diff mbox series

[v7,15/15] mm/hugetlb: Add BUILD_BUG_ON to catch invalid usage of tail struct page

Message ID 20201130151838.11208-16-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. 30, 2020, 3:18 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_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 ebc710d148e4..3328de88819e 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -340,6 +340,9 @@  void __init hugetlb_vmemmap_init(struct hstate *h)
 	unsigned int nr_pages = pages_per_huge_page(h);
 	unsigned int vmemmap_pages;
 
+	BUILD_BUG_ON(NR_USED_SUBPAGE >=
+		     RESERVE_VMEMMAP_SIZE / sizeof(struct page));
+
 	if (!is_power_of_2(sizeof(struct page)) ||
 	    !hugetlb_free_vmemmap_enabled) {
 		pr_info("disable freeing vmemmap pages for %s\n", h->name);