include/linux/huge_mm.h

   1 #ifndef _LINUX_HUGE_MM_H
   2 #define _LINUX_HUGE_MM_H
   3
   4 extern int do_huge_pmd_anonymous_page(struct mm_struct *mm,
   5                                       struct vm_area_struct *vma,
   6                                       unsigned long address, pmd_t *pmd,
   7                                       unsigned int flags);
   8 extern int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
   9                          pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
  10                          struct vm_area_struct *vma);
  11 extern void huge_pmd_set_accessed(struct mm_struct *mm,
  12                                   struct vm_area_struct *vma,
  13                                   unsigned long address, pmd_t *pmd,
  14                                   pmd_t orig_pmd, int dirty);
  15 extern int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
  16                                unsigned long address, pmd_t *pmd,
  17                                pmd_t orig_pmd);
  18 extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
  19                                           unsigned long addr,
  20                                           pmd_t *pmd,
  21                                           unsigned int flags);
  22 extern int zap_huge_pmd(struct mmu_gather *tlb,
  23                         struct vm_area_struct *vma,
  24                         pmd_t *pmd, unsigned long addr);
  25 extern int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
  26                         unsigned long addr, unsigned long end,
  27                         unsigned char *vec);
  28 extern int move_huge_pmd(struct vm_area_struct *vma,
  29                          struct vm_area_struct *new_vma,
  30                          unsigned long old_addr,
  31                          unsigned long new_addr, unsigned long old_end,
  32                          pmd_t *old_pmd, pmd_t *new_pmd);
  33 extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
  34                         unsigned long addr, pgprot_t newprot,
  35                         int prot_numa);
  36
  37 enum transparent_hugepage_flag {
  38         TRANSPARENT_HUGEPAGE_FLAG,
  39         TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
  40         TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
  41         TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
  42         TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG,
  43         TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG,
  44 #ifdef CONFIG_DEBUG_VM
  45         TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG,
  46 #endif
  47 };
  48
  49 enum page_check_address_pmd_flag {
  50         PAGE_CHECK_ADDRESS_PMD_FLAG,
  51         PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG,
  52         PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG,
  53 };
  54 extern pmd_t *page_check_address_pmd(struct page *page,
  55                                      struct mm_struct *mm,
  56                                      unsigned long address,
  57                                      enum page_check_address_pmd_flag flag,
  58                                      spinlock_t **ptl);
  59
  60 #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
  61 #define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
  62
  63 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  64 #define HPAGE_PMD_SHIFT PMD_SHIFT
  65 #define HPAGE_PMD_SIZE  ((1UL) << HPAGE_PMD_SHIFT)
  66 #define HPAGE_PMD_MASK  (~(HPAGE_PMD_SIZE - 1))
  67
  68 extern bool is_vma_temporary_stack(struct vm_area_struct *vma);
  69
  70 #define transparent_hugepage_enabled(__vma)                             \
  71         ((transparent_hugepage_flags &                                  \
  72           (1<<TRANSPARENT_HUGEPAGE_FLAG) ||                             \
  73           (transparent_hugepage_flags &                                 \
  74            (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG) &&                   \
  75            ((__vma)->vm_flags & VM_HUGEPAGE))) &&                       \
  76          !((__vma)->vm_flags & VM_NOHUGEPAGE) &&                        \
  77          !is_vma_temporary_stack(__vma))
  78 #define transparent_hugepage_defrag(__vma)                              \
  79         ((transparent_hugepage_flags &                                  \
  80           (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)) ||                     \
  81          (transparent_hugepage_flags &                                  \
  82           (1<<TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG) &&             \
  83           (__vma)->vm_flags & VM_HUGEPAGE))
  84 #define transparent_hugepage_use_zero_page()                            \
  85         (transparent_hugepage_flags &                                   \
  86          (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG))
  87 #ifdef CONFIG_DEBUG_VM
  88 #define transparent_hugepage_debug_cow()                                \
  89         (transparent_hugepage_flags &                                   \
  90          (1<<TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG))
  91 #else /* CONFIG_DEBUG_VM */
  92 #define transparent_hugepage_debug_cow() 0
  93 #endif /* CONFIG_DEBUG_VM */
  94
  95 extern unsigned long transparent_hugepage_flags;
  96 extern int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
  97                           pmd_t *dst_pmd, pmd_t *src_pmd,
  98                           struct vm_area_struct *vma,
  99                           unsigned long addr, unsigned long end);
 100 extern int split_huge_page_to_list(struct page *page, struct list_head *list);
 101 static inline int split_huge_page(struct page *page)
 102 {
 103         return split_huge_page_to_list(page, NULL);
 104 }
 105 extern void __split_huge_page_pmd(struct vm_area_struct *vma,
 106                 unsigned long address, pmd_t *pmd);
 107 #define split_huge_page_pmd(__vma, __address, __pmd)                    \
 108         do {                                                            \
 109                 pmd_t *____pmd = (__pmd);                               \
 110                 if (unlikely(pmd_trans_huge(*____pmd)))                 \
 111                         __split_huge_page_pmd(__vma, __address,         \
 112                                         ____pmd);                       \
 113         }  while (0)
 114 #define wait_split_huge_page(__anon_vma, __pmd)                         \
 115         do {                                                            \
 116                 pmd_t *____pmd = (__pmd);                               \
 117                 anon_vma_lock_write(__anon_vma);                        \
 118                 anon_vma_unlock_write(__anon_vma);                      \
 119                 BUG_ON(pmd_trans_splitting(*____pmd) ||                 \
 120                        pmd_trans_huge(*____pmd));                       \
 121         } while (0)
 122 extern void split_huge_page_pmd_mm(struct mm_struct *mm, unsigned long address,
 123                 pmd_t *pmd);
 124 #if HPAGE_PMD_ORDER >= MAX_ORDER
 125 #error "hugepages can't be allocated by the buddy allocator"
 126 #endif
 127 extern int hugepage_madvise(struct vm_area_struct *vma,
 128                             unsigned long *vm_flags, int advice);
 129 extern void __vma_adjust_trans_huge(struct vm_area_struct *vma,
 130                                     unsigned long start,
 131                                     unsigned long end,
 132                                     long adjust_next);
 133 extern int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
 134                 spinlock_t **ptl);
 135 /* mmap_sem must be held on entry */
 136 static inline int pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
 137                 spinlock_t **ptl)
 138 {
 139         VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem));
 140         if (pmd_trans_huge(*pmd))
 141                 return __pmd_trans_huge_lock(pmd, vma, ptl);
 142         else
 143                 return 0;
 144 }
 145 static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
 146                                          unsigned long start,
 147                                          unsigned long end,
 148                                          long adjust_next)
 149 {
 150         if (!vma->anon_vma || vma->vm_ops)
 151                 return;
 152         __vma_adjust_trans_huge(vma, start, end, adjust_next);
 153 }
 154 static inline int hpage_nr_pages(struct page *page)
 155 {
 156         if (unlikely(PageTransHuge(page)))
 157                 return HPAGE_PMD_NR;
 158         return 1;
 159 }
 160 /*
 161  * compound_trans_head() should be used instead of compound_head(),
 162  * whenever the "page" passed as parameter could be the tail of a
 163  * transparent hugepage that could be undergoing a
 164  * __split_huge_page_refcount(). The page structure layout often
 165  * changes across releases and it makes extensive use of unions. So if
 166  * the page structure layout will change in a way that
 167  * page->first_page gets clobbered by __split_huge_page_refcount, the
 168  * implementation making use of smp_rmb() will be required.
 169  *
 170  * Currently we define compound_trans_head as compound_head, because
 171  * page->private is in the same union with page->first_page, and
 172  * page->private isn't clobbered. However this also means we're
 173  * currently leaving dirt into the page->private field of anonymous
 174  * pages resulting from a THP split, instead of setting page->private
 175  * to zero like for every other page that has PG_private not set. But
 176  * anonymous pages don't use page->private so this is not a problem.
 177  */
 178 #if 0
 179 /* This will be needed if page->private will be clobbered in split_huge_page */
 180 static inline struct page *compound_trans_head(struct page *page)
 181 {
 182         if (PageTail(page)) {
 183                 struct page *head;
 184                 head = page->first_page;
 185                 smp_rmb();
 186                 /*
 187                  * head may be a dangling pointer.
 188                  * __split_huge_page_refcount clears PageTail before
 189                  * overwriting first_page, so if PageTail is still
 190                  * there it means the head pointer isn't dangling.
 191                  */
 192                 if (PageTail(page))
 193                         return head;
 194         }
 195         return page;
 196 }
 197 #else
 198 #define compound_trans_head(page) compound_head(page)
 199 #endif
 200
 201 extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 202                                 unsigned long addr, pmd_t pmd, pmd_t *pmdp);
 203
 204 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 205 #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
 206 #define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
 207 #define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
 208
 209 #define hpage_nr_pages(x) 1
 210
 211 #define transparent_hugepage_enabled(__vma) 0
 212
 213 #define transparent_hugepage_flags 0UL
 214 static inline int
 215 split_huge_page_to_list(struct page *page, struct list_head *list)
 216 {
 217         return 0;
 218 }
 219 static inline int split_huge_page(struct page *page)
 220 {
 221         return 0;
 222 }
 223 #define split_huge_page_pmd(__vma, __address, __pmd)    \
 224         do { } while (0)
 225 #define wait_split_huge_page(__anon_vma, __pmd) \
 226         do { } while (0)
 227 #define split_huge_page_pmd_mm(__mm, __address, __pmd)  \
 228         do { } while (0)
 229 #define compound_trans_head(page) compound_head(page)
 230 static inline int hugepage_madvise(struct vm_area_struct *vma,
 231                                    unsigned long *vm_flags, int advice)
 232 {
 233         BUG();
 234         return 0;
 235 }
 236 static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
 237                                          unsigned long start,
 238                                          unsigned long end,
 239                                          long adjust_next)
 240 {
 241 }
 242 static inline int pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
 243                 spinlock_t **ptl)
 244 {
 245         return 0;
 246 }
 247
 248 static inline int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 249                                         unsigned long addr, pmd_t pmd, pmd_t *pmdp)
 250 {
 251         return 0;
 252 }
 253
 254 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 255
 256 #endif /* _LINUX_HUGE_MM_H */