From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1752783AbYKZHTJ@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1752783AbYKZHTJ (ORCPT <rfc822;w@1wt.eu>);
	Wed, 26 Nov 2008 02:19:09 -0500
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750981AbYKZHS4
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Wed, 26 Nov 2008 02:18:56 -0500
Received: from mx2.mail.elte.hu ([157.181.151.9]:34069 "EHLO mx2.mail.elte.hu"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1750696AbYKZHS4 (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 26 Nov 2008 02:18:56 -0500
Date: Wed, 26 Nov 2008 08:18:34 +0100
From: Ingo Molnar <mingo@elte.hu>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
       Dave Hansen <dave@linux.vnet.ibm.com>,
       Andrew Morton <akpm@linux-foundation.org>, containers@lists.osdl.org,
       fweisbec@gmail.com, LKML <linux-kernel@vger.kernel.org>,
       srostedt@redhat.com, Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>,
       "Serge E. Hallyn" <serue@us.ibm.com>
Subject: Re: [PATCH 1/3] ftrace: add function tracing to single thread
Message-ID: <20081126071834.GF26036@elte.hu>
References: <alpine.DEB.1.10.0811251800130.26424@gandalf.stny.rr.com> <20081125153104.ecdceed4.akpm@linux-foundation.org> <alpine.DEB.1.10.0811251909320.26424@gandalf.stny.rr.com> <1227660839.12109.52.camel@nimitz> <alpine.DEB.1.10.0811251956570.26424@gandalf.stny.rr.com> <m1zljndrb6.fsf@frodo.ebiederm.org> <alpine.DEB.1.10.0811260000400.26424@gandalf.stny.rr.com> <m1abbnc8ff.fsf@frodo.ebiederm.org> <20081126063201.GF9732@elte.hu> <m1zljn7yx9.fsf@frodo.ebiederm.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <m1zljn7yx9.fsf@frodo.ebiederm.org>
User-Agent: Mutt/1.5.18 (2008-05-17)
X-ELTE-VirusStatus: clean
X-ELTE-SpamScore: -1.5
X-ELTE-SpamLevel: 
X-ELTE-SpamCheck: no
X-ELTE-SpamVersion: ELTE 2.0 
X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3
	-1.5 BAYES_00               BODY: Bayesian spam probability is 0 to 1%
	[score: 0.0000]
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


* Eric W. Biederman <ebiederm@xmission.com> wrote:

> Ingo Molnar <mingo@elte.hu> writes:
> 
> > i dont see the point of the complexity you are advocating. 99.9% of 
> > the users run a unique PID space.
> 
> I'm not advocating complexity.  I'm advocating using the same APIs as
> the rest of the kernel, for doing the same functions.
> 
> > Tracing is about keeping stuff simple. On containers we could also 
> > trace the namespace ID (is there an easy ID for the namespace, as an 
> > easy extension to the very nice PID concept that Unix introduced 
> > decades ago?) and be done with it.
> 
> I don't really care about the pid namespace in this context.
> 
> I am just asking that we compare a different field in the task 
> struct.
> 
> I am asking that we don't accumulate new users of an old crufty bug 
> prone API, for no good reason.

i dont disagree about the change, but i'm curious, what's bug-prone 
about current->pid? It certainly worked quite well for the first 15 
years.

	Ingo