Commit bb373dce authored Dec 16, 2022 by Peter Xu Committed by Andrew Morton Jan 18, 2023

mm/hugetlb: don't wait for migration entry during follow page

That's what the code does with !hugetlb pages, so we should logically do
the same for hugetlb, so migration entry will also be treated as no page.

This is probably also the last piece in follow_page code that may sleep,
the last one should be removed in cf994dd8af27 ("mm/gup: remove
FOLL_MIGRATION", 2022-11-16).

Link: https://lkml.kernel.org/r/20221216155100.2043537-3-peterx@redhat.com


Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 243b1f2d

mm/hugetlb.c

+0 −11

Original line number	Diff line number	Diff line
		@@ -6401,7 +6401,6 @@ struct page hugetlb_follow_page_mask(struct vm_area_struct vma,
		if (WARN_ON_ONCE(flags & FOLL_PIN))
		return NULL;

		retry:
		pte = huge_pte_offset(mm, haddr, huge_page_size(h));
		if (!pte)
		return NULL;
		@@ -6424,16 +6423,6 @@ struct page hugetlb_follow_page_mask(struct vm_area_struct vma,
		page = NULL;
		goto out;
		}
		} else {
		if (is_hugetlb_entry_migration(entry)) {
		spin_unlock(ptl);
		__migration_entry_wait_huge(pte, ptl);
		goto retry;
		}
		/*
		* hwpoisoned entry is treated as no_page_table in
		* follow_page_mask().
		*/
		}
		out:
		spin_unlock(ptl);