Re: [PATCH v2 12/20] mm, hugetlb: remove vma_has_reserves()

From: Joonsoo Kim
Date: Fri Aug 23 2013 - 02:16:48 EST


On Thu, Aug 22, 2013 at 04:34:22PM +0530, Aneesh Kumar K.V wrote:
> Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> writes:
>
> > On Thu, Aug 22, 2013 at 02:14:38PM +0530, Aneesh Kumar K.V wrote:
> >> Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> writes:
> >>
> >> > vma_has_reserves() can be substituted by using return value of
> >> > vma_needs_reservation(). If chg returned by vma_needs_reservation()
> >> > is 0, it means that vma has reserves. Otherwise, it means that vma don't
> >> > have reserves and need a hugepage outside of reserve pool. This definition
> >> > is perfectly same as vma_has_reserves(), so remove vma_has_reserves().
> >> >
> >> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> >>
> >> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> >
> > Thanks.
> >
> >> > @@ -580,8 +547,7 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
> >> > * have no page reserves. This check ensures that reservations are
> >> > * not "stolen". The child may still get SIGKILLed
> >> > */
> >> > - if (!vma_has_reserves(vma, chg) &&
> >> > - h->free_huge_pages - h->resv_huge_pages == 0)
> >> > + if (chg && h->free_huge_pages - h->resv_huge_pages == 0)
> >> > return NULL;
> >> >
> >> > /* If reserves cannot be used, ensure enough pages are in the pool */
> >> > @@ -600,7 +566,7 @@ retry_cpuset:
> >> > if (page) {
> >> > if (avoid_reserve)
> >> > break;
> >> > - if (!vma_has_reserves(vma, chg))
> >> > + if (chg)
> >> > break;
> >> >
> >> > SetPagePrivate(page);
> >>
> >> Can you add a comment above both the place to explain why checking chg
> >> is good enough ?
> >
> > Yes, I can. But it will be changed to use_reserve in patch 13 and it
> > represent it's meaning perfectly. So commeting may be useless.
>
> That should be ok, because having a comment in this patch helps in
> understanding the patch better, even though you are removing that
> later.

Okay. I will add it in next spin.

Thanks.
--
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/