From cc56694f132a8f5fa9334e3afe990de8c3378866 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Mon, 17 Dec 2018 09:46:00 +0800 Subject: [PATCH] blk-mq-debugfs: support rq_qos blk-mq-debugfs has been proved as very helpful for debug some tough issues, such as IO hang. We have seen blk-wbt related IO hang several times, even inside Red Hat BZ, there is such report not sovled yet, so this patch adds support debugfs on rq_qos. Cc: Bart Van Assche Cc: Omar Sandoval Cc: Christoph Hellwig Cc: Josef Bacik Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq-debugfs.c | 54 ++++++++++++++++++++++++++++++++++++++++++ block/blk-mq-debugfs.h | 17 +++++++++++++ block/blk-rq-qos.c | 2 ++ block/blk-rq-qos.h | 24 +++++++++++++++++++ include/linux/blkdev.h | 1 + 5 files changed, 98 insertions(+) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index a32bb79d6c95..2793e91bc7a4 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -23,6 +23,7 @@ #include "blk-mq.h" #include "blk-mq-debugfs.h" #include "blk-mq-tag.h" +#include "blk-rq-qos.h" static void print_stat(struct seq_file *m, struct blk_rq_stat *stat) { @@ -856,6 +857,15 @@ int blk_mq_debugfs_register(struct request_queue *q) goto err; } + if (q->rq_qos) { + struct rq_qos *rqos = q->rq_qos; + + while (rqos) { + blk_mq_debugfs_register_rqos(rqos); + rqos = rqos->next; + } + } + return 0; err: @@ -978,6 +988,50 @@ void blk_mq_debugfs_unregister_sched(struct request_queue *q) q->sched_debugfs_dir = NULL; } +void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos) +{ + debugfs_remove_recursive(rqos->debugfs_dir); + rqos->debugfs_dir = NULL; +} + +int blk_mq_debugfs_register_rqos(struct rq_qos *rqos) +{ + struct request_queue *q = rqos->q; + const char *dir_name = rq_qos_id_to_name(rqos->id); + + if (!q->debugfs_dir) + return -ENOENT; + + if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs) + return 0; + + if (!q->rqos_debugfs_dir) { + q->rqos_debugfs_dir = debugfs_create_dir("rqos", + q->debugfs_dir); + if (!q->rqos_debugfs_dir) + return -ENOMEM; + } + + rqos->debugfs_dir = debugfs_create_dir(dir_name, + rqos->q->rqos_debugfs_dir); + if (!rqos->debugfs_dir) + return -ENOMEM; + + if (!debugfs_create_files(rqos->debugfs_dir, rqos, + rqos->ops->debugfs_attrs)) + goto err; + return 0; + err: + blk_mq_debugfs_unregister_rqos(rqos); + return -ENOMEM; +} + +void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q) +{ + debugfs_remove_recursive(q->rqos_debugfs_dir); + q->rqos_debugfs_dir = NULL; +} + int blk_mq_debugfs_register_sched_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx) { diff --git a/block/blk-mq-debugfs.h b/block/blk-mq-debugfs.h index a9160be12be0..8c9012a578c1 100644 --- a/block/blk-mq-debugfs.h +++ b/block/blk-mq-debugfs.h @@ -31,6 +31,10 @@ void blk_mq_debugfs_unregister_sched(struct request_queue *q); int blk_mq_debugfs_register_sched_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx); void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx); + +int blk_mq_debugfs_register_rqos(struct rq_qos *rqos); +void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos); +void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q); #else static inline int blk_mq_debugfs_register(struct request_queue *q) { @@ -78,6 +82,19 @@ static inline int blk_mq_debugfs_register_sched_hctx(struct request_queue *q, static inline void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx) { } + +static inline int blk_mq_debugfs_register_rqos(struct rq_qos *rqos) +{ + return 0; +} + +static inline void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos) +{ +} + +static inline void blk_mq_debugfs_unregister_queue_rqos(struct request_queue *q) +{ +} #endif #ifdef CONFIG_BLK_DEBUG_FS_ZONED diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c index e932ef9d2718..d169d7188fa6 100644 --- a/block/blk-rq-qos.c +++ b/block/blk-rq-qos.c @@ -264,6 +264,8 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, void rq_qos_exit(struct request_queue *q) { + blk_mq_debugfs_unregister_queue_rqos(q); + while (q->rq_qos) { struct rq_qos *rqos = q->rq_qos; q->rq_qos = rqos->next; diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h index 8678875de420..3c85f26d3846 100644 --- a/block/blk-rq-qos.h +++ b/block/blk-rq-qos.h @@ -7,6 +7,10 @@ #include #include +#include "blk-mq-debugfs.h" + +struct blk_mq_debugfs_attr; + enum rq_qos_id { RQ_QOS_WBT, RQ_QOS_CGROUP, @@ -22,6 +26,9 @@ struct rq_qos { struct request_queue *q; enum rq_qos_id id; struct rq_qos *next; +#ifdef CONFIG_BLK_DEBUG_FS + struct dentry *debugfs_dir; +#endif }; struct rq_qos_ops { @@ -33,6 +40,7 @@ struct rq_qos_ops { void (*done_bio)(struct rq_qos *, struct bio *); void (*cleanup)(struct rq_qos *, struct bio *); void (*exit)(struct rq_qos *); + const struct blk_mq_debugfs_attr *debugfs_attrs; }; struct rq_depth { @@ -66,6 +74,17 @@ static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q) return rq_qos_id(q, RQ_QOS_CGROUP); } +static inline const char *rq_qos_id_to_name(enum rq_qos_id id) +{ + switch (id) { + case RQ_QOS_WBT: + return "wbt"; + case RQ_QOS_CGROUP: + return "cgroup"; + } + return "unknown"; +} + static inline void rq_wait_init(struct rq_wait *rq_wait) { atomic_set(&rq_wait->inflight, 0); @@ -76,6 +95,9 @@ static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos) { rqos->next = q->rq_qos; q->rq_qos = rqos; + + if (rqos->ops->debugfs_attrs) + blk_mq_debugfs_register_rqos(rqos); } static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos) @@ -91,6 +113,8 @@ static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos) } prev = cur; } + + blk_mq_debugfs_unregister_rqos(rqos); } typedef bool (acquire_inflight_cb_t)(struct rq_wait *rqw, void *private_data); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 81f1b105946b..45552e6eae1e 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -560,6 +560,7 @@ struct request_queue { #ifdef CONFIG_BLK_DEBUG_FS struct dentry *debugfs_dir; struct dentry *sched_debugfs_dir; + struct dentry *rqos_debugfs_dir; #endif bool mq_sysfs_init_done;