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

[Ren Mingxin]

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?
  http://lwn.net/Articles/548500

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

Much appreciated!

Thanks,
Ren

> 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.
> >
> > Thanks,
> > Ren
> >
> > 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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