Messages in this thread | | | Date | Thu, 27 Apr 2006 23:27:04 -0700 | From | Chris Wright <> | Subject | Re: [PATCH] x86/PAE: Fix pte_clear for the >4GB RAM case |
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* Andi Kleen (ak@suse.de) wrote: > 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.
I must be confused. Doesn't that become a barrier() on UP? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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