From: Mike Christie <michaelc@cs.wisc.edu>
To: device-mapper development <dm-devel@redhat.com>
Cc: Bernd Schubert <bernd.schubert@itwm.fraunhofer.de>,
James Bottomley <James.Bottomley@HansenPartnership.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [dm-devel] multipath_busy() stalls IO due to scsi_host_is_busy()
Date: Wed, 16 May 2012 10:27:27 -0500 [thread overview]
Message-ID: <4FB3C75F.3070903@cs.wisc.edu> (raw)
In-Reply-To: <4FB3B9DE.1050903@itwm.fraunhofer.de>
On 05/16/2012 09:29 AM, Bernd Schubert wrote:
> On 05/16/2012 04:06 PM, James Bottomley wrote:
>> On Wed, 2012-05-16 at 14:28 +0200, Bernd Schubert wrote:
>>> shost->can_queue -> 62 here
>>> shost->host_busy -> 62 when one of the multipath groups does IO,
>>> further
>>> multipath groups then seem to get stalled.
>>>
>>> I'm not sure yet why multipath_busy() does not stall IO when there is a
>>> passive path in the prio group.
>>>
>>> Any idea how to properly address this problem?
>>
>> shost->can_queue is supposed to represent the maximum number of possible
>> outstanding commands per HBA (i.e. the HBA hardware limit). Assuming
>> the driver got it right, the only way of increasing this is to buy a
>> better HBA.
>
> HBA is a mellanox IB adapter. I have not checked yet where the limit of
What driver is this with? SRP or iSER or something else?
next prev parent reply other threads:[~2012-05-16 15:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-16 12:28 multipath_busy() stalls IO due to scsi_host_is_busy() Bernd Schubert
2012-05-16 14:06 ` James Bottomley
2012-05-16 14:29 ` Bernd Schubert
2012-05-16 15:27 ` Mike Christie [this message]
[not found] ` <4FB3C75F.3070903-hcNo3dDEHLuVc3sceRu5cw@public.gmane.org>
2012-05-16 15:54 ` [dm-devel] " Bernd Schubert
[not found] ` <4FB3CDC5.9040608-mPn0NPGs4xGatNDF+KUbs4QuADTiUCJX@public.gmane.org>
2012-05-16 17:03 ` David Dillow
2012-05-16 20:34 ` Bernd Schubert
2012-05-21 15:49 ` [PATCH] srp: convert SRP_RQ_SHIFT into a module parameter Bernd Schubert
[not found] ` <4FBA6412.7040505-mPn0NPGs4xGatNDF+KUbs4QuADTiUCJX@public.gmane.org>
2012-05-21 19:35 ` Bernd Schubert
2012-05-30 5:22 ` David Dillow
[not found] ` <1338355352.2361.24.camel-1q1vX8mYZiGLUyTwlgNVppKKF0rrzTr+@public.gmane.org>
2012-05-30 5:24 ` David Dillow
2012-05-17 9:09 ` multipath_busy() stalls IO due to scsi_host_is_busy() Jun'ichi Nomura
2012-05-17 13:46 ` Mike Snitzer
2012-05-21 15:42 ` Bernd Schubert
2012-05-22 4:31 ` Jun'ichi Nomura
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