diff options
Diffstat (limited to 'block/blk-throttle.c')
| -rw-r--r-- | block/blk-throttle.c | 106 |
1 files changed, 62 insertions, 44 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index a19f58c..4553245 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -10,6 +10,7 @@ #include <linux/bio.h> #include <linux/blktrace_api.h> #include "blk-cgroup.h" +#include "blk.h" /* Max dispatch from a group in 1 round */ static int throtl_grp_quantum = 8; @@ -302,16 +303,16 @@ throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg) return tg; } -/* - * This function returns with queue lock unlocked in case of error, like - * request queue is no more - */ static struct throtl_grp * throtl_get_tg(struct throtl_data *td) { struct throtl_grp *tg = NULL, *__tg = NULL; struct blkio_cgroup *blkcg; struct request_queue *q = td->queue; + /* no throttling for dead queue */ + if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) + return NULL; + rcu_read_lock(); blkcg = task_blkio_cgroup(current); tg = throtl_find_tg(td, blkcg); @@ -323,32 +324,22 @@ static struct throtl_grp * throtl_get_tg(struct throtl_data *td) /* * Need to allocate a group. Allocation of group also needs allocation * of per cpu stats which in-turn takes a mutex() and can block. Hence - * we need to drop rcu lock and queue_lock before we call alloc - * - * Take the request queue reference to make sure queue does not - * go away once we return from allocation. + * we need to drop rcu lock and queue_lock before we call alloc. */ - blk_get_queue(q); rcu_read_unlock(); spin_unlock_irq(q->queue_lock); tg = throtl_alloc_tg(td); - /* - * We might have slept in group allocation. Make sure queue is not - * dead - */ - if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { - blk_put_queue(q); - if (tg) - kfree(tg); - - return ERR_PTR(-ENODEV); - } - blk_put_queue(q); /* Group allocated and queue is still alive. take the lock */ spin_lock_irq(q->queue_lock); + /* Make sure @q is still alive */ + if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) { + kfree(tg); + return NULL; + } + /* * Initialize the new group. After sleeping, read the blkcg again. */ @@ -1014,11 +1005,6 @@ static void throtl_release_tgs(struct throtl_data *td) } } -static void throtl_td_free(struct throtl_data *td) -{ - kfree(td); -} - /* * Blk cgroup controller notification saying that blkio_group object is being * delinked as associated cgroup object is going away. That also means that @@ -1123,17 +1109,17 @@ static struct blkio_policy_type blkio_policy_throtl = { .plid = BLKIO_POLICY_THROTL, }; -int blk_throtl_bio(struct request_queue *q, struct bio **biop) +bool blk_throtl_bio(struct request_queue *q, struct bio *bio) { struct throtl_data *td = q->td; struct throtl_grp *tg; - struct bio *bio = *biop; bool rw = bio_data_dir(bio), update_disptime = true; struct blkio_cgroup *blkcg; + bool throttled = false; if (bio->bi_rw & REQ_THROTTLED) { bio->bi_rw &= ~REQ_THROTTLED; - return 0; + goto out; } /* @@ -1152,7 +1138,7 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop) blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, rw_is_sync(bio->bi_rw)); rcu_read_unlock(); - return 0; + goto out; } } rcu_read_unlock(); @@ -1161,18 +1147,10 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop) * Either group has not been allocated yet or it is not an unlimited * IO group */ - spin_lock_irq(q->queue_lock); tg = throtl_get_tg(td); - - if (IS_ERR(tg)) { - if (PTR_ERR(tg) == -ENODEV) { - /* - * Queue is gone. No queue lock held here. - */ - return -ENODEV; - } - } + if (unlikely(!tg)) + goto out_unlock; if (tg->nr_queued[rw]) { /* @@ -1200,7 +1178,7 @@ int blk_throtl_bio(struct request_queue *q, struct bio **biop) * So keep on trimming slice even if bio is not queued. */ throtl_trim_slice(td, tg, rw); - goto out; + goto out_unlock; } queue_bio: @@ -1212,16 +1190,52 @@ queue_bio: tg->nr_queued[READ], tg->nr_queued[WRITE]); throtl_add_bio_tg(q->td, tg, bio); - *biop = NULL; + throttled = true; if (update_disptime) { tg_update_disptime(td, tg); throtl_schedule_next_dispatch(td); } +out_unlock: + spin_unlock_irq(q->queue_lock); out: + return throttled; +} + +/** + * blk_throtl_drain - drain throttled bios + * @q: request_queue to drain throttled bios for + * + * Dispatch all currently throttled bios on @q through ->make_request_fn(). + */ +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_grp *tg; + struct bio_list bl; + struct bio *bio; + + WARN_ON_ONCE(!queue_is_locked(q)); + + bio_list_init(&bl); + + while ((tg = throtl_rb_first(st))) { + throtl_dequeue_tg(td, tg); + + while ((bio = bio_list_peek(&tg->bio_lists[READ]))) + tg_dispatch_one_bio(td, tg, bio_data_dir(bio), &bl); + while ((bio = bio_list_peek(&tg->bio_lists[WRITE]))) + tg_dispatch_one_bio(td, tg, bio_data_dir(bio), &bl); + } spin_unlock_irq(q->queue_lock); - return 0; + + while ((bio = bio_list_pop(&bl))) + generic_make_request(bio); + + spin_lock_irq(q->queue_lock); } int blk_throtl_init(struct request_queue *q) @@ -1296,7 +1310,11 @@ void blk_throtl_exit(struct request_queue *q) * it. */ throtl_shutdown_wq(q); - throtl_td_free(td); +} + +void blk_throtl_release(struct request_queue *q) +{ + kfree(q->td); } static int __init throtl_init(void) |