diff mbox series

[v4,20/21] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page

Message ID 20201113105952.11638-21-songmuchun@bytedance.com (mailing list archive)
State New, archived
Headers show
Series Free some vmemmap pages of hugetlb page | expand

Commit Message

Muchun Song Nov. 13, 2020, 10:59 a.m. UTC 
There are only `RESERVE_VMEMMAP_SIZE / sizeof(struct page)` struct pages
can be used when CONFIG_HUGETLB_PAGE_FREE_VMEMMAP, so add a BUILD_BUG_ON
to catch this invalid usage of tail struct page.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 mm/hugetlb_vmemmap.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 5c00826a98b3..f67aec6e3bb1 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -717,6 +717,9 @@  static int __init vmemmap_ptlock_init(void)
 {
 	int nid;
 
+	BUILD_BUG_ON(NR_USED_SUBPAGE >=
+		     RESERVE_VMEMMAP_SIZE / sizeof(struct page));
+
 	if (!hugepages_supported())
 		return 0;