Date: Tue, 21 Jan 2014 11:47:21 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Len Brown <lenb@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        linux-next@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: linux-next: build failure after merge of the tip tree
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* Peter Zijlstra <peterz@infradead.org> 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
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