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man pages section 9: DDI and DKI Kernel Functions

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Updated: Thursday, June 13, 2019



kstat_create - create and initialize a new kstat


#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)



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


The provider's instance number, as from the ddi_get_instance() function. Modules which do not have a meaningful instance number should use 0. For more information, see the ddi_get_instance(9F) man page.


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


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.


The type of kstat to allocate. Valid types are:


Allows more than one data record per kstat.


Interrupt; only one data record per kstat.


I/O; only one data record per kstat


The number of type-specific data records to allocate.


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


Tells kstat_create() function 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.


Makes the kstat data section writable by root.


Indicates that this kstat is to be persistent over time. For persistent kstats, the kstat_delete() function simply marks the kstat as dormant, a subsequent kstat_create() function 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. For more information, see the kstat_delete(9F) man page.


The kstat_create() function is used in conjunction with the kstat_install() function to allocate and initialize a kstat(9S) structure. For more information, see the kstat_install(9F) man page. The method of allocation is generally as follows:

The kstat_create() function allocates and performs necessary system initialization of a kstat(9S) structure. The kstat_create() function 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 the 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, the kstat_install() function is used to make the kstat accessible to the outside world. For more information, see the kstat_install(9F) man page.

Return Values

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


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


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 */

See Also

kstat(3KSTAT), ddi_get_instance(9F), kstat_delete(9F), kstat_install(9F), kstat_named_init(9F), kstat(9S), kstat_named(9S), kstat2_create(9F), kstat2_delete(9F), kstat2_install(9F)

Writing Device Drivers in Oracle Solaris 11.4


The use of the kstat_create() function is deprecated. The function may be removed in a future release of Oracle Solaris. Use the kstat2_create() function instead. For more information, refer to the kstat2_create(9F) man page.