blk-mq-sched: allow setting of default IO scheduler

Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 490ef2850faee1f6682e112a7876c35340794502..00502a3d76b756a223c9e2ba9ae9d9abbc0c8466 100644 (file)
--- 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 +63,43 @@ 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 MQ I/O scheduler"
+       default MQ_IOSCHED_NONE
+       help
+         Select the I/O scheduler which will be used by default for all
+         blk-mq managed block devices.
+
+       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
 
+config MQ_IOSCHED_ONLY_SQ
+       bool "Enable blk-mq IO scheduler only for single queue devices"
+       default y
+       help
+         Say Y here, if you only want to enable IO scheduling on block
+         devices that have a single queue registered.
+
 endif

diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 9213366e67d165a91afb28bef06a45ec827d2602..bcab84d325c2c7a7a65b66fc6008b716cf0465c3 100644 (file)
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -244,3 +244,22 @@ void __blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
 
        blk_mq_dispatch_rq_list(hctx, &rq_list);
 }
+
+int blk_mq_sched_init(struct request_queue *q)
+{
+       int ret;
+
+#if defined(CONFIG_DEFAULT_MQ_NONE)
+       return 0;
+#endif
+#if defined(CONFIG_MQ_IOSCHED_ONLY_SQ)
+       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 609c80506cfc77b81bb1675af96b08aaa196267d..391ecc00f52056f22a505c79b875192d0f81e9fb 100644 (file)
--- a/block/blk-mq-sched.h
+++ b/block/blk-mq-sched.h
@@ -25,6 +25,7 @@ struct request *
 blk_mq_sched_request_from_shadow(struct blk_mq_hw_ctx *hctx,
                                 struct request *(*get_sched_rq)(struct blk_mq_hw_ctx *));
 
+int blk_mq_sched_init(struct request_queue *q);
 
 struct blk_mq_alloc_data {
        /* input parameter */

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 019de6f0fd06d5a9f386d930c07b492ddbad9a7b..9eeffd76f72974e1471e39ddf4d85429ff621d6e 100644 (file)
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2141,6 +2141,9 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
        INIT_LIST_HEAD(&q->requeue_list);
        spin_lock_init(&q->requeue_lock);
 
+       if (!(set->flags & BLK_MQ_F_NO_SCHED))
+               blk_mq_sched_init(q);
+
        if (q->nr_hw_queues > 1)
                blk_queue_make_request(q, blk_mq_make_request);
        else

diff --git a/block/elevator.c b/block/elevator.c
index f1191b3b0ff339e32af3d95198853a0bdcfc962a..368976d05f0a19d88871cd752c4614d5b35aa952 100644 (file)
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -219,7 +219,10 @@ int elevator_init(struct request_queue *q, char *name)
        }
 
        if (!e) {
-               e = elevator_get(CONFIG_DEFAULT_IOSCHED, false);
+               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 82b9b3f1f21d57e269f315b16dd6c361f22d6b4b..7777ec58252ffda7743bf50f3f7a376376af3986 100644 (file)
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1186,6 +1186,7 @@ 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 c86b314dde97c1e45c44564046d9c6e5875f9adc..7c470bf4d7bf37d4f5af478fe74f45d9d7332841 100644 (file)
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -152,6 +152,7 @@ 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,