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blk-throttle: add throtl_service_queue->parent_sq

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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 <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
This commit is contained in:
Tejun Heo 2013-05-14 13:52:36 -07:00
parent 0e9f4164ba
commit 77216b0484
1 changed files with 39 additions and 42 deletions
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81
block/blk-throttle.c
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@ -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 @@ static void tg_stats_alloc_fn(struct work_struct *work)
}
/* 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);
}
@ -1142,12 +1139,12 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *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);
}
@ -1179,12 +1176,12 @@ 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);
@ -1205,7 +1202,7 @@ 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;