diff options
| author | Ming Lei <ming.lei@redhat.com> | 2019-10-25 14:58:55 +0800 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2019-11-01 20:12:50 -0400 |
| commit | 6eb045e092efefafc6687409a6fa6d1dabf0fb69 (patch) | |
| tree | aeb333b78b8514f84daa88f6e431ea69ab51b22c /drivers/scsi/scsi_priv.h | |
| parent | 7f674c38a38e056bb33d1d67700410c3f3124d34 (diff) | |
scsi: core: avoid host-wide host_busy counter for scsi_mq
It isn't necessary to check the host depth in scsi_queue_rq() any more
since it has been respected by blk-mq before calling scsi_queue_rq() via
getting driver tag.
Lots of LUNs may attach to same host and per-host IOPS may reach millions,
so we should avoid expensive atomic operations on the host-wide counter in
the IO path.
This patch implements scsi_host_busy() via blk_mq_tagset_busy_iter() with
one scsi command state for reading the count of busy IOs for scsi_mq.
It is observed that IOPS is increased by 15% in IO test on scsi_debug (32
LUNs, 32 submit queues, 1024 can_queue, libaio/dio) in a dual-socket
system.
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Omar Sandoval <osandov@fb.com>,
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
Cc: James Bottomley <james.bottomley@hansenpartnership.com>,
Cc: Christoph Hellwig <hch@lst.de>,
Cc: Kashyap Desai <kashyap.desai@broadcom.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Laurence Oberman <loberman@redhat.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20191025065855.6309-1-ming.lei@redhat.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/scsi_priv.h')
| -rw-r--r-- | drivers/scsi/scsi_priv.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h index cc2859d76d81..3bff9f7aa684 100644 --- a/drivers/scsi/scsi_priv.h +++ b/drivers/scsi/scsi_priv.h @@ -87,7 +87,7 @@ int scsi_noretry_cmd(struct scsi_cmnd *scmd); extern void scsi_add_cmd_to_list(struct scsi_cmnd *cmd); extern void scsi_del_cmd_from_list(struct scsi_cmnd *cmd); extern int scsi_maybe_unblock_host(struct scsi_device *sdev); -extern void scsi_device_unbusy(struct scsi_device *sdev); +extern void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd); extern void scsi_queue_insert(struct scsi_cmnd *cmd, int reason); extern void scsi_io_completion(struct scsi_cmnd *, unsigned int); extern void scsi_run_host_queues(struct Scsi_Host *shost); |