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>
197 #undef pthread_create
199 #undef pthread_detach
202 * ######################################################################
203 * ######## Types and constants used by the GC.
204 * ######################################################################
207 /* 0 means not initialized, 1 is initialized, -1 means in progress */
208 static int gc_initialized = 0;
209 /* If set, check if we need to do something every X allocations */
210 gboolean has_per_allocation_action;
211 /* If set, do a heap check every X allocation */
212 guint32 verify_before_allocs = 0;
213 /* If set, do a minor collection before every X allocation */
214 guint32 collect_before_allocs = 0;
215 /* If set, do a whole heap check before each collection */
216 static gboolean whole_heap_check_before_collection = FALSE;
217 /* If set, do a remset consistency check at various opportunities */
218 static gboolean remset_consistency_checks = FALSE;
219 /* If set, do a mod union consistency check before each finishing collection pause */
220 static gboolean mod_union_consistency_check = FALSE;
221 /* If set, check whether mark bits are consistent after major collections */
222 static gboolean check_mark_bits_after_major_collection = FALSE;
223 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
224 static gboolean check_nursery_objects_pinned = FALSE;
225 /* If set, do a few checks when the concurrent collector is used */
226 static gboolean do_concurrent_checks = FALSE;
227 /* If set, do a plausibility check on the scan_starts before and after
229 static gboolean do_scan_starts_check = FALSE;
231 static gboolean disable_minor_collections = FALSE;
232 static gboolean disable_major_collections = FALSE;
233 static gboolean do_verify_nursery = FALSE;
234 static gboolean do_dump_nursery_content = FALSE;
235 static gboolean enable_nursery_canaries = FALSE;
237 static gboolean precleaning_enabled = TRUE;
239 #ifdef HEAVY_STATISTICS
240 guint64 stat_objects_alloced_degraded = 0;
241 guint64 stat_bytes_alloced_degraded = 0;
243 guint64 stat_copy_object_called_nursery = 0;
244 guint64 stat_objects_copied_nursery = 0;
245 guint64 stat_copy_object_called_major = 0;
246 guint64 stat_objects_copied_major = 0;
248 guint64 stat_scan_object_called_nursery = 0;
249 guint64 stat_scan_object_called_major = 0;
251 guint64 stat_slots_allocated_in_vain;
253 guint64 stat_nursery_copy_object_failed_from_space = 0;
254 guint64 stat_nursery_copy_object_failed_forwarded = 0;
255 guint64 stat_nursery_copy_object_failed_pinned = 0;
256 guint64 stat_nursery_copy_object_failed_to_space = 0;
258 static guint64 stat_wbarrier_add_to_global_remset = 0;
259 static guint64 stat_wbarrier_arrayref_copy = 0;
260 static guint64 stat_wbarrier_generic_store = 0;
261 static guint64 stat_wbarrier_generic_store_atomic = 0;
262 static guint64 stat_wbarrier_set_root = 0;
265 static guint64 stat_pinned_objects = 0;
267 static guint64 time_minor_pre_collection_fragment_clear = 0;
268 static guint64 time_minor_pinning = 0;
269 static guint64 time_minor_scan_remsets = 0;
270 static guint64 time_minor_scan_major_blocks = 0;
271 static guint64 time_minor_scan_los = 0;
272 static guint64 time_minor_scan_pinned = 0;
273 static guint64 time_minor_scan_roots = 0;
274 static guint64 time_minor_finish_gray_stack = 0;
275 static guint64 time_minor_fragment_creation = 0;
277 static guint64 time_major_pre_collection_fragment_clear = 0;
278 static guint64 time_major_pinning = 0;
279 static guint64 time_major_scan_pinned = 0;
280 static guint64 time_major_scan_roots = 0;
281 static guint64 time_major_scan_mod_union = 0;
282 static guint64 time_major_finish_gray_stack = 0;
283 static guint64 time_major_free_bigobjs = 0;
284 static guint64 time_major_los_sweep = 0;
285 static guint64 time_major_sweep = 0;
286 static guint64 time_major_fragment_creation = 0;
288 static guint64 time_max = 0;
290 static SGEN_TV_DECLARE (time_major_conc_collection_start);
291 static SGEN_TV_DECLARE (time_major_conc_collection_end);
293 int gc_debug_level = 0;
295 static char* gc_params_options;
296 static char* gc_debug_options;
300 mono_gc_flush_info (void)
302 fflush (gc_debug_file);
306 #define TV_DECLARE SGEN_TV_DECLARE
307 #define TV_GETTIME SGEN_TV_GETTIME
308 #define TV_ELAPSED SGEN_TV_ELAPSED
310 static SGEN_TV_DECLARE (sgen_init_timestamp);
312 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
314 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
315 #define object_is_pinned SGEN_OBJECT_IS_PINNED
316 #define pin_object SGEN_PIN_OBJECT
318 #define ptr_in_nursery sgen_ptr_in_nursery
320 #define LOAD_VTABLE SGEN_LOAD_VTABLE
323 nursery_canaries_enabled (void)
325 return enable_nursery_canaries;
328 #define safe_object_get_size sgen_safe_object_get_size
330 #if defined(HAVE_CONC_GC_AS_DEFAULT)
331 /* Use concurrent major on deskstop platforms */
332 #define DEFAULT_MAJOR_INIT sgen_marksweep_conc_init
333 #define DEFAULT_MAJOR_NAME "marksweep-conc"
335 #define DEFAULT_MAJOR_INIT sgen_marksweep_init
336 #define DEFAULT_MAJOR_NAME "marksweep"
340 * ######################################################################
341 * ######## Global data.
342 * ######################################################################
344 MonoCoopMutex gc_mutex;
346 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
348 size_t degraded_mode = 0;
350 static mword bytes_pinned_from_failed_allocation = 0;
352 GCMemSection *nursery_section = NULL;
353 static volatile mword lowest_heap_address = ~(mword)0;
354 static volatile mword highest_heap_address = 0;
356 MonoCoopMutex sgen_interruption_mutex;
358 int current_collection_generation = -1;
359 static volatile gboolean concurrent_collection_in_progress = FALSE;
361 /* objects that are ready to be finalized */
362 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
363 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
365 /* registered roots: the key to the hash is the root start address */
367 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
369 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
370 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
371 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
372 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
374 static mword roots_size = 0; /* amount of memory in the root set */
376 /* The size of a TLAB */
377 /* The bigger the value, the less often we have to go to the slow path to allocate a new
378 * one, but the more space is wasted by threads not allocating much memory.
380 * FIXME: Make this self-tuning for each thread.
382 guint32 tlab_size = (1024 * 4);
384 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
386 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
388 #define ALIGN_UP SGEN_ALIGN_UP
390 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
391 MonoNativeThreadId main_gc_thread = NULL;
394 /*Object was pinned during the current collection*/
395 static mword objects_pinned;
398 * ######################################################################
399 * ######## Macros and function declarations.
400 * ######################################################################
403 /* forward declarations */
404 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
406 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
407 static void finish_gray_stack (int generation, ScanCopyContext ctx);
410 SgenMajorCollector major_collector;
411 SgenMinorCollector sgen_minor_collector;
413 static SgenRememberedSet remset;
416 * The gray queue a worker job must use. If we're not parallel or
417 * concurrent, we use the main gray queue.
419 static SgenGrayQueue*
420 sgen_workers_get_job_gray_queue (WorkerData *worker_data, SgenGrayQueue *default_gray_queue)
423 return &worker_data->private_gray_queue;
424 SGEN_ASSERT (0, default_gray_queue, "Why don't we have a default gray queue when we're not running in a worker thread?");
425 return default_gray_queue;
429 gray_queue_redirect (SgenGrayQueue *queue)
431 sgen_workers_take_from_queue (queue);
435 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries)
437 while (start < end) {
441 if (!*(void**)start) {
442 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
447 if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
453 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
454 CHECK_CANARY_FOR_OBJECT ((GCObject*)obj, fail_on_canaries);
455 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
456 callback ((GCObject*)obj, size, data);
457 CANARIFY_SIZE (size);
459 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
467 * sgen_add_to_global_remset:
469 * The global remset contains locations which point into newspace after
470 * a minor collection. This can happen if the objects they point to are pinned.
472 * LOCKING: If called from a parallel collector, the global remset
473 * lock must be held. For serial collectors that is not necessary.
476 sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
478 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
480 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
482 if (!major_collector.is_concurrent) {
483 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
485 if (current_collection_generation == -1)
486 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
489 if (!object_is_pinned (obj))
490 SGEN_ASSERT (5, sgen_minor_collector.is_split || sgen_concurrent_collection_in_progress (), "Non-pinned objects can only remain in nursery if it is a split nursery");
491 else if (sgen_cement_lookup_or_register (obj))
494 remset.record_pointer (ptr);
496 sgen_pin_stats_register_global_remset (obj);
498 SGEN_LOG (8, "Adding global remset for %p", ptr);
499 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
503 * sgen_drain_gray_stack:
505 * Scan objects in the gray stack until the stack is empty. This should be called
506 * frequently after each object is copied, to achieve better locality and cache
511 sgen_drain_gray_stack (ScanCopyContext ctx)
513 SGEN_ASSERT (0, ctx.ops->drain_gray_stack, "Why do we have a scan/copy context with a missing drain gray stack function?");
515 return ctx.ops->drain_gray_stack (ctx.queue);
519 * Addresses in the pin queue are already sorted. This function finds
520 * the object header for each address and pins the object. The
521 * addresses must be inside the nursery section. The (start of the)
522 * address array is overwritten with the addresses of the actually
523 * pinned objects. Return the number of pinned objects.
526 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
528 GCMemSection *section = nursery_section;
529 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
530 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
531 void *start_nursery = section->data;
532 void *end_nursery = section->next_data;
537 void *pinning_front = start_nursery;
539 void **definitely_pinned = start;
540 ScanObjectFunc scan_func = ctx.ops->scan_object;
541 SgenGrayQueue *queue = ctx.queue;
543 sgen_nursery_allocator_prepare_for_pinning ();
545 while (start < end) {
546 GCObject *obj_to_pin = NULL;
547 size_t obj_to_pin_size = 0;
552 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
553 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
560 SGEN_LOG (5, "Considering pinning addr %p", addr);
561 /* We've already processed everything up to pinning_front. */
562 if (addr < pinning_front) {
568 * Find the closest scan start <= addr. We might search backward in the
569 * scan_starts array because entries might be NULL. In the worst case we
570 * start at start_nursery.
572 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
573 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
574 search_start = (void*)section->scan_starts [idx];
575 if (!search_start || search_start > addr) {
578 search_start = section->scan_starts [idx];
579 if (search_start && search_start <= addr)
582 if (!search_start || search_start > addr)
583 search_start = start_nursery;
587 * If the pinning front is closer than the scan start we found, start
588 * searching at the front.
590 if (search_start < pinning_front)
591 search_start = pinning_front;
594 * Now addr should be in an object a short distance from search_start.
596 * search_start must point to zeroed mem or point to an object.
599 size_t obj_size, canarified_obj_size;
602 if (!*(void**)search_start) {
603 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
604 /* The loop condition makes sure we don't overrun addr. */
608 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
611 * Filler arrays are marked by an invalid sync word. We don't
612 * consider them for pinning. They are not delimited by canaries,
615 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
616 CHECK_CANARY_FOR_OBJECT (search_start, TRUE);
617 CANARIFY_SIZE (canarified_obj_size);
619 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
620 /* This is the object we're looking for. */
621 obj_to_pin = (GCObject*)search_start;
622 obj_to_pin_size = canarified_obj_size;
627 /* Skip to the next object */
628 search_start = (void*)((char*)search_start + canarified_obj_size);
629 } while (search_start <= addr);
631 /* We've searched past the address we were looking for. */
633 pinning_front = search_start;
634 goto next_pin_queue_entry;
638 * We've found an object to pin. It might still be a dummy array, but we
639 * can advance the pinning front in any case.
641 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
644 * If this is a dummy array marking the beginning of a nursery
645 * fragment, we don't pin it.
647 if (sgen_client_object_is_array_fill (obj_to_pin))
648 goto next_pin_queue_entry;
651 * Finally - pin the object!
653 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
654 if (do_scan_objects) {
655 scan_func (obj_to_pin, desc, queue);
657 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
658 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
659 binary_protocol_pin (obj_to_pin,
660 (gpointer)LOAD_VTABLE (obj_to_pin),
661 safe_object_get_size (obj_to_pin));
663 pin_object (obj_to_pin);
664 GRAY_OBJECT_ENQUEUE_SERIAL (queue, obj_to_pin, desc);
665 sgen_pin_stats_register_object (obj_to_pin, GENERATION_NURSERY);
666 definitely_pinned [count] = obj_to_pin;
669 if (concurrent_collection_in_progress)
670 sgen_pinning_register_pinned_in_nursery (obj_to_pin);
672 next_pin_queue_entry:
676 sgen_client_nursery_objects_pinned (definitely_pinned, count);
677 stat_pinned_objects += count;
682 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
686 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
689 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
690 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
694 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
695 * when we can't promote an object because we're out of memory.
698 sgen_pin_object (GCObject *object, SgenGrayQueue *queue)
700 SGEN_ASSERT (0, sgen_ptr_in_nursery (object), "We're only supposed to use this for pinning nursery objects when out of memory.");
703 * All pinned objects are assumed to have been staged, so we need to stage as well.
704 * Also, the count of staged objects shows that "late pinning" happened.
706 sgen_pin_stage_ptr (object);
708 SGEN_PIN_OBJECT (object);
709 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
712 sgen_pin_stats_register_object (object, GENERATION_NURSERY);
714 GRAY_OBJECT_ENQUEUE_SERIAL (queue, object, sgen_obj_get_descriptor_safe (object));
717 /* Sort the addresses in array in increasing order.
718 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
721 sgen_sort_addresses (void **array, size_t size)
726 for (i = 1; i < size; ++i) {
729 size_t parent = (child - 1) / 2;
731 if (array [parent] >= array [child])
734 tmp = array [parent];
735 array [parent] = array [child];
742 for (i = size - 1; i > 0; --i) {
745 array [i] = array [0];
751 while (root * 2 + 1 <= end) {
752 size_t child = root * 2 + 1;
754 if (child < end && array [child] < array [child + 1])
756 if (array [root] >= array [child])
760 array [root] = array [child];
769 * Scan the memory between start and end and queue values which could be pointers
770 * to the area between start_nursery and end_nursery for later consideration.
771 * Typically used for thread stacks.
774 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
778 SGEN_ASSERT (0, ((mword)start & (SIZEOF_VOID_P - 1)) == 0, "Why are we scanning for references in unaligned memory ?");
780 #if defined(VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE) && !defined(_WIN64)
781 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
784 while (start < end) {
786 * *start can point to the middle of an object
787 * note: should we handle pointing at the end of an object?
788 * pinning in C# code disallows pointing at the end of an object
789 * but there is some small chance that an optimizing C compiler
790 * may keep the only reference to an object by pointing
791 * at the end of it. We ignore this small chance for now.
792 * Pointers to the end of an object are indistinguishable
793 * from pointers to the start of the next object in memory
794 * so if we allow that we'd need to pin two objects...
795 * We queue the pointer in an array, the
796 * array will then be sorted and uniqued. This way
797 * we can coalesce several pinning pointers and it should
798 * be faster since we'd do a memory scan with increasing
799 * addresses. Note: we can align the address to the allocation
800 * alignment, so the unique process is more effective.
802 mword addr = (mword)*start;
803 addr &= ~(ALLOC_ALIGN - 1);
804 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
805 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
806 sgen_pin_stage_ptr ((void*)addr);
807 binary_protocol_pin_stage (start, (void*)addr);
808 sgen_pin_stats_register_address ((char*)addr, pin_type);
814 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
818 * The first thing we do in a collection is to identify pinned objects.
819 * This function considers all the areas of memory that need to be
820 * conservatively scanned.
823 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
827 SGEN_LOG (2, "Scanning pinned roots (%d bytes, %d/%d entries)", (int)roots_size, roots_hash [ROOT_TYPE_NORMAL].num_entries, roots_hash [ROOT_TYPE_PINNED].num_entries);
828 /* objects pinned from the API are inside these roots */
829 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
830 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
831 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
832 } SGEN_HASH_TABLE_FOREACH_END;
833 /* now deal with the thread stacks
834 * in the future we should be able to conservatively scan only:
835 * *) the cpu registers
836 * *) the unmanaged stack frames
837 * *) the _last_ managed stack frame
838 * *) pointers slots in managed frames
840 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
844 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
846 ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
847 ctx->ops->copy_or_mark_object (obj, ctx->queue);
851 * The memory area from start_root to end_root contains pointers to objects.
852 * Their position is precisely described by @desc (this means that the pointer
853 * can be either NULL or the pointer to the start of an object).
854 * This functions copies them to to_space updates them.
856 * This function is not thread-safe!
859 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, SgenDescriptor desc, ScanCopyContext ctx)
861 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
862 ScanPtrFieldFunc scan_field_func = ctx.ops->scan_ptr_field;
863 SgenGrayQueue *queue = ctx.queue;
865 switch (desc & ROOT_DESC_TYPE_MASK) {
866 case ROOT_DESC_BITMAP:
867 desc >>= ROOT_DESC_TYPE_SHIFT;
869 if ((desc & 1) && *start_root) {
870 copy_func ((GCObject**)start_root, queue);
871 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
877 case ROOT_DESC_COMPLEX: {
878 gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
879 gsize bwords = (*bitmap_data) - 1;
880 void **start_run = start_root;
882 while (bwords-- > 0) {
883 gsize bmap = *bitmap_data++;
884 void **objptr = start_run;
886 if ((bmap & 1) && *objptr) {
887 copy_func ((GCObject**)objptr, queue);
888 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
893 start_run += GC_BITS_PER_WORD;
897 case ROOT_DESC_VECTOR: {
900 for (p = start_root; p < end_root; p++) {
902 scan_field_func (NULL, (GCObject**)p, queue);
906 case ROOT_DESC_USER: {
907 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
908 marker (start_root, single_arg_user_copy_or_mark, &ctx);
911 case ROOT_DESC_RUN_LEN:
912 g_assert_not_reached ();
914 g_assert_not_reached ();
919 reset_heap_boundaries (void)
921 lowest_heap_address = ~(mword)0;
922 highest_heap_address = 0;
926 sgen_update_heap_boundaries (mword low, mword high)
931 old = lowest_heap_address;
934 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
937 old = highest_heap_address;
940 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
944 * Allocate and setup the data structures needed to be able to allocate objects
945 * in the nursery. The nursery is stored in nursery_section.
950 GCMemSection *section;
957 SGEN_LOG (2, "Allocating nursery size: %zu", (size_t)sgen_nursery_size);
958 /* later we will alloc a larger area for the nursery but only activate
959 * what we need. The rest will be used as expansion if we have too many pinned
960 * objects in the existing nursery.
962 /* FIXME: handle OOM */
963 section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
965 alloc_size = sgen_nursery_size;
967 /* If there isn't enough space even for the nursery we should simply abort. */
968 g_assert (sgen_memgov_try_alloc_space (alloc_size, SPACE_NURSERY));
970 data = (char *)major_collector.alloc_heap (alloc_size, alloc_size, DEFAULT_NURSERY_BITS);
971 sgen_update_heap_boundaries ((mword)data, (mword)(data + sgen_nursery_size));
972 SGEN_LOG (4, "Expanding nursery size (%p-%p): %lu, total: %lu", data, data + alloc_size, (unsigned long)sgen_nursery_size, (unsigned long)sgen_gc_get_total_heap_allocation ());
973 section->data = section->next_data = data;
974 section->size = alloc_size;
975 section->end_data = data + sgen_nursery_size;
976 scan_starts = (alloc_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
977 section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
978 section->num_scan_start = scan_starts;
980 nursery_section = section;
982 sgen_nursery_allocator_set_nursery_bounds (data, data + sgen_nursery_size);
986 mono_gc_get_logfile (void)
988 return gc_debug_file;
992 mono_gc_params_set (const char* options)
994 if (gc_params_options)
995 g_free (gc_params_options);
997 gc_params_options = g_strdup (options);
1001 mono_gc_debug_set (const char* options)
1003 if (gc_debug_options)
1004 g_free (gc_debug_options);
1006 gc_debug_options = g_strdup (options);
1010 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1012 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1013 SgenGrayQueue *queue = ctx.queue;
1016 for (i = 0; i < fin_queue->next_slot; ++i) {
1017 GCObject *obj = (GCObject *)fin_queue->data [i];
1020 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1021 copy_func ((GCObject**)&fin_queue->data [i], queue);
1026 generation_name (int generation)
1028 switch (generation) {
1029 case GENERATION_NURSERY: return "nursery";
1030 case GENERATION_OLD: return "old";
1031 default: g_assert_not_reached ();
1036 sgen_generation_name (int generation)
1038 return generation_name (generation);
1042 finish_gray_stack (int generation, ScanCopyContext ctx)
1046 int done_with_ephemerons, ephemeron_rounds = 0;
1047 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1048 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1049 SgenGrayQueue *queue = ctx.queue;
1051 binary_protocol_finish_gray_stack_start (sgen_timestamp (), generation);
1053 * We copied all the reachable objects. Now it's the time to copy
1054 * the objects that were not referenced by the roots, but by the copied objects.
1055 * we built a stack of objects pointed to by gray_start: they are
1056 * additional roots and we may add more items as we go.
1057 * We loop until gray_start == gray_objects which means no more objects have
1058 * been added. Note this is iterative: no recursion is involved.
1059 * We need to walk the LO list as well in search of marked big objects
1060 * (use a flag since this is needed only on major collections). We need to loop
1061 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1062 * To achieve better cache locality and cache usage, we drain the gray stack
1063 * frequently, after each object is copied, and just finish the work here.
1065 sgen_drain_gray_stack (ctx);
1067 SGEN_LOG (2, "%s generation done", generation_name (generation));
1070 Reset bridge data, we might have lingering data from a previous collection if this is a major
1071 collection trigged by minor overflow.
1073 We must reset the gathered bridges since their original block might be evacuated due to major
1074 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1076 if (sgen_client_bridge_need_processing ())
1077 sgen_client_bridge_reset_data ();
1080 * Mark all strong toggleref objects. This must be done before we walk ephemerons or finalizers
1081 * to ensure they see the full set of live objects.
1083 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1086 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1087 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1088 * objects that are in fact reachable.
1090 done_with_ephemerons = 0;
1092 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1093 sgen_drain_gray_stack (ctx);
1095 } while (!done_with_ephemerons);
1097 if (sgen_client_bridge_need_processing ()) {
1098 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1099 sgen_drain_gray_stack (ctx);
1100 sgen_collect_bridge_objects (generation, ctx);
1101 if (generation == GENERATION_OLD)
1102 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1105 Do the first bridge step here, as the collector liveness state will become useless after that.
1107 An important optimization is to only proccess the possibly dead part of the object graph and skip
1108 over all live objects as we transitively know everything they point must be alive too.
1110 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1112 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1113 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1116 sgen_client_bridge_processing_stw_step ();
1120 Make sure we drain the gray stack before processing disappearing links and finalizers.
1121 If we don't make sure it is empty we might wrongly see a live object as dead.
1123 sgen_drain_gray_stack (ctx);
1126 We must clear weak links that don't track resurrection before processing object ready for
1127 finalization so they can be cleared before that.
1129 sgen_null_link_in_range (generation, ctx, FALSE);
1130 if (generation == GENERATION_OLD)
1131 sgen_null_link_in_range (GENERATION_NURSERY, ctx, FALSE);
1134 /* walk the finalization queue and move also the objects that need to be
1135 * finalized: use the finalized objects as new roots so the objects they depend
1136 * on are also not reclaimed. As with the roots above, only objects in the nursery
1137 * are marked/copied.
1139 sgen_finalize_in_range (generation, ctx);
1140 if (generation == GENERATION_OLD)
1141 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1142 /* drain the new stack that might have been created */
1143 SGEN_LOG (6, "Precise scan of gray area post fin");
1144 sgen_drain_gray_stack (ctx);
1147 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1149 done_with_ephemerons = 0;
1151 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1152 sgen_drain_gray_stack (ctx);
1154 } while (!done_with_ephemerons);
1156 sgen_client_clear_unreachable_ephemerons (ctx);
1159 * We clear togglerefs only after all possible chances of revival are done.
1160 * This is semantically more inline with what users expect and it allows for
1161 * user finalizers to correctly interact with TR objects.
1163 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1166 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);
1169 * handle disappearing links
1170 * Note we do this after checking the finalization queue because if an object
1171 * survives (at least long enough to be finalized) we don't clear the link.
1172 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1173 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1176 g_assert (sgen_gray_object_queue_is_empty (queue));
1178 sgen_null_link_in_range (generation, ctx, TRUE);
1179 if (generation == GENERATION_OLD)
1180 sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
1181 if (sgen_gray_object_queue_is_empty (queue))
1183 sgen_drain_gray_stack (ctx);
1186 g_assert (sgen_gray_object_queue_is_empty (queue));
1188 binary_protocol_finish_gray_stack_end (sgen_timestamp (), generation);
1192 sgen_check_section_scan_starts (GCMemSection *section)
1195 for (i = 0; i < section->num_scan_start; ++i) {
1196 if (section->scan_starts [i]) {
1197 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1198 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1204 check_scan_starts (void)
1206 if (!do_scan_starts_check)
1208 sgen_check_section_scan_starts (nursery_section);
1209 major_collector.check_scan_starts ();
1213 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1217 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
1218 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1219 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1220 } SGEN_HASH_TABLE_FOREACH_END;
1226 static gboolean inited = FALSE;
1231 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1233 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1234 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1235 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1236 mono_counters_register ("Minor scan major blocks", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_major_blocks);
1237 mono_counters_register ("Minor scan los", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_los);
1238 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1239 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1240 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1242 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1243 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1244 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1245 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1246 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1247 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1248 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1249 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1250 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1251 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1253 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1255 #ifdef HEAVY_STATISTICS
1256 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1257 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1258 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1259 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1260 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1262 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1263 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1265 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1266 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1267 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1268 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1270 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1271 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1273 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1275 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1276 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1277 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1278 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1280 sgen_nursery_allocator_init_heavy_stats ();
1288 reset_pinned_from_failed_allocation (void)
1290 bytes_pinned_from_failed_allocation = 0;
1294 sgen_set_pinned_from_failed_allocation (mword objsize)
1296 bytes_pinned_from_failed_allocation += objsize;
1300 sgen_collection_is_concurrent (void)
1302 switch (current_collection_generation) {
1303 case GENERATION_NURSERY:
1305 case GENERATION_OLD:
1306 return concurrent_collection_in_progress;
1308 g_error ("Invalid current generation %d", current_collection_generation);
1314 sgen_concurrent_collection_in_progress (void)
1316 return concurrent_collection_in_progress;
1320 SgenThreadPoolJob job;
1321 SgenObjectOperations *ops;
1322 SgenGrayQueue *gc_thread_gray_queue;
1330 static ScanCopyContext
1331 scan_copy_context_for_scan_job (void *worker_data_untyped, ScanJob *job)
1333 WorkerData *worker_data = (WorkerData *)worker_data_untyped;
1335 return CONTEXT_FROM_OBJECT_OPERATIONS (job->ops, sgen_workers_get_job_gray_queue (worker_data, job->gc_thread_gray_queue));
1343 } ScanFromRegisteredRootsJob;
1346 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1348 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1349 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1351 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1358 } ScanThreadDataJob;
1361 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1363 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1364 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1366 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1371 SgenPointerQueue *queue;
1372 } ScanFinalizerEntriesJob;
1375 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1377 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1378 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1380 scan_finalizer_entries (job_data->queue, ctx);
1384 job_scan_wbroots (void *worker_data_untyped, SgenThreadPoolJob *job)
1386 ScanJob *job_data = (ScanJob*)job;
1387 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1389 sgen_wbroots_scan_card_table (ctx);
1393 job_scan_major_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1395 SGEN_TV_DECLARE (atv);
1396 SGEN_TV_DECLARE (btv);
1397 ParallelScanJob *job_data = (ParallelScanJob*)job;
1398 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1400 SGEN_TV_GETTIME (atv);
1401 major_collector.scan_card_table (CARDTABLE_SCAN_GLOBAL, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1402 SGEN_TV_GETTIME (btv);
1403 time_minor_scan_major_blocks += SGEN_TV_ELAPSED (atv, btv);
1407 job_scan_los_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1409 SGEN_TV_DECLARE (atv);
1410 SGEN_TV_DECLARE (btv);
1411 ParallelScanJob *job_data = (ParallelScanJob*)job;
1412 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1414 SGEN_TV_GETTIME (atv);
1415 sgen_los_scan_card_table (CARDTABLE_SCAN_GLOBAL, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1416 SGEN_TV_GETTIME (btv);
1417 time_minor_scan_los += SGEN_TV_ELAPSED (atv, btv);
1421 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1423 ParallelScanJob *job_data = (ParallelScanJob*)job;
1424 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1426 g_assert (concurrent_collection_in_progress);
1427 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1431 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1433 ParallelScanJob *job_data = (ParallelScanJob*)job;
1434 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1436 g_assert (concurrent_collection_in_progress);
1437 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1441 job_major_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1443 ParallelScanJob *job_data = (ParallelScanJob*)job;
1444 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1446 g_assert (concurrent_collection_in_progress);
1448 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1452 job_los_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1454 ParallelScanJob *job_data = (ParallelScanJob*)job;
1455 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1457 g_assert (concurrent_collection_in_progress);
1459 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, sgen_workers_get_job_split_count ());
1463 job_scan_last_pinned (void *worker_data_untyped, SgenThreadPoolJob *job)
1465 ScanJob *job_data = (ScanJob*)job;
1466 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1468 g_assert (concurrent_collection_in_progress);
1470 sgen_scan_pin_queue_objects (ctx);
1474 workers_finish_callback (void)
1476 ParallelScanJob *psj;
1478 int split_count = sgen_workers_get_job_split_count ();
1480 /* Mod union preclean jobs */
1481 for (i = 0; i < split_count; i++) {
1482 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean major mod union cardtable", job_major_mod_union_preclean, sizeof (ParallelScanJob));
1483 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1484 psj->scan_job.gc_thread_gray_queue = NULL;
1486 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1489 for (i = 0; i < split_count; i++) {
1490 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean los mod union cardtable", job_los_mod_union_preclean, sizeof (ParallelScanJob));
1491 psj->scan_job.ops = sgen_workers_get_idle_func_object_ops ();
1492 psj->scan_job.gc_thread_gray_queue = NULL;
1494 sgen_workers_enqueue_job (&psj->scan_job.job, TRUE);
1497 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan last pinned", job_scan_last_pinned, sizeof (ScanJob));
1498 sj->ops = sgen_workers_get_idle_func_object_ops ();
1499 sj->gc_thread_gray_queue = NULL;
1500 sgen_workers_enqueue_job (&sj->job, TRUE);
1504 init_gray_queue (SgenGrayQueue *gc_thread_gray_queue, gboolean use_workers)
1507 sgen_workers_init_distribute_gray_queue ();
1508 sgen_gray_object_queue_init (gc_thread_gray_queue, NULL, TRUE);
1512 enqueue_scan_remembered_set_jobs (SgenGrayQueue *gc_thread_gray_queue, SgenObjectOperations *ops, gboolean enqueue)
1514 int i, split_count = sgen_workers_get_job_split_count ();
1517 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan wbroots", job_scan_wbroots, sizeof (ScanJob));
1519 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1520 sgen_workers_enqueue_job (&sj->job, enqueue);
1522 for (i = 0; i < split_count; i++) {
1523 ParallelScanJob *psj;
1525 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan major remsets", job_scan_major_card_table, sizeof (ParallelScanJob));
1526 psj->scan_job.ops = ops;
1527 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1529 sgen_workers_enqueue_job (&psj->scan_job.job, enqueue);
1531 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS remsets", job_scan_los_card_table, sizeof (ParallelScanJob));
1532 psj->scan_job.ops = ops;
1533 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1535 sgen_workers_enqueue_job (&psj->scan_job.job, enqueue);
1540 enqueue_scan_from_roots_jobs (SgenGrayQueue *gc_thread_gray_queue, char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
1542 ScanFromRegisteredRootsJob *scrrj;
1543 ScanThreadDataJob *stdj;
1544 ScanFinalizerEntriesJob *sfej;
1546 /* registered roots, this includes static fields */
1548 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1549 scrrj->scan_job.ops = ops;
1550 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1551 scrrj->heap_start = heap_start;
1552 scrrj->heap_end = heap_end;
1553 scrrj->root_type = ROOT_TYPE_NORMAL;
1554 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1556 if (current_collection_generation == GENERATION_OLD) {
1557 /* During minors we scan the cardtable for these roots instead */
1558 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1559 scrrj->scan_job.ops = ops;
1560 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1561 scrrj->heap_start = heap_start;
1562 scrrj->heap_end = heap_end;
1563 scrrj->root_type = ROOT_TYPE_WBARRIER;
1564 sgen_workers_enqueue_job (&scrrj->scan_job.job, enqueue);
1569 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1570 stdj->scan_job.ops = ops;
1571 stdj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1572 stdj->heap_start = heap_start;
1573 stdj->heap_end = heap_end;
1574 sgen_workers_enqueue_job (&stdj->scan_job.job, enqueue);
1576 /* Scan the list of objects ready for finalization. */
1578 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1579 sfej->scan_job.ops = ops;
1580 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1581 sfej->queue = &fin_ready_queue;
1582 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1584 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1585 sfej->scan_job.ops = ops;
1586 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1587 sfej->queue = &critical_fin_queue;
1588 sgen_workers_enqueue_job (&sfej->scan_job.job, enqueue);
1592 * Perform a nursery collection.
1594 * Return whether any objects were late-pinned due to being out of memory.
1597 collect_nursery (const char *reason, gboolean is_overflow, SgenGrayQueue *unpin_queue)
1599 gboolean needs_major, is_parallel = FALSE;
1600 size_t max_garbage_amount;
1602 mword fragment_total;
1603 SgenGrayQueue gc_thread_gray_queue;
1604 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
1605 ScanCopyContext ctx;
1608 SGEN_TV_DECLARE (last_minor_collection_start_tv);
1609 SGEN_TV_DECLARE (last_minor_collection_end_tv);
1611 if (disable_minor_collections)
1614 TV_GETTIME (last_minor_collection_start_tv);
1615 atv = last_minor_collection_start_tv;
1617 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1619 if (sgen_concurrent_collection_in_progress ()) {
1620 /* FIXME Support parallel nursery collections with concurrent major */
1621 object_ops_nopar = &sgen_minor_collector.serial_ops_with_concurrent_major;
1623 object_ops_nopar = &sgen_minor_collector.serial_ops;
1624 if (sgen_minor_collector.is_parallel) {
1625 object_ops_par = &sgen_minor_collector.parallel_ops;
1630 if (do_verify_nursery || do_dump_nursery_content)
1631 sgen_debug_verify_nursery (do_dump_nursery_content);
1633 current_collection_generation = GENERATION_NURSERY;
1635 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1637 reset_pinned_from_failed_allocation ();
1639 check_scan_starts ();
1641 sgen_nursery_alloc_prepare_for_minor ();
1645 nursery_next = sgen_nursery_alloc_get_upper_alloc_bound ();
1646 /* FIXME: optimize later to use the higher address where an object can be present */
1647 nursery_next = MAX (nursery_next, sgen_get_nursery_end ());
1649 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", gc_stats.minor_gc_count, sgen_get_nursery_start (), nursery_next, (int)(nursery_next - sgen_get_nursery_start ()));
1650 max_garbage_amount = nursery_next - sgen_get_nursery_start ();
1651 g_assert (nursery_section->size >= max_garbage_amount);
1653 /* world must be stopped already */
1655 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1657 sgen_client_pre_collection_checks ();
1659 nursery_section->next_data = nursery_next;
1661 major_collector.start_nursery_collection ();
1663 sgen_memgov_minor_collection_start ();
1665 init_gray_queue (&gc_thread_gray_queue, is_parallel);
1666 ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, &gc_thread_gray_queue);
1668 gc_stats.minor_gc_count ++;
1670 sgen_process_fin_stage_entries ();
1672 /* pin from pinned handles */
1673 sgen_init_pinning ();
1674 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1675 pin_from_roots (sgen_get_nursery_start (), nursery_next, ctx);
1676 /* pin cemented objects */
1677 sgen_pin_cemented_objects ();
1678 /* identify pinned objects */
1679 sgen_optimize_pin_queue ();
1680 sgen_pinning_setup_section (nursery_section);
1682 pin_objects_in_nursery (FALSE, ctx);
1683 sgen_pinning_trim_queue_to_section (nursery_section);
1685 if (remset_consistency_checks)
1686 sgen_check_remset_consistency ();
1688 if (whole_heap_check_before_collection) {
1689 sgen_clear_nursery_fragments ();
1690 sgen_check_whole_heap (FALSE);
1694 time_minor_pinning += TV_ELAPSED (btv, atv);
1695 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (btv, atv));
1696 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1698 remset.start_scan_remsets ();
1700 enqueue_scan_remembered_set_jobs (&gc_thread_gray_queue, is_parallel ? object_ops_par : object_ops_nopar, is_parallel);
1702 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1704 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1705 SGEN_LOG (2, "Old generation scan: %lld usecs", (long long)TV_ELAPSED (atv, btv));
1707 sgen_pin_stats_report ();
1709 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1710 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1713 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1715 enqueue_scan_from_roots_jobs (&gc_thread_gray_queue, sgen_get_nursery_start (), nursery_next, is_parallel ? object_ops_par : object_ops_nopar, is_parallel);
1718 gray_queue_redirect (&gc_thread_gray_queue);
1719 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1720 sgen_workers_join ();
1724 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1726 finish_gray_stack (GENERATION_NURSERY, ctx);
1729 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1730 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1732 if (objects_pinned) {
1733 sgen_optimize_pin_queue ();
1734 sgen_pinning_setup_section (nursery_section);
1738 * This is the latest point at which we can do this check, because
1739 * sgen_build_nursery_fragments() unpins nursery objects again.
1741 if (remset_consistency_checks)
1742 sgen_check_remset_consistency ();
1744 /* walk the pin_queue, build up the fragment list of free memory, unmark
1745 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1748 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1749 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1750 if (!fragment_total)
1753 /* Clear TLABs for all threads */
1754 sgen_clear_tlabs ();
1756 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1758 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1759 SGEN_LOG (2, "Fragment creation: %lld usecs, %lu bytes available", (long long)TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1761 if (remset_consistency_checks)
1762 sgen_check_major_refs ();
1764 major_collector.finish_nursery_collection ();
1766 TV_GETTIME (last_minor_collection_end_tv);
1767 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1769 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1771 /* prepare the pin queue for the next collection */
1772 sgen_finish_pinning ();
1773 if (sgen_have_pending_finalizers ()) {
1774 SGEN_LOG (4, "Finalizer-thread wakeup");
1775 sgen_client_finalize_notify ();
1777 sgen_pin_stats_reset ();
1778 /* clear cemented hash */
1779 sgen_cement_clear_below_threshold ();
1781 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
1783 check_scan_starts ();
1785 binary_protocol_flush_buffers (FALSE);
1787 sgen_memgov_minor_collection_end (reason, is_overflow);
1789 /*objects are late pinned because of lack of memory, so a major is a good call*/
1790 needs_major = objects_pinned > 0;
1791 current_collection_generation = -1;
1794 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1796 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1797 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1803 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1804 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1805 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1806 } CopyOrMarkFromRootsMode;
1809 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)
1814 /* FIXME: only use these values for the precise scan
1815 * note that to_space pointers should be excluded anyway...
1817 char *heap_start = NULL;
1818 char *heap_end = (char*)-1;
1819 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue);
1820 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1822 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1824 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1825 /*This cleans up unused fragments */
1826 sgen_nursery_allocator_prepare_for_pinning ();
1828 if (do_concurrent_checks)
1829 sgen_debug_check_nursery_is_clean ();
1831 /* The concurrent collector doesn't touch the nursery. */
1832 sgen_nursery_alloc_prepare_for_major ();
1837 /* Pinning depends on this */
1838 sgen_clear_nursery_fragments ();
1840 if (whole_heap_check_before_collection)
1841 sgen_check_whole_heap (TRUE);
1844 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1846 if (!sgen_collection_is_concurrent ())
1847 nursery_section->next_data = sgen_get_nursery_end ();
1848 /* we should also coalesce scanning from sections close to each other
1849 * and deal with pointers outside of the sections later.
1854 sgen_client_pre_collection_checks ();
1856 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1857 /* Remsets are not useful for a major collection */
1858 remset.clear_cards ();
1861 sgen_process_fin_stage_entries ();
1864 sgen_init_pinning ();
1865 SGEN_LOG (6, "Collecting pinned addresses");
1866 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1867 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1868 /* Pin cemented objects that were forced */
1869 sgen_pin_cemented_objects ();
1871 sgen_optimize_pin_queue ();
1872 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1874 * Cemented objects that are in the pinned list will be marked. When
1875 * marking concurrently we won't mark mod-union cards for these objects.
1876 * Instead they will remain cemented until the next major collection,
1877 * when we will recheck if they are still pinned in the roots.
1879 sgen_cement_force_pinned ();
1882 sgen_client_collecting_major_1 ();
1885 * pin_queue now contains all candidate pointers, sorted and
1886 * uniqued. We must do two passes now to figure out which
1887 * objects are pinned.
1889 * The first is to find within the pin_queue the area for each
1890 * section. This requires that the pin_queue be sorted. We
1891 * also process the LOS objects and pinned chunks here.
1893 * The second, destructive, pass is to reduce the section
1894 * areas to pointers to the actually pinned objects.
1896 SGEN_LOG (6, "Pinning from sections");
1897 /* first pass for the sections */
1898 sgen_find_section_pin_queue_start_end (nursery_section);
1899 /* identify possible pointers to the insize of large objects */
1900 SGEN_LOG (6, "Pinning from large objects");
1901 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1903 if (sgen_find_optimized_pin_queue_area ((char*)bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1904 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
1906 if (sgen_los_object_is_pinned (bigobj->data)) {
1907 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1910 sgen_los_pin_object (bigobj->data);
1911 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1912 GRAY_OBJECT_ENQUEUE_SERIAL (gc_thread_gray_queue, bigobj->data, sgen_obj_get_descriptor ((GCObject*)bigobj->data));
1913 sgen_pin_stats_register_object (bigobj->data, GENERATION_OLD);
1914 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1915 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1916 (unsigned long)sgen_los_object_size (bigobj));
1918 sgen_client_pinned_los_object (bigobj->data);
1922 pin_objects_in_nursery (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT, ctx);
1923 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1924 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1926 major_collector.pin_objects (gc_thread_gray_queue);
1927 if (old_next_pin_slot)
1928 *old_next_pin_slot = sgen_get_pinned_count ();
1931 time_major_pinning += TV_ELAPSED (atv, btv);
1932 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (atv, btv));
1933 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1935 major_collector.init_to_space ();
1937 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1938 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1939 if (object_ops_par != NULL)
1940 sgen_workers_set_num_active_workers (0);
1941 if (sgen_workers_have_idle_work ()) {
1943 * We force the finish of the worker with the new object ops context
1944 * which can also do copying. We need to have finished pinning.
1946 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1948 sgen_workers_join ();
1952 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
1953 main_gc_thread = mono_native_thread_self ();
1956 sgen_client_collecting_major_2 ();
1959 time_major_scan_pinned += TV_ELAPSED (btv, atv);
1961 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
1963 enqueue_scan_from_roots_jobs (gc_thread_gray_queue, heap_start, heap_end, object_ops_nopar, FALSE);
1966 time_major_scan_roots += TV_ELAPSED (atv, btv);
1969 * We start the concurrent worker after pinning and after we scanned the roots
1970 * in order to make sure that the worker does not finish before handling all
1973 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1974 sgen_workers_set_num_active_workers (1);
1975 gray_queue_redirect (gc_thread_gray_queue);
1976 if (precleaning_enabled) {
1977 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, workers_finish_callback);
1979 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
1983 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1984 int i, split_count = sgen_workers_get_job_split_count ();
1985 gboolean parallel = object_ops_par != NULL;
1987 /* If we're not parallel we finish the collection on the gc thread */
1989 gray_queue_redirect (gc_thread_gray_queue);
1991 /* Mod union card table */
1992 for (i = 0; i < split_count; i++) {
1993 ParallelScanJob *psj;
1995 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ParallelScanJob));
1996 psj->scan_job.ops = object_ops_par ? object_ops_par : object_ops_nopar;
1997 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1999 sgen_workers_enqueue_job (&psj->scan_job.job, parallel);
2001 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ParallelScanJob));
2002 psj->scan_job.ops = object_ops_par ? object_ops_par : object_ops_nopar;
2003 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
2005 sgen_workers_enqueue_job (&psj->scan_job.job, parallel);
2010 * If we enqueue a job while workers are running we need to sgen_workers_ensure_awake
2011 * in order to make sure that we are running the idle func and draining all worker
2012 * gray queues. The operation of starting workers implies this, so we start them after
2013 * in order to avoid doing this operation twice. The workers will drain the main gray
2014 * stack that contained roots and pinned objects and also scan the mod union card
2017 sgen_workers_start_all_workers (object_ops_nopar, object_ops_par, NULL);
2018 sgen_workers_join ();
2022 sgen_pin_stats_report ();
2024 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
2025 sgen_finish_pinning ();
2027 sgen_pin_stats_reset ();
2029 if (do_concurrent_checks)
2030 sgen_debug_check_nursery_is_clean ();
2035 major_start_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean concurrent, size_t *old_next_pin_slot)
2037 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
2039 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2041 current_collection_generation = GENERATION_OLD;
2043 sgen_workers_assert_gray_queue_is_empty ();
2046 sgen_cement_reset ();
2049 g_assert (major_collector.is_concurrent);
2050 concurrent_collection_in_progress = TRUE;
2052 object_ops_nopar = &major_collector.major_ops_concurrent_start;
2053 if (major_collector.is_parallel)
2054 object_ops_par = &major_collector.major_ops_conc_par_start;
2057 object_ops_nopar = &major_collector.major_ops_serial;
2060 reset_pinned_from_failed_allocation ();
2062 sgen_memgov_major_collection_start (concurrent, reason);
2064 //count_ref_nonref_objs ();
2065 //consistency_check ();
2067 check_scan_starts ();
2070 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2071 gc_stats.major_gc_count ++;
2073 if (major_collector.start_major_collection)
2074 major_collector.start_major_collection ();
2076 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);
2080 major_finish_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean is_overflow, size_t old_next_pin_slot, gboolean forced)
2082 ScannedObjectCounts counts;
2083 SgenObjectOperations *object_ops_nopar;
2084 mword fragment_total;
2090 if (concurrent_collection_in_progress) {
2091 SgenObjectOperations *object_ops_par = NULL;
2093 object_ops_nopar = &major_collector.major_ops_concurrent_finish;
2094 if (major_collector.is_parallel)
2095 object_ops_par = &major_collector.major_ops_conc_par_finish;
2097 major_copy_or_mark_from_roots (gc_thread_gray_queue, NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, object_ops_nopar, object_ops_par);
2099 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2100 main_gc_thread = NULL;
2103 object_ops_nopar = &major_collector.major_ops_serial;
2106 sgen_workers_assert_gray_queue_is_empty ();
2108 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue));
2110 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2112 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2114 if (objects_pinned) {
2115 g_assert (!concurrent_collection_in_progress);
2118 * This is slow, but we just OOM'd.
2120 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2121 * queue is laid out at this point.
2123 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2125 * We need to reestablish all pinned nursery objects in the pin queue
2126 * because they're needed for fragment creation. Unpinning happens by
2127 * walking the whole queue, so it's not necessary to reestablish where major
2128 * heap block pins are - all we care is that they're still in there
2131 sgen_optimize_pin_queue ();
2132 sgen_find_section_pin_queue_start_end (nursery_section);
2136 reset_heap_boundaries ();
2137 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2139 /* walk the pin_queue, build up the fragment list of free memory, unmark
2140 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2143 fragment_total = sgen_build_nursery_fragments (nursery_section, NULL);
2144 if (!fragment_total)
2146 SGEN_LOG (4, "Free space in nursery after major %ld", (long)fragment_total);
2148 if (do_concurrent_checks && concurrent_collection_in_progress)
2149 sgen_debug_check_nursery_is_clean ();
2151 /* prepare the pin queue for the next collection */
2152 sgen_finish_pinning ();
2154 /* Clear TLABs for all threads */
2155 sgen_clear_tlabs ();
2157 sgen_pin_stats_reset ();
2159 sgen_cement_clear_below_threshold ();
2161 if (check_mark_bits_after_major_collection)
2162 sgen_check_heap_marked (concurrent_collection_in_progress);
2165 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2167 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2168 sgen_memgov_major_pre_sweep ();
2171 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2176 time_major_los_sweep += TV_ELAPSED (atv, btv);
2178 major_collector.sweep ();
2180 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2183 time_major_sweep += TV_ELAPSED (btv, atv);
2185 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2187 if (sgen_have_pending_finalizers ()) {
2188 SGEN_LOG (4, "Finalizer-thread wakeup");
2189 sgen_client_finalize_notify ();
2192 sgen_memgov_major_collection_end (forced, concurrent_collection_in_progress, reason, is_overflow);
2193 current_collection_generation = -1;
2195 memset (&counts, 0, sizeof (ScannedObjectCounts));
2196 major_collector.finish_major_collection (&counts);
2198 sgen_workers_assert_gray_queue_is_empty ();
2200 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2201 if (concurrent_collection_in_progress)
2202 concurrent_collection_in_progress = FALSE;
2204 check_scan_starts ();
2206 binary_protocol_flush_buffers (FALSE);
2208 //consistency_check ();
2210 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2214 major_do_collection (const char *reason, gboolean is_overflow, gboolean forced)
2216 TV_DECLARE (time_start);
2217 TV_DECLARE (time_end);
2218 size_t old_next_pin_slot;
2219 SgenGrayQueue gc_thread_gray_queue;
2221 if (disable_major_collections)
2224 if (major_collector.get_and_reset_num_major_objects_marked) {
2225 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2226 g_assert (!num_marked);
2229 /* world must be stopped already */
2230 TV_GETTIME (time_start);
2232 init_gray_queue (&gc_thread_gray_queue, FALSE);
2233 major_start_collection (&gc_thread_gray_queue, reason, FALSE, &old_next_pin_slot);
2234 major_finish_collection (&gc_thread_gray_queue, reason, is_overflow, old_next_pin_slot, forced);
2235 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2237 TV_GETTIME (time_end);
2238 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2240 /* FIXME: also report this to the user, preferably in gc-end. */
2241 if (major_collector.get_and_reset_num_major_objects_marked)
2242 major_collector.get_and_reset_num_major_objects_marked ();
2244 return bytes_pinned_from_failed_allocation > 0;
2248 major_start_concurrent_collection (const char *reason)
2250 TV_DECLARE (time_start);
2251 TV_DECLARE (time_end);
2252 long long num_objects_marked;
2253 SgenGrayQueue gc_thread_gray_queue;
2255 if (disable_major_collections)
2258 TV_GETTIME (time_start);
2259 SGEN_TV_GETTIME (time_major_conc_collection_start);
2261 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2262 g_assert (num_objects_marked == 0);
2264 binary_protocol_concurrent_start ();
2266 init_gray_queue (&gc_thread_gray_queue, TRUE);
2267 // FIXME: store reason and pass it when finishing
2268 major_start_collection (&gc_thread_gray_queue, reason, TRUE, NULL);
2269 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2271 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2273 TV_GETTIME (time_end);
2274 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2276 current_collection_generation = -1;
2280 * Returns whether the major collection has finished.
2283 major_should_finish_concurrent_collection (void)
2285 return sgen_workers_all_done ();
2289 major_update_concurrent_collection (void)
2291 TV_DECLARE (total_start);
2292 TV_DECLARE (total_end);
2294 TV_GETTIME (total_start);
2296 binary_protocol_concurrent_update ();
2298 major_collector.update_cardtable_mod_union ();
2299 sgen_los_update_cardtable_mod_union ();
2301 TV_GETTIME (total_end);
2302 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2306 major_finish_concurrent_collection (gboolean forced)
2308 SgenGrayQueue gc_thread_gray_queue;
2309 TV_DECLARE (total_start);
2310 TV_DECLARE (total_end);
2312 TV_GETTIME (total_start);
2314 binary_protocol_concurrent_finish ();
2317 * We need to stop all workers since we're updating the cardtable below.
2318 * The workers will be resumed with a finishing pause context to avoid
2319 * additional cardtable and object scanning.
2321 sgen_workers_stop_all_workers ();
2323 SGEN_TV_GETTIME (time_major_conc_collection_end);
2324 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2326 major_collector.update_cardtable_mod_union ();
2327 sgen_los_update_cardtable_mod_union ();
2329 if (mod_union_consistency_check)
2330 sgen_check_mod_union_consistency ();
2332 current_collection_generation = GENERATION_OLD;
2333 sgen_cement_reset ();
2334 init_gray_queue (&gc_thread_gray_queue, FALSE);
2335 major_finish_collection (&gc_thread_gray_queue, "finishing", FALSE, -1, forced);
2336 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2338 TV_GETTIME (total_end);
2339 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2341 current_collection_generation = -1;
2345 * Ensure an allocation request for @size will succeed by freeing enough memory.
2347 * LOCKING: The GC lock MUST be held.
2350 sgen_ensure_free_space (size_t size, int generation)
2352 int generation_to_collect = -1;
2353 const char *reason = NULL;
2355 if (generation == GENERATION_OLD) {
2356 if (sgen_need_major_collection (size)) {
2357 reason = "LOS overflow";
2358 generation_to_collect = GENERATION_OLD;
2361 if (degraded_mode) {
2362 if (sgen_need_major_collection (size)) {
2363 reason = "Degraded mode overflow";
2364 generation_to_collect = GENERATION_OLD;
2366 } else if (sgen_need_major_collection (size)) {
2367 reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
2368 generation_to_collect = GENERATION_OLD;
2370 generation_to_collect = GENERATION_NURSERY;
2371 reason = "Nursery full";
2375 if (generation_to_collect == -1) {
2376 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2377 generation_to_collect = GENERATION_OLD;
2378 reason = "Finish concurrent collection";
2382 if (generation_to_collect == -1)
2384 sgen_perform_collection (size, generation_to_collect, reason, FALSE, TRUE);
2388 * LOCKING: Assumes the GC lock is held.
2391 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw)
2393 TV_DECLARE (gc_total_start);
2394 TV_DECLARE (gc_total_end);
2395 int overflow_generation_to_collect = -1;
2396 int oldest_generation_collected = generation_to_collect;
2397 const char *overflow_reason = NULL;
2398 gboolean finish_concurrent = concurrent_collection_in_progress && (major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD);
2400 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2402 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2405 sgen_stop_world (generation_to_collect);
2407 SGEN_ASSERT (0, sgen_is_world_stopped (), "We can only collect if the world is stopped");
2410 TV_GETTIME (gc_total_start);
2412 // FIXME: extract overflow reason
2413 // FIXME: minor overflow for concurrent case
2414 if (generation_to_collect == GENERATION_NURSERY && !finish_concurrent) {
2415 if (concurrent_collection_in_progress)
2416 major_update_concurrent_collection ();
2418 if (collect_nursery (reason, FALSE, NULL) && !concurrent_collection_in_progress) {
2419 overflow_generation_to_collect = GENERATION_OLD;
2420 overflow_reason = "Minor overflow";
2422 } else if (finish_concurrent) {
2423 major_finish_concurrent_collection (wait_to_finish);
2424 oldest_generation_collected = GENERATION_OLD;
2426 SGEN_ASSERT (0, generation_to_collect == GENERATION_OLD, "We should have handled nursery collections above");
2427 if (major_collector.is_concurrent && !wait_to_finish) {
2428 collect_nursery ("Concurrent start", FALSE, NULL);
2429 major_start_concurrent_collection (reason);
2430 oldest_generation_collected = GENERATION_NURSERY;
2431 } else if (major_do_collection (reason, FALSE, wait_to_finish)) {
2432 overflow_generation_to_collect = GENERATION_NURSERY;
2433 overflow_reason = "Excessive pinning";
2437 if (overflow_generation_to_collect != -1) {
2438 SGEN_ASSERT (0, !concurrent_collection_in_progress, "We don't yet support overflow collections with the concurrent collector");
2441 * We need to do an overflow collection, either because we ran out of memory
2442 * or the nursery is fully pinned.
2445 if (overflow_generation_to_collect == GENERATION_NURSERY)
2446 collect_nursery (overflow_reason, TRUE, NULL);
2448 major_do_collection (overflow_reason, TRUE, wait_to_finish);
2450 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2453 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2455 /* this also sets the proper pointers for the next allocation */
2456 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2457 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2458 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2459 sgen_dump_pin_queue ();
2463 TV_GETTIME (gc_total_end);
2464 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2467 sgen_restart_world (oldest_generation_collected);
2471 * ######################################################################
2472 * ######## Memory allocation from the OS
2473 * ######################################################################
2474 * This section of code deals with getting memory from the OS and
2475 * allocating memory for GC-internal data structures.
2476 * Internal memory can be handled with a freelist for small objects.
2482 G_GNUC_UNUSED static void
2483 report_internal_mem_usage (void)
2485 printf ("Internal memory usage:\n");
2486 sgen_report_internal_mem_usage ();
2487 printf ("Pinned memory usage:\n");
2488 major_collector.report_pinned_memory_usage ();
2492 * ######################################################################
2493 * ######## Finalization support
2494 * ######################################################################
2498 * If the object has been forwarded it means it's still referenced from a root.
2499 * If it is pinned it's still alive as well.
2500 * A LOS object is only alive if we have pinned it.
2501 * Return TRUE if @obj is ready to be finalized.
2503 static inline gboolean
2504 sgen_is_object_alive (GCObject *object)
2506 if (ptr_in_nursery (object))
2507 return sgen_nursery_is_object_alive (object);
2509 return sgen_major_is_object_alive (object);
2513 * This function returns true if @object is either alive and belongs to the
2514 * current collection - major collections are full heap, so old gen objects
2515 * are never alive during a minor collection.
2518 sgen_is_object_alive_and_on_current_collection (GCObject *object)
2520 if (ptr_in_nursery (object))
2521 return sgen_nursery_is_object_alive (object);
2523 if (current_collection_generation == GENERATION_NURSERY)
2526 return sgen_major_is_object_alive (object);
2531 sgen_gc_is_object_ready_for_finalization (GCObject *object)
2533 return !sgen_is_object_alive (object);
2537 sgen_queue_finalization_entry (GCObject *obj)
2539 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2541 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2543 sgen_client_object_queued_for_finalization (obj);
2547 sgen_object_is_live (GCObject *obj)
2549 return sgen_is_object_alive_and_on_current_collection (obj);
2553 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2554 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2555 * all finalizers have really finished running.
2557 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2558 * This means that just checking whether the queues are empty leaves the possibility that an
2559 * object might have been dequeued but not yet finalized. That's why we need the additional
2560 * flag `pending_unqueued_finalizer`.
2563 static volatile gboolean pending_unqueued_finalizer = FALSE;
2564 volatile gboolean sgen_suspend_finalizers = FALSE;
2567 sgen_set_suspend_finalizers (void)
2569 sgen_suspend_finalizers = TRUE;
2573 sgen_gc_invoke_finalizers (void)
2577 g_assert (!pending_unqueued_finalizer);
2579 /* FIXME: batch to reduce lock contention */
2580 while (sgen_have_pending_finalizers ()) {
2586 * We need to set `pending_unqueued_finalizer` before dequeing the
2587 * finalizable object.
2589 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2590 pending_unqueued_finalizer = TRUE;
2591 mono_memory_write_barrier ();
2592 obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
2593 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2594 pending_unqueued_finalizer = TRUE;
2595 mono_memory_write_barrier ();
2596 obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
2602 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2610 /* the object is on the stack so it is pinned */
2611 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2612 sgen_client_run_finalize (obj);
2615 if (pending_unqueued_finalizer) {
2616 mono_memory_write_barrier ();
2617 pending_unqueued_finalizer = FALSE;
2624 sgen_have_pending_finalizers (void)
2626 if (sgen_suspend_finalizers)
2628 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2632 * ######################################################################
2633 * ######## registered roots support
2634 * ######################################################################
2638 * We do not coalesce roots.
2641 sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg)
2643 RootRecord new_root;
2646 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2647 RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
2648 /* we allow changing the size and the descriptor (for thread statics etc) */
2650 size_t old_size = root->end_root - start;
2651 root->end_root = start + size;
2652 SGEN_ASSERT (0, !!root->root_desc == !!descr, "Can't change whether a root is precise or conservative.");
2653 SGEN_ASSERT (0, root->source == source, "Can't change a root's source identifier.");
2654 SGEN_ASSERT (0, !!root->msg == !!msg, "Can't change a root's message.");
2655 root->root_desc = descr;
2657 roots_size -= old_size;
2663 new_root.end_root = start + size;
2664 new_root.root_desc = descr;
2665 new_root.source = source;
2668 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2671 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);
2678 sgen_deregister_root (char* addr)
2684 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2685 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2686 roots_size -= (root.end_root - addr);
2692 sgen_wbroots_iterate_live_block_ranges (sgen_cardtable_block_callback cb)
2696 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_WBARRIER], void **, start_root, RootRecord *, root) {
2697 cb ((mword)start_root, (mword)root->end_root - (mword)start_root);
2698 } SGEN_HASH_TABLE_FOREACH_END;
2701 /* Root equivalent of sgen_client_cardtable_scan_object */
2703 sgen_wbroot_scan_card_table (void** start_root, mword size, ScanCopyContext ctx)
2705 ScanPtrFieldFunc scan_field_func = ctx.ops->scan_ptr_field;
2706 guint8 *card_data = sgen_card_table_get_card_scan_address ((mword)start_root);
2707 guint8 *card_base = card_data;
2708 mword card_count = sgen_card_table_number_of_cards_in_range ((mword)start_root, size);
2709 guint8 *card_data_end = card_data + card_count;
2710 mword extra_idx = 0;
2711 char *obj_start = sgen_card_table_align_pointer (start_root);
2712 char *obj_end = (char*)start_root + size;
2713 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2714 guint8 *overflow_scan_end = NULL;
2717 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2718 /*Check for overflow and if so, setup to scan in two steps*/
2719 if (card_data_end >= SGEN_SHADOW_CARDTABLE_END) {
2720 overflow_scan_end = sgen_shadow_cardtable + (card_data_end - SGEN_SHADOW_CARDTABLE_END);
2721 card_data_end = SGEN_SHADOW_CARDTABLE_END;
2727 card_data = sgen_find_next_card (card_data, card_data_end);
2729 for (; card_data < card_data_end; card_data = sgen_find_next_card (card_data + 1, card_data_end)) {
2730 size_t idx = (card_data - card_base) + extra_idx;
2731 char *start = (char*)(obj_start + idx * CARD_SIZE_IN_BYTES);
2732 char *card_end = start + CARD_SIZE_IN_BYTES;
2733 char *elem = start, *first_elem = start;
2736 * Don't clean first and last card on 32bit systems since they
2737 * may also be part from other roots.
2739 if (card_data != card_base && card_data != (card_data_end - 1))
2740 sgen_card_table_prepare_card_for_scanning (card_data);
2742 card_end = MIN (card_end, obj_end);
2744 if (elem < (char*)start_root)
2745 first_elem = elem = (char*)start_root;
2747 for (; elem < card_end; elem += SIZEOF_VOID_P) {
2748 if (*(GCObject**)elem)
2749 scan_field_func (NULL, (GCObject**)elem, ctx.queue);
2752 binary_protocol_card_scan (first_elem, elem - first_elem);
2755 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2756 if (overflow_scan_end) {
2757 extra_idx = card_data - card_base;
2758 card_base = card_data = sgen_shadow_cardtable;
2759 card_data_end = overflow_scan_end;
2760 overflow_scan_end = NULL;
2767 sgen_wbroots_scan_card_table (ScanCopyContext ctx)
2772 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_WBARRIER], void **, start_root, RootRecord *, root) {
2773 SGEN_ASSERT (0, (root->root_desc & ROOT_DESC_TYPE_MASK) == ROOT_DESC_VECTOR, "Unsupported root type");
2775 sgen_wbroot_scan_card_table (start_root, (mword)root->end_root - (mword)start_root, ctx);
2776 } SGEN_HASH_TABLE_FOREACH_END;
2780 * ######################################################################
2781 * ######## Thread handling (stop/start code)
2782 * ######################################################################
2786 sgen_get_current_collection_generation (void)
2788 return current_collection_generation;
2792 sgen_thread_register (SgenThreadInfo* info, void *stack_bottom_fallback)
2794 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2796 sgen_client_thread_register (info, stack_bottom_fallback);
2802 sgen_thread_unregister (SgenThreadInfo *p)
2804 sgen_client_thread_unregister (p);
2808 * ######################################################################
2809 * ######## Write barriers
2810 * ######################################################################
2814 * Note: the write barriers first do the needed GC work and then do the actual store:
2815 * this way the value is visible to the conservative GC scan after the write barrier
2816 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2817 * the conservative scan, otherwise by the remembered set scan.
2821 * mono_gc_wbarrier_arrayref_copy:
2824 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2826 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2827 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2828 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2829 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2833 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2834 if (binary_protocol_is_heavy_enabled ()) {
2836 for (i = 0; i < count; ++i) {
2837 gpointer dest = (gpointer*)dest_ptr + i;
2838 gpointer obj = *((gpointer*)src_ptr + i);
2840 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2845 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2849 * mono_gc_wbarrier_generic_nostore:
2852 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2856 HEAVY_STAT (++stat_wbarrier_generic_store);
2858 sgen_client_wbarrier_generic_nostore_check (ptr);
2860 obj = *(gpointer*)ptr;
2862 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2865 * We need to record old->old pointer locations for the
2866 * concurrent collector.
2868 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2869 SGEN_LOG (8, "Skipping remset at %p", ptr);
2873 SGEN_LOG (8, "Adding remset at %p", ptr);
2875 remset.wbarrier_generic_nostore (ptr);
2879 * mono_gc_wbarrier_generic_store:
2882 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2884 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2885 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2886 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2887 mono_gc_wbarrier_generic_nostore (ptr);
2888 sgen_dummy_use (value);
2892 * mono_gc_wbarrier_generic_store_atomic:
2893 * Same as \c mono_gc_wbarrier_generic_store but performs the store
2894 * as an atomic operation with release semantics.
2897 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2899 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2901 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2903 InterlockedWritePointer ((volatile gpointer *)ptr, value);
2905 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2906 mono_gc_wbarrier_generic_nostore (ptr);
2908 sgen_dummy_use (value);
2912 sgen_wbarrier_value_copy_bitmap (gpointer _dest, gpointer _src, int size, unsigned bitmap)
2914 GCObject **dest = (GCObject **)_dest;
2915 GCObject **src = (GCObject **)_src;
2919 mono_gc_wbarrier_generic_store (dest, *src);
2924 size -= SIZEOF_VOID_P;
2930 * ######################################################################
2931 * ######## Other mono public interface functions.
2932 * ######################################################################
2936 sgen_gc_collect (int generation)
2941 sgen_perform_collection (0, generation, "user request", TRUE, TRUE);
2946 sgen_gc_collection_count (int generation)
2948 if (generation == 0)
2949 return gc_stats.minor_gc_count;
2950 return gc_stats.major_gc_count;
2954 sgen_gc_get_used_size (void)
2958 tot = los_memory_usage;
2959 tot += nursery_section->next_data - nursery_section->data;
2960 tot += major_collector.get_used_size ();
2961 /* FIXME: account for pinned objects */
2967 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
2971 va_start (ap, description_format);
2973 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
2974 vfprintf (stderr, description_format, ap);
2976 fprintf (stderr, " - %s", fallback);
2977 fprintf (stderr, "\n");
2983 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
2986 double val = strtod (opt, &endptr);
2987 if (endptr == opt) {
2988 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
2991 else if (val < min || val > max) {
2992 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
3004 char *major_collector_opt = NULL;
3005 char *minor_collector_opt = NULL;
3006 char *params_opts = NULL;
3007 char *debug_opts = NULL;
3008 size_t max_heap = 0;
3009 size_t soft_limit = 0;
3011 gboolean debug_print_allowance = FALSE;
3012 double allowance_ratio = 0, save_target = 0;
3013 gboolean cement_enabled = TRUE;
3016 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
3019 /* already inited */
3022 /* being inited by another thread */
3023 mono_thread_info_usleep (1000);
3026 /* we will init it */
3029 g_assert_not_reached ();
3031 } while (result != 0);
3033 SGEN_TV_GETTIME (sgen_init_timestamp);
3035 #ifdef SGEN_WITHOUT_MONO
3036 mono_thread_smr_init ();
3039 mono_coop_mutex_init (&gc_mutex);
3041 gc_debug_file = stderr;
3043 mono_coop_mutex_init (&sgen_interruption_mutex);
3045 if ((env = g_getenv (MONO_GC_PARAMS_NAME)) || gc_params_options) {
3046 params_opts = g_strdup_printf ("%s,%s", gc_params_options ? gc_params_options : "", env ? env : "");
3051 opts = g_strsplit (params_opts, ",", -1);
3052 for (ptr = opts; *ptr; ++ptr) {
3054 if (g_str_has_prefix (opt, "major=")) {
3055 opt = strchr (opt, '=') + 1;
3056 major_collector_opt = g_strdup (opt);
3057 } else if (g_str_has_prefix (opt, "minor=")) {
3058 opt = strchr (opt, '=') + 1;
3059 minor_collector_opt = g_strdup (opt);
3067 sgen_init_internal_allocator ();
3068 sgen_init_nursery_allocator ();
3069 sgen_init_fin_weak_hash ();
3070 sgen_init_hash_table ();
3071 sgen_init_descriptors ();
3072 sgen_init_gray_queues ();
3073 sgen_init_allocator ();
3074 sgen_init_gchandles ();
3076 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
3077 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
3079 sgen_client_init ();
3081 if (!minor_collector_opt) {
3082 sgen_simple_nursery_init (&sgen_minor_collector, FALSE);
3084 if (!strcmp (minor_collector_opt, "simple")) {
3086 sgen_simple_nursery_init (&sgen_minor_collector, FALSE);
3087 } else if (!strcmp (minor_collector_opt, "simple-par")) {
3088 sgen_simple_nursery_init (&sgen_minor_collector, TRUE);
3089 } else if (!strcmp (minor_collector_opt, "split")) {
3090 sgen_split_nursery_init (&sgen_minor_collector);
3092 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `simple` instead.", "Unknown minor collector `%s'.", minor_collector_opt);
3093 goto use_simple_nursery;
3097 if (!major_collector_opt) {
3099 DEFAULT_MAJOR_INIT (&major_collector);
3100 } else if (!strcmp (major_collector_opt, "marksweep")) {
3101 sgen_marksweep_init (&major_collector);
3102 } else if (!strcmp (major_collector_opt, "marksweep-conc")) {
3103 sgen_marksweep_conc_init (&major_collector);
3104 } else if (!strcmp (major_collector_opt, "marksweep-conc-par")) {
3105 sgen_marksweep_conc_par_init (&major_collector);
3107 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using `" DEFAULT_MAJOR_NAME "` instead.", "Unknown major collector `%s'.", major_collector_opt);
3108 goto use_default_major;
3111 sgen_nursery_size = DEFAULT_NURSERY_SIZE;
3114 gboolean usage_printed = FALSE;
3116 for (ptr = opts; *ptr; ++ptr) {
3118 if (!strcmp (opt, ""))
3120 if (g_str_has_prefix (opt, "major="))
3122 if (g_str_has_prefix (opt, "minor="))
3124 if (g_str_has_prefix (opt, "max-heap-size=")) {
3125 size_t page_size = mono_pagesize ();
3126 size_t max_heap_candidate = 0;
3127 opt = strchr (opt, '=') + 1;
3128 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
3129 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
3130 if (max_heap != max_heap_candidate)
3131 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
3133 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
3137 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
3138 opt = strchr (opt, '=') + 1;
3139 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
3140 if (soft_limit <= 0) {
3141 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
3145 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
3151 if (g_str_has_prefix (opt, "nursery-size=")) {
3153 opt = strchr (opt, '=') + 1;
3154 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
3155 if ((val & (val - 1))) {
3156 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
3160 if (val < SGEN_MAX_NURSERY_WASTE) {
3161 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3162 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
3166 sgen_nursery_size = val;
3167 sgen_nursery_bits = 0;
3168 while (ONE_P << (++ sgen_nursery_bits) != sgen_nursery_size)
3171 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
3177 if (g_str_has_prefix (opt, "save-target-ratio=")) {
3179 opt = strchr (opt, '=') + 1;
3180 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
3181 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
3186 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
3188 opt = strchr (opt, '=') + 1;
3189 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
3190 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3191 allowance_ratio = val;
3196 if (!strcmp (opt, "cementing")) {
3197 cement_enabled = TRUE;
3200 if (!strcmp (opt, "no-cementing")) {
3201 cement_enabled = FALSE;
3205 if (!strcmp (opt, "precleaning")) {
3206 precleaning_enabled = TRUE;
3209 if (!strcmp (opt, "no-precleaning")) {
3210 precleaning_enabled = FALSE;
3214 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3217 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3220 if (sgen_client_handle_gc_param (opt))
3223 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3228 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3229 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3230 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3231 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3232 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3233 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3234 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3235 fprintf (stderr, " [no-]cementing\n");
3236 if (major_collector.print_gc_param_usage)
3237 major_collector.print_gc_param_usage ();
3238 if (sgen_minor_collector.print_gc_param_usage)
3239 sgen_minor_collector.print_gc_param_usage ();
3240 sgen_client_print_gc_params_usage ();
3241 fprintf (stderr, " Experimental options:\n");
3242 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3243 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);
3244 fprintf (stderr, "\n");
3246 usage_printed = TRUE;
3251 if (major_collector_opt)
3252 g_free (major_collector_opt);
3254 if (minor_collector_opt)
3255 g_free (minor_collector_opt);
3258 g_free (params_opts);
3262 sgen_pinning_init ();
3263 sgen_cement_init (cement_enabled);
3265 if ((env = g_getenv (MONO_GC_DEBUG_NAME)) || gc_debug_options) {
3266 debug_opts = g_strdup_printf ("%s,%s", gc_debug_options ? gc_debug_options : "", env ? env : "");
3271 gboolean usage_printed = FALSE;
3273 opts = g_strsplit (debug_opts, ",", -1);
3274 for (ptr = opts; ptr && *ptr; ptr ++) {
3276 if (!strcmp (opt, ""))
3278 if (opt [0] >= '0' && opt [0] <= '9') {
3279 gc_debug_level = atoi (opt);
3284 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3285 gc_debug_file = fopen (rf, "wb");
3287 gc_debug_file = stderr;
3290 } else if (!strcmp (opt, "print-allowance")) {
3291 debug_print_allowance = TRUE;
3292 } else if (!strcmp (opt, "print-pinning")) {
3293 sgen_pin_stats_enable ();
3294 } else if (!strcmp (opt, "verify-before-allocs")) {
3295 verify_before_allocs = 1;
3296 has_per_allocation_action = TRUE;
3297 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3298 char *arg = strchr (opt, '=') + 1;
3299 verify_before_allocs = atoi (arg);
3300 has_per_allocation_action = TRUE;
3301 } else if (!strcmp (opt, "collect-before-allocs")) {
3302 collect_before_allocs = 1;
3303 has_per_allocation_action = TRUE;
3304 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3305 char *arg = strchr (opt, '=') + 1;
3306 has_per_allocation_action = TRUE;
3307 collect_before_allocs = atoi (arg);
3308 } else if (!strcmp (opt, "verify-before-collections")) {
3309 whole_heap_check_before_collection = TRUE;
3310 } else if (!strcmp (opt, "check-remset-consistency")) {
3311 remset_consistency_checks = TRUE;
3312 nursery_clear_policy = CLEAR_AT_GC;
3313 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3314 if (!major_collector.is_concurrent) {
3315 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3318 mod_union_consistency_check = TRUE;
3319 } else if (!strcmp (opt, "check-mark-bits")) {
3320 check_mark_bits_after_major_collection = TRUE;
3321 } else if (!strcmp (opt, "check-nursery-pinned")) {
3322 check_nursery_objects_pinned = TRUE;
3323 } else if (!strcmp (opt, "clear-at-gc")) {
3324 nursery_clear_policy = CLEAR_AT_GC;
3325 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3326 nursery_clear_policy = CLEAR_AT_GC;
3327 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3328 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3329 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3330 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3331 } else if (!strcmp (opt, "check-scan-starts")) {
3332 do_scan_starts_check = TRUE;
3333 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3334 do_verify_nursery = TRUE;
3335 } else if (!strcmp (opt, "check-concurrent")) {
3336 if (!major_collector.is_concurrent) {
3337 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3340 nursery_clear_policy = CLEAR_AT_GC;
3341 do_concurrent_checks = TRUE;
3342 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3343 do_dump_nursery_content = TRUE;
3344 } else if (!strcmp (opt, "disable-minor")) {
3345 disable_minor_collections = TRUE;
3346 } else if (!strcmp (opt, "disable-major")) {
3347 disable_major_collections = TRUE;
3348 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3349 char *filename = strchr (opt, '=') + 1;
3350 nursery_clear_policy = CLEAR_AT_GC;
3351 sgen_debug_enable_heap_dump (filename);
3352 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3353 char *filename = strchr (opt, '=') + 1;
3354 char *colon = strrchr (filename, ':');
3357 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3358 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3363 binary_protocol_init (filename, (long long)limit);
3364 } else if (!strcmp (opt, "nursery-canaries")) {
3365 do_verify_nursery = TRUE;
3366 enable_nursery_canaries = TRUE;
3367 } else if (!sgen_client_handle_gc_debug (opt)) {
3368 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3373 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);
3374 fprintf (stderr, "Valid <option>s are:\n");
3375 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3376 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3377 fprintf (stderr, " check-remset-consistency\n");
3378 fprintf (stderr, " check-mark-bits\n");
3379 fprintf (stderr, " check-nursery-pinned\n");
3380 fprintf (stderr, " verify-before-collections\n");
3381 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3382 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3383 fprintf (stderr, " disable-minor\n");
3384 fprintf (stderr, " disable-major\n");
3385 fprintf (stderr, " check-concurrent\n");
3386 fprintf (stderr, " clear-[nursery-]at-gc\n");
3387 fprintf (stderr, " clear-at-tlab-creation\n");
3388 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3389 fprintf (stderr, " check-scan-starts\n");
3390 fprintf (stderr, " print-allowance\n");
3391 fprintf (stderr, " print-pinning\n");
3392 fprintf (stderr, " heap-dump=<filename>\n");
3393 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3394 fprintf (stderr, " nursery-canaries\n");
3395 sgen_client_print_gc_debug_usage ();
3396 fprintf (stderr, "\n");
3398 usage_printed = TRUE;
3405 g_free (debug_opts);
3407 if (check_mark_bits_after_major_collection)
3408 nursery_clear_policy = CLEAR_AT_GC;
3410 if (major_collector.post_param_init)
3411 major_collector.post_param_init (&major_collector);
3413 if (major_collector.is_concurrent || sgen_minor_collector.is_parallel) {
3414 int num_workers = 1;
3415 if (major_collector.is_parallel || sgen_minor_collector.is_parallel) {
3416 /* FIXME Detect the number of physical cores, instead of logical */
3417 num_workers = mono_cpu_count () / 2;
3418 if (num_workers < 1)
3421 sgen_workers_init (num_workers, (SgenWorkerCallback) major_collector.worker_init_cb);
3424 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3426 memset (&remset, 0, sizeof (remset));
3428 sgen_card_table_init (&remset);
3430 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");
3434 sgen_init_bridge ();
3438 sgen_gc_initialized ()
3440 return gc_initialized > 0;
3444 sgen_get_nursery_clear_policy (void)
3446 return nursery_clear_policy;
3452 mono_coop_mutex_lock (&gc_mutex);
3456 sgen_gc_unlock (void)
3458 mono_coop_mutex_unlock (&gc_mutex);
3462 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3464 major_collector.iterate_live_block_ranges (callback);
3468 sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback)
3470 major_collector.iterate_block_ranges (callback);
3474 sgen_get_major_collector (void)
3476 return &major_collector;
3480 sgen_get_minor_collector (void)
3482 return &sgen_minor_collector;
3486 sgen_get_remset (void)
3492 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3494 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3495 sgen_los_count_cards (los_total, los_marked);
3498 static gboolean world_is_stopped = FALSE;
3500 /* LOCKING: assumes the GC lock is held */
3502 sgen_stop_world (int generation)
3504 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3506 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3508 binary_protocol_world_stopping (generation, sgen_timestamp (), (gpointer) (gsize) mono_native_thread_id_get ());
3510 sgen_client_stop_world (generation);
3512 world_is_stopped = TRUE;
3514 if (binary_protocol_is_heavy_enabled ())
3515 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3516 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3519 /* LOCKING: assumes the GC lock is held */
3521 sgen_restart_world (int generation)
3523 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3526 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3528 if (binary_protocol_is_heavy_enabled ())
3529 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3530 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3532 world_is_stopped = FALSE;
3534 sgen_client_restart_world (generation, &stw_time);
3536 binary_protocol_world_restarted (generation, sgen_timestamp ());
3538 if (sgen_client_bridge_need_processing ())
3539 sgen_client_bridge_processing_finish (generation);
3541 sgen_memgov_collection_end (generation, stw_time);
3545 sgen_is_world_stopped (void)
3547 return world_is_stopped;
3551 sgen_check_whole_heap_stw (void)
3553 sgen_stop_world (0);
3554 sgen_clear_nursery_fragments ();
3555 sgen_check_whole_heap (TRUE);
3556 sgen_restart_world (0);
3560 sgen_timestamp (void)
3562 SGEN_TV_DECLARE (timestamp);
3563 SGEN_TV_GETTIME (timestamp);
3564 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3567 #endif /* HAVE_SGEN_GC */