Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755202AbYHGScy (ORCPT ); Thu, 7 Aug 2008 14:32:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751024AbYHGScq (ORCPT ); Thu, 7 Aug 2008 14:32:46 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:45114 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750813AbYHGScq (ORCPT ); Thu, 7 Aug 2008 14:32:46 -0400 Date: Thu, 7 Aug 2008 14:32:44 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: "Frank Ch. Eigler" cc: Mathieu Desnoyers , Ingo Molnar , Thomas Gleixner , James Bottomley , akpm@linux-foundation.org, Peter Zijlstra , linux-kernel@vger.kernel.org, ltt-dev@lists.casi.polymtl.ca Subject: Re: LTTng finds abnormally long APIC interrupt handler : 58.2 ms In-Reply-To: Message-ID: References: <20080805182007.GA4631@Krystal> <20080807160907.GA11255@Krystal> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1218 Lines: 29 On Thu, 7 Aug 2008, Frank Ch. Eigler wrote: > Steven Rostedt writes: > > > > I've been thinking of exporting it, and make it so that once you > > register something to the trace_ops, I'll up the module count, and never > > let that module unload. > > This issue will need some sort of resolution if systemtap is to be > able to hook up to ftrace. Perhaps we could have a second/nested API > that suffers the costs of explicit reference counting, but does permit > dynamic attach and robust detach. I've also thought about having a second registration method that would hook the mcount function to an internal one, one that is always there. Here we could add logic to know that a driver has registered a function. It will just have the added overhead of that logic. It's not hard to do. I just didn't want to clutter ftrace too much before it made it into a major release. This means any patches to do this will happen after 27. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/