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Date: Thu, 28 May 2020 19:58:11 -0700 From: Matthew Wilcox <willy@...radead.org> To: linux-fsdevel@...r.kernel.org Cc: "Kirill A. Shutemov" <kirill@...temov.name>, linux-mm@...ck.org, linux-kernel@...r.kernel.org, Matthew Wilcox <willy@...radead.org> Subject: [PATCH v5 26/39] mm: Fix total_mapcount assumption of page size From: "Kirill A. Shutemov" <kirill@...temov.name> File THPs may now be of arbitrary order. Signed-off-by: Kirill A. Shutemov <kirill@...temov.name> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org> --- 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 7a5e2b470bc7..15a86b06befc 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2668,7 +2668,7 @@ 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); @@ -2676,16 +2676,17 @@ 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; } -- 2.26.2
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