From: KY Srinivasan <kys@microsoft.com>
To: Eric Seppanen <eric@purestorage.com>,
        "Nicholas A. Bellinger" <nab@linux-iscsi.org>
CC: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: RE: Drivers: scsi: FLUSH timeout
Thread-Topic: Drivers: scsi: FLUSH timeout
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Date: Fri, 4 Oct 2013 15:02:18 +0000
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> -----Original Message-----
> From: Eric Seppanen [mailto:eric@purestorage.com]
> Sent: Thursday, October 03, 2013 1:49 PM
> To: Nicholas A. Bellinger
> Cc: KY Srinivasan; linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> linux-scsi@vger.kernel.org
> Subject: Re: Drivers: scsi: FLUSH timeout
> 
> On Thu, Oct 3, 2013 at 5:09 AM, Nicholas A. Bellinger
> <nab@linux-iscsi.org> wrote:
> >
> > On Wed, 2013-10-02 at 18:29 +0000, KY Srinivasan wrote:
> > > Ideally, I want this to be adjustable like the way we can change the I/O
> timeout.
> > > Since that has been attempted earlier and rejected (not clear what the
> reasons were),
> > > I was suggesting that we pick a larger number. James, let me know how I
> should proceed here.
> > >
> >
> > I think the objection was to making a module parameter for doing this
> > globally for all struct scsi_disk, and not the idea of making it
> > adjustable on an individual basis per-say..
> >
> > What about adding a /sys/class/scsi_disk/$HCTL/flush_timeout..?
> 
> Do I/O timeouts and flush timeouts need to be independently adjusted?
> If you're having trouble with slow operations, it seems likely to be
> across the board.
> 
> Flush timeout could be defined as 2x the read/write timeout.  Any
> other command-specific timeouts could be scaled the same way.

I like this idea and would result in minimal changes. James, if it ok with you,
I could send you the patch.

Regards,

K. Y
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