UCT Memory Domain

Data Structures
struct	uct_md_attr
	Memory domain attributes. More...
struct	uct_md_attr.cap
struct	uct_md_mem_attr
	Memory domain attributes. More...
struct	uct_allocated_memory
	Describes a memory allocated by UCT. More...
struct	uct_rkey_bundle
	Remote key with its type. More...
struct	uct_mem_alloc_params_t
	Parameters for allocating memory using uct_mem_alloc. More...
struct	uct_mem_alloc_params_t.mds

Typedefs
typedef enum uct_md_mem_attr_field	uct_md_mem_attr_field_t
	UCT MD memory attributes field mask. More...
typedef struct uct_md_mem_attr	uct_md_mem_attr_t
	Memory domain attributes. More...
typedef struct uct_allocated_memory	uct_allocated_memory_t
	Describes a memory allocated by UCT. More...
typedef struct uct_rkey_bundle	uct_rkey_bundle_t
	Remote key with its type. More...

Enumerations
enum	uct_sockaddr_accessibility_t { UCT_SOCKADDR_ACC_LOCAL, UCT_SOCKADDR_ACC_REMOTE }
	Socket address accessibility type. More...
enum	{   UCT_MD_FLAG_ALLOC = UCS_BIT(0), UCT_MD_FLAG_REG = UCS_BIT(1), UCT_MD_FLAG_NEED_MEMH = UCS_BIT(2), UCT_MD_FLAG_NEED_RKEY = UCS_BIT(3),   UCT_MD_FLAG_ADVISE = UCS_BIT(4), UCT_MD_FLAG_FIXED = UCS_BIT(5), UCT_MD_FLAG_RKEY_PTR = UCS_BIT(6), UCT_MD_FLAG_SOCKADDR = UCS_BIT(7),   UCT_MD_FLAG_INVALIDATE = UCS_BIT(8), UCT_MD_FLAG_EXPORTED_MKEY = UCS_BIT(9), UCT_MD_FLAG_REG_DMABUF = UCS_BIT(10) }
	Memory domain capability flags. More...
enum	uct_md_mem_flags {   UCT_MD_MEM_FLAG_NONBLOCK = UCS_BIT(0), UCT_MD_MEM_FLAG_FIXED = UCS_BIT(1), UCT_MD_MEM_FLAG_LOCK = UCS_BIT(2), UCT_MD_MEM_FLAG_HIDE_ERRORS = UCS_BIT(3),   UCT_MD_MEM_ACCESS_REMOTE_PUT = UCS_BIT(5), UCT_MD_MEM_ACCESS_REMOTE_GET = UCS_BIT(6), UCT_MD_MEM_ACCESS_REMOTE_ATOMIC = UCS_BIT(7), UCT_MD_MEM_ACCESS_LOCAL_READ = UCS_BIT(8),   UCT_MD_MEM_ACCESS_LOCAL_WRITE = UCS_BIT(9), UCT_MD_MEM_ACCESS_ALL, UCT_MD_MEM_ACCESS_RMA }
	Memory allocation/registration flags. More...
enum	uct_mem_advice_t { UCT_MADV_NORMAL = 0, UCT_MADV_WILLNEED }
	list of UCT memory use advice More...
enum	uct_md_mem_attr_field {   UCT_MD_MEM_ATTR_FIELD_MEM_TYPE = UCS_BIT(0), UCT_MD_MEM_ATTR_FIELD_SYS_DEV = UCS_BIT(1), UCT_MD_MEM_ATTR_FIELD_BASE_ADDRESS = UCS_BIT(2), UCT_MD_MEM_ATTR_FIELD_ALLOC_LENGTH = UCS_BIT(3),   UCT_MD_MEM_ATTR_FIELD_DMABUF_FD = UCS_BIT(4), UCT_MD_MEM_ATTR_FIELD_DMABUF_OFFSET = UCS_BIT(5) }
	UCT MD memory attributes field mask. More...
enum	uct_mem_alloc_params_field_t {   UCT_MEM_ALLOC_PARAM_FIELD_FLAGS = UCS_BIT(0), UCT_MEM_ALLOC_PARAM_FIELD_ADDRESS = UCS_BIT(1), UCT_MEM_ALLOC_PARAM_FIELD_MEM_TYPE = UCS_BIT(2), UCT_MEM_ALLOC_PARAM_FIELD_MDS = UCS_BIT(3),   UCT_MEM_ALLOC_PARAM_FIELD_NAME = UCS_BIT(4) }
	UCT allocation parameters specification field mask. More...

Functions
ucs_status_t	uct_md_mem_query (uct_md_h md, const void *address, size_t length, uct_md_mem_attr_t *mem_attr)
	Query attributes of a given pointer. More...
ucs_status_t	uct_md_query (uct_md_h md, uct_md_attr_t *md_attr)
	Query for memory domain attributes. More...
ucs_status_t	uct_md_mem_advise (uct_md_h md, uct_mem_h memh, void *addr, size_t length, uct_mem_advice_t advice)
	Give advice about the use of memory. More...
ucs_status_t	uct_md_mem_reg (uct_md_h md, void *address, size_t length, unsigned flags, uct_mem_h *memh_p)
	Register memory for zero-copy sends and remote access. More...
ucs_status_t	uct_md_mem_dereg (uct_md_h md, uct_mem_h memh)
	Undo the operation of uct_md_mem_reg(). More...
ucs_status_t	uct_md_detect_memory_type (uct_md_h md, const void *addr, size_t length, ucs_memory_type_t *mem_type_p)
	Detect memory type. More...
ucs_status_t	uct_mem_alloc (size_t length, const uct_alloc_method_t *methods, unsigned num_methods, const uct_mem_alloc_params_t *params, uct_allocated_memory_t *mem)
	Allocate memory for zero-copy communications and remote access. More...
ucs_status_t	uct_mem_free (const uct_allocated_memory_t *mem)
	Release allocated memory. More...
ucs_status_t	uct_md_config_read (uct_component_h component, const char *env_prefix, const char *filename, uct_md_config_t **config_p)
	Read the configuration for a memory domain. More...
int	uct_md_is_sockaddr_accessible (uct_md_h md, const ucs_sock_addr_t *sockaddr, uct_sockaddr_accessibility_t mode)
	Check if remote sock address is accessible from the memory domain. More...
ucs_status_t	uct_md_mkey_pack (uct_md_h md, uct_mem_h memh, void *rkey_buffer)
	Pack a remote key. More...
ucs_status_t	uct_rkey_unpack (uct_component_h component, const void *rkey_buffer, uct_rkey_bundle_t *rkey_ob)
	Unpack a remote key. More...
ucs_status_t	uct_rkey_ptr (uct_component_h component, uct_rkey_bundle_t *rkey_ob, uint64_t remote_addr, void **addr_p)
	Get a local pointer to remote memory. More...
ucs_status_t	uct_rkey_release (uct_component_h component, const uct_rkey_bundle_t *rkey_ob)
	Release a remote key. More...

Detailed Description

The Memory Domain abstracts resources required for network communication, which typically includes memory, transport mechanisms, compute and network resources. It is an isolation mechanism that can be employed by the applications for isolating resources between multiple programming models. The attributes of the Memory Domain are defined by the structure uct_md_attr(). The communication and memory operations are defined in the context of Memory Domain.

---

Data Structure Documentation

struct uct_md_attr

This structure defines the attributes of a Memory Domain which includes maximum memory that can be allocated, credentials required for accessing the memory, CPU mask indicating the proximity of CPUs, and bitmaps indicating the types of memory (CPU/CUDA/ROCM) that can be detected, allocated and accessed.

Examples:

uct_hello_world.c.

Data Fields
struct uct_md_attr	cap
ucs_linear_func_t	reg_cost	Memory registration cost estimation (time,seconds) as a linear function of the buffer size.
char	component_name[UCT_COMPONENT_NAME_MAX]	Component name
size_t	rkey_packed_size	Size of buffer needed for packed rkey
ucs_cpu_set_t	local_cpus	Mask of CPUs near the resource

struct uct_md_attr.cap

Data Fields
uint64_t	max_alloc	Maximal allocation size
size_t	max_reg	Maximal registration size
uint64_t	flags	UCT_MD_FLAG_xx
uint64_t	reg_mem_types	Bitmap of memory types that Memory Domain can be registered with
uint64_t	detect_mem_types	Bitmap of memory types that Memory Domain can detect if address belongs to it
uint64_t	alloc_mem_types	Bitmap of memory types that Memory Domain can allocate memory on
uint64_t	access_mem_types	Memory types that Memory Domain can access

struct uct_md_mem_attr

This structure defines the attributes of a memory pointer which may include the memory type of the pointer, and the system device that backs the pointer depending on the bit fields populated in field_mask.

Data Fields
uint64_t	field_mask	Mask of valid fields in this structure, using bits from uct_md_mem_attr_field_t.
ucs_memory_type_t	mem_type	The type of memory. E.g. CPU/GPU memory or some other valid type. If the md does not support sys_dev query, then UCS_MEMORY_TYPE_UNKNOWN is returned.
ucs_sys_device_t	sys_dev	Index of the system device on which the buffer resides. eg: NUMA/GPU If the md does not support sys_dev query, then UCS_SYS_DEVICE_ID_UNKNOWN is returned.
void *	base_address	Base address of the allocation to which the provided buffer belongs to. If the md not support base address query, then the pointer passed to uct_md_mem_query is returned as is.
size_t	alloc_length	Length of the whole allocation to which the provided buffer belongs to. If the md not support querying allocation length, then the length passed to uct_md_mem_query is returned as is.
int	dmabuf_fd	Dmabuf file descriptor to expose memory regions across devices. Refer (https://01.org/linuxgraphics/gfx-docs/drm/driver-api/dma-buf.html). If the md does not support querying the fd object associated with the region, then dmabuf_fd is set to UCT_DMABUF_FD_INVALID by uct_md_mem_query(). It is the responsibility of the user to close the returned fd using close (2) when it's no longer needed.
size_t	dmabuf_offset	Offset of the given address from the start of the memory region (identified by dmabuf_fd) backing the memory region being queried.

struct uct_allocated_memory

This structure describes the memory block which includes the address, size, and Memory Domain used for allocation. This structure is passed to interface and the memory is allocated by memory allocation functions uct_mem_alloc.

Data Fields
void *	address	Address of allocated memory
size_t	length	Real size of allocated memory
uct_alloc_method_t	method	Method used to allocate the memory
ucs_memory_type_t	mem_type	type of allocated memory
uct_md_h	md	if method==MD: MD used to allocate the memory
uct_mem_h	memh	if method==MD: MD memory handle

struct uct_rkey_bundle

This structure describes the credentials (typically key) and information required to access the remote memory by the communication interfaces.

Data Fields
uct_rkey_t	rkey	Remote key descriptor, passed to RMA functions
void *	handle	Handle, used internally for releasing the key
void *	type	Remote key type

struct uct_mem_alloc_params_t

Data Fields
uint64_t	field_mask	Mask of valid fields in this structure, using bits from uct_mem_alloc_params_field_t. Fields not specified in this mask will be ignored.
unsigned	flags	Memory allocation flags, see uct_md_mem_flags If UCT_MEM_ALLOC_PARAM_FIELD_FLAGS is not specified in field_mask, then (UCT_MD_MEM_ACCESS_LOCAL_READ | UCT_MD_MEM_ACCESS_LOCAL_WRITE) is used by default.
void *	address	If address is NULL, the underlying allocation routine will choose the address at which to create the mapping. If address is non-NULL and UCT_MD_MEM_FLAG_FIXED is not set, the address will be interpreted as a hint as to where to establish the mapping. If address is non-NULL and UCT_MD_MEM_FLAG_FIXED is set, then the specified address is interpreted as a requirement. In this case, if the mapping to the exact address cannot be made, the allocation request fails.
ucs_memory_type_t	mem_type	Type of memory to be allocated.
struct uct_mem_alloc_params_t	mds
const char *	name	Name of the allocated region, used to track memory usage for debugging and profiling. If UCT_MEM_ALLOC_PARAM_FIELD_NAME is not specified in field_mask, then "anonymous-uct_mem_alloc" is used by default.

struct uct_mem_alloc_params_t.mds

Data Fields
const uct_md_h *	mds	Array of memory domains to attempt to allocate the memory with, for MD allocation method.
unsigned	count	Length of 'mds' array. May be empty, in such case 'mds' may be NULL, and MD allocation method will be skipped.

Typedef Documentation

typedef enum uct_md_mem_attr_field uct_md_mem_attr_field_t

The enumeration allows specifying which fields in uct_md_mem_attr_t are present.

typedef struct uct_md_mem_attr uct_md_mem_attr_t

This structure defines the attributes of a memory pointer which may include the memory type of the pointer, and the system device that backs the pointer depending on the bit fields populated in field_mask.

typedef struct uct_allocated_memory uct_allocated_memory_t

This structure describes the memory block which includes the address, size, and Memory Domain used for allocation. This structure is passed to interface and the memory is allocated by memory allocation functions uct_mem_alloc.

typedef struct uct_rkey_bundle uct_rkey_bundle_t

This structure describes the credentials (typically key) and information required to access the remote memory by the communication interfaces.

Enumeration Type Documentation

enum uct_sockaddr_accessibility_t

Enumerator
UCT_SOCKADDR_ACC_LOCAL	Check if local address exists. Address should belong to a local network interface
UCT_SOCKADDR_ACC_REMOTE	Check if remote address can be reached. Address is routable from one of the local network interfaces

anonymous enum

Enumerator
UCT_MD_FLAG_ALLOC	MD supports memory allocation
UCT_MD_FLAG_REG	MD supports memory registration
UCT_MD_FLAG_NEED_MEMH	The transport needs a valid local memory handle for zero-copy operations
UCT_MD_FLAG_NEED_RKEY	The transport needs a valid remote memory key for remote memory operations
UCT_MD_FLAG_ADVISE	MD supports memory advice
UCT_MD_FLAG_FIXED	MD supports memory allocation with fixed address
UCT_MD_FLAG_RKEY_PTR	MD supports direct access to remote memory via a pointer that is returned by uct_rkey_ptr. Note This flag is deprecated and replaced by UCT_COMPONENT_FLAG_RKEY_PTR.
UCT_MD_FLAG_SOCKADDR	MD support for client-server connection establishment via sockaddr
UCT_MD_FLAG_INVALIDATE	MD supports memory invalidation
UCT_MD_FLAG_EXPORTED_MKEY	MD supports exporting memory keys with another process using the same device or attaching to an exported memory key.
UCT_MD_FLAG_REG_DMABUF	MD supports registering a dmabuf file descriptor.

enum uct_md_mem_flags

Enumerator
UCT_MD_MEM_FLAG_NONBLOCK	Hint to perform non-blocking allocation/registration: page mapping may be deferred until it is accessed by the CPU or a transport.
UCT_MD_MEM_FLAG_FIXED	Place the mapping at exactly defined address.
UCT_MD_MEM_FLAG_LOCK	Registered memory should be locked. May incur extra cost for registration, but memory access is usually faster.
UCT_MD_MEM_FLAG_HIDE_ERRORS	Hide errors on memory registration. In some cases registration failure is not an error (e. g. for merged memory regions).
UCT_MD_MEM_ACCESS_REMOTE_PUT	Enable remote put access.
UCT_MD_MEM_ACCESS_REMOTE_GET	Enable remote get access.
UCT_MD_MEM_ACCESS_REMOTE_ATOMIC	Enable remote atomic access.
UCT_MD_MEM_ACCESS_LOCAL_READ	Enable local read access.
UCT_MD_MEM_ACCESS_LOCAL_WRITE	Enable local write access.
UCT_MD_MEM_ACCESS_ALL	Enable local and remote access for all operations.
UCT_MD_MEM_ACCESS_RMA	Enable local and remote access for put and get operations.

enum uct_mem_advice_t

Enumerator
UCT_MADV_NORMAL	No special treatment
UCT_MADV_WILLNEED	can be used on the memory mapped with UCT_MD_MEM_FLAG_NONBLOCK to speed up memory mapping and to avoid page faults when the memory is accessed for the first time.

enum uct_md_mem_attr_field

The enumeration allows specifying which fields in uct_md_mem_attr_t are present.

Enumerator
UCT_MD_MEM_ATTR_FIELD_MEM_TYPE	Indicate if memory type is populated. E.g. CPU/GPU
UCT_MD_MEM_ATTR_FIELD_SYS_DEV	Indicate if details of system device backing the pointer are populated. For example: GPU device, NUMA domain, etc.
UCT_MD_MEM_ATTR_FIELD_BASE_ADDRESS	Request base address of the allocation to which the buffer belongs.
UCT_MD_MEM_ATTR_FIELD_ALLOC_LENGTH	Request the whole length of the allocation to which the buffer belongs.
UCT_MD_MEM_ATTR_FIELD_DMABUF_FD	Request a cross-device dmabuf file descriptor that represents a memory region, and can be used to register the region with another memory domain.
UCT_MD_MEM_ATTR_FIELD_DMABUF_OFFSET	Request the offset of the provided virtual address relative to the beginning of its backing dmabuf region.

enum uct_mem_alloc_params_field_t

The enumeration allows specifying which fields in uct_mem_alloc_params_t are present.

Enumerator
UCT_MEM_ALLOC_PARAM_FIELD_FLAGS	Enables uct_mem_alloc_params_t::flags
UCT_MEM_ALLOC_PARAM_FIELD_ADDRESS	Enables uct_mem_alloc_params_t::address
UCT_MEM_ALLOC_PARAM_FIELD_MEM_TYPE	Enables uct_mem_alloc_params_t::mem_type
UCT_MEM_ALLOC_PARAM_FIELD_MDS	Enables uct_mem_alloc_params_t::mds
UCT_MEM_ALLOC_PARAM_FIELD_NAME	Enables uct_mem_alloc_params_t::name

Function Documentation

ucs_status_t uct_md_mem_query	(	uct_md_h	md,
		const void *	address,
		size_t	length,
		uct_md_mem_attr_t *	mem_attr
	)

Return attributes such as memory type, base address, allocation length, and system device for the given pointer of specific length.

Parameters

[in]	md	Memory domain to run the query on. This function returns an error if the md does not recognize the pointer.
[in]	address	The address of the pointer. Must be non-NULL else UCS_ERR_INVALID_PARAM error is returned.
[in]	length	Length of the memory region to examine. Must be nonzero else UCS_ERR_INVALID_PARAM error is returned.
[in,out]	mem_attr	If successful, filled with ptr attributes.

Returns

UCS_OK if at least one attribute is successfully queried otherwise an error code as defined by ucs_status_t is returned.

ucs_status_t uct_md_query	(	uct_md_h	md,
		uct_md_attr_t *	md_attr
	)

Parameters

[in]	md	Memory domain to query.
[out]	md_attr	Filled with memory domain attributes.

Examples:

uct_hello_world.c.

ucs_status_t uct_md_mem_advise	(	uct_md_h	md,
		uct_mem_h	memh,
		void *	addr,
		size_t	length,
		uct_mem_advice_t	advice
	)

This routine advises the UCT about how to handle memory range beginning at address and size of length bytes. This call does not influence the semantics of the application, but may influence its performance. The advice may be ignored.

Parameters

[in]	md	Memory domain memory was allocated or registered on.
[in]	memh	Memory handle, as returned from uct_mem_alloc
[in]	addr	Memory base address. Memory range must belong to the memh
[in]	length	Length of memory to advise. Must be >0.
[in]	advice	Memory use advice as defined in the uct_mem_advice_t list

ucs_status_t uct_md_mem_reg	(	uct_md_h	md,
		void *	address,
		size_t	length,
		unsigned	flags,
		uct_mem_h *	memh_p
	)

Register memory on the memory domain. In order to use this function, MD must support UCT_MD_FLAG_REG flag.

Parameters

[in]	md	Memory domain to register memory on.
[in]	address	Memory to register.
[in]	length	Size of memory to register. Must be >0.
[in]	flags	Memory allocation flags, see uct_md_mem_flags.
[out]	memh_p	Filled with handle for allocated region.

Examples:

uct_hello_world.c.

ucs_status_t uct_md_mem_dereg	(	uct_md_h	md,
		uct_mem_h	memh
	)

Parameters

[in]	md	Memory domain which was used to register the memory.
[in]	memh	Local access key to memory region.

Examples:

uct_hello_world.c.

ucs_status_t uct_md_detect_memory_type	(	uct_md_h	md,
		const void *	addr,
		size_t	length,
		ucs_memory_type_t *	mem_type_p
	)

Parameters

[in]	md	Memory domain to detect memory type
[in]	addr	Memory address to detect.
[in]	length	Size of memory
[out]	mem_type_p	Filled with memory type of the address range if function succeeds

Returns

UCS_OK If memory type is successfully detected UCS_ERR_INVALID_ADDR If failed to detect memory type

ucs_status_t uct_mem_alloc	(	size_t	length,
		const uct_alloc_method_t *	methods,
		unsigned	num_methods,
		const uct_mem_alloc_params_t *	params,
		uct_allocated_memory_t *	mem
	)

Allocate potentially registered memory.

Parameters

[in]	length	The minimal size to allocate. The actual size may be larger, for example because of alignment restrictions. Must be >0.
[in]	methods	Array of memory allocation methods to attempt. Each of the provided allocation methods will be tried in array order, to perform the allocation, until one succeeds. Whenever the MD method is encountered, each of the provided MDs will be tried in array order, to allocate the memory, until one succeeds, or they are exhausted. In this case the next allocation method from the initial list will be attempted.
[in]	num_methods	Length of 'methods' array.
[in]	params	Memory allocation characteristics, see uct_mem_alloc_params_t.
[out]	mem	In case of success, filled with information about the allocated memory. uct_allocated_memory_t

ucs_status_t uct_mem_free

(

const uct_allocated_memory_t *

mem

)

Release the memory allocated by uct_mem_alloc.

Parameters

[in]

mem

Description of allocated memory, as returned from uct_mem_alloc.

ucs_status_t uct_md_config_read	(	uct_component_h	component,
		const char *	env_prefix,
		const char *	filename,
		uct_md_config_t **	config_p
	)

Parameters

[in]	component	Read the configuration of this component.
[in]	env_prefix	If non-NULL, search for environment variables starting with this UCT_<prefix>_. Otherwise, search for environment variables starting with just UCT_.
[in]	filename	If non-NULL, read configuration from this file. If the file does not exist, it will be ignored.
[out]	config_p	Filled with a pointer to the configuration.

Returns

Error code.

Examples:

uct_hello_world.c.

int uct_md_is_sockaddr_accessible	(	uct_md_h	md,
		const ucs_sock_addr_t *	sockaddr,
		uct_sockaddr_accessibility_t	mode
	)

This function checks if a remote sock address can be accessed from a local memory domain. Accessibility can be checked in local or remote mode.

Parameters

[in]	md	Memory domain to check accessibility from. This memory domain must support the UCT_MD_FLAG_SOCKADDR flag.
[in]	sockaddr	Socket address to check accessibility to.
[in]	mode	Mode for checking accessibility, as defined in uct_sockaddr_accessibility_t. Indicates if accessibility is tested on the server side - for binding to the given sockaddr, or on the client side - for connecting to the given remote peer's sockaddr.

Returns

Nonzero if accessible, 0 if inaccessible.

ucs_status_t uct_md_mkey_pack	(	uct_md_h	md,
		uct_mem_h	memh,
		void *	rkey_buffer
	)

Parameters

[in]	md	Handle to memory domain.
[in]	memh	Local key, whose remote key should be packed.
[out]	rkey_buffer	Filled with packed remote key.

Returns

Error code.

ucs_status_t uct_rkey_unpack	(	uct_component_h	component,
		const void *	rkey_buffer,
		uct_rkey_bundle_t *	rkey_ob
	)

Parameters

[in]	component	Component on which to unpack the remote key.
[in]	rkey_buffer	Packed remote key buffer.
[out]	rkey_ob	Filled with the unpacked remote key and its type.

Note

The remote key must be unpacked with the same component that was used to pack it. For example, if a remote device address on the remote memory domain which was used to pack the key is reachable by a transport on a local component, then that component is eligible to unpack the key. If the remote key buffer cannot be unpacked with the given component, UCS_ERR_INVALID_PARAM will be returned.

Returns

Error code.

ucs_status_t uct_rkey_ptr	(	uct_component_h	component,
		uct_rkey_bundle_t *	rkey_ob,
		uint64_t	remote_addr,
		void **	addr_p
	)

This routine returns a local pointer to the remote memory described by the rkey bundle. The component must support UCT_COMPONENT_FLAG_RKEY_PTR flag.

Parameters

[in]	component	Component on which to obtain the pointer to the remote key.
[in]	rkey_ob	A remote key bundle as returned by the uct_rkey_unpack function.
[in]	remote_addr	A remote address within the memory area described by the rkey_ob.
[out]	addr_p	A pointer that can be used for direct access to the remote memory.

Note

The component used to obtain a local pointer to the remote memory must be the same component that was used to pack the remote key. See notes section for uct_rkey_unpack.

Returns

Error code if the remote memory cannot be accessed directly or the remote address is not valid.

ucs_status_t uct_rkey_release	(	uct_component_h	component,
		const uct_rkey_bundle_t *	rkey_ob
	)

Parameters

[in]	component	Component which was used to unpack the remote key.
[in]	rkey_ob	Remote key to release.