hugetlb.c revision b0320c7b7d1ac1bd5c2d9dff3258524ab39bad32
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 further 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 copy_gigantic_page(struct page *dst, struct page *src) 398{ 399 int i; 400 struct hstate *h = page_hstate(src); 401 struct page *dst_base = dst; 402 struct page *src_base = src; 403 404 for (i = 0; i < pages_per_huge_page(h); ) { 405 cond_resched(); 406 copy_highpage(dst, src); 407 408 i++; 409 dst = mem_map_next(dst, dst_base, i); 410 src = mem_map_next(src, src_base, i); 411 } 412} 413 414void copy_huge_page(struct page *dst, struct page *src) 415{ 416 int i; 417 struct hstate *h = page_hstate(src); 418 419 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 420 copy_gigantic_page(dst, src); 421 return; 422 } 423 424 might_sleep(); 425 for (i = 0; i < pages_per_huge_page(h); i++) { 426 cond_resched(); 427 copy_highpage(dst + i, src + i); 428 } 429} 430 431static void enqueue_huge_page(struct hstate *h, struct page *page) 432{ 433 int nid = page_to_nid(page); 434 list_add(&page->lru, &h->hugepage_freelists[nid]); 435 h->free_huge_pages++; 436 h->free_huge_pages_node[nid]++; 437} 438 439static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 440{ 441 struct page *page; 442 443 if (list_empty(&h->hugepage_freelists[nid])) 444 return NULL; 445 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); 446 list_del(&page->lru); 447 set_page_refcounted(page); 448 h->free_huge_pages--; 449 h->free_huge_pages_node[nid]--; 450 return page; 451} 452 453static struct page *dequeue_huge_page_vma(struct hstate *h, 454 struct vm_area_struct *vma, 455 unsigned long address, int avoid_reserve) 456{ 457 struct page *page = NULL; 458 struct mempolicy *mpol; 459 nodemask_t *nodemask; 460 struct zonelist *zonelist; 461 struct zone *zone; 462 struct zoneref *z; 463 464 get_mems_allowed(); 465 zonelist = huge_zonelist(vma, address, 466 htlb_alloc_mask, &mpol, &nodemask); 467 /* 468 * A child process with MAP_PRIVATE mappings created by their parent 469 * have no page reserves. This check ensures that reservations are 470 * not "stolen". The child may still get SIGKILLed 471 */ 472 if (!vma_has_reserves(vma) && 473 h->free_huge_pages - h->resv_huge_pages == 0) 474 goto err; 475 476 /* If reserves cannot be used, ensure enough pages are in the pool */ 477 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 478 goto err; 479 480 for_each_zone_zonelist_nodemask(zone, z, zonelist, 481 MAX_NR_ZONES - 1, nodemask) { 482 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { 483 page = dequeue_huge_page_node(h, zone_to_nid(zone)); 484 if (page) { 485 if (!avoid_reserve) 486 decrement_hugepage_resv_vma(h, vma); 487 break; 488 } 489 } 490 } 491err: 492 mpol_cond_put(mpol); 493 put_mems_allowed(); 494 return page; 495} 496 497static void update_and_free_page(struct hstate *h, struct page *page) 498{ 499 int i; 500 501 VM_BUG_ON(h->order >= MAX_ORDER); 502 503 h->nr_huge_pages--; 504 h->nr_huge_pages_node[page_to_nid(page)]--; 505 for (i = 0; i < pages_per_huge_page(h); i++) { 506 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 507 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 508 1 << PG_private | 1<< PG_writeback); 509 } 510 set_compound_page_dtor(page, NULL); 511 set_page_refcounted(page); 512 arch_release_hugepage(page); 513 __free_pages(page, huge_page_order(h)); 514} 515 516struct hstate *size_to_hstate(unsigned long size) 517{ 518 struct hstate *h; 519 520 for_each_hstate(h) { 521 if (huge_page_size(h) == size) 522 return h; 523 } 524 return NULL; 525} 526 527static void free_huge_page(struct page *page) 528{ 529 /* 530 * Can't pass hstate in here because it is called from the 531 * compound page destructor. 532 */ 533 struct hstate *h = page_hstate(page); 534 int nid = page_to_nid(page); 535 struct address_space *mapping; 536 537 mapping = (struct address_space *) page_private(page); 538 set_page_private(page, 0); 539 page->mapping = NULL; 540 BUG_ON(page_count(page)); 541 BUG_ON(page_mapcount(page)); 542 INIT_LIST_HEAD(&page->lru); 543 544 spin_lock(&hugetlb_lock); 545 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 546 update_and_free_page(h, page); 547 h->surplus_huge_pages--; 548 h->surplus_huge_pages_node[nid]--; 549 } else { 550 enqueue_huge_page(h, page); 551 } 552 spin_unlock(&hugetlb_lock); 553 if (mapping) 554 hugetlb_put_quota(mapping, 1); 555} 556 557static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 558{ 559 set_compound_page_dtor(page, free_huge_page); 560 spin_lock(&hugetlb_lock); 561 h->nr_huge_pages++; 562 h->nr_huge_pages_node[nid]++; 563 spin_unlock(&hugetlb_lock); 564 put_page(page); /* free it into the hugepage allocator */ 565} 566 567static void prep_compound_gigantic_page(struct page *page, unsigned long order) 568{ 569 int i; 570 int nr_pages = 1 << order; 571 struct page *p = page + 1; 572 573 /* we rely on prep_new_huge_page to set the destructor */ 574 set_compound_order(page, order); 575 __SetPageHead(page); 576 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 577 __SetPageTail(p); 578 p->first_page = page; 579 } 580} 581 582int PageHuge(struct page *page) 583{ 584 compound_page_dtor *dtor; 585 586 if (!PageCompound(page)) 587 return 0; 588 589 page = compound_head(page); 590 dtor = get_compound_page_dtor(page); 591 592 return dtor == free_huge_page; 593} 594 595EXPORT_SYMBOL_GPL(PageHuge); 596 597static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 598{ 599 struct page *page; 600 601 if (h->order >= MAX_ORDER) 602 return NULL; 603 604 page = alloc_pages_exact_node(nid, 605 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 606 __GFP_REPEAT|__GFP_NOWARN, 607 huge_page_order(h)); 608 if (page) { 609 if (arch_prepare_hugepage(page)) { 610 __free_pages(page, huge_page_order(h)); 611 return NULL; 612 } 613 prep_new_huge_page(h, page, nid); 614 } 615 616 return page; 617} 618 619/* 620 * common helper functions for hstate_next_node_to_{alloc|free}. 621 * We may have allocated or freed a huge page based on a different 622 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 623 * be outside of *nodes_allowed. Ensure that we use an allowed 624 * node for alloc or free. 625 */ 626static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 627{ 628 nid = next_node(nid, *nodes_allowed); 629 if (nid == MAX_NUMNODES) 630 nid = first_node(*nodes_allowed); 631 VM_BUG_ON(nid >= MAX_NUMNODES); 632 633 return nid; 634} 635 636static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 637{ 638 if (!node_isset(nid, *nodes_allowed)) 639 nid = next_node_allowed(nid, nodes_allowed); 640 return nid; 641} 642 643/* 644 * returns the previously saved node ["this node"] from which to 645 * allocate a persistent huge page for the pool and advance the 646 * next node from which to allocate, handling wrap at end of node 647 * mask. 648 */ 649static int hstate_next_node_to_alloc(struct hstate *h, 650 nodemask_t *nodes_allowed) 651{ 652 int nid; 653 654 VM_BUG_ON(!nodes_allowed); 655 656 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 657 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 658 659 return nid; 660} 661 662static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 663{ 664 struct page *page; 665 int start_nid; 666 int next_nid; 667 int ret = 0; 668 669 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 670 next_nid = start_nid; 671 672 do { 673 page = alloc_fresh_huge_page_node(h, next_nid); 674 if (page) { 675 ret = 1; 676 break; 677 } 678 next_nid = hstate_next_node_to_alloc(h, nodes_allowed); 679 } while (next_nid != start_nid); 680 681 if (ret) 682 count_vm_event(HTLB_BUDDY_PGALLOC); 683 else 684 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 685 686 return ret; 687} 688 689/* 690 * helper for free_pool_huge_page() - return the previously saved 691 * node ["this node"] from which to free a huge page. Advance the 692 * next node id whether or not we find a free huge page to free so 693 * that the next attempt to free addresses the next node. 694 */ 695static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 696{ 697 int nid; 698 699 VM_BUG_ON(!nodes_allowed); 700 701 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 702 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 703 704 return nid; 705} 706 707/* 708 * Free huge page from pool from next node to free. 709 * Attempt to keep persistent huge pages more or less 710 * balanced over allowed nodes. 711 * Called with hugetlb_lock locked. 712 */ 713static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 714 bool acct_surplus) 715{ 716 int start_nid; 717 int next_nid; 718 int ret = 0; 719 720 start_nid = hstate_next_node_to_free(h, nodes_allowed); 721 next_nid = start_nid; 722 723 do { 724 /* 725 * If we're returning unused surplus pages, only examine 726 * nodes with surplus pages. 727 */ 728 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && 729 !list_empty(&h->hugepage_freelists[next_nid])) { 730 struct page *page = 731 list_entry(h->hugepage_freelists[next_nid].next, 732 struct page, lru); 733 list_del(&page->lru); 734 h->free_huge_pages--; 735 h->free_huge_pages_node[next_nid]--; 736 if (acct_surplus) { 737 h->surplus_huge_pages--; 738 h->surplus_huge_pages_node[next_nid]--; 739 } 740 update_and_free_page(h, page); 741 ret = 1; 742 break; 743 } 744 next_nid = hstate_next_node_to_free(h, nodes_allowed); 745 } while (next_nid != start_nid); 746 747 return ret; 748} 749 750static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) 751{ 752 struct page *page; 753 unsigned int r_nid; 754 755 if (h->order >= MAX_ORDER) 756 return NULL; 757 758 /* 759 * Assume we will successfully allocate the surplus page to 760 * prevent racing processes from causing the surplus to exceed 761 * overcommit 762 * 763 * This however introduces a different race, where a process B 764 * tries to grow the static hugepage pool while alloc_pages() is 765 * called by process A. B will only examine the per-node 766 * counters in determining if surplus huge pages can be 767 * converted to normal huge pages in adjust_pool_surplus(). A 768 * won't be able to increment the per-node counter, until the 769 * lock is dropped by B, but B doesn't drop hugetlb_lock until 770 * no more huge pages can be converted from surplus to normal 771 * state (and doesn't try to convert again). Thus, we have a 772 * case where a surplus huge page exists, the pool is grown, and 773 * the surplus huge page still exists after, even though it 774 * should just have been converted to a normal huge page. This 775 * does not leak memory, though, as the hugepage will be freed 776 * once it is out of use. It also does not allow the counters to 777 * go out of whack in adjust_pool_surplus() as we don't modify 778 * the node values until we've gotten the hugepage and only the 779 * per-node value is checked there. 780 */ 781 spin_lock(&hugetlb_lock); 782 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 783 spin_unlock(&hugetlb_lock); 784 return NULL; 785 } else { 786 h->nr_huge_pages++; 787 h->surplus_huge_pages++; 788 } 789 spin_unlock(&hugetlb_lock); 790 791 if (nid == NUMA_NO_NODE) 792 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 793 __GFP_REPEAT|__GFP_NOWARN, 794 huge_page_order(h)); 795 else 796 page = alloc_pages_exact_node(nid, 797 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 798 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); 799 800 if (page && arch_prepare_hugepage(page)) { 801 __free_pages(page, huge_page_order(h)); 802 return NULL; 803 } 804 805 spin_lock(&hugetlb_lock); 806 if (page) { 807 r_nid = page_to_nid(page); 808 set_compound_page_dtor(page, free_huge_page); 809 /* 810 * We incremented the global counters already 811 */ 812 h->nr_huge_pages_node[r_nid]++; 813 h->surplus_huge_pages_node[r_nid]++; 814 __count_vm_event(HTLB_BUDDY_PGALLOC); 815 } else { 816 h->nr_huge_pages--; 817 h->surplus_huge_pages--; 818 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 819 } 820 spin_unlock(&hugetlb_lock); 821 822 return page; 823} 824 825/* 826 * This allocation function is useful in the context where vma is irrelevant. 827 * E.g. soft-offlining uses this function because it only cares physical 828 * address of error page. 829 */ 830struct page *alloc_huge_page_node(struct hstate *h, int nid) 831{ 832 struct page *page; 833 834 spin_lock(&hugetlb_lock); 835 page = dequeue_huge_page_node(h, nid); 836 spin_unlock(&hugetlb_lock); 837 838 if (!page) 839 page = alloc_buddy_huge_page(h, nid); 840 841 return page; 842} 843 844/* 845 * Increase the hugetlb pool such that it can accommodate a reservation 846 * of size 'delta'. 847 */ 848static int gather_surplus_pages(struct hstate *h, int delta) 849{ 850 struct list_head surplus_list; 851 struct page *page, *tmp; 852 int ret, i; 853 int needed, allocated; 854 855 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 856 if (needed <= 0) { 857 h->resv_huge_pages += delta; 858 return 0; 859 } 860 861 allocated = 0; 862 INIT_LIST_HEAD(&surplus_list); 863 864 ret = -ENOMEM; 865retry: 866 spin_unlock(&hugetlb_lock); 867 for (i = 0; i < needed; i++) { 868 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 869 if (!page) 870 /* 871 * We were not able to allocate enough pages to 872 * satisfy the entire reservation so we free what 873 * we've allocated so far. 874 */ 875 goto free; 876 877 list_add(&page->lru, &surplus_list); 878 } 879 allocated += needed; 880 881 /* 882 * After retaking hugetlb_lock, we need to recalculate 'needed' 883 * because either resv_huge_pages or free_huge_pages may have changed. 884 */ 885 spin_lock(&hugetlb_lock); 886 needed = (h->resv_huge_pages + delta) - 887 (h->free_huge_pages + allocated); 888 if (needed > 0) 889 goto retry; 890 891 /* 892 * The surplus_list now contains _at_least_ the number of extra pages 893 * needed to accommodate the reservation. Add the appropriate number 894 * of pages to the hugetlb pool and free the extras back to the buddy 895 * allocator. Commit the entire reservation here to prevent another 896 * process from stealing the pages as they are added to the pool but 897 * before they are reserved. 898 */ 899 needed += allocated; 900 h->resv_huge_pages += delta; 901 ret = 0; 902 903 spin_unlock(&hugetlb_lock); 904 /* Free the needed pages to the hugetlb pool */ 905 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 906 if ((--needed) < 0) 907 break; 908 list_del(&page->lru); 909 /* 910 * This page is now managed by the hugetlb allocator and has 911 * no users -- drop the buddy allocator's reference. 912 */ 913 put_page_testzero(page); 914 VM_BUG_ON(page_count(page)); 915 enqueue_huge_page(h, page); 916 } 917 918 /* Free unnecessary surplus pages to the buddy allocator */ 919free: 920 if (!list_empty(&surplus_list)) { 921 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 922 list_del(&page->lru); 923 put_page(page); 924 } 925 } 926 spin_lock(&hugetlb_lock); 927 928 return ret; 929} 930 931/* 932 * When releasing a hugetlb pool reservation, any surplus pages that were 933 * allocated to satisfy the reservation must be explicitly freed if they were 934 * never used. 935 * Called with hugetlb_lock held. 936 */ 937static void return_unused_surplus_pages(struct hstate *h, 938 unsigned long unused_resv_pages) 939{ 940 unsigned long nr_pages; 941 942 /* Uncommit the reservation */ 943 h->resv_huge_pages -= unused_resv_pages; 944 945 /* Cannot return gigantic pages currently */ 946 if (h->order >= MAX_ORDER) 947 return; 948 949 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 950 951 /* 952 * We want to release as many surplus pages as possible, spread 953 * evenly across all nodes with memory. Iterate across these nodes 954 * until we can no longer free unreserved surplus pages. This occurs 955 * when the nodes with surplus pages have no free pages. 956 * free_pool_huge_page() will balance the the freed pages across the 957 * on-line nodes with memory and will handle the hstate accounting. 958 */ 959 while (nr_pages--) { 960 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1)) 961 break; 962 } 963} 964 965/* 966 * Determine if the huge page at addr within the vma has an associated 967 * reservation. Where it does not we will need to logically increase 968 * reservation and actually increase quota before an allocation can occur. 969 * Where any new reservation would be required the reservation change is 970 * prepared, but not committed. Once the page has been quota'd allocated 971 * an instantiated the change should be committed via vma_commit_reservation. 972 * No action is required on failure. 973 */ 974static long vma_needs_reservation(struct hstate *h, 975 struct vm_area_struct *vma, unsigned long addr) 976{ 977 struct address_space *mapping = vma->vm_file->f_mapping; 978 struct inode *inode = mapping->host; 979 980 if (vma->vm_flags & VM_MAYSHARE) { 981 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 982 return region_chg(&inode->i_mapping->private_list, 983 idx, idx + 1); 984 985 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 986 return 1; 987 988 } else { 989 long err; 990 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 991 struct resv_map *reservations = vma_resv_map(vma); 992 993 err = region_chg(&reservations->regions, idx, idx + 1); 994 if (err < 0) 995 return err; 996 return 0; 997 } 998} 999static void vma_commit_reservation(struct hstate *h, 1000 struct vm_area_struct *vma, unsigned long addr) 1001{ 1002 struct address_space *mapping = vma->vm_file->f_mapping; 1003 struct inode *inode = mapping->host; 1004 1005 if (vma->vm_flags & VM_MAYSHARE) { 1006 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1007 region_add(&inode->i_mapping->private_list, idx, idx + 1); 1008 1009 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1010 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1011 struct resv_map *reservations = vma_resv_map(vma); 1012 1013 /* Mark this page used in the map. */ 1014 region_add(&reservations->regions, idx, idx + 1); 1015 } 1016} 1017 1018static struct page *alloc_huge_page(struct vm_area_struct *vma, 1019 unsigned long addr, int avoid_reserve) 1020{ 1021 struct hstate *h = hstate_vma(vma); 1022 struct page *page; 1023 struct address_space *mapping = vma->vm_file->f_mapping; 1024 struct inode *inode = mapping->host; 1025 long chg; 1026 1027 /* 1028 * Processes that did not create the mapping will have no reserves and 1029 * will not have accounted against quota. Check that the quota can be 1030 * made before satisfying the allocation 1031 * MAP_NORESERVE mappings may also need pages and quota allocated 1032 * if no reserve mapping overlaps. 1033 */ 1034 chg = vma_needs_reservation(h, vma, addr); 1035 if (chg < 0) 1036 return ERR_PTR(-VM_FAULT_OOM); 1037 if (chg) 1038 if (hugetlb_get_quota(inode->i_mapping, chg)) 1039 return ERR_PTR(-VM_FAULT_SIGBUS); 1040 1041 spin_lock(&hugetlb_lock); 1042 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 1043 spin_unlock(&hugetlb_lock); 1044 1045 if (!page) { 1046 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1047 if (!page) { 1048 hugetlb_put_quota(inode->i_mapping, chg); 1049 return ERR_PTR(-VM_FAULT_SIGBUS); 1050 } 1051 } 1052 1053 set_page_private(page, (unsigned long) mapping); 1054 1055 vma_commit_reservation(h, vma, addr); 1056 1057 return page; 1058} 1059 1060int __weak alloc_bootmem_huge_page(struct hstate *h) 1061{ 1062 struct huge_bootmem_page *m; 1063 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]); 1064 1065 while (nr_nodes) { 1066 void *addr; 1067 1068 addr = __alloc_bootmem_node_nopanic( 1069 NODE_DATA(hstate_next_node_to_alloc(h, 1070 &node_states[N_HIGH_MEMORY])), 1071 huge_page_size(h), huge_page_size(h), 0); 1072 1073 if (addr) { 1074 /* 1075 * Use the beginning of the huge page to store the 1076 * huge_bootmem_page struct (until gather_bootmem 1077 * puts them into the mem_map). 1078 */ 1079 m = addr; 1080 goto found; 1081 } 1082 nr_nodes--; 1083 } 1084 return 0; 1085 1086found: 1087 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1088 /* Put them into a private list first because mem_map is not up yet */ 1089 list_add(&m->list, &huge_boot_pages); 1090 m->hstate = h; 1091 return 1; 1092} 1093 1094static void prep_compound_huge_page(struct page *page, int order) 1095{ 1096 if (unlikely(order > (MAX_ORDER - 1))) 1097 prep_compound_gigantic_page(page, order); 1098 else 1099 prep_compound_page(page, order); 1100} 1101 1102/* Put bootmem huge pages into the standard lists after mem_map is up */ 1103static void __init gather_bootmem_prealloc(void) 1104{ 1105 struct huge_bootmem_page *m; 1106 1107 list_for_each_entry(m, &huge_boot_pages, list) { 1108 struct page *page = virt_to_page(m); 1109 struct hstate *h = m->hstate; 1110 __ClearPageReserved(page); 1111 WARN_ON(page_count(page) != 1); 1112 prep_compound_huge_page(page, h->order); 1113 prep_new_huge_page(h, page, page_to_nid(page)); 1114 /* 1115 * If we had gigantic hugepages allocated at boot time, we need 1116 * to restore the 'stolen' pages to totalram_pages in order to 1117 * fix confusing memory reports from free(1) and another 1118 * side-effects, like CommitLimit going negative. 1119 */ 1120 if (h->order > (MAX_ORDER - 1)) 1121 totalram_pages += 1 << h->order; 1122 } 1123} 1124 1125static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1126{ 1127 unsigned long i; 1128 1129 for (i = 0; i < h->max_huge_pages; ++i) { 1130 if (h->order >= MAX_ORDER) { 1131 if (!alloc_bootmem_huge_page(h)) 1132 break; 1133 } else if (!alloc_fresh_huge_page(h, 1134 &node_states[N_HIGH_MEMORY])) 1135 break; 1136 } 1137 h->max_huge_pages = i; 1138} 1139 1140static void __init hugetlb_init_hstates(void) 1141{ 1142 struct hstate *h; 1143 1144 for_each_hstate(h) { 1145 /* oversize hugepages were init'ed in early boot */ 1146 if (h->order < MAX_ORDER) 1147 hugetlb_hstate_alloc_pages(h); 1148 } 1149} 1150 1151static char * __init memfmt(char *buf, unsigned long n) 1152{ 1153 if (n >= (1UL << 30)) 1154 sprintf(buf, "%lu GB", n >> 30); 1155 else if (n >= (1UL << 20)) 1156 sprintf(buf, "%lu MB", n >> 20); 1157 else 1158 sprintf(buf, "%lu KB", n >> 10); 1159 return buf; 1160} 1161 1162static void __init report_hugepages(void) 1163{ 1164 struct hstate *h; 1165 1166 for_each_hstate(h) { 1167 char buf[32]; 1168 printk(KERN_INFO "HugeTLB registered %s page size, " 1169 "pre-allocated %ld pages\n", 1170 memfmt(buf, huge_page_size(h)), 1171 h->free_huge_pages); 1172 } 1173} 1174 1175#ifdef CONFIG_HIGHMEM 1176static void try_to_free_low(struct hstate *h, unsigned long count, 1177 nodemask_t *nodes_allowed) 1178{ 1179 int i; 1180 1181 if (h->order >= MAX_ORDER) 1182 return; 1183 1184 for_each_node_mask(i, *nodes_allowed) { 1185 struct page *page, *next; 1186 struct list_head *freel = &h->hugepage_freelists[i]; 1187 list_for_each_entry_safe(page, next, freel, lru) { 1188 if (count >= h->nr_huge_pages) 1189 return; 1190 if (PageHighMem(page)) 1191 continue; 1192 list_del(&page->lru); 1193 update_and_free_page(h, page); 1194 h->free_huge_pages--; 1195 h->free_huge_pages_node[page_to_nid(page)]--; 1196 } 1197 } 1198} 1199#else 1200static inline void try_to_free_low(struct hstate *h, unsigned long count, 1201 nodemask_t *nodes_allowed) 1202{ 1203} 1204#endif 1205 1206/* 1207 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1208 * balanced by operating on them in a round-robin fashion. 1209 * Returns 1 if an adjustment was made. 1210 */ 1211static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1212 int delta) 1213{ 1214 int start_nid, next_nid; 1215 int ret = 0; 1216 1217 VM_BUG_ON(delta != -1 && delta != 1); 1218 1219 if (delta < 0) 1220 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 1221 else 1222 start_nid = hstate_next_node_to_free(h, nodes_allowed); 1223 next_nid = start_nid; 1224 1225 do { 1226 int nid = next_nid; 1227 if (delta < 0) { 1228 /* 1229 * To shrink on this node, there must be a surplus page 1230 */ 1231 if (!h->surplus_huge_pages_node[nid]) { 1232 next_nid = hstate_next_node_to_alloc(h, 1233 nodes_allowed); 1234 continue; 1235 } 1236 } 1237 if (delta > 0) { 1238 /* 1239 * Surplus cannot exceed the total number of pages 1240 */ 1241 if (h->surplus_huge_pages_node[nid] >= 1242 h->nr_huge_pages_node[nid]) { 1243 next_nid = hstate_next_node_to_free(h, 1244 nodes_allowed); 1245 continue; 1246 } 1247 } 1248 1249 h->surplus_huge_pages += delta; 1250 h->surplus_huge_pages_node[nid] += delta; 1251 ret = 1; 1252 break; 1253 } while (next_nid != start_nid); 1254 1255 return ret; 1256} 1257 1258#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1259static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1260 nodemask_t *nodes_allowed) 1261{ 1262 unsigned long min_count, ret; 1263 1264 if (h->order >= MAX_ORDER) 1265 return h->max_huge_pages; 1266 1267 /* 1268 * Increase the pool size 1269 * First take pages out of surplus state. Then make up the 1270 * remaining difference by allocating fresh huge pages. 1271 * 1272 * We might race with alloc_buddy_huge_page() here and be unable 1273 * to convert a surplus huge page to a normal huge page. That is 1274 * not critical, though, it just means the overall size of the 1275 * pool might be one hugepage larger than it needs to be, but 1276 * within all the constraints specified by the sysctls. 1277 */ 1278 spin_lock(&hugetlb_lock); 1279 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1280 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1281 break; 1282 } 1283 1284 while (count > persistent_huge_pages(h)) { 1285 /* 1286 * If this allocation races such that we no longer need the 1287 * page, free_huge_page will handle it by freeing the page 1288 * and reducing the surplus. 1289 */ 1290 spin_unlock(&hugetlb_lock); 1291 ret = alloc_fresh_huge_page(h, nodes_allowed); 1292 spin_lock(&hugetlb_lock); 1293 if (!ret) 1294 goto out; 1295 1296 /* Bail for signals. Probably ctrl-c from user */ 1297 if (signal_pending(current)) 1298 goto out; 1299 } 1300 1301 /* 1302 * Decrease the pool size 1303 * First return free pages to the buddy allocator (being careful 1304 * to keep enough around to satisfy reservations). Then place 1305 * pages into surplus state as needed so the pool will shrink 1306 * to the desired size as pages become free. 1307 * 1308 * By placing pages into the surplus state independent of the 1309 * overcommit value, we are allowing the surplus pool size to 1310 * exceed overcommit. There are few sane options here. Since 1311 * alloc_buddy_huge_page() is checking the global counter, 1312 * though, we'll note that we're not allowed to exceed surplus 1313 * and won't grow the pool anywhere else. Not until one of the 1314 * sysctls are changed, or the surplus pages go out of use. 1315 */ 1316 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1317 min_count = max(count, min_count); 1318 try_to_free_low(h, min_count, nodes_allowed); 1319 while (min_count < persistent_huge_pages(h)) { 1320 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1321 break; 1322 } 1323 while (count < persistent_huge_pages(h)) { 1324 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1325 break; 1326 } 1327out: 1328 ret = persistent_huge_pages(h); 1329 spin_unlock(&hugetlb_lock); 1330 return ret; 1331} 1332 1333#define HSTATE_ATTR_RO(_name) \ 1334 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1335 1336#define HSTATE_ATTR(_name) \ 1337 static struct kobj_attribute _name##_attr = \ 1338 __ATTR(_name, 0644, _name##_show, _name##_store) 1339 1340static struct kobject *hugepages_kobj; 1341static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1342 1343static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1344 1345static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1346{ 1347 int i; 1348 1349 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1350 if (hstate_kobjs[i] == kobj) { 1351 if (nidp) 1352 *nidp = NUMA_NO_NODE; 1353 return &hstates[i]; 1354 } 1355 1356 return kobj_to_node_hstate(kobj, nidp); 1357} 1358 1359static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1360 struct kobj_attribute *attr, char *buf) 1361{ 1362 struct hstate *h; 1363 unsigned long nr_huge_pages; 1364 int nid; 1365 1366 h = kobj_to_hstate(kobj, &nid); 1367 if (nid == NUMA_NO_NODE) 1368 nr_huge_pages = h->nr_huge_pages; 1369 else 1370 nr_huge_pages = h->nr_huge_pages_node[nid]; 1371 1372 return sprintf(buf, "%lu\n", nr_huge_pages); 1373} 1374 1375static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1376 struct kobject *kobj, struct kobj_attribute *attr, 1377 const char *buf, size_t len) 1378{ 1379 int err; 1380 int nid; 1381 unsigned long count; 1382 struct hstate *h; 1383 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1384 1385 err = strict_strtoul(buf, 10, &count); 1386 if (err) 1387 goto out; 1388 1389 h = kobj_to_hstate(kobj, &nid); 1390 if (h->order >= MAX_ORDER) { 1391 err = -EINVAL; 1392 goto out; 1393 } 1394 1395 if (nid == NUMA_NO_NODE) { 1396 /* 1397 * global hstate attribute 1398 */ 1399 if (!(obey_mempolicy && 1400 init_nodemask_of_mempolicy(nodes_allowed))) { 1401 NODEMASK_FREE(nodes_allowed); 1402 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1403 } 1404 } else if (nodes_allowed) { 1405 /* 1406 * per node hstate attribute: adjust count to global, 1407 * but restrict alloc/free to the specified node. 1408 */ 1409 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1410 init_nodemask_of_node(nodes_allowed, nid); 1411 } else 1412 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1413 1414 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1415 1416 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1417 NODEMASK_FREE(nodes_allowed); 1418 1419 return len; 1420out: 1421 NODEMASK_FREE(nodes_allowed); 1422 return err; 1423} 1424 1425static ssize_t nr_hugepages_show(struct kobject *kobj, 1426 struct kobj_attribute *attr, char *buf) 1427{ 1428 return nr_hugepages_show_common(kobj, attr, buf); 1429} 1430 1431static ssize_t nr_hugepages_store(struct kobject *kobj, 1432 struct kobj_attribute *attr, const char *buf, size_t len) 1433{ 1434 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1435} 1436HSTATE_ATTR(nr_hugepages); 1437 1438#ifdef CONFIG_NUMA 1439 1440/* 1441 * hstate attribute for optionally mempolicy-based constraint on persistent 1442 * huge page alloc/free. 1443 */ 1444static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1445 struct kobj_attribute *attr, char *buf) 1446{ 1447 return nr_hugepages_show_common(kobj, attr, buf); 1448} 1449 1450static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1451 struct kobj_attribute *attr, const char *buf, size_t len) 1452{ 1453 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1454} 1455HSTATE_ATTR(nr_hugepages_mempolicy); 1456#endif 1457 1458 1459static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1460 struct kobj_attribute *attr, char *buf) 1461{ 1462 struct hstate *h = kobj_to_hstate(kobj, NULL); 1463 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1464} 1465 1466static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1467 struct kobj_attribute *attr, const char *buf, size_t count) 1468{ 1469 int err; 1470 unsigned long input; 1471 struct hstate *h = kobj_to_hstate(kobj, NULL); 1472 1473 if (h->order >= MAX_ORDER) 1474 return -EINVAL; 1475 1476 err = strict_strtoul(buf, 10, &input); 1477 if (err) 1478 return err; 1479 1480 spin_lock(&hugetlb_lock); 1481 h->nr_overcommit_huge_pages = input; 1482 spin_unlock(&hugetlb_lock); 1483 1484 return count; 1485} 1486HSTATE_ATTR(nr_overcommit_hugepages); 1487 1488static ssize_t free_hugepages_show(struct kobject *kobj, 1489 struct kobj_attribute *attr, char *buf) 1490{ 1491 struct hstate *h; 1492 unsigned long free_huge_pages; 1493 int nid; 1494 1495 h = kobj_to_hstate(kobj, &nid); 1496 if (nid == NUMA_NO_NODE) 1497 free_huge_pages = h->free_huge_pages; 1498 else 1499 free_huge_pages = h->free_huge_pages_node[nid]; 1500 1501 return sprintf(buf, "%lu\n", free_huge_pages); 1502} 1503HSTATE_ATTR_RO(free_hugepages); 1504 1505static ssize_t resv_hugepages_show(struct kobject *kobj, 1506 struct kobj_attribute *attr, char *buf) 1507{ 1508 struct hstate *h = kobj_to_hstate(kobj, NULL); 1509 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1510} 1511HSTATE_ATTR_RO(resv_hugepages); 1512 1513static ssize_t surplus_hugepages_show(struct kobject *kobj, 1514 struct kobj_attribute *attr, char *buf) 1515{ 1516 struct hstate *h; 1517 unsigned long surplus_huge_pages; 1518 int nid; 1519 1520 h = kobj_to_hstate(kobj, &nid); 1521 if (nid == NUMA_NO_NODE) 1522 surplus_huge_pages = h->surplus_huge_pages; 1523 else 1524 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1525 1526 return sprintf(buf, "%lu\n", surplus_huge_pages); 1527} 1528HSTATE_ATTR_RO(surplus_hugepages); 1529 1530static struct attribute *hstate_attrs[] = { 1531 &nr_hugepages_attr.attr, 1532 &nr_overcommit_hugepages_attr.attr, 1533 &free_hugepages_attr.attr, 1534 &resv_hugepages_attr.attr, 1535 &surplus_hugepages_attr.attr, 1536#ifdef CONFIG_NUMA 1537 &nr_hugepages_mempolicy_attr.attr, 1538#endif 1539 NULL, 1540}; 1541 1542static struct attribute_group hstate_attr_group = { 1543 .attrs = hstate_attrs, 1544}; 1545 1546static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, 1547 struct kobject **hstate_kobjs, 1548 struct attribute_group *hstate_attr_group) 1549{ 1550 int retval; 1551 int hi = h - hstates; 1552 1553 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1554 if (!hstate_kobjs[hi]) 1555 return -ENOMEM; 1556 1557 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1558 if (retval) 1559 kobject_put(hstate_kobjs[hi]); 1560 1561 return retval; 1562} 1563 1564static void __init hugetlb_sysfs_init(void) 1565{ 1566 struct hstate *h; 1567 int err; 1568 1569 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1570 if (!hugepages_kobj) 1571 return; 1572 1573 for_each_hstate(h) { 1574 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1575 hstate_kobjs, &hstate_attr_group); 1576 if (err) 1577 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1578 h->name); 1579 } 1580} 1581 1582#ifdef CONFIG_NUMA 1583 1584/* 1585 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1586 * with node sysdevs in node_devices[] using a parallel array. The array 1587 * index of a node sysdev or _hstate == node id. 1588 * This is here to avoid any static dependency of the node sysdev driver, in 1589 * the base kernel, on the hugetlb module. 1590 */ 1591struct node_hstate { 1592 struct kobject *hugepages_kobj; 1593 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1594}; 1595struct node_hstate node_hstates[MAX_NUMNODES]; 1596 1597/* 1598 * A subset of global hstate attributes for node sysdevs 1599 */ 1600static struct attribute *per_node_hstate_attrs[] = { 1601 &nr_hugepages_attr.attr, 1602 &free_hugepages_attr.attr, 1603 &surplus_hugepages_attr.attr, 1604 NULL, 1605}; 1606 1607static struct attribute_group per_node_hstate_attr_group = { 1608 .attrs = per_node_hstate_attrs, 1609}; 1610 1611/* 1612 * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj. 1613 * Returns node id via non-NULL nidp. 1614 */ 1615static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1616{ 1617 int nid; 1618 1619 for (nid = 0; nid < nr_node_ids; nid++) { 1620 struct node_hstate *nhs = &node_hstates[nid]; 1621 int i; 1622 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1623 if (nhs->hstate_kobjs[i] == kobj) { 1624 if (nidp) 1625 *nidp = nid; 1626 return &hstates[i]; 1627 } 1628 } 1629 1630 BUG(); 1631 return NULL; 1632} 1633 1634/* 1635 * Unregister hstate attributes from a single node sysdev. 1636 * No-op if no hstate attributes attached. 1637 */ 1638void hugetlb_unregister_node(struct node *node) 1639{ 1640 struct hstate *h; 1641 struct node_hstate *nhs = &node_hstates[node->sysdev.id]; 1642 1643 if (!nhs->hugepages_kobj) 1644 return; /* no hstate attributes */ 1645 1646 for_each_hstate(h) 1647 if (nhs->hstate_kobjs[h - hstates]) { 1648 kobject_put(nhs->hstate_kobjs[h - hstates]); 1649 nhs->hstate_kobjs[h - hstates] = NULL; 1650 } 1651 1652 kobject_put(nhs->hugepages_kobj); 1653 nhs->hugepages_kobj = NULL; 1654} 1655 1656/* 1657 * hugetlb module exit: unregister hstate attributes from node sysdevs 1658 * that have them. 1659 */ 1660static void hugetlb_unregister_all_nodes(void) 1661{ 1662 int nid; 1663 1664 /* 1665 * disable node sysdev registrations. 1666 */ 1667 register_hugetlbfs_with_node(NULL, NULL); 1668 1669 /* 1670 * remove hstate attributes from any nodes that have them. 1671 */ 1672 for (nid = 0; nid < nr_node_ids; nid++) 1673 hugetlb_unregister_node(&node_devices[nid]); 1674} 1675 1676/* 1677 * Register hstate attributes for a single node sysdev. 1678 * No-op if attributes already registered. 1679 */ 1680void hugetlb_register_node(struct node *node) 1681{ 1682 struct hstate *h; 1683 struct node_hstate *nhs = &node_hstates[node->sysdev.id]; 1684 int err; 1685 1686 if (nhs->hugepages_kobj) 1687 return; /* already allocated */ 1688 1689 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1690 &node->sysdev.kobj); 1691 if (!nhs->hugepages_kobj) 1692 return; 1693 1694 for_each_hstate(h) { 1695 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1696 nhs->hstate_kobjs, 1697 &per_node_hstate_attr_group); 1698 if (err) { 1699 printk(KERN_ERR "Hugetlb: Unable to add hstate %s" 1700 " for node %d\n", 1701 h->name, node->sysdev.id); 1702 hugetlb_unregister_node(node); 1703 break; 1704 } 1705 } 1706} 1707 1708/* 1709 * hugetlb init time: register hstate attributes for all registered node 1710 * sysdevs of nodes that have memory. All on-line nodes should have 1711 * registered their associated sysdev by this time. 1712 */ 1713static void hugetlb_register_all_nodes(void) 1714{ 1715 int nid; 1716 1717 for_each_node_state(nid, N_HIGH_MEMORY) { 1718 struct node *node = &node_devices[nid]; 1719 if (node->sysdev.id == nid) 1720 hugetlb_register_node(node); 1721 } 1722 1723 /* 1724 * Let the node sysdev driver know we're here so it can 1725 * [un]register hstate attributes on node hotplug. 1726 */ 1727 register_hugetlbfs_with_node(hugetlb_register_node, 1728 hugetlb_unregister_node); 1729} 1730#else /* !CONFIG_NUMA */ 1731 1732static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1733{ 1734 BUG(); 1735 if (nidp) 1736 *nidp = -1; 1737 return NULL; 1738} 1739 1740static void hugetlb_unregister_all_nodes(void) { } 1741 1742static void hugetlb_register_all_nodes(void) { } 1743 1744#endif 1745 1746static void __exit hugetlb_exit(void) 1747{ 1748 struct hstate *h; 1749 1750 hugetlb_unregister_all_nodes(); 1751 1752 for_each_hstate(h) { 1753 kobject_put(hstate_kobjs[h - hstates]); 1754 } 1755 1756 kobject_put(hugepages_kobj); 1757} 1758module_exit(hugetlb_exit); 1759 1760static int __init hugetlb_init(void) 1761{ 1762 /* Some platform decide whether they support huge pages at boot 1763 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1764 * there is no such support 1765 */ 1766 if (HPAGE_SHIFT == 0) 1767 return 0; 1768 1769 if (!size_to_hstate(default_hstate_size)) { 1770 default_hstate_size = HPAGE_SIZE; 1771 if (!size_to_hstate(default_hstate_size)) 1772 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1773 } 1774 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; 1775 if (default_hstate_max_huge_pages) 1776 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1777 1778 hugetlb_init_hstates(); 1779 1780 gather_bootmem_prealloc(); 1781 1782 report_hugepages(); 1783 1784 hugetlb_sysfs_init(); 1785 1786 hugetlb_register_all_nodes(); 1787 1788 return 0; 1789} 1790module_init(hugetlb_init); 1791 1792/* Should be called on processing a hugepagesz=... option */ 1793void __init hugetlb_add_hstate(unsigned order) 1794{ 1795 struct hstate *h; 1796 unsigned long i; 1797 1798 if (size_to_hstate(PAGE_SIZE << order)) { 1799 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1800 return; 1801 } 1802 BUG_ON(max_hstate >= HUGE_MAX_HSTATE); 1803 BUG_ON(order == 0); 1804 h = &hstates[max_hstate++]; 1805 h->order = order; 1806 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1807 h->nr_huge_pages = 0; 1808 h->free_huge_pages = 0; 1809 for (i = 0; i < MAX_NUMNODES; ++i) 1810 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1811 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]); 1812 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]); 1813 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1814 huge_page_size(h)/1024); 1815 1816 parsed_hstate = h; 1817} 1818 1819static int __init hugetlb_nrpages_setup(char *s) 1820{ 1821 unsigned long *mhp; 1822 static unsigned long *last_mhp; 1823 1824 /* 1825 * !max_hstate means we haven't parsed a hugepagesz= parameter yet, 1826 * so this hugepages= parameter goes to the "default hstate". 1827 */ 1828 if (!max_hstate) 1829 mhp = &default_hstate_max_huge_pages; 1830 else 1831 mhp = &parsed_hstate->max_huge_pages; 1832 1833 if (mhp == last_mhp) { 1834 printk(KERN_WARNING "hugepages= specified twice without " 1835 "interleaving hugepagesz=, ignoring\n"); 1836 return 1; 1837 } 1838 1839 if (sscanf(s, "%lu", mhp) <= 0) 1840 *mhp = 0; 1841 1842 /* 1843 * Global state is always initialized later in hugetlb_init. 1844 * But we need to allocate >= MAX_ORDER hstates here early to still 1845 * use the bootmem allocator. 1846 */ 1847 if (max_hstate && parsed_hstate->order >= MAX_ORDER) 1848 hugetlb_hstate_alloc_pages(parsed_hstate); 1849 1850 last_mhp = mhp; 1851 1852 return 1; 1853} 1854__setup("hugepages=", hugetlb_nrpages_setup); 1855 1856static int __init hugetlb_default_setup(char *s) 1857{ 1858 default_hstate_size = memparse(s, &s); 1859 return 1; 1860} 1861__setup("default_hugepagesz=", hugetlb_default_setup); 1862 1863static unsigned int cpuset_mems_nr(unsigned int *array) 1864{ 1865 int node; 1866 unsigned int nr = 0; 1867 1868 for_each_node_mask(node, cpuset_current_mems_allowed) 1869 nr += array[node]; 1870 1871 return nr; 1872} 1873 1874#ifdef CONFIG_SYSCTL 1875static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 1876 struct ctl_table *table, int write, 1877 void __user *buffer, size_t *length, loff_t *ppos) 1878{ 1879 struct hstate *h = &default_hstate; 1880 unsigned long tmp; 1881 int ret; 1882 1883 tmp = h->max_huge_pages; 1884 1885 if (write && h->order >= MAX_ORDER) 1886 return -EINVAL; 1887 1888 table->data = &tmp; 1889 table->maxlen = sizeof(unsigned long); 1890 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 1891 if (ret) 1892 goto out; 1893 1894 if (write) { 1895 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 1896 GFP_KERNEL | __GFP_NORETRY); 1897 if (!(obey_mempolicy && 1898 init_nodemask_of_mempolicy(nodes_allowed))) { 1899 NODEMASK_FREE(nodes_allowed); 1900 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1901 } 1902 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 1903 1904 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1905 NODEMASK_FREE(nodes_allowed); 1906 } 1907out: 1908 return ret; 1909} 1910 1911int hugetlb_sysctl_handler(struct ctl_table *table, int write, 1912 void __user *buffer, size_t *length, loff_t *ppos) 1913{ 1914 1915 return hugetlb_sysctl_handler_common(false, table, write, 1916 buffer, length, ppos); 1917} 1918 1919#ifdef CONFIG_NUMA 1920int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 1921 void __user *buffer, size_t *length, loff_t *ppos) 1922{ 1923 return hugetlb_sysctl_handler_common(true, table, write, 1924 buffer, length, ppos); 1925} 1926#endif /* CONFIG_NUMA */ 1927 1928int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 1929 void __user *buffer, 1930 size_t *length, loff_t *ppos) 1931{ 1932 proc_dointvec(table, write, buffer, length, ppos); 1933 if (hugepages_treat_as_movable) 1934 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 1935 else 1936 htlb_alloc_mask = GFP_HIGHUSER; 1937 return 0; 1938} 1939 1940int hugetlb_overcommit_handler(struct ctl_table *table, int write, 1941 void __user *buffer, 1942 size_t *length, loff_t *ppos) 1943{ 1944 struct hstate *h = &default_hstate; 1945 unsigned long tmp; 1946 int ret; 1947 1948 tmp = h->nr_overcommit_huge_pages; 1949 1950 if (write && h->order >= MAX_ORDER) 1951 return -EINVAL; 1952 1953 table->data = &tmp; 1954 table->maxlen = sizeof(unsigned long); 1955 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 1956 if (ret) 1957 goto out; 1958 1959 if (write) { 1960 spin_lock(&hugetlb_lock); 1961 h->nr_overcommit_huge_pages = tmp; 1962 spin_unlock(&hugetlb_lock); 1963 } 1964out: 1965 return ret; 1966} 1967 1968#endif /* CONFIG_SYSCTL */ 1969 1970void hugetlb_report_meminfo(struct seq_file *m) 1971{ 1972 struct hstate *h = &default_hstate; 1973 seq_printf(m, 1974 "HugePages_Total: %5lu\n" 1975 "HugePages_Free: %5lu\n" 1976 "HugePages_Rsvd: %5lu\n" 1977 "HugePages_Surp: %5lu\n" 1978 "Hugepagesize: %8lu kB\n", 1979 h->nr_huge_pages, 1980 h->free_huge_pages, 1981 h->resv_huge_pages, 1982 h->surplus_huge_pages, 1983 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 1984} 1985 1986int hugetlb_report_node_meminfo(int nid, char *buf) 1987{ 1988 struct hstate *h = &default_hstate; 1989 return sprintf(buf, 1990 "Node %d HugePages_Total: %5u\n" 1991 "Node %d HugePages_Free: %5u\n" 1992 "Node %d HugePages_Surp: %5u\n", 1993 nid, h->nr_huge_pages_node[nid], 1994 nid, h->free_huge_pages_node[nid], 1995 nid, h->surplus_huge_pages_node[nid]); 1996} 1997 1998/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 1999unsigned long hugetlb_total_pages(void) 2000{ 2001 struct hstate *h = &default_hstate; 2002 return h->nr_huge_pages * pages_per_huge_page(h); 2003} 2004 2005static int hugetlb_acct_memory(struct hstate *h, long delta) 2006{ 2007 int ret = -ENOMEM; 2008 2009 spin_lock(&hugetlb_lock); 2010 /* 2011 * When cpuset is configured, it breaks the strict hugetlb page 2012 * reservation as the accounting is done on a global variable. Such 2013 * reservation is completely rubbish in the presence of cpuset because 2014 * the reservation is not checked against page availability for the 2015 * current cpuset. Application can still potentially OOM'ed by kernel 2016 * with lack of free htlb page in cpuset that the task is in. 2017 * Attempt to enforce strict accounting with cpuset is almost 2018 * impossible (or too ugly) because cpuset is too fluid that 2019 * task or memory node can be dynamically moved between cpusets. 2020 * 2021 * The change of semantics for shared hugetlb mapping with cpuset is 2022 * undesirable. However, in order to preserve some of the semantics, 2023 * we fall back to check against current free page availability as 2024 * a best attempt and hopefully to minimize the impact of changing 2025 * semantics that cpuset has. 2026 */ 2027 if (delta > 0) { 2028 if (gather_surplus_pages(h, delta) < 0) 2029 goto out; 2030 2031 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 2032 return_unused_surplus_pages(h, delta); 2033 goto out; 2034 } 2035 } 2036 2037 ret = 0; 2038 if (delta < 0) 2039 return_unused_surplus_pages(h, (unsigned long) -delta); 2040 2041out: 2042 spin_unlock(&hugetlb_lock); 2043 return ret; 2044} 2045 2046static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2047{ 2048 struct resv_map *reservations = vma_resv_map(vma); 2049 2050 /* 2051 * This new VMA should share its siblings reservation map if present. 2052 * The VMA will only ever have a valid reservation map pointer where 2053 * it is being copied for another still existing VMA. As that VMA 2054 * has a reference to the reservation map it cannot disappear until 2055 * after this open call completes. It is therefore safe to take a 2056 * new reference here without additional locking. 2057 */ 2058 if (reservations) 2059 kref_get(&reservations->refs); 2060} 2061 2062static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2063{ 2064 struct hstate *h = hstate_vma(vma); 2065 struct resv_map *reservations = vma_resv_map(vma); 2066 unsigned long reserve; 2067 unsigned long start; 2068 unsigned long end; 2069 2070 if (reservations) { 2071 start = vma_hugecache_offset(h, vma, vma->vm_start); 2072 end = vma_hugecache_offset(h, vma, vma->vm_end); 2073 2074 reserve = (end - start) - 2075 region_count(&reservations->regions, start, end); 2076 2077 kref_put(&reservations->refs, resv_map_release); 2078 2079 if (reserve) { 2080 hugetlb_acct_memory(h, -reserve); 2081 hugetlb_put_quota(vma->vm_file->f_mapping, reserve); 2082 } 2083 } 2084} 2085 2086/* 2087 * We cannot handle pagefaults against hugetlb pages at all. They cause 2088 * handle_mm_fault() to try to instantiate regular-sized pages in the 2089 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2090 * this far. 2091 */ 2092static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2093{ 2094 BUG(); 2095 return 0; 2096} 2097 2098const struct vm_operations_struct hugetlb_vm_ops = { 2099 .fault = hugetlb_vm_op_fault, 2100 .open = hugetlb_vm_op_open, 2101 .close = hugetlb_vm_op_close, 2102}; 2103 2104static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2105 int writable) 2106{ 2107 pte_t entry; 2108 2109 if (writable) { 2110 entry = 2111 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 2112 } else { 2113 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 2114 } 2115 entry = pte_mkyoung(entry); 2116 entry = pte_mkhuge(entry); 2117 2118 return entry; 2119} 2120 2121static void set_huge_ptep_writable(struct vm_area_struct *vma, 2122 unsigned long address, pte_t *ptep) 2123{ 2124 pte_t entry; 2125 2126 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 2127 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { 2128 update_mmu_cache(vma, address, ptep); 2129 } 2130} 2131 2132 2133int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2134 struct vm_area_struct *vma) 2135{ 2136 pte_t *src_pte, *dst_pte, entry; 2137 struct page *ptepage; 2138 unsigned long addr; 2139 int cow; 2140 struct hstate *h = hstate_vma(vma); 2141 unsigned long sz = huge_page_size(h); 2142 2143 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2144 2145 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2146 src_pte = huge_pte_offset(src, addr); 2147 if (!src_pte) 2148 continue; 2149 dst_pte = huge_pte_alloc(dst, addr, sz); 2150 if (!dst_pte) 2151 goto nomem; 2152 2153 /* If the pagetables are shared don't copy or take references */ 2154 if (dst_pte == src_pte) 2155 continue; 2156 2157 spin_lock(&dst->page_table_lock); 2158 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 2159 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2160 if (cow) 2161 huge_ptep_set_wrprotect(src, addr, src_pte); 2162 entry = huge_ptep_get(src_pte); 2163 ptepage = pte_page(entry); 2164 get_page(ptepage); 2165 page_dup_rmap(ptepage); 2166 set_huge_pte_at(dst, addr, dst_pte, entry); 2167 } 2168 spin_unlock(&src->page_table_lock); 2169 spin_unlock(&dst->page_table_lock); 2170 } 2171 return 0; 2172 2173nomem: 2174 return -ENOMEM; 2175} 2176 2177static int is_hugetlb_entry_migration(pte_t pte) 2178{ 2179 swp_entry_t swp; 2180 2181 if (huge_pte_none(pte) || pte_present(pte)) 2182 return 0; 2183 swp = pte_to_swp_entry(pte); 2184 if (non_swap_entry(swp) && is_migration_entry(swp)) { 2185 return 1; 2186 } else 2187 return 0; 2188} 2189 2190static int is_hugetlb_entry_hwpoisoned(pte_t pte) 2191{ 2192 swp_entry_t swp; 2193 2194 if (huge_pte_none(pte) || pte_present(pte)) 2195 return 0; 2196 swp = pte_to_swp_entry(pte); 2197 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) { 2198 return 1; 2199 } else 2200 return 0; 2201} 2202 2203void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2204 unsigned long end, struct page *ref_page) 2205{ 2206 struct mm_struct *mm = vma->vm_mm; 2207 unsigned long address; 2208 pte_t *ptep; 2209 pte_t pte; 2210 struct page *page; 2211 struct page *tmp; 2212 struct hstate *h = hstate_vma(vma); 2213 unsigned long sz = huge_page_size(h); 2214 2215 /* 2216 * A page gathering list, protected by per file i_mmap_mutex. The 2217 * lock is used to avoid list corruption from multiple unmapping 2218 * of the same page since we are using page->lru. 2219 */ 2220 LIST_HEAD(page_list); 2221 2222 WARN_ON(!is_vm_hugetlb_page(vma)); 2223 BUG_ON(start & ~huge_page_mask(h)); 2224 BUG_ON(end & ~huge_page_mask(h)); 2225 2226 mmu_notifier_invalidate_range_start(mm, start, end); 2227 spin_lock(&mm->page_table_lock); 2228 for (address = start; address < end; address += sz) { 2229 ptep = huge_pte_offset(mm, address); 2230 if (!ptep) 2231 continue; 2232 2233 if (huge_pmd_unshare(mm, &address, ptep)) 2234 continue; 2235 2236 /* 2237 * If a reference page is supplied, it is because a specific 2238 * page is being unmapped, not a range. Ensure the page we 2239 * are about to unmap is the actual page of interest. 2240 */ 2241 if (ref_page) { 2242 pte = huge_ptep_get(ptep); 2243 if (huge_pte_none(pte)) 2244 continue; 2245 page = pte_page(pte); 2246 if (page != ref_page) 2247 continue; 2248 2249 /* 2250 * Mark the VMA as having unmapped its page so that 2251 * future faults in this VMA will fail rather than 2252 * looking like data was lost 2253 */ 2254 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2255 } 2256 2257 pte = huge_ptep_get_and_clear(mm, address, ptep); 2258 if (huge_pte_none(pte)) 2259 continue; 2260 2261 /* 2262 * HWPoisoned hugepage is already unmapped and dropped reference 2263 */ 2264 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) 2265 continue; 2266 2267 page = pte_page(pte); 2268 if (pte_dirty(pte)) 2269 set_page_dirty(page); 2270 list_add(&page->lru, &page_list); 2271 } 2272 spin_unlock(&mm->page_table_lock); 2273 flush_tlb_range(vma, start, end); 2274 mmu_notifier_invalidate_range_end(mm, start, end); 2275 list_for_each_entry_safe(page, tmp, &page_list, lru) { 2276 page_remove_rmap(page); 2277 list_del(&page->lru); 2278 put_page(page); 2279 } 2280} 2281 2282void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2283 unsigned long end, struct page *ref_page) 2284{ 2285 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 2286 __unmap_hugepage_range(vma, start, end, ref_page); 2287 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 2288} 2289 2290/* 2291 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2292 * mappping it owns the reserve page for. The intention is to unmap the page 2293 * from other VMAs and let the children be SIGKILLed if they are faulting the 2294 * same region. 2295 */ 2296static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2297 struct page *page, unsigned long address) 2298{ 2299 struct hstate *h = hstate_vma(vma); 2300 struct vm_area_struct *iter_vma; 2301 struct address_space *mapping; 2302 struct prio_tree_iter iter; 2303 pgoff_t pgoff; 2304 2305 /* 2306 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2307 * from page cache lookup which is in HPAGE_SIZE units. 2308 */ 2309 address = address & huge_page_mask(h); 2310 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) 2311 + (vma->vm_pgoff >> PAGE_SHIFT); 2312 mapping = (struct address_space *)page_private(page); 2313 2314 /* 2315 * Take the mapping lock for the duration of the table walk. As 2316 * this mapping should be shared between all the VMAs, 2317 * __unmap_hugepage_range() is called as the lock is already held 2318 */ 2319 mutex_lock(&mapping->i_mmap_mutex); 2320 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { 2321 /* Do not unmap the current VMA */ 2322 if (iter_vma == vma) 2323 continue; 2324 2325 /* 2326 * Unmap the page from other VMAs without their own reserves. 2327 * They get marked to be SIGKILLed if they fault in these 2328 * areas. This is because a future no-page fault on this VMA 2329 * could insert a zeroed page instead of the data existing 2330 * from the time of fork. This would look like data corruption 2331 */ 2332 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2333 __unmap_hugepage_range(iter_vma, 2334 address, address + huge_page_size(h), 2335 page); 2336 } 2337 mutex_unlock(&mapping->i_mmap_mutex); 2338 2339 return 1; 2340} 2341 2342/* 2343 * Hugetlb_cow() should be called with page lock of the original hugepage held. 2344 */ 2345static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2346 unsigned long address, pte_t *ptep, pte_t pte, 2347 struct page *pagecache_page) 2348{ 2349 struct hstate *h = hstate_vma(vma); 2350 struct page *old_page, *new_page; 2351 int avoidcopy; 2352 int outside_reserve = 0; 2353 2354 old_page = pte_page(pte); 2355 2356retry_avoidcopy: 2357 /* If no-one else is actually using this page, avoid the copy 2358 * and just make the page writable */ 2359 avoidcopy = (page_mapcount(old_page) == 1); 2360 if (avoidcopy) { 2361 if (PageAnon(old_page)) 2362 page_move_anon_rmap(old_page, vma, address); 2363 set_huge_ptep_writable(vma, address, ptep); 2364 return 0; 2365 } 2366 2367 /* 2368 * If the process that created a MAP_PRIVATE mapping is about to 2369 * perform a COW due to a shared page count, attempt to satisfy 2370 * the allocation without using the existing reserves. The pagecache 2371 * page is used to determine if the reserve at this address was 2372 * consumed or not. If reserves were used, a partial faulted mapping 2373 * at the time of fork() could consume its reserves on COW instead 2374 * of the full address range. 2375 */ 2376 if (!(vma->vm_flags & VM_MAYSHARE) && 2377 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2378 old_page != pagecache_page) 2379 outside_reserve = 1; 2380 2381 page_cache_get(old_page); 2382 2383 /* Drop page_table_lock as buddy allocator may be called */ 2384 spin_unlock(&mm->page_table_lock); 2385 new_page = alloc_huge_page(vma, address, outside_reserve); 2386 2387 if (IS_ERR(new_page)) { 2388 page_cache_release(old_page); 2389 2390 /* 2391 * If a process owning a MAP_PRIVATE mapping fails to COW, 2392 * it is due to references held by a child and an insufficient 2393 * huge page pool. To guarantee the original mappers 2394 * reliability, unmap the page from child processes. The child 2395 * may get SIGKILLed if it later faults. 2396 */ 2397 if (outside_reserve) { 2398 BUG_ON(huge_pte_none(pte)); 2399 if (unmap_ref_private(mm, vma, old_page, address)) { 2400 BUG_ON(page_count(old_page) != 1); 2401 BUG_ON(huge_pte_none(pte)); 2402 spin_lock(&mm->page_table_lock); 2403 goto retry_avoidcopy; 2404 } 2405 WARN_ON_ONCE(1); 2406 } 2407 2408 /* Caller expects lock to be held */ 2409 spin_lock(&mm->page_table_lock); 2410 return -PTR_ERR(new_page); 2411 } 2412 2413 /* 2414 * When the original hugepage is shared one, it does not have 2415 * anon_vma prepared. 2416 */ 2417 if (unlikely(anon_vma_prepare(vma))) { 2418 /* Caller expects lock to be held */ 2419 spin_lock(&mm->page_table_lock); 2420 return VM_FAULT_OOM; 2421 } 2422 2423 copy_user_huge_page(new_page, old_page, address, vma, 2424 pages_per_huge_page(h)); 2425 __SetPageUptodate(new_page); 2426 2427 /* 2428 * Retake the page_table_lock to check for racing updates 2429 * before the page tables are altered 2430 */ 2431 spin_lock(&mm->page_table_lock); 2432 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2433 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2434 /* Break COW */ 2435 mmu_notifier_invalidate_range_start(mm, 2436 address & huge_page_mask(h), 2437 (address & huge_page_mask(h)) + huge_page_size(h)); 2438 huge_ptep_clear_flush(vma, address, ptep); 2439 set_huge_pte_at(mm, address, ptep, 2440 make_huge_pte(vma, new_page, 1)); 2441 page_remove_rmap(old_page); 2442 hugepage_add_new_anon_rmap(new_page, vma, address); 2443 /* Make the old page be freed below */ 2444 new_page = old_page; 2445 mmu_notifier_invalidate_range_end(mm, 2446 address & huge_page_mask(h), 2447 (address & huge_page_mask(h)) + huge_page_size(h)); 2448 } 2449 page_cache_release(new_page); 2450 page_cache_release(old_page); 2451 return 0; 2452} 2453 2454/* Return the pagecache page at a given address within a VMA */ 2455static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2456 struct vm_area_struct *vma, unsigned long address) 2457{ 2458 struct address_space *mapping; 2459 pgoff_t idx; 2460 2461 mapping = vma->vm_file->f_mapping; 2462 idx = vma_hugecache_offset(h, vma, address); 2463 2464 return find_lock_page(mapping, idx); 2465} 2466 2467/* 2468 * Return whether there is a pagecache page to back given address within VMA. 2469 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2470 */ 2471static bool hugetlbfs_pagecache_present(struct hstate *h, 2472 struct vm_area_struct *vma, unsigned long address) 2473{ 2474 struct address_space *mapping; 2475 pgoff_t idx; 2476 struct page *page; 2477 2478 mapping = vma->vm_file->f_mapping; 2479 idx = vma_hugecache_offset(h, vma, address); 2480 2481 page = find_get_page(mapping, idx); 2482 if (page) 2483 put_page(page); 2484 return page != NULL; 2485} 2486 2487static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2488 unsigned long address, pte_t *ptep, unsigned int flags) 2489{ 2490 struct hstate *h = hstate_vma(vma); 2491 int ret = VM_FAULT_SIGBUS; 2492 pgoff_t idx; 2493 unsigned long size; 2494 struct page *page; 2495 struct address_space *mapping; 2496 pte_t new_pte; 2497 2498 /* 2499 * Currently, we are forced to kill the process in the event the 2500 * original mapper has unmapped pages from the child due to a failed 2501 * COW. Warn that such a situation has occurred as it may not be obvious 2502 */ 2503 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2504 printk(KERN_WARNING 2505 "PID %d killed due to inadequate hugepage pool\n", 2506 current->pid); 2507 return ret; 2508 } 2509 2510 mapping = vma->vm_file->f_mapping; 2511 idx = vma_hugecache_offset(h, vma, address); 2512 2513 /* 2514 * Use page lock to guard against racing truncation 2515 * before we get page_table_lock. 2516 */ 2517retry: 2518 page = find_lock_page(mapping, idx); 2519 if (!page) { 2520 size = i_size_read(mapping->host) >> huge_page_shift(h); 2521 if (idx >= size) 2522 goto out; 2523 page = alloc_huge_page(vma, address, 0); 2524 if (IS_ERR(page)) { 2525 ret = -PTR_ERR(page); 2526 goto out; 2527 } 2528 clear_huge_page(page, address, pages_per_huge_page(h)); 2529 __SetPageUptodate(page); 2530 2531 if (vma->vm_flags & VM_MAYSHARE) { 2532 int err; 2533 struct inode *inode = mapping->host; 2534 2535 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2536 if (err) { 2537 put_page(page); 2538 if (err == -EEXIST) 2539 goto retry; 2540 goto out; 2541 } 2542 2543 spin_lock(&inode->i_lock); 2544 inode->i_blocks += blocks_per_huge_page(h); 2545 spin_unlock(&inode->i_lock); 2546 page_dup_rmap(page); 2547 } else { 2548 lock_page(page); 2549 if (unlikely(anon_vma_prepare(vma))) { 2550 ret = VM_FAULT_OOM; 2551 goto backout_unlocked; 2552 } 2553 hugepage_add_new_anon_rmap(page, vma, address); 2554 } 2555 } else { 2556 /* 2557 * If memory error occurs between mmap() and fault, some process 2558 * don't have hwpoisoned swap entry for errored virtual address. 2559 * So we need to block hugepage fault by PG_hwpoison bit check. 2560 */ 2561 if (unlikely(PageHWPoison(page))) { 2562 ret = VM_FAULT_HWPOISON | 2563 VM_FAULT_SET_HINDEX(h - hstates); 2564 goto backout_unlocked; 2565 } 2566 page_dup_rmap(page); 2567 } 2568 2569 /* 2570 * If we are going to COW a private mapping later, we examine the 2571 * pending reservations for this page now. This will ensure that 2572 * any allocations necessary to record that reservation occur outside 2573 * the spinlock. 2574 */ 2575 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2576 if (vma_needs_reservation(h, vma, address) < 0) { 2577 ret = VM_FAULT_OOM; 2578 goto backout_unlocked; 2579 } 2580 2581 spin_lock(&mm->page_table_lock); 2582 size = i_size_read(mapping->host) >> huge_page_shift(h); 2583 if (idx >= size) 2584 goto backout; 2585 2586 ret = 0; 2587 if (!huge_pte_none(huge_ptep_get(ptep))) 2588 goto backout; 2589 2590 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2591 && (vma->vm_flags & VM_SHARED))); 2592 set_huge_pte_at(mm, address, ptep, new_pte); 2593 2594 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2595 /* Optimization, do the COW without a second fault */ 2596 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2597 } 2598 2599 spin_unlock(&mm->page_table_lock); 2600 unlock_page(page); 2601out: 2602 return ret; 2603 2604backout: 2605 spin_unlock(&mm->page_table_lock); 2606backout_unlocked: 2607 unlock_page(page); 2608 put_page(page); 2609 goto out; 2610} 2611 2612int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2613 unsigned long address, unsigned int flags) 2614{ 2615 pte_t *ptep; 2616 pte_t entry; 2617 int ret; 2618 struct page *page = NULL; 2619 struct page *pagecache_page = NULL; 2620 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2621 struct hstate *h = hstate_vma(vma); 2622 2623 ptep = huge_pte_offset(mm, address); 2624 if (ptep) { 2625 entry = huge_ptep_get(ptep); 2626 if (unlikely(is_hugetlb_entry_migration(entry))) { 2627 migration_entry_wait(mm, (pmd_t *)ptep, address); 2628 return 0; 2629 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) 2630 return VM_FAULT_HWPOISON_LARGE | 2631 VM_FAULT_SET_HINDEX(h - hstates); 2632 } 2633 2634 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2635 if (!ptep) 2636 return VM_FAULT_OOM; 2637 2638 /* 2639 * Serialize hugepage allocation and instantiation, so that we don't 2640 * get spurious allocation failures if two CPUs race to instantiate 2641 * the same page in the page cache. 2642 */ 2643 mutex_lock(&hugetlb_instantiation_mutex); 2644 entry = huge_ptep_get(ptep); 2645 if (huge_pte_none(entry)) { 2646 ret = hugetlb_no_page(mm, vma, address, ptep, flags); 2647 goto out_mutex; 2648 } 2649 2650 ret = 0; 2651 2652 /* 2653 * If we are going to COW the mapping later, we examine the pending 2654 * reservations for this page now. This will ensure that any 2655 * allocations necessary to record that reservation occur outside the 2656 * spinlock. For private mappings, we also lookup the pagecache 2657 * page now as it is used to determine if a reservation has been 2658 * consumed. 2659 */ 2660 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) { 2661 if (vma_needs_reservation(h, vma, address) < 0) { 2662 ret = VM_FAULT_OOM; 2663 goto out_mutex; 2664 } 2665 2666 if (!(vma->vm_flags & VM_MAYSHARE)) 2667 pagecache_page = hugetlbfs_pagecache_page(h, 2668 vma, address); 2669 } 2670 2671 /* 2672 * hugetlb_cow() requires page locks of pte_page(entry) and 2673 * pagecache_page, so here we need take the former one 2674 * when page != pagecache_page or !pagecache_page. 2675 * Note that locking order is always pagecache_page -> page, 2676 * so no worry about deadlock. 2677 */ 2678 page = pte_page(entry); 2679 if (page != pagecache_page) 2680 lock_page(page); 2681 2682 spin_lock(&mm->page_table_lock); 2683 /* Check for a racing update before calling hugetlb_cow */ 2684 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2685 goto out_page_table_lock; 2686 2687 2688 if (flags & FAULT_FLAG_WRITE) { 2689 if (!pte_write(entry)) { 2690 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2691 pagecache_page); 2692 goto out_page_table_lock; 2693 } 2694 entry = pte_mkdirty(entry); 2695 } 2696 entry = pte_mkyoung(entry); 2697 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 2698 flags & FAULT_FLAG_WRITE)) 2699 update_mmu_cache(vma, address, ptep); 2700 2701out_page_table_lock: 2702 spin_unlock(&mm->page_table_lock); 2703 2704 if (pagecache_page) { 2705 unlock_page(pagecache_page); 2706 put_page(pagecache_page); 2707 } 2708 if (page != pagecache_page) 2709 unlock_page(page); 2710 2711out_mutex: 2712 mutex_unlock(&hugetlb_instantiation_mutex); 2713 2714 return ret; 2715} 2716 2717/* Can be overriden by architectures */ 2718__attribute__((weak)) struct page * 2719follow_huge_pud(struct mm_struct *mm, unsigned long address, 2720 pud_t *pud, int write) 2721{ 2722 BUG(); 2723 return NULL; 2724} 2725 2726int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2727 struct page **pages, struct vm_area_struct **vmas, 2728 unsigned long *position, int *length, int i, 2729 unsigned int flags) 2730{ 2731 unsigned long pfn_offset; 2732 unsigned long vaddr = *position; 2733 int remainder = *length; 2734 struct hstate *h = hstate_vma(vma); 2735 2736 spin_lock(&mm->page_table_lock); 2737 while (vaddr < vma->vm_end && remainder) { 2738 pte_t *pte; 2739 int absent; 2740 struct page *page; 2741 2742 /* 2743 * Some archs (sparc64, sh*) have multiple pte_ts to 2744 * each hugepage. We have to make sure we get the 2745 * first, for the page indexing below to work. 2746 */ 2747 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2748 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 2749 2750 /* 2751 * When coredumping, it suits get_dump_page if we just return 2752 * an error where there's an empty slot with no huge pagecache 2753 * to back it. This way, we avoid allocating a hugepage, and 2754 * the sparse dumpfile avoids allocating disk blocks, but its 2755 * huge holes still show up with zeroes where they need to be. 2756 */ 2757 if (absent && (flags & FOLL_DUMP) && 2758 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 2759 remainder = 0; 2760 break; 2761 } 2762 2763 if (absent || 2764 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) { 2765 int ret; 2766 2767 spin_unlock(&mm->page_table_lock); 2768 ret = hugetlb_fault(mm, vma, vaddr, 2769 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 2770 spin_lock(&mm->page_table_lock); 2771 if (!(ret & VM_FAULT_ERROR)) 2772 continue; 2773 2774 remainder = 0; 2775 break; 2776 } 2777 2778 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2779 page = pte_page(huge_ptep_get(pte)); 2780same_page: 2781 if (pages) { 2782 pages[i] = mem_map_offset(page, pfn_offset); 2783 get_page(pages[i]); 2784 } 2785 2786 if (vmas) 2787 vmas[i] = vma; 2788 2789 vaddr += PAGE_SIZE; 2790 ++pfn_offset; 2791 --remainder; 2792 ++i; 2793 if (vaddr < vma->vm_end && remainder && 2794 pfn_offset < pages_per_huge_page(h)) { 2795 /* 2796 * We use pfn_offset to avoid touching the pageframes 2797 * of this compound page. 2798 */ 2799 goto same_page; 2800 } 2801 } 2802 spin_unlock(&mm->page_table_lock); 2803 *length = remainder; 2804 *position = vaddr; 2805 2806 return i ? i : -EFAULT; 2807} 2808 2809void hugetlb_change_protection(struct vm_area_struct *vma, 2810 unsigned long address, unsigned long end, pgprot_t newprot) 2811{ 2812 struct mm_struct *mm = vma->vm_mm; 2813 unsigned long start = address; 2814 pte_t *ptep; 2815 pte_t pte; 2816 struct hstate *h = hstate_vma(vma); 2817 2818 BUG_ON(address >= end); 2819 flush_cache_range(vma, address, end); 2820 2821 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 2822 spin_lock(&mm->page_table_lock); 2823 for (; address < end; address += huge_page_size(h)) { 2824 ptep = huge_pte_offset(mm, address); 2825 if (!ptep) 2826 continue; 2827 if (huge_pmd_unshare(mm, &address, ptep)) 2828 continue; 2829 if (!huge_pte_none(huge_ptep_get(ptep))) { 2830 pte = huge_ptep_get_and_clear(mm, address, ptep); 2831 pte = pte_mkhuge(pte_modify(pte, newprot)); 2832 set_huge_pte_at(mm, address, ptep, pte); 2833 } 2834 } 2835 spin_unlock(&mm->page_table_lock); 2836 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 2837 2838 flush_tlb_range(vma, start, end); 2839} 2840 2841int hugetlb_reserve_pages(struct inode *inode, 2842 long from, long to, 2843 struct vm_area_struct *vma, 2844 vm_flags_t vm_flags) 2845{ 2846 long ret, chg; 2847 struct hstate *h = hstate_inode(inode); 2848 2849 /* 2850 * Only apply hugepage reservation if asked. At fault time, an 2851 * attempt will be made for VM_NORESERVE to allocate a page 2852 * and filesystem quota without using reserves 2853 */ 2854 if (vm_flags & VM_NORESERVE) 2855 return 0; 2856 2857 /* 2858 * Shared mappings base their reservation on the number of pages that 2859 * are already allocated on behalf of the file. Private mappings need 2860 * to reserve the full area even if read-only as mprotect() may be 2861 * called to make the mapping read-write. Assume !vma is a shm mapping 2862 */ 2863 if (!vma || vma->vm_flags & VM_MAYSHARE) 2864 chg = region_chg(&inode->i_mapping->private_list, from, to); 2865 else { 2866 struct resv_map *resv_map = resv_map_alloc(); 2867 if (!resv_map) 2868 return -ENOMEM; 2869 2870 chg = to - from; 2871 2872 set_vma_resv_map(vma, resv_map); 2873 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 2874 } 2875 2876 if (chg < 0) 2877 return chg; 2878 2879 /* There must be enough filesystem quota for the mapping */ 2880 if (hugetlb_get_quota(inode->i_mapping, chg)) 2881 return -ENOSPC; 2882 2883 /* 2884 * Check enough hugepages are available for the reservation. 2885 * Hand back the quota if there are not 2886 */ 2887 ret = hugetlb_acct_memory(h, chg); 2888 if (ret < 0) { 2889 hugetlb_put_quota(inode->i_mapping, chg); 2890 return ret; 2891 } 2892 2893 /* 2894 * Account for the reservations made. Shared mappings record regions 2895 * that have reservations as they are shared by multiple VMAs. 2896 * When the last VMA disappears, the region map says how much 2897 * the reservation was and the page cache tells how much of 2898 * the reservation was consumed. Private mappings are per-VMA and 2899 * only the consumed reservations are tracked. When the VMA 2900 * disappears, the original reservation is the VMA size and the 2901 * consumed reservations are stored in the map. Hence, nothing 2902 * else has to be done for private mappings here 2903 */ 2904 if (!vma || vma->vm_flags & VM_MAYSHARE) 2905 region_add(&inode->i_mapping->private_list, from, to); 2906 return 0; 2907} 2908 2909void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 2910{ 2911 struct hstate *h = hstate_inode(inode); 2912 long chg = region_truncate(&inode->i_mapping->private_list, offset); 2913 2914 spin_lock(&inode->i_lock); 2915 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 2916 spin_unlock(&inode->i_lock); 2917 2918 hugetlb_put_quota(inode->i_mapping, (chg - freed)); 2919 hugetlb_acct_memory(h, -(chg - freed)); 2920} 2921 2922#ifdef CONFIG_MEMORY_FAILURE 2923 2924/* Should be called in hugetlb_lock */ 2925static int is_hugepage_on_freelist(struct page *hpage) 2926{ 2927 struct page *page; 2928 struct page *tmp; 2929 struct hstate *h = page_hstate(hpage); 2930 int nid = page_to_nid(hpage); 2931 2932 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) 2933 if (page == hpage) 2934 return 1; 2935 return 0; 2936} 2937 2938/* 2939 * This function is called from memory failure code. 2940 * Assume the caller holds page lock of the head page. 2941 */ 2942int dequeue_hwpoisoned_huge_page(struct page *hpage) 2943{ 2944 struct hstate *h = page_hstate(hpage); 2945 int nid = page_to_nid(hpage); 2946 int ret = -EBUSY; 2947 2948 spin_lock(&hugetlb_lock); 2949 if (is_hugepage_on_freelist(hpage)) { 2950 list_del(&hpage->lru); 2951 set_page_refcounted(hpage); 2952 h->free_huge_pages--; 2953 h->free_huge_pages_node[nid]--; 2954 ret = 0; 2955 } 2956 spin_unlock(&hugetlb_lock); 2957 return ret; 2958} 2959#endif 2960