[PATCH 08/13] blk-iocost: make iocost pluggable and modular
From: Wang Jianchao
Date: Mon Jan 10 2022 - 04:13:14 EST
From: Wang Jianchao <wangjianchao@xxxxxxxxxxxx>
Make blk-iocost pluggable and modular. Then we can close or open
it through /sys/block/xxx/queue/qos and rmmod the module if we don't
need it which can release one blkcg policy slot.
Signed-off-by: Wang Jianchao <wangjianchao@xxxxxxxxxxxx>
---
block/Kconfig | 2 +-
block/Makefile | 4 ++--
block/blk-iocost.c | 53 ++++++++++++++++++++++++++----------------
block/blk-mq-debugfs.c | 2 --
block/blk-rq-qos.h | 1 -
5 files changed, 36 insertions(+), 26 deletions(-)
diff --git a/block/Kconfig b/block/Kconfig
index e1b1bff5c1e9..3e1a3487b55a 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -134,7 +134,7 @@ config BLK_CGROUP_FC_APPID
application specific identification into the FC frame.
config BLK_CGROUP_IOCOST
- bool "Enable support for cost model based cgroup IO controller"
+ tristate "Enable support for cost model based cgroup IO controller"
depends on BLK_CGROUP
select BLK_RQ_ALLOC_TIME
select BLK_BIO_IOCOST
diff --git a/block/Makefile b/block/Makefile
index ccf61c57e1d4..8950913cbcc9 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -20,8 +20,8 @@ obj-$(CONFIG_BLK_DEV_THROTTLING) += blk-throttle.o
obj-$(CONFIG_BLK_CGROUP_IOPRIO) += blk-ioprio.o
iolat-y := blk-iolatency.o
obj-$(CONFIG_BLK_CGROUP_IOLATENCY) += iolat.o
-
-obj-$(CONFIG_BLK_CGROUP_IOCOST) += blk-iocost.o
+iocost-y := blk-iocost.o
+obj-$(CONFIG_BLK_CGROUP_IOCOST) += iocost.o
obj-$(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
diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index cfc0e305c32e..afa52354d42b 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -660,9 +660,10 @@ static struct ioc *rqos_to_ioc(struct rq_qos *rqos)
return container_of(rqos, struct ioc, rqos);
}
+static struct rq_qos_ops ioc_rqos_ops;
static struct ioc *q_to_ioc(struct request_queue *q)
{
- return rqos_to_ioc(rq_qos_by_id(q, RQ_QOS_COST));
+ return rqos_to_ioc(rq_qos_by_id(q, ioc_rqos_ops.id));
}
static const char *q_name(struct request_queue *q)
@@ -2810,6 +2811,7 @@ static void ioc_rqos_exit(struct rq_qos *rqos)
struct ioc *ioc = rqos_to_ioc(rqos);
blkcg_deactivate_policy(rqos->q, &blkcg_policy_iocost);
+ rq_qos_deactivate(rqos);
spin_lock_irq(&ioc->lock);
ioc->running = IOC_STOP;
@@ -2820,13 +2822,20 @@ static void ioc_rqos_exit(struct rq_qos *rqos)
kfree(ioc);
}
+static int blk_iocost_init(struct request_queue *q);
static struct rq_qos_ops ioc_rqos_ops = {
+#if IS_MODULE(CONFIG_BLK_CGROUP_IOCOST)
+ .owner = THIS_MODULE,
+#endif
+ .name = "iocost",
+ .flags = RQOS_FLAG_CGRP_POL | RQOS_FLAG_RQ_ALLOC_TIME,
.throttle = ioc_rqos_throttle,
.merge = ioc_rqos_merge,
.done_bio = ioc_rqos_done_bio,
.done = ioc_rqos_done,
.queue_depth_changed = ioc_rqos_queue_depth_changed,
.exit = ioc_rqos_exit,
+ .init = blk_iocost_init,
};
static int blk_iocost_init(struct request_queue *q)
@@ -2856,10 +2865,7 @@ static int blk_iocost_init(struct request_queue *q)
}
rqos = &ioc->rqos;
- rqos->id = RQ_QOS_COST;
- rqos->ops = &ioc_rqos_ops;
- rqos->q = q;
-
+ rq_qos_activate(q, rqos, &ioc_rqos_ops);
spin_lock_init(&ioc->lock);
timer_setup(&ioc->timer, ioc_timer_fn, 0);
INIT_LIST_HEAD(&ioc->active_iocgs);
@@ -2883,10 +2889,9 @@ static int blk_iocost_init(struct request_queue *q)
* called before policy activation completion, can't assume that the
* target bio has an iocg associated and need to test for NULL iocg.
*/
- rq_qos_add(q, rqos);
ret = blkcg_activate_policy(q, &blkcg_policy_iocost);
if (ret) {
- rq_qos_del(q, rqos);
+ rq_qos_deactivate(rqos);
free_percpu(ioc->pcpu_stat);
kfree(ioc);
return ret;
@@ -3173,12 +3178,10 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
if (IS_ERR(bdev))
return PTR_ERR(bdev);
- rqos = rq_qos_get(bdev_get_queue(bdev), RQ_QOS_COST);
+ rqos = rq_qos_get(bdev_get_queue(bdev), ioc_rqos_ops.id);
if (!rqos) {
- ret = blk_iocost_init(bdev_get_queue(bdev));
- if (ret)
- goto err;
- rqos = rq_qos_get(bdev_get_queue(bdev), RQ_QOS_COST);
+ ret = -EOPNOTSUPP;
+ goto err;
}
ioc = rqos_to_ioc(rqos);
@@ -3257,10 +3260,8 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input,
if (enable) {
blk_stat_enable_accounting(ioc->rqos.q);
- blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q);
ioc->enabled = true;
} else {
- blk_queue_flag_clear(QUEUE_FLAG_RQ_ALLOC_TIME, ioc->rqos.q);
ioc->enabled = false;
}
@@ -3344,12 +3345,10 @@ static ssize_t ioc_cost_model_write(struct kernfs_open_file *of, char *input,
if (IS_ERR(bdev))
return PTR_ERR(bdev);
- rqos = rq_qos_get(bdev_get_queue(bdev), RQ_QOS_COST);
+ rqos = rq_qos_get(bdev_get_queue(bdev), ioc_rqos_ops.id);
if (!ioc) {
- ret = blk_iocost_init(bdev_get_queue(bdev));
- if (ret)
- goto err;
- rqos = rq_qos_get(bdev_get_queue(bdev), RQ_QOS_COST);
+ ret = -EOPNOTSUPP;
+ goto err;
}
ioc = rqos_to_ioc(rqos);
@@ -3449,13 +3448,27 @@ static struct blkcg_policy blkcg_policy_iocost = {
static int __init ioc_init(void)
{
- return blkcg_policy_register(&blkcg_policy_iocost);
+ int ret;
+
+ ret = rq_qos_register(&ioc_rqos_ops);
+ if (ret)
+ return ret;
+
+ ret = blkcg_policy_register(&blkcg_policy_iocost);
+ if (ret)
+ rq_qos_unregister(&ioc_rqos_ops);
+
+ return ret;
}
static void __exit ioc_exit(void)
{
blkcg_policy_unregister(&blkcg_policy_iocost);
+ rq_qos_unregister(&ioc_rqos_ops);
}
module_init(ioc_init);
module_exit(ioc_exit);
+MODULE_AUTHOR("Tejun Heo");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Cost model based cgroup IO controller");
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 57c33f4730f2..14fda9a5e552 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -820,8 +820,6 @@ void blk_mq_debugfs_unregister_sched(struct request_queue *q)
static const char *rq_qos_id_to_name(enum rq_qos_id id)
{
switch (id) {
- case RQ_QOS_COST:
- return "cost";
case RQ_QOS_IOPRIO:
return "ioprio";
}
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 6ca46c69e325..4eef53f2c290 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -14,7 +14,6 @@
struct blk_mq_debugfs_attr;
enum rq_qos_id {
- RQ_QOS_COST,
RQ_QOS_IOPRIO,
};
--
2.17.1