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block: fix plug list flushing for nomerge queues

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Request queues with merging disabled will not flush the plug list after
BLK_MAX_REQUEST_COUNT requests have been queued, since the code relies
on blk_attempt_plug_merge to compute the request_count.  Fix this by
computing the number of queued requests even for nomerge queues.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Jeff Moyer 2015-10-20 23:13:51 +08:00 committed by Jens Axboe
parent 3380f4589f
commit 0809e3ac62
3 changed files with 36 additions and 6 deletions
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32
block/blk-core.c
View File

@ -1594,6 +1594,30 @@ out:
return ret;
}
unsigned int blk_plug_queued_count(struct request_queue *q)
{
struct blk_plug *plug;
struct request *rq;
struct list_head *plug_list;
unsigned int ret = 0;
plug = current->plug;
if (!plug)
goto out;
if (q->mq_ops)
plug_list = &plug->mq_list;
else
plug_list = &plug->list;
list_for_each_entry(rq, plug_list, queuelist) {
if (rq->q == q)
ret++;
}
out:
return ret;
}
void init_request_from_bio(struct request *req, struct bio *bio)
{
req->cmd_type = REQ_TYPE_FS;
@ -1641,9 +1665,11 @@ static void blk_queue_bio(struct request_queue *q, struct bio *bio)
* Check if we can merge with the plugged list before grabbing
* any locks.
*/
if (!blk_queue_nomerges(q) &&
blk_attempt_plug_merge(q, bio, &request_count, NULL))
return;
if (!blk_queue_nomerges(q)) {
if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
return;
} else
request_count = blk_plug_queued_count(q);
spin_lock_irq(q->queue_lock);

9
block/blk-mq.c
View File

@ -1268,9 +1268,12 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
blk_queue_split(q, &bio, q->bio_split);
if (!is_flush_fua && !blk_queue_nomerges(q) &&
blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
return;
if (!is_flush_fua && !blk_queue_nomerges(q)) {
if (blk_attempt_plug_merge(q, bio, &request_count,
&same_queue_rq))
return;
} else
request_count = blk_plug_queued_count(q);
rq = blk_mq_map_request(q, bio, &data);
if (unlikely(!rq))

1
block/blk.h
View File

@ -86,6 +86,7 @@ bool bio_attempt_back_merge(struct request_queue *q, struct request *req,
bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio,
unsigned int *request_count,
struct request **same_queue_rq);
unsigned int blk_plug_queued_count(struct request_queue *q);
void blk_account_io_start(struct request *req, bool new_io);
void blk_account_io_completion(struct request *req, unsigned int bytes);