Commit d96b37c0 authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
Browse files

blk-mq: move tags and sched_tags info from sysfs to debugfs 



These are very tied to the blk-mq tag implementation, so exposing them
to sysfs isn't a great idea. Move the debugging information to debugfs
and add basic entries for the number of tags and the number of reserved
tags to sysfs.

Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 0bfa5288

block/blk-mq-debugfs.c

+70 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ 


#include <linux/blk-mq.h>

#include "blk-mq.h"

#include "blk-mq-tag.h"



struct blk_mq_debugfs_attr {

	const char *name;
@@ -154,6 +155,73 @@ static const struct file_operations hctx_ctx_map_fops = { 
	.release	= single_release,

};



static void blk_mq_debugfs_tags_show(struct seq_file *m,

				     struct blk_mq_tags *tags)

{

	seq_printf(m, "nr_tags=%u\n", tags->nr_tags);

	seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);

	seq_printf(m, "active_queues=%d\n",

		   atomic_read(&tags->active_queues));



	seq_puts(m, "\nbitmap_tags:\n");

	sbitmap_queue_show(&tags->bitmap_tags, m);



	if (tags->nr_reserved_tags) {

		seq_puts(m, "\nbreserved_tags:\n");

		sbitmap_queue_show(&tags->breserved_tags, m);

	}

}



static int hctx_tags_show(struct seq_file *m, void *v)

{

	struct blk_mq_hw_ctx *hctx = m->private;

	struct request_queue *q = hctx->queue;



	mutex_lock(&q->sysfs_lock);

	if (hctx->tags)

		blk_mq_debugfs_tags_show(m, hctx->tags);

	mutex_unlock(&q->sysfs_lock);



	return 0;

}



static int hctx_tags_open(struct inode *inode, struct file *file)

{

	return single_open(file, hctx_tags_show, inode->i_private);

}



static const struct file_operations hctx_tags_fops = {

	.open		= hctx_tags_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};



static int hctx_sched_tags_show(struct seq_file *m, void *v)

{

	struct blk_mq_hw_ctx *hctx = m->private;

	struct request_queue *q = hctx->queue;



	mutex_lock(&q->sysfs_lock);

	if (hctx->sched_tags)

		blk_mq_debugfs_tags_show(m, hctx->sched_tags);

	mutex_unlock(&q->sysfs_lock);



	return 0;

}



static int hctx_sched_tags_open(struct inode *inode, struct file *file)

{

	return single_open(file, hctx_sched_tags_show, inode->i_private);

}



static const struct file_operations hctx_sched_tags_fops = {

	.open		= hctx_sched_tags_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};



static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)

{

	struct blk_mq_ctx *ctx = m->private;
@@ -200,6 +268,8 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = { 
	{"flags", 0400, &hctx_flags_fops},

	{"dispatch", 0400, &hctx_dispatch_fops},

	{"ctx_map", 0400, &hctx_ctx_map_fops},

	{"tags", 0400, &hctx_tags_fops},

	{"sched_tags", 0400, &hctx_sched_tags_fops},

};



static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {

block/blk-mq-sysfs.c

+16 −17
Original line number Diff line number Diff line
@@ -184,17 +184,16 @@ static ssize_t blk_mq_hw_sysfs_dispatched_show(struct blk_mq_hw_ctx *hctx, 
	return page - start_page;

}



static ssize_t blk_mq_hw_sysfs_sched_tags_show(struct blk_mq_hw_ctx *hctx, char *page)

static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,

					    char *page)

{

	if (hctx->sched_tags)

		return blk_mq_tag_sysfs_show(hctx->sched_tags, page);



	return 0;

	return sprintf(page, "%u\n", hctx->tags->nr_tags);

}



static ssize_t blk_mq_hw_sysfs_tags_show(struct blk_mq_hw_ctx *hctx, char *page)

static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,

						     char *page)

{

	return blk_mq_tag_sysfs_show(hctx->tags, page);

	return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);

}



static ssize_t blk_mq_hw_sysfs_active_show(struct blk_mq_hw_ctx *hctx, char *page)
@@ -293,18 +292,18 @@ static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_dispatched = { 
	.attr = {.name = "dispatched", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_dispatched_show,

};

static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {

	.attr = {.name = "nr_tags", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_nr_tags_show,

};

static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {

	.attr = {.name = "nr_reserved_tags", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_nr_reserved_tags_show,

};

static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_active = {

	.attr = {.name = "active", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_active_show,

};

static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_sched_tags = {

	.attr = {.name = "sched_tags", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_sched_tags_show,

};

static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_tags = {

	.attr = {.name = "tags", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_tags_show,

};

static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {

	.attr = {.name = "cpu_list", .mode = S_IRUGO },

	.show = blk_mq_hw_sysfs_cpus_show,
@@ -324,8 +323,8 @@ static struct attribute *default_hw_ctx_attrs[] = { 
	&blk_mq_hw_sysfs_queued.attr,

	&blk_mq_hw_sysfs_run.attr,

	&blk_mq_hw_sysfs_dispatched.attr,

	&blk_mq_hw_sysfs_tags.attr,

	&blk_mq_hw_sysfs_sched_tags.attr,

	&blk_mq_hw_sysfs_nr_tags.attr,

	&blk_mq_hw_sysfs_nr_reserved_tags.attr,

	&blk_mq_hw_sysfs_cpus.attr,

	&blk_mq_hw_sysfs_active.attr,

	&blk_mq_hw_sysfs_poll.attr,

block/blk-mq-tag.c

+0 −27
Original line number Diff line number Diff line
@@ -329,11 +329,6 @@ void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn, 


}



static unsigned int bt_unused_tags(const struct sbitmap_queue *bt)

{

	return bt->sb.depth - sbitmap_weight(&bt->sb);

}



static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,

		    bool round_robin, int node)

{
@@ -469,25 +464,3 @@ u32 blk_mq_unique_tag(struct request *rq) 
		(rq->tag & BLK_MQ_UNIQUE_TAG_MASK);

}

EXPORT_SYMBOL(blk_mq_unique_tag);
 


ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page)

{

	char *orig_page = page;

	unsigned int free, res;



	if (!tags)

		return 0;



	page += sprintf(page, "nr_tags=%u, reserved_tags=%u, "

			"bits_per_word=%u\n",

			tags->nr_tags, tags->nr_reserved_tags,

			1U << tags->bitmap_tags.sb.shift);



	free = bt_unused_tags(&tags->bitmap_tags);

	res = bt_unused_tags(&tags->breserved_tags);



	page += sprintf(page, "nr_free=%u, nr_reserved=%u\n", free, res);

	page += sprintf(page, "active_queues=%u\n", atomic_read(&tags->active_queues));



	return page - orig_page;

}

block/blk-mq-tag.h

+0 −1
Original line number Diff line number Diff line
@@ -28,7 +28,6 @@ extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data); 
extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,

			   struct blk_mq_ctx *ctx, unsigned int tag);

extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);

extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);

extern int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,

					struct blk_mq_tags **tags,

					unsigned int depth, bool can_grow);

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