From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758511AbaDVUkP (ORCPT ); Tue, 22 Apr 2014 16:40:15 -0400 Received: from mail-qc0-f176.google.com ([209.85.216.176]:41157 "EHLO mail-qc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758189AbaDVUkK (ORCPT ); Tue, 22 Apr 2014 16:40:10 -0400 Date: Tue, 22 Apr 2014 16:40:06 -0400 From: Tejun Heo To: Li Zhong Cc: LKML , gregkh@linuxfoundation.org, rafael.j.wysocki@intel.com, toshi.kani@hp.com Subject: Re: [RFC PATCH v5 1/2] Use lock_device_hotplug() in cpu_probe_store() and cpu_release_store() Message-ID: <20140422204006.GA3615@mtj.dyndns.org> References: <20140414201315.GD16835@htj.dyndns.org> <1397529877.13188.68.camel@ThinkPad-T5421.cn.ibm.com> <20140415145017.GK1863@htj.dyndns.org> <1397612500.13188.83.camel@ThinkPad-T5421.cn.ibm.com> <20140416151749.GE1257@htj.dyndns.org> <1397717444.4034.15.camel@ThinkPad-T5421> <20140417151728.GK15326@htj.dyndns.org> <1398072059.2755.41.camel@ThinkPad-T5421.cn.ibm.com> <20140421223804.GD22730@htj.dyndns.org> <1398133777.2805.7.camel@ThinkPad-T5421.cn.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1398133777.2805.7.camel@ThinkPad-T5421.cn.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Apr 22, 2014 at 10:29:37AM +0800, Li Zhong wrote: > The probe/release files are attribute files for cpu subsys, looks like > following in sysfs dirs > > $ cd /sys/devices/system/cpu/ > $ ls -l > total 0 > drwxr-xr-x. 7 root root 0 Apr 17 19:00 cpu0 > drwxr-xr-x. 4 root root 0 Apr 17 19:00 cpu1 > drwxr-xr-x. 4 root root 0 Apr 17 19:00 cpu10 > ...... > drwxr-xr-x. 3 root root 0 Apr 20 08:00 cpufreq > drwxr-xr-x. 2 root root 0 Apr 20 08:00 cpuidle > -rw-------. 1 root root 65536 Apr 21 00:28 dscr_default > -r--r--r--. 1 root root 65536 Apr 21 00:28 kernel_max > -r--r--r--. 1 root root 65536 Apr 21 00:28 offline > -r--r--r--. 1 root root 65536 Sep 4 2014 online > -r--r--r--. 1 root root 65536 Apr 21 00:28 possible > drwxr-xr-x. 2 root root 0 Apr 20 08:00 power > -r--r--r--. 1 root root 65536 Apr 17 20:46 present > --w-------. 1 root root 65536 Apr 21 00:28 probe <----- > --w-------. 1 root root 65536 Apr 21 00:28 release <----- > -rw-------. 1 root root 65536 Apr 21 00:28 subcores_per_core > -rw-r--r--. 1 root root 65536 Apr 21 00:28 uevent > > From the code, it seems cpu subsys won't be unregistered, and it doesn't > make sense to remove all the cpus in the system. I don't think I'm following you. Are you saying that no files which are protected under the hotplug lock that cpu subsys uses are removed during offlining? Thanks. -- tejun