Page-locks the memory range specified by
bytesize and maps it for the device(s) as specified by
Flags. This memory range also is added to the same tracking mechanism as cuMemHostAlloc to automatically accelerate calls to functions such as cuMemcpyHtoD(). Since the memory can be accessed directly by the device, it can be read or written with much higher bandwidth than pageable memory that has not been registered. Page-locking excessive amounts of memory may degrade system performance, since it reduces the amount of memory available to the system for paging. As a result, this function is best used sparingly to register staging areas for data exchange between host and device.
This function has limited support on Mac OS X. OS 10.7 or higher is required.
Flags parameter enables different options to be specified that affect the allocation, as follows.
- CU_MEMHOSTREGISTER_PORTABLE: The memory returned by this call will be considered as pinned memory by all CUDA contexts, not just the one that performed the allocation.
All of these flags are orthogonal to one another: a developer may page-lock memory that is portable or mapped with no restrictions.
The CUDA context must have been created with the CU_CTX_MAP_HOST flag in order for the CU_MEMHOSTREGISTER_DEVICEMAP flag to have any effect.
The CU_MEMHOSTREGISTER_DEVICEMAP flag may be specified on CUDA contexts for devices that do not support mapped pinned memory. The failure is deferred to cuMemHostGetDevicePointer() because the memory may be mapped into other CUDA contexts via the CU_MEMHOSTREGISTER_PORTABLE flag.
The memory page-locked by this function must be unregistered with cuMemHostUnregister().
|p ||- Host pointer to memory to page-lock |
|bytesize ||- Size in bytes of the address range to page-lock |
|Flags ||- Flags for allocation request|
- CUDA_SUCCESS, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_INVALID_CONTEXT, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_OUT_OF_MEMORY
- Note that this function may also return error codes from previous, asynchronous launches.
- See also:
- cuMemHostUnregister, cuMemHostGetFlags, cuMemHostGetDevicePointer