Messages in this thread Patch in this message | | | Date | Mon, 4 Aug 2014 11:29:00 -0400 | From | Naoya Horiguchi <> | Subject | Re: [PATCH v2 1/3] mm/hugetlb: take refcount under page table lock in follow_huge_pmd() |
| |
On Fri, Aug 01, 2014 at 02:53:58PM -0700, Andrew Morton wrote: ... > > --- mmotm-2014-07-22-15-58.orig/mm/hugetlb.c > > +++ mmotm-2014-07-22-15-58/mm/hugetlb.c > > @@ -3687,6 +3687,33 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address, > > > > #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ > > > > +struct page *follow_huge_pmd_lock(struct vm_area_struct *vma, > > + unsigned long address, pmd_t *pmd, int flags) > > Some documentation here wouldn't hurt. Why it exists, what it does. > And especially: any preconditions to calling it (ie: locking).
Sorry, I missed this comment. How about this?
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 1da7ca2e2a02..923465c0b47f 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3693,6 +3693,14 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address, #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ +/* + * This function calls the architecture dependent variant follow_huge_pmd() + * with holding page table lock depending on FOLL_GET. + * Whether hugepage migration is supported or not, follow() can be called + * with FOLL_GET from do_move_page_to_node_array(), so we need do this in + * common code. + * Should be called under read mmap_sem. + */ struct page *follow_huge_pmd_lock(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd, int flags) {
| |