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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.
#ifndef SRC_DAWN_NATIVE_BUDDYMEMORYALLOCATOR_H_
#define SRC_DAWN_NATIVE_BUDDYMEMORYALLOCATOR_H_
#include <memory>
#include <vector>
#include "dawn/native/BuddyAllocator.h"
#include "dawn/native/Error.h"
#include "dawn/native/ResourceMemoryAllocation.h"
namespace dawn::native {
class ResourceHeapAllocator;
// BuddyMemoryAllocator uses the buddy allocator to sub-allocate blocks of device
// memory created by MemoryAllocator clients. It creates a very large buddy system
// where backing device memory blocks equal a specified level in the system.
//
// Upon sub-allocating, the offset gets mapped to device memory by computing the corresponding
// memory index and should the memory not exist, it is created. If two sub-allocations share the
// same memory index, the memory refcount is incremented to ensure de-allocating one doesn't
// release the other prematurely.
//
// The MemoryAllocator should return ResourceHeaps that are all compatible with each other.
// It should also outlive all the resources that are in the buddy allocator.
class BuddyMemoryAllocator {
public:
BuddyMemoryAllocator(uint64_t maxSystemSize,
uint64_t memoryBlockSize,
ResourceHeapAllocator* heapAllocator);
~BuddyMemoryAllocator();
ResultOrError<ResourceMemoryAllocation> Allocate(uint64_t allocationSize, uint64_t alignment);
void Deallocate(const ResourceMemoryAllocation& allocation);
uint64_t GetMemoryBlockSize() const;
// For testing purposes.
uint64_t ComputeTotalNumOfHeapsForTesting() const;
private:
uint64_t GetMemoryIndex(uint64_t offset) const;
uint64_t mMemoryBlockSize = 0;
BuddyAllocator mBuddyBlockAllocator;
ResourceHeapAllocator* mHeapAllocator;
struct TrackedSubAllocations {
size_t refcount = 0;
std::unique_ptr<ResourceHeapBase> mMemoryAllocation;
};
std::vector<TrackedSubAllocations> mTrackedSubAllocations;
};
} // namespace dawn::native
#endif // SRC_DAWN_NATIVE_BUDDYMEMORYALLOCATOR_H_