2 * sgen-marksweep.c: The Mark & Sweep major collector.
5 * Mark Probst <mark.probst@gmail.com>
7 * Copyright 2009-2010 Novell, Inc.
8 * Copyright (C) 2012 Xamarin Inc
10 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
22 #include "mono/sgen/sgen-gc.h"
23 #include "mono/sgen/sgen-protocol.h"
24 #include "mono/sgen/sgen-cardtable.h"
25 #include "mono/sgen/sgen-memory-governor.h"
26 #include "mono/sgen/sgen-layout-stats.h"
27 #include "mono/sgen/sgen-pointer-queue.h"
28 #include "mono/sgen/sgen-array-list.h"
29 #include "mono/sgen/sgen-pinning.h"
30 #include "mono/sgen/sgen-workers.h"
31 #include "mono/sgen/sgen-thread-pool.h"
32 #include "mono/sgen/sgen-client.h"
33 #include "mono/utils/mono-memory-model.h"
35 #if defined(ARCH_MIN_MS_BLOCK_SIZE) && defined(ARCH_MIN_MS_BLOCK_SIZE_SHIFT)
36 #define MS_BLOCK_SIZE ARCH_MIN_MS_BLOCK_SIZE
37 #define MS_BLOCK_SIZE_SHIFT ARCH_MIN_MS_BLOCK_SIZE_SHIFT
39 #define MS_BLOCK_SIZE_SHIFT 14 /* INT FASTENABLE */
40 #define MS_BLOCK_SIZE (1 << MS_BLOCK_SIZE_SHIFT)
42 #define MAJOR_SECTION_SIZE MS_BLOCK_SIZE
43 #define CARDS_PER_BLOCK (MS_BLOCK_SIZE / CARD_SIZE_IN_BYTES)
46 * Don't allocate single blocks, but alloc a contingent of this many
47 * blocks in one swoop. This must be a power of two.
49 #define MS_BLOCK_ALLOC_NUM 32
52 * Number of bytes before the first object in a block. At the start
53 * of a block is the MSBlockHeader, then opional padding, then come
54 * the objects, so this must be >= sizeof (MSBlockHeader).
56 #define MS_BLOCK_SKIP ((sizeof (MSBlockHeader) + 15) & ~15)
58 #define MS_BLOCK_FREE (MS_BLOCK_SIZE - MS_BLOCK_SKIP)
60 #define MS_NUM_MARK_WORDS ((MS_BLOCK_SIZE / SGEN_ALLOC_ALIGN + sizeof (mword) * 8 - 1) / (sizeof (mword) * 8))
63 * Blocks progress from one state to the next:
65 * SWEPT The block is fully swept. It might or might not be in
68 * MARKING The block might or might not contain live objects. If
69 * we're in between an initial collection pause and the
70 * finishing pause, the block might or might not be in a
73 * CHECKING The sweep thread is investigating the block to determine
74 * whether or not it contains live objects. The block is
77 * NEED_SWEEPING The block contains live objects but has not yet been
78 * swept. It also contains free slots. It is in a block
81 * SWEEPING The block is being swept. It might be in a free list.
88 BLOCK_STATE_NEED_SWEEPING,
92 typedef struct _MSBlockInfo MSBlockInfo;
96 * FIXME: Do we even need this? It's only used during sweep and might be worth
97 * recalculating to save the space.
99 guint16 obj_size_index;
100 /* FIXME: Reduce this - it only needs a byte. */
101 volatile gint32 state;
102 unsigned int pinned : 1;
103 unsigned int has_references : 1;
104 unsigned int has_pinned : 1; /* means cannot evacuate */
105 unsigned int is_to_space : 1;
106 void ** volatile free_list;
107 MSBlockInfo * volatile next_free;
108 guint8 * volatile cardtable_mod_union;
109 mword mark_words [MS_NUM_MARK_WORDS];
112 #define MS_BLOCK_FOR_BLOCK_INFO(b) ((char*)(b))
114 #define MS_BLOCK_OBJ(b,i) ((GCObject *)(MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP + (b)->obj_size * (i)))
115 #define MS_BLOCK_OBJ_FOR_SIZE(b,i,obj_size) (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP + (obj_size) * (i))
116 #define MS_BLOCK_DATA_FOR_OBJ(o) ((char*)((mword)(o) & ~(mword)(MS_BLOCK_SIZE - 1)))
122 #define MS_BLOCK_FOR_OBJ(o) (&((MSBlockHeader*)MS_BLOCK_DATA_FOR_OBJ ((o)))->info)
124 /* object index will always be small */
125 #define MS_BLOCK_OBJ_INDEX(o,b) ((int)(((char*)(o) - (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP)) / (b)->obj_size))
127 //casting to int is fine since blocks are 32k
128 #define MS_CALC_MARK_BIT(w,b,o) do { \
129 int i = ((int)((char*)(o) - MS_BLOCK_DATA_FOR_OBJ ((o)))) >> SGEN_ALLOC_ALIGN_BITS; \
130 if (sizeof (mword) == 4) { \
139 #define MS_MARK_BIT(bl,w,b) ((bl)->mark_words [(w)] & (ONE_P << (b)))
140 #define MS_SET_MARK_BIT(bl,w,b) ((bl)->mark_words [(w)] |= (ONE_P << (b)))
142 #define MS_OBJ_ALLOCED(o,b) (*(void**)(o) && (*(char**)(o) < MS_BLOCK_FOR_BLOCK_INFO (b) || *(char**)(o) >= MS_BLOCK_FOR_BLOCK_INFO (b) + MS_BLOCK_SIZE))
144 #define MS_BLOCK_OBJ_SIZE_FACTOR (pow (2.0, 1.0 / 3))
147 * This way we can lookup block object size indexes for sizes up to
148 * 256 bytes with a single load.
150 #define MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES 32
152 static int *block_obj_sizes;
153 static int num_block_obj_sizes;
154 static int fast_block_obj_size_indexes [MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES];
156 #define MS_BLOCK_FLAG_PINNED 1
157 #define MS_BLOCK_FLAG_REFS 2
159 #define MS_BLOCK_TYPE_MAX 4
161 static gboolean *evacuate_block_obj_sizes;
162 static float evacuation_threshold = 0.666f;
164 static gboolean lazy_sweep = FALSE;
168 SWEEP_STATE_NEED_SWEEPING,
169 SWEEP_STATE_SWEEPING,
170 SWEEP_STATE_SWEEPING_AND_ITERATING,
171 SWEEP_STATE_COMPACTING
174 static volatile int sweep_state = SWEEP_STATE_SWEPT;
176 static gboolean concurrent_mark;
177 static gboolean concurrent_sweep = TRUE;
179 #define BLOCK_IS_TAGGED_HAS_REFERENCES(bl) SGEN_POINTER_IS_TAGGED_1 ((bl))
180 #define BLOCK_TAG_HAS_REFERENCES(bl) SGEN_POINTER_TAG_1 ((bl))
182 #define BLOCK_IS_TAGGED_CHECKING(bl) SGEN_POINTER_IS_TAGGED_2 ((bl))
183 #define BLOCK_TAG_CHECKING(bl) SGEN_POINTER_TAG_2 ((bl))
185 #define BLOCK_UNTAG(bl) ((MSBlockInfo *)SGEN_POINTER_UNTAG_12 ((bl)))
187 #define BLOCK_TAG(bl) ((bl)->has_references ? BLOCK_TAG_HAS_REFERENCES ((bl)) : (bl))
189 /* all allocated blocks in the system */
190 static SgenArrayList allocated_blocks = SGEN_ARRAY_LIST_INIT (NULL, NULL, NULL, INTERNAL_MEM_PIN_QUEUE);
192 /* non-allocated block free-list */
193 static void *empty_blocks = NULL;
194 static size_t num_empty_blocks = 0;
196 #define FOREACH_BLOCK_NO_LOCK(bl) { \
197 volatile gpointer *slot; \
198 SGEN_ASSERT (0, !sweep_in_progress (), "Can't iterate blocks while sweep is in progress."); \
199 SGEN_ARRAY_LIST_FOREACH_SLOT (&allocated_blocks, slot) { \
200 (bl) = BLOCK_UNTAG (*slot);
201 #define FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK(bl,hr) { \
202 volatile gpointer *slot; \
203 SGEN_ASSERT (0, !sweep_in_progress (), "Can't iterate blocks while sweep is in progress."); \
204 SGEN_ARRAY_LIST_FOREACH_SLOT (&allocated_blocks, slot) { \
205 (bl) = (MSBlockInfo *) (*slot); \
206 (hr) = BLOCK_IS_TAGGED_HAS_REFERENCES ((bl)); \
207 (bl) = BLOCK_UNTAG ((bl));
208 #define END_FOREACH_BLOCK_NO_LOCK } SGEN_ARRAY_LIST_END_FOREACH_SLOT; }
210 static volatile size_t num_major_sections = 0;
212 * One free block list for each block object size. We add and remove blocks from these
213 * lists lock-free via CAS.
215 * Blocks accessed/removed from `free_block_lists`:
216 * from the mutator (with GC lock held)
217 * in nursery collections
218 * in non-concurrent major collections
219 * in the finishing pause of concurrent major collections (whole list is cleared)
221 * Blocks added to `free_block_lists`:
222 * in the sweeping thread
223 * during nursery collections
224 * from domain clearing (with the world stopped and no sweeping happening)
226 * The only item of those that doesn't require the GC lock is the sweep thread. The sweep
227 * thread only ever adds blocks to the free list, so the ABA problem can't occur.
229 static MSBlockInfo * volatile *free_block_lists [MS_BLOCK_TYPE_MAX];
231 static guint64 stat_major_blocks_alloced = 0;
232 static guint64 stat_major_blocks_freed = 0;
233 static guint64 stat_major_blocks_lazy_swept = 0;
235 #if SIZEOF_VOID_P != 8
236 static guint64 stat_major_blocks_freed_ideal = 0;
237 static guint64 stat_major_blocks_freed_less_ideal = 0;
238 static guint64 stat_major_blocks_freed_individual = 0;
239 static guint64 stat_major_blocks_alloced_less_ideal = 0;
242 #ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
243 static guint64 num_major_objects_marked = 0;
244 #define INC_NUM_MAJOR_OBJECTS_MARKED() (++num_major_objects_marked)
246 #define INC_NUM_MAJOR_OBJECTS_MARKED()
249 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
250 static mono_mutex_t scanned_objects_list_lock;
251 static SgenPointerQueue scanned_objects_list;
254 add_scanned_object (void *ptr)
256 if (!binary_protocol_is_enabled ())
259 mono_os_mutex_lock (&scanned_objects_list_lock);
260 sgen_pointer_queue_add (&scanned_objects_list, ptr);
261 mono_os_mutex_unlock (&scanned_objects_list_lock);
265 static gboolean sweep_block (MSBlockInfo *block);
268 ms_find_block_obj_size_index (size_t size)
271 SGEN_ASSERT (9, size <= SGEN_MAX_SMALL_OBJ_SIZE, "size %zd is bigger than max small object size %d", size, SGEN_MAX_SMALL_OBJ_SIZE);
272 for (i = 0; i < num_block_obj_sizes; ++i)
273 if (block_obj_sizes [i] >= size)
275 g_error ("no object of size %zd\n", size);
279 #define FREE_BLOCKS_FROM(lists,p,r) (lists [((p) ? MS_BLOCK_FLAG_PINNED : 0) | ((r) ? MS_BLOCK_FLAG_REFS : 0)])
280 #define FREE_BLOCKS(p,r) (FREE_BLOCKS_FROM (free_block_lists, (p), (r)))
282 #define MS_BLOCK_OBJ_SIZE_INDEX(s) \
283 (((s)+7)>>3 < MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES ? \
284 fast_block_obj_size_indexes [((s)+7)>>3] : \
285 ms_find_block_obj_size_index ((s)))
288 major_alloc_heap (mword nursery_size, mword nursery_align, int the_nursery_bits)
292 start = (char *)sgen_alloc_os_memory_aligned (nursery_size, nursery_align, (SgenAllocFlags)(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE), "nursery");
294 start = (char *)sgen_alloc_os_memory (nursery_size, (SgenAllocFlags)(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE), "nursery");
300 update_heap_boundaries_for_block (MSBlockInfo *block)
302 sgen_update_heap_boundaries ((mword)MS_BLOCK_FOR_BLOCK_INFO (block), (mword)MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE);
309 ms_get_empty_block (void)
313 void *block, *empty, *next;
318 * We try allocating MS_BLOCK_ALLOC_NUM blocks first. If that's
319 * unsuccessful, we halve the number of blocks and try again, until we're at
320 * 1. If that doesn't work, either, we assert.
322 int alloc_num = MS_BLOCK_ALLOC_NUM;
324 p = (char *)sgen_alloc_os_memory_aligned (MS_BLOCK_SIZE * alloc_num, MS_BLOCK_SIZE,
325 (SgenAllocFlags)(SGEN_ALLOC_HEAP | SGEN_ALLOC_ACTIVATE),
326 alloc_num == 1 ? "major heap section" : NULL);
332 for (i = 0; i < alloc_num; ++i) {
335 * We do the free list update one after the
336 * other so that other threads can use the new
337 * blocks as quickly as possible.
340 empty = empty_blocks;
341 *(void**)block = empty;
342 } while (SGEN_CAS_PTR ((gpointer*)&empty_blocks, block, empty) != empty);
346 SGEN_ATOMIC_ADD_P (num_empty_blocks, alloc_num);
348 stat_major_blocks_alloced += alloc_num;
349 #if SIZEOF_VOID_P != 8
350 if (alloc_num != MS_BLOCK_ALLOC_NUM)
351 stat_major_blocks_alloced_less_ideal += alloc_num;
356 empty = empty_blocks;
360 next = *(void**)block;
361 } while (SGEN_CAS_PTR (&empty_blocks, next, empty) != empty);
363 SGEN_ATOMIC_ADD_P (num_empty_blocks, -1);
365 *(void**)block = NULL;
367 g_assert (!((mword)block & (MS_BLOCK_SIZE - 1)));
373 * This doesn't actually free a block immediately, but enqueues it into the `empty_blocks`
374 * list, where it will either be freed later on, or reused in nursery collections.
377 ms_free_block (void *block)
381 sgen_memgov_release_space (MS_BLOCK_SIZE, SPACE_MAJOR);
382 memset (block, 0, MS_BLOCK_SIZE);
385 empty = empty_blocks;
386 *(void**)block = empty;
387 } while (SGEN_CAS_PTR (&empty_blocks, block, empty) != empty);
389 SGEN_ATOMIC_ADD_P (num_empty_blocks, 1);
391 binary_protocol_block_free (block, MS_BLOCK_SIZE);
395 sweep_in_progress (void)
397 int state = sweep_state;
398 return state == SWEEP_STATE_SWEEPING ||
399 state == SWEEP_STATE_SWEEPING_AND_ITERATING ||
400 state == SWEEP_STATE_COMPACTING;
403 static inline gboolean
404 block_is_swept_or_marking (MSBlockInfo *block)
406 gint32 state = block->state;
407 return state == BLOCK_STATE_SWEPT || state == BLOCK_STATE_MARKING;
410 //#define MARKSWEEP_CONSISTENCY_CHECK
412 #ifdef MARKSWEEP_CONSISTENCY_CHECK
414 check_block_free_list (MSBlockInfo *block, int size, gboolean pinned)
416 SGEN_ASSERT (0, !sweep_in_progress (), "Can't examine allocated blocks during sweep");
417 for (; block; block = block->next_free) {
418 SGEN_ASSERT (0, block->state != BLOCK_STATE_CHECKING, "Can't have a block we're checking in a free list.");
419 g_assert (block->obj_size == size);
420 g_assert ((pinned && block->pinned) || (!pinned && !block->pinned));
422 /* blocks in the free lists must have at least
424 g_assert (block->free_list);
426 /* the block must be in the allocated_blocks array */
427 g_assert (sgen_array_list_find (&allocated_blocks, BLOCK_TAG (block)) != (guint32)-1);
432 check_empty_blocks (void)
436 for (p = empty_blocks; p; p = *(void**)p)
438 g_assert (i == num_empty_blocks);
442 consistency_check (void)
447 /* check all blocks */
448 FOREACH_BLOCK_NO_LOCK (block) {
449 int count = MS_BLOCK_FREE / block->obj_size;
453 /* count number of free slots */
454 for (i = 0; i < count; ++i) {
455 void **obj = (void**) MS_BLOCK_OBJ (block, i);
456 if (!MS_OBJ_ALLOCED (obj, block))
460 /* check free list */
461 for (free = block->free_list; free; free = (void**)*free) {
462 g_assert (MS_BLOCK_FOR_OBJ (free) == block);
465 g_assert (num_free == 0);
467 /* check all mark words are zero */
468 if (!sgen_concurrent_collection_in_progress () && block_is_swept_or_marking (block)) {
469 for (i = 0; i < MS_NUM_MARK_WORDS; ++i)
470 g_assert (block->mark_words [i] == 0);
472 } END_FOREACH_BLOCK_NO_LOCK;
474 /* check free blocks */
475 for (i = 0; i < num_block_obj_sizes; ++i) {
477 for (j = 0; j < MS_BLOCK_TYPE_MAX; ++j)
478 check_block_free_list (free_block_lists [j][i], block_obj_sizes [i], j & MS_BLOCK_FLAG_PINNED);
481 check_empty_blocks ();
486 add_free_block (MSBlockInfo * volatile *free_blocks, int size_index, MSBlockInfo *block)
490 block->next_free = old = free_blocks [size_index];
491 } while (SGEN_CAS_PTR ((volatile gpointer *)&free_blocks [size_index], block, old) != old);
494 static void major_finish_sweep_checking (void);
497 ms_alloc_block (int size_index, gboolean pinned, gboolean has_references)
499 int size = block_obj_sizes [size_index];
500 int count = MS_BLOCK_FREE / size;
502 MSBlockInfo * volatile * free_blocks = FREE_BLOCKS (pinned, has_references);
506 if (!sgen_memgov_try_alloc_space (MS_BLOCK_SIZE, SPACE_MAJOR))
509 info = (MSBlockInfo*)ms_get_empty_block ();
511 SGEN_ASSERT (9, count >= 2, "block with %d objects, it must hold at least 2", count);
513 info->obj_size = size;
514 info->obj_size_index = size_index;
515 info->pinned = pinned;
516 info->has_references = has_references;
517 info->has_pinned = pinned;
519 * Blocks that are to-space are not evacuated from. During an major collection
520 * blocks are allocated for two reasons: evacuating objects from the nursery and
521 * evacuating them from major blocks marked for evacuation. In both cases we don't
522 * want further evacuation. We also don't want to evacuate objects allocated during
523 * the concurrent mark since it would add pointless stress on the finishing pause.
525 info->is_to_space = (sgen_get_current_collection_generation () == GENERATION_OLD) || sgen_concurrent_collection_in_progress ();
526 info->state = info->is_to_space ? BLOCK_STATE_MARKING : BLOCK_STATE_SWEPT;
527 SGEN_ASSERT (6, !sweep_in_progress () || info->state == BLOCK_STATE_SWEPT, "How do we add a new block to be swept while sweeping?");
528 info->cardtable_mod_union = NULL;
530 update_heap_boundaries_for_block (info);
532 binary_protocol_block_alloc (info, MS_BLOCK_SIZE);
534 /* build free list */
535 obj_start = MS_BLOCK_FOR_BLOCK_INFO (info) + MS_BLOCK_SKIP;
536 info->free_list = (void**)obj_start;
537 /* we're skipping the last one - it must be nulled */
538 for (i = 0; i < count - 1; ++i) {
539 char *next_obj_start = obj_start + size;
540 *(void**)obj_start = next_obj_start;
541 obj_start = next_obj_start;
544 *(void**)obj_start = NULL;
546 add_free_block (free_blocks, size_index, info);
549 * Adding to the allocated_blocks array is racy with the removal of nulls when
550 * sweeping. We wait for sweep to finish to avoid that.
552 * The memory barrier here and in `sweep_job_func()` are required because we need
553 * `allocated_blocks` synchronized between this and the sweep thread.
555 major_finish_sweep_checking ();
556 mono_memory_barrier ();
558 sgen_array_list_add (&allocated_blocks, BLOCK_TAG (info), 0, FALSE);
560 SGEN_ATOMIC_ADD_P (num_major_sections, 1);
565 ptr_is_from_pinned_alloc (char *ptr)
569 FOREACH_BLOCK_NO_LOCK (block) {
570 if (ptr >= MS_BLOCK_FOR_BLOCK_INFO (block) && ptr <= MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE)
571 return block->pinned;
572 } END_FOREACH_BLOCK_NO_LOCK;
577 ensure_can_access_block_free_list (MSBlockInfo *block)
581 switch (block->state) {
582 case BLOCK_STATE_SWEPT:
583 case BLOCK_STATE_MARKING:
585 case BLOCK_STATE_CHECKING:
586 SGEN_ASSERT (0, FALSE, "How did we get a block that's being checked from a free list?");
588 case BLOCK_STATE_NEED_SWEEPING:
589 if (sweep_block (block))
590 ++stat_major_blocks_lazy_swept;
592 case BLOCK_STATE_SWEEPING:
593 /* FIXME: do this more elegantly */
597 SGEN_ASSERT (0, FALSE, "Illegal block state");
604 unlink_slot_from_free_list_uncontested (MSBlockInfo * volatile *free_blocks, int size_index)
606 MSBlockInfo *block, *next_free_block;
607 void *obj, *next_free_slot;
610 block = free_blocks [size_index];
611 SGEN_ASSERT (9, block, "no free block to unlink from free_blocks %p size_index %d", free_blocks, size_index);
613 ensure_can_access_block_free_list (block);
615 obj = block->free_list;
616 SGEN_ASSERT (6, obj, "block %p in free list had no available object to alloc from", block);
618 next_free_slot = *(void**)obj;
619 if (next_free_slot) {
620 block->free_list = (gpointer *)next_free_slot;
624 next_free_block = block->next_free;
625 if (SGEN_CAS_PTR ((volatile gpointer *)&free_blocks [size_index], next_free_block, block) != block)
628 block->free_list = NULL;
629 block->next_free = NULL;
635 alloc_obj (GCVTable vtable, size_t size, gboolean pinned, gboolean has_references)
637 int size_index = MS_BLOCK_OBJ_SIZE_INDEX (size);
638 MSBlockInfo * volatile * free_blocks = FREE_BLOCKS (pinned, has_references);
641 if (!free_blocks [size_index]) {
642 if (G_UNLIKELY (!ms_alloc_block (size_index, pinned, has_references)))
646 obj = unlink_slot_from_free_list_uncontested (free_blocks, size_index);
648 /* FIXME: assumes object layout */
649 *(GCVTable*)obj = vtable;
651 return (GCObject *)obj;
655 major_alloc_object (GCVTable vtable, size_t size, gboolean has_references)
657 return alloc_obj (vtable, size, FALSE, has_references);
661 * We're not freeing the block if it's empty. We leave that work for
662 * the next major collection.
664 * This is just called from the domain clearing code, which runs in a
665 * single thread and has the GC lock, so we don't need an extra lock.
668 free_object (GCObject *obj, size_t size, gboolean pinned)
670 MSBlockInfo *block = MS_BLOCK_FOR_OBJ (obj);
672 gboolean in_free_list;
674 SGEN_ASSERT (9, sweep_state == SWEEP_STATE_SWEPT, "Should have waited for sweep to free objects.");
676 ensure_can_access_block_free_list (block);
677 SGEN_ASSERT (9, (pinned && block->pinned) || (!pinned && !block->pinned), "free-object pinning mixup object %p pinned %d block %p pinned %d", obj, pinned, block, block->pinned);
678 SGEN_ASSERT (9, MS_OBJ_ALLOCED (obj, block), "object %p is already free", obj);
679 MS_CALC_MARK_BIT (word, bit, obj);
680 SGEN_ASSERT (9, !MS_MARK_BIT (block, word, bit), "object %p has mark bit set", obj);
682 memset (obj, 0, size);
684 in_free_list = !!block->free_list;
685 *(void**)obj = block->free_list;
686 block->free_list = (void**)obj;
689 MSBlockInfo * volatile *free_blocks = FREE_BLOCKS (pinned, block->has_references);
690 int size_index = MS_BLOCK_OBJ_SIZE_INDEX (size);
691 SGEN_ASSERT (9, !block->next_free, "block %p doesn't have a free-list of object but belongs to a free-list of blocks", block);
692 add_free_block (free_blocks, size_index, block);
697 major_free_non_pinned_object (GCObject *obj, size_t size)
699 free_object (obj, size, FALSE);
702 /* size is a multiple of SGEN_ALLOC_ALIGN */
704 major_alloc_small_pinned_obj (GCVTable vtable, size_t size, gboolean has_references)
708 res = alloc_obj (vtable, size, TRUE, has_references);
709 /*If we failed to alloc memory, we better try releasing memory
710 *as pinned alloc is requested by the runtime.
713 sgen_perform_collection (0, GENERATION_OLD, "pinned alloc failure", TRUE);
714 res = alloc_obj (vtable, size, TRUE, has_references);
716 return (GCObject *)res;
720 free_pinned_object (GCObject *obj, size_t size)
722 free_object (obj, size, TRUE);
726 * size is already rounded up and we hold the GC lock.
729 major_alloc_degraded (GCVTable vtable, size_t size)
733 obj = alloc_obj (vtable, size, FALSE, SGEN_VTABLE_HAS_REFERENCES (vtable));
734 if (G_LIKELY (obj)) {
735 HEAVY_STAT (++stat_objects_alloced_degraded);
736 HEAVY_STAT (stat_bytes_alloced_degraded += size);
742 * obj is some object. If it's not in the major heap (i.e. if it's in
743 * the nursery or LOS), return FALSE. Otherwise return whether it's
744 * been marked or copied.
747 major_is_object_live (GCObject *obj)
753 if (sgen_ptr_in_nursery (obj))
756 objsize = SGEN_ALIGN_UP (sgen_safe_object_get_size (obj));
759 if (objsize > SGEN_MAX_SMALL_OBJ_SIZE)
762 /* now we know it's in a major block */
763 block = MS_BLOCK_FOR_OBJ (obj);
764 SGEN_ASSERT (9, !block->pinned, "block %p is pinned, BTW why is this bad?", block);
765 MS_CALC_MARK_BIT (word, bit, obj);
766 return MS_MARK_BIT (block, word, bit) ? TRUE : FALSE;
770 major_ptr_is_in_non_pinned_space (char *ptr, char **start)
774 FOREACH_BLOCK_NO_LOCK (block) {
775 if (ptr >= MS_BLOCK_FOR_BLOCK_INFO (block) && ptr <= MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE) {
776 int count = MS_BLOCK_FREE / block->obj_size;
780 for (i = 0; i <= count; ++i) {
781 if (ptr >= (char*)MS_BLOCK_OBJ (block, i) && ptr < (char*)MS_BLOCK_OBJ (block, i + 1)) {
782 *start = (char *)MS_BLOCK_OBJ (block, i);
786 return !block->pinned;
788 } END_FOREACH_BLOCK_NO_LOCK;
793 try_set_sweep_state (int new_, int expected)
795 int old = SGEN_CAS (&sweep_state, new_, expected);
796 return old == expected;
800 set_sweep_state (int new_, int expected)
802 gboolean success = try_set_sweep_state (new_, expected);
803 SGEN_ASSERT (0, success, "Could not set sweep state.");
806 static gboolean ensure_block_is_checked_for_sweeping (guint32 block_index, gboolean wait, gboolean *have_checked);
808 static SgenThreadPoolJob * volatile sweep_job;
811 major_finish_sweep_checking (void)
814 SgenThreadPoolJob *job;
817 switch (sweep_state) {
818 case SWEEP_STATE_SWEPT:
819 case SWEEP_STATE_NEED_SWEEPING:
821 case SWEEP_STATE_SWEEPING:
822 if (try_set_sweep_state (SWEEP_STATE_SWEEPING_AND_ITERATING, SWEEP_STATE_SWEEPING))
825 case SWEEP_STATE_SWEEPING_AND_ITERATING:
826 SGEN_ASSERT (0, FALSE, "Is there another minor collection running?");
828 case SWEEP_STATE_COMPACTING:
831 SGEN_ASSERT (0, FALSE, "Invalid sweep state.");
836 * We're running with the world stopped and the only other thread doing work is the
837 * sweep thread, which doesn't add blocks to the array, so we can safely access
840 for (block_index = 0; block_index < allocated_blocks.next_slot; ++block_index)
841 ensure_block_is_checked_for_sweeping (block_index, FALSE, NULL);
843 set_sweep_state (SWEEP_STATE_SWEEPING, SWEEP_STATE_SWEEPING_AND_ITERATING);
848 sgen_thread_pool_job_wait (job);
849 SGEN_ASSERT (0, !sweep_job, "Why did the sweep job not null itself?");
850 SGEN_ASSERT (0, sweep_state == SWEEP_STATE_SWEPT, "How is the sweep job done but we're not swept?");
854 major_iterate_objects (IterateObjectsFlags flags, IterateObjectCallbackFunc callback, void *data)
856 gboolean sweep = flags & ITERATE_OBJECTS_SWEEP;
857 gboolean non_pinned = flags & ITERATE_OBJECTS_NON_PINNED;
858 gboolean pinned = flags & ITERATE_OBJECTS_PINNED;
861 major_finish_sweep_checking ();
862 FOREACH_BLOCK_NO_LOCK (block) {
863 int count = MS_BLOCK_FREE / block->obj_size;
866 if (block->pinned && !pinned)
868 if (!block->pinned && !non_pinned)
870 if (sweep && lazy_sweep) {
872 SGEN_ASSERT (6, block->state == BLOCK_STATE_SWEPT, "Block must be swept after sweeping");
875 for (i = 0; i < count; ++i) {
876 void **obj = (void**) MS_BLOCK_OBJ (block, i);
878 * We've finished sweep checking, but if we're sweeping lazily and
879 * the flags don't require us to sweep, the block might still need
880 * sweeping. In that case, we need to consult the mark bits to tell
881 * us whether an object slot is live.
883 if (!block_is_swept_or_marking (block)) {
885 SGEN_ASSERT (6, !sweep && block->state == BLOCK_STATE_NEED_SWEEPING, "Has sweeping not finished?");
886 MS_CALC_MARK_BIT (word, bit, obj);
887 if (!MS_MARK_BIT (block, word, bit))
890 if (MS_OBJ_ALLOCED (obj, block))
891 callback ((GCObject*)obj, block->obj_size, data);
893 } END_FOREACH_BLOCK_NO_LOCK;
897 major_is_valid_object (char *object)
901 FOREACH_BLOCK_NO_LOCK (block) {
905 if ((MS_BLOCK_FOR_BLOCK_INFO (block) > object) || ((MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE) <= object))
908 idx = MS_BLOCK_OBJ_INDEX (object, block);
909 obj = (char*)MS_BLOCK_OBJ (block, idx);
912 return MS_OBJ_ALLOCED (obj, block);
913 } END_FOREACH_BLOCK_NO_LOCK;
920 major_describe_pointer (char *ptr)
924 FOREACH_BLOCK_NO_LOCK (block) {
932 if ((MS_BLOCK_FOR_BLOCK_INFO (block) > ptr) || ((MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE) <= ptr))
935 SGEN_LOG (0, "major-ptr (block %p sz %d pin %d ref %d)\n",
936 MS_BLOCK_FOR_BLOCK_INFO (block), block->obj_size, block->pinned, block->has_references);
938 idx = MS_BLOCK_OBJ_INDEX (ptr, block);
939 obj = (char*)MS_BLOCK_OBJ (block, idx);
940 live = MS_OBJ_ALLOCED (obj, block);
941 vtable = live ? SGEN_LOAD_VTABLE ((GCObject*)obj) : NULL;
943 MS_CALC_MARK_BIT (w, b, obj);
944 marked = MS_MARK_BIT (block, w, b);
949 SGEN_LOG (0, "object");
951 SGEN_LOG (0, "dead-object");
954 SGEN_LOG (0, "interior-ptr offset %zd", ptr - obj);
956 SGEN_LOG (0, "dead-interior-ptr offset %zd", ptr - obj);
959 SGEN_LOG (0, " marked %d)\n", marked ? 1 : 0);
962 } END_FOREACH_BLOCK_NO_LOCK;
968 major_check_scan_starts (void)
973 major_dump_heap (FILE *heap_dump_file)
976 int *slots_available = (int *)alloca (sizeof (int) * num_block_obj_sizes);
977 int *slots_used = (int *)alloca (sizeof (int) * num_block_obj_sizes);
980 for (i = 0; i < num_block_obj_sizes; ++i)
981 slots_available [i] = slots_used [i] = 0;
983 FOREACH_BLOCK_NO_LOCK (block) {
984 int index = ms_find_block_obj_size_index (block->obj_size);
985 int count = MS_BLOCK_FREE / block->obj_size;
987 slots_available [index] += count;
988 for (i = 0; i < count; ++i) {
989 if (MS_OBJ_ALLOCED (MS_BLOCK_OBJ (block, i), block))
990 ++slots_used [index];
992 } END_FOREACH_BLOCK_NO_LOCK;
994 fprintf (heap_dump_file, "<occupancies>\n");
995 for (i = 0; i < num_block_obj_sizes; ++i) {
996 fprintf (heap_dump_file, "<occupancy size=\"%d\" available=\"%d\" used=\"%d\" />\n",
997 block_obj_sizes [i], slots_available [i], slots_used [i]);
999 fprintf (heap_dump_file, "</occupancies>\n");
1001 FOREACH_BLOCK_NO_LOCK (block) {
1002 int count = MS_BLOCK_FREE / block->obj_size;
1006 fprintf (heap_dump_file, "<section type=\"%s\" size=\"%zu\">\n", "old", (size_t)MS_BLOCK_FREE);
1008 for (i = 0; i <= count; ++i) {
1009 if ((i < count) && MS_OBJ_ALLOCED (MS_BLOCK_OBJ (block, i), block)) {
1014 sgen_dump_occupied ((char *)MS_BLOCK_OBJ (block, start), (char *)MS_BLOCK_OBJ (block, i), MS_BLOCK_FOR_BLOCK_INFO (block));
1020 fprintf (heap_dump_file, "</section>\n");
1021 } END_FOREACH_BLOCK_NO_LOCK;
1025 get_cardtable_mod_union_for_block (MSBlockInfo *block, gboolean allocate)
1027 guint8 *mod_union = block->cardtable_mod_union;
1033 mod_union = sgen_card_table_alloc_mod_union (MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE);
1034 other = (guint8 *)SGEN_CAS_PTR ((gpointer*)&block->cardtable_mod_union, mod_union, NULL);
1036 SGEN_ASSERT (0, block->cardtable_mod_union == mod_union, "Why did CAS not replace?");
1039 sgen_card_table_free_mod_union (mod_union, MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE);
1043 static inline guint8*
1044 major_get_cardtable_mod_union_for_reference (char *ptr)
1046 MSBlockInfo *block = MS_BLOCK_FOR_OBJ (ptr);
1047 size_t offset = sgen_card_table_get_card_offset (ptr, (char*)sgen_card_table_align_pointer (MS_BLOCK_FOR_BLOCK_INFO (block)));
1048 guint8 *mod_union = get_cardtable_mod_union_for_block (block, TRUE);
1049 SGEN_ASSERT (0, mod_union, "FIXME: optionally allocate the mod union if it's not here and CAS it in.");
1050 return &mod_union [offset];
1054 * Mark the mod-union card for `ptr`, which must be a reference within the object `obj`.
1057 mark_mod_union_card (GCObject *obj, void **ptr, GCObject *value_obj)
1059 int type = sgen_obj_get_descriptor (obj) & DESC_TYPE_MASK;
1060 if (sgen_safe_object_is_small (obj, type)) {
1061 guint8 *card_byte = major_get_cardtable_mod_union_for_reference ((char*)ptr);
1062 SGEN_ASSERT (0, MS_BLOCK_FOR_OBJ (obj) == MS_BLOCK_FOR_OBJ (ptr), "How can an object and a reference inside it not be in the same block?");
1065 sgen_los_mark_mod_union_card (obj, ptr);
1067 binary_protocol_mod_union_remset (obj, ptr, value_obj, SGEN_LOAD_VTABLE (value_obj));
1070 static inline gboolean
1071 major_block_is_evacuating (MSBlockInfo *block)
1073 if (evacuate_block_obj_sizes [block->obj_size_index] &&
1074 !block->has_pinned &&
1075 !block->is_to_space)
1080 #define LOAD_VTABLE SGEN_LOAD_VTABLE
1082 #define MS_MARK_OBJECT_AND_ENQUEUE_CHECKED(obj,desc,block,queue) do { \
1083 int __word, __bit; \
1084 MS_CALC_MARK_BIT (__word, __bit, (obj)); \
1085 if (!MS_MARK_BIT ((block), __word, __bit) && MS_OBJ_ALLOCED ((obj), (block))) { \
1086 MS_SET_MARK_BIT ((block), __word, __bit); \
1087 if (sgen_gc_descr_has_references (desc)) \
1088 GRAY_OBJECT_ENQUEUE ((queue), (obj), (desc)); \
1089 binary_protocol_mark ((obj), (gpointer)LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((obj))); \
1090 INC_NUM_MAJOR_OBJECTS_MARKED (); \
1093 #define MS_MARK_OBJECT_AND_ENQUEUE(obj,desc,block,queue) do { \
1094 int __word, __bit; \
1095 MS_CALC_MARK_BIT (__word, __bit, (obj)); \
1096 SGEN_ASSERT (9, MS_OBJ_ALLOCED ((obj), (block)), "object %p not allocated", obj); \
1097 if (!MS_MARK_BIT ((block), __word, __bit)) { \
1098 MS_SET_MARK_BIT ((block), __word, __bit); \
1099 if (sgen_gc_descr_has_references (desc)) \
1100 GRAY_OBJECT_ENQUEUE ((queue), (obj), (desc)); \
1101 binary_protocol_mark ((obj), (gpointer)LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((obj))); \
1102 INC_NUM_MAJOR_OBJECTS_MARKED (); \
1107 pin_major_object (GCObject *obj, SgenGrayQueue *queue)
1111 if (concurrent_mark)
1112 g_assert_not_reached ();
1114 block = MS_BLOCK_FOR_OBJ (obj);
1115 block->has_pinned = TRUE;
1116 MS_MARK_OBJECT_AND_ENQUEUE (obj, sgen_obj_get_descriptor (obj), block, queue);
1119 #include "sgen-major-copy-object.h"
1122 major_get_and_reset_num_major_objects_marked (void)
1124 #ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
1125 long long num = num_major_objects_marked;
1126 num_major_objects_marked = 0;
1133 #define PREFETCH_CARDS 1 /* BOOL FASTENABLE */
1135 #undef PREFETCH_CARDS
1138 /* gcc 4.2.1 from xcode4 crashes on sgen_card_table_get_card_address () when this is enabled */
1139 #if defined(PLATFORM_MACOSX)
1140 #define GCC_VERSION (__GNUC__ * 10000 \
1141 + __GNUC_MINOR__ * 100 \
1142 + __GNUC_PATCHLEVEL__)
1143 #if GCC_VERSION <= 40300
1144 #undef PREFETCH_CARDS
1148 #ifdef HEAVY_STATISTICS
1149 static guint64 stat_optimized_copy;
1150 static guint64 stat_optimized_copy_nursery;
1151 static guint64 stat_optimized_copy_nursery_forwarded;
1152 static guint64 stat_optimized_copy_nursery_pinned;
1153 static guint64 stat_optimized_copy_major;
1154 static guint64 stat_optimized_copy_major_small_fast;
1155 static guint64 stat_optimized_copy_major_small_slow;
1156 static guint64 stat_optimized_copy_major_large;
1157 static guint64 stat_optimized_copy_major_forwarded;
1158 static guint64 stat_optimized_copy_major_small_evacuate;
1159 static guint64 stat_optimized_major_scan;
1160 static guint64 stat_optimized_major_scan_no_refs;
1162 static guint64 stat_drain_prefetch_fills;
1163 static guint64 stat_drain_prefetch_fill_failures;
1164 static guint64 stat_drain_loops;
1167 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_no_evacuation
1168 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_no_evacuation
1169 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_no_evacuation
1170 #include "sgen-marksweep-drain-gray-stack.h"
1172 #define COPY_OR_MARK_WITH_EVACUATION
1173 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_with_evacuation
1174 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_with_evacuation
1175 #define SCAN_VTYPE_FUNCTION_NAME major_scan_vtype_with_evacuation
1176 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_with_evacuation
1177 #define SCAN_PTR_FIELD_FUNCTION_NAME major_scan_ptr_field_with_evacuation
1178 #include "sgen-marksweep-drain-gray-stack.h"
1180 #define COPY_OR_MARK_CONCURRENT
1181 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_concurrent_no_evacuation
1182 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_concurrent_no_evacuation
1183 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_concurrent_no_evacuation
1184 #include "sgen-marksweep-drain-gray-stack.h"
1186 #define COPY_OR_MARK_CONCURRENT_WITH_EVACUATION
1187 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_concurrent_with_evacuation
1188 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_concurrent_with_evacuation
1189 #define SCAN_VTYPE_FUNCTION_NAME major_scan_vtype_concurrent_with_evacuation
1190 #define SCAN_PTR_FIELD_FUNCTION_NAME major_scan_ptr_field_concurrent_with_evacuation
1191 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_concurrent_with_evacuation
1192 #include "sgen-marksweep-drain-gray-stack.h"
1194 static inline gboolean
1195 major_is_evacuating (void)
1198 for (i = 0; i < num_block_obj_sizes; ++i) {
1199 if (evacuate_block_obj_sizes [i]) {
1208 drain_gray_stack (SgenGrayQueue *queue)
1210 if (major_is_evacuating ())
1211 return drain_gray_stack_with_evacuation (queue);
1213 return drain_gray_stack_no_evacuation (queue);
1217 drain_gray_stack_concurrent (SgenGrayQueue *queue)
1219 if (major_is_evacuating ())
1220 return drain_gray_stack_concurrent_with_evacuation (queue);
1222 return drain_gray_stack_concurrent_no_evacuation (queue);
1226 major_copy_or_mark_object_canonical (GCObject **ptr, SgenGrayQueue *queue)
1228 major_copy_or_mark_object_with_evacuation (ptr, *ptr, queue);
1232 major_copy_or_mark_object_concurrent_canonical (GCObject **ptr, SgenGrayQueue *queue)
1234 major_copy_or_mark_object_concurrent_with_evacuation (ptr, *ptr, queue);
1238 major_copy_or_mark_object_concurrent_finish_canonical (GCObject **ptr, SgenGrayQueue *queue)
1240 major_copy_or_mark_object_with_evacuation (ptr, *ptr, queue);
1244 mark_pinned_objects_in_block (MSBlockInfo *block, size_t first_entry, size_t last_entry, SgenGrayQueue *queue)
1246 void **entry, **end;
1247 int last_index = -1;
1249 if (first_entry == last_entry)
1252 block->has_pinned = TRUE;
1254 entry = sgen_pinning_get_entry (first_entry);
1255 end = sgen_pinning_get_entry (last_entry);
1257 for (; entry < end; ++entry) {
1258 int index = MS_BLOCK_OBJ_INDEX (*entry, block);
1260 SGEN_ASSERT (9, index >= 0 && index < MS_BLOCK_FREE / block->obj_size, "invalid object %p index %d max-index %d", *entry, index, (int)(MS_BLOCK_FREE / block->obj_size));
1261 if (index == last_index)
1263 obj = MS_BLOCK_OBJ (block, index);
1264 MS_MARK_OBJECT_AND_ENQUEUE_CHECKED (obj, sgen_obj_get_descriptor (obj), block, queue);
1270 sweep_block_for_size (MSBlockInfo *block, int count, int obj_size)
1274 for (obj_index = 0; obj_index < count; ++obj_index) {
1276 void *obj = MS_BLOCK_OBJ_FOR_SIZE (block, obj_index, obj_size);
1278 MS_CALC_MARK_BIT (word, bit, obj);
1279 if (MS_MARK_BIT (block, word, bit)) {
1280 SGEN_ASSERT (9, MS_OBJ_ALLOCED (obj, block), "object %p not allocated", obj);
1282 /* an unmarked object */
1283 if (MS_OBJ_ALLOCED (obj, block)) {
1285 * FIXME: Merge consecutive
1286 * slots for lower reporting
1287 * overhead. Maybe memset
1288 * will also benefit?
1290 binary_protocol_empty (obj, obj_size);
1291 memset (obj, 0, obj_size);
1293 *(void**)obj = block->free_list;
1294 block->free_list = (void **)obj;
1299 static inline gboolean
1300 try_set_block_state (MSBlockInfo *block, gint32 new_state, gint32 expected_state)
1302 gint32 old_state = SGEN_CAS (&block->state, new_state, expected_state);
1303 gboolean success = old_state == expected_state;
1305 binary_protocol_block_set_state (block, MS_BLOCK_SIZE, old_state, new_state);
1310 set_block_state (MSBlockInfo *block, gint32 new_state, gint32 expected_state)
1312 SGEN_ASSERT (6, block->state == expected_state, "Block state incorrect before set");
1313 block->state = new_state;
1317 * If `block` needs sweeping, sweep it and return TRUE. Otherwise return FALSE.
1319 * Sweeping means iterating through the block's slots and building the free-list from the
1320 * unmarked ones. They will also be zeroed. The mark bits will be reset.
1323 sweep_block (MSBlockInfo *block)
1326 void *reversed = NULL;
1329 switch (block->state) {
1330 case BLOCK_STATE_SWEPT:
1332 case BLOCK_STATE_MARKING:
1333 case BLOCK_STATE_CHECKING:
1334 SGEN_ASSERT (0, FALSE, "How did we get to sweep a block that's being marked or being checked?");
1336 case BLOCK_STATE_SWEEPING:
1337 /* FIXME: Do this more elegantly */
1340 case BLOCK_STATE_NEED_SWEEPING:
1341 if (!try_set_block_state (block, BLOCK_STATE_SWEEPING, BLOCK_STATE_NEED_SWEEPING))
1345 SGEN_ASSERT (0, FALSE, "Illegal block state");
1348 SGEN_ASSERT (6, block->state == BLOCK_STATE_SWEEPING, "How did we get here without setting state to sweeping?");
1350 count = MS_BLOCK_FREE / block->obj_size;
1352 block->free_list = NULL;
1354 /* Use inline instances specialized to constant sizes, this allows the compiler to replace the memset calls with inline code */
1355 // FIXME: Add more sizes
1356 switch (block->obj_size) {
1358 sweep_block_for_size (block, count, 16);
1361 sweep_block_for_size (block, count, block->obj_size);
1365 /* reset mark bits */
1366 memset (block->mark_words, 0, sizeof (mword) * MS_NUM_MARK_WORDS);
1368 /* Reverse free list so that it's in address order */
1370 while (block->free_list) {
1371 void *next = *(void**)block->free_list;
1372 *(void**)block->free_list = reversed;
1373 reversed = block->free_list;
1374 block->free_list = (void **)next;
1376 block->free_list = (void **)reversed;
1378 mono_memory_write_barrier ();
1380 set_block_state (block, BLOCK_STATE_SWEPT, BLOCK_STATE_SWEEPING);
1391 if (sizeof (mword) == 8)
1392 count += __builtin_popcountll (d);
1394 count += __builtin_popcount (d);
1404 /* statistics for evacuation */
1405 static size_t *sweep_slots_available;
1406 static size_t *sweep_slots_used;
1407 static size_t *sweep_num_blocks;
1409 static volatile size_t num_major_sections_before_sweep;
1410 static volatile size_t num_major_sections_freed_in_sweep;
1417 for (i = 0; i < num_block_obj_sizes; ++i)
1418 sweep_slots_available [i] = sweep_slots_used [i] = sweep_num_blocks [i] = 0;
1420 /* clear all the free lists */
1421 for (i = 0; i < MS_BLOCK_TYPE_MAX; ++i) {
1422 MSBlockInfo * volatile *free_blocks = free_block_lists [i];
1424 for (j = 0; j < num_block_obj_sizes; ++j)
1425 free_blocks [j] = NULL;
1429 static void sweep_finish (void);
1432 * If `wait` is TRUE and the block is currently being checked, this function will wait until
1433 * the checking has finished.
1435 * Returns whether the block is still there. If `wait` is FALSE, the return value will not
1436 * be correct, i.e. must not be used.
1439 ensure_block_is_checked_for_sweeping (guint32 block_index, gboolean wait, gboolean *have_checked)
1442 gboolean have_live = FALSE;
1443 gboolean have_free = FALSE;
1449 volatile gpointer *block_slot = sgen_array_list_get_slot (&allocated_blocks, block_index);
1451 SGEN_ASSERT (6, sweep_in_progress (), "Why do we call this function if there's no sweep in progress?");
1454 *have_checked = FALSE;
1457 tagged_block = *(void * volatile *)block_slot;
1461 if (BLOCK_IS_TAGGED_CHECKING (tagged_block)) {
1464 /* FIXME: do this more elegantly */
1469 if (SGEN_CAS_PTR (block_slot, BLOCK_TAG_CHECKING (tagged_block), tagged_block) != tagged_block)
1472 block = BLOCK_UNTAG (tagged_block);
1473 block_state = block->state;
1475 if (!sweep_in_progress ()) {
1476 SGEN_ASSERT (6, block_state != BLOCK_STATE_SWEEPING && block_state != BLOCK_STATE_CHECKING, "Invalid block state.");
1478 SGEN_ASSERT (6, block_state != BLOCK_STATE_NEED_SWEEPING, "Invalid block state.");
1481 switch (block_state) {
1482 case BLOCK_STATE_SWEPT:
1483 case BLOCK_STATE_NEED_SWEEPING:
1484 case BLOCK_STATE_SWEEPING:
1486 case BLOCK_STATE_MARKING:
1488 case BLOCK_STATE_CHECKING:
1489 SGEN_ASSERT (0, FALSE, "We set the CHECKING bit - how can the stage be CHECKING?");
1492 SGEN_ASSERT (0, FALSE, "Illegal block state");
1496 SGEN_ASSERT (6, block->state == BLOCK_STATE_MARKING, "When we sweep all blocks must start out marking.");
1497 set_block_state (block, BLOCK_STATE_CHECKING, BLOCK_STATE_MARKING);
1500 *have_checked = TRUE;
1502 block->has_pinned = block->pinned;
1504 block->is_to_space = FALSE;
1506 count = MS_BLOCK_FREE / block->obj_size;
1508 if (block->cardtable_mod_union) {
1509 sgen_card_table_free_mod_union (block->cardtable_mod_union, MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE);
1510 block->cardtable_mod_union = NULL;
1513 /* Count marked objects in the block */
1514 for (i = 0; i < MS_NUM_MARK_WORDS; ++i)
1515 nused += bitcount (block->mark_words [i]);
1523 int obj_size_index = block->obj_size_index;
1524 gboolean has_pinned = block->has_pinned;
1526 set_block_state (block, BLOCK_STATE_NEED_SWEEPING, BLOCK_STATE_CHECKING);
1529 * FIXME: Go straight to SWEPT if there are no free slots. We need
1530 * to set the free slot list to NULL, though, and maybe update some
1534 sweep_block (block);
1537 ++sweep_num_blocks [obj_size_index];
1538 sweep_slots_used [obj_size_index] += nused;
1539 sweep_slots_available [obj_size_index] += count;
1543 * If there are free slots in the block, add
1544 * the block to the corresponding free list.
1547 MSBlockInfo * volatile *free_blocks = FREE_BLOCKS (block->pinned, block->has_references);
1550 SGEN_ASSERT (6, block->free_list, "How do we not have a free list when there are free slots?");
1552 add_free_block (free_blocks, obj_size_index, block);
1555 /* FIXME: Do we need the heap boundaries while we do nursery collections? */
1556 update_heap_boundaries_for_block (block);
1559 * Blocks without live objects are removed from the
1560 * block list and freed.
1562 SGEN_ASSERT (6, block_index < allocated_blocks.next_slot, "How did the number of blocks shrink?");
1563 SGEN_ASSERT (6, *block_slot == BLOCK_TAG_CHECKING (tagged_block), "How did the block move?");
1565 binary_protocol_empty (MS_BLOCK_OBJ (block, 0), (char*)MS_BLOCK_OBJ (block, count) - (char*)MS_BLOCK_OBJ (block, 0));
1566 ms_free_block (block);
1568 SGEN_ATOMIC_ADD_P (num_major_sections, -1);
1570 tagged_block = NULL;
1574 *block_slot = tagged_block;
1575 return !!tagged_block;
1579 sweep_job_func (void *thread_data_untyped, SgenThreadPoolJob *job)
1581 guint32 block_index;
1582 guint32 num_blocks = num_major_sections_before_sweep;
1584 SGEN_ASSERT (0, sweep_in_progress (), "Sweep thread called with wrong state");
1585 SGEN_ASSERT (0, num_blocks <= allocated_blocks.next_slot, "How did we lose blocks?");
1588 * We traverse the block array from high to low. Nursery collections will have to
1589 * cooperate with the sweep thread to finish sweeping, and they will traverse from
1590 * low to high, to avoid constantly colliding on the same blocks.
1592 for (block_index = num_blocks; block_index-- > 0;) {
1594 * The block might have been freed by another thread doing some checking
1597 if (!ensure_block_is_checked_for_sweeping (block_index, TRUE, NULL))
1598 ++num_major_sections_freed_in_sweep;
1601 while (!try_set_sweep_state (SWEEP_STATE_COMPACTING, SWEEP_STATE_SWEEPING)) {
1603 * The main GC thread is currently iterating over the block array to help us
1604 * finish the sweep. We have already finished, but we don't want to mess up
1605 * that iteration, so we just wait for it.
1610 if (SGEN_MAX_ASSERT_LEVEL >= 6) {
1611 for (block_index = num_blocks; block_index < allocated_blocks.next_slot; ++block_index) {
1612 MSBlockInfo *block = BLOCK_UNTAG (*sgen_array_list_get_slot (&allocated_blocks, block_index));
1613 SGEN_ASSERT (6, block && block->state == BLOCK_STATE_SWEPT, "How did a new block to be swept get added while swept?");
1617 sgen_array_list_remove_nulls (&allocated_blocks);
1629 for (i = 0; i < num_block_obj_sizes; ++i) {
1630 float usage = (float)sweep_slots_used [i] / (float)sweep_slots_available [i];
1631 if (sweep_num_blocks [i] > 5 && usage < evacuation_threshold) {
1632 evacuate_block_obj_sizes [i] = TRUE;
1634 g_print ("slot size %d - %d of %d used\n",
1635 block_obj_sizes [i], slots_used [i], slots_available [i]);
1638 evacuate_block_obj_sizes [i] = FALSE;
1642 sgen_memgov_major_post_sweep ();
1644 set_sweep_state (SWEEP_STATE_SWEPT, SWEEP_STATE_COMPACTING);
1650 set_sweep_state (SWEEP_STATE_SWEEPING, SWEEP_STATE_NEED_SWEEPING);
1654 SGEN_ASSERT (0, num_major_sections == allocated_blocks.next_slot, "We don't know how many blocks we have?");
1656 num_major_sections_before_sweep = num_major_sections;
1657 num_major_sections_freed_in_sweep = 0;
1659 SGEN_ASSERT (0, !sweep_job, "We haven't finished the last sweep?");
1660 if (concurrent_sweep) {
1661 sweep_job = sgen_thread_pool_job_alloc ("sweep", sweep_job_func, sizeof (SgenThreadPoolJob));
1662 sgen_thread_pool_job_enqueue (sweep_job);
1664 sweep_job_func (NULL, NULL);
1669 major_have_swept (void)
1671 return sweep_state == SWEEP_STATE_SWEPT;
1674 static int count_pinned_ref;
1675 static int count_pinned_nonref;
1676 static int count_nonpinned_ref;
1677 static int count_nonpinned_nonref;
1680 count_nonpinned_callback (GCObject *obj, size_t size, void *data)
1682 GCVTable vtable = LOAD_VTABLE (obj);
1684 if (SGEN_VTABLE_HAS_REFERENCES (vtable))
1685 ++count_nonpinned_ref;
1687 ++count_nonpinned_nonref;
1691 count_pinned_callback (GCObject *obj, size_t size, void *data)
1693 GCVTable vtable = LOAD_VTABLE (obj);
1695 if (SGEN_VTABLE_HAS_REFERENCES (vtable))
1698 ++count_pinned_nonref;
1701 static G_GNUC_UNUSED void
1702 count_ref_nonref_objs (void)
1706 count_pinned_ref = 0;
1707 count_pinned_nonref = 0;
1708 count_nonpinned_ref = 0;
1709 count_nonpinned_nonref = 0;
1711 major_iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED, count_nonpinned_callback, NULL);
1712 major_iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED, count_pinned_callback, NULL);
1714 total = count_pinned_nonref + count_nonpinned_nonref + count_pinned_ref + count_nonpinned_ref;
1716 g_print ("ref: %d pinned %d non-pinned non-ref: %d pinned %d non-pinned -- %.1f\n",
1717 count_pinned_ref, count_nonpinned_ref,
1718 count_pinned_nonref, count_nonpinned_nonref,
1719 (count_pinned_nonref + count_nonpinned_nonref) * 100.0 / total);
1723 ms_calculate_block_obj_sizes (double factor, int *arr)
1730 * Have every possible slot size starting with the minimal
1731 * object size up to and including four times that size. Then
1732 * proceed by increasing geometrically with the given factor.
1735 for (int size = SGEN_CLIENT_MINIMUM_OBJECT_SIZE; size <= 4 * SGEN_CLIENT_MINIMUM_OBJECT_SIZE; size += SGEN_ALLOC_ALIGN) {
1737 arr [num_sizes] = size;
1741 target_size = (double)last_size;
1744 int target_count = (int)floor (MS_BLOCK_FREE / target_size);
1745 int size = MIN ((MS_BLOCK_FREE / target_count) & ~(SGEN_ALLOC_ALIGN - 1), SGEN_MAX_SMALL_OBJ_SIZE);
1747 if (size != last_size) {
1749 arr [num_sizes] = size;
1754 target_size *= factor;
1755 } while (last_size < SGEN_MAX_SMALL_OBJ_SIZE);
1760 /* only valid during minor collections */
1761 static mword old_num_major_sections;
1764 major_start_nursery_collection (void)
1766 #ifdef MARKSWEEP_CONSISTENCY_CHECK
1767 consistency_check ();
1770 old_num_major_sections = num_major_sections;
1774 major_finish_nursery_collection (void)
1776 #ifdef MARKSWEEP_CONSISTENCY_CHECK
1777 consistency_check ();
1782 major_start_major_collection (void)
1787 major_finish_sweep_checking ();
1790 * Clear the free lists for block sizes where we do evacuation. For those block
1791 * sizes we will have to allocate new blocks.
1793 for (i = 0; i < num_block_obj_sizes; ++i) {
1794 if (!evacuate_block_obj_sizes [i])
1797 binary_protocol_evacuating_blocks (block_obj_sizes [i]);
1799 free_block_lists [0][i] = NULL;
1800 free_block_lists [MS_BLOCK_FLAG_REFS][i] = NULL;
1804 binary_protocol_sweep_begin (GENERATION_OLD, TRUE);
1806 /* Sweep all unswept blocks and set them to MARKING */
1807 FOREACH_BLOCK_NO_LOCK (block) {
1809 sweep_block (block);
1810 SGEN_ASSERT (0, block->state == BLOCK_STATE_SWEPT, "All blocks must be swept when we're pinning.");
1811 set_block_state (block, BLOCK_STATE_MARKING, BLOCK_STATE_SWEPT);
1812 } END_FOREACH_BLOCK_NO_LOCK;
1815 binary_protocol_sweep_end (GENERATION_OLD, TRUE);
1817 set_sweep_state (SWEEP_STATE_NEED_SWEEPING, SWEEP_STATE_SWEPT);
1821 major_finish_major_collection (ScannedObjectCounts *counts)
1823 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
1824 if (binary_protocol_is_enabled ()) {
1825 counts->num_scanned_objects = scanned_objects_list.next_slot;
1827 sgen_pointer_queue_sort_uniq (&scanned_objects_list);
1828 counts->num_unique_scanned_objects = scanned_objects_list.next_slot;
1830 sgen_pointer_queue_clear (&scanned_objects_list);
1835 #if SIZEOF_VOID_P != 8
1837 compare_pointers (const void *va, const void *vb) {
1838 char *a = *(char**)va, *b = *(char**)vb;
1848 * This is called with sweep completed and the world stopped.
1851 major_free_swept_blocks (size_t allowance)
1853 /* FIXME: This is probably too much. It's assuming all objects are small. */
1854 size_t section_reserve = allowance / MS_BLOCK_SIZE;
1856 SGEN_ASSERT (0, sweep_state == SWEEP_STATE_SWEPT, "Sweeping must have finished before freeing blocks");
1860 * sgen_free_os_memory () asserts in mono_vfree () because windows doesn't like freeing the middle of
1861 * a VirtualAlloc ()-ed block.
1866 #if SIZEOF_VOID_P != 8
1868 int i, num_empty_blocks_orig, num_blocks, arr_length;
1870 void **empty_block_arr;
1871 void **rebuild_next;
1873 if (num_empty_blocks <= section_reserve)
1875 SGEN_ASSERT (0, num_empty_blocks > 0, "section reserve can't be negative");
1877 num_empty_blocks_orig = num_empty_blocks;
1878 empty_block_arr = (void**)sgen_alloc_internal_dynamic (sizeof (void*) * num_empty_blocks_orig,
1879 INTERNAL_MEM_MS_BLOCK_INFO_SORT, FALSE);
1880 if (!empty_block_arr)
1884 for (block = empty_blocks; block; block = *(void**)block)
1885 empty_block_arr [i++] = block;
1886 SGEN_ASSERT (0, i == num_empty_blocks, "empty block count wrong");
1888 sgen_qsort (empty_block_arr, num_empty_blocks, sizeof (void*), compare_pointers);
1891 * We iterate over the free blocks, trying to find MS_BLOCK_ALLOC_NUM
1892 * contiguous ones. If we do, we free them. If that's not enough to get to
1893 * section_reserve, we halve the number of contiguous blocks we're looking
1894 * for and have another go, until we're done with looking for pairs of
1895 * blocks, at which point we give up and go to the fallback.
1897 arr_length = num_empty_blocks_orig;
1898 num_blocks = MS_BLOCK_ALLOC_NUM;
1899 while (num_empty_blocks > section_reserve && num_blocks > 1) {
1904 for (i = 0; i < arr_length; ++i) {
1906 void *block = empty_block_arr [i];
1907 SGEN_ASSERT (6, block, "we're not shifting correctly");
1909 empty_block_arr [dest] = block;
1911 * This is not strictly necessary, but we're
1914 empty_block_arr [i] = NULL;
1923 SGEN_ASSERT (6, first >= 0 && d > first, "algorithm is wrong");
1925 if ((char*)block != ((char*)empty_block_arr [d-1]) + MS_BLOCK_SIZE) {
1930 if (d + 1 - first == num_blocks) {
1932 * We found num_blocks contiguous blocks. Free them
1933 * and null their array entries. As an optimization
1934 * we could, instead of nulling the entries, shift
1935 * the following entries over to the left, while
1939 sgen_free_os_memory (empty_block_arr [first], MS_BLOCK_SIZE * num_blocks, SGEN_ALLOC_HEAP);
1940 for (j = first; j <= d; ++j)
1941 empty_block_arr [j] = NULL;
1945 num_empty_blocks -= num_blocks;
1947 stat_major_blocks_freed += num_blocks;
1948 if (num_blocks == MS_BLOCK_ALLOC_NUM)
1949 stat_major_blocks_freed_ideal += num_blocks;
1951 stat_major_blocks_freed_less_ideal += num_blocks;
1956 SGEN_ASSERT (6, dest <= i && dest <= arr_length, "array length is off");
1958 SGEN_ASSERT (6, arr_length == num_empty_blocks, "array length is off");
1963 /* rebuild empty_blocks free list */
1964 rebuild_next = (void**)&empty_blocks;
1965 for (i = 0; i < arr_length; ++i) {
1966 void *block = empty_block_arr [i];
1967 SGEN_ASSERT (6, block, "we're missing blocks");
1968 *rebuild_next = block;
1969 rebuild_next = (void**)block;
1971 *rebuild_next = NULL;
1974 sgen_free_internal_dynamic (empty_block_arr, sizeof (void*) * num_empty_blocks_orig, INTERNAL_MEM_MS_BLOCK_INFO_SORT);
1977 SGEN_ASSERT (0, num_empty_blocks >= 0, "we freed more blocks than we had in the first place?");
1981 * This is our threshold. If there's not more empty than used blocks, we won't
1982 * release uncontiguous blocks, in fear of fragmenting the address space.
1984 if (num_empty_blocks <= num_major_sections)
1988 while (num_empty_blocks > section_reserve) {
1989 void *next = *(void**)empty_blocks;
1990 sgen_free_os_memory (empty_blocks, MS_BLOCK_SIZE, SGEN_ALLOC_HEAP);
1991 empty_blocks = next;
1993 * Needs not be atomic because this is running
1998 ++stat_major_blocks_freed;
1999 #if SIZEOF_VOID_P != 8
2000 ++stat_major_blocks_freed_individual;
2006 major_pin_objects (SgenGrayQueue *queue)
2010 FOREACH_BLOCK_NO_LOCK (block) {
2011 size_t first_entry, last_entry;
2012 SGEN_ASSERT (6, block_is_swept_or_marking (block), "All blocks must be swept when we're pinning.");
2013 sgen_find_optimized_pin_queue_area (MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SKIP, MS_BLOCK_FOR_BLOCK_INFO (block) + MS_BLOCK_SIZE,
2014 &first_entry, &last_entry);
2015 mark_pinned_objects_in_block (block, first_entry, last_entry, queue);
2016 } END_FOREACH_BLOCK_NO_LOCK;
2020 major_init_to_space (void)
2025 major_report_pinned_memory_usage (void)
2027 g_assert_not_reached ();
2031 major_get_used_size (void)
2037 * We're holding the GC lock, but the sweep thread might be running. Make sure it's
2038 * finished, then we can iterate over the block array.
2040 major_finish_sweep_checking ();
2042 FOREACH_BLOCK_NO_LOCK (block) {
2043 int count = MS_BLOCK_FREE / block->obj_size;
2045 size += count * block->obj_size;
2046 for (iter = block->free_list; iter; iter = (void**)*iter)
2047 size -= block->obj_size;
2048 } END_FOREACH_BLOCK_NO_LOCK;
2053 /* FIXME: return number of bytes, not of sections */
2055 get_num_major_sections (void)
2057 return num_major_sections;
2061 * Returns the number of bytes in blocks that were present when the last sweep was
2062 * initiated, and were not freed during the sweep. They are the basis for calculating the
2066 get_bytes_survived_last_sweep (void)
2068 SGEN_ASSERT (0, sweep_state == SWEEP_STATE_SWEPT, "Can only query unswept sections after sweep");
2069 return (num_major_sections_before_sweep - num_major_sections_freed_in_sweep) * MS_BLOCK_SIZE;
2073 major_handle_gc_param (const char *opt)
2075 if (g_str_has_prefix (opt, "evacuation-threshold=")) {
2076 const char *arg = strchr (opt, '=') + 1;
2077 int percentage = atoi (arg);
2078 if (percentage < 0 || percentage > 100) {
2079 fprintf (stderr, "evacuation-threshold must be an integer in the range 0-100.\n");
2082 evacuation_threshold = (float)percentage / 100.0f;
2084 } else if (!strcmp (opt, "lazy-sweep")) {
2087 } else if (!strcmp (opt, "no-lazy-sweep")) {
2090 } else if (!strcmp (opt, "concurrent-sweep")) {
2091 concurrent_sweep = TRUE;
2093 } else if (!strcmp (opt, "no-concurrent-sweep")) {
2094 concurrent_sweep = FALSE;
2102 major_print_gc_param_usage (void)
2106 " evacuation-threshold=P (where P is a percentage, an integer in 0-100)\n"
2107 " (no-)lazy-sweep\n"
2108 " (no-)concurrent-sweep\n"
2113 * This callback is used to clear cards, move cards to the shadow table and do counting.
2116 major_iterate_live_block_ranges (sgen_cardtable_block_callback callback)
2119 gboolean has_references;
2121 major_finish_sweep_checking ();
2122 FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK (block, has_references) {
2124 callback ((mword)MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE);
2125 } END_FOREACH_BLOCK_NO_LOCK;
2128 #ifdef HEAVY_STATISTICS
2129 extern guint64 marked_cards;
2130 extern guint64 scanned_cards;
2131 extern guint64 scanned_objects;
2132 extern guint64 remarked_cards;
2135 #define CARD_WORDS_PER_BLOCK (CARDS_PER_BLOCK / SIZEOF_VOID_P)
2137 * MS blocks are 16K aligned.
2138 * Cardtables are 4K aligned, at least.
2139 * This means that the cardtable of a given block is 32 bytes aligned.
2142 initial_skip_card (guint8 *card_data)
2144 mword *cards = (mword*)card_data;
2147 for (i = 0; i < CARD_WORDS_PER_BLOCK; ++i) {
2153 if (i == CARD_WORDS_PER_BLOCK)
2154 return card_data + CARDS_PER_BLOCK;
2156 #if defined(__i386__) && defined(__GNUC__)
2157 return card_data + i * 4 + (__builtin_ffs (card) - 1) / 8;
2158 #elif defined(__x86_64__) && defined(__GNUC__)
2159 return card_data + i * 8 + (__builtin_ffsll (card) - 1) / 8;
2160 #elif defined(__s390x__) && defined(__GNUC__)
2161 return card_data + i * 8 + (__builtin_ffsll (GUINT64_TO_LE(card)) - 1) / 8;
2163 for (i = i * SIZEOF_VOID_P; i < CARDS_PER_BLOCK; ++i) {
2165 return &card_data [i];
2171 #define MS_BLOCK_OBJ_INDEX_FAST(o,b,os) (((char*)(o) - ((b) + MS_BLOCK_SKIP)) / (os))
2172 #define MS_BLOCK_OBJ_FAST(b,os,i) ((b) + MS_BLOCK_SKIP + (os) * (i))
2173 #define MS_OBJ_ALLOCED_FAST(o,b) (*(void**)(o) && (*(char**)(o) < (b) || *(char**)(o) >= (b) + MS_BLOCK_SIZE))
2176 scan_card_table_for_block (MSBlockInfo *block, CardTableScanType scan_type, ScanCopyContext ctx)
2178 SgenGrayQueue *queue = ctx.queue;
2179 ScanObjectFunc scan_func = ctx.ops->scan_object;
2180 #ifndef SGEN_HAVE_OVERLAPPING_CARDS
2181 guint8 cards_copy [CARDS_PER_BLOCK];
2183 guint8 cards_preclean [CARDS_PER_BLOCK];
2184 gboolean small_objects;
2187 guint8 *card_data, *card_base;
2188 guint8 *card_data_end;
2189 char *scan_front = NULL;
2191 /* The concurrent mark doesn't enter evacuating blocks */
2192 if (scan_type == CARDTABLE_SCAN_MOD_UNION_PRECLEAN && major_block_is_evacuating (block))
2195 block_obj_size = block->obj_size;
2196 small_objects = block_obj_size < CARD_SIZE_IN_BYTES;
2198 block_start = MS_BLOCK_FOR_BLOCK_INFO (block);
2201 * This is safe in face of card aliasing for the following reason:
2203 * Major blocks are 16k aligned, or 32 cards aligned.
2204 * Cards aliasing happens in powers of two, so as long as major blocks are aligned to their
2205 * sizes, they won't overflow the cardtable overlap modulus.
2207 if (scan_type & CARDTABLE_SCAN_MOD_UNION) {
2208 card_data = card_base = block->cardtable_mod_union;
2210 * This happens when the nursery collection that precedes finishing
2211 * the concurrent collection allocates new major blocks.
2216 if (scan_type == CARDTABLE_SCAN_MOD_UNION_PRECLEAN) {
2217 sgen_card_table_preclean_mod_union (card_data, cards_preclean, CARDS_PER_BLOCK);
2218 card_data = card_base = cards_preclean;
2221 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2222 card_data = card_base = sgen_card_table_get_card_scan_address ((mword)block_start);
2224 if (!sgen_card_table_get_card_data (cards_copy, (mword)block_start, CARDS_PER_BLOCK))
2226 card_data = card_base = cards_copy;
2229 card_data_end = card_data + CARDS_PER_BLOCK;
2231 card_data += MS_BLOCK_SKIP >> CARD_BITS;
2233 card_data = initial_skip_card (card_data);
2234 while (card_data < card_data_end) {
2235 size_t card_index, first_object_index;
2238 char *first_obj, *obj;
2240 HEAVY_STAT (++scanned_cards);
2247 card_index = card_data - card_base;
2248 start = (char*)(block_start + card_index * CARD_SIZE_IN_BYTES);
2249 end = start + CARD_SIZE_IN_BYTES;
2251 if (!block_is_swept_or_marking (block))
2252 sweep_block (block);
2254 HEAVY_STAT (++marked_cards);
2257 sgen_card_table_prepare_card_for_scanning (card_data);
2260 * If the card we're looking at starts at or in the block header, we
2261 * must start at the first object in the block, without calculating
2262 * the index of the object we're hypothetically starting at, because
2263 * it would be negative.
2265 if (card_index <= (MS_BLOCK_SKIP >> CARD_BITS))
2266 first_object_index = 0;
2268 first_object_index = MS_BLOCK_OBJ_INDEX_FAST (start, block_start, block_obj_size);
2270 obj = first_obj = (char*)MS_BLOCK_OBJ_FAST (block_start, block_obj_size, first_object_index);
2272 binary_protocol_card_scan (first_obj, end - first_obj);
2275 if (obj < scan_front || !MS_OBJ_ALLOCED_FAST (obj, block_start))
2278 if (scan_type & CARDTABLE_SCAN_MOD_UNION) {
2279 /* FIXME: do this more efficiently */
2281 MS_CALC_MARK_BIT (w, b, obj);
2282 if (!MS_MARK_BIT (block, w, b))
2286 GCObject *object = (GCObject*)obj;
2288 if (small_objects) {
2289 HEAVY_STAT (++scanned_objects);
2290 scan_func (object, sgen_obj_get_descriptor (object), queue);
2292 size_t offset = sgen_card_table_get_card_offset (obj, block_start);
2293 sgen_cardtable_scan_object (object, block_obj_size, card_base + offset, ctx);
2296 obj += block_obj_size;
2297 g_assert (scan_front <= obj);
2301 HEAVY_STAT (if (*card_data) ++remarked_cards);
2306 card_data = card_base + sgen_card_table_get_card_offset (obj, block_start);
2311 major_scan_card_table (CardTableScanType scan_type, ScanCopyContext ctx)
2314 gboolean has_references;
2316 if (!concurrent_mark)
2317 g_assert (scan_type == CARDTABLE_SCAN_GLOBAL);
2319 major_finish_sweep_checking ();
2320 binary_protocol_major_card_table_scan_start (sgen_timestamp (), scan_type & CARDTABLE_SCAN_MOD_UNION);
2321 FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK (block, has_references) {
2322 #ifdef PREFETCH_CARDS
2323 int prefetch_index = __index + 6;
2324 if (prefetch_index < allocated_blocks.next_slot) {
2325 MSBlockInfo *prefetch_block = BLOCK_UNTAG (*sgen_array_list_get_slot (&allocated_blocks, prefetch_index));
2326 PREFETCH_READ (prefetch_block);
2327 if (scan_type == CARDTABLE_SCAN_GLOBAL) {
2328 guint8 *prefetch_cards = sgen_card_table_get_card_scan_address ((mword)MS_BLOCK_FOR_BLOCK_INFO (prefetch_block));
2329 PREFETCH_WRITE (prefetch_cards);
2330 PREFETCH_WRITE (prefetch_cards + 32);
2335 if (!has_references)
2338 scan_card_table_for_block (block, scan_type, ctx);
2339 } END_FOREACH_BLOCK_NO_LOCK;
2340 binary_protocol_major_card_table_scan_end (sgen_timestamp (), scan_type & CARDTABLE_SCAN_MOD_UNION);
2344 major_count_cards (long long *num_total_cards, long long *num_marked_cards)
2347 gboolean has_references;
2348 long long total_cards = 0;
2349 long long marked_cards = 0;
2351 if (sweep_in_progress ()) {
2352 *num_total_cards = -1;
2353 *num_marked_cards = -1;
2357 FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK (block, has_references) {
2358 guint8 *cards = sgen_card_table_get_card_scan_address ((mword) MS_BLOCK_FOR_BLOCK_INFO (block));
2361 if (!has_references)
2364 total_cards += CARDS_PER_BLOCK;
2365 for (i = 0; i < CARDS_PER_BLOCK; ++i) {
2369 } END_FOREACH_BLOCK_NO_LOCK;
2371 *num_total_cards = total_cards;
2372 *num_marked_cards = marked_cards;
2376 update_cardtable_mod_union (void)
2380 FOREACH_BLOCK_NO_LOCK (block) {
2382 guint8 *mod_union = get_cardtable_mod_union_for_block (block, TRUE);
2383 sgen_card_table_update_mod_union (mod_union, MS_BLOCK_FOR_BLOCK_INFO (block), MS_BLOCK_SIZE, &num_cards);
2384 SGEN_ASSERT (6, num_cards == CARDS_PER_BLOCK, "Number of cards calculation is wrong");
2385 } END_FOREACH_BLOCK_NO_LOCK;
2388 #undef pthread_create
2391 post_param_init (SgenMajorCollector *collector)
2393 collector->sweeps_lazily = lazy_sweep;
2394 collector->needs_thread_pool = concurrent_mark || concurrent_sweep;
2398 sgen_marksweep_init_internal (SgenMajorCollector *collector, gboolean is_concurrent)
2402 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_MS_BLOCK_INFO, sizeof (MSBlockInfo));
2404 num_block_obj_sizes = ms_calculate_block_obj_sizes (MS_BLOCK_OBJ_SIZE_FACTOR, NULL);
2405 block_obj_sizes = (int *)sgen_alloc_internal_dynamic (sizeof (int) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
2406 ms_calculate_block_obj_sizes (MS_BLOCK_OBJ_SIZE_FACTOR, block_obj_sizes);
2408 evacuate_block_obj_sizes = (gboolean *)sgen_alloc_internal_dynamic (sizeof (gboolean) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
2409 for (i = 0; i < num_block_obj_sizes; ++i)
2410 evacuate_block_obj_sizes [i] = FALSE;
2412 sweep_slots_available = (size_t *)sgen_alloc_internal_dynamic (sizeof (size_t) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
2413 sweep_slots_used = (size_t *)sgen_alloc_internal_dynamic (sizeof (size_t) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
2414 sweep_num_blocks = (size_t *)sgen_alloc_internal_dynamic (sizeof (size_t) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
2419 g_print ("block object sizes:\n");
2420 for (i = 0; i < num_block_obj_sizes; ++i)
2421 g_print ("%d\n", block_obj_sizes [i]);
2425 for (i = 0; i < MS_BLOCK_TYPE_MAX; ++i)
2426 free_block_lists [i] = (MSBlockInfo *volatile *)sgen_alloc_internal_dynamic (sizeof (MSBlockInfo*) * num_block_obj_sizes, INTERNAL_MEM_MS_TABLES, TRUE);
2428 for (i = 0; i < MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES; ++i)
2429 fast_block_obj_size_indexes [i] = ms_find_block_obj_size_index (i * 8);
2430 for (i = 0; i < MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES * 8; ++i)
2431 g_assert (MS_BLOCK_OBJ_SIZE_INDEX (i) == ms_find_block_obj_size_index (i));
2433 mono_counters_register ("# major blocks allocated", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_alloced);
2434 mono_counters_register ("# major blocks freed", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed);
2435 mono_counters_register ("# major blocks lazy swept", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_lazy_swept);
2436 #if SIZEOF_VOID_P != 8
2437 mono_counters_register ("# major blocks freed ideally", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed_ideal);
2438 mono_counters_register ("# major blocks freed less ideally", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed_less_ideal);
2439 mono_counters_register ("# major blocks freed individually", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_freed_individual);
2440 mono_counters_register ("# major blocks allocated less ideally", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_major_blocks_alloced_less_ideal);
2443 collector->section_size = MAJOR_SECTION_SIZE;
2445 concurrent_mark = is_concurrent;
2446 collector->is_concurrent = is_concurrent;
2447 collector->needs_thread_pool = is_concurrent || concurrent_sweep;
2448 collector->get_and_reset_num_major_objects_marked = major_get_and_reset_num_major_objects_marked;
2449 collector->supports_cardtable = TRUE;
2451 collector->alloc_heap = major_alloc_heap;
2452 collector->is_object_live = major_is_object_live;
2453 collector->alloc_small_pinned_obj = major_alloc_small_pinned_obj;
2454 collector->alloc_degraded = major_alloc_degraded;
2456 collector->alloc_object = major_alloc_object;
2457 collector->free_pinned_object = free_pinned_object;
2458 collector->iterate_objects = major_iterate_objects;
2459 collector->free_non_pinned_object = major_free_non_pinned_object;
2460 collector->pin_objects = major_pin_objects;
2461 collector->pin_major_object = pin_major_object;
2462 collector->scan_card_table = major_scan_card_table;
2463 collector->iterate_live_block_ranges = major_iterate_live_block_ranges;
2464 if (is_concurrent) {
2465 collector->update_cardtable_mod_union = update_cardtable_mod_union;
2466 collector->get_cardtable_mod_union_for_reference = major_get_cardtable_mod_union_for_reference;
2468 collector->init_to_space = major_init_to_space;
2469 collector->sweep = major_sweep;
2470 collector->have_swept = major_have_swept;
2471 collector->finish_sweeping = major_finish_sweep_checking;
2472 collector->free_swept_blocks = major_free_swept_blocks;
2473 collector->check_scan_starts = major_check_scan_starts;
2474 collector->dump_heap = major_dump_heap;
2475 collector->get_used_size = major_get_used_size;
2476 collector->start_nursery_collection = major_start_nursery_collection;
2477 collector->finish_nursery_collection = major_finish_nursery_collection;
2478 collector->start_major_collection = major_start_major_collection;
2479 collector->finish_major_collection = major_finish_major_collection;
2480 collector->ptr_is_in_non_pinned_space = major_ptr_is_in_non_pinned_space;
2481 collector->ptr_is_from_pinned_alloc = ptr_is_from_pinned_alloc;
2482 collector->report_pinned_memory_usage = major_report_pinned_memory_usage;
2483 collector->get_num_major_sections = get_num_major_sections;
2484 collector->get_bytes_survived_last_sweep = get_bytes_survived_last_sweep;
2485 collector->handle_gc_param = major_handle_gc_param;
2486 collector->print_gc_param_usage = major_print_gc_param_usage;
2487 collector->post_param_init = post_param_init;
2488 collector->is_valid_object = major_is_valid_object;
2489 collector->describe_pointer = major_describe_pointer;
2490 collector->count_cards = major_count_cards;
2492 collector->major_ops_serial.copy_or_mark_object = major_copy_or_mark_object_canonical;
2493 collector->major_ops_serial.scan_object = major_scan_object_with_evacuation;
2494 collector->major_ops_serial.drain_gray_stack = drain_gray_stack;
2495 if (is_concurrent) {
2496 collector->major_ops_concurrent_start.copy_or_mark_object = major_copy_or_mark_object_concurrent_canonical;
2497 collector->major_ops_concurrent_start.scan_object = major_scan_object_concurrent_with_evacuation;
2498 collector->major_ops_concurrent_start.scan_vtype = major_scan_vtype_concurrent_with_evacuation;
2499 collector->major_ops_concurrent_start.scan_ptr_field = major_scan_ptr_field_concurrent_with_evacuation;
2500 collector->major_ops_concurrent_start.drain_gray_stack = drain_gray_stack_concurrent;
2502 collector->major_ops_concurrent_finish.copy_or_mark_object = major_copy_or_mark_object_concurrent_finish_canonical;
2503 collector->major_ops_concurrent_finish.scan_object = major_scan_object_with_evacuation;
2504 collector->major_ops_concurrent_finish.scan_vtype = major_scan_vtype_with_evacuation;
2505 collector->major_ops_concurrent_finish.scan_ptr_field = major_scan_ptr_field_with_evacuation;
2506 collector->major_ops_concurrent_finish.drain_gray_stack = drain_gray_stack;
2509 #ifdef HEAVY_STATISTICS
2510 mono_counters_register ("Optimized copy", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy);
2511 mono_counters_register ("Optimized copy nursery", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_nursery);
2512 mono_counters_register ("Optimized copy nursery forwarded", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_nursery_forwarded);
2513 mono_counters_register ("Optimized copy nursery pinned", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_nursery_pinned);
2514 mono_counters_register ("Optimized copy major", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major);
2515 mono_counters_register ("Optimized copy major small fast", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_small_fast);
2516 mono_counters_register ("Optimized copy major small slow", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_small_slow);
2517 mono_counters_register ("Optimized copy major small evacuate", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_small_evacuate);
2518 mono_counters_register ("Optimized copy major large", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_copy_major_large);
2519 mono_counters_register ("Optimized major scan", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_major_scan);
2520 mono_counters_register ("Optimized major scan no refs", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_optimized_major_scan_no_refs);
2522 mono_counters_register ("Gray stack drain loops", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_drain_loops);
2523 mono_counters_register ("Gray stack prefetch fills", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_drain_prefetch_fills);
2524 mono_counters_register ("Gray stack prefetch failures", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_drain_prefetch_fill_failures);
2527 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2528 mono_os_mutex_init (&scanned_objects_list_lock);
2531 SGEN_ASSERT (0, SGEN_MAX_SMALL_OBJ_SIZE <= MS_BLOCK_FREE / 2, "MAX_SMALL_OBJ_SIZE must be at most MS_BLOCK_FREE / 2");
2533 /*cardtable requires major pages to be 8 cards aligned*/
2534 g_assert ((MS_BLOCK_SIZE % (8 * CARD_SIZE_IN_BYTES)) == 0);
2538 sgen_marksweep_init (SgenMajorCollector *collector)
2540 sgen_marksweep_init_internal (collector, FALSE);
2544 sgen_marksweep_conc_init (SgenMajorCollector *collector)
2546 sgen_marksweep_init_internal (collector, TRUE);