The patch titled
Subject: mm/hwpoison: check if a subpage of a hugetlb folio is raw HWPOISON
has been added to the -mm mm-unstable branch. Its filename is
mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Jiaqi Yan <jiaqiyan@xxxxxxxxxx>
Subject: mm/hwpoison: check if a subpage of a hugetlb folio is raw HWPOISON
Date: Fri, 7 Jul 2023 20:19:02 +0000
Add the functionality, is_raw_hwp_subpage, to tell if a subpage of a
hugetlb folio is a raw HWPOISON page. This functionality relies on
RawHwpUnreliable to be not set; otherwise hugepage's raw HWPOISON list
becomes meaningless.
is_raw_hwp_subpage needs to hold hugetlb_lock in order to synchronize with
__get_huge_page_for_hwpoison, who iterates and inserts an entry to
raw_hwp_list. llist itself doesn't ensure insertion is synchornized with
the iterating used by __is_raw_hwp_list. Caller can minimize the overhead
of lock cycles by first checking if folio / head page's HWPOISON flag is
set.
Exports this functionality to be immediately used in the read operation
for hugetlbfs.
Link: https://lkml.kernel.org/r/20230707201904.953262-3-jiaqiyan@xxxxxxxxxx
Signed-off-by: Jiaqi Yan <jiaqiyan@xxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: James Houghton <jthoughton@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 19 +++++++++++++++++++
include/linux/mm.h | 7 +++++++
mm/hugetlb.c | 10 ++++++++++
mm/memory-failure.c | 34 ++++++++++++++++++++++++----------
4 files changed, 60 insertions(+), 10 deletions(-)
--- a/include/linux/hugetlb.h~mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison
+++ a/include/linux/hugetlb.h
@@ -997,6 +997,25 @@ void hugetlb_register_node(struct node *
void hugetlb_unregister_node(struct node *node);
#endif
+/*
+ * Struct raw_hwp_page represents information about "raw error page",
+ * constructing singly linked list from ->_hugetlb_hwpoison field of folio.
+ */
+struct raw_hwp_page {
+ struct llist_node node;
+ struct page *page;
+};
+
+static inline struct llist_head *raw_hwp_list_head(struct folio *folio)
+{
+ return (struct llist_head *)&folio->_hugetlb_hwpoison;
+}
+
+/*
+ * Check if a given raw @subpage in a hugepage @folio is HWPOISON.
+ */
+bool is_raw_hwp_subpage(struct folio *folio, struct page *subpage);
+
#else /* CONFIG_HUGETLB_PAGE */
struct hstate {};
--- a/include/linux/mm.h~mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison
+++ a/include/linux/mm.h
@@ -3699,6 +3699,7 @@ extern const struct attribute_group memo
extern void memory_failure_queue(unsigned long pfn, int flags);
extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
bool *migratable_cleared);
+extern bool __is_raw_hwp_subpage(struct folio *folio, struct page *subpage);
void num_poisoned_pages_inc(unsigned long pfn);
void num_poisoned_pages_sub(unsigned long pfn, long i);
struct task_struct *task_early_kill(struct task_struct *tsk, int force_early);
@@ -3713,6 +3714,12 @@ static inline int __get_huge_page_for_hw
return 0;
}
+static inline bool __is_raw_hwp_subpage(struct folio *folio,
+ struct page *subpage)
+{
+ return false;
+}
+
static inline void num_poisoned_pages_inc(unsigned long pfn)
{
}
--- a/mm/hugetlb.c~mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison
+++ a/mm/hugetlb.c
@@ -7177,6 +7177,16 @@ int get_huge_page_for_hwpoison(unsigned
return ret;
}
+bool is_raw_hwp_subpage(struct folio *folio, struct page *subpage)
+{
+ bool ret;
+
+ spin_lock_irq(&hugetlb_lock);
+ ret = __is_raw_hwp_subpage(folio, subpage);
+ spin_unlock_irq(&hugetlb_lock);
+ return ret;
+}
+
void folio_putback_active_hugetlb(struct folio *folio)
{
spin_lock_irq(&hugetlb_lock);
--- a/mm/memory-failure.c~mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison
+++ a/mm/memory-failure.c
@@ -1808,18 +1808,32 @@ EXPORT_SYMBOL_GPL(mf_dax_kill_procs);
#endif /* CONFIG_FS_DAX */
#ifdef CONFIG_HUGETLB_PAGE
-/*
- * Struct raw_hwp_page represents information about "raw error page",
- * constructing singly linked list from ->_hugetlb_hwpoison field of folio.
- */
-struct raw_hwp_page {
- struct llist_node node;
- struct page *page;
-};
-static inline struct llist_head *raw_hwp_list_head(struct folio *folio)
+bool __is_raw_hwp_subpage(struct folio *folio, struct page *subpage)
{
- return (struct llist_head *)&folio->_hugetlb_hwpoison;
+ struct llist_head *raw_hwp_head;
+ struct raw_hwp_page *p, *tmp;
+ bool ret = false;
+
+ if (!folio_test_hwpoison(folio))
+ return false;
+
+ /*
+ * When RawHwpUnreliable is set, kernel lost track of which subpages
+ * are HWPOISON. So return as if ALL subpages are HWPOISONed.
+ */
+ if (folio_test_hugetlb_raw_hwp_unreliable(folio))
+ return true;
+
+ raw_hwp_head = raw_hwp_list_head(folio);
+ llist_for_each_entry_safe(p, tmp, raw_hwp_head->first, node) {
+ if (subpage == p->page) {
+ ret = true;
+ break;
+ }
+ }
+
+ return ret;
}
static unsigned long __folio_free_raw_hwp(struct folio *folio, bool move_flag)
_
Patches currently in -mm which might be from jiaqiyan@xxxxxxxxxx are
mm-hwpoison-delete-all-entries-before-traversal-in-__folio_free_raw_hwp.patch
mm-hwpoison-check-if-a-subpage-of-a-hugetlb-folio-is-raw-hwpoison.patch
hugetlbfs-improve-read-hwpoison-hugepage.patch
selftests-mm-add-tests-for-hwpoison-hugetlbfs-read.patch
