From d34849913819a5e0cbfbe724dbe79df89278c524 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Fri, 13 Jan 2017 14:43:58 -0700
Subject: [PATCH] blk-mq-sched: allow setting of default IO scheduler
Add Kconfig entries to manage what devices get assigned an MQ
scheduler, and add a blk-mq flag for drivers to opt out of scheduling.
The latter is useful for admin type queues that still allocate a blk-mq
queue and tag set, but aren't use for normal IO.
Signed-off-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
---
block/Kconfig.iosched | 56 ++++++++++++++++++++++++++++++++++++-----
block/blk-mq-sched.c | 20 +++++++++++++++
block/blk-mq-sched.h | 2 ++
block/blk-mq.c | 8 ++++++
block/elevator.c | 8 +++++-
drivers/nvme/host/pci.c | 1 +
include/linux/blk-mq.h | 1 +
7 files changed, 89 insertions(+), 7 deletions(-)
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 490ef2850faee..0715ce93daef4 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -32,12 +32,6 @@ config IOSCHED_CFQ
This is the default I/O scheduler.
-config MQ_IOSCHED_DEADLINE
- tristate "MQ deadline I/O scheduler"
- default y
- ---help---
- MQ version of the deadline IO scheduler.
-
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP
@@ -69,6 +63,56 @@ config DEFAULT_IOSCHED
default "cfq" if DEFAULT_CFQ
default "noop" if DEFAULT_NOOP
+config MQ_IOSCHED_DEADLINE
+ tristate "MQ deadline I/O scheduler"
+ default y
+ ---help---
+ MQ version of the deadline IO scheduler.
+
+config MQ_IOSCHED_NONE
+ bool
+ default y
+
+choice
+ prompt "Default single-queue blk-mq I/O scheduler"
+ default DEFAULT_SQ_NONE
+ help
+ Select the I/O scheduler which will be used by default for blk-mq
+ managed block devices with a single queue.
+
+ config DEFAULT_SQ_DEADLINE
+ bool "MQ Deadline" if MQ_IOSCHED_DEADLINE=y
+
+ config DEFAULT_SQ_NONE
+ bool "None"
+
+endchoice
+
+config DEFAULT_SQ_IOSCHED
+ string
+ default "mq-deadline" if DEFAULT_SQ_DEADLINE
+ default "none" if DEFAULT_SQ_NONE
+
+choice
+ prompt "Default multi-queue blk-mq I/O scheduler"
+ default DEFAULT_MQ_NONE
+ help
+ Select the I/O scheduler which will be used by default for blk-mq
+ managed block devices with multiple queues.
+
+ config DEFAULT_MQ_DEADLINE
+ bool "MQ Deadline" if MQ_IOSCHED_DEADLINE=y
+
+ config DEFAULT_MQ_NONE
+ bool "None"
+
+endchoice
+
+config DEFAULT_MQ_IOSCHED
+ string
+ default "mq-deadline" if DEFAULT_MQ_DEADLINE
+ default "none" if DEFAULT_MQ_NONE
+
endmenu
endif
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 26759798a0b39..d05061f27bb1f 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -366,3 +366,23 @@ void blk_mq_sched_teardown(struct request_queue *q)
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_sched_free_tags(set, hctx, i);
}
+
+int blk_mq_sched_init(struct request_queue *q)
+{
+ int ret;
+
+#if defined(CONFIG_DEFAULT_SQ_NONE)
+ if (q->nr_hw_queues == 1)
+ return 0;
+#endif
+#if defined(CONFIG_DEFAULT_MQ_NONE)
+ if (q->nr_hw_queues > 1)
+ return 0;
+#endif
+
+ mutex_lock(&q->sysfs_lock);
+ ret = elevator_init(q, NULL);
+ mutex_unlock(&q->sysfs_lock);
+
+ return ret;
+}
diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h
index 35c49e2e008a2..6b465bc7014c3 100644
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -28,6 +28,8 @@ void blk_mq_sched_move_to_dispatch(struct blk_mq_hw_ctx *hctx,
int blk_mq_sched_setup(struct request_queue *q);
void blk_mq_sched_teardown(struct request_queue *q);
+int blk_mq_sched_init(struct request_queue *q);
+
static inline bool
blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
{
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 45e1707a9f865..fa1f8619bfe7d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2285,6 +2285,14 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
mutex_unlock(&all_q_mutex);
put_online_cpus();
+ if (!(set->flags & BLK_MQ_F_NO_SCHED)) {
+ int ret;
+
+ ret = blk_mq_sched_init(q);
+ if (ret)
+ return ERR_PTR(ret);
+ }
+
return q;
err_hctxs:
diff --git a/block/elevator.c b/block/elevator.c
index 0e1ccddab8a26..bcba2dd5cb5c0 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -219,7 +219,13 @@ int elevator_init(struct request_queue *q, char *name)
}
if (!e) {
- e = elevator_get(CONFIG_DEFAULT_IOSCHED, false);
+ if (q->mq_ops && q->nr_hw_queues == 1)
+ e = elevator_get(CONFIG_DEFAULT_SQ_IOSCHED, false);
+ else if (q->mq_ops)
+ e = elevator_get(CONFIG_DEFAULT_MQ_IOSCHED, false);
+ else
+ e = elevator_get(CONFIG_DEFAULT_IOSCHED, false);
+
if (!e) {
printk(KERN_ERR
"Default I/O scheduler not found. " \
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 19beeb7b2ac26..e1b4e603b1cf7 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1181,6 +1181,7 @@ static int nvme_alloc_admin_tags(struct nvme_dev *dev)
dev->admin_tagset.timeout = ADMIN_TIMEOUT;
dev->admin_tagset.numa_node = dev_to_node(dev->dev);
dev->admin_tagset.cmd_size = nvme_cmd_size(dev);
+ dev->admin_tagset.flags = BLK_MQ_F_NO_SCHED;
dev->admin_tagset.driver_data = dev;
if (blk_mq_alloc_tag_set(&dev->admin_tagset))
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 63569eb46d150..8e4df3d6c8cd9 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -153,6 +153,7 @@ enum {
BLK_MQ_F_SG_MERGE = 1 << 2,
BLK_MQ_F_DEFER_ISSUE = 1 << 4,
BLK_MQ_F_BLOCKING = 1 << 5,
+ BLK_MQ_F_NO_SCHED = 1 << 6,
BLK_MQ_F_ALLOC_POLICY_START_BIT = 8,
BLK_MQ_F_ALLOC_POLICY_BITS = 1,
--
2.30.2