blk-throttle: rename throtl_rb_root to throtl_service_queue

throtl_rb_root will be expanded to cover more roles for hierarchy
support.  Rename it to throtl_service_queue and make its fields more
descriptive.

* rb		-> pending_tree
* left		-> first_pending
* count		-> nr_pending
* min_disptime	-> first_pending_disptime

This patch is purely cosmetic.

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 13:52:32 -07:00
parent 6a525600ff
commit c9e0332e87

View File

@ -26,15 +26,15 @@ static struct blkcg_policy blkcg_policy_throtl;
/* A workqueue to queue throttle related work */
static struct workqueue_struct *kthrotld_workqueue;
struct throtl_rb_root {
struct rb_root rb;
struct rb_node *left;
unsigned int count;
unsigned long min_disptime;
struct throtl_service_queue {
struct rb_root pending_tree; /* RB tree of active tgs */
struct rb_node *first_pending; /* first node in the tree */
unsigned int nr_pending; /* # queued in the tree */
unsigned long first_pending_disptime; /* disptime of the first tg */
};
#define THROTL_RB_ROOT (struct throtl_rb_root) { .rb = RB_ROOT, .left = NULL, \
.count = 0, .min_disptime = 0}
#define THROTL_SERVICE_QUEUE_INITIALIZER \
(struct throtl_service_queue){ .pending_tree = RB_ROOT }
#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)
@ -50,7 +50,7 @@ struct throtl_grp {
/* must be the first member */
struct blkg_policy_data pd;
/* active throtl group service_tree member */
/* active throtl group service_queue member */
struct rb_node rb_node;
/*
@ -93,7 +93,7 @@ struct throtl_grp {
struct throtl_data
{
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
struct throtl_service_queue service_queue;
struct request_queue *queue;
@ -296,17 +296,17 @@ static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
return tg;
}
static struct throtl_grp *throtl_rb_first(struct throtl_rb_root *root)
static struct throtl_grp *throtl_rb_first(struct throtl_service_queue *sq)
{
/* Service tree is empty */
if (!root->count)
if (!sq->nr_pending)
return NULL;
if (!root->left)
root->left = rb_first(&root->rb);
if (!sq->first_pending)
sq->first_pending = rb_first(&sq->pending_tree);
if (root->left)
return rb_entry_tg(root->left);
if (sq->first_pending)
return rb_entry_tg(sq->first_pending);
return NULL;
}
@ -317,29 +317,29 @@ static void rb_erase_init(struct rb_node *n, struct rb_root *root)
RB_CLEAR_NODE(n);
}
static void throtl_rb_erase(struct rb_node *n, struct throtl_rb_root *root)
static void throtl_rb_erase(struct rb_node *n, struct throtl_service_queue *sq)
{
if (root->left == n)
root->left = NULL;
rb_erase_init(n, &root->rb);
--root->count;
if (sq->first_pending == n)
sq->first_pending = NULL;
rb_erase_init(n, &sq->pending_tree);
--sq->nr_pending;
}
static void update_min_dispatch_time(struct throtl_rb_root *st)
static void update_min_dispatch_time(struct throtl_service_queue *sq)
{
struct throtl_grp *tg;
tg = throtl_rb_first(st);
tg = throtl_rb_first(sq);
if (!tg)
return;
st->min_disptime = tg->disptime;
sq->first_pending_disptime = tg->disptime;
}
static void
tg_service_tree_add(struct throtl_rb_root *st, struct throtl_grp *tg)
static void tg_service_queue_add(struct throtl_service_queue *sq,
struct throtl_grp *tg)
{
struct rb_node **node = &st->rb.rb_node;
struct rb_node **node = &sq->pending_tree.rb_node;
struct rb_node *parent = NULL;
struct throtl_grp *__tg;
unsigned long key = tg->disptime;
@ -358,19 +358,19 @@ tg_service_tree_add(struct throtl_rb_root *st, struct throtl_grp *tg)
}
if (left)
st->left = &tg->rb_node;
sq->first_pending = &tg->rb_node;
rb_link_node(&tg->rb_node, parent, node);
rb_insert_color(&tg->rb_node, &st->rb);
rb_insert_color(&tg->rb_node, &sq->pending_tree);
}
static void __throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
{
struct throtl_rb_root *st = &td->tg_service_tree;
struct throtl_service_queue *sq = &td->service_queue;
tg_service_tree_add(st, tg);
tg_service_queue_add(sq, tg);
throtl_mark_tg_on_rr(tg);
st->count++;
sq->nr_pending++;
}
static void throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
@ -381,7 +381,7 @@ static void throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg)
static void __throtl_dequeue_tg(struct throtl_data *td, struct throtl_grp *tg)
{
throtl_rb_erase(&tg->rb_node, &td->tg_service_tree);
throtl_rb_erase(&tg->rb_node, &td->service_queue);
throtl_clear_tg_on_rr(tg);
}
@ -403,18 +403,18 @@ static void throtl_schedule_delayed_work(struct throtl_data *td,
static void throtl_schedule_next_dispatch(struct throtl_data *td)
{
struct throtl_rb_root *st = &td->tg_service_tree;
struct throtl_service_queue *sq = &td->service_queue;
/* any pending children left? */
if (!st->count)
if (!sq->nr_pending)
return;
update_min_dispatch_time(st);
update_min_dispatch_time(sq);
if (time_before_eq(st->min_disptime, jiffies))
if (time_before_eq(sq->first_pending_disptime, jiffies))
throtl_schedule_delayed_work(td, 0);
else
throtl_schedule_delayed_work(td, (st->min_disptime - jiffies));
throtl_schedule_delayed_work(td, sq->first_pending_disptime - jiffies);
}
static inline void
@ -794,10 +794,10 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
{
unsigned int nr_disp = 0;
struct throtl_grp *tg;
struct throtl_rb_root *st = &td->tg_service_tree;
struct throtl_service_queue *sq = &td->service_queue;
while (1) {
tg = throtl_rb_first(st);
tg = throtl_rb_first(sq);
if (!tg)
break;
@ -1145,7 +1145,7 @@ void blk_throtl_drain(struct request_queue *q)
__releases(q->queue_lock) __acquires(q->queue_lock)
{
struct throtl_data *td = q->td;
struct throtl_rb_root *st = &td->tg_service_tree;
struct throtl_service_queue *sq = &td->service_queue;
struct throtl_grp *tg;
struct bio_list bl;
struct bio *bio;
@ -1154,7 +1154,7 @@ void blk_throtl_drain(struct request_queue *q)
bio_list_init(&bl);
while ((tg = throtl_rb_first(st))) {
while ((tg = throtl_rb_first(sq))) {
throtl_dequeue_tg(td, tg);
while ((bio = bio_list_peek(&tg->bio_lists[READ])))
@ -1179,7 +1179,7 @@ int blk_throtl_init(struct request_queue *q)
if (!td)
return -ENOMEM;
td->tg_service_tree = THROTL_RB_ROOT;
td->service_queue = THROTL_SERVICE_QUEUE_INITIALIZER;
INIT_DELAYED_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn);
q->td = td;