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From: Thomas Gleixner <tglx@linutronix.de>
To: Shivasharan Srikanteshwara  <shivasharan.srikanteshwara@broadcom.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>,
	Kashyap Desai <kashyap.desai@broadcom.com>,
	Hannes Reinecke <hare@suse.de>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Christoph Hellwig <hch@lst.de>,
	axboe@kernel.dk, mpe@ellerman.id.au, keith.busch@intel.com,
	peterz@infradead.org, LKML <linux-kernel@vger.kernel.org>,
	linux-scsi@vger.kernel.org,
	Sumit Saxena <sumit.saxena@broadcom.com>
Subject: RE: system hung up when offlining CPUs
Date: Wed, 1 Nov 2017 01:47:01 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1711010105260.1942@nanos> (raw)
In-Reply-To: <817f0d359fca6830ece5b1fcf207ce65@mail.gmail.com>

On Mon, 30 Oct 2017, Shivasharan Srikanteshwara wrote:

> In managed-interrupts case, interrupts which were affine to the offlined
> CPU is not getting migrated to another available CPU. But the
> documentation at below link says that "all interrupts" are migrated to a
> new CPU. So not all interrupts are getting migrated to a new CPU then.

Correct.

> https://www.kernel.org/doc/html/v4.11/core-api/cpu_hotplug.html#the-offlin
> e-case
> "- All interrupts targeted to this CPU are migrated to a new CPU"

Well, documentation is not always up to date :)
 
> Once the last CPU in the affinity mask is offlined and a particular IRQ
> is shutdown, is there a way currently for the device driver to get
> callback to complete all outstanding requests on that queue?

No and I have no idea how the other drivers deal with that.

The way you can do that is to have your own hotplug callback which is
invoked when the cpu goes down, but way before the interrupt is shut down,
which is one of the last steps. Ideally this would be a callback in the
generic block code which then calls out to all instances like its done for
the cpu dead state.

Jens, Christoph?

Thanks,

	tglx

  reply	other threads:[~2017-11-01  0:47 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-08 19:25 system hung up when offlining CPUs YASUAKI ISHIMATSU
2017-08-09 11:42 ` Marc Zyngier
2017-08-09 19:09   ` YASUAKI ISHIMATSU
2017-08-10 11:54     ` Marc Zyngier
2017-08-21 12:07       ` Christoph Hellwig
2017-08-21 13:18       ` Christoph Hellwig
2017-08-21 13:37         ` Marc Zyngier
2017-09-07 20:23           ` YASUAKI ISHIMATSU
2017-09-12 18:15             ` YASUAKI ISHIMATSU
2017-09-13 11:13               ` Hannes Reinecke
2017-09-13 11:35                 ` Kashyap Desai
2017-09-13 13:33                   ` Thomas Gleixner
2017-09-14 16:28                     ` YASUAKI ISHIMATSU
2017-09-16 10:15                       ` Thomas Gleixner
2017-09-16 15:02                         ` Thomas Gleixner
2017-10-02 16:36                           ` YASUAKI ISHIMATSU
2017-10-03 21:44                             ` Thomas Gleixner
2017-10-04 21:04                               ` Thomas Gleixner
2017-10-09 11:35                                 ` [tip:irq/urgent] genirq/cpuhotplug: Add sanity check for effective affinity mask tip-bot for Thomas Gleixner
2017-10-09 11:35                                 ` [tip:irq/urgent] genirq/cpuhotplug: Enforce affinity setting on startup of managed irqs tip-bot for Thomas Gleixner
2017-10-10 16:30                                 ` system hung up when offlining CPUs YASUAKI ISHIMATSU
2017-10-16 18:59                                   ` YASUAKI ISHIMATSU
2017-10-16 20:27                                     ` Thomas Gleixner
2017-10-30  9:08                                       ` Shivasharan Srikanteshwara
2017-11-01  0:47                                         ` Thomas Gleixner [this message]
2017-11-01 11:01                                           ` Hannes Reinecke
2017-10-04 21:10                             ` Thomas Gleixner
  -- strict thread matches above, loose matches on Subject: below --
2017-08-08 19:24 YASUAKI ISHIMATSU

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