From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759157AbZHROUi (ORCPT ); Tue, 18 Aug 2009 10:20:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752604AbZHROUh (ORCPT ); Tue, 18 Aug 2009 10:20:37 -0400 Received: from mx2.redhat.com ([66.187.237.31]:54963 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750886AbZHROUg (ORCPT ); Tue, 18 Aug 2009 10:20:36 -0400 Date: Tue, 18 Aug 2009 10:19:06 -0400 From: Jason Baron To: Josh Stone Cc: linux-kernel@vger.kernel.org, fweisbec@gmail.com, mingo@elte.hu, laijs@cn.fujitsu.com, rostedt@goodmis.org, peterz@infradead.org, mathieu.desnoyers@polymtl.ca, jiayingz@google.com, mbligh@google.com, lizf@cn.fujitsu.com Subject: Re: [PATCH] tracing: Move tracepoint callbacks into DEFINE Message-ID: <20090818141906.GA2669@redhat.com> References: <1250580227-24363-1-git-send-email-jistone@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1250580227-24363-1-git-send-email-jistone@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 18, 2009 at 12:23:47AM -0700, Josh Stone wrote: > It's not strictly correct for the tracepoint reg/unreg callbacks to > occur when a client is hooking up, because the actual tracepoint may no > be present yet. This happens to be fine for syscall, since that's in > the core kernel, but it would cause problems for tracepoints defined in > a module that hasn't been loaded yet. It also means the reg/unreg has > to be EXPORTed for any modules to use the tracepoint (as in SystemTap). > > This patch removes DECLARE_TRACE_WITH_CALLBACK, and instead introduces > DEFINE_TRACE_WITH_CALLBACK which stores the callbacks in struct > tracepoint. The callbacks are used now when the active state of the > tracepoint changes in set_tracepoint & disable_tracepoint. > > This also introduces TRACE_EVENT_WITH_CALLBACK, so those events can also > provide callbacks if needed. > this makes sense...Ingo also suggested having the two high level tracepoints be 'TRACE_EVENT' style. That is we should be able to register with the syscall entry and get the *all* the syscall numbers and arguments, and likewise on exit we should be able to get *all* syscall exit return values. see: http://marc.info/?l=linux-kernel&m=125008740803571&w=2 does this patch allow/do that? thanks, -Jason