[PATCH 10/10] mm,hwpoison: Use hugetlb_replace_page to replace free hugetlb pages

From: Oscar Salvador
Date: Tue Sep 10 2019 - 06:31:09 EST


When soft offlining a free hugtlb, try first to allocate a new hugetlb
to the pool and pass the old state to the new one by move_hugetlb_state().
Either we succeed or not, we dissolve the poisoned hugetlb page.

Worst-scenario case is that we cannot allocate a new fresh hugetlb page
as a replacement.

Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
---
mm/hugetlb.c | 16 ++++++++++++++++
mm/memory-failure.c | 34 ++++++++++++++++++++++++++++------
2 files changed, 44 insertions(+), 6 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 139e1c05c9a1..d0844aec7531 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5154,3 +5154,19 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
spin_unlock(&hugetlb_lock);
}
}
+
+#ifdef CONFIG_MEMORY_FAILURE
+int hugetlb_replace_page(struct page *page, int reason)
+{
+ int nid = page_to_nid(page);
+ struct hstate *h = page_hstate(page);
+ struct page *new_page;
+
+ new_page = alloc_huge_page_nodemask(h, nid, &node_states[N_MEMORY]);
+ if (!new_page)
+ return -ENOMEM;
+
+ move_hugetlb_state(page, new_page, reason);
+ return 0;
+}
+#endif
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 03f07015a106..fe73fe19c6e9 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -79,6 +79,7 @@ EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask);
EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value);

extern bool take_page_off_buddy(struct page *page);
+extern int hugetlb_replace_page(struct page *page, int reason);

static bool page_set_poison(struct page *page)
{
@@ -1804,16 +1805,37 @@ static int soft_offline_in_use_page(struct page *page)
return __soft_offline_page(page);
}

+static int soft_offline_free_huge_page(struct page *page)
+{
+ struct page *hpage = compound_head(page);
+
+ /*
+ * Try to add a new hugetlb page to the pool
+ */
+ if (hugetlb_replace_page(hpage, MR_MEMORY_FAILURE))
+ return -EBUSY;
+
+ /*
+ * Remove old hugetlb from the pool
+ */
+ if (!page_set_poison(hpage))
+ return -EBUSY;
+
+ return 0;
+}
+
static int soft_offline_free_page(struct page *page)
{
- int rc = dissolve_free_huge_page(page);
+ int rc = -EBUSY;

- if (!rc) {
- if (take_page_off_buddy(page))
+ if (PageHuge(page))
+ rc = soft_offline_free_huge_page(page);
+ else
+ if (take_page_off_buddy(page)) {
page_set_poison(page);
- else
- rc = -EBUSY;
- }
+ rc = 0;
+ }
+
return rc;
}

--
2.12.3