To prepare for hierarchy support, this patch adds
throtl_service_queue->service_sq which points to the arent
service_queue. Currently, for all service_queues embedded in
throtl_grps, it points to throtl_data->service_queue. As
throtl_data->service_queue doesn't have a parent its parent_sq is set
to NULL.
There are a number of functions which take both throtl_grp *tg and
throtl_service_queue *parent_sq. With this patch, the parent
service_queue can be determined from @tg and the @parent_sq arguments
are removed.
This patch doesn't make any behavior differences.
Signed-off-by: Tejun Heo <t...@kernel.org>
---
block/blk-throttle.c | 81 +++++++++++++++++++++++++---------------------------
1 file changed, 39 insertions(+), 42 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 65b8b38..64d1923 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -27,6 +27,8 @@ static struct blkcg_policy blkcg_policy_throtl;
static struct workqueue_struct *kthrotld_workqueue;
struct throtl_service_queue {
+ struct throtl_service_queue *parent_sq; /* the parent service_queue */
+
/*
* Bios queued directly to this service_queue or dispatched from
* children throtl_grp's.
@@ -197,21 +199,24 @@ alloc_stats:
}
/* init a service_queue, assumes the caller zeroed it */
-static void throtl_service_queue_init(struct throtl_service_queue *sq)
+static void throtl_service_queue_init(struct throtl_service_queue *sq,
+ struct throtl_service_queue *parent_sq)
{
bio_list_init(&sq->bio_lists[0]);
bio_list_init(&sq->bio_lists[1]);
sq->pending_tree = RB_ROOT;
+ sq->parent_sq = parent_sq;
}
static void throtl_pd_init(struct blkcg_gq *blkg)
{
struct throtl_grp *tg = blkg_to_tg(blkg);
+ struct throtl_data *td = blkg->q->td;
unsigned long flags;
- throtl_service_queue_init(&tg->service_queue);
+ throtl_service_queue_init(&tg->service_queue, &td->service_queue);
RB_CLEAR_NODE(&tg->rb_node);
- tg->td = blkg->q->td;
+ tg->td = td;
tg->bps[READ] = -1;
tg->bps[WRITE] = -1;
@@ -339,9 +344,9 @@ static void update_min_dispatch_time(struct
throtl_service_queue *parent_sq)
parent_sq->first_pending_disptime = tg->disptime;
}
-static void tg_service_queue_add(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void tg_service_queue_add(struct throtl_grp *tg)
{
+ struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq;
struct rb_node **node = &parent_sq->pending_tree.rb_node;
struct rb_node *parent = NULL;
struct throtl_grp *__tg;
@@ -367,33 +372,29 @@ static void tg_service_queue_add(struct throtl_grp *tg,
rb_insert_color(&tg->rb_node, &parent_sq->pending_tree);
}
-static void __throtl_enqueue_tg(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void __throtl_enqueue_tg(struct throtl_grp *tg)
{
- tg_service_queue_add(tg, parent_sq);
+ tg_service_queue_add(tg);
tg->flags |= THROTL_TG_PENDING;
- parent_sq->nr_pending++;
+ tg->service_queue.parent_sq->nr_pending++;
}
-static void throtl_enqueue_tg(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void throtl_enqueue_tg(struct throtl_grp *tg)
{
if (!(tg->flags & THROTL_TG_PENDING))
- __throtl_enqueue_tg(tg, parent_sq);
+ __throtl_enqueue_tg(tg);
}
-static void __throtl_dequeue_tg(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void __throtl_dequeue_tg(struct throtl_grp *tg)
{
- throtl_rb_erase(&tg->rb_node, parent_sq);
+ throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq);
tg->flags &= ~THROTL_TG_PENDING;
}
-static void throtl_dequeue_tg(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void throtl_dequeue_tg(struct throtl_grp *tg)
{
if (tg->flags & THROTL_TG_PENDING)
- __throtl_dequeue_tg(tg, parent_sq);
+ __throtl_dequeue_tg(tg);
}
/* Call with queue lock held */
@@ -707,8 +708,7 @@ static void throtl_charge_bio(struct throtl_grp *tg, struct
bio *bio)
throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw);
}
-static void throtl_add_bio_tg(struct bio *bio, struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void throtl_add_bio_tg(struct bio *bio, struct throtl_grp *tg)
{
struct throtl_service_queue *sq = &tg->service_queue;
bool rw = bio_data_dir(bio);
@@ -727,11 +727,10 @@ static void throtl_add_bio_tg(struct bio *bio, struct
throtl_grp *tg,
blkg_get(tg_to_blkg(tg));
sq->nr_queued[rw]++;
tg->td->nr_queued[rw]++;
- throtl_enqueue_tg(tg, parent_sq);
+ throtl_enqueue_tg(tg);
}
-static void tg_update_disptime(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static void tg_update_disptime(struct throtl_grp *tg)
{
struct throtl_service_queue *sq = &tg->service_queue;
unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime;
@@ -747,16 +746,15 @@ static void tg_update_disptime(struct throtl_grp *tg,
disptime = jiffies + min_wait;
/* Update dispatch time */
- throtl_dequeue_tg(tg, parent_sq);
+ throtl_dequeue_tg(tg);
tg->disptime = disptime;
- throtl_enqueue_tg(tg, parent_sq);
+ throtl_enqueue_tg(tg);
/* see throtl_add_bio_tg() */
tg->flags &= ~THROTL_TG_WAS_EMPTY;
}
-static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw,
- struct throtl_service_queue *parent_sq)
+static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw)
{
struct throtl_service_queue *sq = &tg->service_queue;
struct bio *bio;
@@ -770,14 +768,13 @@ static void tg_dispatch_one_bio(struct throtl_grp *tg,
bool rw,
tg->td->nr_queued[rw]--;
throtl_charge_bio(tg, bio);
- bio_list_add(&parent_sq->bio_lists[rw], bio);
+ bio_list_add(&sq->parent_sq->bio_lists[rw], bio);
bio->bi_rw |= REQ_THROTTLED;
throtl_trim_slice(tg, rw);
}
-static int throtl_dispatch_tg(struct throtl_grp *tg,
- struct throtl_service_queue *parent_sq)
+static int throtl_dispatch_tg(struct throtl_grp *tg)
{
struct throtl_service_queue *sq = &tg->service_queue;
unsigned int nr_reads = 0, nr_writes = 0;
@@ -790,7 +787,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg,
while ((bio = bio_list_peek(&sq->bio_lists[READ])) &&
tg_may_dispatch(tg, bio, NULL)) {
- tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq);
+ tg_dispatch_one_bio(tg, bio_data_dir(bio));
nr_reads++;
if (nr_reads >= max_nr_reads)
@@ -800,7 +797,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg,
while ((bio = bio_list_peek(&sq->bio_lists[WRITE])) &&
tg_may_dispatch(tg, bio, NULL)) {
- tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq);
+ tg_dispatch_one_bio(tg, bio_data_dir(bio));
nr_writes++;
if (nr_writes >= max_nr_writes)
@@ -824,12 +821,12 @@ static int throtl_select_dispatch(struct
throtl_service_queue *parent_sq)
if (time_before(jiffies, tg->disptime))
break;
- throtl_dequeue_tg(tg, parent_sq);
+ throtl_dequeue_tg(tg);
- nr_disp += throtl_dispatch_tg(tg, parent_sq);
+ nr_disp += throtl_dispatch_tg(tg);
if (sq->nr_queued[0] || sq->nr_queued[1])
- tg_update_disptime(tg, parent_sq);
+ tg_update_disptime(tg);
if (nr_disp >= throtl_quantum)
break;
@@ -991,7 +988,7 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype
*cft, const char *buf,
throtl_start_new_slice(tg, 1);
if (tg->flags & THROTL_TG_PENDING) {
- tg_update_disptime(tg, &td->service_queue);
+ tg_update_disptime(tg);
throtl_schedule_next_dispatch(td);
}
@@ -1145,12 +1142,12 @@ queue_bio:
sq->nr_queued[READ], sq->nr_queued[WRITE]);
bio_associate_current(bio);
- throtl_add_bio_tg(bio, tg, &q->td->service_queue);
+ throtl_add_bio_tg(bio, tg);
throttled = true;
/* update @tg's dispatch time if @tg was empty before @bio */
if (tg->flags & THROTL_TG_WAS_EMPTY) {
- tg_update_disptime(tg, &td->service_queue);
+ tg_update_disptime(tg);
throtl_schedule_next_dispatch(td);
}
@@ -1182,12 +1179,12 @@ void blk_throtl_drain(struct request_queue *q)
while ((tg = throtl_rb_first(parent_sq))) {
struct throtl_service_queue *sq = &tg->service_queue;
- throtl_dequeue_tg(tg, parent_sq);
+ throtl_dequeue_tg(tg);
while ((bio = bio_list_peek(&sq->bio_lists[READ])))
- tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq);
+ tg_dispatch_one_bio(tg, bio_data_dir(bio));
while ((bio = bio_list_peek(&sq->bio_lists[WRITE])))
- tg_dispatch_one_bio(tg, bio_data_dir(bio), parent_sq);
+ tg_dispatch_one_bio(tg, bio_data_dir(bio));
}
spin_unlock_irq(q->queue_lock);
@@ -1208,7 +1205,7 @@ int blk_throtl_init(struct request_queue *q)
return -ENOMEM;
INIT_DELAYED_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn);
- throtl_service_queue_init(&td->service_queue);
+ throtl_service_queue_init(&td->service_queue, NULL);
q->td = td;
td->queue = q;
--
1.8.1.4
--
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