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block: wake up waiters when a queue is marked dying

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If it's dying, we can't expect new request to complete and come
in an wake up other tasks waiting for requests. So after we
have marked it as dying, wake up everybody currently waiting
for a request. Once they wake, they will retry their allocation
and fail appropriately due to the state of the queue.

Tested-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jens Axboe 2014-12-22 14:04:42 -07:00
parent 2b25d98179
commit aed3ea94bd
5 changed files with 42 additions and 5 deletions
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21
block/blk-core.c
View file

@ -473,6 +473,25 @@ void blk_queue_bypass_end(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
void blk_set_queue_dying(struct request_queue *q)
{
queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
if (q->mq_ops)
blk_mq_wake_waiters(q);
else {
struct request_list *rl;
blk_queue_for_each_rl(rl, q) {
if (rl->rq_pool) {
wake_up(&rl->wait[BLK_RW_SYNC]);
wake_up(&rl->wait[BLK_RW_ASYNC]);
}
}
}
}
EXPORT_SYMBOL_GPL(blk_set_queue_dying);
/**
* blk_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
@ -486,7 +505,7 @@ void blk_cleanup_queue(struct request_queue *q)
/* mark @q DYING, no new request or merges will be allowed afterwards */
mutex_lock(&q->sysfs_lock);
queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
blk_set_queue_dying(q);
spin_lock_irq(lock);
/*

14
block/blk-mq-tag.c
View file

@ -68,9 +68,9 @@ bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
}
/*
* Wakeup all potentially sleeping on normal (non-reserved) tags
* Wakeup all potentially sleeping on tags
*/
static void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags)
void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
{
struct blk_mq_bitmap_tags *bt;
int i, wake_index;
@ -85,6 +85,12 @@ static void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags)
wake_index = bt_index_inc(wake_index);
}
if (include_reserve) {
bt = &tags->breserved_tags;
if (waitqueue_active(&bt->bs[0].wait))
wake_up(&bt->bs[0].wait);
}
}
/*
@ -100,7 +106,7 @@ void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
atomic_dec(&tags->active_queues);
blk_mq_tag_wakeup_all(tags);
blk_mq_tag_wakeup_all(tags, false);
}
/*
@ -584,7 +590,7 @@ int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int tdepth)
* static and should never need resizing.
*/
bt_update_count(&tags->bitmap_tags, tdepth);
blk_mq_tag_wakeup_all(tags);
blk_mq_tag_wakeup_all(tags, false);
return 0;
}

1
block/blk-mq-tag.h
View file

@ -54,6 +54,7 @@ extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);
extern void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *last_tag);
extern int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int depth);
extern void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool);
enum {
BLK_MQ_TAG_CACHE_MIN = 1,

10
block/blk-mq.c
View file

@ -152,6 +152,16 @@ void blk_mq_unfreeze_queue(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
void blk_mq_wake_waiters(struct request_queue *q)
{
struct blk_mq_hw_ctx *hctx;
unsigned int i;
queue_for_each_hw_ctx(q, hctx, i)
if (blk_mq_hw_queue_mapped(hctx))
blk_mq_tag_wakeup_all(hctx->tags, true);
}
bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
{
return blk_mq_has_free_tags(hctx->tags);

1
block/blk-mq.h
View file

@ -32,6 +32,7 @@ void blk_mq_free_queue(struct request_queue *q);
void blk_mq_clone_flush_request(struct request *flush_rq,
struct request *orig_rq);
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr);
void blk_mq_wake_waiters(struct request_queue *q);
/*
* CPU hotplug helpers