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Commit 3edd4fc9 authored by Doug Doan's avatar Doug Doan Committed by Linus Torvalds
Browse files

hugetlb: call mmu notifiers on hugepage cow 



When a copy-on-write occurs, we take one of two paths in handle_mm_fault:
through handle_pte_fault for normal pages, or through hugetlb_fault for
huge pages.

In the normal page case, we eventually get to do_wp_page and call mmu
notifiers via ptep_clear_flush_notify.  There is no callout to the mmmu
notifiers in the huge page case.  This patch fixes that.

Signed-off-by: default avatarDoug Doan <dougd@cray.com>
Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a1b200e2

mm/hugetlb.c

+6 −0
Original line number Diff line number Diff line
@@ -2349,11 +2349,17 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 
	ptep = huge_pte_offset(mm, address & huge_page_mask(h));

	if (likely(pte_same(huge_ptep_get(ptep), pte))) {

		/* Break COW */

		mmu_notifier_invalidate_range_start(mm,

			address & huge_page_mask(h),

			(address & huge_page_mask(h)) + huge_page_size(h));

		huge_ptep_clear_flush(vma, address, ptep);

		set_huge_pte_at(mm, address, ptep,

				make_huge_pte(vma, new_page, 1));

		/* Make the old page be freed below */

		new_page = old_page;

		mmu_notifier_invalidate_range_end(mm,

			address & huge_page_mask(h),

			(address & huge_page_mask(h)) + huge_page_size(h));

	}

	page_cache_release(new_page);

	page_cache_release(old_page);