hugetlb.c revision 8a21346058ad946134b6ddfeb5de975c3cfcf5da
1/* 2 * Generic hugetlb support. 3 * (C) William Irwin, April 2004 4 */ 5#include <linux/gfp.h> 6#include <linux/list.h> 7#include <linux/init.h> 8#include <linux/module.h> 9#include <linux/mm.h> 10#include <linux/sysctl.h> 11#include <linux/highmem.h> 12#include <linux/nodemask.h> 13#include <linux/pagemap.h> 14#include <linux/mempolicy.h> 15#include <linux/cpuset.h> 16#include <linux/mutex.h> 17#include <linux/bootmem.h> 18#include <linux/sysfs.h> 19 20#include <asm/page.h> 21#include <asm/pgtable.h> 22 23#include <linux/hugetlb.h> 24#include "internal.h" 25 26const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 27static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 28unsigned long hugepages_treat_as_movable; 29 30static int max_hstate; 31unsigned int default_hstate_idx; 32struct hstate hstates[HUGE_MAX_HSTATE]; 33 34__initdata LIST_HEAD(huge_boot_pages); 35 36/* for command line parsing */ 37static struct hstate * __initdata parsed_hstate; 38static unsigned long __initdata default_hstate_max_huge_pages; 39static unsigned long __initdata default_hstate_size; 40 41#define for_each_hstate(h) \ 42 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) 43 44/* 45 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages 46 */ 47static DEFINE_SPINLOCK(hugetlb_lock); 48 49/* 50 * Region tracking -- allows tracking of reservations and instantiated pages 51 * across the pages in a mapping. 52 * 53 * The region data structures are protected by a combination of the mmap_sem 54 * and the hugetlb_instantion_mutex. To access or modify a region the caller 55 * must either hold the mmap_sem for write, or the mmap_sem for read and 56 * the hugetlb_instantiation mutex: 57 * 58 * down_write(&mm->mmap_sem); 59 * or 60 * down_read(&mm->mmap_sem); 61 * mutex_lock(&hugetlb_instantiation_mutex); 62 */ 63struct file_region { 64 struct list_head link; 65 long from; 66 long to; 67}; 68 69static long region_add(struct list_head *head, long f, long t) 70{ 71 struct file_region *rg, *nrg, *trg; 72 73 /* Locate the region we are either in or before. */ 74 list_for_each_entry(rg, head, link) 75 if (f <= rg->to) 76 break; 77 78 /* Round our left edge to the current segment if it encloses us. */ 79 if (f > rg->from) 80 f = rg->from; 81 82 /* Check for and consume any regions we now overlap with. */ 83 nrg = rg; 84 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 85 if (&rg->link == head) 86 break; 87 if (rg->from > t) 88 break; 89 90 /* If this area reaches higher then extend our area to 91 * include it completely. If this is not the first area 92 * which we intend to reuse, free it. */ 93 if (rg->to > t) 94 t = rg->to; 95 if (rg != nrg) { 96 list_del(&rg->link); 97 kfree(rg); 98 } 99 } 100 nrg->from = f; 101 nrg->to = t; 102 return 0; 103} 104 105static long region_chg(struct list_head *head, long f, long t) 106{ 107 struct file_region *rg, *nrg; 108 long chg = 0; 109 110 /* Locate the region we are before or in. */ 111 list_for_each_entry(rg, head, link) 112 if (f <= rg->to) 113 break; 114 115 /* If we are below the current region then a new region is required. 116 * Subtle, allocate a new region at the position but make it zero 117 * size such that we can guarantee to record the reservation. */ 118 if (&rg->link == head || t < rg->from) { 119 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 120 if (!nrg) 121 return -ENOMEM; 122 nrg->from = f; 123 nrg->to = f; 124 INIT_LIST_HEAD(&nrg->link); 125 list_add(&nrg->link, rg->link.prev); 126 127 return t - f; 128 } 129 130 /* Round our left edge to the current segment if it encloses us. */ 131 if (f > rg->from) 132 f = rg->from; 133 chg = t - f; 134 135 /* Check for and consume any regions we now overlap with. */ 136 list_for_each_entry(rg, rg->link.prev, link) { 137 if (&rg->link == head) 138 break; 139 if (rg->from > t) 140 return chg; 141 142 /* We overlap with this area, if it extends futher than 143 * us then we must extend ourselves. Account for its 144 * existing reservation. */ 145 if (rg->to > t) { 146 chg += rg->to - t; 147 t = rg->to; 148 } 149 chg -= rg->to - rg->from; 150 } 151 return chg; 152} 153 154static long region_truncate(struct list_head *head, long end) 155{ 156 struct file_region *rg, *trg; 157 long chg = 0; 158 159 /* Locate the region we are either in or before. */ 160 list_for_each_entry(rg, head, link) 161 if (end <= rg->to) 162 break; 163 if (&rg->link == head) 164 return 0; 165 166 /* If we are in the middle of a region then adjust it. */ 167 if (end > rg->from) { 168 chg = rg->to - end; 169 rg->to = end; 170 rg = list_entry(rg->link.next, typeof(*rg), link); 171 } 172 173 /* Drop any remaining regions. */ 174 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 175 if (&rg->link == head) 176 break; 177 chg += rg->to - rg->from; 178 list_del(&rg->link); 179 kfree(rg); 180 } 181 return chg; 182} 183 184static long region_count(struct list_head *head, long f, long t) 185{ 186 struct file_region *rg; 187 long chg = 0; 188 189 /* Locate each segment we overlap with, and count that overlap. */ 190 list_for_each_entry(rg, head, link) { 191 int seg_from; 192 int seg_to; 193 194 if (rg->to <= f) 195 continue; 196 if (rg->from >= t) 197 break; 198 199 seg_from = max(rg->from, f); 200 seg_to = min(rg->to, t); 201 202 chg += seg_to - seg_from; 203 } 204 205 return chg; 206} 207 208/* 209 * Convert the address within this vma to the page offset within 210 * the mapping, in pagecache page units; huge pages here. 211 */ 212static pgoff_t vma_hugecache_offset(struct hstate *h, 213 struct vm_area_struct *vma, unsigned long address) 214{ 215 return ((address - vma->vm_start) >> huge_page_shift(h)) + 216 (vma->vm_pgoff >> huge_page_order(h)); 217} 218 219/* 220 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 221 * bits of the reservation map pointer, which are always clear due to 222 * alignment. 223 */ 224#define HPAGE_RESV_OWNER (1UL << 0) 225#define HPAGE_RESV_UNMAPPED (1UL << 1) 226#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 227 228/* 229 * These helpers are used to track how many pages are reserved for 230 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 231 * is guaranteed to have their future faults succeed. 232 * 233 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 234 * the reserve counters are updated with the hugetlb_lock held. It is safe 235 * to reset the VMA at fork() time as it is not in use yet and there is no 236 * chance of the global counters getting corrupted as a result of the values. 237 * 238 * The private mapping reservation is represented in a subtly different 239 * manner to a shared mapping. A shared mapping has a region map associated 240 * with the underlying file, this region map represents the backing file 241 * pages which have ever had a reservation assigned which this persists even 242 * after the page is instantiated. A private mapping has a region map 243 * associated with the original mmap which is attached to all VMAs which 244 * reference it, this region map represents those offsets which have consumed 245 * reservation ie. where pages have been instantiated. 246 */ 247static unsigned long get_vma_private_data(struct vm_area_struct *vma) 248{ 249 return (unsigned long)vma->vm_private_data; 250} 251 252static void set_vma_private_data(struct vm_area_struct *vma, 253 unsigned long value) 254{ 255 vma->vm_private_data = (void *)value; 256} 257 258struct resv_map { 259 struct kref refs; 260 struct list_head regions; 261}; 262 263struct resv_map *resv_map_alloc(void) 264{ 265 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 266 if (!resv_map) 267 return NULL; 268 269 kref_init(&resv_map->refs); 270 INIT_LIST_HEAD(&resv_map->regions); 271 272 return resv_map; 273} 274 275void resv_map_release(struct kref *ref) 276{ 277 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 278 279 /* Clear out any active regions before we release the map. */ 280 region_truncate(&resv_map->regions, 0); 281 kfree(resv_map); 282} 283 284static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 285{ 286 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 287 if (!(vma->vm_flags & VM_SHARED)) 288 return (struct resv_map *)(get_vma_private_data(vma) & 289 ~HPAGE_RESV_MASK); 290 return 0; 291} 292 293static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 294{ 295 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 296 VM_BUG_ON(vma->vm_flags & VM_SHARED); 297 298 set_vma_private_data(vma, (get_vma_private_data(vma) & 299 HPAGE_RESV_MASK) | (unsigned long)map); 300} 301 302static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 303{ 304 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 305 VM_BUG_ON(vma->vm_flags & VM_SHARED); 306 307 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 308} 309 310static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 311{ 312 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 313 314 return (get_vma_private_data(vma) & flag) != 0; 315} 316 317/* Decrement the reserved pages in the hugepage pool by one */ 318static void decrement_hugepage_resv_vma(struct hstate *h, 319 struct vm_area_struct *vma) 320{ 321 if (vma->vm_flags & VM_NORESERVE) 322 return; 323 324 if (vma->vm_flags & VM_SHARED) { 325 /* Shared mappings always use reserves */ 326 h->resv_huge_pages--; 327 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 328 /* 329 * Only the process that called mmap() has reserves for 330 * private mappings. 331 */ 332 h->resv_huge_pages--; 333 } 334} 335 336/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 337void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 338{ 339 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 340 if (!(vma->vm_flags & VM_SHARED)) 341 vma->vm_private_data = (void *)0; 342} 343 344/* Returns true if the VMA has associated reserve pages */ 345static int vma_has_reserves(struct vm_area_struct *vma) 346{ 347 if (vma->vm_flags & VM_SHARED) 348 return 1; 349 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 350 return 1; 351 return 0; 352} 353 354static void clear_huge_page(struct page *page, 355 unsigned long addr, unsigned long sz) 356{ 357 int i; 358 359 might_sleep(); 360 for (i = 0; i < sz/PAGE_SIZE; i++) { 361 cond_resched(); 362 clear_user_highpage(page + i, addr + i * PAGE_SIZE); 363 } 364} 365 366static void copy_huge_page(struct page *dst, struct page *src, 367 unsigned long addr, struct vm_area_struct *vma) 368{ 369 int i; 370 struct hstate *h = hstate_vma(vma); 371 372 might_sleep(); 373 for (i = 0; i < pages_per_huge_page(h); i++) { 374 cond_resched(); 375 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); 376 } 377} 378 379static void enqueue_huge_page(struct hstate *h, struct page *page) 380{ 381 int nid = page_to_nid(page); 382 list_add(&page->lru, &h->hugepage_freelists[nid]); 383 h->free_huge_pages++; 384 h->free_huge_pages_node[nid]++; 385} 386 387static struct page *dequeue_huge_page(struct hstate *h) 388{ 389 int nid; 390 struct page *page = NULL; 391 392 for (nid = 0; nid < MAX_NUMNODES; ++nid) { 393 if (!list_empty(&h->hugepage_freelists[nid])) { 394 page = list_entry(h->hugepage_freelists[nid].next, 395 struct page, lru); 396 list_del(&page->lru); 397 h->free_huge_pages--; 398 h->free_huge_pages_node[nid]--; 399 break; 400 } 401 } 402 return page; 403} 404 405static struct page *dequeue_huge_page_vma(struct hstate *h, 406 struct vm_area_struct *vma, 407 unsigned long address, int avoid_reserve) 408{ 409 int nid; 410 struct page *page = NULL; 411 struct mempolicy *mpol; 412 nodemask_t *nodemask; 413 struct zonelist *zonelist = huge_zonelist(vma, address, 414 htlb_alloc_mask, &mpol, &nodemask); 415 struct zone *zone; 416 struct zoneref *z; 417 418 /* 419 * A child process with MAP_PRIVATE mappings created by their parent 420 * have no page reserves. This check ensures that reservations are 421 * not "stolen". The child may still get SIGKILLed 422 */ 423 if (!vma_has_reserves(vma) && 424 h->free_huge_pages - h->resv_huge_pages == 0) 425 return NULL; 426 427 /* If reserves cannot be used, ensure enough pages are in the pool */ 428 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 429 return NULL; 430 431 for_each_zone_zonelist_nodemask(zone, z, zonelist, 432 MAX_NR_ZONES - 1, nodemask) { 433 nid = zone_to_nid(zone); 434 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && 435 !list_empty(&h->hugepage_freelists[nid])) { 436 page = list_entry(h->hugepage_freelists[nid].next, 437 struct page, lru); 438 list_del(&page->lru); 439 h->free_huge_pages--; 440 h->free_huge_pages_node[nid]--; 441 442 if (!avoid_reserve) 443 decrement_hugepage_resv_vma(h, vma); 444 445 break; 446 } 447 } 448 mpol_cond_put(mpol); 449 return page; 450} 451 452static void update_and_free_page(struct hstate *h, struct page *page) 453{ 454 int i; 455 456 h->nr_huge_pages--; 457 h->nr_huge_pages_node[page_to_nid(page)]--; 458 for (i = 0; i < pages_per_huge_page(h); i++) { 459 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 460 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 461 1 << PG_private | 1<< PG_writeback); 462 } 463 set_compound_page_dtor(page, NULL); 464 set_page_refcounted(page); 465 arch_release_hugepage(page); 466 __free_pages(page, huge_page_order(h)); 467} 468 469struct hstate *size_to_hstate(unsigned long size) 470{ 471 struct hstate *h; 472 473 for_each_hstate(h) { 474 if (huge_page_size(h) == size) 475 return h; 476 } 477 return NULL; 478} 479 480static void free_huge_page(struct page *page) 481{ 482 /* 483 * Can't pass hstate in here because it is called from the 484 * compound page destructor. 485 */ 486 struct hstate *h = page_hstate(page); 487 int nid = page_to_nid(page); 488 struct address_space *mapping; 489 490 mapping = (struct address_space *) page_private(page); 491 set_page_private(page, 0); 492 BUG_ON(page_count(page)); 493 INIT_LIST_HEAD(&page->lru); 494 495 spin_lock(&hugetlb_lock); 496 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 497 update_and_free_page(h, page); 498 h->surplus_huge_pages--; 499 h->surplus_huge_pages_node[nid]--; 500 } else { 501 enqueue_huge_page(h, page); 502 } 503 spin_unlock(&hugetlb_lock); 504 if (mapping) 505 hugetlb_put_quota(mapping, 1); 506} 507 508/* 509 * Increment or decrement surplus_huge_pages. Keep node-specific counters 510 * balanced by operating on them in a round-robin fashion. 511 * Returns 1 if an adjustment was made. 512 */ 513static int adjust_pool_surplus(struct hstate *h, int delta) 514{ 515 static int prev_nid; 516 int nid = prev_nid; 517 int ret = 0; 518 519 VM_BUG_ON(delta != -1 && delta != 1); 520 do { 521 nid = next_node(nid, node_online_map); 522 if (nid == MAX_NUMNODES) 523 nid = first_node(node_online_map); 524 525 /* To shrink on this node, there must be a surplus page */ 526 if (delta < 0 && !h->surplus_huge_pages_node[nid]) 527 continue; 528 /* Surplus cannot exceed the total number of pages */ 529 if (delta > 0 && h->surplus_huge_pages_node[nid] >= 530 h->nr_huge_pages_node[nid]) 531 continue; 532 533 h->surplus_huge_pages += delta; 534 h->surplus_huge_pages_node[nid] += delta; 535 ret = 1; 536 break; 537 } while (nid != prev_nid); 538 539 prev_nid = nid; 540 return ret; 541} 542 543static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 544{ 545 set_compound_page_dtor(page, free_huge_page); 546 spin_lock(&hugetlb_lock); 547 h->nr_huge_pages++; 548 h->nr_huge_pages_node[nid]++; 549 spin_unlock(&hugetlb_lock); 550 put_page(page); /* free it into the hugepage allocator */ 551} 552 553static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 554{ 555 struct page *page; 556 557 if (h->order >= MAX_ORDER) 558 return NULL; 559 560 page = alloc_pages_node(nid, 561 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 562 __GFP_REPEAT|__GFP_NOWARN, 563 huge_page_order(h)); 564 if (page) { 565 if (arch_prepare_hugepage(page)) { 566 __free_pages(page, HUGETLB_PAGE_ORDER); 567 return NULL; 568 } 569 prep_new_huge_page(h, page, nid); 570 } 571 572 return page; 573} 574 575/* 576 * Use a helper variable to find the next node and then 577 * copy it back to hugetlb_next_nid afterwards: 578 * otherwise there's a window in which a racer might 579 * pass invalid nid MAX_NUMNODES to alloc_pages_node. 580 * But we don't need to use a spin_lock here: it really 581 * doesn't matter if occasionally a racer chooses the 582 * same nid as we do. Move nid forward in the mask even 583 * if we just successfully allocated a hugepage so that 584 * the next caller gets hugepages on the next node. 585 */ 586static int hstate_next_node(struct hstate *h) 587{ 588 int next_nid; 589 next_nid = next_node(h->hugetlb_next_nid, node_online_map); 590 if (next_nid == MAX_NUMNODES) 591 next_nid = first_node(node_online_map); 592 h->hugetlb_next_nid = next_nid; 593 return next_nid; 594} 595 596static int alloc_fresh_huge_page(struct hstate *h) 597{ 598 struct page *page; 599 int start_nid; 600 int next_nid; 601 int ret = 0; 602 603 start_nid = h->hugetlb_next_nid; 604 605 do { 606 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid); 607 if (page) 608 ret = 1; 609 next_nid = hstate_next_node(h); 610 } while (!page && h->hugetlb_next_nid != start_nid); 611 612 if (ret) 613 count_vm_event(HTLB_BUDDY_PGALLOC); 614 else 615 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 616 617 return ret; 618} 619 620static struct page *alloc_buddy_huge_page(struct hstate *h, 621 struct vm_area_struct *vma, unsigned long address) 622{ 623 struct page *page; 624 unsigned int nid; 625 626 if (h->order >= MAX_ORDER) 627 return NULL; 628 629 /* 630 * Assume we will successfully allocate the surplus page to 631 * prevent racing processes from causing the surplus to exceed 632 * overcommit 633 * 634 * This however introduces a different race, where a process B 635 * tries to grow the static hugepage pool while alloc_pages() is 636 * called by process A. B will only examine the per-node 637 * counters in determining if surplus huge pages can be 638 * converted to normal huge pages in adjust_pool_surplus(). A 639 * won't be able to increment the per-node counter, until the 640 * lock is dropped by B, but B doesn't drop hugetlb_lock until 641 * no more huge pages can be converted from surplus to normal 642 * state (and doesn't try to convert again). Thus, we have a 643 * case where a surplus huge page exists, the pool is grown, and 644 * the surplus huge page still exists after, even though it 645 * should just have been converted to a normal huge page. This 646 * does not leak memory, though, as the hugepage will be freed 647 * once it is out of use. It also does not allow the counters to 648 * go out of whack in adjust_pool_surplus() as we don't modify 649 * the node values until we've gotten the hugepage and only the 650 * per-node value is checked there. 651 */ 652 spin_lock(&hugetlb_lock); 653 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 654 spin_unlock(&hugetlb_lock); 655 return NULL; 656 } else { 657 h->nr_huge_pages++; 658 h->surplus_huge_pages++; 659 } 660 spin_unlock(&hugetlb_lock); 661 662 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 663 __GFP_REPEAT|__GFP_NOWARN, 664 huge_page_order(h)); 665 666 spin_lock(&hugetlb_lock); 667 if (page) { 668 /* 669 * This page is now managed by the hugetlb allocator and has 670 * no users -- drop the buddy allocator's reference. 671 */ 672 put_page_testzero(page); 673 VM_BUG_ON(page_count(page)); 674 nid = page_to_nid(page); 675 set_compound_page_dtor(page, free_huge_page); 676 /* 677 * We incremented the global counters already 678 */ 679 h->nr_huge_pages_node[nid]++; 680 h->surplus_huge_pages_node[nid]++; 681 __count_vm_event(HTLB_BUDDY_PGALLOC); 682 } else { 683 h->nr_huge_pages--; 684 h->surplus_huge_pages--; 685 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 686 } 687 spin_unlock(&hugetlb_lock); 688 689 return page; 690} 691 692/* 693 * Increase the hugetlb pool such that it can accomodate a reservation 694 * of size 'delta'. 695 */ 696static int gather_surplus_pages(struct hstate *h, int delta) 697{ 698 struct list_head surplus_list; 699 struct page *page, *tmp; 700 int ret, i; 701 int needed, allocated; 702 703 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 704 if (needed <= 0) { 705 h->resv_huge_pages += delta; 706 return 0; 707 } 708 709 allocated = 0; 710 INIT_LIST_HEAD(&surplus_list); 711 712 ret = -ENOMEM; 713retry: 714 spin_unlock(&hugetlb_lock); 715 for (i = 0; i < needed; i++) { 716 page = alloc_buddy_huge_page(h, NULL, 0); 717 if (!page) { 718 /* 719 * We were not able to allocate enough pages to 720 * satisfy the entire reservation so we free what 721 * we've allocated so far. 722 */ 723 spin_lock(&hugetlb_lock); 724 needed = 0; 725 goto free; 726 } 727 728 list_add(&page->lru, &surplus_list); 729 } 730 allocated += needed; 731 732 /* 733 * After retaking hugetlb_lock, we need to recalculate 'needed' 734 * because either resv_huge_pages or free_huge_pages may have changed. 735 */ 736 spin_lock(&hugetlb_lock); 737 needed = (h->resv_huge_pages + delta) - 738 (h->free_huge_pages + allocated); 739 if (needed > 0) 740 goto retry; 741 742 /* 743 * The surplus_list now contains _at_least_ the number of extra pages 744 * needed to accomodate the reservation. Add the appropriate number 745 * of pages to the hugetlb pool and free the extras back to the buddy 746 * allocator. Commit the entire reservation here to prevent another 747 * process from stealing the pages as they are added to the pool but 748 * before they are reserved. 749 */ 750 needed += allocated; 751 h->resv_huge_pages += delta; 752 ret = 0; 753free: 754 /* Free the needed pages to the hugetlb pool */ 755 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 756 if ((--needed) < 0) 757 break; 758 list_del(&page->lru); 759 enqueue_huge_page(h, page); 760 } 761 762 /* Free unnecessary surplus pages to the buddy allocator */ 763 if (!list_empty(&surplus_list)) { 764 spin_unlock(&hugetlb_lock); 765 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 766 list_del(&page->lru); 767 /* 768 * The page has a reference count of zero already, so 769 * call free_huge_page directly instead of using 770 * put_page. This must be done with hugetlb_lock 771 * unlocked which is safe because free_huge_page takes 772 * hugetlb_lock before deciding how to free the page. 773 */ 774 free_huge_page(page); 775 } 776 spin_lock(&hugetlb_lock); 777 } 778 779 return ret; 780} 781 782/* 783 * When releasing a hugetlb pool reservation, any surplus pages that were 784 * allocated to satisfy the reservation must be explicitly freed if they were 785 * never used. 786 */ 787static void return_unused_surplus_pages(struct hstate *h, 788 unsigned long unused_resv_pages) 789{ 790 static int nid = -1; 791 struct page *page; 792 unsigned long nr_pages; 793 794 /* 795 * We want to release as many surplus pages as possible, spread 796 * evenly across all nodes. Iterate across all nodes until we 797 * can no longer free unreserved surplus pages. This occurs when 798 * the nodes with surplus pages have no free pages. 799 */ 800 unsigned long remaining_iterations = num_online_nodes(); 801 802 /* Uncommit the reservation */ 803 h->resv_huge_pages -= unused_resv_pages; 804 805 /* Cannot return gigantic pages currently */ 806 if (h->order >= MAX_ORDER) 807 return; 808 809 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 810 811 while (remaining_iterations-- && nr_pages) { 812 nid = next_node(nid, node_online_map); 813 if (nid == MAX_NUMNODES) 814 nid = first_node(node_online_map); 815 816 if (!h->surplus_huge_pages_node[nid]) 817 continue; 818 819 if (!list_empty(&h->hugepage_freelists[nid])) { 820 page = list_entry(h->hugepage_freelists[nid].next, 821 struct page, lru); 822 list_del(&page->lru); 823 update_and_free_page(h, page); 824 h->free_huge_pages--; 825 h->free_huge_pages_node[nid]--; 826 h->surplus_huge_pages--; 827 h->surplus_huge_pages_node[nid]--; 828 nr_pages--; 829 remaining_iterations = num_online_nodes(); 830 } 831 } 832} 833 834/* 835 * Determine if the huge page at addr within the vma has an associated 836 * reservation. Where it does not we will need to logically increase 837 * reservation and actually increase quota before an allocation can occur. 838 * Where any new reservation would be required the reservation change is 839 * prepared, but not committed. Once the page has been quota'd allocated 840 * an instantiated the change should be committed via vma_commit_reservation. 841 * No action is required on failure. 842 */ 843static int vma_needs_reservation(struct hstate *h, 844 struct vm_area_struct *vma, unsigned long addr) 845{ 846 struct address_space *mapping = vma->vm_file->f_mapping; 847 struct inode *inode = mapping->host; 848 849 if (vma->vm_flags & VM_SHARED) { 850 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 851 return region_chg(&inode->i_mapping->private_list, 852 idx, idx + 1); 853 854 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 855 return 1; 856 857 } else { 858 int err; 859 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 860 struct resv_map *reservations = vma_resv_map(vma); 861 862 err = region_chg(&reservations->regions, idx, idx + 1); 863 if (err < 0) 864 return err; 865 return 0; 866 } 867} 868static void vma_commit_reservation(struct hstate *h, 869 struct vm_area_struct *vma, unsigned long addr) 870{ 871 struct address_space *mapping = vma->vm_file->f_mapping; 872 struct inode *inode = mapping->host; 873 874 if (vma->vm_flags & VM_SHARED) { 875 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 876 region_add(&inode->i_mapping->private_list, idx, idx + 1); 877 878 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 879 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 880 struct resv_map *reservations = vma_resv_map(vma); 881 882 /* Mark this page used in the map. */ 883 region_add(&reservations->regions, idx, idx + 1); 884 } 885} 886 887static struct page *alloc_huge_page(struct vm_area_struct *vma, 888 unsigned long addr, int avoid_reserve) 889{ 890 struct hstate *h = hstate_vma(vma); 891 struct page *page; 892 struct address_space *mapping = vma->vm_file->f_mapping; 893 struct inode *inode = mapping->host; 894 unsigned int chg; 895 896 /* 897 * Processes that did not create the mapping will have no reserves and 898 * will not have accounted against quota. Check that the quota can be 899 * made before satisfying the allocation 900 * MAP_NORESERVE mappings may also need pages and quota allocated 901 * if no reserve mapping overlaps. 902 */ 903 chg = vma_needs_reservation(h, vma, addr); 904 if (chg < 0) 905 return ERR_PTR(chg); 906 if (chg) 907 if (hugetlb_get_quota(inode->i_mapping, chg)) 908 return ERR_PTR(-ENOSPC); 909 910 spin_lock(&hugetlb_lock); 911 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 912 spin_unlock(&hugetlb_lock); 913 914 if (!page) { 915 page = alloc_buddy_huge_page(h, vma, addr); 916 if (!page) { 917 hugetlb_put_quota(inode->i_mapping, chg); 918 return ERR_PTR(-VM_FAULT_OOM); 919 } 920 } 921 922 set_page_refcounted(page); 923 set_page_private(page, (unsigned long) mapping); 924 925 vma_commit_reservation(h, vma, addr); 926 927 return page; 928} 929 930__attribute__((weak)) int alloc_bootmem_huge_page(struct hstate *h) 931{ 932 struct huge_bootmem_page *m; 933 int nr_nodes = nodes_weight(node_online_map); 934 935 while (nr_nodes) { 936 void *addr; 937 938 addr = __alloc_bootmem_node_nopanic( 939 NODE_DATA(h->hugetlb_next_nid), 940 huge_page_size(h), huge_page_size(h), 0); 941 942 if (addr) { 943 /* 944 * Use the beginning of the huge page to store the 945 * huge_bootmem_page struct (until gather_bootmem 946 * puts them into the mem_map). 947 */ 948 m = addr; 949 if (m) 950 goto found; 951 } 952 hstate_next_node(h); 953 nr_nodes--; 954 } 955 return 0; 956 957found: 958 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 959 /* Put them into a private list first because mem_map is not up yet */ 960 list_add(&m->list, &huge_boot_pages); 961 m->hstate = h; 962 return 1; 963} 964 965/* Put bootmem huge pages into the standard lists after mem_map is up */ 966static void __init gather_bootmem_prealloc(void) 967{ 968 struct huge_bootmem_page *m; 969 970 list_for_each_entry(m, &huge_boot_pages, list) { 971 struct page *page = virt_to_page(m); 972 struct hstate *h = m->hstate; 973 __ClearPageReserved(page); 974 WARN_ON(page_count(page) != 1); 975 prep_compound_page(page, h->order); 976 prep_new_huge_page(h, page, page_to_nid(page)); 977 } 978} 979 980static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 981{ 982 unsigned long i; 983 984 for (i = 0; i < h->max_huge_pages; ++i) { 985 if (h->order >= MAX_ORDER) { 986 if (!alloc_bootmem_huge_page(h)) 987 break; 988 } else if (!alloc_fresh_huge_page(h)) 989 break; 990 } 991 h->max_huge_pages = i; 992} 993 994static void __init hugetlb_init_hstates(void) 995{ 996 struct hstate *h; 997 998 for_each_hstate(h) { 999 /* oversize hugepages were init'ed in early boot */ 1000 if (h->order < MAX_ORDER) 1001 hugetlb_hstate_alloc_pages(h); 1002 } 1003} 1004 1005static char * __init memfmt(char *buf, unsigned long n) 1006{ 1007 if (n >= (1UL << 30)) 1008 sprintf(buf, "%lu GB", n >> 30); 1009 else if (n >= (1UL << 20)) 1010 sprintf(buf, "%lu MB", n >> 20); 1011 else 1012 sprintf(buf, "%lu KB", n >> 10); 1013 return buf; 1014} 1015 1016static void __init report_hugepages(void) 1017{ 1018 struct hstate *h; 1019 1020 for_each_hstate(h) { 1021 char buf[32]; 1022 printk(KERN_INFO "HugeTLB registered %s page size, " 1023 "pre-allocated %ld pages\n", 1024 memfmt(buf, huge_page_size(h)), 1025 h->free_huge_pages); 1026 } 1027} 1028 1029#ifdef CONFIG_HIGHMEM 1030static void try_to_free_low(struct hstate *h, unsigned long count) 1031{ 1032 int i; 1033 1034 if (h->order >= MAX_ORDER) 1035 return; 1036 1037 for (i = 0; i < MAX_NUMNODES; ++i) { 1038 struct page *page, *next; 1039 struct list_head *freel = &h->hugepage_freelists[i]; 1040 list_for_each_entry_safe(page, next, freel, lru) { 1041 if (count >= h->nr_huge_pages) 1042 return; 1043 if (PageHighMem(page)) 1044 continue; 1045 list_del(&page->lru); 1046 update_and_free_page(h, page); 1047 h->free_huge_pages--; 1048 h->free_huge_pages_node[page_to_nid(page)]--; 1049 } 1050 } 1051} 1052#else 1053static inline void try_to_free_low(struct hstate *h, unsigned long count) 1054{ 1055} 1056#endif 1057 1058#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1059static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count) 1060{ 1061 unsigned long min_count, ret; 1062 1063 if (h->order >= MAX_ORDER) 1064 return h->max_huge_pages; 1065 1066 /* 1067 * Increase the pool size 1068 * First take pages out of surplus state. Then make up the 1069 * remaining difference by allocating fresh huge pages. 1070 * 1071 * We might race with alloc_buddy_huge_page() here and be unable 1072 * to convert a surplus huge page to a normal huge page. That is 1073 * not critical, though, it just means the overall size of the 1074 * pool might be one hugepage larger than it needs to be, but 1075 * within all the constraints specified by the sysctls. 1076 */ 1077 spin_lock(&hugetlb_lock); 1078 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1079 if (!adjust_pool_surplus(h, -1)) 1080 break; 1081 } 1082 1083 while (count > persistent_huge_pages(h)) { 1084 /* 1085 * If this allocation races such that we no longer need the 1086 * page, free_huge_page will handle it by freeing the page 1087 * and reducing the surplus. 1088 */ 1089 spin_unlock(&hugetlb_lock); 1090 ret = alloc_fresh_huge_page(h); 1091 spin_lock(&hugetlb_lock); 1092 if (!ret) 1093 goto out; 1094 1095 } 1096 1097 /* 1098 * Decrease the pool size 1099 * First return free pages to the buddy allocator (being careful 1100 * to keep enough around to satisfy reservations). Then place 1101 * pages into surplus state as needed so the pool will shrink 1102 * to the desired size as pages become free. 1103 * 1104 * By placing pages into the surplus state independent of the 1105 * overcommit value, we are allowing the surplus pool size to 1106 * exceed overcommit. There are few sane options here. Since 1107 * alloc_buddy_huge_page() is checking the global counter, 1108 * though, we'll note that we're not allowed to exceed surplus 1109 * and won't grow the pool anywhere else. Not until one of the 1110 * sysctls are changed, or the surplus pages go out of use. 1111 */ 1112 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1113 min_count = max(count, min_count); 1114 try_to_free_low(h, min_count); 1115 while (min_count < persistent_huge_pages(h)) { 1116 struct page *page = dequeue_huge_page(h); 1117 if (!page) 1118 break; 1119 update_and_free_page(h, page); 1120 } 1121 while (count < persistent_huge_pages(h)) { 1122 if (!adjust_pool_surplus(h, 1)) 1123 break; 1124 } 1125out: 1126 ret = persistent_huge_pages(h); 1127 spin_unlock(&hugetlb_lock); 1128 return ret; 1129} 1130 1131#define HSTATE_ATTR_RO(_name) \ 1132 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1133 1134#define HSTATE_ATTR(_name) \ 1135 static struct kobj_attribute _name##_attr = \ 1136 __ATTR(_name, 0644, _name##_show, _name##_store) 1137 1138static struct kobject *hugepages_kobj; 1139static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1140 1141static struct hstate *kobj_to_hstate(struct kobject *kobj) 1142{ 1143 int i; 1144 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1145 if (hstate_kobjs[i] == kobj) 1146 return &hstates[i]; 1147 BUG(); 1148 return NULL; 1149} 1150 1151static ssize_t nr_hugepages_show(struct kobject *kobj, 1152 struct kobj_attribute *attr, char *buf) 1153{ 1154 struct hstate *h = kobj_to_hstate(kobj); 1155 return sprintf(buf, "%lu\n", h->nr_huge_pages); 1156} 1157static ssize_t nr_hugepages_store(struct kobject *kobj, 1158 struct kobj_attribute *attr, const char *buf, size_t count) 1159{ 1160 int err; 1161 unsigned long input; 1162 struct hstate *h = kobj_to_hstate(kobj); 1163 1164 err = strict_strtoul(buf, 10, &input); 1165 if (err) 1166 return 0; 1167 1168 h->max_huge_pages = set_max_huge_pages(h, input); 1169 1170 return count; 1171} 1172HSTATE_ATTR(nr_hugepages); 1173 1174static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1175 struct kobj_attribute *attr, char *buf) 1176{ 1177 struct hstate *h = kobj_to_hstate(kobj); 1178 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1179} 1180static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1181 struct kobj_attribute *attr, const char *buf, size_t count) 1182{ 1183 int err; 1184 unsigned long input; 1185 struct hstate *h = kobj_to_hstate(kobj); 1186 1187 err = strict_strtoul(buf, 10, &input); 1188 if (err) 1189 return 0; 1190 1191 spin_lock(&hugetlb_lock); 1192 h->nr_overcommit_huge_pages = input; 1193 spin_unlock(&hugetlb_lock); 1194 1195 return count; 1196} 1197HSTATE_ATTR(nr_overcommit_hugepages); 1198 1199static ssize_t free_hugepages_show(struct kobject *kobj, 1200 struct kobj_attribute *attr, char *buf) 1201{ 1202 struct hstate *h = kobj_to_hstate(kobj); 1203 return sprintf(buf, "%lu\n", h->free_huge_pages); 1204} 1205HSTATE_ATTR_RO(free_hugepages); 1206 1207static ssize_t resv_hugepages_show(struct kobject *kobj, 1208 struct kobj_attribute *attr, char *buf) 1209{ 1210 struct hstate *h = kobj_to_hstate(kobj); 1211 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1212} 1213HSTATE_ATTR_RO(resv_hugepages); 1214 1215static ssize_t surplus_hugepages_show(struct kobject *kobj, 1216 struct kobj_attribute *attr, char *buf) 1217{ 1218 struct hstate *h = kobj_to_hstate(kobj); 1219 return sprintf(buf, "%lu\n", h->surplus_huge_pages); 1220} 1221HSTATE_ATTR_RO(surplus_hugepages); 1222 1223static struct attribute *hstate_attrs[] = { 1224 &nr_hugepages_attr.attr, 1225 &nr_overcommit_hugepages_attr.attr, 1226 &free_hugepages_attr.attr, 1227 &resv_hugepages_attr.attr, 1228 &surplus_hugepages_attr.attr, 1229 NULL, 1230}; 1231 1232static struct attribute_group hstate_attr_group = { 1233 .attrs = hstate_attrs, 1234}; 1235 1236static int __init hugetlb_sysfs_add_hstate(struct hstate *h) 1237{ 1238 int retval; 1239 1240 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name, 1241 hugepages_kobj); 1242 if (!hstate_kobjs[h - hstates]) 1243 return -ENOMEM; 1244 1245 retval = sysfs_create_group(hstate_kobjs[h - hstates], 1246 &hstate_attr_group); 1247 if (retval) 1248 kobject_put(hstate_kobjs[h - hstates]); 1249 1250 return retval; 1251} 1252 1253static void __init hugetlb_sysfs_init(void) 1254{ 1255 struct hstate *h; 1256 int err; 1257 1258 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1259 if (!hugepages_kobj) 1260 return; 1261 1262 for_each_hstate(h) { 1263 err = hugetlb_sysfs_add_hstate(h); 1264 if (err) 1265 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1266 h->name); 1267 } 1268} 1269 1270static void __exit hugetlb_exit(void) 1271{ 1272 struct hstate *h; 1273 1274 for_each_hstate(h) { 1275 kobject_put(hstate_kobjs[h - hstates]); 1276 } 1277 1278 kobject_put(hugepages_kobj); 1279} 1280module_exit(hugetlb_exit); 1281 1282static int __init hugetlb_init(void) 1283{ 1284 BUILD_BUG_ON(HPAGE_SHIFT == 0); 1285 1286 if (!size_to_hstate(default_hstate_size)) { 1287 default_hstate_size = HPAGE_SIZE; 1288 if (!size_to_hstate(default_hstate_size)) 1289 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1290 } 1291 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; 1292 if (default_hstate_max_huge_pages) 1293 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1294 1295 hugetlb_init_hstates(); 1296 1297 gather_bootmem_prealloc(); 1298 1299 report_hugepages(); 1300 1301 hugetlb_sysfs_init(); 1302 1303 return 0; 1304} 1305module_init(hugetlb_init); 1306 1307/* Should be called on processing a hugepagesz=... option */ 1308void __init hugetlb_add_hstate(unsigned order) 1309{ 1310 struct hstate *h; 1311 unsigned long i; 1312 1313 if (size_to_hstate(PAGE_SIZE << order)) { 1314 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1315 return; 1316 } 1317 BUG_ON(max_hstate >= HUGE_MAX_HSTATE); 1318 BUG_ON(order == 0); 1319 h = &hstates[max_hstate++]; 1320 h->order = order; 1321 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1322 h->nr_huge_pages = 0; 1323 h->free_huge_pages = 0; 1324 for (i = 0; i < MAX_NUMNODES; ++i) 1325 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1326 h->hugetlb_next_nid = first_node(node_online_map); 1327 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1328 huge_page_size(h)/1024); 1329 1330 parsed_hstate = h; 1331} 1332 1333static int __init hugetlb_nrpages_setup(char *s) 1334{ 1335 unsigned long *mhp; 1336 static unsigned long *last_mhp; 1337 1338 /* 1339 * !max_hstate means we haven't parsed a hugepagesz= parameter yet, 1340 * so this hugepages= parameter goes to the "default hstate". 1341 */ 1342 if (!max_hstate) 1343 mhp = &default_hstate_max_huge_pages; 1344 else 1345 mhp = &parsed_hstate->max_huge_pages; 1346 1347 if (mhp == last_mhp) { 1348 printk(KERN_WARNING "hugepages= specified twice without " 1349 "interleaving hugepagesz=, ignoring\n"); 1350 return 1; 1351 } 1352 1353 if (sscanf(s, "%lu", mhp) <= 0) 1354 *mhp = 0; 1355 1356 /* 1357 * Global state is always initialized later in hugetlb_init. 1358 * But we need to allocate >= MAX_ORDER hstates here early to still 1359 * use the bootmem allocator. 1360 */ 1361 if (max_hstate && parsed_hstate->order >= MAX_ORDER) 1362 hugetlb_hstate_alloc_pages(parsed_hstate); 1363 1364 last_mhp = mhp; 1365 1366 return 1; 1367} 1368__setup("hugepages=", hugetlb_nrpages_setup); 1369 1370static int __init hugetlb_default_setup(char *s) 1371{ 1372 default_hstate_size = memparse(s, &s); 1373 return 1; 1374} 1375__setup("default_hugepagesz=", hugetlb_default_setup); 1376 1377static unsigned int cpuset_mems_nr(unsigned int *array) 1378{ 1379 int node; 1380 unsigned int nr = 0; 1381 1382 for_each_node_mask(node, cpuset_current_mems_allowed) 1383 nr += array[node]; 1384 1385 return nr; 1386} 1387 1388#ifdef CONFIG_SYSCTL 1389int hugetlb_sysctl_handler(struct ctl_table *table, int write, 1390 struct file *file, void __user *buffer, 1391 size_t *length, loff_t *ppos) 1392{ 1393 struct hstate *h = &default_hstate; 1394 unsigned long tmp; 1395 1396 if (!write) 1397 tmp = h->max_huge_pages; 1398 1399 table->data = &tmp; 1400 table->maxlen = sizeof(unsigned long); 1401 proc_doulongvec_minmax(table, write, file, buffer, length, ppos); 1402 1403 if (write) 1404 h->max_huge_pages = set_max_huge_pages(h, tmp); 1405 1406 return 0; 1407} 1408 1409int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 1410 struct file *file, void __user *buffer, 1411 size_t *length, loff_t *ppos) 1412{ 1413 proc_dointvec(table, write, file, buffer, length, ppos); 1414 if (hugepages_treat_as_movable) 1415 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 1416 else 1417 htlb_alloc_mask = GFP_HIGHUSER; 1418 return 0; 1419} 1420 1421int hugetlb_overcommit_handler(struct ctl_table *table, int write, 1422 struct file *file, void __user *buffer, 1423 size_t *length, loff_t *ppos) 1424{ 1425 struct hstate *h = &default_hstate; 1426 unsigned long tmp; 1427 1428 if (!write) 1429 tmp = h->nr_overcommit_huge_pages; 1430 1431 table->data = &tmp; 1432 table->maxlen = sizeof(unsigned long); 1433 proc_doulongvec_minmax(table, write, file, buffer, length, ppos); 1434 1435 if (write) { 1436 spin_lock(&hugetlb_lock); 1437 h->nr_overcommit_huge_pages = tmp; 1438 spin_unlock(&hugetlb_lock); 1439 } 1440 1441 return 0; 1442} 1443 1444#endif /* CONFIG_SYSCTL */ 1445 1446int hugetlb_report_meminfo(char *buf) 1447{ 1448 struct hstate *h = &default_hstate; 1449 return sprintf(buf, 1450 "HugePages_Total: %5lu\n" 1451 "HugePages_Free: %5lu\n" 1452 "HugePages_Rsvd: %5lu\n" 1453 "HugePages_Surp: %5lu\n" 1454 "Hugepagesize: %5lu kB\n", 1455 h->nr_huge_pages, 1456 h->free_huge_pages, 1457 h->resv_huge_pages, 1458 h->surplus_huge_pages, 1459 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 1460} 1461 1462int hugetlb_report_node_meminfo(int nid, char *buf) 1463{ 1464 struct hstate *h = &default_hstate; 1465 return sprintf(buf, 1466 "Node %d HugePages_Total: %5u\n" 1467 "Node %d HugePages_Free: %5u\n" 1468 "Node %d HugePages_Surp: %5u\n", 1469 nid, h->nr_huge_pages_node[nid], 1470 nid, h->free_huge_pages_node[nid], 1471 nid, h->surplus_huge_pages_node[nid]); 1472} 1473 1474/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 1475unsigned long hugetlb_total_pages(void) 1476{ 1477 struct hstate *h = &default_hstate; 1478 return h->nr_huge_pages * pages_per_huge_page(h); 1479} 1480 1481static int hugetlb_acct_memory(struct hstate *h, long delta) 1482{ 1483 int ret = -ENOMEM; 1484 1485 spin_lock(&hugetlb_lock); 1486 /* 1487 * When cpuset is configured, it breaks the strict hugetlb page 1488 * reservation as the accounting is done on a global variable. Such 1489 * reservation is completely rubbish in the presence of cpuset because 1490 * the reservation is not checked against page availability for the 1491 * current cpuset. Application can still potentially OOM'ed by kernel 1492 * with lack of free htlb page in cpuset that the task is in. 1493 * Attempt to enforce strict accounting with cpuset is almost 1494 * impossible (or too ugly) because cpuset is too fluid that 1495 * task or memory node can be dynamically moved between cpusets. 1496 * 1497 * The change of semantics for shared hugetlb mapping with cpuset is 1498 * undesirable. However, in order to preserve some of the semantics, 1499 * we fall back to check against current free page availability as 1500 * a best attempt and hopefully to minimize the impact of changing 1501 * semantics that cpuset has. 1502 */ 1503 if (delta > 0) { 1504 if (gather_surplus_pages(h, delta) < 0) 1505 goto out; 1506 1507 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 1508 return_unused_surplus_pages(h, delta); 1509 goto out; 1510 } 1511 } 1512 1513 ret = 0; 1514 if (delta < 0) 1515 return_unused_surplus_pages(h, (unsigned long) -delta); 1516 1517out: 1518 spin_unlock(&hugetlb_lock); 1519 return ret; 1520} 1521 1522static void hugetlb_vm_op_open(struct vm_area_struct *vma) 1523{ 1524 struct resv_map *reservations = vma_resv_map(vma); 1525 1526 /* 1527 * This new VMA should share its siblings reservation map if present. 1528 * The VMA will only ever have a valid reservation map pointer where 1529 * it is being copied for another still existing VMA. As that VMA 1530 * has a reference to the reservation map it cannot dissappear until 1531 * after this open call completes. It is therefore safe to take a 1532 * new reference here without additional locking. 1533 */ 1534 if (reservations) 1535 kref_get(&reservations->refs); 1536} 1537 1538static void hugetlb_vm_op_close(struct vm_area_struct *vma) 1539{ 1540 struct hstate *h = hstate_vma(vma); 1541 struct resv_map *reservations = vma_resv_map(vma); 1542 unsigned long reserve; 1543 unsigned long start; 1544 unsigned long end; 1545 1546 if (reservations) { 1547 start = vma_hugecache_offset(h, vma, vma->vm_start); 1548 end = vma_hugecache_offset(h, vma, vma->vm_end); 1549 1550 reserve = (end - start) - 1551 region_count(&reservations->regions, start, end); 1552 1553 kref_put(&reservations->refs, resv_map_release); 1554 1555 if (reserve) { 1556 hugetlb_acct_memory(h, -reserve); 1557 hugetlb_put_quota(vma->vm_file->f_mapping, reserve); 1558 } 1559 } 1560} 1561 1562/* 1563 * We cannot handle pagefaults against hugetlb pages at all. They cause 1564 * handle_mm_fault() to try to instantiate regular-sized pages in the 1565 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 1566 * this far. 1567 */ 1568static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 1569{ 1570 BUG(); 1571 return 0; 1572} 1573 1574struct vm_operations_struct hugetlb_vm_ops = { 1575 .fault = hugetlb_vm_op_fault, 1576 .open = hugetlb_vm_op_open, 1577 .close = hugetlb_vm_op_close, 1578}; 1579 1580static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 1581 int writable) 1582{ 1583 pte_t entry; 1584 1585 if (writable) { 1586 entry = 1587 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 1588 } else { 1589 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 1590 } 1591 entry = pte_mkyoung(entry); 1592 entry = pte_mkhuge(entry); 1593 1594 return entry; 1595} 1596 1597static void set_huge_ptep_writable(struct vm_area_struct *vma, 1598 unsigned long address, pte_t *ptep) 1599{ 1600 pte_t entry; 1601 1602 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 1603 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { 1604 update_mmu_cache(vma, address, entry); 1605 } 1606} 1607 1608 1609int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 1610 struct vm_area_struct *vma) 1611{ 1612 pte_t *src_pte, *dst_pte, entry; 1613 struct page *ptepage; 1614 unsigned long addr; 1615 int cow; 1616 struct hstate *h = hstate_vma(vma); 1617 unsigned long sz = huge_page_size(h); 1618 1619 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 1620 1621 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 1622 src_pte = huge_pte_offset(src, addr); 1623 if (!src_pte) 1624 continue; 1625 dst_pte = huge_pte_alloc(dst, addr, sz); 1626 if (!dst_pte) 1627 goto nomem; 1628 1629 /* If the pagetables are shared don't copy or take references */ 1630 if (dst_pte == src_pte) 1631 continue; 1632 1633 spin_lock(&dst->page_table_lock); 1634 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 1635 if (!huge_pte_none(huge_ptep_get(src_pte))) { 1636 if (cow) 1637 huge_ptep_set_wrprotect(src, addr, src_pte); 1638 entry = huge_ptep_get(src_pte); 1639 ptepage = pte_page(entry); 1640 get_page(ptepage); 1641 set_huge_pte_at(dst, addr, dst_pte, entry); 1642 } 1643 spin_unlock(&src->page_table_lock); 1644 spin_unlock(&dst->page_table_lock); 1645 } 1646 return 0; 1647 1648nomem: 1649 return -ENOMEM; 1650} 1651 1652void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 1653 unsigned long end, struct page *ref_page) 1654{ 1655 struct mm_struct *mm = vma->vm_mm; 1656 unsigned long address; 1657 pte_t *ptep; 1658 pte_t pte; 1659 struct page *page; 1660 struct page *tmp; 1661 struct hstate *h = hstate_vma(vma); 1662 unsigned long sz = huge_page_size(h); 1663 1664 /* 1665 * A page gathering list, protected by per file i_mmap_lock. The 1666 * lock is used to avoid list corruption from multiple unmapping 1667 * of the same page since we are using page->lru. 1668 */ 1669 LIST_HEAD(page_list); 1670 1671 WARN_ON(!is_vm_hugetlb_page(vma)); 1672 BUG_ON(start & ~huge_page_mask(h)); 1673 BUG_ON(end & ~huge_page_mask(h)); 1674 1675 spin_lock(&mm->page_table_lock); 1676 for (address = start; address < end; address += sz) { 1677 ptep = huge_pte_offset(mm, address); 1678 if (!ptep) 1679 continue; 1680 1681 if (huge_pmd_unshare(mm, &address, ptep)) 1682 continue; 1683 1684 /* 1685 * If a reference page is supplied, it is because a specific 1686 * page is being unmapped, not a range. Ensure the page we 1687 * are about to unmap is the actual page of interest. 1688 */ 1689 if (ref_page) { 1690 pte = huge_ptep_get(ptep); 1691 if (huge_pte_none(pte)) 1692 continue; 1693 page = pte_page(pte); 1694 if (page != ref_page) 1695 continue; 1696 1697 /* 1698 * Mark the VMA as having unmapped its page so that 1699 * future faults in this VMA will fail rather than 1700 * looking like data was lost 1701 */ 1702 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 1703 } 1704 1705 pte = huge_ptep_get_and_clear(mm, address, ptep); 1706 if (huge_pte_none(pte)) 1707 continue; 1708 1709 page = pte_page(pte); 1710 if (pte_dirty(pte)) 1711 set_page_dirty(page); 1712 list_add(&page->lru, &page_list); 1713 } 1714 spin_unlock(&mm->page_table_lock); 1715 flush_tlb_range(vma, start, end); 1716 list_for_each_entry_safe(page, tmp, &page_list, lru) { 1717 list_del(&page->lru); 1718 put_page(page); 1719 } 1720} 1721 1722void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 1723 unsigned long end, struct page *ref_page) 1724{ 1725 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 1726 __unmap_hugepage_range(vma, start, end, ref_page); 1727 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 1728} 1729 1730/* 1731 * This is called when the original mapper is failing to COW a MAP_PRIVATE 1732 * mappping it owns the reserve page for. The intention is to unmap the page 1733 * from other VMAs and let the children be SIGKILLed if they are faulting the 1734 * same region. 1735 */ 1736int unmap_ref_private(struct mm_struct *mm, 1737 struct vm_area_struct *vma, 1738 struct page *page, 1739 unsigned long address) 1740{ 1741 struct vm_area_struct *iter_vma; 1742 struct address_space *mapping; 1743 struct prio_tree_iter iter; 1744 pgoff_t pgoff; 1745 1746 /* 1747 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 1748 * from page cache lookup which is in HPAGE_SIZE units. 1749 */ 1750 address = address & huge_page_mask(hstate_vma(vma)); 1751 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) 1752 + (vma->vm_pgoff >> PAGE_SHIFT); 1753 mapping = (struct address_space *)page_private(page); 1754 1755 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { 1756 /* Do not unmap the current VMA */ 1757 if (iter_vma == vma) 1758 continue; 1759 1760 /* 1761 * Unmap the page from other VMAs without their own reserves. 1762 * They get marked to be SIGKILLed if they fault in these 1763 * areas. This is because a future no-page fault on this VMA 1764 * could insert a zeroed page instead of the data existing 1765 * from the time of fork. This would look like data corruption 1766 */ 1767 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 1768 unmap_hugepage_range(iter_vma, 1769 address, address + HPAGE_SIZE, 1770 page); 1771 } 1772 1773 return 1; 1774} 1775 1776static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 1777 unsigned long address, pte_t *ptep, pte_t pte, 1778 struct page *pagecache_page) 1779{ 1780 struct hstate *h = hstate_vma(vma); 1781 struct page *old_page, *new_page; 1782 int avoidcopy; 1783 int outside_reserve = 0; 1784 1785 old_page = pte_page(pte); 1786 1787retry_avoidcopy: 1788 /* If no-one else is actually using this page, avoid the copy 1789 * and just make the page writable */ 1790 avoidcopy = (page_count(old_page) == 1); 1791 if (avoidcopy) { 1792 set_huge_ptep_writable(vma, address, ptep); 1793 return 0; 1794 } 1795 1796 /* 1797 * If the process that created a MAP_PRIVATE mapping is about to 1798 * perform a COW due to a shared page count, attempt to satisfy 1799 * the allocation without using the existing reserves. The pagecache 1800 * page is used to determine if the reserve at this address was 1801 * consumed or not. If reserves were used, a partial faulted mapping 1802 * at the time of fork() could consume its reserves on COW instead 1803 * of the full address range. 1804 */ 1805 if (!(vma->vm_flags & VM_SHARED) && 1806 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 1807 old_page != pagecache_page) 1808 outside_reserve = 1; 1809 1810 page_cache_get(old_page); 1811 new_page = alloc_huge_page(vma, address, outside_reserve); 1812 1813 if (IS_ERR(new_page)) { 1814 page_cache_release(old_page); 1815 1816 /* 1817 * If a process owning a MAP_PRIVATE mapping fails to COW, 1818 * it is due to references held by a child and an insufficient 1819 * huge page pool. To guarantee the original mappers 1820 * reliability, unmap the page from child processes. The child 1821 * may get SIGKILLed if it later faults. 1822 */ 1823 if (outside_reserve) { 1824 BUG_ON(huge_pte_none(pte)); 1825 if (unmap_ref_private(mm, vma, old_page, address)) { 1826 BUG_ON(page_count(old_page) != 1); 1827 BUG_ON(huge_pte_none(pte)); 1828 goto retry_avoidcopy; 1829 } 1830 WARN_ON_ONCE(1); 1831 } 1832 1833 return -PTR_ERR(new_page); 1834 } 1835 1836 spin_unlock(&mm->page_table_lock); 1837 copy_huge_page(new_page, old_page, address, vma); 1838 __SetPageUptodate(new_page); 1839 spin_lock(&mm->page_table_lock); 1840 1841 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 1842 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 1843 /* Break COW */ 1844 huge_ptep_clear_flush(vma, address, ptep); 1845 set_huge_pte_at(mm, address, ptep, 1846 make_huge_pte(vma, new_page, 1)); 1847 /* Make the old page be freed below */ 1848 new_page = old_page; 1849 } 1850 page_cache_release(new_page); 1851 page_cache_release(old_page); 1852 return 0; 1853} 1854 1855/* Return the pagecache page at a given address within a VMA */ 1856static struct page *hugetlbfs_pagecache_page(struct hstate *h, 1857 struct vm_area_struct *vma, unsigned long address) 1858{ 1859 struct address_space *mapping; 1860 pgoff_t idx; 1861 1862 mapping = vma->vm_file->f_mapping; 1863 idx = vma_hugecache_offset(h, vma, address); 1864 1865 return find_lock_page(mapping, idx); 1866} 1867 1868static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 1869 unsigned long address, pte_t *ptep, int write_access) 1870{ 1871 struct hstate *h = hstate_vma(vma); 1872 int ret = VM_FAULT_SIGBUS; 1873 pgoff_t idx; 1874 unsigned long size; 1875 struct page *page; 1876 struct address_space *mapping; 1877 pte_t new_pte; 1878 1879 /* 1880 * Currently, we are forced to kill the process in the event the 1881 * original mapper has unmapped pages from the child due to a failed 1882 * COW. Warn that such a situation has occured as it may not be obvious 1883 */ 1884 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 1885 printk(KERN_WARNING 1886 "PID %d killed due to inadequate hugepage pool\n", 1887 current->pid); 1888 return ret; 1889 } 1890 1891 mapping = vma->vm_file->f_mapping; 1892 idx = vma_hugecache_offset(h, vma, address); 1893 1894 /* 1895 * Use page lock to guard against racing truncation 1896 * before we get page_table_lock. 1897 */ 1898retry: 1899 page = find_lock_page(mapping, idx); 1900 if (!page) { 1901 size = i_size_read(mapping->host) >> huge_page_shift(h); 1902 if (idx >= size) 1903 goto out; 1904 page = alloc_huge_page(vma, address, 0); 1905 if (IS_ERR(page)) { 1906 ret = -PTR_ERR(page); 1907 goto out; 1908 } 1909 clear_huge_page(page, address, huge_page_size(h)); 1910 __SetPageUptodate(page); 1911 1912 if (vma->vm_flags & VM_SHARED) { 1913 int err; 1914 struct inode *inode = mapping->host; 1915 1916 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 1917 if (err) { 1918 put_page(page); 1919 if (err == -EEXIST) 1920 goto retry; 1921 goto out; 1922 } 1923 1924 spin_lock(&inode->i_lock); 1925 inode->i_blocks += blocks_per_huge_page(h); 1926 spin_unlock(&inode->i_lock); 1927 } else 1928 lock_page(page); 1929 } 1930 1931 spin_lock(&mm->page_table_lock); 1932 size = i_size_read(mapping->host) >> huge_page_shift(h); 1933 if (idx >= size) 1934 goto backout; 1935 1936 ret = 0; 1937 if (!huge_pte_none(huge_ptep_get(ptep))) 1938 goto backout; 1939 1940 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 1941 && (vma->vm_flags & VM_SHARED))); 1942 set_huge_pte_at(mm, address, ptep, new_pte); 1943 1944 if (write_access && !(vma->vm_flags & VM_SHARED)) { 1945 /* Optimization, do the COW without a second fault */ 1946 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 1947 } 1948 1949 spin_unlock(&mm->page_table_lock); 1950 unlock_page(page); 1951out: 1952 return ret; 1953 1954backout: 1955 spin_unlock(&mm->page_table_lock); 1956 unlock_page(page); 1957 put_page(page); 1958 goto out; 1959} 1960 1961int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 1962 unsigned long address, int write_access) 1963{ 1964 pte_t *ptep; 1965 pte_t entry; 1966 int ret; 1967 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 1968 struct hstate *h = hstate_vma(vma); 1969 1970 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 1971 if (!ptep) 1972 return VM_FAULT_OOM; 1973 1974 /* 1975 * Serialize hugepage allocation and instantiation, so that we don't 1976 * get spurious allocation failures if two CPUs race to instantiate 1977 * the same page in the page cache. 1978 */ 1979 mutex_lock(&hugetlb_instantiation_mutex); 1980 entry = huge_ptep_get(ptep); 1981 if (huge_pte_none(entry)) { 1982 ret = hugetlb_no_page(mm, vma, address, ptep, write_access); 1983 mutex_unlock(&hugetlb_instantiation_mutex); 1984 return ret; 1985 } 1986 1987 ret = 0; 1988 1989 spin_lock(&mm->page_table_lock); 1990 /* Check for a racing update before calling hugetlb_cow */ 1991 if (likely(pte_same(entry, huge_ptep_get(ptep)))) 1992 if (write_access && !pte_write(entry)) { 1993 struct page *page; 1994 page = hugetlbfs_pagecache_page(h, vma, address); 1995 ret = hugetlb_cow(mm, vma, address, ptep, entry, page); 1996 if (page) { 1997 unlock_page(page); 1998 put_page(page); 1999 } 2000 } 2001 spin_unlock(&mm->page_table_lock); 2002 mutex_unlock(&hugetlb_instantiation_mutex); 2003 2004 return ret; 2005} 2006 2007/* Can be overriden by architectures */ 2008__attribute__((weak)) struct page * 2009follow_huge_pud(struct mm_struct *mm, unsigned long address, 2010 pud_t *pud, int write) 2011{ 2012 BUG(); 2013 return NULL; 2014} 2015 2016int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2017 struct page **pages, struct vm_area_struct **vmas, 2018 unsigned long *position, int *length, int i, 2019 int write) 2020{ 2021 unsigned long pfn_offset; 2022 unsigned long vaddr = *position; 2023 int remainder = *length; 2024 struct hstate *h = hstate_vma(vma); 2025 2026 spin_lock(&mm->page_table_lock); 2027 while (vaddr < vma->vm_end && remainder) { 2028 pte_t *pte; 2029 struct page *page; 2030 2031 /* 2032 * Some archs (sparc64, sh*) have multiple pte_ts to 2033 * each hugepage. We have to make * sure we get the 2034 * first, for the page indexing below to work. 2035 */ 2036 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2037 2038 if (!pte || huge_pte_none(huge_ptep_get(pte)) || 2039 (write && !pte_write(huge_ptep_get(pte)))) { 2040 int ret; 2041 2042 spin_unlock(&mm->page_table_lock); 2043 ret = hugetlb_fault(mm, vma, vaddr, write); 2044 spin_lock(&mm->page_table_lock); 2045 if (!(ret & VM_FAULT_ERROR)) 2046 continue; 2047 2048 remainder = 0; 2049 if (!i) 2050 i = -EFAULT; 2051 break; 2052 } 2053 2054 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2055 page = pte_page(huge_ptep_get(pte)); 2056same_page: 2057 if (pages) { 2058 get_page(page); 2059 pages[i] = page + pfn_offset; 2060 } 2061 2062 if (vmas) 2063 vmas[i] = vma; 2064 2065 vaddr += PAGE_SIZE; 2066 ++pfn_offset; 2067 --remainder; 2068 ++i; 2069 if (vaddr < vma->vm_end && remainder && 2070 pfn_offset < pages_per_huge_page(h)) { 2071 /* 2072 * We use pfn_offset to avoid touching the pageframes 2073 * of this compound page. 2074 */ 2075 goto same_page; 2076 } 2077 } 2078 spin_unlock(&mm->page_table_lock); 2079 *length = remainder; 2080 *position = vaddr; 2081 2082 return i; 2083} 2084 2085void hugetlb_change_protection(struct vm_area_struct *vma, 2086 unsigned long address, unsigned long end, pgprot_t newprot) 2087{ 2088 struct mm_struct *mm = vma->vm_mm; 2089 unsigned long start = address; 2090 pte_t *ptep; 2091 pte_t pte; 2092 struct hstate *h = hstate_vma(vma); 2093 2094 BUG_ON(address >= end); 2095 flush_cache_range(vma, address, end); 2096 2097 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2098 spin_lock(&mm->page_table_lock); 2099 for (; address < end; address += huge_page_size(h)) { 2100 ptep = huge_pte_offset(mm, address); 2101 if (!ptep) 2102 continue; 2103 if (huge_pmd_unshare(mm, &address, ptep)) 2104 continue; 2105 if (!huge_pte_none(huge_ptep_get(ptep))) { 2106 pte = huge_ptep_get_and_clear(mm, address, ptep); 2107 pte = pte_mkhuge(pte_modify(pte, newprot)); 2108 set_huge_pte_at(mm, address, ptep, pte); 2109 } 2110 } 2111 spin_unlock(&mm->page_table_lock); 2112 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2113 2114 flush_tlb_range(vma, start, end); 2115} 2116 2117int hugetlb_reserve_pages(struct inode *inode, 2118 long from, long to, 2119 struct vm_area_struct *vma) 2120{ 2121 long ret, chg; 2122 struct hstate *h = hstate_inode(inode); 2123 2124 if (vma && vma->vm_flags & VM_NORESERVE) 2125 return 0; 2126 2127 /* 2128 * Shared mappings base their reservation on the number of pages that 2129 * are already allocated on behalf of the file. Private mappings need 2130 * to reserve the full area even if read-only as mprotect() may be 2131 * called to make the mapping read-write. Assume !vma is a shm mapping 2132 */ 2133 if (!vma || vma->vm_flags & VM_SHARED) 2134 chg = region_chg(&inode->i_mapping->private_list, from, to); 2135 else { 2136 struct resv_map *resv_map = resv_map_alloc(); 2137 if (!resv_map) 2138 return -ENOMEM; 2139 2140 chg = to - from; 2141 2142 set_vma_resv_map(vma, resv_map); 2143 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 2144 } 2145 2146 if (chg < 0) 2147 return chg; 2148 2149 if (hugetlb_get_quota(inode->i_mapping, chg)) 2150 return -ENOSPC; 2151 ret = hugetlb_acct_memory(h, chg); 2152 if (ret < 0) { 2153 hugetlb_put_quota(inode->i_mapping, chg); 2154 return ret; 2155 } 2156 if (!vma || vma->vm_flags & VM_SHARED) 2157 region_add(&inode->i_mapping->private_list, from, to); 2158 return 0; 2159} 2160 2161void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 2162{ 2163 struct hstate *h = hstate_inode(inode); 2164 long chg = region_truncate(&inode->i_mapping->private_list, offset); 2165 2166 spin_lock(&inode->i_lock); 2167 inode->i_blocks -= blocks_per_huge_page(h); 2168 spin_unlock(&inode->i_lock); 2169 2170 hugetlb_put_quota(inode->i_mapping, (chg - freed)); 2171 hugetlb_acct_memory(h, -(chg - freed)); 2172} 2173