Commit 34d0f179 authored by Gui Jianfeng's avatar Gui Jianfeng Committed by Jens Axboe
Browse files

io-controller: Add a new interface "weight_device" for IO-Controller 



Currently, IO Controller makes use of blkio.weight to assign weight for
all devices. Here a new user interface "blkio.weight_device" is introduced to
assign different weights for different devices. blkio.weight becomes the
default value for devices which are not configured by "blkio.weight_device"

You can use the following format to assigned specific weight for a given
device:
#echo "major:minor weight" > blkio.weight_device

major:minor represents device number.

And you can remove weight for a given device as following:
#echo "major:minor 0" > blkio.weight_device

V1->V2 changes:
- use user interface "weight_device" instead of "policy" suggested by Vivek
- rename some struct suggested by Vivek
- rebase to 2.6-block "for-linus" branch
- remove an useless list_empty check pointed out by Li Zefan
- some trivial typo fix

V2->V3 changes:
- Move policy_*_node() functions up to get rid of forward declarations
- rename related functions by adding prefix "blkio_"

Signed-off-by: default avatarGui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 812df48d

block/blk-cgroup.c

+236 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/err.h>

#include <linux/blkdev.h>

#include "blk-cgroup.h"

#include <linux/genhd.h>



#define MAX_KEY_LEN 100
@@ -51,6 +52,32 @@ struct cgroup_subsys blkio_subsys = { 
};

EXPORT_SYMBOL_GPL(blkio_subsys);



static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,

					    struct blkio_policy_node *pn)

{

	list_add(&pn->node, &blkcg->policy_list);

}



/* Must be called with blkcg->lock held */

static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)

{

	list_del(&pn->node);

}



/* Must be called with blkcg->lock held */

static struct blkio_policy_node *

blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev)

{

	struct blkio_policy_node *pn;



	list_for_each_entry(pn, &blkcg->policy_list, node) {

		if (pn->dev == dev)

			return pn;

	}



	return NULL;

}



struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)

{

	return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
@@ -398,6 +425,7 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) 
	struct blkio_group *blkg;

	struct hlist_node *n;

	struct blkio_policy_type *blkiop;

	struct blkio_policy_node *pn;



	if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)

		return -EINVAL;
@@ -406,7 +434,13 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val) 
	spin_lock(&blkio_list_lock);

	spin_lock_irq(&blkcg->lock);

	blkcg->weight = (unsigned int)val;



	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {

		pn = blkio_policy_search_node(blkcg, blkg->dev);



		if (pn)

			continue;



		list_for_each_entry(blkiop, &blkio_list, list)

			blkiop->ops.blkio_update_group_weight_fn(blkg,

					blkcg->weight);
@@ -611,7 +645,202 @@ void blkiocg_update_dequeue_stats(struct blkio_group *blkg, 
EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);

#endif



static int blkio_check_dev_num(dev_t dev)

{

	int part = 0;

	struct gendisk *disk;



	disk = get_gendisk(dev, &part);

	if (!disk || part)

		return -ENODEV;



	return 0;

}



static int blkio_policy_parse_and_set(char *buf,

				      struct blkio_policy_node *newpn)

{

	char *s[4], *p, *major_s = NULL, *minor_s = NULL;

	int ret;

	unsigned long major, minor, temp;

	int i = 0;

	dev_t dev;



	memset(s, 0, sizeof(s));



	while ((p = strsep(&buf, " ")) != NULL) {

		if (!*p)

			continue;



		s[i++] = p;



		/* Prevent from inputing too many things */

		if (i == 3)

			break;

	}



	if (i != 2)

		return -EINVAL;



	p = strsep(&s[0], ":");

	if (p != NULL)

		major_s = p;

	else

		return -EINVAL;



	minor_s = s[0];

	if (!minor_s)

		return -EINVAL;



	ret = strict_strtoul(major_s, 10, &major);

	if (ret)

		return -EINVAL;



	ret = strict_strtoul(minor_s, 10, &minor);

	if (ret)

		return -EINVAL;



	dev = MKDEV(major, minor);



	ret = blkio_check_dev_num(dev);

	if (ret)

		return ret;



	newpn->dev = dev;



	if (s[1] == NULL)

		return -EINVAL;



	ret = strict_strtoul(s[1], 10, &temp);

	if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) ||

	    temp > BLKIO_WEIGHT_MAX)

		return -EINVAL;



	newpn->weight =  temp;



	return 0;

}



unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,

			      dev_t dev)

{

	struct blkio_policy_node *pn;



	pn = blkio_policy_search_node(blkcg, dev);

	if (pn)

		return pn->weight;

	else

		return blkcg->weight;

}

EXPORT_SYMBOL_GPL(blkcg_get_weight);





static int blkiocg_weight_device_write(struct cgroup *cgrp, struct cftype *cft,

				       const char *buffer)

{

	int ret = 0;

	char *buf;

	struct blkio_policy_node *newpn, *pn;

	struct blkio_cgroup *blkcg;

	struct blkio_group *blkg;

	int keep_newpn = 0;

	struct hlist_node *n;

	struct blkio_policy_type *blkiop;



	buf = kstrdup(buffer, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);

	if (!newpn) {

		ret = -ENOMEM;

		goto free_buf;

	}



	ret = blkio_policy_parse_and_set(buf, newpn);

	if (ret)

		goto free_newpn;



	blkcg = cgroup_to_blkio_cgroup(cgrp);



	spin_lock_irq(&blkcg->lock);



	pn = blkio_policy_search_node(blkcg, newpn->dev);

	if (!pn) {

		if (newpn->weight != 0) {

			blkio_policy_insert_node(blkcg, newpn);

			keep_newpn = 1;

		}

		spin_unlock_irq(&blkcg->lock);

		goto update_io_group;

	}



	if (newpn->weight == 0) {

		/* weight == 0 means deleteing a specific weight */

		blkio_policy_delete_node(pn);

		spin_unlock_irq(&blkcg->lock);

		goto update_io_group;

	}

	spin_unlock_irq(&blkcg->lock);



	pn->weight = newpn->weight;



update_io_group:

	/* update weight for each cfqg */

	spin_lock(&blkio_list_lock);

	spin_lock_irq(&blkcg->lock);



	hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {

		if (newpn->dev == blkg->dev) {

			list_for_each_entry(blkiop, &blkio_list, list)

				blkiop->ops.blkio_update_group_weight_fn(blkg,

							 newpn->weight ?

							 newpn->weight :

							 blkcg->weight);

		}

	}



	spin_unlock_irq(&blkcg->lock);

	spin_unlock(&blkio_list_lock);



free_newpn:

	if (!keep_newpn)

		kfree(newpn);

free_buf:

	kfree(buf);

	return ret;

}



static int blkiocg_weight_device_read(struct cgroup *cgrp, struct cftype *cft,

				      struct seq_file *m)

{

	struct blkio_cgroup *blkcg;

	struct blkio_policy_node *pn;



	seq_printf(m, "dev\tweight\n");



	blkcg = cgroup_to_blkio_cgroup(cgrp);

	if (list_empty(&blkcg->policy_list))

		goto out;



	spin_lock_irq(&blkcg->lock);

	list_for_each_entry(pn, &blkcg->policy_list, node) {

		seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),

			   MINOR(pn->dev), pn->weight);

	}

	spin_unlock_irq(&blkcg->lock);



out:

	return 0;

}



struct cftype blkio_files[] = {

	{

		.name = "weight_device",

		.read_seq_string = blkiocg_weight_device_read,

		.write_string = blkiocg_weight_device_write,

		.max_write_len = 256,

	},

	{

		.name = "weight",

		.read_u64 = blkiocg_weight_read,
@@ -690,6 +919,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) 
	struct blkio_group *blkg;

	void *key;

	struct blkio_policy_type *blkiop;

	struct blkio_policy_node *pn, *pntmp;



	rcu_read_lock();

remove_entry:
@@ -720,7 +950,12 @@ remove_entry: 
		blkiop->ops.blkio_unlink_group_fn(key, blkg);

	spin_unlock(&blkio_list_lock);

	goto remove_entry;



done:

	list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {

		blkio_policy_delete_node(pn);

		kfree(pn);

	}

	free_css_id(&blkio_subsys, &blkcg->css);

	rcu_read_unlock();

	if (blkcg != &blkio_root_cgroup)
@@ -751,6 +986,7 @@ done: 
	spin_lock_init(&blkcg->lock);

	INIT_HLIST_HEAD(&blkcg->blkg_list);



	INIT_LIST_HEAD(&blkcg->policy_list);

	return &blkcg->css;

}

block/blk-cgroup.h

+10 −0
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ struct blkio_cgroup { 
	unsigned int weight;

	spinlock_t lock;

	struct hlist_head blkg_list;

	struct list_head policy_list; /* list of blkio_policy_node */

};



struct blkio_group_stats {
@@ -119,6 +120,15 @@ struct blkio_group { 
	struct blkio_group_stats stats;

};



struct blkio_policy_node {

	struct list_head node;

	dev_t dev;

	unsigned int weight;

};



extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,

				     dev_t dev);



typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);

typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,

						unsigned int weight);

block/cfq-iosched.c

+1 −1
Original line number Diff line number Diff line
@@ -952,7 +952,6 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) 
	if (!cfqg)

		goto done;



	cfqg->weight = blkcg->weight;

	for_each_cfqg_st(cfqg, i, j, st)

		*st = CFQ_RB_ROOT;

	RB_CLEAR_NODE(&cfqg->rb_node);
@@ -970,6 +969,7 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create) 
	sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);

	blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,

					MKDEV(major, minor));

	cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);



	/* Add group on cfqd list */

	hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);

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