Date: Thu, 23 Jul 2015 16:58:01 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Jason Baron <jasonbaron0@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@amacapital.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Mikulas Patocka <mpatocka@redhat.com>,
        Paul Mackerras <paulus@samba.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Kees Cook <keescook@chromium.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Vince Weaver <vince@deater.net>, "hillf.zj" <hillf.zj@alibaba-inc.com>,
        Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>
Subject: Re: Kernel broken on processors without performance counters
Message-ID: <20150723145801.GI25159@twins.programming.kicks-ass.net>
References: <alpine.DEB.2.11.1507211726040.18576@nanos>
 <20150721154959.GS19282@twins.programming.kicks-ass.net>
 <CALCETrWwy777nYTVpOn8Hs1JRG5nDyvky9B11otDRAid1L19vg@mail.gmail.com>
 <20150721161215.GU19282@twins.programming.kicks-ass.net>
 <20150721181553.GA3378@nazgul.tnic>
 <55AE9471.1000601@gmail.com>
 <20150722042403.GA6345@nazgul.tnic>
 <55AFCDA4.5010406@gmail.com>
 <20150723104215.GH25159@twins.programming.kicks-ass.net>
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On Thu, Jul 23, 2015 at 10:19:52AM -0400, Jason Baron wrote:
> >
> > #define static_branch_likely(x)							\
> > ({										\
> > 	bool branch;								\
> > 	if (__builtin_types_compatible_p(typeof(x), struct static_key_true))	\
> > 		branch = !arch_static_branch(&(x)->key, false);			\
> > 	else if (__builtin_types_compatible_p(typeof(x), struct static_key_false)) \
> > 		branch = !arch_static_branch_jump(&(x)->key, true);		\
> > 	else									\
> > 		branch = ____wrong_branch_error();				\
> > 	branch;									\
> > })
> >
> > #define static_branch_unlikely(x)						\
> > ({										\
> > 	bool branch;								\
> > 	if (__builtin_types_compatible_p(typeof(x), struct static_key_true))	\
> > 		branch = arch_static_branch(&(x)->key, true);			\
> > 	else if (__builtin_types_compatible_p(typeof(x), struct static_key_false)) \
> > 		branch = arch_static_branch_jump(&(x)->key, false);		\
> > 	else									\
> > 		branch = ____wrong_branch_error();				\
> > 	branch;									\
> > })
> >
> 
> In 'static_branch_unlikely()', I think  arch_static_branch() and
> arch_static_branch_jump() are reversed.

Yes, you're right. But I think I need a nap before touching this stuff
again :-)

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