From 67523c48aa74d5637848edeccf285af1c60bf14a Mon Sep 17 00:00:00 2001 From: Ben Blum Date: Wed, 10 Mar 2010 15:22:11 -0800 Subject: 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: Ben Blum Cc: Li Zefan Cc: Paul Menage Cc: "David S. Miller" Cc: KAMEZAWA Hiroyuki Cc: Lai Jiangshan Cc: Vivek Goyal Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- block/Kconfig | 2 +- block/Kconfig.iosched | 2 +- block/blk-cgroup.c | 53 +++++++++++++++++++++++++++++++++++++++------------ block/blk-cgroup.h | 10 ++++++++-- 4 files changed, 51 insertions(+), 16 deletions(-) (limited to 'block') diff --git a/block/Kconfig b/block/Kconfig index e20fbde0875c6..62a5921321cd4 100644 --- a/block/Kconfig +++ b/block/Kconfig @@ -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--- diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched index b71abfb0d7269..fc71cf071fb2c 100644 --- a/block/Kconfig.iosched +++ b/block/Kconfig.iosched @@ -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. diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index c85d74cae2002..4b686ad08eaaa 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -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), @@ -253,7 +278,8 @@ remove_entry: done: free_css_id(&blkio_subsys, &blkcg->css); rcu_read_unlock(); - kfree(blkcg); + if (blkcg != &blkio_root_cgroup) + kfree(blkcg); } static struct cgroup_subsys_state * @@ -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"); diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 84bf745fa7757..8ccc20464daec 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -15,7 +15,13 @@ #include -#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, -- cgit v1.2.3