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From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: socfpga: add smp_ops.cpu_kill to make kexec/kdump available
Date: Wed, 3 Jun 2015 00:52:39 +0100	[thread overview]
Message-ID: <20150602235239.GB7557@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <556E3F03.5040008@hitachi.com>

On Wed, Jun 03, 2015 at 08:40:51AM +0900, Hiraku Toyooka wrote:
> Hello, Russell,
> 
> On 2015/06/02 17:38, Russell King - ARM Linux wrote:
> > I wasn't thinking of SPIs and PPIs, but SGIs - the IPI interrupts coming
> > from the boot CPU.
> 
> All tasks in a CPU going offline are migrated to other CPUs(finally
> CPU0) and the rq is marked with offline before the CPU entering WFI
> loop. So IPI is not sent to the secondary CPU.
> 
> > If you have a way to reset CPU0, why are you not using this for hotplug
> > when a CPU is hot-unplugged?
> 
> I think you mean "way to reset CPU1". If so, the reason is an increase
> in power consumption in usual hotplug. This is discussed before between
> Alan Tull and you. (https://lkml.org/lkml/2014/9/25/37)

Please put a comment in your hotplug code describing this, so I'm
not likely to ask again (and I don't have to remember that I've
asked the question.)  Thanks.

-- 
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.

      reply	other threads:[~2015-06-02 23:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-29  5:38 [PATCH] ARM: socfpga: add smp_ops.cpu_kill to make kexec/kdump available Hiraku Toyooka
2015-05-29  8:33 ` Russell King - ARM Linux
2015-06-02  5:32   ` hiraku.toyooka.gu at hitachi.com
2015-06-02  8:38     ` Russell King - ARM Linux
2015-06-02 23:40       ` Hiraku Toyooka
2015-06-02 23:52         ` Russell King - ARM Linux [this message]

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