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Re: [PATCH v4 5/5] x86: drop mfence in favor of lock+addl

From	"Michael S. Tsirkin" <mst@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4 5/5] x86: drop mfence in favor of lock+addl
Date	2016-01-27 19:00 +0100
Message-ID	<qVCxR-7c1-31@gated-at.bofh.it> (permalink)
References	<qVA30-5qa-11@gated-at.bofh.it> <qVA31-5qa-25@gated-at.bofh.it> <qVCev-72J-33@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Jan 27, 2016 at 09:37:45AM -0800, Linus Torvalds wrote:
> On Wed, Jan 27, 2016 at 7:10 AM, Michael S. Tsirkin <mst@redhat.com> wrote:
> >
> > -#define __smp_mb()     mb()
> > +#define __smp_mb()     asm volatile("lock; addl $0,-4(%%esp)" ::: "memory", "cc")
> 
> So this doesn't look right for x86-64. Using %esp rather than %rsp.
> How did that even work for you?
> 
>                 Linus

Oops, didn't test this version properly.
Pls disregard, I'll repost after some proper testing.

-- 
MST

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[PATCH v4 5/5] x86: drop mfence in favor of lock+addl "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-27 16:20 +0100
  Re: [PATCH v4 5/5] x86: drop mfence in favor of lock+addl Linus Torvalds <torvalds@linux-foundation.org> - 2016-01-27 18:40 +0100
    Re: [PATCH v4 5/5] x86: drop mfence in favor of lock+addl "Michael S. Tsirkin" <mst@redhat.com> - 2016-01-27 19:00 +0100

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