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Date: Thu, 27 Apr 2006 22:23:28 -0700
From: Chris Wright <chrisw@sous-sol.org>
To: Andi Kleen <ak@suse.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, zach@vmware.com,
       torvalds@osdl.org
Subject: Re: [PATCH] x86/PAE: Fix pte_clear for the >4GB RAM case
Message-ID: <20060428052328.GA4409@sorel.sous-sol.org>
References: <200604272001.k3RK1dmX007637@hera.kernel.org> <p73mze66zx8.fsf@bragg.suse.de>
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* Andi Kleen (ak@suse.de) wrote:
> > +static inline void pmd_clear(pmd_t *pmd)
> > +{
> > +	u32 *tmp = (u32 *)pmd;
> > +	*tmp = 0;
> > +	smp_wmb();
> > +	*(tmp + 1) = 0;
> > +}
> 
> I think that's still wrong - it should be wmb() not smp_wmb because this
> problem can happen on a UP kernel already.

I thought the barrier is to keep compiler from reordering not processor.