^^&&^^

Edit File: ioscheduler.stp

// IO scheduler tapset
// Copyright (C) 2005, 2006 IBM Corp.
// Copyright (C) 2010-2017 Red Hat Inc.
//
// This file is part of systemtap, and is free software.  You can
// redistribute it and/or modify it under the terms of the GNU General
// Public License (GPL); either version 2, or (at your option) any
// later version.
// <tapsetdescription>
// This family of probe points is used to probe IO scheduler activities. 
// </tapsetdescription>
%{
#include <linux/blkdev.h>
#include <linux/elevator.h>
%}

/**
 * probe ioscheduler.elv_next_request - Fires when a request is retrieved from the request queue
 * @name: Name of the probe point
 * @elevator_name: The type of I/O elevator currently enabled
 */
probe ioscheduler.elv_next_request = kernel.function("blk_peek_request") !,
				     kernel.function("elv_next_request")
{
	name = "elv_next_request"
	elevator_name = kernel_string(
		@choose_defined($q->elevator->type->elevator_name,
			@choose_defined($q->elevator->elevator_type->elevator_name,
                                        $q->elevator->elevator_name)), "")
}

/**
 * probe ioscheduler.elv_next_request.return - Fires when a request retrieval issues a return signal
 * @name: Name of the probe point
 * @rq: Address of the request
 * @rq_flags: Request flags
 * @disk_major: Disk major number of the request
 * @disk_minor: Disk minor number of the request
 */
probe ioscheduler.elv_next_request.return =
		kernel.function("blk_peek_request").return !,
		kernel.function("elv_next_request").return
{
	name = "elv_next_request"
	if ($return == 0)  {
		rq = 0
		rq_flags = 0
		disk_major = -1
		disk_minor = -1
	} else {
		rq = $return
		rq_flags = @choose_defined($return->cmd_flags, $return->flags)
		if ($return->rq_disk == 0)  {
			disk_major = -1
			disk_minor = -1
		} else {
			disk_major = $return->rq_disk->major
			disk_minor = $return->rq_disk->first_minor
		}
	}
}

/**
 * probe ioscheduler.elv_completed_request - Fires when a request is completed
 * @name: Name of the probe point
 * @elevator_name: The type of I/O elevator currently enabled
 * @rq: Address of the request
 * @rq_flags: Request flags
 * @disk_major: Disk major number of the request
 * @disk_minor: Disk minor number of the request
 */
probe ioscheduler.elv_completed_request
	= kernel.function("elv_completed_request")
{
	name = "elv_completed_request"
	elevator_name = kernel_string(
		@choose_defined($q->elevator->type->elevator_name,
			@choose_defined($q->elevator->elevator_type->elevator_name,
                                        $q->elevator->elevator_name)), "")
	if($rq == 0)  {
		disk_major = -1
		disk_minor = -1
	} else {
		if($rq->rq_disk == 0)  {
			disk_major = -1
			disk_minor = -1
		} else {
			disk_major = $rq->rq_disk->major
			disk_minor = $rq->rq_disk->first_minor
		}
	}

rq = $rq
	rq_flags = ($rq == 0) ? 0
		: @choose_defined($rq->cmd_flags, $rq->flags)
}

/**
 * probe ioscheduler.elv_add_request.kp - kprobe based probe to indicate that a request was added to the request queue
 * @name: Name of the probe point
 * @elevator_name: The type of I/O elevator currently enabled
 * @q: pointer to request queue
 * @rq: Address of the request
 * @rq_flags: Request flags
 * @disk_major: Disk major number of the request
 * @disk_minor: Disk minor number of the request
 */
// when a request is added to the request queue
probe ioscheduler.elv_add_request.kp =
		kernel.function("elv_insert") !,
		kernel.function("__elv_add_request")
{
	name = "elv_add_request"
	elevator_name = kernel_string(
		@choose_defined($q->elevator->type->elevator_name,
			@choose_defined($q->elevator->elevator_type->elevator_name,
                                        $q->elevator->elevator_name)), "")
	q = $q
	if($rq == 0)  {
		disk_major = -1
		disk_minor = -1
	} else {
		if($rq->rq_disk == 0)  {
			disk_major = -1
			disk_minor = -1
		} else {
			disk_major = $rq->rq_disk->major
			disk_minor = $rq->rq_disk->first_minor
		}
	}

rq = $rq
	rq_flags = ($rq == 0) ? 0
		: @choose_defined($rq->cmd_flags, $rq->flags)
}

/**
 * probe ioscheduler.elv_add_request.tp - tracepoint based probe to indicate a request is added to the request queue.
 * @name		: Name of the probe point
 * @elevator_name	: The type of I/O elevator currently enabled.
 * @q			: Pointer to request queue.
 * @rq			: Address of request.
 * @rq_flags		: Request flags.
 * @disk_major		: Disk major no of request.
 * @disk_minor		: Disk minor number of request.
 *
 */
probe ioscheduler.elv_add_request.tp = kernel.trace("block_rq_insert") ?
{
	name = "elv_add_request"
	q =  $q
	elevator_name = ($q->elevator == 0) ? "" : kernel_string(
		@choose_defined($q->elevator->type->elevator_name,
			@choose_defined($q->elevator->elevator_type->elevator_name,
                                        $q->elevator->elevator_name)), "")
	rq = $rq