3 * Simple generational GC.
6 * Paolo Molaro (lupus@ximian.com)
7 * Rodrigo Kumpera (kumpera@gmail.com)
9 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
10 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
12 * Thread start/stop adapted from Boehm's GC:
13 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
14 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
15 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
16 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
17 * Copyright 2001-2003 Ximian, Inc
18 * Copyright 2003-2010 Novell, Inc.
19 * Copyright 2011 Xamarin, Inc.
20 * Copyright (C) 2012 Xamarin Inc
22 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
24 * Important: allocation provides always zeroed memory, having to do
25 * a memset after allocation is deadly for performance.
26 * Memory usage at startup is currently as follows:
28 * 64 KB internal space
30 * We should provide a small memory config with half the sizes
32 * We currently try to make as few mono assumptions as possible:
33 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
35 * 2) gc descriptor is the second word in the vtable (first word in the class)
36 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
37 * 4) there is a function to get an object's size and the number of
38 * elements in an array.
39 * 5) we know the special way bounds are allocated for complex arrays
40 * 6) we know about proxies and how to treat them when domains are unloaded
42 * Always try to keep stack usage to a minimum: no recursive behaviour
43 * and no large stack allocs.
45 * General description.
46 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
47 * When the nursery is full we start a nursery collection: this is performed with a
49 * When the old generation is full we start a copying GC of the old generation as well:
50 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
51 * in the future. Maybe we'll even do both during the same collection like IMMIX.
53 * The things that complicate this description are:
54 * *) pinned objects: we can't move them so we need to keep track of them
55 * *) no precise info of the thread stacks and registers: we need to be able to
56 * quickly find the objects that may be referenced conservatively and pin them
57 * (this makes the first issues more important)
58 * *) large objects are too expensive to be dealt with using copying GC: we handle them
59 * with mark/sweep during major collections
60 * *) some objects need to not move even if they are small (interned strings, Type handles):
61 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
62 * PinnedChunks regions
68 *) we could have a function pointer in MonoClass to implement
69 customized write barriers for value types
71 *) investigate the stuff needed to advance a thread to a GC-safe
72 point (single-stepping, read from unmapped memory etc) and implement it.
73 This would enable us to inline allocations and write barriers, for example,
74 or at least parts of them, like the write barrier checks.
75 We may need this also for handling precise info on stacks, even simple things
76 as having uninitialized data on the stack and having to wait for the prolog
77 to zero it. Not an issue for the last frame that we scan conservatively.
78 We could always not trust the value in the slots anyway.
80 *) modify the jit to save info about references in stack locations:
81 this can be done just for locals as a start, so that at least
82 part of the stack is handled precisely.
84 *) test/fix endianess issues
86 *) Implement a card table as the write barrier instead of remembered
87 sets? Card tables are not easy to implement with our current
88 memory layout. We have several different kinds of major heap
89 objects: Small objects in regular blocks, small objects in pinned
90 chunks and LOS objects. If we just have a pointer we have no way
91 to tell which kind of object it points into, therefore we cannot
92 know where its card table is. The least we have to do to make
93 this happen is to get rid of write barriers for indirect stores.
96 *) Get rid of write barriers for indirect stores. We can do this by
97 telling the GC to wbarrier-register an object once we do an ldloca
98 or ldelema on it, and to unregister it once it's not used anymore
99 (it can only travel downwards on the stack). The problem with
100 unregistering is that it needs to happen eventually no matter
101 what, even if exceptions are thrown, the thread aborts, etc.
102 Rodrigo suggested that we could do only the registering part and
103 let the collector find out (pessimistically) when it's safe to
104 unregister, namely when the stack pointer of the thread that
105 registered the object is higher than it was when the registering
106 happened. This might make for a good first implementation to get
107 some data on performance.
109 *) Some sort of blacklist support? Blacklists is a concept from the
110 Boehm GC: if during a conservative scan we find pointers to an
111 area which we might use as heap, we mark that area as unusable, so
112 pointer retention by random pinning pointers is reduced.
114 *) experiment with max small object size (very small right now - 2kb,
115 because it's tied to the max freelist size)
117 *) add an option to mmap the whole heap in one chunk: it makes for many
118 simplifications in the checks (put the nursery at the top and just use a single
119 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
120 not flexible (too much of the address space may be used by default or we can't
121 increase the heap as needed) and we'd need a race-free mechanism to return memory
122 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
123 was written to, munmap is needed, but the following mmap may not find the same segment
126 *) memzero the major fragments after restarting the world and optionally a smaller
129 *) investigate having fragment zeroing threads
131 *) separate locks for finalization and other minor stuff to reduce
134 *) try a different copying order to improve memory locality
136 *) a thread abort after a store but before the write barrier will
137 prevent the write barrier from executing
139 *) specialized dynamically generated markers/copiers
141 *) Dynamically adjust TLAB size to the number of threads. If we have
142 too many threads that do allocation, we might need smaller TLABs,
143 and we might get better performance with larger TLABs if we only
144 have a handful of threads. We could sum up the space left in all
145 assigned TLABs and if that's more than some percentage of the
146 nursery size, reduce the TLAB size.
148 *) Explore placing unreachable objects on unused nursery memory.
149 Instead of memset'ng a region to zero, place an int[] covering it.
150 A good place to start is add_nursery_frag. The tricky thing here is
151 placing those objects atomically outside of a collection.
153 *) Allocation should use asymmetric Dekker synchronization:
154 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
155 This should help weak consistency archs.
162 #define _XOPEN_SOURCE
163 #define _DARWIN_C_SOURCE
169 #ifdef HAVE_PTHREAD_H
172 #ifdef HAVE_PTHREAD_NP_H
173 #include <pthread_np.h>
181 #include "mono/sgen/sgen-gc.h"
182 #include "mono/sgen/sgen-cardtable.h"
183 #include "mono/sgen/sgen-protocol.h"
184 #include "mono/sgen/sgen-memory-governor.h"
185 #include "mono/sgen/sgen-hash-table.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>
196 #include <mono/utils/mono-mmap-internals.h>
198 #undef pthread_create
200 #undef pthread_detach
203 * ######################################################################
204 * ######## Types and constants used by the GC.
205 * ######################################################################
208 /* 0 means not initialized, 1 is initialized, -1 means in progress */
209 static int gc_initialized = 0;
210 /* If set, check if we need to do something every X allocations */
211 gboolean has_per_allocation_action;
212 /* If set, do a heap check every X allocation */
213 guint32 verify_before_allocs = 0;
214 /* If set, do a minor collection before every X allocation */
215 guint32 collect_before_allocs = 0;
216 /* If set, do a whole heap check before each collection */
217 static gboolean whole_heap_check_before_collection = FALSE;
218 /* If set, do a remset consistency check at various opportunities */
219 static gboolean remset_consistency_checks = FALSE;
220 /* If set, do a mod union consistency check before each finishing collection pause */
221 static gboolean mod_union_consistency_check = FALSE;
222 /* If set, check whether mark bits are consistent after major collections */
223 static gboolean check_mark_bits_after_major_collection = FALSE;
224 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
225 static gboolean check_nursery_objects_pinned = FALSE;
226 /* If set, do a few checks when the concurrent collector is used */
227 static gboolean do_concurrent_checks = FALSE;
228 /* If set, do a plausibility check on the scan_starts before and after
230 static gboolean do_scan_starts_check = FALSE;
232 static gboolean disable_minor_collections = FALSE;
233 static gboolean disable_major_collections = FALSE;
234 static gboolean do_verify_nursery = FALSE;
235 static gboolean do_dump_nursery_content = FALSE;
236 static gboolean enable_nursery_canaries = FALSE;
238 static gboolean precleaning_enabled = TRUE;
240 #ifdef HEAVY_STATISTICS
241 guint64 stat_objects_alloced_degraded = 0;
242 guint64 stat_bytes_alloced_degraded = 0;
244 guint64 stat_copy_object_called_nursery = 0;
245 guint64 stat_objects_copied_nursery = 0;
246 guint64 stat_copy_object_called_major = 0;
247 guint64 stat_objects_copied_major = 0;
249 guint64 stat_scan_object_called_nursery = 0;
250 guint64 stat_scan_object_called_major = 0;
252 guint64 stat_slots_allocated_in_vain;
254 guint64 stat_nursery_copy_object_failed_from_space = 0;
255 guint64 stat_nursery_copy_object_failed_forwarded = 0;
256 guint64 stat_nursery_copy_object_failed_pinned = 0;
257 guint64 stat_nursery_copy_object_failed_to_space = 0;
259 static guint64 stat_wbarrier_add_to_global_remset = 0;
260 static guint64 stat_wbarrier_arrayref_copy = 0;
261 static guint64 stat_wbarrier_generic_store = 0;
262 static guint64 stat_wbarrier_generic_store_atomic = 0;
263 static guint64 stat_wbarrier_set_root = 0;
266 static guint64 stat_pinned_objects = 0;
268 static guint64 time_minor_pre_collection_fragment_clear = 0;
269 static guint64 time_minor_pinning = 0;
270 static guint64 time_minor_scan_remsets = 0;
271 static guint64 time_minor_scan_major_blocks = 0;
272 static guint64 time_minor_scan_los = 0;
273 static guint64 time_minor_scan_pinned = 0;
274 static guint64 time_minor_scan_roots = 0;
275 static guint64 time_minor_finish_gray_stack = 0;
276 static guint64 time_minor_fragment_creation = 0;
278 static guint64 time_major_pre_collection_fragment_clear = 0;
279 static guint64 time_major_pinning = 0;
280 static guint64 time_major_scan_pinned = 0;
281 static guint64 time_major_scan_roots = 0;
282 static guint64 time_major_scan_mod_union = 0;
283 static guint64 time_major_finish_gray_stack = 0;
284 static guint64 time_major_free_bigobjs = 0;
285 static guint64 time_major_los_sweep = 0;
286 static guint64 time_major_sweep = 0;
287 static guint64 time_major_fragment_creation = 0;
289 static guint64 time_max = 0;
291 static int sgen_max_pause_time = SGEN_MAX_PAUSE_TIME;
292 static float sgen_max_pause_margin = SGEN_MAX_PAUSE_MARGIN;
294 static SGEN_TV_DECLARE (time_major_conc_collection_start);
295 static SGEN_TV_DECLARE (time_major_conc_collection_end);
297 int gc_debug_level = 0;
299 static char* gc_params_options;
300 static char* gc_debug_options;
304 mono_gc_flush_info (void)
306 fflush (gc_debug_file);
310 #define TV_DECLARE SGEN_TV_DECLARE
311 #define TV_GETTIME SGEN_TV_GETTIME
312 #define TV_ELAPSED SGEN_TV_ELAPSED
314 static SGEN_TV_DECLARE (sgen_init_timestamp);
316 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
318 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
319 #define object_is_pinned SGEN_OBJECT_IS_PINNED
320 #define pin_object SGEN_PIN_OBJECT
322 #define ptr_in_nursery sgen_ptr_in_nursery
324 #define LOAD_VTABLE SGEN_LOAD_VTABLE
327 nursery_canaries_enabled (void)
329 return enable_nursery_canaries;
332 #define safe_object_get_size sgen_safe_object_get_size
334 #if defined(HAVE_CONC_GC_AS_DEFAULT)
335 /* Use concurrent major on deskstop platforms */
336 #define DEFAULT_MAJOR_INIT sgen_marksweep_conc_init
337 #define DEFAULT_MAJOR_NAME "marksweep-conc"
339 #define DEFAULT_MAJOR_INIT sgen_marksweep_init
340 #define DEFAULT_MAJOR_NAME "marksweep"
344 * ######################################################################
345 * ######## Global data.
346 * ######################################################################
348 MonoCoopMutex gc_mutex;
350 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
352 size_t degraded_mode = 0;
354 static mword bytes_pinned_from_failed_allocation = 0;
356 GCMemSection *nursery_section = NULL;
357 static volatile mword lowest_heap_address = ~(mword)0;
358 static volatile mword highest_heap_address = 0;
360 MonoCoopMutex sgen_interruption_mutex;
362 int current_collection_generation = -1;
363 volatile gboolean concurrent_collection_in_progress = FALSE;
365 /* objects that are ready to be finalized */
366 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
367 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
369 /* registered roots: the key to the hash is the root start address */
371 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
373 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
374 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
375 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
376 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
378 static mword roots_size = 0; /* amount of memory in the root set */
380 /* The size of a TLAB */
381 /* The bigger the value, the less often we have to go to the slow path to allocate a new
382 * one, but the more space is wasted by threads not allocating much memory.
384 * FIXME: Make this self-tuning for each thread.
386 guint32 tlab_size = (1024 * 4);
388 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
390 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
392 #define ALIGN_UP SGEN_ALIGN_UP
394 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
395 MonoNativeThreadId main_gc_thread = NULL;
398 /*Object was pinned during the current collection*/
399 static mword objects_pinned;
402 * ######################################################################
403 * ######## Macros and function declarations.
404 * ######################################################################
407 /* forward declarations */
408 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
410 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
411 static void finish_gray_stack (int generation, ScanCopyContext ctx);
414 SgenMajorCollector major_collector;
415 SgenMinorCollector sgen_minor_collector;
417 static SgenRememberedSet remset;
420 * The gray queue a worker job must use. If we're not parallel or
421 * concurrent, we use the main gray queue.
423 static SgenGrayQueue*
424 sgen_workers_get_job_gray_queue (WorkerData *worker_data, SgenGrayQueue *default_gray_queue)
427 return &worker_data->private_gray_queue;
428 SGEN_ASSERT (0, default_gray_queue, "Why don't we have a default gray queue when we're not running in a worker thread?");
429 return default_gray_queue;
433 gray_queue_redirect (SgenGrayQueue *queue)
435 sgen_workers_take_from_queue (queue);
439 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries)
441 while (start < end) {
445 if (!*(void**)start) {
446 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
451 if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
457 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
458 CHECK_CANARY_FOR_OBJECT ((GCObject*)obj, fail_on_canaries);
459 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
460 callback ((GCObject*)obj, size, data);
461 CANARIFY_SIZE (size);
463 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
471 * sgen_add_to_global_remset:
473 * The global remset contains locations which point into newspace after
474 * a minor collection. This can happen if the objects they point to are pinned.
476 * LOCKING: If called from a parallel collector, the global remset
477 * lock must be held. For serial collectors that is not necessary.
480 sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
482 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
484 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
486 if (!major_collector.is_concurrent) {
487 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
489 if (current_collection_generation == -1)
490 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
493 if (!object_is_pinned (obj))
494 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");
495 else if (sgen_cement_lookup_or_register (obj))
498 remset.record_pointer (ptr);
500 sgen_pin_stats_register_global_remset (obj);
502 SGEN_LOG (8, "Adding global remset for %p", ptr);
503 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
507 * sgen_drain_gray_stack:
509 * Scan objects in the gray stack until the stack is empty. This should be called
510 * frequently after each object is copied, to achieve better locality and cache
515 sgen_drain_gray_stack (ScanCopyContext ctx)
517 SGEN_ASSERT (0, ctx.ops->drain_gray_stack, "Why do we have a scan/copy context with a missing drain gray stack function?");
519 return ctx.ops->drain_gray_stack (ctx.queue);
523 * Addresses in the pin queue are already sorted. This function finds
524 * the object header for each address and pins the object. The
525 * addresses must be inside the nursery section. The (start of the)
526 * address array is overwritten with the addresses of the actually
527 * pinned objects. Return the number of pinned objects.
530 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
532 GCMemSection *section = nursery_section;
533 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
534 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
535 void *start_nursery = section->data;
536 void *end_nursery = section->end_data;
541 void *pinning_front = start_nursery;
543 void **definitely_pinned = start;
544 ScanObjectFunc scan_func = ctx.ops->scan_object;
545 SgenGrayQueue *queue = ctx.queue;
547 sgen_nursery_allocator_prepare_for_pinning ();
549 while (start < end) {
550 GCObject *obj_to_pin = NULL;
551 size_t obj_to_pin_size = 0;
556 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
557 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
564 SGEN_LOG (5, "Considering pinning addr %p", addr);
565 /* We've already processed everything up to pinning_front. */
566 if (addr < pinning_front) {
572 * Find the closest scan start <= addr. We might search backward in the
573 * scan_starts array because entries might be NULL. In the worst case we
574 * start at start_nursery.
576 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
577 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
578 search_start = (void*)section->scan_starts [idx];
579 if (!search_start || search_start > addr) {
582 search_start = section->scan_starts [idx];
583 if (search_start && search_start <= addr)
586 if (!search_start || search_start > addr)
587 search_start = start_nursery;
591 * If the pinning front is closer than the scan start we found, start
592 * searching at the front.
594 if (search_start < pinning_front)
595 search_start = pinning_front;
598 * Now addr should be in an object a short distance from search_start.
600 * search_start must point to zeroed mem or point to an object.
603 size_t obj_size, canarified_obj_size;
606 if (!*(void**)search_start) {
607 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
608 /* The loop condition makes sure we don't overrun addr. */
612 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
615 * Filler arrays are marked by an invalid sync word. We don't
616 * consider them for pinning. They are not delimited by canaries,
619 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
620 CHECK_CANARY_FOR_OBJECT (search_start, TRUE);
621 CANARIFY_SIZE (canarified_obj_size);
623 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
624 /* This is the object we're looking for. */
625 obj_to_pin = (GCObject*)search_start;
626 obj_to_pin_size = canarified_obj_size;
631 /* Skip to the next object */
632 search_start = (void*)((char*)search_start + canarified_obj_size);
633 } while (search_start <= addr);
635 /* We've searched past the address we were looking for. */
637 pinning_front = search_start;
638 goto next_pin_queue_entry;
642 * We've found an object to pin. It might still be a dummy array, but we
643 * can advance the pinning front in any case.
645 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
648 * If this is a dummy array marking the beginning of a nursery
649 * fragment, we don't pin it.
651 if (sgen_client_object_is_array_fill (obj_to_pin))
652 goto next_pin_queue_entry;
655 * Finally - pin the object!
657 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
658 if (do_scan_objects) {
659 scan_func (obj_to_pin, desc, queue);
661 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
662 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
663 binary_protocol_pin (obj_to_pin,
664 (gpointer)LOAD_VTABLE (obj_to_pin),
665 safe_object_get_size (obj_to_pin));
667 pin_object (obj_to_pin);
668 GRAY_OBJECT_ENQUEUE_SERIAL (queue, obj_to_pin, desc);
669 sgen_pin_stats_register_object (obj_to_pin, GENERATION_NURSERY);
670 definitely_pinned [count] = obj_to_pin;
673 if (concurrent_collection_in_progress)
674 sgen_pinning_register_pinned_in_nursery (obj_to_pin);
676 next_pin_queue_entry:
680 sgen_client_nursery_objects_pinned (definitely_pinned, count);
681 stat_pinned_objects += count;
686 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
690 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
693 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
694 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
698 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
699 * when we can't promote an object because we're out of memory.
702 sgen_pin_object (GCObject *object, SgenGrayQueue *queue)
704 SGEN_ASSERT (0, sgen_ptr_in_nursery (object), "We're only supposed to use this for pinning nursery objects when out of memory.");
707 * All pinned objects are assumed to have been staged, so we need to stage as well.
708 * Also, the count of staged objects shows that "late pinning" happened.
710 sgen_pin_stage_ptr (object);
712 SGEN_PIN_OBJECT (object);
713 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
716 sgen_pin_stats_register_object (object, GENERATION_NURSERY);
718 GRAY_OBJECT_ENQUEUE_SERIAL (queue, object, sgen_obj_get_descriptor_safe (object));
721 /* Sort the addresses in array in increasing order.
722 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
725 sgen_sort_addresses (void **array, size_t size)
730 for (i = 1; i < size; ++i) {
733 size_t parent = (child - 1) / 2;
735 if (array [parent] >= array [child])
738 tmp = array [parent];
739 array [parent] = array [child];
746 for (i = size - 1; i > 0; --i) {
749 array [i] = array [0];
755 while (root * 2 + 1 <= end) {
756 size_t child = root * 2 + 1;
758 if (child < end && array [child] < array [child + 1])
760 if (array [root] >= array [child])
764 array [root] = array [child];
773 * Scan the memory between start and end and queue values which could be pointers
774 * to the area between start_nursery and end_nursery for later consideration.
775 * Typically used for thread stacks.
778 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
782 SGEN_ASSERT (0, ((mword)start & (SIZEOF_VOID_P - 1)) == 0, "Why are we scanning for references in unaligned memory ?");
784 #if defined(VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE) && !defined(_WIN64)
785 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
788 while (start < end) {
790 * *start can point to the middle of an object
791 * note: should we handle pointing at the end of an object?
792 * pinning in C# code disallows pointing at the end of an object
793 * but there is some small chance that an optimizing C compiler
794 * may keep the only reference to an object by pointing
795 * at the end of it. We ignore this small chance for now.
796 * Pointers to the end of an object are indistinguishable
797 * from pointers to the start of the next object in memory
798 * so if we allow that we'd need to pin two objects...
799 * We queue the pointer in an array, the
800 * array will then be sorted and uniqued. This way
801 * we can coalesce several pinning pointers and it should
802 * be faster since we'd do a memory scan with increasing
803 * addresses. Note: we can align the address to the allocation
804 * alignment, so the unique process is more effective.
806 mword addr = (mword)*start;
807 addr &= ~(ALLOC_ALIGN - 1);
808 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
809 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
810 sgen_pin_stage_ptr ((void*)addr);
811 binary_protocol_pin_stage (start, (void*)addr);
812 sgen_pin_stats_register_address ((char*)addr, pin_type);
818 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
822 * The first thing we do in a collection is to identify pinned objects.
823 * This function considers all the areas of memory that need to be
824 * conservatively scanned.
827 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
831 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);
832 /* objects pinned from the API are inside these roots */
833 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
834 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
835 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
836 } SGEN_HASH_TABLE_FOREACH_END;
837 /* now deal with the thread stacks
838 * in the future we should be able to conservatively scan only:
839 * *) the cpu registers
840 * *) the unmanaged stack frames
841 * *) the _last_ managed stack frame
842 * *) pointers slots in managed frames
844 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
848 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
850 ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
851 ctx->ops->copy_or_mark_object (obj, ctx->queue);
855 * The memory area from start_root to end_root contains pointers to objects.
856 * Their position is precisely described by @desc (this means that the pointer
857 * can be either NULL or the pointer to the start of an object).
858 * This functions copies them to to_space updates them.
860 * This function is not thread-safe!
863 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, SgenDescriptor desc, ScanCopyContext ctx)
865 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
866 ScanPtrFieldFunc scan_field_func = ctx.ops->scan_ptr_field;
867 SgenGrayQueue *queue = ctx.queue;
869 switch (desc & ROOT_DESC_TYPE_MASK) {
870 case ROOT_DESC_BITMAP:
871 desc >>= ROOT_DESC_TYPE_SHIFT;
873 if ((desc & 1) && *start_root) {
874 copy_func ((GCObject**)start_root, queue);
875 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
881 case ROOT_DESC_COMPLEX: {
882 gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
883 gsize bwords = (*bitmap_data) - 1;
884 void **start_run = start_root;
886 while (bwords-- > 0) {
887 gsize bmap = *bitmap_data++;
888 void **objptr = start_run;
890 if ((bmap & 1) && *objptr) {
891 copy_func ((GCObject**)objptr, queue);
892 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
897 start_run += GC_BITS_PER_WORD;
901 case ROOT_DESC_VECTOR: {
904 for (p = start_root; p < end_root; p++) {
906 scan_field_func (NULL, (GCObject**)p, queue);
910 case ROOT_DESC_USER: {
911 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
912 marker (start_root, single_arg_user_copy_or_mark, &ctx);
915 case ROOT_DESC_RUN_LEN:
916 g_assert_not_reached ();
918 g_assert_not_reached ();
923 reset_heap_boundaries (void)
925 lowest_heap_address = ~(mword)0;
926 highest_heap_address = 0;
930 sgen_update_heap_boundaries (mword low, mword high)
935 old = lowest_heap_address;
938 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
941 old = highest_heap_address;
944 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
948 * Allocate and setup the data structures needed to be able to allocate objects
949 * in the nursery. The nursery is stored in nursery_section.
952 alloc_nursery (gboolean dynamic, size_t min_size, size_t max_size)
959 min_size = SGEN_DEFAULT_NURSERY_MIN_SIZE;
961 max_size = SGEN_DEFAULT_NURSERY_MAX_SIZE;
963 SGEN_ASSERT (0, min_size == max_size, "We can't have nursery ranges for static configuration.");
965 min_size = max_size = SGEN_DEFAULT_NURSERY_SIZE;
968 SGEN_ASSERT (0, !nursery_section, "Why are we allocating the nursery twice?");
969 SGEN_LOG (2, "Allocating nursery size: %zu, initial %zu", max_size, min_size);
971 /* FIXME: handle OOM */
972 nursery_section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
974 /* If there isn't enough space even for the nursery we should simply abort. */
975 g_assert (sgen_memgov_try_alloc_space (max_size, SPACE_NURSERY));
978 * The nursery section range represents the memory section where objects
979 * can be found. This is used when iterating for objects in the nursery,
980 * pinning etc. sgen_nursery_max_size represents the total allocated space
981 * for the nursery. sgen_nursery_size represents the current size of the
982 * nursery and it is used for allocation limits, heuristics etc. The
983 * nursery section is not always identical to the current nursery size
984 * because it can contain pinned objects from when the nursery was larger.
986 * sgen_nursery_size <= nursery_section size <= sgen_nursery_max_size
988 data = (char *)major_collector.alloc_heap (max_size, max_size);
989 sgen_update_heap_boundaries ((mword)data, (mword)(data + max_size));
990 nursery_section->data = data;
991 nursery_section->end_data = data + min_size;
992 scan_starts = (max_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
993 nursery_section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
994 nursery_section->num_scan_start = scan_starts;
996 sgen_nursery_allocator_set_nursery_bounds (data, min_size, max_size);
1000 mono_gc_get_logfile (void)
1002 return gc_debug_file;
1006 mono_gc_params_set (const char* options)
1008 if (gc_params_options)
1009 g_free (gc_params_options);
1011 gc_params_options = g_strdup (options);
1015 mono_gc_debug_set (const char* options)
1017 if (gc_debug_options)
1018 g_free (gc_debug_options);
1020 gc_debug_options = g_strdup (options);
1024 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1026 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1027 SgenGrayQueue *queue = ctx.queue;
1030 for (i = 0; i < fin_queue->next_slot; ++i) {
1031 GCObject *obj = (GCObject *)fin_queue->data [i];
1034 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1035 copy_func ((GCObject**)&fin_queue->data [i], queue);
1040 generation_name (int generation)
1042 switch (generation) {
1043 case GENERATION_NURSERY: return "nursery";
1044 case GENERATION_OLD: return "old";
1045 default: g_assert_not_reached ();
1050 sgen_generation_name (int generation)
1052 return generation_name (generation);
1056 finish_gray_stack (int generation, ScanCopyContext ctx)
1060 int done_with_ephemerons, ephemeron_rounds = 0;
1061 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1062 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1063 SgenGrayQueue *queue = ctx.queue;
1065 binary_protocol_finish_gray_stack_start (sgen_timestamp (), generation);
1067 * We copied all the reachable objects. Now it's the time to copy
1068 * the objects that were not referenced by the roots, but by the copied objects.
1069 * we built a stack of objects pointed to by gray_start: they are
1070 * additional roots and we may add more items as we go.
1071 * We loop until gray_start == gray_objects which means no more objects have
1072 * been added. Note this is iterative: no recursion is involved.
1073 * We need to walk the LO list as well in search of marked big objects
1074 * (use a flag since this is needed only on major collections). We need to loop
1075 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1076 * To achieve better cache locality and cache usage, we drain the gray stack
1077 * frequently, after each object is copied, and just finish the work here.
1079 sgen_drain_gray_stack (ctx);
1081 SGEN_LOG (2, "%s generation done", generation_name (generation));
1084 Reset bridge data, we might have lingering data from a previous collection if this is a major
1085 collection trigged by minor overflow.
1087 We must reset the gathered bridges since their original block might be evacuated due to major
1088 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1090 if (sgen_client_bridge_need_processing ())
1091 sgen_client_bridge_reset_data ();
1094 * Mark all strong toggleref objects. This must be done before we walk ephemerons or finalizers
1095 * to ensure they see the full set of live objects.
1097 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1100 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1101 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1102 * objects that are in fact reachable.
1104 done_with_ephemerons = 0;
1106 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1107 sgen_drain_gray_stack (ctx);
1109 } while (!done_with_ephemerons);
1111 if (sgen_client_bridge_need_processing ()) {
1112 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1113 sgen_drain_gray_stack (ctx);
1114 sgen_collect_bridge_objects (generation, ctx);
1115 if (generation == GENERATION_OLD)
1116 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1119 Do the first bridge step here, as the collector liveness state will become useless after that.
1121 An important optimization is to only proccess the possibly dead part of the object graph and skip
1122 over all live objects as we transitively know everything they point must be alive too.
1124 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1126 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1127 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1130 sgen_client_bridge_processing_stw_step ();
1134 Make sure we drain the gray stack before processing disappearing links and finalizers.
1135 If we don't make sure it is empty we might wrongly see a live object as dead.
1137 sgen_drain_gray_stack (ctx);
1140 We must clear weak links that don't track resurrection before processing object ready for
1141 finalization so they can be cleared before that.
1143 sgen_null_link_in_range (generation, ctx, FALSE);
1144 if (generation == GENERATION_OLD)
1145 sgen_null_link_in_range (GENERATION_NURSERY, ctx, FALSE);
1148 /* walk the finalization queue and move also the objects that need to be
1149 * finalized: use the finalized objects as new roots so the objects they depend
1150 * on are also not reclaimed. As with the roots above, only objects in the nursery
1151 * are marked/copied.
1153 sgen_finalize_in_range (generation, ctx);
1154 if (generation == GENERATION_OLD)
1155 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1156 /* drain the new stack that might have been created */
1157 SGEN_LOG (6, "Precise scan of gray area post fin");
1158 sgen_drain_gray_stack (ctx);
1161 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1163 done_with_ephemerons = 0;
1165 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1166 sgen_drain_gray_stack (ctx);
1168 } while (!done_with_ephemerons);
1170 sgen_client_clear_unreachable_ephemerons (ctx);
1173 * We clear togglerefs only after all possible chances of revival are done.
1174 * This is semantically more inline with what users expect and it allows for
1175 * user finalizers to correctly interact with TR objects.
1177 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1180 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);
1183 * handle disappearing links
1184 * Note we do this after checking the finalization queue because if an object
1185 * survives (at least long enough to be finalized) we don't clear the link.
1186 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1187 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1190 g_assert (sgen_gray_object_queue_is_empty (queue));
1192 sgen_null_link_in_range (generation, ctx, TRUE);
1193 if (generation == GENERATION_OLD)
1194 sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
1195 if (sgen_gray_object_queue_is_empty (queue))
1197 sgen_drain_gray_stack (ctx);
1200 g_assert (sgen_gray_object_queue_is_empty (queue));
1202 binary_protocol_finish_gray_stack_end (sgen_timestamp (), generation);
1206 sgen_check_section_scan_starts (GCMemSection *section)
1209 for (i = 0; i < section->num_scan_start; ++i) {
1210 if (section->scan_starts [i]) {
1211 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1212 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1218 check_scan_starts (void)
1220 if (!do_scan_starts_check)
1222 sgen_check_section_scan_starts (nursery_section);
1223 major_collector.check_scan_starts ();
1227 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1231 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
1232 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1233 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1234 } SGEN_HASH_TABLE_FOREACH_END;
1240 static gboolean inited = FALSE;
1245 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1247 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1248 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1249 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1250 mono_counters_register ("Minor scan major blocks", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_major_blocks);
1251 mono_counters_register ("Minor scan los", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_los);
1252 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1253 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1254 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1256 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1257 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1258 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1259 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1260 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1261 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1262 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1263 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1264 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1265 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1267 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1269 #ifdef HEAVY_STATISTICS
1270 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1271 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1272 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1273 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1274 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1276 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1277 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1279 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1280 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1281 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1282 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1284 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1285 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1287 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1289 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1290 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1291 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1292 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1294 sgen_nursery_allocator_init_heavy_stats ();
1302 reset_pinned_from_failed_allocation (void)
1304 bytes_pinned_from_failed_allocation = 0;
1308 sgen_set_pinned_from_failed_allocation (mword objsize)
1310 bytes_pinned_from_failed_allocation += objsize;
1314 sgen_collection_is_concurrent (void)
1316 switch (current_collection_generation) {
1317 case GENERATION_NURSERY:
1319 case GENERATION_OLD:
1320 return concurrent_collection_in_progress;
1322 g_error ("Invalid current generation %d", current_collection_generation);
1328 sgen_concurrent_collection_in_progress (void)
1330 return concurrent_collection_in_progress;
1334 SgenThreadPoolJob job;
1335 SgenObjectOperations *ops;
1336 SgenGrayQueue *gc_thread_gray_queue;
1344 static ScanCopyContext
1345 scan_copy_context_for_scan_job (void *worker_data_untyped, ScanJob *job)
1347 WorkerData *worker_data = (WorkerData *)worker_data_untyped;
1351 * For jobs enqueued on workers we set the ops at job runtime in order
1352 * to be able to profit from on the fly optimized object ops or other
1353 * object ops changes, like forced concurrent finish.
1355 SGEN_ASSERT (0, sgen_workers_is_worker_thread (mono_native_thread_id_get ()), "We need a context for the scan job");
1356 job->ops = sgen_workers_get_idle_func_object_ops ();
1359 return CONTEXT_FROM_OBJECT_OPERATIONS (job->ops, sgen_workers_get_job_gray_queue (worker_data, job->gc_thread_gray_queue));
1367 } ScanFromRegisteredRootsJob;
1370 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1372 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1373 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1375 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1382 } ScanThreadDataJob;
1385 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1387 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1388 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1390 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1395 SgenPointerQueue *queue;
1396 } ScanFinalizerEntriesJob;
1399 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1401 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1402 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1404 scan_finalizer_entries (job_data->queue, ctx);
1408 job_scan_wbroots (void *worker_data_untyped, SgenThreadPoolJob *job)
1410 ScanJob *job_data = (ScanJob*)job;
1411 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1413 sgen_wbroots_scan_card_table (ctx);
1417 job_scan_major_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1419 SGEN_TV_DECLARE (atv);
1420 SGEN_TV_DECLARE (btv);
1421 ParallelScanJob *job_data = (ParallelScanJob*)job;
1422 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1424 SGEN_TV_GETTIME (atv);
1425 major_collector.scan_card_table (CARDTABLE_SCAN_GLOBAL, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1426 SGEN_TV_GETTIME (btv);
1427 time_minor_scan_major_blocks += SGEN_TV_ELAPSED (atv, btv);
1431 job_scan_los_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1433 SGEN_TV_DECLARE (atv);
1434 SGEN_TV_DECLARE (btv);
1435 ParallelScanJob *job_data = (ParallelScanJob*)job;
1436 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1438 SGEN_TV_GETTIME (atv);
1439 sgen_los_scan_card_table (CARDTABLE_SCAN_GLOBAL, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1440 SGEN_TV_GETTIME (btv);
1441 time_minor_scan_los += SGEN_TV_ELAPSED (atv, btv);
1445 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1447 ParallelScanJob *job_data = (ParallelScanJob*)job;
1448 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1450 g_assert (concurrent_collection_in_progress);
1451 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1455 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1457 ParallelScanJob *job_data = (ParallelScanJob*)job;
1458 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1460 g_assert (concurrent_collection_in_progress);
1461 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1465 job_major_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1467 ParallelScanJob *job_data = (ParallelScanJob*)job;
1468 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1470 g_assert (concurrent_collection_in_progress);
1472 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1476 job_los_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1478 ParallelScanJob *job_data = (ParallelScanJob*)job;
1479 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1481 g_assert (concurrent_collection_in_progress);
1483 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1487 job_scan_last_pinned (void *worker_data_untyped, SgenThreadPoolJob *job)
1489 ScanJob *job_data = (ScanJob*)job;
1490 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1492 g_assert (concurrent_collection_in_progress);
1494 sgen_scan_pin_queue_objects (ctx);
1498 workers_finish_callback (void)
1500 ParallelScanJob *psj;
1502 int split_count = sgen_workers_get_job_split_count ();
1504 /* Mod union preclean jobs */
1505 for (i = 0; i < split_count; i++) {
1506 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean major mod union cardtable", job_major_mod_union_preclean, sizeof (ParallelScanJob));
1507 psj->scan_job.gc_thread_gray_queue = NULL;
1509 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1512 for (i = 0; i < split_count; i++) {
1513 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean los mod union cardtable", job_los_mod_union_preclean, sizeof (ParallelScanJob));
1514 psj->scan_job.gc_thread_gray_queue = NULL;
1516 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1519 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan last pinned", job_scan_last_pinned, sizeof (ScanJob));
1520 sj->gc_thread_gray_queue = NULL;
1521 sgen_workers_enqueue_job (&sj->job, TRUE);
1525 init_gray_queue (SgenGrayQueue *gc_thread_gray_queue, gboolean use_workers)
1528 sgen_workers_init_distribute_gray_queue ();
1529 sgen_gray_object_queue_init (gc_thread_gray_queue, NULL, TRUE);
1533 enqueue_scan_remembered_set_jobs (SgenGrayQueue *gc_thread_gray_queue, SgenObjectOperations *ops, gboolean enqueue)
1535 int i, split_count = sgen_workers_get_job_split_count ();
1538 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan wbroots", job_scan_wbroots, sizeof (ScanJob));
1540 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1541 sgen_workers_enqueue_job (&sj->job, enqueue);
1543 for (i = 0; i < split_count; i++) {
1544 ParallelScanJob *psj;
1546 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan major remsets", job_scan_major_card_table, sizeof (ParallelScanJob));
1547 psj->scan_job.ops = ops;
1548 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1550 sgen_workers_enqueue_job (&psj->scan_job.job, enqueue);
1552 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS remsets", job_scan_los_card_table, sizeof (ParallelScanJob));
1553 psj->scan_job.ops = ops;
1554 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1556 sgen_workers_enqueue_job (&psj->scan_job.job, enqueue);
1561 enqueue_scan_from_roots_jobs (SgenGrayQueue *gc_thread_gray_queue, char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
1563 ScanFromRegisteredRootsJob *scrrj;
1564 ScanThreadDataJob *stdj;
1565 ScanFinalizerEntriesJob *sfej;
1567 /* registered roots, this includes static fields */
1569 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1570 scrrj->scan_job.ops = ops;
1571 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1572 scrrj->heap_start = heap_start;
1573 scrrj->heap_end = heap_end;
1574 scrrj->root_type = ROOT_TYPE_NORMAL;
1575 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1577 if (current_collection_generation == GENERATION_OLD) {
1578 /* During minors we scan the cardtable for these roots instead */
1579 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1580 scrrj->scan_job.ops = ops;
1581 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1582 scrrj->heap_start = heap_start;
1583 scrrj->heap_end = heap_end;
1584 scrrj->root_type = ROOT_TYPE_WBARRIER;
1585 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1590 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1591 stdj->scan_job.ops = ops;
1592 stdj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1593 stdj->heap_start = heap_start;
1594 stdj->heap_end = heap_end;
1595 sgen_workers_enqueue_job (&stdj->scan_job.job, enqueue);
1597 /* Scan the list of objects ready for finalization. */
1599 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1600 sfej->scan_job.ops = ops;
1601 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1602 sfej->queue = &fin_ready_queue;
1603 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1605 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1606 sfej->scan_job.ops = ops;
1607 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1608 sfej->queue = &critical_fin_queue;
1609 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1613 * Perform a nursery collection.
1615 * Return whether any objects were late-pinned due to being out of memory.
1618 collect_nursery (const char *reason, gboolean is_overflow, SgenGrayQueue *unpin_queue)
1620 gboolean needs_major, is_parallel = FALSE;
1621 mword fragment_total;
1622 SgenGrayQueue gc_thread_gray_queue;
1623 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
1624 ScanCopyContext ctx;
1628 SGEN_TV_DECLARE (last_minor_collection_start_tv);
1629 SGEN_TV_DECLARE (last_minor_collection_end_tv);
1631 if (disable_minor_collections)
1634 TV_GETTIME (last_minor_collection_start_tv);
1635 atv = last_minor_collection_start_tv;
1637 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1639 if (sgen_concurrent_collection_in_progress ()) {
1640 /* FIXME Support parallel nursery collections with concurrent major */
1641 object_ops_nopar = &sgen_minor_collector.serial_ops_with_concurrent_major;
1643 object_ops_nopar = &sgen_minor_collector.serial_ops;
1644 if (sgen_minor_collector.is_parallel) {
1645 object_ops_par = &sgen_minor_collector.parallel_ops;
1650 if (do_verify_nursery || do_dump_nursery_content)
1651 sgen_debug_verify_nursery (do_dump_nursery_content);
1653 current_collection_generation = GENERATION_NURSERY;
1655 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1657 reset_pinned_from_failed_allocation ();
1659 check_scan_starts ();
1661 sgen_nursery_alloc_prepare_for_minor ();
1666 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", gc_stats.minor_gc_count, nursery_section->data, nursery_section->end_data, (int)(nursery_section->end_data - nursery_section->data));
1668 /* world must be stopped already */
1670 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1672 sgen_client_pre_collection_checks ();
1674 major_collector.start_nursery_collection ();
1676 sgen_memgov_minor_collection_start ();
1678 init_gray_queue (&gc_thread_gray_queue, is_parallel);
1679 ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, &gc_thread_gray_queue);
1681 gc_stats.minor_gc_count ++;
1683 sgen_process_fin_stage_entries ();
1685 /* pin from pinned handles */
1686 sgen_init_pinning ();
1687 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1688 pin_from_roots (nursery_section->data, nursery_section->end_data, ctx);
1689 /* pin cemented objects */
1690 sgen_pin_cemented_objects ();
1691 /* identify pinned objects */
1692 sgen_optimize_pin_queue ();
1693 sgen_pinning_setup_section (nursery_section);
1695 pin_objects_in_nursery (FALSE, ctx);
1696 sgen_pinning_trim_queue_to_section (nursery_section);
1698 if (remset_consistency_checks)
1699 sgen_check_remset_consistency ();
1701 if (whole_heap_check_before_collection) {
1702 sgen_clear_nursery_fragments ();
1703 sgen_check_whole_heap (FALSE);
1707 time_minor_pinning += TV_ELAPSED (btv, atv);
1708 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (btv, atv));
1709 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1711 remset.start_scan_remsets ();
1713 enqueue_scan_remembered_set_jobs (&gc_thread_gray_queue, is_parallel ? NULL : object_ops_nopar, is_parallel);
1715 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1717 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1718 SGEN_LOG (2, "Old generation scan: %lld usecs", (long long)TV_ELAPSED (atv, btv));
1720 sgen_pin_stats_report ();
1722 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1723 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1726 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1728 enqueue_scan_from_roots_jobs (&gc_thread_gray_queue, nursery_section->data, nursery_section->end_data, is_parallel ? NULL : object_ops_nopar, is_parallel);
1731 gray_queue_redirect (&gc_thread_gray_queue);
1732 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1733 sgen_workers_join ();
1737 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1739 finish_gray_stack (GENERATION_NURSERY, ctx);
1742 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1743 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1745 if (objects_pinned) {
1746 sgen_optimize_pin_queue ();
1747 sgen_pinning_setup_section (nursery_section);
1751 * This is the latest point at which we can do this check, because
1752 * sgen_build_nursery_fragments() unpins nursery objects again.
1754 if (remset_consistency_checks)
1755 sgen_check_remset_consistency ();
1759 duration = (int)(TV_ELAPSED (last_minor_collection_start_tv, btv) / 10000);
1760 if (duration > (sgen_max_pause_time * sgen_max_pause_margin))
1761 sgen_resize_nursery (TRUE);
1763 sgen_resize_nursery (FALSE);
1765 /* walk the pin_queue, build up the fragment list of free memory, unmark
1766 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1769 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1770 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1771 if (!fragment_total)
1774 /* Clear TLABs for all threads */
1775 sgen_clear_tlabs ();
1777 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1779 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1780 SGEN_LOG (2, "Fragment creation: %lld usecs, %lu bytes available", (long long)TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1782 if (remset_consistency_checks)
1783 sgen_check_major_refs ();
1785 major_collector.finish_nursery_collection ();
1787 TV_GETTIME (last_minor_collection_end_tv);
1788 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1790 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1792 /* prepare the pin queue for the next collection */
1793 sgen_finish_pinning ();
1794 if (sgen_have_pending_finalizers ()) {
1795 SGEN_LOG (4, "Finalizer-thread wakeup");
1796 sgen_client_finalize_notify ();
1798 sgen_pin_stats_reset ();
1799 /* clear cemented hash */
1800 sgen_cement_clear_below_threshold ();
1802 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
1804 check_scan_starts ();
1806 binary_protocol_flush_buffers (FALSE);
1808 sgen_memgov_minor_collection_end (reason, is_overflow);
1810 /*objects are late pinned because of lack of memory, so a major is a good call*/
1811 needs_major = objects_pinned > 0;
1812 current_collection_generation = -1;
1815 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1817 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1818 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1824 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1825 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1826 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1827 } CopyOrMarkFromRootsMode;
1830 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)
1835 /* FIXME: only use these values for the precise scan
1836 * note that to_space pointers should be excluded anyway...
1838 char *heap_start = NULL;
1839 char *heap_end = (char*)-1;
1840 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue);
1841 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1843 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1845 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1846 /*This cleans up unused fragments */
1847 sgen_nursery_allocator_prepare_for_pinning ();
1849 if (do_concurrent_checks)
1850 sgen_debug_check_nursery_is_clean ();
1852 /* The concurrent collector doesn't touch the nursery. */
1853 sgen_nursery_alloc_prepare_for_major ();
1858 /* Pinning depends on this */
1859 sgen_clear_nursery_fragments ();
1861 if (whole_heap_check_before_collection)
1862 sgen_check_whole_heap (TRUE);
1865 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1869 sgen_client_pre_collection_checks ();
1871 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1872 /* Remsets are not useful for a major collection */
1873 remset.clear_cards ();
1876 sgen_process_fin_stage_entries ();
1879 sgen_init_pinning ();
1880 SGEN_LOG (6, "Collecting pinned addresses");
1881 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1882 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1883 /* Pin cemented objects that were forced */
1884 sgen_pin_cemented_objects ();
1886 sgen_optimize_pin_queue ();
1887 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1889 * Cemented objects that are in the pinned list will be marked. When
1890 * marking concurrently we won't mark mod-union cards for these objects.
1891 * Instead they will remain cemented until the next major collection,
1892 * when we will recheck if they are still pinned in the roots.
1894 sgen_cement_force_pinned ();
1897 sgen_client_collecting_major_1 ();
1900 * pin_queue now contains all candidate pointers, sorted and
1901 * uniqued. We must do two passes now to figure out which
1902 * objects are pinned.
1904 * The first is to find within the pin_queue the area for each
1905 * section. This requires that the pin_queue be sorted. We
1906 * also process the LOS objects and pinned chunks here.
1908 * The second, destructive, pass is to reduce the section
1909 * areas to pointers to the actually pinned objects.
1911 SGEN_LOG (6, "Pinning from sections");
1912 /* first pass for the sections */
1913 sgen_find_section_pin_queue_start_end (nursery_section);
1914 /* identify possible pointers to the insize of large objects */
1915 SGEN_LOG (6, "Pinning from large objects");
1916 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1918 if (sgen_find_optimized_pin_queue_area ((char*)bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1919 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
1921 if (sgen_los_object_is_pinned (bigobj->data)) {
1922 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1925 sgen_los_pin_object (bigobj->data);
1926 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1927 GRAY_OBJECT_ENQUEUE_SERIAL (gc_thread_gray_queue, bigobj->data, sgen_obj_get_descriptor ((GCObject*)bigobj->data));
1928 sgen_pin_stats_register_object (bigobj->data, GENERATION_OLD);
1929 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1930 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1931 (unsigned long)sgen_los_object_size (bigobj));
1933 sgen_client_pinned_los_object (bigobj->data);
1937 pin_objects_in_nursery (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT, ctx);
1938 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1939 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1941 major_collector.pin_objects (gc_thread_gray_queue);
1942 if (old_next_pin_slot)
1943 *old_next_pin_slot = sgen_get_pinned_count ();
1946 time_major_pinning += TV_ELAPSED (atv, btv);
1947 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (atv, btv));
1948 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1950 major_collector.init_to_space ();
1952 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1953 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1954 if (object_ops_par != NULL)
1955 sgen_workers_set_num_active_workers (0);
1956 if (sgen_workers_have_idle_work ()) {
1958 * We force the finish of the worker with the new object ops context
1959 * which can also do copying. We need to have finished pinning.
1961 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1963 sgen_workers_join ();
1967 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1968 main_gc_thread = mono_native_thread_self ();
1971 sgen_client_collecting_major_2 ();
1974 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1976 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1978 enqueue_scan_from_roots_jobs (gc_thread_gray_queue, heap_start, heap_end, object_ops_nopar, FALSE);
1981 time_major_scan_roots += TV_ELAPSED (atv, btv);
1984 * We start the concurrent worker after pinning and after we scanned the roots
1985 * in order to make sure that the worker does not finish before handling all
1988 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1989 sgen_workers_set_num_active_workers (1);
1990 gray_queue_redirect (gc_thread_gray_queue);
1991 if (precleaning_enabled) {
1992 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, workers_finish_callback);
1994 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1998 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1999 int i, split_count = sgen_workers_get_job_split_count ();
2000 gboolean parallel = object_ops_par != NULL;
2002 /* If we're not parallel we finish the collection on the gc thread */
2004 gray_queue_redirect (gc_thread_gray_queue);
2006 /* Mod union card table */
2007 for (i = 0; i < split_count; i++) {
2008 ParallelScanJob *psj;
2010 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ParallelScanJob));
2011 psj->scan_job.ops = parallel ? NULL : object_ops_nopar;
2012 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
2014 sgen_workers_enqueue_job (&psj->scan_job.job, parallel);
2016 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ParallelScanJob));
2017 psj->scan_job.ops = parallel ? NULL : object_ops_nopar;
2018 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
2020 sgen_workers_enqueue_job (&psj->scan_job.job, parallel);
2025 * If we enqueue a job while workers are running we need to sgen_workers_ensure_awake
2026 * in order to make sure that we are running the idle func and draining all worker
2027 * gray queues. The operation of starting workers implies this, so we start them after
2028 * in order to avoid doing this operation twice. The workers will drain the main gray
2029 * stack that contained roots and pinned objects and also scan the mod union card
2032 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
2033 sgen_workers_join ();
2037 sgen_pin_stats_report ();
2039 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
2040 sgen_finish_pinning ();
2042 sgen_pin_stats_reset ();
2044 if (do_concurrent_checks)
2045 sgen_debug_check_nursery_is_clean ();
2050 major_start_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean concurrent, size_t *old_next_pin_slot)
2052 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
2054 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2056 current_collection_generation = GENERATION_OLD;
2058 sgen_workers_assert_gray_queue_is_empty ();
2061 sgen_cement_reset ();
2064 g_assert (major_collector.is_concurrent);
2065 concurrent_collection_in_progress = TRUE;
2067 object_ops_nopar = &major_collector.major_ops_concurrent_start;
2068 if (major_collector.is_parallel)
2069 object_ops_par = &major_collector.major_ops_conc_par_start;
2072 object_ops_nopar = &major_collector.major_ops_serial;
2075 reset_pinned_from_failed_allocation ();
2077 sgen_memgov_major_collection_start (concurrent, reason);
2079 //count_ref_nonref_objs ();
2080 //consistency_check ();
2082 check_scan_starts ();
2085 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2086 gc_stats.major_gc_count ++;
2088 if (major_collector.start_major_collection)
2089 major_collector.start_major_collection ();
2091 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);
2095 major_finish_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean is_overflow, size_t old_next_pin_slot, gboolean forced)
2097 ScannedObjectCounts counts;
2098 SgenObjectOperations *object_ops_nopar;
2099 mword fragment_total;
2105 if (concurrent_collection_in_progress) {
2106 SgenObjectOperations *object_ops_par = NULL;
2108 object_ops_nopar = &major_collector.major_ops_concurrent_finish;
2109 if (major_collector.is_parallel)
2110 object_ops_par = &major_collector.major_ops_conc_par_finish;
2112 major_copy_or_mark_from_roots (gc_thread_gray_queue, NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, object_ops_nopar, object_ops_par);
2114 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2115 main_gc_thread = NULL;
2118 object_ops_nopar = &major_collector.major_ops_serial;
2121 sgen_workers_assert_gray_queue_is_empty ();
2123 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue));
2125 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2127 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2129 if (objects_pinned) {
2130 g_assert (!concurrent_collection_in_progress);
2133 * This is slow, but we just OOM'd.
2135 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2136 * queue is laid out at this point.
2138 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2140 * We need to reestablish all pinned nursery objects in the pin queue
2141 * because they're needed for fragment creation. Unpinning happens by
2142 * walking the whole queue, so it's not necessary to reestablish where major
2143 * heap block pins are - all we care is that they're still in there
2146 sgen_optimize_pin_queue ();
2147 sgen_find_section_pin_queue_start_end (nursery_section);
2151 reset_heap_boundaries ();
2152 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2154 /* walk the pin_queue, build up the fragment list of free memory, unmark
2155 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2158 fragment_total = sgen_build_nursery_fragments (nursery_section, NULL);
2159 if (!fragment_total)
2161 SGEN_LOG (4, "Free space in nursery after major %ld", (long)fragment_total);
2163 if (do_concurrent_checks && concurrent_collection_in_progress)
2164 sgen_debug_check_nursery_is_clean ();
2166 /* prepare the pin queue for the next collection */
2167 sgen_finish_pinning ();
2169 /* Clear TLABs for all threads */
2170 sgen_clear_tlabs ();
2172 sgen_pin_stats_reset ();
2174 sgen_cement_clear_below_threshold ();
2176 if (check_mark_bits_after_major_collection)
2177 sgen_check_heap_marked (concurrent_collection_in_progress);
2180 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2182 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2183 sgen_memgov_major_pre_sweep ();
2186 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2191 time_major_los_sweep += TV_ELAPSED (atv, btv);
2193 major_collector.sweep ();
2195 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2198 time_major_sweep += TV_ELAPSED (btv, atv);
2200 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2202 if (sgen_have_pending_finalizers ()) {
2203 SGEN_LOG (4, "Finalizer-thread wakeup");
2204 sgen_client_finalize_notify ();
2207 sgen_memgov_major_collection_end (forced, concurrent_collection_in_progress, reason, is_overflow);
2208 current_collection_generation = -1;
2210 memset (&counts, 0, sizeof (ScannedObjectCounts));
2211 major_collector.finish_major_collection (&counts);
2213 sgen_workers_assert_gray_queue_is_empty ();
2215 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2216 if (concurrent_collection_in_progress)
2217 concurrent_collection_in_progress = FALSE;
2219 check_scan_starts ();
2221 binary_protocol_flush_buffers (FALSE);
2223 //consistency_check ();
2225 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2229 major_do_collection (const char *reason, gboolean is_overflow, gboolean forced)
2231 TV_DECLARE (time_start);
2232 TV_DECLARE (time_end);
2233 size_t old_next_pin_slot;
2234 SgenGrayQueue gc_thread_gray_queue;
2236 if (disable_major_collections)
2239 if (major_collector.get_and_reset_num_major_objects_marked) {
2240 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2241 g_assert (!num_marked);
2244 /* world must be stopped already */
2245 TV_GETTIME (time_start);
2247 init_gray_queue (&gc_thread_gray_queue, FALSE);
2248 major_start_collection (&gc_thread_gray_queue, reason, FALSE, &old_next_pin_slot);
2249 major_finish_collection (&gc_thread_gray_queue, reason, is_overflow, old_next_pin_slot, forced);
2250 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2252 TV_GETTIME (time_end);
2253 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2255 /* FIXME: also report this to the user, preferably in gc-end. */
2256 if (major_collector.get_and_reset_num_major_objects_marked)
2257 major_collector.get_and_reset_num_major_objects_marked ();
2259 return bytes_pinned_from_failed_allocation > 0;
2263 major_start_concurrent_collection (const char *reason)
2265 TV_DECLARE (time_start);
2266 TV_DECLARE (time_end);
2267 long long num_objects_marked;
2268 SgenGrayQueue gc_thread_gray_queue;
2270 if (disable_major_collections)
2273 TV_GETTIME (time_start);
2274 SGEN_TV_GETTIME (time_major_conc_collection_start);
2276 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2277 g_assert (num_objects_marked == 0);
2279 binary_protocol_concurrent_start ();
2281 init_gray_queue (&gc_thread_gray_queue, TRUE);
2282 // FIXME: store reason and pass it when finishing
2283 major_start_collection (&gc_thread_gray_queue, reason, TRUE, NULL);
2284 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2286 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2288 TV_GETTIME (time_end);
2289 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2291 current_collection_generation = -1;
2295 * Returns whether the major collection has finished.
2298 major_should_finish_concurrent_collection (void)
2300 return sgen_workers_all_done ();
2304 major_update_concurrent_collection (void)
2306 TV_DECLARE (total_start);
2307 TV_DECLARE (total_end);
2309 TV_GETTIME (total_start);
2311 binary_protocol_concurrent_update ();
2313 major_collector.update_cardtable_mod_union ();
2314 sgen_los_update_cardtable_mod_union ();
2316 TV_GETTIME (total_end);
2317 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2321 major_finish_concurrent_collection (gboolean forced)
2323 SgenGrayQueue gc_thread_gray_queue;
2324 TV_DECLARE (total_start);
2325 TV_DECLARE (total_end);
2327 TV_GETTIME (total_start);
2329 binary_protocol_concurrent_finish ();
2332 * We need to stop all workers since we're updating the cardtable below.
2333 * The workers will be resumed with a finishing pause context to avoid
2334 * additional cardtable and object scanning.
2336 sgen_workers_stop_all_workers ();
2338 SGEN_TV_GETTIME (time_major_conc_collection_end);
2339 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2341 major_collector.update_cardtable_mod_union ();
2342 sgen_los_update_cardtable_mod_union ();
2344 if (mod_union_consistency_check)
2345 sgen_check_mod_union_consistency ();
2347 current_collection_generation = GENERATION_OLD;
2348 sgen_cement_reset ();
2349 init_gray_queue (&gc_thread_gray_queue, FALSE);
2350 major_finish_collection (&gc_thread_gray_queue, "finishing", FALSE, -1, forced);
2351 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2353 TV_GETTIME (total_end);
2354 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2356 current_collection_generation = -1;
2360 * Ensure an allocation request for @size will succeed by freeing enough memory.
2362 * LOCKING: The GC lock MUST be held.
2365 sgen_ensure_free_space (size_t size, int generation)
2367 int generation_to_collect = -1;
2368 const char *reason = NULL;
2370 if (generation == GENERATION_OLD) {
2371 if (sgen_need_major_collection (size)) {
2372 reason = "LOS overflow";
2373 generation_to_collect = GENERATION_OLD;
2376 if (degraded_mode) {
2377 if (sgen_need_major_collection (size)) {
2378 reason = "Degraded mode overflow";
2379 generation_to_collect = GENERATION_OLD;
2381 } else if (sgen_need_major_collection (size)) {
2382 reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
2383 generation_to_collect = GENERATION_OLD;
2385 generation_to_collect = GENERATION_NURSERY;
2386 reason = "Nursery full";
2390 if (generation_to_collect == -1) {
2391 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2392 generation_to_collect = GENERATION_OLD;
2393 reason = "Finish concurrent collection";
2397 if (generation_to_collect == -1)
2399 sgen_perform_collection (size, generation_to_collect, reason, FALSE, TRUE);
2403 * LOCKING: Assumes the GC lock is held.
2406 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw)
2408 TV_DECLARE (gc_total_start);
2409 TV_DECLARE (gc_total_end);
2410 int overflow_generation_to_collect = -1;
2411 int oldest_generation_collected = generation_to_collect;
2412 const char *overflow_reason = NULL;
2413 gboolean finish_concurrent = concurrent_collection_in_progress && (major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD);
2415 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2417 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2420 sgen_stop_world (generation_to_collect);
2422 SGEN_ASSERT (0, sgen_is_world_stopped (), "We can only collect if the world is stopped");
2425 TV_GETTIME (gc_total_start);
2427 // FIXME: extract overflow reason
2428 // FIXME: minor overflow for concurrent case
2429 if (generation_to_collect == GENERATION_NURSERY && !finish_concurrent) {
2430 if (concurrent_collection_in_progress)
2431 major_update_concurrent_collection ();
2433 if (collect_nursery (reason, FALSE, NULL) && !concurrent_collection_in_progress) {
2434 overflow_generation_to_collect = GENERATION_OLD;
2435 overflow_reason = "Minor overflow";
2437 } else if (finish_concurrent) {
2438 major_finish_concurrent_collection (wait_to_finish);
2439 oldest_generation_collected = GENERATION_OLD;
2441 SGEN_ASSERT (0, generation_to_collect == GENERATION_OLD, "We should have handled nursery collections above");
2442 if (major_collector.is_concurrent && !wait_to_finish) {
2443 collect_nursery ("Concurrent start", FALSE, NULL);
2444 major_start_concurrent_collection (reason);
2445 oldest_generation_collected = GENERATION_NURSERY;
2446 } else if (major_do_collection (reason, FALSE, wait_to_finish)) {
2447 overflow_generation_to_collect = GENERATION_NURSERY;
2448 overflow_reason = "Excessive pinning";
2452 if (overflow_generation_to_collect != -1) {
2453 SGEN_ASSERT (0, !concurrent_collection_in_progress, "We don't yet support overflow collections with the concurrent collector");
2456 * We need to do an overflow collection, either because we ran out of memory
2457 * or the nursery is fully pinned.
2460 if (overflow_generation_to_collect == GENERATION_NURSERY)
2461 collect_nursery (overflow_reason, TRUE, NULL);
2463 major_do_collection (overflow_reason, TRUE, wait_to_finish);
2465 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2468 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2470 /* this also sets the proper pointers for the next allocation */
2471 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2472 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2473 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2474 sgen_dump_pin_queue ();
2478 TV_GETTIME (gc_total_end);
2479 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2482 sgen_restart_world (oldest_generation_collected);
2486 * ######################################################################
2487 * ######## Memory allocation from the OS
2488 * ######################################################################
2489 * This section of code deals with getting memory from the OS and
2490 * allocating memory for GC-internal data structures.
2491 * Internal memory can be handled with a freelist for small objects.
2497 G_GNUC_UNUSED static void
2498 report_internal_mem_usage (void)
2500 printf ("Internal memory usage:\n");
2501 sgen_report_internal_mem_usage ();
2502 printf ("Pinned memory usage:\n");
2503 major_collector.report_pinned_memory_usage ();
2507 * ######################################################################
2508 * ######## Finalization support
2509 * ######################################################################
2513 * If the object has been forwarded it means it's still referenced from a root.
2514 * If it is pinned it's still alive as well.
2515 * A LOS object is only alive if we have pinned it.
2516 * Return TRUE if @obj is ready to be finalized.
2518 static inline gboolean
2519 sgen_is_object_alive (GCObject *object)
2521 if (ptr_in_nursery (object))
2522 return sgen_nursery_is_object_alive (object);
2524 return sgen_major_is_object_alive (object);
2528 * This function returns true if @object is either alive and belongs to the
2529 * current collection - major collections are full heap, so old gen objects
2530 * are never alive during a minor collection.
2533 sgen_is_object_alive_and_on_current_collection (GCObject *object)
2535 if (ptr_in_nursery (object))
2536 return sgen_nursery_is_object_alive (object);
2538 if (current_collection_generation == GENERATION_NURSERY)
2541 return sgen_major_is_object_alive (object);
2546 sgen_gc_is_object_ready_for_finalization (GCObject *object)
2548 return !sgen_is_object_alive (object);
2552 sgen_queue_finalization_entry (GCObject *obj)
2554 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2556 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2558 sgen_client_object_queued_for_finalization (obj);
2562 sgen_object_is_live (GCObject *obj)
2564 return sgen_is_object_alive_and_on_current_collection (obj);
2568 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2569 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2570 * all finalizers have really finished running.
2572 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2573 * This means that just checking whether the queues are empty leaves the possibility that an
2574 * object might have been dequeued but not yet finalized. That's why we need the additional
2575 * flag `pending_unqueued_finalizer`.
2578 static volatile gboolean pending_unqueued_finalizer = FALSE;
2579 volatile gboolean sgen_suspend_finalizers = FALSE;
2582 sgen_set_suspend_finalizers (void)
2584 sgen_suspend_finalizers = TRUE;
2588 sgen_gc_invoke_finalizers (void)
2592 g_assert (!pending_unqueued_finalizer);
2594 /* FIXME: batch to reduce lock contention */
2595 while (sgen_have_pending_finalizers ()) {
2601 * We need to set `pending_unqueued_finalizer` before dequeing the
2602 * finalizable object.
2604 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2605 pending_unqueued_finalizer = TRUE;
2606 mono_memory_write_barrier ();
2607 obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
2608 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2609 pending_unqueued_finalizer = TRUE;
2610 mono_memory_write_barrier ();
2611 obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
2617 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2625 /* the object is on the stack so it is pinned */
2626 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2627 sgen_client_run_finalize (obj);
2630 if (pending_unqueued_finalizer) {
2631 mono_memory_write_barrier ();
2632 pending_unqueued_finalizer = FALSE;
2639 sgen_have_pending_finalizers (void)
2641 if (sgen_suspend_finalizers)
2643 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2647 * ######################################################################
2648 * ######## registered roots support
2649 * ######################################################################
2653 * We do not coalesce roots.
2656 sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg)
2658 RootRecord new_root;
2661 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2662 RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
2663 /* we allow changing the size and the descriptor (for thread statics etc) */
2665 size_t old_size = root->end_root - start;
2666 root->end_root = start + size;
2667 SGEN_ASSERT (0, !!root->root_desc == !!descr, "Can't change whether a root is precise or conservative.");
2668 SGEN_ASSERT (0, root->source == source, "Can't change a root's source identifier.");
2669 SGEN_ASSERT (0, !!root->msg == !!msg, "Can't change a root's message.");
2670 root->root_desc = descr;
2672 roots_size -= old_size;
2678 new_root.end_root = start + size;
2679 new_root.root_desc = descr;
2680 new_root.source = source;
2683 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2686 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);
2693 sgen_deregister_root (char* addr)
2699 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2700 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2701 roots_size -= (root.end_root - addr);
2707 sgen_wbroots_iterate_live_block_ranges (sgen_cardtable_block_callback cb)
2711 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_WBARRIER], void **, start_root, RootRecord *, root) {
2712 cb ((mword)start_root, (mword)root->end_root - (mword)start_root);
2713 } SGEN_HASH_TABLE_FOREACH_END;
2716 /* Root equivalent of sgen_client_cardtable_scan_object */
2718 sgen_wbroot_scan_card_table (void** start_root, mword size, ScanCopyContext ctx)
2720 ScanPtrFieldFunc scan_field_func = ctx.ops->scan_ptr_field;
2721 guint8 *card_data = sgen_card_table_get_card_scan_address ((mword)start_root);
2722 guint8 *card_base = card_data;
2723 mword card_count = sgen_card_table_number_of_cards_in_range ((mword)start_root, size);
2724 guint8 *card_data_end = card_data + card_count;
2725 mword extra_idx = 0;
2726 char *obj_start = sgen_card_table_align_pointer (start_root);
2727 char *obj_end = (char*)start_root + size;
2728 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2729 guint8 *overflow_scan_end = NULL;
2732 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2733 /*Check for overflow and if so, setup to scan in two steps*/
2734 if (card_data_end >= SGEN_SHADOW_CARDTABLE_END) {
2735 overflow_scan_end = sgen_shadow_cardtable + (card_data_end - SGEN_SHADOW_CARDTABLE_END);
2736 card_data_end = SGEN_SHADOW_CARDTABLE_END;
2742 card_data = sgen_find_next_card (card_data, card_data_end);
2744 for (; card_data < card_data_end; card_data = sgen_find_next_card (card_data + 1, card_data_end)) {
2745 size_t idx = (card_data - card_base) + extra_idx;
2746 char *start = (char*)(obj_start + idx * CARD_SIZE_IN_BYTES);
2747 char *card_end = start + CARD_SIZE_IN_BYTES;
2748 char *elem = start, *first_elem = start;
2751 * Don't clean first and last card on 32bit systems since they
2752 * may also be part from other roots.
2754 if (card_data != card_base && card_data != (card_data_end - 1))
2755 sgen_card_table_prepare_card_for_scanning (card_data);
2757 card_end = MIN (card_end, obj_end);
2759 if (elem < (char*)start_root)
2760 first_elem = elem = (char*)start_root;
2762 for (; elem < card_end; elem += SIZEOF_VOID_P) {
2763 if (*(GCObject**)elem)
2764 scan_field_func (NULL, (GCObject**)elem, ctx.queue);
2767 binary_protocol_card_scan (first_elem, elem - first_elem);
2770 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2771 if (overflow_scan_end) {
2772 extra_idx = card_data - card_base;
2773 card_base = card_data = sgen_shadow_cardtable;
2774 card_data_end = overflow_scan_end;
2775 overflow_scan_end = NULL;
2782 sgen_wbroots_scan_card_table (ScanCopyContext ctx)
2787 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_WBARRIER], void **, start_root, RootRecord *, root) {
2788 SGEN_ASSERT (0, (root->root_desc & ROOT_DESC_TYPE_MASK) == ROOT_DESC_VECTOR, "Unsupported root type");
2790 sgen_wbroot_scan_card_table (start_root, (mword)root->end_root - (mword)start_root, ctx);
2791 } SGEN_HASH_TABLE_FOREACH_END;
2795 * ######################################################################
2796 * ######## Thread handling (stop/start code)
2797 * ######################################################################
2801 sgen_get_current_collection_generation (void)
2803 return current_collection_generation;
2807 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2809 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2811 sgen_client_thread_register (info, stack_bottom_fallback);
2817 sgen_thread_unregister (SgenThreadInfo *p)
2819 sgen_client_thread_unregister (p);
2823 * ######################################################################
2824 * ######## Write barriers
2825 * ######################################################################
2829 * Note: the write barriers first do the needed GC work and then do the actual store:
2830 * this way the value is visible to the conservative GC scan after the write barrier
2831 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2832 * the conservative scan, otherwise by the remembered set scan.
2836 * mono_gc_wbarrier_arrayref_copy:
2839 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2841 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2842 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2843 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2844 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2848 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2849 if (binary_protocol_is_heavy_enabled ()) {
2851 for (i = 0; i < count; ++i) {
2852 gpointer dest = (gpointer*)dest_ptr + i;
2853 gpointer obj = *((gpointer*)src_ptr + i);
2855 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2860 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2864 * mono_gc_wbarrier_generic_nostore:
2867 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2871 HEAVY_STAT (++stat_wbarrier_generic_store);
2873 sgen_client_wbarrier_generic_nostore_check (ptr);
2875 obj = *(gpointer*)ptr;
2877 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2880 * We need to record old->old pointer locations for the
2881 * concurrent collector.
2883 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2884 SGEN_LOG (8, "Skipping remset at %p", ptr);
2888 SGEN_LOG (8, "Adding remset at %p", ptr);
2890 remset.wbarrier_generic_nostore (ptr);
2894 * mono_gc_wbarrier_generic_store:
2897 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2899 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2900 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2901 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2902 mono_gc_wbarrier_generic_nostore (ptr);
2903 sgen_dummy_use (value);
2907 * mono_gc_wbarrier_generic_store_atomic:
2908 * Same as \c mono_gc_wbarrier_generic_store but performs the store
2909 * as an atomic operation with release semantics.
2912 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2914 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2916 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2918 InterlockedWritePointer ((volatile gpointer *)ptr, value);
2920 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2921 mono_gc_wbarrier_generic_nostore (ptr);
2923 sgen_dummy_use (value);
2927 sgen_wbarrier_range_copy (gpointer _dest, gpointer _src, int size)
2929 remset.wbarrier_range_copy (_dest,_src, size);
2933 * ######################################################################
2934 * ######## Other mono public interface functions.
2935 * ######################################################################
2939 sgen_gc_collect (int generation)
2944 sgen_perform_collection (0, generation, "user request", TRUE, TRUE);
2949 sgen_gc_collection_count (int generation)
2951 if (generation == 0)
2952 return gc_stats.minor_gc_count;
2953 return gc_stats.major_gc_count;
2957 sgen_gc_get_used_size (void)
2961 tot = los_memory_usage;
2962 tot += nursery_section->end_data - nursery_section->data;
2963 tot += major_collector.get_used_size ();
2964 /* FIXME: account for pinned objects */
2970 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2974 va_start (ap, description_format);
2976 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2977 vfprintf (stderr, description_format, ap);
2979 fprintf (stderr, " - %s", fallback);
2980 fprintf (stderr, "\n");
2986 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2989 double val = strtod (opt, &endptr);
2990 if (endptr == opt) {
2991 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2994 else if (val < min || val > max) {
2995 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
3007 char *major_collector_opt = NULL;
3008 char *minor_collector_opt = NULL;
3009 char *params_opts = NULL;
3010 char *debug_opts = NULL;
3011 size_t max_heap = 0;
3012 size_t soft_limit = 0;
3014 gboolean debug_print_allowance = FALSE;
3015 double allowance_ratio = 0, save_target = 0;
3016 gboolean cement_enabled = TRUE;
3017 gboolean dynamic_nursery = FALSE;
3018 size_t min_nursery_size = 0, max_nursery_size = 0;
3021 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
3024 /* already inited */
3027 /* being inited by another thread */
3028 mono_thread_info_usleep (1000);
3031 /* we will init it */
3034 g_assert_not_reached ();
3036 } while (result != 0);
3038 SGEN_TV_GETTIME (sgen_init_timestamp);
3040 #ifdef SGEN_WITHOUT_MONO
3041 mono_thread_smr_init ();
3044 mono_coop_mutex_init (&gc_mutex);
3046 gc_debug_file = stderr;
3048 mono_coop_mutex_init (&sgen_interruption_mutex);
3050 if ((env = g_getenv (MONO_GC_PARAMS_NAME)) || gc_params_options) {
3051 params_opts = g_strdup_printf ("%s,%s", gc_params_options ? gc_params_options : "", env ? env : "");
3056 opts = g_strsplit (params_opts, ",", -1);
3057 for (ptr = opts; *ptr; ++ptr) {
3059 if (g_str_has_prefix (opt, "major=")) {
3060 opt = strchr (opt, '=') + 1;
3061 major_collector_opt = g_strdup (opt);
3062 } else if (g_str_has_prefix (opt, "minor=")) {
3063 opt = strchr (opt, '=') + 1;
3064 minor_collector_opt = g_strdup (opt);
3072 sgen_init_internal_allocator ();
3073 sgen_init_nursery_allocator ();
3074 sgen_init_fin_weak_hash ();
3075 sgen_init_hash_table ();
3076 sgen_init_descriptors ();
3077 sgen_init_gray_queues ();
3078 sgen_init_allocator ();
3079 sgen_init_gchandles ();
3081 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
3082 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
3084 sgen_client_init ();
3086 if (!minor_collector_opt) {
3087 sgen_simple_nursery_init (&sgen_minor_collector, FALSE);
3089 if (!strcmp (minor_collector_opt, "simple")) {
3091 sgen_simple_nursery_init (&sgen_minor_collector, FALSE);
3092 } else if (!strcmp (minor_collector_opt, "simple-par")) {
3093 sgen_simple_nursery_init (&sgen_minor_collector, TRUE);
3094 } else if (!strcmp (minor_collector_opt, "split")) {
3095 sgen_split_nursery_init (&sgen_minor_collector);
3097 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
3098 goto use_simple_nursery;
3102 if (!major_collector_opt) {
3104 DEFAULT_MAJOR_INIT (&major_collector);
3105 } else if (!strcmp (major_collector_opt, "marksweep")) {
3106 sgen_marksweep_init (&major_collector);
3107 } else if (!strcmp (major_collector_opt, "marksweep-conc")) {
3108 sgen_marksweep_conc_init (&major_collector);
3109 } else if (!strcmp (major_collector_opt, "marksweep-conc-par")) {
3110 sgen_marksweep_conc_par_init (&major_collector);
3112 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `" DEFAULT_MAJOR_NAME "` instead.", "Unknown major collector `%s'.", major_collector_opt);
3113 goto use_default_major;
3117 gboolean usage_printed = FALSE;
3119 for (ptr = opts; *ptr; ++ptr) {
3121 if (!strcmp (opt, ""))
3123 if (g_str_has_prefix (opt, "major="))
3125 if (g_str_has_prefix (opt, "minor="))
3127 if (g_str_has_prefix (opt, "max-heap-size=")) {
3128 size_t page_size = mono_pagesize ();
3129 size_t max_heap_candidate = 0;
3130 opt = strchr (opt, '=') + 1;
3131 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
3132 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
3133 if (max_heap != max_heap_candidate)
3134 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
3136 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
3140 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
3141 opt = strchr (opt, '=') + 1;
3142 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
3143 if (soft_limit <= 0) {
3144 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
3148 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
3152 if (g_str_has_prefix (opt, "nursery-size=")) {
3154 opt = strchr (opt, '=') + 1;
3155 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
3156 if ((val & (val - 1))) {
3157 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
3161 if (val < SGEN_MAX_NURSERY_WASTE) {
3162 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3163 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
3167 min_nursery_size = max_nursery_size = val;
3168 dynamic_nursery = FALSE;
3170 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
3175 if (g_str_has_prefix (opt, "save-target-ratio=")) {
3177 opt = strchr (opt, '=') + 1;
3178 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
3179 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
3184 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
3186 opt = strchr (opt, '=') + 1;
3187 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
3188 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3189 allowance_ratio = val;
3194 if (!strcmp (opt, "cementing")) {
3195 cement_enabled = TRUE;
3198 if (!strcmp (opt, "no-cementing")) {
3199 cement_enabled = FALSE;
3203 if (!strcmp (opt, "precleaning")) {
3204 precleaning_enabled = TRUE;
3207 if (!strcmp (opt, "no-precleaning")) {
3208 precleaning_enabled = FALSE;
3212 if (!strcmp (opt, "dynamic-nursery")) {
3213 if (sgen_minor_collector.is_split)
3214 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3215 "dynamic-nursery not supported with split-nursery.");
3217 dynamic_nursery = TRUE;
3220 if (!strcmp (opt, "no-dynamic-nursery")) {
3221 dynamic_nursery = FALSE;
3225 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3228 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3231 if (sgen_client_handle_gc_param (opt))
3234 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3239 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3240 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3241 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3242 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3243 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3244 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3245 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3246 fprintf (stderr, " [no-]cementing\n");
3247 fprintf (stderr, " [no-]dynamic-nursery\n");
3248 if (major_collector.print_gc_param_usage)
3249 major_collector.print_gc_param_usage ();
3250 if (sgen_minor_collector.print_gc_param_usage)
3251 sgen_minor_collector.print_gc_param_usage ();
3252 sgen_client_print_gc_params_usage ();
3253 fprintf (stderr, " Experimental options:\n");
3254 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3255 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);
3256 fprintf (stderr, "\n");
3258 usage_printed = TRUE;
3263 if (major_collector_opt)
3264 g_free (major_collector_opt);
3266 if (minor_collector_opt)
3267 g_free (minor_collector_opt);
3270 g_free (params_opts);
3272 alloc_nursery (dynamic_nursery, min_nursery_size, max_nursery_size);
3274 sgen_pinning_init ();
3275 sgen_cement_init (cement_enabled);
3277 if ((env = g_getenv (MONO_GC_DEBUG_NAME)) || gc_debug_options) {
3278 debug_opts = g_strdup_printf ("%s,%s", gc_debug_options ? gc_debug_options : "", env ? env : "");
3283 gboolean usage_printed = FALSE;
3285 opts = g_strsplit (debug_opts, ",", -1);
3286 for (ptr = opts; ptr && *ptr; ptr ++) {
3288 if (!strcmp (opt, ""))
3290 if (opt [0] >= '0' && opt [0] <= '9') {
3291 gc_debug_level = atoi (opt);
3296 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3297 gc_debug_file = fopen (rf, "wb");
3299 gc_debug_file = stderr;
3302 } else if (!strcmp (opt, "print-allowance")) {
3303 debug_print_allowance = TRUE;
3304 } else if (!strcmp (opt, "print-pinning")) {
3305 sgen_pin_stats_enable ();
3306 } else if (!strcmp (opt, "verify-before-allocs")) {
3307 verify_before_allocs = 1;
3308 has_per_allocation_action = TRUE;
3309 } else if (g_str_has_prefix (opt, "max-valloc-size=")) {
3310 size_t max_valloc_size;
3311 char *arg = strchr (opt, '=') + 1;
3312 if (*opt && mono_gc_parse_environment_string_extract_number (arg, &max_valloc_size)) {
3313 mono_valloc_set_limit (max_valloc_size);
3315 sgen_env_var_error (MONO_GC_DEBUG_NAME, NULL, "`max-valloc-size` must be an integer.");
3318 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3319 char *arg = strchr (opt, '=') + 1;
3320 verify_before_allocs = atoi (arg);
3321 has_per_allocation_action = TRUE;
3322 } else if (!strcmp (opt, "collect-before-allocs")) {
3323 collect_before_allocs = 1;
3324 has_per_allocation_action = TRUE;
3325 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3326 char *arg = strchr (opt, '=') + 1;
3327 has_per_allocation_action = TRUE;
3328 collect_before_allocs = atoi (arg);
3329 } else if (!strcmp (opt, "verify-before-collections")) {
3330 whole_heap_check_before_collection = TRUE;
3331 } else if (!strcmp (opt, "check-remset-consistency")) {
3332 remset_consistency_checks = TRUE;
3333 nursery_clear_policy = CLEAR_AT_GC;
3334 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3335 if (!major_collector.is_concurrent) {
3336 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3339 mod_union_consistency_check = TRUE;
3340 } else if (!strcmp (opt, "check-mark-bits")) {
3341 check_mark_bits_after_major_collection = TRUE;
3342 } else if (!strcmp (opt, "check-nursery-pinned")) {
3343 check_nursery_objects_pinned = TRUE;
3344 } else if (!strcmp (opt, "clear-at-gc")) {
3345 nursery_clear_policy = CLEAR_AT_GC;
3346 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3347 nursery_clear_policy = CLEAR_AT_GC;
3348 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3349 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3350 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3351 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3352 } else if (!strcmp (opt, "check-scan-starts")) {
3353 do_scan_starts_check = TRUE;
3354 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3355 do_verify_nursery = TRUE;
3356 } else if (!strcmp (opt, "check-concurrent")) {
3357 if (!major_collector.is_concurrent) {
3358 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3361 nursery_clear_policy = CLEAR_AT_GC;
3362 do_concurrent_checks = TRUE;
3363 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3364 do_dump_nursery_content = TRUE;
3365 } else if (!strcmp (opt, "disable-minor")) {
3366 disable_minor_collections = TRUE;
3367 } else if (!strcmp (opt, "disable-major")) {
3368 disable_major_collections = TRUE;
3369 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3370 char *filename = strchr (opt, '=') + 1;
3371 nursery_clear_policy = CLEAR_AT_GC;
3372 sgen_debug_enable_heap_dump (filename);
3373 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3374 char *filename = strchr (opt, '=') + 1;
3375 char *colon = strrchr (filename, ':');
3378 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3379 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3384 binary_protocol_init (filename, (long long)limit);
3385 } else if (!strcmp (opt, "nursery-canaries")) {
3386 do_verify_nursery = TRUE;
3387 enable_nursery_canaries = TRUE;
3388 } else if (!sgen_client_handle_gc_debug (opt)) {
3389 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3394 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);
3395 fprintf (stderr, "Valid <option>s are:\n");
3396 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3397 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3398 fprintf (stderr, " max-valloc-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3399 fprintf (stderr, " check-remset-consistency\n");
3400 fprintf (stderr, " check-mark-bits\n");
3401 fprintf (stderr, " check-nursery-pinned\n");
3402 fprintf (stderr, " verify-before-collections\n");
3403 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3404 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3405 fprintf (stderr, " disable-minor\n");
3406 fprintf (stderr, " disable-major\n");
3407 fprintf (stderr, " check-concurrent\n");
3408 fprintf (stderr, " clear-[nursery-]at-gc\n");
3409 fprintf (stderr, " clear-at-tlab-creation\n");
3410 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3411 fprintf (stderr, " check-scan-starts\n");
3412 fprintf (stderr, " print-allowance\n");
3413 fprintf (stderr, " print-pinning\n");
3414 fprintf (stderr, " heap-dump=<filename>\n");
3415 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3416 fprintf (stderr, " nursery-canaries\n");
3417 sgen_client_print_gc_debug_usage ();
3418 fprintf (stderr, "\n");
3420 usage_printed = TRUE;
3427 g_free (debug_opts);
3429 if (check_mark_bits_after_major_collection)
3430 nursery_clear_policy = CLEAR_AT_GC;
3432 if (major_collector.post_param_init)
3433 major_collector.post_param_init (&major_collector);
3435 if (major_collector.is_concurrent || sgen_minor_collector.is_parallel) {
3436 int num_workers = 1;
3437 if (major_collector.is_parallel || sgen_minor_collector.is_parallel) {
3438 num_workers = mono_cpu_count ();
3439 if (num_workers < 1)
3442 sgen_workers_init (num_workers, (SgenWorkerCallback) major_collector.worker_init_cb);
3445 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3447 memset (&remset, 0, sizeof (remset));
3449 sgen_card_table_init (&remset);
3451 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");
3455 sgen_init_bridge ();
3459 sgen_gc_initialized ()
3461 return gc_initialized > 0;
3465 sgen_get_nursery_clear_policy (void)
3467 return nursery_clear_policy;
3473 mono_coop_mutex_lock (&gc_mutex);
3477 sgen_gc_unlock (void)
3479 mono_coop_mutex_unlock (&gc_mutex);
3483 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3485 major_collector.iterate_live_block_ranges (callback);
3489 sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback)
3491 major_collector.iterate_block_ranges (callback);
3495 sgen_get_major_collector (void)
3497 return &major_collector;
3501 sgen_get_minor_collector (void)
3503 return &sgen_minor_collector;
3507 sgen_get_remset (void)
3513 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3515 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3516 sgen_los_count_cards (los_total, los_marked);
3519 static gboolean world_is_stopped = FALSE;
3521 /* LOCKING: assumes the GC lock is held */
3523 sgen_stop_world (int generation)
3525 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3527 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3529 binary_protocol_world_stopping (generation, sgen_timestamp (), (gpointer) (gsize) mono_native_thread_id_get ());
3531 sgen_client_stop_world (generation);
3533 world_is_stopped = TRUE;
3535 if (binary_protocol_is_heavy_enabled ())
3536 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3537 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3540 /* LOCKING: assumes the GC lock is held */
3542 sgen_restart_world (int generation)
3544 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3547 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3549 if (binary_protocol_is_heavy_enabled ())
3550 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3551 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3553 world_is_stopped = FALSE;
3555 sgen_client_restart_world (generation, &stw_time);
3557 binary_protocol_world_restarted (generation, sgen_timestamp ());
3559 if (sgen_client_bridge_need_processing ())
3560 sgen_client_bridge_processing_finish (generation);
3562 sgen_memgov_collection_end (generation, stw_time);
3566 sgen_is_world_stopped (void)
3568 return world_is_stopped;
3572 sgen_check_whole_heap_stw (void)
3574 sgen_stop_world (0);
3575 sgen_clear_nursery_fragments ();
3576 sgen_check_whole_heap (TRUE);
3577 sgen_restart_world (0);
3581 sgen_timestamp (void)
3583 SGEN_TV_DECLARE (timestamp);
3584 SGEN_TV_GETTIME (timestamp);
3585 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3588 #endif /* HAVE_SGEN_GC */