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6eb045e092
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> |
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| .. | ||
| fc | ||
| fc_encode.h | ||
| fc_frame.h | ||
| fcoe_sysfs.h | ||
| iscsi_if.h | ||
| iscsi_proto.h | ||
| iser.h | ||
| libfc.h | ||
| libfcoe.h | ||
| libiscsi.h | ||
| libiscsi_tcp.h | ||
| libsas.h | ||
| sas.h | ||
| sas_ata.h | ||
| scsi.h | ||
| scsi_bsg_iscsi.h | ||
| scsi_cmnd.h | ||
| scsi_common.h | ||
| scsi_dbg.h | ||
| scsi_device.h | ||
| scsi_devinfo.h | ||
| scsi_dh.h | ||
| scsi_driver.h | ||
| scsi_eh.h | ||
| scsi_host.h | ||
| scsi_ioctl.h | ||
| scsi_proto.h | ||
| scsi_request.h | ||
| scsi_tcq.h | ||
| scsi_transport.h | ||
| scsi_transport_fc.h | ||
| scsi_transport_iscsi.h | ||
| scsi_transport_sas.h | ||
| scsi_transport_spi.h | ||
| scsi_transport_srp.h | ||
| scsicam.h | ||
| sg.h | ||
| srp.h | ||
| viosrp.h | ||