Re: [PATCH v2 01/20] mm, hugetlb: protect reserved pages when softofflining a hugepage

[Davidlohr Bueso]

On Fri, 2013-08-09 at 18:26 +0900, Joonsoo Kim wrote:
> Don't use the reserve pool when soft offlining a hugepage.
> Check we have free pages outside the reserve pool before we
> dequeue the huge page. Otherwise, we can steal other's reserve page.
> 
> Reviewed-by: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>

Reviewed-by: Davidlohr Bueso <davidlohr@xxxxxx>

> 
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 6782b41..d971233 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -935,10 +935,11 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
>   */
>  struct page *alloc_huge_page_node(struct hstate *h, int nid)
>  {
> -	struct page *page;
> +	struct page *page = NULL;
>  
>  	spin_lock(&hugetlb_lock);
> -	page = dequeue_huge_page_node(h, nid);
> +	if (h->free_huge_pages - h->resv_huge_pages > 0)
> +		page = dequeue_huge_page_node(h, nid);
>  	spin_unlock(&hugetlb_lock);
>  
>  	if (!page)


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