
370 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
372 static mword roots_size = 0; /* amount of memory in the root set */
374 /* The size of a TLAB */
375 /* The bigger the value, the less often we have to go to the slow path to allocate a new
376 * one, but the more space is wasted by threads not allocating much memory.
378 * FIXME: Make this self-tuning for each thread.
380 guint32 tlab_size = (1024 * 4);
382 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
384 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
386 #define ALIGN_UP SGEN_ALIGN_UP
388 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
389 MonoNativeThreadId main_gc_thread = NULL;
392 /*Object was pinned during the current collection*/
393 static mword objects_pinned;
396 * ######################################################################
397 * ######## Macros and function declarations.
398 * ######################################################################
401 /* forward declarations */
402 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
404 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
405 static void finish_gray_stack (int generation, ScanCopyContext ctx);
408 SgenMajorCollector major_collector;
409 SgenMinorCollector sgen_minor_collector;
411 static SgenRememberedSet remset;
414 * The gray queue a worker job must use. If we're not parallel or
415 * concurrent, we use the main gray queue.
417 static SgenGrayQueue*
418 sgen_workers_get_job_gray_queue (WorkerData *worker_data, SgenGrayQueue *default_gray_queue)
421 return &worker_data->private_gray_queue;
422 SGEN_ASSERT (0, default_gray_queue, "Why don't we have a default gray queue when we're not running in a worker thread?");
423 return default_gray_queue;
427 gray_queue_redirect (SgenGrayQueue *queue)
429 SGEN_ASSERT (0, concurrent_collection_in_progress, "Where are we redirecting the gray queue to, without a concurrent collection?");
431 sgen_workers_take_from_queue (queue);
435 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries)
437 while (start < end) {
441 if (!*(void**)start) {
442 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
447 if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
453 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
454 CHECK_CANARY_FOR_OBJECT ((GCObject*)obj, fail_on_canaries);
455 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
456 callback ((GCObject*)obj, size, data);
457 CANARIFY_SIZE (size);
459 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
467 * sgen_add_to_global_remset:
469 * The global remset contains locations which point into newspace after
470 * a minor collection. This can happen if the objects they point to are pinned.
472 * LOCKING: If called from a parallel collector, the global remset
473 * lock must be held. For serial collectors that is not necessary.
476 sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
478 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
480 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
482 if (!major_collector.is_concurrent) {
483 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
485 if (current_collection_generation == -1)
486 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
489 if (!object_is_pinned (obj))
490 SGEN_ASSERT (5, sgen_minor_collector.is_split || sgen_concurrent_collection_in_progress (), "Non-pinned objects can only remain in nursery if it is a split nursery");
491 else if (sgen_cement_lookup_or_register (obj))
494 remset.record_pointer (ptr);
496 sgen_pin_stats_register_global_remset (obj);
498 SGEN_LOG (8, "Adding global remset for %p", ptr);
499 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
503 * sgen_drain_gray_stack:
505 * Scan objects in the gray stack until the stack is empty. This should be called
506 * frequently after each object is copied, to achieve better locality and cache
511 sgen_drain_gray_stack (ScanCopyContext ctx)
513 SGEN_ASSERT (0, ctx.ops->drain_gray_stack, "Why do we have a scan/copy context with a missing drain gray stack function?");
515 return ctx.ops->drain_gray_stack (ctx.queue);
519 * Addresses in the pin queue are already sorted. This function finds
520 * the object header for each address and pins the object. The
521 * addresses must be inside the nursery section. The (start of the)
522 * address array is overwritten with the addresses of the actually
523 * pinned objects. Return the number of pinned objects.
526 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
528 GCMemSection *section = nursery_section;
529 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
530 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
531 void *start_nursery = section->data;
532 void *end_nursery = section->next_data;
537 void *pinning_front = start_nursery;
539 void **definitely_pinned = start;
540 ScanObjectFunc scan_func = ctx.ops->scan_object;
541 SgenGrayQueue *queue = ctx.queue;
543 sgen_nursery_allocator_prepare_for_pinning ();
545 while (start < end) {
546 GCObject *obj_to_pin = NULL;
547 size_t obj_to_pin_size = 0;
552 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
553 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
560 SGEN_LOG (5, "Considering pinning addr %p", addr);
561 /* We've already processed everything up to pinning_front. */
562 if (addr < pinning_front) {
568 * Find the closest scan start <= addr. We might search backward in the
569 * scan_starts array because entries might be NULL. In the worst case we
570 * start at start_nursery.
572 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
573 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
574 search_start = (void*)section->scan_starts [idx];
575 if (!search_start || search_start > addr) {
578 search_start = section->scan_starts [idx];
579 if (search_start && search_start <= addr)
582 if (!search_start || search_start > addr)
583 search_start = start_nursery;
587 * If the pinning front is closer than the scan start we found, start
588 * searching at the front.
590 if (search_start < pinning_front)
591 search_start = pinning_front;
594 * Now addr should be in an object a short distance from search_start.
596 * search_start must point to zeroed mem or point to an object.
599 size_t obj_size, canarified_obj_size;
602 if (!*(void**)search_start) {
603 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
604 /* The loop condition makes sure we don't overrun addr. */
608 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
611 * Filler arrays are marked by an invalid sync word. We don't
612 * consider them for pinning. They are not delimited by canaries,
615 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
616 CHECK_CANARY_FOR_OBJECT (search_start, TRUE);
617 CANARIFY_SIZE (canarified_obj_size);
619 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
620 /* This is the object we're looking for. */
621 obj_to_pin = (GCObject*)search_start;
622 obj_to_pin_size = canarified_obj_size;
627 /* Skip to the next object */
628 search_start = (void*)((char*)search_start + canarified_obj_size);
629 } while (search_start <= addr);
631 /* We've searched past the address we were looking for. */
633 pinning_front = search_start;
634 goto next_pin_queue_entry;
638 * We've found an object to pin. It might still be a dummy array, but we
639 * can advance the pinning front in any case.
641 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
644 * If this is a dummy array marking the beginning of a nursery
645 * fragment, we don't pin it.
647 if (sgen_client_object_is_array_fill (obj_to_pin))
648 goto next_pin_queue_entry;
651 * Finally - pin the object!
653 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
654 if (do_scan_objects) {
655 scan_func (obj_to_pin, desc, queue);
657 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
658 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
659 binary_protocol_pin (obj_to_pin,
660 (gpointer)LOAD_VTABLE (obj_to_pin),
661 safe_object_get_size (obj_to_pin));
663 pin_object (obj_to_pin);
664 GRAY_OBJECT_ENQUEUE_SERIAL (queue, obj_to_pin, desc);
665 sgen_pin_stats_register_object (obj_to_pin, GENERATION_NURSERY);
666 definitely_pinned [count] = obj_to_pin;
669 if (concurrent_collection_in_progress)
670 sgen_pinning_register_pinned_in_nursery (obj_to_pin);
672 next_pin_queue_entry:
676 sgen_client_nursery_objects_pinned (definitely_pinned, count);
677 stat_pinned_objects += count;
682 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
686 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
689 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
690 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
694 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
695 * when we can't promote an object because we're out of memory.
698 sgen_pin_object (GCObject *object, SgenGrayQueue *queue)
700 SGEN_ASSERT (0, sgen_ptr_in_nursery (object), "We're only supposed to use this for pinning nursery objects when out of memory.");
703 * All pinned objects are assumed to have been staged, so we need to stage as well.
704 * Also, the count of staged objects shows that "late pinning" happened.
706 sgen_pin_stage_ptr (object);
708 SGEN_PIN_OBJECT (object);
709 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
712 sgen_pin_stats_register_object (object, GENERATION_NURSERY);
714 GRAY_OBJECT_ENQUEUE_SERIAL (queue, object, sgen_obj_get_descriptor_safe (object));
717 /* Sort the addresses in array in increasing order.
718 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
721 sgen_sort_addresses (void **array, size_t size)
726 for (i = 1; i < size; ++i) {
729 size_t parent = (child - 1) / 2;
731 if (array [parent] >= array [child])
734 tmp = array [parent];
735 array [parent] = array [child];
742 for (i = size - 1; i > 0; --i) {
745 array [i] = array [0];
751 while (root * 2 + 1 <= end) {
752 size_t child = root * 2 + 1;
754 if (child < end && array [child] < array [child + 1])
756 if (array [root] >= array [child])
760 array [root] = array [child];
769 * Scan the memory between start and end and queue values which could be pointers
770 * to the area between start_nursery and end_nursery for later consideration.
771 * Typically used for thread stacks.
774 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
778 SGEN_ASSERT (0, ((mword)start & (SIZEOF_VOID_P - 1)) == 0, "Why are we scanning for references in unaligned memory ?");
780 #if defined(VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE) && !defined(_WIN64)
781 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
784 while (start < end) {
786 * *start can point to the middle of an object
787 * note: should we handle pointing at the end of an object?
788 * pinning in C# code disallows pointing at the end of an object
789 * but there is some small chance that an optimizing C compiler
790 * may keep the only reference to an object by pointing
791 * at the end of it. We ignore this small chance for now.
792 * Pointers to the end of an object are indistinguishable
793 * from pointers to the start of the next object in memory
794 * so if we allow that we'd need to pin two objects...
795 * We queue the pointer in an array, the
796 * array will then be sorted and uniqued. This way
797 * we can coalesce several pinning pointers and it should
798 * be faster since we'd do a memory scan with increasing
799 * addresses. Note: we can align the address to the allocation
800 * alignment, so the unique process is more effective.
802 mword addr = (mword)*start;
803 addr &= ~(ALLOC_ALIGN - 1);
804 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
805 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
806 sgen_pin_stage_ptr ((void*)addr);
807 binary_protocol_pin_stage (start, (void*)addr);
808 sgen_pin_stats_register_address ((char*)addr, pin_type);
814 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
818 * The first thing we do in a collection is to identify pinned objects.
819 * This function considers all the areas of memory that need to be
820 * conservatively scanned.
823 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
827 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);
828 /* objects pinned from the API are inside these roots */
829 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
830 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
831 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
832 } SGEN_HASH_TABLE_FOREACH_END;
833 /* now deal with the thread stacks
834 * in the future we should be able to conservatively scan only:
835 * *) the cpu registers
836 * *) the unmanaged stack frames
837 * *) the _last_ managed stack frame
838 * *) pointers slots in managed frames
840 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
844 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
846 ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
847 ctx->ops->copy_or_mark_object (obj, ctx->queue);
851 * The memory area from start_root to end_root contains pointers to objects.
852 * Their position is precisely described by @desc (this means that the pointer
853 * can be either NULL or the pointer to the start of an object).
854 * This functions copies them to to_space updates them.
856 * This function is not thread-safe!
859 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, SgenDescriptor desc, ScanCopyContext ctx)
861 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
862 SgenGrayQueue *queue = ctx.queue;
864 switch (desc & ROOT_DESC_TYPE_MASK) {
865 case ROOT_DESC_BITMAP:
866 desc >>= ROOT_DESC_TYPE_SHIFT;
868 if ((desc & 1) && *start_root) {
869 copy_func ((GCObject**)start_root, queue);
870 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
876 case ROOT_DESC_COMPLEX: {
877 gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
878 gsize bwords = (*bitmap_data) - 1;
879 void **start_run = start_root;
881 while (bwords-- > 0) {
882 gsize bmap = *bitmap_data++;
883 void **objptr = start_run;
885 if ((bmap & 1) && *objptr) {
886 copy_func ((GCObject**)objptr, queue);
887 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
892 start_run += GC_BITS_PER_WORD;
896 case ROOT_DESC_USER: {
897 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
898 marker (start_root, single_arg_user_copy_or_mark, &ctx);
901 case ROOT_DESC_RUN_LEN:
902 g_assert_not_reached ();
904 g_assert_not_reached ();
909 reset_heap_boundaries (void)
911 lowest_heap_address = ~(mword)0;
912 highest_heap_address = 0;
916 sgen_update_heap_boundaries (mword low, mword high)
921 old = lowest_heap_address;
924 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
927 old = highest_heap_address;
930 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
934 * Allocate and setup the data structures needed to be able to allocate objects
935 * in the nursery. The nursery is stored in nursery_section.
940 GCMemSection *section;
947 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
948 /* later we will alloc a larger area for the nursery but only activate
949 * what we need. The rest will be used as expansion if we have too many pinned
950 * objects in the existing nursery.
952 /* FIXME: handle OOM */
953 section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
955 alloc_size = sgen_nursery_size;
957 /* If there isn't enough space even for the nursery we should simply abort. */
958 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
960 data = (char *)major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
961 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
962 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 ());
963 section->data = section->next_data = data;
964 section->size = alloc_size;
965 section->end_data = data + sgen_nursery_size;
966 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
967 section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
968 section->num_scan_start = scan_starts;
970 nursery_section = section;
972 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
976 mono_gc_get_logfile (void)
978 return gc_debug_file;
982 mono_gc_params_set (const char* options)
984 if (gc_params_options)
985 g_free (gc_params_options);
987 gc_params_options = g_strdup (options);
991 mono_gc_debug_set (const char* options)
993 if (gc_debug_options)
994 g_free (gc_debug_options);
996 gc_debug_options = g_strdup (options);
1000 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1002 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1003 SgenGrayQueue *queue = ctx.queue;
1006 for (i = 0; i < fin_queue->next_slot; ++i) {
1007 GCObject *obj = (GCObject *)fin_queue->data [i];
1010 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1011 copy_func ((GCObject**)&fin_queue->data [i], queue);
1016 generation_name (int generation)
1018 switch (generation) {
1019 case GENERATION_NURSERY: return "nursery";
1020 case GENERATION_OLD: return "old";
1021 default: g_assert_not_reached ();
1026 sgen_generation_name (int generation)
1028 return generation_name (generation);
1032 finish_gray_stack (int generation, ScanCopyContext ctx)
1036 int done_with_ephemerons, ephemeron_rounds = 0;
1037 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1038 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1039 SgenGrayQueue *queue = ctx.queue;
1041 binary_protocol_finish_gray_stack_start (sgen_timestamp (), generation);
1043 * We copied all the reachable objects. Now it's the time to copy
1044 * the objects that were not referenced by the roots, but by the copied objects.
1045 * we built a stack of objects pointed to by gray_start: they are
1046 * additional roots and we may add more items as we go.
1047 * We loop until gray_start == gray_objects which means no more objects have
1048 * been added. Note this is iterative: no recursion is involved.
1049 * We need to walk the LO list as well in search of marked big objects
1050 * (use a flag since this is needed only on major collections). We need to loop
1051 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1052 * To achieve better cache locality and cache usage, we drain the gray stack
1053 * frequently, after each object is copied, and just finish the work here.
1055 sgen_drain_gray_stack (ctx);
1057 SGEN_LOG (2, "%s generation done", generation_name (generation));
1060 Reset bridge data, we might have lingering data from a previous collection if this is a major
1061 collection trigged by minor overflow.
1063 We must reset the gathered bridges since their original block might be evacuated due to major
1064 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1066 if (sgen_client_bridge_need_processing ())
1067 sgen_client_bridge_reset_data ();
1070 * Mark all strong toggleref objects. This must be done before we walk ephemerons or finalizers
1071 * to ensure they see the full set of live objects.
1073 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1076 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1077 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1078 * objects that are in fact reachable.
1080 done_with_ephemerons = 0;
1082 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1083 sgen_drain_gray_stack (ctx);
1085 } while (!done_with_ephemerons);
1087 if (sgen_client_bridge_need_processing ()) {
1088 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1089 sgen_drain_gray_stack (ctx);
1090 sgen_collect_bridge_objects (generation, ctx);
1091 if (generation == GENERATION_OLD)
1092 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1095 Do the first bridge step here, as the collector liveness state will become useless after that.
1097 An important optimization is to only proccess the possibly dead part of the object graph and skip
1098 over all live objects as we transitively know everything they point must be alive too.
1100 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1102 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1103 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1106 sgen_client_bridge_processing_stw_step ();
1110 Make sure we drain the gray stack before processing disappearing links and finalizers.
1111 If we don't make sure it is empty we might wrongly see a live object as dead.
1113 sgen_drain_gray_stack (ctx);
1116 We must clear weak links that don't track resurrection before processing object ready for
1117 finalization so they can be cleared before that.
1119 sgen_null_link_in_range (generation, ctx, FALSE);
1120 if (generation == GENERATION_OLD)
1121 sgen_null_link_in_range (GENERATION_NURSERY, ctx, FALSE);
1124 /* walk the finalization queue and move also the objects that need to be
1125 * finalized: use the finalized objects as new roots so the objects they depend
1126 * on are also not reclaimed. As with the roots above, only objects in the nursery
1127 * are marked/copied.
1129 sgen_finalize_in_range (generation, ctx);
1130 if (generation == GENERATION_OLD)
1131 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1132 /* drain the new stack that might have been created */
1133 SGEN_LOG (6, "Precise scan of gray area post fin");
1134 sgen_drain_gray_stack (ctx);
1137 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1139 done_with_ephemerons = 0;
1141 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1142 sgen_drain_gray_stack (ctx);
1144 } while (!done_with_ephemerons);
1146 sgen_client_clear_unreachable_ephemerons (ctx);
1149 * We clear togglerefs only after all possible chances of revival are done.
1150 * This is semantically more inline with what users expect and it allows for
1151 * user finalizers to correctly interact with TR objects.
1153 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1156 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);
1159 * handle disappearing links
1160 * Note we do this after checking the finalization queue because if an object
1161 * survives (at least long enough to be finalized) we don't clear the link.
1162 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1163 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1166 g_assert (sgen_gray_object_queue_is_empty (queue));
1168 sgen_null_link_in_range (generation, ctx, TRUE);
1169 if (generation == GENERATION_OLD)
1170 sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
1171 if (sgen_gray_object_queue_is_empty (queue))
1173 sgen_drain_gray_stack (ctx);
1176 g_assert (sgen_gray_object_queue_is_empty (queue));
1178 binary_protocol_finish_gray_stack_end (sgen_timestamp (), generation);
1182 sgen_check_section_scan_starts (GCMemSection *section)
1185 for (i = 0; i < section->num_scan_start; ++i) {
1186 if (section->scan_starts [i]) {
1187 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1188 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1194 check_scan_starts (void)
1196 if (!do_scan_starts_check)
1198 sgen_check_section_scan_starts (nursery_section);
1199 major_collector.check_scan_starts ();
1203 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1207 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
1208 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1209 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1210 } SGEN_HASH_TABLE_FOREACH_END;
1216 static gboolean inited = FALSE;
1221 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1223 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1224 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1225 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1226 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1227 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1228 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1230 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1231 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1232 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1233 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1234 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1235 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1236 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1237 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1238 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1239 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1241 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1243 #ifdef HEAVY_STATISTICS
1244 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1245 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1246 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1247 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1248 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1250 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1251 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1253 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1254 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1255 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1256 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1258 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1259 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1261 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1263 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1264 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1265 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1266 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1268 sgen_nursery_allocator_init_heavy_stats ();
1276 reset_pinned_from_failed_allocation (void)
1278 bytes_pinned_from_failed_allocation = 0;
1282 sgen_set_pinned_from_failed_allocation (mword objsize)
1284 bytes_pinned_from_failed_allocation += objsize;
1288 sgen_collection_is_concurrent (void)
1290 switch (current_collection_generation) {
1291 case GENERATION_NURSERY:
1293 case GENERATION_OLD:
1294 return concurrent_collection_in_progress;
1296 g_error ("Invalid current generation %d", current_collection_generation);
1302 sgen_concurrent_collection_in_progress (void)
1304 return concurrent_collection_in_progress;
1308 SgenThreadPoolJob job;
1309 SgenObjectOperations *ops;
1310 SgenGrayQueue *gc_thread_gray_queue;
1318 static ScanCopyContext
1319 scan_copy_context_for_scan_job (void *worker_data_untyped, ScanJob *job)
1321 WorkerData *worker_data = (WorkerData *)worker_data_untyped;
1323 return CONTEXT_FROM_OBJECT_OPERATIONS (job->ops, sgen_workers_get_job_gray_queue (worker_data, job->gc_thread_gray_queue));
1327 job_remembered_set_scan (void *worker_data_untyped, SgenThreadPoolJob *job)
1329 remset.scan_remsets (scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job));
1337 } ScanFromRegisteredRootsJob;
1340 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1342 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1343 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1345 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1352 } ScanThreadDataJob;
1355 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1357 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1358 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1360 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1365 SgenPointerQueue *queue;
1366 } ScanFinalizerEntriesJob;
1369 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1371 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1372 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1374 scan_finalizer_entries (job_data->queue, ctx);
1378 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1380 ParallelScanJob *job_data = (ParallelScanJob*)job;
1381 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1383 g_assert (concurrent_collection_in_progress);
1384 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1388 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1390 ParallelScanJob *job_data = (ParallelScanJob*)job;
1391 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1393 g_assert (concurrent_collection_in_progress);
1394 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1398 job_major_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1400 ParallelScanJob *job_data = (ParallelScanJob*)job;
1401 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1403 g_assert (concurrent_collection_in_progress);
1405 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1409 job_los_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1411 ParallelScanJob *job_data = (ParallelScanJob*)job;
1412 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1414 g_assert (concurrent_collection_in_progress);
1416 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1420 job_scan_last_pinned (void *worker_data_untyped, SgenThreadPoolJob *job)
1422 ScanJob *job_data = (ScanJob*)job;
1423 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1425 g_assert (concurrent_collection_in_progress);
1427 sgen_scan_pin_queue_objects (ctx);
1431 workers_finish_callback (void)
1433 ParallelScanJob *psj;
1435 int split_count = sgen_workers_get_job_split_count ();
1437 /* Mod union preclean jobs */
1438 for (i = 0; i < split_count; i++) {
1439 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean major mod union cardtable", job_major_mod_union_preclean, sizeof (ParallelScanJob));
1440 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1441 psj->scan_job.gc_thread_gray_queue = NULL;
1443 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1446 for (i = 0; i < split_count; i++) {
1447 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean los mod union cardtable", job_los_mod_union_preclean, sizeof (ParallelScanJob));
1448 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1449 psj->scan_job.gc_thread_gray_queue = NULL;
1451 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1454 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan last pinned", job_scan_last_pinned, sizeof (ScanJob));
1455 sj->ops = sgen_workers_get_idle_func_object_ops ();
1456 sj->gc_thread_gray_queue = NULL;
1457 sgen_workers_enqueue_job (&sj->job, TRUE);
1461 init_gray_queue (SgenGrayQueue *gc_thread_gray_queue, gboolean use_workers)
1464 sgen_workers_init_distribute_gray_queue ();
1465 sgen_gray_object_queue_init (gc_thread_gray_queue, NULL, TRUE);
1469 enqueue_scan_from_roots_jobs (SgenGrayQueue *gc_thread_gray_queue, char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
1471 ScanFromRegisteredRootsJob *scrrj;
1472 ScanThreadDataJob *stdj;
1473 ScanFinalizerEntriesJob *sfej;
1475 /* registered roots, this includes static fields */
1477 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1478 scrrj->scan_job.ops = ops;
1479 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1480 scrrj->heap_start = heap_start;
1481 scrrj->heap_end = heap_end;
1482 scrrj->root_type = ROOT_TYPE_NORMAL;
1483 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1485 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1486 scrrj->scan_job.ops = ops;
1487 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1488 scrrj->heap_start = heap_start;
1489 scrrj->heap_end = heap_end;
1490 scrrj->root_type = ROOT_TYPE_WBARRIER;
1491 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1495 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1496 stdj->scan_job.ops = ops;
1497 stdj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1498 stdj->heap_start = heap_start;
1499 stdj->heap_end = heap_end;
1500 sgen_workers_enqueue_job (&stdj->scan_job.job, enqueue);
1502 /* Scan the list of objects ready for finalization. */
1504 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1505 sfej->scan_job.ops = ops;
1506 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1507 sfej->queue = &fin_ready_queue;
1508 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1510 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1511 sfej->scan_job.ops = ops;
1512 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1513 sfej->queue = &critical_fin_queue;
1514 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1518 * Perform a nursery collection.
1520 * Return whether any objects were late-pinned due to being out of memory.
1523 collect_nursery (const char *reason, gboolean is_overflow, SgenGrayQueue *unpin_queue)
1525 gboolean needs_major;
1526 size_t max_garbage_amount;
1528 mword fragment_total;
1530 SgenGrayQueue gc_thread_gray_queue;
1531 SgenObjectOperations *object_ops;
1532 ScanCopyContext ctx;
1535 SGEN_TV_DECLARE (last_minor_collection_start_tv);
1536 SGEN_TV_DECLARE (last_minor_collection_end_tv);
1538 if (disable_minor_collections)
1541 TV_GETTIME (last_minor_collection_start_tv);
1542 atv = last_minor_collection_start_tv;
1544 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1546 if (sgen_concurrent_collection_in_progress ())
1547 object_ops = &sgen_minor_collector.serial_ops_with_concurrent_major;
1549 object_ops = &sgen_minor_collector.serial_ops;
1551 if (do_verify_nursery || do_dump_nursery_content)
1552 sgen_debug_verify_nursery (do_dump_nursery_content);
1554 current_collection_generation = GENERATION_NURSERY;
1556 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1558 reset_pinned_from_failed_allocation ();
1560 check_scan_starts ();
1562 sgen_nursery_alloc_prepare_for_minor ();
1566 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
1567 /* FIXME: optimize later to use the higher address where an object can be present */
1568 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
1570 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 ()));
1571 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
1572 g_assert (nursery_section->size >= max_garbage_amount);
1574 /* world must be stopped already */
1576 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1578 sgen_client_pre_collection_checks ();
1580 nursery_section->next_data = nursery_next;
1582 major_collector.start_nursery_collection ();
1584 sgen_memgov_minor_collection_start ();
1586 init_gray_queue (&gc_thread_gray_queue, FALSE);
1587 ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops, &gc_thread_gray_queue);
1589 gc_stats.minor_gc_count ++;
1591 sgen_process_fin_stage_entries ();
1593 /* pin from pinned handles */
1594 sgen_init_pinning ();
1595 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1596 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
1597 /* pin cemented objects */
1598 sgen_pin_cemented_objects ();
1599 /* identify pinned objects */
1600 sgen_optimize_pin_queue ();
1601 sgen_pinning_setup_section (nursery_section);
1603 pin_objects_in_nursery (FALSE, ctx);
1604 sgen_pinning_trim_queue_to_section (nursery_section);
1606 if (remset_consistency_checks)
1607 sgen_check_remset_consistency ();
1609 if (whole_heap_check_before_collection) {
1610 sgen_clear_nursery_fragments ();
1611 sgen_check_whole_heap (FALSE);
1615 time_minor_pinning += TV_ELAPSED (btv, atv);
1616 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (btv, atv));
1617 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1619 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan remset", job_remembered_set_scan, sizeof (ScanJob));
1620 sj->ops = object_ops;
1621 sj->gc_thread_gray_queue = &gc_thread_gray_queue;
1622 sgen_workers_enqueue_job (&sj->job, FALSE);
1624 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1626 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1627 SGEN_LOG (2, "Old generation scan: %lld usecs", (long long)TV_ELAPSED (atv, btv));
1629 sgen_pin_stats_report ();
1631 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1632 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1635 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1637 enqueue_scan_from_roots_jobs (&gc_thread_gray_queue, sgen_get_nursery_start (), nursery_next, object_ops, FALSE);
1640 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1642 finish_gray_stack (GENERATION_NURSERY, ctx);
1645 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1646 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1648 if (objects_pinned) {
1649 sgen_optimize_pin_queue ();
1650 sgen_pinning_setup_section (nursery_section);
1654 * This is the latest point at which we can do this check, because
1655 * sgen_build_nursery_fragments() unpins nursery objects again.
1657 if (remset_consistency_checks)
1658 sgen_check_remset_consistency ();
1660 /* walk the pin_queue, build up the fragment list of free memory, unmark
1661 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1664 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1665 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1666 if (!fragment_total)
1669 /* Clear TLABs for all threads */
1670 sgen_clear_tlabs ();
1672 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1674 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1675 SGEN_LOG (2, "Fragment creation: %lld usecs, %lu bytes available", (long long)TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1677 if (remset_consistency_checks)
1678 sgen_check_major_refs ();
1680 major_collector.finish_nursery_collection ();
1682 TV_GETTIME (last_minor_collection_end_tv);
1683 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1685 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1687 /* prepare the pin queue for the next collection */
1688 sgen_finish_pinning ();
1689 if (sgen_have_pending_finalizers ()) {
1690 SGEN_LOG (4, "Finalizer-thread wakeup");
1691 sgen_client_finalize_notify ();
1693 sgen_pin_stats_reset ();
1694 /* clear cemented hash */
1695 sgen_cement_clear_below_threshold ();
1697 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
1699 remset.finish_minor_collection ();
1701 check_scan_starts ();
1703 binary_protocol_flush_buffers (FALSE);
1705 sgen_memgov_minor_collection_end (reason, is_overflow);
1707 /*objects are late pinned because of lack of memory, so a major is a good call*/
1708 needs_major = objects_pinned > 0;
1709 current_collection_generation = -1;
1712 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1714 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1715 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1721 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1722 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1723 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1724 } CopyOrMarkFromRootsMode;
1727 major_copy_or_mark_from_roots (SgenGrayQueue *gc_thread_gray_queue, size_t *old_next_pin_slot, CopyOrMarkFromRootsMode mode, SgenObjectOperations *object_ops_nopar, SgenObjectOperations *object_ops_par)
1732 /* FIXME: only use these values for the precise scan
1733 * note that to_space pointers should be excluded anyway...
1735 char *heap_start = NULL;
1736 char *heap_end = (char*)-1;
1737 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue);
1738 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1740 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1742 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1743 /*This cleans up unused fragments */
1744 sgen_nursery_allocator_prepare_for_pinning ();
1746 if (do_concurrent_checks)
1747 sgen_debug_check_nursery_is_clean ();
1749 /* The concurrent collector doesn't touch the nursery. */
1750 sgen_nursery_alloc_prepare_for_major ();
1755 /* Pinning depends on this */
1756 sgen_clear_nursery_fragments ();
1758 if (whole_heap_check_before_collection)
1759 sgen_check_whole_heap (TRUE);
1762 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1764 if (!sgen_collection_is_concurrent ())
1765 nursery_section->next_data = sgen_get_nursery_end ();
1766 /* we should also coalesce scanning from sections close to each other
1767 * and deal with pointers outside of the sections later.
1772 sgen_client_pre_collection_checks ();
1774 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1775 /* Remsets are not useful for a major collection */
1776 remset.clear_cards ();
1779 sgen_process_fin_stage_entries ();
1782 sgen_init_pinning ();
1783 SGEN_LOG (6, "Collecting pinned addresses");
1784 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1785 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1786 /* Pin cemented objects that were forced */
1787 sgen_pin_cemented_objects ();
1789 sgen_optimize_pin_queue ();
1790 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1792 * Cemented objects that are in the pinned list will be marked. When
1793 * marking concurrently we won't mark mod-union cards for these objects.
1794 * Instead they will remain cemented until the next major collection,
1795 * when we will recheck if they are still pinned in the roots.
1797 sgen_cement_force_pinned ();
1800 sgen_client_collecting_major_1 ();
1803 * pin_queue now contains all candidate pointers, sorted and
1804 * uniqued. We must do two passes now to figure out which
1805 * objects are pinned.
1807 * The first is to find within the pin_queue the area for each
1808 * section. This requires that the pin_queue be sorted. We
1809 * also process the LOS objects and pinned chunks here.
1811 * The second, destructive, pass is to reduce the section
1812 * areas to pointers to the actually pinned objects.
1814 SGEN_LOG (6, "Pinning from sections");
1815 /* first pass for the sections */
1816 sgen_find_section_pin_queue_start_end (nursery_section);
1817 /* identify possible pointers to the insize of large objects */
1818 SGEN_LOG (6, "Pinning from large objects");
1819 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1821 if (sgen_find_optimized_pin_queue_area ((char*)bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1822 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
1824 if (sgen_los_object_is_pinned (bigobj->data)) {
1825 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1828 sgen_los_pin_object (bigobj->data);
1829 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1830 GRAY_OBJECT_ENQUEUE_SERIAL (gc_thread_gray_queue, bigobj->data, sgen_obj_get_descriptor ((GCObject*)bigobj->data));
1831 sgen_pin_stats_register_object (bigobj->data, GENERATION_OLD);
1832 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1833 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1834 (unsigned long)sgen_los_object_size (bigobj));
1836 sgen_client_pinned_los_object (bigobj->data);
1840 pin_objects_in_nursery (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT, ctx);
1841 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1842 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1844 major_collector.pin_objects (gc_thread_gray_queue);
1845 if (old_next_pin_slot)
1846 *old_next_pin_slot = sgen_get_pinned_count ();
1849 time_major_pinning += TV_ELAPSED (atv, btv);
1850 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (atv, btv));
1851 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1853 major_collector.init_to_space ();
1855 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1856 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1857 sgen_workers_set_num_active_workers (0);
1858 if (sgen_workers_have_idle_work ()) {
1860 * We force the finish of the worker with the new object ops context
1861 * which can also do copying. We need to have finished pinning.
1863 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1865 sgen_workers_join ();
1869 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1870 main_gc_thread = mono_native_thread_self ();
1873 sgen_client_collecting_major_2 ();
1876 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1878 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1880 enqueue_scan_from_roots_jobs (gc_thread_gray_queue, heap_start, heap_end, object_ops_nopar, FALSE);
1883 time_major_scan_roots += TV_ELAPSED (atv, btv);
1886 * We start the concurrent worker after pinning and after we scanned the roots
1887 * in order to make sure that the worker does not finish before handling all
1890 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1891 sgen_workers_set_num_active_workers (1);
1892 gray_queue_redirect (gc_thread_gray_queue);
1893 if (precleaning_enabled) {
1894 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, workers_finish_callback);
1896 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1900 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1901 int i, split_count = sgen_workers_get_job_split_count ();
1903 gray_queue_redirect (gc_thread_gray_queue);
1905 /* Mod union card table */
1906 for (i = 0; i < split_count; i++) {
1907 ParallelScanJob *psj;
1909 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ParallelScanJob));
1910 psj->scan_job.ops = object_ops_par ? object_ops_par : object_ops_nopar;
1911 psj->scan_job.gc_thread_gray_queue = NULL;
1913 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1915 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ParallelScanJob));
1916 psj->scan_job.ops = object_ops_par ? object_ops_par : object_ops_nopar;
1917 psj->scan_job.gc_thread_gray_queue = NULL;
1919 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1923 * If we enqueue a job while workers are running we need to sgen_workers_ensure_awake
1924 * in order to make sure that we are running the idle func and draining all worker
1925 * gray queues. The operation of starting workers implies this, so we start them after
1926 * in order to avoid doing this operation twice. The workers will drain the main gray
1927 * stack that contained roots and pinned objects and also scan the mod union card
1930 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1931 sgen_workers_join ();
1934 sgen_pin_stats_report ();
1936 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1937 sgen_finish_pinning ();
1939 sgen_pin_stats_reset ();
1941 if (do_concurrent_checks)
1942 sgen_debug_check_nursery_is_clean ();
1947 major_start_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean concurrent, size_t *old_next_pin_slot)
1949 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
1951 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
1953 current_collection_generation = GENERATION_OLD;
1955 sgen_workers_assert_gray_queue_is_empty ();
1958 sgen_cement_reset ();
1961 g_assert (major_collector.is_concurrent);
1962 concurrent_collection_in_progress = TRUE;
1964 object_ops_nopar = &major_collector.major_ops_concurrent_start;
1965 if (major_collector.is_parallel)
1966 object_ops_par = &major_collector.major_ops_conc_par_start;
1969 object_ops_nopar = &major_collector.major_ops_serial;
1972 reset_pinned_from_failed_allocation ();
1974 sgen_memgov_major_collection_start (concurrent, reason);
1976 //count_ref_nonref_objs ();
1977 //consistency_check ();
1979 check_scan_starts ();
1982 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
1983 gc_stats.major_gc_count ++;
1985 if (major_collector.start_major_collection)
1986 major_collector.start_major_collection ();
1988 major_copy_or_mark_from_roots (gc_thread_gray_queue, old_next_pin_slot, concurrent ? COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT : COPY_OR_MARK_FROM_ROOTS_SERIAL, object_ops_nopar, object_ops_par);
1992 major_finish_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean is_overflow, size_t old_next_pin_slot, gboolean forced)
1994 ScannedObjectCounts counts;
1995 SgenObjectOperations *object_ops_nopar;
1996 mword fragment_total;
2002 if (concurrent_collection_in_progress) {
2003 SgenObjectOperations *object_ops_par = NULL;
2005 object_ops_nopar = &major_collector.major_ops_concurrent_finish;
2006 if (major_collector.is_parallel)
2007 object_ops_par = &major_collector.major_ops_conc_par_finish;
2009 major_copy_or_mark_from_roots (gc_thread_gray_queue, NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, object_ops_nopar, object_ops_par);
2011 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2012 main_gc_thread = NULL;
2015 object_ops_nopar = &major_collector.major_ops_serial;
2018 sgen_workers_assert_gray_queue_is_empty ();
2020 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue));
2022 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2024 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2026 if (objects_pinned) {
2027 g_assert (!concurrent_collection_in_progress);
2030 * This is slow, but we just OOM'd.
2032 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2033 * queue is laid out at this point.
2035 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2037 * We need to reestablish all pinned nursery objects in the pin queue
2038 * because they're needed for fragment creation. Unpinning happens by
2039 * walking the whole queue, so it's not necessary to reestablish where major
2040 * heap block pins are - all we care is that they're still in there
2043 sgen_optimize_pin_queue ();
2044 sgen_find_section_pin_queue_start_end (nursery_section);
2048 reset_heap_boundaries ();
2049 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2051 /* walk the pin_queue, build up the fragment list of free memory, unmark
2052 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2055 fragment_total = sgen_build_nursery_fragments (nursery_section, NULL);
2056 if (!fragment_total)
2058 SGEN_LOG (4, "Free space in nursery after major %ld", (long)fragment_total);
2060 if (do_concurrent_checks && concurrent_collection_in_progress)
2061 sgen_debug_check_nursery_is_clean ();
2063 /* prepare the pin queue for the next collection */
2064 sgen_finish_pinning ();
2066 /* Clear TLABs for all threads */
2067 sgen_clear_tlabs ();
2069 sgen_pin_stats_reset ();
2071 sgen_cement_clear_below_threshold ();
2073 if (check_mark_bits_after_major_collection)
2074 sgen_check_heap_marked (concurrent_collection_in_progress);
2077 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2079 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2080 sgen_memgov_major_pre_sweep ();
2083 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2088 time_major_los_sweep += TV_ELAPSED (atv, btv);
2090 major_collector.sweep ();
2092 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2095 time_major_sweep += TV_ELAPSED (btv, atv);
2097 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2099 if (sgen_have_pending_finalizers ()) {
2100 SGEN_LOG (4, "Finalizer-thread wakeup");
2101 sgen_client_finalize_notify ();
2104 sgen_memgov_major_collection_end (forced, concurrent_collection_in_progress, reason, is_overflow);
2105 current_collection_generation = -1;
2107 memset (&counts, 0, sizeof (ScannedObjectCounts));
2108 major_collector.finish_major_collection (&counts);
2110 sgen_workers_assert_gray_queue_is_empty ();
2112 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2113 if (concurrent_collection_in_progress)
2114 concurrent_collection_in_progress = FALSE;
2116 check_scan_starts ();
2118 binary_protocol_flush_buffers (FALSE);
2120 //consistency_check ();
2122 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2126 major_do_collection (const char *reason, gboolean is_overflow, gboolean forced)
2128 TV_DECLARE (time_start);
2129 TV_DECLARE (time_end);
2130 size_t old_next_pin_slot;
2131 SgenGrayQueue gc_thread_gray_queue;
2133 if (disable_major_collections)
2136 if (major_collector.get_and_reset_num_major_objects_marked) {
2137 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2138 g_assert (!num_marked);
2141 /* world must be stopped already */
2142 TV_GETTIME (time_start);
2144 init_gray_queue (&gc_thread_gray_queue, FALSE);
2145 major_start_collection (&gc_thread_gray_queue, reason, FALSE, &old_next_pin_slot);
2146 major_finish_collection (&gc_thread_gray_queue, reason, is_overflow, old_next_pin_slot, forced);
2147 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2149 TV_GETTIME (time_end);
2150 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2152 /* FIXME: also report this to the user, preferably in gc-end. */
2153 if (major_collector.get_and_reset_num_major_objects_marked)
2154 major_collector.get_and_reset_num_major_objects_marked ();
2156 return bytes_pinned_from_failed_allocation > 0;
2160 major_start_concurrent_collection (const char *reason)
2162 TV_DECLARE (time_start);
2163 TV_DECLARE (time_end);
2164 long long num_objects_marked;
2165 SgenGrayQueue gc_thread_gray_queue;
2167 if (disable_major_collections)
2170 TV_GETTIME (time_start);
2171 SGEN_TV_GETTIME (time_major_conc_collection_start);
2173 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2174 g_assert (num_objects_marked == 0);
2176 binary_protocol_concurrent_start ();
2178 init_gray_queue (&gc_thread_gray_queue, TRUE);
2179 // FIXME: store reason and pass it when finishing
2180 major_start_collection (&gc_thread_gray_queue, reason, TRUE, NULL);
2181 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2183 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2185 TV_GETTIME (time_end);
2186 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2188 current_collection_generation = -1;
2192 * Returns whether the major collection has finished.
2195 major_should_finish_concurrent_collection (void)
2197 return sgen_workers_all_done ();
2201 major_update_concurrent_collection (void)
2203 TV_DECLARE (total_start);
2204 TV_DECLARE (total_end);
2206 TV_GETTIME (total_start);
2208 binary_protocol_concurrent_update ();
2210 major_collector.update_cardtable_mod_union ();
2211 sgen_los_update_cardtable_mod_union ();
2213 TV_GETTIME (total_end);
2214 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2218 major_finish_concurrent_collection (gboolean forced)
2220 SgenGrayQueue gc_thread_gray_queue;
2221 TV_DECLARE (total_start);
2222 TV_DECLARE (total_end);
2224 TV_GETTIME (total_start);
2226 binary_protocol_concurrent_finish ();
2229 * We need to stop all workers since we're updating the cardtable below.
2230 * The workers will be resumed with a finishing pause context to avoid
2231 * additional cardtable and object scanning.
2233 sgen_workers_stop_all_workers ();
2235 SGEN_TV_GETTIME (time_major_conc_collection_end);
2236 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2238 major_collector.update_cardtable_mod_union ();
2239 sgen_los_update_cardtable_mod_union ();
2241 if (mod_union_consistency_check)
2242 sgen_check_mod_union_consistency ();
2244 current_collection_generation = GENERATION_OLD;
2245 sgen_cement_reset ();
2246 init_gray_queue (&gc_thread_gray_queue, FALSE);
2247 major_finish_collection (&gc_thread_gray_queue, "finishing", FALSE, -1, forced);
2248 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2250 TV_GETTIME (total_end);
2251 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2253 current_collection_generation = -1;
2257 * Ensure an allocation request for @size will succeed by freeing enough memory.
2259 * LOCKING: The GC lock MUST be held.
2262 sgen_ensure_free_space (size_t size, int generation)
2264 int generation_to_collect = -1;
2265 const char *reason = NULL;
2267 if (generation == GENERATION_OLD) {
2268 if (sgen_need_major_collection (size)) {
2269 reason = "LOS overflow";
2270 generation_to_collect = GENERATION_OLD;
2273 if (degraded_mode) {
2274 if (sgen_need_major_collection (size)) {
2275 reason = "Degraded mode overflow";
2276 generation_to_collect = GENERATION_OLD;
2278 } else if (sgen_need_major_collection (size)) {
2279 reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
2280 generation_to_collect = GENERATION_OLD;
2282 generation_to_collect = GENERATION_NURSERY;
2283 reason = "Nursery full";
2287 if (generation_to_collect == -1) {
2288 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2289 generation_to_collect = GENERATION_OLD;
2290 reason = "Finish concurrent collection";
2294 if (generation_to_collect == -1)
2296 sgen_perform_collection (size, generation_to_collect, reason, FALSE, TRUE);
2300 * LOCKING: Assumes the GC lock is held.
2303 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw)
2305 TV_DECLARE (gc_total_start);
2306 TV_DECLARE (gc_total_end);
2307 int overflow_generation_to_collect = -1;
2308 int oldest_generation_collected = generation_to_collect;
2309 const char *overflow_reason = NULL;
2310 gboolean finish_concurrent = concurrent_collection_in_progress && (major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD);
2312 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2314 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2317 sgen_stop_world (generation_to_collect);
2319 SGEN_ASSERT (0, sgen_is_world_stopped (), "We can only collect if the world is stopped");
2322 TV_GETTIME (gc_total_start);
2324 // FIXME: extract overflow reason
2325 // FIXME: minor overflow for concurrent case
2326 if (generation_to_collect == GENERATION_NURSERY && !finish_concurrent) {
2327 if (concurrent_collection_in_progress)
2328 major_update_concurrent_collection ();
2330 if (collect_nursery (reason, FALSE, NULL) && !concurrent_collection_in_progress) {
2331 overflow_generation_to_collect = GENERATION_OLD;
2332 overflow_reason = "Minor overflow";
2334 } else if (finish_concurrent) {
2335 major_finish_concurrent_collection (wait_to_finish);
2336 oldest_generation_collected = GENERATION_OLD;
2338 SGEN_ASSERT (0, generation_to_collect == GENERATION_OLD, "We should have handled nursery collections above");
2339 if (major_collector.is_concurrent && !wait_to_finish) {
2340 collect_nursery ("Concurrent start", FALSE, NULL);
2341 major_start_concurrent_collection (reason);
2342 oldest_generation_collected = GENERATION_NURSERY;
2343 } else if (major_do_collection (reason, FALSE, wait_to_finish)) {
2344 overflow_generation_to_collect = GENERATION_NURSERY;
2345 overflow_reason = "Excessive pinning";
2349 if (overflow_generation_to_collect != -1) {
2350 SGEN_ASSERT (0, !concurrent_collection_in_progress, "We don't yet support overflow collections with the concurrent collector");
2353 * We need to do an overflow collection, either because we ran out of memory
2354 * or the nursery is fully pinned.
2357 if (overflow_generation_to_collect == GENERATION_NURSERY)
2358 collect_nursery (overflow_reason, TRUE, NULL);
2360 major_do_collection (overflow_reason, TRUE, wait_to_finish);
2362 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2365 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2367 /* this also sets the proper pointers for the next allocation */
2368 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2369 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2370 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2371 sgen_dump_pin_queue ();
2375 TV_GETTIME (gc_total_end);
2376 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2379 sgen_restart_world (oldest_generation_collected);
2383 * ######################################################################
2384 * ######## Memory allocation from the OS
2385 * ######################################################################
2386 * This section of code deals with getting memory from the OS and
2387 * allocating memory for GC-internal data structures.
2388 * Internal memory can be handled with a freelist for small objects.
2394 G_GNUC_UNUSED static void
2395 report_internal_mem_usage (void)
2397 printf ("Internal memory usage:\n");
2398 sgen_report_internal_mem_usage ();
2399 printf ("Pinned memory usage:\n");
2400 major_collector.report_pinned_memory_usage ();
2404 * ######################################################################
2405 * ######## Finalization support
2406 * ######################################################################
2410 * If the object has been forwarded it means it's still referenced from a root.
2411 * If it is pinned it's still alive as well.
2412 * A LOS object is only alive if we have pinned it.
2413 * Return TRUE if @obj is ready to be finalized.
2415 static inline gboolean
2416 sgen_is_object_alive (GCObject *object)
2418 if (ptr_in_nursery (object))
2419 return sgen_nursery_is_object_alive (object);
2421 return sgen_major_is_object_alive (object);
2425 * This function returns true if @object is either alive and belongs to the
2426 * current collection - major collections are full heap, so old gen objects
2427 * are never alive during a minor collection.
2430 sgen_is_object_alive_and_on_current_collection (GCObject *object)
2432 if (ptr_in_nursery (object))
2433 return sgen_nursery_is_object_alive (object);
2435 if (current_collection_generation == GENERATION_NURSERY)
2438 return sgen_major_is_object_alive (object);
2443 sgen_gc_is_object_ready_for_finalization (GCObject *object)
2445 return !sgen_is_object_alive (object);
2449 sgen_queue_finalization_entry (GCObject *obj)
2451 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2453 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2455 sgen_client_object_queued_for_finalization (obj);
2459 sgen_object_is_live (GCObject *obj)
2461 return sgen_is_object_alive_and_on_current_collection (obj);
2465 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2466 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2467 * all finalizers have really finished running.
2469 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2470 * This means that just checking whether the queues are empty leaves the possibility that an
2471 * object might have been dequeued but not yet finalized. That's why we need the additional
2472 * flag `pending_unqueued_finalizer`.
2475 static volatile gboolean pending_unqueued_finalizer = FALSE;
2476 volatile gboolean sgen_suspend_finalizers = FALSE;
2479 sgen_set_suspend_finalizers (void)
2481 sgen_suspend_finalizers = TRUE;
2485 sgen_gc_invoke_finalizers (void)
2489 g_assert (!pending_unqueued_finalizer);
2491 /* FIXME: batch to reduce lock contention */
2492 while (sgen_have_pending_finalizers ()) {
2498 * We need to set `pending_unqueued_finalizer` before dequeing the
2499 * finalizable object.
2501 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2502 pending_unqueued_finalizer = TRUE;
2503 mono_memory_write_barrier ();
2504 obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
2505 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2506 pending_unqueued_finalizer = TRUE;
2507 mono_memory_write_barrier ();
2508 obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
2514 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2522 /* the object is on the stack so it is pinned */
2523 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2524 sgen_client_run_finalize (obj);
2527 if (pending_unqueued_finalizer) {
2528 mono_memory_write_barrier ();
2529 pending_unqueued_finalizer = FALSE;
2536 sgen_have_pending_finalizers (void)
2538 if (sgen_suspend_finalizers)
2540 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2544 * ######################################################################
2545 * ######## registered roots support
2546 * ######################################################################
2550 * We do not coalesce roots.
2553 sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg)
2555 RootRecord new_root;
2558 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2559 RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
2560 /* we allow changing the size and the descriptor (for thread statics etc) */
2562 size_t old_size = root->end_root - start;
2563 root->end_root = start + size;
2564 SGEN_ASSERT (0, !!root->root_desc == !!descr, "Can't change whether a root is precise or conservative.");
2565 SGEN_ASSERT (0, root->source == source, "Can't change a root's source identifier.");
2566 SGEN_ASSERT (0, !!root->msg == !!msg, "Can't change a root's message.");
2567 root->root_desc = descr;
2569 roots_size -= old_size;
2575 new_root.end_root = start + size;
2576 new_root.root_desc = descr;
2577 new_root.source = source;
2580 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2583 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);
2590 sgen_deregister_root (char* addr)
2596 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2597 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2598 roots_size -= (root.end_root - addr);
2604 * ######################################################################
2605 * ######## Thread handling (stop/start code)
2606 * ######################################################################
2610 sgen_get_current_collection_generation (void)
2612 return current_collection_generation;
2616 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2618 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2620 sgen_client_thread_register (info, stack_bottom_fallback);
2626 sgen_thread_unregister (SgenThreadInfo *p)
2628 sgen_client_thread_unregister (p);
2632 * ######################################################################
2633 * ######## Write barriers
2634 * ######################################################################
2638 * Note: the write barriers first do the needed GC work and then do the actual store:
2639 * this way the value is visible to the conservative GC scan after the write barrier
2640 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2641 * the conservative scan, otherwise by the remembered set scan.
2645 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2647 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2648 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2649 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2650 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2654 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2655 if (binary_protocol_is_heavy_enabled ()) {
2657 for (i = 0; i < count; ++i) {
2658 gpointer dest = (gpointer*)dest_ptr + i;
2659 gpointer obj = *((gpointer*)src_ptr + i);
2661 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2666 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2670 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2674 HEAVY_STAT (++stat_wbarrier_generic_store);
2676 sgen_client_wbarrier_generic_nostore_check (ptr);
2678 obj = *(gpointer*)ptr;
2680 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2683 * We need to record old->old pointer locations for the
2684 * concurrent collector.
2686 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2687 SGEN_LOG (8, "Skipping remset at %p", ptr);
2691 SGEN_LOG (8, "Adding remset at %p", ptr);
2693 remset.wbarrier_generic_nostore (ptr);
2697 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2699 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2700 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2701 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2702 mono_gc_wbarrier_generic_nostore (ptr);
2703 sgen_dummy_use (value);
2706 /* Same as mono_gc_wbarrier_generic_store () but performs the store
2707 * as an atomic operation with release semantics.
2710 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2712 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2714 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2716 InterlockedWritePointer ((volatile gpointer *)ptr, value);
2718 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2719 mono_gc_wbarrier_generic_nostore (ptr);
2721 sgen_dummy_use (value);
2725 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
2727 GCObject **dest = (GCObject **)_dest;
2728 GCObject **src = (GCObject **)_src;
2732 mono_gc_wbarrier_generic_store (dest, *src);
2737 size -= SIZEOF_VOID_P;
2743 * ######################################################################
2744 * ######## Other mono public interface functions.
2745 * ######################################################################
2749 sgen_gc_collect (int generation)
2754 sgen_perform_collection (0, generation, "user request", TRUE, TRUE);
2759 sgen_gc_collection_count (int generation)
2761 if (generation == 0)
2762 return gc_stats.minor_gc_count;
2763 return gc_stats.major_gc_count;
2767 sgen_gc_get_used_size (void)
2771 tot = los_memory_usage;
2772 tot += nursery_section->next_data - nursery_section->data;
2773 tot += major_collector.get_used_size ();
2774 /* FIXME: account for pinned objects */
2780 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2784 va_start (ap, description_format);
2786 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2787 vfprintf (stderr, description_format, ap);
2789 fprintf (stderr, " - %s", fallback);
2790 fprintf (stderr, "\n");
2796 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2799 double val = strtod (opt, &endptr);
2800 if (endptr == opt) {
2801 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2804 else if (val < min || val > max) {
2805 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
2817 char *major_collector_opt = NULL;
2818 char *minor_collector_opt = NULL;
2819 char *params_opts = NULL;
2820 char *debug_opts = NULL;
2821 size_t max_heap = 0;
2822 size_t soft_limit = 0;
2824 gboolean debug_print_allowance = FALSE;
2825 double allowance_ratio = 0, save_target = 0;
2826 gboolean cement_enabled = TRUE;
2829 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
2832 /* already inited */
2835 /* being inited by another thread */
2836 mono_thread_info_usleep (1000);
2839 /* we will init it */
2842 g_assert_not_reached ();
2844 } while (result != 0);
2846 SGEN_TV_GETTIME (sgen_init_timestamp);
2848 #ifdef SGEN_WITHOUT_MONO
2849 mono_thread_smr_init ();
2852 mono_coop_mutex_init (&gc_mutex);
2854 gc_debug_file = stderr;
2856 mono_coop_mutex_init (&sgen_interruption_mutex);
2858 if ((env = g_getenv (MONO_GC_PARAMS_NAME)) || gc_params_options) {
2859 params_opts = g_strdup_printf ("%s,%s", gc_params_options ? gc_params_options : "", env ? env : "");
2863 opts = g_strsplit (params_opts, ",", -1);
2864 for (ptr = opts; *ptr; ++ptr) {
2866 if (g_str_has_prefix (opt, "major=")) {
2867 opt = strchr (opt, '=') + 1;
2868 major_collector_opt = g_strdup (opt);
2869 } else if (g_str_has_prefix (opt, "minor=")) {
2870 opt = strchr (opt, '=') + 1;
2871 minor_collector_opt = g_strdup (opt);
2879 sgen_init_internal_allocator ();
2880 sgen_init_nursery_allocator ();
2881 sgen_init_fin_weak_hash ();
2882 sgen_init_hash_table ();
2883 sgen_init_descriptors ();
2884 sgen_init_gray_queues ();
2885 sgen_init_allocator ();
2886 sgen_init_gchandles ();
2888 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
2889 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
2891 sgen_client_init ();
2893 if (!minor_collector_opt) {
2894 sgen_simple_nursery_init (&sgen_minor_collector);
2896 if (!strcmp (minor_collector_opt, "simple")) {
2898 sgen_simple_nursery_init (&sgen_minor_collector);
2899 } else if (!strcmp (minor_collector_opt, "split")) {
2900 sgen_split_nursery_init (&sgen_minor_collector);
2902 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
2903 goto use_simple_nursery;
2907 if (!major_collector_opt) {
2909 DEFAULT_MAJOR_INIT (&major_collector);
2910 } else if (!strcmp (major_collector_opt, "marksweep")) {
2911 sgen_marksweep_init (&major_collector);
2912 } else if (!strcmp (major_collector_opt, "marksweep-conc")) {
2913 sgen_marksweep_conc_init (&major_collector);
2914 } else if (!strcmp (major_collector_opt, "marksweep-conc-par")) {
2915 sgen_marksweep_conc_par_init (&major_collector);
2917 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `" DEFAULT_MAJOR_NAME "` instead.", "Unknown major collector `%s'.", major_collector_opt);
2918 goto use_default_major;
2921 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
2924 gboolean usage_printed = FALSE;
2926 for (ptr = opts; *ptr; ++ptr) {
2928 if (!strcmp (opt, ""))
2930 if (g_str_has_prefix (opt, "major="))
2932 if (g_str_has_prefix (opt, "minor="))
2934 if (g_str_has_prefix (opt, "max-heap-size=")) {
2935 size_t page_size = mono_pagesize ();
2936 size_t max_heap_candidate = 0;
2937 opt = strchr (opt, '=') + 1;
2938 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
2939 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
2940 if (max_heap != max_heap_candidate)
2941 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
2943 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
2947 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
2948 opt = strchr (opt, '=') + 1;
2949 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
2950 if (soft_limit <= 0) {
2951 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
2955 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
2961 if (g_str_has_prefix (opt, "nursery-size=")) {
2963 opt = strchr (opt, '=') + 1;
2964 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
2965 if ((val & (val - 1))) {
2966 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
2970 if (val < SGEN_MAX_NURSERY_WASTE) {
2971 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
2972 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
2976 sgen_nursery_size = val;
2977 sgen_nursery_bits = 0;
2978 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
2981 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
2987 if (g_str_has_prefix (opt, "save-target-ratio=")) {
2989 opt = strchr (opt, '=') + 1;
2990 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
2991 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
2996 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
2998 opt = strchr (opt, '=') + 1;
2999 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
3000 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3001 allowance_ratio = val;
3006 if (!strcmp (opt, "cementing")) {
3007 cement_enabled = TRUE;
3010 if (!strcmp (opt, "no-cementing")) {
3011 cement_enabled = FALSE;
3015 if (!strcmp (opt, "precleaning")) {
3016 precleaning_enabled = TRUE;
3019 if (!strcmp (opt, "no-precleaning")) {
3020 precleaning_enabled = FALSE;
3024 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3027 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3030 if (sgen_client_handle_gc_param (opt))
3033 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3038 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3039 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3040 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3041 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3042 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3043 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3044 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3045 fprintf (stderr, " [no-]cementing\n");
3046 if (major_collector.print_gc_param_usage)
3047 major_collector.print_gc_param_usage ();
3048 if (sgen_minor_collector.print_gc_param_usage)
3049 sgen_minor_collector.print_gc_param_usage ();
3050 sgen_client_print_gc_params_usage ();
3051 fprintf (stderr, " Experimental options:\n");
3052 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3053 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);
3054 fprintf (stderr, "\n");
3056 usage_printed = TRUE;
3061 if (major_collector_opt)
3062 g_free (major_collector_opt);
3064 if (minor_collector_opt)
3065 g_free (minor_collector_opt);
3068 g_free (params_opts);
3072 sgen_pinning_init ();
3073 sgen_cement_init (cement_enabled);
3075 if ((env = g_getenv (MONO_GC_DEBUG_NAME)) || gc_debug_options) {
3076 debug_opts = g_strdup_printf ("%s,%s", gc_debug_options ? gc_debug_options : "", env ? env : "");
3080 gboolean usage_printed = FALSE;
3082 opts = g_strsplit (debug_opts, ",", -1);
3083 for (ptr = opts; ptr && *ptr; ptr ++) {
3085 if (!strcmp (opt, ""))
3087 if (opt [0] >= '0' && opt [0] <= '9') {
3088 gc_debug_level = atoi (opt);
3093 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3094 gc_debug_file = fopen (rf, "wb");
3096 gc_debug_file = stderr;
3099 } else if (!strcmp (opt, "print-allowance")) {
3100 debug_print_allowance = TRUE;
3101 } else if (!strcmp (opt, "print-pinning")) {
3102 sgen_pin_stats_enable ();
3103 } else if (!strcmp (opt, "verify-before-allocs")) {
3104 verify_before_allocs = 1;
3105 has_per_allocation_action = TRUE;
3106 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3107 char *arg = strchr (opt, '=') + 1;
3108 verify_before_allocs = atoi (arg);
3109 has_per_allocation_action = TRUE;
3110 } else if (!strcmp (opt, "collect-before-allocs")) {
3111 collect_before_allocs = 1;
3112 has_per_allocation_action = TRUE;
3113 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3114 char *arg = strchr (opt, '=') + 1;
3115 has_per_allocation_action = TRUE;
3116 collect_before_allocs = atoi (arg);
3117 } else if (!strcmp (opt, "verify-before-collections")) {
3118 whole_heap_check_before_collection = TRUE;
3119 } else if (!strcmp (opt, "check-remset-consistency")) {
3120 remset_consistency_checks = TRUE;
3121 nursery_clear_policy = CLEAR_AT_GC;
3122 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3123 if (!major_collector.is_concurrent) {
3124 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3127 mod_union_consistency_check = TRUE;
3128 } else if (!strcmp (opt, "check-mark-bits")) {
3129 check_mark_bits_after_major_collection = TRUE;
3130 } else if (!strcmp (opt, "check-nursery-pinned")) {
3131 check_nursery_objects_pinned = TRUE;
3132 } else if (!strcmp (opt, "clear-at-gc")) {
3133 nursery_clear_policy = CLEAR_AT_GC;
3134 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3135 nursery_clear_policy = CLEAR_AT_GC;
3136 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3137 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3138 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3139 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3140 } else if (!strcmp (opt, "check-scan-starts")) {
3141 do_scan_starts_check = TRUE;
3142 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3143 do_verify_nursery = TRUE;
3144 } else if (!strcmp (opt, "check-concurrent")) {
3145 if (!major_collector.is_concurrent) {
3146 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3149 nursery_clear_policy = CLEAR_AT_GC;
3150 do_concurrent_checks = TRUE;
3151 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3152 do_dump_nursery_content = TRUE;
3153 } else if (!strcmp (opt, "disable-minor")) {
3154 disable_minor_collections = TRUE;
3155 } else if (!strcmp (opt, "disable-major")) {
3156 disable_major_collections = TRUE;
3157 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3158 char *filename = strchr (opt, '=') + 1;
3159 nursery_clear_policy = CLEAR_AT_GC;
3160 sgen_debug_enable_heap_dump (filename);
3161 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3162 char *filename = strchr (opt, '=') + 1;
3163 char *colon = strrchr (filename, ':');
3166 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3167 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3172 binary_protocol_init (filename, (long long)limit);
3173 } else if (!strcmp (opt, "nursery-canaries")) {
3174 do_verify_nursery = TRUE;
3175 enable_nursery_canaries = TRUE;
3176 } else if (!sgen_client_handle_gc_debug (opt)) {
3177 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3182 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);
3183 fprintf (stderr, "Valid <option>s are:\n");
3184 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3185 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3186 fprintf (stderr, " check-remset-consistency\n");
3187 fprintf (stderr, " check-mark-bits\n");
3188 fprintf (stderr, " check-nursery-pinned\n");
3189 fprintf (stderr, " verify-before-collections\n");
3190 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3191 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3192 fprintf (stderr, " disable-minor\n");
3193 fprintf (stderr, " disable-major\n");
3194 fprintf (stderr, " check-concurrent\n");
3195 fprintf (stderr, " clear-[nursery-]at-gc\n");
3196 fprintf (stderr, " clear-at-tlab-creation\n");
3197 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3198 fprintf (stderr, " check-scan-starts\n");
3199 fprintf (stderr, " print-allowance\n");
3200 fprintf (stderr, " print-pinning\n");
3201 fprintf (stderr, " heap-dump=<filename>\n");
3202 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3203 fprintf (stderr, " nursery-canaries\n");
3204 sgen_client_print_gc_debug_usage ();
3205 fprintf (stderr, "\n");
3207 usage_printed = TRUE;
3214 g_free (debug_opts);
3216 if (check_mark_bits_after_major_collection)
3217 nursery_clear_policy = CLEAR_AT_GC;
3219 if (major_collector.post_param_init)
3220 major_collector.post_param_init (&major_collector);
3222 if (major_collector.needs_thread_pool) {
3223 int num_workers = 1;
3224 if (major_collector.is_parallel) {
3225 /* FIXME Detect the number of physical cores, instead of logical */
3226 num_workers = mono_cpu_count () / 2;
3227 if (num_workers < 1)
3230 sgen_workers_init (num_workers, (SgenWorkerCallback) major_collector.worker_init_cb);
3233 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3235 memset (&remset, 0, sizeof (remset));
3237 sgen_card_table_init (&remset);
3239 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");
3243 sgen_init_bridge ();
3247 sgen_gc_initialized ()
3249 return gc_initialized > 0;
3253 sgen_get_nursery_clear_policy (void)
3255 return nursery_clear_policy;
3261 mono_coop_mutex_lock (&gc_mutex);
3265 sgen_gc_unlock (void)
3267 mono_coop_mutex_unlock (&gc_mutex);
3271 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3273 major_collector.iterate_live_block_ranges (callback);
3277 sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback)
3279 major_collector.iterate_block_ranges (callback);
3283 sgen_get_major_collector (void)
3285 return &major_collector;
3289 sgen_get_remset (void)
3295 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3297 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3298 sgen_los_count_cards (los_total, los_marked);
3301 static gboolean world_is_stopped = FALSE;
3303 /* LOCKING: assumes the GC lock is held */
3305 sgen_stop_world (int generation)
3307 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3309 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3311 binary_protocol_world_stopping (generation, sgen_timestamp (), (gpointer) (gsize) mono_native_thread_id_get ());
3313 sgen_client_stop_world (generation);
3315 world_is_stopped = TRUE;
3317 if (binary_protocol_is_heavy_enabled ())
3318 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3319 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3322 /* LOCKING: assumes the GC lock is held */
3324 sgen_restart_world (int generation)
3326 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3329 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3331 if (binary_protocol_is_heavy_enabled ())
3332 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3333 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3335 world_is_stopped = FALSE;
3337 sgen_client_restart_world (generation, &stw_time);
3339 binary_protocol_world_restarted (generation, sgen_timestamp ());
3341 if (sgen_client_bridge_need_processing ())
3342 sgen_client_bridge_processing_finish (generation);
3344 sgen_memgov_collection_end (generation, stw_time);
3348 sgen_is_world_stopped (void)
3350 return world_is_stopped;
3354 sgen_check_whole_heap_stw (void)
3356 sgen_stop_world (0);
3357 sgen_clear_nursery_fragments ();
3358 sgen_check_whole_heap (TRUE);
3359 sgen_restart_world (0);
3363 sgen_timestamp (void)
3365 SGEN_TV_DECLARE (timestamp);
3366 SGEN_TV_GETTIME (timestamp);
3367 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3370 #endif /* HAVE_SGEN_GC */