[PATCH 01/13] blk-throttle: Do the new group initialization with the help of a function

Vivek Goyal
2011-05-19T19:38:50Z

Group initialization code seems to be at two places. root group
initialization in blk_throtl_init() and dynamically allocated group
in throtl_find_alloc_tg(). Create a common function and use at both
the places.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
block/blk-throttle.c | 64 +++++++++++++++++++++++++++----------------------
1 files changed, 35 insertions(+), 29 deletions(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 252a81a..fa9a900 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -159,6 +159,35 @@ static void throtl_put_tg(struct throtl_grp *tg)
kfree(tg);
}

+static void throtl_init_group(struct throtl_grp *tg)
+{
+ INIT_HLIST_NODE(&tg->tg_node);
+ RB_CLEAR_NODE(&tg->rb_node);
+ bio_list_init(&tg->bio_lists[0]);
+ bio_list_init(&tg->bio_lists[1]);
+ tg->limits_changed = false;
+
+ /* Practically unlimited BW */
+ tg->bps[0] = tg->bps[1] = -1;
+ tg->iops[0] = tg->iops[1] = -1;
+
+ /*
+ * Take the initial reference that will be released on destroy
+ * This can be thought of a joint reference by cgroup and
+ * request queue which will be dropped by either request queue
+ * exit or cgroup deletion path depending on who is exiting first.
+ */
+ atomic_set(&tg->ref, 1);
+}
+
+/* Should be called with rcu read lock held (needed for blkcg) */
+static void
+throtl_add_group_to_td_list(struct throtl_data *td, struct throtl_grp *tg)
+{
+ hlist_add_head(&tg->tg_node, &td->tg_list);
+ td->nr_undestroyed_grps++;
+}
+
static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
struct blkio_cgroup *blkcg)
{
@@ -196,19 +225,7 @@ static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
if (!tg)
goto done;

- INIT_HLIST_NODE(&tg->tg_node);
- RB_CLEAR_NODE(&tg->rb_node);
- bio_list_init(&tg->bio_lists[0]);
- bio_list_init(&tg->bio_lists[1]);
- td->limits_changed = false;
-
- /*
- * Take the initial reference that will be released on destroy
- * This can be thought of a joint reference by cgroup and
- * request queue which will be dropped by either request queue
- * exit or cgroup deletion path depending on who is exiting first.
- */
- atomic_set(&tg->ref, 1);
+ throtl_init_group(tg);

/* Add group onto cgroup list */
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
@@ -220,8 +237,7 @@ static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
tg->iops[READ] = blkcg_get_read_iops(blkcg, tg->blkg.dev);
tg->iops[WRITE] = blkcg_get_write_iops(blkcg, tg->blkg.dev);

- hlist_add_head(&tg->tg_node, &td->tg_list);
- td->nr_undestroyed_grps++;
+ throtl_add_group_to_td_list(td, tg);
done:
return tg;
}
@@ -1060,18 +1076,11 @@ int blk_throtl_init(struct request_queue *q)
INIT_HLIST_HEAD(&td->tg_list);
td->tg_service_tree = THROTL_RB_ROOT;
td->limits_changed = false;
+ INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);

/* Init root group */
tg = &td->root_tg;
- INIT_HLIST_NODE(&tg->tg_node);
- RB_CLEAR_NODE(&tg->rb_node);
- bio_list_init(&tg->bio_lists[0]);
- bio_list_init(&tg->bio_lists[1]);
-
- /* Practically unlimited BW */
- tg->bps[0] = tg->bps[1] = -1;
- tg->iops[0] = tg->iops[1] = -1;
- td->limits_changed = false;
+ throtl_init_group(tg);

/*
* Set root group reference to 2. One reference will be dropped when
@@ -1080,16 +1089,13 @@ int blk_throtl_init(struct request_queue *q)
* as it is statically allocated and gets destroyed when throtl_data
* goes away.
*/
- atomic_set(&tg->ref, 2);
- hlist_add_head(&tg->tg_node, &td->tg_list);
- td->nr_undestroyed_grps++;
-
- INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
+ atomic_inc(&tg->ref);

rcu_read_lock();
blkiocg_add_blkio_group(&blkio_root_cgroup, &tg->blkg, (void *)td,
0, BLKIO_POLICY_THROTL);
rcu_read_unlock();
+ throtl_add_group_to_td_list(td, tg);

/* Attach throtl data to request queue */
td->queue = q;
--
1.7.4.4