block: skip elevator data initialization for flush requests
Skip elevator initialization for flush requests by passing priv=0 to blk_alloc_request() in get_request(). As such elv_set_request() is never called for flush requests. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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ae1b153962
Коммит
9d5a4e946c
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@ -737,6 +737,25 @@ static void freed_request(struct request_queue *q, int sync, int priv)
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__freed_request(q, sync ^ 1);
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__freed_request(q, sync ^ 1);
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}
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}
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/*
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* Determine if elevator data should be initialized when allocating the
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* request associated with @bio.
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*/
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static bool blk_rq_should_init_elevator(struct bio *bio)
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{
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if (!bio)
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return true;
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/*
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* Flush requests do not use the elevator so skip initialization.
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* This allows a request to share the flush and elevator data.
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*/
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if (bio->bi_rw & (REQ_FLUSH | REQ_FUA))
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return false;
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return true;
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}
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/*
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/*
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* Get a free request, queue_lock must be held.
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* Get a free request, queue_lock must be held.
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* Returns NULL on failure, with queue_lock held.
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* Returns NULL on failure, with queue_lock held.
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@ -749,7 +768,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
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struct request_list *rl = &q->rq;
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struct request_list *rl = &q->rq;
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struct io_context *ioc = NULL;
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struct io_context *ioc = NULL;
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const bool is_sync = rw_is_sync(rw_flags) != 0;
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const bool is_sync = rw_is_sync(rw_flags) != 0;
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int may_queue, priv;
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int may_queue, priv = 0;
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may_queue = elv_may_queue(q, rw_flags);
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may_queue = elv_may_queue(q, rw_flags);
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if (may_queue == ELV_MQUEUE_NO)
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if (may_queue == ELV_MQUEUE_NO)
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@ -793,9 +812,11 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
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rl->count[is_sync]++;
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rl->count[is_sync]++;
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rl->starved[is_sync] = 0;
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rl->starved[is_sync] = 0;
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if (blk_rq_should_init_elevator(bio)) {
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priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
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priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
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if (priv)
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if (priv)
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rl->elvpriv++;
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rl->elvpriv++;
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}
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if (blk_queue_io_stat(q))
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if (blk_queue_io_stat(q))
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rw_flags |= REQ_IO_STAT;
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rw_flags |= REQ_IO_STAT;
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