[RFC PATCH 24/24] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page
From: Muchun Song <hidden>
Date: 2020-09-16 00:40:00
Also in:
linux-doc, linux-fsdevel, lkml
Subsystem:
hugetlb subsystem, memory management, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds
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 <redacted> --- mm/hugetlb.c | 2 ++ 1 file changed, 2 insertions(+)
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()) {
--
2.20.1