From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH v2 0/3] x86: faster mb()+other barrier.h tweaks
Date: Wed, 27 Jan 2016 16:18:45 +0200
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To: Peter Zijlstra <peterz@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>, Davidlohr Bueso <dbueso@suse.de>, the arch/x86 maintainers <x86@kernel.org>, linux-kernel@vger.kernel.org, virtualization <virtualization@lists.linux-foundation.org>, Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Linus Torvalds <torvalds@linux-foundation.org>, Ingo Molnar <mingo@kernel.org>
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On Wed, Jan 27, 2016 at 03:14:09PM +0100, Peter Zijlstra wrote:
> On Wed, Jan 27, 2016 at 04:07:56PM +0200, Michael S. Tsirkin wrote:
> > mwait_idle is the only one that calls smp_mb and not mb()
> > I couldn't figure out why - original patches did mb()
> > there.
> 
> That probably wants changing. That said, running UP kernels on affected
> hardware is 'unlikely' :-)

OK that's nice. After changing that one place, everyone calls
mb() around clflush so it should be safe to change smp_mb away
from mfence without breaking things.
I'm testing v4 that does this.

-- 
MST