From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755142AbYKKDhk (ORCPT ); Mon, 10 Nov 2008 22:37:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754210AbYKKDha (ORCPT ); Mon, 10 Nov 2008 22:37:30 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:59367 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754192AbYKKDha (ORCPT ); Mon, 10 Nov 2008 22:37:30 -0500 Date: Mon, 10 Nov 2008 19:37:13 -0800 From: Andrew Morton To: Valdis.Kletnieks@vt.edu Cc: linux-kernel@vger.kernel.org, Ken Chen , Ingo Molnar Subject: Re: 2.6.28-rc4-mmotm1110 - you gotta be kidding me... Message-Id: <20081110193713.d94ed39a.akpm@linux-foundation.org> In-Reply-To: <30622.1226372137@turing-police.cc.vt.edu> References: <30622.1226372137@turing-police.cc.vt.edu> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Nov 2008 21:55:37 -0500 Valdis.Kletnieks@vt.edu wrote: > Somebody's been hitting the phunky pharmaceuticals in the last 4 days, > because this ball-of-joy snuck into linux-next.patch sometime between > -mmotm1106 and --mmotm1110. > > Seen in a 'make silentallconfig' > > Single-depth WCHAN output (SCHED_NO_NO_OMIT_FRAME_POINTER) [Y/n/?] (NEW) ? > > Calculate simpler /proc//wchan values. If this option > is disabled then wchan values will recurse back to the > caller function. This provides more accurate wchan values, > at the expense of slightly more scheduling overhead. I got lost here. > If in doubt, say "Y". > > So if I say 'y', is that a request to disable it, or enable it? And > what exactly do I get if I vote *against* 'more accurate wchan values'? > Do I get everybody having the same wchan pointing somewhere in the > scheduler code, because that's where __builtin_return_address() points? > > And please - a triple negative in the Kconfig variable name? This has > gotta be a winner for poor taste in variable naming... > Even if that is all sorted out, how the heck is anyone to decide whether or not they need this thing? Also, if we really really are so wishy-washy indecisive that we need to make the function optional, it should if at all possible be made runtime-configurable, not compile-time.