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blkcg: add request_queue->root_blkg 

With per-queue policy activation, root blkg creation will be moved to
blkcg core.  Add q->root_blkg in preparation.  For blk-throtl, this
replaces throtl_data->root_tg; however, cfq needs to keep
cfqd->root_group for !CONFIG_CFQ_GROUP_IOSCHED.

This is to prepare for per-queue policy activation and doesn't cause
any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Tejun Heo 2012-04-13 13:11:32 -07:00 committed by Jens Axboe
parent b82d4b197c
commit 03d8e11142
3 changed files with 15 additions and 7 deletions
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16
block/blk-throttle.c
View File

@ -97,7 +97,6 @@ struct throtl_data
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
struct throtl_grp *root_tg;
struct request_queue *queue;
/* Total Number of queued bios on READ and WRITE lists */
@ -131,6 +130,11 @@ static inline struct blkio_group *tg_to_blkg(struct throtl_grp *tg)
return pdata_to_blkg(tg);
}
static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
{
return blkg_to_tg(td->queue->root_blkg);
}
enum tg_state_flags {
THROTL_TG_FLAG_on_rr = 0, /* on round-robin busy list */
};
@ -261,7 +265,7 @@ throtl_grp *throtl_lookup_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
* Avoid lookup in this case
*/
if (blkcg == &blkio_root_cgroup)
return td->root_tg;
return td_root_tg(td);
return blkg_to_tg(blkg_lookup(blkcg, td->queue));
}
@ -277,7 +281,7 @@ static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
* Avoid lookup in this case
*/
if (blkcg == &blkio_root_cgroup) {
tg = td->root_tg;
tg = td_root_tg(td);
} else {
struct blkio_group *blkg;
@ -287,7 +291,7 @@ static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
if (!IS_ERR(blkg))
tg = blkg_to_tg(blkg);
else if (!blk_queue_dead(q))
tg = td->root_tg;
tg = td_root_tg(td);
}
return tg;
@ -1245,12 +1249,12 @@ int blk_throtl_init(struct request_queue *q)
blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
if (!IS_ERR(blkg))
td->root_tg = blkg_to_tg(blkg);
q->root_blkg = blkg;
spin_unlock_irq(q->queue_lock);
rcu_read_unlock();
if (!td->root_tg) {
if (!q->root_blkg) {
kfree(td);
return -ENOMEM;
}

4
block/cfq-iosched.c
View File

@ -3964,8 +3964,10 @@ static int cfq_init_queue(struct request_queue *q)
spin_lock_irq(q->queue_lock);
blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
if (!IS_ERR(blkg))
if (!IS_ERR(blkg)) {
q->root_blkg = blkg;
cfqd->root_group = blkg_to_cfqg(blkg);
}
spin_unlock_irq(q->queue_lock);
rcu_read_unlock();

2
include/linux/blkdev.h
View File

@ -31,6 +31,7 @@ struct blk_trace;
struct request;
struct sg_io_hdr;
struct bsg_job;
struct blkio_group;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
@ -369,6 +370,7 @@ struct request_queue {
struct list_head icq_list;
#ifdef CONFIG_BLK_CGROUP
struct blkio_group *root_blkg;
struct list_head blkg_list;
#endif