1 /* 2 * Generic hugetlb support. 3 * (C) Nadia Yvette Chambers, April 2004 4 */ 5 #include <linux/list.h> 6 #include <linux/init.h> 7 #include <linux/module.h> 8 #include <linux/mm.h> 9 #include <linux/seq_file.h> 10 #include <linux/sysctl.h> 11 #include <linux/highmem.h> 12 #include <linux/mmu_notifier.h> 13 #include <linux/nodemask.h> 14 #include <linux/pagemap.h> 15 #include <linux/mempolicy.h> 16 #include <linux/cpuset.h> 17 #include <linux/mutex.h> 18 #include <linux/bootmem.h> 19 #include <linux/sysfs.h> 20 #include <linux/slab.h> 21 #include <linux/rmap.h> 22 #include <linux/swap.h> 23 #include <linux/swapops.h> 24 25 #include <asm/page.h> 26 #include <asm/pgtable.h> 27 #include <asm/tlb.h> 28 29 #include <linux/io.h> 30 #include <linux/hugetlb.h> 31 #include <linux/hugetlb_cgroup.h> 32 #include <linux/node.h> 33 #include "internal.h" 34 35 const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 36 static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 37 unsigned long hugepages_treat_as_movable; 38 39 int hugetlb_max_hstate __read_mostly; 40 unsigned int default_hstate_idx; 41 struct hstate hstates[HUGE_MAX_HSTATE]; 42 43 __initdata LIST_HEAD(huge_boot_pages); 44 45 /* for command line parsing */ 46 static struct hstate * __initdata parsed_hstate; 47 static unsigned long __initdata default_hstate_max_huge_pages; 48 static unsigned long __initdata default_hstate_size; 49 50 /* 51 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages 52 */ 53 DEFINE_SPINLOCK(hugetlb_lock); 54 55 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) 56 { 57 bool free = (spool->count == 0) && (spool->used_hpages == 0); 58 59 spin_unlock(&spool->lock); 60 61 /* If no pages are used, and no other handles to the subpool 62 * remain, free the subpool the subpool remain */ 63 if (free) 64 kfree(spool); 65 } 66 67 struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) 68 { 69 struct hugepage_subpool *spool; 70 71 spool = kmalloc(sizeof(*spool), GFP_KERNEL); 72 if (!spool) 73 return NULL; 74 75 spin_lock_init(&spool->lock); 76 spool->count = 1; 77 spool->max_hpages = nr_blocks; 78 spool->used_hpages = 0; 79 80 return spool; 81 } 82 83 void hugepage_put_subpool(struct hugepage_subpool *spool) 84 { 85 spin_lock(&spool->lock); 86 BUG_ON(!spool->count); 87 spool->count--; 88 unlock_or_release_subpool(spool); 89 } 90 91 static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, 92 long delta) 93 { 94 int ret = 0; 95 96 if (!spool) 97 return 0; 98 99 spin_lock(&spool->lock); 100 if ((spool->used_hpages + delta) <= spool->max_hpages) { 101 spool->used_hpages += delta; 102 } else { 103 ret = -ENOMEM; 104 } 105 spin_unlock(&spool->lock); 106 107 return ret; 108 } 109 110 static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, 111 long delta) 112 { 113 if (!spool) 114 return; 115 116 spin_lock(&spool->lock); 117 spool->used_hpages -= delta; 118 /* If hugetlbfs_put_super couldn't free spool due to 119 * an outstanding quota reference, free it now. */ 120 unlock_or_release_subpool(spool); 121 } 122 123 static inline struct hugepage_subpool *subpool_inode(struct inode *inode) 124 { 125 return HUGETLBFS_SB(inode->i_sb)->spool; 126 } 127 128 static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) 129 { 130 return subpool_inode(file_inode(vma->vm_file)); 131 } 132 133 /* 134 * Region tracking -- allows tracking of reservations and instantiated pages 135 * across the pages in a mapping. 136 * 137 * The region data structures are protected by a combination of the mmap_sem 138 * and the hugetlb_instantion_mutex. To access or modify a region the caller 139 * must either hold the mmap_sem for write, or the mmap_sem for read and 140 * the hugetlb_instantiation mutex: 141 * 142 * down_write(&mm->mmap_sem); 143 * or 144 * down_read(&mm->mmap_sem); 145 * mutex_lock(&hugetlb_instantiation_mutex); 146 */ 147 struct file_region { 148 struct list_head link; 149 long from; 150 long to; 151 }; 152 153 static long region_add(struct list_head *head, long f, long t) 154 { 155 struct file_region *rg, *nrg, *trg; 156 157 /* Locate the region we are either in or before. */ 158 list_for_each_entry(rg, head, link) 159 if (f <= rg->to) 160 break; 161 162 /* Round our left edge to the current segment if it encloses us. */ 163 if (f > rg->from) 164 f = rg->from; 165 166 /* Check for and consume any regions we now overlap with. */ 167 nrg = rg; 168 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 169 if (&rg->link == head) 170 break; 171 if (rg->from > t) 172 break; 173 174 /* If this area reaches higher then extend our area to 175 * include it completely. If this is not the first area 176 * which we intend to reuse, free it. */ 177 if (rg->to > t) 178 t = rg->to; 179 if (rg != nrg) { 180 list_del(&rg->link); 181 kfree(rg); 182 } 183 } 184 nrg->from = f; 185 nrg->to = t; 186 return 0; 187 } 188 189 static long region_chg(struct list_head *head, long f, long t) 190 { 191 struct file_region *rg, *nrg; 192 long chg = 0; 193 194 /* Locate the region we are before or in. */ 195 list_for_each_entry(rg, head, link) 196 if (f <= rg->to) 197 break; 198 199 /* If we are below the current region then a new region is required. 200 * Subtle, allocate a new region at the position but make it zero 201 * size such that we can guarantee to record the reservation. */ 202 if (&rg->link == head || t < rg->from) { 203 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 204 if (!nrg) 205 return -ENOMEM; 206 nrg->from = f; 207 nrg->to = f; 208 INIT_LIST_HEAD(&nrg->link); 209 list_add(&nrg->link, rg->link.prev); 210 211 return t - f; 212 } 213 214 /* Round our left edge to the current segment if it encloses us. */ 215 if (f > rg->from) 216 f = rg->from; 217 chg = t - f; 218 219 /* Check for and consume any regions we now overlap with. */ 220 list_for_each_entry(rg, rg->link.prev, link) { 221 if (&rg->link == head) 222 break; 223 if (rg->from > t) 224 return chg; 225 226 /* We overlap with this area, if it extends further than 227 * us then we must extend ourselves. Account for its 228 * existing reservation. */ 229 if (rg->to > t) { 230 chg += rg->to - t; 231 t = rg->to; 232 } 233 chg -= rg->to - rg->from; 234 } 235 return chg; 236 } 237 238 static long region_truncate(struct list_head *head, long end) 239 { 240 struct file_region *rg, *trg; 241 long chg = 0; 242 243 /* Locate the region we are either in or before. */ 244 list_for_each_entry(rg, head, link) 245 if (end <= rg->to) 246 break; 247 if (&rg->link == head) 248 return 0; 249 250 /* If we are in the middle of a region then adjust it. */ 251 if (end > rg->from) { 252 chg = rg->to - end; 253 rg->to = end; 254 rg = list_entry(rg->link.next, typeof(*rg), link); 255 } 256 257 /* Drop any remaining regions. */ 258 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 259 if (&rg->link == head) 260 break; 261 chg += rg->to - rg->from; 262 list_del(&rg->link); 263 kfree(rg); 264 } 265 return chg; 266 } 267 268 static long region_count(struct list_head *head, long f, long t) 269 { 270 struct file_region *rg; 271 long chg = 0; 272 273 /* Locate each segment we overlap with, and count that overlap. */ 274 list_for_each_entry(rg, head, link) { 275 long seg_from; 276 long seg_to; 277 278 if (rg->to <= f) 279 continue; 280 if (rg->from >= t) 281 break; 282 283 seg_from = max(rg->from, f); 284 seg_to = min(rg->to, t); 285 286 chg += seg_to - seg_from; 287 } 288 289 return chg; 290 } 291 292 /* 293 * Convert the address within this vma to the page offset within 294 * the mapping, in pagecache page units; huge pages here. 295 */ 296 static pgoff_t vma_hugecache_offset(struct hstate *h, 297 struct vm_area_struct *vma, unsigned long address) 298 { 299 return ((address - vma->vm_start) >> huge_page_shift(h)) + 300 (vma->vm_pgoff >> huge_page_order(h)); 301 } 302 303 pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 304 unsigned long address) 305 { 306 return vma_hugecache_offset(hstate_vma(vma), vma, address); 307 } 308 309 /* 310 * Return the size of the pages allocated when backing a VMA. In the majority 311 * cases this will be same size as used by the page table entries. 312 */ 313 unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) 314 { 315 struct hstate *hstate; 316 317 if (!is_vm_hugetlb_page(vma)) 318 return PAGE_SIZE; 319 320 hstate = hstate_vma(vma); 321 322 return 1UL << (hstate->order + PAGE_SHIFT); 323 } 324 EXPORT_SYMBOL_GPL(vma_kernel_pagesize); 325 326 /* 327 * Return the page size being used by the MMU to back a VMA. In the majority 328 * of cases, the page size used by the kernel matches the MMU size. On 329 * architectures where it differs, an architecture-specific version of this 330 * function is required. 331 */ 332 #ifndef vma_mmu_pagesize 333 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 334 { 335 return vma_kernel_pagesize(vma); 336 } 337 #endif 338 339 /* 340 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 341 * bits of the reservation map pointer, which are always clear due to 342 * alignment. 343 */ 344 #define HPAGE_RESV_OWNER (1UL << 0) 345 #define HPAGE_RESV_UNMAPPED (1UL << 1) 346 #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 347 348 /* 349 * These helpers are used to track how many pages are reserved for 350 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 351 * is guaranteed to have their future faults succeed. 352 * 353 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 354 * the reserve counters are updated with the hugetlb_lock held. It is safe 355 * to reset the VMA at fork() time as it is not in use yet and there is no 356 * chance of the global counters getting corrupted as a result of the values. 357 * 358 * The private mapping reservation is represented in a subtly different 359 * manner to a shared mapping. A shared mapping has a region map associated 360 * with the underlying file, this region map represents the backing file 361 * pages which have ever had a reservation assigned which this persists even 362 * after the page is instantiated. A private mapping has a region map 363 * associated with the original mmap which is attached to all VMAs which 364 * reference it, this region map represents those offsets which have consumed 365 * reservation ie. where pages have been instantiated. 366 */ 367 static unsigned long get_vma_private_data(struct vm_area_struct *vma) 368 { 369 return (unsigned long)vma->vm_private_data; 370 } 371 372 static void set_vma_private_data(struct vm_area_struct *vma, 373 unsigned long value) 374 { 375 vma->vm_private_data = (void *)value; 376 } 377 378 struct resv_map { 379 struct kref refs; 380 struct list_head regions; 381 }; 382 383 static struct resv_map *resv_map_alloc(void) 384 { 385 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 386 if (!resv_map) 387 return NULL; 388 389 kref_init(&resv_map->refs); 390 INIT_LIST_HEAD(&resv_map->regions); 391 392 return resv_map; 393 } 394 395 static void resv_map_release(struct kref *ref) 396 { 397 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 398 399 /* Clear out any active regions before we release the map. */ 400 region_truncate(&resv_map->regions, 0); 401 kfree(resv_map); 402 } 403 404 static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 405 { 406 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 407 if (!(vma->vm_flags & VM_MAYSHARE)) 408 return (struct resv_map *)(get_vma_private_data(vma) & 409 ~HPAGE_RESV_MASK); 410 return NULL; 411 } 412 413 static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 414 { 415 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 416 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 417 418 set_vma_private_data(vma, (get_vma_private_data(vma) & 419 HPAGE_RESV_MASK) | (unsigned long)map); 420 } 421 422 static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 423 { 424 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 425 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 426 427 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 428 } 429 430 static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 431 { 432 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 433 434 return (get_vma_private_data(vma) & flag) != 0; 435 } 436 437 /* Decrement the reserved pages in the hugepage pool by one */ 438 static void decrement_hugepage_resv_vma(struct hstate *h, 439 struct vm_area_struct *vma) 440 { 441 if (vma->vm_flags & VM_NORESERVE) 442 return; 443 444 if (vma->vm_flags & VM_MAYSHARE) { 445 /* Shared mappings always use reserves */ 446 h->resv_huge_pages--; 447 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 448 /* 449 * Only the process that called mmap() has reserves for 450 * private mappings. 451 */ 452 h->resv_huge_pages--; 453 } 454 } 455 456 /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 457 void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 458 { 459 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 460 if (!(vma->vm_flags & VM_MAYSHARE)) 461 vma->vm_private_data = (void *)0; 462 } 463 464 /* Returns true if the VMA has associated reserve pages */ 465 static int vma_has_reserves(struct vm_area_struct *vma) 466 { 467 if (vma->vm_flags & VM_MAYSHARE) 468 return 1; 469 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 470 return 1; 471 return 0; 472 } 473 474 static void copy_gigantic_page(struct page *dst, struct page *src) 475 { 476 int i; 477 struct hstate *h = page_hstate(src); 478 struct page *dst_base = dst; 479 struct page *src_base = src; 480 481 for (i = 0; i < pages_per_huge_page(h); ) { 482 cond_resched(); 483 copy_highpage(dst, src); 484 485 i++; 486 dst = mem_map_next(dst, dst_base, i); 487 src = mem_map_next(src, src_base, i); 488 } 489 } 490 491 void copy_huge_page(struct page *dst, struct page *src) 492 { 493 int i; 494 struct hstate *h = page_hstate(src); 495 496 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 497 copy_gigantic_page(dst, src); 498 return; 499 } 500 501 might_sleep(); 502 for (i = 0; i < pages_per_huge_page(h); i++) { 503 cond_resched(); 504 copy_highpage(dst + i, src + i); 505 } 506 } 507 508 static void enqueue_huge_page(struct hstate *h, struct page *page) 509 { 510 int nid = page_to_nid(page); 511 list_move(&page->lru, &h->hugepage_freelists[nid]); 512 h->free_huge_pages++; 513 h->free_huge_pages_node[nid]++; 514 } 515 516 static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 517 { 518 struct page *page; 519 520 if (list_empty(&h->hugepage_freelists[nid])) 521 return NULL; 522 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); 523 list_move(&page->lru, &h->hugepage_activelist); 524 set_page_refcounted(page); 525 h->free_huge_pages--; 526 h->free_huge_pages_node[nid]--; 527 return page; 528 } 529 530 static struct page *dequeue_huge_page_vma(struct hstate *h, 531 struct vm_area_struct *vma, 532 unsigned long address, int avoid_reserve) 533 { 534 struct page *page = NULL; 535 struct mempolicy *mpol; 536 nodemask_t *nodemask; 537 struct zonelist *zonelist; 538 struct zone *zone; 539 struct zoneref *z; 540 unsigned int cpuset_mems_cookie; 541 542 retry_cpuset: 543 cpuset_mems_cookie = get_mems_allowed(); 544 zonelist = huge_zonelist(vma, address, 545 htlb_alloc_mask, &mpol, &nodemask); 546 /* 547 * A child process with MAP_PRIVATE mappings created by their parent 548 * have no page reserves. This check ensures that reservations are 549 * not "stolen". The child may still get SIGKILLed 550 */ 551 if (!vma_has_reserves(vma) && 552 h->free_huge_pages - h->resv_huge_pages == 0) 553 goto err; 554 555 /* If reserves cannot be used, ensure enough pages are in the pool */ 556 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 557 goto err; 558 559 for_each_zone_zonelist_nodemask(zone, z, zonelist, 560 MAX_NR_ZONES - 1, nodemask) { 561 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { 562 page = dequeue_huge_page_node(h, zone_to_nid(zone)); 563 if (page) { 564 if (!avoid_reserve) 565 decrement_hugepage_resv_vma(h, vma); 566 break; 567 } 568 } 569 } 570 571 mpol_cond_put(mpol); 572 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page)) 573 goto retry_cpuset; 574 return page; 575 576 err: 577 mpol_cond_put(mpol); 578 return NULL; 579 } 580 581 static void update_and_free_page(struct hstate *h, struct page *page) 582 { 583 int i; 584 585 VM_BUG_ON(h->order >= MAX_ORDER); 586 587 h->nr_huge_pages--; 588 h->nr_huge_pages_node[page_to_nid(page)]--; 589 for (i = 0; i < pages_per_huge_page(h); i++) { 590 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 591 1 << PG_referenced | 1 << PG_dirty | 592 1 << PG_active | 1 << PG_reserved | 593 1 << PG_private | 1 << PG_writeback); 594 } 595 VM_BUG_ON(hugetlb_cgroup_from_page(page)); 596 set_compound_page_dtor(page, NULL); 597 set_page_refcounted(page); 598 arch_release_hugepage(page); 599 __free_pages(page, huge_page_order(h)); 600 } 601 602 struct hstate *size_to_hstate(unsigned long size) 603 { 604 struct hstate *h; 605 606 for_each_hstate(h) { 607 if (huge_page_size(h) == size) 608 return h; 609 } 610 return NULL; 611 } 612 613 static void free_huge_page(struct page *page) 614 { 615 /* 616 * Can't pass hstate in here because it is called from the 617 * compound page destructor. 618 */ 619 struct hstate *h = page_hstate(page); 620 int nid = page_to_nid(page); 621 struct hugepage_subpool *spool = 622 (struct hugepage_subpool *)page_private(page); 623 624 set_page_private(page, 0); 625 page->mapping = NULL; 626 BUG_ON(page_count(page)); 627 BUG_ON(page_mapcount(page)); 628 629 spin_lock(&hugetlb_lock); 630 hugetlb_cgroup_uncharge_page(hstate_index(h), 631 pages_per_huge_page(h), page); 632 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 633 /* remove the page from active list */ 634 list_del(&page->lru); 635 update_and_free_page(h, page); 636 h->surplus_huge_pages--; 637 h->surplus_huge_pages_node[nid]--; 638 } else { 639 arch_clear_hugepage_flags(page); 640 enqueue_huge_page(h, page); 641 } 642 spin_unlock(&hugetlb_lock); 643 hugepage_subpool_put_pages(spool, 1); 644 } 645 646 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 647 { 648 INIT_LIST_HEAD(&page->lru); 649 set_compound_page_dtor(page, free_huge_page); 650 spin_lock(&hugetlb_lock); 651 set_hugetlb_cgroup(page, NULL); 652 h->nr_huge_pages++; 653 h->nr_huge_pages_node[nid]++; 654 spin_unlock(&hugetlb_lock); 655 put_page(page); /* free it into the hugepage allocator */ 656 } 657 658 static void prep_compound_gigantic_page(struct page *page, unsigned long order) 659 { 660 int i; 661 int nr_pages = 1 << order; 662 struct page *p = page + 1; 663 664 /* we rely on prep_new_huge_page to set the destructor */ 665 set_compound_order(page, order); 666 __SetPageHead(page); 667 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 668 __SetPageTail(p); 669 set_page_count(p, 0); 670 p->first_page = page; 671 } 672 } 673 674 /* 675 * PageHuge() only returns true for hugetlbfs pages, but not for normal or 676 * transparent huge pages. See the PageTransHuge() documentation for more 677 * details. 678 */ 679 int PageHuge(struct page *page) 680 { 681 compound_page_dtor *dtor; 682 683 if (!PageCompound(page)) 684 return 0; 685 686 page = compound_head(page); 687 dtor = get_compound_page_dtor(page); 688 689 return dtor == free_huge_page; 690 } 691 EXPORT_SYMBOL_GPL(PageHuge); 692 693 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 694 { 695 struct page *page; 696 697 if (h->order >= MAX_ORDER) 698 return NULL; 699 700 page = alloc_pages_exact_node(nid, 701 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 702 __GFP_REPEAT|__GFP_NOWARN, 703 huge_page_order(h)); 704 if (page) { 705 if (arch_prepare_hugepage(page)) { 706 __free_pages(page, huge_page_order(h)); 707 return NULL; 708 } 709 prep_new_huge_page(h, page, nid); 710 } 711 712 return page; 713 } 714 715 /* 716 * common helper functions for hstate_next_node_to_{alloc|free}. 717 * We may have allocated or freed a huge page based on a different 718 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 719 * be outside of *nodes_allowed. Ensure that we use an allowed 720 * node for alloc or free. 721 */ 722 static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 723 { 724 nid = next_node(nid, *nodes_allowed); 725 if (nid == MAX_NUMNODES) 726 nid = first_node(*nodes_allowed); 727 VM_BUG_ON(nid >= MAX_NUMNODES); 728 729 return nid; 730 } 731 732 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 733 { 734 if (!node_isset(nid, *nodes_allowed)) 735 nid = next_node_allowed(nid, nodes_allowed); 736 return nid; 737 } 738 739 /* 740 * returns the previously saved node ["this node"] from which to 741 * allocate a persistent huge page for the pool and advance the 742 * next node from which to allocate, handling wrap at end of node 743 * mask. 744 */ 745 static int hstate_next_node_to_alloc(struct hstate *h, 746 nodemask_t *nodes_allowed) 747 { 748 int nid; 749 750 VM_BUG_ON(!nodes_allowed); 751 752 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 753 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 754 755 return nid; 756 } 757 758 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 759 { 760 struct page *page; 761 int start_nid; 762 int next_nid; 763 int ret = 0; 764 765 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 766 next_nid = start_nid; 767 768 do { 769 page = alloc_fresh_huge_page_node(h, next_nid); 770 if (page) { 771 ret = 1; 772 break; 773 } 774 next_nid = hstate_next_node_to_alloc(h, nodes_allowed); 775 } while (next_nid != start_nid); 776 777 if (ret) 778 count_vm_event(HTLB_BUDDY_PGALLOC); 779 else 780 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 781 782 return ret; 783 } 784 785 /* 786 * helper for free_pool_huge_page() - return the previously saved 787 * node ["this node"] from which to free a huge page. Advance the 788 * next node id whether or not we find a free huge page to free so 789 * that the next attempt to free addresses the next node. 790 */ 791 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 792 { 793 int nid; 794 795 VM_BUG_ON(!nodes_allowed); 796 797 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 798 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 799 800 return nid; 801 } 802 803 /* 804 * Free huge page from pool from next node to free. 805 * Attempt to keep persistent huge pages more or less 806 * balanced over allowed nodes. 807 * Called with hugetlb_lock locked. 808 */ 809 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 810 bool acct_surplus) 811 { 812 int start_nid; 813 int next_nid; 814 int ret = 0; 815 816 start_nid = hstate_next_node_to_free(h, nodes_allowed); 817 next_nid = start_nid; 818 819 do { 820 /* 821 * If we're returning unused surplus pages, only examine 822 * nodes with surplus pages. 823 */ 824 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && 825 !list_empty(&h->hugepage_freelists[next_nid])) { 826 struct page *page = 827 list_entry(h->hugepage_freelists[next_nid].next, 828 struct page, lru); 829 list_del(&page->lru); 830 h->free_huge_pages--; 831 h->free_huge_pages_node[next_nid]--; 832 if (acct_surplus) { 833 h->surplus_huge_pages--; 834 h->surplus_huge_pages_node[next_nid]--; 835 } 836 update_and_free_page(h, page); 837 ret = 1; 838 break; 839 } 840 next_nid = hstate_next_node_to_free(h, nodes_allowed); 841 } while (next_nid != start_nid); 842 843 return ret; 844 } 845 846 static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) 847 { 848 struct page *page; 849 unsigned int r_nid; 850 851 if (h->order >= MAX_ORDER) 852 return NULL; 853 854 /* 855 * Assume we will successfully allocate the surplus page to 856 * prevent racing processes from causing the surplus to exceed 857 * overcommit 858 * 859 * This however introduces a different race, where a process B 860 * tries to grow the static hugepage pool while alloc_pages() is 861 * called by process A. B will only examine the per-node 862 * counters in determining if surplus huge pages can be 863 * converted to normal huge pages in adjust_pool_surplus(). A 864 * won't be able to increment the per-node counter, until the 865 * lock is dropped by B, but B doesn't drop hugetlb_lock until 866 * no more huge pages can be converted from surplus to normal 867 * state (and doesn't try to convert again). Thus, we have a 868 * case where a surplus huge page exists, the pool is grown, and 869 * the surplus huge page still exists after, even though it 870 * should just have been converted to a normal huge page. This 871 * does not leak memory, though, as the hugepage will be freed 872 * once it is out of use. It also does not allow the counters to 873 * go out of whack in adjust_pool_surplus() as we don't modify 874 * the node values until we've gotten the hugepage and only the 875 * per-node value is checked there. 876 */ 877 spin_lock(&hugetlb_lock); 878 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 879 spin_unlock(&hugetlb_lock); 880 return NULL; 881 } else { 882 h->nr_huge_pages++; 883 h->surplus_huge_pages++; 884 } 885 spin_unlock(&hugetlb_lock); 886 887 if (nid == NUMA_NO_NODE) 888 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 889 __GFP_REPEAT|__GFP_NOWARN, 890 huge_page_order(h)); 891 else 892 page = alloc_pages_exact_node(nid, 893 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 894 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); 895 896 if (page && arch_prepare_hugepage(page)) { 897 __free_pages(page, huge_page_order(h)); 898 page = NULL; 899 } 900 901 spin_lock(&hugetlb_lock); 902 if (page) { 903 INIT_LIST_HEAD(&page->lru); 904 r_nid = page_to_nid(page); 905 set_compound_page_dtor(page, free_huge_page); 906 set_hugetlb_cgroup(page, NULL); 907 /* 908 * We incremented the global counters already 909 */ 910 h->nr_huge_pages_node[r_nid]++; 911 h->surplus_huge_pages_node[r_nid]++; 912 __count_vm_event(HTLB_BUDDY_PGALLOC); 913 } else { 914 h->nr_huge_pages--; 915 h->surplus_huge_pages--; 916 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 917 } 918 spin_unlock(&hugetlb_lock); 919 920 return page; 921 } 922 923 /* 924 * This allocation function is useful in the context where vma is irrelevant. 925 * E.g. soft-offlining uses this function because it only cares physical 926 * address of error page. 927 */ 928 struct page *alloc_huge_page_node(struct hstate *h, int nid) 929 { 930 struct page *page; 931 932 spin_lock(&hugetlb_lock); 933 page = dequeue_huge_page_node(h, nid); 934 spin_unlock(&hugetlb_lock); 935 936 if (!page) 937 page = alloc_buddy_huge_page(h, nid); 938 939 return page; 940 } 941 942 /* 943 * Increase the hugetlb pool such that it can accommodate a reservation 944 * of size 'delta'. 945 */ 946 static int gather_surplus_pages(struct hstate *h, int delta) 947 { 948 struct list_head surplus_list; 949 struct page *page, *tmp; 950 int ret, i; 951 int needed, allocated; 952 bool alloc_ok = true; 953 954 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 955 if (needed <= 0) { 956 h->resv_huge_pages += delta; 957 return 0; 958 } 959 960 allocated = 0; 961 INIT_LIST_HEAD(&surplus_list); 962 963 ret = -ENOMEM; 964 retry: 965 spin_unlock(&hugetlb_lock); 966 for (i = 0; i < needed; i++) { 967 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 968 if (!page) { 969 alloc_ok = false; 970 break; 971 } 972 list_add(&page->lru, &surplus_list); 973 } 974 allocated += i; 975 976 /* 977 * After retaking hugetlb_lock, we need to recalculate 'needed' 978 * because either resv_huge_pages or free_huge_pages may have changed. 979 */ 980 spin_lock(&hugetlb_lock); 981 needed = (h->resv_huge_pages + delta) - 982 (h->free_huge_pages + allocated); 983 if (needed > 0) { 984 if (alloc_ok) 985 goto retry; 986 /* 987 * We were not able to allocate enough pages to 988 * satisfy the entire reservation so we free what 989 * we've allocated so far. 990 */ 991 goto free; 992 } 993 /* 994 * The surplus_list now contains _at_least_ the number of extra pages 995 * needed to accommodate the reservation. Add the appropriate number 996 * of pages to the hugetlb pool and free the extras back to the buddy 997 * allocator. Commit the entire reservation here to prevent another 998 * process from stealing the pages as they are added to the pool but 999 * before they are reserved. 1000 */ 1001 needed += allocated; 1002 h->resv_huge_pages += delta; 1003 ret = 0; 1004 1005 /* Free the needed pages to the hugetlb pool */ 1006 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1007 if ((--needed) < 0) 1008 break; 1009 /* 1010 * This page is now managed by the hugetlb allocator and has 1011 * no users -- drop the buddy allocator's reference. 1012 */ 1013 put_page_testzero(page); 1014 VM_BUG_ON(page_count(page)); 1015 enqueue_huge_page(h, page); 1016 } 1017 free: 1018 spin_unlock(&hugetlb_lock); 1019 1020 /* Free unnecessary surplus pages to the buddy allocator */ 1021 if (!list_empty(&surplus_list)) { 1022 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1023 put_page(page); 1024 } 1025 } 1026 spin_lock(&hugetlb_lock); 1027 1028 return ret; 1029 } 1030 1031 /* 1032 * When releasing a hugetlb pool reservation, any surplus pages that were 1033 * allocated to satisfy the reservation must be explicitly freed if they were 1034 * never used. 1035 * Called with hugetlb_lock held. 1036 */ 1037 static void return_unused_surplus_pages(struct hstate *h, 1038 unsigned long unused_resv_pages) 1039 { 1040 unsigned long nr_pages; 1041 1042 /* Uncommit the reservation */ 1043 h->resv_huge_pages -= unused_resv_pages; 1044 1045 /* Cannot return gigantic pages currently */ 1046 if (h->order >= MAX_ORDER) 1047 return; 1048 1049 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 1050 1051 /* 1052 * We want to release as many surplus pages as possible, spread 1053 * evenly across all nodes with memory. Iterate across these nodes 1054 * until we can no longer free unreserved surplus pages. This occurs 1055 * when the nodes with surplus pages have no free pages. 1056 * free_pool_huge_page() will balance the the freed pages across the 1057 * on-line nodes with memory and will handle the hstate accounting. 1058 */ 1059 while (nr_pages--) { 1060 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) 1061 break; 1062 } 1063 } 1064 1065 /* 1066 * Determine if the huge page at addr within the vma has an associated 1067 * reservation. Where it does not we will need to logically increase 1068 * reservation and actually increase subpool usage before an allocation 1069 * can occur. Where any new reservation would be required the 1070 * reservation change is prepared, but not committed. Once the page 1071 * has been allocated from the subpool and instantiated the change should 1072 * be committed via vma_commit_reservation. No action is required on 1073 * failure. 1074 */ 1075 static long vma_needs_reservation(struct hstate *h, 1076 struct vm_area_struct *vma, unsigned long addr) 1077 { 1078 struct address_space *mapping = vma->vm_file->f_mapping; 1079 struct inode *inode = mapping->host; 1080 1081 if (vma->vm_flags & VM_MAYSHARE) { 1082 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1083 return region_chg(&inode->i_mapping->private_list, 1084 idx, idx + 1); 1085 1086 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1087 return 1; 1088 1089 } else { 1090 long err; 1091 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1092 struct resv_map *reservations = vma_resv_map(vma); 1093 1094 err = region_chg(&reservations->regions, idx, idx + 1); 1095 if (err < 0) 1096 return err; 1097 return 0; 1098 } 1099 } 1100 static void vma_commit_reservation(struct hstate *h, 1101 struct vm_area_struct *vma, unsigned long addr) 1102 { 1103 struct address_space *mapping = vma->vm_file->f_mapping; 1104 struct inode *inode = mapping->host; 1105 1106 if (vma->vm_flags & VM_MAYSHARE) { 1107 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1108 region_add(&inode->i_mapping->private_list, idx, idx + 1); 1109 1110 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1111 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1112 struct resv_map *reservations = vma_resv_map(vma); 1113 1114 /* Mark this page used in the map. */ 1115 region_add(&reservations->regions, idx, idx + 1); 1116 } 1117 } 1118 1119 static struct page *alloc_huge_page(struct vm_area_struct *vma, 1120 unsigned long addr, int avoid_reserve) 1121 { 1122 struct hugepage_subpool *spool = subpool_vma(vma); 1123 struct hstate *h = hstate_vma(vma); 1124 struct page *page; 1125 long chg; 1126 int ret, idx; 1127 struct hugetlb_cgroup *h_cg; 1128 1129 idx = hstate_index(h); 1130 /* 1131 * Processes that did not create the mapping will have no 1132 * reserves and will not have accounted against subpool 1133 * limit. Check that the subpool limit can be made before 1134 * satisfying the allocation MAP_NORESERVE mappings may also 1135 * need pages and subpool limit allocated allocated if no reserve 1136 * mapping overlaps. 1137 */ 1138 chg = vma_needs_reservation(h, vma, addr); 1139 if (chg < 0) 1140 return ERR_PTR(-ENOMEM); 1141 if (chg) 1142 if (hugepage_subpool_get_pages(spool, chg)) 1143 return ERR_PTR(-ENOSPC); 1144 1145 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); 1146 if (ret) { 1147 hugepage_subpool_put_pages(spool, chg); 1148 return ERR_PTR(-ENOSPC); 1149 } 1150 spin_lock(&hugetlb_lock); 1151 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 1152 if (page) { 1153 /* update page cgroup details */ 1154 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), 1155 h_cg, page); 1156 spin_unlock(&hugetlb_lock); 1157 } else { 1158 spin_unlock(&hugetlb_lock); 1159 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1160 if (!page) { 1161 hugetlb_cgroup_uncharge_cgroup(idx, 1162 pages_per_huge_page(h), 1163 h_cg); 1164 hugepage_subpool_put_pages(spool, chg); 1165 return ERR_PTR(-ENOSPC); 1166 } 1167 spin_lock(&hugetlb_lock); 1168 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), 1169 h_cg, page); 1170 list_move(&page->lru, &h->hugepage_activelist); 1171 spin_unlock(&hugetlb_lock); 1172 } 1173 1174 set_page_private(page, (unsigned long)spool); 1175 1176 vma_commit_reservation(h, vma, addr); 1177 return page; 1178 } 1179 1180 int __weak alloc_bootmem_huge_page(struct hstate *h) 1181 { 1182 struct huge_bootmem_page *m; 1183 int nr_nodes = nodes_weight(node_states[N_MEMORY]); 1184 1185 while (nr_nodes) { 1186 void *addr; 1187 1188 addr = __alloc_bootmem_node_nopanic( 1189 NODE_DATA(hstate_next_node_to_alloc(h, 1190 &node_states[N_MEMORY])), 1191 huge_page_size(h), huge_page_size(h), 0); 1192 1193 if (addr) { 1194 /* 1195 * Use the beginning of the huge page to store the 1196 * huge_bootmem_page struct (until gather_bootmem 1197 * puts them into the mem_map). 1198 */ 1199 m = addr; 1200 goto found; 1201 } 1202 nr_nodes--; 1203 } 1204 return 0; 1205 1206 found: 1207 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1208 /* Put them into a private list first because mem_map is not up yet */ 1209 list_add(&m->list, &huge_boot_pages); 1210 m->hstate = h; 1211 return 1; 1212 } 1213 1214 static void prep_compound_huge_page(struct page *page, int order) 1215 { 1216 if (unlikely(order > (MAX_ORDER - 1))) 1217 prep_compound_gigantic_page(page, order); 1218 else 1219 prep_compound_page(page, order); 1220 } 1221 1222 /* Put bootmem huge pages into the standard lists after mem_map is up */ 1223 static void __init gather_bootmem_prealloc(void) 1224 { 1225 struct huge_bootmem_page *m; 1226 1227 list_for_each_entry(m, &huge_boot_pages, list) { 1228 struct hstate *h = m->hstate; 1229 struct page *page; 1230 1231 #ifdef CONFIG_HIGHMEM 1232 page = pfn_to_page(m->phys >> PAGE_SHIFT); 1233 free_bootmem_late((unsigned long)m, 1234 sizeof(struct huge_bootmem_page)); 1235 #else 1236 page = virt_to_page(m); 1237 #endif 1238 __ClearPageReserved(page); 1239 WARN_ON(page_count(page) != 1); 1240 prep_compound_huge_page(page, h->order); 1241 prep_new_huge_page(h, page, page_to_nid(page)); 1242 /* 1243 * If we had gigantic hugepages allocated at boot time, we need 1244 * to restore the 'stolen' pages to totalram_pages in order to 1245 * fix confusing memory reports from free(1) and another 1246 * side-effects, like CommitLimit going negative. 1247 */ 1248 if (h->order > (MAX_ORDER - 1)) 1249 totalram_pages += 1 << h->order; 1250 } 1251 } 1252 1253 static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1254 { 1255 unsigned long i; 1256 1257 for (i = 0; i < h->max_huge_pages; ++i) { 1258 if (h->order >= MAX_ORDER) { 1259 if (!alloc_bootmem_huge_page(h)) 1260 break; 1261 } else if (!alloc_fresh_huge_page(h, 1262 &node_states[N_MEMORY])) 1263 break; 1264 } 1265 h->max_huge_pages = i; 1266 } 1267 1268 static void __init hugetlb_init_hstates(void) 1269 { 1270 struct hstate *h; 1271 1272 for_each_hstate(h) { 1273 /* oversize hugepages were init'ed in early boot */ 1274 if (h->order < MAX_ORDER) 1275 hugetlb_hstate_alloc_pages(h); 1276 } 1277 } 1278 1279 static char * __init memfmt(char *buf, unsigned long n) 1280 { 1281 if (n >= (1UL << 30)) 1282 sprintf(buf, "%lu GB", n >> 30); 1283 else if (n >= (1UL << 20)) 1284 sprintf(buf, "%lu MB", n >> 20); 1285 else 1286 sprintf(buf, "%lu KB", n >> 10); 1287 return buf; 1288 } 1289 1290 static void __init report_hugepages(void) 1291 { 1292 struct hstate *h; 1293 1294 for_each_hstate(h) { 1295 char buf[32]; 1296 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", 1297 memfmt(buf, huge_page_size(h)), 1298 h->free_huge_pages); 1299 } 1300 } 1301 1302 #ifdef CONFIG_HIGHMEM 1303 static void try_to_free_low(struct hstate *h, unsigned long count, 1304 nodemask_t *nodes_allowed) 1305 { 1306 int i; 1307 1308 if (h->order >= MAX_ORDER) 1309 return; 1310 1311 for_each_node_mask(i, *nodes_allowed) { 1312 struct page *page, *next; 1313 struct list_head *freel = &h->hugepage_freelists[i]; 1314 list_for_each_entry_safe(page, next, freel, lru) { 1315 if (count >= h->nr_huge_pages) 1316 return; 1317 if (PageHighMem(page)) 1318 continue; 1319 list_del(&page->lru); 1320 update_and_free_page(h, page); 1321 h->free_huge_pages--; 1322 h->free_huge_pages_node[page_to_nid(page)]--; 1323 } 1324 } 1325 } 1326 #else 1327 static inline void try_to_free_low(struct hstate *h, unsigned long count, 1328 nodemask_t *nodes_allowed) 1329 { 1330 } 1331 #endif 1332 1333 /* 1334 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1335 * balanced by operating on them in a round-robin fashion. 1336 * Returns 1 if an adjustment was made. 1337 */ 1338 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1339 int delta) 1340 { 1341 int start_nid, next_nid; 1342 int ret = 0; 1343 1344 VM_BUG_ON(delta != -1 && delta != 1); 1345 1346 if (delta < 0) 1347 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 1348 else 1349 start_nid = hstate_next_node_to_free(h, nodes_allowed); 1350 next_nid = start_nid; 1351 1352 do { 1353 int nid = next_nid; 1354 if (delta < 0) { 1355 /* 1356 * To shrink on this node, there must be a surplus page 1357 */ 1358 if (!h->surplus_huge_pages_node[nid]) { 1359 next_nid = hstate_next_node_to_alloc(h, 1360 nodes_allowed); 1361 continue; 1362 } 1363 } 1364 if (delta > 0) { 1365 /* 1366 * Surplus cannot exceed the total number of pages 1367 */ 1368 if (h->surplus_huge_pages_node[nid] >= 1369 h->nr_huge_pages_node[nid]) { 1370 next_nid = hstate_next_node_to_free(h, 1371 nodes_allowed); 1372 continue; 1373 } 1374 } 1375 1376 h->surplus_huge_pages += delta; 1377 h->surplus_huge_pages_node[nid] += delta; 1378 ret = 1; 1379 break; 1380 } while (next_nid != start_nid); 1381 1382 return ret; 1383 } 1384 1385 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1386 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1387 nodemask_t *nodes_allowed) 1388 { 1389 unsigned long min_count, ret; 1390 1391 if (h->order >= MAX_ORDER) 1392 return h->max_huge_pages; 1393 1394 /* 1395 * Increase the pool size 1396 * First take pages out of surplus state. Then make up the 1397 * remaining difference by allocating fresh huge pages. 1398 * 1399 * We might race with alloc_buddy_huge_page() here and be unable 1400 * to convert a surplus huge page to a normal huge page. That is 1401 * not critical, though, it just means the overall size of the 1402 * pool might be one hugepage larger than it needs to be, but 1403 * within all the constraints specified by the sysctls. 1404 */ 1405 spin_lock(&hugetlb_lock); 1406 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1407 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1408 break; 1409 } 1410 1411 while (count > persistent_huge_pages(h)) { 1412 /* 1413 * If this allocation races such that we no longer need the 1414 * page, free_huge_page will handle it by freeing the page 1415 * and reducing the surplus. 1416 */ 1417 spin_unlock(&hugetlb_lock); 1418 ret = alloc_fresh_huge_page(h, nodes_allowed); 1419 spin_lock(&hugetlb_lock); 1420 if (!ret) 1421 goto out; 1422 1423 /* Bail for signals. Probably ctrl-c from user */ 1424 if (signal_pending(current)) 1425 goto out; 1426 } 1427 1428 /* 1429 * Decrease the pool size 1430 * First return free pages to the buddy allocator (being careful 1431 * to keep enough around to satisfy reservations). Then place 1432 * pages into surplus state as needed so the pool will shrink 1433 * to the desired size as pages become free. 1434 * 1435 * By placing pages into the surplus state independent of the 1436 * overcommit value, we are allowing the surplus pool size to 1437 * exceed overcommit. There are few sane options here. Since 1438 * alloc_buddy_huge_page() is checking the global counter, 1439 * though, we'll note that we're not allowed to exceed surplus 1440 * and won't grow the pool anywhere else. Not until one of the 1441 * sysctls are changed, or the surplus pages go out of use. 1442 */ 1443 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1444 min_count = max(count, min_count); 1445 try_to_free_low(h, min_count, nodes_allowed); 1446 while (min_count < persistent_huge_pages(h)) { 1447 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1448 break; 1449 } 1450 while (count < persistent_huge_pages(h)) { 1451 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1452 break; 1453 } 1454 out: 1455 ret = persistent_huge_pages(h); 1456 spin_unlock(&hugetlb_lock); 1457 return ret; 1458 } 1459 1460 #define HSTATE_ATTR_RO(_name) \ 1461 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1462 1463 #define HSTATE_ATTR(_name) \ 1464 static struct kobj_attribute _name##_attr = \ 1465 __ATTR(_name, 0644, _name##_show, _name##_store) 1466 1467 static struct kobject *hugepages_kobj; 1468 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1469 1470 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1471 1472 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1473 { 1474 int i; 1475 1476 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1477 if (hstate_kobjs[i] == kobj) { 1478 if (nidp) 1479 *nidp = NUMA_NO_NODE; 1480 return &hstates[i]; 1481 } 1482 1483 return kobj_to_node_hstate(kobj, nidp); 1484 } 1485 1486 static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1487 struct kobj_attribute *attr, char *buf) 1488 { 1489 struct hstate *h; 1490 unsigned long nr_huge_pages; 1491 int nid; 1492 1493 h = kobj_to_hstate(kobj, &nid); 1494 if (nid == NUMA_NO_NODE) 1495 nr_huge_pages = h->nr_huge_pages; 1496 else 1497 nr_huge_pages = h->nr_huge_pages_node[nid]; 1498 1499 return sprintf(buf, "%lu\n", nr_huge_pages); 1500 } 1501 1502 static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1503 struct kobject *kobj, struct kobj_attribute *attr, 1504 const char *buf, size_t len) 1505 { 1506 int err; 1507 int nid; 1508 unsigned long count; 1509 struct hstate *h; 1510 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1511 1512 err = strict_strtoul(buf, 10, &count); 1513 if (err) 1514 goto out; 1515 1516 h = kobj_to_hstate(kobj, &nid); 1517 if (h->order >= MAX_ORDER) { 1518 err = -EINVAL; 1519 goto out; 1520 } 1521 1522 if (nid == NUMA_NO_NODE) { 1523 /* 1524 * global hstate attribute 1525 */ 1526 if (!(obey_mempolicy && 1527 init_nodemask_of_mempolicy(nodes_allowed))) { 1528 NODEMASK_FREE(nodes_allowed); 1529 nodes_allowed = &node_states[N_MEMORY]; 1530 } 1531 } else if (nodes_allowed) { 1532 /* 1533 * per node hstate attribute: adjust count to global, 1534 * but restrict alloc/free to the specified node. 1535 */ 1536 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1537 init_nodemask_of_node(nodes_allowed, nid); 1538 } else 1539 nodes_allowed = &node_states[N_MEMORY]; 1540 1541 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1542 1543 if (nodes_allowed != &node_states[N_MEMORY]) 1544 NODEMASK_FREE(nodes_allowed); 1545 1546 return len; 1547 out: 1548 NODEMASK_FREE(nodes_allowed); 1549 return err; 1550 } 1551 1552 static ssize_t nr_hugepages_show(struct kobject *kobj, 1553 struct kobj_attribute *attr, char *buf) 1554 { 1555 return nr_hugepages_show_common(kobj, attr, buf); 1556 } 1557 1558 static ssize_t nr_hugepages_store(struct kobject *kobj, 1559 struct kobj_attribute *attr, const char *buf, size_t len) 1560 { 1561 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1562 } 1563 HSTATE_ATTR(nr_hugepages); 1564 1565 #ifdef CONFIG_NUMA 1566 1567 /* 1568 * hstate attribute for optionally mempolicy-based constraint on persistent 1569 * huge page alloc/free. 1570 */ 1571 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1572 struct kobj_attribute *attr, char *buf) 1573 { 1574 return nr_hugepages_show_common(kobj, attr, buf); 1575 } 1576 1577 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1578 struct kobj_attribute *attr, const char *buf, size_t len) 1579 { 1580 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1581 } 1582 HSTATE_ATTR(nr_hugepages_mempolicy); 1583 #endif 1584 1585 1586 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1587 struct kobj_attribute *attr, char *buf) 1588 { 1589 struct hstate *h = kobj_to_hstate(kobj, NULL); 1590 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1591 } 1592 1593 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1594 struct kobj_attribute *attr, const char *buf, size_t count) 1595 { 1596 int err; 1597 unsigned long input; 1598 struct hstate *h = kobj_to_hstate(kobj, NULL); 1599 1600 if (h->order >= MAX_ORDER) 1601 return -EINVAL; 1602 1603 err = strict_strtoul(buf, 10, &input); 1604 if (err) 1605 return err; 1606 1607 spin_lock(&hugetlb_lock); 1608 h->nr_overcommit_huge_pages = input; 1609 spin_unlock(&hugetlb_lock); 1610 1611 return count; 1612 } 1613 HSTATE_ATTR(nr_overcommit_hugepages); 1614 1615 static ssize_t free_hugepages_show(struct kobject *kobj, 1616 struct kobj_attribute *attr, char *buf) 1617 { 1618 struct hstate *h; 1619 unsigned long free_huge_pages; 1620 int nid; 1621 1622 h = kobj_to_hstate(kobj, &nid); 1623 if (nid == NUMA_NO_NODE) 1624 free_huge_pages = h->free_huge_pages; 1625 else 1626 free_huge_pages = h->free_huge_pages_node[nid]; 1627 1628 return sprintf(buf, "%lu\n", free_huge_pages); 1629 } 1630 HSTATE_ATTR_RO(free_hugepages); 1631 1632 static ssize_t resv_hugepages_show(struct kobject *kobj, 1633 struct kobj_attribute *attr, char *buf) 1634 { 1635 struct hstate *h = kobj_to_hstate(kobj, NULL); 1636 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1637 } 1638 HSTATE_ATTR_RO(resv_hugepages); 1639 1640 static ssize_t surplus_hugepages_show(struct kobject *kobj, 1641 struct kobj_attribute *attr, char *buf) 1642 { 1643 struct hstate *h; 1644 unsigned long surplus_huge_pages; 1645 int nid; 1646 1647 h = kobj_to_hstate(kobj, &nid); 1648 if (nid == NUMA_NO_NODE) 1649 surplus_huge_pages = h->surplus_huge_pages; 1650 else 1651 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1652 1653 return sprintf(buf, "%lu\n", surplus_huge_pages); 1654 } 1655 HSTATE_ATTR_RO(surplus_hugepages); 1656 1657 static struct attribute *hstate_attrs[] = { 1658 &nr_hugepages_attr.attr, 1659 &nr_overcommit_hugepages_attr.attr, 1660 &free_hugepages_attr.attr, 1661 &resv_hugepages_attr.attr, 1662 &surplus_hugepages_attr.attr, 1663 #ifdef CONFIG_NUMA 1664 &nr_hugepages_mempolicy_attr.attr, 1665 #endif 1666 NULL, 1667 }; 1668 1669 static struct attribute_group hstate_attr_group = { 1670 .attrs = hstate_attrs, 1671 }; 1672 1673 static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, 1674 struct kobject **hstate_kobjs, 1675 struct attribute_group *hstate_attr_group) 1676 { 1677 int retval; 1678 int hi = hstate_index(h); 1679 1680 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1681 if (!hstate_kobjs[hi]) 1682 return -ENOMEM; 1683 1684 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1685 if (retval) 1686 kobject_put(hstate_kobjs[hi]); 1687 1688 return retval; 1689 } 1690 1691 static void __init hugetlb_sysfs_init(void) 1692 { 1693 struct hstate *h; 1694 int err; 1695 1696 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1697 if (!hugepages_kobj) 1698 return; 1699 1700 for_each_hstate(h) { 1701 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1702 hstate_kobjs, &hstate_attr_group); 1703 if (err) 1704 pr_err("Hugetlb: Unable to add hstate %s", h->name); 1705 } 1706 } 1707 1708 #ifdef CONFIG_NUMA 1709 1710 /* 1711 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1712 * with node devices in node_devices[] using a parallel array. The array 1713 * index of a node device or _hstate == node id. 1714 * This is here to avoid any static dependency of the node device driver, in 1715 * the base kernel, on the hugetlb module. 1716 */ 1717 struct node_hstate { 1718 struct kobject *hugepages_kobj; 1719 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1720 }; 1721 struct node_hstate node_hstates[MAX_NUMNODES]; 1722 1723 /* 1724 * A subset of global hstate attributes for node devices 1725 */ 1726 static struct attribute *per_node_hstate_attrs[] = { 1727 &nr_hugepages_attr.attr, 1728 &free_hugepages_attr.attr, 1729 &surplus_hugepages_attr.attr, 1730 NULL, 1731 }; 1732 1733 static struct attribute_group per_node_hstate_attr_group = { 1734 .attrs = per_node_hstate_attrs, 1735 }; 1736 1737 /* 1738 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. 1739 * Returns node id via non-NULL nidp. 1740 */ 1741 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1742 { 1743 int nid; 1744 1745 for (nid = 0; nid < nr_node_ids; nid++) { 1746 struct node_hstate *nhs = &node_hstates[nid]; 1747 int i; 1748 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1749 if (nhs->hstate_kobjs[i] == kobj) { 1750 if (nidp) 1751 *nidp = nid; 1752 return &hstates[i]; 1753 } 1754 } 1755 1756 BUG(); 1757 return NULL; 1758 } 1759 1760 /* 1761 * Unregister hstate attributes from a single node device. 1762 * No-op if no hstate attributes attached. 1763 */ 1764 void hugetlb_unregister_node(struct node *node) 1765 { 1766 struct hstate *h; 1767 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1768 1769 if (!nhs->hugepages_kobj) 1770 return; /* no hstate attributes */ 1771 1772 for_each_hstate(h) { 1773 int idx = hstate_index(h); 1774 if (nhs->hstate_kobjs[idx]) { 1775 kobject_put(nhs->hstate_kobjs[idx]); 1776 nhs->hstate_kobjs[idx] = NULL; 1777 } 1778 } 1779 1780 kobject_put(nhs->hugepages_kobj); 1781 nhs->hugepages_kobj = NULL; 1782 } 1783 1784 /* 1785 * hugetlb module exit: unregister hstate attributes from node devices 1786 * that have them. 1787 */ 1788 static void hugetlb_unregister_all_nodes(void) 1789 { 1790 int nid; 1791 1792 /* 1793 * disable node device registrations. 1794 */ 1795 register_hugetlbfs_with_node(NULL, NULL); 1796 1797 /* 1798 * remove hstate attributes from any nodes that have them. 1799 */ 1800 for (nid = 0; nid < nr_node_ids; nid++) 1801 hugetlb_unregister_node(node_devices[nid]); 1802 } 1803 1804 /* 1805 * Register hstate attributes for a single node device. 1806 * No-op if attributes already registered. 1807 */ 1808 void hugetlb_register_node(struct node *node) 1809 { 1810 struct hstate *h; 1811 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1812 int err; 1813 1814 if (nhs->hugepages_kobj) 1815 return; /* already allocated */ 1816 1817 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1818 &node->dev.kobj); 1819 if (!nhs->hugepages_kobj) 1820 return; 1821 1822 for_each_hstate(h) { 1823 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1824 nhs->hstate_kobjs, 1825 &per_node_hstate_attr_group); 1826 if (err) { 1827 pr_err("Hugetlb: Unable to add hstate %s for node %d\n", 1828 h->name, node->dev.id); 1829 hugetlb_unregister_node(node); 1830 break; 1831 } 1832 } 1833 } 1834 1835 /* 1836 * hugetlb init time: register hstate attributes for all registered node 1837 * devices of nodes that have memory. All on-line nodes should have 1838 * registered their associated device by this time. 1839 */ 1840 static void hugetlb_register_all_nodes(void) 1841 { 1842 int nid; 1843 1844 for_each_node_state(nid, N_MEMORY) { 1845 struct node *node = node_devices[nid]; 1846 if (node->dev.id == nid) 1847 hugetlb_register_node(node); 1848 } 1849 1850 /* 1851 * Let the node device driver know we're here so it can 1852 * [un]register hstate attributes on node hotplug. 1853 */ 1854 register_hugetlbfs_with_node(hugetlb_register_node, 1855 hugetlb_unregister_node); 1856 } 1857 #else /* !CONFIG_NUMA */ 1858 1859 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1860 { 1861 BUG(); 1862 if (nidp) 1863 *nidp = -1; 1864 return NULL; 1865 } 1866 1867 static void hugetlb_unregister_all_nodes(void) { } 1868 1869 static void hugetlb_register_all_nodes(void) { } 1870 1871 #endif 1872 1873 static void __exit hugetlb_exit(void) 1874 { 1875 struct hstate *h; 1876 1877 hugetlb_unregister_all_nodes(); 1878 1879 for_each_hstate(h) { 1880 kobject_put(hstate_kobjs[hstate_index(h)]); 1881 } 1882 1883 kobject_put(hugepages_kobj); 1884 } 1885 module_exit(hugetlb_exit); 1886 1887 static int __init hugetlb_init(void) 1888 { 1889 /* Some platform decide whether they support huge pages at boot 1890 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1891 * there is no such support 1892 */ 1893 if (HPAGE_SHIFT == 0) 1894 return 0; 1895 1896 if (!size_to_hstate(default_hstate_size)) { 1897 default_hstate_size = HPAGE_SIZE; 1898 if (!size_to_hstate(default_hstate_size)) 1899 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1900 } 1901 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); 1902 if (default_hstate_max_huge_pages) 1903 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1904 1905 hugetlb_init_hstates(); 1906 gather_bootmem_prealloc(); 1907 report_hugepages(); 1908 1909 hugetlb_sysfs_init(); 1910 hugetlb_register_all_nodes(); 1911 hugetlb_cgroup_file_init(); 1912 1913 return 0; 1914 } 1915 module_init(hugetlb_init); 1916 1917 /* Should be called on processing a hugepagesz=... option */ 1918 void __init hugetlb_add_hstate(unsigned order) 1919 { 1920 struct hstate *h; 1921 unsigned long i; 1922 1923 if (size_to_hstate(PAGE_SIZE << order)) { 1924 pr_warning("hugepagesz= specified twice, ignoring\n"); 1925 return; 1926 } 1927 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); 1928 BUG_ON(order == 0); 1929 h = &hstates[hugetlb_max_hstate++]; 1930 h->order = order; 1931 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1932 h->nr_huge_pages = 0; 1933 h->free_huge_pages = 0; 1934 for (i = 0; i < MAX_NUMNODES; ++i) 1935 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1936 INIT_LIST_HEAD(&h->hugepage_activelist); 1937 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); 1938 h->next_nid_to_free = first_node(node_states[N_MEMORY]); 1939 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1940 huge_page_size(h)/1024); 1941 1942 parsed_hstate = h; 1943 } 1944 1945 static int __init hugetlb_nrpages_setup(char *s) 1946 { 1947 unsigned long *mhp; 1948 static unsigned long *last_mhp; 1949 1950 /* 1951 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, 1952 * so this hugepages= parameter goes to the "default hstate". 1953 */ 1954 if (!hugetlb_max_hstate) 1955 mhp = &default_hstate_max_huge_pages; 1956 else 1957 mhp = &parsed_hstate->max_huge_pages; 1958 1959 if (mhp == last_mhp) { 1960 pr_warning("hugepages= specified twice without " 1961 "interleaving hugepagesz=, ignoring\n"); 1962 return 1; 1963 } 1964 1965 if (sscanf(s, "%lu", mhp) <= 0) 1966 *mhp = 0; 1967 1968 /* 1969 * Global state is always initialized later in hugetlb_init. 1970 * But we need to allocate >= MAX_ORDER hstates here early to still 1971 * use the bootmem allocator. 1972 */ 1973 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) 1974 hugetlb_hstate_alloc_pages(parsed_hstate); 1975 1976 last_mhp = mhp; 1977 1978 return 1; 1979 } 1980 __setup("hugepages=", hugetlb_nrpages_setup); 1981 1982 static int __init hugetlb_default_setup(char *s) 1983 { 1984 default_hstate_size = memparse(s, &s); 1985 return 1; 1986 } 1987 __setup("default_hugepagesz=", hugetlb_default_setup); 1988 1989 static unsigned int cpuset_mems_nr(unsigned int *array) 1990 { 1991 int node; 1992 unsigned int nr = 0; 1993 1994 for_each_node_mask(node, cpuset_current_mems_allowed) 1995 nr += array[node]; 1996 1997 return nr; 1998 } 1999 2000 #ifdef CONFIG_SYSCTL 2001 static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 2002 struct ctl_table *table, int write, 2003 void __user *buffer, size_t *length, loff_t *ppos) 2004 { 2005 struct hstate *h = &default_hstate; 2006 unsigned long tmp; 2007 int ret; 2008 2009 tmp = h->max_huge_pages; 2010 2011 if (write && h->order >= MAX_ORDER) 2012 return -EINVAL; 2013 2014 table->data = &tmp; 2015 table->maxlen = sizeof(unsigned long); 2016 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2017 if (ret) 2018 goto out; 2019 2020 if (write) { 2021 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 2022 GFP_KERNEL | __GFP_NORETRY); 2023 if (!(obey_mempolicy && 2024 init_nodemask_of_mempolicy(nodes_allowed))) { 2025 NODEMASK_FREE(nodes_allowed); 2026 nodes_allowed = &node_states[N_MEMORY]; 2027 } 2028 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 2029 2030 if (nodes_allowed != &node_states[N_MEMORY]) 2031 NODEMASK_FREE(nodes_allowed); 2032 } 2033 out: 2034 return ret; 2035 } 2036 2037 int hugetlb_sysctl_handler(struct ctl_table *table, int write, 2038 void __user *buffer, size_t *length, loff_t *ppos) 2039 { 2040 2041 return hugetlb_sysctl_handler_common(false, table, write, 2042 buffer, length, ppos); 2043 } 2044 2045 #ifdef CONFIG_NUMA 2046 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 2047 void __user *buffer, size_t *length, loff_t *ppos) 2048 { 2049 return hugetlb_sysctl_handler_common(true, table, write, 2050 buffer, length, ppos); 2051 } 2052 #endif /* CONFIG_NUMA */ 2053 2054 int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 2055 void __user *buffer, 2056 size_t *length, loff_t *ppos) 2057 { 2058 proc_dointvec(table, write, buffer, length, ppos); 2059 if (hugepages_treat_as_movable) 2060 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 2061 else 2062 htlb_alloc_mask = GFP_HIGHUSER; 2063 return 0; 2064 } 2065 2066 int hugetlb_overcommit_handler(struct ctl_table *table, int write, 2067 void __user *buffer, 2068 size_t *length, loff_t *ppos) 2069 { 2070 struct hstate *h = &default_hstate; 2071 unsigned long tmp; 2072 int ret; 2073 2074 tmp = h->nr_overcommit_huge_pages; 2075 2076 if (write && h->order >= MAX_ORDER) 2077 return -EINVAL; 2078 2079 table->data = &tmp; 2080 table->maxlen = sizeof(unsigned long); 2081 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2082 if (ret) 2083 goto out; 2084 2085 if (write) { 2086 spin_lock(&hugetlb_lock); 2087 h->nr_overcommit_huge_pages = tmp; 2088 spin_unlock(&hugetlb_lock); 2089 } 2090 out: 2091 return ret; 2092 } 2093 2094 #endif /* CONFIG_SYSCTL */ 2095 2096 void hugetlb_report_meminfo(struct seq_file *m) 2097 { 2098 struct hstate *h = &default_hstate; 2099 seq_printf(m, 2100 "HugePages_Total: %5lu\n" 2101 "HugePages_Free: %5lu\n" 2102 "HugePages_Rsvd: %5lu\n" 2103 "HugePages_Surp: %5lu\n" 2104 "Hugepagesize: %8lu kB\n", 2105 h->nr_huge_pages, 2106 h->free_huge_pages, 2107 h->resv_huge_pages, 2108 h->surplus_huge_pages, 2109 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2110 } 2111 2112 int hugetlb_report_node_meminfo(int nid, char *buf) 2113 { 2114 struct hstate *h = &default_hstate; 2115 return sprintf(buf, 2116 "Node %d HugePages_Total: %5u\n" 2117 "Node %d HugePages_Free: %5u\n" 2118 "Node %d HugePages_Surp: %5u\n", 2119 nid, h->nr_huge_pages_node[nid], 2120 nid, h->free_huge_pages_node[nid], 2121 nid, h->surplus_huge_pages_node[nid]); 2122 } 2123 2124 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 2125 unsigned long hugetlb_total_pages(void) 2126 { 2127 struct hstate *h = &default_hstate; 2128 return h->nr_huge_pages * pages_per_huge_page(h); 2129 } 2130 2131 static int hugetlb_acct_memory(struct hstate *h, long delta) 2132 { 2133 int ret = -ENOMEM; 2134 2135 spin_lock(&hugetlb_lock); 2136 /* 2137 * When cpuset is configured, it breaks the strict hugetlb page 2138 * reservation as the accounting is done on a global variable. Such 2139 * reservation is completely rubbish in the presence of cpuset because 2140 * the reservation is not checked against page availability for the 2141 * current cpuset. Application can still potentially OOM'ed by kernel 2142 * with lack of free htlb page in cpuset that the task is in. 2143 * Attempt to enforce strict accounting with cpuset is almost 2144 * impossible (or too ugly) because cpuset is too fluid that 2145 * task or memory node can be dynamically moved between cpusets. 2146 * 2147 * The change of semantics for shared hugetlb mapping with cpuset is 2148 * undesirable. However, in order to preserve some of the semantics, 2149 * we fall back to check against current free page availability as 2150 * a best attempt and hopefully to minimize the impact of changing 2151 * semantics that cpuset has. 2152 */ 2153 if (delta > 0) { 2154 if (gather_surplus_pages(h, delta) < 0) 2155 goto out; 2156 2157 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 2158 return_unused_surplus_pages(h, delta); 2159 goto out; 2160 } 2161 } 2162 2163 ret = 0; 2164 if (delta < 0) 2165 return_unused_surplus_pages(h, (unsigned long) -delta); 2166 2167 out: 2168 spin_unlock(&hugetlb_lock); 2169 return ret; 2170 } 2171 2172 static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2173 { 2174 struct resv_map *reservations = vma_resv_map(vma); 2175 2176 /* 2177 * This new VMA should share its siblings reservation map if present. 2178 * The VMA will only ever have a valid reservation map pointer where 2179 * it is being copied for another still existing VMA. As that VMA 2180 * has a reference to the reservation map it cannot disappear until 2181 * after this open call completes. It is therefore safe to take a 2182 * new reference here without additional locking. 2183 */ 2184 if (reservations) 2185 kref_get(&reservations->refs); 2186 } 2187 2188 static void resv_map_put(struct vm_area_struct *vma) 2189 { 2190 struct resv_map *reservations = vma_resv_map(vma); 2191 2192 if (!reservations) 2193 return; 2194 kref_put(&reservations->refs, resv_map_release); 2195 } 2196 2197 static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2198 { 2199 struct hstate *h = hstate_vma(vma); 2200 struct resv_map *reservations = vma_resv_map(vma); 2201 struct hugepage_subpool *spool = subpool_vma(vma); 2202 unsigned long reserve; 2203 unsigned long start; 2204 unsigned long end; 2205 2206 if (reservations) { 2207 start = vma_hugecache_offset(h, vma, vma->vm_start); 2208 end = vma_hugecache_offset(h, vma, vma->vm_end); 2209 2210 reserve = (end - start) - 2211 region_count(&reservations->regions, start, end); 2212 2213 resv_map_put(vma); 2214 2215 if (reserve) { 2216 hugetlb_acct_memory(h, -reserve); 2217 hugepage_subpool_put_pages(spool, reserve); 2218 } 2219 } 2220 } 2221 2222 /* 2223 * We cannot handle pagefaults against hugetlb pages at all. They cause 2224 * handle_mm_fault() to try to instantiate regular-sized pages in the 2225 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2226 * this far. 2227 */ 2228 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2229 { 2230 BUG(); 2231 return 0; 2232 } 2233 2234 const struct vm_operations_struct hugetlb_vm_ops = { 2235 .fault = hugetlb_vm_op_fault, 2236 .open = hugetlb_vm_op_open, 2237 .close = hugetlb_vm_op_close, 2238 }; 2239 2240 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2241 int writable) 2242 { 2243 pte_t entry; 2244 2245 if (writable) { 2246 entry = 2247 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 2248 } else { 2249 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 2250 } 2251 entry = pte_mkyoung(entry); 2252 entry = pte_mkhuge(entry); 2253 entry = arch_make_huge_pte(entry, vma, page, writable); 2254 2255 return entry; 2256 } 2257 2258 static void set_huge_ptep_writable(struct vm_area_struct *vma, 2259 unsigned long address, pte_t *ptep) 2260 { 2261 pte_t entry; 2262 2263 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 2264 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) 2265 update_mmu_cache(vma, address, ptep); 2266 } 2267 2268 2269 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2270 struct vm_area_struct *vma) 2271 { 2272 pte_t *src_pte, *dst_pte, entry; 2273 struct page *ptepage; 2274 unsigned long addr; 2275 int cow; 2276 struct hstate *h = hstate_vma(vma); 2277 unsigned long sz = huge_page_size(h); 2278 2279 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2280 2281 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2282 src_pte = huge_pte_offset(src, addr); 2283 if (!src_pte) 2284 continue; 2285 dst_pte = huge_pte_alloc(dst, addr, sz); 2286 if (!dst_pte) 2287 goto nomem; 2288 2289 /* If the pagetables are shared don't copy or take references */ 2290 if (dst_pte == src_pte) 2291 continue; 2292 2293 spin_lock(&dst->page_table_lock); 2294 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 2295 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2296 if (cow) 2297 huge_ptep_set_wrprotect(src, addr, src_pte); 2298 entry = huge_ptep_get(src_pte); 2299 ptepage = pte_page(entry); 2300 get_page(ptepage); 2301 page_dup_rmap(ptepage); 2302 set_huge_pte_at(dst, addr, dst_pte, entry); 2303 } 2304 spin_unlock(&src->page_table_lock); 2305 spin_unlock(&dst->page_table_lock); 2306 } 2307 return 0; 2308 2309 nomem: 2310 return -ENOMEM; 2311 } 2312 2313 static int is_hugetlb_entry_migration(pte_t pte) 2314 { 2315 swp_entry_t swp; 2316 2317 if (huge_pte_none(pte) || pte_present(pte)) 2318 return 0; 2319 swp = pte_to_swp_entry(pte); 2320 if (non_swap_entry(swp) && is_migration_entry(swp)) 2321 return 1; 2322 else 2323 return 0; 2324 } 2325 2326 static int is_hugetlb_entry_hwpoisoned(pte_t pte) 2327 { 2328 swp_entry_t swp; 2329 2330 if (huge_pte_none(pte) || pte_present(pte)) 2331 return 0; 2332 swp = pte_to_swp_entry(pte); 2333 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) 2334 return 1; 2335 else 2336 return 0; 2337 } 2338 2339 void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 2340 unsigned long start, unsigned long end, 2341 struct page *ref_page) 2342 { 2343 int force_flush = 0; 2344 struct mm_struct *mm = vma->vm_mm; 2345 unsigned long address; 2346 pte_t *ptep; 2347 pte_t pte; 2348 struct page *page; 2349 struct hstate *h = hstate_vma(vma); 2350 unsigned long sz = huge_page_size(h); 2351 const unsigned long mmun_start = start; /* For mmu_notifiers */ 2352 const unsigned long mmun_end = end; /* For mmu_notifiers */ 2353 2354 WARN_ON(!is_vm_hugetlb_page(vma)); 2355 BUG_ON(start & ~huge_page_mask(h)); 2356 BUG_ON(end & ~huge_page_mask(h)); 2357 2358 tlb_start_vma(tlb, vma); 2359 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2360 again: 2361 spin_lock(&mm->page_table_lock); 2362 for (address = start; address < end; address += sz) { 2363 ptep = huge_pte_offset(mm, address); 2364 if (!ptep) 2365 continue; 2366 2367 if (huge_pmd_unshare(mm, &address, ptep)) 2368 continue; 2369 2370 pte = huge_ptep_get(ptep); 2371 if (huge_pte_none(pte)) 2372 continue; 2373 2374 /* 2375 * HWPoisoned hugepage is already unmapped and dropped reference 2376 */ 2377 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { 2378 pte_clear(mm, address, ptep); 2379 continue; 2380 } 2381 2382 page = pte_page(pte); 2383 /* 2384 * If a reference page is supplied, it is because a specific 2385 * page is being unmapped, not a range. Ensure the page we 2386 * are about to unmap is the actual page of interest. 2387 */ 2388 if (ref_page) { 2389 if (page != ref_page) 2390 continue; 2391 2392 /* 2393 * Mark the VMA as having unmapped its page so that 2394 * future faults in this VMA will fail rather than 2395 * looking like data was lost 2396 */ 2397 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2398 } 2399 2400 pte = huge_ptep_get_and_clear(mm, address, ptep); 2401 tlb_remove_tlb_entry(tlb, ptep, address); 2402 if (pte_dirty(pte)) 2403 set_page_dirty(page); 2404 2405 page_remove_rmap(page); 2406 force_flush = !__tlb_remove_page(tlb, page); 2407 if (force_flush) 2408 break; 2409 /* Bail out after unmapping reference page if supplied */ 2410 if (ref_page) 2411 break; 2412 } 2413 spin_unlock(&mm->page_table_lock); 2414 /* 2415 * mmu_gather ran out of room to batch pages, we break out of 2416 * the PTE lock to avoid doing the potential expensive TLB invalidate 2417 * and page-free while holding it. 2418 */ 2419 if (force_flush) { 2420 force_flush = 0; 2421 tlb_flush_mmu(tlb); 2422 if (address < end && !ref_page) 2423 goto again; 2424 } 2425 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2426 tlb_end_vma(tlb, vma); 2427 } 2428 2429 void __unmap_hugepage_range_final(struct mmu_gather *tlb, 2430 struct vm_area_struct *vma, unsigned long start, 2431 unsigned long end, struct page *ref_page) 2432 { 2433 __unmap_hugepage_range(tlb, vma, start, end, ref_page); 2434 2435 /* 2436 * Clear this flag so that x86's huge_pmd_share page_table_shareable 2437 * test will fail on a vma being torn down, and not grab a page table 2438 * on its way out. We're lucky that the flag has such an appropriate 2439 * name, and can in fact be safely cleared here. We could clear it 2440 * before the __unmap_hugepage_range above, but all that's necessary 2441 * is to clear it before releasing the i_mmap_mutex. This works 2442 * because in the context this is called, the VMA is about to be 2443 * destroyed and the i_mmap_mutex is held. 2444 */ 2445 vma->vm_flags &= ~VM_MAYSHARE; 2446 } 2447 2448 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2449 unsigned long end, struct page *ref_page) 2450 { 2451 struct mm_struct *mm; 2452 struct mmu_gather tlb; 2453 2454 mm = vma->vm_mm; 2455 2456 tlb_gather_mmu(&tlb, mm, 0); 2457 __unmap_hugepage_range(&tlb, vma, start, end, ref_page); 2458 tlb_finish_mmu(&tlb, start, end); 2459 } 2460 2461 /* 2462 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2463 * mappping it owns the reserve page for. The intention is to unmap the page 2464 * from other VMAs and let the children be SIGKILLed if they are faulting the 2465 * same region. 2466 */ 2467 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2468 struct page *page, unsigned long address) 2469 { 2470 struct hstate *h = hstate_vma(vma); 2471 struct vm_area_struct *iter_vma; 2472 struct address_space *mapping; 2473 pgoff_t pgoff; 2474 2475 /* 2476 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2477 * from page cache lookup which is in HPAGE_SIZE units. 2478 */ 2479 address = address & huge_page_mask(h); 2480 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + 2481 vma->vm_pgoff; 2482 mapping = file_inode(vma->vm_file)->i_mapping; 2483 2484 /* 2485 * Take the mapping lock for the duration of the table walk. As 2486 * this mapping should be shared between all the VMAs, 2487 * __unmap_hugepage_range() is called as the lock is already held 2488 */ 2489 mutex_lock(&mapping->i_mmap_mutex); 2490 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { 2491 /* Do not unmap the current VMA */ 2492 if (iter_vma == vma) 2493 continue; 2494 2495 /* 2496 * Unmap the page from other VMAs without their own reserves. 2497 * They get marked to be SIGKILLed if they fault in these 2498 * areas. This is because a future no-page fault on this VMA 2499 * could insert a zeroed page instead of the data existing 2500 * from the time of fork. This would look like data corruption 2501 */ 2502 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2503 unmap_hugepage_range(iter_vma, address, 2504 address + huge_page_size(h), page); 2505 } 2506 mutex_unlock(&mapping->i_mmap_mutex); 2507 2508 return 1; 2509 } 2510 2511 /* 2512 * Hugetlb_cow() should be called with page lock of the original hugepage held. 2513 * Called with hugetlb_instantiation_mutex held and pte_page locked so we 2514 * cannot race with other handlers or page migration. 2515 * Keep the pte_same checks anyway to make transition from the mutex easier. 2516 */ 2517 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2518 unsigned long address, pte_t *ptep, pte_t pte, 2519 struct page *pagecache_page) 2520 { 2521 struct hstate *h = hstate_vma(vma); 2522 struct page *old_page, *new_page; 2523 int avoidcopy; 2524 int outside_reserve = 0; 2525 unsigned long mmun_start; /* For mmu_notifiers */ 2526 unsigned long mmun_end; /* For mmu_notifiers */ 2527 2528 old_page = pte_page(pte); 2529 2530 retry_avoidcopy: 2531 /* If no-one else is actually using this page, avoid the copy 2532 * and just make the page writable */ 2533 avoidcopy = (page_mapcount(old_page) == 1); 2534 if (avoidcopy) { 2535 if (PageAnon(old_page)) 2536 page_move_anon_rmap(old_page, vma, address); 2537 set_huge_ptep_writable(vma, address, ptep); 2538 return 0; 2539 } 2540 2541 /* 2542 * If the process that created a MAP_PRIVATE mapping is about to 2543 * perform a COW due to a shared page count, attempt to satisfy 2544 * the allocation without using the existing reserves. The pagecache 2545 * page is used to determine if the reserve at this address was 2546 * consumed or not. If reserves were used, a partial faulted mapping 2547 * at the time of fork() could consume its reserves on COW instead 2548 * of the full address range. 2549 */ 2550 if (!(vma->vm_flags & VM_MAYSHARE) && 2551 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2552 old_page != pagecache_page) 2553 outside_reserve = 1; 2554 2555 page_cache_get(old_page); 2556 2557 /* Drop page_table_lock as buddy allocator may be called */ 2558 spin_unlock(&mm->page_table_lock); 2559 new_page = alloc_huge_page(vma, address, outside_reserve); 2560 2561 if (IS_ERR(new_page)) { 2562 long err = PTR_ERR(new_page); 2563 page_cache_release(old_page); 2564 2565 /* 2566 * If a process owning a MAP_PRIVATE mapping fails to COW, 2567 * it is due to references held by a child and an insufficient 2568 * huge page pool. To guarantee the original mappers 2569 * reliability, unmap the page from child processes. The child 2570 * may get SIGKILLed if it later faults. 2571 */ 2572 if (outside_reserve) { 2573 BUG_ON(huge_pte_none(pte)); 2574 if (unmap_ref_private(mm, vma, old_page, address)) { 2575 BUG_ON(huge_pte_none(pte)); 2576 spin_lock(&mm->page_table_lock); 2577 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2578 if (likely(pte_same(huge_ptep_get(ptep), pte))) 2579 goto retry_avoidcopy; 2580 /* 2581 * race occurs while re-acquiring page_table_lock, and 2582 * our job is done. 2583 */ 2584 return 0; 2585 } 2586 WARN_ON_ONCE(1); 2587 } 2588 2589 /* Caller expects lock to be held */ 2590 spin_lock(&mm->page_table_lock); 2591 if (err == -ENOMEM) 2592 return VM_FAULT_OOM; 2593 else 2594 return VM_FAULT_SIGBUS; 2595 } 2596 2597 /* 2598 * When the original hugepage is shared one, it does not have 2599 * anon_vma prepared. 2600 */ 2601 if (unlikely(anon_vma_prepare(vma))) { 2602 page_cache_release(new_page); 2603 page_cache_release(old_page); 2604 /* Caller expects lock to be held */ 2605 spin_lock(&mm->page_table_lock); 2606 return VM_FAULT_OOM; 2607 } 2608 2609 copy_user_huge_page(new_page, old_page, address, vma, 2610 pages_per_huge_page(h)); 2611 __SetPageUptodate(new_page); 2612 2613 mmun_start = address & huge_page_mask(h); 2614 mmun_end = mmun_start + huge_page_size(h); 2615 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2616 /* 2617 * Retake the page_table_lock to check for racing updates 2618 * before the page tables are altered 2619 */ 2620 spin_lock(&mm->page_table_lock); 2621 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2622 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2623 /* Break COW */ 2624 huge_ptep_clear_flush(vma, address, ptep); 2625 set_huge_pte_at(mm, address, ptep, 2626 make_huge_pte(vma, new_page, 1)); 2627 page_remove_rmap(old_page); 2628 hugepage_add_new_anon_rmap(new_page, vma, address); 2629 /* Make the old page be freed below */ 2630 new_page = old_page; 2631 } 2632 spin_unlock(&mm->page_table_lock); 2633 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2634 /* Caller expects lock to be held */ 2635 spin_lock(&mm->page_table_lock); 2636 page_cache_release(new_page); 2637 page_cache_release(old_page); 2638 return 0; 2639 } 2640 2641 /* Return the pagecache page at a given address within a VMA */ 2642 static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2643 struct vm_area_struct *vma, unsigned long address) 2644 { 2645 struct address_space *mapping; 2646 pgoff_t idx; 2647 2648 mapping = vma->vm_file->f_mapping; 2649 idx = vma_hugecache_offset(h, vma, address); 2650 2651 return find_lock_page(mapping, idx); 2652 } 2653 2654 /* 2655 * Return whether there is a pagecache page to back given address within VMA. 2656 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2657 */ 2658 static bool hugetlbfs_pagecache_present(struct hstate *h, 2659 struct vm_area_struct *vma, unsigned long address) 2660 { 2661 struct address_space *mapping; 2662 pgoff_t idx; 2663 struct page *page; 2664 2665 mapping = vma->vm_file->f_mapping; 2666 idx = vma_hugecache_offset(h, vma, address); 2667 2668 page = find_get_page(mapping, idx); 2669 if (page) 2670 put_page(page); 2671 return page != NULL; 2672 } 2673 2674 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2675 unsigned long address, pte_t *ptep, unsigned int flags) 2676 { 2677 struct hstate *h = hstate_vma(vma); 2678 int ret = VM_FAULT_SIGBUS; 2679 int anon_rmap = 0; 2680 pgoff_t idx; 2681 unsigned long size; 2682 struct page *page; 2683 struct address_space *mapping; 2684 pte_t new_pte; 2685 2686 /* 2687 * Currently, we are forced to kill the process in the event the 2688 * original mapper has unmapped pages from the child due to a failed 2689 * COW. Warn that such a situation has occurred as it may not be obvious 2690 */ 2691 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2692 pr_warning("PID %d killed due to inadequate hugepage pool\n", 2693 current->pid); 2694 return ret; 2695 } 2696 2697 mapping = vma->vm_file->f_mapping; 2698 idx = vma_hugecache_offset(h, vma, address); 2699 2700 /* 2701 * Use page lock to guard against racing truncation 2702 * before we get page_table_lock. 2703 */ 2704 retry: 2705 page = find_lock_page(mapping, idx); 2706 if (!page) { 2707 size = i_size_read(mapping->host) >> huge_page_shift(h); 2708 if (idx >= size) 2709 goto out; 2710 page = alloc_huge_page(vma, address, 0); 2711 if (IS_ERR(page)) { 2712 ret = PTR_ERR(page); 2713 if (ret == -ENOMEM) 2714 ret = VM_FAULT_OOM; 2715 else 2716 ret = VM_FAULT_SIGBUS; 2717 goto out; 2718 } 2719 clear_huge_page(page, address, pages_per_huge_page(h)); 2720 __SetPageUptodate(page); 2721 2722 if (vma->vm_flags & VM_MAYSHARE) { 2723 int err; 2724 struct inode *inode = mapping->host; 2725 2726 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2727 if (err) { 2728 put_page(page); 2729 if (err == -EEXIST) 2730 goto retry; 2731 goto out; 2732 } 2733 2734 spin_lock(&inode->i_lock); 2735 inode->i_blocks += blocks_per_huge_page(h); 2736 spin_unlock(&inode->i_lock); 2737 } else { 2738 lock_page(page); 2739 if (unlikely(anon_vma_prepare(vma))) { 2740 ret = VM_FAULT_OOM; 2741 goto backout_unlocked; 2742 } 2743 anon_rmap = 1; 2744 } 2745 } else { 2746 /* 2747 * If memory error occurs between mmap() and fault, some process 2748 * don't have hwpoisoned swap entry for errored virtual address. 2749 * So we need to block hugepage fault by PG_hwpoison bit check. 2750 */ 2751 if (unlikely(PageHWPoison(page))) { 2752 ret = VM_FAULT_HWPOISON | 2753 VM_FAULT_SET_HINDEX(hstate_index(h)); 2754 goto backout_unlocked; 2755 } 2756 } 2757 2758 /* 2759 * If we are going to COW a private mapping later, we examine the 2760 * pending reservations for this page now. This will ensure that 2761 * any allocations necessary to record that reservation occur outside 2762 * the spinlock. 2763 */ 2764 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2765 if (vma_needs_reservation(h, vma, address) < 0) { 2766 ret = VM_FAULT_OOM; 2767 goto backout_unlocked; 2768 } 2769 2770 spin_lock(&mm->page_table_lock); 2771 size = i_size_read(mapping->host) >> huge_page_shift(h); 2772 if (idx >= size) 2773 goto backout; 2774 2775 ret = 0; 2776 if (!huge_pte_none(huge_ptep_get(ptep))) 2777 goto backout; 2778 2779 if (anon_rmap) 2780 hugepage_add_new_anon_rmap(page, vma, address); 2781 else 2782 page_dup_rmap(page); 2783 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2784 && (vma->vm_flags & VM_SHARED))); 2785 set_huge_pte_at(mm, address, ptep, new_pte); 2786 2787 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2788 /* Optimization, do the COW without a second fault */ 2789 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2790 } 2791 2792 spin_unlock(&mm->page_table_lock); 2793 unlock_page(page); 2794 out: 2795 return ret; 2796 2797 backout: 2798 spin_unlock(&mm->page_table_lock); 2799 backout_unlocked: 2800 unlock_page(page); 2801 put_page(page); 2802 goto out; 2803 } 2804 2805 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2806 unsigned long address, unsigned int flags) 2807 { 2808 pte_t *ptep; 2809 pte_t entry; 2810 int ret; 2811 struct page *page = NULL; 2812 struct page *pagecache_page = NULL; 2813 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2814 struct hstate *h = hstate_vma(vma); 2815 2816 address &= huge_page_mask(h); 2817 2818 ptep = huge_pte_offset(mm, address); 2819 if (ptep) { 2820 entry = huge_ptep_get(ptep); 2821 if (unlikely(is_hugetlb_entry_migration(entry))) { 2822 migration_entry_wait(mm, (pmd_t *)ptep, address); 2823 return 0; 2824 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) 2825 return VM_FAULT_HWPOISON_LARGE | 2826 VM_FAULT_SET_HINDEX(hstate_index(h)); 2827 } 2828 2829 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2830 if (!ptep) 2831 return VM_FAULT_OOM; 2832 2833 /* 2834 * Serialize hugepage allocation and instantiation, so that we don't 2835 * get spurious allocation failures if two CPUs race to instantiate 2836 * the same page in the page cache. 2837 */ 2838 mutex_lock(&hugetlb_instantiation_mutex); 2839 entry = huge_ptep_get(ptep); 2840 if (huge_pte_none(entry)) { 2841 ret = hugetlb_no_page(mm, vma, address, ptep, flags); 2842 goto out_mutex; 2843 } 2844 2845 ret = 0; 2846 2847 /* 2848 * If we are going to COW the mapping later, we examine the pending 2849 * reservations for this page now. This will ensure that any 2850 * allocations necessary to record that reservation occur outside the 2851 * spinlock. For private mappings, we also lookup the pagecache 2852 * page now as it is used to determine if a reservation has been 2853 * consumed. 2854 */ 2855 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) { 2856 if (vma_needs_reservation(h, vma, address) < 0) { 2857 ret = VM_FAULT_OOM; 2858 goto out_mutex; 2859 } 2860 2861 if (!(vma->vm_flags & VM_MAYSHARE)) 2862 pagecache_page = hugetlbfs_pagecache_page(h, 2863 vma, address); 2864 } 2865 2866 /* 2867 * hugetlb_cow() requires page locks of pte_page(entry) and 2868 * pagecache_page, so here we need take the former one 2869 * when page != pagecache_page or !pagecache_page. 2870 * Note that locking order is always pagecache_page -> page, 2871 * so no worry about deadlock. 2872 */ 2873 page = pte_page(entry); 2874 get_page(page); 2875 if (page != pagecache_page) 2876 lock_page(page); 2877 2878 spin_lock(&mm->page_table_lock); 2879 /* Check for a racing update before calling hugetlb_cow */ 2880 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2881 goto out_page_table_lock; 2882 2883 2884 if (flags & FAULT_FLAG_WRITE) { 2885 if (!pte_write(entry)) { 2886 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2887 pagecache_page); 2888 goto out_page_table_lock; 2889 } 2890 entry = pte_mkdirty(entry); 2891 } 2892 entry = pte_mkyoung(entry); 2893 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 2894 flags & FAULT_FLAG_WRITE)) 2895 update_mmu_cache(vma, address, ptep); 2896 2897 out_page_table_lock: 2898 spin_unlock(&mm->page_table_lock); 2899 2900 if (pagecache_page) { 2901 unlock_page(pagecache_page); 2902 put_page(pagecache_page); 2903 } 2904 if (page != pagecache_page) 2905 unlock_page(page); 2906 put_page(page); 2907 2908 out_mutex: 2909 mutex_unlock(&hugetlb_instantiation_mutex); 2910 2911 return ret; 2912 } 2913 2914 /* Can be overriden by architectures */ 2915 __attribute__((weak)) struct page * 2916 follow_huge_pud(struct mm_struct *mm, unsigned long address, 2917 pud_t *pud, int write) 2918 { 2919 BUG(); 2920 return NULL; 2921 } 2922 2923 long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2924 struct page **pages, struct vm_area_struct **vmas, 2925 unsigned long *position, unsigned long *nr_pages, 2926 long i, unsigned int flags) 2927 { 2928 unsigned long pfn_offset; 2929 unsigned long vaddr = *position; 2930 unsigned long remainder = *nr_pages; 2931 struct hstate *h = hstate_vma(vma); 2932 2933 spin_lock(&mm->page_table_lock); 2934 while (vaddr < vma->vm_end && remainder) { 2935 pte_t *pte; 2936 int absent; 2937 struct page *page; 2938 2939 /* 2940 * Some archs (sparc64, sh*) have multiple pte_ts to 2941 * each hugepage. We have to make sure we get the 2942 * first, for the page indexing below to work. 2943 */ 2944 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2945 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 2946 2947 /* 2948 * When coredumping, it suits get_dump_page if we just return 2949 * an error where there's an empty slot with no huge pagecache 2950 * to back it. This way, we avoid allocating a hugepage, and 2951 * the sparse dumpfile avoids allocating disk blocks, but its 2952 * huge holes still show up with zeroes where they need to be. 2953 */ 2954 if (absent && (flags & FOLL_DUMP) && 2955 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 2956 remainder = 0; 2957 break; 2958 } 2959 2960 if (absent || 2961 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) { 2962 int ret; 2963 2964 spin_unlock(&mm->page_table_lock); 2965 ret = hugetlb_fault(mm, vma, vaddr, 2966 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 2967 spin_lock(&mm->page_table_lock); 2968 if (!(ret & VM_FAULT_ERROR)) 2969 continue; 2970 2971 remainder = 0; 2972 break; 2973 } 2974 2975 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2976 page = pte_page(huge_ptep_get(pte)); 2977 same_page: 2978 if (pages) { 2979 pages[i] = mem_map_offset(page, pfn_offset); 2980 get_page(pages[i]); 2981 } 2982 2983 if (vmas) 2984 vmas[i] = vma; 2985 2986 vaddr += PAGE_SIZE; 2987 ++pfn_offset; 2988 --remainder; 2989 ++i; 2990 if (vaddr < vma->vm_end && remainder && 2991 pfn_offset < pages_per_huge_page(h)) { 2992 /* 2993 * We use pfn_offset to avoid touching the pageframes 2994 * of this compound page. 2995 */ 2996 goto same_page; 2997 } 2998 } 2999 spin_unlock(&mm->page_table_lock); 3000 *nr_pages = remainder; 3001 *position = vaddr; 3002 3003 return i ? i : -EFAULT; 3004 } 3005 3006 unsigned long hugetlb_change_protection(struct vm_area_struct *vma, 3007 unsigned long address, unsigned long end, pgprot_t newprot) 3008 { 3009 struct mm_struct *mm = vma->vm_mm; 3010 unsigned long start = address; 3011 pte_t *ptep; 3012 pte_t pte; 3013 struct hstate *h = hstate_vma(vma); 3014 unsigned long pages = 0; 3015 3016 BUG_ON(address >= end); 3017 flush_cache_range(vma, address, end); 3018 3019 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 3020 spin_lock(&mm->page_table_lock); 3021 for (; address < end; address += huge_page_size(h)) { 3022 ptep = huge_pte_offset(mm, address); 3023 if (!ptep) 3024 continue; 3025 if (huge_pmd_unshare(mm, &address, ptep)) { 3026 pages++; 3027 continue; 3028 } 3029 if (!huge_pte_none(huge_ptep_get(ptep))) { 3030 pte = huge_ptep_get_and_clear(mm, address, ptep); 3031 pte = pte_mkhuge(pte_modify(pte, newprot)); 3032 pte = arch_make_huge_pte(pte, vma, NULL, 0); 3033 set_huge_pte_at(mm, address, ptep, pte); 3034 pages++; 3035 } 3036 } 3037 spin_unlock(&mm->page_table_lock); 3038 /* 3039 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare 3040 * may have cleared our pud entry and done put_page on the page table: 3041 * once we release i_mmap_mutex, another task can do the final put_page 3042 * and that page table be reused and filled with junk. 3043 */ 3044 flush_tlb_range(vma, start, end); 3045 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 3046 3047 return pages << h->order; 3048 } 3049 3050 int hugetlb_reserve_pages(struct inode *inode, 3051 long from, long to, 3052 struct vm_area_struct *vma, 3053 vm_flags_t vm_flags) 3054 { 3055 long ret, chg; 3056 struct hstate *h = hstate_inode(inode); 3057 struct hugepage_subpool *spool = subpool_inode(inode); 3058 3059 /* 3060 * Only apply hugepage reservation if asked. At fault time, an 3061 * attempt will be made for VM_NORESERVE to allocate a page 3062 * without using reserves 3063 */ 3064 if (vm_flags & VM_NORESERVE) 3065 return 0; 3066 3067 /* 3068 * Shared mappings base their reservation on the number of pages that 3069 * are already allocated on behalf of the file. Private mappings need 3070 * to reserve the full area even if read-only as mprotect() may be 3071 * called to make the mapping read-write. Assume !vma is a shm mapping 3072 */ 3073 if (!vma || vma->vm_flags & VM_MAYSHARE) 3074 chg = region_chg(&inode->i_mapping->private_list, from, to); 3075 else { 3076 struct resv_map *resv_map = resv_map_alloc(); 3077 if (!resv_map) 3078 return -ENOMEM; 3079 3080 chg = to - from; 3081 3082 set_vma_resv_map(vma, resv_map); 3083 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 3084 } 3085 3086 if (chg < 0) { 3087 ret = chg; 3088 goto out_err; 3089 } 3090 3091 /* There must be enough pages in the subpool for the mapping */ 3092 if (hugepage_subpool_get_pages(spool, chg)) { 3093 ret = -ENOSPC; 3094 goto out_err; 3095 } 3096 3097 /* 3098 * Check enough hugepages are available for the reservation. 3099 * Hand the pages back to the subpool if there are not 3100 */ 3101 ret = hugetlb_acct_memory(h, chg); 3102 if (ret < 0) { 3103 hugepage_subpool_put_pages(spool, chg); 3104 goto out_err; 3105 } 3106 3107 /* 3108 * Account for the reservations made. Shared mappings record regions 3109 * that have reservations as they are shared by multiple VMAs. 3110 * When the last VMA disappears, the region map says how much 3111 * the reservation was and the page cache tells how much of 3112 * the reservation was consumed. Private mappings are per-VMA and 3113 * only the consumed reservations are tracked. When the VMA 3114 * disappears, the original reservation is the VMA size and the 3115 * consumed reservations are stored in the map. Hence, nothing 3116 * else has to be done for private mappings here 3117 */ 3118 if (!vma || vma->vm_flags & VM_MAYSHARE) 3119 region_add(&inode->i_mapping->private_list, from, to); 3120 return 0; 3121 out_err: 3122 if (vma) 3123 resv_map_put(vma); 3124 return ret; 3125 } 3126 3127 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 3128 { 3129 struct hstate *h = hstate_inode(inode); 3130 long chg = region_truncate(&inode->i_mapping->private_list, offset); 3131 struct hugepage_subpool *spool = subpool_inode(inode); 3132 3133 spin_lock(&inode->i_lock); 3134 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 3135 spin_unlock(&inode->i_lock); 3136 3137 hugepage_subpool_put_pages(spool, (chg - freed)); 3138 hugetlb_acct_memory(h, -(chg - freed)); 3139 } 3140 3141 #ifdef CONFIG_MEMORY_FAILURE 3142 3143 /* Should be called in hugetlb_lock */ 3144 static int is_hugepage_on_freelist(struct page *hpage) 3145 { 3146 struct page *page; 3147 struct page *tmp; 3148 struct hstate *h = page_hstate(hpage); 3149 int nid = page_to_nid(hpage); 3150 3151 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) 3152 if (page == hpage) 3153 return 1; 3154 return 0; 3155 } 3156 3157 /* 3158 * This function is called from memory failure code. 3159 * Assume the caller holds page lock of the head page. 3160 */ 3161 int dequeue_hwpoisoned_huge_page(struct page *hpage) 3162 { 3163 struct hstate *h = page_hstate(hpage); 3164 int nid = page_to_nid(hpage); 3165 int ret = -EBUSY; 3166 3167 spin_lock(&hugetlb_lock); 3168 if (is_hugepage_on_freelist(hpage)) { 3169 /* 3170 * Hwpoisoned hugepage isn't linked to activelist or freelist, 3171 * but dangling hpage->lru can trigger list-debug warnings 3172 * (this happens when we call unpoison_memory() on it), 3173 * so let it point to itself with list_del_init(). 3174 */ 3175 list_del_init(&hpage->lru); 3176 set_page_refcounted(hpage); 3177 h->free_huge_pages--; 3178 h->free_huge_pages_node[nid]--; 3179 ret = 0; 3180 } 3181 spin_unlock(&hugetlb_lock); 3182 return ret; 3183 } 3184 #endif 3185