Commit f382fb0b authored by Jens Axboe's avatar Jens Axboe

block: remove legacy IO schedulers

Retain the deadline documentation, as that carries over to mq-deadline
as well.
Tested-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 404b8f5a
This diff is collapsed.
......@@ -3,67 +3,6 @@ if BLOCK
menu "IO Schedulers"
config IOSCHED_NOOP
bool
default y
---help---
The no-op I/O scheduler is a minimal scheduler that does basic merging
and sorting. Its main uses include non-disk based block devices like
memory devices, and specialised software or hardware environments
that do their own scheduling and require only minimal assistance from
the kernel.
config IOSCHED_DEADLINE
tristate "Deadline I/O scheduler"
default y
---help---
The deadline I/O scheduler is simple and compact. It will provide
CSCAN service with FIFO expiration of requests, switching to
a new point in the service tree and doing a batch of IO from there
in case of expiry.
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
among all processes in the system. It should provide a fair
and low latency working environment, suitable for both desktop
and server systems.
This is the default I/O scheduler.
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP
---help---
Enable group IO scheduling in CFQ.
choice
prompt "Default I/O scheduler"
default DEFAULT_CFQ
help
Select the I/O scheduler which will be used by default for all
block devices.
config DEFAULT_DEADLINE
bool "Deadline" if IOSCHED_DEADLINE=y
config DEFAULT_CFQ
bool "CFQ" if IOSCHED_CFQ=y
config DEFAULT_NOOP
bool "No-op"
endchoice
config DEFAULT_IOSCHED
string
default "deadline" if DEFAULT_DEADLINE
default "cfq" if DEFAULT_CFQ
default "noop" if DEFAULT_NOOP
config MQ_IOSCHED_DEADLINE
tristate "MQ deadline I/O scheduler"
default y
......
......@@ -18,9 +18,6 @@ obj-$(CONFIG_BLK_DEV_BSGLIB) += bsg-lib.o
obj-$(CONFIG_BLK_CGROUP) += blk-cgroup.o
obj-$(CONFIG_BLK_DEV_THROTTLING) += blk-throttle.o
obj-$(CONFIG_BLK_CGROUP_IOLATENCY) += blk-iolatency.o
obj-$(CONFIG_IOSCHED_NOOP) += noop-iosched.o
obj-$(CONFIG_IOSCHED_DEADLINE) += deadline-iosched.o
obj-$(CONFIG_IOSCHED_CFQ) += cfq-iosched.o
obj-$(CONFIG_MQ_IOSCHED_DEADLINE) += mq-deadline.o
obj-$(CONFIG_MQ_IOSCHED_KYBER) += kyber-iosched.o
bfq-y := bfq-iosched.o bfq-wf2q.o bfq-cgroup.o
......
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......@@ -225,8 +225,6 @@ int elevator_init(struct request_queue *q)
chosen_elevator);
}
if (!e)
e = elevator_get(q, CONFIG_DEFAULT_IOSCHED, false);
if (!e) {
printk(KERN_ERR
"Default I/O scheduler not found. Using noop.\n");
......@@ -356,68 +354,6 @@ struct request *elv_rb_find(struct rb_root *root, sector_t sector)
}
EXPORT_SYMBOL(elv_rb_find);
/*
* Insert rq into dispatch queue of q. Queue lock must be held on
* entry. rq is sort instead into the dispatch queue. To be used by
* specific elevators.
*/
void elv_dispatch_sort(struct request_queue *q, struct request *rq)
{
sector_t boundary;
struct list_head *entry;
if (q->last_merge == rq)
q->last_merge = NULL;
elv_rqhash_del(q, rq);
q->nr_sorted--;
boundary = q->end_sector;
list_for_each_prev(entry, &q->queue_head) {
struct request *pos = list_entry_rq(entry);
if (req_op(rq) != req_op(pos))
break;
if (rq_data_dir(rq) != rq_data_dir(pos))
break;
if (pos->rq_flags & (RQF_STARTED | RQF_SOFTBARRIER))
break;
if (blk_rq_pos(rq) >= boundary) {
if (blk_rq_pos(pos) < boundary)
continue;
} else {
if (blk_rq_pos(pos) >= boundary)
break;
}
if (blk_rq_pos(rq) >= blk_rq_pos(pos))
break;
}
list_add(&rq->queuelist, entry);
}
EXPORT_SYMBOL(elv_dispatch_sort);
/*
* Insert rq into dispatch queue of q. Queue lock must be held on
* entry. rq is added to the back of the dispatch queue. To be used by
* specific elevators.
*/
void elv_dispatch_add_tail(struct request_queue *q, struct request *rq)
{
if (q->last_merge == rq)
q->last_merge = NULL;
elv_rqhash_del(q, rq);
q->nr_sorted--;
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
list_add_tail(&rq->queuelist, &q->queue_head);
}
EXPORT_SYMBOL(elv_dispatch_add_tail);
enum elv_merge elv_merge(struct request_queue *q, struct request **req,
struct bio *bio)
{
......@@ -881,12 +817,6 @@ int elv_register(struct elevator_type *e)
list_add_tail(&e->list, &elv_list);
spin_unlock(&elv_list_lock);
/* print pretty message */
if (elevator_match(e, chosen_elevator) ||
(!*chosen_elevator &&
elevator_match(e, CONFIG_DEFAULT_IOSCHED)))
def = " (default)";
printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
def);
return 0;
......
/*
* elevator noop
*/
#include <linux/blkdev.h>
#include <linux/elevator.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
struct noop_data {
struct list_head queue;
};
static void noop_merged_requests(struct request_queue *q, struct request *rq,
struct request *next)
{
list_del_init(&next->queuelist);
}
static int noop_dispatch(struct request_queue *q, int force)
{
struct noop_data *nd = q->elevator->elevator_data;
struct request *rq;
rq = list_first_entry_or_null(&nd->queue, struct request, queuelist);
if (rq) {
list_del_init(&rq->queuelist);
elv_dispatch_sort(q, rq);
return 1;
}
return 0;
}
static void noop_add_request(struct request_queue *q, struct request *rq)
{
struct noop_data *nd = q->elevator->elevator_data;
list_add_tail(&rq->queuelist, &nd->queue);
}
static struct request *
noop_former_request(struct request_queue *q, struct request *rq)
{
struct noop_data *nd = q->elevator->elevator_data;
if (rq->queuelist.prev == &nd->queue)
return NULL;
return list_prev_entry(rq, queuelist);
}
static struct request *
noop_latter_request(struct request_queue *q, struct request *rq)
{
struct noop_data *nd = q->elevator->elevator_data;
if (rq->queuelist.next == &nd->queue)
return NULL;
return list_next_entry(rq, queuelist);
}
static int noop_init_queue(struct request_queue *q, struct elevator_type *e)
{
struct noop_data *nd;
struct elevator_queue *eq;
eq = elevator_alloc(q, e);
if (!eq)
return -ENOMEM;
nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node);
if (!nd) {
kobject_put(&eq->kobj);
return -ENOMEM;
}
eq->elevator_data = nd;
INIT_LIST_HEAD(&nd->queue);
spin_lock_irq(q->queue_lock);
q->elevator = eq;
spin_unlock_irq(q->queue_lock);
return 0;
}
static void noop_exit_queue(struct elevator_queue *e)
{
struct noop_data *nd = e->elevator_data;
BUG_ON(!list_empty(&nd->queue));
kfree(nd);
}
static struct elevator_type elevator_noop = {
.ops.sq = {
.elevator_merge_req_fn = noop_merged_requests,
.elevator_dispatch_fn = noop_dispatch,
.elevator_add_req_fn = noop_add_request,
.elevator_former_req_fn = noop_former_request,
.elevator_latter_req_fn = noop_latter_request,
.elevator_init_fn = noop_init_queue,
.elevator_exit_fn = noop_exit_queue,
},
.elevator_name = "noop",
.elevator_owner = THIS_MODULE,
};
static int __init noop_init(void)
{
return elv_register(&elevator_noop);
}
static void __exit noop_exit(void)
{
elv_unregister(&elevator_noop);
}
module_init(noop_init);
module_exit(noop_exit);
MODULE_AUTHOR("Jens Axboe");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("No-op IO scheduler");
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