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scsi: implement .get_budget and .put_budget for blk-mq
We need to tell blk-mq to reserve resources before queuing one request, so implement these two callbacks. Then blk-mq can avoid to dequeue request too early, and IO merging can be improved a lot. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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aeec77629a
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0df21c86bd
1 changed files with 52 additions and 23 deletions
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@ -1946,25 +1946,32 @@ static void scsi_mq_done(struct scsi_cmnd *cmd)
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blk_mq_complete_request(cmd->request);
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}
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static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
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const struct blk_mq_queue_data *bd)
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static void scsi_mq_put_budget(struct blk_mq_hw_ctx *hctx)
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{
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struct request *req = bd->rq;
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struct request_queue *q = req->q;
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struct request_queue *q = hctx->queue;
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struct scsi_device *sdev = q->queuedata;
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struct Scsi_Host *shost = sdev->host;
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atomic_dec(&shost->host_busy);
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if (scsi_target(sdev)->can_queue > 0)
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atomic_dec(&scsi_target(sdev)->target_busy);
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atomic_dec(&sdev->device_busy);
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put_device(&sdev->sdev_gendev);
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}
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static blk_status_t scsi_mq_get_budget(struct blk_mq_hw_ctx *hctx)
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{
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struct request_queue *q = hctx->queue;
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struct scsi_device *sdev = q->queuedata;
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struct Scsi_Host *shost = sdev->host;
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struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
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blk_status_t ret;
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int reason;
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ret = prep_to_mq(scsi_prep_state_check(sdev, req));
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if (ret != BLK_STS_OK)
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goto out;
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ret = prep_to_mq(scsi_prep_state_check(sdev, NULL));
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if (ret == BLK_STS_RESOURCE || ret != BLK_STS_OK)
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return ret;
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ret = BLK_STS_RESOURCE;
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if (!get_device(&sdev->sdev_gendev))
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goto out;
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if (!scsi_dev_queue_ready(q, sdev))
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goto out_put_device;
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if (!scsi_target_queue_ready(shost, sdev))
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@ -1972,10 +1979,38 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
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if (!scsi_host_queue_ready(q, shost, sdev))
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goto out_dec_target_busy;
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return BLK_STS_OK;
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out_dec_target_busy:
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if (scsi_target(sdev)->can_queue > 0)
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atomic_dec(&scsi_target(sdev)->target_busy);
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out_dec_device_busy:
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atomic_dec(&sdev->device_busy);
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out_put_device:
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put_device(&sdev->sdev_gendev);
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out:
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return BLK_STS_RESOURCE;
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}
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static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
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const struct blk_mq_queue_data *bd)
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{
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struct request *req = bd->rq;
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struct request_queue *q = req->q;
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struct scsi_device *sdev = q->queuedata;
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struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
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blk_status_t ret;
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int reason;
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ret = prep_to_mq(scsi_prep_state_check(sdev, req));
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if (ret != BLK_STS_OK)
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goto out_put_budget;
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ret = BLK_STS_RESOURCE;
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if (!(req->rq_flags & RQF_DONTPREP)) {
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ret = prep_to_mq(scsi_mq_prep_fn(req));
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if (ret != BLK_STS_OK)
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goto out_dec_host_busy;
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goto out_put_budget;
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req->rq_flags |= RQF_DONTPREP;
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} else {
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blk_mq_start_request(req);
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@ -1993,21 +2028,13 @@ static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
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if (reason) {
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scsi_set_blocked(cmd, reason);
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ret = BLK_STS_RESOURCE;
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goto out_dec_host_busy;
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goto out_put_budget;
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}
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return BLK_STS_OK;
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out_dec_host_busy:
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atomic_dec(&shost->host_busy);
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out_dec_target_busy:
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if (scsi_target(sdev)->can_queue > 0)
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atomic_dec(&scsi_target(sdev)->target_busy);
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out_dec_device_busy:
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atomic_dec(&sdev->device_busy);
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out_put_device:
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put_device(&sdev->sdev_gendev);
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out:
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out_put_budget:
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scsi_mq_put_budget(hctx);
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switch (ret) {
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case BLK_STS_OK:
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break;
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@ -2211,6 +2238,8 @@ struct request_queue *scsi_old_alloc_queue(struct scsi_device *sdev)
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}
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static const struct blk_mq_ops scsi_mq_ops = {
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.get_budget = scsi_mq_get_budget,
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.put_budget = scsi_mq_put_budget,
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.queue_rq = scsi_queue_rq,
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.complete = scsi_softirq_done,
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.timeout = scsi_timeout,
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