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blk-mq: create debugfs directory tree

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In preparation for putting blk-mq debugging information in debugfs,
create a directory tree mirroring the one in sysfs:

    # tree -d /sys/kernel/debug/block
    /sys/kernel/debug/block
    |-- nvme0n1
    |   `-- mq
    |       |-- 0
    |       |   `-- cpu0
    |       |-- 1
    |       |   `-- cpu1
    |       |-- 2
    |       |   `-- cpu2
    |       `-- 3
    |           `-- cpu3
    `-- vda
        `-- mq
            `-- 0
                |-- cpu0
                |-- cpu1
                |-- cpu2
                `-- cpu3

Also add the scaffolding for the actual files that will go in here,
either under the hardware queue or software queue directories.

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Omar Sandoval 2017-01-25 08:06:40 -08:00 committed by Jens Axboe
parent b48fda0976
commit 07e4fead45
6 changed files with 201 additions and 0 deletions
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1
block/Makefile
View File

@ -26,3 +26,4 @@ obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o
obj-$(CONFIG_BLK_MQ_PCI) += blk-mq-pci.o
obj-$(CONFIG_BLK_DEV_ZONED) += blk-zoned.o
obj-$(CONFIG_BLK_WBT) += blk-wbt.o
obj-$(CONFIG_DEBUG_FS) += blk-mq-debugfs.o

152
block/blk-mq-debugfs.c Normal file
View File

@ -0,0 +1,152 @@
/*
* Copyright (C) 2017 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/debugfs.h>
#include <linux/blk-mq.h>
#include "blk-mq.h"
struct blk_mq_debugfs_attr {
const char *name;
umode_t mode;
const struct file_operations *fops;
};
static struct dentry *block_debugfs_root;
static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
};
static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
};
int blk_mq_debugfs_register(struct request_queue *q, const char *name)
{
if (!block_debugfs_root)
return -ENOENT;
q->debugfs_dir = debugfs_create_dir(name, block_debugfs_root);
if (!q->debugfs_dir)
goto err;
if (blk_mq_debugfs_register_hctxs(q))
goto err;
return 0;
err:
blk_mq_debugfs_unregister(q);
return -ENOMEM;
}
void blk_mq_debugfs_unregister(struct request_queue *q)
{
debugfs_remove_recursive(q->debugfs_dir);
q->mq_debugfs_dir = NULL;
q->debugfs_dir = NULL;
}
static int blk_mq_debugfs_register_ctx(struct request_queue *q,
struct blk_mq_ctx *ctx,
struct dentry *hctx_dir)
{
struct dentry *ctx_dir;
char name[20];
int i;
snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
ctx_dir = debugfs_create_dir(name, hctx_dir);
if (!ctx_dir)
return -ENOMEM;
for (i = 0; i < ARRAY_SIZE(blk_mq_debugfs_ctx_attrs); i++) {
const struct blk_mq_debugfs_attr *attr;
attr = &blk_mq_debugfs_ctx_attrs[i];
if (!debugfs_create_file(attr->name, attr->mode, ctx_dir, ctx,
attr->fops))
return -ENOMEM;
}
return 0;
}
static int blk_mq_debugfs_register_hctx(struct request_queue *q,
struct blk_mq_hw_ctx *hctx)
{
struct blk_mq_ctx *ctx;
struct dentry *hctx_dir;
char name[20];
int i;
snprintf(name, sizeof(name), "%u", hctx->queue_num);
hctx_dir = debugfs_create_dir(name, q->mq_debugfs_dir);
if (!hctx_dir)
return -ENOMEM;
for (i = 0; i < ARRAY_SIZE(blk_mq_debugfs_hctx_attrs); i++) {
const struct blk_mq_debugfs_attr *attr;
attr = &blk_mq_debugfs_hctx_attrs[i];
if (!debugfs_create_file(attr->name, attr->mode, hctx_dir, hctx,
attr->fops))
return -ENOMEM;
}
hctx_for_each_ctx(hctx, ctx, i) {
if (blk_mq_debugfs_register_ctx(q, ctx, hctx_dir))
return -ENOMEM;
}
return 0;
}
int blk_mq_debugfs_register_hctxs(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
int i;
if (!q->debugfs_dir)
return -ENOENT;
q->mq_debugfs_dir = debugfs_create_dir("mq", q->debugfs_dir);
if (!q->mq_debugfs_dir)
goto err;
queue_for_each_hw_ctx(q, hctx, i) {
if (blk_mq_debugfs_register_hctx(q, hctx))
goto err;
}
return 0;
err:
blk_mq_debugfs_unregister_hctxs(q);
return -ENOMEM;
}
void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
{
debugfs_remove_recursive(q->mq_debugfs_dir);
q->mq_debugfs_dir = NULL;
}
void blk_mq_debugfs_init(void)
{
block_debugfs_root = debugfs_create_dir("block", NULL);
}

8
block/blk-mq-sysfs.c
View File

@ -468,6 +468,8 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
kobject_put(&hctx->kobj);
}
blk_mq_debugfs_unregister(q);
kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
kobject_del(&q->mq_kobj);
kobject_put(&q->mq_kobj);
@ -517,6 +519,8 @@ int blk_mq_register_dev(struct device *dev, struct request_queue *q)
kobject_uevent(&q->mq_kobj, KOBJ_ADD);
blk_mq_debugfs_register(q, kobject_name(&dev->kobj));
queue_for_each_hw_ctx(q, hctx, i) {
ret = blk_mq_register_hctx(hctx);
if (ret)
@ -542,6 +546,8 @@ void blk_mq_sysfs_unregister(struct request_queue *q)
if (!q->mq_sysfs_init_done)
return;
blk_mq_debugfs_unregister_hctxs(q);
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_unregister_hctx(hctx);
}
@ -554,6 +560,8 @@ int blk_mq_sysfs_register(struct request_queue *q)
if (!q->mq_sysfs_init_done)
return ret;
blk_mq_debugfs_register_hctxs(q);
queue_for_each_hw_ctx(q, hctx, i) {
ret = blk_mq_register_hctx(hctx);
if (ret)

2
block/blk-mq.c
View File

@ -2799,6 +2799,8 @@ void blk_mq_enable_hotplug(void)
static int __init blk_mq_init(void)
{
blk_mq_debugfs_init();
cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
blk_mq_hctx_notify_dead);

33
block/blk-mq.h
View File

@ -78,6 +78,39 @@ extern int blk_mq_sysfs_register(struct request_queue *q);
extern void blk_mq_sysfs_unregister(struct request_queue *q);
extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
/*
* debugfs helpers
*/
#ifdef CONFIG_DEBUG_FS
void blk_mq_debugfs_init(void);
int blk_mq_debugfs_register(struct request_queue *q, const char *name);
void blk_mq_debugfs_unregister(struct request_queue *q);
int blk_mq_debugfs_register_hctxs(struct request_queue *q);
void blk_mq_debugfs_unregister_hctxs(struct request_queue *q);
#else
static inline void blk_mq_debugfs_init(void)
{
}
int blk_mq_debugfs_register(struct request_queue *q, const char *name);
{
return 0;
}
void blk_mq_debugfs_unregister(struct request_queue *q)
{
}
int blk_mq_debugfs_register_hctxs(struct request_queue *q)
{
return 0;
}
void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
{
}
#endif
extern void blk_mq_rq_timed_out(struct request *req, bool reserved);
void blk_mq_release(struct request_queue *q);

5
include/linux/blkdev.h
View File

@ -571,6 +571,11 @@ struct request_queue {
struct list_head tag_set_list;
struct bio_set *bio_split;
#ifdef CONFIG_DEBUG_FS
struct dentry *debugfs_dir;
struct dentry *mq_debugfs_dir;
#endif
bool mq_sysfs_init_done;
};