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From: Benjamin Block <bblock@linux.ibm.com>
To: John Garry <john.garry@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Keith Busch <keith.busch@intel.com>,
	Hannes Reinecke <hare@suse.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Marc Zyngier <marc.zyngier@arm.com>,
	"axboe@kernel.dk" <axboe@kernel.dk>,
	Peter Zijlstra <peterz@infradead.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Linuxarm <linuxarm@huawei.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Hannes Reinecke <hare@suse.com>,
	"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: Question on handling managed IRQs when hotplugging CPUs
Date: Wed, 6 Feb 2019 14:34:32 +0100	[thread overview]
Message-ID: <20190206133432.GB14106@t480-pf1aa2c2> (raw)
In-Reply-To: <3413b0b1-cb3f-3b09-106d-89cf8be30178@huawei.com>

On Wed, Feb 06, 2019 at 09:21:40AM +0000, John Garry wrote:
> On 05/02/2019 18:23, Christoph Hellwig wrote:
> > On Tue, Feb 05, 2019 at 03:09:28PM +0000, John Garry wrote:
> > > For SCSI devices, unfortunately not all IO sent to the HW originates from
> > > blk-mq or any other single entity.
> > 
> > Where else would SCSI I/O originate from?
> 
> Please note that I was referring to other management IO, like SAS SMP, TMFs,
> and other proprietary commands which the driver may generate for the HBA -
> https://marc.info/?l=linux-scsi&m=154831889001973&w=2 discusses some of them
> also.
> 

Especially the TMFs send via SCSI EH are a bit of a pain I guess,
because they are entirely managed by the device drivers, but depending
on the device driver they might not even qualify for the problem Hannes
is seeing.

-- 
With Best Regards, Benjamin Block      /      Linux on IBM Z Kernel Development
IBM Systems & Technology Group   /  IBM Deutschland Research & Development GmbH
Vorsitz. AufsR.: Matthias Hartmann       /      Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: AmtsG Stuttgart, HRB 243294


  reply	other threads:[~2019-02-06 13:34 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <f6f6e031-8b79-439d-c2af-8d3e76f30710@huawei.com>
     [not found] ` <20190129154433.GF15302@localhost.localdomain>
     [not found]   ` <757902fc-a9ea-090b-7853-89944a0ce1b5@huawei.com>
     [not found]     ` <20190129172059.GC17132@localhost.localdomain>
     [not found]       ` <3fe63dab-0791-f476-69c4-9866b70e8520@huawei.com>
     [not found]         ` <alpine.DEB.2.21.1901301338170.5537@nanos.tec.linutronix.de>
2019-01-31 17:48           ` Question on handling managed IRQs when hotplugging CPUs John Garry
2019-02-01 15:56             ` Hannes Reinecke
2019-02-01 21:57               ` Thomas Gleixner
2019-02-04  7:12                 ` Hannes Reinecke
2019-02-05 13:24                   ` John Garry
2019-02-05 14:52                     ` Keith Busch
2019-02-05 15:09                       ` John Garry
2019-02-05 15:11                         ` Keith Busch
2019-02-05 15:15                         ` Hannes Reinecke
2019-02-05 15:27                           ` John Garry
2019-02-05 18:23                         ` Christoph Hellwig
2019-02-06  9:21                           ` John Garry
2019-02-06 13:34                             ` Benjamin Block [this message]
2019-02-05 15:10                       ` Hannes Reinecke
2019-02-05 15:16                         ` Keith Busch

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