From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752857AbeCPOke (ORCPT ); Fri, 16 Mar 2018 10:40:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:48468 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751079AbeCPOkc (ORCPT ); Fri, 16 Mar 2018 10:40:32 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 856E321741 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Fri, 16 Mar 2018 10:40:30 -0400 From: Steven Rostedt To: Michael Ellerman Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, naveen.n.rao@linux.vnet.ibm.com Subject: Re: [RFC PATCH 1/2] ftrace: Allow arches to opt-out of static ftrace Message-ID: <20180316104030.0df39af7@gandalf.local.home> In-Reply-To: <20180316134633.10584-1-mpe@ellerman.id.au> References: <20180316134633.10584-1-mpe@ellerman.id.au> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.31; x86_64-pc-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 Sat, 17 Mar 2018 00:46:32 +1100 Michael Ellerman wrote: > There is a small but non-zero amount of code required by arches to > suppory non-dynamic (static) ftrace, and more importantly there is the > added work of testing both configurations. > > There are also almost no down sides to dynamic ftrace once it's well > tested, other than a small increase in code/data size. > > So give arches the option to opt-out of supporting static ftrace. > > This is implemented as a DYNAMIC_FTRACE_CHOICE option, which controls > whether DYNAMIC_FTRACE is presented as a user-selectable option or if > it is just enabled based on its dependencies being enabled (because > it's already default y). > > Then the CHOICE option depends on an arch *not* selecting > HAVE_DYNAMIC_FTRACE_ONLY. This would be more natural in reverse, as a > HAVE_STATIC_FTRACE option, but that would require updating every arch. > > Signed-off-by: Michael Ellerman Why not just add in arch/powerpc/Kconfig: config PPC [..] select DYNAMIC_FTRACE if FUNCTION_TRACER ? It seems to work for me. -- Steve