From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756151AbZDVJSV (ORCPT ); Wed, 22 Apr 2009 05:18:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753104AbZDVJSI (ORCPT ); Wed, 22 Apr 2009 05:18:08 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:57746 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752854AbZDVJSH (ORCPT ); Wed, 22 Apr 2009 05:18:07 -0400 Message-ID: <49EEE104.9050709@cn.fujitsu.com> Date: Wed, 22 Apr 2009 17:19:00 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Frederic Weisbecker CC: Ingo Molnar , Steven Rostedt , Tom Zanussi , LKML Subject: Re: [PATCH] tracing/events: make struct trace_entry->type to be int type References: <49EEDB0E.5070207@cn.fujitsu.com> <20090422091045.GA6031@nowhere> In-Reply-To: <20090422091045.GA6031@nowhere> 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 Frederic Weisbecker wrote: > On Wed, Apr 22, 2009 at 04:53:34PM +0800, Li Zefan wrote: >> struct trace_entry->type is unsigned char, while trace event's id is >> int type, thus for a event with id >= 256, it's entry->type is cast >> to (id % 256), and then we can't see the trace output of this event. >> >> # insmod trace-events-sample.ko >> # echo foo_bar > /mnt/tracing/set_event >> # cat /debug/tracing/events/trace-events-sample/foo_bar/id >> 256 >> # cat /mnt/tracing/trace_pipe >> <...>-3548 [001] 215.091142: Unknown type 0 >> <...>-3548 [001] 216.089207: Unknown type 0 >> <...>-3548 [001] 217.087271: Unknown type 0 >> <...>-3548 [001] 218.085332: Unknown type 0 >> >> [ Impact: fix output for trace events with id >= 256 ] >> >> Signed-off-by: Li Zefan > > > Indeed, now with the trace_events, we are approaching this possible > overflow and the type is indeed an int: > > struct trace_event *ftrace_find_event(int type) > > Curious: does it only happen with the trace-event-sample? > I doubt we already reached this threshold of event number. > But anyway, it's a good thing. > I guess we haven't reached this limit, at least for mainline. :) And the biggest id is 48 in my config. > Acked-by: Frederic Weisbecker