src/dawn_native/d3d12/ResourceAllocatorManagerD3D12.cpp - dawn - Git at Google

 // 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/d3d12/ResourceAllocatorManagerD3D12.h"

 #include "dawn_native/d3d12/D3D12Error.h"
 #include "dawn_native/d3d12/DeviceD3D12.h"
 #include "dawn_native/d3d12/HeapAllocatorD3D12.h"
 #include "dawn_native/d3d12/HeapD3D12.h"
 #include "dawn_native/d3d12/ResidencyManagerD3D12.h"
 #include "dawn_native/d3d12/UtilsD3D12.h"

 namespace dawn_native { namespace d3d12 {
     namespace {
         MemorySegment GetMemorySegment(Device* device, D3D12_HEAP_TYPE heapType) {
             if (device->GetDeviceInfo().isUMA) {
                 return MemorySegment::Local;
             }

             D3D12_HEAP_PROPERTIES heapProperties =
                 device->GetD3D12Device()->GetCustomHeapProperties(0, heapType);

             if (heapProperties.MemoryPoolPreference == D3D12_MEMORY_POOL_L1) {
                 return MemorySegment::Local;
             }

             return MemorySegment::NonLocal;
         }

         D3D12_HEAP_TYPE GetD3D12HeapType(ResourceHeapKind resourceHeapKind) {
             switch (resourceHeapKind) {
                 case Readback_OnlyBuffers:
                 case Readback_AllBuffersAndTextures:
                     return D3D12_HEAP_TYPE_READBACK;
                 case Default_AllBuffersAndTextures:
                 case Default_OnlyBuffers:
                 case Default_OnlyNonRenderableOrDepthTextures:
                 case Default_OnlyRenderableOrDepthTextures:
                     return D3D12_HEAP_TYPE_DEFAULT;
                 case Upload_OnlyBuffers:
                 case Upload_AllBuffersAndTextures:
                     return D3D12_HEAP_TYPE_UPLOAD;
                 case EnumCount:
                     UNREACHABLE();
             }
         }

         D3D12_HEAP_FLAGS GetD3D12HeapFlags(ResourceHeapKind resourceHeapKind) {
             switch (resourceHeapKind) {
                 case Default_AllBuffersAndTextures:
                 case Readback_AllBuffersAndTextures:
                 case Upload_AllBuffersAndTextures:
                     return D3D12_HEAP_FLAG_ALLOW_ALL_BUFFERS_AND_TEXTURES;
                 case Default_OnlyBuffers:
                 case Readback_OnlyBuffers:
                 case Upload_OnlyBuffers:
                     return D3D12_HEAP_FLAG_ALLOW_ONLY_BUFFERS;
                 case Default_OnlyNonRenderableOrDepthTextures:
                     return D3D12_HEAP_FLAG_ALLOW_ONLY_NON_RT_DS_TEXTURES;
                 case Default_OnlyRenderableOrDepthTextures:
                     return D3D12_HEAP_FLAG_ALLOW_ONLY_RT_DS_TEXTURES;
                 case EnumCount:
                     UNREACHABLE();
             }
         }

         ResourceHeapKind GetResourceHeapKind(D3D12_RESOURCE_DIMENSION dimension,
                                              D3D12_HEAP_TYPE heapType,
                                              D3D12_RESOURCE_FLAGS flags,
                                              uint32_t resourceHeapTier) {
             if (resourceHeapTier >= 2) {
                 switch (heapType) {
                     case D3D12_HEAP_TYPE_UPLOAD:
                         return Upload_AllBuffersAndTextures;
                     case D3D12_HEAP_TYPE_DEFAULT:
                         return Default_AllBuffersAndTextures;
                     case D3D12_HEAP_TYPE_READBACK:
                         return Readback_AllBuffersAndTextures;
                     default:
                         UNREACHABLE();
                 }
             }

             switch (dimension) {
                 case D3D12_RESOURCE_DIMENSION_BUFFER: {
                     switch (heapType) {
                         case D3D12_HEAP_TYPE_UPLOAD:
                             return Upload_OnlyBuffers;
                         case D3D12_HEAP_TYPE_DEFAULT:
                             return Default_OnlyBuffers;
                         case D3D12_HEAP_TYPE_READBACK:
                             return Readback_OnlyBuffers;
                         default:
                             UNREACHABLE();
                     }
                     break;
                 }
                 case D3D12_RESOURCE_DIMENSION_TEXTURE1D:
                 case D3D12_RESOURCE_DIMENSION_TEXTURE2D:
                 case D3D12_RESOURCE_DIMENSION_TEXTURE3D: {
                     switch (heapType) {
                         case D3D12_HEAP_TYPE_DEFAULT: {
                             if ((flags & D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL) ||
                                 (flags & D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET)) {
                                 return Default_OnlyRenderableOrDepthTextures;
                             }
                             return Default_OnlyNonRenderableOrDepthTextures;
                         }

                         default:
                             UNREACHABLE();
                     }
                     break;
                 }
                 default:
                     UNREACHABLE();
             }
         }

         uint64_t GetResourcePlacementAlignment(ResourceHeapKind resourceHeapKind,
                                                uint32_t sampleCount,
                                                uint64_t requestedAlignment) {
             switch (resourceHeapKind) {
                 // Small resources can take advantage of smaller alignments. For example,
                 // if the most detailed mip can fit under 64KB, 4KB alignments can be used.
                 // Must be non-depth or without render-target to use small resource alignment.
                 // This also applies to MSAA textures (4MB => 64KB).
                 //
                 // Note: Only known to be used for small textures; however, MSDN suggests
                 // it could be extended for more cases. If so, this could default to always
                 // attempt small resource placement.
                 // https://docs.microsoft.com/en-us/windows/win32/api/d3d12/ns-d3d12-d3d12_resource_desc
                 case Default_OnlyNonRenderableOrDepthTextures:
                     return (sampleCount > 1) ? D3D12_SMALL_MSAA_RESOURCE_PLACEMENT_ALIGNMENT
                                              : D3D12_SMALL_RESOURCE_PLACEMENT_ALIGNMENT;
                 default:
                     return requestedAlignment;
             }
         }

         bool IsClearValueOptimizable(const D3D12_RESOURCE_DESC& resourceDescriptor) {
             // Optimized clear color cannot be set on buffers, non-render-target/depth-stencil
             // textures, or typeless resources
             // https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12device-createcommittedresource
             // https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12device-createplacedresource
             return !IsTypeless(resourceDescriptor.Format) &&
                    resourceDescriptor.Dimension != D3D12_RESOURCE_DIMENSION_BUFFER &&
                    (resourceDescriptor.Flags & (D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET |
                                                 D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL)) != 0;
         }

     }  // namespace

     ResourceAllocatorManager::ResourceAllocatorManager(Device* device) : mDevice(device) {
         mResourceHeapTier = (mDevice->IsToggleEnabled(Toggle::UseD3D12ResourceHeapTier2))
                                 ? mDevice->GetDeviceInfo().resourceHeapTier
                                 : 1;

         for (uint32_t i = 0; i < ResourceHeapKind::EnumCount; i++) {
             const ResourceHeapKind resourceHeapKind = static_cast<ResourceHeapKind>(i);
             mHeapAllocators[i] = std::make_unique<HeapAllocator>(
                 mDevice, GetD3D12HeapType(resourceHeapKind), GetD3D12HeapFlags(resourceHeapKind),
                 GetMemorySegment(device, GetD3D12HeapType(resourceHeapKind)));
             mPooledHeapAllocators[i] =
                 std::make_unique<PooledResourceMemoryAllocator>(mHeapAllocators[i].get());
             mSubAllocatedResourceAllocators[i] = std::make_unique<BuddyMemoryAllocator>(
                 kMaxHeapSize, kMinHeapSize, mPooledHeapAllocators[i].get());
         }
     }

     ResultOrError<ResourceHeapAllocation> ResourceAllocatorManager::AllocateMemory(
         D3D12_HEAP_TYPE heapType,
         const D3D12_RESOURCE_DESC& resourceDescriptor,
         D3D12_RESOURCE_STATES initialUsage) {
         // In order to suppress a warning in the D3D12 debug layer, we need to specify an
         // optimized clear value. As there are no negative consequences when picking a mismatched
         // clear value, we use zero as the optimized clear value. This also enables fast clears on
         // some architectures.
         D3D12_CLEAR_VALUE zero{};
         D3D12_CLEAR_VALUE* optimizedClearValue = nullptr;
         if (IsClearValueOptimizable(resourceDescriptor)) {
             zero.Format = resourceDescriptor.Format;
             optimizedClearValue = &zero;
         }

         // TODO(crbug.com/dawn/849): Conditionally disable sub-allocation.
         // For very large resources, there is no benefit to suballocate.
         // For very small resources, it is inefficent to suballocate given the min. heap
         // size could be much larger then the resource allocation.
         // Attempt to satisfy the request using sub-allocation (placed resource in a heap).
         ResourceHeapAllocation subAllocation;
         DAWN_TRY_ASSIGN(subAllocation, CreatePlacedResource(heapType, resourceDescriptor,
                                                             optimizedClearValue, initialUsage));
         if (subAllocation.GetInfo().mMethod != AllocationMethod::kInvalid) {
             return std::move(subAllocation);
         }

         // If sub-allocation fails, fall-back to direct allocation (committed resource).
         ResourceHeapAllocation directAllocation;
         DAWN_TRY_ASSIGN(directAllocation,
                         CreateCommittedResource(heapType, resourceDescriptor, optimizedClearValue,
                                                 initialUsage));
         if (directAllocation.GetInfo().mMethod != AllocationMethod::kInvalid) {
             return std::move(directAllocation);
         }

         // If direct allocation fails, the system is probably out of memory.
         return DAWN_OUT_OF_MEMORY_ERROR("Allocation failed");
     }

     void ResourceAllocatorManager::Tick(ExecutionSerial completedSerial) {
         for (ResourceHeapAllocation& allocation :
              mAllocationsToDelete.IterateUpTo(completedSerial)) {
             if (allocation.GetInfo().mMethod == AllocationMethod::kSubAllocated) {
                 FreeMemory(allocation);
             }
         }
         mAllocationsToDelete.ClearUpTo(completedSerial);
     }

     void ResourceAllocatorManager::DeallocateMemory(ResourceHeapAllocation& allocation) {
         if (allocation.GetInfo().mMethod == AllocationMethod::kInvalid) {
             return;
         }

         mAllocationsToDelete.Enqueue(allocation, mDevice->GetPendingCommandSerial());

         // Directly allocated ResourceHeapAllocations are created with a heap object that must be
         // manually deleted upon deallocation. See ResourceAllocatorManager::CreateCommittedResource
         // for more information.
         if (allocation.GetInfo().mMethod == AllocationMethod::kDirect) {
             delete allocation.GetResourceHeap();
         }

         // Invalidate the allocation immediately in case one accidentally
         // calls DeallocateMemory again using the same allocation.
         allocation.Invalidate();

         ASSERT(allocation.GetD3D12Resource() == nullptr);
     }

     void ResourceAllocatorManager::FreeMemory(ResourceHeapAllocation& allocation) {
         ASSERT(allocation.GetInfo().mMethod == AllocationMethod::kSubAllocated);

         D3D12_HEAP_PROPERTIES heapProp;
         allocation.GetD3D12Resource()->GetHeapProperties(&heapProp, nullptr);

         const D3D12_RESOURCE_DESC resourceDescriptor = allocation.GetD3D12Resource()->GetDesc();

         const size_t resourceHeapKindIndex =
             GetResourceHeapKind(resourceDescriptor.Dimension, heapProp.Type,
                                 resourceDescriptor.Flags, mResourceHeapTier);

         mSubAllocatedResourceAllocators[resourceHeapKindIndex]->Deallocate(allocation);
     }

     ResultOrError<ResourceHeapAllocation> ResourceAllocatorManager::CreatePlacedResource(
         D3D12_HEAP_TYPE heapType,
         const D3D12_RESOURCE_DESC& requestedResourceDescriptor,
         const D3D12_CLEAR_VALUE* optimizedClearValue,
         D3D12_RESOURCE_STATES initialUsage) {
         const ResourceHeapKind resourceHeapKind =
             GetResourceHeapKind(requestedResourceDescriptor.Dimension, heapType,
                                 requestedResourceDescriptor.Flags, mResourceHeapTier);

         D3D12_RESOURCE_DESC resourceDescriptor = requestedResourceDescriptor;
         resourceDescriptor.Alignment = GetResourcePlacementAlignment(
             resourceHeapKind, requestedResourceDescriptor.SampleDesc.Count,
             requestedResourceDescriptor.Alignment);

         // TODO(bryan.bernhart): Figure out how to compute the alignment without calling this
         // twice.
         D3D12_RESOURCE_ALLOCATION_INFO resourceInfo =
             mDevice->GetD3D12Device()->GetResourceAllocationInfo(0, 1, &resourceDescriptor);

         // If the requested resource alignment was rejected, let D3D tell us what the
         // required alignment is for this resource.
         if (resourceDescriptor.Alignment != 0 &&
             resourceDescriptor.Alignment != resourceInfo.Alignment) {
             resourceDescriptor.Alignment = 0;
             resourceInfo =
                 mDevice->GetD3D12Device()->GetResourceAllocationInfo(0, 1, &resourceDescriptor);
         }

         // If d3d tells us the resource size is invalid, treat the error as OOM.
         // Otherwise, creating the resource could cause a device loss (too large).
         // This is because NextPowerOfTwo(UINT64_MAX) overflows and proceeds to
         // incorrectly allocate a mismatched size.
         if (resourceInfo.SizeInBytes == 0 ||
             resourceInfo.SizeInBytes == std::numeric_limits<uint64_t>::max()) {
             return DAWN_OUT_OF_MEMORY_ERROR("Resource allocation size was invalid.");
         }

         BuddyMemoryAllocator* allocator =
             mSubAllocatedResourceAllocators[static_cast<size_t>(resourceHeapKind)].get();

         ResourceMemoryAllocation allocation;
         DAWN_TRY_ASSIGN(allocation,
                         allocator->Allocate(resourceInfo.SizeInBytes, resourceInfo.Alignment));
         if (allocation.GetInfo().mMethod == AllocationMethod::kInvalid) {
             return ResourceHeapAllocation{};  // invalid
         }

         Heap* heap = ToBackend(allocation.GetResourceHeap());

         // Before calling CreatePlacedResource, we must ensure the target heap is resident.
         // CreatePlacedResource will fail if it is not.
         DAWN_TRY(mDevice->GetResidencyManager()->LockAllocation(heap));

         // With placed resources, a single heap can be reused.
         // The resource placed at an offset is only reclaimed
         // upon Tick or after the last command list using the resource has completed
         // on the GPU. This means the same physical memory is not reused
         // within the same command-list and does not require additional synchronization (aliasing
         // barrier).
         // https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12device-createplacedresource
         ComPtr<ID3D12Resource> placedResource;
         DAWN_TRY(CheckOutOfMemoryHRESULT(
             mDevice->GetD3D12Device()->CreatePlacedResource(
                 heap->GetD3D12Heap(), allocation.GetOffset(), &resourceDescriptor, initialUsage,
                 optimizedClearValue, IID_PPV_ARGS(&placedResource)),
             "ID3D12Device::CreatePlacedResource"));

         // After CreatePlacedResource has finished, the heap can be unlocked from residency. This
         // will insert it into the residency LRU.
         mDevice->GetResidencyManager()->UnlockAllocation(heap);

         return ResourceHeapAllocation{allocation.GetInfo(), allocation.GetOffset(),
                                       std::move(placedResource), heap};
     }

     ResultOrError<ResourceHeapAllocation> ResourceAllocatorManager::CreateCommittedResource(
         D3D12_HEAP_TYPE heapType,
         const D3D12_RESOURCE_DESC& resourceDescriptor,
         const D3D12_CLEAR_VALUE* optimizedClearValue,
         D3D12_RESOURCE_STATES initialUsage) {
         D3D12_HEAP_PROPERTIES heapProperties;
         heapProperties.Type = heapType;
         heapProperties.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
         heapProperties.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
         heapProperties.CreationNodeMask = 0;
         heapProperties.VisibleNodeMask = 0;

         // If d3d tells us the resource size is invalid, treat the error as OOM.
         // Otherwise, creating the resource could cause a device loss (too large).
         // This is because NextPowerOfTwo(UINT64_MAX) overflows and proceeds to
         // incorrectly allocate a mismatched size.
         D3D12_RESOURCE_ALLOCATION_INFO resourceInfo =
             mDevice->GetD3D12Device()->GetResourceAllocationInfo(0, 1, &resourceDescriptor);
         if (resourceInfo.SizeInBytes == 0 ||
             resourceInfo.SizeInBytes == std::numeric_limits<uint64_t>::max()) {
             return DAWN_OUT_OF_MEMORY_ERROR("Resource allocation size was invalid.");
         }

         if (resourceInfo.SizeInBytes > kMaxHeapSize) {
             return ResourceHeapAllocation{};  // Invalid
         }

         // CreateCommittedResource will implicitly make the created resource resident. We must
         // ensure enough free memory exists before allocating to avoid an out-of-memory error when
         // overcommitted.
         DAWN_TRY(mDevice->GetResidencyManager()->EnsureCanAllocate(
             resourceInfo.SizeInBytes, GetMemorySegment(mDevice, heapType)));

         // Note: Heap flags are inferred by the resource descriptor and do not need to be explicitly
         // provided to CreateCommittedResource.
         ComPtr<ID3D12Resource> committedResource;
         DAWN_TRY(CheckOutOfMemoryHRESULT(
             mDevice->GetD3D12Device()->CreateCommittedResource(
                 &heapProperties, D3D12_HEAP_FLAG_NONE, &resourceDescriptor, initialUsage,
                 optimizedClearValue, IID_PPV_ARGS(&committedResource)),
             "ID3D12Device::CreateCommittedResource"));

         // When using CreateCommittedResource, D3D12 creates an implicit heap that contains the
         // resource allocation. Because Dawn's memory residency management occurs at the resource
         // heap granularity, every directly allocated ResourceHeapAllocation also stores a Heap
         // object. This object is created manually, and must be deleted manually upon deallocation
         // of the committed resource.
         Heap* heap = new Heap(committedResource, GetMemorySegment(mDevice, heapType),
                               resourceInfo.SizeInBytes);

         // Calling CreateCommittedResource implicitly calls MakeResident on the resource. We must
         // track this to avoid calling MakeResident a second time.
         mDevice->GetResidencyManager()->TrackResidentAllocation(heap);

         AllocationInfo info;
         info.mMethod = AllocationMethod::kDirect;

         return ResourceHeapAllocation{info,
                                       /*offset*/ 0, std::move(committedResource), heap};
     }

     void ResourceAllocatorManager::DestroyPool() {
         for (auto& alloc : mPooledHeapAllocators) {
             alloc->DestroyPool();
         }
     }

 }}  // namespace dawn_native::d3d12
	// 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/d3d12/ResourceAllocatorManagerD3D12.h"

	#include "dawn_native/d3d12/D3D12Error.h"
	#include "dawn_native/d3d12/DeviceD3D12.h"
	#include "dawn_native/d3d12/HeapAllocatorD3D12.h"
	#include "dawn_native/d3d12/HeapD3D12.h"
	#include "dawn_native/d3d12/ResidencyManagerD3D12.h"
	#include "dawn_native/d3d12/UtilsD3D12.h"

	namespace dawn_native { namespace d3d12 {
	namespace {
	MemorySegment GetMemorySegment(Device* device, D3D12_HEAP_TYPE heapType) {
	if (device->GetDeviceInfo().isUMA) {
	return MemorySegment::Local;
	}

	D3D12_HEAP_PROPERTIES heapProperties =
	device->GetD3D12Device()->GetCustomHeapProperties(0, heapType);

	if (heapProperties.MemoryPoolPreference == D3D12_MEMORY_POOL_L1) {
	return MemorySegment::Local;
	}

	return MemorySegment::NonLocal;
	}

	D3D12_HEAP_TYPE GetD3D12HeapType(ResourceHeapKind resourceHeapKind) {
	switch (resourceHeapKind) {
	case Readback_OnlyBuffers:
	case Readback_AllBuffersAndTextures:
	return D3D12_HEAP_TYPE_READBACK;
	case Default_AllBuffersAndTextures:
	case Default_OnlyBuffers:
	case Default_OnlyNonRenderableOrDepthTextures:
	case Default_OnlyRenderableOrDepthTextures:
	return D3D12_HEAP_TYPE_DEFAULT;
	case Upload_OnlyBuffers:
	case Upload_AllBuffersAndTextures:
	return D3D12_HEAP_TYPE_UPLOAD;
	case EnumCount:
	UNREACHABLE();
	}
	}

	D3D12_HEAP_FLAGS GetD3D12HeapFlags(ResourceHeapKind resourceHeapKind) {
	switch (resourceHeapKind) {
	case Default_AllBuffersAndTextures:
	case Readback_AllBuffersAndTextures:
	case Upload_AllBuffersAndTextures:
	return D3D12_HEAP_FLAG_ALLOW_ALL_BUFFERS_AND_TEXTURES;
	case Default_OnlyBuffers:
	case Readback_OnlyBuffers:
	case Upload_OnlyBuffers:
	return D3D12_HEAP_FLAG_ALLOW_ONLY_BUFFERS;
	case Default_OnlyNonRenderableOrDepthTextures:
	return D3D12_HEAP_FLAG_ALLOW_ONLY_NON_RT_DS_TEXTURES;
	case Default_OnlyRenderableOrDepthTextures:
	return D3D12_HEAP_FLAG_ALLOW_ONLY_RT_DS_TEXTURES;
	case EnumCount:
	UNREACHABLE();
	}
	}

	ResourceHeapKind GetResourceHeapKind(D3D12_RESOURCE_DIMENSION dimension,
	D3D12_HEAP_TYPE heapType,
	D3D12_RESOURCE_FLAGS flags,
	uint32_t resourceHeapTier) {
	if (resourceHeapTier >= 2) {
	switch (heapType) {
	case D3D12_HEAP_TYPE_UPLOAD:
	return Upload_AllBuffersAndTextures;
	case D3D12_HEAP_TYPE_DEFAULT:
	return Default_AllBuffersAndTextures;
	case D3D12_HEAP_TYPE_READBACK:
	return Readback_AllBuffersAndTextures;
	default:
	UNREACHABLE();
	}
	}

	switch (dimension) {
	case D3D12_RESOURCE_DIMENSION_BUFFER: {
	switch (heapType) {
	case D3D12_HEAP_TYPE_UPLOAD:
	return Upload_OnlyBuffers;
	case D3D12_HEAP_TYPE_DEFAULT:
	return Default_OnlyBuffers;
	case D3D12_HEAP_TYPE_READBACK:
	return Readback_OnlyBuffers;
	default:
	UNREACHABLE();
	}
	break;
	}
	case D3D12_RESOURCE_DIMENSION_TEXTURE1D:
	case D3D12_RESOURCE_DIMENSION_TEXTURE2D:
	case D3D12_RESOURCE_DIMENSION_TEXTURE3D: {
	switch (heapType) {
	case D3D12_HEAP_TYPE_DEFAULT: {
	if ((flags & D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL) \|\|
	(flags & D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET)) {
	return Default_OnlyRenderableOrDepthTextures;
	}
	return Default_OnlyNonRenderableOrDepthTextures;
	}

	default:
	UNREACHABLE();
	}
	break;
	}
	default:
	UNREACHABLE();
	}
	}

	uint64_t GetResourcePlacementAlignment(ResourceHeapKind resourceHeapKind,
	uint32_t sampleCount,
	uint64_t requestedAlignment) {
	switch (resourceHeapKind) {
	// Small resources can take advantage of smaller alignments. For example,
	// if the most detailed mip can fit under 64KB, 4KB alignments can be used.
	// Must be non-depth or without render-target to use small resource alignment.
	// This also applies to MSAA textures (4MB => 64KB).
	//
	// Note: Only known to be used for small textures; however, MSDN suggests
	// it could be extended for more cases. If so, this could default to always
	// attempt small resource placement.
	// https://docs.microsoft.com/en-us/windows/win32/api/d3d12/ns-d3d12-d3d12_resource_desc
	case Default_OnlyNonRenderableOrDepthTextures:
	return (sampleCount > 1) ? D3D12_SMALL_MSAA_RESOURCE_PLACEMENT_ALIGNMENT
	: D3D12_SMALL_RESOURCE_PLACEMENT_ALIGNMENT;
	default:
	return requestedAlignment;
	}
	}

	bool IsClearValueOptimizable(const D3D12_RESOURCE_DESC& resourceDescriptor) {
	// Optimized clear color cannot be set on buffers, non-render-target/depth-stencil
	// textures, or typeless resources
	// https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12device-createcommittedresource
	// https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12device-createplacedresource
	return !IsTypeless(resourceDescriptor.Format) &&
	resourceDescriptor.Dimension != D3D12_RESOURCE_DIMENSION_BUFFER &&
	(resourceDescriptor.Flags & (D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET \|
	D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL)) != 0;
	}

	} // namespace

	ResourceAllocatorManager::ResourceAllocatorManager(Device* device) : mDevice(device) {
	mResourceHeapTier = (mDevice->IsToggleEnabled(Toggle::UseD3D12ResourceHeapTier2))
	? mDevice->GetDeviceInfo().resourceHeapTier
	: 1;

	for (uint32_t i = 0; i < ResourceHeapKind::EnumCount; i++) {
	const ResourceHeapKind resourceHeapKind = static_cast<ResourceHeapKind>(i);
	mHeapAllocators[i] = std::make_unique<HeapAllocator>(
	mDevice, GetD3D12HeapType(resourceHeapKind), GetD3D12HeapFlags(resourceHeapKind),
	GetMemorySegment(device, GetD3D12HeapType(resourceHeapKind)));
	mPooledHeapAllocators[i] =
	std::make_unique<PooledResourceMemoryAllocator>(mHeapAllocators[i].get());
	mSubAllocatedResourceAllocators[i] = std::make_unique<BuddyMemoryAllocator>(
	kMaxHeapSize, kMinHeapSize, mPooledHeapAllocators[i].get());
	}
	}

	ResultOrError<ResourceHeapAllocation> ResourceAllocatorManager::AllocateMemory(
	D3D12_HEAP_TYPE heapType,
	const D3D12_RESOURCE_DESC& resourceDescriptor,
	D3D12_RESOURCE_STATES initialUsage) {
	// In order to suppress a warning in the D3D12 debug layer, we need to specify an
	// optimized clear value. As there are no negative consequences when picking a mismatched
	// clear value, we use zero as the optimized clear value. This also enables fast clears on
	// some architectures.
	D3D12_CLEAR_VALUE zero{};
	D3D12_CLEAR_VALUE* optimizedClearValue = nullptr;
	if (IsClearValueOptimizable(resourceDescriptor)) {
	zero.Format = resourceDescriptor.Format;
	optimizedClearValue = &zero;
	}

	// TODO(crbug.com/dawn/849): Conditionally disable sub-allocation.
	// For very large resources, there is no benefit to suballocate.
	// For very small resources, it is inefficent to suballocate given the min. heap
	// size could be much larger then the resource allocation.
	// Attempt to satisfy the request using sub-allocation (placed resource in a heap).
	ResourceHeapAllocation subAllocation;
	DAWN_TRY_ASSIGN(subAllocation, CreatePlacedResource(heapType, resourceDescriptor,
	optimizedClearValue, initialUsage));
	if (subAllocation.GetInfo().mMethod != AllocationMethod::kInvalid) {
	return std::move(subAllocation);
	}

	// If sub-allocation fails, fall-back to direct allocation (committed resource).
	ResourceHeapAllocation directAllocation;
	DAWN_TRY_ASSIGN(directAllocation,
	CreateCommittedResource(heapType, resourceDescriptor, optimizedClearValue,
	initialUsage));
	if (directAllocation.GetInfo().mMethod != AllocationMethod::kInvalid) {
	return std::move(directAllocation);
	}

	// If direct allocation fails, the system is probably out of memory.
	return DAWN_OUT_OF_MEMORY_ERROR("Allocation failed");
	}

	void ResourceAllocatorManager::Tick(ExecutionSerial completedSerial) {
	for (ResourceHeapAllocation& allocation :
	mAllocationsToDelete.IterateUpTo(completedSerial)) {
	if (allocation.GetInfo().mMethod == AllocationMethod::kSubAllocated) {
	FreeMemory(allocation);
	}
	}
	mAllocationsToDelete.ClearUpTo(completedSerial);
	}

	void ResourceAllocatorManager::DeallocateMemory(ResourceHeapAllocation& allocation) {
	if (allocation.GetInfo().mMethod == AllocationMethod::kInvalid) {
	return;
	}

	mAllocationsToDelete.Enqueue(allocation, mDevice->GetPendingCommandSerial());

	// Directly allocated ResourceHeapAllocations are created with a heap object that must be
	// manually deleted upon deallocation. See ResourceAllocatorManager::CreateCommittedResource
	// for more information.
	if (allocation.GetInfo().mMethod == AllocationMethod::kDirect) {
	delete allocation.GetResourceHeap();
	}

	// Invalidate the allocation immediately in case one accidentally
	// calls DeallocateMemory again using the same allocation.
	allocation.Invalidate();

	ASSERT(allocation.GetD3D12Resource() == nullptr);
	}

	void ResourceAllocatorManager::FreeMemory(ResourceHeapAllocation& allocation) {
	ASSERT(allocation.GetInfo().mMethod == AllocationMethod::kSubAllocated);

	D3D12_HEAP_PROPERTIES heapProp;
	allocation.GetD3D12Resource()->GetHeapProperties(&heapProp, nullptr);

	const D3D12_RESOURCE_DESC resourceDescriptor = allocation.GetD3D12Resource()->GetDesc();

	const size_t resourceHeapKindIndex =
	GetResourceHeapKind(resourceDescriptor.Dimension, heapProp.Type,
	resourceDescriptor.Flags, mResourceHeapTier);

	mSubAllocatedResourceAllocators[resourceHeapKindIndex]->Deallocate(allocation);
	}

	ResultOrError<ResourceHeapAllocation> ResourceAllocatorManager::CreatePlacedResource(
	D3D12_HEAP_TYPE heapType,
	const D3D12_RESOURCE_DESC& requestedResourceDescriptor,
	const D3D12_CLEAR_VALUE* optimizedClearValue,
	D3D12_RESOURCE_STATES initialUsage) {
	const ResourceHeapKind resourceHeapKind =
	GetResourceHeapKind(requestedResourceDescriptor.Dimension, heapType,
	requestedResourceDescriptor.Flags, mResourceHeapTier);

	D3D12_RESOURCE_DESC resourceDescriptor = requestedResourceDescriptor;
	resourceDescriptor.Alignment = GetResourcePlacementAlignment(
	resourceHeapKind, requestedResourceDescriptor.SampleDesc.Count,
	requestedResourceDescriptor.Alignment);

	// TODO(bryan.bernhart): Figure out how to compute the alignment without calling this
	// twice.
	D3D12_RESOURCE_ALLOCATION_INFO resourceInfo =
	mDevice->GetD3D12Device()->GetResourceAllocationInfo(0, 1, &resourceDescriptor);

	// If the requested resource alignment was rejected, let D3D tell us what the
	// required alignment is for this resource.
	if (resourceDescriptor.Alignment != 0 &&
	resourceDescriptor.Alignment != resourceInfo.Alignment) {
	resourceDescriptor.Alignment = 0;
	resourceInfo =
	mDevice->GetD3D12Device()->GetResourceAllocationInfo(0, 1, &resourceDescriptor);
	}

	// If d3d tells us the resource size is invalid, treat the error as OOM.
	// Otherwise, creating the resource could cause a device loss (too large).
	// This is because NextPowerOfTwo(UINT64_MAX) overflows and proceeds to
	// incorrectly allocate a mismatched size.
	if (resourceInfo.SizeInBytes == 0 \|\|
	resourceInfo.SizeInBytes == std::numeric_limits<uint64_t>::max()) {
	return DAWN_OUT_OF_MEMORY_ERROR("Resource allocation size was invalid.");
	}

	BuddyMemoryAllocator* allocator =
	mSubAllocatedResourceAllocators[static_cast<size_t>(resourceHeapKind)].get();

	ResourceMemoryAllocation allocation;
	DAWN_TRY_ASSIGN(allocation,
	allocator->Allocate(resourceInfo.SizeInBytes, resourceInfo.Alignment));
	if (allocation.GetInfo().mMethod == AllocationMethod::kInvalid) {
	return ResourceHeapAllocation{}; // invalid
	}

	Heap* heap = ToBackend(allocation.GetResourceHeap());

	// Before calling CreatePlacedResource, we must ensure the target heap is resident.
	// CreatePlacedResource will fail if it is not.
	DAWN_TRY(mDevice->GetResidencyManager()->LockAllocation(heap));

	// With placed resources, a single heap can be reused.
	// The resource placed at an offset is only reclaimed
	// upon Tick or after the last command list using the resource has completed
	// on the GPU. This means the same physical memory is not reused
	// within the same command-list and does not require additional synchronization (aliasing
	// barrier).
	// https://docs.microsoft.com/en-us/windows/win32/api/d3d12/nf-d3d12-id3d12device-createplacedresource
	ComPtr<ID3D12Resource> placedResource;
	DAWN_TRY(CheckOutOfMemoryHRESULT(
	mDevice->GetD3D12Device()->CreatePlacedResource(
	heap->GetD3D12Heap(), allocation.GetOffset(), &resourceDescriptor, initialUsage,
	optimizedClearValue, IID_PPV_ARGS(&placedResource)),
	"ID3D12Device::CreatePlacedResource"));

	// After CreatePlacedResource has finished, the heap can be unlocked from residency. This
	// will insert it into the residency LRU.
	mDevice->GetResidencyManager()->UnlockAllocation(heap);

	return ResourceHeapAllocation{allocation.GetInfo(), allocation.GetOffset(),
	std::move(placedResource), heap};
	}

	ResultOrError<ResourceHeapAllocation> ResourceAllocatorManager::CreateCommittedResource(
	D3D12_HEAP_TYPE heapType,
	const D3D12_RESOURCE_DESC& resourceDescriptor,
	const D3D12_CLEAR_VALUE* optimizedClearValue,
	D3D12_RESOURCE_STATES initialUsage) {
	D3D12_HEAP_PROPERTIES heapProperties;
	heapProperties.Type = heapType;
	heapProperties.CPUPageProperty = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
	heapProperties.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
	heapProperties.CreationNodeMask = 0;
	heapProperties.VisibleNodeMask = 0;

	// If d3d tells us the resource size is invalid, treat the error as OOM.
	// Otherwise, creating the resource could cause a device loss (too large).
	// This is because NextPowerOfTwo(UINT64_MAX) overflows and proceeds to
	// incorrectly allocate a mismatched size.
	D3D12_RESOURCE_ALLOCATION_INFO resourceInfo =
	mDevice->GetD3D12Device()->GetResourceAllocationInfo(0, 1, &resourceDescriptor);
	if (resourceInfo.SizeInBytes == 0 \|\|
	resourceInfo.SizeInBytes == std::numeric_limits<uint64_t>::max()) {
	return DAWN_OUT_OF_MEMORY_ERROR("Resource allocation size was invalid.");
	}

	if (resourceInfo.SizeInBytes > kMaxHeapSize) {
	return ResourceHeapAllocation{}; // Invalid
	}

	// CreateCommittedResource will implicitly make the created resource resident. We must
	// ensure enough free memory exists before allocating to avoid an out-of-memory error when
	// overcommitted.
	DAWN_TRY(mDevice->GetResidencyManager()->EnsureCanAllocate(
	resourceInfo.SizeInBytes, GetMemorySegment(mDevice, heapType)));

	// Note: Heap flags are inferred by the resource descriptor and do not need to be explicitly
	// provided to CreateCommittedResource.
	ComPtr<ID3D12Resource> committedResource;
	DAWN_TRY(CheckOutOfMemoryHRESULT(
	mDevice->GetD3D12Device()->CreateCommittedResource(
	&heapProperties, D3D12_HEAP_FLAG_NONE, &resourceDescriptor, initialUsage,
	optimizedClearValue, IID_PPV_ARGS(&committedResource)),
	"ID3D12Device::CreateCommittedResource"));

	// When using CreateCommittedResource, D3D12 creates an implicit heap that contains the
	// resource allocation. Because Dawn's memory residency management occurs at the resource
	// heap granularity, every directly allocated ResourceHeapAllocation also stores a Heap
	// object. This object is created manually, and must be deleted manually upon deallocation
	// of the committed resource.
	Heap* heap = new Heap(committedResource, GetMemorySegment(mDevice, heapType),
	resourceInfo.SizeInBytes);

	// Calling CreateCommittedResource implicitly calls MakeResident on the resource. We must
	// track this to avoid calling MakeResident a second time.
	mDevice->GetResidencyManager()->TrackResidentAllocation(heap);

	AllocationInfo info;
	info.mMethod = AllocationMethod::kDirect;

	return ResourceHeapAllocation{info,
	/offset/ 0, std::move(committedResource), heap};
	}

	void ResourceAllocatorManager::DestroyPool() {
	for (auto& alloc : mPooledHeapAllocators) {
	alloc->DestroyPool();
	}
	}

	}} // namespace dawn_native::d3d12