linux/include/scsi
Jens Axboe 9937a5e2f3 scsi: remove performance regression due to async queue run
Commit c21e6beb removed our queue request_fn re-enter
protection, and defaulted to always running the queues from
kblockd to be safe. This was a known potential slow down,
but should be safe.

Unfortunately this is causing big performance regressions for
some, so we need to improve this logic. Looking into the details
of the re-enter, the real issue is on requeue of requests.

Requeue of requests upon seeing a BUSY condition from the device
ends up re-running the queue, causing traces like this:

scsi_request_fn()
        scsi_dispatch_cmd()
                scsi_queue_insert()
                        __scsi_queue_insert()
                                scsi_run_queue()
					scsi_request_fn()
						...

potentially causing the issue we want to avoid. So special
case the requeue re-run of the queue, but improve it to offload
the entire run of local queue and starved queue from a single
workqueue callback. This is a lot better than potentially
kicking off a workqueue run for each device seen.

This also fixes the issue of the local device going into recursion,
since the above mentioned commit never moved that queue run out
of line.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-17 11:04:44 +02:00
..
fc Fix common misspellings 2011-03-31 11:26:23 -03:00
fc_encode.h [SCSI] libfc: introduce __fc_fill_fc_hdr that accepts fc_hdr as an argument 2011-02-28 18:32:33 -06:00
fc_frame.h [SCSI] libfc: add fc_frame_sid() and fc_frame_did() functions 2010-07-28 09:05:59 -05:00
iscsi_if.h Fix common misspellings 2011-03-31 11:26:23 -03:00
iscsi_proto.h [SCSI] libiscsi: Check TMF state before sending PDU 2009-12-04 12:01:36 -06:00
Kbuild [SCSI] Unexport scsi/scsi.h from headers_install 2010-05-02 11:45:12 -04:00
libfc.h Fix common misspellings 2011-03-31 11:26:23 -03:00
libfcoe.h [SCSI] libfcoe: Move FCOE_MTU definition from fcoe.h to libfcoe.h 2011-02-28 18:33:12 -06:00
libiscsi.h [SCSI] cxgbi: convert to use iscsi_conn_get_addr_param 2011-02-24 12:41:15 -05:00
libiscsi_tcp.h Fix common misspellings 2011-03-31 11:26:23 -03:00
libsas.h [SCSI] libsas: fix definition of wideport, include local sas address 2010-12-21 12:23:53 -06:00
libsrp.h libsrp: fix compile failure 2009-12-30 12:23:27 -08:00
osd_attributes.h [SCSI] libosd: OSD2r05: Attribute definitions 2009-06-10 08:54:07 -05:00
osd_initiator.h Fix common misspellings 2011-03-31 11:26:23 -03:00
osd_protocol.h [SCSI] libosd: Support for scatter gather write/read commands 2010-10-26 10:42:34 -05:00
osd_sec.h [SCSI] libosd: OSDv1 Headers 2009-03-12 12:58:06 -05:00
osd_sense.h [SCSI] libosd: osd_sense: OSD_CFO_PERMISSIONS 2009-12-04 12:01:44 -06:00
osd_types.h [SCSI] libosd: Support for scatter gather write/read commands 2010-10-26 10:42:34 -05:00
sas.h
sas_ata.h libsas: convert to libata new error handler 2011-03-02 02:36:45 -05:00
scsi.h Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6 2011-03-17 17:54:40 -07:00
scsi_bsg_fc.h [SCSI] fc-transport: Use packed modifier for fc_bsg_request structure. 2010-01-17 12:36:33 -06:00
scsi_cmnd.h [SCSI] Deprecate SCSI_PROT_*_CONVERT operations 2009-10-02 09:46:25 -05:00
scsi_dbg.h
scsi_device.h scsi: remove performance regression due to async queue run 2011-05-17 11:04:44 +02:00
scsi_devinfo.h
scsi_dh.h [SCSI] scsi_dh: Change the scsidh_activate interface to be asynchronous 2009-12-04 12:00:46 -06:00
scsi_driver.h sd, sr: fix Driver 'sd' needs updating message 2009-06-21 12:01:27 -05:00
scsi_eh.h [SCSI] scsi_eh_prep_cmnd should save scmd->underflow 2008-07-26 15:14:56 -04:00
scsi_host.h Fix common misspellings 2011-03-31 11:26:23 -03:00
scsi_ioctl.h [PATCH] don't mess with file in scsi_nonblockable_ioctl() 2008-10-21 07:47:28 -04:00
scsi_netlink.h scsi: use __uX types for headers exported to user space 2010-08-11 08:59:01 -07:00
scsi_netlink_fc.h
scsi_scan.h PM/Hibernate: Wait for SCSI devices scan to complete during resume 2009-04-13 11:37:07 -07:00
scsi_tcq.h block: remove spurious uses of REQ_HARDBARRIER 2010-09-10 12:35:36 +02:00
scsi_tgt.h
scsi_tgt_if.h
scsi_transport.h block: unify request timeout handling 2008-10-09 08:56:13 +02:00
scsi_transport_fc.h Fix common misspellings 2011-03-31 11:26:23 -03:00
scsi_transport_iscsi.h [SCSI] iscsi class: add callout to get iscsi_endpoint values 2011-02-24 12:41:12 -05:00
scsi_transport_sas.h [SCSI] scsi_transport_sas: add support for transport layer retries (TLR) 2010-02-08 17:15:19 -06:00
scsi_transport_spi.h [SCSI] aic79xx: make driver respect nvram for IU and QAS settings 2009-06-15 10:09:35 -05:00
scsi_transport_srp.h
scsicam.h
sg.h sysctl extern cleanup: sg 2010-03-12 15:53:10 -08:00
srp.h IB/srp: Implement SRP_CRED_REQ and SRP_AER_REQ 2010-10-22 22:19:10 -07:00