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.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: SeongJae Park <sjpark@amazon.de>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: "Huang, Ying" <ying.huang@intel.com>
Link: https://lkml.kernel.org/r/20200908195539.25896-8-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-10-15 20:05:43 -07:00 committed by Linus Torvalds
parent 65dfe3c3bc
commit e2333dad2d

View file

@ -2582,9 +2582,9 @@ 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;