diff mbox series

[RFC,24/24] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page

Message ID 20200915125947.26204-25-songmuchun@bytedance.com (mailing list archive)
State New, archived
Headers show
Series mm/hugetlb: Free some vmemmap pages of hugetlb page | expand

Commit Message

Muchun Song Sept. 15, 2020, 12:59 p.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.c | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e66c3f10c583..63995ba74b6b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3994,6 +3994,8 @@  static int __init hugetlb_init(void)
 
 #ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
 	BUILD_BUG_ON_NOT_POWER_OF_2(sizeof(struct page));
+	BUILD_BUG_ON(NR_USED_SUBPAGE >=
+		     RESERVE_VMEMMAP_SIZE / sizeof(struct page));
 #endif
 
 	if (!hugepages_supported()) {