[PATCH v4 21/21] mm/hugetlb: Disable freeing vmemmap if struct page size is not power of two

[Muchun Song]

We only can free the unused vmemmap to the buddy system when the
size of struct page is a power of two.

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
 mm/hugetlb_vmemmap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index f67aec6e3bb1..a0a5df9dba6b 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -635,7 +635,8 @@ void __init hugetlb_vmemmap_init(struct hstate *h)
 	unsigned int order = huge_page_order(h);
 	unsigned int vmemmap_pages;
 
-	if (hugetlb_free_vmemmap_disabled) {
+	if (hugetlb_free_vmemmap_disabled ||
+	    !is_power_of_2(sizeof(struct page))) {
 		h->nr_free_vmemmap_pages = 0;
 		pr_info("disable free vmemmap pages for %s\n", h->name);
 		return;
-- 
2.11.0