linux/include/scsi
Ming Lei 6eb045e092 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>
2019-11-01 20:12:50 -04:00
..
fc SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
fc_encode.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
fc_frame.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
fcoe_sysfs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
iscsi_if.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
iscsi_proto.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
iser.h IB/iser,isert: Create and use new shared header 2015-12-24 00:17:35 -05:00
libfc.h scsi: libfc: Whitespace cleanup in libfc.h 2019-07-29 20:43:06 -04:00
libfcoe.h scsi: fcoe: Embed fc_rport_priv in fcoe_rport structure 2019-07-29 21:12:35 -04:00
libiscsi_tcp.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
libiscsi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
libsas.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
sas_ata.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
sas.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
scsi_bsg_iscsi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
scsi_cmnd.h scsi: core: avoid host-wide host_busy counter for scsi_mq 2019-11-01 20:12:50 -04:00
scsi_common.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
scsi_dbg.h scsi: core: Reduce memory required for SCSI logging 2019-08-07 21:47:29 -04:00
scsi_device.h scsi: core: Add sysfs attributes for VPD pages 0h and 89h 2019-09-30 23:24:36 -04:00
scsi_devinfo.h scsi: devinfo: BLIST_RETRY_ASC_C1 for Fujitsu ETERNUS 2018-04-20 19:14:36 -04:00
scsi_dh.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
scsi_driver.h scsi: return blk_status_t from scsi_init_io and ->init_command 2018-11-09 19:17:14 -07:00
scsi_eh.h scsi: core: save/restore command resid for error handling 2019-10-03 21:43:04 -04:00
scsi_host.h scsi: core: avoid host-wide host_busy counter for scsi_mq 2019-11-01 20:12:50 -04:00
scsi_ioctl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
scsi_proto.h scsi: core: Add VENDOR_SPECIFIC sense code definitions 2018-01-22 20:04:02 -05:00
scsi_request.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
scsi_tcq.h scsi: kill off the legacy IO path 2018-11-07 13:42:32 -07:00
scsi_transport_fc.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
scsi_transport_iscsi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
scsi_transport_sas.h scsi: libsas: direct call probe and destruct 2018-01-10 23:24:02 -05:00
scsi_transport_spi.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
scsi_transport_srp.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
scsi_transport.h SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
scsi.h scsi: libsas: Remove scsi_to_u32() 2019-01-29 00:46:22 -05:00
scsicam.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sg.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
srp.h include/scsi/srp.h: Add support for immediate data 2018-12-19 15:07:25 -05:00
viosrp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00