1 /* 2 * Generic hugetlb support. 3 * (C) William Irwin, April 2004 4 */ 5 #include <linux/gfp.h> 6 #include <linux/list.h> 7 #include <linux/init.h> 8 #include <linux/module.h> 9 #include <linux/mm.h> 10 #include <linux/seq_file.h> 11 #include <linux/sysctl.h> 12 #include <linux/highmem.h> 13 #include <linux/mmu_notifier.h> 14 #include <linux/nodemask.h> 15 #include <linux/pagemap.h> 16 #include <linux/mempolicy.h> 17 #include <linux/cpuset.h> 18 #include <linux/mutex.h> 19 #include <linux/bootmem.h> 20 #include <linux/sysfs.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 = huge_zonelist(vma, address, 469 htlb_alloc_mask, &mpol, &nodemask); 470 struct zone *zone; 471 struct zoneref *z; 472 473 /* 474 * A child process with MAP_PRIVATE mappings created by their parent 475 * have no page reserves. This check ensures that reservations are 476 * not "stolen". The child may still get SIGKILLed 477 */ 478 if (!vma_has_reserves(vma) && 479 h->free_huge_pages - h->resv_huge_pages == 0) 480 return NULL; 481 482 /* If reserves cannot be used, ensure enough pages are in the pool */ 483 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 484 return NULL; 485 486 for_each_zone_zonelist_nodemask(zone, z, zonelist, 487 MAX_NR_ZONES - 1, nodemask) { 488 nid = zone_to_nid(zone); 489 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && 490 !list_empty(&h->hugepage_freelists[nid])) { 491 page = list_entry(h->hugepage_freelists[nid].next, 492 struct page, lru); 493 list_del(&page->lru); 494 h->free_huge_pages--; 495 h->free_huge_pages_node[nid]--; 496 497 if (!avoid_reserve) 498 decrement_hugepage_resv_vma(h, vma); 499 500 break; 501 } 502 } 503 mpol_cond_put(mpol); 504 return page; 505 } 506 507 static void update_and_free_page(struct hstate *h, struct page *page) 508 { 509 int i; 510 511 VM_BUG_ON(h->order >= MAX_ORDER); 512 513 h->nr_huge_pages--; 514 h->nr_huge_pages_node[page_to_nid(page)]--; 515 for (i = 0; i < pages_per_huge_page(h); i++) { 516 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 517 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 518 1 << PG_private | 1<< PG_writeback); 519 } 520 set_compound_page_dtor(page, NULL); 521 set_page_refcounted(page); 522 arch_release_hugepage(page); 523 __free_pages(page, huge_page_order(h)); 524 } 525 526 struct hstate *size_to_hstate(unsigned long size) 527 { 528 struct hstate *h; 529 530 for_each_hstate(h) { 531 if (huge_page_size(h) == size) 532 return h; 533 } 534 return NULL; 535 } 536 537 static void free_huge_page(struct page *page) 538 { 539 /* 540 * Can't pass hstate in here because it is called from the 541 * compound page destructor. 542 */ 543 struct hstate *h = page_hstate(page); 544 int nid = page_to_nid(page); 545 struct address_space *mapping; 546 547 mapping = (struct address_space *) page_private(page); 548 set_page_private(page, 0); 549 BUG_ON(page_count(page)); 550 INIT_LIST_HEAD(&page->lru); 551 552 spin_lock(&hugetlb_lock); 553 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 554 update_and_free_page(h, page); 555 h->surplus_huge_pages--; 556 h->surplus_huge_pages_node[nid]--; 557 } else { 558 enqueue_huge_page(h, page); 559 } 560 spin_unlock(&hugetlb_lock); 561 if (mapping) 562 hugetlb_put_quota(mapping, 1); 563 } 564 565 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 566 { 567 set_compound_page_dtor(page, free_huge_page); 568 spin_lock(&hugetlb_lock); 569 h->nr_huge_pages++; 570 h->nr_huge_pages_node[nid]++; 571 spin_unlock(&hugetlb_lock); 572 put_page(page); /* free it into the hugepage allocator */ 573 } 574 575 static void prep_compound_gigantic_page(struct page *page, unsigned long order) 576 { 577 int i; 578 int nr_pages = 1 << order; 579 struct page *p = page + 1; 580 581 /* we rely on prep_new_huge_page to set the destructor */ 582 set_compound_order(page, order); 583 __SetPageHead(page); 584 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 585 __SetPageTail(p); 586 p->first_page = page; 587 } 588 } 589 590 int PageHuge(struct page *page) 591 { 592 compound_page_dtor *dtor; 593 594 if (!PageCompound(page)) 595 return 0; 596 597 page = compound_head(page); 598 dtor = get_compound_page_dtor(page); 599 600 return dtor == free_huge_page; 601 } 602 603 static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 604 { 605 struct page *page; 606 607 if (h->order >= MAX_ORDER) 608 return NULL; 609 610 page = alloc_pages_exact_node(nid, 611 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 612 __GFP_REPEAT|__GFP_NOWARN, 613 huge_page_order(h)); 614 if (page) { 615 if (arch_prepare_hugepage(page)) { 616 __free_pages(page, huge_page_order(h)); 617 return NULL; 618 } 619 prep_new_huge_page(h, page, nid); 620 } 621 622 return page; 623 } 624 625 /* 626 * common helper functions for hstate_next_node_to_{alloc|free}. 627 * We may have allocated or freed a huge page based on a different 628 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 629 * be outside of *nodes_allowed. Ensure that we use an allowed 630 * node for alloc or free. 631 */ 632 static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 633 { 634 nid = next_node(nid, *nodes_allowed); 635 if (nid == MAX_NUMNODES) 636 nid = first_node(*nodes_allowed); 637 VM_BUG_ON(nid >= MAX_NUMNODES); 638 639 return nid; 640 } 641 642 static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 643 { 644 if (!node_isset(nid, *nodes_allowed)) 645 nid = next_node_allowed(nid, nodes_allowed); 646 return nid; 647 } 648 649 /* 650 * returns the previously saved node ["this node"] from which to 651 * allocate a persistent huge page for the pool and advance the 652 * next node from which to allocate, handling wrap at end of node 653 * mask. 654 */ 655 static int hstate_next_node_to_alloc(struct hstate *h, 656 nodemask_t *nodes_allowed) 657 { 658 int nid; 659 660 VM_BUG_ON(!nodes_allowed); 661 662 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 663 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 664 665 return nid; 666 } 667 668 static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 669 { 670 struct page *page; 671 int start_nid; 672 int next_nid; 673 int ret = 0; 674 675 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 676 next_nid = start_nid; 677 678 do { 679 page = alloc_fresh_huge_page_node(h, next_nid); 680 if (page) { 681 ret = 1; 682 break; 683 } 684 next_nid = hstate_next_node_to_alloc(h, nodes_allowed); 685 } while (next_nid != start_nid); 686 687 if (ret) 688 count_vm_event(HTLB_BUDDY_PGALLOC); 689 else 690 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 691 692 return ret; 693 } 694 695 /* 696 * helper for free_pool_huge_page() - return the previously saved 697 * node ["this node"] from which to free a huge page. Advance the 698 * next node id whether or not we find a free huge page to free so 699 * that the next attempt to free addresses the next node. 700 */ 701 static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 702 { 703 int nid; 704 705 VM_BUG_ON(!nodes_allowed); 706 707 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 708 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 709 710 return nid; 711 } 712 713 /* 714 * Free huge page from pool from next node to free. 715 * Attempt to keep persistent huge pages more or less 716 * balanced over allowed nodes. 717 * Called with hugetlb_lock locked. 718 */ 719 static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 720 bool acct_surplus) 721 { 722 int start_nid; 723 int next_nid; 724 int ret = 0; 725 726 start_nid = hstate_next_node_to_free(h, nodes_allowed); 727 next_nid = start_nid; 728 729 do { 730 /* 731 * If we're returning unused surplus pages, only examine 732 * nodes with surplus pages. 733 */ 734 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && 735 !list_empty(&h->hugepage_freelists[next_nid])) { 736 struct page *page = 737 list_entry(h->hugepage_freelists[next_nid].next, 738 struct page, lru); 739 list_del(&page->lru); 740 h->free_huge_pages--; 741 h->free_huge_pages_node[next_nid]--; 742 if (acct_surplus) { 743 h->surplus_huge_pages--; 744 h->surplus_huge_pages_node[next_nid]--; 745 } 746 update_and_free_page(h, page); 747 ret = 1; 748 break; 749 } 750 next_nid = hstate_next_node_to_free(h, nodes_allowed); 751 } while (next_nid != start_nid); 752 753 return ret; 754 } 755 756 static struct page *alloc_buddy_huge_page(struct hstate *h, 757 struct vm_area_struct *vma, unsigned long address) 758 { 759 struct page *page; 760 unsigned int nid; 761 762 if (h->order >= MAX_ORDER) 763 return NULL; 764 765 /* 766 * Assume we will successfully allocate the surplus page to 767 * prevent racing processes from causing the surplus to exceed 768 * overcommit 769 * 770 * This however introduces a different race, where a process B 771 * tries to grow the static hugepage pool while alloc_pages() is 772 * called by process A. B will only examine the per-node 773 * counters in determining if surplus huge pages can be 774 * converted to normal huge pages in adjust_pool_surplus(). A 775 * won't be able to increment the per-node counter, until the 776 * lock is dropped by B, but B doesn't drop hugetlb_lock until 777 * no more huge pages can be converted from surplus to normal 778 * state (and doesn't try to convert again). Thus, we have a 779 * case where a surplus huge page exists, the pool is grown, and 780 * the surplus huge page still exists after, even though it 781 * should just have been converted to a normal huge page. This 782 * does not leak memory, though, as the hugepage will be freed 783 * once it is out of use. It also does not allow the counters to 784 * go out of whack in adjust_pool_surplus() as we don't modify 785 * the node values until we've gotten the hugepage and only the 786 * per-node value is checked there. 787 */ 788 spin_lock(&hugetlb_lock); 789 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 790 spin_unlock(&hugetlb_lock); 791 return NULL; 792 } else { 793 h->nr_huge_pages++; 794 h->surplus_huge_pages++; 795 } 796 spin_unlock(&hugetlb_lock); 797 798 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 799 __GFP_REPEAT|__GFP_NOWARN, 800 huge_page_order(h)); 801 802 if (page && arch_prepare_hugepage(page)) { 803 __free_pages(page, huge_page_order(h)); 804 return NULL; 805 } 806 807 spin_lock(&hugetlb_lock); 808 if (page) { 809 /* 810 * This page is now managed by the hugetlb allocator and has 811 * no users -- drop the buddy allocator's reference. 812 */ 813 put_page_testzero(page); 814 VM_BUG_ON(page_count(page)); 815 nid = page_to_nid(page); 816 set_compound_page_dtor(page, free_huge_page); 817 /* 818 * We incremented the global counters already 819 */ 820 h->nr_huge_pages_node[nid]++; 821 h->surplus_huge_pages_node[nid]++; 822 __count_vm_event(HTLB_BUDDY_PGALLOC); 823 } else { 824 h->nr_huge_pages--; 825 h->surplus_huge_pages--; 826 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 827 } 828 spin_unlock(&hugetlb_lock); 829 830 return page; 831 } 832 833 /* 834 * Increase the hugetlb pool such that it can accomodate a reservation 835 * of size 'delta'. 836 */ 837 static int gather_surplus_pages(struct hstate *h, int delta) 838 { 839 struct list_head surplus_list; 840 struct page *page, *tmp; 841 int ret, i; 842 int needed, allocated; 843 844 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 845 if (needed <= 0) { 846 h->resv_huge_pages += delta; 847 return 0; 848 } 849 850 allocated = 0; 851 INIT_LIST_HEAD(&surplus_list); 852 853 ret = -ENOMEM; 854 retry: 855 spin_unlock(&hugetlb_lock); 856 for (i = 0; i < needed; i++) { 857 page = alloc_buddy_huge_page(h, NULL, 0); 858 if (!page) { 859 /* 860 * We were not able to allocate enough pages to 861 * satisfy the entire reservation so we free what 862 * we've allocated so far. 863 */ 864 spin_lock(&hugetlb_lock); 865 needed = 0; 866 goto free; 867 } 868 869 list_add(&page->lru, &surplus_list); 870 } 871 allocated += needed; 872 873 /* 874 * After retaking hugetlb_lock, we need to recalculate 'needed' 875 * because either resv_huge_pages or free_huge_pages may have changed. 876 */ 877 spin_lock(&hugetlb_lock); 878 needed = (h->resv_huge_pages + delta) - 879 (h->free_huge_pages + allocated); 880 if (needed > 0) 881 goto retry; 882 883 /* 884 * The surplus_list now contains _at_least_ the number of extra pages 885 * needed to accomodate the reservation. Add the appropriate number 886 * of pages to the hugetlb pool and free the extras back to the buddy 887 * allocator. Commit the entire reservation here to prevent another 888 * process from stealing the pages as they are added to the pool but 889 * before they are reserved. 890 */ 891 needed += allocated; 892 h->resv_huge_pages += delta; 893 ret = 0; 894 free: 895 /* Free the needed pages to the hugetlb pool */ 896 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 897 if ((--needed) < 0) 898 break; 899 list_del(&page->lru); 900 enqueue_huge_page(h, page); 901 } 902 903 /* Free unnecessary surplus pages to the buddy allocator */ 904 if (!list_empty(&surplus_list)) { 905 spin_unlock(&hugetlb_lock); 906 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 907 list_del(&page->lru); 908 /* 909 * The page has a reference count of zero already, so 910 * call free_huge_page directly instead of using 911 * put_page. This must be done with hugetlb_lock 912 * unlocked which is safe because free_huge_page takes 913 * hugetlb_lock before deciding how to free the page. 914 */ 915 free_huge_page(page); 916 } 917 spin_lock(&hugetlb_lock); 918 } 919 920 return ret; 921 } 922 923 /* 924 * When releasing a hugetlb pool reservation, any surplus pages that were 925 * allocated to satisfy the reservation must be explicitly freed if they were 926 * never used. 927 * Called with hugetlb_lock held. 928 */ 929 static void return_unused_surplus_pages(struct hstate *h, 930 unsigned long unused_resv_pages) 931 { 932 unsigned long nr_pages; 933 934 /* Uncommit the reservation */ 935 h->resv_huge_pages -= unused_resv_pages; 936 937 /* Cannot return gigantic pages currently */ 938 if (h->order >= MAX_ORDER) 939 return; 940 941 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 942 943 /* 944 * We want to release as many surplus pages as possible, spread 945 * evenly across all nodes with memory. Iterate across these nodes 946 * until we can no longer free unreserved surplus pages. This occurs 947 * when the nodes with surplus pages have no free pages. 948 * free_pool_huge_page() will balance the the freed pages across the 949 * on-line nodes with memory and will handle the hstate accounting. 950 */ 951 while (nr_pages--) { 952 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1)) 953 break; 954 } 955 } 956 957 /* 958 * Determine if the huge page at addr within the vma has an associated 959 * reservation. Where it does not we will need to logically increase 960 * reservation and actually increase quota before an allocation can occur. 961 * Where any new reservation would be required the reservation change is 962 * prepared, but not committed. Once the page has been quota'd allocated 963 * an instantiated the change should be committed via vma_commit_reservation. 964 * No action is required on failure. 965 */ 966 static long vma_needs_reservation(struct hstate *h, 967 struct vm_area_struct *vma, unsigned long addr) 968 { 969 struct address_space *mapping = vma->vm_file->f_mapping; 970 struct inode *inode = mapping->host; 971 972 if (vma->vm_flags & VM_MAYSHARE) { 973 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 974 return region_chg(&inode->i_mapping->private_list, 975 idx, idx + 1); 976 977 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 978 return 1; 979 980 } else { 981 long err; 982 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 983 struct resv_map *reservations = vma_resv_map(vma); 984 985 err = region_chg(&reservations->regions, idx, idx + 1); 986 if (err < 0) 987 return err; 988 return 0; 989 } 990 } 991 static void vma_commit_reservation(struct hstate *h, 992 struct vm_area_struct *vma, unsigned long addr) 993 { 994 struct address_space *mapping = vma->vm_file->f_mapping; 995 struct inode *inode = mapping->host; 996 997 if (vma->vm_flags & VM_MAYSHARE) { 998 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 999 region_add(&inode->i_mapping->private_list, idx, idx + 1); 1000 1001 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1002 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1003 struct resv_map *reservations = vma_resv_map(vma); 1004 1005 /* Mark this page used in the map. */ 1006 region_add(&reservations->regions, idx, idx + 1); 1007 } 1008 } 1009 1010 static struct page *alloc_huge_page(struct vm_area_struct *vma, 1011 unsigned long addr, int avoid_reserve) 1012 { 1013 struct hstate *h = hstate_vma(vma); 1014 struct page *page; 1015 struct address_space *mapping = vma->vm_file->f_mapping; 1016 struct inode *inode = mapping->host; 1017 long chg; 1018 1019 /* 1020 * Processes that did not create the mapping will have no reserves and 1021 * will not have accounted against quota. Check that the quota can be 1022 * made before satisfying the allocation 1023 * MAP_NORESERVE mappings may also need pages and quota allocated 1024 * if no reserve mapping overlaps. 1025 */ 1026 chg = vma_needs_reservation(h, vma, addr); 1027 if (chg < 0) 1028 return ERR_PTR(chg); 1029 if (chg) 1030 if (hugetlb_get_quota(inode->i_mapping, chg)) 1031 return ERR_PTR(-ENOSPC); 1032 1033 spin_lock(&hugetlb_lock); 1034 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 1035 spin_unlock(&hugetlb_lock); 1036 1037 if (!page) { 1038 page = alloc_buddy_huge_page(h, vma, addr); 1039 if (!page) { 1040 hugetlb_put_quota(inode->i_mapping, chg); 1041 return ERR_PTR(-VM_FAULT_OOM); 1042 } 1043 } 1044 1045 set_page_refcounted(page); 1046 set_page_private(page, (unsigned long) mapping); 1047 1048 vma_commit_reservation(h, vma, addr); 1049 1050 return page; 1051 } 1052 1053 int __weak alloc_bootmem_huge_page(struct hstate *h) 1054 { 1055 struct huge_bootmem_page *m; 1056 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]); 1057 1058 while (nr_nodes) { 1059 void *addr; 1060 1061 addr = __alloc_bootmem_node_nopanic( 1062 NODE_DATA(hstate_next_node_to_alloc(h, 1063 &node_states[N_HIGH_MEMORY])), 1064 huge_page_size(h), huge_page_size(h), 0); 1065 1066 if (addr) { 1067 /* 1068 * Use the beginning of the huge page to store the 1069 * huge_bootmem_page struct (until gather_bootmem 1070 * puts them into the mem_map). 1071 */ 1072 m = addr; 1073 goto found; 1074 } 1075 nr_nodes--; 1076 } 1077 return 0; 1078 1079 found: 1080 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1081 /* Put them into a private list first because mem_map is not up yet */ 1082 list_add(&m->list, &huge_boot_pages); 1083 m->hstate = h; 1084 return 1; 1085 } 1086 1087 static void prep_compound_huge_page(struct page *page, int order) 1088 { 1089 if (unlikely(order > (MAX_ORDER - 1))) 1090 prep_compound_gigantic_page(page, order); 1091 else 1092 prep_compound_page(page, order); 1093 } 1094 1095 /* Put bootmem huge pages into the standard lists after mem_map is up */ 1096 static void __init gather_bootmem_prealloc(void) 1097 { 1098 struct huge_bootmem_page *m; 1099 1100 list_for_each_entry(m, &huge_boot_pages, list) { 1101 struct page *page = virt_to_page(m); 1102 struct hstate *h = m->hstate; 1103 __ClearPageReserved(page); 1104 WARN_ON(page_count(page) != 1); 1105 prep_compound_huge_page(page, h->order); 1106 prep_new_huge_page(h, page, page_to_nid(page)); 1107 } 1108 } 1109 1110 static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1111 { 1112 unsigned long i; 1113 1114 for (i = 0; i < h->max_huge_pages; ++i) { 1115 if (h->order >= MAX_ORDER) { 1116 if (!alloc_bootmem_huge_page(h)) 1117 break; 1118 } else if (!alloc_fresh_huge_page(h, 1119 &node_states[N_HIGH_MEMORY])) 1120 break; 1121 } 1122 h->max_huge_pages = i; 1123 } 1124 1125 static void __init hugetlb_init_hstates(void) 1126 { 1127 struct hstate *h; 1128 1129 for_each_hstate(h) { 1130 /* oversize hugepages were init'ed in early boot */ 1131 if (h->order < MAX_ORDER) 1132 hugetlb_hstate_alloc_pages(h); 1133 } 1134 } 1135 1136 static char * __init memfmt(char *buf, unsigned long n) 1137 { 1138 if (n >= (1UL << 30)) 1139 sprintf(buf, "%lu GB", n >> 30); 1140 else if (n >= (1UL << 20)) 1141 sprintf(buf, "%lu MB", n >> 20); 1142 else 1143 sprintf(buf, "%lu KB", n >> 10); 1144 return buf; 1145 } 1146 1147 static void __init report_hugepages(void) 1148 { 1149 struct hstate *h; 1150 1151 for_each_hstate(h) { 1152 char buf[32]; 1153 printk(KERN_INFO "HugeTLB registered %s page size, " 1154 "pre-allocated %ld pages\n", 1155 memfmt(buf, huge_page_size(h)), 1156 h->free_huge_pages); 1157 } 1158 } 1159 1160 #ifdef CONFIG_HIGHMEM 1161 static void try_to_free_low(struct hstate *h, unsigned long count, 1162 nodemask_t *nodes_allowed) 1163 { 1164 int i; 1165 1166 if (h->order >= MAX_ORDER) 1167 return; 1168 1169 for_each_node_mask(i, *nodes_allowed) { 1170 struct page *page, *next; 1171 struct list_head *freel = &h->hugepage_freelists[i]; 1172 list_for_each_entry_safe(page, next, freel, lru) { 1173 if (count >= h->nr_huge_pages) 1174 return; 1175 if (PageHighMem(page)) 1176 continue; 1177 list_del(&page->lru); 1178 update_and_free_page(h, page); 1179 h->free_huge_pages--; 1180 h->free_huge_pages_node[page_to_nid(page)]--; 1181 } 1182 } 1183 } 1184 #else 1185 static inline void try_to_free_low(struct hstate *h, unsigned long count, 1186 nodemask_t *nodes_allowed) 1187 { 1188 } 1189 #endif 1190 1191 /* 1192 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1193 * balanced by operating on them in a round-robin fashion. 1194 * Returns 1 if an adjustment was made. 1195 */ 1196 static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1197 int delta) 1198 { 1199 int start_nid, next_nid; 1200 int ret = 0; 1201 1202 VM_BUG_ON(delta != -1 && delta != 1); 1203 1204 if (delta < 0) 1205 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 1206 else 1207 start_nid = hstate_next_node_to_free(h, nodes_allowed); 1208 next_nid = start_nid; 1209 1210 do { 1211 int nid = next_nid; 1212 if (delta < 0) { 1213 /* 1214 * To shrink on this node, there must be a surplus page 1215 */ 1216 if (!h->surplus_huge_pages_node[nid]) { 1217 next_nid = hstate_next_node_to_alloc(h, 1218 nodes_allowed); 1219 continue; 1220 } 1221 } 1222 if (delta > 0) { 1223 /* 1224 * Surplus cannot exceed the total number of pages 1225 */ 1226 if (h->surplus_huge_pages_node[nid] >= 1227 h->nr_huge_pages_node[nid]) { 1228 next_nid = hstate_next_node_to_free(h, 1229 nodes_allowed); 1230 continue; 1231 } 1232 } 1233 1234 h->surplus_huge_pages += delta; 1235 h->surplus_huge_pages_node[nid] += delta; 1236 ret = 1; 1237 break; 1238 } while (next_nid != start_nid); 1239 1240 return ret; 1241 } 1242 1243 #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1244 static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1245 nodemask_t *nodes_allowed) 1246 { 1247 unsigned long min_count, ret; 1248 1249 if (h->order >= MAX_ORDER) 1250 return h->max_huge_pages; 1251 1252 /* 1253 * Increase the pool size 1254 * First take pages out of surplus state. Then make up the 1255 * remaining difference by allocating fresh huge pages. 1256 * 1257 * We might race with alloc_buddy_huge_page() here and be unable 1258 * to convert a surplus huge page to a normal huge page. That is 1259 * not critical, though, it just means the overall size of the 1260 * pool might be one hugepage larger than it needs to be, but 1261 * within all the constraints specified by the sysctls. 1262 */ 1263 spin_lock(&hugetlb_lock); 1264 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1265 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1266 break; 1267 } 1268 1269 while (count > persistent_huge_pages(h)) { 1270 /* 1271 * If this allocation races such that we no longer need the 1272 * page, free_huge_page will handle it by freeing the page 1273 * and reducing the surplus. 1274 */ 1275 spin_unlock(&hugetlb_lock); 1276 ret = alloc_fresh_huge_page(h, nodes_allowed); 1277 spin_lock(&hugetlb_lock); 1278 if (!ret) 1279 goto out; 1280 1281 /* Bail for signals. Probably ctrl-c from user */ 1282 if (signal_pending(current)) 1283 goto out; 1284 } 1285 1286 /* 1287 * Decrease the pool size 1288 * First return free pages to the buddy allocator (being careful 1289 * to keep enough around to satisfy reservations). Then place 1290 * pages into surplus state as needed so the pool will shrink 1291 * to the desired size as pages become free. 1292 * 1293 * By placing pages into the surplus state independent of the 1294 * overcommit value, we are allowing the surplus pool size to 1295 * exceed overcommit. There are few sane options here. Since 1296 * alloc_buddy_huge_page() is checking the global counter, 1297 * though, we'll note that we're not allowed to exceed surplus 1298 * and won't grow the pool anywhere else. Not until one of the 1299 * sysctls are changed, or the surplus pages go out of use. 1300 */ 1301 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1302 min_count = max(count, min_count); 1303 try_to_free_low(h, min_count, nodes_allowed); 1304 while (min_count < persistent_huge_pages(h)) { 1305 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1306 break; 1307 } 1308 while (count < persistent_huge_pages(h)) { 1309 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1310 break; 1311 } 1312 out: 1313 ret = persistent_huge_pages(h); 1314 spin_unlock(&hugetlb_lock); 1315 return ret; 1316 } 1317 1318 #define HSTATE_ATTR_RO(_name) \ 1319 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1320 1321 #define HSTATE_ATTR(_name) \ 1322 static struct kobj_attribute _name##_attr = \ 1323 __ATTR(_name, 0644, _name##_show, _name##_store) 1324 1325 static struct kobject *hugepages_kobj; 1326 static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1327 1328 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1329 1330 static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1331 { 1332 int i; 1333 1334 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1335 if (hstate_kobjs[i] == kobj) { 1336 if (nidp) 1337 *nidp = NUMA_NO_NODE; 1338 return &hstates[i]; 1339 } 1340 1341 return kobj_to_node_hstate(kobj, nidp); 1342 } 1343 1344 static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1345 struct kobj_attribute *attr, char *buf) 1346 { 1347 struct hstate *h; 1348 unsigned long nr_huge_pages; 1349 int nid; 1350 1351 h = kobj_to_hstate(kobj, &nid); 1352 if (nid == NUMA_NO_NODE) 1353 nr_huge_pages = h->nr_huge_pages; 1354 else 1355 nr_huge_pages = h->nr_huge_pages_node[nid]; 1356 1357 return sprintf(buf, "%lu\n", nr_huge_pages); 1358 } 1359 static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1360 struct kobject *kobj, struct kobj_attribute *attr, 1361 const char *buf, size_t len) 1362 { 1363 int err; 1364 int nid; 1365 unsigned long count; 1366 struct hstate *h; 1367 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1368 1369 err = strict_strtoul(buf, 10, &count); 1370 if (err) 1371 return 0; 1372 1373 h = kobj_to_hstate(kobj, &nid); 1374 if (nid == NUMA_NO_NODE) { 1375 /* 1376 * global hstate attribute 1377 */ 1378 if (!(obey_mempolicy && 1379 init_nodemask_of_mempolicy(nodes_allowed))) { 1380 NODEMASK_FREE(nodes_allowed); 1381 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1382 } 1383 } else if (nodes_allowed) { 1384 /* 1385 * per node hstate attribute: adjust count to global, 1386 * but restrict alloc/free to the specified node. 1387 */ 1388 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1389 init_nodemask_of_node(nodes_allowed, nid); 1390 } else 1391 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1392 1393 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1394 1395 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1396 NODEMASK_FREE(nodes_allowed); 1397 1398 return len; 1399 } 1400 1401 static ssize_t nr_hugepages_show(struct kobject *kobj, 1402 struct kobj_attribute *attr, char *buf) 1403 { 1404 return nr_hugepages_show_common(kobj, attr, buf); 1405 } 1406 1407 static ssize_t nr_hugepages_store(struct kobject *kobj, 1408 struct kobj_attribute *attr, const char *buf, size_t len) 1409 { 1410 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1411 } 1412 HSTATE_ATTR(nr_hugepages); 1413 1414 #ifdef CONFIG_NUMA 1415 1416 /* 1417 * hstate attribute for optionally mempolicy-based constraint on persistent 1418 * huge page alloc/free. 1419 */ 1420 static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1421 struct kobj_attribute *attr, char *buf) 1422 { 1423 return nr_hugepages_show_common(kobj, attr, buf); 1424 } 1425 1426 static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1427 struct kobj_attribute *attr, const char *buf, size_t len) 1428 { 1429 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1430 } 1431 HSTATE_ATTR(nr_hugepages_mempolicy); 1432 #endif 1433 1434 1435 static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1436 struct kobj_attribute *attr, char *buf) 1437 { 1438 struct hstate *h = kobj_to_hstate(kobj, NULL); 1439 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1440 } 1441 static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1442 struct kobj_attribute *attr, const char *buf, size_t count) 1443 { 1444 int err; 1445 unsigned long input; 1446 struct hstate *h = kobj_to_hstate(kobj, NULL); 1447 1448 err = strict_strtoul(buf, 10, &input); 1449 if (err) 1450 return 0; 1451 1452 spin_lock(&hugetlb_lock); 1453 h->nr_overcommit_huge_pages = input; 1454 spin_unlock(&hugetlb_lock); 1455 1456 return count; 1457 } 1458 HSTATE_ATTR(nr_overcommit_hugepages); 1459 1460 static ssize_t free_hugepages_show(struct kobject *kobj, 1461 struct kobj_attribute *attr, char *buf) 1462 { 1463 struct hstate *h; 1464 unsigned long free_huge_pages; 1465 int nid; 1466 1467 h = kobj_to_hstate(kobj, &nid); 1468 if (nid == NUMA_NO_NODE) 1469 free_huge_pages = h->free_huge_pages; 1470 else 1471 free_huge_pages = h->free_huge_pages_node[nid]; 1472 1473 return sprintf(buf, "%lu\n", free_huge_pages); 1474 } 1475 HSTATE_ATTR_RO(free_hugepages); 1476 1477 static ssize_t resv_hugepages_show(struct kobject *kobj, 1478 struct kobj_attribute *attr, char *buf) 1479 { 1480 struct hstate *h = kobj_to_hstate(kobj, NULL); 1481 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1482 } 1483 HSTATE_ATTR_RO(resv_hugepages); 1484 1485 static ssize_t surplus_hugepages_show(struct kobject *kobj, 1486 struct kobj_attribute *attr, char *buf) 1487 { 1488 struct hstate *h; 1489 unsigned long surplus_huge_pages; 1490 int nid; 1491 1492 h = kobj_to_hstate(kobj, &nid); 1493 if (nid == NUMA_NO_NODE) 1494 surplus_huge_pages = h->surplus_huge_pages; 1495 else 1496 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1497 1498 return sprintf(buf, "%lu\n", surplus_huge_pages); 1499 } 1500 HSTATE_ATTR_RO(surplus_hugepages); 1501 1502 static struct attribute *hstate_attrs[] = { 1503 &nr_hugepages_attr.attr, 1504 &nr_overcommit_hugepages_attr.attr, 1505 &free_hugepages_attr.attr, 1506 &resv_hugepages_attr.attr, 1507 &surplus_hugepages_attr.attr, 1508 #ifdef CONFIG_NUMA 1509 &nr_hugepages_mempolicy_attr.attr, 1510 #endif 1511 NULL, 1512 }; 1513 1514 static struct attribute_group hstate_attr_group = { 1515 .attrs = hstate_attrs, 1516 }; 1517 1518 static int __init hugetlb_sysfs_add_hstate(struct hstate *h, 1519 struct kobject *parent, 1520 struct kobject **hstate_kobjs, 1521 struct attribute_group *hstate_attr_group) 1522 { 1523 int retval; 1524 int hi = h - hstates; 1525 1526 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1527 if (!hstate_kobjs[hi]) 1528 return -ENOMEM; 1529 1530 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1531 if (retval) 1532 kobject_put(hstate_kobjs[hi]); 1533 1534 return retval; 1535 } 1536 1537 static void __init hugetlb_sysfs_init(void) 1538 { 1539 struct hstate *h; 1540 int err; 1541 1542 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1543 if (!hugepages_kobj) 1544 return; 1545 1546 for_each_hstate(h) { 1547 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1548 hstate_kobjs, &hstate_attr_group); 1549 if (err) 1550 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1551 h->name); 1552 } 1553 } 1554 1555 #ifdef CONFIG_NUMA 1556 1557 /* 1558 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1559 * with node sysdevs in node_devices[] using a parallel array. The array 1560 * index of a node sysdev or _hstate == node id. 1561 * This is here to avoid any static dependency of the node sysdev driver, in 1562 * the base kernel, on the hugetlb module. 1563 */ 1564 struct node_hstate { 1565 struct kobject *hugepages_kobj; 1566 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1567 }; 1568 struct node_hstate node_hstates[MAX_NUMNODES]; 1569 1570 /* 1571 * A subset of global hstate attributes for node sysdevs 1572 */ 1573 static struct attribute *per_node_hstate_attrs[] = { 1574 &nr_hugepages_attr.attr, 1575 &free_hugepages_attr.attr, 1576 &surplus_hugepages_attr.attr, 1577 NULL, 1578 }; 1579 1580 static struct attribute_group per_node_hstate_attr_group = { 1581 .attrs = per_node_hstate_attrs, 1582 }; 1583 1584 /* 1585 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj. 1586 * Returns node id via non-NULL nidp. 1587 */ 1588 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1589 { 1590 int nid; 1591 1592 for (nid = 0; nid < nr_node_ids; nid++) { 1593 struct node_hstate *nhs = &node_hstates[nid]; 1594 int i; 1595 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1596 if (nhs->hstate_kobjs[i] == kobj) { 1597 if (nidp) 1598 *nidp = nid; 1599 return &hstates[i]; 1600 } 1601 } 1602 1603 BUG(); 1604 return NULL; 1605 } 1606 1607 /* 1608 * Unregister hstate attributes from a single node sysdev. 1609 * No-op if no hstate attributes attached. 1610 */ 1611 void hugetlb_unregister_node(struct node *node) 1612 { 1613 struct hstate *h; 1614 struct node_hstate *nhs = &node_hstates[node->sysdev.id]; 1615 1616 if (!nhs->hugepages_kobj) 1617 return; /* no hstate attributes */ 1618 1619 for_each_hstate(h) 1620 if (nhs->hstate_kobjs[h - hstates]) { 1621 kobject_put(nhs->hstate_kobjs[h - hstates]); 1622 nhs->hstate_kobjs[h - hstates] = NULL; 1623 } 1624 1625 kobject_put(nhs->hugepages_kobj); 1626 nhs->hugepages_kobj = NULL; 1627 } 1628 1629 /* 1630 * hugetlb module exit: unregister hstate attributes from node sysdevs 1631 * that have them. 1632 */ 1633 static void hugetlb_unregister_all_nodes(void) 1634 { 1635 int nid; 1636 1637 /* 1638 * disable node sysdev registrations. 1639 */ 1640 register_hugetlbfs_with_node(NULL, NULL); 1641 1642 /* 1643 * remove hstate attributes from any nodes that have them. 1644 */ 1645 for (nid = 0; nid < nr_node_ids; nid++) 1646 hugetlb_unregister_node(&node_devices[nid]); 1647 } 1648 1649 /* 1650 * Register hstate attributes for a single node sysdev. 1651 * No-op if attributes already registered. 1652 */ 1653 void hugetlb_register_node(struct node *node) 1654 { 1655 struct hstate *h; 1656 struct node_hstate *nhs = &node_hstates[node->sysdev.id]; 1657 int err; 1658 1659 if (nhs->hugepages_kobj) 1660 return; /* already allocated */ 1661 1662 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1663 &node->sysdev.kobj); 1664 if (!nhs->hugepages_kobj) 1665 return; 1666 1667 for_each_hstate(h) { 1668 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1669 nhs->hstate_kobjs, 1670 &per_node_hstate_attr_group); 1671 if (err) { 1672 printk(KERN_ERR "Hugetlb: Unable to add hstate %s" 1673 " for node %d\n", 1674 h->name, node->sysdev.id); 1675 hugetlb_unregister_node(node); 1676 break; 1677 } 1678 } 1679 } 1680 1681 /* 1682 * hugetlb init time: register hstate attributes for all registered node 1683 * sysdevs of nodes that have memory. All on-line nodes should have 1684 * registered their associated sysdev by this time. 1685 */ 1686 static void hugetlb_register_all_nodes(void) 1687 { 1688 int nid; 1689 1690 for_each_node_state(nid, N_HIGH_MEMORY) { 1691 struct node *node = &node_devices[nid]; 1692 if (node->sysdev.id == nid) 1693 hugetlb_register_node(node); 1694 } 1695 1696 /* 1697 * Let the node sysdev driver know we're here so it can 1698 * [un]register hstate attributes on node hotplug. 1699 */ 1700 register_hugetlbfs_with_node(hugetlb_register_node, 1701 hugetlb_unregister_node); 1702 } 1703 #else /* !CONFIG_NUMA */ 1704 1705 static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1706 { 1707 BUG(); 1708 if (nidp) 1709 *nidp = -1; 1710 return NULL; 1711 } 1712 1713 static void hugetlb_unregister_all_nodes(void) { } 1714 1715 static void hugetlb_register_all_nodes(void) { } 1716 1717 #endif 1718 1719 static void __exit hugetlb_exit(void) 1720 { 1721 struct hstate *h; 1722 1723 hugetlb_unregister_all_nodes(); 1724 1725 for_each_hstate(h) { 1726 kobject_put(hstate_kobjs[h - hstates]); 1727 } 1728 1729 kobject_put(hugepages_kobj); 1730 } 1731 module_exit(hugetlb_exit); 1732 1733 static int __init hugetlb_init(void) 1734 { 1735 /* Some platform decide whether they support huge pages at boot 1736 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1737 * there is no such support 1738 */ 1739 if (HPAGE_SHIFT == 0) 1740 return 0; 1741 1742 if (!size_to_hstate(default_hstate_size)) { 1743 default_hstate_size = HPAGE_SIZE; 1744 if (!size_to_hstate(default_hstate_size)) 1745 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1746 } 1747 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; 1748 if (default_hstate_max_huge_pages) 1749 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1750 1751 hugetlb_init_hstates(); 1752 1753 gather_bootmem_prealloc(); 1754 1755 report_hugepages(); 1756 1757 hugetlb_sysfs_init(); 1758 1759 hugetlb_register_all_nodes(); 1760 1761 return 0; 1762 } 1763 module_init(hugetlb_init); 1764 1765 /* Should be called on processing a hugepagesz=... option */ 1766 void __init hugetlb_add_hstate(unsigned order) 1767 { 1768 struct hstate *h; 1769 unsigned long i; 1770 1771 if (size_to_hstate(PAGE_SIZE << order)) { 1772 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1773 return; 1774 } 1775 BUG_ON(max_hstate >= HUGE_MAX_HSTATE); 1776 BUG_ON(order == 0); 1777 h = &hstates[max_hstate++]; 1778 h->order = order; 1779 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1780 h->nr_huge_pages = 0; 1781 h->free_huge_pages = 0; 1782 for (i = 0; i < MAX_NUMNODES; ++i) 1783 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1784 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]); 1785 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]); 1786 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1787 huge_page_size(h)/1024); 1788 1789 parsed_hstate = h; 1790 } 1791 1792 static int __init hugetlb_nrpages_setup(char *s) 1793 { 1794 unsigned long *mhp; 1795 static unsigned long *last_mhp; 1796 1797 /* 1798 * !max_hstate means we haven't parsed a hugepagesz= parameter yet, 1799 * so this hugepages= parameter goes to the "default hstate". 1800 */ 1801 if (!max_hstate) 1802 mhp = &default_hstate_max_huge_pages; 1803 else 1804 mhp = &parsed_hstate->max_huge_pages; 1805 1806 if (mhp == last_mhp) { 1807 printk(KERN_WARNING "hugepages= specified twice without " 1808 "interleaving hugepagesz=, ignoring\n"); 1809 return 1; 1810 } 1811 1812 if (sscanf(s, "%lu", mhp) <= 0) 1813 *mhp = 0; 1814 1815 /* 1816 * Global state is always initialized later in hugetlb_init. 1817 * But we need to allocate >= MAX_ORDER hstates here early to still 1818 * use the bootmem allocator. 1819 */ 1820 if (max_hstate && parsed_hstate->order >= MAX_ORDER) 1821 hugetlb_hstate_alloc_pages(parsed_hstate); 1822 1823 last_mhp = mhp; 1824 1825 return 1; 1826 } 1827 __setup("hugepages=", hugetlb_nrpages_setup); 1828 1829 static int __init hugetlb_default_setup(char *s) 1830 { 1831 default_hstate_size = memparse(s, &s); 1832 return 1; 1833 } 1834 __setup("default_hugepagesz=", hugetlb_default_setup); 1835 1836 static unsigned int cpuset_mems_nr(unsigned int *array) 1837 { 1838 int node; 1839 unsigned int nr = 0; 1840 1841 for_each_node_mask(node, cpuset_current_mems_allowed) 1842 nr += array[node]; 1843 1844 return nr; 1845 } 1846 1847 #ifdef CONFIG_SYSCTL 1848 static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 1849 struct ctl_table *table, int write, 1850 void __user *buffer, size_t *length, loff_t *ppos) 1851 { 1852 struct hstate *h = &default_hstate; 1853 unsigned long tmp; 1854 1855 if (!write) 1856 tmp = h->max_huge_pages; 1857 1858 table->data = &tmp; 1859 table->maxlen = sizeof(unsigned long); 1860 proc_doulongvec_minmax(table, write, buffer, length, ppos); 1861 1862 if (write) { 1863 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 1864 GFP_KERNEL | __GFP_NORETRY); 1865 if (!(obey_mempolicy && 1866 init_nodemask_of_mempolicy(nodes_allowed))) { 1867 NODEMASK_FREE(nodes_allowed); 1868 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1869 } 1870 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 1871 1872 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1873 NODEMASK_FREE(nodes_allowed); 1874 } 1875 1876 return 0; 1877 } 1878 1879 int hugetlb_sysctl_handler(struct ctl_table *table, int write, 1880 void __user *buffer, size_t *length, loff_t *ppos) 1881 { 1882 1883 return hugetlb_sysctl_handler_common(false, table, write, 1884 buffer, length, ppos); 1885 } 1886 1887 #ifdef CONFIG_NUMA 1888 int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 1889 void __user *buffer, size_t *length, loff_t *ppos) 1890 { 1891 return hugetlb_sysctl_handler_common(true, table, write, 1892 buffer, length, ppos); 1893 } 1894 #endif /* CONFIG_NUMA */ 1895 1896 int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 1897 void __user *buffer, 1898 size_t *length, loff_t *ppos) 1899 { 1900 proc_dointvec(table, write, buffer, length, ppos); 1901 if (hugepages_treat_as_movable) 1902 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 1903 else 1904 htlb_alloc_mask = GFP_HIGHUSER; 1905 return 0; 1906 } 1907 1908 int hugetlb_overcommit_handler(struct ctl_table *table, int write, 1909 void __user *buffer, 1910 size_t *length, loff_t *ppos) 1911 { 1912 struct hstate *h = &default_hstate; 1913 unsigned long tmp; 1914 1915 if (!write) 1916 tmp = h->nr_overcommit_huge_pages; 1917 1918 table->data = &tmp; 1919 table->maxlen = sizeof(unsigned long); 1920 proc_doulongvec_minmax(table, write, buffer, length, ppos); 1921 1922 if (write) { 1923 spin_lock(&hugetlb_lock); 1924 h->nr_overcommit_huge_pages = tmp; 1925 spin_unlock(&hugetlb_lock); 1926 } 1927 1928 return 0; 1929 } 1930 1931 #endif /* CONFIG_SYSCTL */ 1932 1933 void hugetlb_report_meminfo(struct seq_file *m) 1934 { 1935 struct hstate *h = &default_hstate; 1936 seq_printf(m, 1937 "HugePages_Total: %5lu\n" 1938 "HugePages_Free: %5lu\n" 1939 "HugePages_Rsvd: %5lu\n" 1940 "HugePages_Surp: %5lu\n" 1941 "Hugepagesize: %8lu kB\n", 1942 h->nr_huge_pages, 1943 h->free_huge_pages, 1944 h->resv_huge_pages, 1945 h->surplus_huge_pages, 1946 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 1947 } 1948 1949 int hugetlb_report_node_meminfo(int nid, char *buf) 1950 { 1951 struct hstate *h = &default_hstate; 1952 return sprintf(buf, 1953 "Node %d HugePages_Total: %5u\n" 1954 "Node %d HugePages_Free: %5u\n" 1955 "Node %d HugePages_Surp: %5u\n", 1956 nid, h->nr_huge_pages_node[nid], 1957 nid, h->free_huge_pages_node[nid], 1958 nid, h->surplus_huge_pages_node[nid]); 1959 } 1960 1961 /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 1962 unsigned long hugetlb_total_pages(void) 1963 { 1964 struct hstate *h = &default_hstate; 1965 return h->nr_huge_pages * pages_per_huge_page(h); 1966 } 1967 1968 static int hugetlb_acct_memory(struct hstate *h, long delta) 1969 { 1970 int ret = -ENOMEM; 1971 1972 spin_lock(&hugetlb_lock); 1973 /* 1974 * When cpuset is configured, it breaks the strict hugetlb page 1975 * reservation as the accounting is done on a global variable. Such 1976 * reservation is completely rubbish in the presence of cpuset because 1977 * the reservation is not checked against page availability for the 1978 * current cpuset. Application can still potentially OOM'ed by kernel 1979 * with lack of free htlb page in cpuset that the task is in. 1980 * Attempt to enforce strict accounting with cpuset is almost 1981 * impossible (or too ugly) because cpuset is too fluid that 1982 * task or memory node can be dynamically moved between cpusets. 1983 * 1984 * The change of semantics for shared hugetlb mapping with cpuset is 1985 * undesirable. However, in order to preserve some of the semantics, 1986 * we fall back to check against current free page availability as 1987 * a best attempt and hopefully to minimize the impact of changing 1988 * semantics that cpuset has. 1989 */ 1990 if (delta > 0) { 1991 if (gather_surplus_pages(h, delta) < 0) 1992 goto out; 1993 1994 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 1995 return_unused_surplus_pages(h, delta); 1996 goto out; 1997 } 1998 } 1999 2000 ret = 0; 2001 if (delta < 0) 2002 return_unused_surplus_pages(h, (unsigned long) -delta); 2003 2004 out: 2005 spin_unlock(&hugetlb_lock); 2006 return ret; 2007 } 2008 2009 static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2010 { 2011 struct resv_map *reservations = vma_resv_map(vma); 2012 2013 /* 2014 * This new VMA should share its siblings reservation map if present. 2015 * The VMA will only ever have a valid reservation map pointer where 2016 * it is being copied for another still existing VMA. As that VMA 2017 * has a reference to the reservation map it cannot dissappear until 2018 * after this open call completes. It is therefore safe to take a 2019 * new reference here without additional locking. 2020 */ 2021 if (reservations) 2022 kref_get(&reservations->refs); 2023 } 2024 2025 static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2026 { 2027 struct hstate *h = hstate_vma(vma); 2028 struct resv_map *reservations = vma_resv_map(vma); 2029 unsigned long reserve; 2030 unsigned long start; 2031 unsigned long end; 2032 2033 if (reservations) { 2034 start = vma_hugecache_offset(h, vma, vma->vm_start); 2035 end = vma_hugecache_offset(h, vma, vma->vm_end); 2036 2037 reserve = (end - start) - 2038 region_count(&reservations->regions, start, end); 2039 2040 kref_put(&reservations->refs, resv_map_release); 2041 2042 if (reserve) { 2043 hugetlb_acct_memory(h, -reserve); 2044 hugetlb_put_quota(vma->vm_file->f_mapping, reserve); 2045 } 2046 } 2047 } 2048 2049 /* 2050 * We cannot handle pagefaults against hugetlb pages at all. They cause 2051 * handle_mm_fault() to try to instantiate regular-sized pages in the 2052 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2053 * this far. 2054 */ 2055 static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2056 { 2057 BUG(); 2058 return 0; 2059 } 2060 2061 const struct vm_operations_struct hugetlb_vm_ops = { 2062 .fault = hugetlb_vm_op_fault, 2063 .open = hugetlb_vm_op_open, 2064 .close = hugetlb_vm_op_close, 2065 }; 2066 2067 static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2068 int writable) 2069 { 2070 pte_t entry; 2071 2072 if (writable) { 2073 entry = 2074 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 2075 } else { 2076 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 2077 } 2078 entry = pte_mkyoung(entry); 2079 entry = pte_mkhuge(entry); 2080 2081 return entry; 2082 } 2083 2084 static void set_huge_ptep_writable(struct vm_area_struct *vma, 2085 unsigned long address, pte_t *ptep) 2086 { 2087 pte_t entry; 2088 2089 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 2090 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { 2091 update_mmu_cache(vma, address, entry); 2092 } 2093 } 2094 2095 2096 int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2097 struct vm_area_struct *vma) 2098 { 2099 pte_t *src_pte, *dst_pte, entry; 2100 struct page *ptepage; 2101 unsigned long addr; 2102 int cow; 2103 struct hstate *h = hstate_vma(vma); 2104 unsigned long sz = huge_page_size(h); 2105 2106 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2107 2108 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2109 src_pte = huge_pte_offset(src, addr); 2110 if (!src_pte) 2111 continue; 2112 dst_pte = huge_pte_alloc(dst, addr, sz); 2113 if (!dst_pte) 2114 goto nomem; 2115 2116 /* If the pagetables are shared don't copy or take references */ 2117 if (dst_pte == src_pte) 2118 continue; 2119 2120 spin_lock(&dst->page_table_lock); 2121 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 2122 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2123 if (cow) 2124 huge_ptep_set_wrprotect(src, addr, src_pte); 2125 entry = huge_ptep_get(src_pte); 2126 ptepage = pte_page(entry); 2127 get_page(ptepage); 2128 set_huge_pte_at(dst, addr, dst_pte, entry); 2129 } 2130 spin_unlock(&src->page_table_lock); 2131 spin_unlock(&dst->page_table_lock); 2132 } 2133 return 0; 2134 2135 nomem: 2136 return -ENOMEM; 2137 } 2138 2139 void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2140 unsigned long end, struct page *ref_page) 2141 { 2142 struct mm_struct *mm = vma->vm_mm; 2143 unsigned long address; 2144 pte_t *ptep; 2145 pte_t pte; 2146 struct page *page; 2147 struct page *tmp; 2148 struct hstate *h = hstate_vma(vma); 2149 unsigned long sz = huge_page_size(h); 2150 2151 /* 2152 * A page gathering list, protected by per file i_mmap_lock. The 2153 * lock is used to avoid list corruption from multiple unmapping 2154 * of the same page since we are using page->lru. 2155 */ 2156 LIST_HEAD(page_list); 2157 2158 WARN_ON(!is_vm_hugetlb_page(vma)); 2159 BUG_ON(start & ~huge_page_mask(h)); 2160 BUG_ON(end & ~huge_page_mask(h)); 2161 2162 mmu_notifier_invalidate_range_start(mm, start, end); 2163 spin_lock(&mm->page_table_lock); 2164 for (address = start; address < end; address += sz) { 2165 ptep = huge_pte_offset(mm, address); 2166 if (!ptep) 2167 continue; 2168 2169 if (huge_pmd_unshare(mm, &address, ptep)) 2170 continue; 2171 2172 /* 2173 * If a reference page is supplied, it is because a specific 2174 * page is being unmapped, not a range. Ensure the page we 2175 * are about to unmap is the actual page of interest. 2176 */ 2177 if (ref_page) { 2178 pte = huge_ptep_get(ptep); 2179 if (huge_pte_none(pte)) 2180 continue; 2181 page = pte_page(pte); 2182 if (page != ref_page) 2183 continue; 2184 2185 /* 2186 * Mark the VMA as having unmapped its page so that 2187 * future faults in this VMA will fail rather than 2188 * looking like data was lost 2189 */ 2190 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2191 } 2192 2193 pte = huge_ptep_get_and_clear(mm, address, ptep); 2194 if (huge_pte_none(pte)) 2195 continue; 2196 2197 page = pte_page(pte); 2198 if (pte_dirty(pte)) 2199 set_page_dirty(page); 2200 list_add(&page->lru, &page_list); 2201 } 2202 spin_unlock(&mm->page_table_lock); 2203 flush_tlb_range(vma, start, end); 2204 mmu_notifier_invalidate_range_end(mm, start, end); 2205 list_for_each_entry_safe(page, tmp, &page_list, lru) { 2206 list_del(&page->lru); 2207 put_page(page); 2208 } 2209 } 2210 2211 void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2212 unsigned long end, struct page *ref_page) 2213 { 2214 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2215 __unmap_hugepage_range(vma, start, end, ref_page); 2216 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2217 } 2218 2219 /* 2220 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2221 * mappping it owns the reserve page for. The intention is to unmap the page 2222 * from other VMAs and let the children be SIGKILLed if they are faulting the 2223 * same region. 2224 */ 2225 static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2226 struct page *page, unsigned long address) 2227 { 2228 struct hstate *h = hstate_vma(vma); 2229 struct vm_area_struct *iter_vma; 2230 struct address_space *mapping; 2231 struct prio_tree_iter iter; 2232 pgoff_t pgoff; 2233 2234 /* 2235 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2236 * from page cache lookup which is in HPAGE_SIZE units. 2237 */ 2238 address = address & huge_page_mask(h); 2239 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) 2240 + (vma->vm_pgoff >> PAGE_SHIFT); 2241 mapping = (struct address_space *)page_private(page); 2242 2243 /* 2244 * Take the mapping lock for the duration of the table walk. As 2245 * this mapping should be shared between all the VMAs, 2246 * __unmap_hugepage_range() is called as the lock is already held 2247 */ 2248 spin_lock(&mapping->i_mmap_lock); 2249 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { 2250 /* Do not unmap the current VMA */ 2251 if (iter_vma == vma) 2252 continue; 2253 2254 /* 2255 * Unmap the page from other VMAs without their own reserves. 2256 * They get marked to be SIGKILLed if they fault in these 2257 * areas. This is because a future no-page fault on this VMA 2258 * could insert a zeroed page instead of the data existing 2259 * from the time of fork. This would look like data corruption 2260 */ 2261 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2262 __unmap_hugepage_range(iter_vma, 2263 address, address + huge_page_size(h), 2264 page); 2265 } 2266 spin_unlock(&mapping->i_mmap_lock); 2267 2268 return 1; 2269 } 2270 2271 static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2272 unsigned long address, pte_t *ptep, pte_t pte, 2273 struct page *pagecache_page) 2274 { 2275 struct hstate *h = hstate_vma(vma); 2276 struct page *old_page, *new_page; 2277 int avoidcopy; 2278 int outside_reserve = 0; 2279 2280 old_page = pte_page(pte); 2281 2282 retry_avoidcopy: 2283 /* If no-one else is actually using this page, avoid the copy 2284 * and just make the page writable */ 2285 avoidcopy = (page_count(old_page) == 1); 2286 if (avoidcopy) { 2287 set_huge_ptep_writable(vma, address, ptep); 2288 return 0; 2289 } 2290 2291 /* 2292 * If the process that created a MAP_PRIVATE mapping is about to 2293 * perform a COW due to a shared page count, attempt to satisfy 2294 * the allocation without using the existing reserves. The pagecache 2295 * page is used to determine if the reserve at this address was 2296 * consumed or not. If reserves were used, a partial faulted mapping 2297 * at the time of fork() could consume its reserves on COW instead 2298 * of the full address range. 2299 */ 2300 if (!(vma->vm_flags & VM_MAYSHARE) && 2301 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2302 old_page != pagecache_page) 2303 outside_reserve = 1; 2304 2305 page_cache_get(old_page); 2306 2307 /* Drop page_table_lock as buddy allocator may be called */ 2308 spin_unlock(&mm->page_table_lock); 2309 new_page = alloc_huge_page(vma, address, outside_reserve); 2310 2311 if (IS_ERR(new_page)) { 2312 page_cache_release(old_page); 2313 2314 /* 2315 * If a process owning a MAP_PRIVATE mapping fails to COW, 2316 * it is due to references held by a child and an insufficient 2317 * huge page pool. To guarantee the original mappers 2318 * reliability, unmap the page from child processes. The child 2319 * may get SIGKILLed if it later faults. 2320 */ 2321 if (outside_reserve) { 2322 BUG_ON(huge_pte_none(pte)); 2323 if (unmap_ref_private(mm, vma, old_page, address)) { 2324 BUG_ON(page_count(old_page) != 1); 2325 BUG_ON(huge_pte_none(pte)); 2326 spin_lock(&mm->page_table_lock); 2327 goto retry_avoidcopy; 2328 } 2329 WARN_ON_ONCE(1); 2330 } 2331 2332 /* Caller expects lock to be held */ 2333 spin_lock(&mm->page_table_lock); 2334 return -PTR_ERR(new_page); 2335 } 2336 2337 copy_huge_page(new_page, old_page, address, vma); 2338 __SetPageUptodate(new_page); 2339 2340 /* 2341 * Retake the page_table_lock to check for racing updates 2342 * before the page tables are altered 2343 */ 2344 spin_lock(&mm->page_table_lock); 2345 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2346 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2347 /* Break COW */ 2348 huge_ptep_clear_flush(vma, address, ptep); 2349 set_huge_pte_at(mm, address, ptep, 2350 make_huge_pte(vma, new_page, 1)); 2351 /* Make the old page be freed below */ 2352 new_page = old_page; 2353 } 2354 page_cache_release(new_page); 2355 page_cache_release(old_page); 2356 return 0; 2357 } 2358 2359 /* Return the pagecache page at a given address within a VMA */ 2360 static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2361 struct vm_area_struct *vma, unsigned long address) 2362 { 2363 struct address_space *mapping; 2364 pgoff_t idx; 2365 2366 mapping = vma->vm_file->f_mapping; 2367 idx = vma_hugecache_offset(h, vma, address); 2368 2369 return find_lock_page(mapping, idx); 2370 } 2371 2372 /* 2373 * Return whether there is a pagecache page to back given address within VMA. 2374 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2375 */ 2376 static bool hugetlbfs_pagecache_present(struct hstate *h, 2377 struct vm_area_struct *vma, unsigned long address) 2378 { 2379 struct address_space *mapping; 2380 pgoff_t idx; 2381 struct page *page; 2382 2383 mapping = vma->vm_file->f_mapping; 2384 idx = vma_hugecache_offset(h, vma, address); 2385 2386 page = find_get_page(mapping, idx); 2387 if (page) 2388 put_page(page); 2389 return page != NULL; 2390 } 2391 2392 static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2393 unsigned long address, pte_t *ptep, unsigned int flags) 2394 { 2395 struct hstate *h = hstate_vma(vma); 2396 int ret = VM_FAULT_SIGBUS; 2397 pgoff_t idx; 2398 unsigned long size; 2399 struct page *page; 2400 struct address_space *mapping; 2401 pte_t new_pte; 2402 2403 /* 2404 * Currently, we are forced to kill the process in the event the 2405 * original mapper has unmapped pages from the child due to a failed 2406 * COW. Warn that such a situation has occured as it may not be obvious 2407 */ 2408 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2409 printk(KERN_WARNING 2410 "PID %d killed due to inadequate hugepage pool\n", 2411 current->pid); 2412 return ret; 2413 } 2414 2415 mapping = vma->vm_file->f_mapping; 2416 idx = vma_hugecache_offset(h, vma, address); 2417 2418 /* 2419 * Use page lock to guard against racing truncation 2420 * before we get page_table_lock. 2421 */ 2422 retry: 2423 page = find_lock_page(mapping, idx); 2424 if (!page) { 2425 size = i_size_read(mapping->host) >> huge_page_shift(h); 2426 if (idx >= size) 2427 goto out; 2428 page = alloc_huge_page(vma, address, 0); 2429 if (IS_ERR(page)) { 2430 ret = -PTR_ERR(page); 2431 goto out; 2432 } 2433 clear_huge_page(page, address, huge_page_size(h)); 2434 __SetPageUptodate(page); 2435 2436 if (vma->vm_flags & VM_MAYSHARE) { 2437 int err; 2438 struct inode *inode = mapping->host; 2439 2440 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2441 if (err) { 2442 put_page(page); 2443 if (err == -EEXIST) 2444 goto retry; 2445 goto out; 2446 } 2447 2448 spin_lock(&inode->i_lock); 2449 inode->i_blocks += blocks_per_huge_page(h); 2450 spin_unlock(&inode->i_lock); 2451 } else 2452 lock_page(page); 2453 } 2454 2455 /* 2456 * If we are going to COW a private mapping later, we examine the 2457 * pending reservations for this page now. This will ensure that 2458 * any allocations necessary to record that reservation occur outside 2459 * the spinlock. 2460 */ 2461 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2462 if (vma_needs_reservation(h, vma, address) < 0) { 2463 ret = VM_FAULT_OOM; 2464 goto backout_unlocked; 2465 } 2466 2467 spin_lock(&mm->page_table_lock); 2468 size = i_size_read(mapping->host) >> huge_page_shift(h); 2469 if (idx >= size) 2470 goto backout; 2471 2472 ret = 0; 2473 if (!huge_pte_none(huge_ptep_get(ptep))) 2474 goto backout; 2475 2476 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2477 && (vma->vm_flags & VM_SHARED))); 2478 set_huge_pte_at(mm, address, ptep, new_pte); 2479 2480 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2481 /* Optimization, do the COW without a second fault */ 2482 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2483 } 2484 2485 spin_unlock(&mm->page_table_lock); 2486 unlock_page(page); 2487 out: 2488 return ret; 2489 2490 backout: 2491 spin_unlock(&mm->page_table_lock); 2492 backout_unlocked: 2493 unlock_page(page); 2494 put_page(page); 2495 goto out; 2496 } 2497 2498 int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2499 unsigned long address, unsigned int flags) 2500 { 2501 pte_t *ptep; 2502 pte_t entry; 2503 int ret; 2504 struct page *pagecache_page = NULL; 2505 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2506 struct hstate *h = hstate_vma(vma); 2507 2508 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2509 if (!ptep) 2510 return VM_FAULT_OOM; 2511 2512 /* 2513 * Serialize hugepage allocation and instantiation, so that we don't 2514 * get spurious allocation failures if two CPUs race to instantiate 2515 * the same page in the page cache. 2516 */ 2517 mutex_lock(&hugetlb_instantiation_mutex); 2518 entry = huge_ptep_get(ptep); 2519 if (huge_pte_none(entry)) { 2520 ret = hugetlb_no_page(mm, vma, address, ptep, flags); 2521 goto out_mutex; 2522 } 2523 2524 ret = 0; 2525 2526 /* 2527 * If we are going to COW the mapping later, we examine the pending 2528 * reservations for this page now. This will ensure that any 2529 * allocations necessary to record that reservation occur outside the 2530 * spinlock. For private mappings, we also lookup the pagecache 2531 * page now as it is used to determine if a reservation has been 2532 * consumed. 2533 */ 2534 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) { 2535 if (vma_needs_reservation(h, vma, address) < 0) { 2536 ret = VM_FAULT_OOM; 2537 goto out_mutex; 2538 } 2539 2540 if (!(vma->vm_flags & VM_MAYSHARE)) 2541 pagecache_page = hugetlbfs_pagecache_page(h, 2542 vma, address); 2543 } 2544 2545 spin_lock(&mm->page_table_lock); 2546 /* Check for a racing update before calling hugetlb_cow */ 2547 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2548 goto out_page_table_lock; 2549 2550 2551 if (flags & FAULT_FLAG_WRITE) { 2552 if (!pte_write(entry)) { 2553 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2554 pagecache_page); 2555 goto out_page_table_lock; 2556 } 2557 entry = pte_mkdirty(entry); 2558 } 2559 entry = pte_mkyoung(entry); 2560 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 2561 flags & FAULT_FLAG_WRITE)) 2562 update_mmu_cache(vma, address, entry); 2563 2564 out_page_table_lock: 2565 spin_unlock(&mm->page_table_lock); 2566 2567 if (pagecache_page) { 2568 unlock_page(pagecache_page); 2569 put_page(pagecache_page); 2570 } 2571 2572 out_mutex: 2573 mutex_unlock(&hugetlb_instantiation_mutex); 2574 2575 return ret; 2576 } 2577 2578 /* Can be overriden by architectures */ 2579 __attribute__((weak)) struct page * 2580 follow_huge_pud(struct mm_struct *mm, unsigned long address, 2581 pud_t *pud, int write) 2582 { 2583 BUG(); 2584 return NULL; 2585 } 2586 2587 int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2588 struct page **pages, struct vm_area_struct **vmas, 2589 unsigned long *position, int *length, int i, 2590 unsigned int flags) 2591 { 2592 unsigned long pfn_offset; 2593 unsigned long vaddr = *position; 2594 int remainder = *length; 2595 struct hstate *h = hstate_vma(vma); 2596 2597 spin_lock(&mm->page_table_lock); 2598 while (vaddr < vma->vm_end && remainder) { 2599 pte_t *pte; 2600 int absent; 2601 struct page *page; 2602 2603 /* 2604 * Some archs (sparc64, sh*) have multiple pte_ts to 2605 * each hugepage. We have to make sure we get the 2606 * first, for the page indexing below to work. 2607 */ 2608 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2609 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 2610 2611 /* 2612 * When coredumping, it suits get_dump_page if we just return 2613 * an error where there's an empty slot with no huge pagecache 2614 * to back it. This way, we avoid allocating a hugepage, and 2615 * the sparse dumpfile avoids allocating disk blocks, but its 2616 * huge holes still show up with zeroes where they need to be. 2617 */ 2618 if (absent && (flags & FOLL_DUMP) && 2619 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 2620 remainder = 0; 2621 break; 2622 } 2623 2624 if (absent || 2625 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) { 2626 int ret; 2627 2628 spin_unlock(&mm->page_table_lock); 2629 ret = hugetlb_fault(mm, vma, vaddr, 2630 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 2631 spin_lock(&mm->page_table_lock); 2632 if (!(ret & VM_FAULT_ERROR)) 2633 continue; 2634 2635 remainder = 0; 2636 break; 2637 } 2638 2639 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2640 page = pte_page(huge_ptep_get(pte)); 2641 same_page: 2642 if (pages) { 2643 pages[i] = mem_map_offset(page, pfn_offset); 2644 get_page(pages[i]); 2645 } 2646 2647 if (vmas) 2648 vmas[i] = vma; 2649 2650 vaddr += PAGE_SIZE; 2651 ++pfn_offset; 2652 --remainder; 2653 ++i; 2654 if (vaddr < vma->vm_end && remainder && 2655 pfn_offset < pages_per_huge_page(h)) { 2656 /* 2657 * We use pfn_offset to avoid touching the pageframes 2658 * of this compound page. 2659 */ 2660 goto same_page; 2661 } 2662 } 2663 spin_unlock(&mm->page_table_lock); 2664 *length = remainder; 2665 *position = vaddr; 2666 2667 return i ? i : -EFAULT; 2668 } 2669 2670 void hugetlb_change_protection(struct vm_area_struct *vma, 2671 unsigned long address, unsigned long end, pgprot_t newprot) 2672 { 2673 struct mm_struct *mm = vma->vm_mm; 2674 unsigned long start = address; 2675 pte_t *ptep; 2676 pte_t pte; 2677 struct hstate *h = hstate_vma(vma); 2678 2679 BUG_ON(address >= end); 2680 flush_cache_range(vma, address, end); 2681 2682 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2683 spin_lock(&mm->page_table_lock); 2684 for (; address < end; address += huge_page_size(h)) { 2685 ptep = huge_pte_offset(mm, address); 2686 if (!ptep) 2687 continue; 2688 if (huge_pmd_unshare(mm, &address, ptep)) 2689 continue; 2690 if (!huge_pte_none(huge_ptep_get(ptep))) { 2691 pte = huge_ptep_get_and_clear(mm, address, ptep); 2692 pte = pte_mkhuge(pte_modify(pte, newprot)); 2693 set_huge_pte_at(mm, address, ptep, pte); 2694 } 2695 } 2696 spin_unlock(&mm->page_table_lock); 2697 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2698 2699 flush_tlb_range(vma, start, end); 2700 } 2701 2702 int hugetlb_reserve_pages(struct inode *inode, 2703 long from, long to, 2704 struct vm_area_struct *vma, 2705 int acctflag) 2706 { 2707 long ret, chg; 2708 struct hstate *h = hstate_inode(inode); 2709 2710 /* 2711 * Only apply hugepage reservation if asked. At fault time, an 2712 * attempt will be made for VM_NORESERVE to allocate a page 2713 * and filesystem quota without using reserves 2714 */ 2715 if (acctflag & VM_NORESERVE) 2716 return 0; 2717 2718 /* 2719 * Shared mappings base their reservation on the number of pages that 2720 * are already allocated on behalf of the file. Private mappings need 2721 * to reserve the full area even if read-only as mprotect() may be 2722 * called to make the mapping read-write. Assume !vma is a shm mapping 2723 */ 2724 if (!vma || vma->vm_flags & VM_MAYSHARE) 2725 chg = region_chg(&inode->i_mapping->private_list, from, to); 2726 else { 2727 struct resv_map *resv_map = resv_map_alloc(); 2728 if (!resv_map) 2729 return -ENOMEM; 2730 2731 chg = to - from; 2732 2733 set_vma_resv_map(vma, resv_map); 2734 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 2735 } 2736 2737 if (chg < 0) 2738 return chg; 2739 2740 /* There must be enough filesystem quota for the mapping */ 2741 if (hugetlb_get_quota(inode->i_mapping, chg)) 2742 return -ENOSPC; 2743 2744 /* 2745 * Check enough hugepages are available for the reservation. 2746 * Hand back the quota if there are not 2747 */ 2748 ret = hugetlb_acct_memory(h, chg); 2749 if (ret < 0) { 2750 hugetlb_put_quota(inode->i_mapping, chg); 2751 return ret; 2752 } 2753 2754 /* 2755 * Account for the reservations made. Shared mappings record regions 2756 * that have reservations as they are shared by multiple VMAs. 2757 * When the last VMA disappears, the region map says how much 2758 * the reservation was and the page cache tells how much of 2759 * the reservation was consumed. Private mappings are per-VMA and 2760 * only the consumed reservations are tracked. When the VMA 2761 * disappears, the original reservation is the VMA size and the 2762 * consumed reservations are stored in the map. Hence, nothing 2763 * else has to be done for private mappings here 2764 */ 2765 if (!vma || vma->vm_flags & VM_MAYSHARE) 2766 region_add(&inode->i_mapping->private_list, from, to); 2767 return 0; 2768 } 2769 2770 void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 2771 { 2772 struct hstate *h = hstate_inode(inode); 2773 long chg = region_truncate(&inode->i_mapping->private_list, offset); 2774 2775 spin_lock(&inode->i_lock); 2776 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 2777 spin_unlock(&inode->i_lock); 2778 2779 hugetlb_put_quota(inode->i_mapping, (chg - freed)); 2780 hugetlb_acct_memory(h, -(chg - freed)); 2781 } 2782