[PATCH v12 07/13] mm/hugetlb: Set the PageHWPoison to the raw error page

Muchun Song
2021-01-06T14:22:14Z

Because we reuse the first tail vmemmap page frame and remap it
with read-only, we cannot set the PageHWPosion on a tail page.
So we can use the head[4].private to record the real error page
index and set the raw error page PageHWPoison later.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
---
mm/hugetlb.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 61 insertions(+), 8 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d11c32fcdb38..6caaa7e5dd2a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1358,6 +1358,63 @@ static inline void __update_and_free_page(struct hstate *h, struct page *page)
schedule_work(&hpage_update_work);
}

+#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
+static inline void hwpoison_subpage_deliver(struct hstate *h, struct page *head)
+{
+ struct page *page;
+
+ if (!PageHWPoison(head) || !free_vmemmap_pages_per_hpage(h))
+ return;
+
+ page = head + page_private(head + 4);
+
+ /*
+ * Move PageHWPoison flag from head page to the raw error page,
+ * which makes any subpages rather than the error page reusable.
+ */
+ if (page != head) {
+ SetPageHWPoison(page);
+ ClearPageHWPoison(head);
+ }
+}
+
+static inline void hwpoison_subpage_set(struct hstate *h, struct page *head,
+ struct page *page)
+{
+ if (!PageHWPoison(head))
+ return;
+
+ if (free_vmemmap_pages_per_hpage(h)) {
+ set_page_private(head + 4, page - head);
+ } else if (page != head) {
+ /*
+ * Move PageHWPoison flag from head page to the raw error page,
+ * which makes any subpages rather than the error page reusable.
+ */
+ SetPageHWPoison(page);
+ ClearPageHWPoison(head);
+ }
+}
+
+#else
+static inline void hwpoison_subpage_deliver(struct hstate *h, struct page *head)
+{
+}
+
+static inline void hwpoison_subpage_set(struct hstate *h, struct page *head,
+ struct page *page)
+{
+ if (PageHWPoison(head) && page != head) {
+ /*
+ * Move PageHWPoison flag from head page to the raw error page,
+ * which makes any subpages rather than the error page reusable.
+ */
+ SetPageHWPoison(page);
+ ClearPageHWPoison(head);
+ }
+}
+#endif
+
static void update_and_free_page(struct hstate *h, struct page *page)
{
if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
@@ -1373,6 +1430,8 @@ static void __free_hugepage(struct hstate *h, struct page *page)
{
int i;

+ hwpoison_subpage_deliver(h, page);
+
for (i = 0; i < pages_per_huge_page(h); i++) {
page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
1 << PG_referenced | 1 << PG_dirty |
@@ -1845,14 +1904,8 @@ int dissolve_free_huge_page(struct page *page)
int nid = page_to_nid(head);
if (h->free_huge_pages - h->resv_huge_pages == 0)
goto out;
- /*
- * Move PageHWPoison flag from head page to the raw error page,
- * which makes any subpages rather than the error page reusable.
- */
- if (PageHWPoison(head) && page != head) {
- SetPageHWPoison(page);
- ClearPageHWPoison(head);
- }
+
+ hwpoison_subpage_set(h, head, page);
list_del(&head->lru);
h->free_huge_pages--;
h->free_huge_pages_node[nid]--;
--
2.11.0