Commit 9818b8cd authored Jul 14, 2016 by Huang Ying Committed by Linus Torvalds Jul 15, 2016

madvise_free, thp: fix madvise_free_huge_pmd return value after splitting

madvise_free_huge_pmd should return 0 if the fallback PTE operations are
required.  In madvise_free_huge_pmd, if part pages of THP are discarded,
the THP will be split and fallback PTE operations should be used if
splitting succeeds.  But the original code will make fallback PTE
operations skipped, after splitting succeeds.  Fix that via make
madvise_free_huge_pmd return 0 after splitting successfully, so that the
fallback PTE operations will be done.

Link: http://lkml.kernel.org/r/1467135452-16688-1-git-send-email-ying.huang@intel.com


Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent ef722fd4

mm/huge_memory.c

+1 −6

Original line number	Diff line number	Diff line
		@@ -1624,16 +1624,11 @@ int madvise_free_huge_pmd(struct mmu_gather tlb, struct vm_area_struct vma,
		if (next - addr != HPAGE_PMD_SIZE) {
		get_page(page);
		spin_unlock(ptl);
		if (split_huge_page(page)) {
		split_huge_page(page);
		put_page(page);
		unlock_page(page);
		goto out_unlocked;
		}
		put_page(page);
		unlock_page(page);
		ret = 1;
		goto out_unlocked;
		}

		if (PageDirty(page))
		ClearPageDirty(page);

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