Because we reuse the first tail vmemmap page frame and remap it
with read-only, we cannot set the PageHWPosion on some tail pages.
So we can use the head[4].private (There are at least 128 struct
page structures associated with the optimized HugeTLB page, so
using head[4].private is safe) to record the real error page index
and set the raw error page PageHWPoison later.
We cannot have more poisoned tail pages. So a single slot is
sufficient. Why?
memory_failure()
if (PageHuge(page))
memory_failure_hugetlb()
head = compound_head(page)
if (TestSetPageHWPoison(head))
return
Because we do not clear the HWPoison of the head page, we cannot
poison another tail page.
Note: some pages might miss their poisoning (even without this patch).
Signed-off-by: Muchun Song <[email protected]>
Reviewed-by: Oscar Salvador <[email protected]>
Acked-by: David Rientjes <[email protected]>
Tested-by: Chen Huang <[email protected]>
Tested-by: Bodeddula Balasubramaniam <[email protected]>
---
include/linux/hugetlb.h | 3 ++
mm/hugetlb.c | 81 +++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 75 insertions(+), 9 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 09421f5f35e2..7f7a0e3405ae 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -42,6 +42,9 @@ enum {
SUBPAGE_INDEX_CGROUP_RSVD, /* reuse page->private */
__MAX_CGROUP_SUBPAGE_INDEX = SUBPAGE_INDEX_CGROUP_RSVD,
#endif
+#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP
+ SUBPAGE_INDEX_HWPOISON, /* reuse page->private */
+#endif
__NR_USED_SUBPAGE,
};
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e42b19337a8f..53f239818293 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1304,6 +1304,74 @@ static inline void destroy_compound_gigantic_page(struct
page *page,
unsigned int order) { }
#endif
+#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 + SUBPAGE_INDEX_HWPOISON);
+
+ /*
+ * 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 + SUBPAGE_INDEX_HWPOISON, 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);
+ }
+}
+
+static inline void hwpoison_subpage_clear(struct hstate *h, struct page *head)
+{
+ if (!PageHWPoison(head) || !free_vmemmap_pages_per_hpage(h))
+ return;
+
+ set_page_private(head + SUBPAGE_INDEX_HWPOISON, 0);
+}
+#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);
+ }
+}
+
+static inline void hwpoison_subpage_clear(struct hstate *h, struct page *head)
+{
+}
+#endif
+
static int update_and_free_page_surplus(struct hstate *h, struct page *page,
bool acct_surplus)
__releases(&hugetlb_lock) __acquires(&hugetlb_lock)
@@ -1807,22 +1875,17 @@ int dissolve_free_huge_page(struct page *page)
goto retry;
}
- /*
- * 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);
ClearHPageFreed(page);
h->free_huge_pages--;
h->free_huge_pages_node[nid]--;
h->max_huge_pages--;
rc = update_and_free_page_surplus(h, head, false);
- if (rc)
+ if (rc) {
h->max_huge_pages++;
+ hwpoison_subpage_clear(h, head);
+ }
}
out:
spin_unlock(&hugetlb_lock);
--
2.11.0
