On Wed 17-03-21 12:12:50, Oscar Salvador wrote:
> alloc_contig_range() will fail if it finds a HugeTLB page within the range,
> without a chance to handle them. Since HugeTLB pages can be migrated as any
> LRU or Movable page, it does not make sense to bail out without trying.
> Enable the interface to recognize in-use HugeTLB pages so we can migrate
> them, and have much better chances to succeed the call.
>
> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
I am still not entirely happy about this
> @@ -2347,7 +2351,19 @@ int isolate_or_dissolve_huge_page(struct page *page)
> if (hstate_is_gigantic(h))
> return -ENOMEM;
>
> - return alloc_and_dissolve_huge_page(h, head);
> +retry:
> + if (page_count(head) && isolate_huge_page(head, list)) {
> + ret = 0;
> + } else if (!page_count(head)) {
> + ret = alloc_and_dissolve_huge_page(h, head);
> +
> + if (ret == -EBUSY && try_again) {
> + try_again = false;
> + goto retry;
> + }
> + }
> +
> + return ret;
> }
it would be imho better to retry inside alloc_and_dissolve_huge_page
because it already has its retry logic implemented.
But not something I will insist on.
--
Michal Hocko
SUSE Labs
