pinned_memory_resource.hpp

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/*
 * Copyright (c) 2020-2025, NVIDIA CORPORATION.
 *
 * 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
 *
 * https://apache.ac.cn/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.
 */
#pragma once

#include <rmm/aligned.hpp>
#include <rmm/cuda_stream_view.hpp>
#include <rmm/detail/aligned.hpp>
#include <rmm/detail/error.hpp>
#include <rmm/detail/export.hpp>
#include <rmm/mr/host/host_memory_resource.hpp>

#include <cstddef>

namespace RMM_NAMESPACE {
namespace mr {
class pinned_memory_resource final : public host_memory_resource {
 public
 pinned_memory_resource() = default;
 ~pinned_memory_resource() override = default;
 pinned_memory_resource(pinned_memory_resource const&) = default;
 pinned_memory_resource(pinned_memory_resource&&) = default;
 pinned_memory_resource& operator=(pinned_memory_resource const&) =
 default;
 pinned_memory_resource& operator=(pinned_memory_resource&&) =
 default;

 [[nodiscard]] void* allocate_async(std::size_t bytes, std::size_t alignment, cuda_stream_view)
 {
 return do_allocate(bytes, alignment);
 }

 [[nodiscard]] void* allocate_async(std::size_t bytes, cuda_stream_view)
 {
 return do_allocate(bytes);
 }

 void deallocate_async(void* ptr, std::size_t bytes, std::size_t alignment, cuda_stream_view)
 {
 do_deallocate(ptr, rmm::align_up(bytes, alignment));
 }

 friend void get_property(pinned_memory_resource const&, cuda::mr::device_accessible) noexcept {}

 private
 void* do_allocate(std::size_t bytes, std::size_t alignment = alignof(std::max_align_t)) override
 {
 // don't allocate anything if the user requested zero bytes
 if (0 == bytes) { return nullptr; }

 // If the requested alignment isn't supported, use default
 alignment =
 (rmm::is_supported_alignment(alignment)) ? alignment : rmm::RMM_DEFAULT_HOST_ALIGNMENT;

 return rmm::detail::aligned_host_allocate(bytes, alignment, [](std::size_t size) {
 void* ptr{nullptr};
 RMM_CUDA_TRY_ALLOC(cudaMallocHost(&ptr, size), size);
 return ptr;
 });
 }

 void do_deallocate(void* ptr,
 std::size_t bytes,
 std::size_t alignment = alignof(std::max_align_t)) override
 {
 if (nullptr == ptr) { return; }
 rmm::detail::aligned_host_deallocate(
 ptr, bytes, alignment, [](void* ptr) { RMM_ASSERT_CUDA_SUCCESS(cudaFreeHost(ptr)); });
 }
};
static_assert(cuda::mr::async_resource_with<pinned_memory_resource,
 cuda::mr::host_accessible,
 cuda::mr::device_accessible>); // end of group
} // namespace mr
} // namespace RMM_NAMESPACE