3 * The Mark & Sweep major collector.
6 * Mark Probst <mark.probst@gmail.com>
8 * Copyright 2009-2010 Novell, Inc.
9 * Copyright (C) 2012 Xamarin Inc
11 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
23 #include "mono/sgen/sgen-gc.h"
24 #include "mono/sgen/sgen-protocol.h"
25 #include "mono/sgen/sgen-cardtable.h"
26 #include "mono/sgen/sgen-memory-governor.h"
27 #include "mono/sgen/sgen-layout-stats.h"
28 #include "mono/sgen/sgen-pointer-queue.h"
29 #include "mono/sgen/sgen-array-list.h"
30 #include "mono/sgen/sgen-pinning.h"
31 #include "mono/sgen/sgen-workers.h"
32 #include "mono/sgen/sgen-thread-pool.h"
33 #include "mono/sgen/sgen-client.h"
34 #include "mono/utils/mono-memory-model.h"
35 #include "mono/utils/mono-proclib.h"
37 static int ms_block_size
;
40 * Blocks must be at least this size, meaning that if we detect a
41 * page size lower than this, we'll use this instead.
43 #define MS_BLOCK_SIZE_MIN (1024 * 16)
45 #define CARDS_PER_BLOCK (ms_block_size / CARD_SIZE_IN_BYTES)
48 * Don't allocate single blocks, but alloc a contingent of this many
49 * blocks in one swoop. This must be a power of two.
51 #define MS_BLOCK_ALLOC_NUM 32
53 #define MS_NUM_MARK_WORDS ((ms_block_size / SGEN_ALLOC_ALIGN + sizeof (guint32) * 8 - 1) / (sizeof (guint32) * 8))
56 * Use this instead of sizeof (MSBlockInfo) since the mark_words
57 * array size depends on page size at runtime.
59 #define SIZEOF_MS_BLOCK_INFO (sizeof (MSBlockInfo) + sizeof (guint32) * (MS_NUM_MARK_WORDS - MONO_ZERO_LEN_ARRAY))
62 * Number of bytes before the first object in a block. At the start
63 * of a block is the MSBlockHeader, then opional padding, then come
64 * the objects, so this must be >= SIZEOF_MS_BLOCK_INFO.
66 #define MS_BLOCK_SKIP ((SIZEOF_MS_BLOCK_INFO + 15) & ~15)
68 #define MS_BLOCK_FREE (ms_block_size - MS_BLOCK_SKIP)
71 * Blocks progress from one state to the next:
73 * SWEPT The block is fully swept. It might or might not be in
76 * MARKING The block might or might not contain live objects. If
77 * we're in between an initial collection pause and the
78 * finishing pause, the block might or might not be in a
81 * CHECKING The sweep thread is investigating the block to determine
82 * whether or not it contains live objects. The block is
85 * NEED_SWEEPING The block contains live objects but has not yet been
86 * swept. It also contains free slots. It is in a block
89 * SWEEPING The block is being swept. It might be in a free list.
96 BLOCK_STATE_NEED_SWEEPING
,
100 typedef struct _MSBlockInfo MSBlockInfo
;
101 struct _MSBlockInfo
{
104 * FIXME: Do we even need this? It's only used during sweep and might be worth
105 * recalculating to save the space.
107 guint16 obj_size_index
;
108 /* FIXME: Reduce this - it only needs a byte. */
109 volatile gint32 state
;
111 unsigned int pinned
: 1;
112 unsigned int has_references
: 1;
113 unsigned int has_pinned
: 1; /* means cannot evacuate */
114 unsigned int is_to_space
: 1;
115 void ** volatile free_list
;
116 MSBlockInfo
* volatile next_free
;
117 guint8
* volatile cardtable_mod_union
;
118 guint32 mark_words
[MONO_ZERO_LEN_ARRAY
];
121 #define MS_BLOCK_FOR_BLOCK_INFO(b) ((char*)(b))
123 #define MS_BLOCK_OBJ(b,i) ((GCObject *)(MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP + (b)->obj_size * (i)))
124 #define MS_BLOCK_OBJ_FOR_SIZE(b,i,obj_size) (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP + (obj_size) * (i))
125 #define MS_BLOCK_DATA_FOR_OBJ(o) ((char*)((mword)(o) & ~(mword)(ms_block_size - 1)))
131 #define MS_BLOCK_FOR_OBJ(o) (&((MSBlockHeader*)MS_BLOCK_DATA_FOR_OBJ ((o)))->info)
133 /* object index will always be small */
134 #define MS_BLOCK_OBJ_INDEX(o,b) ((int)(((char*)(o) - (MS_BLOCK_FOR_BLOCK_INFO(b) + MS_BLOCK_SKIP)) / (b)->obj_size))
136 //casting to int is fine since blocks are 32k
137 #define MS_CALC_MARK_BIT(w,b,o) do { \
138 int i = ((int)((char*)(o) - MS_BLOCK_DATA_FOR_OBJ ((o)))) >> SGEN_ALLOC_ALIGN_BITS; \
143 #define MS_MARK_BIT(bl,w,b) ((bl)->mark_words [(w)] & (ONE_P << (b)))
144 #define MS_SET_MARK_BIT(bl,w,b) ((bl)->mark_words [(w)] |= (ONE_P << (b)))
145 #define MS_SET_MARK_BIT_PAR(bl,w,b,first) do { \
146 guint32 tmp_mark_word = (bl)->mark_words [(w)]; \
147 guint32 old_mark_word; \
149 while (!(tmp_mark_word & (ONE_P << (b)))) { \
150 old_mark_word = tmp_mark_word; \
151 tmp_mark_word = InterlockedCompareExchange ((volatile gint32*)&(bl)->mark_words [w], old_mark_word | (ONE_P << (b)), old_mark_word); \
152 if (tmp_mark_word == old_mark_word) { \
160 #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))
162 #define MS_BLOCK_OBJ_SIZE_FACTOR (pow (2.0, 1.0 / 3))
165 * This way we can lookup block object size indexes for sizes up to
166 * 256 bytes with a single load.
168 #define MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES 32
170 static int *block_obj_sizes
;
171 static int num_block_obj_sizes
;
172 static int fast_block_obj_size_indexes
[MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES
];
174 #define MS_BLOCK_FLAG_PINNED 1
175 #define MS_BLOCK_FLAG_REFS 2
177 #define MS_BLOCK_TYPE_MAX 4
179 static gboolean
*evacuate_block_obj_sizes
;
180 static float evacuation_threshold
= 0.666f
;
182 static gboolean lazy_sweep
= TRUE
;
186 SWEEP_STATE_NEED_SWEEPING
,
187 SWEEP_STATE_SWEEPING
,
188 SWEEP_STATE_SWEEPING_AND_ITERATING
,
189 SWEEP_STATE_COMPACTING
192 static volatile int sweep_state
= SWEEP_STATE_SWEPT
;
194 static gboolean concurrent_mark
;
195 static gboolean concurrent_sweep
= TRUE
;
197 int sweep_pool_context
= -1;
199 #define BLOCK_IS_TAGGED_HAS_REFERENCES(bl) SGEN_POINTER_IS_TAGGED_1 ((bl))
200 #define BLOCK_TAG_HAS_REFERENCES(bl) SGEN_POINTER_TAG_1 ((bl))
202 #define BLOCK_IS_TAGGED_CHECKING(bl) SGEN_POINTER_IS_TAGGED_2 ((bl))
203 #define BLOCK_TAG_CHECKING(bl) SGEN_POINTER_TAG_2 ((bl))
205 #define BLOCK_UNTAG(bl) ((MSBlockInfo *)SGEN_POINTER_UNTAG_12 ((bl)))
207 #define BLOCK_TAG(bl) ((bl)->has_references ? BLOCK_TAG_HAS_REFERENCES ((bl)) : (bl))
209 /* all allocated blocks in the system */
210 static SgenArrayList allocated_blocks
= SGEN_ARRAY_LIST_INIT (NULL
, sgen_array_list_default_is_slot_set
, sgen_array_list_default_cas_setter
, INTERNAL_MEM_PIN_QUEUE
);
212 /* non-allocated block free-list */
213 static void *empty_blocks
= NULL
;
214 static size_t num_empty_blocks
= 0;
215 static gboolean compact_blocks
= FALSE
;
218 * We can iterate the block list also while sweep is in progress but we
219 * need to account for blocks that will be checked for sweeping and even
220 * freed in the process.
222 #define FOREACH_BLOCK_NO_LOCK(bl) { \
223 volatile gpointer *slot; \
224 SGEN_ARRAY_LIST_FOREACH_SLOT (&allocated_blocks, slot) { \
225 (bl) = BLOCK_UNTAG (*slot); \
228 #define FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK(bl,hr) { \
229 volatile gpointer *slot; \
230 SGEN_ARRAY_LIST_FOREACH_SLOT (&allocated_blocks, slot) { \
231 (bl) = (MSBlockInfo *) (*slot); \
234 (hr) = BLOCK_IS_TAGGED_HAS_REFERENCES ((bl)); \
235 (bl) = BLOCK_UNTAG ((bl));
236 #define END_FOREACH_BLOCK_NO_LOCK } SGEN_ARRAY_LIST_END_FOREACH_SLOT; }
238 #define FOREACH_BLOCK_RANGE_HAS_REFERENCES_NO_LOCK(bl,begin,end,index,hr) { \
239 volatile gpointer *slot; \
240 SGEN_ARRAY_LIST_FOREACH_SLOT_RANGE (&allocated_blocks, begin, end, slot, index) { \
241 (bl) = (MSBlockInfo *) (*slot); \
244 (hr) = BLOCK_IS_TAGGED_HAS_REFERENCES ((bl)); \
245 (bl) = BLOCK_UNTAG ((bl));
246 #define END_FOREACH_BLOCK_RANGE_NO_LOCK } SGEN_ARRAY_LIST_END_FOREACH_SLOT_RANGE; }
248 static volatile size_t num_major_sections
= 0;
250 * One free block list for each block object size. We add and remove blocks from these
251 * lists lock-free via CAS.
253 * Blocks accessed/removed from `free_block_lists`:
254 * from the mutator (with GC lock held)
255 * in nursery collections
256 * in non-concurrent major collections
257 * in the finishing pause of concurrent major collections (whole list is cleared)
259 * Blocks added to `free_block_lists`:
260 * in the sweeping thread
261 * during nursery collections
262 * from domain clearing (with the world stopped and no sweeping happening)
264 * The only item of those that doesn't require the GC lock is the sweep thread. The sweep
265 * thread only ever adds blocks to the free list, so the ABA problem can't occur.
267 static MSBlockInfo
* volatile *free_block_lists
[MS_BLOCK_TYPE_MAX
];
268 static MonoNativeTlsKey worker_block_free_list_key
;
270 static guint64 stat_major_blocks_alloced
= 0;
271 static guint64 stat_major_blocks_freed
= 0;
272 static guint64 stat_major_blocks_lazy_swept
= 0;
274 static guint64 stat_major_blocks_freed_ideal
= 0;
275 static guint64 stat_major_blocks_freed_less_ideal
= 0;
276 static guint64 stat_major_blocks_freed_individual
= 0;
277 static guint64 stat_major_blocks_alloced_less_ideal
= 0;
279 #ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
280 static guint64 num_major_objects_marked
= 0;
281 #define INC_NUM_MAJOR_OBJECTS_MARKED() (++num_major_objects_marked)
283 #define INC_NUM_MAJOR_OBJECTS_MARKED()
286 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
287 static mono_mutex_t scanned_objects_list_lock
;
288 static SgenPointerQueue scanned_objects_list
;
291 add_scanned_object (void *ptr
)
293 if (!binary_protocol_is_enabled ())
296 mono_os_mutex_lock (&scanned_objects_list_lock
);
297 sgen_pointer_queue_add (&scanned_objects_list
, ptr
);
298 mono_os_mutex_unlock (&scanned_objects_list_lock
);
302 static gboolean
sweep_block (MSBlockInfo
*block
);
305 ms_find_block_obj_size_index (size_t size
)
308 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
);
309 for (i
= 0; i
< num_block_obj_sizes
; ++i
)
310 if (block_obj_sizes
[i
] >= size
)
312 g_error ("no object of size %zd\n", size
);
316 #define FREE_BLOCKS_FROM(lists,p,r) (lists [((p) ? MS_BLOCK_FLAG_PINNED : 0) | ((r) ? MS_BLOCK_FLAG_REFS : 0)])
317 #define FREE_BLOCKS(p,r) (FREE_BLOCKS_FROM (free_block_lists, (p), (r)))
318 #define FREE_BLOCKS_LOCAL(p,r) (FREE_BLOCKS_FROM (((MSBlockInfo***)mono_native_tls_get_value (worker_block_free_list_key)), (p), (r)))
320 #define MS_BLOCK_OBJ_SIZE_INDEX(s) \
321 (((s)+7)>>3 < MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES ? \
322 fast_block_obj_size_indexes [((s)+7)>>3] : \
323 ms_find_block_obj_size_index ((s)))
326 major_alloc_heap (mword nursery_size
, mword nursery_align
)
330 start
= (char *)sgen_alloc_os_memory_aligned (nursery_size
, nursery_align
, (SgenAllocFlags
)(SGEN_ALLOC_HEAP
| SGEN_ALLOC_ACTIVATE
), "nursery", MONO_MEM_ACCOUNT_SGEN_NURSERY
);
332 start
= (char *)sgen_alloc_os_memory (nursery_size
, (SgenAllocFlags
)(SGEN_ALLOC_HEAP
| SGEN_ALLOC_ACTIVATE
), "nursery", MONO_MEM_ACCOUNT_SGEN_NURSERY
);
338 update_heap_boundaries_for_block (MSBlockInfo
*block
)
340 sgen_update_heap_boundaries ((mword
)MS_BLOCK_FOR_BLOCK_INFO (block
), (mword
)MS_BLOCK_FOR_BLOCK_INFO (block
) + ms_block_size
);
347 ms_get_empty_block (void)
351 void *block
, *empty
, *next
;
356 * We try allocating MS_BLOCK_ALLOC_NUM blocks first. If that's
357 * unsuccessful, we halve the number of blocks and try again, until we're at
358 * 1. If that doesn't work, either, we assert.
360 int alloc_num
= MS_BLOCK_ALLOC_NUM
;
362 p
= (char *)sgen_alloc_os_memory_aligned (ms_block_size
* alloc_num
, ms_block_size
,
363 (SgenAllocFlags
)(SGEN_ALLOC_HEAP
| SGEN_ALLOC_ACTIVATE
),
364 alloc_num
== 1 ? "major heap section" : NULL
, MONO_MEM_ACCOUNT_SGEN_MARKSWEEP
);
370 for (i
= 0; i
< alloc_num
; ++i
) {
373 * We do the free list update one after the
374 * other so that other threads can use the new
375 * blocks as quickly as possible.
378 empty
= empty_blocks
;
379 *(void**)block
= empty
;
380 } while (SGEN_CAS_PTR ((gpointer
*)&empty_blocks
, block
, empty
) != empty
);
384 SGEN_ATOMIC_ADD_P (num_empty_blocks
, alloc_num
);
386 stat_major_blocks_alloced
+= alloc_num
;
387 #if SIZEOF_VOID_P != 8
388 if (alloc_num
!= MS_BLOCK_ALLOC_NUM
)
389 stat_major_blocks_alloced_less_ideal
+= alloc_num
;
394 empty
= empty_blocks
;
398 next
= *(void**)block
;
399 } while (SGEN_CAS_PTR (&empty_blocks
, next
, empty
) != empty
);
401 SGEN_ATOMIC_ADD_P (num_empty_blocks
, -1);
403 *(void**)block
= NULL
;
405 g_assert (!((mword
)block
& (ms_block_size
- 1)));
411 * This doesn't actually free a block immediately, but enqueues it into the `empty_blocks`
412 * list, where it will either be freed later on, or reused in nursery collections.
415 ms_free_block (MSBlockInfo
*info
)
418 char *block
= MS_BLOCK_FOR_BLOCK_INFO (info
);
420 sgen_memgov_release_space (ms_block_size
, SPACE_MAJOR
);
421 if (info
->cardtable_mod_union
)
422 sgen_card_table_free_mod_union (info
->cardtable_mod_union
, block
, ms_block_size
);
423 memset (block
, 0, ms_block_size
);
426 empty
= empty_blocks
;
427 *(void**)block
= empty
;
428 } while (SGEN_CAS_PTR (&empty_blocks
, block
, empty
) != empty
);
430 SGEN_ATOMIC_ADD_P (num_empty_blocks
, 1);
432 binary_protocol_block_free (block
, ms_block_size
);
436 sweep_in_progress (void)
438 int state
= sweep_state
;
439 return state
== SWEEP_STATE_SWEEPING
||
440 state
== SWEEP_STATE_SWEEPING_AND_ITERATING
||
441 state
== SWEEP_STATE_COMPACTING
;
444 static inline gboolean
445 block_is_swept_or_marking (MSBlockInfo
*block
)
447 gint32 state
= block
->state
;
448 return state
== BLOCK_STATE_SWEPT
|| state
== BLOCK_STATE_MARKING
;
451 //#define MARKSWEEP_CONSISTENCY_CHECK
453 #ifdef MARKSWEEP_CONSISTENCY_CHECK
455 check_block_free_list (MSBlockInfo
*block
, int size
, gboolean pinned
)
457 SGEN_ASSERT (0, !sweep_in_progress (), "Can't examine allocated blocks during sweep");
458 for (; block
; block
= block
->next_free
) {
459 SGEN_ASSERT (0, block
->state
!= BLOCK_STATE_CHECKING
, "Can't have a block we're checking in a free list.");
460 g_assert (block
->obj_size
== size
);
461 g_assert ((pinned
&& block
->pinned
) || (!pinned
&& !block
->pinned
));
463 /* blocks in the free lists must have at least
465 g_assert (block
->free_list
);
467 /* the block must be in the allocated_blocks array */
468 g_assert (sgen_array_list_find (&allocated_blocks
, BLOCK_TAG (block
)) != (guint32
)-1);
473 check_empty_blocks (void)
477 for (p
= empty_blocks
; p
; p
= *(void**)p
)
479 g_assert (i
== num_empty_blocks
);
483 consistency_check (void)
488 /* check all blocks */
489 FOREACH_BLOCK_NO_LOCK (block
) {
490 int count
= MS_BLOCK_FREE
/ block
->obj_size
;
494 /* count number of free slots */
495 for (i
= 0; i
< count
; ++i
) {
496 void **obj
= (void**) MS_BLOCK_OBJ (block
, i
);
497 if (!MS_OBJ_ALLOCED (obj
, block
))
501 /* check free list */
502 for (free
= block
->free_list
; free
; free
= (void**)*free
) {
503 g_assert (MS_BLOCK_FOR_OBJ (free
) == block
);
506 g_assert (num_free
== 0);
508 /* check all mark words are zero */
509 if (!sgen_concurrent_collection_in_progress () && block_is_swept_or_marking (block
)) {
510 for (i
= 0; i
< MS_NUM_MARK_WORDS
; ++i
)
511 g_assert (block
->mark_words
[i
] == 0);
513 } END_FOREACH_BLOCK_NO_LOCK
;
515 /* check free blocks */
516 for (i
= 0; i
< num_block_obj_sizes
; ++i
) {
518 for (j
= 0; j
< MS_BLOCK_TYPE_MAX
; ++j
)
519 check_block_free_list (free_block_lists
[j
][i
], block_obj_sizes
[i
], j
& MS_BLOCK_FLAG_PINNED
);
522 check_empty_blocks ();
527 add_free_block (MSBlockInfo
* volatile *free_blocks
, int size_index
, MSBlockInfo
*block
)
531 block
->next_free
= old
= free_blocks
[size_index
];
532 } while (SGEN_CAS_PTR ((volatile gpointer
*)&free_blocks
[size_index
], block
, old
) != old
);
535 static void major_finish_sweep_checking (void);
538 ms_alloc_block (int size_index
, gboolean pinned
, gboolean has_references
)
540 int size
= block_obj_sizes
[size_index
];
541 int count
= MS_BLOCK_FREE
/ size
;
543 MSBlockInfo
* volatile * free_blocks
= FREE_BLOCKS (pinned
, has_references
);
547 if (!sgen_memgov_try_alloc_space (ms_block_size
, SPACE_MAJOR
))
550 info
= (MSBlockInfo
*)ms_get_empty_block ();
552 SGEN_ASSERT (9, count
>= 2, "block with %d objects, it must hold at least 2", count
);
554 info
->obj_size
= size
;
555 info
->obj_size_index
= size_index
;
556 info
->pinned
= pinned
;
557 info
->has_references
= has_references
;
558 info
->has_pinned
= pinned
;
560 * Blocks that are to-space are not evacuated from. During an major collection
561 * blocks are allocated for two reasons: evacuating objects from the nursery and
562 * evacuating them from major blocks marked for evacuation. In both cases we don't
563 * want further evacuation. We also don't want to evacuate objects allocated during
564 * the concurrent mark since it would add pointless stress on the finishing pause.
566 info
->is_to_space
= (sgen_get_current_collection_generation () == GENERATION_OLD
) || sgen_concurrent_collection_in_progress ();
567 info
->state
= info
->is_to_space
? BLOCK_STATE_MARKING
: BLOCK_STATE_SWEPT
;
568 SGEN_ASSERT (6, !sweep_in_progress () || info
->state
== BLOCK_STATE_SWEPT
, "How do we add a new block to be swept while sweeping?");
569 info
->cardtable_mod_union
= NULL
;
571 update_heap_boundaries_for_block (info
);
573 binary_protocol_block_alloc (info
, ms_block_size
);
575 /* build free list */
576 obj_start
= MS_BLOCK_FOR_BLOCK_INFO (info
) + MS_BLOCK_SKIP
;
577 info
->free_list
= (void**)obj_start
;
578 /* we're skipping the last one - it must be nulled */
579 for (i
= 0; i
< count
- 1; ++i
) {
580 char *next_obj_start
= obj_start
+ size
;
581 *(void**)obj_start
= next_obj_start
;
582 obj_start
= next_obj_start
;
585 *(void**)obj_start
= NULL
;
587 add_free_block (free_blocks
, size_index
, info
);
589 sgen_array_list_add (&allocated_blocks
, BLOCK_TAG (info
), 0, FALSE
);
591 SGEN_ATOMIC_ADD_P (num_major_sections
, 1);
596 ptr_is_in_major_block (char *ptr
, char **start
, gboolean
*pinned
)
600 FOREACH_BLOCK_NO_LOCK (block
) {
601 if (ptr
>= MS_BLOCK_FOR_BLOCK_INFO (block
) && ptr
<= MS_BLOCK_FOR_BLOCK_INFO (block
) + ms_block_size
) {
602 int count
= MS_BLOCK_FREE
/ block
->obj_size
;
607 for (i
= 0; i
<= count
; ++i
) {
608 if (ptr
>= (char*)MS_BLOCK_OBJ (block
, i
) && ptr
< (char*)MS_BLOCK_OBJ (block
, i
+ 1)) {
610 *start
= (char *)MS_BLOCK_OBJ (block
, i
);
615 *pinned
= block
->pinned
;
618 } END_FOREACH_BLOCK_NO_LOCK
;
623 ptr_is_from_pinned_alloc (char *ptr
)
626 if (ptr_is_in_major_block (ptr
, NULL
, &pinned
))
632 ensure_can_access_block_free_list (MSBlockInfo
*block
)
636 switch (block
->state
) {
637 case BLOCK_STATE_SWEPT
:
638 case BLOCK_STATE_MARKING
:
640 case BLOCK_STATE_CHECKING
:
641 SGEN_ASSERT (0, FALSE
, "How did we get a block that's being checked from a free list?");
643 case BLOCK_STATE_NEED_SWEEPING
:
644 if (sweep_block (block
))
645 ++stat_major_blocks_lazy_swept
;
647 case BLOCK_STATE_SWEEPING
:
648 /* FIXME: do this more elegantly */
652 SGEN_ASSERT (0, FALSE
, "Illegal block state");
659 unlink_slot_from_free_list_uncontested (MSBlockInfo
* volatile *free_blocks
, int size_index
)
661 MSBlockInfo
*block
, *next_free_block
;
662 void *obj
, *next_free_slot
;
665 block
= free_blocks
[size_index
];
666 SGEN_ASSERT (9, block
, "no free block to unlink from free_blocks %p size_index %d", free_blocks
, size_index
);
668 ensure_can_access_block_free_list (block
);
670 obj
= block
->free_list
;
671 SGEN_ASSERT (6, obj
, "block %p in free list had no available object to alloc from", block
);
673 next_free_slot
= *(void**)obj
;
674 if (next_free_slot
) {
675 block
->free_list
= (gpointer
*)next_free_slot
;
679 next_free_block
= block
->next_free
;
680 if (SGEN_CAS_PTR ((volatile gpointer
*)&free_blocks
[size_index
], next_free_block
, block
) != block
)
683 block
->free_list
= NULL
;
684 block
->next_free
= NULL
;
690 alloc_obj (GCVTable vtable
, size_t size
, gboolean pinned
, gboolean has_references
)
692 int size_index
= MS_BLOCK_OBJ_SIZE_INDEX (size
);
693 MSBlockInfo
* volatile * free_blocks
= FREE_BLOCKS (pinned
, has_references
);
696 if (!free_blocks
[size_index
]) {
697 if (G_UNLIKELY (!ms_alloc_block (size_index
, pinned
, has_references
)))
701 obj
= unlink_slot_from_free_list_uncontested (free_blocks
, size_index
);
703 /* FIXME: assumes object layout */
704 *(GCVTable
*)obj
= vtable
;
706 total_allocated_major
+= block_obj_sizes
[size_index
];
708 return (GCObject
*)obj
;
712 major_alloc_object (GCVTable vtable
, size_t size
, gboolean has_references
)
714 return alloc_obj (vtable
, size
, FALSE
, has_references
);
718 * This can only be called by sgen workers. While this is called we assume
719 * that no other thread is accessing the block free lists. The world should
720 * be stopped and the gc thread should be waiting for workers to finish.
723 major_alloc_object_par (GCVTable vtable
, size_t size
, gboolean has_references
)
725 int size_index
= MS_BLOCK_OBJ_SIZE_INDEX (size
);
726 MSBlockInfo
* volatile * free_blocks
= FREE_BLOCKS (FALSE
, has_references
);
727 MSBlockInfo
**free_blocks_local
= FREE_BLOCKS_LOCAL (FALSE
, has_references
);
730 if (free_blocks_local
[size_index
]) {
732 obj
= unlink_slot_from_free_list_uncontested (free_blocks_local
, size_index
);
736 block
= free_blocks
[size_index
];
738 if (G_UNLIKELY (!ms_alloc_block (size_index
, FALSE
, has_references
)))
742 MSBlockInfo
*next_free
= block
->next_free
;
744 * Once a block is removed from the main list, it cannot return on the list until
745 * all the workers are finished and sweep is starting. This means we don't need
746 * to account for ABA problems.
748 if (SGEN_CAS_PTR ((volatile gpointer
*)&free_blocks
[size_index
], next_free
, block
) != block
)
750 block
->next_free
= free_blocks_local
[size_index
];
751 free_blocks_local
[size_index
] = block
;
757 /* FIXME: assumes object layout */
758 *(GCVTable
*)obj
= vtable
;
760 /* FIXME is it worth CAS-ing here */
761 total_allocated_major
+= block_obj_sizes
[size_index
];
763 return (GCObject
*)obj
;
767 * We're not freeing the block if it's empty. We leave that work for
768 * the next major collection.
770 * This is just called from the domain clearing code, which runs in a
771 * single thread and has the GC lock, so we don't need an extra lock.
774 free_object (GCObject
*obj
, size_t size
, gboolean pinned
)
776 MSBlockInfo
*block
= MS_BLOCK_FOR_OBJ (obj
);
778 gboolean in_free_list
;
780 SGEN_ASSERT (9, sweep_state
== SWEEP_STATE_SWEPT
, "Should have waited for sweep to free objects.");
782 ensure_can_access_block_free_list (block
);
783 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
);
784 SGEN_ASSERT (9, MS_OBJ_ALLOCED (obj
, block
), "object %p is already free", obj
);
785 MS_CALC_MARK_BIT (word
, bit
, obj
);
786 SGEN_ASSERT (9, !MS_MARK_BIT (block
, word
, bit
), "object %p has mark bit set", obj
);
788 memset (obj
, 0, size
);
790 in_free_list
= !!block
->free_list
;
791 *(void**)obj
= block
->free_list
;
792 block
->free_list
= (void**)obj
;
795 MSBlockInfo
* volatile *free_blocks
= FREE_BLOCKS (pinned
, block
->has_references
);
796 int size_index
= MS_BLOCK_OBJ_SIZE_INDEX (size
);
797 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
);
798 add_free_block (free_blocks
, size_index
, block
);
803 major_free_non_pinned_object (GCObject
*obj
, size_t size
)
805 free_object (obj
, size
, FALSE
);
808 /* size is a multiple of SGEN_ALLOC_ALIGN */
810 major_alloc_small_pinned_obj (GCVTable vtable
, size_t size
, gboolean has_references
)
814 res
= alloc_obj (vtable
, size
, TRUE
, has_references
);
815 /*If we failed to alloc memory, we better try releasing memory
816 *as pinned alloc is requested by the runtime.
819 sgen_perform_collection (0, GENERATION_OLD
, "pinned alloc failure", TRUE
, TRUE
);
820 res
= alloc_obj (vtable
, size
, TRUE
, has_references
);
822 return (GCObject
*)res
;
826 free_pinned_object (GCObject
*obj
, size_t size
)
828 free_object (obj
, size
, TRUE
);
832 * size is already rounded up and we hold the GC lock.
835 major_alloc_degraded (GCVTable vtable
, size_t size
)
839 obj
= alloc_obj (vtable
, size
, FALSE
, SGEN_VTABLE_HAS_REFERENCES (vtable
));
840 if (G_LIKELY (obj
)) {
841 HEAVY_STAT (++stat_objects_alloced_degraded
);
842 HEAVY_STAT (stat_bytes_alloced_degraded
+= size
);
848 * obj is some object. If it's not in the major heap (i.e. if it's in
849 * the nursery or LOS), return FALSE. Otherwise return whether it's
850 * been marked or copied.
853 major_is_object_live (GCObject
*obj
)
859 if (sgen_ptr_in_nursery (obj
))
862 objsize
= SGEN_ALIGN_UP (sgen_safe_object_get_size (obj
));
865 if (objsize
> SGEN_MAX_SMALL_OBJ_SIZE
)
868 /* now we know it's in a major block */
869 block
= MS_BLOCK_FOR_OBJ (obj
);
870 SGEN_ASSERT (9, !block
->pinned
, "block %p is pinned, BTW why is this bad?", block
);
871 MS_CALC_MARK_BIT (word
, bit
, obj
);
872 return MS_MARK_BIT (block
, word
, bit
) ? TRUE
: FALSE
;
876 major_ptr_is_in_non_pinned_space (char *ptr
, char **start
)
879 if (ptr_is_in_major_block (ptr
, start
, &pinned
))
885 try_set_sweep_state (int new_
, int expected
)
887 int old
= SGEN_CAS (&sweep_state
, new_
, expected
);
888 return old
== expected
;
892 set_sweep_state (int new_
, int expected
)
894 gboolean success
= try_set_sweep_state (new_
, expected
);
895 SGEN_ASSERT (0, success
, "Could not set sweep state.");
898 static gboolean
ensure_block_is_checked_for_sweeping (guint32 block_index
, gboolean wait
, gboolean
*have_checked
);
900 static SgenThreadPoolJob
* volatile sweep_job
;
901 static SgenThreadPoolJob
* volatile sweep_blocks_job
;
904 major_finish_sweep_checking (void)
907 SgenThreadPoolJob
*job
;
910 switch (sweep_state
) {
911 case SWEEP_STATE_SWEPT
:
912 case SWEEP_STATE_NEED_SWEEPING
:
914 case SWEEP_STATE_SWEEPING
:
915 if (try_set_sweep_state (SWEEP_STATE_SWEEPING_AND_ITERATING
, SWEEP_STATE_SWEEPING
))
918 case SWEEP_STATE_SWEEPING_AND_ITERATING
:
919 SGEN_ASSERT (0, FALSE
, "Is there another minor collection running?");
921 case SWEEP_STATE_COMPACTING
:
924 SGEN_ASSERT (0, FALSE
, "Invalid sweep state.");
929 * We're running with the world stopped and the only other thread doing work is the
930 * sweep thread, which doesn't add blocks to the array, so we can safely access
933 for (block_index
= 0; block_index
< allocated_blocks
.next_slot
; ++block_index
)
934 ensure_block_is_checked_for_sweeping (block_index
, FALSE
, NULL
);
936 set_sweep_state (SWEEP_STATE_SWEEPING
, SWEEP_STATE_SWEEPING_AND_ITERATING
);
941 sgen_thread_pool_job_wait (sweep_pool_context
, job
);
942 SGEN_ASSERT (0, !sweep_job
, "Why did the sweep job not null itself?");
943 SGEN_ASSERT (0, sweep_state
== SWEEP_STATE_SWEPT
, "How is the sweep job done but we're not swept?");
947 major_iterate_objects (IterateObjectsFlags flags
, IterateObjectCallbackFunc callback
, void *data
)
949 gboolean sweep
= flags
& ITERATE_OBJECTS_SWEEP
;
950 gboolean non_pinned
= flags
& ITERATE_OBJECTS_NON_PINNED
;
951 gboolean pinned
= flags
& ITERATE_OBJECTS_PINNED
;
954 /* No actual sweeping will take place if we are in the middle of a major collection. */
955 major_finish_sweep_checking ();
956 FOREACH_BLOCK_NO_LOCK (block
) {
957 int count
= MS_BLOCK_FREE
/ block
->obj_size
;
960 if (block
->pinned
&& !pinned
)
962 if (!block
->pinned
&& !non_pinned
)
964 if (sweep
&& lazy_sweep
&& !block_is_swept_or_marking (block
)) {
966 SGEN_ASSERT (6, block
->state
== BLOCK_STATE_SWEPT
, "Block must be swept after sweeping");
969 for (i
= 0; i
< count
; ++i
) {
970 void **obj
= (void**) MS_BLOCK_OBJ (block
, i
);
971 if (MS_OBJ_ALLOCED (obj
, block
))
972 callback ((GCObject
*)obj
, block
->obj_size
, data
);
974 } END_FOREACH_BLOCK_NO_LOCK
;
978 major_is_valid_object (char *object
)
982 FOREACH_BLOCK_NO_LOCK (block
) {
986 if ((MS_BLOCK_FOR_BLOCK_INFO (block
) > object
) || ((MS_BLOCK_FOR_BLOCK_INFO (block
) + ms_block_size
) <= object
))
989 idx
= MS_BLOCK_OBJ_INDEX (object
, block
);
990 obj
= (char*)MS_BLOCK_OBJ (block
, idx
);
993 return MS_OBJ_ALLOCED (obj
, block
);
994 } END_FOREACH_BLOCK_NO_LOCK
;
1001 major_describe_pointer (char *ptr
)
1005 FOREACH_BLOCK_NO_LOCK (block
) {
1013 if ((MS_BLOCK_FOR_BLOCK_INFO (block
) > ptr
) || ((MS_BLOCK_FOR_BLOCK_INFO (block
) + ms_block_size
) <= ptr
))
1016 SGEN_LOG (0, "major-ptr (block %p sz %d pin %d ref %d)\n",
1017 MS_BLOCK_FOR_BLOCK_INFO (block
), block
->obj_size
, block
->pinned
, block
->has_references
);
1019 idx
= MS_BLOCK_OBJ_INDEX (ptr
, block
);
1020 obj
= (char*)MS_BLOCK_OBJ (block
, idx
);
1021 live
= MS_OBJ_ALLOCED (obj
, block
);
1022 vtable
= live
? SGEN_LOAD_VTABLE ((GCObject
*)obj
) : NULL
;
1024 MS_CALC_MARK_BIT (w
, b
, obj
);
1025 marked
= MS_MARK_BIT (block
, w
, b
);
1028 SGEN_LOG (0, "\t(");
1030 SGEN_LOG (0, "object");
1032 SGEN_LOG (0, "dead-object");
1035 SGEN_LOG (0, "interior-ptr offset %zd", ptr
- obj
);
1037 SGEN_LOG (0, "dead-interior-ptr offset %zd", ptr
- obj
);
1040 SGEN_LOG (0, " marked %d)\n", marked
? 1 : 0);
1043 } END_FOREACH_BLOCK_NO_LOCK
;
1049 major_check_scan_starts (void)
1054 major_dump_heap (FILE *heap_dump_file
)
1057 int *slots_available
= (int *)alloca (sizeof (int) * num_block_obj_sizes
);
1058 int *slots_used
= (int *)alloca (sizeof (int) * num_block_obj_sizes
);
1061 for (i
= 0; i
< num_block_obj_sizes
; ++i
)
1062 slots_available
[i
] = slots_used
[i
] = 0;
1064 FOREACH_BLOCK_NO_LOCK (block
) {
1065 int index
= ms_find_block_obj_size_index (block
->obj_size
);
1066 int count
= MS_BLOCK_FREE
/ block
->obj_size
;
1068 slots_available
[index
] += count
;
1069 for (i
= 0; i
< count
; ++i
) {
1070 if (MS_OBJ_ALLOCED (MS_BLOCK_OBJ (block
, i
), block
))
1071 ++slots_used
[index
];
1073 } END_FOREACH_BLOCK_NO_LOCK
;
1075 fprintf (heap_dump_file
, "<occupancies>\n");
1076 for (i
= 0; i
< num_block_obj_sizes
; ++i
) {
1077 fprintf (heap_dump_file
, "<occupancy size=\"%d\" available=\"%d\" used=\"%d\" />\n",
1078 block_obj_sizes
[i
], slots_available
[i
], slots_used
[i
]);
1080 fprintf (heap_dump_file
, "</occupancies>\n");
1082 FOREACH_BLOCK_NO_LOCK (block
) {
1083 int count
= MS_BLOCK_FREE
/ block
->obj_size
;
1087 fprintf (heap_dump_file
, "<section type=\"%s\" size=\"%zu\">\n", "old", (size_t)MS_BLOCK_FREE
);
1089 for (i
= 0; i
<= count
; ++i
) {
1090 if ((i
< count
) && MS_OBJ_ALLOCED (MS_BLOCK_OBJ (block
, i
), block
)) {
1095 sgen_dump_occupied ((char *)MS_BLOCK_OBJ (block
, start
), (char *)MS_BLOCK_OBJ (block
, i
), MS_BLOCK_FOR_BLOCK_INFO (block
));
1101 fprintf (heap_dump_file
, "</section>\n");
1102 } END_FOREACH_BLOCK_NO_LOCK
;
1106 get_cardtable_mod_union_for_block (MSBlockInfo
*block
, gboolean allocate
)
1108 guint8
*mod_union
= block
->cardtable_mod_union
;
1114 mod_union
= sgen_card_table_alloc_mod_union (MS_BLOCK_FOR_BLOCK_INFO (block
), ms_block_size
);
1115 other
= (guint8
*)SGEN_CAS_PTR ((gpointer
*)&block
->cardtable_mod_union
, mod_union
, NULL
);
1117 SGEN_ASSERT (0, block
->cardtable_mod_union
== mod_union
, "Why did CAS not replace?");
1120 sgen_card_table_free_mod_union (mod_union
, MS_BLOCK_FOR_BLOCK_INFO (block
), ms_block_size
);
1124 static inline guint8
*
1125 major_get_cardtable_mod_union_for_reference (char *ptr
)
1127 MSBlockInfo
*block
= MS_BLOCK_FOR_OBJ (ptr
);
1128 size_t offset
= sgen_card_table_get_card_offset (ptr
, (char*)sgen_card_table_align_pointer (MS_BLOCK_FOR_BLOCK_INFO (block
)));
1129 guint8
*mod_union
= get_cardtable_mod_union_for_block (block
, TRUE
);
1130 SGEN_ASSERT (0, mod_union
, "FIXME: optionally allocate the mod union if it's not here and CAS it in.");
1131 return &mod_union
[offset
];
1135 * Mark the mod-union card for `ptr`, which must be a reference within the object `obj`.
1138 mark_mod_union_card (GCObject
*obj
, void **ptr
, GCObject
*value_obj
)
1140 int type
= sgen_obj_get_descriptor (obj
) & DESC_TYPE_MASK
;
1141 if (sgen_safe_object_is_small (obj
, type
)) {
1142 guint8
*card_byte
= major_get_cardtable_mod_union_for_reference ((char*)ptr
);
1143 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?");
1146 sgen_los_mark_mod_union_card (obj
, ptr
);
1148 binary_protocol_mod_union_remset (obj
, ptr
, value_obj
, SGEN_LOAD_VTABLE (value_obj
));
1151 static inline gboolean
1152 major_block_is_evacuating (MSBlockInfo
*block
)
1154 if (evacuate_block_obj_sizes
[block
->obj_size_index
] &&
1155 !block
->has_pinned
&&
1156 !block
->is_to_space
)
1161 #define MS_MARK_OBJECT_AND_ENQUEUE(obj,desc,block,queue) do { \
1162 int __word, __bit; \
1163 MS_CALC_MARK_BIT (__word, __bit, (obj)); \
1164 SGEN_ASSERT (9, MS_OBJ_ALLOCED ((obj), (block)), "object %p not allocated", obj); \
1165 if (!MS_MARK_BIT ((block), __word, __bit)) { \
1166 MS_SET_MARK_BIT ((block), __word, __bit); \
1167 if (sgen_gc_descr_has_references (desc)) \
1168 GRAY_OBJECT_ENQUEUE_SERIAL ((queue), (obj), (desc)); \
1169 binary_protocol_mark ((obj), (gpointer)SGEN_LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((obj))); \
1170 INC_NUM_MAJOR_OBJECTS_MARKED (); \
1173 #define MS_MARK_OBJECT_AND_ENQUEUE_PAR(obj,desc,block,queue) do { \
1174 int __word, __bit; \
1176 MS_CALC_MARK_BIT (__word, __bit, (obj)); \
1177 SGEN_ASSERT (9, MS_OBJ_ALLOCED ((obj), (block)), "object %p not allocated", obj); \
1178 MS_SET_MARK_BIT_PAR ((block), __word, __bit, first); \
1180 if (sgen_gc_descr_has_references (desc)) \
1181 GRAY_OBJECT_ENQUEUE_PARALLEL ((queue), (obj), (desc)); \
1182 binary_protocol_mark ((obj), (gpointer)SGEN_LOAD_VTABLE ((obj)), sgen_safe_object_get_size ((obj))); \
1183 INC_NUM_MAJOR_OBJECTS_MARKED (); \
1190 pin_major_object (GCObject
*obj
, SgenGrayQueue
*queue
)
1194 if (concurrent_mark
)
1195 g_assert_not_reached ();
1197 block
= MS_BLOCK_FOR_OBJ (obj
);
1198 block
->has_pinned
= TRUE
;
1199 MS_MARK_OBJECT_AND_ENQUEUE (obj
, sgen_obj_get_descriptor (obj
), block
, queue
);
1202 #define COPY_OR_MARK_PARALLEL
1203 #include "sgen-major-copy-object.h"
1206 major_get_and_reset_num_major_objects_marked (void)
1208 #ifdef SGEN_COUNT_NUMBER_OF_MAJOR_OBJECTS_MARKED
1209 long long num
= num_major_objects_marked
;
1210 num_major_objects_marked
= 0;
1217 #define PREFETCH_CARDS 1 /* BOOL FASTENABLE */
1219 #undef PREFETCH_CARDS
1222 /* gcc 4.2.1 from xcode4 crashes on sgen_card_table_get_card_address () when this is enabled */
1223 #if defined(PLATFORM_MACOSX)
1224 #if MONO_GNUC_VERSION <= 40300
1225 #undef PREFETCH_CARDS
1229 #ifdef HEAVY_STATISTICS
1230 static guint64 stat_optimized_copy
;
1231 static guint64 stat_optimized_copy_nursery
;
1232 static guint64 stat_optimized_copy_nursery_forwarded
;
1233 static guint64 stat_optimized_copy_nursery_pinned
;
1234 static guint64 stat_optimized_copy_major
;
1235 static guint64 stat_optimized_copy_major_small_fast
;
1236 static guint64 stat_optimized_copy_major_small_slow
;
1237 static guint64 stat_optimized_copy_major_large
;
1238 static guint64 stat_optimized_copy_major_forwarded
;
1239 static guint64 stat_optimized_copy_major_small_evacuate
;
1240 static guint64 stat_optimized_major_scan
;
1241 static guint64 stat_optimized_major_scan_no_refs
;
1243 static guint64 stat_drain_prefetch_fills
;
1244 static guint64 stat_drain_prefetch_fill_failures
;
1245 static guint64 stat_drain_loops
;
1248 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_no_evacuation
1249 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_no_evacuation
1250 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_no_evacuation
1251 #include "sgen-marksweep-drain-gray-stack.h"
1253 #define COPY_OR_MARK_PARALLEL
1254 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_par_no_evacuation
1255 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_par_no_evacuation
1256 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_par_no_evacuation
1257 #include "sgen-marksweep-drain-gray-stack.h"
1259 #define COPY_OR_MARK_WITH_EVACUATION
1260 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_with_evacuation
1261 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_with_evacuation
1262 #define SCAN_VTYPE_FUNCTION_NAME major_scan_vtype_with_evacuation
1263 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_with_evacuation
1264 #define SCAN_PTR_FIELD_FUNCTION_NAME major_scan_ptr_field_with_evacuation
1265 #include "sgen-marksweep-drain-gray-stack.h"
1267 #define COPY_OR_MARK_PARALLEL
1268 #define COPY_OR_MARK_WITH_EVACUATION
1269 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_par_with_evacuation
1270 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_par_with_evacuation
1271 #define SCAN_VTYPE_FUNCTION_NAME major_scan_vtype_par_with_evacuation
1272 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_par_with_evacuation
1273 #define SCAN_PTR_FIELD_FUNCTION_NAME major_scan_ptr_field_par_with_evacuation
1274 #include "sgen-marksweep-drain-gray-stack.h"
1276 #define COPY_OR_MARK_CONCURRENT
1277 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_concurrent_no_evacuation
1278 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_concurrent_no_evacuation
1279 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_concurrent_no_evacuation
1280 #include "sgen-marksweep-drain-gray-stack.h"
1282 #define COPY_OR_MARK_PARALLEL
1283 #define COPY_OR_MARK_CONCURRENT
1284 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_concurrent_par_no_evacuation
1285 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_concurrent_par_no_evacuation
1286 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_concurrent_par_no_evacuation
1287 #include "sgen-marksweep-drain-gray-stack.h"
1289 #define COPY_OR_MARK_CONCURRENT_WITH_EVACUATION
1290 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_concurrent_with_evacuation
1291 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_concurrent_with_evacuation
1292 #define SCAN_VTYPE_FUNCTION_NAME major_scan_vtype_concurrent_with_evacuation
1293 #define SCAN_PTR_FIELD_FUNCTION_NAME major_scan_ptr_field_concurrent_with_evacuation
1294 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_concurrent_with_evacuation
1295 #include "sgen-marksweep-drain-gray-stack.h"
1297 #define COPY_OR_MARK_PARALLEL
1298 #define COPY_OR_MARK_CONCURRENT_WITH_EVACUATION
1299 #define COPY_OR_MARK_FUNCTION_NAME major_copy_or_mark_object_concurrent_par_with_evacuation
1300 #define SCAN_OBJECT_FUNCTION_NAME major_scan_object_concurrent_par_with_evacuation
1301 #define SCAN_VTYPE_FUNCTION_NAME major_scan_vtype_concurrent_par_with_evacuation
1302 #define SCAN_PTR_FIELD_FUNCTION_NAME major_scan_ptr_field_concurrent_par_with_evacuation
1303 #define DRAIN_GRAY_STACK_FUNCTION_NAME drain_gray_stack_concurrent_par_with_evacuation
1304 #include "sgen-marksweep-drain-gray-stack.h"
1306 static inline gboolean
1307 major_is_evacuating (void)
1310 for (i
= 0; i
< num_block_obj_sizes
; ++i
) {
1311 if (evacuate_block_obj_sizes
[i
]) {
1320 drain_gray_stack (SgenGrayQueue
*queue
)
1322 if (major_is_evacuating ())
1323 return drain_gray_stack_with_evacuation (queue
);
1325 return drain_gray_stack_no_evacuation (queue
);
1329 drain_gray_stack_par (SgenGrayQueue
*queue
)
1331 if (major_is_evacuating ())
1332 return drain_gray_stack_par_with_evacuation (queue
);
1334 return drain_gray_stack_par_no_evacuation (queue
);
1338 drain_gray_stack_concurrent (SgenGrayQueue
*queue
)
1340 if (major_is_evacuating ())
1341 return drain_gray_stack_concurrent_with_evacuation (queue
);
1343 return drain_gray_stack_concurrent_no_evacuation (queue
);
1347 drain_gray_stack_concurrent_par (SgenGrayQueue
*queue
)
1349 if (major_is_evacuating ())
1350 return drain_gray_stack_concurrent_par_with_evacuation (queue
);
1352 return drain_gray_stack_concurrent_par_no_evacuation (queue
);
1356 major_copy_or_mark_object_canonical (GCObject
**ptr
, SgenGrayQueue
*queue
)
1358 major_copy_or_mark_object_with_evacuation (ptr
, *ptr
, queue
);
1362 major_copy_or_mark_object_concurrent_canonical (GCObject
**ptr
, SgenGrayQueue
*queue
)
1364 major_copy_or_mark_object_concurrent_with_evacuation (ptr
, *ptr
, queue
);
1368 major_copy_or_mark_object_concurrent_par_canonical (GCObject
**ptr
, SgenGrayQueue
*queue
)
1370 major_copy_or_mark_object_concurrent_par_with_evacuation (ptr
, *ptr
, queue
);
1374 major_copy_or_mark_object_concurrent_finish_canonical (GCObject
**ptr
, SgenGrayQueue
*queue
)
1376 major_copy_or_mark_object_with_evacuation (ptr
, *ptr
, queue
);
1380 major_copy_or_mark_object_concurrent_par_finish_canonical (GCObject
**ptr
, SgenGrayQueue
*queue
)
1382 major_copy_or_mark_object_par_with_evacuation (ptr
, *ptr
, queue
);
1386 mark_pinned_objects_in_block (MSBlockInfo
*block
, size_t first_entry
, size_t last_entry
, SgenGrayQueue
*queue
)
1388 void **entry
, **end
;
1389 int last_index
= -1;
1391 if (first_entry
== last_entry
)
1394 entry
= sgen_pinning_get_entry (first_entry
);
1395 end
= sgen_pinning_get_entry (last_entry
);
1397 for (; entry
< end
; ++entry
) {
1398 int index
= MS_BLOCK_OBJ_INDEX (*entry
, block
);
1400 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
));
1401 if (index
== last_index
)
1403 obj
= MS_BLOCK_OBJ (block
, index
);
1404 if (!MS_OBJ_ALLOCED (obj
, block
))
1406 MS_MARK_OBJECT_AND_ENQUEUE (obj
, sgen_obj_get_descriptor (obj
), block
, queue
);
1407 sgen_pin_stats_register_object (obj
, GENERATION_OLD
);
1412 * There might have been potential pinning "pointers" into this block, but none of
1413 * them pointed to occupied slots, in which case we don't have to pin the block.
1415 if (last_index
>= 0)
1416 block
->has_pinned
= TRUE
;
1420 sweep_block_for_size (MSBlockInfo
*block
, int count
, int obj_size
)
1423 void *obj
= MS_BLOCK_OBJ_FOR_SIZE (block
, 0, obj_size
);
1425 for (obj_index
= 0; obj_index
< count
; ++obj_index
, obj
= (void*)((mword
)obj
+ obj_size
)) {
1428 MS_CALC_MARK_BIT (word
, bit
, obj
);
1429 if (MS_MARK_BIT (block
, word
, bit
)) {
1430 SGEN_ASSERT (9, MS_OBJ_ALLOCED (obj
, block
), "object %p not allocated", obj
);
1432 /* an unmarked object */
1433 if (MS_OBJ_ALLOCED (obj
, block
)) {
1435 * FIXME: Merge consecutive
1436 * slots for lower reporting
1437 * overhead. Maybe memset
1438 * will also benefit?
1440 binary_protocol_empty (obj
, obj_size
);
1441 memset (obj
, 0, obj_size
);
1443 *(void**)obj
= block
->free_list
;
1444 block
->free_list
= (void **)obj
;
1449 static inline gboolean
1450 try_set_block_state (MSBlockInfo
*block
, gint32 new_state
, gint32 expected_state
)
1452 gint32 old_state
= SGEN_CAS (&block
->state
, new_state
, expected_state
);
1453 gboolean success
= old_state
== expected_state
;
1455 binary_protocol_block_set_state (block
, ms_block_size
, old_state
, new_state
);
1460 set_block_state (MSBlockInfo
*block
, gint32 new_state
, gint32 expected_state
)
1462 SGEN_ASSERT (6, block
->state
== expected_state
, "Block state incorrect before set");
1463 block
->state
= new_state
;
1464 binary_protocol_block_set_state (block
, ms_block_size
, expected_state
, new_state
);
1468 * If `block` needs sweeping, sweep it and return TRUE. Otherwise return FALSE.
1470 * Sweeping means iterating through the block's slots and building the free-list from the
1471 * unmarked ones. They will also be zeroed. The mark bits will be reset.
1474 sweep_block (MSBlockInfo
*block
)
1477 void *reversed
= NULL
;
1480 switch (block
->state
) {
1481 case BLOCK_STATE_SWEPT
:
1483 case BLOCK_STATE_MARKING
:
1484 case BLOCK_STATE_CHECKING
:
1485 SGEN_ASSERT (0, FALSE
, "How did we get to sweep a block that's being marked or being checked?");
1487 case BLOCK_STATE_SWEEPING
:
1488 /* FIXME: Do this more elegantly */
1491 case BLOCK_STATE_NEED_SWEEPING
:
1492 if (!try_set_block_state (block
, BLOCK_STATE_SWEEPING
, BLOCK_STATE_NEED_SWEEPING
))
1496 SGEN_ASSERT (0, FALSE
, "Illegal block state");
1499 SGEN_ASSERT (6, block
->state
== BLOCK_STATE_SWEEPING
, "How did we get here without setting state to sweeping?");
1501 count
= MS_BLOCK_FREE
/ block
->obj_size
;
1503 block
->free_list
= NULL
;
1505 /* Use inline instances specialized to constant sizes, this allows the compiler to replace the memset calls with inline code */
1506 // FIXME: Add more sizes
1507 switch (block
->obj_size
) {
1509 sweep_block_for_size (block
, count
, 16);
1512 sweep_block_for_size (block
, count
, block
->obj_size
);
1516 /* reset mark bits */
1517 memset (block
->mark_words
, 0, sizeof (guint32
) * MS_NUM_MARK_WORDS
);
1519 /* Reverse free list so that it's in address order */
1521 while (block
->free_list
) {
1522 void *next
= *(void**)block
->free_list
;
1523 *(void**)block
->free_list
= reversed
;
1524 reversed
= block
->free_list
;
1525 block
->free_list
= (void **)next
;
1527 block
->free_list
= (void **)reversed
;
1529 mono_memory_write_barrier ();
1531 set_block_state (block
, BLOCK_STATE_SWEPT
, BLOCK_STATE_SWEEPING
);
1542 if (sizeof (mword
) == 8)
1543 count
+= __builtin_popcountll (d
);
1545 count
+= __builtin_popcount (d
);
1555 /* statistics for evacuation */
1556 static size_t *sweep_slots_available
;
1557 static size_t *sweep_slots_used
;
1558 static size_t *sweep_num_blocks
;
1560 static volatile size_t num_major_sections_before_sweep
;
1561 static volatile size_t num_major_sections_freed_in_sweep
;
1564 sgen_worker_clear_free_block_lists (WorkerData
*worker
)
1568 if (!worker
->free_block_lists
)
1571 for (i
= 0; i
< MS_BLOCK_TYPE_MAX
; i
++) {
1572 for (j
= 0; j
< num_block_obj_sizes
; j
++) {
1573 ((MSBlockInfo
***) worker
->free_block_lists
) [i
][j
] = NULL
;
1579 sgen_worker_clear_free_block_lists_evac (WorkerData
*worker
)
1583 if (!worker
->free_block_lists
)
1586 for (i
= 0; i
< MS_BLOCK_TYPE_MAX
; i
++) {
1587 for (j
= 0; j
< num_block_obj_sizes
; j
++) {
1588 if (((MSBlockInfo
***) worker
->free_block_lists
) [i
][j
])
1589 SGEN_ASSERT (0, !((MSBlockInfo
***) worker
->free_block_lists
) [i
][j
]->next_free
, "Why do we have linked free blocks on the workers");
1591 if (evacuate_block_obj_sizes
[j
])
1592 ((MSBlockInfo
***) worker
->free_block_lists
) [i
][j
] = NULL
;
1602 for (i
= 0; i
< num_block_obj_sizes
; ++i
)
1603 sweep_slots_available
[i
] = sweep_slots_used
[i
] = sweep_num_blocks
[i
] = 0;
1605 /* clear all the free lists */
1606 for (i
= 0; i
< MS_BLOCK_TYPE_MAX
; ++i
) {
1607 MSBlockInfo
* volatile *free_blocks
= free_block_lists
[i
];
1609 for (j
= 0; j
< num_block_obj_sizes
; ++j
)
1610 free_blocks
[j
] = NULL
;
1613 sgen_workers_foreach (GENERATION_NURSERY
, sgen_worker_clear_free_block_lists
);
1614 sgen_workers_foreach (GENERATION_OLD
, sgen_worker_clear_free_block_lists
);
1616 compact_blocks
= TRUE
;
1619 static void sweep_finish (void);
1622 * If `wait` is TRUE and the block is currently being checked, this function will wait until
1623 * the checking has finished.
1625 * Returns whether the block is still there. If `wait` is FALSE, the return value will not
1626 * be correct, i.e. must not be used.
1629 ensure_block_is_checked_for_sweeping (guint32 block_index
, gboolean wait
, gboolean
*have_checked
)
1632 gboolean have_live
= FALSE
;
1633 gboolean have_free
= FALSE
;
1639 volatile gpointer
*block_slot
= sgen_array_list_get_slot (&allocated_blocks
, block_index
);
1641 SGEN_ASSERT (6, sweep_in_progress (), "Why do we call this function if there's no sweep in progress?");
1644 *have_checked
= FALSE
;
1647 tagged_block
= *(void * volatile *)block_slot
;
1651 if (BLOCK_IS_TAGGED_CHECKING (tagged_block
)) {
1654 /* FIXME: do this more elegantly */
1659 if (SGEN_CAS_PTR (block_slot
, BLOCK_TAG_CHECKING (tagged_block
), tagged_block
) != tagged_block
)
1662 block
= BLOCK_UNTAG (tagged_block
);
1663 block_state
= block
->state
;
1665 if (!sweep_in_progress ()) {
1666 SGEN_ASSERT (6, block_state
!= BLOCK_STATE_SWEEPING
&& block_state
!= BLOCK_STATE_CHECKING
, "Invalid block state.");
1668 SGEN_ASSERT (6, block_state
!= BLOCK_STATE_NEED_SWEEPING
, "Invalid block state.");
1671 switch (block_state
) {
1672 case BLOCK_STATE_SWEPT
:
1673 case BLOCK_STATE_NEED_SWEEPING
:
1674 case BLOCK_STATE_SWEEPING
:
1676 case BLOCK_STATE_MARKING
:
1678 case BLOCK_STATE_CHECKING
:
1679 SGEN_ASSERT (0, FALSE
, "We set the CHECKING bit - how can the stage be CHECKING?");
1682 SGEN_ASSERT (0, FALSE
, "Illegal block state");
1686 SGEN_ASSERT (6, block
->state
== BLOCK_STATE_MARKING
, "When we sweep all blocks must start out marking.");
1687 set_block_state (block
, BLOCK_STATE_CHECKING
, BLOCK_STATE_MARKING
);
1690 *have_checked
= TRUE
;
1692 block
->has_pinned
= block
->pinned
;
1694 block
->is_to_space
= FALSE
;
1696 count
= MS_BLOCK_FREE
/ block
->obj_size
;
1698 if (block
->cardtable_mod_union
)
1699 memset (block
->cardtable_mod_union
, 0, CARDS_PER_BLOCK
);
1701 /* Count marked objects in the block */
1702 for (i
= 0; i
< MS_NUM_MARK_WORDS
; ++i
)
1703 nused
+= bitcount (block
->mark_words
[i
]);
1705 block
->nused
= nused
;
1712 int obj_size_index
= block
->obj_size_index
;
1713 gboolean has_pinned
= block
->has_pinned
;
1715 set_block_state (block
, BLOCK_STATE_NEED_SWEEPING
, BLOCK_STATE_CHECKING
);
1718 * FIXME: Go straight to SWEPT if there are no free slots. We need
1719 * to set the free slot list to NULL, though, and maybe update some
1723 sweep_block (block
);
1726 ++sweep_num_blocks
[obj_size_index
];
1727 sweep_slots_used
[obj_size_index
] += nused
;
1728 sweep_slots_available
[obj_size_index
] += count
;
1732 * If there are free slots in the block, add
1733 * the block to the corresponding free list.
1736 MSBlockInfo
* volatile *free_blocks
= FREE_BLOCKS (block
->pinned
, block
->has_references
);
1739 SGEN_ASSERT (6, block
->free_list
, "How do we not have a free list when there are free slots?");
1741 add_free_block (free_blocks
, obj_size_index
, block
);
1744 /* FIXME: Do we need the heap boundaries while we do nursery collections? */
1745 update_heap_boundaries_for_block (block
);
1748 * Blocks without live objects are removed from the
1749 * block list and freed.
1751 SGEN_ASSERT (6, block_index
< allocated_blocks
.next_slot
, "How did the number of blocks shrink?");
1752 SGEN_ASSERT (6, *block_slot
== BLOCK_TAG_CHECKING (tagged_block
), "How did the block move?");
1754 binary_protocol_empty (MS_BLOCK_OBJ (block
, 0), (char*)MS_BLOCK_OBJ (block
, count
) - (char*)MS_BLOCK_OBJ (block
, 0));
1755 ms_free_block (block
);
1757 SGEN_ATOMIC_ADD_P (num_major_sections
, -1);
1758 SGEN_ATOMIC_ADD_P (num_major_sections_freed_in_sweep
, 1);
1760 tagged_block
= NULL
;
1765 * Once the block is written back without the checking bit other threads are
1766 * free to access it. Make sure the block state is visible before we write it
1769 mono_memory_write_barrier ();
1770 *block_slot
= tagged_block
;
1771 return !!tagged_block
;
1775 sweep_blocks_job_func (void *thread_data_untyped
, SgenThreadPoolJob
*job
)
1777 volatile gpointer
*slot
;
1780 SGEN_ARRAY_LIST_FOREACH_SLOT (&allocated_blocks
, slot
) {
1781 bl
= BLOCK_UNTAG (*slot
);
1784 } SGEN_ARRAY_LIST_END_FOREACH_SLOT
;
1786 mono_memory_write_barrier ();
1788 sweep_blocks_job
= NULL
;
1792 sweep_job_func (void *thread_data_untyped
, SgenThreadPoolJob
*job
)
1794 guint32 block_index
;
1795 guint32 num_blocks
= num_major_sections_before_sweep
;
1797 SGEN_ASSERT (0, sweep_in_progress (), "Sweep thread called with wrong state");
1798 SGEN_ASSERT (0, num_blocks
<= allocated_blocks
.next_slot
, "How did we lose blocks?");
1801 * We traverse the block array from high to low. Nursery collections will have to
1802 * cooperate with the sweep thread to finish sweeping, and they will traverse from
1803 * low to high, to avoid constantly colliding on the same blocks.
1805 for (block_index
= allocated_blocks
.next_slot
; block_index
-- > 0;) {
1806 ensure_block_is_checked_for_sweeping (block_index
, TRUE
, NULL
);
1809 while (!try_set_sweep_state (SWEEP_STATE_COMPACTING
, SWEEP_STATE_SWEEPING
)) {
1811 * The main GC thread is currently iterating over the block array to help us
1812 * finish the sweep. We have already finished, but we don't want to mess up
1813 * that iteration, so we just wait for it.
1818 if (SGEN_MAX_ASSERT_LEVEL
>= 6) {
1819 for (block_index
= num_blocks
; block_index
< allocated_blocks
.next_slot
; ++block_index
) {
1820 MSBlockInfo
*block
= BLOCK_UNTAG (*sgen_array_list_get_slot (&allocated_blocks
, block_index
));
1821 SGEN_ASSERT (6, block
&& block
->state
== BLOCK_STATE_SWEPT
, "How did a new block to be swept get added while swept?");
1826 * Concurrently sweep all the blocks to reduce workload during minor
1827 * pauses where we need certain blocks to be swept. At the start of
1828 * the next major we need all blocks to be swept anyway.
1830 if (concurrent_sweep
&& lazy_sweep
) {
1831 sweep_blocks_job
= sgen_thread_pool_job_alloc ("sweep_blocks", sweep_blocks_job_func
, sizeof (SgenThreadPoolJob
));
1832 sgen_thread_pool_job_enqueue (sweep_pool_context
, sweep_blocks_job
);
1843 mword used_slots_size
= 0;
1846 for (i
= 0; i
< num_block_obj_sizes
; ++i
) {
1847 float usage
= (float)sweep_slots_used
[i
] / (float)sweep_slots_available
[i
];
1848 if (sweep_num_blocks
[i
] > 5 && usage
< evacuation_threshold
) {
1849 evacuate_block_obj_sizes
[i
] = TRUE
;
1851 g_print ("slot size %d - %d of %d used\n",
1852 block_obj_sizes [i], slots_used [i], slots_available [i]);
1855 evacuate_block_obj_sizes
[i
] = FALSE
;
1858 used_slots_size
+= sweep_slots_used
[i
] * block_obj_sizes
[i
];
1861 sgen_memgov_major_post_sweep (used_slots_size
);
1863 set_sweep_state (SWEEP_STATE_SWEPT
, SWEEP_STATE_COMPACTING
);
1864 if (concurrent_sweep
)
1865 binary_protocol_concurrent_sweep_end (sgen_timestamp ());
1871 set_sweep_state (SWEEP_STATE_SWEEPING
, SWEEP_STATE_NEED_SWEEPING
);
1875 num_major_sections_before_sweep
= num_major_sections
;
1876 num_major_sections_freed_in_sweep
= 0;
1878 SGEN_ASSERT (0, !sweep_job
, "We haven't finished the last sweep?");
1879 if (concurrent_sweep
) {
1880 sweep_job
= sgen_thread_pool_job_alloc ("sweep", sweep_job_func
, sizeof (SgenThreadPoolJob
));
1881 sgen_thread_pool_job_enqueue (sweep_pool_context
, sweep_job
);
1883 sweep_job_func (NULL
, NULL
);
1888 major_have_swept (void)
1890 return sweep_state
== SWEEP_STATE_SWEPT
;
1893 static int count_pinned_ref
;
1894 static int count_pinned_nonref
;
1895 static int count_nonpinned_ref
;
1896 static int count_nonpinned_nonref
;
1899 count_nonpinned_callback (GCObject
*obj
, size_t size
, void *data
)
1901 GCVTable vtable
= SGEN_LOAD_VTABLE (obj
);
1903 if (SGEN_VTABLE_HAS_REFERENCES (vtable
))
1904 ++count_nonpinned_ref
;
1906 ++count_nonpinned_nonref
;
1910 count_pinned_callback (GCObject
*obj
, size_t size
, void *data
)
1912 GCVTable vtable
= SGEN_LOAD_VTABLE (obj
);
1914 if (SGEN_VTABLE_HAS_REFERENCES (vtable
))
1917 ++count_pinned_nonref
;
1920 static G_GNUC_UNUSED
void
1921 count_ref_nonref_objs (void)
1925 count_pinned_ref
= 0;
1926 count_pinned_nonref
= 0;
1927 count_nonpinned_ref
= 0;
1928 count_nonpinned_nonref
= 0;
1930 major_iterate_objects (ITERATE_OBJECTS_SWEEP_NON_PINNED
, count_nonpinned_callback
, NULL
);
1931 major_iterate_objects (ITERATE_OBJECTS_SWEEP_PINNED
, count_pinned_callback
, NULL
);
1933 total
= count_pinned_nonref
+ count_nonpinned_nonref
+ count_pinned_ref
+ count_nonpinned_ref
;
1935 g_print ("ref: %d pinned %d non-pinned non-ref: %d pinned %d non-pinned -- %.1f\n",
1936 count_pinned_ref
, count_nonpinned_ref
,
1937 count_pinned_nonref
, count_nonpinned_nonref
,
1938 (count_pinned_nonref
+ count_nonpinned_nonref
) * 100.0 / total
);
1942 ms_calculate_block_obj_sizes (double factor
, int *arr
)
1949 * Have every possible slot size starting with the minimal
1950 * object size up to and including four times that size. Then
1951 * proceed by increasing geometrically with the given factor.
1954 for (int size
= SGEN_CLIENT_MINIMUM_OBJECT_SIZE
; size
<= 4 * SGEN_CLIENT_MINIMUM_OBJECT_SIZE
; size
+= SGEN_ALLOC_ALIGN
) {
1956 arr
[num_sizes
] = size
;
1960 target_size
= (double)last_size
;
1963 int target_count
= (int)floor (MS_BLOCK_FREE
/ target_size
);
1964 int size
= MIN ((MS_BLOCK_FREE
/ target_count
) & ~(SGEN_ALLOC_ALIGN
- 1), SGEN_MAX_SMALL_OBJ_SIZE
);
1966 if (size
!= last_size
) {
1968 arr
[num_sizes
] = size
;
1973 target_size
*= factor
;
1974 } while (last_size
< SGEN_MAX_SMALL_OBJ_SIZE
);
1979 /* only valid during minor collections */
1980 static mword old_num_major_sections
;
1983 major_start_nursery_collection (void)
1985 #ifdef MARKSWEEP_CONSISTENCY_CHECK
1986 consistency_check ();
1989 old_num_major_sections
= num_major_sections
;
1991 /* Compact the block list if it hasn't been compacted in a while and nobody is using it */
1992 if (compact_blocks
&& !sweep_in_progress () && !sweep_blocks_job
&& !sgen_concurrent_collection_in_progress ()) {
1994 * We support null elements in the array but do regular compaction to avoid
1995 * excessive traversal of the array and to facilitate splitting into well
1996 * balanced sections for parallel modes. We compact as soon as possible after
1999 sgen_array_list_remove_nulls (&allocated_blocks
);
2000 compact_blocks
= FALSE
;
2005 major_finish_nursery_collection (void)
2007 #ifdef MARKSWEEP_CONSISTENCY_CHECK
2008 consistency_check ();
2013 block_usage_comparer (const void *bl1
, const void *bl2
)
2015 const gint16 nused1
= (*(MSBlockInfo
**)bl1
)->nused
;
2016 const gint16 nused2
= (*(MSBlockInfo
**)bl2
)->nused
;
2018 return nused2
- nused1
;
2022 sgen_evacuation_freelist_blocks (MSBlockInfo
* volatile *block_list
, int size_index
)
2024 MSBlockInfo
**evacuated_blocks
;
2025 size_t index
= 0, count
, num_blocks
= 0, num_used
= 0;
2027 MSBlockInfo
* volatile *prev
;
2029 for (info
= *block_list
; info
!= NULL
; info
= info
->next_free
) {
2031 num_used
+= info
->nused
;
2035 * We have a set of blocks in the freelist which will be evacuated. Instead
2036 * of evacuating all of the blocks into new ones, we traverse the freelist
2037 * sorting it by the number of occupied slots, evacuating the objects from
2038 * blocks with fewer used slots into fuller blocks.
2040 * The number of used slots is set at the end of the previous sweep. Since
2041 * we sequentially unlink slots from blocks, except for the head of the
2042 * freelist, for blocks on the freelist, the number of used slots is the same
2043 * as at the end of the previous sweep.
2045 evacuated_blocks
= (MSBlockInfo
**)sgen_alloc_internal_dynamic (sizeof (MSBlockInfo
*) * num_blocks
, INTERNAL_MEM_TEMPORARY
, TRUE
);
2047 for (info
= *block_list
; info
!= NULL
; info
= info
->next_free
) {
2048 evacuated_blocks
[index
++] = info
;
2051 SGEN_ASSERT (0, num_blocks
== index
, "Why did the freelist change ?");
2053 sgen_qsort (evacuated_blocks
, num_blocks
, sizeof (gpointer
), block_usage_comparer
);
2056 * Form a new freelist with the fullest blocks. These blocks will also be
2057 * marked as to_space so we don't evacuate from them.
2059 count
= MS_BLOCK_FREE
/ block_obj_sizes
[size_index
];
2061 for (index
= 0; index
< (num_used
+ count
- 1) / count
; index
++) {
2062 SGEN_ASSERT (0, index
< num_blocks
, "Why do we need more blocks for compaction than we already had ?");
2063 info
= evacuated_blocks
[index
];
2064 info
->is_to_space
= TRUE
;
2066 prev
= &info
->next_free
;
2070 sgen_free_internal_dynamic (evacuated_blocks
, sizeof (MSBlockInfo
*) * num_blocks
, INTERNAL_MEM_TEMPORARY
);
2074 major_start_major_collection (void)
2079 major_finish_sweep_checking ();
2082 * Clear the free lists for block sizes where we do evacuation. For those block
2083 * sizes we will have to allocate new blocks.
2085 for (i
= 0; i
< num_block_obj_sizes
; ++i
) {
2086 if (!evacuate_block_obj_sizes
[i
])
2089 binary_protocol_evacuating_blocks (block_obj_sizes
[i
]);
2091 sgen_evacuation_freelist_blocks (&free_block_lists
[0][i
], i
);
2092 sgen_evacuation_freelist_blocks (&free_block_lists
[MS_BLOCK_FLAG_REFS
][i
], i
);
2095 /* We expect workers to have very few blocks on the freelist, just evacuate them */
2096 sgen_workers_foreach (GENERATION_NURSERY
, sgen_worker_clear_free_block_lists_evac
);
2097 sgen_workers_foreach (GENERATION_OLD
, sgen_worker_clear_free_block_lists_evac
);
2099 if (lazy_sweep
&& concurrent_sweep
) {
2101 * sweep_blocks_job is created before sweep_finish, which we wait for above
2102 * (major_finish_sweep_checking). After the end of sweep, if we don't have
2103 * sweep_blocks_job set, it means that it has already been run.
2105 SgenThreadPoolJob
*job
= sweep_blocks_job
;
2107 sgen_thread_pool_job_wait (sweep_pool_context
, job
);
2110 if (lazy_sweep
&& !concurrent_sweep
)
2111 binary_protocol_sweep_begin (GENERATION_OLD
, TRUE
);
2112 /* Sweep all unswept blocks and set them to MARKING */
2113 FOREACH_BLOCK_NO_LOCK (block
) {
2114 if (lazy_sweep
&& !concurrent_sweep
)
2115 sweep_block (block
);
2116 SGEN_ASSERT (0, block
->state
== BLOCK_STATE_SWEPT
, "All blocks must be swept when we're pinning.");
2117 set_block_state (block
, BLOCK_STATE_MARKING
, BLOCK_STATE_SWEPT
);
2119 * Swept blocks that have a null free_list are full. Evacuation is not
2120 * effective on these blocks since we expect them to have high usage anyway,
2121 * given that the survival rate for majors is relatively high.
2123 if (evacuate_block_obj_sizes
[block
->obj_size_index
] && !block
->free_list
)
2124 block
->is_to_space
= TRUE
;
2125 } END_FOREACH_BLOCK_NO_LOCK
;
2126 if (lazy_sweep
&& !concurrent_sweep
)
2127 binary_protocol_sweep_end (GENERATION_OLD
, TRUE
);
2129 set_sweep_state (SWEEP_STATE_NEED_SWEEPING
, SWEEP_STATE_SWEPT
);
2133 major_finish_major_collection (ScannedObjectCounts
*counts
)
2135 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2136 if (binary_protocol_is_enabled ()) {
2137 counts
->num_scanned_objects
= scanned_objects_list
.next_slot
;
2139 sgen_pointer_queue_sort_uniq (&scanned_objects_list
);
2140 counts
->num_unique_scanned_objects
= scanned_objects_list
.next_slot
;
2142 sgen_pointer_queue_clear (&scanned_objects_list
);
2148 compare_pointers (const void *va
, const void *vb
) {
2149 char *a
= *(char**)va
, *b
= *(char**)vb
;
2158 * This is called with sweep completed and the world stopped.
2161 major_free_swept_blocks (size_t section_reserve
)
2163 SGEN_ASSERT (0, sweep_state
== SWEEP_STATE_SWEPT
, "Sweeping must have finished before freeing blocks");
2165 #if defined(HOST_WIN32) || defined(HOST_ORBIS)
2167 * sgen_free_os_memory () asserts in mono_vfree () because windows doesn't like freeing the middle of
2168 * a VirtualAlloc ()-ed block.
2174 int i
, num_empty_blocks_orig
, num_blocks
, arr_length
;
2176 void **empty_block_arr
;
2177 void **rebuild_next
;
2179 if (num_empty_blocks
<= section_reserve
)
2181 SGEN_ASSERT (0, num_empty_blocks
> 0, "section reserve can't be negative");
2183 num_empty_blocks_orig
= num_empty_blocks
;
2184 empty_block_arr
= (void**)sgen_alloc_internal_dynamic (sizeof (void*) * num_empty_blocks_orig
,
2185 INTERNAL_MEM_MS_BLOCK_INFO_SORT
, FALSE
);
2186 if (!empty_block_arr
)
2190 for (block
= empty_blocks
; block
; block
= *(void**)block
)
2191 empty_block_arr
[i
++] = block
;
2192 SGEN_ASSERT (0, i
== num_empty_blocks
, "empty block count wrong");
2194 sgen_qsort (empty_block_arr
, num_empty_blocks
, sizeof (void*), compare_pointers
);
2197 * We iterate over the free blocks, trying to find MS_BLOCK_ALLOC_NUM
2198 * contiguous ones. If we do, we free them. If that's not enough to get to
2199 * section_reserve, we halve the number of contiguous blocks we're looking
2200 * for and have another go, until we're done with looking for pairs of
2201 * blocks, at which point we give up and go to the fallback.
2203 arr_length
= num_empty_blocks_orig
;
2204 num_blocks
= MS_BLOCK_ALLOC_NUM
;
2205 while (num_empty_blocks
> section_reserve
&& num_blocks
> 1) {
2210 for (i
= 0; i
< arr_length
; ++i
) {
2212 void *block
= empty_block_arr
[i
];
2213 SGEN_ASSERT (6, block
, "we're not shifting correctly");
2215 empty_block_arr
[dest
] = block
;
2217 * This is not strictly necessary, but we're
2220 empty_block_arr
[i
] = NULL
;
2229 SGEN_ASSERT (6, first
>= 0 && d
> first
, "algorithm is wrong");
2231 if ((char*)block
!= ((char*)empty_block_arr
[d
-1]) + ms_block_size
) {
2236 if (d
+ 1 - first
== num_blocks
) {
2238 * We found num_blocks contiguous blocks. Free them
2239 * and null their array entries. As an optimization
2240 * we could, instead of nulling the entries, shift
2241 * the following entries over to the left, while
2245 sgen_free_os_memory (empty_block_arr
[first
], ms_block_size
* num_blocks
, SGEN_ALLOC_HEAP
, MONO_MEM_ACCOUNT_SGEN_MARKSWEEP
);
2246 for (j
= first
; j
<= d
; ++j
)
2247 empty_block_arr
[j
] = NULL
;
2251 num_empty_blocks
-= num_blocks
;
2253 stat_major_blocks_freed
+= num_blocks
;
2254 if (num_blocks
== MS_BLOCK_ALLOC_NUM
)
2255 stat_major_blocks_freed_ideal
+= num_blocks
;
2257 stat_major_blocks_freed_less_ideal
+= num_blocks
;
2262 SGEN_ASSERT (6, dest
<= i
&& dest
<= arr_length
, "array length is off");
2264 SGEN_ASSERT (6, arr_length
== num_empty_blocks
, "array length is off");
2269 /* rebuild empty_blocks free list */
2270 rebuild_next
= (void**)&empty_blocks
;
2271 for (i
= 0; i
< arr_length
; ++i
) {
2272 void *block
= empty_block_arr
[i
];
2273 SGEN_ASSERT (6, block
, "we're missing blocks");
2274 *rebuild_next
= block
;
2275 rebuild_next
= (void**)block
;
2277 *rebuild_next
= NULL
;
2280 sgen_free_internal_dynamic (empty_block_arr
, sizeof (void*) * num_empty_blocks_orig
, INTERNAL_MEM_MS_BLOCK_INFO_SORT
);
2283 SGEN_ASSERT (0, num_empty_blocks
>= 0, "we freed more blocks than we had in the first place?");
2287 * This is our threshold. If there's not more empty than used blocks, we won't
2288 * release uncontiguous blocks, in fear of fragmenting the address space.
2290 if (num_empty_blocks
<= num_major_sections
)
2293 while (num_empty_blocks
> section_reserve
) {
2294 void *next
= *(void**)empty_blocks
;
2295 sgen_free_os_memory (empty_blocks
, ms_block_size
, SGEN_ALLOC_HEAP
, MONO_MEM_ACCOUNT_SGEN_MARKSWEEP
);
2296 empty_blocks
= next
;
2298 * Needs not be atomic because this is running
2303 ++stat_major_blocks_freed
;
2304 ++stat_major_blocks_freed_individual
;
2309 major_pin_objects (SgenGrayQueue
*queue
)
2313 FOREACH_BLOCK_NO_LOCK (block
) {
2314 size_t first_entry
, last_entry
;
2315 SGEN_ASSERT (6, block_is_swept_or_marking (block
), "All blocks must be swept when we're pinning.");
2316 sgen_find_optimized_pin_queue_area (MS_BLOCK_FOR_BLOCK_INFO (block
) + MS_BLOCK_SKIP
, MS_BLOCK_FOR_BLOCK_INFO (block
) + ms_block_size
,
2317 &first_entry
, &last_entry
);
2318 mark_pinned_objects_in_block (block
, first_entry
, last_entry
, queue
);
2319 } END_FOREACH_BLOCK_NO_LOCK
;
2323 major_init_to_space (void)
2328 major_report_pinned_memory_usage (void)
2330 g_assert_not_reached ();
2334 major_get_used_size (void)
2340 * We're holding the GC lock, but the sweep thread might be running. Make sure it's
2341 * finished, then we can iterate over the block array.
2343 major_finish_sweep_checking ();
2345 FOREACH_BLOCK_NO_LOCK (block
) {
2346 int count
= MS_BLOCK_FREE
/ block
->obj_size
;
2348 size
+= count
* block
->obj_size
;
2349 for (iter
= block
->free_list
; iter
; iter
= (void**)*iter
)
2350 size
-= block
->obj_size
;
2351 } END_FOREACH_BLOCK_NO_LOCK
;
2356 /* FIXME: return number of bytes, not of sections */
2358 get_num_major_sections (void)
2360 return num_major_sections
;
2364 * Returns the number of bytes in blocks that were present when the last sweep was
2365 * initiated, and were not freed during the sweep. They are the basis for calculating the
2369 get_bytes_survived_last_sweep (void)
2371 SGEN_ASSERT (0, sweep_state
== SWEEP_STATE_SWEPT
, "Can only query unswept sections after sweep");
2372 return (num_major_sections_before_sweep
- num_major_sections_freed_in_sweep
) * ms_block_size
;
2376 major_handle_gc_param (const char *opt
)
2378 if (g_str_has_prefix (opt
, "evacuation-threshold=")) {
2379 const char *arg
= strchr (opt
, '=') + 1;
2380 int percentage
= atoi (arg
);
2381 if (percentage
< 0 || percentage
> 100) {
2382 fprintf (stderr
, "evacuation-threshold must be an integer in the range 0-100.\n");
2385 evacuation_threshold
= (float)percentage
/ 100.0f
;
2387 } else if (!strcmp (opt
, "lazy-sweep")) {
2390 } else if (!strcmp (opt
, "no-lazy-sweep")) {
2393 } else if (!strcmp (opt
, "concurrent-sweep")) {
2394 concurrent_sweep
= TRUE
;
2396 } else if (!strcmp (opt
, "no-concurrent-sweep")) {
2397 concurrent_sweep
= FALSE
;
2405 major_print_gc_param_usage (void)
2409 " evacuation-threshold=P (where P is a percentage, an integer in 0-100)\n"
2410 " (no-)lazy-sweep\n"
2411 " (no-)concurrent-sweep\n"
2416 * This callback is used to clear cards, move cards to the shadow table and do counting.
2419 major_iterate_block_ranges (sgen_cardtable_block_callback callback
)
2422 gboolean has_references
;
2424 FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK (block
, has_references
) {
2426 callback ((mword
)MS_BLOCK_FOR_BLOCK_INFO (block
), ms_block_size
);
2427 } END_FOREACH_BLOCK_NO_LOCK
;
2431 major_iterate_live_block_ranges (sgen_cardtable_block_callback callback
)
2434 gboolean has_references
;
2436 major_finish_sweep_checking ();
2437 FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK (block
, has_references
) {
2439 callback ((mword
)MS_BLOCK_FOR_BLOCK_INFO (block
), ms_block_size
);
2440 } END_FOREACH_BLOCK_NO_LOCK
;
2443 #ifdef HEAVY_STATISTICS
2444 extern guint64 marked_cards
;
2445 extern guint64 scanned_cards
;
2446 extern guint64 scanned_objects
;
2447 extern guint64 remarked_cards
;
2450 #define CARD_WORDS_PER_BLOCK (CARDS_PER_BLOCK / SIZEOF_VOID_P)
2452 * MS blocks are 16K aligned.
2453 * Cardtables are 4K aligned, at least.
2454 * This means that the cardtable of a given block is 32 bytes aligned.
2457 initial_skip_card (guint8
*card_data
)
2459 mword
*cards
= (mword
*)card_data
;
2462 for (i
= 0; i
< CARD_WORDS_PER_BLOCK
; ++i
) {
2468 if (i
== CARD_WORDS_PER_BLOCK
)
2469 return card_data
+ CARDS_PER_BLOCK
;
2471 #if defined(__i386__) && defined(__GNUC__)
2472 return card_data
+ i
* 4 + (__builtin_ffs (card
) - 1) / 8;
2473 #elif defined(__x86_64__) && defined(__GNUC__)
2474 return card_data
+ i
* 8 + (__builtin_ffsll (card
) - 1) / 8;
2475 #elif defined(__s390x__) && defined(__GNUC__)
2476 return card_data
+ i
* 8 + (__builtin_ffsll (GUINT64_TO_LE(card
)) - 1) / 8;
2478 for (i
= i
* SIZEOF_VOID_P
; i
< CARDS_PER_BLOCK
; ++i
) {
2480 return &card_data
[i
];
2486 #define MS_BLOCK_OBJ_INDEX_FAST(o,b,os) (((char*)(o) - ((b) + MS_BLOCK_SKIP)) / (os))
2487 #define MS_BLOCK_OBJ_FAST(b,os,i) ((b) + MS_BLOCK_SKIP + (os) * (i))
2488 #define MS_OBJ_ALLOCED_FAST(o,b) (*(void**)(o) && (*(char**)(o) < (b) || *(char**)(o) >= (b) + ms_block_size))
2491 scan_card_table_for_block (MSBlockInfo
*block
, CardTableScanType scan_type
, ScanCopyContext ctx
)
2493 SgenGrayQueue
*queue
= ctx
.queue
;
2494 ScanObjectFunc scan_func
= ctx
.ops
->scan_object
;
2496 * FIXME: On systems with very large pages, we allocate fairly large
2497 * arrays on the stack here. This shouldn't be a problem once block
2498 * size is no longer required to be a multiple of the system page size.
2500 #ifndef SGEN_HAVE_OVERLAPPING_CARDS
2501 guint8
*cards_copy
= alloca (sizeof (guint8
) * CARDS_PER_BLOCK
);
2503 guint8
*cards_preclean
= alloca (sizeof (guint8
) * CARDS_PER_BLOCK
);
2504 gboolean small_objects
;
2507 guint8
*card_data
, *card_base
;
2508 guint8
*card_data_end
;
2509 char *scan_front
= NULL
;
2511 /* The concurrent mark doesn't enter evacuating blocks */
2512 if (scan_type
== CARDTABLE_SCAN_MOD_UNION_PRECLEAN
&& major_block_is_evacuating (block
))
2515 block_obj_size
= block
->obj_size
;
2516 small_objects
= block_obj_size
< CARD_SIZE_IN_BYTES
;
2518 block_start
= MS_BLOCK_FOR_BLOCK_INFO (block
);
2521 * This is safe in face of card aliasing for the following reason:
2523 * Major blocks are 16k aligned, or 32 cards aligned.
2524 * Cards aliasing happens in powers of two, so as long as major blocks are aligned to their
2525 * sizes, they won't overflow the cardtable overlap modulus.
2527 if (scan_type
& CARDTABLE_SCAN_MOD_UNION
) {
2528 card_data
= card_base
= block
->cardtable_mod_union
;
2530 * This happens when the nursery collection that precedes finishing
2531 * the concurrent collection allocates new major blocks.
2536 if (scan_type
== CARDTABLE_SCAN_MOD_UNION_PRECLEAN
) {
2537 sgen_card_table_preclean_mod_union (card_data
, cards_preclean
, CARDS_PER_BLOCK
);
2538 card_data
= card_base
= cards_preclean
;
2541 #ifdef SGEN_HAVE_OVERLAPPING_CARDS
2542 card_data
= card_base
= sgen_card_table_get_card_scan_address ((mword
)block_start
);
2544 if (!sgen_card_table_get_card_data (cards_copy
, (mword
)block_start
, CARDS_PER_BLOCK
))
2546 card_data
= card_base
= cards_copy
;
2549 card_data_end
= card_data
+ CARDS_PER_BLOCK
;
2551 card_data
+= MS_BLOCK_SKIP
>> CARD_BITS
;
2553 card_data
= initial_skip_card (card_data
);
2554 while (card_data
< card_data_end
) {
2555 size_t card_index
, first_object_index
;
2558 char *first_obj
, *obj
;
2560 HEAVY_STAT (++scanned_cards
);
2567 card_index
= card_data
- card_base
;
2568 start
= (char*)(block_start
+ card_index
* CARD_SIZE_IN_BYTES
);
2569 end
= start
+ CARD_SIZE_IN_BYTES
;
2571 if (!block_is_swept_or_marking (block
))
2572 sweep_block (block
);
2574 HEAVY_STAT (++marked_cards
);
2577 sgen_card_table_prepare_card_for_scanning (card_data
);
2580 * If the card we're looking at starts at or in the block header, we
2581 * must start at the first object in the block, without calculating
2582 * the index of the object we're hypothetically starting at, because
2583 * it would be negative.
2585 if (card_index
<= (MS_BLOCK_SKIP
>> CARD_BITS
))
2586 first_object_index
= 0;
2588 first_object_index
= MS_BLOCK_OBJ_INDEX_FAST (start
, block_start
, block_obj_size
);
2590 obj
= first_obj
= (char*)MS_BLOCK_OBJ_FAST (block_start
, block_obj_size
, first_object_index
);
2592 binary_protocol_card_scan (first_obj
, end
- first_obj
);
2595 if (obj
< scan_front
|| !MS_OBJ_ALLOCED_FAST (obj
, block_start
))
2598 if (scan_type
& CARDTABLE_SCAN_MOD_UNION
) {
2599 /* FIXME: do this more efficiently */
2601 MS_CALC_MARK_BIT (w
, b
, obj
);
2602 if (!MS_MARK_BIT (block
, w
, b
))
2606 GCObject
*object
= (GCObject
*)obj
;
2608 if (small_objects
) {
2609 HEAVY_STAT (++scanned_objects
);
2610 scan_func (object
, sgen_obj_get_descriptor (object
), queue
);
2612 size_t offset
= sgen_card_table_get_card_offset (obj
, block_start
);
2613 sgen_cardtable_scan_object (object
, block_obj_size
, card_base
+ offset
, ctx
);
2616 obj
+= block_obj_size
;
2617 g_assert (scan_front
<= obj
);
2621 HEAVY_STAT (if (*card_data
) ++remarked_cards
);
2626 card_data
= card_base
+ sgen_card_table_get_card_offset (obj
, block_start
);
2631 major_scan_card_table (CardTableScanType scan_type
, ScanCopyContext ctx
, int job_index
, int job_split_count
, int block_count
)
2634 gboolean has_references
, was_sweeping
, skip_scan
;
2635 int first_block
, last_block
, index
;
2638 * The last_block's index is at least (num_major_sections - 1) since we
2639 * can have nulls in the allocated_blocks list. The last worker will
2640 * scan the left-overs of the list. We expect few null entries in the
2641 * allocated_blocks list, therefore using num_major_sections for computing
2642 * block_count shouldn't affect work distribution.
2644 first_block
= block_count
* job_index
;
2645 if (job_index
== job_split_count
- 1)
2646 last_block
= allocated_blocks
.next_slot
;
2648 last_block
= block_count
* (job_index
+ 1);
2650 if (!concurrent_mark
)
2651 g_assert (scan_type
== CARDTABLE_SCAN_GLOBAL
);
2653 if (scan_type
!= CARDTABLE_SCAN_GLOBAL
)
2654 SGEN_ASSERT (0, !sweep_in_progress (), "Sweep should be finished when we scan mod union card table");
2655 was_sweeping
= sweep_in_progress ();
2657 binary_protocol_major_card_table_scan_start (sgen_timestamp (), scan_type
& CARDTABLE_SCAN_MOD_UNION
);
2658 FOREACH_BLOCK_RANGE_HAS_REFERENCES_NO_LOCK (block
, first_block
, last_block
, index
, has_references
) {
2659 #ifdef PREFETCH_CARDS
2660 int prefetch_index
= index
+ 6;
2661 if (prefetch_index
< allocated_blocks
.next_slot
) {
2662 MSBlockInfo
*prefetch_block
= BLOCK_UNTAG (*sgen_array_list_get_slot (&allocated_blocks
, prefetch_index
));
2663 PREFETCH_READ (prefetch_block
);
2664 if (scan_type
== CARDTABLE_SCAN_GLOBAL
) {
2665 guint8
*prefetch_cards
= sgen_card_table_get_card_scan_address ((mword
)MS_BLOCK_FOR_BLOCK_INFO (prefetch_block
));
2666 PREFETCH_WRITE (prefetch_cards
);
2667 PREFETCH_WRITE (prefetch_cards
+ 32);
2671 if (!has_references
)
2675 if (scan_type
== CARDTABLE_SCAN_GLOBAL
) {
2676 gpointer
*card_start
= (gpointer
*) sgen_card_table_get_card_scan_address ((mword
)MS_BLOCK_FOR_BLOCK_INFO (block
));
2677 gboolean has_dirty_cards
= FALSE
;
2679 for (i
= 0; i
< CARDS_PER_BLOCK
/ sizeof(gpointer
); i
++) {
2680 if (card_start
[i
]) {
2681 has_dirty_cards
= TRUE
;
2685 if (!has_dirty_cards
) {
2689 * After the start of the concurrent collections, blocks change state
2690 * to marking. We should not sweep it in that case. We can't race with
2691 * sweep start since we are in a nursery collection. Also avoid CAS-ing
2693 if (sweep_in_progress ()) {
2694 skip_scan
= !ensure_block_is_checked_for_sweeping (index
, TRUE
, NULL
);
2695 } else if (was_sweeping
) {
2696 /* Recheck in case sweep finished after dereferencing the slot */
2697 skip_scan
= *sgen_array_list_get_slot (&allocated_blocks
, index
) == 0;
2702 scan_card_table_for_block (block
, scan_type
, ctx
);
2703 } END_FOREACH_BLOCK_RANGE_NO_LOCK
;
2704 binary_protocol_major_card_table_scan_end (sgen_timestamp (), scan_type
& CARDTABLE_SCAN_MOD_UNION
);
2708 major_count_cards (long long *num_total_cards
, long long *num_marked_cards
)
2711 gboolean has_references
;
2712 long long total_cards
= 0;
2713 long long marked_cards
= 0;
2715 if (sweep_in_progress ()) {
2716 *num_total_cards
= -1;
2717 *num_marked_cards
= -1;
2721 FOREACH_BLOCK_HAS_REFERENCES_NO_LOCK (block
, has_references
) {
2722 guint8
*cards
= sgen_card_table_get_card_scan_address ((mword
) MS_BLOCK_FOR_BLOCK_INFO (block
));
2725 if (!has_references
)
2728 total_cards
+= CARDS_PER_BLOCK
;
2729 for (i
= 0; i
< CARDS_PER_BLOCK
; ++i
) {
2733 } END_FOREACH_BLOCK_NO_LOCK
;
2735 *num_total_cards
= total_cards
;
2736 *num_marked_cards
= marked_cards
;
2740 update_cardtable_mod_union (void)
2744 FOREACH_BLOCK_NO_LOCK (block
) {
2745 gpointer
*card_start
= (gpointer
*) sgen_card_table_get_card_address ((mword
)MS_BLOCK_FOR_BLOCK_INFO (block
));
2746 gboolean has_dirty_cards
= FALSE
;
2748 for (i
= 0; i
< CARDS_PER_BLOCK
/ sizeof(gpointer
); i
++) {
2749 if (card_start
[i
]) {
2750 has_dirty_cards
= TRUE
;
2754 if (has_dirty_cards
) {
2756 guint8
*mod_union
= get_cardtable_mod_union_for_block (block
, TRUE
);
2757 sgen_card_table_update_mod_union (mod_union
, MS_BLOCK_FOR_BLOCK_INFO (block
), ms_block_size
, &num_cards
);
2758 SGEN_ASSERT (6, num_cards
== CARDS_PER_BLOCK
, "Number of cards calculation is wrong");
2760 } END_FOREACH_BLOCK_NO_LOCK
;
2763 #undef pthread_create
2766 post_param_init (SgenMajorCollector
*collector
)
2768 collector
->sweeps_lazily
= lazy_sweep
;
2772 * We are guaranteed to be called by the worker in question.
2773 * This provides initialization for threads that plan to do
2774 * parallel object allocation. We need to store these lists
2775 * in additional data structures so we can traverse them
2776 * at major/sweep start.
2779 sgen_init_block_free_lists (gpointer
*list_p
)
2782 MSBlockInfo
***worker_free_blocks
= (MSBlockInfo
***) mono_native_tls_get_value (worker_block_free_list_key
);
2785 * For simplification, a worker thread uses the same free block lists,
2786 * regardless of the context it is part of (major/minor).
2788 if (worker_free_blocks
) {
2789 *list_p
= (gpointer
)worker_free_blocks
;
2793 worker_free_blocks
= (MSBlockInfo
***) sgen_alloc_internal_dynamic (sizeof (MSBlockInfo
**) * MS_BLOCK_TYPE_MAX
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2795 for (i
= 0; i
< MS_BLOCK_TYPE_MAX
; i
++)
2796 worker_free_blocks
[i
] = (MSBlockInfo
**) sgen_alloc_internal_dynamic (sizeof (MSBlockInfo
*) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2798 *list_p
= (gpointer
)worker_free_blocks
;
2800 mono_native_tls_set_value (worker_block_free_list_key
, worker_free_blocks
);
2804 sgen_marksweep_init_internal (SgenMajorCollector
*collector
, gboolean is_concurrent
, gboolean is_parallel
)
2808 ms_block_size
= mono_pagesize ();
2810 if (ms_block_size
< MS_BLOCK_SIZE_MIN
)
2811 ms_block_size
= MS_BLOCK_SIZE_MIN
;
2813 sgen_register_fixed_internal_mem_type (INTERNAL_MEM_MS_BLOCK_INFO
, SIZEOF_MS_BLOCK_INFO
);
2815 if (mono_cpu_count () <= 1)
2816 is_parallel
= FALSE
;
2818 num_block_obj_sizes
= ms_calculate_block_obj_sizes (MS_BLOCK_OBJ_SIZE_FACTOR
, NULL
);
2819 block_obj_sizes
= (int *)sgen_alloc_internal_dynamic (sizeof (int) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2820 ms_calculate_block_obj_sizes (MS_BLOCK_OBJ_SIZE_FACTOR
, block_obj_sizes
);
2822 evacuate_block_obj_sizes
= (gboolean
*)sgen_alloc_internal_dynamic (sizeof (gboolean
) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2823 for (i
= 0; i
< num_block_obj_sizes
; ++i
)
2824 evacuate_block_obj_sizes
[i
] = FALSE
;
2826 sweep_slots_available
= (size_t *)sgen_alloc_internal_dynamic (sizeof (size_t) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2827 sweep_slots_used
= (size_t *)sgen_alloc_internal_dynamic (sizeof (size_t) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2828 sweep_num_blocks
= (size_t *)sgen_alloc_internal_dynamic (sizeof (size_t) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2833 g_print ("block object sizes:\n");
2834 for (i = 0; i < num_block_obj_sizes; ++i)
2835 g_print ("%d\n", block_obj_sizes [i]);
2839 for (i
= 0; i
< MS_BLOCK_TYPE_MAX
; ++i
)
2840 free_block_lists
[i
] = (MSBlockInfo
*volatile *)sgen_alloc_internal_dynamic (sizeof (MSBlockInfo
*) * num_block_obj_sizes
, INTERNAL_MEM_MS_TABLES
, TRUE
);
2842 for (i
= 0; i
< MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES
; ++i
)
2843 fast_block_obj_size_indexes
[i
] = ms_find_block_obj_size_index (i
* 8);
2844 for (i
= 0; i
< MS_NUM_FAST_BLOCK_OBJ_SIZE_INDEXES
* 8; ++i
)
2845 g_assert (MS_BLOCK_OBJ_SIZE_INDEX (i
) == ms_find_block_obj_size_index (i
));
2847 /* We can do this because we always init the minor before the major */
2848 if (is_parallel
|| sgen_get_minor_collector ()->is_parallel
)
2849 mono_native_tls_alloc (&worker_block_free_list_key
, NULL
);
2851 mono_counters_register ("# major blocks allocated", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_alloced
);
2852 mono_counters_register ("# major blocks freed", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_freed
);
2853 mono_counters_register ("# major blocks lazy swept", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_lazy_swept
);
2854 mono_counters_register ("# major blocks freed ideally", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_freed_ideal
);
2855 mono_counters_register ("# major blocks freed less ideally", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_freed_less_ideal
);
2856 mono_counters_register ("# major blocks freed individually", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_freed_individual
);
2857 mono_counters_register ("# major blocks allocated less ideally", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_major_blocks_alloced_less_ideal
);
2859 collector
->section_size
= ms_block_size
;
2861 concurrent_mark
= is_concurrent
;
2862 collector
->is_concurrent
= is_concurrent
;
2863 collector
->is_parallel
= is_parallel
;
2864 collector
->get_and_reset_num_major_objects_marked
= major_get_and_reset_num_major_objects_marked
;
2865 collector
->supports_cardtable
= TRUE
;
2867 collector
->alloc_heap
= major_alloc_heap
;
2868 collector
->is_object_live
= major_is_object_live
;
2869 collector
->alloc_small_pinned_obj
= major_alloc_small_pinned_obj
;
2870 collector
->alloc_degraded
= major_alloc_degraded
;
2872 collector
->alloc_object
= major_alloc_object
;
2873 collector
->alloc_object_par
= major_alloc_object_par
;
2874 collector
->free_pinned_object
= free_pinned_object
;
2875 collector
->iterate_objects
= major_iterate_objects
;
2876 collector
->free_non_pinned_object
= major_free_non_pinned_object
;
2877 collector
->pin_objects
= major_pin_objects
;
2878 collector
->pin_major_object
= pin_major_object
;
2879 collector
->scan_card_table
= major_scan_card_table
;
2880 collector
->iterate_live_block_ranges
= major_iterate_live_block_ranges
;
2881 collector
->iterate_block_ranges
= major_iterate_block_ranges
;
2882 if (is_concurrent
) {
2883 collector
->update_cardtable_mod_union
= update_cardtable_mod_union
;
2884 collector
->get_cardtable_mod_union_for_reference
= major_get_cardtable_mod_union_for_reference
;
2886 collector
->init_to_space
= major_init_to_space
;
2887 collector
->sweep
= major_sweep
;
2888 collector
->have_swept
= major_have_swept
;
2889 collector
->finish_sweeping
= major_finish_sweep_checking
;
2890 collector
->free_swept_blocks
= major_free_swept_blocks
;
2891 collector
->check_scan_starts
= major_check_scan_starts
;
2892 collector
->dump_heap
= major_dump_heap
;
2893 collector
->get_used_size
= major_get_used_size
;
2894 collector
->start_nursery_collection
= major_start_nursery_collection
;
2895 collector
->finish_nursery_collection
= major_finish_nursery_collection
;
2896 collector
->start_major_collection
= major_start_major_collection
;
2897 collector
->finish_major_collection
= major_finish_major_collection
;
2898 collector
->ptr_is_in_non_pinned_space
= major_ptr_is_in_non_pinned_space
;
2899 collector
->ptr_is_from_pinned_alloc
= ptr_is_from_pinned_alloc
;
2900 collector
->report_pinned_memory_usage
= major_report_pinned_memory_usage
;
2901 collector
->get_num_major_sections
= get_num_major_sections
;
2902 collector
->get_bytes_survived_last_sweep
= get_bytes_survived_last_sweep
;
2903 collector
->handle_gc_param
= major_handle_gc_param
;
2904 collector
->print_gc_param_usage
= major_print_gc_param_usage
;
2905 collector
->post_param_init
= post_param_init
;
2906 collector
->is_valid_object
= major_is_valid_object
;
2907 collector
->describe_pointer
= major_describe_pointer
;
2908 collector
->count_cards
= major_count_cards
;
2909 collector
->init_block_free_lists
= sgen_init_block_free_lists
;
2911 collector
->major_ops_serial
.copy_or_mark_object
= major_copy_or_mark_object_canonical
;
2912 collector
->major_ops_serial
.scan_object
= major_scan_object_with_evacuation
;
2913 collector
->major_ops_serial
.scan_ptr_field
= major_scan_ptr_field_with_evacuation
;
2914 collector
->major_ops_serial
.drain_gray_stack
= drain_gray_stack
;
2915 if (is_concurrent
) {
2916 collector
->major_ops_concurrent_start
.copy_or_mark_object
= major_copy_or_mark_object_concurrent_canonical
;
2917 collector
->major_ops_concurrent_start
.scan_object
= major_scan_object_concurrent_with_evacuation
;
2918 collector
->major_ops_concurrent_start
.scan_vtype
= major_scan_vtype_concurrent_with_evacuation
;
2919 collector
->major_ops_concurrent_start
.scan_ptr_field
= major_scan_ptr_field_concurrent_with_evacuation
;
2920 collector
->major_ops_concurrent_start
.drain_gray_stack
= drain_gray_stack_concurrent
;
2922 collector
->major_ops_concurrent_finish
.copy_or_mark_object
= major_copy_or_mark_object_concurrent_finish_canonical
;
2923 collector
->major_ops_concurrent_finish
.scan_object
= major_scan_object_with_evacuation
;
2924 collector
->major_ops_concurrent_finish
.scan_vtype
= major_scan_vtype_with_evacuation
;
2925 collector
->major_ops_concurrent_finish
.scan_ptr_field
= major_scan_ptr_field_with_evacuation
;
2926 collector
->major_ops_concurrent_finish
.drain_gray_stack
= drain_gray_stack
;
2929 collector
->major_ops_conc_par_start
.copy_or_mark_object
= major_copy_or_mark_object_concurrent_par_canonical
;
2930 collector
->major_ops_conc_par_start
.scan_object
= major_scan_object_concurrent_par_with_evacuation
;
2931 collector
->major_ops_conc_par_start
.scan_vtype
= major_scan_vtype_concurrent_par_with_evacuation
;
2932 collector
->major_ops_conc_par_start
.scan_ptr_field
= major_scan_ptr_field_concurrent_par_with_evacuation
;
2933 collector
->major_ops_conc_par_start
.drain_gray_stack
= drain_gray_stack_concurrent_par
;
2935 collector
->major_ops_conc_par_finish
.copy_or_mark_object
= major_copy_or_mark_object_concurrent_par_finish_canonical
;
2936 collector
->major_ops_conc_par_finish
.scan_object
= major_scan_object_par_with_evacuation
;
2937 collector
->major_ops_conc_par_finish
.scan_vtype
= major_scan_vtype_par_with_evacuation
;
2938 collector
->major_ops_conc_par_finish
.scan_ptr_field
= major_scan_ptr_field_par_with_evacuation
;
2939 collector
->major_ops_conc_par_finish
.drain_gray_stack
= drain_gray_stack_par
;
2943 #ifdef HEAVY_STATISTICS
2944 mono_counters_register ("Optimized copy", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy
);
2945 mono_counters_register ("Optimized copy nursery", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_nursery
);
2946 mono_counters_register ("Optimized copy nursery forwarded", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_nursery_forwarded
);
2947 mono_counters_register ("Optimized copy nursery pinned", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_nursery_pinned
);
2948 mono_counters_register ("Optimized copy major", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_major
);
2949 mono_counters_register ("Optimized copy major small fast", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_major_small_fast
);
2950 mono_counters_register ("Optimized copy major small slow", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_major_small_slow
);
2951 mono_counters_register ("Optimized copy major small evacuate", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_major_small_evacuate
);
2952 mono_counters_register ("Optimized copy major large", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_copy_major_large
);
2953 mono_counters_register ("Optimized major scan", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_major_scan
);
2954 mono_counters_register ("Optimized major scan no refs", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_optimized_major_scan_no_refs
);
2956 mono_counters_register ("Gray stack drain loops", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_drain_loops
);
2957 mono_counters_register ("Gray stack prefetch fills", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_drain_prefetch_fills
);
2958 mono_counters_register ("Gray stack prefetch failures", MONO_COUNTER_GC
| MONO_COUNTER_ULONG
, &stat_drain_prefetch_fill_failures
);
2961 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
2962 mono_os_mutex_init (&scanned_objects_list_lock
);
2965 SGEN_ASSERT (0, SGEN_MAX_SMALL_OBJ_SIZE
<= MS_BLOCK_FREE
/ 2, "MAX_SMALL_OBJ_SIZE must be at most MS_BLOCK_FREE / 2");
2967 /*cardtable requires major pages to be 8 cards aligned*/
2968 g_assert ((ms_block_size
% (8 * CARD_SIZE_IN_BYTES
)) == 0);
2970 if (is_concurrent
&& is_parallel
)
2971 sgen_workers_create_context (GENERATION_OLD
, mono_cpu_count ());
2972 else if (is_concurrent
)
2973 sgen_workers_create_context (GENERATION_OLD
, 1);
2975 if (concurrent_sweep
)
2976 sweep_pool_context
= sgen_thread_pool_create_context (1, NULL
, NULL
, NULL
, NULL
, NULL
);
2980 sgen_marksweep_init (SgenMajorCollector
*collector
)
2982 sgen_marksweep_init_internal (collector
, FALSE
, FALSE
);
2986 sgen_marksweep_conc_init (SgenMajorCollector
*collector
)
2988 sgen_marksweep_init_internal (collector
, TRUE
, FALSE
);
2992 sgen_marksweep_conc_par_init (SgenMajorCollector
*collector
)
2994 sgen_marksweep_init_internal (collector
, TRUE
, TRUE
);