From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chanwoo Choi Subject: Re: [PATCH 1/3 v6] cpufreq: Add debugfs directory for cpufreq Date: Wed, 24 Jul 2013 18:05:33 +0900 Message-ID: <51EF98DD.4010607@samsung.com> References: <1374146275-5758-1-git-send-email-cw00.choi@samsung.com> <1374146275-5758-2-git-send-email-cw00.choi@samsung.com> <51EF2D06.7000704@samsung.com> <51EF8590.7030405@samsung.com> <51EF945E.3080802@samsung.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: Sender: cpufreq-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Viresh Kumar Cc: rjw@sisk.pl, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, cpufreq@vger.kernel.org, kyungmin.park@samsung.com, myungjoo.ham@samsung.com, Lists linaro-kernel On 07/24/2013 05:51 PM, Viresh Kumar wrote: > On 24 July 2013 14:16, Chanwoo Choi wrote: >> In case that all CPUs share same cpufreq policy. Each debugfs dentry of CPU[1-3] >> except for CPU0 has symbolic link to CPU0's debugfs directory as following. >> >> -sh-4.1# ls -al /sys/kernel/debug/cpufreq/ >> total 0 >> drwxr-xr-x 3 root root 0 Jan 1 09:00 . >> drwx------ 28 root root 0 Jan 1 09:00 .. >> drwxr-xr-x 2 root root 0 Jan 1 09:00 cpu0 (policy->cpu is 0) >> lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu1 -> ./cpu0 >> lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu2 -> ./cpu0 >> lrwxrwxrwx 1 root root 0 Jan 1 09:00 cpu3 -> ./cpu0 >> >> If turn off CPU0 state, I have to move debugfs directory data from cpu0 to cpu1 >> and again create link to cpu1's debugfs directory for CPU[2-3] debugfs directory. >> So, I removed dentry link of CPU[1-3] before creating link again. >> >> cpu1 >> cpu2 -> ./cpu1 >> cpu3 -> ./cpu1 >> >> But I can rewrite new link of CPU[2-3] to previous dentry link(policy->cpu_debugfs[2] or policy->cpu_debugfs[3]) >> for reducing unnecessary code without revmoval sequence. > > Because we aren't freeing the debugfs node at all (just renaming > it), the links might still be good after renaming.. But please check > if it is true. > > So, according to me you need to do this: > - Remove symlink for new policy->cpu, i..e cpu1 in your example > - rename debugfs entry to give it to cpu1 instead of cpu0. > - Set cpu0 pointer to NULL. > > Probably that's it. > And, I add additional step on below: > - Remove symlink for new policy->cpu, i..e cpu1 in your example > - rename debugfs entry to give it to cpu1 instead of cpu0. - Store renamed cpu0 pointer to cpu1 pointer - Create new link for CPU[2-3] to CPU1's debugfs directory because debugfs use string path to create symbolic link. It isn't automatically connected with new CPU1 debugfs directory. > - Set cpu0 pointer to NULL. > Thanks, Chanwoo Choi