From d34849913819a5e0cbfbe724dbe79df89278c524 Mon Sep 17 00:00:00 2001 From: Jens Axboe 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 Reviewed-by: Bart Van Assche Reviewed-by: Omar Sandoval --- 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 490ef2850fae..0715ce93daef 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 26759798a0b3..d05061f27bb1 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 35c49e2e008a..6b465bc7014c 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 45e1707a9f86..fa1f8619bfe7 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 0e1ccddab8a2..bcba2dd5cb5c 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 19beeb7b2ac2..e1b4e603b1cf 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 63569eb46d15..8e4df3d6c8cd 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, -- 2.20.1