DomainKey-Signature: a=rsa-sha1; c=nofws;
        d=gmail.com; s=gamma;
        h=date:from:to:cc:subject:message-id:references:mime-version
         :content-type:content-disposition:in-reply-to:user-agent;
        b=bhvO+H4WqExsm7SXVfk+XyVykCNVBl7CMfBd97kpwheyDQ97bnuG/WrxMxiXFJyyhF
         C1+e4QLKW1HVrA7OD2GV1iuxUGHUgjJ0MzUsW7U1kG2dwzbvtB08jA+g4y0gLtjEY8+n
         ipuaG9wg2FLKSpwlFpY6bub4guyISeoxV0yEg=
Date: Sun, 21 Nov 2010 23:03:45 +0800
From: =?utf-8?Q?Am=C3=A9rico?= Wang <xiyou.wangcong@gmail.com>
To: shaohui.zheng@intel.com
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, haicheng.li@linux.intel.com,
        lethal@linux-sh.org, ak@linux.intel.com, shaohui.zheng@linux.intel.com,
        Haicheng Li <haicheng.li@intel.com>
Subject: Re: [8/8,v3] NUMA Hotplug Emulator: documentation
Message-ID: <20101121150344.GK9099@hack>
References: <20101117020759.016741414@intel.com> <20101117021000.985643862@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20101117021000.985643862@intel.com>
User-Agent: Mutt/1.5.19 (2009-01-05)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1798
Lines: 47

On Wed, Nov 17, 2010 at 10:08:07AM +0800, shaohui.zheng@intel.com wrote:
>+2) CPU hotplug emulation:
>+
>+The emulator reserve CPUs throu grub parameter, the reserved CPUs can be
>+hot-add/hot-remove in software method, it emulates the process of physical
>+cpu hotplug.
>+
>+When hotplug a CPU with emulator, we are using a logical CPU to emulate the CPU
>+socket hotplug process. For the CPU supported SMT, some logical CPUs are in the
>+same socket, but it may located in different NUMA node after we have emulator.
>+We put the logical CPU into a fake CPU socket, and assign it an unique
>+phys_proc_id. For the fake socket, we put one logical CPU in only.
>+
>+ - to hide CPUs
>+	- Using boot option "maxcpus=N" hide CPUs
>+	  N is the number of initialize CPUs
>+	- Using boot option "cpu_hpe=on" to enable cpu hotplug emulation
>+      when cpu_hpe is enabled, the rest CPUs will not be initialized
>+
>+ - to hot-add CPU to node
>+	$ echo nid > cpu/probe
>+
>+ - to hot-remove CPU
>+	$ echo nid > cpu/release
>+

Again, we already have software CPU hotplug,
i.e. /sys/devices/system/cpu/cpuX/online.

You need to pick up another name for this.

>From your documentation above, it looks like you are trying
to move one CPU between nodes?

>+	cpu_hpe=on/off
>+		Enable/disable cpu hotplug emulation with software method. when cpu_hpe=on,
>+		sysfs provides probe/release interface to hot add/remove cpu dynamically.
>+		this option is disabled in default.
>+			

Why not just a CONFIG? IOW, why do we need to make another boot
parameter for this?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/