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
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "bump_pointer_space.h"
#include "bump_pointer_space-inl.h"
#include "mirror/object-inl.h"
#include "mirror/class-inl.h"
#include "thread_list.h"
namespace art {
namespace gc {
namespace space {
BumpPointerSpace* BumpPointerSpace::Create(const std::string& name, size_t capacity,
byte* requested_begin) {
capacity = RoundUp(capacity, kPageSize);
std::string error_msg;
UniquePtr<MemMap> mem_map(MemMap::MapAnonymous(name.c_str(), requested_begin, capacity,
PROT_READ | PROT_WRITE, true, &error_msg));
if (mem_map.get() == nullptr) {
LOG(ERROR) << "Failed to allocate pages for alloc space (" << name << ") of size "
<< PrettySize(capacity) << " with message " << error_msg;
return nullptr;
}
return new BumpPointerSpace(name, mem_map.release());
}
BumpPointerSpace::BumpPointerSpace(const std::string& name, byte* begin, byte* limit)
: ContinuousMemMapAllocSpace(name, nullptr, begin, begin, limit,
kGcRetentionPolicyAlwaysCollect),
growth_end_(limit),
objects_allocated_(0), bytes_allocated_(0),
block_lock_("Block lock"),
num_blocks_(0) {
CHECK_GE(Capacity(), sizeof(BlockHeader));
end_ += sizeof(BlockHeader);
}
BumpPointerSpace::BumpPointerSpace(const std::string& name, MemMap* mem_map)
: ContinuousMemMapAllocSpace(name, mem_map, mem_map->Begin(), mem_map->Begin(), mem_map->End(),
kGcRetentionPolicyAlwaysCollect),
growth_end_(mem_map->End()),
objects_allocated_(0), bytes_allocated_(0),
block_lock_("Block lock"),
num_blocks_(0) {
CHECK_GE(Capacity(), sizeof(BlockHeader));
end_ += sizeof(BlockHeader);
}
mirror::Object* BumpPointerSpace::Alloc(Thread*, size_t num_bytes, size_t* bytes_allocated) {
num_bytes = RoundUp(num_bytes, kAlignment);
mirror::Object* ret = AllocNonvirtual(num_bytes);
if (LIKELY(ret != nullptr)) {
*bytes_allocated = num_bytes;
}
return ret;
}
size_t BumpPointerSpace::AllocationSize(mirror::Object* obj) {
return AllocationSizeNonvirtual(obj);
}
void BumpPointerSpace::Clear() {
// Release the pages back to the operating system.
CHECK_NE(madvise(Begin(), Limit() - Begin(), MADV_DONTNEED), -1) << "madvise failed";
// Reset the end of the space back to the beginning, we move the end forward as we allocate
// objects.
SetEnd(Begin() + sizeof(BlockHeader));
objects_allocated_ = 0;
bytes_allocated_ = 0;
growth_end_ = Limit();
{
MutexLock mu(Thread::Current(), block_lock_);
num_blocks_ = 0;
}
}
void BumpPointerSpace::Dump(std::ostream& os) const {
os << reinterpret_cast<void*>(Begin()) << "-" << reinterpret_cast<void*>(End()) << " - "
<< reinterpret_cast<void*>(Limit());
}
mirror::Object* BumpPointerSpace::GetNextObject(mirror::Object* obj) {
const uintptr_t position = reinterpret_cast<uintptr_t>(obj) + obj->SizeOf();
return reinterpret_cast<mirror::Object*>(RoundUp(position, kAlignment));
}
void BumpPointerSpace::RevokeThreadLocalBuffers(Thread* thread) {
MutexLock mu(Thread::Current(), block_lock_);
RevokeThreadLocalBuffersLocked(thread);
}
void BumpPointerSpace::RevokeAllThreadLocalBuffers() {
Thread* self = Thread::Current();
MutexLock mu(self, *Locks::runtime_shutdown_lock_);
MutexLock mu2(self, *Locks::thread_list_lock_);
// TODO: Not do a copy of the thread list?
std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList();
for (Thread* thread : thread_list) {
RevokeThreadLocalBuffers(thread);
}
}
void BumpPointerSpace::UpdateMainBlock() {
BlockHeader* header = reinterpret_cast<BlockHeader*>(Begin());
header->size_ = Size() - sizeof(BlockHeader);
DCHECK_EQ(num_blocks_, 0U);
}
// Returns the start of the storage.
byte* BumpPointerSpace::AllocBlock(size_t bytes) {
bytes = RoundUp(bytes, kAlignment);
if (!num_blocks_) {
UpdateMainBlock();
}
byte* storage = reinterpret_cast<byte*>(
AllocNonvirtualWithoutAccounting(bytes + sizeof(BlockHeader)));
if (LIKELY(storage != nullptr)) {
BlockHeader* header = reinterpret_cast<BlockHeader*>(storage);
header->size_ = bytes; // Write out the block header.
storage += sizeof(BlockHeader);
++num_blocks_;
}
return storage;
}
void BumpPointerSpace::Walk(ObjectVisitorCallback callback, void* arg) {
byte* pos = Begin();
{
MutexLock mu(Thread::Current(), block_lock_);
// If we have 0 blocks then we need to update the main header since we have bump pointer style
// allocation into an unbounded region (actually bounded by Capacity()).
if (num_blocks_ == 0) {
UpdateMainBlock();
}
}
while (pos < End()) {
BlockHeader* header = reinterpret_cast<BlockHeader*>(pos);
size_t block_size = header->size_;
pos += sizeof(BlockHeader); // Skip the header so that we know where the objects
mirror::Object* obj = reinterpret_cast<mirror::Object*>(pos);
const mirror::Object* end = reinterpret_cast<const mirror::Object*>(pos + block_size);
CHECK_LE(reinterpret_cast<const byte*>(end), End());
// We don't know how many objects are allocated in the current block. When we hit a null class
// assume its the end. TODO: Have a thread update the header when it flushes the block?
while (obj < end && obj->GetClass() != nullptr) {
callback(obj, arg);
obj = GetNextObject(obj);
}
pos += block_size;
}
}
bool BumpPointerSpace::IsEmpty() const {
return Size() == sizeof(BlockHeader);
}
uint64_t BumpPointerSpace::GetBytesAllocated() {
// Start out pre-determined amount (blocks which are not being allocated into).
uint64_t total = static_cast<uint64_t>(bytes_allocated_.Load());
Thread* self = Thread::Current();
MutexLock mu(self, *Locks::runtime_shutdown_lock_);
MutexLock mu2(self, *Locks::thread_list_lock_);
std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList();
MutexLock mu3(Thread::Current(), block_lock_);
// If we don't have any blocks, we don't have any thread local buffers. This check is required
// since there can exist multiple bump pointer spaces which exist at the same time.
if (num_blocks_ > 0) {
for (Thread* thread : thread_list) {
total += thread->thread_local_pos_ - thread->thread_local_start_;
}
}
return total;
}
uint64_t BumpPointerSpace::GetObjectsAllocated() {
// Start out pre-determined amount (blocks which are not being allocated into).
uint64_t total = static_cast<uint64_t>(objects_allocated_.Load());
Thread* self = Thread::Current();
MutexLock mu(self, *Locks::runtime_shutdown_lock_);
MutexLock mu2(self, *Locks::thread_list_lock_);
std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList();
MutexLock mu3(Thread::Current(), block_lock_);
// If we don't have any blocks, we don't have any thread local buffers. This check is required
// since there can exist multiple bump pointer spaces which exist at the same time.
if (num_blocks_ > 0) {
for (Thread* thread : thread_list) {
total += thread->thread_local_objects_;
}
}
return total;
}
void BumpPointerSpace::RevokeThreadLocalBuffersLocked(Thread* thread) {
objects_allocated_.FetchAndAdd(thread->thread_local_objects_);
bytes_allocated_.FetchAndAdd(thread->thread_local_pos_ - thread->thread_local_start_);
thread->SetTlab(nullptr, nullptr);
}
bool BumpPointerSpace::AllocNewTlab(Thread* self, size_t bytes) {
MutexLock mu(Thread::Current(), block_lock_);
RevokeThreadLocalBuffersLocked(self);
byte* start = AllocBlock(bytes);
if (start == nullptr) {
return false;
}
self->SetTlab(start, start + bytes);
return true;
}
} // namespace space
} // namespace gc
} // namespace art
|
