From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm/huge_memory: fix can_split_huge_page assumption of THP size Ask the page how many subpages it has instead of assuming it's PMD size. Link: https://lkml.kernel.org/r/20200908195539.25896-8-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Reviewed-by: SeongJae Park <sjpark@xxxxxxxxx> Acked-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/huge_memory.c~mm-huge_memory-fix-can_split_huge_page-assumption-of-thp-size +++ a/mm/huge_memory.c @@ -2582,9 +2582,9 @@ bool can_split_huge_page(struct page *pa /* Additional pins from page cache */ if (PageAnon(page)) - extra_pins = PageSwapCache(page) ? HPAGE_PMD_NR : 0; + extra_pins = PageSwapCache(page) ? thp_nr_pages(page) : 0; else - extra_pins = HPAGE_PMD_NR; + extra_pins = thp_nr_pages(page); if (pextra_pins) *pextra_pins = extra_pins; return total_mapcount(page) == page_count(page) - extra_pins - 1; _
