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/*
* 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 "compiler_internals.h"
#include "dex_file-inl.h"
#include "arena_allocator.h"
#include "base/logging.h"
#include "base/mutex.h"
#include "thread-inl.h"
#include <memcheck/memcheck.h>
namespace art {
// Memmap is a bit slower than malloc according to my measurements.
static constexpr bool kUseMemMap = false;
static constexpr bool kUseMemSet = true && kUseMemMap;
static constexpr size_t kValgrindRedZoneBytes = 8;
constexpr size_t Arena::kDefaultSize;
static const char* alloc_names[ArenaAllocator::kNumAllocKinds] = {
"Misc ",
"BasicBlock ",
"LIR ",
"MIR ",
"DataFlow ",
"GrowList ",
"GrowBitMap ",
"Dalvik2SSA ",
"DebugInfo ",
"Successor ",
"RegAlloc ",
"Data ",
"Preds ",
};
Arena::Arena(size_t size)
: bytes_allocated_(0),
map_(nullptr),
next_(nullptr) {
if (kUseMemMap) {
std::string error_msg;
map_ = MemMap::MapAnonymous("dalvik-arena", NULL, size, PROT_READ | PROT_WRITE, false,
&error_msg);
CHECK(map_ != nullptr) << error_msg;
memory_ = map_->Begin();
size_ = map_->Size();
} else {
memory_ = reinterpret_cast<uint8_t*>(calloc(1, size));
size_ = size;
}
}
Arena::~Arena() {
if (kUseMemMap) {
delete map_;
} else {
free(reinterpret_cast<void*>(memory_));
}
}
void Arena::Reset() {
if (bytes_allocated_) {
if (kUseMemSet || !kUseMemMap) {
memset(Begin(), 0, bytes_allocated_);
} else {
madvise(Begin(), bytes_allocated_, MADV_DONTNEED);
}
bytes_allocated_ = 0;
}
}
ArenaPool::ArenaPool()
: lock_("Arena pool lock"),
free_arenas_(nullptr) {
}
ArenaPool::~ArenaPool() {
while (free_arenas_ != nullptr) {
auto* arena = free_arenas_;
free_arenas_ = free_arenas_->next_;
delete arena;
}
}
Arena* ArenaPool::AllocArena(size_t size) {
Thread* self = Thread::Current();
Arena* ret = nullptr;
{
MutexLock lock(self, lock_);
if (free_arenas_ != nullptr && LIKELY(free_arenas_->Size() >= size)) {
ret = free_arenas_;
free_arenas_ = free_arenas_->next_;
}
}
if (ret == nullptr) {
ret = new Arena(size);
}
ret->Reset();
return ret;
}
void ArenaPool::FreeArena(Arena* arena) {
Thread* self = Thread::Current();
if (UNLIKELY(RUNNING_ON_VALGRIND)) {
VALGRIND_MAKE_MEM_UNDEFINED(arena->memory_, arena->bytes_allocated_);
}
{
MutexLock lock(self, lock_);
arena->next_ = free_arenas_;
free_arenas_ = arena;
}
}
size_t ArenaAllocator::BytesAllocated() const {
size_t total = 0;
for (int i = 0; i < kNumAllocKinds; i++) {
total += alloc_stats_[i];
}
return total;
}
ArenaAllocator::ArenaAllocator(ArenaPool* pool)
: pool_(pool),
begin_(nullptr),
end_(nullptr),
ptr_(nullptr),
arena_head_(nullptr),
num_allocations_(0),
running_on_valgrind_(RUNNING_ON_VALGRIND) {
memset(&alloc_stats_[0], 0, sizeof(alloc_stats_));
}
void ArenaAllocator::UpdateBytesAllocated() {
if (arena_head_ != nullptr) {
// Update how many bytes we have allocated into the arena so that the arena pool knows how
// much memory to zero out.
arena_head_->bytes_allocated_ = ptr_ - begin_;
}
}
void* ArenaAllocator::AllocValgrind(size_t bytes, ArenaAllocKind kind) {
size_t rounded_bytes = (bytes + 3 + kValgrindRedZoneBytes) & ~3;
if (UNLIKELY(ptr_ + rounded_bytes > end_)) {
// Obtain a new block.
ObtainNewArenaForAllocation(rounded_bytes);
if (UNLIKELY(ptr_ == nullptr)) {
return nullptr;
}
}
if (kCountAllocations) {
alloc_stats_[kind] += rounded_bytes;
++num_allocations_;
}
uint8_t* ret = ptr_;
ptr_ += rounded_bytes;
// Check that the memory is already zeroed out.
for (uint8_t* ptr = ret; ptr < ptr_; ++ptr) {
CHECK_EQ(*ptr, 0U);
}
VALGRIND_MAKE_MEM_NOACCESS(ret + bytes, rounded_bytes - bytes);
return ret;
}
ArenaAllocator::~ArenaAllocator() {
// Reclaim all the arenas by giving them back to the thread pool.
UpdateBytesAllocated();
while (arena_head_ != nullptr) {
Arena* arena = arena_head_;
arena_head_ = arena_head_->next_;
pool_->FreeArena(arena);
}
}
void ArenaAllocator::ObtainNewArenaForAllocation(size_t allocation_size) {
UpdateBytesAllocated();
Arena* new_arena = pool_->AllocArena(std::max(Arena::kDefaultSize, allocation_size));
new_arena->next_ = arena_head_;
arena_head_ = new_arena;
// Update our internal data structures.
ptr_ = begin_ = new_arena->Begin();
end_ = new_arena->End();
}
// Dump memory usage stats.
void ArenaAllocator::DumpMemStats(std::ostream& os) const {
size_t malloc_bytes = 0;
// Start out with how many lost bytes we have in the arena we are currently allocating into.
size_t lost_bytes(end_ - ptr_);
size_t num_arenas = 0;
for (Arena* arena = arena_head_; arena != nullptr; arena = arena->next_) {
malloc_bytes += arena->Size();
if (arena != arena_head_) {
lost_bytes += arena->RemainingSpace();
}
++num_arenas;
}
const size_t bytes_allocated = BytesAllocated();
os << " MEM: used: " << bytes_allocated << ", allocated: " << malloc_bytes
<< ", lost: " << lost_bytes << "\n";
if (num_allocations_ != 0) {
os << "Number of arenas allocated: " << num_arenas << ", Number of allocations: "
<< num_allocations_ << ", avg size: " << bytes_allocated / num_allocations_ << "\n";
}
os << "===== Allocation by kind\n";
for (int i = 0; i < kNumAllocKinds; i++) {
os << alloc_names[i] << std::setw(10) << alloc_stats_[i] << "\n";
}
}
} // namespace art
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