1 files changed, 159 insertions, 87 deletions

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index a405d3dc0f61..26ca00c325d9 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -1,126 +1,198 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_MIGRATE_H
 #define _LINUX_MIGRATE_H
 
 #include <linux/mm.h>
 #include <linux/mempolicy.h>
 #include <linux/migrate_mode.h>
-
-typedef struct page *new_page_t(struct page *, unsigned long private, int **);
-
-/*
- * Return values from addresss_space_operations.migratepage():
- * - negative errno on page migration failure;
- * - zero on page migration success;
+#include <linux/hugetlb.h>
+
+typedef struct folio *new_folio_t(struct folio *folio, unsigned long private);
+typedef void free_folio_t(struct folio *folio, unsigned long private);
+
+struct migration_target_control;
+
+/**
+ * struct movable_operations - Driver page migration
+ * @isolate_page:
+ * The VM calls this function to prepare the page to be moved.  The page
+ * is locked and the driver should not unlock it.  The driver should
+ * return ``true`` if the page is movable and ``false`` if it is not
+ * currently movable.  After this function returns, the VM uses the
+ * page->lru field, so the driver must preserve any information which
+ * is usually stored here.
+ *
+ * @migrate_page:
+ * After isolation, the VM calls this function with the isolated
+ * @src page.  The driver should copy the contents of the
+ * @src page to the @dst page and set up the fields of @dst page.
+ * Both pages are locked.
+ * If page migration is successful, the driver should return 0.
+ * If the driver cannot migrate the page at the moment, it can return
+ * -EAGAIN.  The VM interprets this as a temporary migration failure and
+ * will retry it later.  Any other error value is a permanent migration
+ * failure and migration will not be retried.
+ * The driver shouldn't touch the @src->lru field while in the
+ * migrate_page() function.  It may write to @dst->lru.
  *
- * The balloon page migration introduces this special case where a 'distinct'
- * return code is used to flag a successful page migration to unmap_and_move().
- * This approach is necessary because page migration can race against balloon
- * deflation procedure, and for such case we could introduce a nasty page leak
- * if a successfully migrated balloon page gets released concurrently with
- * migration's unmap_and_move() wrap-up steps.
+ * @putback_page:
+ * If migration fails on the isolated page, the VM informs the driver
+ * that the page is no longer a candidate for migration by calling
+ * this function.  The driver should put the isolated page back into
+ * its own data structure.
  */
-#define MIGRATEPAGE_SUCCESS		0
-#define MIGRATEPAGE_BALLOON_SUCCESS	1 /* special ret code for balloon page
-					   * sucessful migration case.
-					   */
-enum migrate_reason {
-	MR_COMPACTION,
-	MR_MEMORY_FAILURE,
-	MR_MEMORY_HOTPLUG,
-	MR_SYSCALL,		/* also applies to cpusets */
-	MR_MEMPOLICY_MBIND,
-	MR_NUMA_MISPLACED,
-	MR_CMA
+struct movable_operations {
+	bool (*isolate_page)(struct page *, isolate_mode_t);
+	int (*migrate_page)(struct page *dst, struct page *src,
+			enum migrate_mode);
+	void (*putback_page)(struct page *);
 };
 
+/* Defined in mm/debug.c: */
+extern const char *migrate_reason_names[MR_TYPES];
+
 #ifdef CONFIG_MIGRATION
 
-extern void putback_lru_pages(struct list_head *l);
-extern void putback_movable_pages(struct list_head *l);
-extern int migrate_page(struct address_space *,
-			struct page *, struct page *, enum migrate_mode);
-extern int migrate_pages(struct list_head *l, new_page_t x,
-		unsigned long private, enum migrate_mode mode, int reason);
-extern int migrate_huge_page(struct page *, new_page_t x,
-		unsigned long private, enum migrate_mode mode);
-
-extern int fail_migrate_page(struct address_space *,
-			struct page *, struct page *);
-
-extern int migrate_prep(void);
-extern int migrate_prep_local(void);
-extern int migrate_vmas(struct mm_struct *mm,
-		const nodemask_t *from, const nodemask_t *to,
-		unsigned long flags);
-extern void migrate_page_copy(struct page *newpage, struct page *page);
-extern int migrate_huge_page_move_mapping(struct address_space *mapping,
-				  struct page *newpage, struct page *page);
+void putback_movable_pages(struct list_head *l);
+int migrate_folio(struct address_space *mapping, struct folio *dst,
+		struct folio *src, enum migrate_mode mode);
+int migrate_pages(struct list_head *l, new_folio_t new, free_folio_t free,
+		  unsigned long private, enum migrate_mode mode, int reason,
+		  unsigned int *ret_succeeded);
+struct folio *alloc_migration_target(struct folio *src, unsigned long private);
+bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode);
+bool isolate_folio_to_list(struct folio *folio, struct list_head *list);
+
+int migrate_huge_page_move_mapping(struct address_space *mapping,
+		struct folio *dst, struct folio *src);
+void migration_entry_wait_on_locked(softleaf_t entry, spinlock_t *ptl)
+		__releases(ptl);
+void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
+int folio_migrate_mapping(struct address_space *mapping,
+		struct folio *newfolio, struct folio *folio, int extra_count);
+int set_movable_ops(const struct movable_operations *ops, enum pagetype type);
+
 #else
 
-static inline void putback_lru_pages(struct list_head *l) {}
 static inline void putback_movable_pages(struct list_head *l) {}
-static inline int migrate_pages(struct list_head *l, new_page_t x,
-		unsigned long private, enum migrate_mode mode, int reason)
+static inline int migrate_pages(struct list_head *l, new_folio_t new,
+		free_folio_t free, unsigned long private,
+		enum migrate_mode mode, int reason, unsigned int *ret_succeeded)
 	{ return -ENOSYS; }
-static inline int migrate_huge_page(struct page *page, new_page_t x,
-		unsigned long private, enum migrate_mode mode)
-	{ return -ENOSYS; }
-
-static inline int migrate_prep(void) { return -ENOSYS; }
-static inline int migrate_prep_local(void) { return -ENOSYS; }
+static inline struct folio *alloc_migration_target(struct folio *src,
+		unsigned long private)
+	{ return NULL; }
+static inline bool isolate_movable_ops_page(struct page *page, isolate_mode_t mode)
+	{ return false; }
+static inline bool isolate_folio_to_list(struct folio *folio, struct list_head *list)
+	{ return false; }
 
-static inline int migrate_vmas(struct mm_struct *mm,
-		const nodemask_t *from, const nodemask_t *to,
-		unsigned long flags)
+static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
+				  struct folio *dst, struct folio *src)
 {
 	return -ENOSYS;
 }
-
-static inline void migrate_page_copy(struct page *newpage,
-				     struct page *page) {}
-
-static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
-				  struct page *newpage, struct page *page)
+static inline int set_movable_ops(const struct movable_operations *ops, enum pagetype type)
 {
 	return -ENOSYS;
 }
 
-/* Possible settings for the migrate_page() method in address_operations */
-#define migrate_page NULL
-#define fail_migrate_page NULL
-
 #endif /* CONFIG_MIGRATION */
 
 #ifdef CONFIG_NUMA_BALANCING
-extern int migrate_misplaced_page(struct page *page, int node);
-extern int migrate_misplaced_page(struct page *page, int node);
-extern bool migrate_ratelimited(int node);
+int migrate_misplaced_folio_prepare(struct folio *folio,
+		struct vm_area_struct *vma, int node);
+int migrate_misplaced_folio(struct folio *folio, int node);
 #else
-static inline int migrate_misplaced_page(struct page *page, int node)
+static inline int migrate_misplaced_folio_prepare(struct folio *folio,
+		struct vm_area_struct *vma, int node)
 {
 	return -EAGAIN; /* can't migrate now */
 }
-static inline bool migrate_ratelimited(int node)
+static inline int migrate_misplaced_folio(struct folio *folio, int node)
 {
-	return false;
+	return -EAGAIN; /* can't migrate now */
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
-#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
-extern int migrate_misplaced_transhuge_page(struct mm_struct *mm,
-			struct vm_area_struct *vma,
-			pmd_t *pmd, pmd_t entry,
-			unsigned long address,
-			struct page *page, int node);
-#else
-static inline int migrate_misplaced_transhuge_page(struct mm_struct *mm,
-			struct vm_area_struct *vma,
-			pmd_t *pmd, pmd_t entry,
-			unsigned long address,
-			struct page *page, int node)
+#ifdef CONFIG_MIGRATION
+
+/*
+ * Watch out for PAE architecture, which has an unsigned long, and might not
+ * have enough bits to store all physical address and flags. So far we have
+ * enough room for all our flags.
+ */
+#define MIGRATE_PFN_VALID	(1UL << 0)
+#define MIGRATE_PFN_MIGRATE	(1UL << 1)
+#define MIGRATE_PFN_WRITE	(1UL << 3)
+#define MIGRATE_PFN_COMPOUND	(1UL << 4)
+#define MIGRATE_PFN_SHIFT	6
+
+static inline struct page *migrate_pfn_to_page(unsigned long mpfn)
+{
+	if (!(mpfn & MIGRATE_PFN_VALID))
+		return NULL;
+	return pfn_to_page(mpfn >> MIGRATE_PFN_SHIFT);
+}
+
+static inline unsigned long migrate_pfn(unsigned long pfn)
 {
-	return -EAGAIN;
+	return (pfn << MIGRATE_PFN_SHIFT) | MIGRATE_PFN_VALID;
 }
-#endif /* CONFIG_NUMA_BALANCING && CONFIG_TRANSPARENT_HUGEPAGE*/
+
+enum migrate_vma_direction {
+	MIGRATE_VMA_SELECT_SYSTEM = 1 << 0,
+	MIGRATE_VMA_SELECT_DEVICE_PRIVATE = 1 << 1,
+	MIGRATE_VMA_SELECT_DEVICE_COHERENT = 1 << 2,
+	MIGRATE_VMA_SELECT_COMPOUND = 1 << 3,
+};
+
+struct migrate_vma {
+	struct vm_area_struct	*vma;
+	/*
+	 * Both src and dst array must be big enough for
+	 * (end - start) >> PAGE_SHIFT entries.
+	 *
+	 * The src array must not be modified by the caller after
+	 * migrate_vma_setup(), and must not change the dst array after
+	 * migrate_vma_pages() returns.
+	 */
+	unsigned long		*dst;
+	unsigned long		*src;
+	unsigned long		cpages;
+	unsigned long		npages;
+	unsigned long		start;
+	unsigned long		end;
+
+	/*
+	 * Set to the owner value also stored in page_pgmap(page)->owner
+	 * for migrating out of device private memory. The flags also need to
+	 * be set to MIGRATE_VMA_SELECT_DEVICE_PRIVATE.
+	 * The caller should always set this field when using mmu notifier
+	 * callbacks to avoid device MMU invalidations for device private
+	 * pages that are not being migrated.
+	 */
+	void			*pgmap_owner;
+	unsigned long		flags;
+
+	/*
+	 * Set to vmf->page if this is being called to migrate a page as part of
+	 * a migrate_to_ram() callback.
+	 */
+	struct page		*fault_page;
+};
+
+int migrate_vma_setup(struct migrate_vma *args);
+void migrate_vma_pages(struct migrate_vma *migrate);
+void migrate_vma_finalize(struct migrate_vma *migrate);
+int migrate_device_range(unsigned long *src_pfns, unsigned long start,
+			unsigned long npages);
+int migrate_device_pfns(unsigned long *src_pfns, unsigned long npages);
+void migrate_device_pages(unsigned long *src_pfns, unsigned long *dst_pfns,
+			unsigned long npages);
+void migrate_device_finalize(unsigned long *src_pfns,
+			unsigned long *dst_pfns, unsigned long npages);
+
+#endif /* CONFIG_MIGRATION */
 
 #endif /* _LINUX_MIGRATE_H */