path: root/block/blk-throttle.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Interface for controlling IO bandwidth on a request queue
 *
 * Copyright (C) 2010 Vivek Goyal <vgoyal@redhat.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/blktrace_api.h>
#include "blk.h"
#include "blk-cgroup-rwstat.h"
#include "blk-stat.h"
#include "blk-throttle.h"

/* Max dispatch from a group in 1 round */
#define THROTL_GRP_QUANTUM 8

/* Total max dispatch from all groups in one round */
#define THROTL_QUANTUM 32

/* Throttling is performed over a slice and after that slice is renewed */
#define DFL_THROTL_SLICE_HD (HZ / 10)
#define DFL_THROTL_SLICE_SSD (HZ / 50)
#define MAX_THROTL_SLICE (HZ)

/* A workqueue to queue throttle related work */
static struct workqueue_struct *kthrotld_workqueue;

#define rb_entry_tg(node)	rb_entry((node), struct throtl_grp, rb_node)

struct