From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 284306B0071 for ; Sun, 21 Nov 2010 10:00:45 -0500 (EST) Received: by gxk7 with SMTP id 7so4015598gxk.14 for ; Sun, 21 Nov 2010 07:00:42 -0800 (PST) Date: Sun, 21 Nov 2010 23:03:45 +0800 From: =?utf-8?Q?Am=C3=A9rico?= Wang 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> Sender: owner-linux-mm@kvack.org 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 List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org