hugetlb.c revision 6de2b1aab94355482bd2accdc115666509667458
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#include <linux/rmap.h> 22#include <linux/swap.h> 23#include <linux/swapops.h> 24 25#include <asm/page.h> 26#include <asm/pgtable.h> 27#include <asm/io.h> 28 29#include <linux/hugetlb.h> 30#include <linux/node.h> 31#include "internal.h" 32 33const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 34static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 35unsigned long hugepages_treat_as_movable; 36 37static int max_hstate; 38unsigned int default_hstate_idx; 39struct hstate hstates[HUGE_MAX_HSTATE]; 40 41__initdata LIST_HEAD(huge_boot_pages); 42 43/* for command line parsing */ 44static struct hstate * __initdata parsed_hstate; 45static unsigned long __initdata default_hstate_max_huge_pages; 46static unsigned long __initdata default_hstate_size; 47 48#define for_each_hstate(h) \ 49 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) 50 51/* 52 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages 53 */ 54static DEFINE_SPINLOCK(hugetlb_lock); 55 56/* 57 * Region tracking -- allows tracking of reservations and instantiated pages 58 * across the pages in a mapping. 59 * 60 * The region data structures are protected by a combination of the mmap_sem 61 * and the hugetlb_instantion_mutex. To access or modify a region the caller 62 * must either hold the mmap_sem for write, or the mmap_sem for read and 63 * the hugetlb_instantiation mutex: 64 * 65 * down_write(&mm->mmap_sem); 66 * or 67 * down_read(&mm->mmap_sem); 68 * mutex_lock(&hugetlb_instantiation_mutex); 69 */ 70struct file_region { 71 struct list_head link; 72 long from; 73 long to; 74}; 75 76static long region_add(struct list_head *head, long f, long t) 77{ 78 struct file_region *rg, *nrg, *trg; 79 80 /* Locate the region we are either in or before. */ 81 list_for_each_entry(rg, head, link) 82 if (f <= rg->to) 83 break; 84 85 /* Round our left edge to the current segment if it encloses us. */ 86 if (f > rg->from) 87 f = rg->from; 88 89 /* Check for and consume any regions we now overlap with. */ 90 nrg = rg; 91 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 92 if (&rg->link == head) 93 break; 94 if (rg->from > t) 95 break; 96 97 /* If this area reaches higher then extend our area to 98 * include it completely. If this is not the first area 99 * which we intend to reuse, free it. */ 100 if (rg->to > t) 101 t = rg->to; 102 if (rg != nrg) { 103 list_del(&rg->link); 104 kfree(rg); 105 } 106 } 107 nrg->from = f; 108 nrg->to = t; 109 return 0; 110} 111 112static long region_chg(struct list_head *head, long f, long t) 113{ 114 struct file_region *rg, *nrg; 115 long chg = 0; 116 117 /* Locate the region we are before or in. */ 118 list_for_each_entry(rg, head, link) 119 if (f <= rg->to) 120 break; 121 122 /* If we are below the current region then a new region is required. 123 * Subtle, allocate a new region at the position but make it zero 124 * size such that we can guarantee to record the reservation. */ 125 if (&rg->link == head || t < rg->from) { 126 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 127 if (!nrg) 128 return -ENOMEM; 129 nrg->from = f; 130 nrg->to = f; 131 INIT_LIST_HEAD(&nrg->link); 132 list_add(&nrg->link, rg->link.prev); 133 134 return t - f; 135 } 136 137 /* Round our left edge to the current segment if it encloses us. */ 138 if (f > rg->from) 139 f = rg->from; 140 chg = t - f; 141 142 /* Check for and consume any regions we now overlap with. */ 143 list_for_each_entry(rg, rg->link.prev, link) { 144 if (&rg->link == head) 145 break; 146 if (rg->from > t) 147 return chg; 148 149 /* We overlap with this area, if it extends futher than 150 * us then we must extend ourselves. Account for its 151 * existing reservation. */ 152 if (rg->to > t) { 153 chg += rg->to - t; 154 t = rg->to; 155 } 156 chg -= rg->to - rg->from; 157 } 158 return chg; 159} 160 161static long region_truncate(struct list_head *head, long end) 162{ 163 struct file_region *rg, *trg; 164 long chg = 0; 165 166 /* Locate the region we are either in or before. */ 167 list_for_each_entry(rg, head, link) 168 if (end <= rg->to) 169 break; 170 if (&rg->link == head) 171 return 0; 172 173 /* If we are in the middle of a region then adjust it. */ 174 if (end > rg->from) { 175 chg = rg->to - end; 176 rg->to = end; 177 rg = list_entry(rg->link.next, typeof(*rg), link); 178 } 179 180 /* Drop any remaining regions. */ 181 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 182 if (&rg->link == head) 183 break; 184 chg += rg->to - rg->from; 185 list_del(&rg->link); 186 kfree(rg); 187 } 188 return chg; 189} 190 191static long region_count(struct list_head *head, long f, long t) 192{ 193 struct file_region *rg; 194 long chg = 0; 195 196 /* Locate each segment we overlap with, and count that overlap. */ 197 list_for_each_entry(rg, head, link) { 198 int seg_from; 199 int seg_to; 200 201 if (rg->to <= f) 202 continue; 203 if (rg->from >= t) 204 break; 205 206 seg_from = max(rg->from, f); 207 seg_to = min(rg->to, t); 208 209 chg += seg_to - seg_from; 210 } 211 212 return chg; 213} 214 215/* 216 * Convert the address within this vma to the page offset within 217 * the mapping, in pagecache page units; huge pages here. 218 */ 219static pgoff_t vma_hugecache_offset(struct hstate *h, 220 struct vm_area_struct *vma, unsigned long address) 221{ 222 return ((address - vma->vm_start) >> huge_page_shift(h)) + 223 (vma->vm_pgoff >> huge_page_order(h)); 224} 225 226pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 227 unsigned long address) 228{ 229 return vma_hugecache_offset(hstate_vma(vma), vma, address); 230} 231 232/* 233 * Return the size of the pages allocated when backing a VMA. In the majority 234 * cases this will be same size as used by the page table entries. 235 */ 236unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) 237{ 238 struct hstate *hstate; 239 240 if (!is_vm_hugetlb_page(vma)) 241 return PAGE_SIZE; 242 243 hstate = hstate_vma(vma); 244 245 return 1UL << (hstate->order + PAGE_SHIFT); 246} 247EXPORT_SYMBOL_GPL(vma_kernel_pagesize); 248 249/* 250 * Return the page size being used by the MMU to back a VMA. In the majority 251 * of cases, the page size used by the kernel matches the MMU size. On 252 * architectures where it differs, an architecture-specific version of this 253 * function is required. 254 */ 255#ifndef vma_mmu_pagesize 256unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 257{ 258 return vma_kernel_pagesize(vma); 259} 260#endif 261 262/* 263 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 264 * bits of the reservation map pointer, which are always clear due to 265 * alignment. 266 */ 267#define HPAGE_RESV_OWNER (1UL << 0) 268#define HPAGE_RESV_UNMAPPED (1UL << 1) 269#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 270 271/* 272 * These helpers are used to track how many pages are reserved for 273 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 274 * is guaranteed to have their future faults succeed. 275 * 276 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 277 * the reserve counters are updated with the hugetlb_lock held. It is safe 278 * to reset the VMA at fork() time as it is not in use yet and there is no 279 * chance of the global counters getting corrupted as a result of the values. 280 * 281 * The private mapping reservation is represented in a subtly different 282 * manner to a shared mapping. A shared mapping has a region map associated 283 * with the underlying file, this region map represents the backing file 284 * pages which have ever had a reservation assigned which this persists even 285 * after the page is instantiated. A private mapping has a region map 286 * associated with the original mmap which is attached to all VMAs which 287 * reference it, this region map represents those offsets which have consumed 288 * reservation ie. where pages have been instantiated. 289 */ 290static unsigned long get_vma_private_data(struct vm_area_struct *vma) 291{ 292 return (unsigned long)vma->vm_private_data; 293} 294 295static void set_vma_private_data(struct vm_area_struct *vma, 296 unsigned long value) 297{ 298 vma->vm_private_data = (void *)value; 299} 300 301struct resv_map { 302 struct kref refs; 303 struct list_head regions; 304}; 305 306static struct resv_map *resv_map_alloc(void) 307{ 308 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 309 if (!resv_map) 310 return NULL; 311 312 kref_init(&resv_map->refs); 313 INIT_LIST_HEAD(&resv_map->regions); 314 315 return resv_map; 316} 317 318static void resv_map_release(struct kref *ref) 319{ 320 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 321 322 /* Clear out any active regions before we release the map. */ 323 region_truncate(&resv_map->regions, 0); 324 kfree(resv_map); 325} 326 327static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 328{ 329 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 330 if (!(vma->vm_flags & VM_MAYSHARE)) 331 return (struct resv_map *)(get_vma_private_data(vma) & 332 ~HPAGE_RESV_MASK); 333 return NULL; 334} 335 336static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 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) & 342 HPAGE_RESV_MASK) | (unsigned long)map); 343} 344 345static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 346{ 347 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 348 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 349 350 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 351} 352 353static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 354{ 355 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 356 357 return (get_vma_private_data(vma) & flag) != 0; 358} 359 360/* Decrement the reserved pages in the hugepage pool by one */ 361static void decrement_hugepage_resv_vma(struct hstate *h, 362 struct vm_area_struct *vma) 363{ 364 if (vma->vm_flags & VM_NORESERVE) 365 return; 366 367 if (vma->vm_flags & VM_MAYSHARE) { 368 /* Shared mappings always use reserves */ 369 h->resv_huge_pages--; 370 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 371 /* 372 * Only the process that called mmap() has reserves for 373 * private mappings. 374 */ 375 h->resv_huge_pages--; 376 } 377} 378 379/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 380void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 381{ 382 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 383 if (!(vma->vm_flags & VM_MAYSHARE)) 384 vma->vm_private_data = (void *)0; 385} 386 387/* Returns true if the VMA has associated reserve pages */ 388static int vma_has_reserves(struct vm_area_struct *vma) 389{ 390 if (vma->vm_flags & VM_MAYSHARE) 391 return 1; 392 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 393 return 1; 394 return 0; 395} 396 397static void clear_gigantic_page(struct page *page, 398 unsigned long addr, unsigned long sz) 399{ 400 int i; 401 struct page *p = page; 402 403 might_sleep(); 404 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) { 405 cond_resched(); 406 clear_user_highpage(p, addr + i * PAGE_SIZE); 407 } 408} 409static void clear_huge_page(struct page *page, 410 unsigned long addr, unsigned long sz) 411{ 412 int i; 413 414 if (unlikely(sz/PAGE_SIZE > MAX_ORDER_NR_PAGES)) { 415 clear_gigantic_page(page, addr, sz); 416 return; 417 } 418 419 might_sleep(); 420 for (i = 0; i < sz/PAGE_SIZE; i++) { 421 cond_resched(); 422 clear_user_highpage(page + i, addr + i * PAGE_SIZE); 423 } 424} 425 426static void copy_user_gigantic_page(struct page *dst, struct page *src, 427 unsigned long addr, struct vm_area_struct *vma) 428{ 429 int i; 430 struct hstate *h = hstate_vma(vma); 431 struct page *dst_base = dst; 432 struct page *src_base = src; 433 434 for (i = 0; i < pages_per_huge_page(h); ) { 435 cond_resched(); 436 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 437 438 i++; 439 dst = mem_map_next(dst, dst_base, i); 440 src = mem_map_next(src, src_base, i); 441 } 442} 443 444static void copy_user_huge_page(struct page *dst, struct page *src, 445 unsigned long addr, struct vm_area_struct *vma) 446{ 447 int i; 448 struct hstate *h = hstate_vma(vma); 449 450 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 451 copy_user_gigantic_page(dst, src, addr, vma); 452 return; 453 } 454 455 might_sleep(); 456 for (i = 0; i < pages_per_huge_page(h); i++) { 457 cond_resched(); 458 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); 459 } 460} 461 462static void copy_gigantic_page(struct page *dst, struct page *src) 463{ 464 int i; 465 struct hstate *h = page_hstate(src); 466 struct page *dst_base = dst; 467 struct page *src_base = src; 468 469 for (i = 0; i < pages_per_huge_page(h); ) { 470 cond_resched(); 471 copy_highpage(dst, src); 472 473 i++; 474 dst = mem_map_next(dst, dst_base, i); 475 src = mem_map_next(src, src_base, i); 476 } 477} 478 479void copy_huge_page(struct page *dst, struct page *src) 480{ 481 int i; 482 struct hstate *h = page_hstate(src); 483 484 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 485 copy_gigantic_page(dst, src); 486 return; 487 } 488 489 might_sleep(); 490 for (i = 0; i < pages_per_huge_page(h); i++) { 491 cond_resched(); 492 copy_highpage(dst + i, src + i); 493 } 494} 495 496static void enqueue_huge_page(struct hstate *h, struct page *page) 497{ 498 int nid = page_to_nid(page); 499 list_add(&page->lru, &h->hugepage_freelists[nid]); 500 h->free_huge_pages++; 501 h->free_huge_pages_node[nid]++; 502} 503 504static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 505{ 506 struct page *page; 507 508 if (list_empty(&h->hugepage_freelists[nid])) 509 return NULL; 510 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); 511 list_del(&page->lru); 512 h->free_huge_pages--; 513 h->free_huge_pages_node[nid]--; 514 return page; 515} 516 517static struct page *dequeue_huge_page_vma(struct hstate *h, 518 struct vm_area_struct *vma, 519 unsigned long address, int avoid_reserve) 520{ 521 struct page *page = NULL; 522 struct mempolicy *mpol; 523 nodemask_t *nodemask; 524 struct zonelist *zonelist; 525 struct zone *zone; 526 struct zoneref *z; 527 528 get_mems_allowed(); 529 zonelist = huge_zonelist(vma, address, 530 htlb_alloc_mask, &mpol, &nodemask); 531 /* 532 * A child process with MAP_PRIVATE mappings created by their parent 533 * have no page reserves. This check ensures that reservations are 534 * not "stolen". The child may still get SIGKILLed 535 */ 536 if (!vma_has_reserves(vma) && 537 h->free_huge_pages - h->resv_huge_pages == 0) 538 goto err; 539 540 /* If reserves cannot be used, ensure enough pages are in the pool */ 541 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 542 goto err;; 543 544 for_each_zone_zonelist_nodemask(zone, z, zonelist, 545 MAX_NR_ZONES - 1, nodemask) { 546 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { 547 page = dequeue_huge_page_node(h, zone_to_nid(zone)); 548 if (page) { 549 if (!avoid_reserve) 550 decrement_hugepage_resv_vma(h, vma); 551 break; 552 } 553 } 554 } 555err: 556 mpol_cond_put(mpol); 557 put_mems_allowed(); 558 return page; 559} 560 561static void update_and_free_page(struct hstate *h, struct page *page) 562{ 563 int i; 564 565 VM_BUG_ON(h->order >= MAX_ORDER); 566 567 h->nr_huge_pages--; 568 h->nr_huge_pages_node[page_to_nid(page)]--; 569 for (i = 0; i < pages_per_huge_page(h); i++) { 570 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 571 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 572 1 << PG_private | 1<< PG_writeback); 573 } 574 set_compound_page_dtor(page, NULL); 575 set_page_refcounted(page); 576 arch_release_hugepage(page); 577 __free_pages(page, huge_page_order(h)); 578} 579 580struct hstate *size_to_hstate(unsigned long size) 581{ 582 struct hstate *h; 583 584 for_each_hstate(h) { 585 if (huge_page_size(h) == size) 586 return h; 587 } 588 return NULL; 589} 590 591static void free_huge_page(struct page *page) 592{ 593 /* 594 * Can't pass hstate in here because it is called from the 595 * compound page destructor. 596 */ 597 struct hstate *h = page_hstate(page); 598 int nid = page_to_nid(page); 599 struct address_space *mapping; 600 601 mapping = (struct address_space *) page_private(page); 602 set_page_private(page, 0); 603 page->mapping = NULL; 604 BUG_ON(page_count(page)); 605 BUG_ON(page_mapcount(page)); 606 INIT_LIST_HEAD(&page->lru); 607 608 spin_lock(&hugetlb_lock); 609 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 610 update_and_free_page(h, page); 611 h->surplus_huge_pages--; 612 h->surplus_huge_pages_node[nid]--; 613 } else { 614 enqueue_huge_page(h, page); 615 } 616 spin_unlock(&hugetlb_lock); 617 if (mapping) 618 hugetlb_put_quota(mapping, 1); 619} 620 621static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 622{ 623 set_compound_page_dtor(page, free_huge_page); 624 spin_lock(&hugetlb_lock); 625 h->nr_huge_pages++; 626 h->nr_huge_pages_node[nid]++; 627 spin_unlock(&hugetlb_lock); 628 put_page(page); /* free it into the hugepage allocator */ 629} 630 631static void prep_compound_gigantic_page(struct page *page, unsigned long order) 632{ 633 int i; 634 int nr_pages = 1 << order; 635 struct page *p = page + 1; 636 637 /* we rely on prep_new_huge_page to set the destructor */ 638 set_compound_order(page, order); 639 __SetPageHead(page); 640 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 641 __SetPageTail(p); 642 p->first_page = page; 643 } 644} 645 646int PageHuge(struct page *page) 647{ 648 compound_page_dtor *dtor; 649 650 if (!PageCompound(page)) 651 return 0; 652 653 page = compound_head(page); 654 dtor = get_compound_page_dtor(page); 655 656 return dtor == free_huge_page; 657} 658 659EXPORT_SYMBOL_GPL(PageHuge); 660 661static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 662{ 663 struct page *page; 664 665 if (h->order >= MAX_ORDER) 666 return NULL; 667 668 page = alloc_pages_exact_node(nid, 669 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 670 __GFP_REPEAT|__GFP_NOWARN, 671 huge_page_order(h)); 672 if (page) { 673 if (arch_prepare_hugepage(page)) { 674 __free_pages(page, huge_page_order(h)); 675 return NULL; 676 } 677 prep_new_huge_page(h, page, nid); 678 } 679 680 return page; 681} 682 683/* 684 * common helper functions for hstate_next_node_to_{alloc|free}. 685 * We may have allocated or freed a huge page based on a different 686 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 687 * be outside of *nodes_allowed. Ensure that we use an allowed 688 * node for alloc or free. 689 */ 690static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 691{ 692 nid = next_node(nid, *nodes_allowed); 693 if (nid == MAX_NUMNODES) 694 nid = first_node(*nodes_allowed); 695 VM_BUG_ON(nid >= MAX_NUMNODES); 696 697 return nid; 698} 699 700static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 701{ 702 if (!node_isset(nid, *nodes_allowed)) 703 nid = next_node_allowed(nid, nodes_allowed); 704 return nid; 705} 706 707/* 708 * returns the previously saved node ["this node"] from which to 709 * allocate a persistent huge page for the pool and advance the 710 * next node from which to allocate, handling wrap at end of node 711 * mask. 712 */ 713static int hstate_next_node_to_alloc(struct hstate *h, 714 nodemask_t *nodes_allowed) 715{ 716 int nid; 717 718 VM_BUG_ON(!nodes_allowed); 719 720 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 721 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 722 723 return nid; 724} 725 726static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 727{ 728 struct page *page; 729 int start_nid; 730 int next_nid; 731 int ret = 0; 732 733 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 734 next_nid = start_nid; 735 736 do { 737 page = alloc_fresh_huge_page_node(h, next_nid); 738 if (page) { 739 ret = 1; 740 break; 741 } 742 next_nid = hstate_next_node_to_alloc(h, nodes_allowed); 743 } while (next_nid != start_nid); 744 745 if (ret) 746 count_vm_event(HTLB_BUDDY_PGALLOC); 747 else 748 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 749 750 return ret; 751} 752 753/* 754 * helper for free_pool_huge_page() - return the previously saved 755 * node ["this node"] from which to free a huge page. Advance the 756 * next node id whether or not we find a free huge page to free so 757 * that the next attempt to free addresses the next node. 758 */ 759static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 760{ 761 int nid; 762 763 VM_BUG_ON(!nodes_allowed); 764 765 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 766 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 767 768 return nid; 769} 770 771/* 772 * Free huge page from pool from next node to free. 773 * Attempt to keep persistent huge pages more or less 774 * balanced over allowed nodes. 775 * Called with hugetlb_lock locked. 776 */ 777static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 778 bool acct_surplus) 779{ 780 int start_nid; 781 int next_nid; 782 int ret = 0; 783 784 start_nid = hstate_next_node_to_free(h, nodes_allowed); 785 next_nid = start_nid; 786 787 do { 788 /* 789 * If we're returning unused surplus pages, only examine 790 * nodes with surplus pages. 791 */ 792 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && 793 !list_empty(&h->hugepage_freelists[next_nid])) { 794 struct page *page = 795 list_entry(h->hugepage_freelists[next_nid].next, 796 struct page, lru); 797 list_del(&page->lru); 798 h->free_huge_pages--; 799 h->free_huge_pages_node[next_nid]--; 800 if (acct_surplus) { 801 h->surplus_huge_pages--; 802 h->surplus_huge_pages_node[next_nid]--; 803 } 804 update_and_free_page(h, page); 805 ret = 1; 806 break; 807 } 808 next_nid = hstate_next_node_to_free(h, nodes_allowed); 809 } while (next_nid != start_nid); 810 811 return ret; 812} 813 814static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) 815{ 816 struct page *page; 817 unsigned int r_nid; 818 819 if (h->order >= MAX_ORDER) 820 return NULL; 821 822 /* 823 * Assume we will successfully allocate the surplus page to 824 * prevent racing processes from causing the surplus to exceed 825 * overcommit 826 * 827 * This however introduces a different race, where a process B 828 * tries to grow the static hugepage pool while alloc_pages() is 829 * called by process A. B will only examine the per-node 830 * counters in determining if surplus huge pages can be 831 * converted to normal huge pages in adjust_pool_surplus(). A 832 * won't be able to increment the per-node counter, until the 833 * lock is dropped by B, but B doesn't drop hugetlb_lock until 834 * no more huge pages can be converted from surplus to normal 835 * state (and doesn't try to convert again). Thus, we have a 836 * case where a surplus huge page exists, the pool is grown, and 837 * the surplus huge page still exists after, even though it 838 * should just have been converted to a normal huge page. This 839 * does not leak memory, though, as the hugepage will be freed 840 * once it is out of use. It also does not allow the counters to 841 * go out of whack in adjust_pool_surplus() as we don't modify 842 * the node values until we've gotten the hugepage and only the 843 * per-node value is checked there. 844 */ 845 spin_lock(&hugetlb_lock); 846 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 847 spin_unlock(&hugetlb_lock); 848 return NULL; 849 } else { 850 h->nr_huge_pages++; 851 h->surplus_huge_pages++; 852 } 853 spin_unlock(&hugetlb_lock); 854 855 if (nid == NUMA_NO_NODE) 856 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 857 __GFP_REPEAT|__GFP_NOWARN, 858 huge_page_order(h)); 859 else 860 page = alloc_pages_exact_node(nid, 861 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 862 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); 863 864 if (page && arch_prepare_hugepage(page)) { 865 __free_pages(page, huge_page_order(h)); 866 return NULL; 867 } 868 869 spin_lock(&hugetlb_lock); 870 if (page) { 871 /* 872 * This page is now managed by the hugetlb allocator and has 873 * no users -- drop the buddy allocator's reference. 874 */ 875 put_page_testzero(page); 876 VM_BUG_ON(page_count(page)); 877 r_nid = page_to_nid(page); 878 set_compound_page_dtor(page, free_huge_page); 879 /* 880 * We incremented the global counters already 881 */ 882 h->nr_huge_pages_node[r_nid]++; 883 h->surplus_huge_pages_node[r_nid]++; 884 __count_vm_event(HTLB_BUDDY_PGALLOC); 885 } else { 886 h->nr_huge_pages--; 887 h->surplus_huge_pages--; 888 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 889 } 890 spin_unlock(&hugetlb_lock); 891 892 return page; 893} 894 895/* 896 * This allocation function is useful in the context where vma is irrelevant. 897 * E.g. soft-offlining uses this function because it only cares physical 898 * address of error page. 899 */ 900struct page *alloc_huge_page_node(struct hstate *h, int nid) 901{ 902 struct page *page; 903 904 spin_lock(&hugetlb_lock); 905 page = dequeue_huge_page_node(h, nid); 906 spin_unlock(&hugetlb_lock); 907 908 if (!page) 909 page = alloc_buddy_huge_page(h, nid); 910 911 return page; 912} 913 914/* 915 * Increase the hugetlb pool such that it can accomodate a reservation 916 * of size 'delta'. 917 */ 918static int gather_surplus_pages(struct hstate *h, int delta) 919{ 920 struct list_head surplus_list; 921 struct page *page, *tmp; 922 int ret, i; 923 int needed, allocated; 924 925 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 926 if (needed <= 0) { 927 h->resv_huge_pages += delta; 928 return 0; 929 } 930 931 allocated = 0; 932 INIT_LIST_HEAD(&surplus_list); 933 934 ret = -ENOMEM; 935retry: 936 spin_unlock(&hugetlb_lock); 937 for (i = 0; i < needed; i++) { 938 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 939 if (!page) { 940 /* 941 * We were not able to allocate enough pages to 942 * satisfy the entire reservation so we free what 943 * we've allocated so far. 944 */ 945 spin_lock(&hugetlb_lock); 946 needed = 0; 947 goto free; 948 } 949 950 list_add(&page->lru, &surplus_list); 951 } 952 allocated += needed; 953 954 /* 955 * After retaking hugetlb_lock, we need to recalculate 'needed' 956 * because either resv_huge_pages or free_huge_pages may have changed. 957 */ 958 spin_lock(&hugetlb_lock); 959 needed = (h->resv_huge_pages + delta) - 960 (h->free_huge_pages + allocated); 961 if (needed > 0) 962 goto retry; 963 964 /* 965 * The surplus_list now contains _at_least_ the number of extra pages 966 * needed to accomodate the reservation. Add the appropriate number 967 * of pages to the hugetlb pool and free the extras back to the buddy 968 * allocator. Commit the entire reservation here to prevent another 969 * process from stealing the pages as they are added to the pool but 970 * before they are reserved. 971 */ 972 needed += allocated; 973 h->resv_huge_pages += delta; 974 ret = 0; 975free: 976 /* Free the needed pages to the hugetlb pool */ 977 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 978 if ((--needed) < 0) 979 break; 980 list_del(&page->lru); 981 enqueue_huge_page(h, page); 982 } 983 984 /* Free unnecessary surplus pages to the buddy allocator */ 985 if (!list_empty(&surplus_list)) { 986 spin_unlock(&hugetlb_lock); 987 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 988 list_del(&page->lru); 989 /* 990 * The page has a reference count of zero already, so 991 * call free_huge_page directly instead of using 992 * put_page. This must be done with hugetlb_lock 993 * unlocked which is safe because free_huge_page takes 994 * hugetlb_lock before deciding how to free the page. 995 */ 996 free_huge_page(page); 997 } 998 spin_lock(&hugetlb_lock); 999 } 1000 1001 return ret; 1002} 1003 1004/* 1005 * When releasing a hugetlb pool reservation, any surplus pages that were 1006 * allocated to satisfy the reservation must be explicitly freed if they were 1007 * never used. 1008 * Called with hugetlb_lock held. 1009 */ 1010static void return_unused_surplus_pages(struct hstate *h, 1011 unsigned long unused_resv_pages) 1012{ 1013 unsigned long nr_pages; 1014 1015 /* Uncommit the reservation */ 1016 h->resv_huge_pages -= unused_resv_pages; 1017 1018 /* Cannot return gigantic pages currently */ 1019 if (h->order >= MAX_ORDER) 1020 return; 1021 1022 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 1023 1024 /* 1025 * We want to release as many surplus pages as possible, spread 1026 * evenly across all nodes with memory. Iterate across these nodes 1027 * until we can no longer free unreserved surplus pages. This occurs 1028 * when the nodes with surplus pages have no free pages. 1029 * free_pool_huge_page() will balance the the freed pages across the 1030 * on-line nodes with memory and will handle the hstate accounting. 1031 */ 1032 while (nr_pages--) { 1033 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1)) 1034 break; 1035 } 1036} 1037 1038/* 1039 * Determine if the huge page at addr within the vma has an associated 1040 * reservation. Where it does not we will need to logically increase 1041 * reservation and actually increase quota before an allocation can occur. 1042 * Where any new reservation would be required the reservation change is 1043 * prepared, but not committed. Once the page has been quota'd allocated 1044 * an instantiated the change should be committed via vma_commit_reservation. 1045 * No action is required on failure. 1046 */ 1047static long vma_needs_reservation(struct hstate *h, 1048 struct vm_area_struct *vma, unsigned long addr) 1049{ 1050 struct address_space *mapping = vma->vm_file->f_mapping; 1051 struct inode *inode = mapping->host; 1052 1053 if (vma->vm_flags & VM_MAYSHARE) { 1054 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1055 return region_chg(&inode->i_mapping->private_list, 1056 idx, idx + 1); 1057 1058 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1059 return 1; 1060 1061 } else { 1062 long err; 1063 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1064 struct resv_map *reservations = vma_resv_map(vma); 1065 1066 err = region_chg(&reservations->regions, idx, idx + 1); 1067 if (err < 0) 1068 return err; 1069 return 0; 1070 } 1071} 1072static void vma_commit_reservation(struct hstate *h, 1073 struct vm_area_struct *vma, unsigned long addr) 1074{ 1075 struct address_space *mapping = vma->vm_file->f_mapping; 1076 struct inode *inode = mapping->host; 1077 1078 if (vma->vm_flags & VM_MAYSHARE) { 1079 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1080 region_add(&inode->i_mapping->private_list, idx, idx + 1); 1081 1082 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1083 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1084 struct resv_map *reservations = vma_resv_map(vma); 1085 1086 /* Mark this page used in the map. */ 1087 region_add(&reservations->regions, idx, idx + 1); 1088 } 1089} 1090 1091static struct page *alloc_huge_page(struct vm_area_struct *vma, 1092 unsigned long addr, int avoid_reserve) 1093{ 1094 struct hstate *h = hstate_vma(vma); 1095 struct page *page; 1096 struct address_space *mapping = vma->vm_file->f_mapping; 1097 struct inode *inode = mapping->host; 1098 long chg; 1099 1100 /* 1101 * Processes that did not create the mapping will have no reserves and 1102 * will not have accounted against quota. Check that the quota can be 1103 * made before satisfying the allocation 1104 * MAP_NORESERVE mappings may also need pages and quota allocated 1105 * if no reserve mapping overlaps. 1106 */ 1107 chg = vma_needs_reservation(h, vma, addr); 1108 if (chg < 0) 1109 return ERR_PTR(chg); 1110 if (chg) 1111 if (hugetlb_get_quota(inode->i_mapping, chg)) 1112 return ERR_PTR(-ENOSPC); 1113 1114 spin_lock(&hugetlb_lock); 1115 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 1116 spin_unlock(&hugetlb_lock); 1117 1118 if (!page) { 1119 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1120 if (!page) { 1121 hugetlb_put_quota(inode->i_mapping, chg); 1122 return ERR_PTR(-VM_FAULT_SIGBUS); 1123 } 1124 } 1125 1126 set_page_refcounted(page); 1127 set_page_private(page, (unsigned long) mapping); 1128 1129 vma_commit_reservation(h, vma, addr); 1130 1131 return page; 1132} 1133 1134int __weak alloc_bootmem_huge_page(struct hstate *h) 1135{ 1136 struct huge_bootmem_page *m; 1137 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]); 1138 1139 while (nr_nodes) { 1140 void *addr; 1141 1142 addr = __alloc_bootmem_node_nopanic( 1143 NODE_DATA(hstate_next_node_to_alloc(h, 1144 &node_states[N_HIGH_MEMORY])), 1145 huge_page_size(h), huge_page_size(h), 0); 1146 1147 if (addr) { 1148 /* 1149 * Use the beginning of the huge page to store the 1150 * huge_bootmem_page struct (until gather_bootmem 1151 * puts them into the mem_map). 1152 */ 1153 m = addr; 1154 goto found; 1155 } 1156 nr_nodes--; 1157 } 1158 return 0; 1159 1160found: 1161 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1162 /* Put them into a private list first because mem_map is not up yet */ 1163 list_add(&m->list, &huge_boot_pages); 1164 m->hstate = h; 1165 return 1; 1166} 1167 1168static void prep_compound_huge_page(struct page *page, int order) 1169{ 1170 if (unlikely(order > (MAX_ORDER - 1))) 1171 prep_compound_gigantic_page(page, order); 1172 else 1173 prep_compound_page(page, order); 1174} 1175 1176/* Put bootmem huge pages into the standard lists after mem_map is up */ 1177static void __init gather_bootmem_prealloc(void) 1178{ 1179 struct huge_bootmem_page *m; 1180 1181 list_for_each_entry(m, &huge_boot_pages, list) { 1182 struct page *page = virt_to_page(m); 1183 struct hstate *h = m->hstate; 1184 __ClearPageReserved(page); 1185 WARN_ON(page_count(page) != 1); 1186 prep_compound_huge_page(page, h->order); 1187 prep_new_huge_page(h, page, page_to_nid(page)); 1188 } 1189} 1190 1191static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1192{ 1193 unsigned long i; 1194 1195 for (i = 0; i < h->max_huge_pages; ++i) { 1196 if (h->order >= MAX_ORDER) { 1197 if (!alloc_bootmem_huge_page(h)) 1198 break; 1199 } else if (!alloc_fresh_huge_page(h, 1200 &node_states[N_HIGH_MEMORY])) 1201 break; 1202 } 1203 h->max_huge_pages = i; 1204} 1205 1206static void __init hugetlb_init_hstates(void) 1207{ 1208 struct hstate *h; 1209 1210 for_each_hstate(h) { 1211 /* oversize hugepages were init'ed in early boot */ 1212 if (h->order < MAX_ORDER) 1213 hugetlb_hstate_alloc_pages(h); 1214 } 1215} 1216 1217static char * __init memfmt(char *buf, unsigned long n) 1218{ 1219 if (n >= (1UL << 30)) 1220 sprintf(buf, "%lu GB", n >> 30); 1221 else if (n >= (1UL << 20)) 1222 sprintf(buf, "%lu MB", n >> 20); 1223 else 1224 sprintf(buf, "%lu KB", n >> 10); 1225 return buf; 1226} 1227 1228static void __init report_hugepages(void) 1229{ 1230 struct hstate *h; 1231 1232 for_each_hstate(h) { 1233 char buf[32]; 1234 printk(KERN_INFO "HugeTLB registered %s page size, " 1235 "pre-allocated %ld pages\n", 1236 memfmt(buf, huge_page_size(h)), 1237 h->free_huge_pages); 1238 } 1239} 1240 1241#ifdef CONFIG_HIGHMEM 1242static void try_to_free_low(struct hstate *h, unsigned long count, 1243 nodemask_t *nodes_allowed) 1244{ 1245 int i; 1246 1247 if (h->order >= MAX_ORDER) 1248 return; 1249 1250 for_each_node_mask(i, *nodes_allowed) { 1251 struct page *page, *next; 1252 struct list_head *freel = &h->hugepage_freelists[i]; 1253 list_for_each_entry_safe(page, next, freel, lru) { 1254 if (count >= h->nr_huge_pages) 1255 return; 1256 if (PageHighMem(page)) 1257 continue; 1258 list_del(&page->lru); 1259 update_and_free_page(h, page); 1260 h->free_huge_pages--; 1261 h->free_huge_pages_node[page_to_nid(page)]--; 1262 } 1263 } 1264} 1265#else 1266static inline void try_to_free_low(struct hstate *h, unsigned long count, 1267 nodemask_t *nodes_allowed) 1268{ 1269} 1270#endif 1271 1272/* 1273 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1274 * balanced by operating on them in a round-robin fashion. 1275 * Returns 1 if an adjustment was made. 1276 */ 1277static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1278 int delta) 1279{ 1280 int start_nid, next_nid; 1281 int ret = 0; 1282 1283 VM_BUG_ON(delta != -1 && delta != 1); 1284 1285 if (delta < 0) 1286 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 1287 else 1288 start_nid = hstate_next_node_to_free(h, nodes_allowed); 1289 next_nid = start_nid; 1290 1291 do { 1292 int nid = next_nid; 1293 if (delta < 0) { 1294 /* 1295 * To shrink on this node, there must be a surplus page 1296 */ 1297 if (!h->surplus_huge_pages_node[nid]) { 1298 next_nid = hstate_next_node_to_alloc(h, 1299 nodes_allowed); 1300 continue; 1301 } 1302 } 1303 if (delta > 0) { 1304 /* 1305 * Surplus cannot exceed the total number of pages 1306 */ 1307 if (h->surplus_huge_pages_node[nid] >= 1308 h->nr_huge_pages_node[nid]) { 1309 next_nid = hstate_next_node_to_free(h, 1310 nodes_allowed); 1311 continue; 1312 } 1313 } 1314 1315 h->surplus_huge_pages += delta; 1316 h->surplus_huge_pages_node[nid] += delta; 1317 ret = 1; 1318 break; 1319 } while (next_nid != start_nid); 1320 1321 return ret; 1322} 1323 1324#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1325static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1326 nodemask_t *nodes_allowed) 1327{ 1328 unsigned long min_count, ret; 1329 1330 if (h->order >= MAX_ORDER) 1331 return h->max_huge_pages; 1332 1333 /* 1334 * Increase the pool size 1335 * First take pages out of surplus state. Then make up the 1336 * remaining difference by allocating fresh huge pages. 1337 * 1338 * We might race with alloc_buddy_huge_page() here and be unable 1339 * to convert a surplus huge page to a normal huge page. That is 1340 * not critical, though, it just means the overall size of the 1341 * pool might be one hugepage larger than it needs to be, but 1342 * within all the constraints specified by the sysctls. 1343 */ 1344 spin_lock(&hugetlb_lock); 1345 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1346 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1347 break; 1348 } 1349 1350 while (count > persistent_huge_pages(h)) { 1351 /* 1352 * If this allocation races such that we no longer need the 1353 * page, free_huge_page will handle it by freeing the page 1354 * and reducing the surplus. 1355 */ 1356 spin_unlock(&hugetlb_lock); 1357 ret = alloc_fresh_huge_page(h, nodes_allowed); 1358 spin_lock(&hugetlb_lock); 1359 if (!ret) 1360 goto out; 1361 1362 /* Bail for signals. Probably ctrl-c from user */ 1363 if (signal_pending(current)) 1364 goto out; 1365 } 1366 1367 /* 1368 * Decrease the pool size 1369 * First return free pages to the buddy allocator (being careful 1370 * to keep enough around to satisfy reservations). Then place 1371 * pages into surplus state as needed so the pool will shrink 1372 * to the desired size as pages become free. 1373 * 1374 * By placing pages into the surplus state independent of the 1375 * overcommit value, we are allowing the surplus pool size to 1376 * exceed overcommit. There are few sane options here. Since 1377 * alloc_buddy_huge_page() is checking the global counter, 1378 * though, we'll note that we're not allowed to exceed surplus 1379 * and won't grow the pool anywhere else. Not until one of the 1380 * sysctls are changed, or the surplus pages go out of use. 1381 */ 1382 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1383 min_count = max(count, min_count); 1384 try_to_free_low(h, min_count, nodes_allowed); 1385 while (min_count < persistent_huge_pages(h)) { 1386 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1387 break; 1388 } 1389 while (count < persistent_huge_pages(h)) { 1390 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1391 break; 1392 } 1393out: 1394 ret = persistent_huge_pages(h); 1395 spin_unlock(&hugetlb_lock); 1396 return ret; 1397} 1398 1399#define HSTATE_ATTR_RO(_name) \ 1400 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1401 1402#define HSTATE_ATTR(_name) \ 1403 static struct kobj_attribute _name##_attr = \ 1404 __ATTR(_name, 0644, _name##_show, _name##_store) 1405 1406static struct kobject *hugepages_kobj; 1407static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1408 1409static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1410 1411static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1412{ 1413 int i; 1414 1415 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1416 if (hstate_kobjs[i] == kobj) { 1417 if (nidp) 1418 *nidp = NUMA_NO_NODE; 1419 return &hstates[i]; 1420 } 1421 1422 return kobj_to_node_hstate(kobj, nidp); 1423} 1424 1425static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1426 struct kobj_attribute *attr, char *buf) 1427{ 1428 struct hstate *h; 1429 unsigned long nr_huge_pages; 1430 int nid; 1431 1432 h = kobj_to_hstate(kobj, &nid); 1433 if (nid == NUMA_NO_NODE) 1434 nr_huge_pages = h->nr_huge_pages; 1435 else 1436 nr_huge_pages = h->nr_huge_pages_node[nid]; 1437 1438 return sprintf(buf, "%lu\n", nr_huge_pages); 1439} 1440static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1441 struct kobject *kobj, struct kobj_attribute *attr, 1442 const char *buf, size_t len) 1443{ 1444 int err; 1445 int nid; 1446 unsigned long count; 1447 struct hstate *h; 1448 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1449 1450 err = strict_strtoul(buf, 10, &count); 1451 if (err) 1452 return 0; 1453 1454 h = kobj_to_hstate(kobj, &nid); 1455 if (nid == NUMA_NO_NODE) { 1456 /* 1457 * global hstate attribute 1458 */ 1459 if (!(obey_mempolicy && 1460 init_nodemask_of_mempolicy(nodes_allowed))) { 1461 NODEMASK_FREE(nodes_allowed); 1462 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1463 } 1464 } else if (nodes_allowed) { 1465 /* 1466 * per node hstate attribute: adjust count to global, 1467 * but restrict alloc/free to the specified node. 1468 */ 1469 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1470 init_nodemask_of_node(nodes_allowed, nid); 1471 } else 1472 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1473 1474 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1475 1476 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1477 NODEMASK_FREE(nodes_allowed); 1478 1479 return len; 1480} 1481 1482static ssize_t nr_hugepages_show(struct kobject *kobj, 1483 struct kobj_attribute *attr, char *buf) 1484{ 1485 return nr_hugepages_show_common(kobj, attr, buf); 1486} 1487 1488static ssize_t nr_hugepages_store(struct kobject *kobj, 1489 struct kobj_attribute *attr, const char *buf, size_t len) 1490{ 1491 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1492} 1493HSTATE_ATTR(nr_hugepages); 1494 1495#ifdef CONFIG_NUMA 1496 1497/* 1498 * hstate attribute for optionally mempolicy-based constraint on persistent 1499 * huge page alloc/free. 1500 */ 1501static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1502 struct kobj_attribute *attr, char *buf) 1503{ 1504 return nr_hugepages_show_common(kobj, attr, buf); 1505} 1506 1507static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1508 struct kobj_attribute *attr, const char *buf, size_t len) 1509{ 1510 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1511} 1512HSTATE_ATTR(nr_hugepages_mempolicy); 1513#endif 1514 1515 1516static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1517 struct kobj_attribute *attr, char *buf) 1518{ 1519 struct hstate *h = kobj_to_hstate(kobj, NULL); 1520 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1521} 1522static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1523 struct kobj_attribute *attr, const char *buf, size_t count) 1524{ 1525 int err; 1526 unsigned long input; 1527 struct hstate *h = kobj_to_hstate(kobj, NULL); 1528 1529 err = strict_strtoul(buf, 10, &input); 1530 if (err) 1531 return 0; 1532 1533 spin_lock(&hugetlb_lock); 1534 h->nr_overcommit_huge_pages = input; 1535 spin_unlock(&hugetlb_lock); 1536 1537 return count; 1538} 1539HSTATE_ATTR(nr_overcommit_hugepages); 1540 1541static ssize_t free_hugepages_show(struct kobject *kobj, 1542 struct kobj_attribute *attr, char *buf) 1543{ 1544 struct hstate *h; 1545 unsigned long free_huge_pages; 1546 int nid; 1547 1548 h = kobj_to_hstate(kobj, &nid); 1549 if (nid == NUMA_NO_NODE) 1550 free_huge_pages = h->free_huge_pages; 1551 else 1552 free_huge_pages = h->free_huge_pages_node[nid]; 1553 1554 return sprintf(buf, "%lu\n", free_huge_pages); 1555} 1556HSTATE_ATTR_RO(free_hugepages); 1557 1558static ssize_t resv_hugepages_show(struct kobject *kobj, 1559 struct kobj_attribute *attr, char *buf) 1560{ 1561 struct hstate *h = kobj_to_hstate(kobj, NULL); 1562 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1563} 1564HSTATE_ATTR_RO(resv_hugepages); 1565 1566static ssize_t surplus_hugepages_show(struct kobject *kobj, 1567 struct kobj_attribute *attr, char *buf) 1568{ 1569 struct hstate *h; 1570 unsigned long surplus_huge_pages; 1571 int nid; 1572 1573 h = kobj_to_hstate(kobj, &nid); 1574 if (nid == NUMA_NO_NODE) 1575 surplus_huge_pages = h->surplus_huge_pages; 1576 else 1577 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1578 1579 return sprintf(buf, "%lu\n", surplus_huge_pages); 1580} 1581HSTATE_ATTR_RO(surplus_hugepages); 1582 1583static struct attribute *hstate_attrs[] = { 1584 &nr_hugepages_attr.attr, 1585 &nr_overcommit_hugepages_attr.attr, 1586 &free_hugepages_attr.attr, 1587 &resv_hugepages_attr.attr, 1588 &surplus_hugepages_attr.attr, 1589#ifdef CONFIG_NUMA 1590 &nr_hugepages_mempolicy_attr.attr, 1591#endif 1592 NULL, 1593}; 1594 1595static struct attribute_group hstate_attr_group = { 1596 .attrs = hstate_attrs, 1597}; 1598 1599static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, 1600 struct kobject **hstate_kobjs, 1601 struct attribute_group *hstate_attr_group) 1602{ 1603 int retval; 1604 int hi = h - hstates; 1605 1606 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1607 if (!hstate_kobjs[hi]) 1608 return -ENOMEM; 1609 1610 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1611 if (retval) 1612 kobject_put(hstate_kobjs[hi]); 1613 1614 return retval; 1615} 1616 1617static void __init hugetlb_sysfs_init(void) 1618{ 1619 struct hstate *h; 1620 int err; 1621 1622 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1623 if (!hugepages_kobj) 1624 return; 1625 1626 for_each_hstate(h) { 1627 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1628 hstate_kobjs, &hstate_attr_group); 1629 if (err) 1630 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1631 h->name); 1632 } 1633} 1634 1635#ifdef CONFIG_NUMA 1636 1637/* 1638 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1639 * with node sysdevs in node_devices[] using a parallel array. The array 1640 * index of a node sysdev or _hstate == node id. 1641 * This is here to avoid any static dependency of the node sysdev driver, in 1642 * the base kernel, on the hugetlb module. 1643 */ 1644struct node_hstate { 1645 struct kobject *hugepages_kobj; 1646 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1647}; 1648struct node_hstate node_hstates[MAX_NUMNODES]; 1649 1650/* 1651 * A subset of global hstate attributes for node sysdevs 1652 */ 1653static struct attribute *per_node_hstate_attrs[] = { 1654 &nr_hugepages_attr.attr, 1655 &free_hugepages_attr.attr, 1656 &surplus_hugepages_attr.attr, 1657 NULL, 1658}; 1659 1660static struct attribute_group per_node_hstate_attr_group = { 1661 .attrs = per_node_hstate_attrs, 1662}; 1663 1664/* 1665 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj. 1666 * Returns node id via non-NULL nidp. 1667 */ 1668static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1669{ 1670 int nid; 1671 1672 for (nid = 0; nid < nr_node_ids; nid++) { 1673 struct node_hstate *nhs = &node_hstates[nid]; 1674 int i; 1675 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1676 if (nhs->hstate_kobjs[i] == kobj) { 1677 if (nidp) 1678 *nidp = nid; 1679 return &hstates[i]; 1680 } 1681 } 1682 1683 BUG(); 1684 return NULL; 1685} 1686 1687/* 1688 * Unregister hstate attributes from a single node sysdev. 1689 * No-op if no hstate attributes attached. 1690 */ 1691void hugetlb_unregister_node(struct node *node) 1692{ 1693 struct hstate *h; 1694 struct node_hstate *nhs = &node_hstates[node->sysdev.id]; 1695 1696 if (!nhs->hugepages_kobj) 1697 return; /* no hstate attributes */ 1698 1699 for_each_hstate(h) 1700 if (nhs->hstate_kobjs[h - hstates]) { 1701 kobject_put(nhs->hstate_kobjs[h - hstates]); 1702 nhs->hstate_kobjs[h - hstates] = NULL; 1703 } 1704 1705 kobject_put(nhs->hugepages_kobj); 1706 nhs->hugepages_kobj = NULL; 1707} 1708 1709/* 1710 * hugetlb module exit: unregister hstate attributes from node sysdevs 1711 * that have them. 1712 */ 1713static void hugetlb_unregister_all_nodes(void) 1714{ 1715 int nid; 1716 1717 /* 1718 * disable node sysdev registrations. 1719 */ 1720 register_hugetlbfs_with_node(NULL, NULL); 1721 1722 /* 1723 * remove hstate attributes from any nodes that have them. 1724 */ 1725 for (nid = 0; nid < nr_node_ids; nid++) 1726 hugetlb_unregister_node(&node_devices[nid]); 1727} 1728 1729/* 1730 * Register hstate attributes for a single node sysdev. 1731 * No-op if attributes already registered. 1732 */ 1733void hugetlb_register_node(struct node *node) 1734{ 1735 struct hstate *h; 1736 struct node_hstate *nhs = &node_hstates[node->sysdev.id]; 1737 int err; 1738 1739 if (nhs->hugepages_kobj) 1740 return; /* already allocated */ 1741 1742 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1743 &node->sysdev.kobj); 1744 if (!nhs->hugepages_kobj) 1745 return; 1746 1747 for_each_hstate(h) { 1748 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1749 nhs->hstate_kobjs, 1750 &per_node_hstate_attr_group); 1751 if (err) { 1752 printk(KERN_ERR "Hugetlb: Unable to add hstate %s" 1753 " for node %d\n", 1754 h->name, node->sysdev.id); 1755 hugetlb_unregister_node(node); 1756 break; 1757 } 1758 } 1759} 1760 1761/* 1762 * hugetlb init time: register hstate attributes for all registered node 1763 * sysdevs of nodes that have memory. All on-line nodes should have 1764 * registered their associated sysdev by this time. 1765 */ 1766static void hugetlb_register_all_nodes(void) 1767{ 1768 int nid; 1769 1770 for_each_node_state(nid, N_HIGH_MEMORY) { 1771 struct node *node = &node_devices[nid]; 1772 if (node->sysdev.id == nid) 1773 hugetlb_register_node(node); 1774 } 1775 1776 /* 1777 * Let the node sysdev driver know we're here so it can 1778 * [un]register hstate attributes on node hotplug. 1779 */ 1780 register_hugetlbfs_with_node(hugetlb_register_node, 1781 hugetlb_unregister_node); 1782} 1783#else /* !CONFIG_NUMA */ 1784 1785static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1786{ 1787 BUG(); 1788 if (nidp) 1789 *nidp = -1; 1790 return NULL; 1791} 1792 1793static void hugetlb_unregister_all_nodes(void) { } 1794 1795static void hugetlb_register_all_nodes(void) { } 1796 1797#endif 1798 1799static void __exit hugetlb_exit(void) 1800{ 1801 struct hstate *h; 1802 1803 hugetlb_unregister_all_nodes(); 1804 1805 for_each_hstate(h) { 1806 kobject_put(hstate_kobjs[h - hstates]); 1807 } 1808 1809 kobject_put(hugepages_kobj); 1810} 1811module_exit(hugetlb_exit); 1812 1813static int __init hugetlb_init(void) 1814{ 1815 /* Some platform decide whether they support huge pages at boot 1816 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1817 * there is no such support 1818 */ 1819 if (HPAGE_SHIFT == 0) 1820 return 0; 1821 1822 if (!size_to_hstate(default_hstate_size)) { 1823 default_hstate_size = HPAGE_SIZE; 1824 if (!size_to_hstate(default_hstate_size)) 1825 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1826 } 1827 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; 1828 if (default_hstate_max_huge_pages) 1829 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1830 1831 hugetlb_init_hstates(); 1832 1833 gather_bootmem_prealloc(); 1834 1835 report_hugepages(); 1836 1837 hugetlb_sysfs_init(); 1838 1839 hugetlb_register_all_nodes(); 1840 1841 return 0; 1842} 1843module_init(hugetlb_init); 1844 1845/* Should be called on processing a hugepagesz=... option */ 1846void __init hugetlb_add_hstate(unsigned order) 1847{ 1848 struct hstate *h; 1849 unsigned long i; 1850 1851 if (size_to_hstate(PAGE_SIZE << order)) { 1852 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1853 return; 1854 } 1855 BUG_ON(max_hstate >= HUGE_MAX_HSTATE); 1856 BUG_ON(order == 0); 1857 h = &hstates[max_hstate++]; 1858 h->order = order; 1859 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1860 h->nr_huge_pages = 0; 1861 h->free_huge_pages = 0; 1862 for (i = 0; i < MAX_NUMNODES; ++i) 1863 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1864 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]); 1865 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]); 1866 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1867 huge_page_size(h)/1024); 1868 1869 parsed_hstate = h; 1870} 1871 1872static int __init hugetlb_nrpages_setup(char *s) 1873{ 1874 unsigned long *mhp; 1875 static unsigned long *last_mhp; 1876 1877 /* 1878 * !max_hstate means we haven't parsed a hugepagesz= parameter yet, 1879 * so this hugepages= parameter goes to the "default hstate". 1880 */ 1881 if (!max_hstate) 1882 mhp = &default_hstate_max_huge_pages; 1883 else 1884 mhp = &parsed_hstate->max_huge_pages; 1885 1886 if (mhp == last_mhp) { 1887 printk(KERN_WARNING "hugepages= specified twice without " 1888 "interleaving hugepagesz=, ignoring\n"); 1889 return 1; 1890 } 1891 1892 if (sscanf(s, "%lu", mhp) <= 0) 1893 *mhp = 0; 1894 1895 /* 1896 * Global state is always initialized later in hugetlb_init. 1897 * But we need to allocate >= MAX_ORDER hstates here early to still 1898 * use the bootmem allocator. 1899 */ 1900 if (max_hstate && parsed_hstate->order >= MAX_ORDER) 1901 hugetlb_hstate_alloc_pages(parsed_hstate); 1902 1903 last_mhp = mhp; 1904 1905 return 1; 1906} 1907__setup("hugepages=", hugetlb_nrpages_setup); 1908 1909static int __init hugetlb_default_setup(char *s) 1910{ 1911 default_hstate_size = memparse(s, &s); 1912 return 1; 1913} 1914__setup("default_hugepagesz=", hugetlb_default_setup); 1915 1916static unsigned int cpuset_mems_nr(unsigned int *array) 1917{ 1918 int node; 1919 unsigned int nr = 0; 1920 1921 for_each_node_mask(node, cpuset_current_mems_allowed) 1922 nr += array[node]; 1923 1924 return nr; 1925} 1926 1927#ifdef CONFIG_SYSCTL 1928static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 1929 struct ctl_table *table, int write, 1930 void __user *buffer, size_t *length, loff_t *ppos) 1931{ 1932 struct hstate *h = &default_hstate; 1933 unsigned long tmp; 1934 1935 if (!write) 1936 tmp = h->max_huge_pages; 1937 1938 table->data = &tmp; 1939 table->maxlen = sizeof(unsigned long); 1940 proc_doulongvec_minmax(table, write, buffer, length, ppos); 1941 1942 if (write) { 1943 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 1944 GFP_KERNEL | __GFP_NORETRY); 1945 if (!(obey_mempolicy && 1946 init_nodemask_of_mempolicy(nodes_allowed))) { 1947 NODEMASK_FREE(nodes_allowed); 1948 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1949 } 1950 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 1951 1952 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1953 NODEMASK_FREE(nodes_allowed); 1954 } 1955 1956 return 0; 1957} 1958 1959int hugetlb_sysctl_handler(struct ctl_table *table, int write, 1960 void __user *buffer, size_t *length, loff_t *ppos) 1961{ 1962 1963 return hugetlb_sysctl_handler_common(false, table, write, 1964 buffer, length, ppos); 1965} 1966 1967#ifdef CONFIG_NUMA 1968int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 1969 void __user *buffer, size_t *length, loff_t *ppos) 1970{ 1971 return hugetlb_sysctl_handler_common(true, table, write, 1972 buffer, length, ppos); 1973} 1974#endif /* CONFIG_NUMA */ 1975 1976int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 1977 void __user *buffer, 1978 size_t *length, loff_t *ppos) 1979{ 1980 proc_dointvec(table, write, buffer, length, ppos); 1981 if (hugepages_treat_as_movable) 1982 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 1983 else 1984 htlb_alloc_mask = GFP_HIGHUSER; 1985 return 0; 1986} 1987 1988int hugetlb_overcommit_handler(struct ctl_table *table, int write, 1989 void __user *buffer, 1990 size_t *length, loff_t *ppos) 1991{ 1992 struct hstate *h = &default_hstate; 1993 unsigned long tmp; 1994 1995 if (!write) 1996 tmp = h->nr_overcommit_huge_pages; 1997 1998 table->data = &tmp; 1999 table->maxlen = sizeof(unsigned long); 2000 proc_doulongvec_minmax(table, write, buffer, length, ppos); 2001 2002 if (write) { 2003 spin_lock(&hugetlb_lock); 2004 h->nr_overcommit_huge_pages = tmp; 2005 spin_unlock(&hugetlb_lock); 2006 } 2007 2008 return 0; 2009} 2010 2011#endif /* CONFIG_SYSCTL */ 2012 2013void hugetlb_report_meminfo(struct seq_file *m) 2014{ 2015 struct hstate *h = &default_hstate; 2016 seq_printf(m, 2017 "HugePages_Total: %5lu\n" 2018 "HugePages_Free: %5lu\n" 2019 "HugePages_Rsvd: %5lu\n" 2020 "HugePages_Surp: %5lu\n" 2021 "Hugepagesize: %8lu kB\n", 2022 h->nr_huge_pages, 2023 h->free_huge_pages, 2024 h->resv_huge_pages, 2025 h->surplus_huge_pages, 2026 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2027} 2028 2029int hugetlb_report_node_meminfo(int nid, char *buf) 2030{ 2031 struct hstate *h = &default_hstate; 2032 return sprintf(buf, 2033 "Node %d HugePages_Total: %5u\n" 2034 "Node %d HugePages_Free: %5u\n" 2035 "Node %d HugePages_Surp: %5u\n", 2036 nid, h->nr_huge_pages_node[nid], 2037 nid, h->free_huge_pages_node[nid], 2038 nid, h->surplus_huge_pages_node[nid]); 2039} 2040 2041/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 2042unsigned long hugetlb_total_pages(void) 2043{ 2044 struct hstate *h = &default_hstate; 2045 return h->nr_huge_pages * pages_per_huge_page(h); 2046} 2047 2048static int hugetlb_acct_memory(struct hstate *h, long delta) 2049{ 2050 int ret = -ENOMEM; 2051 2052 spin_lock(&hugetlb_lock); 2053 /* 2054 * When cpuset is configured, it breaks the strict hugetlb page 2055 * reservation as the accounting is done on a global variable. Such 2056 * reservation is completely rubbish in the presence of cpuset because 2057 * the reservation is not checked against page availability for the 2058 * current cpuset. Application can still potentially OOM'ed by kernel 2059 * with lack of free htlb page in cpuset that the task is in. 2060 * Attempt to enforce strict accounting with cpuset is almost 2061 * impossible (or too ugly) because cpuset is too fluid that 2062 * task or memory node can be dynamically moved between cpusets. 2063 * 2064 * The change of semantics for shared hugetlb mapping with cpuset is 2065 * undesirable. However, in order to preserve some of the semantics, 2066 * we fall back to check against current free page availability as 2067 * a best attempt and hopefully to minimize the impact of changing 2068 * semantics that cpuset has. 2069 */ 2070 if (delta > 0) { 2071 if (gather_surplus_pages(h, delta) < 0) 2072 goto out; 2073 2074 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 2075 return_unused_surplus_pages(h, delta); 2076 goto out; 2077 } 2078 } 2079 2080 ret = 0; 2081 if (delta < 0) 2082 return_unused_surplus_pages(h, (unsigned long) -delta); 2083 2084out: 2085 spin_unlock(&hugetlb_lock); 2086 return ret; 2087} 2088 2089static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2090{ 2091 struct resv_map *reservations = vma_resv_map(vma); 2092 2093 /* 2094 * This new VMA should share its siblings reservation map if present. 2095 * The VMA will only ever have a valid reservation map pointer where 2096 * it is being copied for another still existing VMA. As that VMA 2097 * has a reference to the reservation map it cannot dissappear until 2098 * after this open call completes. It is therefore safe to take a 2099 * new reference here without additional locking. 2100 */ 2101 if (reservations) 2102 kref_get(&reservations->refs); 2103} 2104 2105static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2106{ 2107 struct hstate *h = hstate_vma(vma); 2108 struct resv_map *reservations = vma_resv_map(vma); 2109 unsigned long reserve; 2110 unsigned long start; 2111 unsigned long end; 2112 2113 if (reservations) { 2114 start = vma_hugecache_offset(h, vma, vma->vm_start); 2115 end = vma_hugecache_offset(h, vma, vma->vm_end); 2116 2117 reserve = (end - start) - 2118 region_count(&reservations->regions, start, end); 2119 2120 kref_put(&reservations->refs, resv_map_release); 2121 2122 if (reserve) { 2123 hugetlb_acct_memory(h, -reserve); 2124 hugetlb_put_quota(vma->vm_file->f_mapping, reserve); 2125 } 2126 } 2127} 2128 2129/* 2130 * We cannot handle pagefaults against hugetlb pages at all. They cause 2131 * handle_mm_fault() to try to instantiate regular-sized pages in the 2132 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2133 * this far. 2134 */ 2135static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2136{ 2137 BUG(); 2138 return 0; 2139} 2140 2141const struct vm_operations_struct hugetlb_vm_ops = { 2142 .fault = hugetlb_vm_op_fault, 2143 .open = hugetlb_vm_op_open, 2144 .close = hugetlb_vm_op_close, 2145}; 2146 2147static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2148 int writable) 2149{ 2150 pte_t entry; 2151 2152 if (writable) { 2153 entry = 2154 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 2155 } else { 2156 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 2157 } 2158 entry = pte_mkyoung(entry); 2159 entry = pte_mkhuge(entry); 2160 2161 return entry; 2162} 2163 2164static void set_huge_ptep_writable(struct vm_area_struct *vma, 2165 unsigned long address, pte_t *ptep) 2166{ 2167 pte_t entry; 2168 2169 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 2170 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { 2171 update_mmu_cache(vma, address, ptep); 2172 } 2173} 2174 2175 2176int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2177 struct vm_area_struct *vma) 2178{ 2179 pte_t *src_pte, *dst_pte, entry; 2180 struct page *ptepage; 2181 unsigned long addr; 2182 int cow; 2183 struct hstate *h = hstate_vma(vma); 2184 unsigned long sz = huge_page_size(h); 2185 2186 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2187 2188 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2189 src_pte = huge_pte_offset(src, addr); 2190 if (!src_pte) 2191 continue; 2192 dst_pte = huge_pte_alloc(dst, addr, sz); 2193 if (!dst_pte) 2194 goto nomem; 2195 2196 /* If the pagetables are shared don't copy or take references */ 2197 if (dst_pte == src_pte) 2198 continue; 2199 2200 spin_lock(&dst->page_table_lock); 2201 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 2202 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2203 if (cow) 2204 huge_ptep_set_wrprotect(src, addr, src_pte); 2205 entry = huge_ptep_get(src_pte); 2206 ptepage = pte_page(entry); 2207 get_page(ptepage); 2208 page_dup_rmap(ptepage); 2209 set_huge_pte_at(dst, addr, dst_pte, entry); 2210 } 2211 spin_unlock(&src->page_table_lock); 2212 spin_unlock(&dst->page_table_lock); 2213 } 2214 return 0; 2215 2216nomem: 2217 return -ENOMEM; 2218} 2219 2220static int is_hugetlb_entry_migration(pte_t pte) 2221{ 2222 swp_entry_t swp; 2223 2224 if (huge_pte_none(pte) || pte_present(pte)) 2225 return 0; 2226 swp = pte_to_swp_entry(pte); 2227 if (non_swap_entry(swp) && is_migration_entry(swp)) { 2228 return 1; 2229 } else 2230 return 0; 2231} 2232 2233static int is_hugetlb_entry_hwpoisoned(pte_t pte) 2234{ 2235 swp_entry_t swp; 2236 2237 if (huge_pte_none(pte) || pte_present(pte)) 2238 return 0; 2239 swp = pte_to_swp_entry(pte); 2240 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) { 2241 return 1; 2242 } else 2243 return 0; 2244} 2245 2246void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2247 unsigned long end, struct page *ref_page) 2248{ 2249 struct mm_struct *mm = vma->vm_mm; 2250 unsigned long address; 2251 pte_t *ptep; 2252 pte_t pte; 2253 struct page *page; 2254 struct page *tmp; 2255 struct hstate *h = hstate_vma(vma); 2256 unsigned long sz = huge_page_size(h); 2257 2258 /* 2259 * A page gathering list, protected by per file i_mmap_lock. The 2260 * lock is used to avoid list corruption from multiple unmapping 2261 * of the same page since we are using page->lru. 2262 */ 2263 LIST_HEAD(page_list); 2264 2265 WARN_ON(!is_vm_hugetlb_page(vma)); 2266 BUG_ON(start & ~huge_page_mask(h)); 2267 BUG_ON(end & ~huge_page_mask(h)); 2268 2269 mmu_notifier_invalidate_range_start(mm, start, end); 2270 spin_lock(&mm->page_table_lock); 2271 for (address = start; address < end; address += sz) { 2272 ptep = huge_pte_offset(mm, address); 2273 if (!ptep) 2274 continue; 2275 2276 if (huge_pmd_unshare(mm, &address, ptep)) 2277 continue; 2278 2279 /* 2280 * If a reference page is supplied, it is because a specific 2281 * page is being unmapped, not a range. Ensure the page we 2282 * are about to unmap is the actual page of interest. 2283 */ 2284 if (ref_page) { 2285 pte = huge_ptep_get(ptep); 2286 if (huge_pte_none(pte)) 2287 continue; 2288 page = pte_page(pte); 2289 if (page != ref_page) 2290 continue; 2291 2292 /* 2293 * Mark the VMA as having unmapped its page so that 2294 * future faults in this VMA will fail rather than 2295 * looking like data was lost 2296 */ 2297 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2298 } 2299 2300 pte = huge_ptep_get_and_clear(mm, address, ptep); 2301 if (huge_pte_none(pte)) 2302 continue; 2303 2304 /* 2305 * HWPoisoned hugepage is already unmapped and dropped reference 2306 */ 2307 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) 2308 continue; 2309 2310 page = pte_page(pte); 2311 if (pte_dirty(pte)) 2312 set_page_dirty(page); 2313 list_add(&page->lru, &page_list); 2314 } 2315 spin_unlock(&mm->page_table_lock); 2316 flush_tlb_range(vma, start, end); 2317 mmu_notifier_invalidate_range_end(mm, start, end); 2318 list_for_each_entry_safe(page, tmp, &page_list, lru) { 2319 page_remove_rmap(page); 2320 list_del(&page->lru); 2321 put_page(page); 2322 } 2323} 2324 2325void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2326 unsigned long end, struct page *ref_page) 2327{ 2328 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2329 __unmap_hugepage_range(vma, start, end, ref_page); 2330 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2331} 2332 2333/* 2334 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2335 * mappping it owns the reserve page for. The intention is to unmap the page 2336 * from other VMAs and let the children be SIGKILLed if they are faulting the 2337 * same region. 2338 */ 2339static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2340 struct page *page, unsigned long address) 2341{ 2342 struct hstate *h = hstate_vma(vma); 2343 struct vm_area_struct *iter_vma; 2344 struct address_space *mapping; 2345 struct prio_tree_iter iter; 2346 pgoff_t pgoff; 2347 2348 /* 2349 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2350 * from page cache lookup which is in HPAGE_SIZE units. 2351 */ 2352 address = address & huge_page_mask(h); 2353 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) 2354 + (vma->vm_pgoff >> PAGE_SHIFT); 2355 mapping = (struct address_space *)page_private(page); 2356 2357 /* 2358 * Take the mapping lock for the duration of the table walk. As 2359 * this mapping should be shared between all the VMAs, 2360 * __unmap_hugepage_range() is called as the lock is already held 2361 */ 2362 spin_lock(&mapping->i_mmap_lock); 2363 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { 2364 /* Do not unmap the current VMA */ 2365 if (iter_vma == vma) 2366 continue; 2367 2368 /* 2369 * Unmap the page from other VMAs without their own reserves. 2370 * They get marked to be SIGKILLed if they fault in these 2371 * areas. This is because a future no-page fault on this VMA 2372 * could insert a zeroed page instead of the data existing 2373 * from the time of fork. This would look like data corruption 2374 */ 2375 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2376 __unmap_hugepage_range(iter_vma, 2377 address, address + huge_page_size(h), 2378 page); 2379 } 2380 spin_unlock(&mapping->i_mmap_lock); 2381 2382 return 1; 2383} 2384 2385/* 2386 * Hugetlb_cow() should be called with page lock of the original hugepage held. 2387 */ 2388static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2389 unsigned long address, pte_t *ptep, pte_t pte, 2390 struct page *pagecache_page) 2391{ 2392 struct hstate *h = hstate_vma(vma); 2393 struct page *old_page, *new_page; 2394 int avoidcopy; 2395 int outside_reserve = 0; 2396 2397 old_page = pte_page(pte); 2398 2399retry_avoidcopy: 2400 /* If no-one else is actually using this page, avoid the copy 2401 * and just make the page writable */ 2402 avoidcopy = (page_mapcount(old_page) == 1); 2403 if (avoidcopy) { 2404 if (PageAnon(old_page)) 2405 page_move_anon_rmap(old_page, vma, address); 2406 set_huge_ptep_writable(vma, address, ptep); 2407 return 0; 2408 } 2409 2410 /* 2411 * If the process that created a MAP_PRIVATE mapping is about to 2412 * perform a COW due to a shared page count, attempt to satisfy 2413 * the allocation without using the existing reserves. The pagecache 2414 * page is used to determine if the reserve at this address was 2415 * consumed or not. If reserves were used, a partial faulted mapping 2416 * at the time of fork() could consume its reserves on COW instead 2417 * of the full address range. 2418 */ 2419 if (!(vma->vm_flags & VM_MAYSHARE) && 2420 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2421 old_page != pagecache_page) 2422 outside_reserve = 1; 2423 2424 page_cache_get(old_page); 2425 2426 /* Drop page_table_lock as buddy allocator may be called */ 2427 spin_unlock(&mm->page_table_lock); 2428 new_page = alloc_huge_page(vma, address, outside_reserve); 2429 2430 if (IS_ERR(new_page)) { 2431 page_cache_release(old_page); 2432 2433 /* 2434 * If a process owning a MAP_PRIVATE mapping fails to COW, 2435 * it is due to references held by a child and an insufficient 2436 * huge page pool. To guarantee the original mappers 2437 * reliability, unmap the page from child processes. The child 2438 * may get SIGKILLed if it later faults. 2439 */ 2440 if (outside_reserve) { 2441 BUG_ON(huge_pte_none(pte)); 2442 if (unmap_ref_private(mm, vma, old_page, address)) { 2443 BUG_ON(page_count(old_page) != 1); 2444 BUG_ON(huge_pte_none(pte)); 2445 spin_lock(&mm->page_table_lock); 2446 goto retry_avoidcopy; 2447 } 2448 WARN_ON_ONCE(1); 2449 } 2450 2451 /* Caller expects lock to be held */ 2452 spin_lock(&mm->page_table_lock); 2453 return -PTR_ERR(new_page); 2454 } 2455 2456 /* 2457 * When the original hugepage is shared one, it does not have 2458 * anon_vma prepared. 2459 */ 2460 if (unlikely(anon_vma_prepare(vma))) 2461 return VM_FAULT_OOM; 2462 2463 copy_user_huge_page(new_page, old_page, address, vma); 2464 __SetPageUptodate(new_page); 2465 2466 /* 2467 * Retake the page_table_lock to check for racing updates 2468 * before the page tables are altered 2469 */ 2470 spin_lock(&mm->page_table_lock); 2471 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2472 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2473 /* Break COW */ 2474 mmu_notifier_invalidate_range_start(mm, 2475 address & huge_page_mask(h), 2476 (address & huge_page_mask(h)) + huge_page_size(h)); 2477 huge_ptep_clear_flush(vma, address, ptep); 2478 set_huge_pte_at(mm, address, ptep, 2479 make_huge_pte(vma, new_page, 1)); 2480 page_remove_rmap(old_page); 2481 hugepage_add_new_anon_rmap(new_page, vma, address); 2482 /* Make the old page be freed below */ 2483 new_page = old_page; 2484 mmu_notifier_invalidate_range_end(mm, 2485 address & huge_page_mask(h), 2486 (address & huge_page_mask(h)) + huge_page_size(h)); 2487 } 2488 page_cache_release(new_page); 2489 page_cache_release(old_page); 2490 return 0; 2491} 2492 2493/* Return the pagecache page at a given address within a VMA */ 2494static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2495 struct vm_area_struct *vma, unsigned long address) 2496{ 2497 struct address_space *mapping; 2498 pgoff_t idx; 2499 2500 mapping = vma->vm_file->f_mapping; 2501 idx = vma_hugecache_offset(h, vma, address); 2502 2503 return find_lock_page(mapping, idx); 2504} 2505 2506/* 2507 * Return whether there is a pagecache page to back given address within VMA. 2508 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2509 */ 2510static bool hugetlbfs_pagecache_present(struct hstate *h, 2511 struct vm_area_struct *vma, unsigned long address) 2512{ 2513 struct address_space *mapping; 2514 pgoff_t idx; 2515 struct page *page; 2516 2517 mapping = vma->vm_file->f_mapping; 2518 idx = vma_hugecache_offset(h, vma, address); 2519 2520 page = find_get_page(mapping, idx); 2521 if (page) 2522 put_page(page); 2523 return page != NULL; 2524} 2525 2526static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2527 unsigned long address, pte_t *ptep, unsigned int flags) 2528{ 2529 struct hstate *h = hstate_vma(vma); 2530 int ret = VM_FAULT_SIGBUS; 2531 pgoff_t idx; 2532 unsigned long size; 2533 struct page *page; 2534 struct address_space *mapping; 2535 pte_t new_pte; 2536 2537 /* 2538 * Currently, we are forced to kill the process in the event the 2539 * original mapper has unmapped pages from the child due to a failed 2540 * COW. Warn that such a situation has occured as it may not be obvious 2541 */ 2542 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2543 printk(KERN_WARNING 2544 "PID %d killed due to inadequate hugepage pool\n", 2545 current->pid); 2546 return ret; 2547 } 2548 2549 mapping = vma->vm_file->f_mapping; 2550 idx = vma_hugecache_offset(h, vma, address); 2551 2552 /* 2553 * Use page lock to guard against racing truncation 2554 * before we get page_table_lock. 2555 */ 2556retry: 2557 page = find_lock_page(mapping, idx); 2558 if (!page) { 2559 size = i_size_read(mapping->host) >> huge_page_shift(h); 2560 if (idx >= size) 2561 goto out; 2562 page = alloc_huge_page(vma, address, 0); 2563 if (IS_ERR(page)) { 2564 ret = -PTR_ERR(page); 2565 goto out; 2566 } 2567 clear_huge_page(page, address, huge_page_size(h)); 2568 __SetPageUptodate(page); 2569 2570 if (vma->vm_flags & VM_MAYSHARE) { 2571 int err; 2572 struct inode *inode = mapping->host; 2573 2574 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2575 if (err) { 2576 put_page(page); 2577 if (err == -EEXIST) 2578 goto retry; 2579 goto out; 2580 } 2581 2582 spin_lock(&inode->i_lock); 2583 inode->i_blocks += blocks_per_huge_page(h); 2584 spin_unlock(&inode->i_lock); 2585 page_dup_rmap(page); 2586 } else { 2587 lock_page(page); 2588 if (unlikely(anon_vma_prepare(vma))) { 2589 ret = VM_FAULT_OOM; 2590 goto backout_unlocked; 2591 } 2592 hugepage_add_new_anon_rmap(page, vma, address); 2593 } 2594 } else { 2595 /* 2596 * If memory error occurs between mmap() and fault, some process 2597 * don't have hwpoisoned swap entry for errored virtual address. 2598 * So we need to block hugepage fault by PG_hwpoison bit check. 2599 */ 2600 if (unlikely(PageHWPoison(page))) { 2601 ret = VM_FAULT_HWPOISON; 2602 goto backout_unlocked; 2603 } 2604 page_dup_rmap(page); 2605 } 2606 2607 /* 2608 * If we are going to COW a private mapping later, we examine the 2609 * pending reservations for this page now. This will ensure that 2610 * any allocations necessary to record that reservation occur outside 2611 * the spinlock. 2612 */ 2613 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2614 if (vma_needs_reservation(h, vma, address) < 0) { 2615 ret = VM_FAULT_OOM; 2616 goto backout_unlocked; 2617 } 2618 2619 spin_lock(&mm->page_table_lock); 2620 size = i_size_read(mapping->host) >> huge_page_shift(h); 2621 if (idx >= size) 2622 goto backout; 2623 2624 ret = 0; 2625 if (!huge_pte_none(huge_ptep_get(ptep))) 2626 goto backout; 2627 2628 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2629 && (vma->vm_flags & VM_SHARED))); 2630 set_huge_pte_at(mm, address, ptep, new_pte); 2631 2632 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2633 /* Optimization, do the COW without a second fault */ 2634 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2635 } 2636 2637 spin_unlock(&mm->page_table_lock); 2638 unlock_page(page); 2639out: 2640 return ret; 2641 2642backout: 2643 spin_unlock(&mm->page_table_lock); 2644backout_unlocked: 2645 unlock_page(page); 2646 put_page(page); 2647 goto out; 2648} 2649 2650int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2651 unsigned long address, unsigned int flags) 2652{ 2653 pte_t *ptep; 2654 pte_t entry; 2655 int ret; 2656 struct page *page = NULL; 2657 struct page *pagecache_page = NULL; 2658 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2659 struct hstate *h = hstate_vma(vma); 2660 2661 ptep = huge_pte_offset(mm, address); 2662 if (ptep) { 2663 entry = huge_ptep_get(ptep); 2664 if (unlikely(is_hugetlb_entry_migration(entry))) { 2665 migration_entry_wait(mm, (pmd_t *)ptep, address); 2666 return 0; 2667 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) 2668 return VM_FAULT_HWPOISON; 2669 } 2670 2671 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2672 if (!ptep) 2673 return VM_FAULT_OOM; 2674 2675 /* 2676 * Serialize hugepage allocation and instantiation, so that we don't 2677 * get spurious allocation failures if two CPUs race to instantiate 2678 * the same page in the page cache. 2679 */ 2680 mutex_lock(&hugetlb_instantiation_mutex); 2681 entry = huge_ptep_get(ptep); 2682 if (huge_pte_none(entry)) { 2683 ret = hugetlb_no_page(mm, vma, address, ptep, flags); 2684 goto out_mutex; 2685 } 2686 2687 ret = 0; 2688 2689 /* 2690 * If we are going to COW the mapping later, we examine the pending 2691 * reservations for this page now. This will ensure that any 2692 * allocations necessary to record that reservation occur outside the 2693 * spinlock. For private mappings, we also lookup the pagecache 2694 * page now as it is used to determine if a reservation has been 2695 * consumed. 2696 */ 2697 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) { 2698 if (vma_needs_reservation(h, vma, address) < 0) { 2699 ret = VM_FAULT_OOM; 2700 goto out_mutex; 2701 } 2702 2703 if (!(vma->vm_flags & VM_MAYSHARE)) 2704 pagecache_page = hugetlbfs_pagecache_page(h, 2705 vma, address); 2706 } 2707 2708 /* 2709 * hugetlb_cow() requires page locks of pte_page(entry) and 2710 * pagecache_page, so here we need take the former one 2711 * when page != pagecache_page or !pagecache_page. 2712 * Note that locking order is always pagecache_page -> page, 2713 * so no worry about deadlock. 2714 */ 2715 page = pte_page(entry); 2716 if (page != pagecache_page) 2717 lock_page(page); 2718 2719 spin_lock(&mm->page_table_lock); 2720 /* Check for a racing update before calling hugetlb_cow */ 2721 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2722 goto out_page_table_lock; 2723 2724 2725 if (flags & FAULT_FLAG_WRITE) { 2726 if (!pte_write(entry)) { 2727 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2728 pagecache_page); 2729 goto out_page_table_lock; 2730 } 2731 entry = pte_mkdirty(entry); 2732 } 2733 entry = pte_mkyoung(entry); 2734 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 2735 flags & FAULT_FLAG_WRITE)) 2736 update_mmu_cache(vma, address, ptep); 2737 2738out_page_table_lock: 2739 spin_unlock(&mm->page_table_lock); 2740 2741 if (pagecache_page) { 2742 unlock_page(pagecache_page); 2743 put_page(pagecache_page); 2744 } 2745 unlock_page(page); 2746 2747out_mutex: 2748 mutex_unlock(&hugetlb_instantiation_mutex); 2749 2750 return ret; 2751} 2752 2753/* Can be overriden by architectures */ 2754__attribute__((weak)) struct page * 2755follow_huge_pud(struct mm_struct *mm, unsigned long address, 2756 pud_t *pud, int write) 2757{ 2758 BUG(); 2759 return NULL; 2760} 2761 2762int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2763 struct page **pages, struct vm_area_struct **vmas, 2764 unsigned long *position, int *length, int i, 2765 unsigned int flags) 2766{ 2767 unsigned long pfn_offset; 2768 unsigned long vaddr = *position; 2769 int remainder = *length; 2770 struct hstate *h = hstate_vma(vma); 2771 2772 spin_lock(&mm->page_table_lock); 2773 while (vaddr < vma->vm_end && remainder) { 2774 pte_t *pte; 2775 int absent; 2776 struct page *page; 2777 2778 /* 2779 * Some archs (sparc64, sh*) have multiple pte_ts to 2780 * each hugepage. We have to make sure we get the 2781 * first, for the page indexing below to work. 2782 */ 2783 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2784 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 2785 2786 /* 2787 * When coredumping, it suits get_dump_page if we just return 2788 * an error where there's an empty slot with no huge pagecache 2789 * to back it. This way, we avoid allocating a hugepage, and 2790 * the sparse dumpfile avoids allocating disk blocks, but its 2791 * huge holes still show up with zeroes where they need to be. 2792 */ 2793 if (absent && (flags & FOLL_DUMP) && 2794 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 2795 remainder = 0; 2796 break; 2797 } 2798 2799 if (absent || 2800 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) { 2801 int ret; 2802 2803 spin_unlock(&mm->page_table_lock); 2804 ret = hugetlb_fault(mm, vma, vaddr, 2805 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 2806 spin_lock(&mm->page_table_lock); 2807 if (!(ret & VM_FAULT_ERROR)) 2808 continue; 2809 2810 remainder = 0; 2811 break; 2812 } 2813 2814 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2815 page = pte_page(huge_ptep_get(pte)); 2816same_page: 2817 if (pages) { 2818 pages[i] = mem_map_offset(page, pfn_offset); 2819 get_page(pages[i]); 2820 } 2821 2822 if (vmas) 2823 vmas[i] = vma; 2824 2825 vaddr += PAGE_SIZE; 2826 ++pfn_offset; 2827 --remainder; 2828 ++i; 2829 if (vaddr < vma->vm_end && remainder && 2830 pfn_offset < pages_per_huge_page(h)) { 2831 /* 2832 * We use pfn_offset to avoid touching the pageframes 2833 * of this compound page. 2834 */ 2835 goto same_page; 2836 } 2837 } 2838 spin_unlock(&mm->page_table_lock); 2839 *length = remainder; 2840 *position = vaddr; 2841 2842 return i ? i : -EFAULT; 2843} 2844 2845void hugetlb_change_protection(struct vm_area_struct *vma, 2846 unsigned long address, unsigned long end, pgprot_t newprot) 2847{ 2848 struct mm_struct *mm = vma->vm_mm; 2849 unsigned long start = address; 2850 pte_t *ptep; 2851 pte_t pte; 2852 struct hstate *h = hstate_vma(vma); 2853 2854 BUG_ON(address >= end); 2855 flush_cache_range(vma, address, end); 2856 2857 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2858 spin_lock(&mm->page_table_lock); 2859 for (; address < end; address += huge_page_size(h)) { 2860 ptep = huge_pte_offset(mm, address); 2861 if (!ptep) 2862 continue; 2863 if (huge_pmd_unshare(mm, &address, ptep)) 2864 continue; 2865 if (!huge_pte_none(huge_ptep_get(ptep))) { 2866 pte = huge_ptep_get_and_clear(mm, address, ptep); 2867 pte = pte_mkhuge(pte_modify(pte, newprot)); 2868 set_huge_pte_at(mm, address, ptep, pte); 2869 } 2870 } 2871 spin_unlock(&mm->page_table_lock); 2872 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2873 2874 flush_tlb_range(vma, start, end); 2875} 2876 2877int hugetlb_reserve_pages(struct inode *inode, 2878 long from, long to, 2879 struct vm_area_struct *vma, 2880 int acctflag) 2881{ 2882 long ret, chg; 2883 struct hstate *h = hstate_inode(inode); 2884 2885 /* 2886 * Only apply hugepage reservation if asked. At fault time, an 2887 * attempt will be made for VM_NORESERVE to allocate a page 2888 * and filesystem quota without using reserves 2889 */ 2890 if (acctflag & VM_NORESERVE) 2891 return 0; 2892 2893 /* 2894 * Shared mappings base their reservation on the number of pages that 2895 * are already allocated on behalf of the file. Private mappings need 2896 * to reserve the full area even if read-only as mprotect() may be 2897 * called to make the mapping read-write. Assume !vma is a shm mapping 2898 */ 2899 if (!vma || vma->vm_flags & VM_MAYSHARE) 2900 chg = region_chg(&inode->i_mapping->private_list, from, to); 2901 else { 2902 struct resv_map *resv_map = resv_map_alloc(); 2903 if (!resv_map) 2904 return -ENOMEM; 2905 2906 chg = to - from; 2907 2908 set_vma_resv_map(vma, resv_map); 2909 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 2910 } 2911 2912 if (chg < 0) 2913 return chg; 2914 2915 /* There must be enough filesystem quota for the mapping */ 2916 if (hugetlb_get_quota(inode->i_mapping, chg)) 2917 return -ENOSPC; 2918 2919 /* 2920 * Check enough hugepages are available for the reservation. 2921 * Hand back the quota if there are not 2922 */ 2923 ret = hugetlb_acct_memory(h, chg); 2924 if (ret < 0) { 2925 hugetlb_put_quota(inode->i_mapping, chg); 2926 return ret; 2927 } 2928 2929 /* 2930 * Account for the reservations made. Shared mappings record regions 2931 * that have reservations as they are shared by multiple VMAs. 2932 * When the last VMA disappears, the region map says how much 2933 * the reservation was and the page cache tells how much of 2934 * the reservation was consumed. Private mappings are per-VMA and 2935 * only the consumed reservations are tracked. When the VMA 2936 * disappears, the original reservation is the VMA size and the 2937 * consumed reservations are stored in the map. Hence, nothing 2938 * else has to be done for private mappings here 2939 */ 2940 if (!vma || vma->vm_flags & VM_MAYSHARE) 2941 region_add(&inode->i_mapping->private_list, from, to); 2942 return 0; 2943} 2944 2945void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 2946{ 2947 struct hstate *h = hstate_inode(inode); 2948 long chg = region_truncate(&inode->i_mapping->private_list, offset); 2949 2950 spin_lock(&inode->i_lock); 2951 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 2952 spin_unlock(&inode->i_lock); 2953 2954 hugetlb_put_quota(inode->i_mapping, (chg - freed)); 2955 hugetlb_acct_memory(h, -(chg - freed)); 2956} 2957 2958/* Should be called in hugetlb_lock */ 2959static int is_hugepage_on_freelist(struct page *hpage) 2960{ 2961 struct page *page; 2962 struct page *tmp; 2963 struct hstate *h = page_hstate(hpage); 2964 int nid = page_to_nid(hpage); 2965 2966 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) 2967 if (page == hpage) 2968 return 1; 2969 return 0; 2970} 2971 2972#ifdef CONFIG_MEMORY_FAILURE 2973/* 2974 * This function is called from memory failure code. 2975 * Assume the caller holds page lock of the head page. 2976 */ 2977int dequeue_hwpoisoned_huge_page(struct page *hpage) 2978{ 2979 struct hstate *h = page_hstate(hpage); 2980 int nid = page_to_nid(hpage); 2981 int ret = -EBUSY; 2982 2983 spin_lock(&hugetlb_lock); 2984 if (is_hugepage_on_freelist(hpage)) { 2985 list_del(&hpage->lru); 2986 h->free_huge_pages--; 2987 h->free_huge_pages_node[nid]--; 2988 ret = 0; 2989 } 2990 spin_unlock(&hugetlb_lock); 2991 return ret; 2992} 2993#endif 2994