#ifdef CONFIG_MMU
+#ifdef CONFIG_SWAP
+#include <linux/swapfile.h>
+#endif /* CONFIG_SWAP */
+
/*
* swapcache pages are stored in the swapper_space radix tree. We want to
* get good packing density in that tree, so the index should be dense in
#define SWP_TYPE_SHIFT (BITS_PER_XA_VALUE - MAX_SWAPFILES_SHIFT)
#define SWP_OFFSET_MASK ((1UL << SWP_TYPE_SHIFT) - 1)
+/*
+ * Definitions only for PFN swap entries (see is_pfn_swap_entry()). To
+ * store PFN, we only need SWP_PFN_BITS bits. Each of the pfn swap entries
+ * can use the extra bits to store other information besides PFN.
+ */
+#ifdef MAX_PHYSMEM_BITS
+#define SWP_PFN_BITS (MAX_PHYSMEM_BITS - PAGE_SHIFT)
+#else /* MAX_PHYSMEM_BITS */
+#define SWP_PFN_BITS (BITS_PER_LONG - PAGE_SHIFT)
+#endif /* MAX_PHYSMEM_BITS */
+#define SWP_PFN_MASK (BIT(SWP_PFN_BITS) - 1)
+
+/**
+ * Migration swap entry specific bitfield definitions. Layout:
+ *
+ * |----------+--------------------|
+ * | swp_type | swp_offset |
+ * |----------+--------+-+-+-------|
+ * | | resv |D|A| PFN |
+ * |----------+--------+-+-+-------|
+ *
+ * @SWP_MIG_YOUNG_BIT: Whether the page used to have young bit set (bit A)
+ * @SWP_MIG_DIRTY_BIT: Whether the page used to have dirty bit set (bit D)
+ *
+ * Note: A/D bits will be stored in migration entries iff there're enough
+ * free bits in arch specific swp offset. By default we'll ignore A/D bits
+ * when migrating a page. Please refer to migration_entry_supports_ad()
+ * for more information. If there're more bits besides PFN and A/D bits,
+ * they should be reserved and always be zeros.
+ */
+#define SWP_MIG_YOUNG_BIT (SWP_PFN_BITS)
+#define SWP_MIG_DIRTY_BIT (SWP_PFN_BITS + 1)
+#define SWP_MIG_TOTAL_BITS (SWP_PFN_BITS + 2)
+
+#define SWP_MIG_YOUNG BIT(SWP_MIG_YOUNG_BIT)
+#define SWP_MIG_DIRTY BIT(SWP_MIG_DIRTY_BIT)
+
+static inline bool is_pfn_swap_entry(swp_entry_t entry);
+
/* Clear all flags but only keep swp_entry_t related information */
static inline pte_t pte_swp_clear_flags(pte_t pte)
{
return entry.val & SWP_OFFSET_MASK;
}
+/*
+ * This should only be called upon a pfn swap entry to get the PFN stored
+ * in the swap entry. Please refers to is_pfn_swap_entry() for definition
+ * of pfn swap entry.
+ */
+static inline unsigned long swp_offset_pfn(swp_entry_t entry)
+{
+ VM_BUG_ON(!is_pfn_swap_entry(entry));
+ return swp_offset(entry) & SWP_PFN_MASK;
+}
+
/* check whether a pte points to a swap entry */
static inline int is_swap_pte(pte_t pte)
{
return swp_entry(SWP_MIGRATION_WRITE, offset);
}
+/*
+ * Returns whether the host has large enough swap offset field to support
+ * carrying over pgtable A/D bits for page migrations. The result is
+ * pretty much arch specific.
+ */
+static inline bool migration_entry_supports_ad(void)
+{
+#ifdef CONFIG_SWAP
+ return swap_migration_ad_supported;
+#else /* CONFIG_SWAP */
+ return false;
+#endif /* CONFIG_SWAP */
+}
+
+static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
+{
+ if (migration_entry_supports_ad())
+ return swp_entry(swp_type(entry),
+ swp_offset(entry) | SWP_MIG_YOUNG);
+ return entry;
+}
+
+static inline bool is_migration_entry_young(swp_entry_t entry)
+{
+ if (migration_entry_supports_ad())
+ return swp_offset(entry) & SWP_MIG_YOUNG;
+ /* Keep the old behavior of aging page after migration */
+ return false;
+}
+
+static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
+{
+ if (migration_entry_supports_ad())
+ return swp_entry(swp_type(entry),
+ swp_offset(entry) | SWP_MIG_DIRTY);
+ return entry;
+}
+
+static inline bool is_migration_entry_dirty(swp_entry_t entry)
+{
+ if (migration_entry_supports_ad())
+ return swp_offset(entry) & SWP_MIG_DIRTY;
+ /* Keep the old behavior of clean page after migration */
+ return false;
+}
+
extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
spinlock_t *ptl);
extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
#ifdef CONFIG_HUGETLB_PAGE
extern void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl);
extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
-#endif
-#else
+#endif /* CONFIG_HUGETLB_PAGE */
+#else /* CONFIG_MIGRATION */
static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
{
return swp_entry(0, 0);
#ifdef CONFIG_HUGETLB_PAGE
static inline void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) { }
static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { }
-#endif
+#endif /* CONFIG_HUGETLB_PAGE */
static inline int is_writable_migration_entry(swp_entry_t entry)
{
return 0;
return 0;
}
-#endif
+static inline swp_entry_t make_migration_entry_young(swp_entry_t entry)
+{
+ return entry;
+}
+
+static inline bool is_migration_entry_young(swp_entry_t entry)
+{
+ return false;
+}
+
+static inline swp_entry_t make_migration_entry_dirty(swp_entry_t entry)
+{
+ return entry;
+}
+
+static inline bool is_migration_entry_dirty(swp_entry_t entry)
+{
+ return false;
+}
+#endif /* CONFIG_MIGRATION */
typedef unsigned long pte_marker;
static inline struct page *pfn_swap_entry_to_page(swp_entry_t entry)
{
- struct page *p = pfn_to_page(swp_offset(entry));
+ struct page *p = pfn_to_page(swp_offset_pfn(entry));
/*
* Any use of migration entries may only occur while the
*/
static inline bool is_pfn_swap_entry(swp_entry_t entry)
{
+ /* Make sure the swp offset can always store the needed fields */
+ BUILD_BUG_ON(SWP_TYPE_SHIFT < SWP_PFN_BITS);
+
return is_migration_entry(entry) || is_device_private_entry(entry) ||
is_device_exclusive_entry(entry);
}
{
return is_swap_pmd(pmd) && is_migration_entry(pmd_to_swp_entry(pmd));
}
-#else
+#else /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
static inline int set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
struct page *page)
{
{
return 0;
}
-#endif
+#endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
#ifdef CONFIG_MEMORY_FAILURE
return swp_type(entry) == SWP_HWPOISON;
}
-static inline unsigned long hwpoison_entry_to_pfn(swp_entry_t entry)
-{
- return swp_offset(entry);
-}
-
static inline void num_poisoned_pages_inc(void)
{
atomic_long_inc(&num_poisoned_pages);
}
-static inline void num_poisoned_pages_dec(void)
-{
- atomic_long_dec(&num_poisoned_pages);
-}
-
static inline void num_poisoned_pages_sub(long i)
{
atomic_long_sub(i, &num_poisoned_pages);
}
-#else
+#else /* CONFIG_MEMORY_FAILURE */
static inline swp_entry_t make_hwpoison_entry(struct page *page)
{
static inline void num_poisoned_pages_sub(long i)
{
}
-#endif
+#endif /* CONFIG_MEMORY_FAILURE */
static inline int non_swap_entry(swp_entry_t entry)
{
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