VMEM_CREATE(9F) Kernel Functions for Drivers VMEM_CREATE(9F)

NAME

vmem_create, vmem_xcreate, vmem_destroycreate and destroy vmem arenas

SYNOPSIS

#include <sys/vmem.h>
typedef struct vmem vmem_t;
typedef void *(vmem_alloc_t)(vmem_t *, size_t, int);
typedef void (vmem_free_t)(vmem_t *, void *, size_t);
typedef void *(vmem_ximport_t)(vmem_t *, size_t *, size_t, int);
vmem_t *
vmem_create(const char *name, void *base, size_t size, size_t quantum, vmem_alloc_t *afunc, vmem_free_t *ffunc, vmem_t *source, size_t qcache_max, int vmflag);
vmem_t *
vmem_xcreate(const char *name, void *base, size_t size, size_t quantum, vmem_ximport_t *afunc, vmem_free_t *ffunc, vmem_t *source, size_t qcache_max, int vmflag);
void
vmem_destroy(vmem_t *vmp);

INTERFACE LEVEL

illumos DDI specific

PARAMETERS

name
A character string giving a name to the vmem arena to be created.
base
An address indicating the lowest possible value in the arena.
size
The size of the arena to create
quantum
The arena's “quantum”. The granularity of the arena. The amount allocated at minimum by each request.
afunc
A function which is called to import new spans from source. Which may be NULL if this arena does not import from another.
ffunc
A function which is called to return spans to source. Which may be NULL if this arena does not import from another.
source
An arena from which this arena will import. Which may be NULL if this arena does not import from another.
qcache_max
Each arena offers caching of integer multiples of quantum up to qcache_max.
vmflag
A bitmask of flags indicating the characteristics of this arena.
VMC_IDENTIFIER
The arena represents arbitrary integer identifiers, rather than virtual memory.
vmp
A pointer to the vmem arena to be destroyed.

DESCRIPTION

A vmem arena is a section of an arbitrary address space (a range of integer addresses). This commonly represents virtual memory, but can in fact be an arbitrary set of integers. The VMC_IDENTIFIER flag set at arena creation time differentiates between these two cases.
The afunc, ffunc, and source arguments combine to support a hierarchical structure of arenas, each importing from a single parent (the source). The vmem_create() and vmem_xcreate() functions differ in that the latter provides an interface for afunc to alter the size of the span imported from source. It is only legal to increase thise size.

CONTEXT

These functions can be called from user or kernel context.

RETURN VALUES

Upon successful completion the vmem_create(and) vmem_xcreate() functions return a pointer to a vmem arena. Otherwise, NULL is returned to indicate the arena could not be created.

SEE ALSO

vmem(9), vmem_add(9F), vmem_alloc(9F)
January 18, 2017 illumos