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kstat_create (9)

>> kstat_create (9) ( Solaris man: Ядро )

NAME

kstat_create - create and initialize a new kstat

SYNOPSIS

#include <sys/types.h>
#include <sys/kstat.h>



kstat_t *kstat_create(const char *ks_module, int ks_instance, 
    const char *ks_name, const char *ks_class, uchar_t ks_type, 
    ulong_t ks_ndata, uchar_t ks_flag);

INTERFACE LEVEL

Solaris DDI specific (Solaris DDI)

PARAMETERS

ks_module

: The name of the provider's module (such as "sd", "esp", ...). The "core" kernel uses the name "unix".

ks_instance

: The provider's instance number, as from ddi_get_instance(9F). Modules which do not have a meaningful instance number should use 0.

ks_name

: A pointer to a string that uniquely identifies this structure. Only KSTAT_STRLEN - 1 characters are significant.

ks_class

: The general class that this kstat belongs to. The following classes are currently in use: disk, tape, net, controller, vm, kvm, hat, streams, kstat, and misc.

ks_type

The type of kstat to allocate. Valid types are:

KSTAT_TYPE_NAMED

: Allows more than one data record per kstat.

KSTAT_TYPE_INTR

: Interrupt; only one data record per kstat.

KSTAT_TYPE_IO

: I/O; only one data record per kstat

ks_ndata

: The number of type-specific data records to allocate.

ks_flag

A bit-field of various flags for this kstat. ks_flag is some combination of:

KSTAT_FLAG_VIRTUAL

: Tells kstat_create() not to allocate memory for the kstat data section; instead, the driver will set the ks_data field to point to the data it wishes to export. This provides a convenient way to export existing data structures.

KSTAT_FLAG_WRITABLE

: Makes the kstat data section writable by root.

KSTAT_FLAG_PERSISTENT

: Indicates that this kstat is to be persistent over time. For persistent kstats, kstat_delete(9F) simply marks the kstat as dormant; a subsequent kstat_create() reactivates the kstat. This feature is provided so that statistics are not lost across driver close/open (such as raw disk I/O on a disk with no mounted partitions.) Note: Persistent kstats cannot be virtual, since ks_data points to garbage as soon as the driver goes away.

DESCRIPTION

kstat_create() is used in conjunction with kstat_install(9F) to allocate and initialize a kstat(9S) structure. The method is generally as follows:

kstat_create() allocates and performs necessary system initialization of a kstat(9S) structure. kstat_create() allocates memory for the entire kstat (header plus data), initializes all header fields, initializes the data section to all zeroes, assigns a unique kstat ID (KID), and puts the kstat onto the system's kstat chain. The returned kstat is marked invalid because the provider (caller) has not yet had a chance to initialize the data section.

After a successful call to kstat_create() the driver must perform any necessary initialization of the data section (such as setting the name fields in a kstat of type KSTAT_TYPE_NAMED). Virtual kstats must have the ks_data field set at this time. The provider may also set the ks_update, ks_private, and ks_lock fields if necessary.

Once the kstat is completely initialized, kstat_install(9F) is used to make the kstat accessible to the outside world.

RETURN VALUES

If successful, kstat_create() returns a pointer to the allocated kstat. NULL is returned upon failure.

CONTEXT

kstat_create() can be called from user or kernel context.

EXAMPLES

Example 1 Allocating and Initializing a kstat Structure

pkstat_t   *ksp;
  ksp = kstat_create(module, instance, name, class, type, ndata, flags);
  if (ksp) {
     /* ... provider initialization, if necessary */
     kstat_install(ksp);
  }