From 03aa264ac15637b6f98374270bcdf31400965505 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 5 Mar 2012 13:15:19 -0800 Subject: blkcg: let blkcg core manage per-queue blkg list and counter With the previous patch to move blkg list heads and counters to request_queue and blkg, logic to manage them in both policies are almost identical and can be moved to blkcg core. This patch moves blkg link logic into blkg_lookup_create(), implements common blkg unlink code in blkg_destroy(), and updates blkg_destory_all() so that it's policy specific and can skip root group. The updated blkg_destroy_all() is now used to both clear queue for bypassing and elv switching, and release all blkgs on q exit. This patch introduces a race window where policy [de]registration may race against queue blkg clearing. This can only be a problem on cfq unload and shouldn't be a real problem in practice (and we have many other places where this race already exists). Future patches will remove these unlikely races. Signed-off-by: Tejun Heo Cc: Vivek Goyal Signed-off-by: Jens Axboe --- block/blk-cgroup.h | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'block/blk-cgroup.h') diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index ae96f196d469..83ce5fa0a604 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -196,11 +196,6 @@ struct blkio_group { }; typedef void (blkio_init_group_fn)(struct blkio_group *blkg); -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); typedef void (blkio_update_group_weight_fn)(struct request_queue *q, struct blkio_group *blkg, unsigned int weight); typedef void (blkio_update_group_read_bps_fn)(struct request_queue *q, @@ -214,9 +209,6 @@ typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q, struct blkio_policy_ops { blkio_init_group_fn *blkio_init_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; blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn; blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn; @@ -238,7 +230,8 @@ extern void blkcg_exit_queue(struct request_queue *q); /* Blkio controller policy registration */ extern void blkio_policy_register(struct blkio_policy_type *); extern void blkio_policy_unregister(struct blkio_policy_type *); -extern void blkg_destroy_all(struct request_queue *q); +extern void blkg_destroy_all(struct request_queue *q, + enum blkio_policy_id plid, bool destroy_root); /** * blkg_to_pdata - get policy private data @@ -319,7 +312,9 @@ static inline void blkcg_drain_queue(struct request_queue *q) { } static inline void blkcg_exit_queue(struct request_queue *q) { } static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { } static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { } -static inline void blkg_destroy_all(struct request_queue *q) { } +static inline void blkg_destroy_all(struct request_queue *q, + enum blkio_policy_id plid, + bool destory_root) { } static inline void *blkg_to_pdata(struct blkio_group *blkg, struct blkio_policy_type *pol) { return NULL; } -- cgit v1.2.3