From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758843AbcIWNLm (ORCPT ); Fri, 23 Sep 2016 09:11:42 -0400 Received: from mail.kernel.org ([198.145.29.136]:46626 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754016AbcIWNLk (ORCPT ); Fri, 23 Sep 2016 09:11:40 -0400 Date: Fri, 23 Sep 2016 22:11:33 +0900 From: Masami Hiramatsu To: Masami Hiramatsu Cc: Steven Rostedt , Tom Zanussi , linux-kernel@vger.kernel.org, Ingo Molnar , Namhyung Kim Subject: Re: [PATCH] ftrace: trigger: Call traceoff trigger after event recorded Message-Id: <20160923221133.6ddd77b307900a02b6f15b71@kernel.org> In-Reply-To: <147335074530.12462.4526186083406015005.stgit@devbox> References: <147335074530.12462.4526186083406015005.stgit@devbox> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.30; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping? On Fri, 9 Sep 2016 01:05:45 +0900 Masami Hiramatsu wrote: > Call traceoff trigger after the event is recorded. > Since current traceoff trigger is called before recording > the event, we can not know when the trace is off by what event. > > Typical usecase of traceoff/traceon trigger is tracing > function calls and trace events between a pair of events. > For example, trace function calls between syscall entry/exit. > In that case, it is useful if we can see the return code > of the target syscall. > > Signed-off-by: Masami Hiramatsu > --- > kernel/trace/trace_events_trigger.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c > index a975571..6721a1e8 100644 > --- a/kernel/trace/trace_events_trigger.c > +++ b/kernel/trace/trace_events_trigger.c > @@ -1028,6 +1028,7 @@ static struct event_command trigger_traceon_cmd = { > static struct event_command trigger_traceoff_cmd = { > .name = "traceoff", > .trigger_type = ETT_TRACE_ONOFF, > + .flags = EVENT_CMD_FL_POST_TRIGGER, > .func = event_trigger_callback, > .reg = register_trigger, > .unreg = unregister_trigger, > -- Masami Hiramatsu