From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754502Ab0ENCNg (ORCPT ); Thu, 13 May 2010 22:13:36 -0400 Received: from mga05.intel.com ([192.55.52.89]:56898 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751613Ab0ENCNe (ORCPT ); Thu, 13 May 2010 22:13:34 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,226,1272870000"; d="scan'208";a="798319939" Message-ID: <4BECB1CB.2030802@linux.intel.com> Date: Fri, 14 May 2010 10:13:31 +0800 From: Haicheng Li User-Agent: Thunderbird 2.0.0.23 (X11/20090812) MIME-Version: 1.0 To: Dave Hansen CC: Greg KH , akpm@linux-foundation.org, linux-mm@kvack.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Hidetoshi Seto , David Rientjes , Alex Chiang , linux-kernel@vger.kernel.org, ak@linux.intel.com, fengguang.wu@intel.com, shaohui.zheng@linux.intel.com Subject: Re: [RFC, 3/7] NUMA hotplug emulator References: <20100513114835.GD2169@shaohui> <20100513165511.GB25212@suse.de> <1273773292.13285.7755.camel@nimitz> In-Reply-To: <1273773292.13285.7755.camel@nimitz> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Hansen wrote: > On Thu, 2010-05-13 at 09:55 -0700, Greg KH wrote: >>> Add a sysfs entry "probe" under /sys/devices/system/node/: >>> >>> - to show all fake offlined nodes: >>> $ cat /sys/devices/system/node/probe >>> >>> - to hotadd a fake offlined node, e.g. nodeid is N: >>> $ echo N > /sys/devices/system/node/probe >> As you are trying to add a new sysfs file, please create the matching >> Documentation/ABI/ file as well. >> >> Also note that sysfs files are "one value per file", which I don't think >> this file follows, right? > > I think in this case, it was meant to be a list of acceptable parameters > rather than a set of values, kinda like /sys/power/state. Right. > Instead, I guess we could have: > > /sys/devices/system/node/probeable/3 > /sys/devices/system/node/probeable/43 > /sys/devices/system/node/probeable/65 > /sys/devices/system/node/probeable/5145 > > and the knowledge that you need to pick one of those to echo > into /sys/devices/system/node/probe. I think this way would make things complex if we just want to show user which node could be hotadded. > But, it's a lot more self > explanatory if you 'cat /sys/devices/system/node/probe', and then pick > one of those to echo back into the file. agreed. > Seems like a decent place to violate the "rule". :)