hugetlb.c revision b4d1d99fdd8b98fb03dfd6ef9b0ece220de38640
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/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 21#include <asm/page.h> 22#include <asm/pgtable.h> 23#include <asm/io.h> 24 25#include <linux/hugetlb.h> 26#include "internal.h" 27 28const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 29static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 30unsigned long hugepages_treat_as_movable; 31 32static int max_hstate; 33unsigned int default_hstate_idx; 34struct hstate hstates[HUGE_MAX_HSTATE]; 35 36__initdata LIST_HEAD(huge_boot_pages); 37 38/* for command line parsing */ 39static struct hstate * __initdata parsed_hstate; 40static unsigned long __initdata default_hstate_max_huge_pages; 41static unsigned long __initdata default_hstate_size; 42 43#define for_each_hstate(h) \ 44 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) 45 46/* 47 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages 48 */ 49static DEFINE_SPINLOCK(hugetlb_lock); 50 51/* 52 * Region tracking -- allows tracking of reservations and instantiated pages 53 * across the pages in a mapping. 54 * 55 * The region data structures are protected by a combination of the mmap_sem 56 * and the hugetlb_instantion_mutex. To access or modify a region the caller 57 * must either hold the mmap_sem for write, or the mmap_sem for read and 58 * the hugetlb_instantiation mutex: 59 * 60 * down_write(&mm->mmap_sem); 61 * or 62 * down_read(&mm->mmap_sem); 63 * mutex_lock(&hugetlb_instantiation_mutex); 64 */ 65struct file_region { 66 struct list_head link; 67 long from; 68 long to; 69}; 70 71static long region_add(struct list_head *head, long f, long t) 72{ 73 struct file_region *rg, *nrg, *trg; 74 75 /* Locate the region we are either in or before. */ 76 list_for_each_entry(rg, head, link) 77 if (f <= rg->to) 78 break; 79 80 /* Round our left edge to the current segment if it encloses us. */ 81 if (f > rg->from) 82 f = rg->from; 83 84 /* Check for and consume any regions we now overlap with. */ 85 nrg = rg; 86 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 87 if (&rg->link == head) 88 break; 89 if (rg->from > t) 90 break; 91 92 /* If this area reaches higher then extend our area to 93 * include it completely. If this is not the first area 94 * which we intend to reuse, free it. */ 95 if (rg->to > t) 96 t = rg->to; 97 if (rg != nrg) { 98 list_del(&rg->link); 99 kfree(rg); 100 } 101 } 102 nrg->from = f; 103 nrg->to = t; 104 return 0; 105} 106 107static long region_chg(struct list_head *head, long f, long t) 108{ 109 struct file_region *rg, *nrg; 110 long chg = 0; 111 112 /* Locate the region we are before or in. */ 113 list_for_each_entry(rg, head, link) 114 if (f <= rg->to) 115 break; 116 117 /* If we are below the current region then a new region is required. 118 * Subtle, allocate a new region at the position but make it zero 119 * size such that we can guarantee to record the reservation. */ 120 if (&rg->link == head || t < rg->from) { 121 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 122 if (!nrg) 123 return -ENOMEM; 124 nrg->from = f; 125 nrg->to = f; 126 INIT_LIST_HEAD(&nrg->link); 127 list_add(&nrg->link, rg->link.prev); 128 129 return t - f; 130 } 131 132 /* Round our left edge to the current segment if it encloses us. */ 133 if (f > rg->from) 134 f = rg->from; 135 chg = t - f; 136 137 /* Check for and consume any regions we now overlap with. */ 138 list_for_each_entry(rg, rg->link.prev, link) { 139 if (&rg->link == head) 140 break; 141 if (rg->from > t) 142 return chg; 143 144 /* We overlap with this area, if it extends futher than 145 * us then we must extend ourselves. Account for its 146 * existing reservation. */ 147 if (rg->to > t) { 148 chg += rg->to - t; 149 t = rg->to; 150 } 151 chg -= rg->to - rg->from; 152 } 153 return chg; 154} 155 156static long region_truncate(struct list_head *head, long end) 157{ 158 struct file_region *rg, *trg; 159 long chg = 0; 160 161 /* Locate the region we are either in or before. */ 162 list_for_each_entry(rg, head, link) 163 if (end <= rg->to) 164 break; 165 if (&rg->link == head) 166 return 0; 167 168 /* If we are in the middle of a region then adjust it. */ 169 if (end > rg->from) { 170 chg = rg->to - end; 171 rg->to = end; 172 rg = list_entry(rg->link.next, typeof(*rg), link); 173 } 174 175 /* Drop any remaining regions. */ 176 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 177 if (&rg->link == head) 178 break; 179 chg += rg->to - rg->from; 180 list_del(&rg->link); 181 kfree(rg); 182 } 183 return chg; 184} 185 186static long region_count(struct list_head *head, long f, long t) 187{ 188 struct file_region *rg; 189 long chg = 0; 190 191 /* Locate each segment we overlap with, and count that overlap. */ 192 list_for_each_entry(rg, head, link) { 193 int seg_from; 194 int seg_to; 195 196 if (rg->to <= f) 197 continue; 198 if (rg->from >= t) 199 break; 200 201 seg_from = max(rg->from, f); 202 seg_to = min(rg->to, t); 203 204 chg += seg_to - seg_from; 205 } 206 207 return chg; 208} 209 210/* 211 * Convert the address within this vma to the page offset within 212 * the mapping, in pagecache page units; huge pages here. 213 */ 214static pgoff_t vma_hugecache_offset(struct hstate *h, 215 struct vm_area_struct *vma, unsigned long address) 216{ 217 return ((address - vma->vm_start) >> huge_page_shift(h)) + 218 (vma->vm_pgoff >> huge_page_order(h)); 219} 220 221/* 222 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 223 * bits of the reservation map pointer, which are always clear due to 224 * alignment. 225 */ 226#define HPAGE_RESV_OWNER (1UL << 0) 227#define HPAGE_RESV_UNMAPPED (1UL << 1) 228#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 229 230/* 231 * These helpers are used to track how many pages are reserved for 232 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 233 * is guaranteed to have their future faults succeed. 234 * 235 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 236 * the reserve counters are updated with the hugetlb_lock held. It is safe 237 * to reset the VMA at fork() time as it is not in use yet and there is no 238 * chance of the global counters getting corrupted as a result of the values. 239 * 240 * The private mapping reservation is represented in a subtly different 241 * manner to a shared mapping. A shared mapping has a region map associated 242 * with the underlying file, this region map represents the backing file 243 * pages which have ever had a reservation assigned which this persists even 244 * after the page is instantiated. A private mapping has a region map 245 * associated with the original mmap which is attached to all VMAs which 246 * reference it, this region map represents those offsets which have consumed 247 * reservation ie. where pages have been instantiated. 248 */ 249static unsigned long get_vma_private_data(struct vm_area_struct *vma) 250{ 251 return (unsigned long)vma->vm_private_data; 252} 253 254static void set_vma_private_data(struct vm_area_struct *vma, 255 unsigned long value) 256{ 257 vma->vm_private_data = (void *)value; 258} 259 260struct resv_map { 261 struct kref refs; 262 struct list_head regions; 263}; 264 265struct resv_map *resv_map_alloc(void) 266{ 267 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 268 if (!resv_map) 269 return NULL; 270 271 kref_init(&resv_map->refs); 272 INIT_LIST_HEAD(&resv_map->regions); 273 274 return resv_map; 275} 276 277void resv_map_release(struct kref *ref) 278{ 279 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 280 281 /* Clear out any active regions before we release the map. */ 282 region_truncate(&resv_map->regions, 0); 283 kfree(resv_map); 284} 285 286static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 287{ 288 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 289 if (!(vma->vm_flags & VM_SHARED)) 290 return (struct resv_map *)(get_vma_private_data(vma) & 291 ~HPAGE_RESV_MASK); 292 return 0; 293} 294 295static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 296{ 297 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 298 VM_BUG_ON(vma->vm_flags & VM_SHARED); 299 300 set_vma_private_data(vma, (get_vma_private_data(vma) & 301 HPAGE_RESV_MASK) | (unsigned long)map); 302} 303 304static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 305{ 306 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 307 VM_BUG_ON(vma->vm_flags & VM_SHARED); 308 309 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 310} 311 312static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 313{ 314 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 315 316 return (get_vma_private_data(vma) & flag) != 0; 317} 318 319/* Decrement the reserved pages in the hugepage pool by one */ 320static void decrement_hugepage_resv_vma(struct hstate *h, 321 struct vm_area_struct *vma) 322{ 323 if (vma->vm_flags & VM_NORESERVE) 324 return; 325 326 if (vma->vm_flags & VM_SHARED) { 327 /* Shared mappings always use reserves */ 328 h->resv_huge_pages--; 329 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 330 /* 331 * Only the process that called mmap() has reserves for 332 * private mappings. 333 */ 334 h->resv_huge_pages--; 335 } 336} 337 338/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 339void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 340{ 341 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 342 if (!(vma->vm_flags & VM_SHARED)) 343 vma->vm_private_data = (void *)0; 344} 345 346/* Returns true if the VMA has associated reserve pages */ 347static int vma_has_reserves(struct vm_area_struct *vma) 348{ 349 if (vma->vm_flags & VM_SHARED) 350 return 1; 351 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 352 return 1; 353 return 0; 354} 355 356static void clear_huge_page(struct page *page, 357 unsigned long addr, unsigned long sz) 358{ 359 int i; 360 361 might_sleep(); 362 for (i = 0; i < sz/PAGE_SIZE; i++) { 363 cond_resched(); 364 clear_user_highpage(page + i, addr + i * PAGE_SIZE); 365 } 366} 367 368static void copy_huge_page(struct page *dst, struct page *src, 369 unsigned long addr, struct vm_area_struct *vma) 370{ 371 int i; 372 struct hstate *h = hstate_vma(vma); 373 374 might_sleep(); 375 for (i = 0; i < pages_per_huge_page(h); i++) { 376 cond_resched(); 377 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); 378 } 379} 380 381static void enqueue_huge_page(struct hstate *h, struct page *page) 382{ 383 int nid = page_to_nid(page); 384 list_add(&page->lru, &h->hugepage_freelists[nid]); 385 h->free_huge_pages++; 386 h->free_huge_pages_node[nid]++; 387} 388 389static struct page *dequeue_huge_page(struct hstate *h) 390{ 391 int nid; 392 struct page *page = NULL; 393 394 for (nid = 0; nid < MAX_NUMNODES; ++nid) { 395 if (!list_empty(&h->hugepage_freelists[nid])) { 396 page = list_entry(h->hugepage_freelists[nid].next, 397 struct page, lru); 398 list_del(&page->lru); 399 h->free_huge_pages--; 400 h->free_huge_pages_node[nid]--; 401 break; 402 } 403 } 404 return page; 405} 406 407static struct page *dequeue_huge_page_vma(struct hstate *h, 408 struct vm_area_struct *vma, 409 unsigned long address, int avoid_reserve) 410{ 411 int nid; 412 struct page *page = NULL; 413 struct mempolicy *mpol; 414 nodemask_t *nodemask; 415 struct zonelist *zonelist = huge_zonelist(vma, address, 416 htlb_alloc_mask, &mpol, &nodemask); 417 struct zone *zone; 418 struct zoneref *z; 419 420 /* 421 * A child process with MAP_PRIVATE mappings created by their parent 422 * have no page reserves. This check ensures that reservations are 423 * not "stolen". The child may still get SIGKILLed 424 */ 425 if (!vma_has_reserves(vma) && 426 h->free_huge_pages - h->resv_huge_pages == 0) 427 return NULL; 428 429 /* If reserves cannot be used, ensure enough pages are in the pool */ 430 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 431 return NULL; 432 433 for_each_zone_zonelist_nodemask(zone, z, zonelist, 434 MAX_NR_ZONES - 1, nodemask) { 435 nid = zone_to_nid(zone); 436 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && 437 !list_empty(&h->hugepage_freelists[nid])) { 438 page = list_entry(h->hugepage_freelists[nid].next, 439 struct page, lru); 440 list_del(&page->lru); 441 h->free_huge_pages--; 442 h->free_huge_pages_node[nid]--; 443 444 if (!avoid_reserve) 445 decrement_hugepage_resv_vma(h, vma); 446 447 break; 448 } 449 } 450 mpol_cond_put(mpol); 451 return page; 452} 453 454static void update_and_free_page(struct hstate *h, struct page *page) 455{ 456 int i; 457 458 h->nr_huge_pages--; 459 h->nr_huge_pages_node[page_to_nid(page)]--; 460 for (i = 0; i < pages_per_huge_page(h); i++) { 461 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 462 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 463 1 << PG_private | 1<< PG_writeback); 464 } 465 set_compound_page_dtor(page, NULL); 466 set_page_refcounted(page); 467 arch_release_hugepage(page); 468 __free_pages(page, huge_page_order(h)); 469} 470 471struct hstate *size_to_hstate(unsigned long size) 472{ 473 struct hstate *h; 474 475 for_each_hstate(h) { 476 if (huge_page_size(h) == size) 477 return h; 478 } 479 return NULL; 480} 481 482static void free_huge_page(struct page *page) 483{ 484 /* 485 * Can't pass hstate in here because it is called from the 486 * compound page destructor. 487 */ 488 struct hstate *h = page_hstate(page); 489 int nid = page_to_nid(page); 490 struct address_space *mapping; 491 492 mapping = (struct address_space *) page_private(page); 493 set_page_private(page, 0); 494 BUG_ON(page_count(page)); 495 INIT_LIST_HEAD(&page->lru); 496 497 spin_lock(&hugetlb_lock); 498 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 499 update_and_free_page(h, page); 500 h->surplus_huge_pages--; 501 h->surplus_huge_pages_node[nid]--; 502 } else { 503 enqueue_huge_page(h, page); 504 } 505 spin_unlock(&hugetlb_lock); 506 if (mapping) 507 hugetlb_put_quota(mapping, 1); 508} 509 510/* 511 * Increment or decrement surplus_huge_pages. Keep node-specific counters 512 * balanced by operating on them in a round-robin fashion. 513 * Returns 1 if an adjustment was made. 514 */ 515static int adjust_pool_surplus(struct hstate *h, int delta) 516{ 517 static int prev_nid; 518 int nid = prev_nid; 519 int ret = 0; 520 521 VM_BUG_ON(delta != -1 && delta != 1); 522 do { 523 nid = next_node(nid, node_online_map); 524 if (nid == MAX_NUMNODES) 525 nid = first_node(node_online_map); 526 527 /* To shrink on this node, there must be a surplus page */ 528 if (delta < 0 && !h->surplus_huge_pages_node[nid]) 529 continue; 530 /* Surplus cannot exceed the total number of pages */ 531 if (delta > 0 && h->surplus_huge_pages_node[nid] >= 532 h->nr_huge_pages_node[nid]) 533 continue; 534 535 h->surplus_huge_pages += delta; 536 h->surplus_huge_pages_node[nid] += delta; 537 ret = 1; 538 break; 539 } while (nid != prev_nid); 540 541 prev_nid = nid; 542 return ret; 543} 544 545static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 546{ 547 set_compound_page_dtor(page, free_huge_page); 548 spin_lock(&hugetlb_lock); 549 h->nr_huge_pages++; 550 h->nr_huge_pages_node[nid]++; 551 spin_unlock(&hugetlb_lock); 552 put_page(page); /* free it into the hugepage allocator */ 553} 554 555static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 556{ 557 struct page *page; 558 559 if (h->order >= MAX_ORDER) 560 return NULL; 561 562 page = alloc_pages_node(nid, 563 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 564 __GFP_REPEAT|__GFP_NOWARN, 565 huge_page_order(h)); 566 if (page) { 567 if (arch_prepare_hugepage(page)) { 568 __free_pages(page, huge_page_order(h)); 569 return NULL; 570 } 571 prep_new_huge_page(h, page, nid); 572 } 573 574 return page; 575} 576 577/* 578 * Use a helper variable to find the next node and then 579 * copy it back to hugetlb_next_nid afterwards: 580 * otherwise there's a window in which a racer might 581 * pass invalid nid MAX_NUMNODES to alloc_pages_node. 582 * But we don't need to use a spin_lock here: it really 583 * doesn't matter if occasionally a racer chooses the 584 * same nid as we do. Move nid forward in the mask even 585 * if we just successfully allocated a hugepage so that 586 * the next caller gets hugepages on the next node. 587 */ 588static int hstate_next_node(struct hstate *h) 589{ 590 int next_nid; 591 next_nid = next_node(h->hugetlb_next_nid, node_online_map); 592 if (next_nid == MAX_NUMNODES) 593 next_nid = first_node(node_online_map); 594 h->hugetlb_next_nid = next_nid; 595 return next_nid; 596} 597 598static int alloc_fresh_huge_page(struct hstate *h) 599{ 600 struct page *page; 601 int start_nid; 602 int next_nid; 603 int ret = 0; 604 605 start_nid = h->hugetlb_next_nid; 606 607 do { 608 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid); 609 if (page) 610 ret = 1; 611 next_nid = hstate_next_node(h); 612 } while (!page && h->hugetlb_next_nid != start_nid); 613 614 if (ret) 615 count_vm_event(HTLB_BUDDY_PGALLOC); 616 else 617 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 618 619 return ret; 620} 621 622static struct page *alloc_buddy_huge_page(struct hstate *h, 623 struct vm_area_struct *vma, unsigned long address) 624{ 625 struct page *page; 626 unsigned int nid; 627 628 if (h->order >= MAX_ORDER) 629 return NULL; 630 631 /* 632 * Assume we will successfully allocate the surplus page to 633 * prevent racing processes from causing the surplus to exceed 634 * overcommit 635 * 636 * This however introduces a different race, where a process B 637 * tries to grow the static hugepage pool while alloc_pages() is 638 * called by process A. B will only examine the per-node 639 * counters in determining if surplus huge pages can be 640 * converted to normal huge pages in adjust_pool_surplus(). A 641 * won't be able to increment the per-node counter, until the 642 * lock is dropped by B, but B doesn't drop hugetlb_lock until 643 * no more huge pages can be converted from surplus to normal 644 * state (and doesn't try to convert again). Thus, we have a 645 * case where a surplus huge page exists, the pool is grown, and 646 * the surplus huge page still exists after, even though it 647 * should just have been converted to a normal huge page. This 648 * does not leak memory, though, as the hugepage will be freed 649 * once it is out of use. It also does not allow the counters to 650 * go out of whack in adjust_pool_surplus() as we don't modify 651 * the node values until we've gotten the hugepage and only the 652 * per-node value is checked there. 653 */ 654 spin_lock(&hugetlb_lock); 655 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 656 spin_unlock(&hugetlb_lock); 657 return NULL; 658 } else { 659 h->nr_huge_pages++; 660 h->surplus_huge_pages++; 661 } 662 spin_unlock(&hugetlb_lock); 663 664 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 665 __GFP_REPEAT|__GFP_NOWARN, 666 huge_page_order(h)); 667 668 if (page && arch_prepare_hugepage(page)) { 669 __free_pages(page, huge_page_order(h)); 670 return NULL; 671 } 672 673 spin_lock(&hugetlb_lock); 674 if (page) { 675 /* 676 * This page is now managed by the hugetlb allocator and has 677 * no users -- drop the buddy allocator's reference. 678 */ 679 put_page_testzero(page); 680 VM_BUG_ON(page_count(page)); 681 nid = page_to_nid(page); 682 set_compound_page_dtor(page, free_huge_page); 683 /* 684 * We incremented the global counters already 685 */ 686 h->nr_huge_pages_node[nid]++; 687 h->surplus_huge_pages_node[nid]++; 688 __count_vm_event(HTLB_BUDDY_PGALLOC); 689 } else { 690 h->nr_huge_pages--; 691 h->surplus_huge_pages--; 692 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 693 } 694 spin_unlock(&hugetlb_lock); 695 696 return page; 697} 698 699/* 700 * Increase the hugetlb pool such that it can accomodate a reservation 701 * of size 'delta'. 702 */ 703static int gather_surplus_pages(struct hstate *h, int delta) 704{ 705 struct list_head surplus_list; 706 struct page *page, *tmp; 707 int ret, i; 708 int needed, allocated; 709 710 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 711 if (needed <= 0) { 712 h->resv_huge_pages += delta; 713 return 0; 714 } 715 716 allocated = 0; 717 INIT_LIST_HEAD(&surplus_list); 718 719 ret = -ENOMEM; 720retry: 721 spin_unlock(&hugetlb_lock); 722 for (i = 0; i < needed; i++) { 723 page = alloc_buddy_huge_page(h, NULL, 0); 724 if (!page) { 725 /* 726 * We were not able to allocate enough pages to 727 * satisfy the entire reservation so we free what 728 * we've allocated so far. 729 */ 730 spin_lock(&hugetlb_lock); 731 needed = 0; 732 goto free; 733 } 734 735 list_add(&page->lru, &surplus_list); 736 } 737 allocated += needed; 738 739 /* 740 * After retaking hugetlb_lock, we need to recalculate 'needed' 741 * because either resv_huge_pages or free_huge_pages may have changed. 742 */ 743 spin_lock(&hugetlb_lock); 744 needed = (h->resv_huge_pages + delta) - 745 (h->free_huge_pages + allocated); 746 if (needed > 0) 747 goto retry; 748 749 /* 750 * The surplus_list now contains _at_least_ the number of extra pages 751 * needed to accomodate the reservation. Add the appropriate number 752 * of pages to the hugetlb pool and free the extras back to the buddy 753 * allocator. Commit the entire reservation here to prevent another 754 * process from stealing the pages as they are added to the pool but 755 * before they are reserved. 756 */ 757 needed += allocated; 758 h->resv_huge_pages += delta; 759 ret = 0; 760free: 761 /* Free the needed pages to the hugetlb pool */ 762 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 763 if ((--needed) < 0) 764 break; 765 list_del(&page->lru); 766 enqueue_huge_page(h, page); 767 } 768 769 /* Free unnecessary surplus pages to the buddy allocator */ 770 if (!list_empty(&surplus_list)) { 771 spin_unlock(&hugetlb_lock); 772 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 773 list_del(&page->lru); 774 /* 775 * The page has a reference count of zero already, so 776 * call free_huge_page directly instead of using 777 * put_page. This must be done with hugetlb_lock 778 * unlocked which is safe because free_huge_page takes 779 * hugetlb_lock before deciding how to free the page. 780 */ 781 free_huge_page(page); 782 } 783 spin_lock(&hugetlb_lock); 784 } 785 786 return ret; 787} 788 789/* 790 * When releasing a hugetlb pool reservation, any surplus pages that were 791 * allocated to satisfy the reservation must be explicitly freed if they were 792 * never used. 793 */ 794static void return_unused_surplus_pages(struct hstate *h, 795 unsigned long unused_resv_pages) 796{ 797 static int nid = -1; 798 struct page *page; 799 unsigned long nr_pages; 800 801 /* 802 * We want to release as many surplus pages as possible, spread 803 * evenly across all nodes. Iterate across all nodes until we 804 * can no longer free unreserved surplus pages. This occurs when 805 * the nodes with surplus pages have no free pages. 806 */ 807 unsigned long remaining_iterations = num_online_nodes(); 808 809 /* Uncommit the reservation */ 810 h->resv_huge_pages -= unused_resv_pages; 811 812 /* Cannot return gigantic pages currently */ 813 if (h->order >= MAX_ORDER) 814 return; 815 816 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 817 818 while (remaining_iterations-- && nr_pages) { 819 nid = next_node(nid, node_online_map); 820 if (nid == MAX_NUMNODES) 821 nid = first_node(node_online_map); 822 823 if (!h->surplus_huge_pages_node[nid]) 824 continue; 825 826 if (!list_empty(&h->hugepage_freelists[nid])) { 827 page = list_entry(h->hugepage_freelists[nid].next, 828 struct page, lru); 829 list_del(&page->lru); 830 update_and_free_page(h, page); 831 h->free_huge_pages--; 832 h->free_huge_pages_node[nid]--; 833 h->surplus_huge_pages--; 834 h->surplus_huge_pages_node[nid]--; 835 nr_pages--; 836 remaining_iterations = num_online_nodes(); 837 } 838 } 839} 840 841/* 842 * Determine if the huge page at addr within the vma has an associated 843 * reservation. Where it does not we will need to logically increase 844 * reservation and actually increase quota before an allocation can occur. 845 * Where any new reservation would be required the reservation change is 846 * prepared, but not committed. Once the page has been quota'd allocated 847 * an instantiated the change should be committed via vma_commit_reservation. 848 * No action is required on failure. 849 */ 850static int vma_needs_reservation(struct hstate *h, 851 struct vm_area_struct *vma, unsigned long addr) 852{ 853 struct address_space *mapping = vma->vm_file->f_mapping; 854 struct inode *inode = mapping->host; 855 856 if (vma->vm_flags & VM_SHARED) { 857 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 858 return region_chg(&inode->i_mapping->private_list, 859 idx, idx + 1); 860 861 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 862 return 1; 863 864 } else { 865 int err; 866 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 867 struct resv_map *reservations = vma_resv_map(vma); 868 869 err = region_chg(&reservations->regions, idx, idx + 1); 870 if (err < 0) 871 return err; 872 return 0; 873 } 874} 875static void vma_commit_reservation(struct hstate *h, 876 struct vm_area_struct *vma, unsigned long addr) 877{ 878 struct address_space *mapping = vma->vm_file->f_mapping; 879 struct inode *inode = mapping->host; 880 881 if (vma->vm_flags & VM_SHARED) { 882 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 883 region_add(&inode->i_mapping->private_list, idx, idx + 1); 884 885 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 886 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 887 struct resv_map *reservations = vma_resv_map(vma); 888 889 /* Mark this page used in the map. */ 890 region_add(&reservations->regions, idx, idx + 1); 891 } 892} 893 894static struct page *alloc_huge_page(struct vm_area_struct *vma, 895 unsigned long addr, int avoid_reserve) 896{ 897 struct hstate *h = hstate_vma(vma); 898 struct page *page; 899 struct address_space *mapping = vma->vm_file->f_mapping; 900 struct inode *inode = mapping->host; 901 unsigned int chg; 902 903 /* 904 * Processes that did not create the mapping will have no reserves and 905 * will not have accounted against quota. Check that the quota can be 906 * made before satisfying the allocation 907 * MAP_NORESERVE mappings may also need pages and quota allocated 908 * if no reserve mapping overlaps. 909 */ 910 chg = vma_needs_reservation(h, vma, addr); 911 if (chg < 0) 912 return ERR_PTR(chg); 913 if (chg) 914 if (hugetlb_get_quota(inode->i_mapping, chg)) 915 return ERR_PTR(-ENOSPC); 916 917 spin_lock(&hugetlb_lock); 918 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 919 spin_unlock(&hugetlb_lock); 920 921 if (!page) { 922 page = alloc_buddy_huge_page(h, vma, addr); 923 if (!page) { 924 hugetlb_put_quota(inode->i_mapping, chg); 925 return ERR_PTR(-VM_FAULT_OOM); 926 } 927 } 928 929 set_page_refcounted(page); 930 set_page_private(page, (unsigned long) mapping); 931 932 vma_commit_reservation(h, vma, addr); 933 934 return page; 935} 936 937__attribute__((weak)) int alloc_bootmem_huge_page(struct hstate *h) 938{ 939 struct huge_bootmem_page *m; 940 int nr_nodes = nodes_weight(node_online_map); 941 942 while (nr_nodes) { 943 void *addr; 944 945 addr = __alloc_bootmem_node_nopanic( 946 NODE_DATA(h->hugetlb_next_nid), 947 huge_page_size(h), huge_page_size(h), 0); 948 949 if (addr) { 950 /* 951 * Use the beginning of the huge page to store the 952 * huge_bootmem_page struct (until gather_bootmem 953 * puts them into the mem_map). 954 */ 955 m = addr; 956 if (m) 957 goto found; 958 } 959 hstate_next_node(h); 960 nr_nodes--; 961 } 962 return 0; 963 964found: 965 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 966 /* Put them into a private list first because mem_map is not up yet */ 967 list_add(&m->list, &huge_boot_pages); 968 m->hstate = h; 969 return 1; 970} 971 972/* Put bootmem huge pages into the standard lists after mem_map is up */ 973static void __init gather_bootmem_prealloc(void) 974{ 975 struct huge_bootmem_page *m; 976 977 list_for_each_entry(m, &huge_boot_pages, list) { 978 struct page *page = virt_to_page(m); 979 struct hstate *h = m->hstate; 980 __ClearPageReserved(page); 981 WARN_ON(page_count(page) != 1); 982 prep_compound_page(page, h->order); 983 prep_new_huge_page(h, page, page_to_nid(page)); 984 } 985} 986 987static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 988{ 989 unsigned long i; 990 991 for (i = 0; i < h->max_huge_pages; ++i) { 992 if (h->order >= MAX_ORDER) { 993 if (!alloc_bootmem_huge_page(h)) 994 break; 995 } else if (!alloc_fresh_huge_page(h)) 996 break; 997 } 998 h->max_huge_pages = i; 999} 1000 1001static void __init hugetlb_init_hstates(void) 1002{ 1003 struct hstate *h; 1004 1005 for_each_hstate(h) { 1006 /* oversize hugepages were init'ed in early boot */ 1007 if (h->order < MAX_ORDER) 1008 hugetlb_hstate_alloc_pages(h); 1009 } 1010} 1011 1012static char * __init memfmt(char *buf, unsigned long n) 1013{ 1014 if (n >= (1UL << 30)) 1015 sprintf(buf, "%lu GB", n >> 30); 1016 else if (n >= (1UL << 20)) 1017 sprintf(buf, "%lu MB", n >> 20); 1018 else 1019 sprintf(buf, "%lu KB", n >> 10); 1020 return buf; 1021} 1022 1023static void __init report_hugepages(void) 1024{ 1025 struct hstate *h; 1026 1027 for_each_hstate(h) { 1028 char buf[32]; 1029 printk(KERN_INFO "HugeTLB registered %s page size, " 1030 "pre-allocated %ld pages\n", 1031 memfmt(buf, huge_page_size(h)), 1032 h->free_huge_pages); 1033 } 1034} 1035 1036#ifdef CONFIG_HIGHMEM 1037static void try_to_free_low(struct hstate *h, unsigned long count) 1038{ 1039 int i; 1040 1041 if (h->order >= MAX_ORDER) 1042 return; 1043 1044 for (i = 0; i < MAX_NUMNODES; ++i) { 1045 struct page *page, *next; 1046 struct list_head *freel = &h->hugepage_freelists[i]; 1047 list_for_each_entry_safe(page, next, freel, lru) { 1048 if (count >= h->nr_huge_pages) 1049 return; 1050 if (PageHighMem(page)) 1051 continue; 1052 list_del(&page->lru); 1053 update_and_free_page(h, page); 1054 h->free_huge_pages--; 1055 h->free_huge_pages_node[page_to_nid(page)]--; 1056 } 1057 } 1058} 1059#else 1060static inline void try_to_free_low(struct hstate *h, unsigned long count) 1061{ 1062} 1063#endif 1064 1065#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1066static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count) 1067{ 1068 unsigned long min_count, ret; 1069 1070 if (h->order >= MAX_ORDER) 1071 return h->max_huge_pages; 1072 1073 /* 1074 * Increase the pool size 1075 * First take pages out of surplus state. Then make up the 1076 * remaining difference by allocating fresh huge pages. 1077 * 1078 * We might race with alloc_buddy_huge_page() here and be unable 1079 * to convert a surplus huge page to a normal huge page. That is 1080 * not critical, though, it just means the overall size of the 1081 * pool might be one hugepage larger than it needs to be, but 1082 * within all the constraints specified by the sysctls. 1083 */ 1084 spin_lock(&hugetlb_lock); 1085 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1086 if (!adjust_pool_surplus(h, -1)) 1087 break; 1088 } 1089 1090 while (count > persistent_huge_pages(h)) { 1091 /* 1092 * If this allocation races such that we no longer need the 1093 * page, free_huge_page will handle it by freeing the page 1094 * and reducing the surplus. 1095 */ 1096 spin_unlock(&hugetlb_lock); 1097 ret = alloc_fresh_huge_page(h); 1098 spin_lock(&hugetlb_lock); 1099 if (!ret) 1100 goto out; 1101 1102 } 1103 1104 /* 1105 * Decrease the pool size 1106 * First return free pages to the buddy allocator (being careful 1107 * to keep enough around to satisfy reservations). Then place 1108 * pages into surplus state as needed so the pool will shrink 1109 * to the desired size as pages become free. 1110 * 1111 * By placing pages into the surplus state independent of the 1112 * overcommit value, we are allowing the surplus pool size to 1113 * exceed overcommit. There are few sane options here. Since 1114 * alloc_buddy_huge_page() is checking the global counter, 1115 * though, we'll note that we're not allowed to exceed surplus 1116 * and won't grow the pool anywhere else. Not until one of the 1117 * sysctls are changed, or the surplus pages go out of use. 1118 */ 1119 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1120 min_count = max(count, min_count); 1121 try_to_free_low(h, min_count); 1122 while (min_count < persistent_huge_pages(h)) { 1123 struct page *page = dequeue_huge_page(h); 1124 if (!page) 1125 break; 1126 update_and_free_page(h, page); 1127 } 1128 while (count < persistent_huge_pages(h)) { 1129 if (!adjust_pool_surplus(h, 1)) 1130 break; 1131 } 1132out: 1133 ret = persistent_huge_pages(h); 1134 spin_unlock(&hugetlb_lock); 1135 return ret; 1136} 1137 1138#define HSTATE_ATTR_RO(_name) \ 1139 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1140 1141#define HSTATE_ATTR(_name) \ 1142 static struct kobj_attribute _name##_attr = \ 1143 __ATTR(_name, 0644, _name##_show, _name##_store) 1144 1145static struct kobject *hugepages_kobj; 1146static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1147 1148static struct hstate *kobj_to_hstate(struct kobject *kobj) 1149{ 1150 int i; 1151 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1152 if (hstate_kobjs[i] == kobj) 1153 return &hstates[i]; 1154 BUG(); 1155 return NULL; 1156} 1157 1158static ssize_t nr_hugepages_show(struct kobject *kobj, 1159 struct kobj_attribute *attr, char *buf) 1160{ 1161 struct hstate *h = kobj_to_hstate(kobj); 1162 return sprintf(buf, "%lu\n", h->nr_huge_pages); 1163} 1164static ssize_t nr_hugepages_store(struct kobject *kobj, 1165 struct kobj_attribute *attr, const char *buf, size_t count) 1166{ 1167 int err; 1168 unsigned long input; 1169 struct hstate *h = kobj_to_hstate(kobj); 1170 1171 err = strict_strtoul(buf, 10, &input); 1172 if (err) 1173 return 0; 1174 1175 h->max_huge_pages = set_max_huge_pages(h, input); 1176 1177 return count; 1178} 1179HSTATE_ATTR(nr_hugepages); 1180 1181static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1182 struct kobj_attribute *attr, char *buf) 1183{ 1184 struct hstate *h = kobj_to_hstate(kobj); 1185 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1186} 1187static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1188 struct kobj_attribute *attr, const char *buf, size_t count) 1189{ 1190 int err; 1191 unsigned long input; 1192 struct hstate *h = kobj_to_hstate(kobj); 1193 1194 err = strict_strtoul(buf, 10, &input); 1195 if (err) 1196 return 0; 1197 1198 spin_lock(&hugetlb_lock); 1199 h->nr_overcommit_huge_pages = input; 1200 spin_unlock(&hugetlb_lock); 1201 1202 return count; 1203} 1204HSTATE_ATTR(nr_overcommit_hugepages); 1205 1206static ssize_t free_hugepages_show(struct kobject *kobj, 1207 struct kobj_attribute *attr, char *buf) 1208{ 1209 struct hstate *h = kobj_to_hstate(kobj); 1210 return sprintf(buf, "%lu\n", h->free_huge_pages); 1211} 1212HSTATE_ATTR_RO(free_hugepages); 1213 1214static ssize_t resv_hugepages_show(struct kobject *kobj, 1215 struct kobj_attribute *attr, char *buf) 1216{ 1217 struct hstate *h = kobj_to_hstate(kobj); 1218 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1219} 1220HSTATE_ATTR_RO(resv_hugepages); 1221 1222static ssize_t surplus_hugepages_show(struct kobject *kobj, 1223 struct kobj_attribute *attr, char *buf) 1224{ 1225 struct hstate *h = kobj_to_hstate(kobj); 1226 return sprintf(buf, "%lu\n", h->surplus_huge_pages); 1227} 1228HSTATE_ATTR_RO(surplus_hugepages); 1229 1230static struct attribute *hstate_attrs[] = { 1231 &nr_hugepages_attr.attr, 1232 &nr_overcommit_hugepages_attr.attr, 1233 &free_hugepages_attr.attr, 1234 &resv_hugepages_attr.attr, 1235 &surplus_hugepages_attr.attr, 1236 NULL, 1237}; 1238 1239static struct attribute_group hstate_attr_group = { 1240 .attrs = hstate_attrs, 1241}; 1242 1243static int __init hugetlb_sysfs_add_hstate(struct hstate *h) 1244{ 1245 int retval; 1246 1247 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name, 1248 hugepages_kobj); 1249 if (!hstate_kobjs[h - hstates]) 1250 return -ENOMEM; 1251 1252 retval = sysfs_create_group(hstate_kobjs[h - hstates], 1253 &hstate_attr_group); 1254 if (retval) 1255 kobject_put(hstate_kobjs[h - hstates]); 1256 1257 return retval; 1258} 1259 1260static void __init hugetlb_sysfs_init(void) 1261{ 1262 struct hstate *h; 1263 int err; 1264 1265 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1266 if (!hugepages_kobj) 1267 return; 1268 1269 for_each_hstate(h) { 1270 err = hugetlb_sysfs_add_hstate(h); 1271 if (err) 1272 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1273 h->name); 1274 } 1275} 1276 1277static void __exit hugetlb_exit(void) 1278{ 1279 struct hstate *h; 1280 1281 for_each_hstate(h) { 1282 kobject_put(hstate_kobjs[h - hstates]); 1283 } 1284 1285 kobject_put(hugepages_kobj); 1286} 1287module_exit(hugetlb_exit); 1288 1289static int __init hugetlb_init(void) 1290{ 1291 /* Some platform decide whether they support huge pages at boot 1292 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1293 * there is no such support 1294 */ 1295 if (HPAGE_SHIFT == 0) 1296 return 0; 1297 1298 if (!size_to_hstate(default_hstate_size)) { 1299 default_hstate_size = HPAGE_SIZE; 1300 if (!size_to_hstate(default_hstate_size)) 1301 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1302 } 1303 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; 1304 if (default_hstate_max_huge_pages) 1305 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1306 1307 hugetlb_init_hstates(); 1308 1309 gather_bootmem_prealloc(); 1310 1311 report_hugepages(); 1312 1313 hugetlb_sysfs_init(); 1314 1315 return 0; 1316} 1317module_init(hugetlb_init); 1318 1319/* Should be called on processing a hugepagesz=... option */ 1320void __init hugetlb_add_hstate(unsigned order) 1321{ 1322 struct hstate *h; 1323 unsigned long i; 1324 1325 if (size_to_hstate(PAGE_SIZE << order)) { 1326 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1327 return; 1328 } 1329 BUG_ON(max_hstate >= HUGE_MAX_HSTATE); 1330 BUG_ON(order == 0); 1331 h = &hstates[max_hstate++]; 1332 h->order = order; 1333 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1334 h->nr_huge_pages = 0; 1335 h->free_huge_pages = 0; 1336 for (i = 0; i < MAX_NUMNODES; ++i) 1337 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1338 h->hugetlb_next_nid = first_node(node_online_map); 1339 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1340 huge_page_size(h)/1024); 1341 1342 parsed_hstate = h; 1343} 1344 1345static int __init hugetlb_nrpages_setup(char *s) 1346{ 1347 unsigned long *mhp; 1348 static unsigned long *last_mhp; 1349 1350 /* 1351 * !max_hstate means we haven't parsed a hugepagesz= parameter yet, 1352 * so this hugepages= parameter goes to the "default hstate". 1353 */ 1354 if (!max_hstate) 1355 mhp = &default_hstate_max_huge_pages; 1356 else 1357 mhp = &parsed_hstate->max_huge_pages; 1358 1359 if (mhp == last_mhp) { 1360 printk(KERN_WARNING "hugepages= specified twice without " 1361 "interleaving hugepagesz=, ignoring\n"); 1362 return 1; 1363 } 1364 1365 if (sscanf(s, "%lu", mhp) <= 0) 1366 *mhp = 0; 1367 1368 /* 1369 * Global state is always initialized later in hugetlb_init. 1370 * But we need to allocate >= MAX_ORDER hstates here early to still 1371 * use the bootmem allocator. 1372 */ 1373 if (max_hstate && parsed_hstate->order >= MAX_ORDER) 1374 hugetlb_hstate_alloc_pages(parsed_hstate); 1375 1376 last_mhp = mhp; 1377 1378 return 1; 1379} 1380__setup("hugepages=", hugetlb_nrpages_setup); 1381 1382static int __init hugetlb_default_setup(char *s) 1383{ 1384 default_hstate_size = memparse(s, &s); 1385 return 1; 1386} 1387__setup("default_hugepagesz=", hugetlb_default_setup); 1388 1389static unsigned int cpuset_mems_nr(unsigned int *array) 1390{ 1391 int node; 1392 unsigned int nr = 0; 1393 1394 for_each_node_mask(node, cpuset_current_mems_allowed) 1395 nr += array[node]; 1396 1397 return nr; 1398} 1399 1400#ifdef CONFIG_SYSCTL 1401int hugetlb_sysctl_handler(struct ctl_table *table, int write, 1402 struct file *file, void __user *buffer, 1403 size_t *length, loff_t *ppos) 1404{ 1405 struct hstate *h = &default_hstate; 1406 unsigned long tmp; 1407 1408 if (!write) 1409 tmp = h->max_huge_pages; 1410 1411 table->data = &tmp; 1412 table->maxlen = sizeof(unsigned long); 1413 proc_doulongvec_minmax(table, write, file, buffer, length, ppos); 1414 1415 if (write) 1416 h->max_huge_pages = set_max_huge_pages(h, tmp); 1417 1418 return 0; 1419} 1420 1421int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 1422 struct file *file, void __user *buffer, 1423 size_t *length, loff_t *ppos) 1424{ 1425 proc_dointvec(table, write, file, buffer, length, ppos); 1426 if (hugepages_treat_as_movable) 1427 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 1428 else 1429 htlb_alloc_mask = GFP_HIGHUSER; 1430 return 0; 1431} 1432 1433int hugetlb_overcommit_handler(struct ctl_table *table, int write, 1434 struct file *file, void __user *buffer, 1435 size_t *length, loff_t *ppos) 1436{ 1437 struct hstate *h = &default_hstate; 1438 unsigned long tmp; 1439 1440 if (!write) 1441 tmp = h->nr_overcommit_huge_pages; 1442 1443 table->data = &tmp; 1444 table->maxlen = sizeof(unsigned long); 1445 proc_doulongvec_minmax(table, write, file, buffer, length, ppos); 1446 1447 if (write) { 1448 spin_lock(&hugetlb_lock); 1449 h->nr_overcommit_huge_pages = tmp; 1450 spin_unlock(&hugetlb_lock); 1451 } 1452 1453 return 0; 1454} 1455 1456#endif /* CONFIG_SYSCTL */ 1457 1458int hugetlb_report_meminfo(char *buf) 1459{ 1460 struct hstate *h = &default_hstate; 1461 return sprintf(buf, 1462 "HugePages_Total: %5lu\n" 1463 "HugePages_Free: %5lu\n" 1464 "HugePages_Rsvd: %5lu\n" 1465 "HugePages_Surp: %5lu\n" 1466 "Hugepagesize: %5lu kB\n", 1467 h->nr_huge_pages, 1468 h->free_huge_pages, 1469 h->resv_huge_pages, 1470 h->surplus_huge_pages, 1471 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 1472} 1473 1474int hugetlb_report_node_meminfo(int nid, char *buf) 1475{ 1476 struct hstate *h = &default_hstate; 1477 return sprintf(buf, 1478 "Node %d HugePages_Total: %5u\n" 1479 "Node %d HugePages_Free: %5u\n" 1480 "Node %d HugePages_Surp: %5u\n", 1481 nid, h->nr_huge_pages_node[nid], 1482 nid, h->free_huge_pages_node[nid], 1483 nid, h->surplus_huge_pages_node[nid]); 1484} 1485 1486/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 1487unsigned long hugetlb_total_pages(void) 1488{ 1489 struct hstate *h = &default_hstate; 1490 return h->nr_huge_pages * pages_per_huge_page(h); 1491} 1492 1493static int hugetlb_acct_memory(struct hstate *h, long delta) 1494{ 1495 int ret = -ENOMEM; 1496 1497 spin_lock(&hugetlb_lock); 1498 /* 1499 * When cpuset is configured, it breaks the strict hugetlb page 1500 * reservation as the accounting is done on a global variable. Such 1501 * reservation is completely rubbish in the presence of cpuset because 1502 * the reservation is not checked against page availability for the 1503 * current cpuset. Application can still potentially OOM'ed by kernel 1504 * with lack of free htlb page in cpuset that the task is in. 1505 * Attempt to enforce strict accounting with cpuset is almost 1506 * impossible (or too ugly) because cpuset is too fluid that 1507 * task or memory node can be dynamically moved between cpusets. 1508 * 1509 * The change of semantics for shared hugetlb mapping with cpuset is 1510 * undesirable. However, in order to preserve some of the semantics, 1511 * we fall back to check against current free page availability as 1512 * a best attempt and hopefully to minimize the impact of changing 1513 * semantics that cpuset has. 1514 */ 1515 if (delta > 0) { 1516 if (gather_surplus_pages(h, delta) < 0) 1517 goto out; 1518 1519 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 1520 return_unused_surplus_pages(h, delta); 1521 goto out; 1522 } 1523 } 1524 1525 ret = 0; 1526 if (delta < 0) 1527 return_unused_surplus_pages(h, (unsigned long) -delta); 1528 1529out: 1530 spin_unlock(&hugetlb_lock); 1531 return ret; 1532} 1533 1534static void hugetlb_vm_op_open(struct vm_area_struct *vma) 1535{ 1536 struct resv_map *reservations = vma_resv_map(vma); 1537 1538 /* 1539 * This new VMA should share its siblings reservation map if present. 1540 * The VMA will only ever have a valid reservation map pointer where 1541 * it is being copied for another still existing VMA. As that VMA 1542 * has a reference to the reservation map it cannot dissappear until 1543 * after this open call completes. It is therefore safe to take a 1544 * new reference here without additional locking. 1545 */ 1546 if (reservations) 1547 kref_get(&reservations->refs); 1548} 1549 1550static void hugetlb_vm_op_close(struct vm_area_struct *vma) 1551{ 1552 struct hstate *h = hstate_vma(vma); 1553 struct resv_map *reservations = vma_resv_map(vma); 1554 unsigned long reserve; 1555 unsigned long start; 1556 unsigned long end; 1557 1558 if (reservations) { 1559 start = vma_hugecache_offset(h, vma, vma->vm_start); 1560 end = vma_hugecache_offset(h, vma, vma->vm_end); 1561 1562 reserve = (end - start) - 1563 region_count(&reservations->regions, start, end); 1564 1565 kref_put(&reservations->refs, resv_map_release); 1566 1567 if (reserve) { 1568 hugetlb_acct_memory(h, -reserve); 1569 hugetlb_put_quota(vma->vm_file->f_mapping, reserve); 1570 } 1571 } 1572} 1573 1574/* 1575 * We cannot handle pagefaults against hugetlb pages at all. They cause 1576 * handle_mm_fault() to try to instantiate regular-sized pages in the 1577 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 1578 * this far. 1579 */ 1580static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 1581{ 1582 BUG(); 1583 return 0; 1584} 1585 1586struct vm_operations_struct hugetlb_vm_ops = { 1587 .fault = hugetlb_vm_op_fault, 1588 .open = hugetlb_vm_op_open, 1589 .close = hugetlb_vm_op_close, 1590}; 1591 1592static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 1593 int writable) 1594{ 1595 pte_t entry; 1596 1597 if (writable) { 1598 entry = 1599 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 1600 } else { 1601 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 1602 } 1603 entry = pte_mkyoung(entry); 1604 entry = pte_mkhuge(entry); 1605 1606 return entry; 1607} 1608 1609static void set_huge_ptep_writable(struct vm_area_struct *vma, 1610 unsigned long address, pte_t *ptep) 1611{ 1612 pte_t entry; 1613 1614 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 1615 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { 1616 update_mmu_cache(vma, address, entry); 1617 } 1618} 1619 1620 1621int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 1622 struct vm_area_struct *vma) 1623{ 1624 pte_t *src_pte, *dst_pte, entry; 1625 struct page *ptepage; 1626 unsigned long addr; 1627 int cow; 1628 struct hstate *h = hstate_vma(vma); 1629 unsigned long sz = huge_page_size(h); 1630 1631 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 1632 1633 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 1634 src_pte = huge_pte_offset(src, addr); 1635 if (!src_pte) 1636 continue; 1637 dst_pte = huge_pte_alloc(dst, addr, sz); 1638 if (!dst_pte) 1639 goto nomem; 1640 1641 /* If the pagetables are shared don't copy or take references */ 1642 if (dst_pte == src_pte) 1643 continue; 1644 1645 spin_lock(&dst->page_table_lock); 1646 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 1647 if (!huge_pte_none(huge_ptep_get(src_pte))) { 1648 if (cow) 1649 huge_ptep_set_wrprotect(src, addr, src_pte); 1650 entry = huge_ptep_get(src_pte); 1651 ptepage = pte_page(entry); 1652 get_page(ptepage); 1653 set_huge_pte_at(dst, addr, dst_pte, entry); 1654 } 1655 spin_unlock(&src->page_table_lock); 1656 spin_unlock(&dst->page_table_lock); 1657 } 1658 return 0; 1659 1660nomem: 1661 return -ENOMEM; 1662} 1663 1664void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 1665 unsigned long end, struct page *ref_page) 1666{ 1667 struct mm_struct *mm = vma->vm_mm; 1668 unsigned long address; 1669 pte_t *ptep; 1670 pte_t pte; 1671 struct page *page; 1672 struct page *tmp; 1673 struct hstate *h = hstate_vma(vma); 1674 unsigned long sz = huge_page_size(h); 1675 1676 /* 1677 * A page gathering list, protected by per file i_mmap_lock. The 1678 * lock is used to avoid list corruption from multiple unmapping 1679 * of the same page since we are using page->lru. 1680 */ 1681 LIST_HEAD(page_list); 1682 1683 WARN_ON(!is_vm_hugetlb_page(vma)); 1684 BUG_ON(start & ~huge_page_mask(h)); 1685 BUG_ON(end & ~huge_page_mask(h)); 1686 1687 mmu_notifier_invalidate_range_start(mm, start, end); 1688 spin_lock(&mm->page_table_lock); 1689 for (address = start; address < end; address += sz) { 1690 ptep = huge_pte_offset(mm, address); 1691 if (!ptep) 1692 continue; 1693 1694 if (huge_pmd_unshare(mm, &address, ptep)) 1695 continue; 1696 1697 /* 1698 * If a reference page is supplied, it is because a specific 1699 * page is being unmapped, not a range. Ensure the page we 1700 * are about to unmap is the actual page of interest. 1701 */ 1702 if (ref_page) { 1703 pte = huge_ptep_get(ptep); 1704 if (huge_pte_none(pte)) 1705 continue; 1706 page = pte_page(pte); 1707 if (page != ref_page) 1708 continue; 1709 1710 /* 1711 * Mark the VMA as having unmapped its page so that 1712 * future faults in this VMA will fail rather than 1713 * looking like data was lost 1714 */ 1715 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 1716 } 1717 1718 pte = huge_ptep_get_and_clear(mm, address, ptep); 1719 if (huge_pte_none(pte)) 1720 continue; 1721 1722 page = pte_page(pte); 1723 if (pte_dirty(pte)) 1724 set_page_dirty(page); 1725 list_add(&page->lru, &page_list); 1726 } 1727 spin_unlock(&mm->page_table_lock); 1728 flush_tlb_range(vma, start, end); 1729 mmu_notifier_invalidate_range_end(mm, start, end); 1730 list_for_each_entry_safe(page, tmp, &page_list, lru) { 1731 list_del(&page->lru); 1732 put_page(page); 1733 } 1734} 1735 1736void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 1737 unsigned long end, struct page *ref_page) 1738{ 1739 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 1740 __unmap_hugepage_range(vma, start, end, ref_page); 1741 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 1742} 1743 1744/* 1745 * This is called when the original mapper is failing to COW a MAP_PRIVATE 1746 * mappping it owns the reserve page for. The intention is to unmap the page 1747 * from other VMAs and let the children be SIGKILLed if they are faulting the 1748 * same region. 1749 */ 1750int unmap_ref_private(struct mm_struct *mm, 1751 struct vm_area_struct *vma, 1752 struct page *page, 1753 unsigned long address) 1754{ 1755 struct vm_area_struct *iter_vma; 1756 struct address_space *mapping; 1757 struct prio_tree_iter iter; 1758 pgoff_t pgoff; 1759 1760 /* 1761 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 1762 * from page cache lookup which is in HPAGE_SIZE units. 1763 */ 1764 address = address & huge_page_mask(hstate_vma(vma)); 1765 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) 1766 + (vma->vm_pgoff >> PAGE_SHIFT); 1767 mapping = (struct address_space *)page_private(page); 1768 1769 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { 1770 /* Do not unmap the current VMA */ 1771 if (iter_vma == vma) 1772 continue; 1773 1774 /* 1775 * Unmap the page from other VMAs without their own reserves. 1776 * They get marked to be SIGKILLed if they fault in these 1777 * areas. This is because a future no-page fault on this VMA 1778 * could insert a zeroed page instead of the data existing 1779 * from the time of fork. This would look like data corruption 1780 */ 1781 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 1782 unmap_hugepage_range(iter_vma, 1783 address, address + HPAGE_SIZE, 1784 page); 1785 } 1786 1787 return 1; 1788} 1789 1790static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 1791 unsigned long address, pte_t *ptep, pte_t pte, 1792 struct page *pagecache_page) 1793{ 1794 struct hstate *h = hstate_vma(vma); 1795 struct page *old_page, *new_page; 1796 int avoidcopy; 1797 int outside_reserve = 0; 1798 1799 old_page = pte_page(pte); 1800 1801retry_avoidcopy: 1802 /* If no-one else is actually using this page, avoid the copy 1803 * and just make the page writable */ 1804 avoidcopy = (page_count(old_page) == 1); 1805 if (avoidcopy) { 1806 set_huge_ptep_writable(vma, address, ptep); 1807 return 0; 1808 } 1809 1810 /* 1811 * If the process that created a MAP_PRIVATE mapping is about to 1812 * perform a COW due to a shared page count, attempt to satisfy 1813 * the allocation without using the existing reserves. The pagecache 1814 * page is used to determine if the reserve at this address was 1815 * consumed or not. If reserves were used, a partial faulted mapping 1816 * at the time of fork() could consume its reserves on COW instead 1817 * of the full address range. 1818 */ 1819 if (!(vma->vm_flags & VM_SHARED) && 1820 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 1821 old_page != pagecache_page) 1822 outside_reserve = 1; 1823 1824 page_cache_get(old_page); 1825 new_page = alloc_huge_page(vma, address, outside_reserve); 1826 1827 if (IS_ERR(new_page)) { 1828 page_cache_release(old_page); 1829 1830 /* 1831 * If a process owning a MAP_PRIVATE mapping fails to COW, 1832 * it is due to references held by a child and an insufficient 1833 * huge page pool. To guarantee the original mappers 1834 * reliability, unmap the page from child processes. The child 1835 * may get SIGKILLed if it later faults. 1836 */ 1837 if (outside_reserve) { 1838 BUG_ON(huge_pte_none(pte)); 1839 if (unmap_ref_private(mm, vma, old_page, address)) { 1840 BUG_ON(page_count(old_page) != 1); 1841 BUG_ON(huge_pte_none(pte)); 1842 goto retry_avoidcopy; 1843 } 1844 WARN_ON_ONCE(1); 1845 } 1846 1847 return -PTR_ERR(new_page); 1848 } 1849 1850 spin_unlock(&mm->page_table_lock); 1851 copy_huge_page(new_page, old_page, address, vma); 1852 __SetPageUptodate(new_page); 1853 spin_lock(&mm->page_table_lock); 1854 1855 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 1856 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 1857 /* Break COW */ 1858 huge_ptep_clear_flush(vma, address, ptep); 1859 set_huge_pte_at(mm, address, ptep, 1860 make_huge_pte(vma, new_page, 1)); 1861 /* Make the old page be freed below */ 1862 new_page = old_page; 1863 } 1864 page_cache_release(new_page); 1865 page_cache_release(old_page); 1866 return 0; 1867} 1868 1869/* Return the pagecache page at a given address within a VMA */ 1870static struct page *hugetlbfs_pagecache_page(struct hstate *h, 1871 struct vm_area_struct *vma, unsigned long address) 1872{ 1873 struct address_space *mapping; 1874 pgoff_t idx; 1875 1876 mapping = vma->vm_file->f_mapping; 1877 idx = vma_hugecache_offset(h, vma, address); 1878 1879 return find_lock_page(mapping, idx); 1880} 1881 1882static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 1883 unsigned long address, pte_t *ptep, int write_access) 1884{ 1885 struct hstate *h = hstate_vma(vma); 1886 int ret = VM_FAULT_SIGBUS; 1887 pgoff_t idx; 1888 unsigned long size; 1889 struct page *page; 1890 struct address_space *mapping; 1891 pte_t new_pte; 1892 1893 /* 1894 * Currently, we are forced to kill the process in the event the 1895 * original mapper has unmapped pages from the child due to a failed 1896 * COW. Warn that such a situation has occured as it may not be obvious 1897 */ 1898 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 1899 printk(KERN_WARNING 1900 "PID %d killed due to inadequate hugepage pool\n", 1901 current->pid); 1902 return ret; 1903 } 1904 1905 mapping = vma->vm_file->f_mapping; 1906 idx = vma_hugecache_offset(h, vma, address); 1907 1908 /* 1909 * Use page lock to guard against racing truncation 1910 * before we get page_table_lock. 1911 */ 1912retry: 1913 page = find_lock_page(mapping, idx); 1914 if (!page) { 1915 size = i_size_read(mapping->host) >> huge_page_shift(h); 1916 if (idx >= size) 1917 goto out; 1918 page = alloc_huge_page(vma, address, 0); 1919 if (IS_ERR(page)) { 1920 ret = -PTR_ERR(page); 1921 goto out; 1922 } 1923 clear_huge_page(page, address, huge_page_size(h)); 1924 __SetPageUptodate(page); 1925 1926 if (vma->vm_flags & VM_SHARED) { 1927 int err; 1928 struct inode *inode = mapping->host; 1929 1930 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 1931 if (err) { 1932 put_page(page); 1933 if (err == -EEXIST) 1934 goto retry; 1935 goto out; 1936 } 1937 1938 spin_lock(&inode->i_lock); 1939 inode->i_blocks += blocks_per_huge_page(h); 1940 spin_unlock(&inode->i_lock); 1941 } else 1942 lock_page(page); 1943 } 1944 1945 /* 1946 * If we are going to COW a private mapping later, we examine the 1947 * pending reservations for this page now. This will ensure that 1948 * any allocations necessary to record that reservation occur outside 1949 * the spinlock. 1950 */ 1951 if (write_access && !(vma->vm_flags & VM_SHARED)) 1952 if (vma_needs_reservation(h, vma, address) < 0) { 1953 ret = VM_FAULT_OOM; 1954 goto backout_unlocked; 1955 } 1956 1957 spin_lock(&mm->page_table_lock); 1958 size = i_size_read(mapping->host) >> huge_page_shift(h); 1959 if (idx >= size) 1960 goto backout; 1961 1962 ret = 0; 1963 if (!huge_pte_none(huge_ptep_get(ptep))) 1964 goto backout; 1965 1966 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 1967 && (vma->vm_flags & VM_SHARED))); 1968 set_huge_pte_at(mm, address, ptep, new_pte); 1969 1970 if (write_access && !(vma->vm_flags & VM_SHARED)) { 1971 /* Optimization, do the COW without a second fault */ 1972 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 1973 } 1974 1975 spin_unlock(&mm->page_table_lock); 1976 unlock_page(page); 1977out: 1978 return ret; 1979 1980backout: 1981 spin_unlock(&mm->page_table_lock); 1982backout_unlocked: 1983 unlock_page(page); 1984 put_page(page); 1985 goto out; 1986} 1987 1988int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 1989 unsigned long address, int write_access) 1990{ 1991 pte_t *ptep; 1992 pte_t entry; 1993 int ret; 1994 struct page *pagecache_page = NULL; 1995 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 1996 struct hstate *h = hstate_vma(vma); 1997 1998 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 1999 if (!ptep) 2000 return VM_FAULT_OOM; 2001 2002 /* 2003 * Serialize hugepage allocation and instantiation, so that we don't 2004 * get spurious allocation failures if two CPUs race to instantiate 2005 * the same page in the page cache. 2006 */ 2007 mutex_lock(&hugetlb_instantiation_mutex); 2008 entry = huge_ptep_get(ptep); 2009 if (huge_pte_none(entry)) { 2010 ret = hugetlb_no_page(mm, vma, address, ptep, write_access); 2011 goto out_mutex; 2012 } 2013 2014 ret = 0; 2015 2016 /* 2017 * If we are going to COW the mapping later, we examine the pending 2018 * reservations for this page now. This will ensure that any 2019 * allocations necessary to record that reservation occur outside the 2020 * spinlock. For private mappings, we also lookup the pagecache 2021 * page now as it is used to determine if a reservation has been 2022 * consumed. 2023 */ 2024 if (write_access && !pte_write(entry)) { 2025 if (vma_needs_reservation(h, vma, address) < 0) { 2026 ret = VM_FAULT_OOM; 2027 goto out_mutex; 2028 } 2029 2030 if (!(vma->vm_flags & VM_SHARED)) 2031 pagecache_page = hugetlbfs_pagecache_page(h, 2032 vma, address); 2033 } 2034 2035 spin_lock(&mm->page_table_lock); 2036 /* Check for a racing update before calling hugetlb_cow */ 2037 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2038 goto out_page_table_lock; 2039 2040 2041 if (write_access) { 2042 if (!pte_write(entry)) { 2043 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2044 pagecache_page); 2045 goto out_page_table_lock; 2046 } 2047 entry = pte_mkdirty(entry); 2048 } 2049 entry = pte_mkyoung(entry); 2050 if (huge_ptep_set_access_flags(vma, address, ptep, entry, write_access)) 2051 update_mmu_cache(vma, address, entry); 2052 2053out_page_table_lock: 2054 spin_unlock(&mm->page_table_lock); 2055 2056 if (pagecache_page) { 2057 unlock_page(pagecache_page); 2058 put_page(pagecache_page); 2059 } 2060 2061out_mutex: 2062 mutex_unlock(&hugetlb_instantiation_mutex); 2063 2064 return ret; 2065} 2066 2067/* Can be overriden by architectures */ 2068__attribute__((weak)) struct page * 2069follow_huge_pud(struct mm_struct *mm, unsigned long address, 2070 pud_t *pud, int write) 2071{ 2072 BUG(); 2073 return NULL; 2074} 2075 2076int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2077 struct page **pages, struct vm_area_struct **vmas, 2078 unsigned long *position, int *length, int i, 2079 int write) 2080{ 2081 unsigned long pfn_offset; 2082 unsigned long vaddr = *position; 2083 int remainder = *length; 2084 struct hstate *h = hstate_vma(vma); 2085 2086 spin_lock(&mm->page_table_lock); 2087 while (vaddr < vma->vm_end && remainder) { 2088 pte_t *pte; 2089 struct page *page; 2090 2091 /* 2092 * Some archs (sparc64, sh*) have multiple pte_ts to 2093 * each hugepage. We have to make * sure we get the 2094 * first, for the page indexing below to work. 2095 */ 2096 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2097 2098 if (!pte || huge_pte_none(huge_ptep_get(pte)) || 2099 (write && !pte_write(huge_ptep_get(pte)))) { 2100 int ret; 2101 2102 spin_unlock(&mm->page_table_lock); 2103 ret = hugetlb_fault(mm, vma, vaddr, write); 2104 spin_lock(&mm->page_table_lock); 2105 if (!(ret & VM_FAULT_ERROR)) 2106 continue; 2107 2108 remainder = 0; 2109 if (!i) 2110 i = -EFAULT; 2111 break; 2112 } 2113 2114 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2115 page = pte_page(huge_ptep_get(pte)); 2116same_page: 2117 if (pages) { 2118 get_page(page); 2119 pages[i] = page + pfn_offset; 2120 } 2121 2122 if (vmas) 2123 vmas[i] = vma; 2124 2125 vaddr += PAGE_SIZE; 2126 ++pfn_offset; 2127 --remainder; 2128 ++i; 2129 if (vaddr < vma->vm_end && remainder && 2130 pfn_offset < pages_per_huge_page(h)) { 2131 /* 2132 * We use pfn_offset to avoid touching the pageframes 2133 * of this compound page. 2134 */ 2135 goto same_page; 2136 } 2137 } 2138 spin_unlock(&mm->page_table_lock); 2139 *length = remainder; 2140 *position = vaddr; 2141 2142 return i; 2143} 2144 2145void hugetlb_change_protection(struct vm_area_struct *vma, 2146 unsigned long address, unsigned long end, pgprot_t newprot) 2147{ 2148 struct mm_struct *mm = vma->vm_mm; 2149 unsigned long start = address; 2150 pte_t *ptep; 2151 pte_t pte; 2152 struct hstate *h = hstate_vma(vma); 2153 2154 BUG_ON(address >= end); 2155 flush_cache_range(vma, address, end); 2156 2157 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2158 spin_lock(&mm->page_table_lock); 2159 for (; address < end; address += huge_page_size(h)) { 2160 ptep = huge_pte_offset(mm, address); 2161 if (!ptep) 2162 continue; 2163 if (huge_pmd_unshare(mm, &address, ptep)) 2164 continue; 2165 if (!huge_pte_none(huge_ptep_get(ptep))) { 2166 pte = huge_ptep_get_and_clear(mm, address, ptep); 2167 pte = pte_mkhuge(pte_modify(pte, newprot)); 2168 set_huge_pte_at(mm, address, ptep, pte); 2169 } 2170 } 2171 spin_unlock(&mm->page_table_lock); 2172 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2173 2174 flush_tlb_range(vma, start, end); 2175} 2176 2177int hugetlb_reserve_pages(struct inode *inode, 2178 long from, long to, 2179 struct vm_area_struct *vma) 2180{ 2181 long ret, chg; 2182 struct hstate *h = hstate_inode(inode); 2183 2184 if (vma && vma->vm_flags & VM_NORESERVE) 2185 return 0; 2186 2187 /* 2188 * Shared mappings base their reservation on the number of pages that 2189 * are already allocated on behalf of the file. Private mappings need 2190 * to reserve the full area even if read-only as mprotect() may be 2191 * called to make the mapping read-write. Assume !vma is a shm mapping 2192 */ 2193 if (!vma || vma->vm_flags & VM_SHARED) 2194 chg = region_chg(&inode->i_mapping->private_list, from, to); 2195 else { 2196 struct resv_map *resv_map = resv_map_alloc(); 2197 if (!resv_map) 2198 return -ENOMEM; 2199 2200 chg = to - from; 2201 2202 set_vma_resv_map(vma, resv_map); 2203 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 2204 } 2205 2206 if (chg < 0) 2207 return chg; 2208 2209 if (hugetlb_get_quota(inode->i_mapping, chg)) 2210 return -ENOSPC; 2211 ret = hugetlb_acct_memory(h, chg); 2212 if (ret < 0) { 2213 hugetlb_put_quota(inode->i_mapping, chg); 2214 return ret; 2215 } 2216 if (!vma || vma->vm_flags & VM_SHARED) 2217 region_add(&inode->i_mapping->private_list, from, to); 2218 return 0; 2219} 2220 2221void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 2222{ 2223 struct hstate *h = hstate_inode(inode); 2224 long chg = region_truncate(&inode->i_mapping->private_list, offset); 2225 2226 spin_lock(&inode->i_lock); 2227 inode->i_blocks -= blocks_per_huge_page(h); 2228 spin_unlock(&inode->i_lock); 2229 2230 hugetlb_put_quota(inode->i_mapping, (chg - freed)); 2231 hugetlb_acct_memory(h, -(chg - freed)); 2232} 2233