Commit cc56694f authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe

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: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent f9824952
......@@ -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)
{
......
......@@ -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
......
......@@ -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;
......
......@@ -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);
......
......@@ -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;
......
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