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From: Marcel Moolenaar <marcel@xcllnt.net>
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Date: Thu, 24 May 2012 15:22:09 -0700
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To: Nathan Whitehorn <nwhitehorn@freebsd.org>
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Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org,
	Marcel Moolenaar <marcel@freebsd.org>, src-committers@freebsd.org
Subject: Re: svn commit: r235931 - head/sys/powerpc/include
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On May 24, 2012, at 3:15 PM, Nathan Whitehorn wrote:

>>> Summary:
>>> 1. *mb() must be lwsync or sync on all machines, except for wmb() =
which could be eieio
>>> 2. __ATOMIC_ACQ() must be isync (though could be reduced to lwsync =
with bus_space changes)
>>> 3. __ATOMIC_REL() must be lwsync or sync
>>=20
>> This is absolutely not what I concluded from our discussions. I have =
no idea
>> how we could end up so out of sync...
>>=20
>=20
> Thanks for the quick change. No idea how we got out of sync. I find =
all of this synchronization stuff a little mind-bending, so sorry for =
any miscommunication. __ATOMIC_ACQ() needed to also be isync on ppc64, =
so I've fixed that up. Things should be good now.

Ok. I didn't change wmb() to eieio as I wanted to avoid a pendulum =
effect.
I'll reread our emails and make sure wmb() is what we think it is and if
so I'll do a followup commit.
FYI,

--=20
Marcel Moolenaar
marcel@xcllnt.net