hugetlb.c revision ebdd4aea8d736e3b5ce27ab0a26860c9fded341b
1/* 2 * Generic hugetlb support. 3 * (C) William Irwin, April 2004 4 */ 5#include <linux/gfp.h> 6#include <linux/list.h> 7#include <linux/init.h> 8#include <linux/module.h> 9#include <linux/mm.h> 10#include <linux/seq_file.h> 11#include <linux/sysctl.h> 12#include <linux/highmem.h> 13#include <linux/mmu_notifier.h> 14#include <linux/nodemask.h> 15#include <linux/pagemap.h> 16#include <linux/mempolicy.h> 17#include <linux/cpuset.h> 18#include <linux/mutex.h> 19#include <linux/bootmem.h> 20#include <linux/sysfs.h> 21 22#include <asm/page.h> 23#include <asm/pgtable.h> 24#include <asm/io.h> 25 26#include <linux/hugetlb.h> 27#include "internal.h" 28 29const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 30static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 31unsigned long hugepages_treat_as_movable; 32 33static int max_hstate; 34unsigned int default_hstate_idx; 35struct hstate hstates[HUGE_MAX_HSTATE]; 36 37__initdata LIST_HEAD(huge_boot_pages); 38 39/* for command line parsing */ 40static struct hstate * __initdata parsed_hstate; 41static unsigned long __initdata default_hstate_max_huge_pages; 42static unsigned long __initdata default_hstate_size; 43 44#define for_each_hstate(h) \ 45 for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) 46 47/* 48 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages 49 */ 50static DEFINE_SPINLOCK(hugetlb_lock); 51 52/* 53 * Region tracking -- allows tracking of reservations and instantiated pages 54 * across the pages in a mapping. 55 * 56 * The region data structures are protected by a combination of the mmap_sem 57 * and the hugetlb_instantion_mutex. To access or modify a region the caller 58 * must either hold the mmap_sem for write, or the mmap_sem for read and 59 * the hugetlb_instantiation mutex: 60 * 61 * down_write(&mm->mmap_sem); 62 * or 63 * down_read(&mm->mmap_sem); 64 * mutex_lock(&hugetlb_instantiation_mutex); 65 */ 66struct file_region { 67 struct list_head link; 68 long from; 69 long to; 70}; 71 72static long region_add(struct list_head *head, long f, long t) 73{ 74 struct file_region *rg, *nrg, *trg; 75 76 /* Locate the region we are either in or before. */ 77 list_for_each_entry(rg, head, link) 78 if (f <= rg->to) 79 break; 80 81 /* Round our left edge to the current segment if it encloses us. */ 82 if (f > rg->from) 83 f = rg->from; 84 85 /* Check for and consume any regions we now overlap with. */ 86 nrg = rg; 87 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 88 if (&rg->link == head) 89 break; 90 if (rg->from > t) 91 break; 92 93 /* If this area reaches higher then extend our area to 94 * include it completely. If this is not the first area 95 * which we intend to reuse, free it. */ 96 if (rg->to > t) 97 t = rg->to; 98 if (rg != nrg) { 99 list_del(&rg->link); 100 kfree(rg); 101 } 102 } 103 nrg->from = f; 104 nrg->to = t; 105 return 0; 106} 107 108static long region_chg(struct list_head *head, long f, long t) 109{ 110 struct file_region *rg, *nrg; 111 long chg = 0; 112 113 /* Locate the region we are before or in. */ 114 list_for_each_entry(rg, head, link) 115 if (f <= rg->to) 116 break; 117 118 /* If we are below the current region then a new region is required. 119 * Subtle, allocate a new region at the position but make it zero 120 * size such that we can guarantee to record the reservation. */ 121 if (&rg->link == head || t < rg->from) { 122 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 123 if (!nrg) 124 return -ENOMEM; 125 nrg->from = f; 126 nrg->to = f; 127 INIT_LIST_HEAD(&nrg->link); 128 list_add(&nrg->link, rg->link.prev); 129 130 return t - f; 131 } 132 133 /* Round our left edge to the current segment if it encloses us. */ 134 if (f > rg->from) 135 f = rg->from; 136 chg = t - f; 137 138 /* Check for and consume any regions we now overlap with. */ 139 list_for_each_entry(rg, rg->link.prev, link) { 140 if (&rg->link == head) 141 break; 142 if (rg->from > t) 143 return chg; 144 145 /* We overlap with this area, if it extends futher than 146 * us then we must extend ourselves. Account for its 147 * existing reservation. */ 148 if (rg->to > t) { 149 chg += rg->to - t; 150 t = rg->to; 151 } 152 chg -= rg->to - rg->from; 153 } 154 return chg; 155} 156 157static long region_truncate(struct list_head *head, long end) 158{ 159 struct file_region *rg, *trg; 160 long chg = 0; 161 162 /* Locate the region we are either in or before. */ 163 list_for_each_entry(rg, head, link) 164 if (end <= rg->to) 165 break; 166 if (&rg->link == head) 167 return 0; 168 169 /* If we are in the middle of a region then adjust it. */ 170 if (end > rg->from) { 171 chg = rg->to - end; 172 rg->to = end; 173 rg = list_entry(rg->link.next, typeof(*rg), link); 174 } 175 176 /* Drop any remaining regions. */ 177 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 178 if (&rg->link == head) 179 break; 180 chg += rg->to - rg->from; 181 list_del(&rg->link); 182 kfree(rg); 183 } 184 return chg; 185} 186 187static long region_count(struct list_head *head, long f, long t) 188{ 189 struct file_region *rg; 190 long chg = 0; 191 192 /* Locate each segment we overlap with, and count that overlap. */ 193 list_for_each_entry(rg, head, link) { 194 int seg_from; 195 int seg_to; 196 197 if (rg->to <= f) 198 continue; 199 if (rg->from >= t) 200 break; 201 202 seg_from = max(rg->from, f); 203 seg_to = min(rg->to, t); 204 205 chg += seg_to - seg_from; 206 } 207 208 return chg; 209} 210 211/* 212 * Convert the address within this vma to the page offset within 213 * the mapping, in pagecache page units; huge pages here. 214 */ 215static pgoff_t vma_hugecache_offset(struct hstate *h, 216 struct vm_area_struct *vma, unsigned long address) 217{ 218 return ((address - vma->vm_start) >> huge_page_shift(h)) + 219 (vma->vm_pgoff >> huge_page_order(h)); 220} 221 222/* 223 * Return the size of the pages allocated when backing a VMA. In the majority 224 * cases this will be same size as used by the page table entries. 225 */ 226unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) 227{ 228 struct hstate *hstate; 229 230 if (!is_vm_hugetlb_page(vma)) 231 return PAGE_SIZE; 232 233 hstate = hstate_vma(vma); 234 235 return 1UL << (hstate->order + PAGE_SHIFT); 236} 237 238/* 239 * Return the page size being used by the MMU to back a VMA. In the majority 240 * of cases, the page size used by the kernel matches the MMU size. On 241 * architectures where it differs, an architecture-specific version of this 242 * function is required. 243 */ 244#ifndef vma_mmu_pagesize 245unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 246{ 247 return vma_kernel_pagesize(vma); 248} 249#endif 250 251/* 252 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 253 * bits of the reservation map pointer, which are always clear due to 254 * alignment. 255 */ 256#define HPAGE_RESV_OWNER (1UL << 0) 257#define HPAGE_RESV_UNMAPPED (1UL << 1) 258#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 259 260/* 261 * These helpers are used to track how many pages are reserved for 262 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 263 * is guaranteed to have their future faults succeed. 264 * 265 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 266 * the reserve counters are updated with the hugetlb_lock held. It is safe 267 * to reset the VMA at fork() time as it is not in use yet and there is no 268 * chance of the global counters getting corrupted as a result of the values. 269 * 270 * The private mapping reservation is represented in a subtly different 271 * manner to a shared mapping. A shared mapping has a region map associated 272 * with the underlying file, this region map represents the backing file 273 * pages which have ever had a reservation assigned which this persists even 274 * after the page is instantiated. A private mapping has a region map 275 * associated with the original mmap which is attached to all VMAs which 276 * reference it, this region map represents those offsets which have consumed 277 * reservation ie. where pages have been instantiated. 278 */ 279static unsigned long get_vma_private_data(struct vm_area_struct *vma) 280{ 281 return (unsigned long)vma->vm_private_data; 282} 283 284static void set_vma_private_data(struct vm_area_struct *vma, 285 unsigned long value) 286{ 287 vma->vm_private_data = (void *)value; 288} 289 290struct resv_map { 291 struct kref refs; 292 struct list_head regions; 293}; 294 295static struct resv_map *resv_map_alloc(void) 296{ 297 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 298 if (!resv_map) 299 return NULL; 300 301 kref_init(&resv_map->refs); 302 INIT_LIST_HEAD(&resv_map->regions); 303 304 return resv_map; 305} 306 307static void resv_map_release(struct kref *ref) 308{ 309 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 310 311 /* Clear out any active regions before we release the map. */ 312 region_truncate(&resv_map->regions, 0); 313 kfree(resv_map); 314} 315 316static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 317{ 318 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 319 if (!(vma->vm_flags & VM_SHARED)) 320 return (struct resv_map *)(get_vma_private_data(vma) & 321 ~HPAGE_RESV_MASK); 322 return NULL; 323} 324 325static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 326{ 327 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 328 VM_BUG_ON(vma->vm_flags & VM_SHARED); 329 330 set_vma_private_data(vma, (get_vma_private_data(vma) & 331 HPAGE_RESV_MASK) | (unsigned long)map); 332} 333 334static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 335{ 336 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 337 VM_BUG_ON(vma->vm_flags & VM_SHARED); 338 339 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 340} 341 342static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 343{ 344 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 345 346 return (get_vma_private_data(vma) & flag) != 0; 347} 348 349/* Decrement the reserved pages in the hugepage pool by one */ 350static void decrement_hugepage_resv_vma(struct hstate *h, 351 struct vm_area_struct *vma) 352{ 353 if (vma->vm_flags & VM_NORESERVE) 354 return; 355 356 if (vma->vm_flags & VM_SHARED) { 357 /* Shared mappings always use reserves */ 358 h->resv_huge_pages--; 359 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 360 /* 361 * Only the process that called mmap() has reserves for 362 * private mappings. 363 */ 364 h->resv_huge_pages--; 365 } 366} 367 368/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 369void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 370{ 371 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 372 if (!(vma->vm_flags & VM_SHARED)) 373 vma->vm_private_data = (void *)0; 374} 375 376/* Returns true if the VMA has associated reserve pages */ 377static int vma_has_reserves(struct vm_area_struct *vma) 378{ 379 if (vma->vm_flags & VM_SHARED) 380 return 1; 381 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 382 return 1; 383 return 0; 384} 385 386static void clear_gigantic_page(struct page *page, 387 unsigned long addr, unsigned long sz) 388{ 389 int i; 390 struct page *p = page; 391 392 might_sleep(); 393 for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) { 394 cond_resched(); 395 clear_user_highpage(p, addr + i * PAGE_SIZE); 396 } 397} 398static void clear_huge_page(struct page *page, 399 unsigned long addr, unsigned long sz) 400{ 401 int i; 402 403 if (unlikely(sz > MAX_ORDER_NR_PAGES)) { 404 clear_gigantic_page(page, addr, sz); 405 return; 406 } 407 408 might_sleep(); 409 for (i = 0; i < sz/PAGE_SIZE; i++) { 410 cond_resched(); 411 clear_user_highpage(page + i, addr + i * PAGE_SIZE); 412 } 413} 414 415static void copy_gigantic_page(struct page *dst, struct page *src, 416 unsigned long addr, struct vm_area_struct *vma) 417{ 418 int i; 419 struct hstate *h = hstate_vma(vma); 420 struct page *dst_base = dst; 421 struct page *src_base = src; 422 might_sleep(); 423 for (i = 0; i < pages_per_huge_page(h); ) { 424 cond_resched(); 425 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); 426 427 i++; 428 dst = mem_map_next(dst, dst_base, i); 429 src = mem_map_next(src, src_base, i); 430 } 431} 432static void copy_huge_page(struct page *dst, struct page *src, 433 unsigned long addr, struct vm_area_struct *vma) 434{ 435 int i; 436 struct hstate *h = hstate_vma(vma); 437 438 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 439 copy_gigantic_page(dst, src, addr, vma); 440 return; 441 } 442 443 might_sleep(); 444 for (i = 0; i < pages_per_huge_page(h); i++) { 445 cond_resched(); 446 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); 447 } 448} 449 450static void enqueue_huge_page(struct hstate *h, struct page *page) 451{ 452 int nid = page_to_nid(page); 453 list_add(&page->lru, &h->hugepage_freelists[nid]); 454 h->free_huge_pages++; 455 h->free_huge_pages_node[nid]++; 456} 457 458static struct page *dequeue_huge_page(struct hstate *h) 459{ 460 int nid; 461 struct page *page = NULL; 462 463 for (nid = 0; nid < MAX_NUMNODES; ++nid) { 464 if (!list_empty(&h->hugepage_freelists[nid])) { 465 page = list_entry(h->hugepage_freelists[nid].next, 466 struct page, lru); 467 list_del(&page->lru); 468 h->free_huge_pages--; 469 h->free_huge_pages_node[nid]--; 470 break; 471 } 472 } 473 return page; 474} 475 476static struct page *dequeue_huge_page_vma(struct hstate *h, 477 struct vm_area_struct *vma, 478 unsigned long address, int avoid_reserve) 479{ 480 int nid; 481 struct page *page = NULL; 482 struct mempolicy *mpol; 483 nodemask_t *nodemask; 484 struct zonelist *zonelist = huge_zonelist(vma, address, 485 htlb_alloc_mask, &mpol, &nodemask); 486 struct zone *zone; 487 struct zoneref *z; 488 489 /* 490 * A child process with MAP_PRIVATE mappings created by their parent 491 * have no page reserves. This check ensures that reservations are 492 * not "stolen". The child may still get SIGKILLed 493 */ 494 if (!vma_has_reserves(vma) && 495 h->free_huge_pages - h->resv_huge_pages == 0) 496 return NULL; 497 498 /* If reserves cannot be used, ensure enough pages are in the pool */ 499 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 500 return NULL; 501 502 for_each_zone_zonelist_nodemask(zone, z, zonelist, 503 MAX_NR_ZONES - 1, nodemask) { 504 nid = zone_to_nid(zone); 505 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && 506 !list_empty(&h->hugepage_freelists[nid])) { 507 page = list_entry(h->hugepage_freelists[nid].next, 508 struct page, lru); 509 list_del(&page->lru); 510 h->free_huge_pages--; 511 h->free_huge_pages_node[nid]--; 512 513 if (!avoid_reserve) 514 decrement_hugepage_resv_vma(h, vma); 515 516 break; 517 } 518 } 519 mpol_cond_put(mpol); 520 return page; 521} 522 523static void update_and_free_page(struct hstate *h, struct page *page) 524{ 525 int i; 526 527 VM_BUG_ON(h->order >= MAX_ORDER); 528 529 h->nr_huge_pages--; 530 h->nr_huge_pages_node[page_to_nid(page)]--; 531 for (i = 0; i < pages_per_huge_page(h); i++) { 532 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 533 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 534 1 << PG_private | 1<< PG_writeback); 535 } 536 set_compound_page_dtor(page, NULL); 537 set_page_refcounted(page); 538 arch_release_hugepage(page); 539 __free_pages(page, huge_page_order(h)); 540} 541 542struct hstate *size_to_hstate(unsigned long size) 543{ 544 struct hstate *h; 545 546 for_each_hstate(h) { 547 if (huge_page_size(h) == size) 548 return h; 549 } 550 return NULL; 551} 552 553static void free_huge_page(struct page *page) 554{ 555 /* 556 * Can't pass hstate in here because it is called from the 557 * compound page destructor. 558 */ 559 struct hstate *h = page_hstate(page); 560 int nid = page_to_nid(page); 561 struct address_space *mapping; 562 563 mapping = (struct address_space *) page_private(page); 564 set_page_private(page, 0); 565 BUG_ON(page_count(page)); 566 INIT_LIST_HEAD(&page->lru); 567 568 spin_lock(&hugetlb_lock); 569 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 570 update_and_free_page(h, page); 571 h->surplus_huge_pages--; 572 h->surplus_huge_pages_node[nid]--; 573 } else { 574 enqueue_huge_page(h, page); 575 } 576 spin_unlock(&hugetlb_lock); 577 if (mapping) 578 hugetlb_put_quota(mapping, 1); 579} 580 581/* 582 * Increment or decrement surplus_huge_pages. Keep node-specific counters 583 * balanced by operating on them in a round-robin fashion. 584 * Returns 1 if an adjustment was made. 585 */ 586static int adjust_pool_surplus(struct hstate *h, int delta) 587{ 588 static int prev_nid; 589 int nid = prev_nid; 590 int ret = 0; 591 592 VM_BUG_ON(delta != -1 && delta != 1); 593 do { 594 nid = next_node(nid, node_online_map); 595 if (nid == MAX_NUMNODES) 596 nid = first_node(node_online_map); 597 598 /* To shrink on this node, there must be a surplus page */ 599 if (delta < 0 && !h->surplus_huge_pages_node[nid]) 600 continue; 601 /* Surplus cannot exceed the total number of pages */ 602 if (delta > 0 && h->surplus_huge_pages_node[nid] >= 603 h->nr_huge_pages_node[nid]) 604 continue; 605 606 h->surplus_huge_pages += delta; 607 h->surplus_huge_pages_node[nid] += delta; 608 ret = 1; 609 break; 610 } while (nid != prev_nid); 611 612 prev_nid = nid; 613 return ret; 614} 615 616static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 617{ 618 set_compound_page_dtor(page, free_huge_page); 619 spin_lock(&hugetlb_lock); 620 h->nr_huge_pages++; 621 h->nr_huge_pages_node[nid]++; 622 spin_unlock(&hugetlb_lock); 623 put_page(page); /* free it into the hugepage allocator */ 624} 625 626static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 627{ 628 struct page *page; 629 630 if (h->order >= MAX_ORDER) 631 return NULL; 632 633 page = alloc_pages_node(nid, 634 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 635 __GFP_REPEAT|__GFP_NOWARN, 636 huge_page_order(h)); 637 if (page) { 638 if (arch_prepare_hugepage(page)) { 639 __free_pages(page, huge_page_order(h)); 640 return NULL; 641 } 642 prep_new_huge_page(h, page, nid); 643 } 644 645 return page; 646} 647 648/* 649 * Use a helper variable to find the next node and then 650 * copy it back to hugetlb_next_nid afterwards: 651 * otherwise there's a window in which a racer might 652 * pass invalid nid MAX_NUMNODES to alloc_pages_node. 653 * But we don't need to use a spin_lock here: it really 654 * doesn't matter if occasionally a racer chooses the 655 * same nid as we do. Move nid forward in the mask even 656 * if we just successfully allocated a hugepage so that 657 * the next caller gets hugepages on the next node. 658 */ 659static int hstate_next_node(struct hstate *h) 660{ 661 int next_nid; 662 next_nid = next_node(h->hugetlb_next_nid, node_online_map); 663 if (next_nid == MAX_NUMNODES) 664 next_nid = first_node(node_online_map); 665 h->hugetlb_next_nid = next_nid; 666 return next_nid; 667} 668 669static int alloc_fresh_huge_page(struct hstate *h) 670{ 671 struct page *page; 672 int start_nid; 673 int next_nid; 674 int ret = 0; 675 676 start_nid = h->hugetlb_next_nid; 677 678 do { 679 page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid); 680 if (page) 681 ret = 1; 682 next_nid = hstate_next_node(h); 683 } while (!page && h->hugetlb_next_nid != start_nid); 684 685 if (ret) 686 count_vm_event(HTLB_BUDDY_PGALLOC); 687 else 688 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 689 690 return ret; 691} 692 693static struct page *alloc_buddy_huge_page(struct hstate *h, 694 struct vm_area_struct *vma, unsigned long address) 695{ 696 struct page *page; 697 unsigned int nid; 698 699 if (h->order >= MAX_ORDER) 700 return NULL; 701 702 /* 703 * Assume we will successfully allocate the surplus page to 704 * prevent racing processes from causing the surplus to exceed 705 * overcommit 706 * 707 * This however introduces a different race, where a process B 708 * tries to grow the static hugepage pool while alloc_pages() is 709 * called by process A. B will only examine the per-node 710 * counters in determining if surplus huge pages can be 711 * converted to normal huge pages in adjust_pool_surplus(). A 712 * won't be able to increment the per-node counter, until the 713 * lock is dropped by B, but B doesn't drop hugetlb_lock until 714 * no more huge pages can be converted from surplus to normal 715 * state (and doesn't try to convert again). Thus, we have a 716 * case where a surplus huge page exists, the pool is grown, and 717 * the surplus huge page still exists after, even though it 718 * should just have been converted to a normal huge page. This 719 * does not leak memory, though, as the hugepage will be freed 720 * once it is out of use. It also does not allow the counters to 721 * go out of whack in adjust_pool_surplus() as we don't modify 722 * the node values until we've gotten the hugepage and only the 723 * per-node value is checked there. 724 */ 725 spin_lock(&hugetlb_lock); 726 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 727 spin_unlock(&hugetlb_lock); 728 return NULL; 729 } else { 730 h->nr_huge_pages++; 731 h->surplus_huge_pages++; 732 } 733 spin_unlock(&hugetlb_lock); 734 735 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 736 __GFP_REPEAT|__GFP_NOWARN, 737 huge_page_order(h)); 738 739 if (page && arch_prepare_hugepage(page)) { 740 __free_pages(page, huge_page_order(h)); 741 return NULL; 742 } 743 744 spin_lock(&hugetlb_lock); 745 if (page) { 746 /* 747 * This page is now managed by the hugetlb allocator and has 748 * no users -- drop the buddy allocator's reference. 749 */ 750 put_page_testzero(page); 751 VM_BUG_ON(page_count(page)); 752 nid = page_to_nid(page); 753 set_compound_page_dtor(page, free_huge_page); 754 /* 755 * We incremented the global counters already 756 */ 757 h->nr_huge_pages_node[nid]++; 758 h->surplus_huge_pages_node[nid]++; 759 __count_vm_event(HTLB_BUDDY_PGALLOC); 760 } else { 761 h->nr_huge_pages--; 762 h->surplus_huge_pages--; 763 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 764 } 765 spin_unlock(&hugetlb_lock); 766 767 return page; 768} 769 770/* 771 * Increase the hugetlb pool such that it can accomodate a reservation 772 * of size 'delta'. 773 */ 774static int gather_surplus_pages(struct hstate *h, int delta) 775{ 776 struct list_head surplus_list; 777 struct page *page, *tmp; 778 int ret, i; 779 int needed, allocated; 780 781 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 782 if (needed <= 0) { 783 h->resv_huge_pages += delta; 784 return 0; 785 } 786 787 allocated = 0; 788 INIT_LIST_HEAD(&surplus_list); 789 790 ret = -ENOMEM; 791retry: 792 spin_unlock(&hugetlb_lock); 793 for (i = 0; i < needed; i++) { 794 page = alloc_buddy_huge_page(h, NULL, 0); 795 if (!page) { 796 /* 797 * We were not able to allocate enough pages to 798 * satisfy the entire reservation so we free what 799 * we've allocated so far. 800 */ 801 spin_lock(&hugetlb_lock); 802 needed = 0; 803 goto free; 804 } 805 806 list_add(&page->lru, &surplus_list); 807 } 808 allocated += needed; 809 810 /* 811 * After retaking hugetlb_lock, we need to recalculate 'needed' 812 * because either resv_huge_pages or free_huge_pages may have changed. 813 */ 814 spin_lock(&hugetlb_lock); 815 needed = (h->resv_huge_pages + delta) - 816 (h->free_huge_pages + allocated); 817 if (needed > 0) 818 goto retry; 819 820 /* 821 * The surplus_list now contains _at_least_ the number of extra pages 822 * needed to accomodate the reservation. Add the appropriate number 823 * of pages to the hugetlb pool and free the extras back to the buddy 824 * allocator. Commit the entire reservation here to prevent another 825 * process from stealing the pages as they are added to the pool but 826 * before they are reserved. 827 */ 828 needed += allocated; 829 h->resv_huge_pages += delta; 830 ret = 0; 831free: 832 /* Free the needed pages to the hugetlb pool */ 833 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 834 if ((--needed) < 0) 835 break; 836 list_del(&page->lru); 837 enqueue_huge_page(h, page); 838 } 839 840 /* Free unnecessary surplus pages to the buddy allocator */ 841 if (!list_empty(&surplus_list)) { 842 spin_unlock(&hugetlb_lock); 843 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 844 list_del(&page->lru); 845 /* 846 * The page has a reference count of zero already, so 847 * call free_huge_page directly instead of using 848 * put_page. This must be done with hugetlb_lock 849 * unlocked which is safe because free_huge_page takes 850 * hugetlb_lock before deciding how to free the page. 851 */ 852 free_huge_page(page); 853 } 854 spin_lock(&hugetlb_lock); 855 } 856 857 return ret; 858} 859 860/* 861 * When releasing a hugetlb pool reservation, any surplus pages that were 862 * allocated to satisfy the reservation must be explicitly freed if they were 863 * never used. 864 */ 865static void return_unused_surplus_pages(struct hstate *h, 866 unsigned long unused_resv_pages) 867{ 868 static int nid = -1; 869 struct page *page; 870 unsigned long nr_pages; 871 872 /* 873 * We want to release as many surplus pages as possible, spread 874 * evenly across all nodes. Iterate across all nodes until we 875 * can no longer free unreserved surplus pages. This occurs when 876 * the nodes with surplus pages have no free pages. 877 */ 878 unsigned long remaining_iterations = num_online_nodes(); 879 880 /* Uncommit the reservation */ 881 h->resv_huge_pages -= unused_resv_pages; 882 883 /* Cannot return gigantic pages currently */ 884 if (h->order >= MAX_ORDER) 885 return; 886 887 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 888 889 while (remaining_iterations-- && nr_pages) { 890 nid = next_node(nid, node_online_map); 891 if (nid == MAX_NUMNODES) 892 nid = first_node(node_online_map); 893 894 if (!h->surplus_huge_pages_node[nid]) 895 continue; 896 897 if (!list_empty(&h->hugepage_freelists[nid])) { 898 page = list_entry(h->hugepage_freelists[nid].next, 899 struct page, lru); 900 list_del(&page->lru); 901 update_and_free_page(h, page); 902 h->free_huge_pages--; 903 h->free_huge_pages_node[nid]--; 904 h->surplus_huge_pages--; 905 h->surplus_huge_pages_node[nid]--; 906 nr_pages--; 907 remaining_iterations = num_online_nodes(); 908 } 909 } 910} 911 912/* 913 * Determine if the huge page at addr within the vma has an associated 914 * reservation. Where it does not we will need to logically increase 915 * reservation and actually increase quota before an allocation can occur. 916 * Where any new reservation would be required the reservation change is 917 * prepared, but not committed. Once the page has been quota'd allocated 918 * an instantiated the change should be committed via vma_commit_reservation. 919 * No action is required on failure. 920 */ 921static int vma_needs_reservation(struct hstate *h, 922 struct vm_area_struct *vma, unsigned long addr) 923{ 924 struct address_space *mapping = vma->vm_file->f_mapping; 925 struct inode *inode = mapping->host; 926 927 if (vma->vm_flags & VM_SHARED) { 928 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 929 return region_chg(&inode->i_mapping->private_list, 930 idx, idx + 1); 931 932 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 933 return 1; 934 935 } else { 936 int err; 937 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 938 struct resv_map *reservations = vma_resv_map(vma); 939 940 err = region_chg(&reservations->regions, idx, idx + 1); 941 if (err < 0) 942 return err; 943 return 0; 944 } 945} 946static void vma_commit_reservation(struct hstate *h, 947 struct vm_area_struct *vma, unsigned long addr) 948{ 949 struct address_space *mapping = vma->vm_file->f_mapping; 950 struct inode *inode = mapping->host; 951 952 if (vma->vm_flags & VM_SHARED) { 953 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 954 region_add(&inode->i_mapping->private_list, idx, idx + 1); 955 956 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 957 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 958 struct resv_map *reservations = vma_resv_map(vma); 959 960 /* Mark this page used in the map. */ 961 region_add(&reservations->regions, idx, idx + 1); 962 } 963} 964 965static struct page *alloc_huge_page(struct vm_area_struct *vma, 966 unsigned long addr, int avoid_reserve) 967{ 968 struct hstate *h = hstate_vma(vma); 969 struct page *page; 970 struct address_space *mapping = vma->vm_file->f_mapping; 971 struct inode *inode = mapping->host; 972 unsigned int chg; 973 974 /* 975 * Processes that did not create the mapping will have no reserves and 976 * will not have accounted against quota. Check that the quota can be 977 * made before satisfying the allocation 978 * MAP_NORESERVE mappings may also need pages and quota allocated 979 * if no reserve mapping overlaps. 980 */ 981 chg = vma_needs_reservation(h, vma, addr); 982 if (chg < 0) 983 return ERR_PTR(chg); 984 if (chg) 985 if (hugetlb_get_quota(inode->i_mapping, chg)) 986 return ERR_PTR(-ENOSPC); 987 988 spin_lock(&hugetlb_lock); 989 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 990 spin_unlock(&hugetlb_lock); 991 992 if (!page) { 993 page = alloc_buddy_huge_page(h, vma, addr); 994 if (!page) { 995 hugetlb_put_quota(inode->i_mapping, chg); 996 return ERR_PTR(-VM_FAULT_OOM); 997 } 998 } 999 1000 set_page_refcounted(page); 1001 set_page_private(page, (unsigned long) mapping); 1002 1003 vma_commit_reservation(h, vma, addr); 1004 1005 return page; 1006} 1007 1008__attribute__((weak)) int alloc_bootmem_huge_page(struct hstate *h) 1009{ 1010 struct huge_bootmem_page *m; 1011 int nr_nodes = nodes_weight(node_online_map); 1012 1013 while (nr_nodes) { 1014 void *addr; 1015 1016 addr = __alloc_bootmem_node_nopanic( 1017 NODE_DATA(h->hugetlb_next_nid), 1018 huge_page_size(h), huge_page_size(h), 0); 1019 1020 if (addr) { 1021 /* 1022 * Use the beginning of the huge page to store the 1023 * huge_bootmem_page struct (until gather_bootmem 1024 * puts them into the mem_map). 1025 */ 1026 m = addr; 1027 if (m) 1028 goto found; 1029 } 1030 hstate_next_node(h); 1031 nr_nodes--; 1032 } 1033 return 0; 1034 1035found: 1036 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1037 /* Put them into a private list first because mem_map is not up yet */ 1038 list_add(&m->list, &huge_boot_pages); 1039 m->hstate = h; 1040 return 1; 1041} 1042 1043static void prep_compound_huge_page(struct page *page, int order) 1044{ 1045 if (unlikely(order > (MAX_ORDER - 1))) 1046 prep_compound_gigantic_page(page, order); 1047 else 1048 prep_compound_page(page, order); 1049} 1050 1051/* Put bootmem huge pages into the standard lists after mem_map is up */ 1052static void __init gather_bootmem_prealloc(void) 1053{ 1054 struct huge_bootmem_page *m; 1055 1056 list_for_each_entry(m, &huge_boot_pages, list) { 1057 struct page *page = virt_to_page(m); 1058 struct hstate *h = m->hstate; 1059 __ClearPageReserved(page); 1060 WARN_ON(page_count(page) != 1); 1061 prep_compound_huge_page(page, h->order); 1062 prep_new_huge_page(h, page, page_to_nid(page)); 1063 } 1064} 1065 1066static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1067{ 1068 unsigned long i; 1069 1070 for (i = 0; i < h->max_huge_pages; ++i) { 1071 if (h->order >= MAX_ORDER) { 1072 if (!alloc_bootmem_huge_page(h)) 1073 break; 1074 } else if (!alloc_fresh_huge_page(h)) 1075 break; 1076 } 1077 h->max_huge_pages = i; 1078} 1079 1080static void __init hugetlb_init_hstates(void) 1081{ 1082 struct hstate *h; 1083 1084 for_each_hstate(h) { 1085 /* oversize hugepages were init'ed in early boot */ 1086 if (h->order < MAX_ORDER) 1087 hugetlb_hstate_alloc_pages(h); 1088 } 1089} 1090 1091static char * __init memfmt(char *buf, unsigned long n) 1092{ 1093 if (n >= (1UL << 30)) 1094 sprintf(buf, "%lu GB", n >> 30); 1095 else if (n >= (1UL << 20)) 1096 sprintf(buf, "%lu MB", n >> 20); 1097 else 1098 sprintf(buf, "%lu KB", n >> 10); 1099 return buf; 1100} 1101 1102static void __init report_hugepages(void) 1103{ 1104 struct hstate *h; 1105 1106 for_each_hstate(h) { 1107 char buf[32]; 1108 printk(KERN_INFO "HugeTLB registered %s page size, " 1109 "pre-allocated %ld pages\n", 1110 memfmt(buf, huge_page_size(h)), 1111 h->free_huge_pages); 1112 } 1113} 1114 1115#ifdef CONFIG_HIGHMEM 1116static void try_to_free_low(struct hstate *h, unsigned long count) 1117{ 1118 int i; 1119 1120 if (h->order >= MAX_ORDER) 1121 return; 1122 1123 for (i = 0; i < MAX_NUMNODES; ++i) { 1124 struct page *page, *next; 1125 struct list_head *freel = &h->hugepage_freelists[i]; 1126 list_for_each_entry_safe(page, next, freel, lru) { 1127 if (count >= h->nr_huge_pages) 1128 return; 1129 if (PageHighMem(page)) 1130 continue; 1131 list_del(&page->lru); 1132 update_and_free_page(h, page); 1133 h->free_huge_pages--; 1134 h->free_huge_pages_node[page_to_nid(page)]--; 1135 } 1136 } 1137} 1138#else 1139static inline void try_to_free_low(struct hstate *h, unsigned long count) 1140{ 1141} 1142#endif 1143 1144#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1145static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count) 1146{ 1147 unsigned long min_count, ret; 1148 1149 if (h->order >= MAX_ORDER) 1150 return h->max_huge_pages; 1151 1152 /* 1153 * Increase the pool size 1154 * First take pages out of surplus state. Then make up the 1155 * remaining difference by allocating fresh huge pages. 1156 * 1157 * We might race with alloc_buddy_huge_page() here and be unable 1158 * to convert a surplus huge page to a normal huge page. That is 1159 * not critical, though, it just means the overall size of the 1160 * pool might be one hugepage larger than it needs to be, but 1161 * within all the constraints specified by the sysctls. 1162 */ 1163 spin_lock(&hugetlb_lock); 1164 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1165 if (!adjust_pool_surplus(h, -1)) 1166 break; 1167 } 1168 1169 while (count > persistent_huge_pages(h)) { 1170 /* 1171 * If this allocation races such that we no longer need the 1172 * page, free_huge_page will handle it by freeing the page 1173 * and reducing the surplus. 1174 */ 1175 spin_unlock(&hugetlb_lock); 1176 ret = alloc_fresh_huge_page(h); 1177 spin_lock(&hugetlb_lock); 1178 if (!ret) 1179 goto out; 1180 1181 } 1182 1183 /* 1184 * Decrease the pool size 1185 * First return free pages to the buddy allocator (being careful 1186 * to keep enough around to satisfy reservations). Then place 1187 * pages into surplus state as needed so the pool will shrink 1188 * to the desired size as pages become free. 1189 * 1190 * By placing pages into the surplus state independent of the 1191 * overcommit value, we are allowing the surplus pool size to 1192 * exceed overcommit. There are few sane options here. Since 1193 * alloc_buddy_huge_page() is checking the global counter, 1194 * though, we'll note that we're not allowed to exceed surplus 1195 * and won't grow the pool anywhere else. Not until one of the 1196 * sysctls are changed, or the surplus pages go out of use. 1197 */ 1198 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1199 min_count = max(count, min_count); 1200 try_to_free_low(h, min_count); 1201 while (min_count < persistent_huge_pages(h)) { 1202 struct page *page = dequeue_huge_page(h); 1203 if (!page) 1204 break; 1205 update_and_free_page(h, page); 1206 } 1207 while (count < persistent_huge_pages(h)) { 1208 if (!adjust_pool_surplus(h, 1)) 1209 break; 1210 } 1211out: 1212 ret = persistent_huge_pages(h); 1213 spin_unlock(&hugetlb_lock); 1214 return ret; 1215} 1216 1217#define HSTATE_ATTR_RO(_name) \ 1218 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1219 1220#define HSTATE_ATTR(_name) \ 1221 static struct kobj_attribute _name##_attr = \ 1222 __ATTR(_name, 0644, _name##_show, _name##_store) 1223 1224static struct kobject *hugepages_kobj; 1225static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1226 1227static struct hstate *kobj_to_hstate(struct kobject *kobj) 1228{ 1229 int i; 1230 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1231 if (hstate_kobjs[i] == kobj) 1232 return &hstates[i]; 1233 BUG(); 1234 return NULL; 1235} 1236 1237static ssize_t nr_hugepages_show(struct kobject *kobj, 1238 struct kobj_attribute *attr, char *buf) 1239{ 1240 struct hstate *h = kobj_to_hstate(kobj); 1241 return sprintf(buf, "%lu\n", h->nr_huge_pages); 1242} 1243static ssize_t nr_hugepages_store(struct kobject *kobj, 1244 struct kobj_attribute *attr, const char *buf, size_t count) 1245{ 1246 int err; 1247 unsigned long input; 1248 struct hstate *h = kobj_to_hstate(kobj); 1249 1250 err = strict_strtoul(buf, 10, &input); 1251 if (err) 1252 return 0; 1253 1254 h->max_huge_pages = set_max_huge_pages(h, input); 1255 1256 return count; 1257} 1258HSTATE_ATTR(nr_hugepages); 1259 1260static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1261 struct kobj_attribute *attr, char *buf) 1262{ 1263 struct hstate *h = kobj_to_hstate(kobj); 1264 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1265} 1266static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1267 struct kobj_attribute *attr, const char *buf, size_t count) 1268{ 1269 int err; 1270 unsigned long input; 1271 struct hstate *h = kobj_to_hstate(kobj); 1272 1273 err = strict_strtoul(buf, 10, &input); 1274 if (err) 1275 return 0; 1276 1277 spin_lock(&hugetlb_lock); 1278 h->nr_overcommit_huge_pages = input; 1279 spin_unlock(&hugetlb_lock); 1280 1281 return count; 1282} 1283HSTATE_ATTR(nr_overcommit_hugepages); 1284 1285static ssize_t free_hugepages_show(struct kobject *kobj, 1286 struct kobj_attribute *attr, char *buf) 1287{ 1288 struct hstate *h = kobj_to_hstate(kobj); 1289 return sprintf(buf, "%lu\n", h->free_huge_pages); 1290} 1291HSTATE_ATTR_RO(free_hugepages); 1292 1293static ssize_t resv_hugepages_show(struct kobject *kobj, 1294 struct kobj_attribute *attr, char *buf) 1295{ 1296 struct hstate *h = kobj_to_hstate(kobj); 1297 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1298} 1299HSTATE_ATTR_RO(resv_hugepages); 1300 1301static ssize_t surplus_hugepages_show(struct kobject *kobj, 1302 struct kobj_attribute *attr, char *buf) 1303{ 1304 struct hstate *h = kobj_to_hstate(kobj); 1305 return sprintf(buf, "%lu\n", h->surplus_huge_pages); 1306} 1307HSTATE_ATTR_RO(surplus_hugepages); 1308 1309static struct attribute *hstate_attrs[] = { 1310 &nr_hugepages_attr.attr, 1311 &nr_overcommit_hugepages_attr.attr, 1312 &free_hugepages_attr.attr, 1313 &resv_hugepages_attr.attr, 1314 &surplus_hugepages_attr.attr, 1315 NULL, 1316}; 1317 1318static struct attribute_group hstate_attr_group = { 1319 .attrs = hstate_attrs, 1320}; 1321 1322static int __init hugetlb_sysfs_add_hstate(struct hstate *h) 1323{ 1324 int retval; 1325 1326 hstate_kobjs[h - hstates] = kobject_create_and_add(h->name, 1327 hugepages_kobj); 1328 if (!hstate_kobjs[h - hstates]) 1329 return -ENOMEM; 1330 1331 retval = sysfs_create_group(hstate_kobjs[h - hstates], 1332 &hstate_attr_group); 1333 if (retval) 1334 kobject_put(hstate_kobjs[h - hstates]); 1335 1336 return retval; 1337} 1338 1339static void __init hugetlb_sysfs_init(void) 1340{ 1341 struct hstate *h; 1342 int err; 1343 1344 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1345 if (!hugepages_kobj) 1346 return; 1347 1348 for_each_hstate(h) { 1349 err = hugetlb_sysfs_add_hstate(h); 1350 if (err) 1351 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1352 h->name); 1353 } 1354} 1355 1356static void __exit hugetlb_exit(void) 1357{ 1358 struct hstate *h; 1359 1360 for_each_hstate(h) { 1361 kobject_put(hstate_kobjs[h - hstates]); 1362 } 1363 1364 kobject_put(hugepages_kobj); 1365} 1366module_exit(hugetlb_exit); 1367 1368static int __init hugetlb_init(void) 1369{ 1370 /* Some platform decide whether they support huge pages at boot 1371 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1372 * there is no such support 1373 */ 1374 if (HPAGE_SHIFT == 0) 1375 return 0; 1376 1377 if (!size_to_hstate(default_hstate_size)) { 1378 default_hstate_size = HPAGE_SIZE; 1379 if (!size_to_hstate(default_hstate_size)) 1380 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1381 } 1382 default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; 1383 if (default_hstate_max_huge_pages) 1384 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1385 1386 hugetlb_init_hstates(); 1387 1388 gather_bootmem_prealloc(); 1389 1390 report_hugepages(); 1391 1392 hugetlb_sysfs_init(); 1393 1394 return 0; 1395} 1396module_init(hugetlb_init); 1397 1398/* Should be called on processing a hugepagesz=... option */ 1399void __init hugetlb_add_hstate(unsigned order) 1400{ 1401 struct hstate *h; 1402 unsigned long i; 1403 1404 if (size_to_hstate(PAGE_SIZE << order)) { 1405 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1406 return; 1407 } 1408 BUG_ON(max_hstate >= HUGE_MAX_HSTATE); 1409 BUG_ON(order == 0); 1410 h = &hstates[max_hstate++]; 1411 h->order = order; 1412 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1413 h->nr_huge_pages = 0; 1414 h->free_huge_pages = 0; 1415 for (i = 0; i < MAX_NUMNODES; ++i) 1416 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1417 h->hugetlb_next_nid = first_node(node_online_map); 1418 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1419 huge_page_size(h)/1024); 1420 1421 parsed_hstate = h; 1422} 1423 1424static int __init hugetlb_nrpages_setup(char *s) 1425{ 1426 unsigned long *mhp; 1427 static unsigned long *last_mhp; 1428 1429 /* 1430 * !max_hstate means we haven't parsed a hugepagesz= parameter yet, 1431 * so this hugepages= parameter goes to the "default hstate". 1432 */ 1433 if (!max_hstate) 1434 mhp = &default_hstate_max_huge_pages; 1435 else 1436 mhp = &parsed_hstate->max_huge_pages; 1437 1438 if (mhp == last_mhp) { 1439 printk(KERN_WARNING "hugepages= specified twice without " 1440 "interleaving hugepagesz=, ignoring\n"); 1441 return 1; 1442 } 1443 1444 if (sscanf(s, "%lu", mhp) <= 0) 1445 *mhp = 0; 1446 1447 /* 1448 * Global state is always initialized later in hugetlb_init. 1449 * But we need to allocate >= MAX_ORDER hstates here early to still 1450 * use the bootmem allocator. 1451 */ 1452 if (max_hstate && parsed_hstate->order >= MAX_ORDER) 1453 hugetlb_hstate_alloc_pages(parsed_hstate); 1454 1455 last_mhp = mhp; 1456 1457 return 1; 1458} 1459__setup("hugepages=", hugetlb_nrpages_setup); 1460 1461static int __init hugetlb_default_setup(char *s) 1462{ 1463 default_hstate_size = memparse(s, &s); 1464 return 1; 1465} 1466__setup("default_hugepagesz=", hugetlb_default_setup); 1467 1468static unsigned int cpuset_mems_nr(unsigned int *array) 1469{ 1470 int node; 1471 unsigned int nr = 0; 1472 1473 for_each_node_mask(node, cpuset_current_mems_allowed) 1474 nr += array[node]; 1475 1476 return nr; 1477} 1478 1479#ifdef CONFIG_SYSCTL 1480int hugetlb_sysctl_handler(struct ctl_table *table, int write, 1481 struct file *file, void __user *buffer, 1482 size_t *length, loff_t *ppos) 1483{ 1484 struct hstate *h = &default_hstate; 1485 unsigned long tmp; 1486 1487 if (!write) 1488 tmp = h->max_huge_pages; 1489 1490 table->data = &tmp; 1491 table->maxlen = sizeof(unsigned long); 1492 proc_doulongvec_minmax(table, write, file, buffer, length, ppos); 1493 1494 if (write) 1495 h->max_huge_pages = set_max_huge_pages(h, tmp); 1496 1497 return 0; 1498} 1499 1500int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 1501 struct file *file, void __user *buffer, 1502 size_t *length, loff_t *ppos) 1503{ 1504 proc_dointvec(table, write, file, buffer, length, ppos); 1505 if (hugepages_treat_as_movable) 1506 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 1507 else 1508 htlb_alloc_mask = GFP_HIGHUSER; 1509 return 0; 1510} 1511 1512int hugetlb_overcommit_handler(struct ctl_table *table, int write, 1513 struct file *file, void __user *buffer, 1514 size_t *length, loff_t *ppos) 1515{ 1516 struct hstate *h = &default_hstate; 1517 unsigned long tmp; 1518 1519 if (!write) 1520 tmp = h->nr_overcommit_huge_pages; 1521 1522 table->data = &tmp; 1523 table->maxlen = sizeof(unsigned long); 1524 proc_doulongvec_minmax(table, write, file, buffer, length, ppos); 1525 1526 if (write) { 1527 spin_lock(&hugetlb_lock); 1528 h->nr_overcommit_huge_pages = tmp; 1529 spin_unlock(&hugetlb_lock); 1530 } 1531 1532 return 0; 1533} 1534 1535#endif /* CONFIG_SYSCTL */ 1536 1537void hugetlb_report_meminfo(struct seq_file *m) 1538{ 1539 struct hstate *h = &default_hstate; 1540 seq_printf(m, 1541 "HugePages_Total: %5lu\n" 1542 "HugePages_Free: %5lu\n" 1543 "HugePages_Rsvd: %5lu\n" 1544 "HugePages_Surp: %5lu\n" 1545 "Hugepagesize: %8lu kB\n", 1546 h->nr_huge_pages, 1547 h->free_huge_pages, 1548 h->resv_huge_pages, 1549 h->surplus_huge_pages, 1550 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 1551} 1552 1553int hugetlb_report_node_meminfo(int nid, char *buf) 1554{ 1555 struct hstate *h = &default_hstate; 1556 return sprintf(buf, 1557 "Node %d HugePages_Total: %5u\n" 1558 "Node %d HugePages_Free: %5u\n" 1559 "Node %d HugePages_Surp: %5u\n", 1560 nid, h->nr_huge_pages_node[nid], 1561 nid, h->free_huge_pages_node[nid], 1562 nid, h->surplus_huge_pages_node[nid]); 1563} 1564 1565/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 1566unsigned long hugetlb_total_pages(void) 1567{ 1568 struct hstate *h = &default_hstate; 1569 return h->nr_huge_pages * pages_per_huge_page(h); 1570} 1571 1572static int hugetlb_acct_memory(struct hstate *h, long delta) 1573{ 1574 int ret = -ENOMEM; 1575 1576 spin_lock(&hugetlb_lock); 1577 /* 1578 * When cpuset is configured, it breaks the strict hugetlb page 1579 * reservation as the accounting is done on a global variable. Such 1580 * reservation is completely rubbish in the presence of cpuset because 1581 * the reservation is not checked against page availability for the 1582 * current cpuset. Application can still potentially OOM'ed by kernel 1583 * with lack of free htlb page in cpuset that the task is in. 1584 * Attempt to enforce strict accounting with cpuset is almost 1585 * impossible (or too ugly) because cpuset is too fluid that 1586 * task or memory node can be dynamically moved between cpusets. 1587 * 1588 * The change of semantics for shared hugetlb mapping with cpuset is 1589 * undesirable. However, in order to preserve some of the semantics, 1590 * we fall back to check against current free page availability as 1591 * a best attempt and hopefully to minimize the impact of changing 1592 * semantics that cpuset has. 1593 */ 1594 if (delta > 0) { 1595 if (gather_surplus_pages(h, delta) < 0) 1596 goto out; 1597 1598 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 1599 return_unused_surplus_pages(h, delta); 1600 goto out; 1601 } 1602 } 1603 1604 ret = 0; 1605 if (delta < 0) 1606 return_unused_surplus_pages(h, (unsigned long) -delta); 1607 1608out: 1609 spin_unlock(&hugetlb_lock); 1610 return ret; 1611} 1612 1613static void hugetlb_vm_op_open(struct vm_area_struct *vma) 1614{ 1615 struct resv_map *reservations = vma_resv_map(vma); 1616 1617 /* 1618 * This new VMA should share its siblings reservation map if present. 1619 * The VMA will only ever have a valid reservation map pointer where 1620 * it is being copied for another still existing VMA. As that VMA 1621 * has a reference to the reservation map it cannot dissappear until 1622 * after this open call completes. It is therefore safe to take a 1623 * new reference here without additional locking. 1624 */ 1625 if (reservations) 1626 kref_get(&reservations->refs); 1627} 1628 1629static void hugetlb_vm_op_close(struct vm_area_struct *vma) 1630{ 1631 struct hstate *h = hstate_vma(vma); 1632 struct resv_map *reservations = vma_resv_map(vma); 1633 unsigned long reserve; 1634 unsigned long start; 1635 unsigned long end; 1636 1637 if (reservations) { 1638 start = vma_hugecache_offset(h, vma, vma->vm_start); 1639 end = vma_hugecache_offset(h, vma, vma->vm_end); 1640 1641 reserve = (end - start) - 1642 region_count(&reservations->regions, start, end); 1643 1644 kref_put(&reservations->refs, resv_map_release); 1645 1646 if (reserve) { 1647 hugetlb_acct_memory(h, -reserve); 1648 hugetlb_put_quota(vma->vm_file->f_mapping, reserve); 1649 } 1650 } 1651} 1652 1653/* 1654 * We cannot handle pagefaults against hugetlb pages at all. They cause 1655 * handle_mm_fault() to try to instantiate regular-sized pages in the 1656 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 1657 * this far. 1658 */ 1659static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 1660{ 1661 BUG(); 1662 return 0; 1663} 1664 1665struct vm_operations_struct hugetlb_vm_ops = { 1666 .fault = hugetlb_vm_op_fault, 1667 .open = hugetlb_vm_op_open, 1668 .close = hugetlb_vm_op_close, 1669}; 1670 1671static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 1672 int writable) 1673{ 1674 pte_t entry; 1675 1676 if (writable) { 1677 entry = 1678 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 1679 } else { 1680 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 1681 } 1682 entry = pte_mkyoung(entry); 1683 entry = pte_mkhuge(entry); 1684 1685 return entry; 1686} 1687 1688static void set_huge_ptep_writable(struct vm_area_struct *vma, 1689 unsigned long address, pte_t *ptep) 1690{ 1691 pte_t entry; 1692 1693 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 1694 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { 1695 update_mmu_cache(vma, address, entry); 1696 } 1697} 1698 1699 1700int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 1701 struct vm_area_struct *vma) 1702{ 1703 pte_t *src_pte, *dst_pte, entry; 1704 struct page *ptepage; 1705 unsigned long addr; 1706 int cow; 1707 struct hstate *h = hstate_vma(vma); 1708 unsigned long sz = huge_page_size(h); 1709 1710 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 1711 1712 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 1713 src_pte = huge_pte_offset(src, addr); 1714 if (!src_pte) 1715 continue; 1716 dst_pte = huge_pte_alloc(dst, addr, sz); 1717 if (!dst_pte) 1718 goto nomem; 1719 1720 /* If the pagetables are shared don't copy or take references */ 1721 if (dst_pte == src_pte) 1722 continue; 1723 1724 spin_lock(&dst->page_table_lock); 1725 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 1726 if (!huge_pte_none(huge_ptep_get(src_pte))) { 1727 if (cow) 1728 huge_ptep_set_wrprotect(src, addr, src_pte); 1729 entry = huge_ptep_get(src_pte); 1730 ptepage = pte_page(entry); 1731 get_page(ptepage); 1732 set_huge_pte_at(dst, addr, dst_pte, entry); 1733 } 1734 spin_unlock(&src->page_table_lock); 1735 spin_unlock(&dst->page_table_lock); 1736 } 1737 return 0; 1738 1739nomem: 1740 return -ENOMEM; 1741} 1742 1743void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 1744 unsigned long end, struct page *ref_page) 1745{ 1746 struct mm_struct *mm = vma->vm_mm; 1747 unsigned long address; 1748 pte_t *ptep; 1749 pte_t pte; 1750 struct page *page; 1751 struct page *tmp; 1752 struct hstate *h = hstate_vma(vma); 1753 unsigned long sz = huge_page_size(h); 1754 1755 /* 1756 * A page gathering list, protected by per file i_mmap_lock. The 1757 * lock is used to avoid list corruption from multiple unmapping 1758 * of the same page since we are using page->lru. 1759 */ 1760 LIST_HEAD(page_list); 1761 1762 WARN_ON(!is_vm_hugetlb_page(vma)); 1763 BUG_ON(start & ~huge_page_mask(h)); 1764 BUG_ON(end & ~huge_page_mask(h)); 1765 1766 mmu_notifier_invalidate_range_start(mm, start, end); 1767 spin_lock(&mm->page_table_lock); 1768 for (address = start; address < end; address += sz) { 1769 ptep = huge_pte_offset(mm, address); 1770 if (!ptep) 1771 continue; 1772 1773 if (huge_pmd_unshare(mm, &address, ptep)) 1774 continue; 1775 1776 /* 1777 * If a reference page is supplied, it is because a specific 1778 * page is being unmapped, not a range. Ensure the page we 1779 * are about to unmap is the actual page of interest. 1780 */ 1781 if (ref_page) { 1782 pte = huge_ptep_get(ptep); 1783 if (huge_pte_none(pte)) 1784 continue; 1785 page = pte_page(pte); 1786 if (page != ref_page) 1787 continue; 1788 1789 /* 1790 * Mark the VMA as having unmapped its page so that 1791 * future faults in this VMA will fail rather than 1792 * looking like data was lost 1793 */ 1794 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 1795 } 1796 1797 pte = huge_ptep_get_and_clear(mm, address, ptep); 1798 if (huge_pte_none(pte)) 1799 continue; 1800 1801 page = pte_page(pte); 1802 if (pte_dirty(pte)) 1803 set_page_dirty(page); 1804 list_add(&page->lru, &page_list); 1805 } 1806 spin_unlock(&mm->page_table_lock); 1807 flush_tlb_range(vma, start, end); 1808 mmu_notifier_invalidate_range_end(mm, start, end); 1809 list_for_each_entry_safe(page, tmp, &page_list, lru) { 1810 list_del(&page->lru); 1811 put_page(page); 1812 } 1813} 1814 1815void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 1816 unsigned long end, struct page *ref_page) 1817{ 1818 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 1819 __unmap_hugepage_range(vma, start, end, ref_page); 1820 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 1821} 1822 1823/* 1824 * This is called when the original mapper is failing to COW a MAP_PRIVATE 1825 * mappping it owns the reserve page for. The intention is to unmap the page 1826 * from other VMAs and let the children be SIGKILLed if they are faulting the 1827 * same region. 1828 */ 1829static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 1830 struct page *page, unsigned long address) 1831{ 1832 struct hstate *h = hstate_vma(vma); 1833 struct vm_area_struct *iter_vma; 1834 struct address_space *mapping; 1835 struct prio_tree_iter iter; 1836 pgoff_t pgoff; 1837 1838 /* 1839 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 1840 * from page cache lookup which is in HPAGE_SIZE units. 1841 */ 1842 address = address & huge_page_mask(h); 1843 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) 1844 + (vma->vm_pgoff >> PAGE_SHIFT); 1845 mapping = (struct address_space *)page_private(page); 1846 1847 vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { 1848 /* Do not unmap the current VMA */ 1849 if (iter_vma == vma) 1850 continue; 1851 1852 /* 1853 * Unmap the page from other VMAs without their own reserves. 1854 * They get marked to be SIGKILLed if they fault in these 1855 * areas. This is because a future no-page fault on this VMA 1856 * could insert a zeroed page instead of the data existing 1857 * from the time of fork. This would look like data corruption 1858 */ 1859 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 1860 unmap_hugepage_range(iter_vma, 1861 address, address + huge_page_size(h), 1862 page); 1863 } 1864 1865 return 1; 1866} 1867 1868static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 1869 unsigned long address, pte_t *ptep, pte_t pte, 1870 struct page *pagecache_page) 1871{ 1872 struct hstate *h = hstate_vma(vma); 1873 struct page *old_page, *new_page; 1874 int avoidcopy; 1875 int outside_reserve = 0; 1876 1877 old_page = pte_page(pte); 1878 1879retry_avoidcopy: 1880 /* If no-one else is actually using this page, avoid the copy 1881 * and just make the page writable */ 1882 avoidcopy = (page_count(old_page) == 1); 1883 if (avoidcopy) { 1884 set_huge_ptep_writable(vma, address, ptep); 1885 return 0; 1886 } 1887 1888 /* 1889 * If the process that created a MAP_PRIVATE mapping is about to 1890 * perform a COW due to a shared page count, attempt to satisfy 1891 * the allocation without using the existing reserves. The pagecache 1892 * page is used to determine if the reserve at this address was 1893 * consumed or not. If reserves were used, a partial faulted mapping 1894 * at the time of fork() could consume its reserves on COW instead 1895 * of the full address range. 1896 */ 1897 if (!(vma->vm_flags & VM_SHARED) && 1898 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 1899 old_page != pagecache_page) 1900 outside_reserve = 1; 1901 1902 page_cache_get(old_page); 1903 new_page = alloc_huge_page(vma, address, outside_reserve); 1904 1905 if (IS_ERR(new_page)) { 1906 page_cache_release(old_page); 1907 1908 /* 1909 * If a process owning a MAP_PRIVATE mapping fails to COW, 1910 * it is due to references held by a child and an insufficient 1911 * huge page pool. To guarantee the original mappers 1912 * reliability, unmap the page from child processes. The child 1913 * may get SIGKILLed if it later faults. 1914 */ 1915 if (outside_reserve) { 1916 BUG_ON(huge_pte_none(pte)); 1917 if (unmap_ref_private(mm, vma, old_page, address)) { 1918 BUG_ON(page_count(old_page) != 1); 1919 BUG_ON(huge_pte_none(pte)); 1920 goto retry_avoidcopy; 1921 } 1922 WARN_ON_ONCE(1); 1923 } 1924 1925 return -PTR_ERR(new_page); 1926 } 1927 1928 spin_unlock(&mm->page_table_lock); 1929 copy_huge_page(new_page, old_page, address, vma); 1930 __SetPageUptodate(new_page); 1931 spin_lock(&mm->page_table_lock); 1932 1933 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 1934 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 1935 /* Break COW */ 1936 huge_ptep_clear_flush(vma, address, ptep); 1937 set_huge_pte_at(mm, address, ptep, 1938 make_huge_pte(vma, new_page, 1)); 1939 /* Make the old page be freed below */ 1940 new_page = old_page; 1941 } 1942 page_cache_release(new_page); 1943 page_cache_release(old_page); 1944 return 0; 1945} 1946 1947/* Return the pagecache page at a given address within a VMA */ 1948static struct page *hugetlbfs_pagecache_page(struct hstate *h, 1949 struct vm_area_struct *vma, unsigned long address) 1950{ 1951 struct address_space *mapping; 1952 pgoff_t idx; 1953 1954 mapping = vma->vm_file->f_mapping; 1955 idx = vma_hugecache_offset(h, vma, address); 1956 1957 return find_lock_page(mapping, idx); 1958} 1959 1960static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 1961 unsigned long address, pte_t *ptep, int write_access) 1962{ 1963 struct hstate *h = hstate_vma(vma); 1964 int ret = VM_FAULT_SIGBUS; 1965 pgoff_t idx; 1966 unsigned long size; 1967 struct page *page; 1968 struct address_space *mapping; 1969 pte_t new_pte; 1970 1971 /* 1972 * Currently, we are forced to kill the process in the event the 1973 * original mapper has unmapped pages from the child due to a failed 1974 * COW. Warn that such a situation has occured as it may not be obvious 1975 */ 1976 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 1977 printk(KERN_WARNING 1978 "PID %d killed due to inadequate hugepage pool\n", 1979 current->pid); 1980 return ret; 1981 } 1982 1983 mapping = vma->vm_file->f_mapping; 1984 idx = vma_hugecache_offset(h, vma, address); 1985 1986 /* 1987 * Use page lock to guard against racing truncation 1988 * before we get page_table_lock. 1989 */ 1990retry: 1991 page = find_lock_page(mapping, idx); 1992 if (!page) { 1993 size = i_size_read(mapping->host) >> huge_page_shift(h); 1994 if (idx >= size) 1995 goto out; 1996 page = alloc_huge_page(vma, address, 0); 1997 if (IS_ERR(page)) { 1998 ret = -PTR_ERR(page); 1999 goto out; 2000 } 2001 clear_huge_page(page, address, huge_page_size(h)); 2002 __SetPageUptodate(page); 2003 2004 if (vma->vm_flags & VM_SHARED) { 2005 int err; 2006 struct inode *inode = mapping->host; 2007 2008 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2009 if (err) { 2010 put_page(page); 2011 if (err == -EEXIST) 2012 goto retry; 2013 goto out; 2014 } 2015 2016 spin_lock(&inode->i_lock); 2017 inode->i_blocks += blocks_per_huge_page(h); 2018 spin_unlock(&inode->i_lock); 2019 } else 2020 lock_page(page); 2021 } 2022 2023 /* 2024 * If we are going to COW a private mapping later, we examine the 2025 * pending reservations for this page now. This will ensure that 2026 * any allocations necessary to record that reservation occur outside 2027 * the spinlock. 2028 */ 2029 if (write_access && !(vma->vm_flags & VM_SHARED)) 2030 if (vma_needs_reservation(h, vma, address) < 0) { 2031 ret = VM_FAULT_OOM; 2032 goto backout_unlocked; 2033 } 2034 2035 spin_lock(&mm->page_table_lock); 2036 size = i_size_read(mapping->host) >> huge_page_shift(h); 2037 if (idx >= size) 2038 goto backout; 2039 2040 ret = 0; 2041 if (!huge_pte_none(huge_ptep_get(ptep))) 2042 goto backout; 2043 2044 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2045 && (vma->vm_flags & VM_SHARED))); 2046 set_huge_pte_at(mm, address, ptep, new_pte); 2047 2048 if (write_access && !(vma->vm_flags & VM_SHARED)) { 2049 /* Optimization, do the COW without a second fault */ 2050 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2051 } 2052 2053 spin_unlock(&mm->page_table_lock); 2054 unlock_page(page); 2055out: 2056 return ret; 2057 2058backout: 2059 spin_unlock(&mm->page_table_lock); 2060backout_unlocked: 2061 unlock_page(page); 2062 put_page(page); 2063 goto out; 2064} 2065 2066int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2067 unsigned long address, int write_access) 2068{ 2069 pte_t *ptep; 2070 pte_t entry; 2071 int ret; 2072 struct page *pagecache_page = NULL; 2073 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2074 struct hstate *h = hstate_vma(vma); 2075 2076 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2077 if (!ptep) 2078 return VM_FAULT_OOM; 2079 2080 /* 2081 * Serialize hugepage allocation and instantiation, so that we don't 2082 * get spurious allocation failures if two CPUs race to instantiate 2083 * the same page in the page cache. 2084 */ 2085 mutex_lock(&hugetlb_instantiation_mutex); 2086 entry = huge_ptep_get(ptep); 2087 if (huge_pte_none(entry)) { 2088 ret = hugetlb_no_page(mm, vma, address, ptep, write_access); 2089 goto out_mutex; 2090 } 2091 2092 ret = 0; 2093 2094 /* 2095 * If we are going to COW the mapping later, we examine the pending 2096 * reservations for this page now. This will ensure that any 2097 * allocations necessary to record that reservation occur outside the 2098 * spinlock. For private mappings, we also lookup the pagecache 2099 * page now as it is used to determine if a reservation has been 2100 * consumed. 2101 */ 2102 if (write_access && !pte_write(entry)) { 2103 if (vma_needs_reservation(h, vma, address) < 0) { 2104 ret = VM_FAULT_OOM; 2105 goto out_mutex; 2106 } 2107 2108 if (!(vma->vm_flags & VM_SHARED)) 2109 pagecache_page = hugetlbfs_pagecache_page(h, 2110 vma, address); 2111 } 2112 2113 spin_lock(&mm->page_table_lock); 2114 /* Check for a racing update before calling hugetlb_cow */ 2115 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2116 goto out_page_table_lock; 2117 2118 2119 if (write_access) { 2120 if (!pte_write(entry)) { 2121 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2122 pagecache_page); 2123 goto out_page_table_lock; 2124 } 2125 entry = pte_mkdirty(entry); 2126 } 2127 entry = pte_mkyoung(entry); 2128 if (huge_ptep_set_access_flags(vma, address, ptep, entry, write_access)) 2129 update_mmu_cache(vma, address, entry); 2130 2131out_page_table_lock: 2132 spin_unlock(&mm->page_table_lock); 2133 2134 if (pagecache_page) { 2135 unlock_page(pagecache_page); 2136 put_page(pagecache_page); 2137 } 2138 2139out_mutex: 2140 mutex_unlock(&hugetlb_instantiation_mutex); 2141 2142 return ret; 2143} 2144 2145/* Can be overriden by architectures */ 2146__attribute__((weak)) struct page * 2147follow_huge_pud(struct mm_struct *mm, unsigned long address, 2148 pud_t *pud, int write) 2149{ 2150 BUG(); 2151 return NULL; 2152} 2153 2154static int huge_zeropage_ok(pte_t *ptep, int write, int shared) 2155{ 2156 if (!ptep || write || shared) 2157 return 0; 2158 else 2159 return huge_pte_none(huge_ptep_get(ptep)); 2160} 2161 2162int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2163 struct page **pages, struct vm_area_struct **vmas, 2164 unsigned long *position, int *length, int i, 2165 int write) 2166{ 2167 unsigned long pfn_offset; 2168 unsigned long vaddr = *position; 2169 int remainder = *length; 2170 struct hstate *h = hstate_vma(vma); 2171 int zeropage_ok = 0; 2172 int shared = vma->vm_flags & VM_SHARED; 2173 2174 spin_lock(&mm->page_table_lock); 2175 while (vaddr < vma->vm_end && remainder) { 2176 pte_t *pte; 2177 struct page *page; 2178 2179 /* 2180 * Some archs (sparc64, sh*) have multiple pte_ts to 2181 * each hugepage. We have to make * sure we get the 2182 * first, for the page indexing below to work. 2183 */ 2184 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2185 if (huge_zeropage_ok(pte, write, shared)) 2186 zeropage_ok = 1; 2187 2188 if (!pte || 2189 (huge_pte_none(huge_ptep_get(pte)) && !zeropage_ok) || 2190 (write && !pte_write(huge_ptep_get(pte)))) { 2191 int ret; 2192 2193 spin_unlock(&mm->page_table_lock); 2194 ret = hugetlb_fault(mm, vma, vaddr, write); 2195 spin_lock(&mm->page_table_lock); 2196 if (!(ret & VM_FAULT_ERROR)) 2197 continue; 2198 2199 remainder = 0; 2200 if (!i) 2201 i = -EFAULT; 2202 break; 2203 } 2204 2205 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2206 page = pte_page(huge_ptep_get(pte)); 2207same_page: 2208 if (pages) { 2209 if (zeropage_ok) 2210 pages[i] = ZERO_PAGE(0); 2211 else 2212 pages[i] = mem_map_offset(page, pfn_offset); 2213 get_page(pages[i]); 2214 } 2215 2216 if (vmas) 2217 vmas[i] = vma; 2218 2219 vaddr += PAGE_SIZE; 2220 ++pfn_offset; 2221 --remainder; 2222 ++i; 2223 if (vaddr < vma->vm_end && remainder && 2224 pfn_offset < pages_per_huge_page(h)) { 2225 /* 2226 * We use pfn_offset to avoid touching the pageframes 2227 * of this compound page. 2228 */ 2229 goto same_page; 2230 } 2231 } 2232 spin_unlock(&mm->page_table_lock); 2233 *length = remainder; 2234 *position = vaddr; 2235 2236 return i; 2237} 2238 2239void hugetlb_change_protection(struct vm_area_struct *vma, 2240 unsigned long address, unsigned long end, pgprot_t newprot) 2241{ 2242 struct mm_struct *mm = vma->vm_mm; 2243 unsigned long start = address; 2244 pte_t *ptep; 2245 pte_t pte; 2246 struct hstate *h = hstate_vma(vma); 2247 2248 BUG_ON(address >= end); 2249 flush_cache_range(vma, address, end); 2250 2251 spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); 2252 spin_lock(&mm->page_table_lock); 2253 for (; address < end; address += huge_page_size(h)) { 2254 ptep = huge_pte_offset(mm, address); 2255 if (!ptep) 2256 continue; 2257 if (huge_pmd_unshare(mm, &address, ptep)) 2258 continue; 2259 if (!huge_pte_none(huge_ptep_get(ptep))) { 2260 pte = huge_ptep_get_and_clear(mm, address, ptep); 2261 pte = pte_mkhuge(pte_modify(pte, newprot)); 2262 set_huge_pte_at(mm, address, ptep, pte); 2263 } 2264 } 2265 spin_unlock(&mm->page_table_lock); 2266 spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); 2267 2268 flush_tlb_range(vma, start, end); 2269} 2270 2271int hugetlb_reserve_pages(struct inode *inode, 2272 long from, long to, 2273 struct vm_area_struct *vma) 2274{ 2275 long ret, chg; 2276 struct hstate *h = hstate_inode(inode); 2277 2278 if (vma && vma->vm_flags & VM_NORESERVE) 2279 return 0; 2280 2281 /* 2282 * Shared mappings base their reservation on the number of pages that 2283 * are already allocated on behalf of the file. Private mappings need 2284 * to reserve the full area even if read-only as mprotect() may be 2285 * called to make the mapping read-write. Assume !vma is a shm mapping 2286 */ 2287 if (!vma || vma->vm_flags & VM_SHARED) 2288 chg = region_chg(&inode->i_mapping->private_list, from, to); 2289 else { 2290 struct resv_map *resv_map = resv_map_alloc(); 2291 if (!resv_map) 2292 return -ENOMEM; 2293 2294 chg = to - from; 2295 2296 set_vma_resv_map(vma, resv_map); 2297 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 2298 } 2299 2300 if (chg < 0) 2301 return chg; 2302 2303 if (hugetlb_get_quota(inode->i_mapping, chg)) 2304 return -ENOSPC; 2305 ret = hugetlb_acct_memory(h, chg); 2306 if (ret < 0) { 2307 hugetlb_put_quota(inode->i_mapping, chg); 2308 return ret; 2309 } 2310 if (!vma || vma->vm_flags & VM_SHARED) 2311 region_add(&inode->i_mapping->private_list, from, to); 2312 return 0; 2313} 2314 2315void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 2316{ 2317 struct hstate *h = hstate_inode(inode); 2318 long chg = region_truncate(&inode->i_mapping->private_list, offset); 2319 2320 spin_lock(&inode->i_lock); 2321 inode->i_blocks -= blocks_per_huge_page(h); 2322 spin_unlock(&inode->i_lock); 2323 2324 hugetlb_put_quota(inode->i_mapping, (chg - freed)); 2325 hugetlb_acct_memory(h, -(chg - freed)); 2326} 2327