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blk-throttle: move bio_lists[] and friends to throtl_service_queue

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throtl_service_queues will eventually form a tree which is anchored at
throtl_data->service_queue and queue bios will climb the tree to the
top service_queue to be executed.

This patch moves bio_lists[] and nr_queued[] from throtl_grp to its
service_queue to prepare for that.  As currently only the
throtl_data->service_queue is in use, this patch just ends up moving
throtl_grp->bio_lists[] and ->nr_queued[] to
throtl_grp->service_queue.bio_lists[] and ->nr_queued[] without making
any functional 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 13:52:35 -07:00
parent 49a2f1e3f2
commit 73f0d49a96
1 changed files with 39 additions and 24 deletions
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63
block/blk-throttle.c
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@ -27,6 +27,17 @@ static struct blkcg_policy blkcg_policy_throtl;
static struct workqueue_struct *kthrotld_workqueue;
struct throtl_service_queue {
/*
* Bios queued directly to this service_queue or dispatched from
* children throtl_grp's.
*/
struct bio_list bio_lists[2]; /* queued bios [READ/WRITE] */
unsigned int nr_queued[2]; /* number of queued bios */
/*
* RB tree of active children throtl_grp's, which are sorted by
* their ->disptime.
*/
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 */
@ -69,12 +80,6 @@ struct throtl_grp {
unsigned int flags;
/* Two lists for READ and WRITE */
struct bio_list bio_lists[2];
/* Number of queued bios on READ and WRITE lists */
unsigned int nr_queued[2];
/* bytes per second rate limits */
uint64_t bps[2];
@ -193,6 +198,8 @@ 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)
{
bio_list_init(&sq->bio_lists[0]);
bio_list_init(&sq->bio_lists[1]);
sq->pending_tree = RB_ROOT;
}
@ -204,8 +211,6 @@ static void throtl_pd_init(struct blkcg_gq *blkg)
throtl_service_queue_init(&tg->service_queue);
RB_CLEAR_NODE(&tg->rb_node);
tg->td = blkg->q->td;
bio_list_init(&tg->bio_lists[0]);
bio_list_init(&tg->bio_lists[1]);
tg->bps[READ] = -1;
tg->bps[WRITE] = -1;
@ -624,7 +629,8 @@ static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio,
* this function with a different bio if there are other bios
* queued.
*/
BUG_ON(tg->nr_queued[rw] && bio != bio_list_peek(&tg->bio_lists[rw]));
BUG_ON(tg->service_queue.nr_queued[rw] &&
bio != bio_list_peek(&tg->service_queue.bio_lists[rw]));
/* If tg->bps = -1, then BW is unlimited */
if (tg->bps[rw] == -1 && tg->iops[rw] == -1) {
@ -703,12 +709,13 @@ static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
static void throtl_add_bio_tg(struct bio *bio, struct throtl_grp *tg,
struct throtl_service_queue *parent_sq)
{
struct throtl_service_queue *sq = &tg->service_queue;
bool rw = bio_data_dir(bio);
bio_list_add(&tg->bio_lists[rw], bio);
bio_list_add(&sq->bio_lists[rw], bio);
/* Take a bio reference on tg */
blkg_get(tg_to_blkg(tg));
tg->nr_queued[rw]++;
sq->nr_queued[rw]++;
tg->td->nr_queued[rw]++;
throtl_enqueue_tg(tg, parent_sq);
}
@ -716,13 +723,14 @@ static void throtl_add_bio_tg(struct bio *bio, struct throtl_grp *tg,
static void tg_update_disptime(struct throtl_grp *tg,
struct throtl_service_queue *parent_sq)
{
struct throtl_service_queue *sq = &tg->service_queue;
unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime;
struct bio *bio;
if ((bio = bio_list_peek(&tg->bio_lists[READ])))
if ((bio = bio_list_peek(&sq->bio_lists[READ])))
tg_may_dispatch(tg, bio, &read_wait);
if ((bio = bio_list_peek(&tg->bio_lists[WRITE])))
if ((bio = bio_list_peek(&sq->bio_lists[WRITE])))
tg_may_dispatch(tg, bio, &write_wait);
min_wait = min(read_wait, write_wait);
@ -737,10 +745,11 @@ static void tg_update_disptime(struct throtl_grp *tg,
static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw,
struct bio_list *bl)
{
struct throtl_service_queue *sq = &tg->service_queue;
struct bio *bio;
bio = bio_list_pop(&tg->bio_lists[rw]);
tg->nr_queued[rw]--;
bio = bio_list_pop(&sq->bio_lists[rw]);
sq->nr_queued[rw]--;
/* Drop bio reference on blkg */
blkg_put(tg_to_blkg(tg));
@ -756,6 +765,7 @@ static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw,
static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl)
{
struct throtl_service_queue *sq = &tg->service_queue;
unsigned int nr_reads = 0, nr_writes = 0;
unsigned int max_nr_reads = throtl_grp_quantum*3/4;
unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads;
@ -763,7 +773,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl)
/* Try to dispatch 75% READS and 25% WRITES */
while ((bio = bio_list_peek(&tg->bio_lists[READ])) &&
while ((bio = bio_list_peek(&sq->bio_lists[READ])) &&
tg_may_dispatch(tg, bio, NULL)) {
tg_dispatch_one_bio(tg, bio_data_dir(bio), bl);
@ -773,7 +783,7 @@ static int throtl_dispatch_tg(struct throtl_grp *tg, struct bio_list *bl)
break;
}
while ((bio = bio_list_peek(&tg->bio_lists[WRITE])) &&
while ((bio = bio_list_peek(&sq->bio_lists[WRITE])) &&
tg_may_dispatch(tg, bio, NULL)) {
tg_dispatch_one_bio(tg, bio_data_dir(bio), bl);
@ -790,10 +800,10 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq,
struct bio_list *bl)
{
unsigned int nr_disp = 0;
struct throtl_grp *tg;
while (1) {
tg = throtl_rb_first(parent_sq);
struct throtl_grp *tg = throtl_rb_first(parent_sq);
struct throtl_service_queue *sq = &tg->service_queue;
if (!tg)
break;
@ -805,7 +815,7 @@ static int throtl_select_dispatch(struct throtl_service_queue *parent_sq,
nr_disp += throtl_dispatch_tg(tg, bl);
if (tg->nr_queued[0] || tg->nr_queued[1])
if (sq->nr_queued[0] || sq->nr_queued[1])
tg_update_disptime(tg, parent_sq);
if (nr_disp >= throtl_quantum)
@ -1043,6 +1053,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
{
struct throtl_data *td = q->td;
struct throtl_grp *tg;
struct throtl_service_queue *sq;
bool rw = bio_data_dir(bio), update_disptime = true;
struct blkcg *blkcg;
bool throttled = false;
@ -1077,7 +1088,9 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
if (unlikely(!tg))
goto out_unlock;
if (tg->nr_queued[rw]) {
sq = &tg->service_queue;
if (sq->nr_queued[rw]) {
/*
* There is already another bio queued in same dir. No
* need to update dispatch time.
@ -1112,7 +1125,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
rw == READ ? 'R' : 'W',
tg->bytes_disp[rw], bio->bi_size, tg->bps[rw],
tg->io_disp[rw], tg->iops[rw],
tg->nr_queued[READ], tg->nr_queued[WRITE]);
sq->nr_queued[READ], sq->nr_queued[WRITE]);
bio_associate_current(bio);
throtl_add_bio_tg(bio, tg, &q->td->service_queue);
@ -1151,11 +1164,13 @@ void blk_throtl_drain(struct request_queue *q)
bio_list_init(&bl);
while ((tg = throtl_rb_first(parent_sq))) {
struct throtl_service_queue *sq = &tg->service_queue;
throtl_dequeue_tg(tg, parent_sq);
while ((bio = bio_list_peek(&tg->bio_lists[READ])))
while ((bio = bio_list_peek(&sq->bio_lists[READ])))
tg_dispatch_one_bio(tg, bio_data_dir(bio), &bl);
while ((bio = bio_list_peek(&tg->bio_lists[WRITE])))
while ((bio = bio_list_peek(&sq->bio_lists[WRITE])))
tg_dispatch_one_bio(tg, bio_data_dir(bio), &bl);
}
spin_unlock_irq(q->queue_lock);