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authorJens Axboe <axboe@fb.com>2017-01-13 14:43:58 -0700
committerJens Axboe <axboe@fb.com>2017-01-17 10:04:31 -0700
commitd34849913819a5e0cbfbe724dbe79df89278c524 (patch)
tree71b427fa3b22b30dc2038448ec06936018adaee4
parent945ffb60c11dfb228130f3f2bdde961cecb76671 (diff)
downloadlinux-0-day-d34849913819a5e0cbfbe724dbe79df89278c524.tar.gz
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>
-rw-r--r--block/Kconfig.iosched56
-rw-r--r--block/blk-mq-sched.c20
-rw-r--r--block/blk-mq-sched.h2
-rw-r--r--block/blk-mq.c8
-rw-r--r--block/elevator.c8
-rw-r--r--drivers/nvme/host/pci.c1
-rw-r--r--include/linux/blk-mq.h1
7 files changed, 89 insertions, 7 deletions
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 490ef28..0715ce9 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 2675979..d05061f 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 35c49e2..6b465bc 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 45e1707..fa1f861 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 0e1ccdd..bcba2dd 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 19beeb7..e1b4e60 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 63569eb..8e4df3d 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,