From d4d957b53d91eebc8c681c480edfdc697e55231e Mon Sep 17 00:00:00 2001 From: Sagi Grimberg Date: Tue, 29 Nov 2022 15:43:19 +0100 Subject: [PATCH] nvme-multipath: support io stats on the mpath device Our mpath stack device is just a shim that selects a bottom namespace and submits the bio to it without any fancy splitting. This also means that we don't clone the bio or have any context to the bio beyond submission. However it really sucks that we don't see the mpath device io stats. Given that the mpath device can't do that without adding some context to it, we let the bottom device do it on its behalf (somewhat similar to the approach taken in nvme_trace_bio_complete). When the IO starts, we account the request for multipath IO stats using REQ_NVME_MPATH_IO_STATS nvme_request flag to avoid queue io stats disable in the middle of the request. Signed-off-by: Sagi Grimberg Signed-off-by: Christoph Hellwig Reviewed-by: Keith Busch --- drivers/nvme/host/core.c | 2 ++ drivers/nvme/host/multipath.c | 26 ++++++++++++++++++++++++++ drivers/nvme/host/nvme.h | 14 ++++++++++++++ 3 files changed, 42 insertions(+) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index fd2e26c..7961e14 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -384,6 +384,8 @@ static inline void nvme_end_req(struct request *req) nvme_log_error(req); nvme_end_req_zoned(req); nvme_trace_bio_complete(req); + if (req->cmd_flags & REQ_NVME_MPATH) + nvme_mpath_end_request(req); blk_mq_end_request(req, status); } diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 0ea7e44..898921e 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -114,6 +114,31 @@ void nvme_failover_req(struct request *req) kblockd_schedule_work(&ns->head->requeue_work); } +void nvme_mpath_start_request(struct request *rq) +{ + struct nvme_ns *ns = rq->q->queuedata; + struct gendisk *disk = ns->head->disk; + + if (!blk_queue_io_stat(disk->queue) || blk_rq_is_passthrough(rq)) + return; + + nvme_req(rq)->flags |= NVME_MPATH_IO_STATS; + nvme_req(rq)->start_time = bdev_start_io_acct(disk->part0, + blk_rq_bytes(rq) >> SECTOR_SHIFT, + req_op(rq), jiffies); +} +EXPORT_SYMBOL_GPL(nvme_mpath_start_request); + +void nvme_mpath_end_request(struct request *rq) +{ + struct nvme_ns *ns = rq->q->queuedata; + + if (!(nvme_req(rq)->flags & NVME_MPATH_IO_STATS)) + return; + bdev_end_io_acct(ns->head->disk->part0, req_op(rq), + nvme_req(rq)->start_time); +} + void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl) { struct nvme_ns *ns; @@ -503,6 +528,7 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head) blk_queue_flag_set(QUEUE_FLAG_NONROT, head->disk->queue); blk_queue_flag_set(QUEUE_FLAG_NOWAIT, head->disk->queue); + blk_queue_flag_set(QUEUE_FLAG_IO_STAT, head->disk->queue); /* * This assumes all controllers that refer to a namespace either * support poll queues or not. That is not a strict guarantee, diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 8522d6d..e01fa9f 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -162,6 +162,9 @@ struct nvme_request { u8 retries; u8 flags; u16 status; +#ifdef CONFIG_NVME_MULTIPATH + unsigned long start_time; +#endif struct nvme_ctrl *ctrl; }; @@ -173,6 +176,7 @@ struct nvme_request { enum { NVME_REQ_CANCELLED = (1 << 0), NVME_REQ_USERCMD = (1 << 1), + NVME_MPATH_IO_STATS = (1 << 2), }; static inline struct nvme_request *nvme_req(struct request *req) @@ -882,6 +886,8 @@ bool nvme_mpath_clear_current_path(struct nvme_ns *ns); void nvme_mpath_revalidate_paths(struct nvme_ns *ns); void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl); void nvme_mpath_shutdown_disk(struct nvme_ns_head *head); +void nvme_mpath_start_request(struct request *rq); +void nvme_mpath_end_request(struct request *rq); static inline void nvme_trace_bio_complete(struct request *req) { @@ -967,6 +973,12 @@ static inline void nvme_mpath_start_freeze(struct nvme_subsystem *subsys) static inline void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys) { } +static inline void nvme_mpath_start_request(struct request *rq) +{ +} +static inline void nvme_mpath_end_request(struct request *rq) +{ +} #endif /* CONFIG_NVME_MULTIPATH */ int nvme_revalidate_zones(struct nvme_ns *ns); @@ -1014,6 +1026,8 @@ static inline void nvme_hwmon_exit(struct nvme_ctrl *ctrl) static inline void nvme_start_request(struct request *rq) { + if (rq->cmd_flags & REQ_NVME_MPATH) + nvme_mpath_start_request(rq); blk_mq_start_request(rq); } -- 2.7.4