From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: linux-next: build failure after merge of the tip tree Date: Tue, 21 Jan 2014 11:47:21 +0100 Message-ID: <20140121104721.GB4105@gmail.com> References: <20140116121955.GQ31570@twins.programming.kicks-ass.net> <20140117074628.88698f59939c9002b7c12968@canb.auug.org.au> <20140120082620.GB30183@twins.programming.kicks-ass.net> <52DCE4CF.2060605@zytor.com> <20140120091600.GW31570@twins.programming.kicks-ass.net> <52DCEAF4.3040902@zytor.com> <20140120092931.GA3836@gmail.com> <20140120215151.GN31570@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-ee0-f41.google.com ([74.125.83.41]:45472 "EHLO mail-ee0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754185AbaAUKrZ (ORCPT ); Tue, 21 Jan 2014 05:47:25 -0500 Content-Disposition: inline In-Reply-To: <20140120215151.GN31570@twins.programming.kicks-ass.net> Sender: linux-next-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: Len Brown , "H. Peter Anvin" , Stephen Rothwell , Thomas Gleixner , Ingo Molnar , linux-next@vger.kernel.org, "linux-kernel@vger.kernel.org" * Peter Zijlstra wrote: > On Mon, Jan 20, 2014 at 04:39:45PM -0500, Len Brown wrote: > > > As a side note, at minimum the semantic and compatibility difference > > > needs to be _very_ clearly present in the naming. Something like > > > mwait_old_() or mwait_core2_(). That way such dependencies and > > > assumptions don't get lost in code restructuring, etc. > > > > Agreed. > > We started with mwait_idle() -- which was erroneously removed > > and is now being restored under it original name. > > > > The "new" function is mwait_idle_with_hints() -- which uses the > > additional hints that were not available w/ the original MWAIT > > instruction. Where "new" is Core Duo and later -- all the > > processor that can use MWAIT for C-states deeper than C1. > > I'm still waiting for someone to explain what's wrong with: > > static inline void mwait_idle(void) > { > local_irq_enable(); > mwait_idle_with_hints(0, 0); > } Absolutely agreed, we don't want to carry it on 'just because', the compatibility aspect needs to be documented - otherwise we degrade into cargo cult programming. Thanks, Ingo