From 86b562b629728a072e6928bdc02a105d358a007d Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 15 Oct 2020 20:05:33 -0700 Subject: [PATCH] mm/huge_memory: fix total_mapcount assumption of page size File THPs may now be of arbitrary order. Signed-off-by: Kirill A. Shutemov Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: SeongJae Park Cc: Huang Ying Link: https://lkml.kernel.org/r/20200908195539.25896-5-willy@infradead.org Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index aa612cc5b3fe..b63c98516a7c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2494,7 +2494,7 @@ static void __split_huge_page(struct page *page, struct list_head *list, int total_mapcount(struct page *page) { - int i, compound, ret; + int i, compound, nr, ret; VM_BUG_ON_PAGE(PageTail(page), page); @@ -2502,16 +2502,17 @@ int total_mapcount(struct page *page) return atomic_read(&page->_mapcount) + 1; compound = compound_mapcount(page); + nr = compound_nr(page); if (PageHuge(page)) return compound; ret = compound; - for (i = 0; i < HPAGE_PMD_NR; i++) + for (i = 0; i < nr; i++) ret += atomic_read(&page[i]._mapcount) + 1; /* File pages has compound_mapcount included in _mapcount */ if (!PageAnon(page)) - return ret - compound * HPAGE_PMD_NR; + return ret - compound * nr; if (PageDoubleMap(page)) - ret -= HPAGE_PMD_NR; + ret -= nr; return ret; }