From 77216b0484817817a18aaa6b089dffe49070f7c1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 14 May 2013 13:52:36 -0700 Subject: blk-throttle: add throtl_service_queue->parent_sq 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 Acked-by: Vivek Goyal --- block/blk-throttle.c | 81 +++++++++++++++++++++++++--------------------------- 1 file changed, 39 insertions(+), 42 deletions(-) (limited to 'block/blk-throttle.c') diff --git a/block/blk-throttle.c b/block/blk-throttle.c index ec9397f3eb0ac..00cfdd05f98f9 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); } @@ -1142,12 +1139,12 @@ 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); } @@ -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; -- cgit v1.2.3