Re: [PATCH 0/5] scsi: Allow fast io fail without waiting throughtimeout

From: Ren Mingxin
Date: Wed May 22 2013 - 03:09:39 EST

Hi, James,

On 05/20/2013 11:53 PM, James Smart wrote:
Based on the discussion recently held at LSF 2013, we are
reworking the error recovery path to address all the issues
you are mentioning. That work contradicts these patches.
So for now, these should be held off.

Interesting. Can I have your general goal/idea briefly even
though via a reference? Will the URL below be one you will
refer to?

And, could I know your current progress/schedule? Especially
when can we see your patches?

Much appreciated!


On 5/20/2013 3:14 AM, Ren Mingxin wrote:
When there is a scsi command timed-out or failed, the scsi eh
tries a thorugh recovery, which is necessary for non-redundant
systems. However, the thorugh recovery usually takes much time,
which is not acceptable for misson critical systems. To improve
this latency, if we are working on a redundant system, we should
avoid the scsi eh for its long time failing recovery, and quick
failover to another path.

This set of patches is trying to implement above.

NOTE: the userland tools need to eusure the environment
restriction, which will be implemented later.


Ren Mingxin (5):
scsi: rename return code FAST_IO_FAIL to FAST_IO
FC transport: Add interface to specify fast io level for timed-out cmds
SAS transport: Add interface to specify fast io level for timed-out cmds
lpfc: Allow fast timed-out io recovery
mptfusion: Allow fast timed-out io recovery

drivers/message/fusion/mptscsih.c | 29 ++++++++-
drivers/scsi/lpfc/lpfc_scsi.c | 34 ++++++++++
drivers/scsi/scsi_error.c | 18 ++---
drivers/scsi/scsi_sas_internal.h | 4 -
drivers/scsi/scsi_transport_fc.c | 112 ++++++++++++++++++++++++++++++++++--
drivers/scsi/scsi_transport_iscsi.c | 6 -
drivers/scsi/scsi_transport_sas.c | 103 ++++++++++++++++++++++++++++++++-
include/scsi/scsi.h | 2
include/scsi/scsi_transport_fc.h | 11 +++
include/scsi/scsi_transport_sas.h | 8 ++
10 files changed, 303 insertions(+), 24 deletions(-)
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