include/linux/huge_mm.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_HUGE_MM_H
   3 #define _LINUX_HUGE_MM_H
   4
   5 #include <linux/sched/coredump.h>
   6 #include <linux/mm_types.h>
   7
   8 #include <linux/fs.h> /* only for vma_is_dax() */
   9 #include <linux/kobject.h>
  10
  11 vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf);
  12 int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
  13                   pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
  14                   struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma);
  15 void huge_pmd_set_accessed(struct vm_fault *vmf);
  16 int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm,
  17                   pud_t *dst_pud, pud_t *src_pud, unsigned long addr,
  18                   struct vm_area_struct *vma);
  19
  20 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
  21 void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud);
  22 #else
  23 static inline void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
  24 {
  25 }
  26 #endif
  27
  28 vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf);
  29 bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
  30                            pmd_t *pmd, unsigned long addr, unsigned long next);
  31 int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd,
  32                  unsigned long addr);
  33 int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, pud_t *pud,
  34                  unsigned long addr);
  35 bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
  36                    unsigned long new_addr, pmd_t *old_pmd, pmd_t *new_pmd);
  37 int change_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
  38                     pmd_t *pmd, unsigned long addr, pgprot_t newprot,
  39                     unsigned long cp_flags);
  40
  41 vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write);
  42 vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write);
  43
  44 enum transparent_hugepage_flag {
  45         TRANSPARENT_HUGEPAGE_UNSUPPORTED,
  46         TRANSPARENT_HUGEPAGE_FLAG,
  47         TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
  48         TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
  49         TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG,
  50         TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG,
  51         TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
  52         TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG,
  53         TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG,
  54 };
  55
  56 struct kobject;
  57 struct kobj_attribute;
  58
  59 ssize_t single_hugepage_flag_store(struct kobject *kobj,
  60                                    struct kobj_attribute *attr,
  61                                    const char *buf, size_t count,
  62                                    enum transparent_hugepage_flag flag);
  63 ssize_t single_hugepage_flag_show(struct kobject *kobj,
  64                                   struct kobj_attribute *attr, char *buf,
  65                                   enum transparent_hugepage_flag flag);
  66 extern struct kobj_attribute shmem_enabled_attr;
  67 extern struct kobj_attribute thpsize_shmem_enabled_attr;
  68
  69 /*
  70  * Mask of all large folio orders supported for anonymous THP; all orders up to
  71  * and including PMD_ORDER, except order-0 (which is not "huge") and order-1
  72  * (which is a limitation of the THP implementation).
  73  */
  74 #define THP_ORDERS_ALL_ANON     ((BIT(PMD_ORDER + 1) - 1) & ~(BIT(0) | BIT(1)))
  75
  76 /*
  77  * Mask of all large folio orders supported for file THP. Folios in a DAX
  78  * file is never split and the MAX_PAGECACHE_ORDER limit does not apply to
  79  * it.
  80  */
  81 #define THP_ORDERS_ALL_FILE_DAX         \
  82         (BIT(PMD_ORDER) | BIT(PUD_ORDER))
  83 #define THP_ORDERS_ALL_FILE_DEFAULT     \
  84         ((BIT(MAX_PAGECACHE_ORDER + 1) - 1) & ~BIT(0))
  85
  86 /*
  87  * Mask of all large folio orders supported for THP.
  88  */
  89 #define THP_ORDERS_ALL  \
  90         (THP_ORDERS_ALL_ANON | THP_ORDERS_ALL_FILE_DAX | THP_ORDERS_ALL_FILE_DEFAULT)
  91
  92 #define TVA_SMAPS               (1 << 0)        /* Will be used for procfs */
  93 #define TVA_IN_PF               (1 << 1)        /* Page fault handler */
  94 #define TVA_ENFORCE_SYSFS       (1 << 2)        /* Obey sysfs configuration */
  95
  96 #define thp_vma_allowable_order(vma, vm_flags, tva_flags, order) \
  97         (!!thp_vma_allowable_orders(vma, vm_flags, tva_flags, BIT(order)))
  98
  99 #ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
 100 #define HPAGE_PMD_SHIFT PMD_SHIFT
 101 #define HPAGE_PUD_SHIFT PUD_SHIFT
 102 #else
 103 #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
 104 #define HPAGE_PUD_SHIFT ({ BUILD_BUG(); 0; })
 105 #endif
 106
 107 #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
 108 #define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
 109 #define HPAGE_PMD_MASK  (~(HPAGE_PMD_SIZE - 1))
 110 #define HPAGE_PMD_SIZE  ((1UL) << HPAGE_PMD_SHIFT)
 111
 112 #define HPAGE_PUD_ORDER (HPAGE_PUD_SHIFT-PAGE_SHIFT)
 113 #define HPAGE_PUD_NR (1<<HPAGE_PUD_ORDER)
 114 #define HPAGE_PUD_MASK  (~(HPAGE_PUD_SIZE - 1))
 115 #define HPAGE_PUD_SIZE  ((1UL) << HPAGE_PUD_SHIFT)
 116
 117 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 118
 119 extern unsigned long transparent_hugepage_flags;
 120 extern unsigned long huge_anon_orders_always;
 121 extern unsigned long huge_anon_orders_madvise;
 122 extern unsigned long huge_anon_orders_inherit;
 123
 124 static inline bool hugepage_global_enabled(void)
 125 {
 126         return transparent_hugepage_flags &
 127                         ((1<<TRANSPARENT_HUGEPAGE_FLAG) |
 128                         (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG));
 129 }
 130
 131 static inline bool hugepage_global_always(void)
 132 {
 133         return transparent_hugepage_flags &
 134                         (1<<TRANSPARENT_HUGEPAGE_FLAG);
 135 }
 136
 137 static inline int highest_order(unsigned long orders)
 138 {
 139         return fls_long(orders) - 1;
 140 }
 141
 142 static inline int next_order(unsigned long *orders, int prev)
 143 {
 144         *orders &= ~BIT(prev);
 145         return highest_order(*orders);
 146 }
 147
 148 /*
 149  * Do the below checks:
 150  *   - For file vma, check if the linear page offset of vma is
 151  *     order-aligned within the file.  The hugepage is
 152  *     guaranteed to be order-aligned within the file, but we must
 153  *     check that the order-aligned addresses in the VMA map to
 154  *     order-aligned offsets within the file, else the hugepage will
 155  *     not be mappable.
 156  *   - For all vmas, check if the haddr is in an aligned hugepage
 157  *     area.
 158  */
 159 static inline bool thp_vma_suitable_order(struct vm_area_struct *vma,
 160                 unsigned long addr, int order)
 161 {
 162         unsigned long hpage_size = PAGE_SIZE << order;
 163         unsigned long haddr;
 164
 165         /* Don't have to check pgoff for anonymous vma */
 166         if (!vma_is_anonymous(vma)) {
 167                 if (!IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
 168                                 hpage_size >> PAGE_SHIFT))
 169                         return false;
 170         }
 171
 172         haddr = ALIGN_DOWN(addr, hpage_size);
 173
 174         if (haddr < vma->vm_start || haddr + hpage_size > vma->vm_end)
 175                 return false;
 176         return true;
 177 }
 178
 179 /*
 180  * Filter the bitfield of input orders to the ones suitable for use in the vma.
 181  * See thp_vma_suitable_order().
 182  * All orders that pass the checks are returned as a bitfield.
 183  */
 184 static inline unsigned long thp_vma_suitable_orders(struct vm_area_struct *vma,
 185                 unsigned long addr, unsigned long orders)
 186 {
 187         int order;
 188
 189         /*
 190          * Iterate over orders, highest to lowest, removing orders that don't
 191          * meet alignment requirements from the set. Exit loop at first order
 192          * that meets requirements, since all lower orders must also meet
 193          * requirements.
 194          */
 195
 196         order = highest_order(orders);
 197
 198         while (orders) {
 199                 if (thp_vma_suitable_order(vma, addr, order))
 200                         break;
 201                 order = next_order(&orders, order);
 202         }
 203
 204         return orders;
 205 }
 206
 207 static inline bool file_thp_enabled(struct vm_area_struct *vma)
 208 {
 209         struct inode *inode;
 210
 211         if (!vma->vm_file)
 212                 return false;
 213
 214         inode = vma->vm_file->f_inode;
 215
 216         return (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS)) &&
 217                !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
 218 }
 219
 220 unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma,
 221                                          unsigned long vm_flags,
 222                                          unsigned long tva_flags,
 223                                          unsigned long orders);
 224
 225 /**
 226  * thp_vma_allowable_orders - determine hugepage orders that are allowed for vma
 227  * @vma:  the vm area to check
 228  * @vm_flags: use these vm_flags instead of vma->vm_flags
 229  * @tva_flags: Which TVA flags to honour
 230  * @orders: bitfield of all orders to consider
 231  *
 232  * Calculates the intersection of the requested hugepage orders and the allowed
 233  * hugepage orders for the provided vma. Permitted orders are encoded as a set
 234  * bit at the corresponding bit position (bit-2 corresponds to order-2, bit-3
 235  * corresponds to order-3, etc). Order-0 is never considered a hugepage order.
 236  *
 237  * Return: bitfield of orders allowed for hugepage in the vma. 0 if no hugepage
 238  * orders are allowed.
 239  */
 240 static inline
 241 unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma,
 242                                        unsigned long vm_flags,
 243                                        unsigned long tva_flags,
 244                                        unsigned long orders)
 245 {
 246         /* Optimization to check if required orders are enabled early. */
 247         if ((tva_flags & TVA_ENFORCE_SYSFS) && vma_is_anonymous(vma)) {
 248                 unsigned long mask = READ_ONCE(huge_anon_orders_always);
 249
 250                 if (vm_flags & VM_HUGEPAGE)
 251                         mask |= READ_ONCE(huge_anon_orders_madvise);
 252                 if (hugepage_global_always() ||
 253                     ((vm_flags & VM_HUGEPAGE) && hugepage_global_enabled()))
 254                         mask |= READ_ONCE(huge_anon_orders_inherit);
 255
 256                 orders &= mask;
 257                 if (!orders)
 258                         return 0;
 259         }
 260
 261         return __thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders);
 262 }
 263
 264 struct thpsize {
 265         struct kobject kobj;
 266         struct list_head node;
 267         int order;
 268 };
 269
 270 #define to_thpsize(kobj) container_of(kobj, struct thpsize, kobj)
 271
 272 enum mthp_stat_item {
 273         MTHP_STAT_ANON_FAULT_ALLOC,
 274         MTHP_STAT_ANON_FAULT_FALLBACK,
 275         MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE,
 276         MTHP_STAT_SWPOUT,
 277         MTHP_STAT_SWPOUT_FALLBACK,
 278         MTHP_STAT_SHMEM_ALLOC,
 279         MTHP_STAT_SHMEM_FALLBACK,
 280         MTHP_STAT_SHMEM_FALLBACK_CHARGE,
 281         MTHP_STAT_SPLIT,
 282         MTHP_STAT_SPLIT_FAILED,
 283         MTHP_STAT_SPLIT_DEFERRED,
 284         __MTHP_STAT_COUNT
 285 };
 286
 287 struct mthp_stat {
 288         unsigned long stats[ilog2(MAX_PTRS_PER_PTE) + 1][__MTHP_STAT_COUNT];
 289 };
 290
 291 #ifdef CONFIG_SYSFS
 292 DECLARE_PER_CPU(struct mthp_stat, mthp_stats);
 293
 294 static inline void count_mthp_stat(int order, enum mthp_stat_item item)
 295 {
 296         if (order <= 0 || order > PMD_ORDER)
 297                 return;
 298
 299         this_cpu_inc(mthp_stats.stats[order][item]);
 300 }
 301 #else
 302 static inline void count_mthp_stat(int order, enum mthp_stat_item item)
 303 {
 304 }
 305 #endif
 306
 307 #define transparent_hugepage_use_zero_page()                            \
 308         (transparent_hugepage_flags &                                   \
 309          (1<<TRANSPARENT_HUGEPAGE_USE_ZERO_PAGE_FLAG))
 310
 311 unsigned long thp_get_unmapped_area(struct file *filp, unsigned long addr,
 312                 unsigned long len, unsigned long pgoff, unsigned long flags);
 313 unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long addr,
 314                 unsigned long len, unsigned long pgoff, unsigned long flags,
 315                 vm_flags_t vm_flags);
 316
 317 bool can_split_folio(struct folio *folio, int *pextra_pins);
 318 int split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
 319                 unsigned int new_order);
 320 static inline int split_huge_page(struct page *page)
 321 {
 322         return split_huge_page_to_list_to_order(page, NULL, 0);
 323 }
 324 void deferred_split_folio(struct folio *folio);
 325
 326 void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 327                 unsigned long address, bool freeze, struct folio *folio);
 328
 329 #define split_huge_pmd(__vma, __pmd, __address)                         \
 330         do {                                                            \
 331                 pmd_t *____pmd = (__pmd);                               \
 332                 if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd)   \
 333                                         || pmd_devmap(*____pmd))        \
 334                         __split_huge_pmd(__vma, __pmd, __address,       \
 335                                                 false, NULL);           \
 336         }  while (0)
 337
 338
 339 void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
 340                 bool freeze, struct folio *folio);
 341
 342 void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
 343                 unsigned long address);
 344
 345 #define split_huge_pud(__vma, __pud, __address)                         \
 346         do {                                                            \
 347                 pud_t *____pud = (__pud);                               \
 348                 if (pud_trans_huge(*____pud)                            \
 349                                         || pud_devmap(*____pud))        \
 350                         __split_huge_pud(__vma, __pud, __address);      \
 351         }  while (0)
 352
 353 int hugepage_madvise(struct vm_area_struct *vma, unsigned long *vm_flags,
 354                      int advice);
 355 int madvise_collapse(struct vm_area_struct *vma,
 356                      struct vm_area_struct **prev,
 357                      unsigned long start, unsigned long end);
 358 void vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start,
 359                            unsigned long end, long adjust_next);
 360 spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma);
 361 spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma);
 362
 363 static inline int is_swap_pmd(pmd_t pmd)
 364 {
 365         return !pmd_none(pmd) && !pmd_present(pmd);
 366 }
 367
 368 /* mmap_lock must be held on entry */
 369 static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
 370                 struct vm_area_struct *vma)
 371 {
 372         if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
 373                 return __pmd_trans_huge_lock(pmd, vma);
 374         else
 375                 return NULL;
 376 }
 377 static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
 378                 struct vm_area_struct *vma)
 379 {
 380         if (pud_trans_huge(*pud) || pud_devmap(*pud))
 381                 return __pud_trans_huge_lock(pud, vma);
 382         else
 383                 return NULL;
 384 }
 385
 386 /**
 387  * folio_test_pmd_mappable - Can we map this folio with a PMD?
 388  * @folio: The folio to test
 389  */
 390 static inline bool folio_test_pmd_mappable(struct folio *folio)
 391 {
 392         return folio_order(folio) >= HPAGE_PMD_ORDER;
 393 }
 394
 395 struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
 396                 pmd_t *pmd, int flags, struct dev_pagemap **pgmap);
 397
 398 vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf);
 399
 400 extern struct folio *huge_zero_folio;
 401 extern unsigned long huge_zero_pfn;
 402
 403 static inline bool is_huge_zero_folio(const struct folio *folio)
 404 {
 405         return READ_ONCE(huge_zero_folio) == folio;
 406 }
 407
 408 static inline bool is_huge_zero_pmd(pmd_t pmd)
 409 {
 410         return pmd_present(pmd) && READ_ONCE(huge_zero_pfn) == pmd_pfn(pmd);
 411 }
 412
 413 static inline bool is_huge_zero_pud(pud_t pud)
 414 {
 415         return false;
 416 }
 417
 418 struct folio *mm_get_huge_zero_folio(struct mm_struct *mm);
 419 void mm_put_huge_zero_folio(struct mm_struct *mm);
 420
 421 #define mk_huge_pmd(page, prot) pmd_mkhuge(mk_pmd(page, prot))
 422
 423 static inline bool thp_migration_supported(void)
 424 {
 425         return IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION);
 426 }
 427
 428 void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address,
 429                            pmd_t *pmd, bool freeze, struct folio *folio);
 430 bool unmap_huge_pmd_locked(struct vm_area_struct *vma, unsigned long addr,
 431                            pmd_t *pmdp, struct folio *folio);
 432
 433 #else /* CONFIG_TRANSPARENT_HUGEPAGE */
 434
 435 static inline bool folio_test_pmd_mappable(struct folio *folio)
 436 {
 437         return false;
 438 }
 439
 440 static inline bool thp_vma_suitable_order(struct vm_area_struct *vma,
 441                 unsigned long addr, int order)
 442 {
 443         return false;
 444 }
 445
 446 static inline unsigned long thp_vma_suitable_orders(struct vm_area_struct *vma,
 447                 unsigned long addr, unsigned long orders)
 448 {
 449         return 0;
 450 }
 451
 452 static inline unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma,
 453                                         unsigned long vm_flags,
 454                                         unsigned long tva_flags,
 455                                         unsigned long orders)
 456 {
 457         return 0;
 458 }
 459
 460 #define transparent_hugepage_flags 0UL
 461
 462 #define thp_get_unmapped_area   NULL
 463
 464 static inline unsigned long
 465 thp_get_unmapped_area_vmflags(struct file *filp, unsigned long addr,
 466                               unsigned long len, unsigned long pgoff,
 467                               unsigned long flags, vm_flags_t vm_flags)
 468 {
 469         return 0;
 470 }
 471
 472 static inline bool
 473 can_split_folio(struct folio *folio, int *pextra_pins)
 474 {
 475         return false;
 476 }
 477 static inline int
 478 split_huge_page_to_list_to_order(struct page *page, struct list_head *list,
 479                 unsigned int new_order)
 480 {
 481         return 0;
 482 }
 483 static inline int split_huge_page(struct page *page)
 484 {
 485         return 0;
 486 }
 487 static inline void deferred_split_folio(struct folio *folio) {}
 488 #define split_huge_pmd(__vma, __pmd, __address) \
 489         do { } while (0)
 490
 491 static inline void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 492                 unsigned long address, bool freeze, struct folio *folio) {}
 493 static inline void split_huge_pmd_address(struct vm_area_struct *vma,
 494                 unsigned long address, bool freeze, struct folio *folio) {}
 495 static inline void split_huge_pmd_locked(struct vm_area_struct *vma,
 496                                          unsigned long address, pmd_t *pmd,
 497                                          bool freeze, struct folio *folio) {}
 498
 499 static inline bool unmap_huge_pmd_locked(struct vm_area_struct *vma,
 500                                          unsigned long addr, pmd_t *pmdp,
 501                                          struct folio *folio)
 502 {
 503         return false;
 504 }
 505
 506 #define split_huge_pud(__vma, __pmd, __address) \
 507         do { } while (0)
 508
 509 static inline int hugepage_madvise(struct vm_area_struct *vma,
 510                                    unsigned long *vm_flags, int advice)
 511 {
 512         return -EINVAL;
 513 }
 514
 515 static inline int madvise_collapse(struct vm_area_struct *vma,
 516                                    struct vm_area_struct **prev,
 517                                    unsigned long start, unsigned long end)
 518 {
 519         return -EINVAL;
 520 }
 521
 522 static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
 523                                          unsigned long start,
 524                                          unsigned long end,
 525                                          long adjust_next)
 526 {
 527 }
 528 static inline int is_swap_pmd(pmd_t pmd)
 529 {
 530         return 0;
 531 }
 532 static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
 533                 struct vm_area_struct *vma)
 534 {
 535         return NULL;
 536 }
 537 static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
 538                 struct vm_area_struct *vma)
 539 {
 540         return NULL;
 541 }
 542
 543 static inline vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
 544 {
 545         return 0;
 546 }
 547
 548 static inline bool is_huge_zero_folio(const struct folio *folio)
 549 {
 550         return false;
 551 }
 552
 553 static inline bool is_huge_zero_pmd(pmd_t pmd)
 554 {
 555         return false;
 556 }
 557
 558 static inline bool is_huge_zero_pud(pud_t pud)
 559 {
 560         return false;
 561 }
 562
 563 static inline void mm_put_huge_zero_folio(struct mm_struct *mm)
 564 {
 565         return;
 566 }
 567
 568 static inline struct page *follow_devmap_pmd(struct vm_area_struct *vma,
 569         unsigned long addr, pmd_t *pmd, int flags, struct dev_pagemap **pgmap)
 570 {
 571         return NULL;
 572 }
 573
 574 static inline bool thp_migration_supported(void)
 575 {
 576         return false;
 577 }
 578
 579 static inline int highest_order(unsigned long orders)
 580 {
 581         return 0;
 582 }
 583
 584 static inline int next_order(unsigned long *orders, int prev)
 585 {
 586         return 0;
 587 }
 588 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 589
 590 static inline int split_folio_to_list_to_order(struct folio *folio,
 591                 struct list_head *list, int new_order)
 592 {
 593         return split_huge_page_to_list_to_order(&folio->page, list, new_order);
 594 }
 595
 596 static inline int split_folio_to_order(struct folio *folio, int new_order)
 597 {
 598         return split_folio_to_list_to_order(folio, NULL, new_order);
 599 }
 600
 601 #define split_folio_to_list(f, l) split_folio_to_list_to_order(f, l, 0)
 602 #define split_folio(f) split_folio_to_order(f, 0)
 603
 604 #endif /* _LINUX_HUGE_MM_H */