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// Copyright 2019 The Dawn Authors
//
// 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 "dawn/native/BuddyMemoryAllocator.h"
#include <utility>
#include "dawn/common/Math.h"
#include "dawn/native/ResourceHeapAllocator.h"
namespace dawn::native {
BuddyMemoryAllocator::BuddyMemoryAllocator(uint64_t maxSystemSize,
uint64_t memoryBlockSize,
ResourceHeapAllocator* heapAllocator)
: mMemoryBlockSize(memoryBlockSize),
mBuddyBlockAllocator(maxSystemSize),
mHeapAllocator(heapAllocator) {
ASSERT(memoryBlockSize <= maxSystemSize);
ASSERT(IsPowerOfTwo(mMemoryBlockSize));
ASSERT(maxSystemSize % mMemoryBlockSize == 0);
mTrackedSubAllocations.resize(maxSystemSize / mMemoryBlockSize);
}
BuddyMemoryAllocator::~BuddyMemoryAllocator() = default;
uint64_t BuddyMemoryAllocator::GetMemoryIndex(uint64_t offset) const {
ASSERT(offset != BuddyAllocator::kInvalidOffset);
return offset / mMemoryBlockSize;
}
ResultOrError<ResourceMemoryAllocation> BuddyMemoryAllocator::Allocate(uint64_t allocationSize,
uint64_t alignment) {
ResourceMemoryAllocation invalidAllocation = ResourceMemoryAllocation{};
if (allocationSize == 0) {
return std::move(invalidAllocation);
}
// Check the unaligned size to avoid overflowing NextPowerOfTwo.
if (allocationSize > mMemoryBlockSize) {
return std::move(invalidAllocation);
}
// Round allocation size to nearest power-of-two.
allocationSize = NextPowerOfTwo(allocationSize);
// Allocation cannot exceed the memory size.
if (allocationSize > mMemoryBlockSize) {
return std::move(invalidAllocation);
}
// Attempt to sub-allocate a block of the requested size.
const uint64_t blockOffset = mBuddyBlockAllocator.Allocate(allocationSize, alignment);
if (blockOffset == BuddyAllocator::kInvalidOffset) {
return std::move(invalidAllocation);
}
const uint64_t memoryIndex = GetMemoryIndex(blockOffset);
if (mTrackedSubAllocations[memoryIndex].refcount == 0) {
// Transfer ownership to this allocator
std::unique_ptr<ResourceHeapBase> memory;
DAWN_TRY_ASSIGN(memory, mHeapAllocator->AllocateResourceHeap(mMemoryBlockSize));
mTrackedSubAllocations[memoryIndex] = {/*refcount*/ 0, std::move(memory)};
}
mTrackedSubAllocations[memoryIndex].refcount++;
AllocationInfo info;
info.mBlockOffset = blockOffset;
info.mMethod = AllocationMethod::kSubAllocated;
// Allocation offset is always local to the memory.
const uint64_t memoryOffset = blockOffset % mMemoryBlockSize;
return ResourceMemoryAllocation{info, memoryOffset,
mTrackedSubAllocations[memoryIndex].mMemoryAllocation.get()};
}
void BuddyMemoryAllocator::Deallocate(const ResourceMemoryAllocation& allocation) {
const AllocationInfo info = allocation.GetInfo();
ASSERT(info.mMethod == AllocationMethod::kSubAllocated);
const uint64_t memoryIndex = GetMemoryIndex(info.mBlockOffset);
ASSERT(mTrackedSubAllocations[memoryIndex].refcount > 0);
mTrackedSubAllocations[memoryIndex].refcount--;
if (mTrackedSubAllocations[memoryIndex].refcount == 0) {
mHeapAllocator->DeallocateResourceHeap(
std::move(mTrackedSubAllocations[memoryIndex].mMemoryAllocation));
}
mBuddyBlockAllocator.Deallocate(info.mBlockOffset);
}
uint64_t BuddyMemoryAllocator::GetMemoryBlockSize() const {
return mMemoryBlockSize;
}
uint64_t BuddyMemoryAllocator::ComputeTotalNumOfHeapsForTesting() const {
uint64_t count = 0;
for (const TrackedSubAllocations& allocation : mTrackedSubAllocations) {
if (allocation.refcount > 0) {
count++;
}
}
return count;
}
} // namespace dawn::native