[linux.git] / block / blk-mq-tag.c

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/percpu_ida.h>

#include <linux/blk-mq.h>
#include "blk.h"
#include "blk-mq.h"
#include "blk-mq-tag.h"

/*
 * Per tagged queue (tag address space) map
 */
struct blk_mq_tags {
	unsigned int nr_tags;
	unsigned int nr_reserved_tags;
	unsigned int nr_batch_move;
	unsigned int nr_max_cache;

	struct percpu_ida free_tags;
	struct percpu_ida reserved_tags;
};

void blk_mq_wait_for_tags(struct blk_mq_tags *tags)
{
	int tag = blk_mq_get_tag(tags, __GFP_WAIT, false);
	blk_mq_put_tag(tags, tag);
}

bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
{
	return !tags ||
		percpu_ida_free_tags(&tags->free_tags, nr_cpu_ids) != 0;
}

static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp)
{
	int tag;

	tag = percpu_ida_alloc(&tags->free_tags, (gfp & __GFP_WAIT) ?
			       TASK_UNINTERRUPTIBLE : TASK_RUNNING);
	if (tag < 0)
		return BLK_MQ_TAG_FAIL;
	return tag + tags->nr_reserved_tags;
}

static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags,
					      gfp_t gfp)
{
	int tag;

	if (unlikely(!tags->nr_reserved_tags)) {
		WARN_ON_ONCE(1);
		return BLK_MQ_TAG_FAIL;
	}

	tag = percpu_ida_alloc(&tags->reserved_tags, (gfp & __GFP_WAIT) ?
			       TASK_UNINTERRUPTIBLE : TASK_RUNNING);
	if (tag < 0)
		return BLK_MQ_TAG_FAIL;
	return tag;
}

unsigned int blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp, bool reserved)
{
	if (!reserved)
		return __blk_mq_get_tag(tags, gfp);

	return __blk_mq_get_reserved_tag(tags, gfp);
}

static void __blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag)
{
	BUG_ON(tag >= tags->nr_tags);

	percpu_ida_free(&tags->free_tags, tag - tags->nr_reserved_tags);
}

static void __blk_mq_put_reserved_tag(struct blk_mq_tags *tags,
				      unsigned int tag)
{
	BUG_ON(tag >= tags->nr_reserved_tags);

	percpu_ida_free(&tags->reserved_tags, tag);
}

void blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag)
{
	if (tag >= tags->nr_reserved_tags)
		__blk_mq_put_tag(tags, tag);
	else
		__blk_mq_put_reserved_tag(tags, tag);
}

static int __blk_mq_tag_iter(unsigned id, void *data)
{
	unsigned long *tag_map = data;
	__set_bit(id, tag_map);
	return 0;
}

void blk_mq_tag_busy_iter(struct blk_mq_tags *tags,
			  void (*fn)(void *, unsigned long *), void *data)
{
	unsigned long *tag_map;
	size_t map_size;

	map_size = ALIGN(tags->nr_tags, BITS_PER_LONG) / BITS_PER_LONG;
	tag_map = kzalloc(map_size * sizeof(unsigned long), GFP_ATOMIC);
	if (!tag_map)
		return;

	percpu_ida_for_each_free(&tags->free_tags, __blk_mq_tag_iter, tag_map);
	if (tags->nr_reserved_tags)
		percpu_ida_for_each_free(&tags->reserved_tags, __blk_mq_tag_iter,
			tag_map);

	fn(data, tag_map);
	kfree(tag_map);
}

struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
				     unsigned int reserved_tags, int node)
{
	unsigned int nr_tags, nr_cache;
	struct blk_mq_tags *tags;
	int ret;

	if (total_tags > BLK_MQ_TAG_MAX) {
		pr_err("blk-mq: tag depth too large\n");
		return NULL;
	}

	tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
	if (!tags)
		return NULL;

	nr_tags = total_tags - reserved_tags;
	nr_cache = nr_tags / num_possible_cpus();

	if (nr_cache < BLK_MQ_TAG_CACHE_MIN)
		nr_cache = BLK_MQ_TAG_CACHE_MIN;
	else if (nr_cache > BLK_MQ_TAG_CACHE_MAX)
		nr_cache = BLK_MQ_TAG_CACHE_MAX;

	tags->nr_tags = total_tags;
	tags->nr_reserved_tags = reserved_tags;
	tags->nr_max_cache = nr_cache;
	tags->nr_batch_move = max(1u, nr_cache / 2);

	ret = __percpu_ida_init(&tags->free_tags, tags->nr_tags -
				tags->nr_reserved_tags,
				tags->nr_max_cache,
				tags->nr_batch_move);
	if (ret)
		goto err_free_tags;

	if (reserved_tags) {
		/*
		 * With max_cahe and batch set to 1, the allocator fallbacks to
		 * no cached. It's fine reserved tags allocation is slow.
		 */
		ret = __percpu_ida_init(&tags->reserved_tags, reserved_tags,
				1, 1);
		if (ret)
			goto err_reserved_tags;
	}

	return tags;

err_reserved_tags:
	percpu_ida_destroy(&tags->free_tags);
err_free_tags:
	kfree(tags);
	return NULL;
}

void blk_mq_free_tags(struct blk_mq_tags *tags)
{
	percpu_ida_destroy(&tags->free_tags);
	percpu_ida_destroy(&tags->reserved_tags);
	kfree(tags);
}

ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page)
{
	char *orig_page = page;
	int cpu;

	if (!tags)
		return 0;

	page += sprintf(page, "nr_tags=%u, reserved_tags=%u, batch_move=%u,"
			" max_cache=%u\n", tags->nr_tags, tags->nr_reserved_tags,
			tags->nr_batch_move, tags->nr_max_cache);

	page += sprintf(page, "nr_free=%u, nr_reserved=%u\n",
			percpu_ida_free_tags(&tags->free_tags, nr_cpu_ids),
			percpu_ida_free_tags(&tags->reserved_tags, nr_cpu_ids));

	for_each_possible_cpu(cpu) {
		page += sprintf(page, "  cpu%02u: nr_free=%u\n", cpu,
				percpu_ida_free_tags(&tags->free_tags, cpu));
	}

	return page - orig_page;
}
Commit	Line	Data
320ae51f JA	1	#include <linux/kernel.h>
	2	#include <linux/module.h>
	3	#include <linux/percpu_ida.h>
	4
	5	#include <linux/blk-mq.h>
	6	#include "blk.h"
	7	#include "blk-mq.h"
	8	#include "blk-mq-tag.h"
	9
	10	/*
	11	* Per tagged queue (tag address space) map
	12	*/
	13	struct blk_mq_tags {
	14	unsigned int nr_tags;
	15	unsigned int nr_reserved_tags;
	16	unsigned int nr_batch_move;
	17	unsigned int nr_max_cache;
	18
	19	struct percpu_ida free_tags;
	20	struct percpu_ida reserved_tags;
	21	};
	22
	23	void blk_mq_wait_for_tags(struct blk_mq_tags *tags)
	24	{
	25	int tag = blk_mq_get_tag(tags, __GFP_WAIT, false);
	26	blk_mq_put_tag(tags, tag);
	27	}
	28
	29	bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
	30	{
	31	return !tags \|\|
	32	percpu_ida_free_tags(&tags->free_tags, nr_cpu_ids) != 0;
	33	}
	34
	35	static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp)
	36	{
	37	int tag;
	38
6f6b5d1e KO	39	tag = percpu_ida_alloc(&tags->free_tags, (gfp & __GFP_WAIT) ?
6f6b5d1e KO	40	TASK_UNINTERRUPTIBLE : TASK_RUNNING);
320ae51f JA	41	if (tag < 0)
	42	return BLK_MQ_TAG_FAIL;
	43	return tag + tags->nr_reserved_tags;
	44	}
	45
	46	static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags,
	47	gfp_t gfp)
	48	{
	49	int tag;
	50
	51	if (unlikely(!tags->nr_reserved_tags)) {
	52	WARN_ON_ONCE(1);
	53	return BLK_MQ_TAG_FAIL;
	54	}
	55
6f6b5d1e KO	56	tag = percpu_ida_alloc(&tags->reserved_tags, (gfp & __GFP_WAIT) ?
6f6b5d1e KO	57	TASK_UNINTERRUPTIBLE : TASK_RUNNING);
320ae51f JA	58	if (tag < 0)
	59	return BLK_MQ_TAG_FAIL;
	60	return tag;
	61	}
	62
	63	unsigned int blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp, bool reserved)
	64	{
	65	if (!reserved)
	66	return __blk_mq_get_tag(tags, gfp);
	67
	68	return __blk_mq_get_reserved_tag(tags, gfp);
	69	}
	70
	71	static void __blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag)
	72	{
	73	BUG_ON(tag >= tags->nr_tags);
	74
	75	percpu_ida_free(&tags->free_tags, tag - tags->nr_reserved_tags);
	76	}
	77
	78	static void __blk_mq_put_reserved_tag(struct blk_mq_tags *tags,
	79	unsigned int tag)
	80	{
	81	BUG_ON(tag >= tags->nr_reserved_tags);
	82
	83	percpu_ida_free(&tags->reserved_tags, tag);
	84	}
	85
	86	void blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag)
	87	{
	88	if (tag >= tags->nr_reserved_tags)
	89	__blk_mq_put_tag(tags, tag);
	90	else
	91	__blk_mq_put_reserved_tag(tags, tag);
	92	}
	93
	94	static int __blk_mq_tag_iter(unsigned id, void *data)
	95	{
	96	unsigned long *tag_map = data;
	97	__set_bit(id, tag_map);
	98	return 0;
	99	}
	100
	101	void blk_mq_tag_busy_iter(struct blk_mq_tags *tags,
	102	void (fn)(void , unsigned long ), void data)
	103	{
	104	unsigned long *tag_map;
	105	size_t map_size;
	106
	107	map_size = ALIGN(tags->nr_tags, BITS_PER_LONG) / BITS_PER_LONG;
	108	tag_map = kzalloc(map_size * sizeof(unsigned long), GFP_ATOMIC);
	109	if (!tag_map)
	110	return;
	111
	112	percpu_ida_for_each_free(&tags->free_tags, __blk_mq_tag_iter, tag_map);
	113	if (tags->nr_reserved_tags)
	114	percpu_ida_for_each_free(&tags->reserved_tags, __blk_mq_tag_iter,
	115	tag_map);
	116
	117	fn(data, tag_map);
	118	kfree(tag_map);
	119	}
	120
	121	struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
122	unsigned int reserved_tags, int node)
123	{
124	unsigned int nr_tags, nr_cache;
125	struct blk_mq_tags *tags;
126	int ret;
127
128	if (total_tags > BLK_MQ_TAG_MAX) {
129	pr_err("blk-mq: tag depth too large\n");
130	return NULL;
131	}
132
133	tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
134	if (!tags)
135	return NULL;
136
137	nr_tags = total_tags - reserved_tags;
138	nr_cache = nr_tags / num_possible_cpus();
139
140	if (nr_cache < BLK_MQ_TAG_CACHE_MIN)
141	nr_cache = BLK_MQ_TAG_CACHE_MIN;
142	else if (nr_cache > BLK_MQ_TAG_CACHE_MAX)
143	nr_cache = BLK_MQ_TAG_CACHE_MAX;
144
145	tags->nr_tags = total_tags;
146	tags->nr_reserved_tags = reserved_tags;
147	tags->nr_max_cache = nr_cache;
148	tags->nr_batch_move = max(1u, nr_cache / 2);
149
150	ret = __percpu_ida_init(&tags->free_tags, tags->nr_tags -
151	tags->nr_reserved_tags,
152	tags->nr_max_cache,
153	tags->nr_batch_move);
154	if (ret)
155	goto err_free_tags;
156
157	if (reserved_tags) {
158	/*
159	* With max_cahe and batch set to 1, the allocator fallbacks to
160	* no cached. It's fine reserved tags allocation is slow.
161	*/
162	ret = __percpu_ida_init(&tags->reserved_tags, reserved_tags,
163	1, 1);
164	if (ret)
165	goto err_reserved_tags;
166	}
167
168	return tags;
169
170	err_reserved_tags:
171	percpu_ida_destroy(&tags->free_tags);
172	err_free_tags:
173	kfree(tags);
174	return NULL;
175	}
176
177	void blk_mq_free_tags(struct blk_mq_tags *tags)
178	{
179	percpu_ida_destroy(&tags->free_tags);
180	percpu_ida_destroy(&tags->reserved_tags);
181	kfree(tags);
182	}
183
184	ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags tags, char page)
185	{
186	char *orig_page = page;
187	int cpu;
188
189	if (!tags)
190	return 0;
191
192	page += sprintf(page, "nr_tags=%u, reserved_tags=%u, batch_move=%u,"
193	" max_cache=%u\n", tags->nr_tags, tags->nr_reserved_tags,
194	tags->nr_batch_move, tags->nr_max_cache);
195
196	page += sprintf(page, "nr_free=%u, nr_reserved=%u\n",
197	percpu_ida_free_tags(&tags->free_tags, nr_cpu_ids),
198	percpu_ida_free_tags(&tags->reserved_tags, nr_cpu_ids));
199
200	for_each_possible_cpu(cpu) {
201	page += sprintf(page, " cpu%02u: nr_free=%u\n", cpu,
202	percpu_ida_free_tags(&tags->free_tags, cpu));
203	}
204
205	return page - orig_page;
206	}