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 <bart.vanassche@wdc.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 8678875..3c85f26 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -7,6 +7,10 @@
#include <linux/atomic.h>
#include <linux/wait.h>
+#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);