Commit 67523c48 authored by Ben Blum's avatar Ben Blum Committed by Linus Torvalds
Browse files

cgroups: blkio subsystem as module 



Modify the Block I/O cgroup subsystem to be able to be built as a module.
As the CFQ disk scheduler optionally depends on blk-cgroup, config options
in block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are
enhanced to support the new module dependency.

Signed-off-by: default avatarBen Blum <bblum@andrew.cmu.edu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8ca712ea

block/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -78,7 +78,7 @@ config BLK_DEV_INTEGRITY 
	Protection.  If in doubt, say N.



config BLK_CGROUP

	bool

	tristate

	depends on CGROUPS

	default n

	---help---

block/Kconfig.iosched

+1 −1
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ config IOSCHED_DEADLINE 


config IOSCHED_CFQ

	tristate "CFQ I/O scheduler"

	select BLK_CGROUP if CFQ_GROUP_IOSCHED

	default y

	---help---

	  The CFQ I/O scheduler tries to distribute bandwidth equally
@@ -35,7 +36,6 @@ config IOSCHED_CFQ 
config CFQ_GROUP_IOSCHED

	bool "CFQ Group Scheduling support"

	depends on IOSCHED_CFQ && CGROUPS

	select BLK_CGROUP

	default n

	---help---

	  Enable group IO scheduling in CFQ.

block/blk-cgroup.c

+41 −12
Original line number Diff line number Diff line
@@ -23,6 +23,31 @@ static LIST_HEAD(blkio_list); 
struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };

EXPORT_SYMBOL_GPL(blkio_root_cgroup);



static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,

						  struct cgroup *);

static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,

			      struct task_struct *, bool);

static void blkiocg_attach(struct cgroup_subsys *, struct cgroup *,

			   struct cgroup *, struct task_struct *, bool);

static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);

static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);



struct cgroup_subsys blkio_subsys = {

	.name = "blkio",

	.create = blkiocg_create,

	.can_attach = blkiocg_can_attach,

	.attach = blkiocg_attach,

	.destroy = blkiocg_destroy,

	.populate = blkiocg_populate,

#ifdef CONFIG_BLK_CGROUP

	/* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */

	.subsys_id = blkio_subsys_id,

#endif

	.use_id = 1,

	.module = THIS_MODULE,

};

EXPORT_SYMBOL_GPL(blkio_subsys);



struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)

{

	return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
@@ -253,6 +278,7 @@ remove_entry: 
done:

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

	rcu_read_unlock();

	if (blkcg != &blkio_root_cgroup)

		kfree(blkcg);

}
@@ -319,17 +345,6 @@ static void blkiocg_attach(struct cgroup_subsys *subsys, struct cgroup *cgroup, 
	task_unlock(tsk);

}



struct cgroup_subsys blkio_subsys = {

	.name = "blkio",

	.create = blkiocg_create,

	.can_attach = blkiocg_can_attach,

	.attach = blkiocg_attach,

	.destroy = blkiocg_destroy,

	.populate = blkiocg_populate,

	.subsys_id = blkio_subsys_id,

	.use_id = 1,

};



void blkio_policy_register(struct blkio_policy_type *blkiop)

{

	spin_lock(&blkio_list_lock);
@@ -345,3 +360,17 @@ void blkio_policy_unregister(struct blkio_policy_type *blkiop) 
	spin_unlock(&blkio_list_lock);

}

EXPORT_SYMBOL_GPL(blkio_policy_unregister);



static int __init init_cgroup_blkio(void)

{

	return cgroup_load_subsys(&blkio_subsys);

}



static void __exit exit_cgroup_blkio(void)

{

	cgroup_unload_subsys(&blkio_subsys);

}



module_init(init_cgroup_blkio);

module_exit(exit_cgroup_blkio);

MODULE_LICENSE("GPL");

block/blk-cgroup.h

+8 −2
Original line number Diff line number Diff line
@@ -15,7 +15,13 @@ 


#include <linux/cgroup.h>



#ifdef CONFIG_BLK_CGROUP

#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)



#ifndef CONFIG_BLK_CGROUP

/* When blk-cgroup is a module, its subsys_id isn't a compile-time constant */

extern struct cgroup_subsys blkio_subsys;

#define blkio_subsys_id blkio_subsys.subsys_id

#endif



struct blkio_cgroup {

	struct cgroup_subsys_state css;
@@ -91,7 +97,7 @@ static inline void blkiocg_update_blkio_group_dequeue_stats( 
			struct blkio_group *blkg, unsigned long dequeue) {}

#endif



#ifdef CONFIG_BLK_CGROUP

#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)

extern struct blkio_cgroup blkio_root_cgroup;

extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);

extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,

include/linux/iocontext.h

+1 −1
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ struct io_context { 
	unsigned short ioprio;

	unsigned short ioprio_changed;



#ifdef CONFIG_BLK_CGROUP

#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)

	unsigned short cgroup_changed;

#endif

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