From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752134AbZGTA5g (ORCPT ); Sun, 19 Jul 2009 20:57:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752014AbZGTA5f (ORCPT ); Sun, 19 Jul 2009 20:57:35 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:58736 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752012AbZGTA5e (ORCPT ); Sun, 19 Jul 2009 20:57:34 -0400 Message-ID: <4A63C09A.80904@cn.fujitsu.com> Date: Mon, 20 Jul 2009 08:55:54 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Jiri Olsa CC: Ingo Molnar , Steven Rostedt , lkml Subject: Re: [PATCH] tracing: dont reset set_ftrace_filter/notrace when opened with r/w perm References: <20090716165135.GA4739@jolsa.lab.eng.brq.redhat.com> <4A604654.1090303@cn.fujitsu.com> <20090717111025.GC2891@jolsa.lab.eng.brq.redhat.com> In-Reply-To: <20090717111025.GC2891@jolsa.lab.eng.brq.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jiri Olsa wrote: > On Fri, Jul 17, 2009 at 05:37:24PM +0800, Li Zefan wrote: >> Jiri Olsa wrote: >>> If user setup set_ftrace_filter/set_ftrace_notrace files and then opens them >>> with read&write permissions, the previous setup will be removed. >>> >> Currently: >> >> # echo 'sys_open sys_close' > set_ftrace_filter >> # cat set_ftrace_filter >> sys_open >> sys_close >> >> After your patch: >> >> # echo 'sys_open sys_close' > set_ftrace_filter >> # cat set_ftrace_filter >> sys_close >> > > oops, sry I missed this.. > > Following patch adds new FTRACE_ITER_RESET flag, as the decision needs > to be taken in "open" and applied in "write". I'm not sure whats the > policy for adding new flags, but it looks ok to me. > I have no strong opinion whether to do the reset in "open" or in first "write". All said, I think this is cleaner, without introducing a new flag: @@ -2260,6 +2256,9 @@ ftrace_regex_write(struct file *file, const char __user *ubuf, return 0; mutex_lock(&ftrace_regex_lock); + if (file->f_pos == 0 && + (file->f_mode & FMODE_WRITE) && !(file->f_flags & O_APPEND)) + ftrace_filter_reset(enable); if (file->f_mode & FMODE_READ) { struct seq_file *m = file->private_data;