/// <summary>
/// Constructs a page lock scope for the accelerator.
/// </summary>
/// <param name="accelerator">The associated accelerator.</param>
/// <param name="hostPtr">The host buffer pointer to page lock.</param>
/// <param name="numElements">The number of elements in the buffer.</param>
internal CudaPageLockScope(
CudaAccelerator accelerator,
IntPtr hostPtr,
long numElements)
: base(accelerator, numElements)
{
if (!accelerator.Device.SupportsMappingHostMemory)
{
throw new NotSupportedException(
RuntimeErrorMessages.NotSupportedPageLock);
}
HostPtr = hostPtr;
bool supportsHostPointer = accelerator
.Device
.SupportsUsingHostPointerForRegisteredMemory;
// Setup internal memory registration flags.
var flags = MemHostRegisterFlags.CU_MEMHOSTREGISTER_PORTABLE;
if (!supportsHostPointer)
{
flags |= MemHostRegisterFlags.CU_MEMHOSTREGISTER_DEVICEMAP;
}
// Perform the memory registration.
CudaException.ThrowIfFailed(
CurrentAPI.MemHostRegister(
hostPtr,
new IntPtr(LengthInBytes),
flags));
// Check whether we have to determine the actual device pointer or are able
// to reuse the host pointer for all operations.
if (supportsHostPointer)
{
AddrOfLockedObject = hostPtr;
}
else
{
CudaException.ThrowIfFailed(
CurrentAPI.MemHostGetDevicePointer(
out IntPtr devicePtr,
hostPtr,
0));
AddrOfLockedObject = devicePtr;
}
}
/// <summary>
/// Constructs a page lock scope for the accelerator.
/// </summary>
/// <param name="accelerator">The associated accelerator.</param>
/// <param name="hostPtr">The host buffer pointer to page lock.</param>
/// <param name="numElements">The number of elements in the buffer.</param>
internal CudaPageLockScope(
CudaAccelerator accelerator,
IntPtr hostPtr,
long numElements)
: base(accelerator)
{
if (!accelerator.Device.SupportsMappingHostMemory)
{
throw new NotSupportedException(
RuntimeErrorMessages.NotSupportedPageLock);
}
HostPtr = hostPtr;
Length = numElements;
var flags = MemHostRegisterFlags.CU_MEMHOSTREGISTER_PORTABLE;
if (!accelerator.Device.SupportsUsingHostPointerForRegisteredMemory)
{
flags |= MemHostRegisterFlags.CU_MEMHOSTREGISTER_DEVICEMAP;
}
CudaException.ThrowIfFailed(
CurrentAPI.MemHostRegister(
hostPtr,
new IntPtr(LengthInBytes),
flags));
if (accelerator.Device.SupportsUsingHostPointerForRegisteredMemory)
{
AddrOfLockedObject = hostPtr;
}
else
{
CudaException.ThrowIfFailed(
CurrentAPI.MemHostGetDevicePointer(
out IntPtr devicePtr,
hostPtr,
0));
AddrOfLockedObject = devicePtr;
}
}