[PATCH 07/11] mm/huge_memory: Fix can_split_huge_page assumption of THP size

Matthew Wilcox (Oracle)
2020-09-08T20:20:15Z

Ask the page how many subpages it has instead of assuming it's PMD size.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/huge_memory.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e9503b10df8f..8bf8caf66923 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2546,9 +2546,9 @@ bool can_split_huge_page(struct page *page, int *pextra_pins)

/* 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;
--
2.28.0