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/*
* Copyright (C) 2014 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 "scoped_arena_allocator.h"
#include "arena_allocator-inl.h"
#include "memory_tool.h"
namespace art {
static constexpr size_t kMemoryToolRedZoneBytes = 8;
ArenaStack::ArenaStack(ArenaPool* arena_pool)
: DebugStackRefCounter(),
stats_and_pool_(arena_pool),
bottom_arena_(nullptr),
top_arena_(nullptr),
top_ptr_(nullptr),
top_end_(nullptr) {
}
ArenaStack::~ArenaStack() {
DebugStackRefCounter::CheckNoRefs();
stats_and_pool_.pool->FreeArenaChain(bottom_arena_);
}
void ArenaStack::Reset() {
DebugStackRefCounter::CheckNoRefs();
stats_and_pool_.pool->FreeArenaChain(bottom_arena_);
bottom_arena_ = nullptr;
top_arena_ = nullptr;
top_ptr_ = nullptr;
top_end_ = nullptr;
}
MemStats ArenaStack::GetPeakStats() const {
DebugStackRefCounter::CheckNoRefs();
return MemStats("ArenaStack peak", PeakStats(), bottom_arena_);
}
uint8_t* ArenaStack::AllocateFromNextArena(size_t rounded_bytes) {
UpdateBytesAllocated();
size_t allocation_size = std::max(arena_allocator::kArenaDefaultSize, rounded_bytes);
if (UNLIKELY(top_arena_ == nullptr)) {
top_arena_ = bottom_arena_ = stats_and_pool_.pool->AllocArena(allocation_size);
top_arena_->next_ = nullptr;
} else if (top_arena_->next_ != nullptr && top_arena_->next_->Size() >= allocation_size) {
top_arena_ = top_arena_->next_;
} else {
Arena* tail = top_arena_->next_;
top_arena_->next_ = stats_and_pool_.pool->AllocArena(allocation_size);
top_arena_ = top_arena_->next_;
top_arena_->next_ = tail;
}
top_end_ = top_arena_->End();
// top_ptr_ shall be updated by ScopedArenaAllocator.
return top_arena_->Begin();
}
void ArenaStack::UpdatePeakStatsAndRestore(const ArenaAllocatorStats& restore_stats) {
if (PeakStats()->BytesAllocated() < CurrentStats()->BytesAllocated()) {
PeakStats()->Copy(*CurrentStats());
}
CurrentStats()->Copy(restore_stats);
}
void ArenaStack::UpdateBytesAllocated() {
if (top_arena_ != nullptr) {
// Update how many bytes we have allocated into the arena so that the arena pool knows how
// much memory to zero out. Though ScopedArenaAllocator doesn't guarantee the memory is
// zero-initialized, the Arena may be reused by ArenaAllocator which does guarantee this.
size_t allocated = static_cast<size_t>(top_ptr_ - top_arena_->Begin());
if (top_arena_->bytes_allocated_ < allocated) {
top_arena_->bytes_allocated_ = allocated;
}
}
}
void* ArenaStack::AllocWithMemoryTool(size_t bytes, ArenaAllocKind kind) {
// We mark all memory for a newly retrieved arena as inaccessible and then
// mark only the actually allocated memory as defined. That leaves red zones
// and padding between allocations marked as inaccessible.
size_t rounded_bytes = RoundUp(bytes + kMemoryToolRedZoneBytes, 8);
uint8_t* ptr = top_ptr_;
if (UNLIKELY(static_cast<size_t>(top_end_ - ptr) < rounded_bytes)) {
ptr = AllocateFromNextArena(rounded_bytes);
CHECK(ptr != nullptr) << "Failed to allocate memory";
MEMORY_TOOL_MAKE_NOACCESS(ptr, top_end_ - ptr);
}
CurrentStats()->RecordAlloc(bytes, kind);
top_ptr_ = ptr + rounded_bytes;
MEMORY_TOOL_MAKE_UNDEFINED(ptr, bytes);
return ptr;
}
size_t ArenaStack::ApproximatePeakBytes() {
UpdateBytesAllocated();
size_t sum = 0;
for (Arena* arena = bottom_arena_; arena != nullptr; arena = arena->next_) {
sum += arena->bytes_allocated_;
}
return sum;
}
ScopedArenaAllocator::ScopedArenaAllocator(ScopedArenaAllocator&& other) noexcept
: DebugStackReference(std::move(other)),
DebugStackRefCounter(),
ArenaAllocatorStats(other),
arena_stack_(other.arena_stack_),
mark_arena_(other.mark_arena_),
mark_ptr_(other.mark_ptr_),
mark_end_(other.mark_end_) {
other.DebugStackRefCounter::CheckNoRefs();
other.arena_stack_ = nullptr;
}
ScopedArenaAllocator::ScopedArenaAllocator(ArenaStack* arena_stack)
: DebugStackReference(arena_stack),
DebugStackRefCounter(),
ArenaAllocatorStats(*arena_stack->CurrentStats()),
arena_stack_(arena_stack),
mark_arena_(arena_stack->top_arena_),
mark_ptr_(arena_stack->top_ptr_),
mark_end_(arena_stack->top_end_) {
}
ScopedArenaAllocator::~ScopedArenaAllocator() {
if (arena_stack_ != nullptr) {
DoReset();
}
}
void ScopedArenaAllocator::Reset() {
DoReset();
// If this allocator was Create()d, we need to move the arena_stack_->top_ptr_ past *this.
if (mark_ptr_ == reinterpret_cast<uint8_t*>(this)) {
arena_stack_->top_ptr_ = mark_ptr_ + RoundUp(sizeof(ScopedArenaAllocator), 8);
}
}
void ScopedArenaAllocator::DoReset() {
DebugStackReference::CheckTop();
DebugStackRefCounter::CheckNoRefs();
arena_stack_->UpdatePeakStatsAndRestore(*this);
arena_stack_->UpdateBytesAllocated();
if (LIKELY(mark_arena_ != nullptr)) {
arena_stack_->top_arena_ = mark_arena_;
arena_stack_->top_ptr_ = mark_ptr_;
arena_stack_->top_end_ = mark_end_;
} else if (arena_stack_->bottom_arena_ != nullptr) {
mark_arena_ = arena_stack_->top_arena_ = arena_stack_->bottom_arena_;
mark_ptr_ = arena_stack_->top_ptr_ = mark_arena_->Begin();
mark_end_ = arena_stack_->top_end_ = mark_arena_->End();
}
}
size_t ScopedArenaAllocator::ApproximatePeakBytes() {
size_t subtract;
Arena* start;
if (LIKELY(mark_arena_ != nullptr)) {
start = mark_arena_;
size_t mark_free = static_cast<size_t>(mark_end_ - mark_ptr_);
DCHECK_GE(mark_arena_->bytes_allocated_, mark_arena_->size_ - mark_free);
subtract = mark_arena_->bytes_allocated_ - (mark_arena_->size_ - mark_free);
} else {
start = arena_stack_->bottom_arena_;
subtract = 0;
}
size_t sum = 0;
for (Arena* arena = start; arena != nullptr; arena = arena->next_) {
if (arena == arena_stack_->top_arena_) {
sum += static_cast<size_t>(arena_stack_->top_ptr_ - arena->Begin());
break;
} else {
sum += arena->bytes_allocated_;
}
}
return sum - subtract;
}
} // namespace art
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