From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Add a new compound_lock() needed to serialize put_page against
__split_huge_page_refcount().
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>
---
include/linux/mm.h | 15 +++++++++++++++
include/linux/page-flags.h | 12 +++++++++++-
2 files changed, 26 insertions(+), 1 deletion(-)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -13,6 +13,7 @@
#include <linux/debug_locks.h>
#include <linux/mm_types.h>
#include <linux/range.h>
+#include <linux/bit_spinlock.h>
struct mempolicy;
struct anon_vma;
@@ -297,6 +298,20 @@ static inline int is_vmalloc_or_module_a
}
#endif
+static inline void compound_lock(struct page *page)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ bit_spin_lock(PG_compound_lock, &page->flags);
+#endif
+}
+
+static inline void compound_unlock(struct page *page)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ bit_spin_unlock(PG_compound_lock, &page->flags);
+#endif
+}
+
static inline struct page *compound_head(struct page *page)
{
if (unlikely(PageTail(page)))
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -108,6 +108,9 @@ enum pageflags {
#ifdef CONFIG_MEMORY_FAILURE
PG_hwpoison, /* hardware poisoned page. Don't touch */
#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ PG_compound_lock,
+#endif
__NR_PAGEFLAGS,
/* Filesystems */
@@ -399,6 +402,12 @@ static inline void __ClearPageTail(struc
#define __PG_MLOCKED 0
#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+#define __PG_COMPOUND_LOCK (1 << PG_compound_lock)
+#else
+#define __PG_COMPOUND_LOCK 0
+#endif
+
/*
* Flags checked when a page is freed. Pages being freed should not have
* these flags set. It they are, there is a problem.
@@ -408,7 +417,8 @@ static inline void __ClearPageTail(struc
1 << PG_private | 1 << PG_private_2 | \
1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
- 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON)
+ 1 << PG_unevictable | __PG_MLOCKED | __PG_HWPOISON | \
+ __PG_COMPOUND_LOCK)
/*
* Flags checked when a page is prepped for return by the page allocator.
--
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