On Mon, Jul 29, 2013 at 03:24:46PM +0800, Hillf Danton wrote: > On Mon, Jul 29, 2013 at 1:31 PM, Joonsoo Kim <[email protected]> wrote: > > alloc_huge_page_node() use dequeue_huge_page_node() without > > any validation check, so it can steal reserved page unconditionally. > > Well, why is it illegal to use reserved page here?
Hello, Hillf. If we use reserved page here, other processes which are promised to use enough hugepages cannot get enough hugepages and can die. This is unexpected result to them. Thanks. > > > To fix it, check the number of free_huge_page in alloc_huge_page_node(). > > > > Signed-off-by: Joonsoo Kim <[email protected]> > > > > 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) > > -- > > 1.7.9.5 > > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to [email protected]. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"[email protected]";> [email protected] </a> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
