From cd1604fab4f95f7cfc227d3955fd7ae14da61f38 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 5 Mar 2012 13:15:06 -0800 Subject: blkcg: factor out blkio_group creation Currently both blk-throttle and cfq-iosched implement their own blkio_group creation code in throtl_get_tg() and cfq_get_cfqg(). This patch factors out the common code into blkg_lookup_create(), which returns ERR_PTR value so that transitional failures due to queue bypass can be distinguished from other failures. * New plkio_policy_ops methods blkio_alloc_group_fn() and blkio_link_group_fn added. Both are transitional and will be removed once the blkg management code is fully moved into blk-cgroup.c. * blkio_alloc_group_fn() allocates policy-specific blkg which is usually a larger data structure with blkg as the first entry and intiailizes it. Note that initialization of blkg proper, including percpu stats, is responsibility of blk-cgroup proper. Note that default config (weight, bps...) initialization is done from this method; otherwise, we end up violating locking order between blkcg and q locks via blkcg_get_CONF() functions. * blkio_link_group_fn() is called under queue_lock and responsible for linking the blkg to the queue. blkcg side is handled by blk-cgroup proper. * The common blkg creation function is named blkg_lookup_create() and blkiocg_lookup_group() is renamed to blkg_lookup() for consistency. Also, throtl / cfq related functions are similarly [re]named for consistency. This simplifies blkcg policy implementations and enables further cleanup. -v2: Vivek noticed that blkg_lookup_create() incorrectly tested blk_queue_dead() instead of blk_queue_bypass() leading a user of the function ending up creating a new blkg on bypassing queue. This is a bug introduced while relocating bypass patches before this one. Fixed. -v3: ERR_PTR patch folded into this one. @for_root added to blkg_lookup_create() to allow creating root group on a bypassed queue during elevator switch. Signed-off-by: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.h | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) (limited to 'block/blk-cgroup.h') diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 562fa55d97b1..2600ae7e6f60 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -204,6 +204,10 @@ extern unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, extern unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev); +typedef struct blkio_group *(blkio_alloc_group_fn)(struct request_queue *q, + struct blkio_cgroup *blkcg); +typedef void (blkio_link_group_fn)(struct request_queue *q, + struct blkio_group *blkg); typedef void (blkio_unlink_group_fn)(struct request_queue *q, struct blkio_group *blkg); typedef bool (blkio_clear_queue_fn)(struct request_queue *q); @@ -219,6 +223,8 @@ typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q, struct blkio_group *blkg, unsigned int write_iops); struct blkio_policy_ops { + blkio_alloc_group_fn *blkio_alloc_group_fn; + blkio_link_group_fn *blkio_link_group_fn; blkio_unlink_group_fn *blkio_unlink_group_fn; blkio_clear_queue_fn *blkio_clear_queue_fn; blkio_update_group_weight_fn *blkio_update_group_weight_fn; @@ -307,14 +313,14 @@ static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {} extern struct blkio_cgroup blkio_root_cgroup; extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup); extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk); -extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, - struct blkio_group *blkg, struct request_queue *q, dev_t dev, - enum blkio_policy_id plid); -extern int blkio_alloc_blkg_stats(struct blkio_group *blkg); extern int blkiocg_del_blkio_group(struct blkio_group *blkg); -extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, - struct request_queue *q, - enum blkio_policy_id plid); +extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg, + struct request_queue *q, + enum blkio_policy_id plid); +struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg, + struct request_queue *q, + enum blkio_policy_id plid, + bool for_root); void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time, unsigned long unaccounted_time); @@ -335,17 +341,11 @@ cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; } static inline struct blkio_cgroup * task_blkio_cgroup(struct task_struct *tsk) { return NULL; } -static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, - struct blkio_group *blkg, void *key, dev_t dev, - enum blkio_policy_id plid) {} - -static inline int blkio_alloc_blkg_stats(struct blkio_group *blkg) { return 0; } - static inline int blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; } -static inline struct blkio_group * -blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; } +static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg, + void *key) { return NULL; } static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time, unsigned long unaccounted_time) -- cgit v1.2.3