Kokkos_HostSpace.hpp

//@HEADER
// ************************************************************************
//
//                        Kokkos v. 4.0
//       Copyright (2022) National Technology & Engineering
//               Solutions of Sandia, LLC (NTESS).
//
// Under the terms of Contract DE-NA0003525 with NTESS,
// the U.S. Government retains certain rights in this software.
//
// Part of Kokkos, under the Apache License v2.0 with LLVM Exceptions.
// See https://kokkos.org/LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//@HEADER

#ifndef KOKKOS_IMPL_PUBLIC_INCLUDE
#include <Kokkos_Macros.hpp>
static_assert(false,
              "Including non-public Kokkos header files is not allowed.");
#endif
#ifndef KOKKOS_HOSTSPACE_HPP
#define KOKKOS_HOSTSPACE_HPP

#include <cstring>
#include <string>
#include <iosfwd>
#include <typeinfo>

#include <Kokkos_Core_fwd.hpp>
#include <Kokkos_Concepts.hpp>
#include <Kokkos_MemoryTraits.hpp>

#include <impl/Kokkos_Traits.hpp>
#include <impl/Kokkos_Error.hpp>
#include <impl/Kokkos_SharedAlloc.hpp>
#include <impl/Kokkos_Tools.hpp>

#include "impl/Kokkos_HostSpace_deepcopy.hpp"
#include <impl/Kokkos_MemorySpace.hpp>

/*--------------------------------------------------------------------------*/

namespace Kokkos {

namespace Impl {

void init_lock_array_host_space();

bool lock_address_host_space(void* ptr);

void unlock_address_host_space(void* ptr);

}  // namespace Impl

}  // namespace Kokkos

namespace Kokkos {
class HostSpace {
 public:
  using memory_space = HostSpace;
  using size_type    = size_t;

  using execution_space = DefaultHostExecutionSpace;

  using device_type = Kokkos::Device<execution_space, memory_space>;

  HostSpace();
  HostSpace(HostSpace&& rhs)      = default;
  HostSpace(const HostSpace& rhs) = default;
  HostSpace& operator=(HostSpace&&) = default;
  HostSpace& operator=(const HostSpace&) = default;
  ~HostSpace()                           = default;

  enum AllocationMechanism {
    STD_MALLOC,
    POSIX_MEMALIGN,
    POSIX_MMAP,
    INTEL_MM_ALLOC
  };

  explicit HostSpace(const AllocationMechanism&);

  void* allocate(const size_t arg_alloc_size) const;
  void* allocate(const char* arg_label, const size_t arg_alloc_size,
                 const size_t arg_logical_size = 0) const;

  void deallocate(void* const arg_alloc_ptr, const size_t arg_alloc_size) const;
  void deallocate(const char* arg_label, void* const arg_alloc_ptr,
                  const size_t arg_alloc_size,
                  const size_t arg_logical_size = 0) const;

 private:
  template <class, class, class, class>
  friend class Kokkos::Experimental::LogicalMemorySpace;

  void* impl_allocate(const char* arg_label, const size_t arg_alloc_size,
                      const size_t arg_logical_size = 0,
                      const Kokkos::Tools::SpaceHandle =
                          Kokkos::Tools::make_space_handle(name())) const;
  void impl_deallocate(const char* arg_label, void* const arg_alloc_ptr,
                       const size_t arg_alloc_size,
                       const size_t arg_logical_size = 0,
                       const Kokkos::Tools::SpaceHandle =
                           Kokkos::Tools::make_space_handle(name())) const;

 public:
  static constexpr const char* name() { return m_name; }

 private:
  AllocationMechanism m_alloc_mech;
  static constexpr const char* m_name = "Host";
  friend class Kokkos::Impl::SharedAllocationRecord<Kokkos::HostSpace, void>;
};

}  // namespace Kokkos

//----------------------------------------------------------------------------

namespace Kokkos {

namespace Impl {

static_assert(Kokkos::Impl::MemorySpaceAccess<Kokkos::HostSpace,
                                              Kokkos::HostSpace>::assignable,
              "");

template <typename S>
struct HostMirror {
 private:
  // If input execution space can access HostSpace then keep it.
  // Example: Kokkos::OpenMP can access, Kokkos::Cuda cannot
  enum {
    keep_exe = Kokkos::Impl::MemorySpaceAccess<
        typename S::execution_space::memory_space,
        Kokkos::HostSpace>::accessible
  };

  // If HostSpace can access memory space then keep it.
  // Example:  Cannot access Kokkos::CudaSpace, can access Kokkos::CudaUVMSpace
  enum {
    keep_mem =
        Kokkos::Impl::MemorySpaceAccess<Kokkos::HostSpace,
                                        typename S::memory_space>::accessible
  };

 public:
  using Space = std::conditional_t<
      keep_exe && keep_mem, S,
      std::conditional_t<keep_mem,
                         Kokkos::Device<Kokkos::HostSpace::execution_space,
                                        typename S::memory_space>,
                         Kokkos::HostSpace>>;
};

}  // namespace Impl

}  // namespace Kokkos

//----------------------------------------------------------------------------

namespace Kokkos {

namespace Impl {

template <>
class SharedAllocationRecord<Kokkos::HostSpace, void>
    : public SharedAllocationRecordCommon<Kokkos::HostSpace> {
 private:
  friend Kokkos::HostSpace;
  friend class SharedAllocationRecordCommon<Kokkos::HostSpace>;

  using base_t     = SharedAllocationRecordCommon<Kokkos::HostSpace>;
  using RecordBase = SharedAllocationRecord<void, void>;

  SharedAllocationRecord(const SharedAllocationRecord&) = delete;
  SharedAllocationRecord& operator=(const SharedAllocationRecord&) = delete;

#ifdef KOKKOS_ENABLE_DEBUG

  static RecordBase s_root_record;
#endif

  const Kokkos::HostSpace m_space;

 protected:
  ~SharedAllocationRecord();
  SharedAllocationRecord() = default;

  // This constructor does not forward to the one without exec_space arg
  // in order to work around https://github.com/kokkos/kokkos/issues/5258
  // This constructor is templated so I can't just put it into the cpp file
  // like the other constructor.
  template <typename ExecutionSpace>
  SharedAllocationRecord(
      const ExecutionSpace& /* exec_space*/, const Kokkos::HostSpace& arg_space,
      const std::string& arg_label, const size_t arg_alloc_size,
      const RecordBase::function_type arg_dealloc = &deallocate)
      : base_t(
#ifdef KOKKOS_ENABLE_DEBUG
            &SharedAllocationRecord<Kokkos::HostSpace, void>::s_root_record,
#endif
            Impl::checked_allocation_with_header(arg_space, arg_label,
                                                 arg_alloc_size),
            sizeof(SharedAllocationHeader) + arg_alloc_size, arg_dealloc,
            arg_label),
        m_space(arg_space) {
    this->base_t::_fill_host_accessible_header_info(*RecordBase::m_alloc_ptr,
                                                    arg_label);
  }

  SharedAllocationRecord(
      const Kokkos::HostSpace& arg_space, const std::string& arg_label,
      const size_t arg_alloc_size,
      const RecordBase::function_type arg_dealloc = &deallocate);

 public:
  KOKKOS_INLINE_FUNCTION static SharedAllocationRecord* allocate(
      const Kokkos::HostSpace& arg_space, const std::string& arg_label,
      const size_t arg_alloc_size) {
    KOKKOS_IF_ON_HOST((return new SharedAllocationRecord(arg_space, arg_label,
                                                         arg_alloc_size);))
    KOKKOS_IF_ON_DEVICE(((void)arg_space; (void)arg_label; (void)arg_alloc_size;
                         return nullptr;))
  }
};

}  // namespace Impl

}  // namespace Kokkos

//----------------------------------------------------------------------------

namespace Kokkos {

namespace Impl {

template <class DT, class... DP>
struct ZeroMemset<typename HostSpace::execution_space, DT, DP...> {
  ZeroMemset(const typename HostSpace::execution_space& exec,
             const View<DT, DP...>& dst,
             typename View<DT, DP...>::const_value_type&) {
    // Host spaces, except for HPX, are synchronous and we need to fence for HPX
    // since we can't properly enqueue a std::memset otherwise.
    // We can't use exec.fence() directly since we don't have a full definition
    // of HostSpace here.
    hostspace_fence(exec);
    using ValueType = typename View<DT, DP...>::value_type;
    std::memset(dst.data(), 0, sizeof(ValueType) * dst.size());
  }

  ZeroMemset(const View<DT, DP...>& dst,
             typename View<DT, DP...>::const_value_type&) {
    using ValueType = typename View<DT, DP...>::value_type;
    std::memset(dst.data(), 0, sizeof(ValueType) * dst.size());
  }
};

template <>
struct DeepCopy<HostSpace, HostSpace, DefaultHostExecutionSpace> {
  DeepCopy(void* dst, const void* src, size_t n) {
    hostspace_parallel_deepcopy(dst, src, n);
  }

  DeepCopy(const DefaultHostExecutionSpace& exec, void* dst, const void* src,
           size_t n) {
    hostspace_parallel_deepcopy_async(exec, dst, src, n);
  }
};

template <class ExecutionSpace>
struct DeepCopy<HostSpace, HostSpace, ExecutionSpace> {
  DeepCopy(void* dst, const void* src, size_t n) {
    hostspace_parallel_deepcopy(dst, src, n);
  }

  DeepCopy(const ExecutionSpace& exec, void* dst, const void* src, size_t n) {
    exec.fence(
        "Kokkos::Impl::DeepCopy<HostSpace, HostSpace, "
        "ExecutionSpace>::DeepCopy: fence before copy");
    hostspace_parallel_deepcopy_async(dst, src, n);
  }
};

}  // namespace Impl

}  // namespace Kokkos

#endif  // #define KOKKOS_HOSTSPACE_HPP