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authorTejun Heo <tj@kernel.org>2014-09-08 08:15:20 +0900
committerJens Axboe <axboe@fb.com>2014-09-08 09:55:37 -0600
commitf4da80727cfbc3590d95ff17ef8db96e6f1483a4 (patch)
treecd073c26cb66e6d2f8640c3aabb412ff22946b63
parent55872c5a3c01f0fe7b5298d19e24e237f5b5ff06 (diff)
blkcg: remove blkcg->id
blkcg->id is a unique id given to each blkcg; however, the cgroup_subsys_state which each blkcg embeds already has ->serial_nr which can be used for the same purpose. Drop blkcg->id and replace its uses with blkcg->css.serial_nr. Rename cfq_cgroup->blkcg_id to ->blkcg_serial_nr and @id in check_blkcg_changed() to @serial_nr for consistency. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--block/blk-cgroup.c2
-rw-r--r--block/blk-cgroup.h3
-rw-r--r--block/cfq-iosched.c10
3 files changed, 5 insertions, 10 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index e17da947f6bd..0ac817b750db 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -822,7 +822,6 @@ static void blkcg_css_free(struct cgroup_subsys_state *css)
static struct cgroup_subsys_state *
blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
{
- static atomic64_t id_seq = ATOMIC64_INIT(0);
struct blkcg *blkcg;
if (!parent_css) {
@@ -836,7 +835,6 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
blkcg->cfq_weight = CFQ_WEIGHT_DEFAULT;
blkcg->cfq_leaf_weight = CFQ_WEIGHT_DEFAULT;
- blkcg->id = atomic64_inc_return(&id_seq); /* root is 0, start from 1 */
done:
spin_lock_init(&blkcg->lock);
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index d3fd7aa3d2a3..c567865b5f1d 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -50,9 +50,6 @@ struct blkcg {
struct blkcg_gq *blkg_hint;
struct hlist_head blkg_list;
- /* for policies to test whether associated blkcg has changed */
- uint64_t id;
-
/* TODO: per-policy storage in blkcg */
unsigned int cfq_weight; /* belongs to cfq */
unsigned int cfq_leaf_weight;
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index cadc37841744..900f569afcc5 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -299,7 +299,7 @@ struct cfq_io_cq {
struct cfq_ttime ttime;
int ioprio; /* the current ioprio */
#ifdef CONFIG_CFQ_GROUP_IOSCHED
- uint64_t blkcg_id; /* the current blkcg ID */
+ uint64_t blkcg_serial_nr; /* the current blkcg serial */
#endif
};
@@ -3534,17 +3534,17 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
{
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *sync_cfqq;
- uint64_t id;
+ uint64_t serial_nr;
rcu_read_lock();
- id = bio_blkcg(bio)->id;
+ serial_nr = bio_blkcg(bio)->css.serial_nr;
rcu_read_unlock();
/*
* Check whether blkcg has changed. The condition may trigger
* spuriously on a newly created cic but there's no harm.
*/
- if (unlikely(!cfqd) || likely(cic->blkcg_id == id))
+ if (unlikely(!cfqd) || likely(cic->blkcg_serial_nr == serial_nr))
return;
sync_cfqq = cic_to_cfqq(cic, 1);
@@ -3558,7 +3558,7 @@ static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
cfq_put_queue(sync_cfqq);
}
- cic->blkcg_id = id;
+ cic->blkcg_serial_nr = serial_nr;
}
#else
static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) { }