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// Copyright 2018 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/DynamicUploader.h"
#include <utility>
#include "dawn/common/Math.h"
#include "dawn/native/Buffer.h"
#include "dawn/native/Device.h"
namespace dawn::native {
DynamicUploader::DynamicUploader(DeviceBase* device) : mDevice(device) {
mRingBuffers.emplace_back(
std::unique_ptr<RingBuffer>(new RingBuffer{nullptr, RingBufferAllocator(kRingBufferSize)}));
}
void DynamicUploader::ReleaseStagingBuffer(Ref<BufferBase> stagingBuffer) {
mReleasedStagingBuffers.Enqueue(std::move(stagingBuffer), mDevice->GetPendingCommandSerial());
}
ResultOrError<UploadHandle> DynamicUploader::AllocateInternal(uint64_t allocationSize,
ExecutionSerial serial) {
// Disable further sub-allocation should the request be too large.
if (allocationSize > kRingBufferSize) {
BufferDescriptor bufferDesc = {};
bufferDesc.usage = wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::MapWrite;
bufferDesc.size = Align(allocationSize, 4);
bufferDesc.mappedAtCreation = true;
bufferDesc.label = "Dawn_DynamicUploaderStaging";
IgnoreLazyClearCountScope scope(mDevice);
Ref<BufferBase> stagingBuffer;
DAWN_TRY_ASSIGN(stagingBuffer, mDevice->CreateBuffer(&bufferDesc));
UploadHandle uploadHandle;
uploadHandle.mappedBuffer = static_cast<uint8_t*>(stagingBuffer->GetMappedPointer());
uploadHandle.stagingBuffer = stagingBuffer.Get();
ReleaseStagingBuffer(std::move(stagingBuffer));
return uploadHandle;
}
// Note: Validation ensures size is already aligned.
// First-fit: find next smallest buffer large enough to satisfy the allocation request.
RingBuffer* targetRingBuffer = mRingBuffers.back().get();
for (auto& ringBuffer : mRingBuffers) {
const RingBufferAllocator& ringBufferAllocator = ringBuffer->mAllocator;
// Prevent overflow.
ASSERT(ringBufferAllocator.GetSize() >= ringBufferAllocator.GetUsedSize());
const uint64_t remainingSize =
ringBufferAllocator.GetSize() - ringBufferAllocator.GetUsedSize();
if (allocationSize <= remainingSize) {
targetRingBuffer = ringBuffer.get();
break;
}
}
uint64_t startOffset = RingBufferAllocator::kInvalidOffset;
if (targetRingBuffer != nullptr) {
startOffset = targetRingBuffer->mAllocator.Allocate(allocationSize, serial);
}
// Upon failure, append a newly created ring buffer to fulfill the
// request.
if (startOffset == RingBufferAllocator::kInvalidOffset) {
mRingBuffers.emplace_back(std::unique_ptr<RingBuffer>(
new RingBuffer{nullptr, RingBufferAllocator(kRingBufferSize)}));
targetRingBuffer = mRingBuffers.back().get();
startOffset = targetRingBuffer->mAllocator.Allocate(allocationSize, serial);
}
ASSERT(startOffset != RingBufferAllocator::kInvalidOffset);
// Allocate the staging buffer backing the ringbuffer.
// Note: the first ringbuffer will be lazily created.
if (targetRingBuffer->mStagingBuffer == nullptr) {
BufferDescriptor bufferDesc = {};
bufferDesc.usage = wgpu::BufferUsage::CopySrc | wgpu::BufferUsage::MapWrite;
bufferDesc.size = Align(targetRingBuffer->mAllocator.GetSize(), 4);
bufferDesc.mappedAtCreation = true;
bufferDesc.label = "Dawn_DynamicUploaderStaging";
IgnoreLazyClearCountScope scope(mDevice);
Ref<BufferBase> stagingBuffer;
DAWN_TRY_ASSIGN(stagingBuffer, mDevice->CreateBuffer(&bufferDesc));
targetRingBuffer->mStagingBuffer = std::move(stagingBuffer);
}
ASSERT(targetRingBuffer->mStagingBuffer != nullptr);
UploadHandle uploadHandle;
uploadHandle.stagingBuffer = targetRingBuffer->mStagingBuffer.Get();
uploadHandle.mappedBuffer =
static_cast<uint8_t*>(uploadHandle.stagingBuffer->GetMappedPointer()) + startOffset;
uploadHandle.startOffset = startOffset;
return uploadHandle;
}
void DynamicUploader::Deallocate(ExecutionSerial lastCompletedSerial) {
// Reclaim memory within the ring buffers by ticking (or removing requests no longer
// in-flight).
for (size_t i = 0; i < mRingBuffers.size(); ++i) {
mRingBuffers[i]->mAllocator.Deallocate(lastCompletedSerial);
// Never erase the last buffer as to prevent re-creating smaller buffers
// again. The last buffer is the largest.
if (mRingBuffers[i]->mAllocator.Empty() && i < mRingBuffers.size() - 1) {
mRingBuffers.erase(mRingBuffers.begin() + i);
}
}
mReleasedStagingBuffers.ClearUpTo(lastCompletedSerial);
}
// TODO(dawn:512): Optimize this function so that it doesn't allocate additional memory
// when it's not necessary.
ResultOrError<UploadHandle> DynamicUploader::Allocate(uint64_t allocationSize,
ExecutionSerial serial,
uint64_t offsetAlignment) {
ASSERT(offsetAlignment > 0);
UploadHandle uploadHandle;
DAWN_TRY_ASSIGN(uploadHandle, AllocateInternal(allocationSize + offsetAlignment - 1, serial));
uint64_t additionalOffset =
Align(uploadHandle.startOffset, offsetAlignment) - uploadHandle.startOffset;
uploadHandle.mappedBuffer = static_cast<uint8_t*>(uploadHandle.mappedBuffer) + additionalOffset;
uploadHandle.startOffset += additionalOffset;
return uploadHandle;
}
bool DynamicUploader::ShouldFlush() {
uint64_t kTotalAllocatedSizeThreshold = 64 * 1024 * 1024;
// We use total allocated size instead of pending-upload size to prevent Dawn from allocating
// too much GPU memory so that the risk of OOM can be minimized.
return GetTotalAllocatedSize() > kTotalAllocatedSizeThreshold;
}
uint64_t DynamicUploader::GetTotalAllocatedSize() {
uint64_t size = 0;
for (const auto& buffer : mReleasedStagingBuffers.IterateAll()) {
size += buffer->GetSize();
}
for (const auto& buffer : mRingBuffers) {
if (buffer->mStagingBuffer != nullptr) {
size += buffer->mStagingBuffer->GetSize();
}
}
return size;
}
} // namespace dawn::native