3 * Simple generational GC.
6 * Paolo Molaro (lupus@ximian.com)
7 * Rodrigo Kumpera (kumpera@gmail.com)
9 * Copyright 2005-2011 Novell, Inc (http://www.novell.com)
10 * Copyright 2011 Xamarin Inc (http://www.xamarin.com)
12 * Thread start/stop adapted from Boehm's GC:
13 * Copyright (c) 1994 by Xerox Corporation. All rights reserved.
14 * Copyright (c) 1996 by Silicon Graphics. All rights reserved.
15 * Copyright (c) 1998 by Fergus Henderson. All rights reserved.
16 * Copyright (c) 2000-2004 by Hewlett-Packard Company. All rights reserved.
17 * Copyright 2001-2003 Ximian, Inc
18 * Copyright 2003-2010 Novell, Inc.
19 * Copyright 2011 Xamarin, Inc.
20 * Copyright (C) 2012 Xamarin Inc
22 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
24 * Important: allocation provides always zeroed memory, having to do
25 * a memset after allocation is deadly for performance.
26 * Memory usage at startup is currently as follows:
28 * 64 KB internal space
30 * We should provide a small memory config with half the sizes
32 * We currently try to make as few mono assumptions as possible:
33 * 1) 2-word header with no GC pointers in it (first vtable, second to store the
35 * 2) gc descriptor is the second word in the vtable (first word in the class)
36 * 3) 8 byte alignment is the minimum and enough (not true for special structures (SIMD), FIXME)
37 * 4) there is a function to get an object's size and the number of
38 * elements in an array.
39 * 5) we know the special way bounds are allocated for complex arrays
40 * 6) we know about proxies and how to treat them when domains are unloaded
42 * Always try to keep stack usage to a minimum: no recursive behaviour
43 * and no large stack allocs.
45 * General description.
46 * Objects are initially allocated in a nursery using a fast bump-pointer technique.
47 * When the nursery is full we start a nursery collection: this is performed with a
49 * When the old generation is full we start a copying GC of the old generation as well:
50 * this will be changed to mark&sweep with copying when fragmentation becomes to severe
51 * in the future. Maybe we'll even do both during the same collection like IMMIX.
53 * The things that complicate this description are:
54 * *) pinned objects: we can't move them so we need to keep track of them
55 * *) no precise info of the thread stacks and registers: we need to be able to
56 * quickly find the objects that may be referenced conservatively and pin them
57 * (this makes the first issues more important)
58 * *) large objects are too expensive to be dealt with using copying GC: we handle them
59 * with mark/sweep during major collections
60 * *) some objects need to not move even if they are small (interned strings, Type handles):
61 * we use mark/sweep for them, too: they are not allocated in the nursery, but inside
62 * PinnedChunks regions
68 *) we could have a function pointer in MonoClass to implement
69 customized write barriers for value types
71 *) investigate the stuff needed to advance a thread to a GC-safe
72 point (single-stepping, read from unmapped memory etc) and implement it.
73 This would enable us to inline allocations and write barriers, for example,
74 or at least parts of them, like the write barrier checks.
75 We may need this also for handling precise info on stacks, even simple things
76 as having uninitialized data on the stack and having to wait for the prolog
77 to zero it. Not an issue for the last frame that we scan conservatively.
78 We could always not trust the value in the slots anyway.
80 *) modify the jit to save info about references in stack locations:
81 this can be done just for locals as a start, so that at least
82 part of the stack is handled precisely.
84 *) test/fix endianess issues
86 *) Implement a card table as the write barrier instead of remembered
87 sets? Card tables are not easy to implement with our current
88 memory layout. We have several different kinds of major heap
89 objects: Small objects in regular blocks, small objects in pinned
90 chunks and LOS objects. If we just have a pointer we have no way
91 to tell which kind of object it points into, therefore we cannot
92 know where its card table is. The least we have to do to make
93 this happen is to get rid of write barriers for indirect stores.
96 *) Get rid of write barriers for indirect stores. We can do this by
97 telling the GC to wbarrier-register an object once we do an ldloca
98 or ldelema on it, and to unregister it once it's not used anymore
99 (it can only travel downwards on the stack). The problem with
100 unregistering is that it needs to happen eventually no matter
101 what, even if exceptions are thrown, the thread aborts, etc.
102 Rodrigo suggested that we could do only the registering part and
103 let the collector find out (pessimistically) when it's safe to
104 unregister, namely when the stack pointer of the thread that
105 registered the object is higher than it was when the registering
106 happened. This might make for a good first implementation to get
107 some data on performance.
109 *) Some sort of blacklist support? Blacklists is a concept from the
110 Boehm GC: if during a conservative scan we find pointers to an
111 area which we might use as heap, we mark that area as unusable, so
112 pointer retention by random pinning pointers is reduced.
114 *) experiment with max small object size (very small right now - 2kb,
115 because it's tied to the max freelist size)
117 *) add an option to mmap the whole heap in one chunk: it makes for many
118 simplifications in the checks (put the nursery at the top and just use a single
119 check for inclusion/exclusion): the issue this has is that on 32 bit systems it's
120 not flexible (too much of the address space may be used by default or we can't
121 increase the heap as needed) and we'd need a race-free mechanism to return memory
122 back to the system (mprotect(PROT_NONE) will still keep the memory allocated if it
123 was written to, munmap is needed, but the following mmap may not find the same segment
126 *) memzero the major fragments after restarting the world and optionally a smaller
129 *) investigate having fragment zeroing threads
131 *) separate locks for finalization and other minor stuff to reduce
134 *) try a different copying order to improve memory locality
136 *) a thread abort after a store but before the write barrier will
137 prevent the write barrier from executing
139 *) specialized dynamically generated markers/copiers
141 *) Dynamically adjust TLAB size to the number of threads. If we have
142 too many threads that do allocation, we might need smaller TLABs,
143 and we might get better performance with larger TLABs if we only
144 have a handful of threads. We could sum up the space left in all
145 assigned TLABs and if that's more than some percentage of the
146 nursery size, reduce the TLAB size.
148 *) Explore placing unreachable objects on unused nursery memory.
149 Instead of memset'ng a region to zero, place an int[] covering it.
150 A good place to start is add_nursery_frag. The tricky thing here is
151 placing those objects atomically outside of a collection.
153 *) Allocation should use asymmetric Dekker synchronization:
154 http://blogs.oracle.com/dave/resource/Asymmetric-Dekker-Synchronization.txt
155 This should help weak consistency archs.
162 #define _XOPEN_SOURCE
163 #define _DARWIN_C_SOURCE
169 #ifdef HAVE_PTHREAD_H
172 #ifdef HAVE_PTHREAD_NP_H
173 #include <pthread_np.h>
181 #include "mono/sgen/sgen-gc.h"
182 #include "mono/sgen/sgen-cardtable.h"
183 #include "mono/sgen/sgen-protocol.h"
184 #include "mono/sgen/sgen-memory-governor.h"
185 #include "mono/sgen/sgen-hash-table.h"
186 #include "mono/sgen/sgen-pinning.h"
187 #include "mono/sgen/sgen-workers.h"
188 #include "mono/sgen/sgen-client.h"
189 #include "mono/sgen/sgen-pointer-queue.h"
190 #include "mono/sgen/gc-internal-agnostic.h"
191 #include "mono/utils/mono-proclib.h"
192 #include "mono/utils/mono-memory-model.h"
193 #include "mono/utils/hazard-pointer.h"
195 #include <mono/utils/memcheck.h>
196 #include <mono/utils/mono-mmap-internals.h>
198 #undef pthread_create
200 #undef pthread_detach
203 * ######################################################################
204 * ######## Types and constants used by the GC.
205 * ######################################################################
208 /* 0 means not initialized, 1 is initialized, -1 means in progress */
209 static int gc_initialized = 0;
210 /* If set, check if we need to do something every X allocations */
211 gboolean has_per_allocation_action;
212 /* If set, do a heap check every X allocation */
213 guint32 verify_before_allocs = 0;
214 /* If set, do a minor collection before every X allocation */
215 guint32 collect_before_allocs = 0;
216 /* If set, do a whole heap check before each collection */
217 static gboolean whole_heap_check_before_collection = FALSE;
218 /* If set, do a remset consistency check at various opportunities */
219 static gboolean remset_consistency_checks = FALSE;
220 /* If set, do a mod union consistency check before each finishing collection pause */
221 static gboolean mod_union_consistency_check = FALSE;
222 /* If set, check whether mark bits are consistent after major collections */
223 static gboolean check_mark_bits_after_major_collection = FALSE;
224 /* If set, check that all nursery objects are pinned/not pinned, depending on context */
225 static gboolean check_nursery_objects_pinned = FALSE;
226 /* If set, do a few checks when the concurrent collector is used */
227 static gboolean do_concurrent_checks = FALSE;
228 /* If set, do a plausibility check on the scan_starts before and after
230 static gboolean do_scan_starts_check = FALSE;
232 static gboolean disable_minor_collections = FALSE;
233 static gboolean disable_major_collections = FALSE;
234 static gboolean do_verify_nursery = FALSE;
235 static gboolean do_dump_nursery_content = FALSE;
236 static gboolean enable_nursery_canaries = FALSE;
238 static gboolean precleaning_enabled = TRUE;
239 static gboolean dynamic_nursery = FALSE;
240 static size_t min_nursery_size = 0;
241 static size_t max_nursery_size = 0;
243 #ifdef HEAVY_STATISTICS
244 guint64 stat_objects_alloced_degraded = 0;
245 guint64 stat_bytes_alloced_degraded = 0;
247 guint64 stat_copy_object_called_nursery = 0;
248 guint64 stat_objects_copied_nursery = 0;
249 guint64 stat_copy_object_called_major = 0;
250 guint64 stat_objects_copied_major = 0;
252 guint64 stat_scan_object_called_nursery = 0;
253 guint64 stat_scan_object_called_major = 0;
255 guint64 stat_slots_allocated_in_vain;
257 guint64 stat_nursery_copy_object_failed_from_space = 0;
258 guint64 stat_nursery_copy_object_failed_forwarded = 0;
259 guint64 stat_nursery_copy_object_failed_pinned = 0;
260 guint64 stat_nursery_copy_object_failed_to_space = 0;
262 static guint64 stat_wbarrier_add_to_global_remset = 0;
263 static guint64 stat_wbarrier_arrayref_copy = 0;
264 static guint64 stat_wbarrier_generic_store = 0;
265 static guint64 stat_wbarrier_generic_store_atomic = 0;
266 static guint64 stat_wbarrier_set_root = 0;
269 static guint64 stat_pinned_objects = 0;
271 static guint64 time_minor_pre_collection_fragment_clear = 0;
272 static guint64 time_minor_pinning = 0;
273 static guint64 time_minor_scan_remsets = 0;
274 static guint64 time_minor_scan_major_blocks = 0;
275 static guint64 time_minor_scan_los = 0;
276 static guint64 time_minor_scan_pinned = 0;
277 static guint64 time_minor_scan_roots = 0;
278 static guint64 time_minor_finish_gray_stack = 0;
279 static guint64 time_minor_fragment_creation = 0;
281 static guint64 time_major_pre_collection_fragment_clear = 0;
282 static guint64 time_major_pinning = 0;
283 static guint64 time_major_scan_pinned = 0;
284 static guint64 time_major_scan_roots = 0;
285 static guint64 time_major_scan_mod_union = 0;
286 static guint64 time_major_finish_gray_stack = 0;
287 static guint64 time_major_free_bigobjs = 0;
288 static guint64 time_major_los_sweep = 0;
289 static guint64 time_major_sweep = 0;
290 static guint64 time_major_fragment_creation = 0;
292 static guint64 time_max = 0;
294 static int sgen_max_pause_time = SGEN_DEFAULT_MAX_PAUSE_TIME;
295 static float sgen_max_pause_margin = SGEN_DEFAULT_MAX_PAUSE_MARGIN;
297 static SGEN_TV_DECLARE (time_major_conc_collection_start);
298 static SGEN_TV_DECLARE (time_major_conc_collection_end);
300 int gc_debug_level = 0;
302 static char* gc_params_options;
303 static char* gc_debug_options;
307 mono_gc_flush_info (void)
309 fflush (gc_debug_file);
313 #define TV_DECLARE SGEN_TV_DECLARE
314 #define TV_GETTIME SGEN_TV_GETTIME
315 #define TV_ELAPSED SGEN_TV_ELAPSED
317 static SGEN_TV_DECLARE (sgen_init_timestamp);
319 NurseryClearPolicy nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
321 #define object_is_forwarded SGEN_OBJECT_IS_FORWARDED
322 #define object_is_pinned SGEN_OBJECT_IS_PINNED
323 #define pin_object SGEN_PIN_OBJECT
325 #define ptr_in_nursery sgen_ptr_in_nursery
327 #define LOAD_VTABLE SGEN_LOAD_VTABLE
330 nursery_canaries_enabled (void)
332 return enable_nursery_canaries;
335 #define safe_object_get_size sgen_safe_object_get_size
337 #if defined(HAVE_CONC_GC_AS_DEFAULT)
338 /* Use concurrent major on deskstop platforms */
339 #define DEFAULT_MAJOR SGEN_MAJOR_CONCURRENT
341 #define DEFAULT_MAJOR SGEN_MAJOR_SERIAL
347 SGEN_MAJOR_CONCURRENT,
348 SGEN_MAJOR_CONCURRENT_PARALLEL
354 SGEN_MINOR_SIMPLE_PARALLEL,
361 SGEN_MODE_THROUGHPUT,
366 * ######################################################################
367 * ######## Global data.
368 * ######################################################################
370 MonoCoopMutex gc_mutex;
372 #define SCAN_START_SIZE SGEN_SCAN_START_SIZE
374 size_t degraded_mode = 0;
376 static mword bytes_pinned_from_failed_allocation = 0;
378 GCMemSection *nursery_section = NULL;
379 static volatile mword lowest_heap_address = ~(mword)0;
380 static volatile mword highest_heap_address = 0;
382 MonoCoopMutex sgen_interruption_mutex;
384 int current_collection_generation = -1;
385 volatile gboolean concurrent_collection_in_progress = FALSE;
387 /* objects that are ready to be finalized */
388 static SgenPointerQueue fin_ready_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
389 static SgenPointerQueue critical_fin_queue = SGEN_POINTER_QUEUE_INIT (INTERNAL_MEM_FINALIZE_READY);
391 /* registered roots: the key to the hash is the root start address */
393 * Different kinds of roots are kept separate to speed up pin_from_roots () for example.
395 SgenHashTable roots_hash [ROOT_TYPE_NUM] = {
396 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
397 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL),
398 SGEN_HASH_TABLE_INIT (INTERNAL_MEM_ROOTS_TABLE, INTERNAL_MEM_ROOT_RECORD, sizeof (RootRecord), sgen_aligned_addr_hash, NULL)
400 static mword roots_size = 0; /* amount of memory in the root set */
402 /* The size of a TLAB */
403 /* The bigger the value, the less often we have to go to the slow path to allocate a new
404 * one, but the more space is wasted by threads not allocating much memory.
406 * FIXME: Make this self-tuning for each thread.
408 guint32 tlab_size = (1024 * 4);
410 #define MAX_SMALL_OBJ_SIZE SGEN_MAX_SMALL_OBJ_SIZE
412 #define ALLOC_ALIGN SGEN_ALLOC_ALIGN
414 #define ALIGN_UP SGEN_ALIGN_UP
416 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
417 MonoNativeThreadId main_gc_thread = NULL;
420 /*Object was pinned during the current collection*/
421 static mword objects_pinned;
424 * ######################################################################
425 * ######## Macros and function declarations.
426 * ######################################################################
429 /* forward declarations */
430 static void scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx);
432 static void pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx);
433 static void finish_gray_stack (int generation, ScanCopyContext ctx);
436 SgenMajorCollector major_collector;
437 SgenMinorCollector sgen_minor_collector;
439 static SgenRememberedSet remset;
442 * The gray queue a worker job must use. If we're not parallel or
443 * concurrent, we use the main gray queue.
445 static SgenGrayQueue*
446 sgen_workers_get_job_gray_queue (WorkerData *worker_data, SgenGrayQueue *default_gray_queue)
449 return &worker_data->private_gray_queue;
450 SGEN_ASSERT (0, default_gray_queue, "Why don't we have a default gray queue when we're not running in a worker thread?");
451 return default_gray_queue;
455 gray_queue_redirect (SgenGrayQueue *queue)
457 sgen_workers_take_from_queue (current_collection_generation, queue);
461 sgen_scan_area_with_callback (char *start, char *end, IterateObjectCallbackFunc callback, void *data, gboolean allow_flags, gboolean fail_on_canaries)
463 while (start < end) {
467 if (!*(void**)start) {
468 start += sizeof (void*); /* should be ALLOC_ALIGN, really */
473 if (!(obj = (char *)SGEN_OBJECT_IS_FORWARDED (start)))
479 if (!sgen_client_object_is_array_fill ((GCObject*)obj)) {
480 CHECK_CANARY_FOR_OBJECT ((GCObject*)obj, fail_on_canaries);
481 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
482 callback ((GCObject*)obj, size, data);
483 CANARIFY_SIZE (size);
485 size = ALIGN_UP (safe_object_get_size ((GCObject*)obj));
493 * sgen_add_to_global_remset:
495 * The global remset contains locations which point into newspace after
496 * a minor collection. This can happen if the objects they point to are pinned.
498 * LOCKING: If called from a parallel collector, the global remset
499 * lock must be held. For serial collectors that is not necessary.
502 sgen_add_to_global_remset (gpointer ptr, GCObject *obj)
504 SGEN_ASSERT (5, sgen_ptr_in_nursery (obj), "Target pointer of global remset must be in the nursery");
506 HEAVY_STAT (++stat_wbarrier_add_to_global_remset);
508 if (!major_collector.is_concurrent) {
509 SGEN_ASSERT (5, current_collection_generation != -1, "Global remsets can only be added during collections");
511 if (current_collection_generation == -1)
512 SGEN_ASSERT (5, sgen_concurrent_collection_in_progress (), "Global remsets outside of collection pauses can only be added by the concurrent collector");
515 if (!object_is_pinned (obj))
516 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");
517 else if (sgen_cement_lookup_or_register (obj))
520 remset.record_pointer (ptr);
522 sgen_pin_stats_register_global_remset (obj);
524 SGEN_LOG (8, "Adding global remset for %p", ptr);
525 binary_protocol_global_remset (ptr, obj, (gpointer)SGEN_LOAD_VTABLE (obj));
529 * sgen_drain_gray_stack:
531 * Scan objects in the gray stack until the stack is empty. This should be called
532 * frequently after each object is copied, to achieve better locality and cache
537 sgen_drain_gray_stack (ScanCopyContext ctx)
539 SGEN_ASSERT (0, ctx.ops->drain_gray_stack, "Why do we have a scan/copy context with a missing drain gray stack function?");
541 return ctx.ops->drain_gray_stack (ctx.queue);
545 * Addresses in the pin queue are already sorted. This function finds
546 * the object header for each address and pins the object. The
547 * addresses must be inside the nursery section. The (start of the)
548 * address array is overwritten with the addresses of the actually
549 * pinned objects. Return the number of pinned objects.
552 pin_objects_from_nursery_pin_queue (gboolean do_scan_objects, ScanCopyContext ctx)
554 GCMemSection *section = nursery_section;
555 void **start = sgen_pinning_get_entry (section->pin_queue_first_entry);
556 void **end = sgen_pinning_get_entry (section->pin_queue_last_entry);
557 void *start_nursery = section->data;
558 void *end_nursery = section->end_data;
563 void *pinning_front = start_nursery;
565 void **definitely_pinned = start;
566 ScanObjectFunc scan_func = ctx.ops->scan_object;
567 SgenGrayQueue *queue = ctx.queue;
569 sgen_nursery_allocator_prepare_for_pinning ();
571 while (start < end) {
572 GCObject *obj_to_pin = NULL;
573 size_t obj_to_pin_size = 0;
578 SGEN_ASSERT (0, addr >= start_nursery && addr < end_nursery, "Potential pinning address out of range");
579 SGEN_ASSERT (0, addr >= last, "Pin queue not sorted");
586 SGEN_LOG (5, "Considering pinning addr %p", addr);
587 /* We've already processed everything up to pinning_front. */
588 if (addr < pinning_front) {
594 * Find the closest scan start <= addr. We might search backward in the
595 * scan_starts array because entries might be NULL. In the worst case we
596 * start at start_nursery.
598 idx = ((char*)addr - (char*)section->data) / SCAN_START_SIZE;
599 SGEN_ASSERT (0, idx < section->num_scan_start, "Scan start index out of range");
600 search_start = (void*)section->scan_starts [idx];
601 if (!search_start || search_start > addr) {
604 search_start = section->scan_starts [idx];
605 if (search_start && search_start <= addr)
608 if (!search_start || search_start > addr)
609 search_start = start_nursery;
613 * If the pinning front is closer than the scan start we found, start
614 * searching at the front.
616 if (search_start < pinning_front)
617 search_start = pinning_front;
620 * Now addr should be in an object a short distance from search_start.
622 * search_start must point to zeroed mem or point to an object.
625 size_t obj_size, canarified_obj_size;
628 if (!*(void**)search_start) {
629 search_start = (void*)ALIGN_UP ((mword)search_start + sizeof (gpointer));
630 /* The loop condition makes sure we don't overrun addr. */
634 canarified_obj_size = obj_size = ALIGN_UP (safe_object_get_size ((GCObject*)search_start));
637 * Filler arrays are marked by an invalid sync word. We don't
638 * consider them for pinning. They are not delimited by canaries,
641 if (!sgen_client_object_is_array_fill ((GCObject*)search_start)) {
642 CHECK_CANARY_FOR_OBJECT (search_start, TRUE);
643 CANARIFY_SIZE (canarified_obj_size);
645 if (addr >= search_start && (char*)addr < (char*)search_start + obj_size) {
646 /* This is the object we're looking for. */
647 obj_to_pin = (GCObject*)search_start;
648 obj_to_pin_size = canarified_obj_size;
653 /* Skip to the next object */
654 search_start = (void*)((char*)search_start + canarified_obj_size);
655 } while (search_start <= addr);
657 /* We've searched past the address we were looking for. */
659 pinning_front = search_start;
660 goto next_pin_queue_entry;
664 * We've found an object to pin. It might still be a dummy array, but we
665 * can advance the pinning front in any case.
667 pinning_front = (char*)obj_to_pin + obj_to_pin_size;
670 * If this is a dummy array marking the beginning of a nursery
671 * fragment, we don't pin it.
673 if (sgen_client_object_is_array_fill (obj_to_pin))
674 goto next_pin_queue_entry;
677 * Finally - pin the object!
679 desc = sgen_obj_get_descriptor_safe (obj_to_pin);
680 if (do_scan_objects) {
681 scan_func (obj_to_pin, desc, queue);
683 SGEN_LOG (4, "Pinned object %p, vtable %p (%s), count %d\n",
684 obj_to_pin, *(void**)obj_to_pin, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj_to_pin)), count);
685 binary_protocol_pin (obj_to_pin,
686 (gpointer)LOAD_VTABLE (obj_to_pin),
687 safe_object_get_size (obj_to_pin));
689 pin_object (obj_to_pin);
690 GRAY_OBJECT_ENQUEUE_SERIAL (queue, obj_to_pin, desc);
691 sgen_pin_stats_register_object (obj_to_pin, GENERATION_NURSERY);
692 definitely_pinned [count] = obj_to_pin;
695 if (concurrent_collection_in_progress)
696 sgen_pinning_register_pinned_in_nursery (obj_to_pin);
698 next_pin_queue_entry:
702 sgen_client_nursery_objects_pinned (definitely_pinned, count);
703 stat_pinned_objects += count;
708 pin_objects_in_nursery (gboolean do_scan_objects, ScanCopyContext ctx)
712 if (nursery_section->pin_queue_first_entry == nursery_section->pin_queue_last_entry)
715 reduced_to = pin_objects_from_nursery_pin_queue (do_scan_objects, ctx);
716 nursery_section->pin_queue_last_entry = nursery_section->pin_queue_first_entry + reduced_to;
720 * This function is only ever called (via `collector_pin_object()` in `sgen-copy-object.h`)
721 * when we can't promote an object because we're out of memory.
724 sgen_pin_object (GCObject *object, SgenGrayQueue *queue)
726 SGEN_ASSERT (0, sgen_ptr_in_nursery (object), "We're only supposed to use this for pinning nursery objects when out of memory.");
729 * All pinned objects are assumed to have been staged, so we need to stage as well.
730 * Also, the count of staged objects shows that "late pinning" happened.
732 sgen_pin_stage_ptr (object);
734 SGEN_PIN_OBJECT (object);
735 binary_protocol_pin (object, (gpointer)LOAD_VTABLE (object), safe_object_get_size (object));
738 sgen_pin_stats_register_object (object, GENERATION_NURSERY);
740 GRAY_OBJECT_ENQUEUE_SERIAL (queue, object, sgen_obj_get_descriptor_safe (object));
743 /* Sort the addresses in array in increasing order.
744 * Done using a by-the book heap sort. Which has decent and stable performance, is pretty cache efficient.
747 sgen_sort_addresses (void **array, size_t size)
752 for (i = 1; i < size; ++i) {
755 size_t parent = (child - 1) / 2;
757 if (array [parent] >= array [child])
760 tmp = array [parent];
761 array [parent] = array [child];
768 for (i = size - 1; i > 0; --i) {
771 array [i] = array [0];
777 while (root * 2 + 1 <= end) {
778 size_t child = root * 2 + 1;
780 if (child < end && array [child] < array [child + 1])
782 if (array [root] >= array [child])
786 array [root] = array [child];
795 * Scan the memory between start and end and queue values which could be pointers
796 * to the area between start_nursery and end_nursery for later consideration.
797 * Typically used for thread stacks.
800 sgen_conservatively_pin_objects_from (void **start, void **end, void *start_nursery, void *end_nursery, int pin_type)
804 SGEN_ASSERT (0, ((mword)start & (SIZEOF_VOID_P - 1)) == 0, "Why are we scanning for references in unaligned memory ?");
806 #if defined(VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE) && !defined(_WIN64)
807 VALGRIND_MAKE_MEM_DEFINED_IF_ADDRESSABLE (start, (char*)end - (char*)start);
810 while (start < end) {
812 * *start can point to the middle of an object
813 * note: should we handle pointing at the end of an object?
814 * pinning in C# code disallows pointing at the end of an object
815 * but there is some small chance that an optimizing C compiler
816 * may keep the only reference to an object by pointing
817 * at the end of it. We ignore this small chance for now.
818 * Pointers to the end of an object are indistinguishable
819 * from pointers to the start of the next object in memory
820 * so if we allow that we'd need to pin two objects...
821 * We queue the pointer in an array, the
822 * array will then be sorted and uniqued. This way
823 * we can coalesce several pinning pointers and it should
824 * be faster since we'd do a memory scan with increasing
825 * addresses. Note: we can align the address to the allocation
826 * alignment, so the unique process is more effective.
828 mword addr = (mword)*start;
829 addr &= ~(ALLOC_ALIGN - 1);
830 if (addr >= (mword)start_nursery && addr < (mword)end_nursery) {
831 SGEN_LOG (6, "Pinning address %p from %p", (void*)addr, start);
832 sgen_pin_stage_ptr ((void*)addr);
833 binary_protocol_pin_stage (start, (void*)addr);
834 sgen_pin_stats_register_address ((char*)addr, pin_type);
840 SGEN_LOG (7, "found %d potential pinned heap pointers", count);
844 * The first thing we do in a collection is to identify pinned objects.
845 * This function considers all the areas of memory that need to be
846 * conservatively scanned.
849 pin_from_roots (void *start_nursery, void *end_nursery, ScanCopyContext ctx)
853 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);
854 /* objects pinned from the API are inside these roots */
855 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_PINNED], void **, start_root, RootRecord *, root) {
856 SGEN_LOG (6, "Pinned roots %p-%p", start_root, root->end_root);
857 sgen_conservatively_pin_objects_from (start_root, (void**)root->end_root, start_nursery, end_nursery, PIN_TYPE_OTHER);
858 } SGEN_HASH_TABLE_FOREACH_END;
859 /* now deal with the thread stacks
860 * in the future we should be able to conservatively scan only:
861 * *) the cpu registers
862 * *) the unmanaged stack frames
863 * *) the _last_ managed stack frame
864 * *) pointers slots in managed frames
866 sgen_client_scan_thread_data (start_nursery, end_nursery, FALSE, ctx);
870 single_arg_user_copy_or_mark (GCObject **obj, void *gc_data)
872 ScanCopyContext *ctx = (ScanCopyContext *)gc_data;
873 ctx->ops->copy_or_mark_object (obj, ctx->queue);
877 * The memory area from start_root to end_root contains pointers to objects.
878 * Their position is precisely described by @desc (this means that the pointer
879 * can be either NULL or the pointer to the start of an object).
880 * This functions copies them to to_space updates them.
882 * This function is not thread-safe!
885 precisely_scan_objects_from (void** start_root, void** end_root, char* n_start, char *n_end, SgenDescriptor desc, ScanCopyContext ctx)
887 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
888 ScanPtrFieldFunc scan_field_func = ctx.ops->scan_ptr_field;
889 SgenGrayQueue *queue = ctx.queue;
891 switch (desc & ROOT_DESC_TYPE_MASK) {
892 case ROOT_DESC_BITMAP:
893 desc >>= ROOT_DESC_TYPE_SHIFT;
895 if ((desc & 1) && *start_root) {
896 copy_func ((GCObject**)start_root, queue);
897 SGEN_LOG (9, "Overwrote root at %p with %p", start_root, *start_root);
903 case ROOT_DESC_COMPLEX: {
904 gsize *bitmap_data = (gsize *)sgen_get_complex_descriptor_bitmap (desc);
905 gsize bwords = (*bitmap_data) - 1;
906 void **start_run = start_root;
908 while (bwords-- > 0) {
909 gsize bmap = *bitmap_data++;
910 void **objptr = start_run;
912 if ((bmap & 1) && *objptr) {
913 copy_func ((GCObject**)objptr, queue);
914 SGEN_LOG (9, "Overwrote root at %p with %p", objptr, *objptr);
919 start_run += GC_BITS_PER_WORD;
923 case ROOT_DESC_VECTOR: {
926 for (p = start_root; p < end_root; p++) {
928 scan_field_func (NULL, (GCObject**)p, queue);
932 case ROOT_DESC_USER: {
933 SgenUserRootMarkFunc marker = sgen_get_user_descriptor_func (desc);
934 marker (start_root, single_arg_user_copy_or_mark, &ctx);
937 case ROOT_DESC_RUN_LEN:
938 g_assert_not_reached ();
940 g_assert_not_reached ();
945 reset_heap_boundaries (void)
947 lowest_heap_address = ~(mword)0;
948 highest_heap_address = 0;
952 sgen_update_heap_boundaries (mword low, mword high)
957 old = lowest_heap_address;
960 } while (SGEN_CAS_PTR ((gpointer*)&lowest_heap_address, (gpointer)low, (gpointer)old) != (gpointer)old);
963 old = highest_heap_address;
966 } while (SGEN_CAS_PTR ((gpointer*)&highest_heap_address, (gpointer)high, (gpointer)old) != (gpointer)old);
970 * Allocate and setup the data structures needed to be able to allocate objects
971 * in the nursery. The nursery is stored in nursery_section.
974 alloc_nursery (gboolean dynamic, size_t min_size, size_t max_size)
981 min_size = SGEN_DEFAULT_NURSERY_MIN_SIZE;
983 max_size = SGEN_DEFAULT_NURSERY_MAX_SIZE;
985 SGEN_ASSERT (0, min_size == max_size, "We can't have nursery ranges for static configuration.");
987 min_size = max_size = SGEN_DEFAULT_NURSERY_SIZE;
990 SGEN_ASSERT (0, !nursery_section, "Why are we allocating the nursery twice?");
991 SGEN_LOG (2, "Allocating nursery size: %zu, initial %zu", max_size, min_size);
993 /* FIXME: handle OOM */
994 nursery_section = (GCMemSection *)sgen_alloc_internal (INTERNAL_MEM_SECTION);
996 /* If there isn't enough space even for the nursery we should simply abort. */
997 g_assert (sgen_memgov_try_alloc_space (max_size, SPACE_NURSERY));
1000 * The nursery section range represents the memory section where objects
1001 * can be found. This is used when iterating for objects in the nursery,
1002 * pinning etc. sgen_nursery_max_size represents the total allocated space
1003 * for the nursery. sgen_nursery_size represents the current size of the
1004 * nursery and it is used for allocation limits, heuristics etc. The
1005 * nursery section is not always identical to the current nursery size
1006 * because it can contain pinned objects from when the nursery was larger.
1008 * sgen_nursery_size <= nursery_section size <= sgen_nursery_max_size
1010 data = (char *)major_collector.alloc_heap (max_size, max_size);
1011 sgen_update_heap_boundaries ((mword)data, (mword)(data + max_size));
1012 nursery_section->data = data;
1013 nursery_section->end_data = data + min_size;
1014 scan_starts = (max_size + SCAN_START_SIZE - 1) / SCAN_START_SIZE;
1015 nursery_section->scan_starts = (char **)sgen_alloc_internal_dynamic (sizeof (char*) * scan_starts, INTERNAL_MEM_SCAN_STARTS, TRUE);
1016 nursery_section->num_scan_start = scan_starts;
1018 sgen_nursery_allocator_set_nursery_bounds (data, min_size, max_size);
1022 mono_gc_get_logfile (void)
1024 return gc_debug_file;
1028 mono_gc_params_set (const char* options)
1030 if (gc_params_options)
1031 g_free (gc_params_options);
1033 gc_params_options = g_strdup (options);
1037 mono_gc_debug_set (const char* options)
1039 if (gc_debug_options)
1040 g_free (gc_debug_options);
1042 gc_debug_options = g_strdup (options);
1046 scan_finalizer_entries (SgenPointerQueue *fin_queue, ScanCopyContext ctx)
1048 CopyOrMarkObjectFunc copy_func = ctx.ops->copy_or_mark_object;
1049 SgenGrayQueue *queue = ctx.queue;
1052 for (i = 0; i < fin_queue->next_slot; ++i) {
1053 GCObject *obj = (GCObject *)fin_queue->data [i];
1056 SGEN_LOG (5, "Scan of fin ready object: %p (%s)\n", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
1057 copy_func ((GCObject**)&fin_queue->data [i], queue);
1062 generation_name (int generation)
1064 switch (generation) {
1065 case GENERATION_NURSERY: return "nursery";
1066 case GENERATION_OLD: return "old";
1067 default: g_assert_not_reached ();
1072 sgen_generation_name (int generation)
1074 return generation_name (generation);
1078 finish_gray_stack (int generation, ScanCopyContext ctx)
1082 int done_with_ephemerons, ephemeron_rounds = 0;
1083 char *start_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_start () : NULL;
1084 char *end_addr = generation == GENERATION_NURSERY ? sgen_get_nursery_end () : (char*)-1;
1085 SgenGrayQueue *queue = ctx.queue;
1087 binary_protocol_finish_gray_stack_start (sgen_timestamp (), generation);
1089 * We copied all the reachable objects. Now it's the time to copy
1090 * the objects that were not referenced by the roots, but by the copied objects.
1091 * we built a stack of objects pointed to by gray_start: they are
1092 * additional roots and we may add more items as we go.
1093 * We loop until gray_start == gray_objects which means no more objects have
1094 * been added. Note this is iterative: no recursion is involved.
1095 * We need to walk the LO list as well in search of marked big objects
1096 * (use a flag since this is needed only on major collections). We need to loop
1097 * here as well, so keep a counter of marked LO (increasing it in copy_object).
1098 * To achieve better cache locality and cache usage, we drain the gray stack
1099 * frequently, after each object is copied, and just finish the work here.
1101 sgen_drain_gray_stack (ctx);
1103 SGEN_LOG (2, "%s generation done", generation_name (generation));
1106 Reset bridge data, we might have lingering data from a previous collection if this is a major
1107 collection trigged by minor overflow.
1109 We must reset the gathered bridges since their original block might be evacuated due to major
1110 fragmentation in the meanwhile and the bridge code should not have to deal with that.
1112 if (sgen_client_bridge_need_processing ())
1113 sgen_client_bridge_reset_data ();
1116 * Mark all strong toggleref objects. This must be done before we walk ephemerons or finalizers
1117 * to ensure they see the full set of live objects.
1119 sgen_client_mark_togglerefs (start_addr, end_addr, ctx);
1122 * Walk the ephemeron tables marking all values with reachable keys. This must be completely done
1123 * before processing finalizable objects and non-tracking weak links to avoid finalizing/clearing
1124 * objects that are in fact reachable.
1126 done_with_ephemerons = 0;
1128 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1129 sgen_drain_gray_stack (ctx);
1131 } while (!done_with_ephemerons);
1133 if (sgen_client_bridge_need_processing ()) {
1134 /*Make sure the gray stack is empty before we process bridge objects so we get liveness right*/
1135 sgen_drain_gray_stack (ctx);
1136 sgen_collect_bridge_objects (generation, ctx);
1137 if (generation == GENERATION_OLD)
1138 sgen_collect_bridge_objects (GENERATION_NURSERY, ctx);
1141 Do the first bridge step here, as the collector liveness state will become useless after that.
1143 An important optimization is to only proccess the possibly dead part of the object graph and skip
1144 over all live objects as we transitively know everything they point must be alive too.
1146 The above invariant is completely wrong if we let the gray queue be drained and mark/copy everything.
1148 This has the unfortunate side effect of making overflow collections perform the first step twice, but
1149 given we now have heuristics that perform major GC in anticipation of minor overflows this should not
1152 sgen_client_bridge_processing_stw_step ();
1156 Make sure we drain the gray stack before processing disappearing links and finalizers.
1157 If we don't make sure it is empty we might wrongly see a live object as dead.
1159 sgen_drain_gray_stack (ctx);
1162 We must clear weak links that don't track resurrection before processing object ready for
1163 finalization so they can be cleared before that.
1165 sgen_null_link_in_range (generation, ctx, FALSE);
1166 if (generation == GENERATION_OLD)
1167 sgen_null_link_in_range (GENERATION_NURSERY, ctx, FALSE);
1170 /* walk the finalization queue and move also the objects that need to be
1171 * finalized: use the finalized objects as new roots so the objects they depend
1172 * on are also not reclaimed. As with the roots above, only objects in the nursery
1173 * are marked/copied.
1175 sgen_finalize_in_range (generation, ctx);
1176 if (generation == GENERATION_OLD)
1177 sgen_finalize_in_range (GENERATION_NURSERY, ctx);
1178 /* drain the new stack that might have been created */
1179 SGEN_LOG (6, "Precise scan of gray area post fin");
1180 sgen_drain_gray_stack (ctx);
1183 * This must be done again after processing finalizable objects since CWL slots are cleared only after the key is finalized.
1185 done_with_ephemerons = 0;
1187 done_with_ephemerons = sgen_client_mark_ephemerons (ctx);
1188 sgen_drain_gray_stack (ctx);
1190 } while (!done_with_ephemerons);
1192 sgen_client_clear_unreachable_ephemerons (ctx);
1195 * We clear togglerefs only after all possible chances of revival are done.
1196 * This is semantically more inline with what users expect and it allows for
1197 * user finalizers to correctly interact with TR objects.
1199 sgen_client_clear_togglerefs (start_addr, end_addr, ctx);
1202 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);
1205 * handle disappearing links
1206 * Note we do this after checking the finalization queue because if an object
1207 * survives (at least long enough to be finalized) we don't clear the link.
1208 * This also deals with a possible issue with the monitor reclamation: with the Boehm
1209 * GC a finalized object my lose the monitor because it is cleared before the finalizer is
1212 g_assert (sgen_gray_object_queue_is_empty (queue));
1214 sgen_null_link_in_range (generation, ctx, TRUE);
1215 if (generation == GENERATION_OLD)
1216 sgen_null_link_in_range (GENERATION_NURSERY, ctx, TRUE);
1217 if (sgen_gray_object_queue_is_empty (queue))
1219 sgen_drain_gray_stack (ctx);
1222 g_assert (sgen_gray_object_queue_is_empty (queue));
1224 binary_protocol_finish_gray_stack_end (sgen_timestamp (), generation);
1228 sgen_check_section_scan_starts (GCMemSection *section)
1231 for (i = 0; i < section->num_scan_start; ++i) {
1232 if (section->scan_starts [i]) {
1233 mword size = safe_object_get_size ((GCObject*) section->scan_starts [i]);
1234 SGEN_ASSERT (0, size >= SGEN_CLIENT_MINIMUM_OBJECT_SIZE && size <= MAX_SMALL_OBJ_SIZE, "Weird object size at scan starts.");
1240 check_scan_starts (void)
1242 if (!do_scan_starts_check)
1244 sgen_check_section_scan_starts (nursery_section);
1245 major_collector.check_scan_starts ();
1249 scan_from_registered_roots (char *addr_start, char *addr_end, int root_type, ScanCopyContext ctx)
1253 SGEN_HASH_TABLE_FOREACH (&roots_hash [root_type], void **, start_root, RootRecord *, root) {
1254 SGEN_LOG (6, "Precise root scan %p-%p (desc: %p)", start_root, root->end_root, (void*)root->root_desc);
1255 precisely_scan_objects_from (start_root, (void**)root->end_root, addr_start, addr_end, root->root_desc, ctx);
1256 } SGEN_HASH_TABLE_FOREACH_END;
1262 static gboolean inited = FALSE;
1267 mono_counters_register ("Collection max time", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME | MONO_COUNTER_MONOTONIC, &time_max);
1269 mono_counters_register ("Minor fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pre_collection_fragment_clear);
1270 mono_counters_register ("Minor pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_pinning);
1271 mono_counters_register ("Minor scan remembered set", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_remsets);
1272 mono_counters_register ("Minor scan major blocks", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_major_blocks);
1273 mono_counters_register ("Minor scan los", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_los);
1274 mono_counters_register ("Minor scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_pinned);
1275 mono_counters_register ("Minor scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_scan_roots);
1276 mono_counters_register ("Minor fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_minor_fragment_creation);
1278 mono_counters_register ("Major fragment clear", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pre_collection_fragment_clear);
1279 mono_counters_register ("Major pinning", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_pinning);
1280 mono_counters_register ("Major scan pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_pinned);
1281 mono_counters_register ("Major scan roots", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_roots);
1282 mono_counters_register ("Major scan mod union", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_scan_mod_union);
1283 mono_counters_register ("Major finish gray stack", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_finish_gray_stack);
1284 mono_counters_register ("Major free big objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_free_bigobjs);
1285 mono_counters_register ("Major LOS sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_los_sweep);
1286 mono_counters_register ("Major sweep", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_sweep);
1287 mono_counters_register ("Major fragment creation", MONO_COUNTER_GC | MONO_COUNTER_ULONG | MONO_COUNTER_TIME, &time_major_fragment_creation);
1289 mono_counters_register ("Number of pinned objects", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_pinned_objects);
1291 #ifdef HEAVY_STATISTICS
1292 mono_counters_register ("WBarrier remember pointer", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_add_to_global_remset);
1293 mono_counters_register ("WBarrier arrayref copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_arrayref_copy);
1294 mono_counters_register ("WBarrier generic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store);
1295 mono_counters_register ("WBarrier generic atomic store called", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_generic_store_atomic);
1296 mono_counters_register ("WBarrier set root", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_wbarrier_set_root);
1298 mono_counters_register ("# objects allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_alloced_degraded);
1299 mono_counters_register ("bytes allocated degraded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_bytes_alloced_degraded);
1301 mono_counters_register ("# copy_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_nursery);
1302 mono_counters_register ("# objects copied (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_nursery);
1303 mono_counters_register ("# copy_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_copy_object_called_major);
1304 mono_counters_register ("# objects copied (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_objects_copied_major);
1306 mono_counters_register ("# scan_object() called (nursery)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_nursery);
1307 mono_counters_register ("# scan_object() called (major)", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_scan_object_called_major);
1309 mono_counters_register ("Slots allocated in vain", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_slots_allocated_in_vain);
1311 mono_counters_register ("# nursery copy_object() failed from space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_from_space);
1312 mono_counters_register ("# nursery copy_object() failed forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_forwarded);
1313 mono_counters_register ("# nursery copy_object() failed pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_pinned);
1314 mono_counters_register ("# nursery copy_object() failed to space", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_nursery_copy_object_failed_to_space);
1316 sgen_nursery_allocator_init_heavy_stats ();
1324 reset_pinned_from_failed_allocation (void)
1326 bytes_pinned_from_failed_allocation = 0;
1330 sgen_set_pinned_from_failed_allocation (mword objsize)
1332 bytes_pinned_from_failed_allocation += objsize;
1336 sgen_collection_is_concurrent (void)
1338 switch (current_collection_generation) {
1339 case GENERATION_NURSERY:
1341 case GENERATION_OLD:
1342 return concurrent_collection_in_progress;
1344 g_error ("Invalid current generation %d", current_collection_generation);
1350 sgen_concurrent_collection_in_progress (void)
1352 return concurrent_collection_in_progress;
1356 SgenThreadPoolJob job;
1357 SgenObjectOperations *ops;
1358 SgenGrayQueue *gc_thread_gray_queue;
1363 int job_index, job_split_count;
1366 static ScanCopyContext
1367 scan_copy_context_for_scan_job (void *worker_data_untyped, ScanJob *job)
1369 WorkerData *worker_data = (WorkerData *)worker_data_untyped;
1373 * For jobs enqueued on workers we set the ops at job runtime in order
1374 * to be able to profit from on the fly optimized object ops or other
1375 * object ops changes, like forced concurrent finish.
1377 SGEN_ASSERT (0, sgen_workers_is_worker_thread (mono_native_thread_id_get ()), "We need a context for the scan job");
1378 job->ops = sgen_workers_get_idle_func_object_ops (worker_data);
1381 return CONTEXT_FROM_OBJECT_OPERATIONS (job->ops, sgen_workers_get_job_gray_queue (worker_data, job->gc_thread_gray_queue));
1389 } ScanFromRegisteredRootsJob;
1392 job_scan_from_registered_roots (void *worker_data_untyped, SgenThreadPoolJob *job)
1394 ScanFromRegisteredRootsJob *job_data = (ScanFromRegisteredRootsJob*)job;
1395 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1397 scan_from_registered_roots (job_data->heap_start, job_data->heap_end, job_data->root_type, ctx);
1404 } ScanThreadDataJob;
1407 job_scan_thread_data (void *worker_data_untyped, SgenThreadPoolJob *job)
1409 ScanThreadDataJob *job_data = (ScanThreadDataJob*)job;
1410 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1412 sgen_client_scan_thread_data (job_data->heap_start, job_data->heap_end, TRUE, ctx);
1417 SgenPointerQueue *queue;
1418 } ScanFinalizerEntriesJob;
1421 job_scan_finalizer_entries (void *worker_data_untyped, SgenThreadPoolJob *job)
1423 ScanFinalizerEntriesJob *job_data = (ScanFinalizerEntriesJob*)job;
1424 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, &job_data->scan_job);
1426 scan_finalizer_entries (job_data->queue, ctx);
1430 job_scan_wbroots (void *worker_data_untyped, SgenThreadPoolJob *job)
1432 ScanJob *job_data = (ScanJob*)job;
1433 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1435 sgen_wbroots_scan_card_table (ctx);
1439 job_scan_major_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1441 SGEN_TV_DECLARE (atv);
1442 SGEN_TV_DECLARE (btv);
1443 ParallelScanJob *job_data = (ParallelScanJob*)job;
1444 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1446 SGEN_TV_GETTIME (atv);
1447 major_collector.scan_card_table (CARDTABLE_SCAN_GLOBAL, ctx, job_data->job_index, job_data->job_split_count);
1448 SGEN_TV_GETTIME (btv);
1449 time_minor_scan_major_blocks += SGEN_TV_ELAPSED (atv, btv);
1453 job_scan_los_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1455 SGEN_TV_DECLARE (atv);
1456 SGEN_TV_DECLARE (btv);
1457 ParallelScanJob *job_data = (ParallelScanJob*)job;
1458 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1460 SGEN_TV_GETTIME (atv);
1461 sgen_los_scan_card_table (CARDTABLE_SCAN_GLOBAL, ctx, job_data->job_index, job_data->job_split_count);
1462 SGEN_TV_GETTIME (btv);
1463 time_minor_scan_los += SGEN_TV_ELAPSED (atv, btv);
1467 job_scan_major_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1469 ParallelScanJob *job_data = (ParallelScanJob*)job;
1470 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1472 g_assert (concurrent_collection_in_progress);
1473 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, job_data->job_split_count);
1477 job_scan_los_mod_union_card_table (void *worker_data_untyped, SgenThreadPoolJob *job)
1479 ParallelScanJob *job_data = (ParallelScanJob*)job;
1480 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1482 g_assert (concurrent_collection_in_progress);
1483 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION, ctx, job_data->job_index, job_data->job_split_count);
1487 job_major_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1489 ParallelScanJob *job_data = (ParallelScanJob*)job;
1490 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1492 g_assert (concurrent_collection_in_progress);
1494 major_collector.scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, job_data->job_split_count);
1498 job_los_mod_union_preclean (void *worker_data_untyped, SgenThreadPoolJob *job)
1500 ParallelScanJob *job_data = (ParallelScanJob*)job;
1501 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, (ScanJob*)job_data);
1503 g_assert (concurrent_collection_in_progress);
1505 sgen_los_scan_card_table (CARDTABLE_SCAN_MOD_UNION_PRECLEAN, ctx, job_data->job_index, job_data->job_split_count);
1509 job_scan_last_pinned (void *worker_data_untyped, SgenThreadPoolJob *job)
1511 ScanJob *job_data = (ScanJob*)job;
1512 ScanCopyContext ctx = scan_copy_context_for_scan_job (worker_data_untyped, job_data);
1514 g_assert (concurrent_collection_in_progress);
1516 sgen_scan_pin_queue_objects (ctx);
1520 workers_finish_callback (void)
1522 ParallelScanJob *psj;
1524 int split_count = sgen_workers_get_job_split_count (GENERATION_OLD);
1526 /* Mod union preclean jobs */
1527 for (i = 0; i < split_count; i++) {
1528 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean major mod union cardtable", job_major_mod_union_preclean, sizeof (ParallelScanJob));
1529 psj->scan_job.gc_thread_gray_queue = NULL;
1531 psj->job_split_count = split_count;
1532 sgen_workers_enqueue_job (GENERATION_OLD, &psj->scan_job.job, TRUE);
1535 for (i = 0; i < split_count; i++) {
1536 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("preclean los mod union cardtable", job_los_mod_union_preclean, sizeof (ParallelScanJob));
1537 psj->scan_job.gc_thread_gray_queue = NULL;
1539 psj->job_split_count = split_count;
1540 sgen_workers_enqueue_job (GENERATION_OLD, &psj->scan_job.job, TRUE);
1543 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan last pinned", job_scan_last_pinned, sizeof (ScanJob));
1544 sj->gc_thread_gray_queue = NULL;
1545 sgen_workers_enqueue_job (GENERATION_OLD, &sj->job, TRUE);
1549 init_gray_queue (SgenGrayQueue *gc_thread_gray_queue)
1551 sgen_gray_object_queue_init (gc_thread_gray_queue, NULL, TRUE);
1555 enqueue_scan_remembered_set_jobs (SgenGrayQueue *gc_thread_gray_queue, SgenObjectOperations *ops, gboolean enqueue)
1557 int i, split_count = sgen_workers_get_job_split_count (GENERATION_NURSERY);
1560 sj = (ScanJob*)sgen_thread_pool_job_alloc ("scan wbroots", job_scan_wbroots, sizeof (ScanJob));
1562 sj->gc_thread_gray_queue = gc_thread_gray_queue;
1563 sgen_workers_enqueue_job (GENERATION_NURSERY, &sj->job, enqueue);
1565 for (i = 0; i < split_count; i++) {
1566 ParallelScanJob *psj;
1568 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan major remsets", job_scan_major_card_table, sizeof (ParallelScanJob));
1569 psj->scan_job.ops = ops;
1570 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1572 psj->job_split_count = split_count;
1573 sgen_workers_enqueue_job (GENERATION_NURSERY, &psj->scan_job.job, enqueue);
1575 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS remsets", job_scan_los_card_table, sizeof (ParallelScanJob));
1576 psj->scan_job.ops = ops;
1577 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1579 psj->job_split_count = split_count;
1580 sgen_workers_enqueue_job (GENERATION_NURSERY, &psj->scan_job.job, enqueue);
1585 enqueue_scan_from_roots_jobs (SgenGrayQueue *gc_thread_gray_queue, char *heap_start, char *heap_end, SgenObjectOperations *ops, gboolean enqueue)
1587 ScanFromRegisteredRootsJob *scrrj;
1588 ScanThreadDataJob *stdj;
1589 ScanFinalizerEntriesJob *sfej;
1591 /* registered roots, this includes static fields */
1593 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots normal", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1594 scrrj->scan_job.ops = ops;
1595 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1596 scrrj->heap_start = heap_start;
1597 scrrj->heap_end = heap_end;
1598 scrrj->root_type = ROOT_TYPE_NORMAL;
1599 sgen_workers_enqueue_job (current_collection_generation, &scrrj->scan_job.job, enqueue);
1601 if (current_collection_generation == GENERATION_OLD) {
1602 /* During minors we scan the cardtable for these roots instead */
1603 scrrj = (ScanFromRegisteredRootsJob*)sgen_thread_pool_job_alloc ("scan from registered roots wbarrier", job_scan_from_registered_roots, sizeof (ScanFromRegisteredRootsJob));
1604 scrrj->scan_job.ops = ops;
1605 scrrj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1606 scrrj->heap_start = heap_start;
1607 scrrj->heap_end = heap_end;
1608 scrrj->root_type = ROOT_TYPE_WBARRIER;
1609 sgen_workers_enqueue_job (current_collection_generation, &scrrj->scan_job.job, enqueue);
1614 stdj = (ScanThreadDataJob*)sgen_thread_pool_job_alloc ("scan thread data", job_scan_thread_data, sizeof (ScanThreadDataJob));
1615 stdj->scan_job.ops = ops;
1616 stdj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1617 stdj->heap_start = heap_start;
1618 stdj->heap_end = heap_end;
1619 sgen_workers_enqueue_job (current_collection_generation, &stdj->scan_job.job, enqueue);
1621 /* Scan the list of objects ready for finalization. */
1623 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1624 sfej->scan_job.ops = ops;
1625 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1626 sfej->queue = &fin_ready_queue;
1627 sgen_workers_enqueue_job (current_collection_generation, &sfej->scan_job.job, enqueue);
1629 sfej = (ScanFinalizerEntriesJob*)sgen_thread_pool_job_alloc ("scan critical finalizer entries", job_scan_finalizer_entries, sizeof (ScanFinalizerEntriesJob));
1630 sfej->scan_job.ops = ops;
1631 sfej->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
1632 sfej->queue = &critical_fin_queue;
1633 sgen_workers_enqueue_job (current_collection_generation, &sfej->scan_job.job, enqueue);
1637 * Perform a nursery collection.
1639 * Return whether any objects were late-pinned due to being out of memory.
1642 collect_nursery (const char *reason, gboolean is_overflow, SgenGrayQueue *unpin_queue)
1644 gboolean needs_major, is_parallel = FALSE;
1645 mword fragment_total;
1646 SgenGrayQueue gc_thread_gray_queue;
1647 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
1648 ScanCopyContext ctx;
1651 SGEN_TV_DECLARE (last_minor_collection_start_tv);
1652 SGEN_TV_DECLARE (last_minor_collection_end_tv);
1654 if (disable_minor_collections)
1657 TV_GETTIME (last_minor_collection_start_tv);
1658 atv = last_minor_collection_start_tv;
1660 binary_protocol_collection_begin (gc_stats.minor_gc_count, GENERATION_NURSERY);
1662 object_ops_nopar = sgen_concurrent_collection_in_progress ()
1663 ? &sgen_minor_collector.serial_ops_with_concurrent_major
1664 : &sgen_minor_collector.serial_ops;
1665 if (sgen_minor_collector.is_parallel && sgen_nursery_size >= SGEN_PARALLEL_MINOR_MIN_NURSERY_SIZE) {
1666 object_ops_par = sgen_concurrent_collection_in_progress ()
1667 ? &sgen_minor_collector.parallel_ops_with_concurrent_major
1668 : &sgen_minor_collector.parallel_ops;
1672 if (do_verify_nursery || do_dump_nursery_content)
1673 sgen_debug_verify_nursery (do_dump_nursery_content);
1675 current_collection_generation = GENERATION_NURSERY;
1677 SGEN_ASSERT (0, !sgen_collection_is_concurrent (), "Why is the nursery collection concurrent?");
1679 reset_pinned_from_failed_allocation ();
1681 check_scan_starts ();
1683 sgen_nursery_alloc_prepare_for_minor ();
1688 SGEN_LOG (1, "Start nursery collection %d %p-%p, size: %d", gc_stats.minor_gc_count, nursery_section->data, nursery_section->end_data, (int)(nursery_section->end_data - nursery_section->data));
1690 /* world must be stopped already */
1692 time_minor_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1694 sgen_client_pre_collection_checks ();
1696 major_collector.start_nursery_collection ();
1698 sgen_memgov_minor_collection_start ();
1700 init_gray_queue (&gc_thread_gray_queue);
1701 ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, &gc_thread_gray_queue);
1703 gc_stats.minor_gc_count ++;
1705 sgen_process_fin_stage_entries ();
1707 /* pin from pinned handles */
1708 sgen_init_pinning ();
1709 if (concurrent_collection_in_progress)
1710 sgen_init_pinning_for_conc ();
1711 sgen_client_binary_protocol_mark_start (GENERATION_NURSERY);
1712 pin_from_roots (nursery_section->data, nursery_section->end_data, ctx);
1713 /* pin cemented objects */
1714 sgen_pin_cemented_objects ();
1715 /* identify pinned objects */
1716 sgen_optimize_pin_queue ();
1717 sgen_pinning_setup_section (nursery_section);
1719 pin_objects_in_nursery (FALSE, ctx);
1720 sgen_pinning_trim_queue_to_section (nursery_section);
1721 if (concurrent_collection_in_progress)
1722 sgen_finish_pinning_for_conc ();
1724 if (remset_consistency_checks)
1725 sgen_check_remset_consistency ();
1727 if (whole_heap_check_before_collection) {
1728 sgen_clear_nursery_fragments ();
1729 sgen_check_whole_heap (FALSE);
1733 time_minor_pinning += TV_ELAPSED (btv, atv);
1734 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (btv, atv));
1735 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1737 remset.start_scan_remsets ();
1739 enqueue_scan_remembered_set_jobs (&gc_thread_gray_queue, is_parallel ? NULL : object_ops_nopar, is_parallel);
1741 /* we don't have complete write barrier yet, so we scan all the old generation sections */
1743 time_minor_scan_remsets += TV_ELAPSED (atv, btv);
1744 SGEN_LOG (2, "Old generation scan: %lld usecs", (long long)TV_ELAPSED (atv, btv));
1746 sgen_pin_stats_report ();
1748 /* FIXME: Why do we do this at this specific, seemingly random, point? */
1749 sgen_client_collecting_minor (&fin_ready_queue, &critical_fin_queue);
1752 time_minor_scan_pinned += TV_ELAPSED (btv, atv);
1754 enqueue_scan_from_roots_jobs (&gc_thread_gray_queue, nursery_section->data, nursery_section->end_data, is_parallel ? NULL : object_ops_nopar, is_parallel);
1757 gray_queue_redirect (&gc_thread_gray_queue);
1758 sgen_workers_start_all_workers (GENERATION_NURSERY, object_ops_nopar, object_ops_par, NULL);
1759 sgen_workers_join (GENERATION_NURSERY);
1763 time_minor_scan_roots += TV_ELAPSED (atv, btv);
1765 finish_gray_stack (GENERATION_NURSERY, ctx);
1768 time_minor_finish_gray_stack += TV_ELAPSED (btv, atv);
1769 sgen_client_binary_protocol_mark_end (GENERATION_NURSERY);
1771 if (objects_pinned) {
1772 sgen_optimize_pin_queue ();
1773 sgen_pinning_setup_section (nursery_section);
1777 * This is the latest point at which we can do this check, because
1778 * sgen_build_nursery_fragments() unpins nursery objects again.
1780 if (remset_consistency_checks)
1781 sgen_check_remset_consistency ();
1784 if (sgen_max_pause_time) {
1788 duration = (int)(TV_ELAPSED (last_minor_collection_start_tv, btv) / 10000);
1789 if (duration > (sgen_max_pause_time * sgen_max_pause_margin))
1790 sgen_resize_nursery (TRUE);
1792 sgen_resize_nursery (FALSE);
1794 sgen_resize_nursery (FALSE);
1797 /* walk the pin_queue, build up the fragment list of free memory, unmark
1798 * pinned objects as we go, memzero() the empty fragments so they are ready for the
1801 sgen_client_binary_protocol_reclaim_start (GENERATION_NURSERY);
1802 fragment_total = sgen_build_nursery_fragments (nursery_section, unpin_queue);
1803 if (!fragment_total)
1806 /* Clear TLABs for all threads */
1807 sgen_clear_tlabs ();
1809 sgen_client_binary_protocol_reclaim_end (GENERATION_NURSERY);
1811 time_minor_fragment_creation += TV_ELAPSED (atv, btv);
1812 SGEN_LOG (2, "Fragment creation: %lld usecs, %lu bytes available", (long long)TV_ELAPSED (atv, btv), (unsigned long)fragment_total);
1814 if (remset_consistency_checks)
1815 sgen_check_major_refs ();
1817 major_collector.finish_nursery_collection ();
1819 TV_GETTIME (last_minor_collection_end_tv);
1820 gc_stats.minor_gc_time += TV_ELAPSED (last_minor_collection_start_tv, last_minor_collection_end_tv);
1822 sgen_debug_dump_heap ("minor", gc_stats.minor_gc_count - 1, NULL);
1824 /* prepare the pin queue for the next collection */
1825 sgen_finish_pinning ();
1826 if (sgen_have_pending_finalizers ()) {
1827 SGEN_LOG (4, "Finalizer-thread wakeup");
1828 sgen_client_finalize_notify ();
1830 sgen_pin_stats_reset ();
1831 /* clear cemented hash */
1832 sgen_cement_clear_below_threshold ();
1834 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
1836 check_scan_starts ();
1838 binary_protocol_flush_buffers (FALSE);
1840 sgen_memgov_minor_collection_end (reason, is_overflow);
1842 /*objects are late pinned because of lack of memory, so a major is a good call*/
1843 needs_major = objects_pinned > 0;
1844 current_collection_generation = -1;
1847 binary_protocol_collection_end (gc_stats.minor_gc_count - 1, GENERATION_NURSERY, 0, 0);
1849 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1850 sgen_check_nursery_objects_pinned (unpin_queue != NULL);
1856 COPY_OR_MARK_FROM_ROOTS_SERIAL,
1857 COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT,
1858 COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT
1859 } CopyOrMarkFromRootsMode;
1862 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)
1867 /* FIXME: only use these values for the precise scan
1868 * note that to_space pointers should be excluded anyway...
1870 char *heap_start = NULL;
1871 char *heap_end = (char*)-1;
1872 ScanCopyContext ctx = CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue);
1873 gboolean concurrent = mode != COPY_OR_MARK_FROM_ROOTS_SERIAL;
1875 SGEN_ASSERT (0, !!concurrent == !!concurrent_collection_in_progress, "We've been called with the wrong mode.");
1877 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1878 /*This cleans up unused fragments */
1879 sgen_nursery_allocator_prepare_for_pinning ();
1881 if (do_concurrent_checks)
1882 sgen_debug_check_nursery_is_clean ();
1884 /* The concurrent collector doesn't touch the nursery. */
1885 sgen_nursery_alloc_prepare_for_major ();
1890 /* Pinning depends on this */
1891 sgen_clear_nursery_fragments ();
1893 if (whole_heap_check_before_collection)
1894 sgen_check_whole_heap (TRUE);
1897 time_major_pre_collection_fragment_clear += TV_ELAPSED (atv, btv);
1901 sgen_client_pre_collection_checks ();
1903 if (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1904 /* Remsets are not useful for a major collection */
1905 remset.clear_cards ();
1908 sgen_process_fin_stage_entries ();
1911 sgen_init_pinning ();
1912 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT)
1913 sgen_init_pinning_for_conc ();
1914 SGEN_LOG (6, "Collecting pinned addresses");
1915 pin_from_roots ((void*)lowest_heap_address, (void*)highest_heap_address, ctx);
1916 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1917 /* Pin cemented objects that were forced */
1918 sgen_pin_cemented_objects ();
1920 sgen_optimize_pin_queue ();
1921 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
1923 * Cemented objects that are in the pinned list will be marked. When
1924 * marking concurrently we won't mark mod-union cards for these objects.
1925 * Instead they will remain cemented until the next major collection,
1926 * when we will recheck if they are still pinned in the roots.
1928 sgen_cement_force_pinned ();
1931 sgen_client_collecting_major_1 ();
1934 * pin_queue now contains all candidate pointers, sorted and
1935 * uniqued. We must do two passes now to figure out which
1936 * objects are pinned.
1938 * The first is to find within the pin_queue the area for each
1939 * section. This requires that the pin_queue be sorted. We
1940 * also process the LOS objects and pinned chunks here.
1942 * The second, destructive, pass is to reduce the section
1943 * areas to pointers to the actually pinned objects.
1945 SGEN_LOG (6, "Pinning from sections");
1946 /* first pass for the sections */
1947 sgen_find_section_pin_queue_start_end (nursery_section);
1948 /* identify possible pointers to the insize of large objects */
1949 SGEN_LOG (6, "Pinning from large objects");
1950 for (bigobj = los_object_list; bigobj; bigobj = bigobj->next) {
1952 if (sgen_find_optimized_pin_queue_area ((char*)bigobj->data, (char*)bigobj->data + sgen_los_object_size (bigobj), &dummy, &dummy)) {
1953 binary_protocol_pin (bigobj->data, (gpointer)LOAD_VTABLE (bigobj->data), safe_object_get_size (bigobj->data));
1955 if (sgen_los_object_is_pinned (bigobj->data)) {
1956 SGEN_ASSERT (0, mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, "LOS objects can only be pinned here after concurrent marking.");
1959 sgen_los_pin_object (bigobj->data);
1960 if (SGEN_OBJECT_HAS_REFERENCES (bigobj->data))
1961 GRAY_OBJECT_ENQUEUE_SERIAL (gc_thread_gray_queue, bigobj->data, sgen_obj_get_descriptor ((GCObject*)bigobj->data));
1962 sgen_pin_stats_register_object (bigobj->data, GENERATION_OLD);
1963 SGEN_LOG (6, "Marked large object %p (%s) size: %lu from roots", bigobj->data,
1964 sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (bigobj->data)),
1965 (unsigned long)sgen_los_object_size (bigobj));
1967 sgen_client_pinned_los_object (bigobj->data);
1971 pin_objects_in_nursery (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT, ctx);
1972 if (check_nursery_objects_pinned && !sgen_minor_collector.is_split)
1973 sgen_check_nursery_objects_pinned (mode != COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT);
1975 major_collector.pin_objects (gc_thread_gray_queue);
1976 if (old_next_pin_slot)
1977 *old_next_pin_slot = sgen_get_pinned_count ();
1980 time_major_pinning += TV_ELAPSED (atv, btv);
1981 SGEN_LOG (2, "Finding pinned pointers: %zd in %lld usecs", sgen_get_pinned_count (), (long long)TV_ELAPSED (atv, btv));
1982 SGEN_LOG (4, "Start scan with %zd pinned objects", sgen_get_pinned_count ());
1984 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT)
1985 sgen_finish_pinning_for_conc ();
1987 major_collector.init_to_space ();
1989 SGEN_ASSERT (0, sgen_workers_all_done (), "Why are the workers not done when we start or finish a major collection?");
1990 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
1991 if (object_ops_par != NULL)
1992 sgen_workers_set_num_active_workers (GENERATION_OLD, 0);
1993 if (sgen_workers_have_idle_work (GENERATION_OLD)) {
1995 * We force the finish of the worker with the new object ops context
1996 * which can also do copying. We need to have finished pinning.
1998 sgen_workers_start_all_workers (GENERATION_OLD, object_ops_nopar, object_ops_par, NULL);
2000 sgen_workers_join (GENERATION_OLD);
2004 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2005 main_gc_thread = mono_native_thread_self ();
2008 sgen_client_collecting_major_2 ();
2011 time_major_scan_pinned += TV_ELAPSED (btv, atv);
2013 sgen_client_collecting_major_3 (&fin_ready_queue, &critical_fin_queue);
2015 enqueue_scan_from_roots_jobs (gc_thread_gray_queue, heap_start, heap_end, object_ops_nopar, FALSE);
2018 time_major_scan_roots += TV_ELAPSED (atv, btv);
2021 * We start the concurrent worker after pinning and after we scanned the roots
2022 * in order to make sure that the worker does not finish before handling all
2025 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
2026 sgen_workers_set_num_active_workers (GENERATION_OLD, 1);
2027 gray_queue_redirect (gc_thread_gray_queue);
2028 if (precleaning_enabled) {
2029 sgen_workers_start_all_workers (GENERATION_OLD, object_ops_nopar, object_ops_par, workers_finish_callback);
2031 sgen_workers_start_all_workers (GENERATION_OLD, object_ops_nopar, object_ops_par, NULL);
2035 if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
2036 int i, split_count = sgen_workers_get_job_split_count (GENERATION_OLD);
2037 gboolean parallel = object_ops_par != NULL;
2039 /* If we're not parallel we finish the collection on the gc thread */
2041 gray_queue_redirect (gc_thread_gray_queue);
2043 /* Mod union card table */
2044 for (i = 0; i < split_count; i++) {
2045 ParallelScanJob *psj;
2047 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan mod union cardtable", job_scan_major_mod_union_card_table, sizeof (ParallelScanJob));
2048 psj->scan_job.ops = parallel ? NULL : object_ops_nopar;
2049 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
2051 psj->job_split_count = split_count;
2052 sgen_workers_enqueue_job (GENERATION_OLD, &psj->scan_job.job, parallel);
2054 psj = (ParallelScanJob*)sgen_thread_pool_job_alloc ("scan LOS mod union cardtable", job_scan_los_mod_union_card_table, sizeof (ParallelScanJob));
2055 psj->scan_job.ops = parallel ? NULL : object_ops_nopar;
2056 psj->scan_job.gc_thread_gray_queue = gc_thread_gray_queue;
2058 psj->job_split_count = split_count;
2059 sgen_workers_enqueue_job (GENERATION_OLD, &psj->scan_job.job, parallel);
2064 * If we enqueue a job while workers are running we need to sgen_workers_ensure_awake
2065 * in order to make sure that we are running the idle func and draining all worker
2066 * gray queues. The operation of starting workers implies this, so we start them after
2067 * in order to avoid doing this operation twice. The workers will drain the main gray
2068 * stack that contained roots and pinned objects and also scan the mod union card
2071 sgen_workers_start_all_workers (GENERATION_OLD, object_ops_nopar, object_ops_par, NULL);
2072 sgen_workers_join (GENERATION_OLD);
2076 sgen_pin_stats_report ();
2078 if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
2079 sgen_finish_pinning ();
2081 sgen_pin_stats_reset ();
2083 if (do_concurrent_checks)
2084 sgen_debug_check_nursery_is_clean ();
2089 major_start_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean concurrent, size_t *old_next_pin_slot)
2091 SgenObjectOperations *object_ops_nopar, *object_ops_par = NULL;
2093 binary_protocol_collection_begin (gc_stats.major_gc_count, GENERATION_OLD);
2095 current_collection_generation = GENERATION_OLD;
2097 sgen_workers_assert_gray_queue_is_empty (GENERATION_OLD);
2100 sgen_cement_reset ();
2103 g_assert (major_collector.is_concurrent);
2104 concurrent_collection_in_progress = TRUE;
2106 object_ops_nopar = &major_collector.major_ops_concurrent_start;
2107 if (major_collector.is_parallel)
2108 object_ops_par = &major_collector.major_ops_conc_par_start;
2111 object_ops_nopar = &major_collector.major_ops_serial;
2114 reset_pinned_from_failed_allocation ();
2116 sgen_memgov_major_collection_start (concurrent, reason);
2118 //count_ref_nonref_objs ();
2119 //consistency_check ();
2121 check_scan_starts ();
2124 SGEN_LOG (1, "Start major collection %d", gc_stats.major_gc_count);
2125 gc_stats.major_gc_count ++;
2127 if (major_collector.start_major_collection)
2128 major_collector.start_major_collection ();
2130 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);
2134 major_finish_collection (SgenGrayQueue *gc_thread_gray_queue, const char *reason, gboolean is_overflow, size_t old_next_pin_slot, gboolean forced)
2136 ScannedObjectCounts counts;
2137 SgenObjectOperations *object_ops_nopar;
2138 mword fragment_total;
2144 if (concurrent_collection_in_progress) {
2145 SgenObjectOperations *object_ops_par = NULL;
2147 object_ops_nopar = &major_collector.major_ops_concurrent_finish;
2148 if (major_collector.is_parallel)
2149 object_ops_par = &major_collector.major_ops_conc_par_finish;
2151 major_copy_or_mark_from_roots (gc_thread_gray_queue, NULL, COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT, object_ops_nopar, object_ops_par);
2153 #ifdef SGEN_DEBUG_INTERNAL_ALLOC
2154 main_gc_thread = NULL;
2157 object_ops_nopar = &major_collector.major_ops_serial;
2160 sgen_workers_assert_gray_queue_is_empty (GENERATION_OLD);
2162 finish_gray_stack (GENERATION_OLD, CONTEXT_FROM_OBJECT_OPERATIONS (object_ops_nopar, gc_thread_gray_queue));
2164 time_major_finish_gray_stack += TV_ELAPSED (btv, atv);
2166 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after joining");
2168 if (objects_pinned) {
2169 g_assert (!concurrent_collection_in_progress);
2172 * This is slow, but we just OOM'd.
2174 * See comment at `sgen_pin_queue_clear_discarded_entries` for how the pin
2175 * queue is laid out at this point.
2177 sgen_pin_queue_clear_discarded_entries (nursery_section, old_next_pin_slot);
2179 * We need to reestablish all pinned nursery objects in the pin queue
2180 * because they're needed for fragment creation. Unpinning happens by
2181 * walking the whole queue, so it's not necessary to reestablish where major
2182 * heap block pins are - all we care is that they're still in there
2185 sgen_optimize_pin_queue ();
2186 sgen_find_section_pin_queue_start_end (nursery_section);
2190 reset_heap_boundaries ();
2191 sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
2193 /* walk the pin_queue, build up the fragment list of free memory, unmark
2194 * pinned objects as we go, memzero() the empty fragments so they are ready for the
2197 fragment_total = sgen_build_nursery_fragments (nursery_section, NULL);
2198 if (!fragment_total)
2200 SGEN_LOG (4, "Free space in nursery after major %ld", (long)fragment_total);
2202 if (do_concurrent_checks && concurrent_collection_in_progress)
2203 sgen_debug_check_nursery_is_clean ();
2205 /* prepare the pin queue for the next collection */
2206 sgen_finish_pinning ();
2208 /* Clear TLABs for all threads */
2209 sgen_clear_tlabs ();
2211 sgen_pin_stats_reset ();
2213 sgen_cement_clear_below_threshold ();
2215 if (check_mark_bits_after_major_collection)
2216 sgen_check_heap_marked (concurrent_collection_in_progress);
2219 time_major_fragment_creation += TV_ELAPSED (atv, btv);
2221 binary_protocol_sweep_begin (GENERATION_OLD, !major_collector.sweeps_lazily);
2222 sgen_memgov_major_pre_sweep ();
2225 time_major_free_bigobjs += TV_ELAPSED (btv, atv);
2230 time_major_los_sweep += TV_ELAPSED (atv, btv);
2232 major_collector.sweep ();
2234 binary_protocol_sweep_end (GENERATION_OLD, !major_collector.sweeps_lazily);
2237 time_major_sweep += TV_ELAPSED (btv, atv);
2239 sgen_debug_dump_heap ("major", gc_stats.major_gc_count - 1, reason);
2241 if (sgen_have_pending_finalizers ()) {
2242 SGEN_LOG (4, "Finalizer-thread wakeup");
2243 sgen_client_finalize_notify ();
2246 sgen_memgov_major_collection_end (forced, concurrent_collection_in_progress, reason, is_overflow);
2247 current_collection_generation = -1;
2249 memset (&counts, 0, sizeof (ScannedObjectCounts));
2250 major_collector.finish_major_collection (&counts);
2252 sgen_workers_assert_gray_queue_is_empty (GENERATION_OLD);
2254 SGEN_ASSERT (0, sgen_workers_all_done (), "Can't have workers working after major collection has finished");
2255 if (concurrent_collection_in_progress)
2256 concurrent_collection_in_progress = FALSE;
2258 check_scan_starts ();
2260 binary_protocol_flush_buffers (FALSE);
2262 //consistency_check ();
2264 binary_protocol_collection_end (gc_stats.major_gc_count - 1, GENERATION_OLD, counts.num_scanned_objects, counts.num_unique_scanned_objects);
2268 major_do_collection (const char *reason, gboolean is_overflow, gboolean forced)
2270 TV_DECLARE (time_start);
2271 TV_DECLARE (time_end);
2272 size_t old_next_pin_slot;
2273 SgenGrayQueue gc_thread_gray_queue;
2275 if (disable_major_collections)
2278 if (major_collector.get_and_reset_num_major_objects_marked) {
2279 long long num_marked = major_collector.get_and_reset_num_major_objects_marked ();
2280 g_assert (!num_marked);
2283 /* world must be stopped already */
2284 TV_GETTIME (time_start);
2286 init_gray_queue (&gc_thread_gray_queue);
2287 major_start_collection (&gc_thread_gray_queue, reason, FALSE, &old_next_pin_slot);
2288 major_finish_collection (&gc_thread_gray_queue, reason, is_overflow, old_next_pin_slot, forced);
2289 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2291 TV_GETTIME (time_end);
2292 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2294 /* FIXME: also report this to the user, preferably in gc-end. */
2295 if (major_collector.get_and_reset_num_major_objects_marked)
2296 major_collector.get_and_reset_num_major_objects_marked ();
2298 return bytes_pinned_from_failed_allocation > 0;
2302 major_start_concurrent_collection (const char *reason)
2304 TV_DECLARE (time_start);
2305 TV_DECLARE (time_end);
2306 long long num_objects_marked;
2307 SgenGrayQueue gc_thread_gray_queue;
2309 if (disable_major_collections)
2312 TV_GETTIME (time_start);
2313 SGEN_TV_GETTIME (time_major_conc_collection_start);
2315 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2316 g_assert (num_objects_marked == 0);
2318 binary_protocol_concurrent_start ();
2320 init_gray_queue (&gc_thread_gray_queue);
2321 // FIXME: store reason and pass it when finishing
2322 major_start_collection (&gc_thread_gray_queue, reason, TRUE, NULL);
2323 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2325 num_objects_marked = major_collector.get_and_reset_num_major_objects_marked ();
2327 TV_GETTIME (time_end);
2328 gc_stats.major_gc_time += TV_ELAPSED (time_start, time_end);
2330 current_collection_generation = -1;
2334 * Returns whether the major collection has finished.
2337 major_should_finish_concurrent_collection (void)
2339 return sgen_workers_all_done ();
2343 major_update_concurrent_collection (void)
2345 TV_DECLARE (total_start);
2346 TV_DECLARE (total_end);
2348 TV_GETTIME (total_start);
2350 binary_protocol_concurrent_update ();
2352 major_collector.update_cardtable_mod_union ();
2353 sgen_los_update_cardtable_mod_union ();
2355 TV_GETTIME (total_end);
2356 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2360 major_finish_concurrent_collection (gboolean forced)
2362 SgenGrayQueue gc_thread_gray_queue;
2363 TV_DECLARE (total_start);
2364 TV_DECLARE (total_end);
2366 TV_GETTIME (total_start);
2368 binary_protocol_concurrent_finish ();
2371 * We need to stop all workers since we're updating the cardtable below.
2372 * The workers will be resumed with a finishing pause context to avoid
2373 * additional cardtable and object scanning.
2375 sgen_workers_stop_all_workers (GENERATION_OLD);
2377 SGEN_TV_GETTIME (time_major_conc_collection_end);
2378 gc_stats.major_gc_time_concurrent += SGEN_TV_ELAPSED (time_major_conc_collection_start, time_major_conc_collection_end);
2380 major_collector.update_cardtable_mod_union ();
2381 sgen_los_update_cardtable_mod_union ();
2383 if (mod_union_consistency_check)
2384 sgen_check_mod_union_consistency ();
2386 current_collection_generation = GENERATION_OLD;
2387 sgen_cement_reset ();
2388 init_gray_queue (&gc_thread_gray_queue);
2389 major_finish_collection (&gc_thread_gray_queue, "finishing", FALSE, -1, forced);
2390 sgen_gray_object_queue_dispose (&gc_thread_gray_queue);
2392 TV_GETTIME (total_end);
2393 gc_stats.major_gc_time += TV_ELAPSED (total_start, total_end);
2395 current_collection_generation = -1;
2399 * Ensure an allocation request for @size will succeed by freeing enough memory.
2401 * LOCKING: The GC lock MUST be held.
2404 sgen_ensure_free_space (size_t size, int generation)
2406 int generation_to_collect = -1;
2407 const char *reason = NULL;
2409 if (generation == GENERATION_OLD) {
2410 if (sgen_need_major_collection (size)) {
2411 reason = "LOS overflow";
2412 generation_to_collect = GENERATION_OLD;
2415 if (degraded_mode) {
2416 if (sgen_need_major_collection (size)) {
2417 reason = "Degraded mode overflow";
2418 generation_to_collect = GENERATION_OLD;
2420 } else if (sgen_need_major_collection (size)) {
2421 reason = concurrent_collection_in_progress ? "Forced finish concurrent collection" : "Minor allowance";
2422 generation_to_collect = GENERATION_OLD;
2424 generation_to_collect = GENERATION_NURSERY;
2425 reason = "Nursery full";
2429 if (generation_to_collect == -1) {
2430 if (concurrent_collection_in_progress && sgen_workers_all_done ()) {
2431 generation_to_collect = GENERATION_OLD;
2432 reason = "Finish concurrent collection";
2436 if (generation_to_collect == -1)
2438 sgen_perform_collection (size, generation_to_collect, reason, FALSE, TRUE);
2442 * LOCKING: Assumes the GC lock is held.
2445 sgen_perform_collection (size_t requested_size, int generation_to_collect, const char *reason, gboolean wait_to_finish, gboolean stw)
2447 TV_DECLARE (gc_total_start);
2448 TV_DECLARE (gc_total_end);
2449 int overflow_generation_to_collect = -1;
2450 int oldest_generation_collected = generation_to_collect;
2451 const char *overflow_reason = NULL;
2452 gboolean finish_concurrent = concurrent_collection_in_progress && (major_should_finish_concurrent_collection () || generation_to_collect == GENERATION_OLD);
2454 binary_protocol_collection_requested (generation_to_collect, requested_size, wait_to_finish ? 1 : 0);
2456 SGEN_ASSERT (0, generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD, "What generation is this?");
2459 sgen_stop_world (generation_to_collect);
2461 SGEN_ASSERT (0, sgen_is_world_stopped (), "We can only collect if the world is stopped");
2464 TV_GETTIME (gc_total_start);
2466 // FIXME: extract overflow reason
2467 // FIXME: minor overflow for concurrent case
2468 if (generation_to_collect == GENERATION_NURSERY && !finish_concurrent) {
2469 if (concurrent_collection_in_progress)
2470 major_update_concurrent_collection ();
2472 if (collect_nursery (reason, FALSE, NULL) && !concurrent_collection_in_progress) {
2473 overflow_generation_to_collect = GENERATION_OLD;
2474 overflow_reason = "Minor overflow";
2476 } else if (finish_concurrent) {
2477 major_finish_concurrent_collection (wait_to_finish);
2478 oldest_generation_collected = GENERATION_OLD;
2480 SGEN_ASSERT (0, generation_to_collect == GENERATION_OLD, "We should have handled nursery collections above");
2481 if (major_collector.is_concurrent && !wait_to_finish) {
2482 collect_nursery ("Concurrent start", FALSE, NULL);
2483 major_start_concurrent_collection (reason);
2484 oldest_generation_collected = GENERATION_NURSERY;
2485 } else if (major_do_collection (reason, FALSE, wait_to_finish)) {
2486 overflow_generation_to_collect = GENERATION_NURSERY;
2487 overflow_reason = "Excessive pinning";
2491 if (overflow_generation_to_collect != -1) {
2492 SGEN_ASSERT (0, !concurrent_collection_in_progress, "We don't yet support overflow collections with the concurrent collector");
2495 * We need to do an overflow collection, either because we ran out of memory
2496 * or the nursery is fully pinned.
2499 if (overflow_generation_to_collect == GENERATION_NURSERY)
2500 collect_nursery (overflow_reason, TRUE, NULL);
2502 major_do_collection (overflow_reason, TRUE, wait_to_finish);
2504 oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
2507 SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)sgen_gc_get_total_heap_allocation (), (unsigned long)los_memory_usage);
2509 /* this also sets the proper pointers for the next allocation */
2510 if (generation_to_collect == GENERATION_NURSERY && !sgen_can_alloc_size (requested_size)) {
2511 /* TypeBuilder and MonoMethod are killing mcs with fragmentation */
2512 SGEN_LOG (1, "nursery collection didn't find enough room for %zd alloc (%zd pinned)", requested_size, sgen_get_pinned_count ());
2513 sgen_dump_pin_queue ();
2517 TV_GETTIME (gc_total_end);
2518 time_max = MAX (time_max, TV_ELAPSED (gc_total_start, gc_total_end));
2521 sgen_restart_world (oldest_generation_collected);
2525 * ######################################################################
2526 * ######## Memory allocation from the OS
2527 * ######################################################################
2528 * This section of code deals with getting memory from the OS and
2529 * allocating memory for GC-internal data structures.
2530 * Internal memory can be handled with a freelist for small objects.
2536 G_GNUC_UNUSED static void
2537 report_internal_mem_usage (void)
2539 printf ("Internal memory usage:\n");
2540 sgen_report_internal_mem_usage ();
2541 printf ("Pinned memory usage:\n");
2542 major_collector.report_pinned_memory_usage ();
2546 * ######################################################################
2547 * ######## Finalization support
2548 * ######################################################################
2552 * If the object has been forwarded it means it's still referenced from a root.
2553 * If it is pinned it's still alive as well.
2554 * A LOS object is only alive if we have pinned it.
2555 * Return TRUE if @obj is ready to be finalized.
2557 static inline gboolean
2558 sgen_is_object_alive (GCObject *object)
2560 if (ptr_in_nursery (object))
2561 return sgen_nursery_is_object_alive (object);
2563 return sgen_major_is_object_alive (object);
2567 * This function returns true if @object is either alive and belongs to the
2568 * current collection - major collections are full heap, so old gen objects
2569 * are never alive during a minor collection.
2572 sgen_is_object_alive_and_on_current_collection (GCObject *object)
2574 if (ptr_in_nursery (object))
2575 return sgen_nursery_is_object_alive (object);
2577 if (current_collection_generation == GENERATION_NURSERY)
2580 return sgen_major_is_object_alive (object);
2585 sgen_gc_is_object_ready_for_finalization (GCObject *object)
2587 return !sgen_is_object_alive (object);
2591 sgen_queue_finalization_entry (GCObject *obj)
2593 gboolean critical = sgen_client_object_has_critical_finalizer (obj);
2595 sgen_pointer_queue_add (critical ? &critical_fin_queue : &fin_ready_queue, obj);
2597 sgen_client_object_queued_for_finalization (obj);
2601 sgen_object_is_live (GCObject *obj)
2603 return sgen_is_object_alive_and_on_current_collection (obj);
2607 * `System.GC.WaitForPendingFinalizers` first checks `sgen_have_pending_finalizers()` to
2608 * determine whether it can exit quickly. The latter must therefore only return FALSE if
2609 * all finalizers have really finished running.
2611 * `sgen_gc_invoke_finalizers()` first dequeues a finalizable object, and then finalizes it.
2612 * This means that just checking whether the queues are empty leaves the possibility that an
2613 * object might have been dequeued but not yet finalized. That's why we need the additional
2614 * flag `pending_unqueued_finalizer`.
2617 static volatile gboolean pending_unqueued_finalizer = FALSE;
2618 volatile gboolean sgen_suspend_finalizers = FALSE;
2621 sgen_set_suspend_finalizers (void)
2623 sgen_suspend_finalizers = TRUE;
2627 sgen_gc_invoke_finalizers (void)
2631 g_assert (!pending_unqueued_finalizer);
2633 /* FIXME: batch to reduce lock contention */
2634 while (sgen_have_pending_finalizers ()) {
2640 * We need to set `pending_unqueued_finalizer` before dequeing the
2641 * finalizable object.
2643 if (!sgen_pointer_queue_is_empty (&fin_ready_queue)) {
2644 pending_unqueued_finalizer = TRUE;
2645 mono_memory_write_barrier ();
2646 obj = (GCObject *)sgen_pointer_queue_pop (&fin_ready_queue);
2647 } else if (!sgen_pointer_queue_is_empty (&critical_fin_queue)) {
2648 pending_unqueued_finalizer = TRUE;
2649 mono_memory_write_barrier ();
2650 obj = (GCObject *)sgen_pointer_queue_pop (&critical_fin_queue);
2656 SGEN_LOG (7, "Finalizing object %p (%s)", obj, sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (obj)));
2664 /* the object is on the stack so it is pinned */
2665 /*g_print ("Calling finalizer for object: %p (%s)\n", obj, sgen_client_object_safe_name (obj));*/
2666 sgen_client_run_finalize (obj);
2669 if (pending_unqueued_finalizer) {
2670 mono_memory_write_barrier ();
2671 pending_unqueued_finalizer = FALSE;
2678 sgen_have_pending_finalizers (void)
2680 if (sgen_suspend_finalizers)
2682 return pending_unqueued_finalizer || !sgen_pointer_queue_is_empty (&fin_ready_queue) || !sgen_pointer_queue_is_empty (&critical_fin_queue);
2686 * ######################################################################
2687 * ######## registered roots support
2688 * ######################################################################
2692 * We do not coalesce roots.
2695 sgen_register_root (char *start, size_t size, SgenDescriptor descr, int root_type, int source, const char *msg)
2697 RootRecord new_root;
2700 for (i = 0; i < ROOT_TYPE_NUM; ++i) {
2701 RootRecord *root = (RootRecord *)sgen_hash_table_lookup (&roots_hash [i], start);
2702 /* we allow changing the size and the descriptor (for thread statics etc) */
2704 size_t old_size = root->end_root - start;
2705 root->end_root = start + size;
2706 SGEN_ASSERT (0, !!root->root_desc == !!descr, "Can't change whether a root is precise or conservative.");
2707 SGEN_ASSERT (0, root->source == source, "Can't change a root's source identifier.");
2708 SGEN_ASSERT (0, !!root->msg == !!msg, "Can't change a root's message.");
2709 root->root_desc = descr;
2711 roots_size -= old_size;
2717 new_root.end_root = start + size;
2718 new_root.root_desc = descr;
2719 new_root.source = source;
2722 sgen_hash_table_replace (&roots_hash [root_type], start, &new_root, NULL);
2725 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);
2732 sgen_deregister_root (char* addr)
2738 for (root_type = 0; root_type < ROOT_TYPE_NUM; ++root_type) {
2739 if (sgen_hash_table_remove (&roots_hash [root_type], addr, &root))
2740 roots_size -= (root.end_root - addr);
2746 sgen_wbroots_iterate_live_block_ranges (sgen_cardtable_block_callback cb)
2750 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_WBARRIER], void **, start_root, RootRecord *, root) {
2751 cb ((mword)start_root, (mword)root->end_root - (mword)start_root);
2752 } SGEN_HASH_TABLE_FOREACH_END;
2755 /* Root equivalent of sgen_client_cardtable_scan_object */
2757 sgen_wbroot_scan_card_table (void** start_root, mword size, ScanCopyContext ctx)
2759 ScanPtrFieldFunc scan_field_func = ctx.ops->scan_ptr_field;
2760 guint8 *card_data = sgen_card_table_get_card_scan_address ((mword)start_root);
2761 guint8 *card_base = card_data;
2762 mword card_count = sgen_card_table_number_of_cards_in_range ((mword)start_root, size);
2763 guint8 *card_data_end = card_data + card_count;
2764 mword extra_idx = 0;
2765 char *obj_start = sgen_card_table_align_pointer (start_root);
2766 char *obj_end = (char*)start_root + size;
2767 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2768 guint8 *overflow_scan_end = NULL;
2771 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2772 /*Check for overflow and if so, setup to scan in two steps*/
2773 if (card_data_end >= SGEN_SHADOW_CARDTABLE_END) {
2774 overflow_scan_end = sgen_shadow_cardtable + (card_data_end - SGEN_SHADOW_CARDTABLE_END);
2775 card_data_end = SGEN_SHADOW_CARDTABLE_END;
2781 card_data = sgen_find_next_card (card_data, card_data_end);
2783 for (; card_data < card_data_end; card_data = sgen_find_next_card (card_data + 1, card_data_end)) {
2784 size_t idx = (card_data - card_base) + extra_idx;
2785 char *start = (char*)(obj_start + idx * CARD_SIZE_IN_BYTES);
2786 char *card_end = start + CARD_SIZE_IN_BYTES;
2787 char *elem = start, *first_elem = start;
2790 * Don't clean first and last card on 32bit systems since they
2791 * may also be part from other roots.
2793 if (card_data != card_base && card_data != (card_data_end - 1))
2794 sgen_card_table_prepare_card_for_scanning (card_data);
2796 card_end = MIN (card_end, obj_end);
2798 if (elem < (char*)start_root)
2799 first_elem = elem = (char*)start_root;
2801 for (; elem < card_end; elem += SIZEOF_VOID_P) {
2802 if (*(GCObject**)elem)
2803 scan_field_func (NULL, (GCObject**)elem, ctx.queue);
2806 binary_protocol_card_scan (first_elem, elem - first_elem);
2809 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2810 if (overflow_scan_end) {
2811 extra_idx = card_data - card_base;
2812 card_base = card_data = sgen_shadow_cardtable;
2813 card_data_end = overflow_scan_end;
2814 overflow_scan_end = NULL;
2821 sgen_wbroots_scan_card_table (ScanCopyContext ctx)
2826 SGEN_HASH_TABLE_FOREACH (&roots_hash [ROOT_TYPE_WBARRIER], void **, start_root, RootRecord *, root) {
2827 SGEN_ASSERT (0, (root->root_desc & ROOT_DESC_TYPE_MASK) == ROOT_DESC_VECTOR, "Unsupported root type");
2829 sgen_wbroot_scan_card_table (start_root, (mword)root->end_root - (mword)start_root, ctx);
2830 } SGEN_HASH_TABLE_FOREACH_END;
2834 * ######################################################################
2835 * ######## Thread handling (stop/start code)
2836 * ######################################################################
2840 sgen_get_current_collection_generation (void)
2842 return current_collection_generation;
2846 sgen_thread_attach (SgenThreadInfo* info)
2848 info->tlab_start = info->tlab_next = info->tlab_temp_end = info->tlab_real_end = NULL;
2850 sgen_client_thread_attach (info);
2856 sgen_thread_detach_with_lock (SgenThreadInfo *p)
2858 sgen_client_thread_detach_with_lock (p);
2862 * ######################################################################
2863 * ######## Write barriers
2864 * ######################################################################
2868 * Note: the write barriers first do the needed GC work and then do the actual store:
2869 * this way the value is visible to the conservative GC scan after the write barrier
2870 * itself. If a GC interrupts the barrier in the middle, value will be kept alive by
2871 * the conservative scan, otherwise by the remembered set scan.
2875 * mono_gc_wbarrier_arrayref_copy:
2878 mono_gc_wbarrier_arrayref_copy (gpointer dest_ptr, gpointer src_ptr, int count)
2880 HEAVY_STAT (++stat_wbarrier_arrayref_copy);
2881 /*This check can be done without taking a lock since dest_ptr array is pinned*/
2882 if (ptr_in_nursery (dest_ptr) || count <= 0) {
2883 mono_gc_memmove_aligned (dest_ptr, src_ptr, count * sizeof (gpointer));
2887 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2888 if (binary_protocol_is_heavy_enabled ()) {
2890 for (i = 0; i < count; ++i) {
2891 gpointer dest = (gpointer*)dest_ptr + i;
2892 gpointer obj = *((gpointer*)src_ptr + i);
2894 binary_protocol_wbarrier (dest, obj, (gpointer)LOAD_VTABLE (obj));
2899 remset.wbarrier_arrayref_copy (dest_ptr, src_ptr, count);
2903 * mono_gc_wbarrier_generic_nostore:
2906 mono_gc_wbarrier_generic_nostore (gpointer ptr)
2910 HEAVY_STAT (++stat_wbarrier_generic_store);
2912 sgen_client_wbarrier_generic_nostore_check (ptr);
2914 obj = *(gpointer*)ptr;
2916 binary_protocol_wbarrier (ptr, obj, (gpointer)LOAD_VTABLE (obj));
2919 * We need to record old->old pointer locations for the
2920 * concurrent collector.
2922 if (!ptr_in_nursery (obj) && !concurrent_collection_in_progress) {
2923 SGEN_LOG (8, "Skipping remset at %p", ptr);
2927 SGEN_LOG (8, "Adding remset at %p", ptr);
2929 remset.wbarrier_generic_nostore (ptr);
2933 * mono_gc_wbarrier_generic_store:
2936 mono_gc_wbarrier_generic_store (gpointer ptr, GCObject* value)
2938 SGEN_LOG (8, "Wbarrier store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2939 SGEN_UPDATE_REFERENCE_ALLOW_NULL (ptr, value);
2940 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2941 mono_gc_wbarrier_generic_nostore (ptr);
2942 sgen_dummy_use (value);
2946 * mono_gc_wbarrier_generic_store_atomic:
2947 * Same as \c mono_gc_wbarrier_generic_store but performs the store
2948 * as an atomic operation with release semantics.
2951 mono_gc_wbarrier_generic_store_atomic (gpointer ptr, GCObject *value)
2953 HEAVY_STAT (++stat_wbarrier_generic_store_atomic);
2955 SGEN_LOG (8, "Wbarrier atomic store at %p to %p (%s)", ptr, value, value ? sgen_client_vtable_get_name (SGEN_LOAD_VTABLE (value)) : "null");
2957 InterlockedWritePointer ((volatile gpointer *)ptr, value);
2959 if (ptr_in_nursery (value) || concurrent_collection_in_progress)
2960 mono_gc_wbarrier_generic_nostore (ptr);
2962 sgen_dummy_use (value);
2966 sgen_wbarrier_range_copy (gpointer _dest, gpointer _src, int size)
2968 remset.wbarrier_range_copy (_dest,_src, size);
2972 * ######################################################################
2973 * ######## Other mono public interface functions.
2974 * ######################################################################
2978 sgen_gc_collect (int generation)
2983 sgen_perform_collection (0, generation, "user request", TRUE, TRUE);
2988 sgen_gc_collection_count (int generation)
2990 if (generation == 0)
2991 return gc_stats.minor_gc_count;
2992 return gc_stats.major_gc_count;
2996 sgen_gc_get_used_size (void)
3000 tot = los_memory_usage;
3001 tot += nursery_section->end_data - nursery_section->data;
3002 tot += major_collector.get_used_size ();
3003 /* FIXME: account for pinned objects */
3009 sgen_env_var_error (const char *env_var, const char *fallback, const char *description_format, ...)
3013 va_start (ap, description_format);
3015 fprintf (stderr, "Warning: In environment variable `%s': ", env_var);
3016 vfprintf (stderr, description_format, ap);
3018 fprintf (stderr, " - %s", fallback);
3019 fprintf (stderr, "\n");
3025 parse_double_in_interval (const char *env_var, const char *opt_name, const char *opt, double min, double max, double *result)
3028 double val = strtod (opt, &endptr);
3029 if (endptr == opt) {
3030 sgen_env_var_error (env_var, "Using default value.", "`%s` must be a number.", opt_name);
3033 else if (val < min || val > max) {
3034 sgen_env_var_error (env_var, "Using default value.", "`%s` must be between %.2f - %.2f.", opt_name, min, max);
3042 parse_sgen_minor (const char *opt)
3045 return SGEN_MINOR_DEFAULT;
3047 if (!strcmp (opt, "simple")) {
3048 return SGEN_MINOR_SIMPLE;
3049 } else if (!strcmp (opt, "simple-par")) {
3050 return SGEN_MINOR_SIMPLE_PARALLEL;
3051 } else if (!strcmp (opt, "split")) {
3052 return SGEN_MINOR_SPLIT;
3054 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default instead.", "Unknown minor collector `%s'.", opt);
3055 return SGEN_MINOR_DEFAULT;
3060 parse_sgen_major (const char *opt)
3063 return SGEN_MAJOR_DEFAULT;
3065 if (!strcmp (opt, "marksweep")) {
3066 return SGEN_MAJOR_SERIAL;
3067 } else if (!strcmp (opt, "marksweep-conc")) {
3068 return SGEN_MAJOR_CONCURRENT;
3069 } else if (!strcmp (opt, "marksweep-conc-par")) {
3070 return SGEN_MAJOR_CONCURRENT_PARALLEL;
3072 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default instead.", "Unknown major collector `%s'.", opt);
3073 return SGEN_MAJOR_DEFAULT;
3079 parse_sgen_mode (const char *opt)
3082 return SGEN_MODE_NONE;
3084 if (!strcmp (opt, "balanced")) {
3085 return SGEN_MODE_BALANCED;
3086 } else if (!strcmp (opt, "throughput")) {
3087 return SGEN_MODE_THROUGHPUT;
3088 } else if (!strcmp (opt, "pause") || g_str_has_prefix (opt, "pause:")) {
3089 return SGEN_MODE_PAUSE;
3091 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default configurations.", "Unknown mode `%s'.", opt);
3092 return SGEN_MODE_NONE;
3097 init_sgen_minor (SgenMinor minor)
3100 case SGEN_MINOR_DEFAULT:
3101 case SGEN_MINOR_SIMPLE:
3102 sgen_simple_nursery_init (&sgen_minor_collector, FALSE);
3104 case SGEN_MINOR_SIMPLE_PARALLEL:
3105 sgen_simple_nursery_init (&sgen_minor_collector, TRUE);
3107 case SGEN_MINOR_SPLIT:
3108 sgen_split_nursery_init (&sgen_minor_collector);
3111 g_assert_not_reached ();
3116 init_sgen_major (SgenMajor major)
3118 if (major == SGEN_MAJOR_DEFAULT)
3119 major = DEFAULT_MAJOR;
3122 case SGEN_MAJOR_SERIAL:
3123 sgen_marksweep_init (&major_collector);
3125 case SGEN_MAJOR_CONCURRENT:
3126 sgen_marksweep_conc_init (&major_collector);
3128 case SGEN_MAJOR_CONCURRENT_PARALLEL:
3129 sgen_marksweep_conc_par_init (&major_collector);
3132 g_assert_not_reached ();
3137 * If sgen mode is set, major/minor configuration is fixed. The other gc_params
3138 * are parsed and processed after major/minor initialization, so it can potentially
3139 * override some knobs set by the sgen mode. We can consider locking out additional
3140 * configurations when gc_modes are used.
3143 init_sgen_mode (SgenMode mode)
3145 SgenMinor minor = SGEN_MINOR_DEFAULT;
3146 SgenMajor major = SGEN_MAJOR_DEFAULT;
3149 case SGEN_MODE_BALANCED:
3151 * Use a dynamic parallel nursery with a major concurrent collector.
3152 * This uses the default values for max pause time and nursery size.
3154 minor = SGEN_MINOR_SIMPLE;
3155 major = SGEN_MAJOR_CONCURRENT;
3156 dynamic_nursery = TRUE;
3158 case SGEN_MODE_THROUGHPUT:
3160 * Use concurrent major to let the mutator do more work. Use a larger
3161 * nursery, without pause time constraints, in order to collect more
3162 * objects in parallel and avoid repetitive collection tasks (pinning,
3163 * root scanning etc)
3165 minor = SGEN_MINOR_SIMPLE_PARALLEL;
3166 major = SGEN_MAJOR_CONCURRENT;
3167 dynamic_nursery = TRUE;
3168 sgen_max_pause_time = 0;
3170 case SGEN_MODE_PAUSE:
3172 * Use concurrent major and dynamic nursery with a more
3173 * aggressive shrinking relative to pause times.
3174 * FIXME use parallel minors
3176 minor = SGEN_MINOR_SIMPLE;
3177 major = SGEN_MAJOR_CONCURRENT;
3178 dynamic_nursery = TRUE;
3179 sgen_max_pause_margin = SGEN_PAUSE_MODE_MAX_PAUSE_MARGIN;
3182 g_assert_not_reached ();
3185 init_sgen_minor (minor);
3186 init_sgen_major (major);
3194 SgenMajor sgen_major = SGEN_MAJOR_DEFAULT;
3195 SgenMinor sgen_minor = SGEN_MINOR_DEFAULT;
3196 SgenMode sgen_mode = SGEN_MODE_NONE;
3197 char *params_opts = NULL;
3198 char *debug_opts = NULL;
3199 size_t max_heap = 0;
3200 size_t soft_limit = 0;
3202 gboolean debug_print_allowance = FALSE;
3203 double allowance_ratio = 0, save_target = 0;
3204 gboolean cement_enabled = TRUE;
3207 result = InterlockedCompareExchange (&gc_initialized, -1, 0);
3210 /* already inited */
3213 /* being inited by another thread */
3214 mono_thread_info_usleep (1000);
3217 /* we will init it */
3220 g_assert_not_reached ();
3222 } while (result != 0);
3224 SGEN_TV_GETTIME (sgen_init_timestamp);
3226 #ifdef SGEN_WITHOUT_MONO
3227 mono_thread_smr_init ();
3230 mono_coop_mutex_init (&gc_mutex);
3232 gc_debug_file = stderr;
3234 mono_coop_mutex_init (&sgen_interruption_mutex);
3236 if ((env = g_getenv (MONO_GC_PARAMS_NAME)) || gc_params_options) {
3237 params_opts = g_strdup_printf ("%s,%s", gc_params_options ? gc_params_options : "", env ? env : "");
3242 opts = g_strsplit (params_opts, ",", -1);
3243 for (ptr = opts; *ptr; ++ptr) {
3245 if (g_str_has_prefix (opt, "major=")) {
3246 opt = strchr (opt, '=') + 1;
3247 sgen_major = parse_sgen_major (opt);
3248 } else if (g_str_has_prefix (opt, "minor=")) {
3249 opt = strchr (opt, '=') + 1;
3250 sgen_minor = parse_sgen_minor (opt);
3251 } else if (g_str_has_prefix (opt, "mode=")) {
3252 opt = strchr (opt, '=') + 1;
3253 sgen_mode = parse_sgen_mode (opt);
3261 sgen_init_internal_allocator ();
3262 sgen_init_nursery_allocator ();
3263 sgen_init_fin_weak_hash ();
3264 sgen_init_hash_table ();
3265 sgen_init_descriptors ();
3266 sgen_init_gray_queues ();
3267 sgen_init_allocator ();
3268 sgen_init_gchandles ();
3270 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_SECTION, SGEN_SIZEOF_GC_MEM_SECTION);
3271 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_GRAY_QUEUE, sizeof (GrayQueueSection));
3273 sgen_client_init ();
3275 if (sgen_mode != SGEN_MODE_NONE) {
3276 if (sgen_minor != SGEN_MINOR_DEFAULT || sgen_major != SGEN_MAJOR_DEFAULT)
3277 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring major/minor configuration", "Major/minor configurations cannot be used with sgen modes");
3278 init_sgen_mode (sgen_mode);
3280 init_sgen_minor (sgen_minor);
3281 init_sgen_major (sgen_major);
3285 gboolean usage_printed = FALSE;
3287 for (ptr = opts; *ptr; ++ptr) {
3289 if (!strcmp (opt, ""))
3291 if (g_str_has_prefix (opt, "major="))
3293 if (g_str_has_prefix (opt, "minor="))
3295 if (g_str_has_prefix (opt, "mode=")) {
3296 if (g_str_has_prefix (opt, "mode=pause:")) {
3297 char *str_pause = strchr (opt, ':') + 1;
3298 int pause = atoi (str_pause);
3300 sgen_max_pause_time = pause;
3302 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default", "Invalid maximum pause time for `pause` sgen mode");
3306 if (g_str_has_prefix (opt, "max-heap-size=")) {
3307 size_t page_size = mono_pagesize ();
3308 size_t max_heap_candidate = 0;
3309 opt = strchr (opt, '=') + 1;
3310 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &max_heap_candidate)) {
3311 max_heap = (max_heap_candidate + page_size - 1) & ~(size_t)(page_size - 1);
3312 if (max_heap != max_heap_candidate)
3313 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Rounding up.", "`max-heap-size` size must be a multiple of %d.", page_size);
3315 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`max-heap-size` must be an integer.");
3319 if (g_str_has_prefix (opt, "soft-heap-limit=")) {
3320 opt = strchr (opt, '=') + 1;
3321 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &soft_limit)) {
3322 if (soft_limit <= 0) {
3323 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be positive.");
3327 sgen_env_var_error (MONO_GC_PARAMS_NAME, NULL, "`soft-heap-limit` must be an integer.");
3331 if (g_str_has_prefix (opt, "nursery-size=")) {
3333 opt = strchr (opt, '=') + 1;
3334 if (*opt && mono_gc_parse_environment_string_extract_number (opt, &val)) {
3335 if ((val & (val - 1))) {
3336 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be a power of two.");
3340 if (val < SGEN_MAX_NURSERY_WASTE) {
3341 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3342 "`nursery-size` must be at least %d bytes.", SGEN_MAX_NURSERY_WASTE);
3346 min_nursery_size = max_nursery_size = val;
3347 dynamic_nursery = FALSE;
3349 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.", "`nursery-size` must be an integer.");
3354 if (g_str_has_prefix (opt, "save-target-ratio=")) {
3356 opt = strchr (opt, '=') + 1;
3357 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "save-target-ratio", opt,
3358 SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO, &val)) {
3363 if (g_str_has_prefix (opt, "default-allowance-ratio=")) {
3365 opt = strchr (opt, '=') + 1;
3366 if (parse_double_in_interval (MONO_GC_PARAMS_NAME, "default-allowance-ratio", opt,
3367 SGEN_MIN_ALLOWANCE_NURSERY_SIZE_RATIO, SGEN_MAX_ALLOWANCE_NURSERY_SIZE_RATIO, &val)) {
3368 allowance_ratio = val;
3373 if (!strcmp (opt, "cementing")) {
3374 cement_enabled = TRUE;
3377 if (!strcmp (opt, "no-cementing")) {
3378 cement_enabled = FALSE;
3382 if (!strcmp (opt, "precleaning")) {
3383 precleaning_enabled = TRUE;
3386 if (!strcmp (opt, "no-precleaning")) {
3387 precleaning_enabled = FALSE;
3391 if (!strcmp (opt, "dynamic-nursery")) {
3392 if (sgen_minor_collector.is_split)
3393 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Using default value.",
3394 "dynamic-nursery not supported with split-nursery.");
3396 dynamic_nursery = TRUE;
3399 if (!strcmp (opt, "no-dynamic-nursery")) {
3400 dynamic_nursery = FALSE;
3404 if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
3407 if (sgen_minor_collector.handle_gc_param && sgen_minor_collector.handle_gc_param (opt))
3410 if (sgen_client_handle_gc_param (opt))
3413 sgen_env_var_error (MONO_GC_PARAMS_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3418 fprintf (stderr, "\n%s must be a comma-delimited list of one or more of the following:\n", MONO_GC_PARAMS_NAME);
3419 fprintf (stderr, " max-heap-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3420 fprintf (stderr, " soft-heap-limit=n (where N is an integer, possibly with a k, m or a g suffix)\n");
3421 fprintf (stderr, " mode=MODE (where MODE is 'balanced', 'throughput' or 'pause[:N]' and N is maximum pause in milliseconds)\n");
3422 fprintf (stderr, " nursery-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3423 fprintf (stderr, " major=COLLECTOR (where COLLECTOR is `marksweep', `marksweep-conc', `marksweep-par')\n");
3424 fprintf (stderr, " minor=COLLECTOR (where COLLECTOR is `simple' or `split')\n");
3425 fprintf (stderr, " wbarrier=WBARRIER (where WBARRIER is `remset' or `cardtable')\n");
3426 fprintf (stderr, " [no-]cementing\n");
3427 fprintf (stderr, " [no-]dynamic-nursery\n");
3428 if (major_collector.print_gc_param_usage)
3429 major_collector.print_gc_param_usage ();
3430 if (sgen_minor_collector.print_gc_param_usage)
3431 sgen_minor_collector.print_gc_param_usage ();
3432 sgen_client_print_gc_params_usage ();
3433 fprintf (stderr, " Experimental options:\n");
3434 fprintf (stderr, " save-target-ratio=R (where R must be between %.2f - %.2f).\n", SGEN_MIN_SAVE_TARGET_RATIO, SGEN_MAX_SAVE_TARGET_RATIO);
3435 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);
3436 fprintf (stderr, "\n");
3438 usage_printed = TRUE;
3444 g_free (params_opts);
3446 alloc_nursery (dynamic_nursery, min_nursery_size, max_nursery_size);
3448 sgen_pinning_init ();
3449 sgen_cement_init (cement_enabled);
3451 if ((env = g_getenv (MONO_GC_DEBUG_NAME)) || gc_debug_options) {
3452 debug_opts = g_strdup_printf ("%s,%s", gc_debug_options ? gc_debug_options : "", env ? env : "");
3457 gboolean usage_printed = FALSE;
3459 opts = g_strsplit (debug_opts, ",", -1);
3460 for (ptr = opts; ptr && *ptr; ptr ++) {
3462 if (!strcmp (opt, ""))
3464 if (opt [0] >= '0' && opt [0] <= '9') {
3465 gc_debug_level = atoi (opt);
3470 char *rf = g_strdup_printf ("%s.%d", opt, mono_process_current_pid ());
3471 gc_debug_file = fopen (rf, "wb");
3473 gc_debug_file = stderr;
3476 } else if (!strcmp (opt, "print-allowance")) {
3477 debug_print_allowance = TRUE;
3478 } else if (!strcmp (opt, "print-pinning")) {
3479 sgen_pin_stats_enable ();
3480 } else if (!strcmp (opt, "verify-before-allocs")) {
3481 verify_before_allocs = 1;
3482 has_per_allocation_action = TRUE;
3483 } else if (g_str_has_prefix (opt, "max-valloc-size=")) {
3484 size_t max_valloc_size;
3485 char *arg = strchr (opt, '=') + 1;
3486 if (*opt && mono_gc_parse_environment_string_extract_number (arg, &max_valloc_size)) {
3487 mono_valloc_set_limit (max_valloc_size);
3489 sgen_env_var_error (MONO_GC_DEBUG_NAME, NULL, "`max-valloc-size` must be an integer.");
3492 } else if (g_str_has_prefix (opt, "verify-before-allocs=")) {
3493 char *arg = strchr (opt, '=') + 1;
3494 verify_before_allocs = atoi (arg);
3495 has_per_allocation_action = TRUE;
3496 } else if (!strcmp (opt, "collect-before-allocs")) {
3497 collect_before_allocs = 1;
3498 has_per_allocation_action = TRUE;
3499 } else if (g_str_has_prefix (opt, "collect-before-allocs=")) {
3500 char *arg = strchr (opt, '=') + 1;
3501 has_per_allocation_action = TRUE;
3502 collect_before_allocs = atoi (arg);
3503 } else if (!strcmp (opt, "verify-before-collections")) {
3504 whole_heap_check_before_collection = TRUE;
3505 } else if (!strcmp (opt, "check-remset-consistency")) {
3506 remset_consistency_checks = TRUE;
3507 nursery_clear_policy = CLEAR_AT_GC;
3508 } else if (!strcmp (opt, "mod-union-consistency-check")) {
3509 if (!major_collector.is_concurrent) {
3510 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`mod-union-consistency-check` only works with concurrent major collector.");
3513 mod_union_consistency_check = TRUE;
3514 } else if (!strcmp (opt, "check-mark-bits")) {
3515 check_mark_bits_after_major_collection = TRUE;
3516 } else if (!strcmp (opt, "check-nursery-pinned")) {
3517 check_nursery_objects_pinned = TRUE;
3518 } else if (!strcmp (opt, "clear-at-gc")) {
3519 nursery_clear_policy = CLEAR_AT_GC;
3520 } else if (!strcmp (opt, "clear-nursery-at-gc")) {
3521 nursery_clear_policy = CLEAR_AT_GC;
3522 } else if (!strcmp (opt, "clear-at-tlab-creation")) {
3523 nursery_clear_policy = CLEAR_AT_TLAB_CREATION;
3524 } else if (!strcmp (opt, "debug-clear-at-tlab-creation")) {
3525 nursery_clear_policy = CLEAR_AT_TLAB_CREATION_DEBUG;
3526 } else if (!strcmp (opt, "check-scan-starts")) {
3527 do_scan_starts_check = TRUE;
3528 } else if (!strcmp (opt, "verify-nursery-at-minor-gc")) {
3529 do_verify_nursery = TRUE;
3530 } else if (!strcmp (opt, "check-concurrent")) {
3531 if (!major_collector.is_concurrent) {
3532 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "`check-concurrent` only works with concurrent major collectors.");
3535 nursery_clear_policy = CLEAR_AT_GC;
3536 do_concurrent_checks = TRUE;
3537 } else if (!strcmp (opt, "dump-nursery-at-minor-gc")) {
3538 do_dump_nursery_content = TRUE;
3539 } else if (!strcmp (opt, "disable-minor")) {
3540 disable_minor_collections = TRUE;
3541 } else if (!strcmp (opt, "disable-major")) {
3542 disable_major_collections = TRUE;
3543 } else if (g_str_has_prefix (opt, "heap-dump=")) {
3544 char *filename = strchr (opt, '=') + 1;
3545 nursery_clear_policy = CLEAR_AT_GC;
3546 sgen_debug_enable_heap_dump (filename);
3547 } else if (g_str_has_prefix (opt, "binary-protocol=")) {
3548 char *filename = strchr (opt, '=') + 1;
3549 char *colon = strrchr (filename, ':');
3552 if (!mono_gc_parse_environment_string_extract_number (colon + 1, &limit)) {
3553 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring limit.", "Binary protocol file size limit must be an integer.");
3558 binary_protocol_init (filename, (long long)limit);
3559 } else if (!strcmp (opt, "nursery-canaries")) {
3560 do_verify_nursery = TRUE;
3561 enable_nursery_canaries = TRUE;
3562 } else if (!sgen_client_handle_gc_debug (opt)) {
3563 sgen_env_var_error (MONO_GC_DEBUG_NAME, "Ignoring.", "Unknown option `%s`.", opt);
3568 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);
3569 fprintf (stderr, "Valid <option>s are:\n");
3570 fprintf (stderr, " collect-before-allocs[=<n>]\n");
3571 fprintf (stderr, " verify-before-allocs[=<n>]\n");
3572 fprintf (stderr, " max-valloc-size=N (where N is an integer, possibly with a k, m or a g suffix)\n");
3573 fprintf (stderr, " check-remset-consistency\n");
3574 fprintf (stderr, " check-mark-bits\n");
3575 fprintf (stderr, " check-nursery-pinned\n");
3576 fprintf (stderr, " verify-before-collections\n");
3577 fprintf (stderr, " verify-nursery-at-minor-gc\n");
3578 fprintf (stderr, " dump-nursery-at-minor-gc\n");
3579 fprintf (stderr, " disable-minor\n");
3580 fprintf (stderr, " disable-major\n");
3581 fprintf (stderr, " check-concurrent\n");
3582 fprintf (stderr, " clear-[nursery-]at-gc\n");
3583 fprintf (stderr, " clear-at-tlab-creation\n");
3584 fprintf (stderr, " debug-clear-at-tlab-creation\n");
3585 fprintf (stderr, " check-scan-starts\n");
3586 fprintf (stderr, " print-allowance\n");
3587 fprintf (stderr, " print-pinning\n");
3588 fprintf (stderr, " heap-dump=<filename>\n");
3589 fprintf (stderr, " binary-protocol=<filename>[:<file-size-limit>]\n");
3590 fprintf (stderr, " nursery-canaries\n");
3591 sgen_client_print_gc_debug_usage ();
3592 fprintf (stderr, "\n");
3594 usage_printed = TRUE;
3601 g_free (debug_opts);
3603 if (check_mark_bits_after_major_collection)
3604 nursery_clear_policy = CLEAR_AT_GC;
3606 if (major_collector.post_param_init)
3607 major_collector.post_param_init (&major_collector);
3609 sgen_thread_pool_start ();
3611 sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
3613 memset (&remset, 0, sizeof (remset));
3615 sgen_card_table_init (&remset);
3617 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");
3621 sgen_init_bridge ();
3625 sgen_gc_initialized ()
3627 return gc_initialized > 0;
3631 sgen_get_nursery_clear_policy (void)
3633 return nursery_clear_policy;
3639 mono_coop_mutex_lock (&gc_mutex);
3643 sgen_gc_unlock (void)
3645 mono_coop_mutex_unlock (&gc_mutex);
3649 sgen_major_collector_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
3651 major_collector.iterate_live_block_ranges (callback);
3655 sgen_major_collector_iterate_block_ranges (sgen_cardtable_block_callback callback)
3657 major_collector.iterate_block_ranges (callback);
3661 sgen_get_major_collector (void)
3663 return &major_collector;
3667 sgen_get_minor_collector (void)
3669 return &sgen_minor_collector;
3673 sgen_get_remset (void)
3679 count_cards (long long *major_total, long long *major_marked, long long *los_total, long long *los_marked)
3681 sgen_get_major_collector ()->count_cards (major_total, major_marked);
3682 sgen_los_count_cards (los_total, los_marked);
3685 static gboolean world_is_stopped = FALSE;
3687 /* LOCKING: assumes the GC lock is held */
3689 sgen_stop_world (int generation)
3691 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3693 SGEN_ASSERT (0, !world_is_stopped, "Why are we stopping a stopped world?");
3695 binary_protocol_world_stopping (generation, sgen_timestamp (), (gpointer) (gsize) mono_native_thread_id_get ());
3697 sgen_client_stop_world (generation);
3699 world_is_stopped = TRUE;
3701 if (binary_protocol_is_heavy_enabled ())
3702 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3703 binary_protocol_world_stopped (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3706 /* LOCKING: assumes the GC lock is held */
3708 sgen_restart_world (int generation)
3710 long long major_total = -1, major_marked = -1, los_total = -1, los_marked = -1;
3713 SGEN_ASSERT (0, world_is_stopped, "Why are we restarting a running world?");
3715 if (binary_protocol_is_heavy_enabled ())
3716 count_cards (&major_total, &major_marked, &los_total, &los_marked);
3717 binary_protocol_world_restarting (generation, sgen_timestamp (), major_total, major_marked, los_total, los_marked);
3719 world_is_stopped = FALSE;
3721 sgen_client_restart_world (generation, &stw_time);
3723 binary_protocol_world_restarted (generation, sgen_timestamp ());
3725 if (sgen_client_bridge_need_processing ())
3726 sgen_client_bridge_processing_finish (generation);
3728 sgen_memgov_collection_end (generation, stw_time);
3732 sgen_is_world_stopped (void)
3734 return world_is_stopped;
3738 sgen_check_whole_heap_stw (void)
3740 sgen_stop_world (0);
3741 sgen_clear_nursery_fragments ();
3742 sgen_check_whole_heap (TRUE);
3743 sgen_restart_world (0);
3747 sgen_timestamp (void)
3749 SGEN_TV_DECLARE (timestamp);
3750 SGEN_TV_GETTIME (timestamp);
3751 return SGEN_TV_ELAPSED (sgen_init_timestamp, timestamp);
3754 #endif /* HAVE_SGEN_GC */