Re: [PATCH] Don't touch single threaded PTEs which are on the right node

[Andi Kleen]

> >  	do {
> >  		oldpte = *pte;
> > @@ -94,6 +100,13 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
> >  				/* Avoid TLB flush if possible */
> >  				if (pte_protnone(oldpte))
> >  					continue;
> > +
> > +				/*
> > +				 * Don't mess with PTEs if page is already on the node
> > +				 * a single-threaded process is running on.
> > +				 */
> > +				if (target_node == page_to_nid(page))
> > +					continue;
> >  			}
> >  
> 
> Check target_node != NUMA_NODE && target_node == page_to_nid(page) to
> avoid unnecessary page->flag masking and shifts?

I didn't do this last change because I expect a potentially mispredicted
check is more expensive than some shifting/masking.

-Andi