Проект OpenNet: MAN rsm_memseg_export_create (3) Библиотечные вызовы (FreeBSD и Linux)

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rsm_memseg_export_create (3)

>> rsm_memseg_export_create (3) ( Solaris man: Библиотечные вызовы )

NAME

rsm_memseg_export_create, rsm_memseg_export_destroy, rsm_memseg_export_rebind - resource allocation and management functions for export memory segments

SYNOPSIS

cc [ flag... ] file... -lrsm [ library... ]
#include <rsmapi.h> 

int rsm_memseg_export_create(
    rsmapi_controller_handle_t controller,
    rsm_memseg_export_handle_t *memseg, void *vaddr,
    size_t length, uint_t flags);

int rsm_memseg_export_destroy(
    rsm_memseg_export_handle_t memseg);

int rsm_memseg_export_rebind(
    rsm_memseg_export_handle_t memseg,
    void *vaddr, offset_t off, size_t length);

DESCRIPTION

The rsm_memseg_export_create(), rsm_memseg_export_destroy(), and rsm_memseg_export_rebind() functions provide for allocation and management of resources supporting export memory segments. Exporting a memory segment involves the application allocating memory in its virtual address space through the System V shared memory interface or normal operating system memory allocation functions. This is followed by the calls to create the export segment and bind physical pages to back to allocated virtual address space.

The rsm_memseg_export_create() creates a new memory segment. Physical memory pages are allocated and are associated with the segment. The segment lifetime is the same as the lifetime of the creating process or until a destroy operation is performed. The controller argument is the controller handle obtained from a prior call to rsm_get_controller(3RSM). The export memory segment handle is obtained through the memseg argument for use in subsequent operations. The vaddr argument specifies the process virtual address for the segment. It must be aligned according to the controller page size attribute. The length argument specifies the size of the segment in bytes and must be in multiples of the controller page size. The flags argument is a bitmask of flags. Possible values are:

RSM_ALLOW_REBIND

: Unbind and rebind is allowed on the segment during its lifetime.

RSM_CREATE_SEG_DONTWAIT

: The RSMAPI segment create operations rsm_memseg_export_create() and rsm_memseg_export_publish(3RSM) should not block for resources and return RSMERR_INSUFFICIENT_RESOURCES to indicate resource shortage.

RSM_LOCK_OPS

: This segment can be used for lock operations.

The rsm_memseg_export_destroy() function deallocates the physical memory pages associated with the segment and disconnects all importers of the segment. The memseg argument is the export memory segment handle obtained by a call to rsm_memseg_export_create().

The rsm_memseg_export_rebind() function releases the current backing pages associated with the segment and allocates new physical memory pages. This operation is transparent to the importers of the segment. It is the responsibility of the application to prevent data access to the export segment until the rebind operation has completed. Segment data access during rebind does not cause a system failure but data content results are undefined. The memseg argument is the export segment handle pointer obtained from rsm_memseg_export_create(). The vaddr argument must be aligned with respect to the page size attribute of the controller. The length argument modulo controller page size must be 0. The off argument is currently unused.

RETURN VALUES

Upon successful completion, these functions return 0. Otherwise, an error value is returned to indicate the error.

ERRORS

The rsm_memseg_export_create(), rsm_memseg_export_destroy(), and rsm_memseg_export_rebind() functions can return the following errors:

RSMERR_BAD_SEG_HNDL

: Invalid segment handle.

The rsm_memseg_export_create() and rsm_memseg_export_rebind() functions can return the following errors:

RSMERR_BAD_CTLR_HNDL

: Invalid controller handle.

RSMERR_CTLR_NOT_PRESENT

: Controller not present.

RSMERR_BAD_LENGTH

: Length zero or length exceeds controller limits.

RSMERR_BAD_ADDR

: Invalid address.

RSMERR_INSUFFICIENT_MEM

: Insufficient memory.

RSMERR_INSUFFICIENT_RESOURCES

: Insufficient resources.

RSMERR_PERM_DENIED

: Permission denied.

RSMERR_NOT_CREATOR

: Not creator of segment.

RSMERR_REBIND_NOT_ALLOWED

: Rebind not allowed.

The rsm_memseg_export_create() function can return the following errors:

RSMERR_BAD_MEM_ALIGNMENT

: The address is not aligned on a page boundary.

The rsm_memseg_export_rebind() function can return the following errors:

RSMERR_INTERRUPTED

: The operation was interrupted by a signal.

The rsm_memseg_export_destroy() function can return the following errors:

RSMERR_POLLFD_IN_USE

: Poll file descriptor in use.

USAGE

Exporting a memory segment involves the application allocating memory in its virtual address space through the System V Shared Memory interface or other normal operating system memory allocation methods such as valloc() ( see malloc(3C)) or mmap(2). Memory for a file mapped with mmap() must be mapped MAP_PRIVATE.