From faad87df4b907605815c711dca613b3e7755e0d9 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 28 Jan 2016 16:52:56 -0500 Subject: [PATCH] dm: add 'dm_mq_nr_hw_queues' and 'dm_mq_queue_depth' module params Allow user to change these values via module params or sysfs. 'dm_mq_nr_hw_queues' defaults to 1 (max 32). 'dm_mq_queue_depth' defaults to 2048 (up from 64, which proved far too small under moderate sized workloads -- the dm-multipath device would continuously block waiting for tags (requests) to become available). The maximum is BLK_MQ_MAX_DEPTH (currently 10240). Keep in mind the total number of pre-allocated requests per request-based dm-mq device is 'dm_mq_nr_hw_queues' * 'dm_mq_queue_depth' (currently 2048). Signed-off-by: Mike Snitzer --- drivers/md/dm.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 621450282d08..d17be1efb4d8 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -233,6 +233,12 @@ static bool use_blk_mq = true; static bool use_blk_mq = false; #endif +#define DM_MQ_NR_HW_QUEUES 1 +#define DM_MQ_QUEUE_DEPTH 2048 + +static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES; +static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH; + bool dm_use_blk_mq(struct mapped_device *md) { return md->use_blk_mq; @@ -303,6 +309,17 @@ unsigned dm_get_reserved_rq_based_ios(void) } EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios); +static unsigned dm_get_blk_mq_nr_hw_queues(void) +{ + return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32); +} + +static unsigned dm_get_blk_mq_queue_depth(void) +{ + return __dm_get_module_param(&dm_mq_queue_depth, + DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH); +} + static int __init local_init(void) { int r = -ENOMEM; @@ -2695,10 +2712,10 @@ static int dm_init_request_based_blk_mq_queue(struct mapped_device *md) memset(&md->tag_set, 0, sizeof(md->tag_set)); md->tag_set.ops = &dm_mq_ops; - md->tag_set.queue_depth = BLKDEV_MAX_RQ; + md->tag_set.queue_depth = dm_get_blk_mq_queue_depth(); md->tag_set.numa_node = NUMA_NO_NODE; md->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; - md->tag_set.nr_hw_queues = 1; + md->tag_set.nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); if (md_type == DM_TYPE_REQUEST_BASED) { /* make the memory for non-blk-mq clone part of the pdu */ md->tag_set.cmd_size = sizeof(struct dm_rq_target_io) + sizeof(struct request); @@ -3669,6 +3686,12 @@ MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools" module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices"); +module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices"); + +module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices"); + MODULE_DESCRIPTION(DM_NAME " driver"); MODULE_AUTHOR("Joe Thornber "); MODULE_LICENSE("GPL"); -- 2.20.1