1 files changed, 152 insertions, 0 deletions
diff --git a/include/linux/page_idle.h b/include/linux/page_idle.h
new file mode 100644
index 000000000..5cb7bd207
--- /dev/null
+++ b/include/linux/page_idle.h
@@ -0,0 +1,152 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_MM_PAGE_IDLE_H
+#define _LINUX_MM_PAGE_IDLE_H
+
+#include <linux/bitops.h>
+#include <linux/page-flags.h>
+#include <linux/page_ext.h>
+
+#ifdef CONFIG_PAGE_IDLE_FLAG
+
+#ifndef CONFIG_64BIT
+/*
+ * If there is not enough space to store Idle and Young bits in page flags, use
+ * page ext flags instead.
+ */
+static inline bool folio_test_young(struct folio *folio)
+{
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+	bool page_young;
+
+	if (unlikely(!page_ext))
+		return false;
+
+	page_young = test_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_ext_put(page_ext);
+
+	return page_young;
+}
+
+static inline void folio_set_young(struct folio *folio)
+{
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+
+	if (unlikely(!page_ext))
+		return;
+
+	set_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_ext_put(page_ext);
+}
+
+static inline bool folio_test_clear_young(struct folio *folio)
+{
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+	bool page_young;
+
+	if (unlikely(!page_ext))
+		return false;
+
+	page_young = test_and_clear_bit(PAGE_EXT_YOUNG, &page_ext->flags);
+	page_ext_put(page_ext);
+
+	return page_young;
+}
+
+static inline bool folio_test_idle(struct folio *folio)
+{
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+	bool page_idle;
+
+	if (unlikely(!page_ext))
+		return false;
+
+	page_idle =  test_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_ext_put(page_ext);
+
+	return page_idle;
+}
+
+static inline void folio_set_idle(struct folio *folio)
+{
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+
+	if (unlikely(!page_ext))
+		return;
+
+	set_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_ext_put(page_ext);
+}
+
+static inline void folio_clear_idle(struct folio *folio)
+{
+	struct page_ext *page_ext = page_ext_get(&folio->page);
+
+	if (unlikely(!page_ext))
+		return;
+
+	clear_bit(PAGE_EXT_IDLE, &page_ext->flags);
+	page_ext_put(page_ext);
+}
+#endif /* !CONFIG_64BIT */
+
+#else /* !CONFIG_PAGE_IDLE_FLAG */
+
+static inline bool folio_test_young(struct folio *folio)
+{
+	return false;
+}
+
+static inline void folio_set_young(struct folio *folio)
+{
+}
+
+static inline bool folio_test_clear_young(struct folio *folio)
+{
+	return false;
+}
+
+static inline bool folio_test_idle(struct folio *folio)
+{
+	return false;
+}
+
+static inline void folio_set_idle(struct folio *folio)
+{
+}
+
+static inline void folio_clear_idle(struct folio *folio)
+{
+}
+
+#endif /* CONFIG_PAGE_IDLE_FLAG */
+
+static inline bool page_is_young(struct page *page)
+{
+	return folio_test_young(page_folio(page));
+}
+
+static inline void set_page_young(struct page *page)
+{
+	folio_set_young(page_folio(page));
+}
+
+static inline bool test_and_clear_page_young(struct page *page)
+{
+	return folio_test_clear_young(page_folio(page));
+}
+
+static inline bool page_is_idle(struct page *page)
+{
+	return folio_test_idle(page_folio(page));
+}
+
+static inline void set_page_idle(struct page *page)
+{
+	folio_set_idle(page_folio(page));
+}
+
+static inline void clear_page_idle(struct page *page)
+{
+	folio_clear_idle(page_folio(page));
+}
+#endif /* _LINUX_MM_PAGE_IDLE_H */