Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH] x86/PAE: Fix pte_clear for the >4GB RAM case | Date | Fri, 28 Apr 2006 08:08:44 +0200 |
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On Friday 28 April 2006 07:23, Chris Wright wrote: > * 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.
Yes, but with smp_wmb() it will go away on UP. And even on UP the CPU is free to speculate.
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