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