iostdel Kernel Service

Purpose

Removes the registration of an I/O statistics structure that is used for maintaining I/O statistics on a particular device.

Syntax

#include <sys/types.h>
#include <sys/errno.h>
#include <sys/iostat.h>
void iostdel ( devstatp)
union {
        struct ttystat *ttystp;
        struct dkstat  *dkstp;
      } devstatp;

Description

The iostdel kernel service removes the registration of an I/O statistics structure for a terminating device. The device's ttystat or dkstat structure must be previously registered by using the iostadd kernel service. Following a return from the iostdel service, the iostat command no longer displays statistics for the device that is terminated.

The iostdel kernel service supports Multi-Path I/O (MPIO). For an MPIO device, the anchor is the disk's dkstat structure. An anchor (disk) might have several paths that are associated with it. Each of these paths can have a dkstat structure that is registered by using the iostadd kernel service. The semantics for unregistering a dkstat structure for an MPIO device are more restrictive than for a non-MPIO device. All paths must unregister before the anchor (disk) is unregistered. If the anchor (disk) dkstat structure is unregistered before all of the paths that are associated with it are unregistered, the iostdel kernel service removes the registration of the anchor (disk) dkstat structure and all remaining registered paths.

Parameters

Item Description
devstatp Points to an I/O statistics structure previously registered by using the iostadd kernel service.

On a platform that supports storage keys, the passed in devstatp parameter must be in the KKEY_PUBLIC or KKEY_BLOCK_DEV protection domain.

Execution Environment

The iostdel kernel service can be called from the process environment only.

Return Values

The iostdel service has no return values.