Re: [PATCH 04/10] hugetlb: hugepage migration core

[Naoya Horiguchi]

On Mon, Sep 20, 2010 at 12:10:55PM +0100, Mel Gorman wrote:
> On Wed, Sep 08, 2010 at 10:19:35AM +0900, Naoya Horiguchi wrote:
...
> > @@ -95,26 +96,34 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
> >  	pte_t *ptep, pte;
> >   	spinlock_t *ptl;
> >  
> > - 	pgd = pgd_offset(mm, addr);
> > -	if (!pgd_present(*pgd))
> > -		goto out;
> > +	if (unlikely(PageHuge(new))) {
> > +		ptep = huge_pte_offset(mm, addr);
> > +		if (!ptep)
> > +			goto out;
> > +		ptl = &mm->page_table_lock;
> > +	} else {
> > +		pgd = pgd_offset(mm, addr);
> > +		if (!pgd_present(*pgd))
> > +			goto out;
> >  
> > -	pud = pud_offset(pgd, addr);
> > -	if (!pud_present(*pud))
> > -		goto out;
> > +		pud = pud_offset(pgd, addr);
> > +		if (!pud_present(*pud))
> > +			goto out;
> >  
> 
> Why are the changes to teh rest of the walkers necessary? Instead, why
> did you not identify which PTL lock you needed and then goto the point
> where spin_lock(ptl) is called? Similar to what page_check_address()
> does for example.

This is because Andi-san commented to avoid using goto sentense.
But honestly I'm not sure which is a clear way.

Thanks,
Naoya Horiguchi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/