From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757838AbaAJPVv (ORCPT ); Fri, 10 Jan 2014 10:21:51 -0500 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.225]:43231 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753379AbaAJPVE (ORCPT ); Fri, 10 Jan 2014 10:21:04 -0500 Message-Id: <20140110152100.763984865@goodmis.org> User-Agent: quilt/0.60-1 Date: Fri, 10 Jan 2014 10:20:09 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Frederic Weisbecker , Andrew Morton Subject: [for-next][PATCH 5/5] tracing: Show available event triggers when no trigger is set References: <20140110152004.200225053@goodmis.org> Content-Disposition: inline; filename=0005-tracing-Show-available-event-triggers-when-no-trigge.patch X-RR-Connecting-IP: 107.14.168.118:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (Red Hat)" Currently there's no way to know what triggers exist on a kernel without looking at the source of the kernel or randomly trying out triggers. Instead of creating another file in the debugfs system, simply show what available triggers are there when cat'ing the trigger file when it has no events: [root /sys/kernel/debug/tracing]# cat events/sched/sched_switch/trigger # Available triggers: # traceon traceoff snapshot stacktrace enable_event disable_event This stays consistent with other debugfs files where meta data like this is always proceeded with a '#' at the start of the line so that tools can strip these out. Link: http://lkml.kernel.org/r/20140107103548.0a84536d@gandalf.local.home Signed-off-by: Steven Rostedt --- kernel/trace/trace_events_trigger.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index a53e0da..8efbb69 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -115,10 +115,15 @@ event_triggers_post_call(struct ftrace_event_file *file, } EXPORT_SYMBOL_GPL(event_triggers_post_call); +#define SHOW_AVAILABLE_TRIGGERS (void *)(1UL) + static void *trigger_next(struct seq_file *m, void *t, loff_t *pos) { struct ftrace_event_file *event_file = event_file_data(m->private); + if (t == SHOW_AVAILABLE_TRIGGERS) + return NULL; + return seq_list_next(t, &event_file->triggers, pos); } @@ -132,6 +137,9 @@ static void *trigger_start(struct seq_file *m, loff_t *pos) if (unlikely(!event_file)) return ERR_PTR(-ENODEV); + if (list_empty(&event_file->triggers)) + return *pos == 0 ? SHOW_AVAILABLE_TRIGGERS : NULL; + return seq_list_start(&event_file->triggers, *pos); } @@ -143,6 +151,18 @@ static void trigger_stop(struct seq_file *m, void *t) static int trigger_show(struct seq_file *m, void *v) { struct event_trigger_data *data; + struct event_command *p; + + if (v == SHOW_AVAILABLE_TRIGGERS) { + seq_puts(m, "# Available triggers:\n"); + seq_putc(m, '#'); + mutex_lock(&trigger_cmd_mutex); + list_for_each_entry_reverse(p, &trigger_commands, list) + seq_printf(m, " %s", p->name); + seq_putc(m, '\n'); + mutex_unlock(&trigger_cmd_mutex); + return 0; + } data = list_entry(v, struct event_trigger_data, list); data->ops->print(m, data->ops, data); -- 1.8.4.3