From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755172AbZJ1U6o (ORCPT ); Wed, 28 Oct 2009 16:58:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754969AbZJ1U6n (ORCPT ); Wed, 28 Oct 2009 16:58:43 -0400 Received: from pfepa.post.tele.dk ([195.41.46.235]:58343 "EHLO pfepa.post.tele.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754883AbZJ1U6l (ORCPT ); Wed, 28 Oct 2009 16:58:41 -0400 Date: Wed, 28 Oct 2009 21:58:44 +0100 From: Sam Ravnborg To: Ingo Molnar Cc: Pekka Enberg , mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, ink@jurassic.park.msu.ru, tglx@linutronix.de, rth@twiddle.net, mcree@orcon.net.nz, linux-tip-commits@vger.kernel.org Subject: Re: [tip:perf/core] perf tools, Alpha: Add Alpha support to perf.h Message-ID: <20091028205844.GC20363@merkur.ravnborg.org> References: <1256545926-6972-1-git-send-email-mcree@orcon.net.nz> <84144f020910260508n47ef067ci4adfd02cd3f87edd@mail.gmail.com> <20091026122247.GA31982@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091026122247.GA31982@elte.hu> 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 > > > > OK, I'll bite. We tell userspace developers not to include kernel > > headers. Why is it okay for perf to do it (especially for something > > that's in asm)? > > The main counter-argument against inclusion was always "what if we break > them accidentally". I.e. it can become a semi-ABI - stuff we cannot > change because we cannot change the outside projects. With perf this > cannot occur - it's all in one Git tree and can always be fixed/changed. > > Note that we reuse a couple of other facilities in tools/perf as well - > linux/list.h, rbtree.c, etc. - and this is good - you can code perf as > if you were hacking on the kernel! ;-) I see no reasons why perf should not use the exported headers in the default case. unistd.h from alpha is indeed exported. If perf then on top of that uses some kernel internal stuff - then pick it up there. But having perf in the kernel is not an excuse for avoinding the exported headers. Sam