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blk-mq: add timer in blk_mq_start_request
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This way will become consistent with non-mq case, also
avoid to update rq->deadline twice for mq.

The comment said: "We do this early, to ensure we are on
the right CPU.", but no percpu stuff is used in blk_add_timer(),
so it isn't necessary. Even when inserting from plug list, there
is no such guarantee at all.

Signed-off-by: Ming Lei <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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ming1 authored and axboe committed Jun 9, 2014
1 parent 3ee3237 commit 2b8393b
Showing 1 changed file with 1 addition and 16 deletions.
17 changes: 1 addition & 16 deletions block/blk-mq.c
Original file line number Diff line number Diff line change
Expand Up @@ -411,16 +411,7 @@ static void blk_mq_start_request(struct request *rq, bool last)
if (unlikely(blk_bidi_rq(rq)))
rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq);

/*
* Just mark start time and set the started bit. Due to memory
* ordering, we know we'll see the correct deadline as long as
* REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
* unless one has been set in the request.
*/
if (!rq->timeout)
rq->deadline = jiffies + q->rq_timeout;
else
rq->deadline = jiffies + rq->timeout;
blk_add_timer(rq);

/*
* Mark us as started and clear complete. Complete might have been
Expand Down Expand Up @@ -972,11 +963,6 @@ static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
list_add_tail(&rq->queuelist, &ctx->rq_list);

blk_mq_hctx_mark_pending(hctx, ctx);

/*
* We do this early, to ensure we are on the right CPU.
*/
blk_add_timer(rq);
}

void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
Expand Down Expand Up @@ -1219,7 +1205,6 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)

blk_mq_bio_to_request(rq, bio);
blk_mq_start_request(rq, true);
blk_add_timer(rq);

/*
* For OK queue, we are done. For error, kill it. Any other
Expand Down

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