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