hugetlb.c revision 8382d914ebf72092aa15cdc2a5dcedb2daa0209d
1/* 2 * Generic hugetlb support. 3 * (C) Nadia Yvette Chambers, April 2004 4 */ 5#include <linux/list.h> 6#include <linux/init.h> 7#include <linux/module.h> 8#include <linux/mm.h> 9#include <linux/seq_file.h> 10#include <linux/sysctl.h> 11#include <linux/highmem.h> 12#include <linux/mmu_notifier.h> 13#include <linux/nodemask.h> 14#include <linux/pagemap.h> 15#include <linux/mempolicy.h> 16#include <linux/cpuset.h> 17#include <linux/mutex.h> 18#include <linux/bootmem.h> 19#include <linux/sysfs.h> 20#include <linux/slab.h> 21#include <linux/rmap.h> 22#include <linux/swap.h> 23#include <linux/swapops.h> 24#include <linux/page-isolation.h> 25#include <linux/jhash.h> 26 27#include <asm/page.h> 28#include <asm/pgtable.h> 29#include <asm/tlb.h> 30 31#include <linux/io.h> 32#include <linux/hugetlb.h> 33#include <linux/hugetlb_cgroup.h> 34#include <linux/node.h> 35#include "internal.h" 36 37const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 38unsigned long hugepages_treat_as_movable; 39 40int hugetlb_max_hstate __read_mostly; 41unsigned int default_hstate_idx; 42struct hstate hstates[HUGE_MAX_HSTATE]; 43 44__initdata LIST_HEAD(huge_boot_pages); 45 46/* for command line parsing */ 47static struct hstate * __initdata parsed_hstate; 48static unsigned long __initdata default_hstate_max_huge_pages; 49static unsigned long __initdata default_hstate_size; 50 51/* 52 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, 53 * free_huge_pages, and surplus_huge_pages. 54 */ 55DEFINE_SPINLOCK(hugetlb_lock); 56 57/* 58 * Serializes faults on the same logical page. This is used to 59 * prevent spurious OOMs when the hugepage pool is fully utilized. 60 */ 61static int num_fault_mutexes; 62static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp; 63 64static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) 65{ 66 bool free = (spool->count == 0) && (spool->used_hpages == 0); 67 68 spin_unlock(&spool->lock); 69 70 /* If no pages are used, and no other handles to the subpool 71 * remain, free the subpool the subpool remain */ 72 if (free) 73 kfree(spool); 74} 75 76struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) 77{ 78 struct hugepage_subpool *spool; 79 80 spool = kmalloc(sizeof(*spool), GFP_KERNEL); 81 if (!spool) 82 return NULL; 83 84 spin_lock_init(&spool->lock); 85 spool->count = 1; 86 spool->max_hpages = nr_blocks; 87 spool->used_hpages = 0; 88 89 return spool; 90} 91 92void hugepage_put_subpool(struct hugepage_subpool *spool) 93{ 94 spin_lock(&spool->lock); 95 BUG_ON(!spool->count); 96 spool->count--; 97 unlock_or_release_subpool(spool); 98} 99 100static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, 101 long delta) 102{ 103 int ret = 0; 104 105 if (!spool) 106 return 0; 107 108 spin_lock(&spool->lock); 109 if ((spool->used_hpages + delta) <= spool->max_hpages) { 110 spool->used_hpages += delta; 111 } else { 112 ret = -ENOMEM; 113 } 114 spin_unlock(&spool->lock); 115 116 return ret; 117} 118 119static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, 120 long delta) 121{ 122 if (!spool) 123 return; 124 125 spin_lock(&spool->lock); 126 spool->used_hpages -= delta; 127 /* If hugetlbfs_put_super couldn't free spool due to 128 * an outstanding quota reference, free it now. */ 129 unlock_or_release_subpool(spool); 130} 131 132static inline struct hugepage_subpool *subpool_inode(struct inode *inode) 133{ 134 return HUGETLBFS_SB(inode->i_sb)->spool; 135} 136 137static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) 138{ 139 return subpool_inode(file_inode(vma->vm_file)); 140} 141 142/* 143 * Region tracking -- allows tracking of reservations and instantiated pages 144 * across the pages in a mapping. 145 * 146 * The region data structures are embedded into a resv_map and 147 * protected by a resv_map's lock 148 */ 149struct file_region { 150 struct list_head link; 151 long from; 152 long to; 153}; 154 155static long region_add(struct resv_map *resv, long f, long t) 156{ 157 struct list_head *head = &resv->regions; 158 struct file_region *rg, *nrg, *trg; 159 160 spin_lock(&resv->lock); 161 /* Locate the region we are either in or before. */ 162 list_for_each_entry(rg, head, link) 163 if (f <= rg->to) 164 break; 165 166 /* Round our left edge to the current segment if it encloses us. */ 167 if (f > rg->from) 168 f = rg->from; 169 170 /* Check for and consume any regions we now overlap with. */ 171 nrg = rg; 172 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 173 if (&rg->link == head) 174 break; 175 if (rg->from > t) 176 break; 177 178 /* If this area reaches higher then extend our area to 179 * include it completely. If this is not the first area 180 * which we intend to reuse, free it. */ 181 if (rg->to > t) 182 t = rg->to; 183 if (rg != nrg) { 184 list_del(&rg->link); 185 kfree(rg); 186 } 187 } 188 nrg->from = f; 189 nrg->to = t; 190 spin_unlock(&resv->lock); 191 return 0; 192} 193 194static long region_chg(struct resv_map *resv, long f, long t) 195{ 196 struct list_head *head = &resv->regions; 197 struct file_region *rg, *nrg = NULL; 198 long chg = 0; 199 200retry: 201 spin_lock(&resv->lock); 202 /* Locate the region we are before or in. */ 203 list_for_each_entry(rg, head, link) 204 if (f <= rg->to) 205 break; 206 207 /* If we are below the current region then a new region is required. 208 * Subtle, allocate a new region at the position but make it zero 209 * size such that we can guarantee to record the reservation. */ 210 if (&rg->link == head || t < rg->from) { 211 if (!nrg) { 212 spin_unlock(&resv->lock); 213 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 214 if (!nrg) 215 return -ENOMEM; 216 217 nrg->from = f; 218 nrg->to = f; 219 INIT_LIST_HEAD(&nrg->link); 220 goto retry; 221 } 222 223 list_add(&nrg->link, rg->link.prev); 224 chg = t - f; 225 goto out_nrg; 226 } 227 228 /* Round our left edge to the current segment if it encloses us. */ 229 if (f > rg->from) 230 f = rg->from; 231 chg = t - f; 232 233 /* Check for and consume any regions we now overlap with. */ 234 list_for_each_entry(rg, rg->link.prev, link) { 235 if (&rg->link == head) 236 break; 237 if (rg->from > t) 238 goto out; 239 240 /* We overlap with this area, if it extends further than 241 * us then we must extend ourselves. Account for its 242 * existing reservation. */ 243 if (rg->to > t) { 244 chg += rg->to - t; 245 t = rg->to; 246 } 247 chg -= rg->to - rg->from; 248 } 249 250out: 251 spin_unlock(&resv->lock); 252 /* We already know we raced and no longer need the new region */ 253 kfree(nrg); 254 return chg; 255out_nrg: 256 spin_unlock(&resv->lock); 257 return chg; 258} 259 260static long region_truncate(struct resv_map *resv, long end) 261{ 262 struct list_head *head = &resv->regions; 263 struct file_region *rg, *trg; 264 long chg = 0; 265 266 spin_lock(&resv->lock); 267 /* Locate the region we are either in or before. */ 268 list_for_each_entry(rg, head, link) 269 if (end <= rg->to) 270 break; 271 if (&rg->link == head) 272 goto out; 273 274 /* If we are in the middle of a region then adjust it. */ 275 if (end > rg->from) { 276 chg = rg->to - end; 277 rg->to = end; 278 rg = list_entry(rg->link.next, typeof(*rg), link); 279 } 280 281 /* Drop any remaining regions. */ 282 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 283 if (&rg->link == head) 284 break; 285 chg += rg->to - rg->from; 286 list_del(&rg->link); 287 kfree(rg); 288 } 289 290out: 291 spin_unlock(&resv->lock); 292 return chg; 293} 294 295static long region_count(struct resv_map *resv, long f, long t) 296{ 297 struct list_head *head = &resv->regions; 298 struct file_region *rg; 299 long chg = 0; 300 301 spin_lock(&resv->lock); 302 /* Locate each segment we overlap with, and count that overlap. */ 303 list_for_each_entry(rg, head, link) { 304 long seg_from; 305 long seg_to; 306 307 if (rg->to <= f) 308 continue; 309 if (rg->from >= t) 310 break; 311 312 seg_from = max(rg->from, f); 313 seg_to = min(rg->to, t); 314 315 chg += seg_to - seg_from; 316 } 317 spin_unlock(&resv->lock); 318 319 return chg; 320} 321 322/* 323 * Convert the address within this vma to the page offset within 324 * the mapping, in pagecache page units; huge pages here. 325 */ 326static pgoff_t vma_hugecache_offset(struct hstate *h, 327 struct vm_area_struct *vma, unsigned long address) 328{ 329 return ((address - vma->vm_start) >> huge_page_shift(h)) + 330 (vma->vm_pgoff >> huge_page_order(h)); 331} 332 333pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 334 unsigned long address) 335{ 336 return vma_hugecache_offset(hstate_vma(vma), vma, address); 337} 338 339/* 340 * Return the size of the pages allocated when backing a VMA. In the majority 341 * cases this will be same size as used by the page table entries. 342 */ 343unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) 344{ 345 struct hstate *hstate; 346 347 if (!is_vm_hugetlb_page(vma)) 348 return PAGE_SIZE; 349 350 hstate = hstate_vma(vma); 351 352 return 1UL << huge_page_shift(hstate); 353} 354EXPORT_SYMBOL_GPL(vma_kernel_pagesize); 355 356/* 357 * Return the page size being used by the MMU to back a VMA. In the majority 358 * of cases, the page size used by the kernel matches the MMU size. On 359 * architectures where it differs, an architecture-specific version of this 360 * function is required. 361 */ 362#ifndef vma_mmu_pagesize 363unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 364{ 365 return vma_kernel_pagesize(vma); 366} 367#endif 368 369/* 370 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 371 * bits of the reservation map pointer, which are always clear due to 372 * alignment. 373 */ 374#define HPAGE_RESV_OWNER (1UL << 0) 375#define HPAGE_RESV_UNMAPPED (1UL << 1) 376#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 377 378/* 379 * These helpers are used to track how many pages are reserved for 380 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 381 * is guaranteed to have their future faults succeed. 382 * 383 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 384 * the reserve counters are updated with the hugetlb_lock held. It is safe 385 * to reset the VMA at fork() time as it is not in use yet and there is no 386 * chance of the global counters getting corrupted as a result of the values. 387 * 388 * The private mapping reservation is represented in a subtly different 389 * manner to a shared mapping. A shared mapping has a region map associated 390 * with the underlying file, this region map represents the backing file 391 * pages which have ever had a reservation assigned which this persists even 392 * after the page is instantiated. A private mapping has a region map 393 * associated with the original mmap which is attached to all VMAs which 394 * reference it, this region map represents those offsets which have consumed 395 * reservation ie. where pages have been instantiated. 396 */ 397static unsigned long get_vma_private_data(struct vm_area_struct *vma) 398{ 399 return (unsigned long)vma->vm_private_data; 400} 401 402static void set_vma_private_data(struct vm_area_struct *vma, 403 unsigned long value) 404{ 405 vma->vm_private_data = (void *)value; 406} 407 408struct resv_map *resv_map_alloc(void) 409{ 410 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 411 if (!resv_map) 412 return NULL; 413 414 kref_init(&resv_map->refs); 415 spin_lock_init(&resv_map->lock); 416 INIT_LIST_HEAD(&resv_map->regions); 417 418 return resv_map; 419} 420 421void resv_map_release(struct kref *ref) 422{ 423 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 424 425 /* Clear out any active regions before we release the map. */ 426 region_truncate(resv_map, 0); 427 kfree(resv_map); 428} 429 430static inline struct resv_map *inode_resv_map(struct inode *inode) 431{ 432 return inode->i_mapping->private_data; 433} 434 435static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 436{ 437 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 438 if (vma->vm_flags & VM_MAYSHARE) { 439 struct address_space *mapping = vma->vm_file->f_mapping; 440 struct inode *inode = mapping->host; 441 442 return inode_resv_map(inode); 443 444 } else { 445 return (struct resv_map *)(get_vma_private_data(vma) & 446 ~HPAGE_RESV_MASK); 447 } 448} 449 450static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 451{ 452 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 453 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 454 455 set_vma_private_data(vma, (get_vma_private_data(vma) & 456 HPAGE_RESV_MASK) | (unsigned long)map); 457} 458 459static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 460{ 461 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 462 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 463 464 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 465} 466 467static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 468{ 469 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 470 471 return (get_vma_private_data(vma) & flag) != 0; 472} 473 474/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 475void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 476{ 477 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 478 if (!(vma->vm_flags & VM_MAYSHARE)) 479 vma->vm_private_data = (void *)0; 480} 481 482/* Returns true if the VMA has associated reserve pages */ 483static int vma_has_reserves(struct vm_area_struct *vma, long chg) 484{ 485 if (vma->vm_flags & VM_NORESERVE) { 486 /* 487 * This address is already reserved by other process(chg == 0), 488 * so, we should decrement reserved count. Without decrementing, 489 * reserve count remains after releasing inode, because this 490 * allocated page will go into page cache and is regarded as 491 * coming from reserved pool in releasing step. Currently, we 492 * don't have any other solution to deal with this situation 493 * properly, so add work-around here. 494 */ 495 if (vma->vm_flags & VM_MAYSHARE && chg == 0) 496 return 1; 497 else 498 return 0; 499 } 500 501 /* Shared mappings always use reserves */ 502 if (vma->vm_flags & VM_MAYSHARE) 503 return 1; 504 505 /* 506 * Only the process that called mmap() has reserves for 507 * private mappings. 508 */ 509 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 510 return 1; 511 512 return 0; 513} 514 515static void enqueue_huge_page(struct hstate *h, struct page *page) 516{ 517 int nid = page_to_nid(page); 518 list_move(&page->lru, &h->hugepage_freelists[nid]); 519 h->free_huge_pages++; 520 h->free_huge_pages_node[nid]++; 521} 522 523static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 524{ 525 struct page *page; 526 527 list_for_each_entry(page, &h->hugepage_freelists[nid], lru) 528 if (!is_migrate_isolate_page(page)) 529 break; 530 /* 531 * if 'non-isolated free hugepage' not found on the list, 532 * the allocation fails. 533 */ 534 if (&h->hugepage_freelists[nid] == &page->lru) 535 return NULL; 536 list_move(&page->lru, &h->hugepage_activelist); 537 set_page_refcounted(page); 538 h->free_huge_pages--; 539 h->free_huge_pages_node[nid]--; 540 return page; 541} 542 543/* Movability of hugepages depends on migration support. */ 544static inline gfp_t htlb_alloc_mask(struct hstate *h) 545{ 546 if (hugepages_treat_as_movable || hugepage_migration_support(h)) 547 return GFP_HIGHUSER_MOVABLE; 548 else 549 return GFP_HIGHUSER; 550} 551 552static struct page *dequeue_huge_page_vma(struct hstate *h, 553 struct vm_area_struct *vma, 554 unsigned long address, int avoid_reserve, 555 long chg) 556{ 557 struct page *page = NULL; 558 struct mempolicy *mpol; 559 nodemask_t *nodemask; 560 struct zonelist *zonelist; 561 struct zone *zone; 562 struct zoneref *z; 563 unsigned int cpuset_mems_cookie; 564 565 /* 566 * A child process with MAP_PRIVATE mappings created by their parent 567 * have no page reserves. This check ensures that reservations are 568 * not "stolen". The child may still get SIGKILLed 569 */ 570 if (!vma_has_reserves(vma, chg) && 571 h->free_huge_pages - h->resv_huge_pages == 0) 572 goto err; 573 574 /* If reserves cannot be used, ensure enough pages are in the pool */ 575 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 576 goto err; 577 578retry_cpuset: 579 cpuset_mems_cookie = read_mems_allowed_begin(); 580 zonelist = huge_zonelist(vma, address, 581 htlb_alloc_mask(h), &mpol, &nodemask); 582 583 for_each_zone_zonelist_nodemask(zone, z, zonelist, 584 MAX_NR_ZONES - 1, nodemask) { 585 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) { 586 page = dequeue_huge_page_node(h, zone_to_nid(zone)); 587 if (page) { 588 if (avoid_reserve) 589 break; 590 if (!vma_has_reserves(vma, chg)) 591 break; 592 593 SetPagePrivate(page); 594 h->resv_huge_pages--; 595 break; 596 } 597 } 598 } 599 600 mpol_cond_put(mpol); 601 if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) 602 goto retry_cpuset; 603 return page; 604 605err: 606 return NULL; 607} 608 609static void update_and_free_page(struct hstate *h, struct page *page) 610{ 611 int i; 612 613 VM_BUG_ON(h->order >= MAX_ORDER); 614 615 h->nr_huge_pages--; 616 h->nr_huge_pages_node[page_to_nid(page)]--; 617 for (i = 0; i < pages_per_huge_page(h); i++) { 618 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 619 1 << PG_referenced | 1 << PG_dirty | 620 1 << PG_active | 1 << PG_reserved | 621 1 << PG_private | 1 << PG_writeback); 622 } 623 VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); 624 set_compound_page_dtor(page, NULL); 625 set_page_refcounted(page); 626 arch_release_hugepage(page); 627 __free_pages(page, huge_page_order(h)); 628} 629 630struct hstate *size_to_hstate(unsigned long size) 631{ 632 struct hstate *h; 633 634 for_each_hstate(h) { 635 if (huge_page_size(h) == size) 636 return h; 637 } 638 return NULL; 639} 640 641static void free_huge_page(struct page *page) 642{ 643 /* 644 * Can't pass hstate in here because it is called from the 645 * compound page destructor. 646 */ 647 struct hstate *h = page_hstate(page); 648 int nid = page_to_nid(page); 649 struct hugepage_subpool *spool = 650 (struct hugepage_subpool *)page_private(page); 651 bool restore_reserve; 652 653 set_page_private(page, 0); 654 page->mapping = NULL; 655 BUG_ON(page_count(page)); 656 BUG_ON(page_mapcount(page)); 657 restore_reserve = PagePrivate(page); 658 ClearPagePrivate(page); 659 660 spin_lock(&hugetlb_lock); 661 hugetlb_cgroup_uncharge_page(hstate_index(h), 662 pages_per_huge_page(h), page); 663 if (restore_reserve) 664 h->resv_huge_pages++; 665 666 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 667 /* remove the page from active list */ 668 list_del(&page->lru); 669 update_and_free_page(h, page); 670 h->surplus_huge_pages--; 671 h->surplus_huge_pages_node[nid]--; 672 } else { 673 arch_clear_hugepage_flags(page); 674 enqueue_huge_page(h, page); 675 } 676 spin_unlock(&hugetlb_lock); 677 hugepage_subpool_put_pages(spool, 1); 678} 679 680static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 681{ 682 INIT_LIST_HEAD(&page->lru); 683 set_compound_page_dtor(page, free_huge_page); 684 spin_lock(&hugetlb_lock); 685 set_hugetlb_cgroup(page, NULL); 686 h->nr_huge_pages++; 687 h->nr_huge_pages_node[nid]++; 688 spin_unlock(&hugetlb_lock); 689 put_page(page); /* free it into the hugepage allocator */ 690} 691 692static void prep_compound_gigantic_page(struct page *page, unsigned long order) 693{ 694 int i; 695 int nr_pages = 1 << order; 696 struct page *p = page + 1; 697 698 /* we rely on prep_new_huge_page to set the destructor */ 699 set_compound_order(page, order); 700 __SetPageHead(page); 701 __ClearPageReserved(page); 702 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 703 __SetPageTail(p); 704 /* 705 * For gigantic hugepages allocated through bootmem at 706 * boot, it's safer to be consistent with the not-gigantic 707 * hugepages and clear the PG_reserved bit from all tail pages 708 * too. Otherwse drivers using get_user_pages() to access tail 709 * pages may get the reference counting wrong if they see 710 * PG_reserved set on a tail page (despite the head page not 711 * having PG_reserved set). Enforcing this consistency between 712 * head and tail pages allows drivers to optimize away a check 713 * on the head page when they need know if put_page() is needed 714 * after get_user_pages(). 715 */ 716 __ClearPageReserved(p); 717 set_page_count(p, 0); 718 p->first_page = page; 719 } 720} 721 722/* 723 * PageHuge() only returns true for hugetlbfs pages, but not for normal or 724 * transparent huge pages. See the PageTransHuge() documentation for more 725 * details. 726 */ 727int PageHuge(struct page *page) 728{ 729 if (!PageCompound(page)) 730 return 0; 731 732 page = compound_head(page); 733 return get_compound_page_dtor(page) == free_huge_page; 734} 735EXPORT_SYMBOL_GPL(PageHuge); 736 737/* 738 * PageHeadHuge() only returns true for hugetlbfs head page, but not for 739 * normal or transparent huge pages. 740 */ 741int PageHeadHuge(struct page *page_head) 742{ 743 if (!PageHead(page_head)) 744 return 0; 745 746 return get_compound_page_dtor(page_head) == free_huge_page; 747} 748 749pgoff_t __basepage_index(struct page *page) 750{ 751 struct page *page_head = compound_head(page); 752 pgoff_t index = page_index(page_head); 753 unsigned long compound_idx; 754 755 if (!PageHuge(page_head)) 756 return page_index(page); 757 758 if (compound_order(page_head) >= MAX_ORDER) 759 compound_idx = page_to_pfn(page) - page_to_pfn(page_head); 760 else 761 compound_idx = page - page_head; 762 763 return (index << compound_order(page_head)) + compound_idx; 764} 765 766static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 767{ 768 struct page *page; 769 770 if (h->order >= MAX_ORDER) 771 return NULL; 772 773 page = alloc_pages_exact_node(nid, 774 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| 775 __GFP_REPEAT|__GFP_NOWARN, 776 huge_page_order(h)); 777 if (page) { 778 if (arch_prepare_hugepage(page)) { 779 __free_pages(page, huge_page_order(h)); 780 return NULL; 781 } 782 prep_new_huge_page(h, page, nid); 783 } 784 785 return page; 786} 787 788/* 789 * common helper functions for hstate_next_node_to_{alloc|free}. 790 * We may have allocated or freed a huge page based on a different 791 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 792 * be outside of *nodes_allowed. Ensure that we use an allowed 793 * node for alloc or free. 794 */ 795static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 796{ 797 nid = next_node(nid, *nodes_allowed); 798 if (nid == MAX_NUMNODES) 799 nid = first_node(*nodes_allowed); 800 VM_BUG_ON(nid >= MAX_NUMNODES); 801 802 return nid; 803} 804 805static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 806{ 807 if (!node_isset(nid, *nodes_allowed)) 808 nid = next_node_allowed(nid, nodes_allowed); 809 return nid; 810} 811 812/* 813 * returns the previously saved node ["this node"] from which to 814 * allocate a persistent huge page for the pool and advance the 815 * next node from which to allocate, handling wrap at end of node 816 * mask. 817 */ 818static int hstate_next_node_to_alloc(struct hstate *h, 819 nodemask_t *nodes_allowed) 820{ 821 int nid; 822 823 VM_BUG_ON(!nodes_allowed); 824 825 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 826 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 827 828 return nid; 829} 830 831/* 832 * helper for free_pool_huge_page() - return the previously saved 833 * node ["this node"] from which to free a huge page. Advance the 834 * next node id whether or not we find a free huge page to free so 835 * that the next attempt to free addresses the next node. 836 */ 837static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 838{ 839 int nid; 840 841 VM_BUG_ON(!nodes_allowed); 842 843 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 844 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 845 846 return nid; 847} 848 849#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ 850 for (nr_nodes = nodes_weight(*mask); \ 851 nr_nodes > 0 && \ 852 ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ 853 nr_nodes--) 854 855#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ 856 for (nr_nodes = nodes_weight(*mask); \ 857 nr_nodes > 0 && \ 858 ((node = hstate_next_node_to_free(hs, mask)) || 1); \ 859 nr_nodes--) 860 861static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 862{ 863 struct page *page; 864 int nr_nodes, node; 865 int ret = 0; 866 867 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { 868 page = alloc_fresh_huge_page_node(h, node); 869 if (page) { 870 ret = 1; 871 break; 872 } 873 } 874 875 if (ret) 876 count_vm_event(HTLB_BUDDY_PGALLOC); 877 else 878 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 879 880 return ret; 881} 882 883/* 884 * Free huge page from pool from next node to free. 885 * Attempt to keep persistent huge pages more or less 886 * balanced over allowed nodes. 887 * Called with hugetlb_lock locked. 888 */ 889static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 890 bool acct_surplus) 891{ 892 int nr_nodes, node; 893 int ret = 0; 894 895 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { 896 /* 897 * If we're returning unused surplus pages, only examine 898 * nodes with surplus pages. 899 */ 900 if ((!acct_surplus || h->surplus_huge_pages_node[node]) && 901 !list_empty(&h->hugepage_freelists[node])) { 902 struct page *page = 903 list_entry(h->hugepage_freelists[node].next, 904 struct page, lru); 905 list_del(&page->lru); 906 h->free_huge_pages--; 907 h->free_huge_pages_node[node]--; 908 if (acct_surplus) { 909 h->surplus_huge_pages--; 910 h->surplus_huge_pages_node[node]--; 911 } 912 update_and_free_page(h, page); 913 ret = 1; 914 break; 915 } 916 } 917 918 return ret; 919} 920 921/* 922 * Dissolve a given free hugepage into free buddy pages. This function does 923 * nothing for in-use (including surplus) hugepages. 924 */ 925static void dissolve_free_huge_page(struct page *page) 926{ 927 spin_lock(&hugetlb_lock); 928 if (PageHuge(page) && !page_count(page)) { 929 struct hstate *h = page_hstate(page); 930 int nid = page_to_nid(page); 931 list_del(&page->lru); 932 h->free_huge_pages--; 933 h->free_huge_pages_node[nid]--; 934 update_and_free_page(h, page); 935 } 936 spin_unlock(&hugetlb_lock); 937} 938 939/* 940 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to 941 * make specified memory blocks removable from the system. 942 * Note that start_pfn should aligned with (minimum) hugepage size. 943 */ 944void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) 945{ 946 unsigned int order = 8 * sizeof(void *); 947 unsigned long pfn; 948 struct hstate *h; 949 950 /* Set scan step to minimum hugepage size */ 951 for_each_hstate(h) 952 if (order > huge_page_order(h)) 953 order = huge_page_order(h); 954 VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); 955 for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) 956 dissolve_free_huge_page(pfn_to_page(pfn)); 957} 958 959static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) 960{ 961 struct page *page; 962 unsigned int r_nid; 963 964 if (h->order >= MAX_ORDER) 965 return NULL; 966 967 /* 968 * Assume we will successfully allocate the surplus page to 969 * prevent racing processes from causing the surplus to exceed 970 * overcommit 971 * 972 * This however introduces a different race, where a process B 973 * tries to grow the static hugepage pool while alloc_pages() is 974 * called by process A. B will only examine the per-node 975 * counters in determining if surplus huge pages can be 976 * converted to normal huge pages in adjust_pool_surplus(). A 977 * won't be able to increment the per-node counter, until the 978 * lock is dropped by B, but B doesn't drop hugetlb_lock until 979 * no more huge pages can be converted from surplus to normal 980 * state (and doesn't try to convert again). Thus, we have a 981 * case where a surplus huge page exists, the pool is grown, and 982 * the surplus huge page still exists after, even though it 983 * should just have been converted to a normal huge page. This 984 * does not leak memory, though, as the hugepage will be freed 985 * once it is out of use. It also does not allow the counters to 986 * go out of whack in adjust_pool_surplus() as we don't modify 987 * the node values until we've gotten the hugepage and only the 988 * per-node value is checked there. 989 */ 990 spin_lock(&hugetlb_lock); 991 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 992 spin_unlock(&hugetlb_lock); 993 return NULL; 994 } else { 995 h->nr_huge_pages++; 996 h->surplus_huge_pages++; 997 } 998 spin_unlock(&hugetlb_lock); 999 1000 if (nid == NUMA_NO_NODE) 1001 page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP| 1002 __GFP_REPEAT|__GFP_NOWARN, 1003 huge_page_order(h)); 1004 else 1005 page = alloc_pages_exact_node(nid, 1006 htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| 1007 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); 1008 1009 if (page && arch_prepare_hugepage(page)) { 1010 __free_pages(page, huge_page_order(h)); 1011 page = NULL; 1012 } 1013 1014 spin_lock(&hugetlb_lock); 1015 if (page) { 1016 INIT_LIST_HEAD(&page->lru); 1017 r_nid = page_to_nid(page); 1018 set_compound_page_dtor(page, free_huge_page); 1019 set_hugetlb_cgroup(page, NULL); 1020 /* 1021 * We incremented the global counters already 1022 */ 1023 h->nr_huge_pages_node[r_nid]++; 1024 h->surplus_huge_pages_node[r_nid]++; 1025 __count_vm_event(HTLB_BUDDY_PGALLOC); 1026 } else { 1027 h->nr_huge_pages--; 1028 h->surplus_huge_pages--; 1029 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 1030 } 1031 spin_unlock(&hugetlb_lock); 1032 1033 return page; 1034} 1035 1036/* 1037 * This allocation function is useful in the context where vma is irrelevant. 1038 * E.g. soft-offlining uses this function because it only cares physical 1039 * address of error page. 1040 */ 1041struct page *alloc_huge_page_node(struct hstate *h, int nid) 1042{ 1043 struct page *page = NULL; 1044 1045 spin_lock(&hugetlb_lock); 1046 if (h->free_huge_pages - h->resv_huge_pages > 0) 1047 page = dequeue_huge_page_node(h, nid); 1048 spin_unlock(&hugetlb_lock); 1049 1050 if (!page) 1051 page = alloc_buddy_huge_page(h, nid); 1052 1053 return page; 1054} 1055 1056/* 1057 * Increase the hugetlb pool such that it can accommodate a reservation 1058 * of size 'delta'. 1059 */ 1060static int gather_surplus_pages(struct hstate *h, int delta) 1061{ 1062 struct list_head surplus_list; 1063 struct page *page, *tmp; 1064 int ret, i; 1065 int needed, allocated; 1066 bool alloc_ok = true; 1067 1068 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 1069 if (needed <= 0) { 1070 h->resv_huge_pages += delta; 1071 return 0; 1072 } 1073 1074 allocated = 0; 1075 INIT_LIST_HEAD(&surplus_list); 1076 1077 ret = -ENOMEM; 1078retry: 1079 spin_unlock(&hugetlb_lock); 1080 for (i = 0; i < needed; i++) { 1081 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1082 if (!page) { 1083 alloc_ok = false; 1084 break; 1085 } 1086 list_add(&page->lru, &surplus_list); 1087 } 1088 allocated += i; 1089 1090 /* 1091 * After retaking hugetlb_lock, we need to recalculate 'needed' 1092 * because either resv_huge_pages or free_huge_pages may have changed. 1093 */ 1094 spin_lock(&hugetlb_lock); 1095 needed = (h->resv_huge_pages + delta) - 1096 (h->free_huge_pages + allocated); 1097 if (needed > 0) { 1098 if (alloc_ok) 1099 goto retry; 1100 /* 1101 * We were not able to allocate enough pages to 1102 * satisfy the entire reservation so we free what 1103 * we've allocated so far. 1104 */ 1105 goto free; 1106 } 1107 /* 1108 * The surplus_list now contains _at_least_ the number of extra pages 1109 * needed to accommodate the reservation. Add the appropriate number 1110 * of pages to the hugetlb pool and free the extras back to the buddy 1111 * allocator. Commit the entire reservation here to prevent another 1112 * process from stealing the pages as they are added to the pool but 1113 * before they are reserved. 1114 */ 1115 needed += allocated; 1116 h->resv_huge_pages += delta; 1117 ret = 0; 1118 1119 /* Free the needed pages to the hugetlb pool */ 1120 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1121 if ((--needed) < 0) 1122 break; 1123 /* 1124 * This page is now managed by the hugetlb allocator and has 1125 * no users -- drop the buddy allocator's reference. 1126 */ 1127 put_page_testzero(page); 1128 VM_BUG_ON_PAGE(page_count(page), page); 1129 enqueue_huge_page(h, page); 1130 } 1131free: 1132 spin_unlock(&hugetlb_lock); 1133 1134 /* Free unnecessary surplus pages to the buddy allocator */ 1135 list_for_each_entry_safe(page, tmp, &surplus_list, lru) 1136 put_page(page); 1137 spin_lock(&hugetlb_lock); 1138 1139 return ret; 1140} 1141 1142/* 1143 * When releasing a hugetlb pool reservation, any surplus pages that were 1144 * allocated to satisfy the reservation must be explicitly freed if they were 1145 * never used. 1146 * Called with hugetlb_lock held. 1147 */ 1148static void return_unused_surplus_pages(struct hstate *h, 1149 unsigned long unused_resv_pages) 1150{ 1151 unsigned long nr_pages; 1152 1153 /* Uncommit the reservation */ 1154 h->resv_huge_pages -= unused_resv_pages; 1155 1156 /* Cannot return gigantic pages currently */ 1157 if (h->order >= MAX_ORDER) 1158 return; 1159 1160 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 1161 1162 /* 1163 * We want to release as many surplus pages as possible, spread 1164 * evenly across all nodes with memory. Iterate across these nodes 1165 * until we can no longer free unreserved surplus pages. This occurs 1166 * when the nodes with surplus pages have no free pages. 1167 * free_pool_huge_page() will balance the the freed pages across the 1168 * on-line nodes with memory and will handle the hstate accounting. 1169 */ 1170 while (nr_pages--) { 1171 if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) 1172 break; 1173 } 1174} 1175 1176/* 1177 * Determine if the huge page at addr within the vma has an associated 1178 * reservation. Where it does not we will need to logically increase 1179 * reservation and actually increase subpool usage before an allocation 1180 * can occur. Where any new reservation would be required the 1181 * reservation change is prepared, but not committed. Once the page 1182 * has been allocated from the subpool and instantiated the change should 1183 * be committed via vma_commit_reservation. No action is required on 1184 * failure. 1185 */ 1186static long vma_needs_reservation(struct hstate *h, 1187 struct vm_area_struct *vma, unsigned long addr) 1188{ 1189 struct resv_map *resv; 1190 pgoff_t idx; 1191 long chg; 1192 1193 resv = vma_resv_map(vma); 1194 if (!resv) 1195 return 1; 1196 1197 idx = vma_hugecache_offset(h, vma, addr); 1198 chg = region_chg(resv, idx, idx + 1); 1199 1200 if (vma->vm_flags & VM_MAYSHARE) 1201 return chg; 1202 else 1203 return chg < 0 ? chg : 0; 1204} 1205static void vma_commit_reservation(struct hstate *h, 1206 struct vm_area_struct *vma, unsigned long addr) 1207{ 1208 struct resv_map *resv; 1209 pgoff_t idx; 1210 1211 resv = vma_resv_map(vma); 1212 if (!resv) 1213 return; 1214 1215 idx = vma_hugecache_offset(h, vma, addr); 1216 region_add(resv, idx, idx + 1); 1217} 1218 1219static struct page *alloc_huge_page(struct vm_area_struct *vma, 1220 unsigned long addr, int avoid_reserve) 1221{ 1222 struct hugepage_subpool *spool = subpool_vma(vma); 1223 struct hstate *h = hstate_vma(vma); 1224 struct page *page; 1225 long chg; 1226 int ret, idx; 1227 struct hugetlb_cgroup *h_cg; 1228 1229 idx = hstate_index(h); 1230 /* 1231 * Processes that did not create the mapping will have no 1232 * reserves and will not have accounted against subpool 1233 * limit. Check that the subpool limit can be made before 1234 * satisfying the allocation MAP_NORESERVE mappings may also 1235 * need pages and subpool limit allocated allocated if no reserve 1236 * mapping overlaps. 1237 */ 1238 chg = vma_needs_reservation(h, vma, addr); 1239 if (chg < 0) 1240 return ERR_PTR(-ENOMEM); 1241 if (chg || avoid_reserve) 1242 if (hugepage_subpool_get_pages(spool, 1)) 1243 return ERR_PTR(-ENOSPC); 1244 1245 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); 1246 if (ret) { 1247 if (chg || avoid_reserve) 1248 hugepage_subpool_put_pages(spool, 1); 1249 return ERR_PTR(-ENOSPC); 1250 } 1251 spin_lock(&hugetlb_lock); 1252 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg); 1253 if (!page) { 1254 spin_unlock(&hugetlb_lock); 1255 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1256 if (!page) { 1257 hugetlb_cgroup_uncharge_cgroup(idx, 1258 pages_per_huge_page(h), 1259 h_cg); 1260 if (chg || avoid_reserve) 1261 hugepage_subpool_put_pages(spool, 1); 1262 return ERR_PTR(-ENOSPC); 1263 } 1264 spin_lock(&hugetlb_lock); 1265 list_move(&page->lru, &h->hugepage_activelist); 1266 /* Fall through */ 1267 } 1268 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); 1269 spin_unlock(&hugetlb_lock); 1270 1271 set_page_private(page, (unsigned long)spool); 1272 1273 vma_commit_reservation(h, vma, addr); 1274 return page; 1275} 1276 1277/* 1278 * alloc_huge_page()'s wrapper which simply returns the page if allocation 1279 * succeeds, otherwise NULL. This function is called from new_vma_page(), 1280 * where no ERR_VALUE is expected to be returned. 1281 */ 1282struct page *alloc_huge_page_noerr(struct vm_area_struct *vma, 1283 unsigned long addr, int avoid_reserve) 1284{ 1285 struct page *page = alloc_huge_page(vma, addr, avoid_reserve); 1286 if (IS_ERR(page)) 1287 page = NULL; 1288 return page; 1289} 1290 1291int __weak alloc_bootmem_huge_page(struct hstate *h) 1292{ 1293 struct huge_bootmem_page *m; 1294 int nr_nodes, node; 1295 1296 for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { 1297 void *addr; 1298 1299 addr = memblock_virt_alloc_try_nid_nopanic( 1300 huge_page_size(h), huge_page_size(h), 1301 0, BOOTMEM_ALLOC_ACCESSIBLE, node); 1302 if (addr) { 1303 /* 1304 * Use the beginning of the huge page to store the 1305 * huge_bootmem_page struct (until gather_bootmem 1306 * puts them into the mem_map). 1307 */ 1308 m = addr; 1309 goto found; 1310 } 1311 } 1312 return 0; 1313 1314found: 1315 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1316 /* Put them into a private list first because mem_map is not up yet */ 1317 list_add(&m->list, &huge_boot_pages); 1318 m->hstate = h; 1319 return 1; 1320} 1321 1322static void prep_compound_huge_page(struct page *page, int order) 1323{ 1324 if (unlikely(order > (MAX_ORDER - 1))) 1325 prep_compound_gigantic_page(page, order); 1326 else 1327 prep_compound_page(page, order); 1328} 1329 1330/* Put bootmem huge pages into the standard lists after mem_map is up */ 1331static void __init gather_bootmem_prealloc(void) 1332{ 1333 struct huge_bootmem_page *m; 1334 1335 list_for_each_entry(m, &huge_boot_pages, list) { 1336 struct hstate *h = m->hstate; 1337 struct page *page; 1338 1339#ifdef CONFIG_HIGHMEM 1340 page = pfn_to_page(m->phys >> PAGE_SHIFT); 1341 memblock_free_late(__pa(m), 1342 sizeof(struct huge_bootmem_page)); 1343#else 1344 page = virt_to_page(m); 1345#endif 1346 WARN_ON(page_count(page) != 1); 1347 prep_compound_huge_page(page, h->order); 1348 WARN_ON(PageReserved(page)); 1349 prep_new_huge_page(h, page, page_to_nid(page)); 1350 /* 1351 * If we had gigantic hugepages allocated at boot time, we need 1352 * to restore the 'stolen' pages to totalram_pages in order to 1353 * fix confusing memory reports from free(1) and another 1354 * side-effects, like CommitLimit going negative. 1355 */ 1356 if (h->order > (MAX_ORDER - 1)) 1357 adjust_managed_page_count(page, 1 << h->order); 1358 } 1359} 1360 1361static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1362{ 1363 unsigned long i; 1364 1365 for (i = 0; i < h->max_huge_pages; ++i) { 1366 if (h->order >= MAX_ORDER) { 1367 if (!alloc_bootmem_huge_page(h)) 1368 break; 1369 } else if (!alloc_fresh_huge_page(h, 1370 &node_states[N_MEMORY])) 1371 break; 1372 } 1373 h->max_huge_pages = i; 1374} 1375 1376static void __init hugetlb_init_hstates(void) 1377{ 1378 struct hstate *h; 1379 1380 for_each_hstate(h) { 1381 /* oversize hugepages were init'ed in early boot */ 1382 if (h->order < MAX_ORDER) 1383 hugetlb_hstate_alloc_pages(h); 1384 } 1385} 1386 1387static char * __init memfmt(char *buf, unsigned long n) 1388{ 1389 if (n >= (1UL << 30)) 1390 sprintf(buf, "%lu GB", n >> 30); 1391 else if (n >= (1UL << 20)) 1392 sprintf(buf, "%lu MB", n >> 20); 1393 else 1394 sprintf(buf, "%lu KB", n >> 10); 1395 return buf; 1396} 1397 1398static void __init report_hugepages(void) 1399{ 1400 struct hstate *h; 1401 1402 for_each_hstate(h) { 1403 char buf[32]; 1404 pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", 1405 memfmt(buf, huge_page_size(h)), 1406 h->free_huge_pages); 1407 } 1408} 1409 1410#ifdef CONFIG_HIGHMEM 1411static void try_to_free_low(struct hstate *h, unsigned long count, 1412 nodemask_t *nodes_allowed) 1413{ 1414 int i; 1415 1416 if (h->order >= MAX_ORDER) 1417 return; 1418 1419 for_each_node_mask(i, *nodes_allowed) { 1420 struct page *page, *next; 1421 struct list_head *freel = &h->hugepage_freelists[i]; 1422 list_for_each_entry_safe(page, next, freel, lru) { 1423 if (count >= h->nr_huge_pages) 1424 return; 1425 if (PageHighMem(page)) 1426 continue; 1427 list_del(&page->lru); 1428 update_and_free_page(h, page); 1429 h->free_huge_pages--; 1430 h->free_huge_pages_node[page_to_nid(page)]--; 1431 } 1432 } 1433} 1434#else 1435static inline void try_to_free_low(struct hstate *h, unsigned long count, 1436 nodemask_t *nodes_allowed) 1437{ 1438} 1439#endif 1440 1441/* 1442 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1443 * balanced by operating on them in a round-robin fashion. 1444 * Returns 1 if an adjustment was made. 1445 */ 1446static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1447 int delta) 1448{ 1449 int nr_nodes, node; 1450 1451 VM_BUG_ON(delta != -1 && delta != 1); 1452 1453 if (delta < 0) { 1454 for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { 1455 if (h->surplus_huge_pages_node[node]) 1456 goto found; 1457 } 1458 } else { 1459 for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { 1460 if (h->surplus_huge_pages_node[node] < 1461 h->nr_huge_pages_node[node]) 1462 goto found; 1463 } 1464 } 1465 return 0; 1466 1467found: 1468 h->surplus_huge_pages += delta; 1469 h->surplus_huge_pages_node[node] += delta; 1470 return 1; 1471} 1472 1473#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1474static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1475 nodemask_t *nodes_allowed) 1476{ 1477 unsigned long min_count, ret; 1478 1479 if (h->order >= MAX_ORDER) 1480 return h->max_huge_pages; 1481 1482 /* 1483 * Increase the pool size 1484 * First take pages out of surplus state. Then make up the 1485 * remaining difference by allocating fresh huge pages. 1486 * 1487 * We might race with alloc_buddy_huge_page() here and be unable 1488 * to convert a surplus huge page to a normal huge page. That is 1489 * not critical, though, it just means the overall size of the 1490 * pool might be one hugepage larger than it needs to be, but 1491 * within all the constraints specified by the sysctls. 1492 */ 1493 spin_lock(&hugetlb_lock); 1494 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1495 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1496 break; 1497 } 1498 1499 while (count > persistent_huge_pages(h)) { 1500 /* 1501 * If this allocation races such that we no longer need the 1502 * page, free_huge_page will handle it by freeing the page 1503 * and reducing the surplus. 1504 */ 1505 spin_unlock(&hugetlb_lock); 1506 ret = alloc_fresh_huge_page(h, nodes_allowed); 1507 spin_lock(&hugetlb_lock); 1508 if (!ret) 1509 goto out; 1510 1511 /* Bail for signals. Probably ctrl-c from user */ 1512 if (signal_pending(current)) 1513 goto out; 1514 } 1515 1516 /* 1517 * Decrease the pool size 1518 * First return free pages to the buddy allocator (being careful 1519 * to keep enough around to satisfy reservations). Then place 1520 * pages into surplus state as needed so the pool will shrink 1521 * to the desired size as pages become free. 1522 * 1523 * By placing pages into the surplus state independent of the 1524 * overcommit value, we are allowing the surplus pool size to 1525 * exceed overcommit. There are few sane options here. Since 1526 * alloc_buddy_huge_page() is checking the global counter, 1527 * though, we'll note that we're not allowed to exceed surplus 1528 * and won't grow the pool anywhere else. Not until one of the 1529 * sysctls are changed, or the surplus pages go out of use. 1530 */ 1531 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1532 min_count = max(count, min_count); 1533 try_to_free_low(h, min_count, nodes_allowed); 1534 while (min_count < persistent_huge_pages(h)) { 1535 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1536 break; 1537 } 1538 while (count < persistent_huge_pages(h)) { 1539 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1540 break; 1541 } 1542out: 1543 ret = persistent_huge_pages(h); 1544 spin_unlock(&hugetlb_lock); 1545 return ret; 1546} 1547 1548#define HSTATE_ATTR_RO(_name) \ 1549 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1550 1551#define HSTATE_ATTR(_name) \ 1552 static struct kobj_attribute _name##_attr = \ 1553 __ATTR(_name, 0644, _name##_show, _name##_store) 1554 1555static struct kobject *hugepages_kobj; 1556static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1557 1558static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1559 1560static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1561{ 1562 int i; 1563 1564 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1565 if (hstate_kobjs[i] == kobj) { 1566 if (nidp) 1567 *nidp = NUMA_NO_NODE; 1568 return &hstates[i]; 1569 } 1570 1571 return kobj_to_node_hstate(kobj, nidp); 1572} 1573 1574static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1575 struct kobj_attribute *attr, char *buf) 1576{ 1577 struct hstate *h; 1578 unsigned long nr_huge_pages; 1579 int nid; 1580 1581 h = kobj_to_hstate(kobj, &nid); 1582 if (nid == NUMA_NO_NODE) 1583 nr_huge_pages = h->nr_huge_pages; 1584 else 1585 nr_huge_pages = h->nr_huge_pages_node[nid]; 1586 1587 return sprintf(buf, "%lu\n", nr_huge_pages); 1588} 1589 1590static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1591 struct kobject *kobj, struct kobj_attribute *attr, 1592 const char *buf, size_t len) 1593{ 1594 int err; 1595 int nid; 1596 unsigned long count; 1597 struct hstate *h; 1598 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1599 1600 err = kstrtoul(buf, 10, &count); 1601 if (err) 1602 goto out; 1603 1604 h = kobj_to_hstate(kobj, &nid); 1605 if (h->order >= MAX_ORDER) { 1606 err = -EINVAL; 1607 goto out; 1608 } 1609 1610 if (nid == NUMA_NO_NODE) { 1611 /* 1612 * global hstate attribute 1613 */ 1614 if (!(obey_mempolicy && 1615 init_nodemask_of_mempolicy(nodes_allowed))) { 1616 NODEMASK_FREE(nodes_allowed); 1617 nodes_allowed = &node_states[N_MEMORY]; 1618 } 1619 } else if (nodes_allowed) { 1620 /* 1621 * per node hstate attribute: adjust count to global, 1622 * but restrict alloc/free to the specified node. 1623 */ 1624 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1625 init_nodemask_of_node(nodes_allowed, nid); 1626 } else 1627 nodes_allowed = &node_states[N_MEMORY]; 1628 1629 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1630 1631 if (nodes_allowed != &node_states[N_MEMORY]) 1632 NODEMASK_FREE(nodes_allowed); 1633 1634 return len; 1635out: 1636 NODEMASK_FREE(nodes_allowed); 1637 return err; 1638} 1639 1640static ssize_t nr_hugepages_show(struct kobject *kobj, 1641 struct kobj_attribute *attr, char *buf) 1642{ 1643 return nr_hugepages_show_common(kobj, attr, buf); 1644} 1645 1646static ssize_t nr_hugepages_store(struct kobject *kobj, 1647 struct kobj_attribute *attr, const char *buf, size_t len) 1648{ 1649 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1650} 1651HSTATE_ATTR(nr_hugepages); 1652 1653#ifdef CONFIG_NUMA 1654 1655/* 1656 * hstate attribute for optionally mempolicy-based constraint on persistent 1657 * huge page alloc/free. 1658 */ 1659static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1660 struct kobj_attribute *attr, char *buf) 1661{ 1662 return nr_hugepages_show_common(kobj, attr, buf); 1663} 1664 1665static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1666 struct kobj_attribute *attr, const char *buf, size_t len) 1667{ 1668 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1669} 1670HSTATE_ATTR(nr_hugepages_mempolicy); 1671#endif 1672 1673 1674static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1675 struct kobj_attribute *attr, char *buf) 1676{ 1677 struct hstate *h = kobj_to_hstate(kobj, NULL); 1678 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1679} 1680 1681static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1682 struct kobj_attribute *attr, const char *buf, size_t count) 1683{ 1684 int err; 1685 unsigned long input; 1686 struct hstate *h = kobj_to_hstate(kobj, NULL); 1687 1688 if (h->order >= MAX_ORDER) 1689 return -EINVAL; 1690 1691 err = kstrtoul(buf, 10, &input); 1692 if (err) 1693 return err; 1694 1695 spin_lock(&hugetlb_lock); 1696 h->nr_overcommit_huge_pages = input; 1697 spin_unlock(&hugetlb_lock); 1698 1699 return count; 1700} 1701HSTATE_ATTR(nr_overcommit_hugepages); 1702 1703static ssize_t free_hugepages_show(struct kobject *kobj, 1704 struct kobj_attribute *attr, char *buf) 1705{ 1706 struct hstate *h; 1707 unsigned long free_huge_pages; 1708 int nid; 1709 1710 h = kobj_to_hstate(kobj, &nid); 1711 if (nid == NUMA_NO_NODE) 1712 free_huge_pages = h->free_huge_pages; 1713 else 1714 free_huge_pages = h->free_huge_pages_node[nid]; 1715 1716 return sprintf(buf, "%lu\n", free_huge_pages); 1717} 1718HSTATE_ATTR_RO(free_hugepages); 1719 1720static ssize_t resv_hugepages_show(struct kobject *kobj, 1721 struct kobj_attribute *attr, char *buf) 1722{ 1723 struct hstate *h = kobj_to_hstate(kobj, NULL); 1724 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1725} 1726HSTATE_ATTR_RO(resv_hugepages); 1727 1728static ssize_t surplus_hugepages_show(struct kobject *kobj, 1729 struct kobj_attribute *attr, char *buf) 1730{ 1731 struct hstate *h; 1732 unsigned long surplus_huge_pages; 1733 int nid; 1734 1735 h = kobj_to_hstate(kobj, &nid); 1736 if (nid == NUMA_NO_NODE) 1737 surplus_huge_pages = h->surplus_huge_pages; 1738 else 1739 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1740 1741 return sprintf(buf, "%lu\n", surplus_huge_pages); 1742} 1743HSTATE_ATTR_RO(surplus_hugepages); 1744 1745static struct attribute *hstate_attrs[] = { 1746 &nr_hugepages_attr.attr, 1747 &nr_overcommit_hugepages_attr.attr, 1748 &free_hugepages_attr.attr, 1749 &resv_hugepages_attr.attr, 1750 &surplus_hugepages_attr.attr, 1751#ifdef CONFIG_NUMA 1752 &nr_hugepages_mempolicy_attr.attr, 1753#endif 1754 NULL, 1755}; 1756 1757static struct attribute_group hstate_attr_group = { 1758 .attrs = hstate_attrs, 1759}; 1760 1761static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, 1762 struct kobject **hstate_kobjs, 1763 struct attribute_group *hstate_attr_group) 1764{ 1765 int retval; 1766 int hi = hstate_index(h); 1767 1768 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1769 if (!hstate_kobjs[hi]) 1770 return -ENOMEM; 1771 1772 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1773 if (retval) 1774 kobject_put(hstate_kobjs[hi]); 1775 1776 return retval; 1777} 1778 1779static void __init hugetlb_sysfs_init(void) 1780{ 1781 struct hstate *h; 1782 int err; 1783 1784 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1785 if (!hugepages_kobj) 1786 return; 1787 1788 for_each_hstate(h) { 1789 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1790 hstate_kobjs, &hstate_attr_group); 1791 if (err) 1792 pr_err("Hugetlb: Unable to add hstate %s", h->name); 1793 } 1794} 1795 1796#ifdef CONFIG_NUMA 1797 1798/* 1799 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1800 * with node devices in node_devices[] using a parallel array. The array 1801 * index of a node device or _hstate == node id. 1802 * This is here to avoid any static dependency of the node device driver, in 1803 * the base kernel, on the hugetlb module. 1804 */ 1805struct node_hstate { 1806 struct kobject *hugepages_kobj; 1807 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1808}; 1809struct node_hstate node_hstates[MAX_NUMNODES]; 1810 1811/* 1812 * A subset of global hstate attributes for node devices 1813 */ 1814static struct attribute *per_node_hstate_attrs[] = { 1815 &nr_hugepages_attr.attr, 1816 &free_hugepages_attr.attr, 1817 &surplus_hugepages_attr.attr, 1818 NULL, 1819}; 1820 1821static struct attribute_group per_node_hstate_attr_group = { 1822 .attrs = per_node_hstate_attrs, 1823}; 1824 1825/* 1826 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. 1827 * Returns node id via non-NULL nidp. 1828 */ 1829static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1830{ 1831 int nid; 1832 1833 for (nid = 0; nid < nr_node_ids; nid++) { 1834 struct node_hstate *nhs = &node_hstates[nid]; 1835 int i; 1836 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1837 if (nhs->hstate_kobjs[i] == kobj) { 1838 if (nidp) 1839 *nidp = nid; 1840 return &hstates[i]; 1841 } 1842 } 1843 1844 BUG(); 1845 return NULL; 1846} 1847 1848/* 1849 * Unregister hstate attributes from a single node device. 1850 * No-op if no hstate attributes attached. 1851 */ 1852static void hugetlb_unregister_node(struct node *node) 1853{ 1854 struct hstate *h; 1855 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1856 1857 if (!nhs->hugepages_kobj) 1858 return; /* no hstate attributes */ 1859 1860 for_each_hstate(h) { 1861 int idx = hstate_index(h); 1862 if (nhs->hstate_kobjs[idx]) { 1863 kobject_put(nhs->hstate_kobjs[idx]); 1864 nhs->hstate_kobjs[idx] = NULL; 1865 } 1866 } 1867 1868 kobject_put(nhs->hugepages_kobj); 1869 nhs->hugepages_kobj = NULL; 1870} 1871 1872/* 1873 * hugetlb module exit: unregister hstate attributes from node devices 1874 * that have them. 1875 */ 1876static void hugetlb_unregister_all_nodes(void) 1877{ 1878 int nid; 1879 1880 /* 1881 * disable node device registrations. 1882 */ 1883 register_hugetlbfs_with_node(NULL, NULL); 1884 1885 /* 1886 * remove hstate attributes from any nodes that have them. 1887 */ 1888 for (nid = 0; nid < nr_node_ids; nid++) 1889 hugetlb_unregister_node(node_devices[nid]); 1890} 1891 1892/* 1893 * Register hstate attributes for a single node device. 1894 * No-op if attributes already registered. 1895 */ 1896static void hugetlb_register_node(struct node *node) 1897{ 1898 struct hstate *h; 1899 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1900 int err; 1901 1902 if (nhs->hugepages_kobj) 1903 return; /* already allocated */ 1904 1905 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1906 &node->dev.kobj); 1907 if (!nhs->hugepages_kobj) 1908 return; 1909 1910 for_each_hstate(h) { 1911 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1912 nhs->hstate_kobjs, 1913 &per_node_hstate_attr_group); 1914 if (err) { 1915 pr_err("Hugetlb: Unable to add hstate %s for node %d\n", 1916 h->name, node->dev.id); 1917 hugetlb_unregister_node(node); 1918 break; 1919 } 1920 } 1921} 1922 1923/* 1924 * hugetlb init time: register hstate attributes for all registered node 1925 * devices of nodes that have memory. All on-line nodes should have 1926 * registered their associated device by this time. 1927 */ 1928static void hugetlb_register_all_nodes(void) 1929{ 1930 int nid; 1931 1932 for_each_node_state(nid, N_MEMORY) { 1933 struct node *node = node_devices[nid]; 1934 if (node->dev.id == nid) 1935 hugetlb_register_node(node); 1936 } 1937 1938 /* 1939 * Let the node device driver know we're here so it can 1940 * [un]register hstate attributes on node hotplug. 1941 */ 1942 register_hugetlbfs_with_node(hugetlb_register_node, 1943 hugetlb_unregister_node); 1944} 1945#else /* !CONFIG_NUMA */ 1946 1947static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1948{ 1949 BUG(); 1950 if (nidp) 1951 *nidp = -1; 1952 return NULL; 1953} 1954 1955static void hugetlb_unregister_all_nodes(void) { } 1956 1957static void hugetlb_register_all_nodes(void) { } 1958 1959#endif 1960 1961static void __exit hugetlb_exit(void) 1962{ 1963 struct hstate *h; 1964 1965 hugetlb_unregister_all_nodes(); 1966 1967 for_each_hstate(h) { 1968 kobject_put(hstate_kobjs[hstate_index(h)]); 1969 } 1970 1971 kobject_put(hugepages_kobj); 1972 kfree(htlb_fault_mutex_table); 1973} 1974module_exit(hugetlb_exit); 1975 1976static int __init hugetlb_init(void) 1977{ 1978 int i; 1979 1980 /* Some platform decide whether they support huge pages at boot 1981 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1982 * there is no such support 1983 */ 1984 if (HPAGE_SHIFT == 0) 1985 return 0; 1986 1987 if (!size_to_hstate(default_hstate_size)) { 1988 default_hstate_size = HPAGE_SIZE; 1989 if (!size_to_hstate(default_hstate_size)) 1990 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1991 } 1992 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); 1993 if (default_hstate_max_huge_pages) 1994 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1995 1996 hugetlb_init_hstates(); 1997 gather_bootmem_prealloc(); 1998 report_hugepages(); 1999 2000 hugetlb_sysfs_init(); 2001 hugetlb_register_all_nodes(); 2002 hugetlb_cgroup_file_init(); 2003 2004#ifdef CONFIG_SMP 2005 num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); 2006#else 2007 num_fault_mutexes = 1; 2008#endif 2009 htlb_fault_mutex_table = 2010 kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL); 2011 BUG_ON(!htlb_fault_mutex_table); 2012 2013 for (i = 0; i < num_fault_mutexes; i++) 2014 mutex_init(&htlb_fault_mutex_table[i]); 2015 return 0; 2016} 2017module_init(hugetlb_init); 2018 2019/* Should be called on processing a hugepagesz=... option */ 2020void __init hugetlb_add_hstate(unsigned order) 2021{ 2022 struct hstate *h; 2023 unsigned long i; 2024 2025 if (size_to_hstate(PAGE_SIZE << order)) { 2026 pr_warning("hugepagesz= specified twice, ignoring\n"); 2027 return; 2028 } 2029 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); 2030 BUG_ON(order == 0); 2031 h = &hstates[hugetlb_max_hstate++]; 2032 h->order = order; 2033 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 2034 h->nr_huge_pages = 0; 2035 h->free_huge_pages = 0; 2036 for (i = 0; i < MAX_NUMNODES; ++i) 2037 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 2038 INIT_LIST_HEAD(&h->hugepage_activelist); 2039 h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); 2040 h->next_nid_to_free = first_node(node_states[N_MEMORY]); 2041 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 2042 huge_page_size(h)/1024); 2043 2044 parsed_hstate = h; 2045} 2046 2047static int __init hugetlb_nrpages_setup(char *s) 2048{ 2049 unsigned long *mhp; 2050 static unsigned long *last_mhp; 2051 2052 /* 2053 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, 2054 * so this hugepages= parameter goes to the "default hstate". 2055 */ 2056 if (!hugetlb_max_hstate) 2057 mhp = &default_hstate_max_huge_pages; 2058 else 2059 mhp = &parsed_hstate->max_huge_pages; 2060 2061 if (mhp == last_mhp) { 2062 pr_warning("hugepages= specified twice without " 2063 "interleaving hugepagesz=, ignoring\n"); 2064 return 1; 2065 } 2066 2067 if (sscanf(s, "%lu", mhp) <= 0) 2068 *mhp = 0; 2069 2070 /* 2071 * Global state is always initialized later in hugetlb_init. 2072 * But we need to allocate >= MAX_ORDER hstates here early to still 2073 * use the bootmem allocator. 2074 */ 2075 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) 2076 hugetlb_hstate_alloc_pages(parsed_hstate); 2077 2078 last_mhp = mhp; 2079 2080 return 1; 2081} 2082__setup("hugepages=", hugetlb_nrpages_setup); 2083 2084static int __init hugetlb_default_setup(char *s) 2085{ 2086 default_hstate_size = memparse(s, &s); 2087 return 1; 2088} 2089__setup("default_hugepagesz=", hugetlb_default_setup); 2090 2091static unsigned int cpuset_mems_nr(unsigned int *array) 2092{ 2093 int node; 2094 unsigned int nr = 0; 2095 2096 for_each_node_mask(node, cpuset_current_mems_allowed) 2097 nr += array[node]; 2098 2099 return nr; 2100} 2101 2102#ifdef CONFIG_SYSCTL 2103static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 2104 struct ctl_table *table, int write, 2105 void __user *buffer, size_t *length, loff_t *ppos) 2106{ 2107 struct hstate *h = &default_hstate; 2108 unsigned long tmp; 2109 int ret; 2110 2111 tmp = h->max_huge_pages; 2112 2113 if (write && h->order >= MAX_ORDER) 2114 return -EINVAL; 2115 2116 table->data = &tmp; 2117 table->maxlen = sizeof(unsigned long); 2118 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2119 if (ret) 2120 goto out; 2121 2122 if (write) { 2123 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 2124 GFP_KERNEL | __GFP_NORETRY); 2125 if (!(obey_mempolicy && 2126 init_nodemask_of_mempolicy(nodes_allowed))) { 2127 NODEMASK_FREE(nodes_allowed); 2128 nodes_allowed = &node_states[N_MEMORY]; 2129 } 2130 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 2131 2132 if (nodes_allowed != &node_states[N_MEMORY]) 2133 NODEMASK_FREE(nodes_allowed); 2134 } 2135out: 2136 return ret; 2137} 2138 2139int hugetlb_sysctl_handler(struct ctl_table *table, int write, 2140 void __user *buffer, size_t *length, loff_t *ppos) 2141{ 2142 2143 return hugetlb_sysctl_handler_common(false, table, write, 2144 buffer, length, ppos); 2145} 2146 2147#ifdef CONFIG_NUMA 2148int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 2149 void __user *buffer, size_t *length, loff_t *ppos) 2150{ 2151 return hugetlb_sysctl_handler_common(true, table, write, 2152 buffer, length, ppos); 2153} 2154#endif /* CONFIG_NUMA */ 2155 2156int hugetlb_overcommit_handler(struct ctl_table *table, int write, 2157 void __user *buffer, 2158 size_t *length, loff_t *ppos) 2159{ 2160 struct hstate *h = &default_hstate; 2161 unsigned long tmp; 2162 int ret; 2163 2164 tmp = h->nr_overcommit_huge_pages; 2165 2166 if (write && h->order >= MAX_ORDER) 2167 return -EINVAL; 2168 2169 table->data = &tmp; 2170 table->maxlen = sizeof(unsigned long); 2171 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2172 if (ret) 2173 goto out; 2174 2175 if (write) { 2176 spin_lock(&hugetlb_lock); 2177 h->nr_overcommit_huge_pages = tmp; 2178 spin_unlock(&hugetlb_lock); 2179 } 2180out: 2181 return ret; 2182} 2183 2184#endif /* CONFIG_SYSCTL */ 2185 2186void hugetlb_report_meminfo(struct seq_file *m) 2187{ 2188 struct hstate *h = &default_hstate; 2189 seq_printf(m, 2190 "HugePages_Total: %5lu\n" 2191 "HugePages_Free: %5lu\n" 2192 "HugePages_Rsvd: %5lu\n" 2193 "HugePages_Surp: %5lu\n" 2194 "Hugepagesize: %8lu kB\n", 2195 h->nr_huge_pages, 2196 h->free_huge_pages, 2197 h->resv_huge_pages, 2198 h->surplus_huge_pages, 2199 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2200} 2201 2202int hugetlb_report_node_meminfo(int nid, char *buf) 2203{ 2204 struct hstate *h = &default_hstate; 2205 return sprintf(buf, 2206 "Node %d HugePages_Total: %5u\n" 2207 "Node %d HugePages_Free: %5u\n" 2208 "Node %d HugePages_Surp: %5u\n", 2209 nid, h->nr_huge_pages_node[nid], 2210 nid, h->free_huge_pages_node[nid], 2211 nid, h->surplus_huge_pages_node[nid]); 2212} 2213 2214void hugetlb_show_meminfo(void) 2215{ 2216 struct hstate *h; 2217 int nid; 2218 2219 for_each_node_state(nid, N_MEMORY) 2220 for_each_hstate(h) 2221 pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", 2222 nid, 2223 h->nr_huge_pages_node[nid], 2224 h->free_huge_pages_node[nid], 2225 h->surplus_huge_pages_node[nid], 2226 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2227} 2228 2229/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 2230unsigned long hugetlb_total_pages(void) 2231{ 2232 struct hstate *h; 2233 unsigned long nr_total_pages = 0; 2234 2235 for_each_hstate(h) 2236 nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); 2237 return nr_total_pages; 2238} 2239 2240static int hugetlb_acct_memory(struct hstate *h, long delta) 2241{ 2242 int ret = -ENOMEM; 2243 2244 spin_lock(&hugetlb_lock); 2245 /* 2246 * When cpuset is configured, it breaks the strict hugetlb page 2247 * reservation as the accounting is done on a global variable. Such 2248 * reservation is completely rubbish in the presence of cpuset because 2249 * the reservation is not checked against page availability for the 2250 * current cpuset. Application can still potentially OOM'ed by kernel 2251 * with lack of free htlb page in cpuset that the task is in. 2252 * Attempt to enforce strict accounting with cpuset is almost 2253 * impossible (or too ugly) because cpuset is too fluid that 2254 * task or memory node can be dynamically moved between cpusets. 2255 * 2256 * The change of semantics for shared hugetlb mapping with cpuset is 2257 * undesirable. However, in order to preserve some of the semantics, 2258 * we fall back to check against current free page availability as 2259 * a best attempt and hopefully to minimize the impact of changing 2260 * semantics that cpuset has. 2261 */ 2262 if (delta > 0) { 2263 if (gather_surplus_pages(h, delta) < 0) 2264 goto out; 2265 2266 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 2267 return_unused_surplus_pages(h, delta); 2268 goto out; 2269 } 2270 } 2271 2272 ret = 0; 2273 if (delta < 0) 2274 return_unused_surplus_pages(h, (unsigned long) -delta); 2275 2276out: 2277 spin_unlock(&hugetlb_lock); 2278 return ret; 2279} 2280 2281static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2282{ 2283 struct resv_map *resv = vma_resv_map(vma); 2284 2285 /* 2286 * This new VMA should share its siblings reservation map if present. 2287 * The VMA will only ever have a valid reservation map pointer where 2288 * it is being copied for another still existing VMA. As that VMA 2289 * has a reference to the reservation map it cannot disappear until 2290 * after this open call completes. It is therefore safe to take a 2291 * new reference here without additional locking. 2292 */ 2293 if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 2294 kref_get(&resv->refs); 2295} 2296 2297static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2298{ 2299 struct hstate *h = hstate_vma(vma); 2300 struct resv_map *resv = vma_resv_map(vma); 2301 struct hugepage_subpool *spool = subpool_vma(vma); 2302 unsigned long reserve, start, end; 2303 2304 if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 2305 return; 2306 2307 start = vma_hugecache_offset(h, vma, vma->vm_start); 2308 end = vma_hugecache_offset(h, vma, vma->vm_end); 2309 2310 reserve = (end - start) - region_count(resv, start, end); 2311 2312 kref_put(&resv->refs, resv_map_release); 2313 2314 if (reserve) { 2315 hugetlb_acct_memory(h, -reserve); 2316 hugepage_subpool_put_pages(spool, reserve); 2317 } 2318} 2319 2320/* 2321 * We cannot handle pagefaults against hugetlb pages at all. They cause 2322 * handle_mm_fault() to try to instantiate regular-sized pages in the 2323 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2324 * this far. 2325 */ 2326static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2327{ 2328 BUG(); 2329 return 0; 2330} 2331 2332const struct vm_operations_struct hugetlb_vm_ops = { 2333 .fault = hugetlb_vm_op_fault, 2334 .open = hugetlb_vm_op_open, 2335 .close = hugetlb_vm_op_close, 2336}; 2337 2338static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2339 int writable) 2340{ 2341 pte_t entry; 2342 2343 if (writable) { 2344 entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, 2345 vma->vm_page_prot))); 2346 } else { 2347 entry = huge_pte_wrprotect(mk_huge_pte(page, 2348 vma->vm_page_prot)); 2349 } 2350 entry = pte_mkyoung(entry); 2351 entry = pte_mkhuge(entry); 2352 entry = arch_make_huge_pte(entry, vma, page, writable); 2353 2354 return entry; 2355} 2356 2357static void set_huge_ptep_writable(struct vm_area_struct *vma, 2358 unsigned long address, pte_t *ptep) 2359{ 2360 pte_t entry; 2361 2362 entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); 2363 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) 2364 update_mmu_cache(vma, address, ptep); 2365} 2366 2367 2368int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2369 struct vm_area_struct *vma) 2370{ 2371 pte_t *src_pte, *dst_pte, entry; 2372 struct page *ptepage; 2373 unsigned long addr; 2374 int cow; 2375 struct hstate *h = hstate_vma(vma); 2376 unsigned long sz = huge_page_size(h); 2377 unsigned long mmun_start; /* For mmu_notifiers */ 2378 unsigned long mmun_end; /* For mmu_notifiers */ 2379 int ret = 0; 2380 2381 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2382 2383 mmun_start = vma->vm_start; 2384 mmun_end = vma->vm_end; 2385 if (cow) 2386 mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); 2387 2388 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2389 spinlock_t *src_ptl, *dst_ptl; 2390 src_pte = huge_pte_offset(src, addr); 2391 if (!src_pte) 2392 continue; 2393 dst_pte = huge_pte_alloc(dst, addr, sz); 2394 if (!dst_pte) { 2395 ret = -ENOMEM; 2396 break; 2397 } 2398 2399 /* If the pagetables are shared don't copy or take references */ 2400 if (dst_pte == src_pte) 2401 continue; 2402 2403 dst_ptl = huge_pte_lock(h, dst, dst_pte); 2404 src_ptl = huge_pte_lockptr(h, src, src_pte); 2405 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 2406 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2407 if (cow) 2408 huge_ptep_set_wrprotect(src, addr, src_pte); 2409 entry = huge_ptep_get(src_pte); 2410 ptepage = pte_page(entry); 2411 get_page(ptepage); 2412 page_dup_rmap(ptepage); 2413 set_huge_pte_at(dst, addr, dst_pte, entry); 2414 } 2415 spin_unlock(src_ptl); 2416 spin_unlock(dst_ptl); 2417 } 2418 2419 if (cow) 2420 mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); 2421 2422 return ret; 2423} 2424 2425static int is_hugetlb_entry_migration(pte_t pte) 2426{ 2427 swp_entry_t swp; 2428 2429 if (huge_pte_none(pte) || pte_present(pte)) 2430 return 0; 2431 swp = pte_to_swp_entry(pte); 2432 if (non_swap_entry(swp) && is_migration_entry(swp)) 2433 return 1; 2434 else 2435 return 0; 2436} 2437 2438static int is_hugetlb_entry_hwpoisoned(pte_t pte) 2439{ 2440 swp_entry_t swp; 2441 2442 if (huge_pte_none(pte) || pte_present(pte)) 2443 return 0; 2444 swp = pte_to_swp_entry(pte); 2445 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) 2446 return 1; 2447 else 2448 return 0; 2449} 2450 2451void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 2452 unsigned long start, unsigned long end, 2453 struct page *ref_page) 2454{ 2455 int force_flush = 0; 2456 struct mm_struct *mm = vma->vm_mm; 2457 unsigned long address; 2458 pte_t *ptep; 2459 pte_t pte; 2460 spinlock_t *ptl; 2461 struct page *page; 2462 struct hstate *h = hstate_vma(vma); 2463 unsigned long sz = huge_page_size(h); 2464 const unsigned long mmun_start = start; /* For mmu_notifiers */ 2465 const unsigned long mmun_end = end; /* For mmu_notifiers */ 2466 2467 WARN_ON(!is_vm_hugetlb_page(vma)); 2468 BUG_ON(start & ~huge_page_mask(h)); 2469 BUG_ON(end & ~huge_page_mask(h)); 2470 2471 tlb_start_vma(tlb, vma); 2472 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2473again: 2474 for (address = start; address < end; address += sz) { 2475 ptep = huge_pte_offset(mm, address); 2476 if (!ptep) 2477 continue; 2478 2479 ptl = huge_pte_lock(h, mm, ptep); 2480 if (huge_pmd_unshare(mm, &address, ptep)) 2481 goto unlock; 2482 2483 pte = huge_ptep_get(ptep); 2484 if (huge_pte_none(pte)) 2485 goto unlock; 2486 2487 /* 2488 * HWPoisoned hugepage is already unmapped and dropped reference 2489 */ 2490 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { 2491 huge_pte_clear(mm, address, ptep); 2492 goto unlock; 2493 } 2494 2495 page = pte_page(pte); 2496 /* 2497 * If a reference page is supplied, it is because a specific 2498 * page is being unmapped, not a range. Ensure the page we 2499 * are about to unmap is the actual page of interest. 2500 */ 2501 if (ref_page) { 2502 if (page != ref_page) 2503 goto unlock; 2504 2505 /* 2506 * Mark the VMA as having unmapped its page so that 2507 * future faults in this VMA will fail rather than 2508 * looking like data was lost 2509 */ 2510 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2511 } 2512 2513 pte = huge_ptep_get_and_clear(mm, address, ptep); 2514 tlb_remove_tlb_entry(tlb, ptep, address); 2515 if (huge_pte_dirty(pte)) 2516 set_page_dirty(page); 2517 2518 page_remove_rmap(page); 2519 force_flush = !__tlb_remove_page(tlb, page); 2520 if (force_flush) { 2521 spin_unlock(ptl); 2522 break; 2523 } 2524 /* Bail out after unmapping reference page if supplied */ 2525 if (ref_page) { 2526 spin_unlock(ptl); 2527 break; 2528 } 2529unlock: 2530 spin_unlock(ptl); 2531 } 2532 /* 2533 * mmu_gather ran out of room to batch pages, we break out of 2534 * the PTE lock to avoid doing the potential expensive TLB invalidate 2535 * and page-free while holding it. 2536 */ 2537 if (force_flush) { 2538 force_flush = 0; 2539 tlb_flush_mmu(tlb); 2540 if (address < end && !ref_page) 2541 goto again; 2542 } 2543 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2544 tlb_end_vma(tlb, vma); 2545} 2546 2547void __unmap_hugepage_range_final(struct mmu_gather *tlb, 2548 struct vm_area_struct *vma, unsigned long start, 2549 unsigned long end, struct page *ref_page) 2550{ 2551 __unmap_hugepage_range(tlb, vma, start, end, ref_page); 2552 2553 /* 2554 * Clear this flag so that x86's huge_pmd_share page_table_shareable 2555 * test will fail on a vma being torn down, and not grab a page table 2556 * on its way out. We're lucky that the flag has such an appropriate 2557 * name, and can in fact be safely cleared here. We could clear it 2558 * before the __unmap_hugepage_range above, but all that's necessary 2559 * is to clear it before releasing the i_mmap_mutex. This works 2560 * because in the context this is called, the VMA is about to be 2561 * destroyed and the i_mmap_mutex is held. 2562 */ 2563 vma->vm_flags &= ~VM_MAYSHARE; 2564} 2565 2566void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2567 unsigned long end, struct page *ref_page) 2568{ 2569 struct mm_struct *mm; 2570 struct mmu_gather tlb; 2571 2572 mm = vma->vm_mm; 2573 2574 tlb_gather_mmu(&tlb, mm, start, end); 2575 __unmap_hugepage_range(&tlb, vma, start, end, ref_page); 2576 tlb_finish_mmu(&tlb, start, end); 2577} 2578 2579/* 2580 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2581 * mappping it owns the reserve page for. The intention is to unmap the page 2582 * from other VMAs and let the children be SIGKILLed if they are faulting the 2583 * same region. 2584 */ 2585static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2586 struct page *page, unsigned long address) 2587{ 2588 struct hstate *h = hstate_vma(vma); 2589 struct vm_area_struct *iter_vma; 2590 struct address_space *mapping; 2591 pgoff_t pgoff; 2592 2593 /* 2594 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2595 * from page cache lookup which is in HPAGE_SIZE units. 2596 */ 2597 address = address & huge_page_mask(h); 2598 pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + 2599 vma->vm_pgoff; 2600 mapping = file_inode(vma->vm_file)->i_mapping; 2601 2602 /* 2603 * Take the mapping lock for the duration of the table walk. As 2604 * this mapping should be shared between all the VMAs, 2605 * __unmap_hugepage_range() is called as the lock is already held 2606 */ 2607 mutex_lock(&mapping->i_mmap_mutex); 2608 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { 2609 /* Do not unmap the current VMA */ 2610 if (iter_vma == vma) 2611 continue; 2612 2613 /* 2614 * Unmap the page from other VMAs without their own reserves. 2615 * They get marked to be SIGKILLed if they fault in these 2616 * areas. This is because a future no-page fault on this VMA 2617 * could insert a zeroed page instead of the data existing 2618 * from the time of fork. This would look like data corruption 2619 */ 2620 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2621 unmap_hugepage_range(iter_vma, address, 2622 address + huge_page_size(h), page); 2623 } 2624 mutex_unlock(&mapping->i_mmap_mutex); 2625 2626 return 1; 2627} 2628 2629/* 2630 * Hugetlb_cow() should be called with page lock of the original hugepage held. 2631 * Called with hugetlb_instantiation_mutex held and pte_page locked so we 2632 * cannot race with other handlers or page migration. 2633 * Keep the pte_same checks anyway to make transition from the mutex easier. 2634 */ 2635static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2636 unsigned long address, pte_t *ptep, pte_t pte, 2637 struct page *pagecache_page, spinlock_t *ptl) 2638{ 2639 struct hstate *h = hstate_vma(vma); 2640 struct page *old_page, *new_page; 2641 int outside_reserve = 0; 2642 unsigned long mmun_start; /* For mmu_notifiers */ 2643 unsigned long mmun_end; /* For mmu_notifiers */ 2644 2645 old_page = pte_page(pte); 2646 2647retry_avoidcopy: 2648 /* If no-one else is actually using this page, avoid the copy 2649 * and just make the page writable */ 2650 if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { 2651 page_move_anon_rmap(old_page, vma, address); 2652 set_huge_ptep_writable(vma, address, ptep); 2653 return 0; 2654 } 2655 2656 /* 2657 * If the process that created a MAP_PRIVATE mapping is about to 2658 * perform a COW due to a shared page count, attempt to satisfy 2659 * the allocation without using the existing reserves. The pagecache 2660 * page is used to determine if the reserve at this address was 2661 * consumed or not. If reserves were used, a partial faulted mapping 2662 * at the time of fork() could consume its reserves on COW instead 2663 * of the full address range. 2664 */ 2665 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2666 old_page != pagecache_page) 2667 outside_reserve = 1; 2668 2669 page_cache_get(old_page); 2670 2671 /* Drop page table lock as buddy allocator may be called */ 2672 spin_unlock(ptl); 2673 new_page = alloc_huge_page(vma, address, outside_reserve); 2674 2675 if (IS_ERR(new_page)) { 2676 long err = PTR_ERR(new_page); 2677 page_cache_release(old_page); 2678 2679 /* 2680 * If a process owning a MAP_PRIVATE mapping fails to COW, 2681 * it is due to references held by a child and an insufficient 2682 * huge page pool. To guarantee the original mappers 2683 * reliability, unmap the page from child processes. The child 2684 * may get SIGKILLed if it later faults. 2685 */ 2686 if (outside_reserve) { 2687 BUG_ON(huge_pte_none(pte)); 2688 if (unmap_ref_private(mm, vma, old_page, address)) { 2689 BUG_ON(huge_pte_none(pte)); 2690 spin_lock(ptl); 2691 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2692 if (likely(pte_same(huge_ptep_get(ptep), pte))) 2693 goto retry_avoidcopy; 2694 /* 2695 * race occurs while re-acquiring page table 2696 * lock, and our job is done. 2697 */ 2698 return 0; 2699 } 2700 WARN_ON_ONCE(1); 2701 } 2702 2703 /* Caller expects lock to be held */ 2704 spin_lock(ptl); 2705 if (err == -ENOMEM) 2706 return VM_FAULT_OOM; 2707 else 2708 return VM_FAULT_SIGBUS; 2709 } 2710 2711 /* 2712 * When the original hugepage is shared one, it does not have 2713 * anon_vma prepared. 2714 */ 2715 if (unlikely(anon_vma_prepare(vma))) { 2716 page_cache_release(new_page); 2717 page_cache_release(old_page); 2718 /* Caller expects lock to be held */ 2719 spin_lock(ptl); 2720 return VM_FAULT_OOM; 2721 } 2722 2723 copy_user_huge_page(new_page, old_page, address, vma, 2724 pages_per_huge_page(h)); 2725 __SetPageUptodate(new_page); 2726 2727 mmun_start = address & huge_page_mask(h); 2728 mmun_end = mmun_start + huge_page_size(h); 2729 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); 2730 /* 2731 * Retake the page table lock to check for racing updates 2732 * before the page tables are altered 2733 */ 2734 spin_lock(ptl); 2735 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2736 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2737 ClearPagePrivate(new_page); 2738 2739 /* Break COW */ 2740 huge_ptep_clear_flush(vma, address, ptep); 2741 set_huge_pte_at(mm, address, ptep, 2742 make_huge_pte(vma, new_page, 1)); 2743 page_remove_rmap(old_page); 2744 hugepage_add_new_anon_rmap(new_page, vma, address); 2745 /* Make the old page be freed below */ 2746 new_page = old_page; 2747 } 2748 spin_unlock(ptl); 2749 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); 2750 page_cache_release(new_page); 2751 page_cache_release(old_page); 2752 2753 /* Caller expects lock to be held */ 2754 spin_lock(ptl); 2755 return 0; 2756} 2757 2758/* Return the pagecache page at a given address within a VMA */ 2759static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2760 struct vm_area_struct *vma, unsigned long address) 2761{ 2762 struct address_space *mapping; 2763 pgoff_t idx; 2764 2765 mapping = vma->vm_file->f_mapping; 2766 idx = vma_hugecache_offset(h, vma, address); 2767 2768 return find_lock_page(mapping, idx); 2769} 2770 2771/* 2772 * Return whether there is a pagecache page to back given address within VMA. 2773 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2774 */ 2775static bool hugetlbfs_pagecache_present(struct hstate *h, 2776 struct vm_area_struct *vma, unsigned long address) 2777{ 2778 struct address_space *mapping; 2779 pgoff_t idx; 2780 struct page *page; 2781 2782 mapping = vma->vm_file->f_mapping; 2783 idx = vma_hugecache_offset(h, vma, address); 2784 2785 page = find_get_page(mapping, idx); 2786 if (page) 2787 put_page(page); 2788 return page != NULL; 2789} 2790 2791static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2792 struct address_space *mapping, pgoff_t idx, 2793 unsigned long address, pte_t *ptep, unsigned int flags) 2794{ 2795 struct hstate *h = hstate_vma(vma); 2796 int ret = VM_FAULT_SIGBUS; 2797 int anon_rmap = 0; 2798 unsigned long size; 2799 struct page *page; 2800 pte_t new_pte; 2801 spinlock_t *ptl; 2802 2803 /* 2804 * Currently, we are forced to kill the process in the event the 2805 * original mapper has unmapped pages from the child due to a failed 2806 * COW. Warn that such a situation has occurred as it may not be obvious 2807 */ 2808 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2809 pr_warning("PID %d killed due to inadequate hugepage pool\n", 2810 current->pid); 2811 return ret; 2812 } 2813 2814 /* 2815 * Use page lock to guard against racing truncation 2816 * before we get page_table_lock. 2817 */ 2818retry: 2819 page = find_lock_page(mapping, idx); 2820 if (!page) { 2821 size = i_size_read(mapping->host) >> huge_page_shift(h); 2822 if (idx >= size) 2823 goto out; 2824 page = alloc_huge_page(vma, address, 0); 2825 if (IS_ERR(page)) { 2826 ret = PTR_ERR(page); 2827 if (ret == -ENOMEM) 2828 ret = VM_FAULT_OOM; 2829 else 2830 ret = VM_FAULT_SIGBUS; 2831 goto out; 2832 } 2833 clear_huge_page(page, address, pages_per_huge_page(h)); 2834 __SetPageUptodate(page); 2835 2836 if (vma->vm_flags & VM_MAYSHARE) { 2837 int err; 2838 struct inode *inode = mapping->host; 2839 2840 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2841 if (err) { 2842 put_page(page); 2843 if (err == -EEXIST) 2844 goto retry; 2845 goto out; 2846 } 2847 ClearPagePrivate(page); 2848 2849 spin_lock(&inode->i_lock); 2850 inode->i_blocks += blocks_per_huge_page(h); 2851 spin_unlock(&inode->i_lock); 2852 } else { 2853 lock_page(page); 2854 if (unlikely(anon_vma_prepare(vma))) { 2855 ret = VM_FAULT_OOM; 2856 goto backout_unlocked; 2857 } 2858 anon_rmap = 1; 2859 } 2860 } else { 2861 /* 2862 * If memory error occurs between mmap() and fault, some process 2863 * don't have hwpoisoned swap entry for errored virtual address. 2864 * So we need to block hugepage fault by PG_hwpoison bit check. 2865 */ 2866 if (unlikely(PageHWPoison(page))) { 2867 ret = VM_FAULT_HWPOISON | 2868 VM_FAULT_SET_HINDEX(hstate_index(h)); 2869 goto backout_unlocked; 2870 } 2871 } 2872 2873 /* 2874 * If we are going to COW a private mapping later, we examine the 2875 * pending reservations for this page now. This will ensure that 2876 * any allocations necessary to record that reservation occur outside 2877 * the spinlock. 2878 */ 2879 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2880 if (vma_needs_reservation(h, vma, address) < 0) { 2881 ret = VM_FAULT_OOM; 2882 goto backout_unlocked; 2883 } 2884 2885 ptl = huge_pte_lockptr(h, mm, ptep); 2886 spin_lock(ptl); 2887 size = i_size_read(mapping->host) >> huge_page_shift(h); 2888 if (idx >= size) 2889 goto backout; 2890 2891 ret = 0; 2892 if (!huge_pte_none(huge_ptep_get(ptep))) 2893 goto backout; 2894 2895 if (anon_rmap) { 2896 ClearPagePrivate(page); 2897 hugepage_add_new_anon_rmap(page, vma, address); 2898 } 2899 else 2900 page_dup_rmap(page); 2901 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2902 && (vma->vm_flags & VM_SHARED))); 2903 set_huge_pte_at(mm, address, ptep, new_pte); 2904 2905 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2906 /* Optimization, do the COW without a second fault */ 2907 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl); 2908 } 2909 2910 spin_unlock(ptl); 2911 unlock_page(page); 2912out: 2913 return ret; 2914 2915backout: 2916 spin_unlock(ptl); 2917backout_unlocked: 2918 unlock_page(page); 2919 put_page(page); 2920 goto out; 2921} 2922 2923#ifdef CONFIG_SMP 2924static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, 2925 struct vm_area_struct *vma, 2926 struct address_space *mapping, 2927 pgoff_t idx, unsigned long address) 2928{ 2929 unsigned long key[2]; 2930 u32 hash; 2931 2932 if (vma->vm_flags & VM_SHARED) { 2933 key[0] = (unsigned long) mapping; 2934 key[1] = idx; 2935 } else { 2936 key[0] = (unsigned long) mm; 2937 key[1] = address >> huge_page_shift(h); 2938 } 2939 2940 hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0); 2941 2942 return hash & (num_fault_mutexes - 1); 2943} 2944#else 2945/* 2946 * For uniprocesor systems we always use a single mutex, so just 2947 * return 0 and avoid the hashing overhead. 2948 */ 2949static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, 2950 struct vm_area_struct *vma, 2951 struct address_space *mapping, 2952 pgoff_t idx, unsigned long address) 2953{ 2954 return 0; 2955} 2956#endif 2957 2958int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2959 unsigned long address, unsigned int flags) 2960{ 2961 pte_t *ptep, entry; 2962 spinlock_t *ptl; 2963 int ret; 2964 u32 hash; 2965 pgoff_t idx; 2966 struct page *page = NULL; 2967 struct page *pagecache_page = NULL; 2968 struct hstate *h = hstate_vma(vma); 2969 struct address_space *mapping; 2970 2971 address &= huge_page_mask(h); 2972 2973 ptep = huge_pte_offset(mm, address); 2974 if (ptep) { 2975 entry = huge_ptep_get(ptep); 2976 if (unlikely(is_hugetlb_entry_migration(entry))) { 2977 migration_entry_wait_huge(vma, mm, ptep); 2978 return 0; 2979 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) 2980 return VM_FAULT_HWPOISON_LARGE | 2981 VM_FAULT_SET_HINDEX(hstate_index(h)); 2982 } 2983 2984 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2985 if (!ptep) 2986 return VM_FAULT_OOM; 2987 2988 mapping = vma->vm_file->f_mapping; 2989 idx = vma_hugecache_offset(h, vma, address); 2990 2991 /* 2992 * Serialize hugepage allocation and instantiation, so that we don't 2993 * get spurious allocation failures if two CPUs race to instantiate 2994 * the same page in the page cache. 2995 */ 2996 hash = fault_mutex_hash(h, mm, vma, mapping, idx, address); 2997 mutex_lock(&htlb_fault_mutex_table[hash]); 2998 2999 entry = huge_ptep_get(ptep); 3000 if (huge_pte_none(entry)) { 3001 ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags); 3002 goto out_mutex; 3003 } 3004 3005 ret = 0; 3006 3007 /* 3008 * If we are going to COW the mapping later, we examine the pending 3009 * reservations for this page now. This will ensure that any 3010 * allocations necessary to record that reservation occur outside the 3011 * spinlock. For private mappings, we also lookup the pagecache 3012 * page now as it is used to determine if a reservation has been 3013 * consumed. 3014 */ 3015 if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { 3016 if (vma_needs_reservation(h, vma, address) < 0) { 3017 ret = VM_FAULT_OOM; 3018 goto out_mutex; 3019 } 3020 3021 if (!(vma->vm_flags & VM_MAYSHARE)) 3022 pagecache_page = hugetlbfs_pagecache_page(h, 3023 vma, address); 3024 } 3025 3026 /* 3027 * hugetlb_cow() requires page locks of pte_page(entry) and 3028 * pagecache_page, so here we need take the former one 3029 * when page != pagecache_page or !pagecache_page. 3030 * Note that locking order is always pagecache_page -> page, 3031 * so no worry about deadlock. 3032 */ 3033 page = pte_page(entry); 3034 get_page(page); 3035 if (page != pagecache_page) 3036 lock_page(page); 3037 3038 ptl = huge_pte_lockptr(h, mm, ptep); 3039 spin_lock(ptl); 3040 /* Check for a racing update before calling hugetlb_cow */ 3041 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 3042 goto out_ptl; 3043 3044 3045 if (flags & FAULT_FLAG_WRITE) { 3046 if (!huge_pte_write(entry)) { 3047 ret = hugetlb_cow(mm, vma, address, ptep, entry, 3048 pagecache_page, ptl); 3049 goto out_ptl; 3050 } 3051 entry = huge_pte_mkdirty(entry); 3052 } 3053 entry = pte_mkyoung(entry); 3054 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 3055 flags & FAULT_FLAG_WRITE)) 3056 update_mmu_cache(vma, address, ptep); 3057 3058out_ptl: 3059 spin_unlock(ptl); 3060 3061 if (pagecache_page) { 3062 unlock_page(pagecache_page); 3063 put_page(pagecache_page); 3064 } 3065 if (page != pagecache_page) 3066 unlock_page(page); 3067 put_page(page); 3068 3069out_mutex: 3070 mutex_unlock(&htlb_fault_mutex_table[hash]); 3071 return ret; 3072} 3073 3074long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 3075 struct page **pages, struct vm_area_struct **vmas, 3076 unsigned long *position, unsigned long *nr_pages, 3077 long i, unsigned int flags) 3078{ 3079 unsigned long pfn_offset; 3080 unsigned long vaddr = *position; 3081 unsigned long remainder = *nr_pages; 3082 struct hstate *h = hstate_vma(vma); 3083 3084 while (vaddr < vma->vm_end && remainder) { 3085 pte_t *pte; 3086 spinlock_t *ptl = NULL; 3087 int absent; 3088 struct page *page; 3089 3090 /* 3091 * Some archs (sparc64, sh*) have multiple pte_ts to 3092 * each hugepage. We have to make sure we get the 3093 * first, for the page indexing below to work. 3094 * 3095 * Note that page table lock is not held when pte is null. 3096 */ 3097 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 3098 if (pte) 3099 ptl = huge_pte_lock(h, mm, pte); 3100 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 3101 3102 /* 3103 * When coredumping, it suits get_dump_page if we just return 3104 * an error where there's an empty slot with no huge pagecache 3105 * to back it. This way, we avoid allocating a hugepage, and 3106 * the sparse dumpfile avoids allocating disk blocks, but its 3107 * huge holes still show up with zeroes where they need to be. 3108 */ 3109 if (absent && (flags & FOLL_DUMP) && 3110 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 3111 if (pte) 3112 spin_unlock(ptl); 3113 remainder = 0; 3114 break; 3115 } 3116 3117 /* 3118 * We need call hugetlb_fault for both hugepages under migration 3119 * (in which case hugetlb_fault waits for the migration,) and 3120 * hwpoisoned hugepages (in which case we need to prevent the 3121 * caller from accessing to them.) In order to do this, we use 3122 * here is_swap_pte instead of is_hugetlb_entry_migration and 3123 * is_hugetlb_entry_hwpoisoned. This is because it simply covers 3124 * both cases, and because we can't follow correct pages 3125 * directly from any kind of swap entries. 3126 */ 3127 if (absent || is_swap_pte(huge_ptep_get(pte)) || 3128 ((flags & FOLL_WRITE) && 3129 !huge_pte_write(huge_ptep_get(pte)))) { 3130 int ret; 3131 3132 if (pte) 3133 spin_unlock(ptl); 3134 ret = hugetlb_fault(mm, vma, vaddr, 3135 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 3136 if (!(ret & VM_FAULT_ERROR)) 3137 continue; 3138 3139 remainder = 0; 3140 break; 3141 } 3142 3143 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 3144 page = pte_page(huge_ptep_get(pte)); 3145same_page: 3146 if (pages) { 3147 pages[i] = mem_map_offset(page, pfn_offset); 3148 get_page_foll(pages[i]); 3149 } 3150 3151 if (vmas) 3152 vmas[i] = vma; 3153 3154 vaddr += PAGE_SIZE; 3155 ++pfn_offset; 3156 --remainder; 3157 ++i; 3158 if (vaddr < vma->vm_end && remainder && 3159 pfn_offset < pages_per_huge_page(h)) { 3160 /* 3161 * We use pfn_offset to avoid touching the pageframes 3162 * of this compound page. 3163 */ 3164 goto same_page; 3165 } 3166 spin_unlock(ptl); 3167 } 3168 *nr_pages = remainder; 3169 *position = vaddr; 3170 3171 return i ? i : -EFAULT; 3172} 3173 3174unsigned long hugetlb_change_protection(struct vm_area_struct *vma, 3175 unsigned long address, unsigned long end, pgprot_t newprot) 3176{ 3177 struct mm_struct *mm = vma->vm_mm; 3178 unsigned long start = address; 3179 pte_t *ptep; 3180 pte_t pte; 3181 struct hstate *h = hstate_vma(vma); 3182 unsigned long pages = 0; 3183 3184 BUG_ON(address >= end); 3185 flush_cache_range(vma, address, end); 3186 3187 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 3188 for (; address < end; address += huge_page_size(h)) { 3189 spinlock_t *ptl; 3190 ptep = huge_pte_offset(mm, address); 3191 if (!ptep) 3192 continue; 3193 ptl = huge_pte_lock(h, mm, ptep); 3194 if (huge_pmd_unshare(mm, &address, ptep)) { 3195 pages++; 3196 spin_unlock(ptl); 3197 continue; 3198 } 3199 if (!huge_pte_none(huge_ptep_get(ptep))) { 3200 pte = huge_ptep_get_and_clear(mm, address, ptep); 3201 pte = pte_mkhuge(huge_pte_modify(pte, newprot)); 3202 pte = arch_make_huge_pte(pte, vma, NULL, 0); 3203 set_huge_pte_at(mm, address, ptep, pte); 3204 pages++; 3205 } 3206 spin_unlock(ptl); 3207 } 3208 /* 3209 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare 3210 * may have cleared our pud entry and done put_page on the page table: 3211 * once we release i_mmap_mutex, another task can do the final put_page 3212 * and that page table be reused and filled with junk. 3213 */ 3214 flush_tlb_range(vma, start, end); 3215 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 3216 3217 return pages << h->order; 3218} 3219 3220int hugetlb_reserve_pages(struct inode *inode, 3221 long from, long to, 3222 struct vm_area_struct *vma, 3223 vm_flags_t vm_flags) 3224{ 3225 long ret, chg; 3226 struct hstate *h = hstate_inode(inode); 3227 struct hugepage_subpool *spool = subpool_inode(inode); 3228 struct resv_map *resv_map; 3229 3230 /* 3231 * Only apply hugepage reservation if asked. At fault time, an 3232 * attempt will be made for VM_NORESERVE to allocate a page 3233 * without using reserves 3234 */ 3235 if (vm_flags & VM_NORESERVE) 3236 return 0; 3237 3238 /* 3239 * Shared mappings base their reservation on the number of pages that 3240 * are already allocated on behalf of the file. Private mappings need 3241 * to reserve the full area even if read-only as mprotect() may be 3242 * called to make the mapping read-write. Assume !vma is a shm mapping 3243 */ 3244 if (!vma || vma->vm_flags & VM_MAYSHARE) { 3245 resv_map = inode_resv_map(inode); 3246 3247 chg = region_chg(resv_map, from, to); 3248 3249 } else { 3250 resv_map = resv_map_alloc(); 3251 if (!resv_map) 3252 return -ENOMEM; 3253 3254 chg = to - from; 3255 3256 set_vma_resv_map(vma, resv_map); 3257 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 3258 } 3259 3260 if (chg < 0) { 3261 ret = chg; 3262 goto out_err; 3263 } 3264 3265 /* There must be enough pages in the subpool for the mapping */ 3266 if (hugepage_subpool_get_pages(spool, chg)) { 3267 ret = -ENOSPC; 3268 goto out_err; 3269 } 3270 3271 /* 3272 * Check enough hugepages are available for the reservation. 3273 * Hand the pages back to the subpool if there are not 3274 */ 3275 ret = hugetlb_acct_memory(h, chg); 3276 if (ret < 0) { 3277 hugepage_subpool_put_pages(spool, chg); 3278 goto out_err; 3279 } 3280 3281 /* 3282 * Account for the reservations made. Shared mappings record regions 3283 * that have reservations as they are shared by multiple VMAs. 3284 * When the last VMA disappears, the region map says how much 3285 * the reservation was and the page cache tells how much of 3286 * the reservation was consumed. Private mappings are per-VMA and 3287 * only the consumed reservations are tracked. When the VMA 3288 * disappears, the original reservation is the VMA size and the 3289 * consumed reservations are stored in the map. Hence, nothing 3290 * else has to be done for private mappings here 3291 */ 3292 if (!vma || vma->vm_flags & VM_MAYSHARE) 3293 region_add(resv_map, from, to); 3294 return 0; 3295out_err: 3296 if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 3297 kref_put(&resv_map->refs, resv_map_release); 3298 return ret; 3299} 3300 3301void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 3302{ 3303 struct hstate *h = hstate_inode(inode); 3304 struct resv_map *resv_map = inode_resv_map(inode); 3305 long chg = 0; 3306 struct hugepage_subpool *spool = subpool_inode(inode); 3307 3308 if (resv_map) 3309 chg = region_truncate(resv_map, offset); 3310 spin_lock(&inode->i_lock); 3311 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 3312 spin_unlock(&inode->i_lock); 3313 3314 hugepage_subpool_put_pages(spool, (chg - freed)); 3315 hugetlb_acct_memory(h, -(chg - freed)); 3316} 3317 3318#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE 3319static unsigned long page_table_shareable(struct vm_area_struct *svma, 3320 struct vm_area_struct *vma, 3321 unsigned long addr, pgoff_t idx) 3322{ 3323 unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + 3324 svma->vm_start; 3325 unsigned long sbase = saddr & PUD_MASK; 3326 unsigned long s_end = sbase + PUD_SIZE; 3327 3328 /* Allow segments to share if only one is marked locked */ 3329 unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED; 3330 unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED; 3331 3332 /* 3333 * match the virtual addresses, permission and the alignment of the 3334 * page table page. 3335 */ 3336 if (pmd_index(addr) != pmd_index(saddr) || 3337 vm_flags != svm_flags || 3338 sbase < svma->vm_start || svma->vm_end < s_end) 3339 return 0; 3340 3341 return saddr; 3342} 3343 3344static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) 3345{ 3346 unsigned long base = addr & PUD_MASK; 3347 unsigned long end = base + PUD_SIZE; 3348 3349 /* 3350 * check on proper vm_flags and page table alignment 3351 */ 3352 if (vma->vm_flags & VM_MAYSHARE && 3353 vma->vm_start <= base && end <= vma->vm_end) 3354 return 1; 3355 return 0; 3356} 3357 3358/* 3359 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() 3360 * and returns the corresponding pte. While this is not necessary for the 3361 * !shared pmd case because we can allocate the pmd later as well, it makes the 3362 * code much cleaner. pmd allocation is essential for the shared case because 3363 * pud has to be populated inside the same i_mmap_mutex section - otherwise 3364 * racing tasks could either miss the sharing (see huge_pte_offset) or select a 3365 * bad pmd for sharing. 3366 */ 3367pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) 3368{ 3369 struct vm_area_struct *vma = find_vma(mm, addr); 3370 struct address_space *mapping = vma->vm_file->f_mapping; 3371 pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + 3372 vma->vm_pgoff; 3373 struct vm_area_struct *svma; 3374 unsigned long saddr; 3375 pte_t *spte = NULL; 3376 pte_t *pte; 3377 spinlock_t *ptl; 3378 3379 if (!vma_shareable(vma, addr)) 3380 return (pte_t *)pmd_alloc(mm, pud, addr); 3381 3382 mutex_lock(&mapping->i_mmap_mutex); 3383 vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { 3384 if (svma == vma) 3385 continue; 3386 3387 saddr = page_table_shareable(svma, vma, addr, idx); 3388 if (saddr) { 3389 spte = huge_pte_offset(svma->vm_mm, saddr); 3390 if (spte) { 3391 get_page(virt_to_page(spte)); 3392 break; 3393 } 3394 } 3395 } 3396 3397 if (!spte) 3398 goto out; 3399 3400 ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); 3401 spin_lock(ptl); 3402 if (pud_none(*pud)) 3403 pud_populate(mm, pud, 3404 (pmd_t *)((unsigned long)spte & PAGE_MASK)); 3405 else 3406 put_page(virt_to_page(spte)); 3407 spin_unlock(ptl); 3408out: 3409 pte = (pte_t *)pmd_alloc(mm, pud, addr); 3410 mutex_unlock(&mapping->i_mmap_mutex); 3411 return pte; 3412} 3413 3414/* 3415 * unmap huge page backed by shared pte. 3416 * 3417 * Hugetlb pte page is ref counted at the time of mapping. If pte is shared 3418 * indicated by page_count > 1, unmap is achieved by clearing pud and 3419 * decrementing the ref count. If count == 1, the pte page is not shared. 3420 * 3421 * called with page table lock held. 3422 * 3423 * returns: 1 successfully unmapped a shared pte page 3424 * 0 the underlying pte page is not shared, or it is the last user 3425 */ 3426int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) 3427{ 3428 pgd_t *pgd = pgd_offset(mm, *addr); 3429 pud_t *pud = pud_offset(pgd, *addr); 3430 3431 BUG_ON(page_count(virt_to_page(ptep)) == 0); 3432 if (page_count(virt_to_page(ptep)) == 1) 3433 return 0; 3434 3435 pud_clear(pud); 3436 put_page(virt_to_page(ptep)); 3437 *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; 3438 return 1; 3439} 3440#define want_pmd_share() (1) 3441#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ 3442pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) 3443{ 3444 return NULL; 3445} 3446#define want_pmd_share() (0) 3447#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ 3448 3449#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB 3450pte_t *huge_pte_alloc(struct mm_struct *mm, 3451 unsigned long addr, unsigned long sz) 3452{ 3453 pgd_t *pgd; 3454 pud_t *pud; 3455 pte_t *pte = NULL; 3456 3457 pgd = pgd_offset(mm, addr); 3458 pud = pud_alloc(mm, pgd, addr); 3459 if (pud) { 3460 if (sz == PUD_SIZE) { 3461 pte = (pte_t *)pud; 3462 } else { 3463 BUG_ON(sz != PMD_SIZE); 3464 if (want_pmd_share() && pud_none(*pud)) 3465 pte = huge_pmd_share(mm, addr, pud); 3466 else 3467 pte = (pte_t *)pmd_alloc(mm, pud, addr); 3468 } 3469 } 3470 BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); 3471 3472 return pte; 3473} 3474 3475pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 3476{ 3477 pgd_t *pgd; 3478 pud_t *pud; 3479 pmd_t *pmd = NULL; 3480 3481 pgd = pgd_offset(mm, addr); 3482 if (pgd_present(*pgd)) { 3483 pud = pud_offset(pgd, addr); 3484 if (pud_present(*pud)) { 3485 if (pud_huge(*pud)) 3486 return (pte_t *)pud; 3487 pmd = pmd_offset(pud, addr); 3488 } 3489 } 3490 return (pte_t *) pmd; 3491} 3492 3493struct page * 3494follow_huge_pmd(struct mm_struct *mm, unsigned long address, 3495 pmd_t *pmd, int write) 3496{ 3497 struct page *page; 3498 3499 page = pte_page(*(pte_t *)pmd); 3500 if (page) 3501 page += ((address & ~PMD_MASK) >> PAGE_SHIFT); 3502 return page; 3503} 3504 3505struct page * 3506follow_huge_pud(struct mm_struct *mm, unsigned long address, 3507 pud_t *pud, int write) 3508{ 3509 struct page *page; 3510 3511 page = pte_page(*(pte_t *)pud); 3512 if (page) 3513 page += ((address & ~PUD_MASK) >> PAGE_SHIFT); 3514 return page; 3515} 3516 3517#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ 3518 3519/* Can be overriden by architectures */ 3520__attribute__((weak)) struct page * 3521follow_huge_pud(struct mm_struct *mm, unsigned long address, 3522 pud_t *pud, int write) 3523{ 3524 BUG(); 3525 return NULL; 3526} 3527 3528#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ 3529 3530#ifdef CONFIG_MEMORY_FAILURE 3531 3532/* Should be called in hugetlb_lock */ 3533static int is_hugepage_on_freelist(struct page *hpage) 3534{ 3535 struct page *page; 3536 struct page *tmp; 3537 struct hstate *h = page_hstate(hpage); 3538 int nid = page_to_nid(hpage); 3539 3540 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) 3541 if (page == hpage) 3542 return 1; 3543 return 0; 3544} 3545 3546/* 3547 * This function is called from memory failure code. 3548 * Assume the caller holds page lock of the head page. 3549 */ 3550int dequeue_hwpoisoned_huge_page(struct page *hpage) 3551{ 3552 struct hstate *h = page_hstate(hpage); 3553 int nid = page_to_nid(hpage); 3554 int ret = -EBUSY; 3555 3556 spin_lock(&hugetlb_lock); 3557 if (is_hugepage_on_freelist(hpage)) { 3558 /* 3559 * Hwpoisoned hugepage isn't linked to activelist or freelist, 3560 * but dangling hpage->lru can trigger list-debug warnings 3561 * (this happens when we call unpoison_memory() on it), 3562 * so let it point to itself with list_del_init(). 3563 */ 3564 list_del_init(&hpage->lru); 3565 set_page_refcounted(hpage); 3566 h->free_huge_pages--; 3567 h->free_huge_pages_node[nid]--; 3568 ret = 0; 3569 } 3570 spin_unlock(&hugetlb_lock); 3571 return ret; 3572} 3573#endif 3574 3575bool isolate_huge_page(struct page *page, struct list_head *list) 3576{ 3577 VM_BUG_ON_PAGE(!PageHead(page), page); 3578 if (!get_page_unless_zero(page)) 3579 return false; 3580 spin_lock(&hugetlb_lock); 3581 list_move_tail(&page->lru, list); 3582 spin_unlock(&hugetlb_lock); 3583 return true; 3584} 3585 3586void putback_active_hugepage(struct page *page) 3587{ 3588 VM_BUG_ON_PAGE(!PageHead(page), page); 3589 spin_lock(&hugetlb_lock); 3590 list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); 3591 spin_unlock(&hugetlb_lock); 3592 put_page(page); 3593} 3594 3595bool is_hugepage_active(struct page *page) 3596{ 3597 VM_BUG_ON_PAGE(!PageHuge(page), page); 3598 /* 3599 * This function can be called for a tail page because the caller, 3600 * scan_movable_pages, scans through a given pfn-range which typically 3601 * covers one memory block. In systems using gigantic hugepage (1GB 3602 * for x86_64,) a hugepage is larger than a memory block, and we don't 3603 * support migrating such large hugepages for now, so return false 3604 * when called for tail pages. 3605 */ 3606 if (PageTail(page)) 3607 return false; 3608 /* 3609 * Refcount of a hwpoisoned hugepages is 1, but they are not active, 3610 * so we should return false for them. 3611 */ 3612 if (unlikely(PageHWPoison(page))) 3613 return false; 3614 return page_count(page) > 0; 3615} 3616