hugetlb.c revision 81a6fcae3ff3f6af1c9d7e31499e68fda2b3f58d
1/* 2 * Generic hugetlb support. 3 * (C) Nadia Yvette Chambers, April 2004 4 */ 5#include <linux/list.h> 6#include <linux/init.h> 7#include <linux/module.h> 8#include <linux/mm.h> 9#include <linux/seq_file.h> 10#include <linux/sysctl.h> 11#include <linux/highmem.h> 12#include <linux/mmu_notifier.h> 13#include <linux/nodemask.h> 14#include <linux/pagemap.h> 15#include <linux/mempolicy.h> 16#include <linux/cpuset.h> 17#include <linux/mutex.h> 18#include <linux/bootmem.h> 19#include <linux/sysfs.h> 20#include <linux/slab.h> 21#include <linux/rmap.h> 22#include <linux/swap.h> 23#include <linux/swapops.h> 24 25#include <asm/page.h> 26#include <asm/pgtable.h> 27#include <asm/tlb.h> 28 29#include <linux/io.h> 30#include <linux/hugetlb.h> 31#include <linux/hugetlb_cgroup.h> 32#include <linux/node.h> 33#include "internal.h" 34 35const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 36static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 37unsigned long hugepages_treat_as_movable; 38 39int hugetlb_max_hstate __read_mostly; 40unsigned int default_hstate_idx; 41struct hstate hstates[HUGE_MAX_HSTATE]; 42 43__initdata LIST_HEAD(huge_boot_pages); 44 45/* for command line parsing */ 46static struct hstate * __initdata parsed_hstate; 47static unsigned long __initdata default_hstate_max_huge_pages; 48static unsigned long __initdata default_hstate_size; 49 50/* 51 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages 52 */ 53DEFINE_SPINLOCK(hugetlb_lock); 54 55static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) 56{ 57 bool free = (spool->count == 0) && (spool->used_hpages == 0); 58 59 spin_unlock(&spool->lock); 60 61 /* If no pages are used, and no other handles to the subpool 62 * remain, free the subpool the subpool remain */ 63 if (free) 64 kfree(spool); 65} 66 67struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) 68{ 69 struct hugepage_subpool *spool; 70 71 spool = kmalloc(sizeof(*spool), GFP_KERNEL); 72 if (!spool) 73 return NULL; 74 75 spin_lock_init(&spool->lock); 76 spool->count = 1; 77 spool->max_hpages = nr_blocks; 78 spool->used_hpages = 0; 79 80 return spool; 81} 82 83void hugepage_put_subpool(struct hugepage_subpool *spool) 84{ 85 spin_lock(&spool->lock); 86 BUG_ON(!spool->count); 87 spool->count--; 88 unlock_or_release_subpool(spool); 89} 90 91static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, 92 long delta) 93{ 94 int ret = 0; 95 96 if (!spool) 97 return 0; 98 99 spin_lock(&spool->lock); 100 if ((spool->used_hpages + delta) <= spool->max_hpages) { 101 spool->used_hpages += delta; 102 } else { 103 ret = -ENOMEM; 104 } 105 spin_unlock(&spool->lock); 106 107 return ret; 108} 109 110static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, 111 long delta) 112{ 113 if (!spool) 114 return; 115 116 spin_lock(&spool->lock); 117 spool->used_hpages -= delta; 118 /* If hugetlbfs_put_super couldn't free spool due to 119 * an outstanding quota reference, free it now. */ 120 unlock_or_release_subpool(spool); 121} 122 123static inline struct hugepage_subpool *subpool_inode(struct inode *inode) 124{ 125 return HUGETLBFS_SB(inode->i_sb)->spool; 126} 127 128static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) 129{ 130 return subpool_inode(file_inode(vma->vm_file)); 131} 132 133/* 134 * Region tracking -- allows tracking of reservations and instantiated pages 135 * across the pages in a mapping. 136 * 137 * The region data structures are protected by a combination of the mmap_sem 138 * and the hugetlb_instantiation_mutex. To access or modify a region the caller 139 * must either hold the mmap_sem for write, or the mmap_sem for read and 140 * the hugetlb_instantiation_mutex: 141 * 142 * down_write(&mm->mmap_sem); 143 * or 144 * down_read(&mm->mmap_sem); 145 * mutex_lock(&hugetlb_instantiation_mutex); 146 */ 147struct file_region { 148 struct list_head link; 149 long from; 150 long to; 151}; 152 153static long region_add(struct list_head *head, long f, long t) 154{ 155 struct file_region *rg, *nrg, *trg; 156 157 /* Locate the region we are either in or before. */ 158 list_for_each_entry(rg, head, link) 159 if (f <= rg->to) 160 break; 161 162 /* Round our left edge to the current segment if it encloses us. */ 163 if (f > rg->from) 164 f = rg->from; 165 166 /* Check for and consume any regions we now overlap with. */ 167 nrg = rg; 168 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 169 if (&rg->link == head) 170 break; 171 if (rg->from > t) 172 break; 173 174 /* If this area reaches higher then extend our area to 175 * include it completely. If this is not the first area 176 * which we intend to reuse, free it. */ 177 if (rg->to > t) 178 t = rg->to; 179 if (rg != nrg) { 180 list_del(&rg->link); 181 kfree(rg); 182 } 183 } 184 nrg->from = f; 185 nrg->to = t; 186 return 0; 187} 188 189static long region_chg(struct list_head *head, long f, long t) 190{ 191 struct file_region *rg, *nrg; 192 long chg = 0; 193 194 /* Locate the region we are before or in. */ 195 list_for_each_entry(rg, head, link) 196 if (f <= rg->to) 197 break; 198 199 /* If we are below the current region then a new region is required. 200 * Subtle, allocate a new region at the position but make it zero 201 * size such that we can guarantee to record the reservation. */ 202 if (&rg->link == head || t < rg->from) { 203 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 204 if (!nrg) 205 return -ENOMEM; 206 nrg->from = f; 207 nrg->to = f; 208 INIT_LIST_HEAD(&nrg->link); 209 list_add(&nrg->link, rg->link.prev); 210 211 return t - f; 212 } 213 214 /* Round our left edge to the current segment if it encloses us. */ 215 if (f > rg->from) 216 f = rg->from; 217 chg = t - f; 218 219 /* Check for and consume any regions we now overlap with. */ 220 list_for_each_entry(rg, rg->link.prev, link) { 221 if (&rg->link == head) 222 break; 223 if (rg->from > t) 224 return chg; 225 226 /* We overlap with this area, if it extends further than 227 * us then we must extend ourselves. Account for its 228 * existing reservation. */ 229 if (rg->to > t) { 230 chg += rg->to - t; 231 t = rg->to; 232 } 233 chg -= rg->to - rg->from; 234 } 235 return chg; 236} 237 238static long region_truncate(struct list_head *head, long end) 239{ 240 struct file_region *rg, *trg; 241 long chg = 0; 242 243 /* Locate the region we are either in or before. */ 244 list_for_each_entry(rg, head, link) 245 if (end <= rg->to) 246 break; 247 if (&rg->link == head) 248 return 0; 249 250 /* If we are in the middle of a region then adjust it. */ 251 if (end > rg->from) { 252 chg = rg->to - end; 253 rg->to = end; 254 rg = list_entry(rg->link.next, typeof(*rg), link); 255 } 256 257 /* Drop any remaining regions. */ 258 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 259 if (&rg->link == head) 260 break; 261 chg += rg->to - rg->from; 262 list_del(&rg->link); 263 kfree(rg); 264 } 265 return chg; 266} 267 268static long region_count(struct list_head *head, long f, long t) 269{ 270 struct file_region *rg; 271 long chg = 0; 272 273 /* Locate each segment we overlap with, and count that overlap. */ 274 list_for_each_entry(rg, head, link) { 275 long seg_from; 276 long seg_to; 277 278 if (rg->to <= f) 279 continue; 280 if (rg->from >= t) 281 break; 282 283 seg_from = max(rg->from, f); 284 seg_to = min(rg->to, t); 285 286 chg += seg_to - seg_from; 287 } 288 289 return chg; 290} 291 292/* 293 * Convert the address within this vma to the page offset within 294 * the mapping, in pagecache page units; huge pages here. 295 */ 296static pgoff_t vma_hugecache_offset(struct hstate *h, 297 struct vm_area_struct *vma, unsigned long address) 298{ 299 return ((address - vma->vm_start) >> huge_page_shift(h)) + 300 (vma->vm_pgoff >> huge_page_order(h)); 301} 302 303pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 304 unsigned long address) 305{ 306 return vma_hugecache_offset(hstate_vma(vma), vma, address); 307} 308 309/* 310 * Return the size of the pages allocated when backing a VMA. In the majority 311 * cases this will be same size as used by the page table entries. 312 */ 313unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) 314{ 315 struct hstate *hstate; 316 317 if (!is_vm_hugetlb_page(vma)) 318 return PAGE_SIZE; 319 320 hstate = hstate_vma(vma); 321 322 return 1UL << huge_page_shift(hstate); 323} 324EXPORT_SYMBOL_GPL(vma_kernel_pagesize); 325 326/* 327 * Return the page size being used by the MMU to back a VMA. In the majority 328 * of cases, the page size used by the kernel matches the MMU size. On 329 * architectures where it differs, an architecture-specific version of this 330 * function is required. 331 */ 332#ifndef vma_mmu_pagesize 333unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 334{ 335 return vma_kernel_pagesize(vma); 336} 337#endif 338 339/* 340 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 341 * bits of the reservation map pointer, which are always clear due to 342 * alignment. 343 */ 344#define HPAGE_RESV_OWNER (1UL << 0) 345#define HPAGE_RESV_UNMAPPED (1UL << 1) 346#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 347 348/* 349 * These helpers are used to track how many pages are reserved for 350 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 351 * is guaranteed to have their future faults succeed. 352 * 353 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 354 * the reserve counters are updated with the hugetlb_lock held. It is safe 355 * to reset the VMA at fork() time as it is not in use yet and there is no 356 * chance of the global counters getting corrupted as a result of the values. 357 * 358 * The private mapping reservation is represented in a subtly different 359 * manner to a shared mapping. A shared mapping has a region map associated 360 * with the underlying file, this region map represents the backing file 361 * pages which have ever had a reservation assigned which this persists even 362 * after the page is instantiated. A private mapping has a region map 363 * associated with the original mmap which is attached to all VMAs which 364 * reference it, this region map represents those offsets which have consumed 365 * reservation ie. where pages have been instantiated. 366 */ 367static unsigned long get_vma_private_data(struct vm_area_struct *vma) 368{ 369 return (unsigned long)vma->vm_private_data; 370} 371 372static void set_vma_private_data(struct vm_area_struct *vma, 373 unsigned long value) 374{ 375 vma->vm_private_data = (void *)value; 376} 377 378struct resv_map { 379 struct kref refs; 380 struct list_head regions; 381}; 382 383static struct resv_map *resv_map_alloc(void) 384{ 385 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 386 if (!resv_map) 387 return NULL; 388 389 kref_init(&resv_map->refs); 390 INIT_LIST_HEAD(&resv_map->regions); 391 392 return resv_map; 393} 394 395static void resv_map_release(struct kref *ref) 396{ 397 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 398 399 /* Clear out any active regions before we release the map. */ 400 region_truncate(&resv_map->regions, 0); 401 kfree(resv_map); 402} 403 404static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 405{ 406 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 407 if (!(vma->vm_flags & VM_MAYSHARE)) 408 return (struct resv_map *)(get_vma_private_data(vma) & 409 ~HPAGE_RESV_MASK); 410 return NULL; 411} 412 413static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 414{ 415 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 416 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 417 418 set_vma_private_data(vma, (get_vma_private_data(vma) & 419 HPAGE_RESV_MASK) | (unsigned long)map); 420} 421 422static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 423{ 424 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 425 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 426 427 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 428} 429 430static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 431{ 432 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 433 434 return (get_vma_private_data(vma) & flag) != 0; 435} 436 437/* Decrement the reserved pages in the hugepage pool by one */ 438static void decrement_hugepage_resv_vma(struct hstate *h, 439 struct vm_area_struct *vma) 440{ 441 if (vma->vm_flags & VM_NORESERVE) 442 return; 443 444 if (vma->vm_flags & VM_MAYSHARE) { 445 /* Shared mappings always use reserves */ 446 h->resv_huge_pages--; 447 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 448 /* 449 * Only the process that called mmap() has reserves for 450 * private mappings. 451 */ 452 h->resv_huge_pages--; 453 } 454} 455 456/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 457void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 458{ 459 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 460 if (!(vma->vm_flags & VM_MAYSHARE)) 461 vma->vm_private_data = (void *)0; 462} 463 464/* Returns true if the VMA has associated reserve pages */ 465static int vma_has_reserves(struct vm_area_struct *vma) 466{ 467 if (vma->vm_flags & VM_MAYSHARE) 468 return 1; 469 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 470 return 1; 471 return 0; 472} 473 474static void copy_gigantic_page(struct page *dst, struct page *src) 475{ 476 int i; 477 struct hstate *h = page_hstate(src); 478 struct page *dst_base = dst; 479 struct page *src_base = src; 480 481 for (i = 0; i < pages_per_huge_page(h); ) { 482 cond_resched(); 483 copy_highpage(dst, src); 484 485 i++; 486 dst = mem_map_next(dst, dst_base, i); 487 src = mem_map_next(src, src_base, i); 488 } 489} 490 491void copy_huge_page(struct page *dst, struct page *src) 492{ 493 int i; 494 struct hstate *h = page_hstate(src); 495 496 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 497 copy_gigantic_page(dst, src); 498 return; 499 } 500 501 might_sleep(); 502 for (i = 0; i < pages_per_huge_page(h); i++) { 503 cond_resched(); 504 copy_highpage(dst + i, src + i); 505 } 506} 507 508static void enqueue_huge_page(struct hstate *h, struct page *page) 509{ 510 int nid = page_to_nid(page); 511 list_move(&page->lru, &h->hugepage_freelists[nid]); 512 h->free_huge_pages++; 513 h->free_huge_pages_node[nid]++; 514} 515 516static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 517{ 518 struct page *page; 519 520 if (list_empty(&h->hugepage_freelists[nid])) 521 return NULL; 522 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); 523 list_move(&page->lru, &h->hugepage_activelist); 524 set_page_refcounted(page); 525 h->free_huge_pages--; 526 h->free_huge_pages_node[nid]--; 527 return page; 528} 529 530static struct page *dequeue_huge_page_vma(struct hstate *h, 531 struct vm_area_struct *vma, 532 unsigned long address, int avoid_reserve) 533{ 534 struct page *page = NULL; 535 struct mempolicy *mpol; 536 nodemask_t *nodemask; 537 struct zonelist *zonelist; 538 struct zone *zone; 539 struct zoneref *z; 540 unsigned int cpuset_mems_cookie; 541 542 /* 543 * A child process with MAP_PRIVATE mappings created by their parent 544 * have no page reserves. This check ensures that reservations are 545 * not "stolen". The child may still get SIGKILLed 546 */ 547 if (!vma_has_reserves(vma) && 548 h->free_huge_pages - h->resv_huge_pages == 0) 549 goto err; 550 551 /* If reserves cannot be used, ensure enough pages are in the pool */ 552 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 553 goto err; 554 555retry_cpuset: 556 cpuset_mems_cookie = get_mems_allowed(); 557 zonelist = huge_zonelist(vma, address, 558 htlb_alloc_mask, &mpol, &nodemask); 559 560 for_each_zone_zonelist_nodemask(zone, z, zonelist, 561 MAX_NR_ZONES - 1, nodemask) { 562 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { 563 page = dequeue_huge_page_node(h, zone_to_nid(zone)); 564 if (page) { 565 if (!avoid_reserve) 566 decrement_hugepage_resv_vma(h, vma); 567 break; 568 } 569 } 570 } 571 572 mpol_cond_put(mpol); 573 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page)) 574 goto retry_cpuset; 575 return page; 576 577err: 578 return NULL; 579} 580 581static void update_and_free_page(struct hstate *h, struct page *page) 582{ 583 int i; 584 585 VM_BUG_ON(h->order >= MAX_ORDER); 586 587 h->nr_huge_pages--; 588 h->nr_huge_pages_node[page_to_nid(page)]--; 589 for (i = 0; i < pages_per_huge_page(h); i++) { 590 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 591 1 << PG_referenced | 1 << PG_dirty | 592 1 << PG_active | 1 << PG_reserved | 593 1 << PG_private | 1 << PG_writeback); 594 } 595 VM_BUG_ON(hugetlb_cgroup_from_page(page)); 596 set_compound_page_dtor(page, NULL); 597 set_page_refcounted(page); 598 arch_release_hugepage(page); 599 __free_pages(page, huge_page_order(h)); 600} 601 602struct hstate *size_to_hstate(unsigned long size) 603{ 604 struct hstate *h; 605 606 for_each_hstate(h) { 607 if (huge_page_size(h) == size) 608 return h; 609 } 610 return NULL; 611} 612 613static void free_huge_page(struct page *page) 614{ 615 /* 616 * Can't pass hstate in here because it is called from the 617 * compound page destructor. 618 */ 619 struct hstate *h = page_hstate(page); 620 int nid = page_to_nid(page); 621 struct hugepage_subpool *spool = 622 (struct hugepage_subpool *)page_private(page); 623 624 set_page_private(page, 0); 625 page->mapping = NULL; 626 BUG_ON(page_count(page)); 627 BUG_ON(page_mapcount(page)); 628 629 spin_lock(&hugetlb_lock); 630 hugetlb_cgroup_uncharge_page(hstate_index(h), 631 pages_per_huge_page(h), page); 632 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 633 /* remove the page from active list */ 634 list_del(&page->lru); 635 update_and_free_page(h, page); 636 h->surplus_huge_pages--; 637 h->surplus_huge_pages_node[nid]--; 638 } else { 639 arch_clear_hugepage_flags(page); 640 enqueue_huge_page(h, page); 641 } 642 spin_unlock(&hugetlb_lock); 643 hugepage_subpool_put_pages(spool, 1); 644} 645 646static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 647{ 648 INIT_LIST_HEAD(&page->lru); 649 set_compound_page_dtor(page, free_huge_page); 650 spin_lock(&hugetlb_lock); 651 set_hugetlb_cgroup(page, NULL); 652 h->nr_huge_pages++; 653 h->nr_huge_pages_node[nid]++; 654 spin_unlock(&hugetlb_lock); 655 put_page(page); /* free it into the hugepage allocator */ 656} 657 658static void prep_compound_gigantic_page(struct page *page, unsigned long order) 659{ 660 int i; 661 int nr_pages = 1 << order; 662 struct page *p = page + 1; 663 664 /* we rely on prep_new_huge_page to set the destructor */ 665 set_compound_order(page, order); 666 __SetPageHead(page); 667 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 668 __SetPageTail(p); 669 set_page_count(p, 0); 670 p->first_page = page; 671 } 672} 673 674/* 675 * PageHuge() only returns true for hugetlbfs pages, but not for normal or 676 * transparent huge pages. See the PageTransHuge() documentation for more 677 * details. 678 */ 679int PageHuge(struct page *page) 680{ 681 compound_page_dtor *dtor; 682 683 if (!PageCompound(page)) 684 return 0; 685 686 page = compound_head(page); 687 dtor = get_compound_page_dtor(page); 688 689 return dtor == free_huge_page; 690} 691EXPORT_SYMBOL_GPL(PageHuge); 692 693pgoff_t __basepage_index(struct page *page) 694{ 695 struct page *page_head = compound_head(page); 696 pgoff_t index = page_index(page_head); 697 unsigned long compound_idx; 698 699 if (!PageHuge(page_head)) 700 return page_index(page); 701 702 if (compound_order(page_head) >= MAX_ORDER) 703 compound_idx = page_to_pfn(page) - page_to_pfn(page_head); 704 else 705 compound_idx = page - page_head; 706 707 return (index << compound_order(page_head)) + compound_idx; 708} 709 710static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 711{ 712 struct page *page; 713 714 if (h->order >= MAX_ORDER) 715 return NULL; 716 717 page = alloc_pages_exact_node(nid, 718 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 719 __GFP_REPEAT|__GFP_NOWARN, 720 huge_page_order(h)); 721 if (page) { 722 if (arch_prepare_hugepage(page)) { 723 __free_pages(page, huge_page_order(h)); 724 return NULL; 725 } 726 prep_new_huge_page(h, page, nid); 727 } 728 729 return page; 730} 731 732/* 733 * common helper functions for hstate_next_node_to_{alloc|free}. 734 * We may have allocated or freed a huge page based on a different 735 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 736 * be outside of *nodes_allowed. Ensure that we use an allowed 737 * node for alloc or free. 738 */ 739static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 740{ 741 nid = next_node(nid, *nodes_allowed); 742 if (nid == MAX_NUMNODES) 743 nid = first_node(*nodes_allowed); 744 VM_BUG_ON(nid >= MAX_NUMNODES); 745 746 return nid; 747} 748 749static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 750{ 751 if (!node_isset(nid, *nodes_allowed)) 752 nid = next_node_allowed(nid, nodes_allowed); 753 return nid; 754} 755 756/* 757 * returns the previously saved node ["this node"] from which to 758 * allocate a persistent huge page for the pool and advance the 759 * next node from which to allocate, handling wrap at end of node 760 * mask. 761 */ 762static int hstate_next_node_to_alloc(struct hstate *h, 763 nodemask_t *nodes_allowed) 764{ 765 int nid; 766 767 VM_BUG_ON(!nodes_allowed); 768 769 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 770 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 771 772 return nid; 773} 774 775static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 776{ 777 struct page *page; 778 int start_nid; 779 int next_nid; 780 int ret = 0; 781 782 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 783 next_nid = start_nid; 784 785 do { 786 page = alloc_fresh_huge_page_node(h, next_nid); 787 if (page) { 788 ret = 1; 789 break; 790 } 791 next_nid = hstate_next_node_to_alloc(h, nodes_allowed); 792 } while (next_nid != start_nid); 793 794 if (ret) 795 count_vm_event(HTLB_BUDDY_PGALLOC); 796 else 797 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 798 799 return ret; 800} 801 802/* 803 * helper for free_pool_huge_page() - return the previously saved 804 * node ["this node"] from which to free a huge page. Advance the 805 * next node id whether or not we find a free huge page to free so 806 * that the next attempt to free addresses the next node. 807 */ 808static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 809{ 810 int nid; 811 812 VM_BUG_ON(!nodes_allowed); 813 814 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 815 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 816 817 return nid; 818} 819 820/* 821 * Free huge page from pool from next node to free. 822 * Attempt to keep persistent huge pages more or less 823 * balanced over allowed nodes. 824 * Called with hugetlb_lock locked. 825 */ 826static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 827 bool acct_surplus) 828{ 829 int start_nid; 830 int next_nid; 831 int ret = 0; 832 833 start_nid = hstate_next_node_to_free(h, nodes_allowed); 834 next_nid = start_nid; 835 836 do { 837 /* 838 * If we're returning unused surplus pages, only examine 839 * nodes with surplus pages. 840 */ 841 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && 842 !list_empty(&h->hugepage_freelists[next_nid])) { 843 struct page *page = 844 list_entry(h->hugepage_freelists[next_nid].next, 845 struct page, lru); 846 list_del(&page->lru); 847 h->free_huge_pages--; 848 h->free_huge_pages_node[next_nid]--; 849 if (acct_surplus) { 850 h->surplus_huge_pages--; 851 h->surplus_huge_pages_node[next_nid]--; 852 } 853 update_and_free_page(h, page); 854 ret = 1; 855 break; 856 } 857 next_nid = hstate_next_node_to_free(h, nodes_allowed); 858 } while (next_nid != start_nid); 859 860 return ret; 861} 862 863static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) 864{ 865 struct page *page; 866 unsigned int r_nid; 867 868 if (h->order >= MAX_ORDER) 869 return NULL; 870 871 /* 872 * Assume we will successfully allocate the surplus page to 873 * prevent racing processes from causing the surplus to exceed 874 * overcommit 875 * 876 * This however introduces a different race, where a process B 877 * tries to grow the static hugepage pool while alloc_pages() is 878 * called by process A. B will only examine the per-node 879 * counters in determining if surplus huge pages can be 880 * converted to normal huge pages in adjust_pool_surplus(). A 881 * won't be able to increment the per-node counter, until the 882 * lock is dropped by B, but B doesn't drop hugetlb_lock until 883 * no more huge pages can be converted from surplus to normal 884 * state (and doesn't try to convert again). Thus, we have a 885 * case where a surplus huge page exists, the pool is grown, and 886 * the surplus huge page still exists after, even though it 887 * should just have been converted to a normal huge page. This 888 * does not leak memory, though, as the hugepage will be freed 889 * once it is out of use. It also does not allow the counters to 890 * go out of whack in adjust_pool_surplus() as we don't modify 891 * the node values until we've gotten the hugepage and only the 892 * per-node value is checked there. 893 */ 894 spin_lock(&hugetlb_lock); 895 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 896 spin_unlock(&hugetlb_lock); 897 return NULL; 898 } else { 899 h->nr_huge_pages++; 900 h->surplus_huge_pages++; 901 } 902 spin_unlock(&hugetlb_lock); 903 904 if (nid == NUMA_NO_NODE) 905 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 906 __GFP_REPEAT|__GFP_NOWARN, 907 huge_page_order(h)); 908 else 909 page = alloc_pages_exact_node(nid, 910 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 911 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); 912 913 if (page && arch_prepare_hugepage(page)) { 914 __free_pages(page, huge_page_order(h)); 915 page = NULL; 916 } 917 918 spin_lock(&hugetlb_lock); 919 if (page) { 920 INIT_LIST_HEAD(&page->lru); 921 r_nid = page_to_nid(page); 922 set_compound_page_dtor(page, free_huge_page); 923 set_hugetlb_cgroup(page, NULL); 924 /* 925 * We incremented the global counters already 926 */ 927 h->nr_huge_pages_node[r_nid]++; 928 h->surplus_huge_pages_node[r_nid]++; 929 __count_vm_event(HTLB_BUDDY_PGALLOC); 930 } else { 931 h->nr_huge_pages--; 932 h->surplus_huge_pages--; 933 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 934 } 935 spin_unlock(&hugetlb_lock); 936 937 return page; 938} 939 940/* 941 * This allocation function is useful in the context where vma is irrelevant. 942 * E.g. soft-offlining uses this function because it only cares physical 943 * address of error page. 944 */ 945struct page *alloc_huge_page_node(struct hstate *h, int nid) 946{ 947 struct page *page; 948 949 spin_lock(&hugetlb_lock); 950 page = dequeue_huge_page_node(h, nid); 951 spin_unlock(&hugetlb_lock); 952 953 if (!page) 954 page = alloc_buddy_huge_page(h, nid); 955 956 return page; 957} 958 959/* 960 * Increase the hugetlb pool such that it can accommodate a reservation 961 * of size 'delta'. 962 */ 963static int gather_surplus_pages(struct hstate *h, int delta) 964{ 965 struct list_head surplus_list; 966 struct page *page, *tmp; 967 int ret, i; 968 int needed, allocated; 969 bool alloc_ok = true; 970 971 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 972 if (needed <= 0) { 973 h->resv_huge_pages += delta; 974 return 0; 975 } 976 977 allocated = 0; 978 INIT_LIST_HEAD(&surplus_list); 979 980 ret = -ENOMEM; 981retry: 982 spin_unlock(&hugetlb_lock); 983 for (i = 0; i < needed; i++) { 984 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 985 if (!page) { 986 alloc_ok = false; 987 break; 988 } 989 list_add(&page->lru, &surplus_list); 990 } 991 allocated += i; 992 993 /* 994 * After retaking hugetlb_lock, we need to recalculate 'needed' 995 * because either resv_huge_pages or free_huge_pages may have changed. 996 */ 997 spin_lock(&hugetlb_lock); 998 needed = (h->resv_huge_pages + delta) - 999 (h->free_huge_pages + allocated); 1000 if (needed > 0) { 1001 if (alloc_ok) 1002 goto retry; 1003 /* 1004 * We were not able to allocate enough pages to 1005 * satisfy the entire reservation so we free what 1006 * we've allocated so far. 1007 */ 1008 goto free; 1009 } 1010 /* 1011 * The surplus_list now contains _at_least_ the number of extra pages 1012 * needed to accommodate the reservation. Add the appropriate number 1013 * of pages to the hugetlb pool and free the extras back to the buddy 1014 * allocator. Commit the entire reservation here to prevent another 1015 * process from stealing the pages as they are added to the pool but 1016 * before they are reserved. 1017 */ 1018 needed += allocated; 1019 h->resv_huge_pages += delta; 1020 ret = 0; 1021 1022 /* Free the needed pages to the hugetlb pool */ 1023 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1024 if ((--needed) < 0) 1025 break; 1026 /* 1027 * This page is now managed by the hugetlb allocator and has 1028 * no users -- drop the buddy allocator's reference. 1029 */ 1030 put_page_testzero(page); 1031 VM_BUG_ON(page_count(page)); 1032 enqueue_huge_page(h, page); 1033 } 1034free: 1035 spin_unlock(&hugetlb_lock); 1036 1037 /* Free unnecessary surplus pages to the buddy allocator */ 1038 if (!list_empty(&surplus_list)) { 1039 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1040 put_page(page); 1041 } 1042 } 1043 spin_lock(&hugetlb_lock); 1044 1045 return ret; 1046} 1047 1048/* 1049 * When releasing a hugetlb pool reservation, any surplus pages that were 1050 * allocated to satisfy the reservation must be explicitly freed if they were 1051 * never used. 1052 * Called with hugetlb_lock held. 1053 */ 1054static void return_unused_surplus_pages(struct hstate *h, 1055 unsigned long unused_resv_pages) 1056{ 1057 unsigned long nr_pages; 1058 1059 /* Uncommit the reservation */ 1060 h->resv_huge_pages -= unused_resv_pages; 1061 1062 /* Cannot return gigantic pages currently */ 1063 if (h->order >= MAX_ORDER) 1064 return; 1065 1066 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 1067 1068 /* 1069 * We want to release as many surplus pages as possible, spread 1070 * evenly across all nodes with memory. Iterate across these nodes 1071 * until we can no longer free unreserved surplus pages. This occurs 1072 * when the nodes with surplus pages have no free pages. 1073 * free_pool_huge_page() will balance the the freed pages across the 1074 * on-line nodes with memory and will handle the hstate accounting. 1075 */ 1076 while (nr_pages--) { 1077 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) 1078 break; 1079 } 1080} 1081 1082/* 1083 * Determine if the huge page at addr within the vma has an associated 1084 * reservation. Where it does not we will need to logically increase 1085 * reservation and actually increase subpool usage before an allocation 1086 * can occur. Where any new reservation would be required the 1087 * reservation change is prepared, but not committed. Once the page 1088 * has been allocated from the subpool and instantiated the change should 1089 * be committed via vma_commit_reservation. No action is required on 1090 * failure. 1091 */ 1092static long vma_needs_reservation(struct hstate *h, 1093 struct vm_area_struct *vma, unsigned long addr) 1094{ 1095 struct address_space *mapping = vma->vm_file->f_mapping; 1096 struct inode *inode = mapping->host; 1097 1098 if (vma->vm_flags & VM_MAYSHARE) { 1099 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1100 return region_chg(&inode->i_mapping->private_list, 1101 idx, idx + 1); 1102 1103 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1104 return 1; 1105 1106 } else { 1107 long err; 1108 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1109 struct resv_map *reservations = vma_resv_map(vma); 1110 1111 err = region_chg(&reservations->regions, idx, idx + 1); 1112 if (err < 0) 1113 return err; 1114 return 0; 1115 } 1116} 1117static void vma_commit_reservation(struct hstate *h, 1118 struct vm_area_struct *vma, unsigned long addr) 1119{ 1120 struct address_space *mapping = vma->vm_file->f_mapping; 1121 struct inode *inode = mapping->host; 1122 1123 if (vma->vm_flags & VM_MAYSHARE) { 1124 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1125 region_add(&inode->i_mapping->private_list, idx, idx + 1); 1126 1127 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1128 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1129 struct resv_map *reservations = vma_resv_map(vma); 1130 1131 /* Mark this page used in the map. */ 1132 region_add(&reservations->regions, idx, idx + 1); 1133 } 1134} 1135 1136static struct page *alloc_huge_page(struct vm_area_struct *vma, 1137 unsigned long addr, int avoid_reserve) 1138{ 1139 struct hugepage_subpool *spool = subpool_vma(vma); 1140 struct hstate *h = hstate_vma(vma); 1141 struct page *page; 1142 long chg; 1143 int ret, idx; 1144 struct hugetlb_cgroup *h_cg; 1145 1146 idx = hstate_index(h); 1147 /* 1148 * Processes that did not create the mapping will have no 1149 * reserves and will not have accounted against subpool 1150 * limit. Check that the subpool limit can be made before 1151 * satisfying the allocation MAP_NORESERVE mappings may also 1152 * need pages and subpool limit allocated allocated if no reserve 1153 * mapping overlaps. 1154 */ 1155 chg = vma_needs_reservation(h, vma, addr); 1156 if (chg < 0) 1157 return ERR_PTR(-ENOMEM); 1158 if (chg) 1159 if (hugepage_subpool_get_pages(spool, chg)) 1160 return ERR_PTR(-ENOSPC); 1161 1162 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); 1163 if (ret) { 1164 hugepage_subpool_put_pages(spool, chg); 1165 return ERR_PTR(-ENOSPC); 1166 } 1167 spin_lock(&hugetlb_lock); 1168 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 1169 if (!page) { 1170 spin_unlock(&hugetlb_lock); 1171 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1172 if (!page) { 1173 hugetlb_cgroup_uncharge_cgroup(idx, 1174 pages_per_huge_page(h), 1175 h_cg); 1176 hugepage_subpool_put_pages(spool, chg); 1177 return ERR_PTR(-ENOSPC); 1178 } 1179 spin_lock(&hugetlb_lock); 1180 list_move(&page->lru, &h->hugepage_activelist); 1181 /* Fall through */ 1182 } 1183 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); 1184 spin_unlock(&hugetlb_lock); 1185 1186 set_page_private(page, (unsigned long)spool); 1187 1188 vma_commit_reservation(h, vma, addr); 1189 return page; 1190} 1191 1192int __weak alloc_bootmem_huge_page(struct hstate *h) 1193{ 1194 struct huge_bootmem_page *m; 1195 int nr_nodes = nodes_weight(node_states[N_MEMORY]); 1196 1197 while (nr_nodes) { 1198 void *addr; 1199 1200 addr = __alloc_bootmem_node_nopanic( 1201 NODE_DATA(hstate_next_node_to_alloc(h, 1202 &node_states[N_MEMORY])), 1203 huge_page_size(h), huge_page_size(h), 0); 1204 1205 if (addr) { 1206 /* 1207 * Use the beginning of the huge page to store the 1208 * huge_bootmem_page struct (until gather_bootmem 1209 * puts them into the mem_map). 1210 */ 1211 m = addr; 1212 goto found; 1213 } 1214 nr_nodes--; 1215 } 1216 return 0; 1217 1218found: 1219 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1220 /* Put them into a private list first because mem_map is not up yet */ 1221 list_add(&m->list, &huge_boot_pages); 1222 m->hstate = h; 1223 return 1; 1224} 1225 1226static void prep_compound_huge_page(struct page *page, int order) 1227{ 1228 if (unlikely(order > (MAX_ORDER - 1))) 1229 prep_compound_gigantic_page(page, order); 1230 else 1231 prep_compound_page(page, order); 1232} 1233 1234/* Put bootmem huge pages into the standard lists after mem_map is up */ 1235static void __init gather_bootmem_prealloc(void) 1236{ 1237 struct huge_bootmem_page *m; 1238 1239 list_for_each_entry(m, &huge_boot_pages, list) { 1240 struct hstate *h = m->hstate; 1241 struct page *page; 1242 1243#ifdef CONFIG_HIGHMEM 1244 page = pfn_to_page(m->phys >> PAGE_SHIFT); 1245 free_bootmem_late((unsigned long)m, 1246 sizeof(struct huge_bootmem_page)); 1247#else 1248 page = virt_to_page(m); 1249#endif 1250 __ClearPageReserved(page); 1251 WARN_ON(page_count(page) != 1); 1252 prep_compound_huge_page(page, h->order); 1253 prep_new_huge_page(h, page, page_to_nid(page)); 1254 /* 1255 * If we had gigantic hugepages allocated at boot time, we need 1256 * to restore the 'stolen' pages to totalram_pages in order to 1257 * fix confusing memory reports from free(1) and another 1258 * side-effects, like CommitLimit going negative. 1259 */ 1260 if (h->order > (MAX_ORDER - 1)) 1261 adjust_managed_page_count(page, 1 << h->order); 1262 } 1263} 1264 1265static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1266{ 1267 unsigned long i; 1268 1269 for (i = 0; i < h->max_huge_pages; ++i) { 1270 if (h->order >= MAX_ORDER) { 1271 if (!alloc_bootmem_huge_page(h)) 1272 break; 1273 } else if (!alloc_fresh_huge_page(h, 1274 &node_states[N_MEMORY])) 1275 break; 1276 } 1277 h->max_huge_pages = i; 1278} 1279 1280static void __init hugetlb_init_hstates(void) 1281{ 1282 struct hstate *h; 1283 1284 for_each_hstate(h) { 1285 /* oversize hugepages were init'ed in early boot */ 1286 if (h->order < MAX_ORDER) 1287 hugetlb_hstate_alloc_pages(h); 1288 } 1289} 1290 1291static char * __init memfmt(char *buf, unsigned long n) 1292{ 1293 if (n >= (1UL << 30)) 1294 sprintf(buf, "%lu GB", n >> 30); 1295 else if (n >= (1UL << 20)) 1296 sprintf(buf, "%lu MB", n >> 20); 1297 else 1298 sprintf(buf, "%lu KB", n >> 10); 1299 return buf; 1300} 1301 1302static void __init report_hugepages(void) 1303{ 1304 struct hstate *h; 1305 1306 for_each_hstate(h) { 1307 char buf[32]; 1308 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", 1309 memfmt(buf, huge_page_size(h)), 1310 h->free_huge_pages); 1311 } 1312} 1313 1314#ifdef CONFIG_HIGHMEM 1315static void try_to_free_low(struct hstate *h, unsigned long count, 1316 nodemask_t *nodes_allowed) 1317{ 1318 int i; 1319 1320 if (h->order >= MAX_ORDER) 1321 return; 1322 1323 for_each_node_mask(i, *nodes_allowed) { 1324 struct page *page, *next; 1325 struct list_head *freel = &h->hugepage_freelists[i]; 1326 list_for_each_entry_safe(page, next, freel, lru) { 1327 if (count >= h->nr_huge_pages) 1328 return; 1329 if (PageHighMem(page)) 1330 continue; 1331 list_del(&page->lru); 1332 update_and_free_page(h, page); 1333 h->free_huge_pages--; 1334 h->free_huge_pages_node[page_to_nid(page)]--; 1335 } 1336 } 1337} 1338#else 1339static inline void try_to_free_low(struct hstate *h, unsigned long count, 1340 nodemask_t *nodes_allowed) 1341{ 1342} 1343#endif 1344 1345/* 1346 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1347 * balanced by operating on them in a round-robin fashion. 1348 * Returns 1 if an adjustment was made. 1349 */ 1350static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1351 int delta) 1352{ 1353 int start_nid, next_nid; 1354 int ret = 0; 1355 1356 VM_BUG_ON(delta != -1 && delta != 1); 1357 1358 if (delta < 0) 1359 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 1360 else 1361 start_nid = hstate_next_node_to_free(h, nodes_allowed); 1362 next_nid = start_nid; 1363 1364 do { 1365 int nid = next_nid; 1366 if (delta < 0) { 1367 /* 1368 * To shrink on this node, there must be a surplus page 1369 */ 1370 if (!h->surplus_huge_pages_node[nid]) { 1371 next_nid = hstate_next_node_to_alloc(h, 1372 nodes_allowed); 1373 continue; 1374 } 1375 } 1376 if (delta > 0) { 1377 /* 1378 * Surplus cannot exceed the total number of pages 1379 */ 1380 if (h->surplus_huge_pages_node[nid] >= 1381 h->nr_huge_pages_node[nid]) { 1382 next_nid = hstate_next_node_to_free(h, 1383 nodes_allowed); 1384 continue; 1385 } 1386 } 1387 1388 h->surplus_huge_pages += delta; 1389 h->surplus_huge_pages_node[nid] += delta; 1390 ret = 1; 1391 break; 1392 } while (next_nid != start_nid); 1393 1394 return ret; 1395} 1396 1397#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1398static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1399 nodemask_t *nodes_allowed) 1400{ 1401 unsigned long min_count, ret; 1402 1403 if (h->order >= MAX_ORDER) 1404 return h->max_huge_pages; 1405 1406 /* 1407 * Increase the pool size 1408 * First take pages out of surplus state. Then make up the 1409 * remaining difference by allocating fresh huge pages. 1410 * 1411 * We might race with alloc_buddy_huge_page() here and be unable 1412 * to convert a surplus huge page to a normal huge page. That is 1413 * not critical, though, it just means the overall size of the 1414 * pool might be one hugepage larger than it needs to be, but 1415 * within all the constraints specified by the sysctls. 1416 */ 1417 spin_lock(&hugetlb_lock); 1418 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1419 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1420 break; 1421 } 1422 1423 while (count > persistent_huge_pages(h)) { 1424 /* 1425 * If this allocation races such that we no longer need the 1426 * page, free_huge_page will handle it by freeing the page 1427 * and reducing the surplus. 1428 */ 1429 spin_unlock(&hugetlb_lock); 1430 ret = alloc_fresh_huge_page(h, nodes_allowed); 1431 spin_lock(&hugetlb_lock); 1432 if (!ret) 1433 goto out; 1434 1435 /* Bail for signals. Probably ctrl-c from user */ 1436 if (signal_pending(current)) 1437 goto out; 1438 } 1439 1440 /* 1441 * Decrease the pool size 1442 * First return free pages to the buddy allocator (being careful 1443 * to keep enough around to satisfy reservations). Then place 1444 * pages into surplus state as needed so the pool will shrink 1445 * to the desired size as pages become free. 1446 * 1447 * By placing pages into the surplus state independent of the 1448 * overcommit value, we are allowing the surplus pool size to 1449 * exceed overcommit. There are few sane options here. Since 1450 * alloc_buddy_huge_page() is checking the global counter, 1451 * though, we'll note that we're not allowed to exceed surplus 1452 * and won't grow the pool anywhere else. Not until one of the 1453 * sysctls are changed, or the surplus pages go out of use. 1454 */ 1455 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1456 min_count = max(count, min_count); 1457 try_to_free_low(h, min_count, nodes_allowed); 1458 while (min_count < persistent_huge_pages(h)) { 1459 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1460 break; 1461 } 1462 while (count < persistent_huge_pages(h)) { 1463 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1464 break; 1465 } 1466out: 1467 ret = persistent_huge_pages(h); 1468 spin_unlock(&hugetlb_lock); 1469 return ret; 1470} 1471 1472#define HSTATE_ATTR_RO(_name) \ 1473 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1474 1475#define HSTATE_ATTR(_name) \ 1476 static struct kobj_attribute _name##_attr = \ 1477 __ATTR(_name, 0644, _name##_show, _name##_store) 1478 1479static struct kobject *hugepages_kobj; 1480static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1481 1482static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1483 1484static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1485{ 1486 int i; 1487 1488 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1489 if (hstate_kobjs[i] == kobj) { 1490 if (nidp) 1491 *nidp = NUMA_NO_NODE; 1492 return &hstates[i]; 1493 } 1494 1495 return kobj_to_node_hstate(kobj, nidp); 1496} 1497 1498static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1499 struct kobj_attribute *attr, char *buf) 1500{ 1501 struct hstate *h; 1502 unsigned long nr_huge_pages; 1503 int nid; 1504 1505 h = kobj_to_hstate(kobj, &nid); 1506 if (nid == NUMA_NO_NODE) 1507 nr_huge_pages = h->nr_huge_pages; 1508 else 1509 nr_huge_pages = h->nr_huge_pages_node[nid]; 1510 1511 return sprintf(buf, "%lu\n", nr_huge_pages); 1512} 1513 1514static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1515 struct kobject *kobj, struct kobj_attribute *attr, 1516 const char *buf, size_t len) 1517{ 1518 int err; 1519 int nid; 1520 unsigned long count; 1521 struct hstate *h; 1522 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1523 1524 err = kstrtoul(buf, 10, &count); 1525 if (err) 1526 goto out; 1527 1528 h = kobj_to_hstate(kobj, &nid); 1529 if (h->order >= MAX_ORDER) { 1530 err = -EINVAL; 1531 goto out; 1532 } 1533 1534 if (nid == NUMA_NO_NODE) { 1535 /* 1536 * global hstate attribute 1537 */ 1538 if (!(obey_mempolicy && 1539 init_nodemask_of_mempolicy(nodes_allowed))) { 1540 NODEMASK_FREE(nodes_allowed); 1541 nodes_allowed = &node_states[N_MEMORY]; 1542 } 1543 } else if (nodes_allowed) { 1544 /* 1545 * per node hstate attribute: adjust count to global, 1546 * but restrict alloc/free to the specified node. 1547 */ 1548 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1549 init_nodemask_of_node(nodes_allowed, nid); 1550 } else 1551 nodes_allowed = &node_states[N_MEMORY]; 1552 1553 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1554 1555 if (nodes_allowed != &node_states[N_MEMORY]) 1556 NODEMASK_FREE(nodes_allowed); 1557 1558 return len; 1559out: 1560 NODEMASK_FREE(nodes_allowed); 1561 return err; 1562} 1563 1564static ssize_t nr_hugepages_show(struct kobject *kobj, 1565 struct kobj_attribute *attr, char *buf) 1566{ 1567 return nr_hugepages_show_common(kobj, attr, buf); 1568} 1569 1570static ssize_t nr_hugepages_store(struct kobject *kobj, 1571 struct kobj_attribute *attr, const char *buf, size_t len) 1572{ 1573 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1574} 1575HSTATE_ATTR(nr_hugepages); 1576 1577#ifdef CONFIG_NUMA 1578 1579/* 1580 * hstate attribute for optionally mempolicy-based constraint on persistent 1581 * huge page alloc/free. 1582 */ 1583static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1584 struct kobj_attribute *attr, char *buf) 1585{ 1586 return nr_hugepages_show_common(kobj, attr, buf); 1587} 1588 1589static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1590 struct kobj_attribute *attr, const char *buf, size_t len) 1591{ 1592 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1593} 1594HSTATE_ATTR(nr_hugepages_mempolicy); 1595#endif 1596 1597 1598static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1599 struct kobj_attribute *attr, char *buf) 1600{ 1601 struct hstate *h = kobj_to_hstate(kobj, NULL); 1602 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1603} 1604 1605static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1606 struct kobj_attribute *attr, const char *buf, size_t count) 1607{ 1608 int err; 1609 unsigned long input; 1610 struct hstate *h = kobj_to_hstate(kobj, NULL); 1611 1612 if (h->order >= MAX_ORDER) 1613 return -EINVAL; 1614 1615 err = kstrtoul(buf, 10, &input); 1616 if (err) 1617 return err; 1618 1619 spin_lock(&hugetlb_lock); 1620 h->nr_overcommit_huge_pages = input; 1621 spin_unlock(&hugetlb_lock); 1622 1623 return count; 1624} 1625HSTATE_ATTR(nr_overcommit_hugepages); 1626 1627static ssize_t free_hugepages_show(struct kobject *kobj, 1628 struct kobj_attribute *attr, char *buf) 1629{ 1630 struct hstate *h; 1631 unsigned long free_huge_pages; 1632 int nid; 1633 1634 h = kobj_to_hstate(kobj, &nid); 1635 if (nid == NUMA_NO_NODE) 1636 free_huge_pages = h->free_huge_pages; 1637 else 1638 free_huge_pages = h->free_huge_pages_node[nid]; 1639 1640 return sprintf(buf, "%lu\n", free_huge_pages); 1641} 1642HSTATE_ATTR_RO(free_hugepages); 1643 1644static ssize_t resv_hugepages_show(struct kobject *kobj, 1645 struct kobj_attribute *attr, char *buf) 1646{ 1647 struct hstate *h = kobj_to_hstate(kobj, NULL); 1648 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1649} 1650HSTATE_ATTR_RO(resv_hugepages); 1651 1652static ssize_t surplus_hugepages_show(struct kobject *kobj, 1653 struct kobj_attribute *attr, char *buf) 1654{ 1655 struct hstate *h; 1656 unsigned long surplus_huge_pages; 1657 int nid; 1658 1659 h = kobj_to_hstate(kobj, &nid); 1660 if (nid == NUMA_NO_NODE) 1661 surplus_huge_pages = h->surplus_huge_pages; 1662 else 1663 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1664 1665 return sprintf(buf, "%lu\n", surplus_huge_pages); 1666} 1667HSTATE_ATTR_RO(surplus_hugepages); 1668 1669static struct attribute *hstate_attrs[] = { 1670 &nr_hugepages_attr.attr, 1671 &nr_overcommit_hugepages_attr.attr, 1672 &free_hugepages_attr.attr, 1673 &resv_hugepages_attr.attr, 1674 &surplus_hugepages_attr.attr, 1675#ifdef CONFIG_NUMA 1676 &nr_hugepages_mempolicy_attr.attr, 1677#endif 1678 NULL, 1679}; 1680 1681static struct attribute_group hstate_attr_group = { 1682 .attrs = hstate_attrs, 1683}; 1684 1685static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, 1686 struct kobject **hstate_kobjs, 1687 struct attribute_group *hstate_attr_group) 1688{ 1689 int retval; 1690 int hi = hstate_index(h); 1691 1692 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1693 if (!hstate_kobjs[hi]) 1694 return -ENOMEM; 1695 1696 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1697 if (retval) 1698 kobject_put(hstate_kobjs[hi]); 1699 1700 return retval; 1701} 1702 1703static void __init hugetlb_sysfs_init(void) 1704{ 1705 struct hstate *h; 1706 int err; 1707 1708 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1709 if (!hugepages_kobj) 1710 return; 1711 1712 for_each_hstate(h) { 1713 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1714 hstate_kobjs, &hstate_attr_group); 1715 if (err) 1716 pr_err("Hugetlb: Unable to add hstate %s", h->name); 1717 } 1718} 1719 1720#ifdef CONFIG_NUMA 1721 1722/* 1723 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1724 * with node devices in node_devices[] using a parallel array. The array 1725 * index of a node device or _hstate == node id. 1726 * This is here to avoid any static dependency of the node device driver, in 1727 * the base kernel, on the hugetlb module. 1728 */ 1729struct node_hstate { 1730 struct kobject *hugepages_kobj; 1731 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1732}; 1733struct node_hstate node_hstates[MAX_NUMNODES]; 1734 1735/* 1736 * A subset of global hstate attributes for node devices 1737 */ 1738static struct attribute *per_node_hstate_attrs[] = { 1739 &nr_hugepages_attr.attr, 1740 &free_hugepages_attr.attr, 1741 &surplus_hugepages_attr.attr, 1742 NULL, 1743}; 1744 1745static struct attribute_group per_node_hstate_attr_group = { 1746 .attrs = per_node_hstate_attrs, 1747}; 1748 1749/* 1750 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. 1751 * Returns node id via non-NULL nidp. 1752 */ 1753static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1754{ 1755 int nid; 1756 1757 for (nid = 0; nid < nr_node_ids; nid++) { 1758 struct node_hstate *nhs = &node_hstates[nid]; 1759 int i; 1760 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1761 if (nhs->hstate_kobjs[i] == kobj) { 1762 if (nidp) 1763 *nidp = nid; 1764 return &hstates[i]; 1765 } 1766 } 1767 1768 BUG(); 1769 return NULL; 1770} 1771 1772/* 1773 * Unregister hstate attributes from a single node device. 1774 * No-op if no hstate attributes attached. 1775 */ 1776static void hugetlb_unregister_node(struct node *node) 1777{ 1778 struct hstate *h; 1779 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1780 1781 if (!nhs->hugepages_kobj) 1782 return; /* no hstate attributes */ 1783 1784 for_each_hstate(h) { 1785 int idx = hstate_index(h); 1786 if (nhs->hstate_kobjs[idx]) { 1787 kobject_put(nhs->hstate_kobjs[idx]); 1788 nhs->hstate_kobjs[idx] = NULL; 1789 } 1790 } 1791 1792 kobject_put(nhs->hugepages_kobj); 1793 nhs->hugepages_kobj = NULL; 1794} 1795 1796/* 1797 * hugetlb module exit: unregister hstate attributes from node devices 1798 * that have them. 1799 */ 1800static void hugetlb_unregister_all_nodes(void) 1801{ 1802 int nid; 1803 1804 /* 1805 * disable node device registrations. 1806 */ 1807 register_hugetlbfs_with_node(NULL, NULL); 1808 1809 /* 1810 * remove hstate attributes from any nodes that have them. 1811 */ 1812 for (nid = 0; nid < nr_node_ids; nid++) 1813 hugetlb_unregister_node(node_devices[nid]); 1814} 1815 1816/* 1817 * Register hstate attributes for a single node device. 1818 * No-op if attributes already registered. 1819 */ 1820static void hugetlb_register_node(struct node *node) 1821{ 1822 struct hstate *h; 1823 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1824 int err; 1825 1826 if (nhs->hugepages_kobj) 1827 return; /* already allocated */ 1828 1829 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1830 &node->dev.kobj); 1831 if (!nhs->hugepages_kobj) 1832 return; 1833 1834 for_each_hstate(h) { 1835 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1836 nhs->hstate_kobjs, 1837 &per_node_hstate_attr_group); 1838 if (err) { 1839 pr_err("Hugetlb: Unable to add hstate %s for node %d\n", 1840 h->name, node->dev.id); 1841 hugetlb_unregister_node(node); 1842 break; 1843 } 1844 } 1845} 1846 1847/* 1848 * hugetlb init time: register hstate attributes for all registered node 1849 * devices of nodes that have memory. All on-line nodes should have 1850 * registered their associated device by this time. 1851 */ 1852static void hugetlb_register_all_nodes(void) 1853{ 1854 int nid; 1855 1856 for_each_node_state(nid, N_MEMORY) { 1857 struct node *node = node_devices[nid]; 1858 if (node->dev.id == nid) 1859 hugetlb_register_node(node); 1860 } 1861 1862 /* 1863 * Let the node device driver know we're here so it can 1864 * [un]register hstate attributes on node hotplug. 1865 */ 1866 register_hugetlbfs_with_node(hugetlb_register_node, 1867 hugetlb_unregister_node); 1868} 1869#else /* !CONFIG_NUMA */ 1870 1871static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1872{ 1873 BUG(); 1874 if (nidp) 1875 *nidp = -1; 1876 return NULL; 1877} 1878 1879static void hugetlb_unregister_all_nodes(void) { } 1880 1881static void hugetlb_register_all_nodes(void) { } 1882 1883#endif 1884 1885static void __exit hugetlb_exit(void) 1886{ 1887 struct hstate *h; 1888 1889 hugetlb_unregister_all_nodes(); 1890 1891 for_each_hstate(h) { 1892 kobject_put(hstate_kobjs[hstate_index(h)]); 1893 } 1894 1895 kobject_put(hugepages_kobj); 1896} 1897module_exit(hugetlb_exit); 1898 1899static int __init hugetlb_init(void) 1900{ 1901 /* Some platform decide whether they support huge pages at boot 1902 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1903 * there is no such support 1904 */ 1905 if (HPAGE_SHIFT == 0) 1906 return 0; 1907 1908 if (!size_to_hstate(default_hstate_size)) { 1909 default_hstate_size = HPAGE_SIZE; 1910 if (!size_to_hstate(default_hstate_size)) 1911 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1912 } 1913 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); 1914 if (default_hstate_max_huge_pages) 1915 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1916 1917 hugetlb_init_hstates(); 1918 gather_bootmem_prealloc(); 1919 report_hugepages(); 1920 1921 hugetlb_sysfs_init(); 1922 hugetlb_register_all_nodes(); 1923 hugetlb_cgroup_file_init(); 1924 1925 return 0; 1926} 1927module_init(hugetlb_init); 1928 1929/* Should be called on processing a hugepagesz=... option */ 1930void __init hugetlb_add_hstate(unsigned order) 1931{ 1932 struct hstate *h; 1933 unsigned long i; 1934 1935 if (size_to_hstate(PAGE_SIZE << order)) { 1936 pr_warning("hugepagesz= specified twice, ignoring\n"); 1937 return; 1938 } 1939 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); 1940 BUG_ON(order == 0); 1941 h = &hstates[hugetlb_max_hstate++]; 1942 h->order = order; 1943 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1944 h->nr_huge_pages = 0; 1945 h->free_huge_pages = 0; 1946 for (i = 0; i < MAX_NUMNODES; ++i) 1947 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1948 INIT_LIST_HEAD(&h->hugepage_activelist); 1949 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); 1950 h->next_nid_to_free = first_node(node_states[N_MEMORY]); 1951 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1952 huge_page_size(h)/1024); 1953 1954 parsed_hstate = h; 1955} 1956 1957static int __init hugetlb_nrpages_setup(char *s) 1958{ 1959 unsigned long *mhp; 1960 static unsigned long *last_mhp; 1961 1962 /* 1963 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, 1964 * so this hugepages= parameter goes to the "default hstate". 1965 */ 1966 if (!hugetlb_max_hstate) 1967 mhp = &default_hstate_max_huge_pages; 1968 else 1969 mhp = &parsed_hstate->max_huge_pages; 1970 1971 if (mhp == last_mhp) { 1972 pr_warning("hugepages= specified twice without " 1973 "interleaving hugepagesz=, ignoring\n"); 1974 return 1; 1975 } 1976 1977 if (sscanf(s, "%lu", mhp) <= 0) 1978 *mhp = 0; 1979 1980 /* 1981 * Global state is always initialized later in hugetlb_init. 1982 * But we need to allocate >= MAX_ORDER hstates here early to still 1983 * use the bootmem allocator. 1984 */ 1985 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) 1986 hugetlb_hstate_alloc_pages(parsed_hstate); 1987 1988 last_mhp = mhp; 1989 1990 return 1; 1991} 1992__setup("hugepages=", hugetlb_nrpages_setup); 1993 1994static int __init hugetlb_default_setup(char *s) 1995{ 1996 default_hstate_size = memparse(s, &s); 1997 return 1; 1998} 1999__setup("default_hugepagesz=", hugetlb_default_setup); 2000 2001static unsigned int cpuset_mems_nr(unsigned int *array) 2002{ 2003 int node; 2004 unsigned int nr = 0; 2005 2006 for_each_node_mask(node, cpuset_current_mems_allowed) 2007 nr += array[node]; 2008 2009 return nr; 2010} 2011 2012#ifdef CONFIG_SYSCTL 2013static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 2014 struct ctl_table *table, int write, 2015 void __user *buffer, size_t *length, loff_t *ppos) 2016{ 2017 struct hstate *h = &default_hstate; 2018 unsigned long tmp; 2019 int ret; 2020 2021 tmp = h->max_huge_pages; 2022 2023 if (write && h->order >= MAX_ORDER) 2024 return -EINVAL; 2025 2026 table->data = &tmp; 2027 table->maxlen = sizeof(unsigned long); 2028 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2029 if (ret) 2030 goto out; 2031 2032 if (write) { 2033 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 2034 GFP_KERNEL | __GFP_NORETRY); 2035 if (!(obey_mempolicy && 2036 init_nodemask_of_mempolicy(nodes_allowed))) { 2037 NODEMASK_FREE(nodes_allowed); 2038 nodes_allowed = &node_states[N_MEMORY]; 2039 } 2040 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 2041 2042 if (nodes_allowed != &node_states[N_MEMORY]) 2043 NODEMASK_FREE(nodes_allowed); 2044 } 2045out: 2046 return ret; 2047} 2048 2049int hugetlb_sysctl_handler(struct ctl_table *table, int write, 2050 void __user *buffer, size_t *length, loff_t *ppos) 2051{ 2052 2053 return hugetlb_sysctl_handler_common(false, table, write, 2054 buffer, length, ppos); 2055} 2056 2057#ifdef CONFIG_NUMA 2058int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 2059 void __user *buffer, size_t *length, loff_t *ppos) 2060{ 2061 return hugetlb_sysctl_handler_common(true, table, write, 2062 buffer, length, ppos); 2063} 2064#endif /* CONFIG_NUMA */ 2065 2066int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 2067 void __user *buffer, 2068 size_t *length, loff_t *ppos) 2069{ 2070 proc_dointvec(table, write, buffer, length, ppos); 2071 if (hugepages_treat_as_movable) 2072 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 2073 else 2074 htlb_alloc_mask = GFP_HIGHUSER; 2075 return 0; 2076} 2077 2078int hugetlb_overcommit_handler(struct ctl_table *table, int write, 2079 void __user *buffer, 2080 size_t *length, loff_t *ppos) 2081{ 2082 struct hstate *h = &default_hstate; 2083 unsigned long tmp; 2084 int ret; 2085 2086 tmp = h->nr_overcommit_huge_pages; 2087 2088 if (write && h->order >= MAX_ORDER) 2089 return -EINVAL; 2090 2091 table->data = &tmp; 2092 table->maxlen = sizeof(unsigned long); 2093 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2094 if (ret) 2095 goto out; 2096 2097 if (write) { 2098 spin_lock(&hugetlb_lock); 2099 h->nr_overcommit_huge_pages = tmp; 2100 spin_unlock(&hugetlb_lock); 2101 } 2102out: 2103 return ret; 2104} 2105 2106#endif /* CONFIG_SYSCTL */ 2107 2108void hugetlb_report_meminfo(struct seq_file *m) 2109{ 2110 struct hstate *h = &default_hstate; 2111 seq_printf(m, 2112 "HugePages_Total: %5lu\n" 2113 "HugePages_Free: %5lu\n" 2114 "HugePages_Rsvd: %5lu\n" 2115 "HugePages_Surp: %5lu\n" 2116 "Hugepagesize: %8lu kB\n", 2117 h->nr_huge_pages, 2118 h->free_huge_pages, 2119 h->resv_huge_pages, 2120 h->surplus_huge_pages, 2121 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2122} 2123 2124int hugetlb_report_node_meminfo(int nid, char *buf) 2125{ 2126 struct hstate *h = &default_hstate; 2127 return sprintf(buf, 2128 "Node %d HugePages_Total: %5u\n" 2129 "Node %d HugePages_Free: %5u\n" 2130 "Node %d HugePages_Surp: %5u\n", 2131 nid, h->nr_huge_pages_node[nid], 2132 nid, h->free_huge_pages_node[nid], 2133 nid, h->surplus_huge_pages_node[nid]); 2134} 2135 2136void hugetlb_show_meminfo(void) 2137{ 2138 struct hstate *h; 2139 int nid; 2140 2141 for_each_node_state(nid, N_MEMORY) 2142 for_each_hstate(h) 2143 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", 2144 nid, 2145 h->nr_huge_pages_node[nid], 2146 h->free_huge_pages_node[nid], 2147 h->surplus_huge_pages_node[nid], 2148 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2149} 2150 2151/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 2152unsigned long hugetlb_total_pages(void) 2153{ 2154 struct hstate *h; 2155 unsigned long nr_total_pages = 0; 2156 2157 for_each_hstate(h) 2158 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); 2159 return nr_total_pages; 2160} 2161 2162static int hugetlb_acct_memory(struct hstate *h, long delta) 2163{ 2164 int ret = -ENOMEM; 2165 2166 spin_lock(&hugetlb_lock); 2167 /* 2168 * When cpuset is configured, it breaks the strict hugetlb page 2169 * reservation as the accounting is done on a global variable. Such 2170 * reservation is completely rubbish in the presence of cpuset because 2171 * the reservation is not checked against page availability for the 2172 * current cpuset. Application can still potentially OOM'ed by kernel 2173 * with lack of free htlb page in cpuset that the task is in. 2174 * Attempt to enforce strict accounting with cpuset is almost 2175 * impossible (or too ugly) because cpuset is too fluid that 2176 * task or memory node can be dynamically moved between cpusets. 2177 * 2178 * The change of semantics for shared hugetlb mapping with cpuset is 2179 * undesirable. However, in order to preserve some of the semantics, 2180 * we fall back to check against current free page availability as 2181 * a best attempt and hopefully to minimize the impact of changing 2182 * semantics that cpuset has. 2183 */ 2184 if (delta > 0) { 2185 if (gather_surplus_pages(h, delta) < 0) 2186 goto out; 2187 2188 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 2189 return_unused_surplus_pages(h, delta); 2190 goto out; 2191 } 2192 } 2193 2194 ret = 0; 2195 if (delta < 0) 2196 return_unused_surplus_pages(h, (unsigned long) -delta); 2197 2198out: 2199 spin_unlock(&hugetlb_lock); 2200 return ret; 2201} 2202 2203static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2204{ 2205 struct resv_map *reservations = vma_resv_map(vma); 2206 2207 /* 2208 * This new VMA should share its siblings reservation map if present. 2209 * The VMA will only ever have a valid reservation map pointer where 2210 * it is being copied for another still existing VMA. As that VMA 2211 * has a reference to the reservation map it cannot disappear until 2212 * after this open call completes. It is therefore safe to take a 2213 * new reference here without additional locking. 2214 */ 2215 if (reservations) 2216 kref_get(&reservations->refs); 2217} 2218 2219static void resv_map_put(struct vm_area_struct *vma) 2220{ 2221 struct resv_map *reservations = vma_resv_map(vma); 2222 2223 if (!reservations) 2224 return; 2225 kref_put(&reservations->refs, resv_map_release); 2226} 2227 2228static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2229{ 2230 struct hstate *h = hstate_vma(vma); 2231 struct resv_map *reservations = vma_resv_map(vma); 2232 struct hugepage_subpool *spool = subpool_vma(vma); 2233 unsigned long reserve; 2234 unsigned long start; 2235 unsigned long end; 2236 2237 if (reservations) { 2238 start = vma_hugecache_offset(h, vma, vma->vm_start); 2239 end = vma_hugecache_offset(h, vma, vma->vm_end); 2240 2241 reserve = (end - start) - 2242 region_count(&reservations->regions, start, end); 2243 2244 resv_map_put(vma); 2245 2246 if (reserve) { 2247 hugetlb_acct_memory(h, -reserve); 2248 hugepage_subpool_put_pages(spool, reserve); 2249 } 2250 } 2251} 2252 2253/* 2254 * We cannot handle pagefaults against hugetlb pages at all. They cause 2255 * handle_mm_fault() to try to instantiate regular-sized pages in the 2256 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2257 * this far. 2258 */ 2259static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2260{ 2261 BUG(); 2262 return 0; 2263} 2264 2265const struct vm_operations_struct hugetlb_vm_ops = { 2266 .fault = hugetlb_vm_op_fault, 2267 .open = hugetlb_vm_op_open, 2268 .close = hugetlb_vm_op_close, 2269}; 2270 2271static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2272 int writable) 2273{ 2274 pte_t entry; 2275 2276 if (writable) { 2277 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, 2278 vma->vm_page_prot))); 2279 } else { 2280 entry = huge_pte_wrprotect(mk_huge_pte(page, 2281 vma->vm_page_prot)); 2282 } 2283 entry = pte_mkyoung(entry); 2284 entry = pte_mkhuge(entry); 2285 entry = arch_make_huge_pte(entry, vma, page, writable); 2286 2287 return entry; 2288} 2289 2290static void set_huge_ptep_writable(struct vm_area_struct *vma, 2291 unsigned long address, pte_t *ptep) 2292{ 2293 pte_t entry; 2294 2295 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); 2296 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) 2297 update_mmu_cache(vma, address, ptep); 2298} 2299 2300 2301int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2302 struct vm_area_struct *vma) 2303{ 2304 pte_t *src_pte, *dst_pte, entry; 2305 struct page *ptepage; 2306 unsigned long addr; 2307 int cow; 2308 struct hstate *h = hstate_vma(vma); 2309 unsigned long sz = huge_page_size(h); 2310 2311 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2312 2313 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2314 src_pte = huge_pte_offset(src, addr); 2315 if (!src_pte) 2316 continue; 2317 dst_pte = huge_pte_alloc(dst, addr, sz); 2318 if (!dst_pte) 2319 goto nomem; 2320 2321 /* If the pagetables are shared don't copy or take references */ 2322 if (dst_pte == src_pte) 2323 continue; 2324 2325 spin_lock(&dst->page_table_lock); 2326 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 2327 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2328 if (cow) 2329 huge_ptep_set_wrprotect(src, addr, src_pte); 2330 entry = huge_ptep_get(src_pte); 2331 ptepage = pte_page(entry); 2332 get_page(ptepage); 2333 page_dup_rmap(ptepage); 2334 set_huge_pte_at(dst, addr, dst_pte, entry); 2335 } 2336 spin_unlock(&src->page_table_lock); 2337 spin_unlock(&dst->page_table_lock); 2338 } 2339 return 0; 2340 2341nomem: 2342 return -ENOMEM; 2343} 2344 2345static int is_hugetlb_entry_migration(pte_t pte) 2346{ 2347 swp_entry_t swp; 2348 2349 if (huge_pte_none(pte) || pte_present(pte)) 2350 return 0; 2351 swp = pte_to_swp_entry(pte); 2352 if (non_swap_entry(swp) && is_migration_entry(swp)) 2353 return 1; 2354 else 2355 return 0; 2356} 2357 2358static int is_hugetlb_entry_hwpoisoned(pte_t pte) 2359{ 2360 swp_entry_t swp; 2361 2362 if (huge_pte_none(pte) || pte_present(pte)) 2363 return 0; 2364 swp = pte_to_swp_entry(pte); 2365 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) 2366 return 1; 2367 else 2368 return 0; 2369} 2370 2371void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 2372 unsigned long start, unsigned long end, 2373 struct page *ref_page) 2374{ 2375 int force_flush = 0; 2376 struct mm_struct *mm = vma->vm_mm; 2377 unsigned long address; 2378 pte_t *ptep; 2379 pte_t pte; 2380 struct page *page; 2381 struct hstate *h = hstate_vma(vma); 2382 unsigned long sz = huge_page_size(h); 2383 const unsigned long mmun_start = start; /* For mmu_notifiers */ 2384 const unsigned long mmun_end = end; /* For mmu_notifiers */ 2385 2386 WARN_ON(!is_vm_hugetlb_page(vma)); 2387 BUG_ON(start & ~huge_page_mask(h)); 2388 BUG_ON(end & ~huge_page_mask(h)); 2389 2390 tlb_start_vma(tlb, vma); 2391 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2392again: 2393 spin_lock(&mm->page_table_lock); 2394 for (address = start; address < end; address += sz) { 2395 ptep = huge_pte_offset(mm, address); 2396 if (!ptep) 2397 continue; 2398 2399 if (huge_pmd_unshare(mm, &address, ptep)) 2400 continue; 2401 2402 pte = huge_ptep_get(ptep); 2403 if (huge_pte_none(pte)) 2404 continue; 2405 2406 /* 2407 * HWPoisoned hugepage is already unmapped and dropped reference 2408 */ 2409 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { 2410 huge_pte_clear(mm, address, ptep); 2411 continue; 2412 } 2413 2414 page = pte_page(pte); 2415 /* 2416 * If a reference page is supplied, it is because a specific 2417 * page is being unmapped, not a range. Ensure the page we 2418 * are about to unmap is the actual page of interest. 2419 */ 2420 if (ref_page) { 2421 if (page != ref_page) 2422 continue; 2423 2424 /* 2425 * Mark the VMA as having unmapped its page so that 2426 * future faults in this VMA will fail rather than 2427 * looking like data was lost 2428 */ 2429 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2430 } 2431 2432 pte = huge_ptep_get_and_clear(mm, address, ptep); 2433 tlb_remove_tlb_entry(tlb, ptep, address); 2434 if (huge_pte_dirty(pte)) 2435 set_page_dirty(page); 2436 2437 page_remove_rmap(page); 2438 force_flush = !__tlb_remove_page(tlb, page); 2439 if (force_flush) 2440 break; 2441 /* Bail out after unmapping reference page if supplied */ 2442 if (ref_page) 2443 break; 2444 } 2445 spin_unlock(&mm->page_table_lock); 2446 /* 2447 * mmu_gather ran out of room to batch pages, we break out of 2448 * the PTE lock to avoid doing the potential expensive TLB invalidate 2449 * and page-free while holding it. 2450 */ 2451 if (force_flush) { 2452 force_flush = 0; 2453 tlb_flush_mmu(tlb); 2454 if (address < end && !ref_page) 2455 goto again; 2456 } 2457 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2458 tlb_end_vma(tlb, vma); 2459} 2460 2461void __unmap_hugepage_range_final(struct mmu_gather *tlb, 2462 struct vm_area_struct *vma, unsigned long start, 2463 unsigned long end, struct page *ref_page) 2464{ 2465 __unmap_hugepage_range(tlb, vma, start, end, ref_page); 2466 2467 /* 2468 * Clear this flag so that x86's huge_pmd_share page_table_shareable 2469 * test will fail on a vma being torn down, and not grab a page table 2470 * on its way out. We're lucky that the flag has such an appropriate 2471 * name, and can in fact be safely cleared here. We could clear it 2472 * before the __unmap_hugepage_range above, but all that's necessary 2473 * is to clear it before releasing the i_mmap_mutex. This works 2474 * because in the context this is called, the VMA is about to be 2475 * destroyed and the i_mmap_mutex is held. 2476 */ 2477 vma->vm_flags &= ~VM_MAYSHARE; 2478} 2479 2480void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2481 unsigned long end, struct page *ref_page) 2482{ 2483 struct mm_struct *mm; 2484 struct mmu_gather tlb; 2485 2486 mm = vma->vm_mm; 2487 2488 tlb_gather_mmu(&tlb, mm, start, end); 2489 __unmap_hugepage_range(&tlb, vma, start, end, ref_page); 2490 tlb_finish_mmu(&tlb, start, end); 2491} 2492 2493/* 2494 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2495 * mappping it owns the reserve page for. The intention is to unmap the page 2496 * from other VMAs and let the children be SIGKILLed if they are faulting the 2497 * same region. 2498 */ 2499static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2500 struct page *page, unsigned long address) 2501{ 2502 struct hstate *h = hstate_vma(vma); 2503 struct vm_area_struct *iter_vma; 2504 struct address_space *mapping; 2505 pgoff_t pgoff; 2506 2507 /* 2508 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2509 * from page cache lookup which is in HPAGE_SIZE units. 2510 */ 2511 address = address & huge_page_mask(h); 2512 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + 2513 vma->vm_pgoff; 2514 mapping = file_inode(vma->vm_file)->i_mapping; 2515 2516 /* 2517 * Take the mapping lock for the duration of the table walk. As 2518 * this mapping should be shared between all the VMAs, 2519 * __unmap_hugepage_range() is called as the lock is already held 2520 */ 2521 mutex_lock(&mapping->i_mmap_mutex); 2522 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { 2523 /* Do not unmap the current VMA */ 2524 if (iter_vma == vma) 2525 continue; 2526 2527 /* 2528 * Unmap the page from other VMAs without their own reserves. 2529 * They get marked to be SIGKILLed if they fault in these 2530 * areas. This is because a future no-page fault on this VMA 2531 * could insert a zeroed page instead of the data existing 2532 * from the time of fork. This would look like data corruption 2533 */ 2534 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2535 unmap_hugepage_range(iter_vma, address, 2536 address + huge_page_size(h), page); 2537 } 2538 mutex_unlock(&mapping->i_mmap_mutex); 2539 2540 return 1; 2541} 2542 2543/* 2544 * Hugetlb_cow() should be called with page lock of the original hugepage held. 2545 * Called with hugetlb_instantiation_mutex held and pte_page locked so we 2546 * cannot race with other handlers or page migration. 2547 * Keep the pte_same checks anyway to make transition from the mutex easier. 2548 */ 2549static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2550 unsigned long address, pte_t *ptep, pte_t pte, 2551 struct page *pagecache_page) 2552{ 2553 struct hstate *h = hstate_vma(vma); 2554 struct page *old_page, *new_page; 2555 int avoidcopy; 2556 int outside_reserve = 0; 2557 unsigned long mmun_start; /* For mmu_notifiers */ 2558 unsigned long mmun_end; /* For mmu_notifiers */ 2559 2560 old_page = pte_page(pte); 2561 2562retry_avoidcopy: 2563 /* If no-one else is actually using this page, avoid the copy 2564 * and just make the page writable */ 2565 avoidcopy = (page_mapcount(old_page) == 1); 2566 if (avoidcopy) { 2567 if (PageAnon(old_page)) 2568 page_move_anon_rmap(old_page, vma, address); 2569 set_huge_ptep_writable(vma, address, ptep); 2570 return 0; 2571 } 2572 2573 /* 2574 * If the process that created a MAP_PRIVATE mapping is about to 2575 * perform a COW due to a shared page count, attempt to satisfy 2576 * the allocation without using the existing reserves. The pagecache 2577 * page is used to determine if the reserve at this address was 2578 * consumed or not. If reserves were used, a partial faulted mapping 2579 * at the time of fork() could consume its reserves on COW instead 2580 * of the full address range. 2581 */ 2582 if (!(vma->vm_flags & VM_MAYSHARE) && 2583 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2584 old_page != pagecache_page) 2585 outside_reserve = 1; 2586 2587 page_cache_get(old_page); 2588 2589 /* Drop page_table_lock as buddy allocator may be called */ 2590 spin_unlock(&mm->page_table_lock); 2591 new_page = alloc_huge_page(vma, address, outside_reserve); 2592 2593 if (IS_ERR(new_page)) { 2594 long err = PTR_ERR(new_page); 2595 page_cache_release(old_page); 2596 2597 /* 2598 * If a process owning a MAP_PRIVATE mapping fails to COW, 2599 * it is due to references held by a child and an insufficient 2600 * huge page pool. To guarantee the original mappers 2601 * reliability, unmap the page from child processes. The child 2602 * may get SIGKILLed if it later faults. 2603 */ 2604 if (outside_reserve) { 2605 BUG_ON(huge_pte_none(pte)); 2606 if (unmap_ref_private(mm, vma, old_page, address)) { 2607 BUG_ON(huge_pte_none(pte)); 2608 spin_lock(&mm->page_table_lock); 2609 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2610 if (likely(pte_same(huge_ptep_get(ptep), pte))) 2611 goto retry_avoidcopy; 2612 /* 2613 * race occurs while re-acquiring page_table_lock, and 2614 * our job is done. 2615 */ 2616 return 0; 2617 } 2618 WARN_ON_ONCE(1); 2619 } 2620 2621 /* Caller expects lock to be held */ 2622 spin_lock(&mm->page_table_lock); 2623 if (err == -ENOMEM) 2624 return VM_FAULT_OOM; 2625 else 2626 return VM_FAULT_SIGBUS; 2627 } 2628 2629 /* 2630 * When the original hugepage is shared one, it does not have 2631 * anon_vma prepared. 2632 */ 2633 if (unlikely(anon_vma_prepare(vma))) { 2634 page_cache_release(new_page); 2635 page_cache_release(old_page); 2636 /* Caller expects lock to be held */ 2637 spin_lock(&mm->page_table_lock); 2638 return VM_FAULT_OOM; 2639 } 2640 2641 copy_user_huge_page(new_page, old_page, address, vma, 2642 pages_per_huge_page(h)); 2643 __SetPageUptodate(new_page); 2644 2645 mmun_start = address & huge_page_mask(h); 2646 mmun_end = mmun_start + huge_page_size(h); 2647 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2648 /* 2649 * Retake the page_table_lock to check for racing updates 2650 * before the page tables are altered 2651 */ 2652 spin_lock(&mm->page_table_lock); 2653 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2654 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2655 /* Break COW */ 2656 huge_ptep_clear_flush(vma, address, ptep); 2657 set_huge_pte_at(mm, address, ptep, 2658 make_huge_pte(vma, new_page, 1)); 2659 page_remove_rmap(old_page); 2660 hugepage_add_new_anon_rmap(new_page, vma, address); 2661 /* Make the old page be freed below */ 2662 new_page = old_page; 2663 } 2664 spin_unlock(&mm->page_table_lock); 2665 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2666 /* Caller expects lock to be held */ 2667 spin_lock(&mm->page_table_lock); 2668 page_cache_release(new_page); 2669 page_cache_release(old_page); 2670 return 0; 2671} 2672 2673/* Return the pagecache page at a given address within a VMA */ 2674static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2675 struct vm_area_struct *vma, unsigned long address) 2676{ 2677 struct address_space *mapping; 2678 pgoff_t idx; 2679 2680 mapping = vma->vm_file->f_mapping; 2681 idx = vma_hugecache_offset(h, vma, address); 2682 2683 return find_lock_page(mapping, idx); 2684} 2685 2686/* 2687 * Return whether there is a pagecache page to back given address within VMA. 2688 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2689 */ 2690static bool hugetlbfs_pagecache_present(struct hstate *h, 2691 struct vm_area_struct *vma, unsigned long address) 2692{ 2693 struct address_space *mapping; 2694 pgoff_t idx; 2695 struct page *page; 2696 2697 mapping = vma->vm_file->f_mapping; 2698 idx = vma_hugecache_offset(h, vma, address); 2699 2700 page = find_get_page(mapping, idx); 2701 if (page) 2702 put_page(page); 2703 return page != NULL; 2704} 2705 2706static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2707 unsigned long address, pte_t *ptep, unsigned int flags) 2708{ 2709 struct hstate *h = hstate_vma(vma); 2710 int ret = VM_FAULT_SIGBUS; 2711 int anon_rmap = 0; 2712 pgoff_t idx; 2713 unsigned long size; 2714 struct page *page; 2715 struct address_space *mapping; 2716 pte_t new_pte; 2717 2718 /* 2719 * Currently, we are forced to kill the process in the event the 2720 * original mapper has unmapped pages from the child due to a failed 2721 * COW. Warn that such a situation has occurred as it may not be obvious 2722 */ 2723 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2724 pr_warning("PID %d killed due to inadequate hugepage pool\n", 2725 current->pid); 2726 return ret; 2727 } 2728 2729 mapping = vma->vm_file->f_mapping; 2730 idx = vma_hugecache_offset(h, vma, address); 2731 2732 /* 2733 * Use page lock to guard against racing truncation 2734 * before we get page_table_lock. 2735 */ 2736retry: 2737 page = find_lock_page(mapping, idx); 2738 if (!page) { 2739 size = i_size_read(mapping->host) >> huge_page_shift(h); 2740 if (idx >= size) 2741 goto out; 2742 page = alloc_huge_page(vma, address, 0); 2743 if (IS_ERR(page)) { 2744 ret = PTR_ERR(page); 2745 if (ret == -ENOMEM) 2746 ret = VM_FAULT_OOM; 2747 else 2748 ret = VM_FAULT_SIGBUS; 2749 goto out; 2750 } 2751 clear_huge_page(page, address, pages_per_huge_page(h)); 2752 __SetPageUptodate(page); 2753 2754 if (vma->vm_flags & VM_MAYSHARE) { 2755 int err; 2756 struct inode *inode = mapping->host; 2757 2758 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2759 if (err) { 2760 put_page(page); 2761 if (err == -EEXIST) 2762 goto retry; 2763 goto out; 2764 } 2765 2766 spin_lock(&inode->i_lock); 2767 inode->i_blocks += blocks_per_huge_page(h); 2768 spin_unlock(&inode->i_lock); 2769 } else { 2770 lock_page(page); 2771 if (unlikely(anon_vma_prepare(vma))) { 2772 ret = VM_FAULT_OOM; 2773 goto backout_unlocked; 2774 } 2775 anon_rmap = 1; 2776 } 2777 } else { 2778 /* 2779 * If memory error occurs between mmap() and fault, some process 2780 * don't have hwpoisoned swap entry for errored virtual address. 2781 * So we need to block hugepage fault by PG_hwpoison bit check. 2782 */ 2783 if (unlikely(PageHWPoison(page))) { 2784 ret = VM_FAULT_HWPOISON | 2785 VM_FAULT_SET_HINDEX(hstate_index(h)); 2786 goto backout_unlocked; 2787 } 2788 } 2789 2790 /* 2791 * If we are going to COW a private mapping later, we examine the 2792 * pending reservations for this page now. This will ensure that 2793 * any allocations necessary to record that reservation occur outside 2794 * the spinlock. 2795 */ 2796 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2797 if (vma_needs_reservation(h, vma, address) < 0) { 2798 ret = VM_FAULT_OOM; 2799 goto backout_unlocked; 2800 } 2801 2802 spin_lock(&mm->page_table_lock); 2803 size = i_size_read(mapping->host) >> huge_page_shift(h); 2804 if (idx >= size) 2805 goto backout; 2806 2807 ret = 0; 2808 if (!huge_pte_none(huge_ptep_get(ptep))) 2809 goto backout; 2810 2811 if (anon_rmap) 2812 hugepage_add_new_anon_rmap(page, vma, address); 2813 else 2814 page_dup_rmap(page); 2815 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2816 && (vma->vm_flags & VM_SHARED))); 2817 set_huge_pte_at(mm, address, ptep, new_pte); 2818 2819 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2820 /* Optimization, do the COW without a second fault */ 2821 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2822 } 2823 2824 spin_unlock(&mm->page_table_lock); 2825 unlock_page(page); 2826out: 2827 return ret; 2828 2829backout: 2830 spin_unlock(&mm->page_table_lock); 2831backout_unlocked: 2832 unlock_page(page); 2833 put_page(page); 2834 goto out; 2835} 2836 2837int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2838 unsigned long address, unsigned int flags) 2839{ 2840 pte_t *ptep; 2841 pte_t entry; 2842 int ret; 2843 struct page *page = NULL; 2844 struct page *pagecache_page = NULL; 2845 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2846 struct hstate *h = hstate_vma(vma); 2847 2848 address &= huge_page_mask(h); 2849 2850 ptep = huge_pte_offset(mm, address); 2851 if (ptep) { 2852 entry = huge_ptep_get(ptep); 2853 if (unlikely(is_hugetlb_entry_migration(entry))) { 2854 migration_entry_wait_huge(mm, ptep); 2855 return 0; 2856 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) 2857 return VM_FAULT_HWPOISON_LARGE | 2858 VM_FAULT_SET_HINDEX(hstate_index(h)); 2859 } 2860 2861 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2862 if (!ptep) 2863 return VM_FAULT_OOM; 2864 2865 /* 2866 * Serialize hugepage allocation and instantiation, so that we don't 2867 * get spurious allocation failures if two CPUs race to instantiate 2868 * the same page in the page cache. 2869 */ 2870 mutex_lock(&hugetlb_instantiation_mutex); 2871 entry = huge_ptep_get(ptep); 2872 if (huge_pte_none(entry)) { 2873 ret = hugetlb_no_page(mm, vma, address, ptep, flags); 2874 goto out_mutex; 2875 } 2876 2877 ret = 0; 2878 2879 /* 2880 * If we are going to COW the mapping later, we examine the pending 2881 * reservations for this page now. This will ensure that any 2882 * allocations necessary to record that reservation occur outside the 2883 * spinlock. For private mappings, we also lookup the pagecache 2884 * page now as it is used to determine if a reservation has been 2885 * consumed. 2886 */ 2887 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { 2888 if (vma_needs_reservation(h, vma, address) < 0) { 2889 ret = VM_FAULT_OOM; 2890 goto out_mutex; 2891 } 2892 2893 if (!(vma->vm_flags & VM_MAYSHARE)) 2894 pagecache_page = hugetlbfs_pagecache_page(h, 2895 vma, address); 2896 } 2897 2898 /* 2899 * hugetlb_cow() requires page locks of pte_page(entry) and 2900 * pagecache_page, so here we need take the former one 2901 * when page != pagecache_page or !pagecache_page. 2902 * Note that locking order is always pagecache_page -> page, 2903 * so no worry about deadlock. 2904 */ 2905 page = pte_page(entry); 2906 get_page(page); 2907 if (page != pagecache_page) 2908 lock_page(page); 2909 2910 spin_lock(&mm->page_table_lock); 2911 /* Check for a racing update before calling hugetlb_cow */ 2912 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2913 goto out_page_table_lock; 2914 2915 2916 if (flags & FAULT_FLAG_WRITE) { 2917 if (!huge_pte_write(entry)) { 2918 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2919 pagecache_page); 2920 goto out_page_table_lock; 2921 } 2922 entry = huge_pte_mkdirty(entry); 2923 } 2924 entry = pte_mkyoung(entry); 2925 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 2926 flags & FAULT_FLAG_WRITE)) 2927 update_mmu_cache(vma, address, ptep); 2928 2929out_page_table_lock: 2930 spin_unlock(&mm->page_table_lock); 2931 2932 if (pagecache_page) { 2933 unlock_page(pagecache_page); 2934 put_page(pagecache_page); 2935 } 2936 if (page != pagecache_page) 2937 unlock_page(page); 2938 put_page(page); 2939 2940out_mutex: 2941 mutex_unlock(&hugetlb_instantiation_mutex); 2942 2943 return ret; 2944} 2945 2946long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2947 struct page **pages, struct vm_area_struct **vmas, 2948 unsigned long *position, unsigned long *nr_pages, 2949 long i, unsigned int flags) 2950{ 2951 unsigned long pfn_offset; 2952 unsigned long vaddr = *position; 2953 unsigned long remainder = *nr_pages; 2954 struct hstate *h = hstate_vma(vma); 2955 2956 spin_lock(&mm->page_table_lock); 2957 while (vaddr < vma->vm_end && remainder) { 2958 pte_t *pte; 2959 int absent; 2960 struct page *page; 2961 2962 /* 2963 * Some archs (sparc64, sh*) have multiple pte_ts to 2964 * each hugepage. We have to make sure we get the 2965 * first, for the page indexing below to work. 2966 */ 2967 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2968 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 2969 2970 /* 2971 * When coredumping, it suits get_dump_page if we just return 2972 * an error where there's an empty slot with no huge pagecache 2973 * to back it. This way, we avoid allocating a hugepage, and 2974 * the sparse dumpfile avoids allocating disk blocks, but its 2975 * huge holes still show up with zeroes where they need to be. 2976 */ 2977 if (absent && (flags & FOLL_DUMP) && 2978 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 2979 remainder = 0; 2980 break; 2981 } 2982 2983 /* 2984 * We need call hugetlb_fault for both hugepages under migration 2985 * (in which case hugetlb_fault waits for the migration,) and 2986 * hwpoisoned hugepages (in which case we need to prevent the 2987 * caller from accessing to them.) In order to do this, we use 2988 * here is_swap_pte instead of is_hugetlb_entry_migration and 2989 * is_hugetlb_entry_hwpoisoned. This is because it simply covers 2990 * both cases, and because we can't follow correct pages 2991 * directly from any kind of swap entries. 2992 */ 2993 if (absent || is_swap_pte(huge_ptep_get(pte)) || 2994 ((flags & FOLL_WRITE) && 2995 !huge_pte_write(huge_ptep_get(pte)))) { 2996 int ret; 2997 2998 spin_unlock(&mm->page_table_lock); 2999 ret = hugetlb_fault(mm, vma, vaddr, 3000 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 3001 spin_lock(&mm->page_table_lock); 3002 if (!(ret & VM_FAULT_ERROR)) 3003 continue; 3004 3005 remainder = 0; 3006 break; 3007 } 3008 3009 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 3010 page = pte_page(huge_ptep_get(pte)); 3011same_page: 3012 if (pages) { 3013 pages[i] = mem_map_offset(page, pfn_offset); 3014 get_page(pages[i]); 3015 } 3016 3017 if (vmas) 3018 vmas[i] = vma; 3019 3020 vaddr += PAGE_SIZE; 3021 ++pfn_offset; 3022 --remainder; 3023 ++i; 3024 if (vaddr < vma->vm_end && remainder && 3025 pfn_offset < pages_per_huge_page(h)) { 3026 /* 3027 * We use pfn_offset to avoid touching the pageframes 3028 * of this compound page. 3029 */ 3030 goto same_page; 3031 } 3032 } 3033 spin_unlock(&mm->page_table_lock); 3034 *nr_pages = remainder; 3035 *position = vaddr; 3036 3037 return i ? i : -EFAULT; 3038} 3039 3040unsigned long hugetlb_change_protection(struct vm_area_struct *vma, 3041 unsigned long address, unsigned long end, pgprot_t newprot) 3042{ 3043 struct mm_struct *mm = vma->vm_mm; 3044 unsigned long start = address; 3045 pte_t *ptep; 3046 pte_t pte; 3047 struct hstate *h = hstate_vma(vma); 3048 unsigned long pages = 0; 3049 3050 BUG_ON(address >= end); 3051 flush_cache_range(vma, address, end); 3052 3053 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 3054 spin_lock(&mm->page_table_lock); 3055 for (; address < end; address += huge_page_size(h)) { 3056 ptep = huge_pte_offset(mm, address); 3057 if (!ptep) 3058 continue; 3059 if (huge_pmd_unshare(mm, &address, ptep)) { 3060 pages++; 3061 continue; 3062 } 3063 if (!huge_pte_none(huge_ptep_get(ptep))) { 3064 pte = huge_ptep_get_and_clear(mm, address, ptep); 3065 pte = pte_mkhuge(huge_pte_modify(pte, newprot)); 3066 pte = arch_make_huge_pte(pte, vma, NULL, 0); 3067 set_huge_pte_at(mm, address, ptep, pte); 3068 pages++; 3069 } 3070 } 3071 spin_unlock(&mm->page_table_lock); 3072 /* 3073 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare 3074 * may have cleared our pud entry and done put_page on the page table: 3075 * once we release i_mmap_mutex, another task can do the final put_page 3076 * and that page table be reused and filled with junk. 3077 */ 3078 flush_tlb_range(vma, start, end); 3079 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 3080 3081 return pages << h->order; 3082} 3083 3084int hugetlb_reserve_pages(struct inode *inode, 3085 long from, long to, 3086 struct vm_area_struct *vma, 3087 vm_flags_t vm_flags) 3088{ 3089 long ret, chg; 3090 struct hstate *h = hstate_inode(inode); 3091 struct hugepage_subpool *spool = subpool_inode(inode); 3092 3093 /* 3094 * Only apply hugepage reservation if asked. At fault time, an 3095 * attempt will be made for VM_NORESERVE to allocate a page 3096 * without using reserves 3097 */ 3098 if (vm_flags & VM_NORESERVE) 3099 return 0; 3100 3101 /* 3102 * Shared mappings base their reservation on the number of pages that 3103 * are already allocated on behalf of the file. Private mappings need 3104 * to reserve the full area even if read-only as mprotect() may be 3105 * called to make the mapping read-write. Assume !vma is a shm mapping 3106 */ 3107 if (!vma || vma->vm_flags & VM_MAYSHARE) 3108 chg = region_chg(&inode->i_mapping->private_list, from, to); 3109 else { 3110 struct resv_map *resv_map = resv_map_alloc(); 3111 if (!resv_map) 3112 return -ENOMEM; 3113 3114 chg = to - from; 3115 3116 set_vma_resv_map(vma, resv_map); 3117 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 3118 } 3119 3120 if (chg < 0) { 3121 ret = chg; 3122 goto out_err; 3123 } 3124 3125 /* There must be enough pages in the subpool for the mapping */ 3126 if (hugepage_subpool_get_pages(spool, chg)) { 3127 ret = -ENOSPC; 3128 goto out_err; 3129 } 3130 3131 /* 3132 * Check enough hugepages are available for the reservation. 3133 * Hand the pages back to the subpool if there are not 3134 */ 3135 ret = hugetlb_acct_memory(h, chg); 3136 if (ret < 0) { 3137 hugepage_subpool_put_pages(spool, chg); 3138 goto out_err; 3139 } 3140 3141 /* 3142 * Account for the reservations made. Shared mappings record regions 3143 * that have reservations as they are shared by multiple VMAs. 3144 * When the last VMA disappears, the region map says how much 3145 * the reservation was and the page cache tells how much of 3146 * the reservation was consumed. Private mappings are per-VMA and 3147 * only the consumed reservations are tracked. When the VMA 3148 * disappears, the original reservation is the VMA size and the 3149 * consumed reservations are stored in the map. Hence, nothing 3150 * else has to be done for private mappings here 3151 */ 3152 if (!vma || vma->vm_flags & VM_MAYSHARE) 3153 region_add(&inode->i_mapping->private_list, from, to); 3154 return 0; 3155out_err: 3156 if (vma) 3157 resv_map_put(vma); 3158 return ret; 3159} 3160 3161void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 3162{ 3163 struct hstate *h = hstate_inode(inode); 3164 long chg = region_truncate(&inode->i_mapping->private_list, offset); 3165 struct hugepage_subpool *spool = subpool_inode(inode); 3166 3167 spin_lock(&inode->i_lock); 3168 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 3169 spin_unlock(&inode->i_lock); 3170 3171 hugepage_subpool_put_pages(spool, (chg - freed)); 3172 hugetlb_acct_memory(h, -(chg - freed)); 3173} 3174 3175#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE 3176static unsigned long page_table_shareable(struct vm_area_struct *svma, 3177 struct vm_area_struct *vma, 3178 unsigned long addr, pgoff_t idx) 3179{ 3180 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + 3181 svma->vm_start; 3182 unsigned long sbase = saddr & PUD_MASK; 3183 unsigned long s_end = sbase + PUD_SIZE; 3184 3185 /* Allow segments to share if only one is marked locked */ 3186 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED; 3187 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED; 3188 3189 /* 3190 * match the virtual addresses, permission and the alignment of the 3191 * page table page. 3192 */ 3193 if (pmd_index(addr) != pmd_index(saddr) || 3194 vm_flags != svm_flags || 3195 sbase < svma->vm_start || svma->vm_end < s_end) 3196 return 0; 3197 3198 return saddr; 3199} 3200 3201static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) 3202{ 3203 unsigned long base = addr & PUD_MASK; 3204 unsigned long end = base + PUD_SIZE; 3205 3206 /* 3207 * check on proper vm_flags and page table alignment 3208 */ 3209 if (vma->vm_flags & VM_MAYSHARE && 3210 vma->vm_start <= base && end <= vma->vm_end) 3211 return 1; 3212 return 0; 3213} 3214 3215/* 3216 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() 3217 * and returns the corresponding pte. While this is not necessary for the 3218 * !shared pmd case because we can allocate the pmd later as well, it makes the 3219 * code much cleaner. pmd allocation is essential for the shared case because 3220 * pud has to be populated inside the same i_mmap_mutex section - otherwise 3221 * racing tasks could either miss the sharing (see huge_pte_offset) or select a 3222 * bad pmd for sharing. 3223 */ 3224pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) 3225{ 3226 struct vm_area_struct *vma = find_vma(mm, addr); 3227 struct address_space *mapping = vma->vm_file->f_mapping; 3228 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + 3229 vma->vm_pgoff; 3230 struct vm_area_struct *svma; 3231 unsigned long saddr; 3232 pte_t *spte = NULL; 3233 pte_t *pte; 3234 3235 if (!vma_shareable(vma, addr)) 3236 return (pte_t *)pmd_alloc(mm, pud, addr); 3237 3238 mutex_lock(&mapping->i_mmap_mutex); 3239 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { 3240 if (svma == vma) 3241 continue; 3242 3243 saddr = page_table_shareable(svma, vma, addr, idx); 3244 if (saddr) { 3245 spte = huge_pte_offset(svma->vm_mm, saddr); 3246 if (spte) { 3247 get_page(virt_to_page(spte)); 3248 break; 3249 } 3250 } 3251 } 3252 3253 if (!spte) 3254 goto out; 3255 3256 spin_lock(&mm->page_table_lock); 3257 if (pud_none(*pud)) 3258 pud_populate(mm, pud, 3259 (pmd_t *)((unsigned long)spte & PAGE_MASK)); 3260 else 3261 put_page(virt_to_page(spte)); 3262 spin_unlock(&mm->page_table_lock); 3263out: 3264 pte = (pte_t *)pmd_alloc(mm, pud, addr); 3265 mutex_unlock(&mapping->i_mmap_mutex); 3266 return pte; 3267} 3268 3269/* 3270 * unmap huge page backed by shared pte. 3271 * 3272 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared 3273 * indicated by page_count > 1, unmap is achieved by clearing pud and 3274 * decrementing the ref count. If count == 1, the pte page is not shared. 3275 * 3276 * called with vma->vm_mm->page_table_lock held. 3277 * 3278 * returns: 1 successfully unmapped a shared pte page 3279 * 0 the underlying pte page is not shared, or it is the last user 3280 */ 3281int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) 3282{ 3283 pgd_t *pgd = pgd_offset(mm, *addr); 3284 pud_t *pud = pud_offset(pgd, *addr); 3285 3286 BUG_ON(page_count(virt_to_page(ptep)) == 0); 3287 if (page_count(virt_to_page(ptep)) == 1) 3288 return 0; 3289 3290 pud_clear(pud); 3291 put_page(virt_to_page(ptep)); 3292 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; 3293 return 1; 3294} 3295#define want_pmd_share() (1) 3296#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ 3297pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) 3298{ 3299 return NULL; 3300} 3301#define want_pmd_share() (0) 3302#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ 3303 3304#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB 3305pte_t *huge_pte_alloc(struct mm_struct *mm, 3306 unsigned long addr, unsigned long sz) 3307{ 3308 pgd_t *pgd; 3309 pud_t *pud; 3310 pte_t *pte = NULL; 3311 3312 pgd = pgd_offset(mm, addr); 3313 pud = pud_alloc(mm, pgd, addr); 3314 if (pud) { 3315 if (sz == PUD_SIZE) { 3316 pte = (pte_t *)pud; 3317 } else { 3318 BUG_ON(sz != PMD_SIZE); 3319 if (want_pmd_share() && pud_none(*pud)) 3320 pte = huge_pmd_share(mm, addr, pud); 3321 else 3322 pte = (pte_t *)pmd_alloc(mm, pud, addr); 3323 } 3324 } 3325 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); 3326 3327 return pte; 3328} 3329 3330pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 3331{ 3332 pgd_t *pgd; 3333 pud_t *pud; 3334 pmd_t *pmd = NULL; 3335 3336 pgd = pgd_offset(mm, addr); 3337 if (pgd_present(*pgd)) { 3338 pud = pud_offset(pgd, addr); 3339 if (pud_present(*pud)) { 3340 if (pud_huge(*pud)) 3341 return (pte_t *)pud; 3342 pmd = pmd_offset(pud, addr); 3343 } 3344 } 3345 return (pte_t *) pmd; 3346} 3347 3348struct page * 3349follow_huge_pmd(struct mm_struct *mm, unsigned long address, 3350 pmd_t *pmd, int write) 3351{ 3352 struct page *page; 3353 3354 page = pte_page(*(pte_t *)pmd); 3355 if (page) 3356 page += ((address & ~PMD_MASK) >> PAGE_SHIFT); 3357 return page; 3358} 3359 3360struct page * 3361follow_huge_pud(struct mm_struct *mm, unsigned long address, 3362 pud_t *pud, int write) 3363{ 3364 struct page *page; 3365 3366 page = pte_page(*(pte_t *)pud); 3367 if (page) 3368 page += ((address & ~PUD_MASK) >> PAGE_SHIFT); 3369 return page; 3370} 3371 3372#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ 3373 3374/* Can be overriden by architectures */ 3375__attribute__((weak)) struct page * 3376follow_huge_pud(struct mm_struct *mm, unsigned long address, 3377 pud_t *pud, int write) 3378{ 3379 BUG(); 3380 return NULL; 3381} 3382 3383#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ 3384 3385#ifdef CONFIG_MEMORY_FAILURE 3386 3387/* Should be called in hugetlb_lock */ 3388static int is_hugepage_on_freelist(struct page *hpage) 3389{ 3390 struct page *page; 3391 struct page *tmp; 3392 struct hstate *h = page_hstate(hpage); 3393 int nid = page_to_nid(hpage); 3394 3395 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) 3396 if (page == hpage) 3397 return 1; 3398 return 0; 3399} 3400 3401/* 3402 * This function is called from memory failure code. 3403 * Assume the caller holds page lock of the head page. 3404 */ 3405int dequeue_hwpoisoned_huge_page(struct page *hpage) 3406{ 3407 struct hstate *h = page_hstate(hpage); 3408 int nid = page_to_nid(hpage); 3409 int ret = -EBUSY; 3410 3411 spin_lock(&hugetlb_lock); 3412 if (is_hugepage_on_freelist(hpage)) { 3413 /* 3414 * Hwpoisoned hugepage isn't linked to activelist or freelist, 3415 * but dangling hpage->lru can trigger list-debug warnings 3416 * (this happens when we call unpoison_memory() on it), 3417 * so let it point to itself with list_del_init(). 3418 */ 3419 list_del_init(&hpage->lru); 3420 set_page_refcounted(hpage); 3421 h->free_huge_pages--; 3422 h->free_huge_pages_node[nid]--; 3423 ret = 0; 3424 } 3425 spin_unlock(&hugetlb_lock); 3426 return ret; 3427} 3428#endif 3429