1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/heap/scavenger.h"
#include "src/heap/barrier.h"
#include "src/heap/heap-inl.h"
#include "src/heap/mark-compact-inl.h"
#include "src/heap/objects-visiting-inl.h"
#include "src/heap/scavenger-inl.h"
#include "src/heap/sweeper.h"
#include "src/objects-body-descriptors-inl.h"
namespace v8 {
namespace internal {
class IterateAndScavengePromotedObjectsVisitor final : public ObjectVisitor {
public:
IterateAndScavengePromotedObjectsVisitor(Heap* heap, Scavenger* scavenger,
bool record_slots)
: heap_(heap), scavenger_(scavenger), record_slots_(record_slots) {}
inline void VisitPointers(HeapObject* host, Object** start,
Object** end) final {
for (Address slot_address = reinterpret_cast<Address>(start);
slot_address < reinterpret_cast<Address>(end);
slot_address += kPointerSize) {
Object** slot = reinterpret_cast<Object**>(slot_address);
Object* target = *slot;
scavenger_->PageMemoryFence(target);
if (target->IsHeapObject()) {
if (heap_->InFromSpace(target)) {
scavenger_->ScavengeObject(reinterpret_cast<HeapObject**>(slot),
HeapObject::cast(target));
target = *slot;
scavenger_->PageMemoryFence(target);
if (heap_->InNewSpace(target)) {
SLOW_DCHECK(target->IsHeapObject());
SLOW_DCHECK(heap_->InToSpace(target));
RememberedSet<OLD_TO_NEW>::Insert(Page::FromAddress(slot_address),
slot_address);
}
SLOW_DCHECK(!MarkCompactCollector::IsOnEvacuationCandidate(
HeapObject::cast(target)));
} else if (record_slots_ &&
MarkCompactCollector::IsOnEvacuationCandidate(
HeapObject::cast(target))) {
heap_->mark_compact_collector()->RecordSlot(host, slot, target);
}
}
}
}
private:
Heap* const heap_;
Scavenger* const scavenger_;
const bool record_slots_;
};
Scavenger::Scavenger(Heap* heap, bool is_logging, CopiedList* copied_list,
PromotionList* promotion_list, int task_id)
: heap_(heap),
promotion_list_(promotion_list, task_id),
copied_list_(copied_list, task_id),
local_pretenuring_feedback_(kInitialLocalPretenuringFeedbackCapacity),
copied_size_(0),
promoted_size_(0),
allocator_(heap),
is_logging_(is_logging),
is_incremental_marking_(heap->incremental_marking()->IsMarking()),
is_compacting_(heap->incremental_marking()->IsCompacting()) {}
void Scavenger::IterateAndScavengePromotedObject(HeapObject* target, int size) {
// We are not collecting slots on new space objects during mutation thus we
// have to scan for pointers to evacuation candidates when we promote
// objects. But we should not record any slots in non-black objects. Grey
// object's slots would be rescanned. White object might not survive until
// the end of collection it would be a violation of the invariant to record
// its slots.
const bool record_slots =
is_compacting_ &&
heap()->incremental_marking()->atomic_marking_state()->IsBlack(target);
IterateAndScavengePromotedObjectsVisitor visitor(heap(), this, record_slots);
target->IterateBody(target->map()->instance_type(), size, &visitor);
}
void Scavenger::AddPageToSweeperIfNecessary(MemoryChunk* page) {
AllocationSpace space = page->owner()->identity();
if ((space == OLD_SPACE) && !page->SweepingDone()) {
heap()->mark_compact_collector()->sweeper()->AddPage(
space, reinterpret_cast<Page*>(page),
Sweeper::READD_TEMPORARY_REMOVED_PAGE);
}
}
void Scavenger::ScavengePage(MemoryChunk* page) {
CodePageMemoryModificationScope memory_modification_scope(page);
RememberedSet<OLD_TO_NEW>::Iterate(
page,
[this](Address addr) { return CheckAndScavengeObject(heap_, addr); },
SlotSet::KEEP_EMPTY_BUCKETS);
RememberedSet<OLD_TO_NEW>::IterateTyped(
page, [this](SlotType type, Address host_addr, Address addr) {
return UpdateTypedSlotHelper::UpdateTypedSlot(
heap_->isolate(), type, addr, [this](Object** addr) {
return CheckAndScavengeObject(heap(),
reinterpret_cast<Address>(addr));
});
});
AddPageToSweeperIfNecessary(page);
}
void Scavenger::Process(OneshotBarrier* barrier) {
// Threshold when to switch processing the promotion list to avoid
// allocating too much backing store in the worklist.
const int kProcessPromotionListThreshold = kPromotionListSegmentSize / 2;
ScavengeVisitor scavenge_visitor(heap(), this);
const bool have_barrier = barrier != nullptr;
bool done;
size_t objects = 0;
do {
done = true;
ObjectAndSize object_and_size;
while ((promotion_list_.LocalPushSegmentSize() <
kProcessPromotionListThreshold) &&
copied_list_.Pop(&object_and_size)) {
scavenge_visitor.Visit(object_and_size.first);
done = false;
if (have_barrier && ((++objects % kInterruptThreshold) == 0)) {
if (!copied_list_.IsGlobalPoolEmpty()) {
barrier->NotifyAll();
}
}
}
while (promotion_list_.Pop(&object_and_size)) {
HeapObject* target = object_and_size.first;
int size = object_and_size.second;
DCHECK(!target->IsMap());
IterateAndScavengePromotedObject(target, size);
done = false;
if (have_barrier && ((++objects % kInterruptThreshold) == 0)) {
if (!promotion_list_.IsGlobalPoolEmpty()) {
barrier->NotifyAll();
}
}
}
} while (!done);
}
void Scavenger::Finalize() {
heap()->MergeAllocationSitePretenuringFeedback(local_pretenuring_feedback_);
heap()->IncrementSemiSpaceCopiedObjectSize(copied_size_);
heap()->IncrementPromotedObjectsSize(promoted_size_);
allocator_.Finalize();
}
void RootScavengeVisitor::VisitRootPointer(Root root, Object** p) {
ScavengePointer(p);
}
void RootScavengeVisitor::VisitRootPointers(Root root, Object** start,
Object** end) {
// Copy all HeapObject pointers in [start, end)
for (Object** p = start; p < end; p++) ScavengePointer(p);
}
void RootScavengeVisitor::ScavengePointer(Object** p) {
Object* object = *p;
if (!heap_->InNewSpace(object)) return;
scavenger_->ScavengeObject(reinterpret_cast<HeapObject**>(p),
reinterpret_cast<HeapObject*>(object));
}
} // namespace internal
} // namespace v8
|
