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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Magnus Damm <magnus.damm@gmail.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>,
	Simon Horman <horms@verge.net.au>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Nicolas Pitre <nico@linaro.org>,
	Dave Martin <Dave.Martin@arm.com>,
	SH-Linux <linux-sh@vger.kernel.org>
Subject: Re: [PATCH v2] ARM: smp: Only expose /sys/.../cpuX/online if hotpluggable
Date: Fri, 13 Feb 2015 22:58:54 +0000	[thread overview]
Message-ID: <20150213225854.GG8656@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <CANqRtoSOBf3ZCKdKYta-P2q==ZMHk=VZgfEztPJ+uaKQtkBWjg@mail.gmail.com>

On Fri, Feb 13, 2015 at 08:54:22PM +0000, Magnus Damm wrote:
> Thanks for your efforts. Can you please tell me where that limitation
> is located? I'm quite sure I've brought CPU cores up and down
> including CPU0, but maybe something is missing?

If you don't provide a cpu_disable function, by default only the non-boot
(iow, non-CPU0) CPUs can be hotplugged.

If you provide a cpu_disable function, it can instruct the system that
fewer or more CPUs can be hotplugged, including the boot CPU.  The system
will then restrict you to a minimum of any one CPU online.

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

  parent reply	other threads:[~2015-02-13 22:59 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-13 18:06 [PATCH v2] ARM: smp: Only expose /sys/.../cpuX/online if hotpluggable Stephen Boyd
2015-02-13 20:20 ` Simon Horman
2015-02-13 20:23   ` Stephen Boyd
2015-02-13 20:54     ` Magnus Damm
2015-02-13 20:59       ` Stephen Boyd
2015-02-13 21:44         ` Magnus Damm
2015-02-13 23:01           ` Russell King - ARM Linux
2015-02-14  0:01             ` Stephen Boyd
2015-02-14 10:01             ` Magnus Damm
2015-02-16 15:29             ` Mark Rutland
2015-02-13 22:58       ` Russell King - ARM Linux [this message]
2015-02-13 22:57   ` Russell King - ARM Linux
2015-02-13 23:24     ` Simon Horman

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