On Fri 29-03-13 13:23:38, Naoya Horiguchi wrote: > Hi, > > On Fri, Mar 29, 2013 at 02:57:30PM +0100, Michal Hocko wrote: > > On Thu 28-03-13 11:42:38, Naoya Horiguchi wrote: > > [...] > > > @@ -2968,7 +2968,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, > > > * first, for the page indexing below to work. > > > */ > > > pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); > > > - absent = !pte || huge_pte_none(huge_ptep_get(pte)); > > > + absent = !pte || huge_pte_none(huge_ptep_get(pte)) || > > > + is_swap_pte(huge_ptep_get(pte)); > > > > is_swap_pte doesn't seem right. Shouldn't you use is_hugetlb_entry_hwpoisoned > > instead? > > I tested only hwpoisoned hugepage, but the same can happen for hugepages > under migration. So I intended to filter out all types of swap entries. > The local variable 'absent' seems to mean whether data on the address > is immediately available, so swap type entry isn't included in it. OK, I didn't consider huge pages under migration and I was merely worried that is_hugetlb_entry_hwpoisoned sounds more appropriate than is_swap_pte. Could you add a comment which would clarify that is_swap_pte covers both migration and hwpoison pages, please? Something like: /* * is_swap_pte test covers both is_hugetlb_entry_hwpoisoned * and hugepages under migration in which case * hugetlb_fault waits for the migration and bails out * properly for HWPosined pages. */ absent = !pte || huge_pte_none(huge_ptep_get(pte)) || is_swap_pte(huge_ptep_get(pte)); Other than that feel free to add Reviewed-by: Michal Hocko <mhocko@xxxxxxx> Thanks. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>