Functions

CUresult cuMemAddressFree ( CUdeviceptr ptr, size_t size )

Free an address range reservation.

Parameters

ptr

- Starting address of the virtual address range to free

size

- Size of the virtual address region to free

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

Frees a virtual address range reserved by cuMemAddressReserve. The size must match what was given to memAddressReserve and the ptr given must match what was returned from memAddressReserve.

See also:

cuMemAddressReserve

CUresult cuMemAddressReserve ( CUdeviceptr* ptr, size_t size, size_t alignment, CUdeviceptr addr, unsigned long long flags )

Allocate an address range reservation.

Parameters

ptr

- Resulting pointer to start of virtual address range allocated

size

- Size of the reserved virtual address range requested

alignment

- Alignment of the reserved virtual address range requested

addr

- Fixed starting address range requested

flags

- Currently unused, must be zero

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_OUT_OF_MEMORY, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

Reserves a virtual address range based on the given parameters, giving the starting address of the range in ptr. This API requires a system that supports UVA. The size and address parameters must be a multiple of the host page size and the alignment must be a power of two or zero for default alignment.

See also:

cuMemAddressFree

CUresult cuMemCreate ( CUmemGenericAllocationHandle* handle, size_t size, const CUmemAllocationProp* prop, unsigned long long flags )

Create a shareable memory handle representing a memory allocation of a given size described by the given properties.

Parameters

handle

- Value of handle returned. All operations on this allocation are to be performed using this handle.

size

- Size of the allocation requested

prop

- Properties of the allocation to create.

flags

- flags for future use, must be zero now.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_OUT_OF_MEMORY, CUDA_ERROR_INVALID_DEVICE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

This creates a memory allocation on the target device specified through the prop strcuture. The created allocation will not have any device or host mappings. The generic memory handle for the allocation can be mapped to the address space of calling process via cuMemMap. This handle cannot be transmitted directly to other processes (see cuMemExportToShareableHandle). On Windows, the caller must also pass an LPSECURITYATTRIBUTE in prop to be associated with this handle which limits or allows access to this handle for a recepient process (see CUmemAllocationProp::win32HandleMetaData for more). The size of this allocation must be a multiple of the the value given via cuMemGetAllocationGranularity with the CU_MEM_ALLOC_GRANULARITY_MINIMUM flag.

Note:

Note that this function may also return error codes from previous, asynchronous launches.

See also:

cuMemRelease, cuMemExportToShareableHandle, cuMemImportFromShareableHandle

CUresult cuMemExportToShareableHandle ( void* shareableHandle, CUmemGenericAllocationHandle handle, CUmemAllocationHandleType handleType, unsigned long long flags )

Exports an allocation to a requested shareable handle type.

Parameters

shareableHandle

- Pointer to the location in which to store the requested handle type

handle

- CUDA handle for the memory allocation

handleType

- Type of shareable handle requested (defines type and size of the shareableHandle output parameter)

flags

- Reserved, must be zero

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

Given a CUDA memory handle, create a shareable memory allocation handle that can be used to share the memory with other processes. The recipient process can convert the shareable handle back into a CUDA memory handle using cuMemImportFromShareableHandle and map it with cuMemMap. The implementation of what this handle is and how it can be transferred is defined by the requested handle type in handleType

Once all shareable handles are closed and the allocation is released, the allocated memory referenced will be released back to the OS and uses of the CUDA handle afterward will lead to undefined behavior.

This API can also be used in conjunction with other APIs (e.g. Vulkan, OpenGL) that support importing memory from the shareable type

See also:

cuMemImportFromShareableHandle

CUresult cuMemGetAccess ( unsigned long long* flags, const CUmemLocation* location, CUdeviceptr ptr )

Get the access flags set for the given location and ptr.

Parameters

flags

- Flags set for this location

location

- Location in which to check the flags for

ptr

- Address in which to check the access flags for

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_INVALID_DEVICE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

See also:

cuMemSetAccess

CUresult cuMemGetAllocationGranularity ( size_t* granularity, const CUmemAllocationProp* prop, CUmemAllocationGranularity_flags option )

Calculates either the minimal or recommended granularity.

Parameters

granularity

Returned granularity.

prop

Property for which to determine the granularity for

option

Determines which granularity to return

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

Calculates either the minimal or recommended granularity for a given allocation specification and returns it in granularity. This granularity can be used as a multiple for alignment, size, or address mapping.

See also:

cuMemCreate, cuMemMap

CUresult cuMemGetAllocationPropertiesFromHandle ( CUmemAllocationProp* prop, CUmemGenericAllocationHandle handle )

Retrieve the contents of the property structure defining properties for this handle.

Parameters

prop

- Pointer to a properties structure which will hold the information about this handle

handle

- Handle which to perform the query on

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

See also:

cuMemCreate, cuMemImportFromShareableHandle

CUresult cuMemImportFromShareableHandle ( CUmemGenericAllocationHandle* handle, void* osHandle, CUmemAllocationHandleType shHandleType )

Imports an allocation from a requested shareable handle type.

Parameters

handle

- CUDA Memory handle for the memory allocation.

osHandle

- Shareable Handle representing the memory allocation that is to be imported.

shHandleType

- handle type of the exported handle CUmemAllocationHandleType.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

If the current process cannot support the memory described by this shareable handle, this API will error as CUDA_ERROR_NOT_SUPPORTED.

Note:

Importing shareable handles exported from some graphics APIs(Vulkan, OpenGL, etc) created on devices under an SLI group may not be supported, and thus this API will return CUDA_ERROR_NOT_SUPPORTED. There is no guarantee that the contents of handle will be the same CUDA memory handle for the same given OS shareable handle, or the same underlying allocation.

See also:

cuMemExportToShareableHandle, cuMemMap, cuMemRelease

CUresult cuMemMap ( CUdeviceptr ptr, size_t size, size_t offset, CUmemGenericAllocationHandle handle, unsigned long long flags )

Maps an allocation handle to a reserved virtual address range.

Parameters

ptr

- Address where memory will be mapped.

size

- Size of the memory mapping.

offset

- Offset into the memory represented by

• handle from which to start mapping
• Note: currently must be zero.

handle

- Handle to a shareable memory

flags

- flags for future use, must be zero now.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_INVALID_DEVICE, CUDA_ERROR_OUT_OF_MEMORY, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

Maps bytes of memory represented by handle starting from byte offset to size to address range [addr, addr + size]. This range must be an address reservation previously reserved with cuMemAddressReserve, and offset + size must be less than the size of the memory allocation. Both ptr, size, and offset must be a multiple of the value given via cuMemGetAllocationGranularity with the CU_MEM_ALLOC_GRANULARITY_MINIMUM flag.

Please note calling cuMemMap does not make the address accessible, the caller needs to update accessibility of a contiguous mapped VA range by calling cuMemSetAccess.

Once a recipient process obtains a shareable memory handle from cuMemImportFromShareableHandle, the process must use cuMemMap to map the memory into its address ranges before setting accessibility with cuMemSetAccess.

cuMemMap can only create mappings on VA range reservations that are not currently mapped.

Note:

Note that this function may also return error codes from previous, asynchronous launches.

See also:

cuMemUnmap, cuMemSetAccess, cuMemCreate, cuMemAddressReserve, cuMemImportFromShareableHandle

CUresult cuMemRelease ( CUmemGenericAllocationHandle handle )

Release a memory handle representing a memory allocation which was previously allocated through cuMemCreate.

Parameters

handle

Value of handle which was returned previously by cuMemCreate.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

Frees the memory that was allocated on a device through cuMemCreate.

The memory allocation will be freed when all outstanding mappings to the memory are unmapped and when all outstanding references to the handle (including it's shareable counterparts) are also released. The generic memory handle can be freed when there are still outstanding mappings made with this handle. Each time a recepient process imports a shareable handle, it needs to pair it with cuMemRelease for the handle to be freed. If handle is not a valid handle the behavior is undefined.

Note:

Note that this function may also return error codes from previous, asynchronous launches.

See also:

cuMemCreate

CUresult cuMemRetainAllocationHandle ( CUmemGenericAllocationHandle* handle, void* addr )

Given an address addr, returns the allocation handle of the backing memory allocation.

Parameters

handle

CUDA Memory handle for the backing memory allocation.

addr

Memory address to query, that has been mapped previously.

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

The handle is guaranteed to be the same handle value used to map the memory. If the address requested is not mapped, the function will fail. The returned handle must be released with corresponding number of calls to cuMemRelease.

Note:

The address addr, can be any address in a range previously mapped by cuMemMap, and not necessarily the start address.

See also:

cuMemCreate, cuMemRelease, cuMemMap

CUresult cuMemSetAccess ( CUdeviceptr ptr, size_t size, const CUmemAccessDesc* desc, size_t count )

Set the access flags for each location specified in desc for the given virtual address range.

Parameters

ptr

- Starting address for the virtual address range

size

- Length of the virtual address range

desc

- Array of CUmemAccessDesc that describe how to change the

• mapping for each location specified

count

- Number of CUmemAccessDesc in desc

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_INVALID_DEVICE, CUDA_ERROR_NOT_SUPPORTED

Description

Given the virtual address range via ptr and size, and the locations in the array given by desc and count, set the access flags for the target locations. The range must be a fully mapped address range containing all allocations created by cuMemMap / cuMemCreate.

Note:

• Note that this function may also return error codes from previous, asynchronous launches.

• This function exhibits synchronous behavior for most use cases.

See also:

cuMemSetAccess, cuMemCreate, :cuMemMap

CUresult cuMemUnmap ( CUdeviceptr ptr, size_t size )

Unmap the backing memory of a given address range.

Parameters

ptr

- Starting address for the virtual address range to unmap

size

- Size of the virtual address range to unmap

Returns

CUDA_SUCCESS, CUDA_ERROR_INVALID_VALUE, CUDA_ERROR_NOT_INITIALIZED, CUDA_ERROR_DEINITIALIZED, CUDA_ERROR_NOT_PERMITTED, CUDA_ERROR_NOT_SUPPORTED

Description

The range must be the entire contiguous address range that was mapped to. In other words, cuMemUnmap cannot unmap a sub-range of an address range mapped by cuMemCreate / cuMemMap. Any backing memory allocations will be freed if there are no existing mappings and there are no unreleased memory handles.

When cuMemUnmap returns successfully the address range is converted to an address reservation and can be used for a future calls to cuMemMap. Any new mapping to this virtual address will need to have access granted through cuMemSetAccess, as all mappings start with no accessibility setup.

Note:

• Note that this function may also return error codes from previous, asynchronous launches.

• This function exhibits synchronous behavior for most use cases.

See also:

cuMemCreate, cuMemAddressReserve