hugetlb.c revision 6b2dbba8b6ac4df26f72eda1e5ea7bab9f950e08
1/* 2 * Generic hugetlb support. 3 * (C) William Irwin, April 2004 4 */ 5#include <linux/list.h> 6#include <linux/init.h> 7#include <linux/module.h> 8#include <linux/mm.h> 9#include <linux/seq_file.h> 10#include <linux/sysctl.h> 11#include <linux/highmem.h> 12#include <linux/mmu_notifier.h> 13#include <linux/nodemask.h> 14#include <linux/pagemap.h> 15#include <linux/mempolicy.h> 16#include <linux/cpuset.h> 17#include <linux/mutex.h> 18#include <linux/bootmem.h> 19#include <linux/sysfs.h> 20#include <linux/slab.h> 21#include <linux/rmap.h> 22#include <linux/swap.h> 23#include <linux/swapops.h> 24 25#include <asm/page.h> 26#include <asm/pgtable.h> 27#include <asm/tlb.h> 28 29#include <linux/io.h> 30#include <linux/hugetlb.h> 31#include <linux/hugetlb_cgroup.h> 32#include <linux/node.h> 33#include <linux/hugetlb_cgroup.h> 34#include "internal.h" 35 36const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; 37static gfp_t htlb_alloc_mask = GFP_HIGHUSER; 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, nr_huge_pages, and free_huge_pages 53 */ 54DEFINE_SPINLOCK(hugetlb_lock); 55 56static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) 57{ 58 bool free = (spool->count == 0) && (spool->used_hpages == 0); 59 60 spin_unlock(&spool->lock); 61 62 /* If no pages are used, and no other handles to the subpool 63 * remain, free the subpool the subpool remain */ 64 if (free) 65 kfree(spool); 66} 67 68struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) 69{ 70 struct hugepage_subpool *spool; 71 72 spool = kmalloc(sizeof(*spool), GFP_KERNEL); 73 if (!spool) 74 return NULL; 75 76 spin_lock_init(&spool->lock); 77 spool->count = 1; 78 spool->max_hpages = nr_blocks; 79 spool->used_hpages = 0; 80 81 return spool; 82} 83 84void hugepage_put_subpool(struct hugepage_subpool *spool) 85{ 86 spin_lock(&spool->lock); 87 BUG_ON(!spool->count); 88 spool->count--; 89 unlock_or_release_subpool(spool); 90} 91 92static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, 93 long delta) 94{ 95 int ret = 0; 96 97 if (!spool) 98 return 0; 99 100 spin_lock(&spool->lock); 101 if ((spool->used_hpages + delta) <= spool->max_hpages) { 102 spool->used_hpages += delta; 103 } else { 104 ret = -ENOMEM; 105 } 106 spin_unlock(&spool->lock); 107 108 return ret; 109} 110 111static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, 112 long delta) 113{ 114 if (!spool) 115 return; 116 117 spin_lock(&spool->lock); 118 spool->used_hpages -= delta; 119 /* If hugetlbfs_put_super couldn't free spool due to 120 * an outstanding quota reference, free it now. */ 121 unlock_or_release_subpool(spool); 122} 123 124static inline struct hugepage_subpool *subpool_inode(struct inode *inode) 125{ 126 return HUGETLBFS_SB(inode->i_sb)->spool; 127} 128 129static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) 130{ 131 return subpool_inode(vma->vm_file->f_dentry->d_inode); 132} 133 134/* 135 * Region tracking -- allows tracking of reservations and instantiated pages 136 * across the pages in a mapping. 137 * 138 * The region data structures are protected by a combination of the mmap_sem 139 * and the hugetlb_instantion_mutex. To access or modify a region the caller 140 * must either hold the mmap_sem for write, or the mmap_sem for read and 141 * the hugetlb_instantiation mutex: 142 * 143 * down_write(&mm->mmap_sem); 144 * or 145 * down_read(&mm->mmap_sem); 146 * mutex_lock(&hugetlb_instantiation_mutex); 147 */ 148struct file_region { 149 struct list_head link; 150 long from; 151 long to; 152}; 153 154static long region_add(struct list_head *head, long f, long t) 155{ 156 struct file_region *rg, *nrg, *trg; 157 158 /* Locate the region we are either in or before. */ 159 list_for_each_entry(rg, head, link) 160 if (f <= rg->to) 161 break; 162 163 /* Round our left edge to the current segment if it encloses us. */ 164 if (f > rg->from) 165 f = rg->from; 166 167 /* Check for and consume any regions we now overlap with. */ 168 nrg = rg; 169 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 170 if (&rg->link == head) 171 break; 172 if (rg->from > t) 173 break; 174 175 /* If this area reaches higher then extend our area to 176 * include it completely. If this is not the first area 177 * which we intend to reuse, free it. */ 178 if (rg->to > t) 179 t = rg->to; 180 if (rg != nrg) { 181 list_del(&rg->link); 182 kfree(rg); 183 } 184 } 185 nrg->from = f; 186 nrg->to = t; 187 return 0; 188} 189 190static long region_chg(struct list_head *head, long f, long t) 191{ 192 struct file_region *rg, *nrg; 193 long chg = 0; 194 195 /* Locate the region we are before or in. */ 196 list_for_each_entry(rg, head, link) 197 if (f <= rg->to) 198 break; 199 200 /* If we are below the current region then a new region is required. 201 * Subtle, allocate a new region at the position but make it zero 202 * size such that we can guarantee to record the reservation. */ 203 if (&rg->link == head || t < rg->from) { 204 nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); 205 if (!nrg) 206 return -ENOMEM; 207 nrg->from = f; 208 nrg->to = f; 209 INIT_LIST_HEAD(&nrg->link); 210 list_add(&nrg->link, rg->link.prev); 211 212 return t - f; 213 } 214 215 /* Round our left edge to the current segment if it encloses us. */ 216 if (f > rg->from) 217 f = rg->from; 218 chg = t - f; 219 220 /* Check for and consume any regions we now overlap with. */ 221 list_for_each_entry(rg, rg->link.prev, link) { 222 if (&rg->link == head) 223 break; 224 if (rg->from > t) 225 return chg; 226 227 /* We overlap with this area, if it extends further than 228 * us then we must extend ourselves. Account for its 229 * existing reservation. */ 230 if (rg->to > t) { 231 chg += rg->to - t; 232 t = rg->to; 233 } 234 chg -= rg->to - rg->from; 235 } 236 return chg; 237} 238 239static long region_truncate(struct list_head *head, long end) 240{ 241 struct file_region *rg, *trg; 242 long chg = 0; 243 244 /* Locate the region we are either in or before. */ 245 list_for_each_entry(rg, head, link) 246 if (end <= rg->to) 247 break; 248 if (&rg->link == head) 249 return 0; 250 251 /* If we are in the middle of a region then adjust it. */ 252 if (end > rg->from) { 253 chg = rg->to - end; 254 rg->to = end; 255 rg = list_entry(rg->link.next, typeof(*rg), link); 256 } 257 258 /* Drop any remaining regions. */ 259 list_for_each_entry_safe(rg, trg, rg->link.prev, link) { 260 if (&rg->link == head) 261 break; 262 chg += rg->to - rg->from; 263 list_del(&rg->link); 264 kfree(rg); 265 } 266 return chg; 267} 268 269static long region_count(struct list_head *head, long f, long t) 270{ 271 struct file_region *rg; 272 long chg = 0; 273 274 /* Locate each segment we overlap with, and count that overlap. */ 275 list_for_each_entry(rg, head, link) { 276 long seg_from; 277 long seg_to; 278 279 if (rg->to <= f) 280 continue; 281 if (rg->from >= t) 282 break; 283 284 seg_from = max(rg->from, f); 285 seg_to = min(rg->to, t); 286 287 chg += seg_to - seg_from; 288 } 289 290 return chg; 291} 292 293/* 294 * Convert the address within this vma to the page offset within 295 * the mapping, in pagecache page units; huge pages here. 296 */ 297static pgoff_t vma_hugecache_offset(struct hstate *h, 298 struct vm_area_struct *vma, unsigned long address) 299{ 300 return ((address - vma->vm_start) >> huge_page_shift(h)) + 301 (vma->vm_pgoff >> huge_page_order(h)); 302} 303 304pgoff_t linear_hugepage_index(struct vm_area_struct *vma, 305 unsigned long address) 306{ 307 return vma_hugecache_offset(hstate_vma(vma), vma, address); 308} 309 310/* 311 * Return the size of the pages allocated when backing a VMA. In the majority 312 * cases this will be same size as used by the page table entries. 313 */ 314unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) 315{ 316 struct hstate *hstate; 317 318 if (!is_vm_hugetlb_page(vma)) 319 return PAGE_SIZE; 320 321 hstate = hstate_vma(vma); 322 323 return 1UL << (hstate->order + PAGE_SHIFT); 324} 325EXPORT_SYMBOL_GPL(vma_kernel_pagesize); 326 327/* 328 * Return the page size being used by the MMU to back a VMA. In the majority 329 * of cases, the page size used by the kernel matches the MMU size. On 330 * architectures where it differs, an architecture-specific version of this 331 * function is required. 332 */ 333#ifndef vma_mmu_pagesize 334unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 335{ 336 return vma_kernel_pagesize(vma); 337} 338#endif 339 340/* 341 * Flags for MAP_PRIVATE reservations. These are stored in the bottom 342 * bits of the reservation map pointer, which are always clear due to 343 * alignment. 344 */ 345#define HPAGE_RESV_OWNER (1UL << 0) 346#define HPAGE_RESV_UNMAPPED (1UL << 1) 347#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) 348 349/* 350 * These helpers are used to track how many pages are reserved for 351 * faults in a MAP_PRIVATE mapping. Only the process that called mmap() 352 * is guaranteed to have their future faults succeed. 353 * 354 * With the exception of reset_vma_resv_huge_pages() which is called at fork(), 355 * the reserve counters are updated with the hugetlb_lock held. It is safe 356 * to reset the VMA at fork() time as it is not in use yet and there is no 357 * chance of the global counters getting corrupted as a result of the values. 358 * 359 * The private mapping reservation is represented in a subtly different 360 * manner to a shared mapping. A shared mapping has a region map associated 361 * with the underlying file, this region map represents the backing file 362 * pages which have ever had a reservation assigned which this persists even 363 * after the page is instantiated. A private mapping has a region map 364 * associated with the original mmap which is attached to all VMAs which 365 * reference it, this region map represents those offsets which have consumed 366 * reservation ie. where pages have been instantiated. 367 */ 368static unsigned long get_vma_private_data(struct vm_area_struct *vma) 369{ 370 return (unsigned long)vma->vm_private_data; 371} 372 373static void set_vma_private_data(struct vm_area_struct *vma, 374 unsigned long value) 375{ 376 vma->vm_private_data = (void *)value; 377} 378 379struct resv_map { 380 struct kref refs; 381 struct list_head regions; 382}; 383 384static struct resv_map *resv_map_alloc(void) 385{ 386 struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); 387 if (!resv_map) 388 return NULL; 389 390 kref_init(&resv_map->refs); 391 INIT_LIST_HEAD(&resv_map->regions); 392 393 return resv_map; 394} 395 396static void resv_map_release(struct kref *ref) 397{ 398 struct resv_map *resv_map = container_of(ref, struct resv_map, refs); 399 400 /* Clear out any active regions before we release the map. */ 401 region_truncate(&resv_map->regions, 0); 402 kfree(resv_map); 403} 404 405static struct resv_map *vma_resv_map(struct vm_area_struct *vma) 406{ 407 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 408 if (!(vma->vm_flags & VM_MAYSHARE)) 409 return (struct resv_map *)(get_vma_private_data(vma) & 410 ~HPAGE_RESV_MASK); 411 return NULL; 412} 413 414static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) 415{ 416 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 417 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 418 419 set_vma_private_data(vma, (get_vma_private_data(vma) & 420 HPAGE_RESV_MASK) | (unsigned long)map); 421} 422 423static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) 424{ 425 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 426 VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); 427 428 set_vma_private_data(vma, get_vma_private_data(vma) | flags); 429} 430 431static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) 432{ 433 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 434 435 return (get_vma_private_data(vma) & flag) != 0; 436} 437 438/* Decrement the reserved pages in the hugepage pool by one */ 439static void decrement_hugepage_resv_vma(struct hstate *h, 440 struct vm_area_struct *vma) 441{ 442 if (vma->vm_flags & VM_NORESERVE) 443 return; 444 445 if (vma->vm_flags & VM_MAYSHARE) { 446 /* Shared mappings always use reserves */ 447 h->resv_huge_pages--; 448 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 449 /* 450 * Only the process that called mmap() has reserves for 451 * private mappings. 452 */ 453 h->resv_huge_pages--; 454 } 455} 456 457/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ 458void reset_vma_resv_huge_pages(struct vm_area_struct *vma) 459{ 460 VM_BUG_ON(!is_vm_hugetlb_page(vma)); 461 if (!(vma->vm_flags & VM_MAYSHARE)) 462 vma->vm_private_data = (void *)0; 463} 464 465/* Returns true if the VMA has associated reserve pages */ 466static int vma_has_reserves(struct vm_area_struct *vma) 467{ 468 if (vma->vm_flags & VM_MAYSHARE) 469 return 1; 470 if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) 471 return 1; 472 return 0; 473} 474 475static void copy_gigantic_page(struct page *dst, struct page *src) 476{ 477 int i; 478 struct hstate *h = page_hstate(src); 479 struct page *dst_base = dst; 480 struct page *src_base = src; 481 482 for (i = 0; i < pages_per_huge_page(h); ) { 483 cond_resched(); 484 copy_highpage(dst, src); 485 486 i++; 487 dst = mem_map_next(dst, dst_base, i); 488 src = mem_map_next(src, src_base, i); 489 } 490} 491 492void copy_huge_page(struct page *dst, struct page *src) 493{ 494 int i; 495 struct hstate *h = page_hstate(src); 496 497 if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { 498 copy_gigantic_page(dst, src); 499 return; 500 } 501 502 might_sleep(); 503 for (i = 0; i < pages_per_huge_page(h); i++) { 504 cond_resched(); 505 copy_highpage(dst + i, src + i); 506 } 507} 508 509static void enqueue_huge_page(struct hstate *h, struct page *page) 510{ 511 int nid = page_to_nid(page); 512 list_move(&page->lru, &h->hugepage_freelists[nid]); 513 h->free_huge_pages++; 514 h->free_huge_pages_node[nid]++; 515} 516 517static struct page *dequeue_huge_page_node(struct hstate *h, int nid) 518{ 519 struct page *page; 520 521 if (list_empty(&h->hugepage_freelists[nid])) 522 return NULL; 523 page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); 524 list_move(&page->lru, &h->hugepage_activelist); 525 set_page_refcounted(page); 526 h->free_huge_pages--; 527 h->free_huge_pages_node[nid]--; 528 return page; 529} 530 531static struct page *dequeue_huge_page_vma(struct hstate *h, 532 struct vm_area_struct *vma, 533 unsigned long address, int avoid_reserve) 534{ 535 struct page *page = NULL; 536 struct mempolicy *mpol; 537 nodemask_t *nodemask; 538 struct zonelist *zonelist; 539 struct zone *zone; 540 struct zoneref *z; 541 unsigned int cpuset_mems_cookie; 542 543retry_cpuset: 544 cpuset_mems_cookie = get_mems_allowed(); 545 zonelist = huge_zonelist(vma, address, 546 htlb_alloc_mask, &mpol, &nodemask); 547 /* 548 * A child process with MAP_PRIVATE mappings created by their parent 549 * have no page reserves. This check ensures that reservations are 550 * not "stolen". The child may still get SIGKILLed 551 */ 552 if (!vma_has_reserves(vma) && 553 h->free_huge_pages - h->resv_huge_pages == 0) 554 goto err; 555 556 /* If reserves cannot be used, ensure enough pages are in the pool */ 557 if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) 558 goto err; 559 560 for_each_zone_zonelist_nodemask(zone, z, zonelist, 561 MAX_NR_ZONES - 1, nodemask) { 562 if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { 563 page = dequeue_huge_page_node(h, zone_to_nid(zone)); 564 if (page) { 565 if (!avoid_reserve) 566 decrement_hugepage_resv_vma(h, vma); 567 break; 568 } 569 } 570 } 571 572 mpol_cond_put(mpol); 573 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page)) 574 goto retry_cpuset; 575 return page; 576 577err: 578 mpol_cond_put(mpol); 579 return NULL; 580} 581 582static void update_and_free_page(struct hstate *h, struct page *page) 583{ 584 int i; 585 586 VM_BUG_ON(h->order >= MAX_ORDER); 587 588 h->nr_huge_pages--; 589 h->nr_huge_pages_node[page_to_nid(page)]--; 590 for (i = 0; i < pages_per_huge_page(h); i++) { 591 page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 592 1 << PG_referenced | 1 << PG_dirty | 593 1 << PG_active | 1 << PG_reserved | 594 1 << PG_private | 1 << PG_writeback); 595 } 596 VM_BUG_ON(hugetlb_cgroup_from_page(page)); 597 set_compound_page_dtor(page, NULL); 598 set_page_refcounted(page); 599 arch_release_hugepage(page); 600 __free_pages(page, huge_page_order(h)); 601} 602 603struct hstate *size_to_hstate(unsigned long size) 604{ 605 struct hstate *h; 606 607 for_each_hstate(h) { 608 if (huge_page_size(h) == size) 609 return h; 610 } 611 return NULL; 612} 613 614static void free_huge_page(struct page *page) 615{ 616 /* 617 * Can't pass hstate in here because it is called from the 618 * compound page destructor. 619 */ 620 struct hstate *h = page_hstate(page); 621 int nid = page_to_nid(page); 622 struct hugepage_subpool *spool = 623 (struct hugepage_subpool *)page_private(page); 624 625 set_page_private(page, 0); 626 page->mapping = NULL; 627 BUG_ON(page_count(page)); 628 BUG_ON(page_mapcount(page)); 629 630 spin_lock(&hugetlb_lock); 631 hugetlb_cgroup_uncharge_page(hstate_index(h), 632 pages_per_huge_page(h), page); 633 if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { 634 /* remove the page from active list */ 635 list_del(&page->lru); 636 update_and_free_page(h, page); 637 h->surplus_huge_pages--; 638 h->surplus_huge_pages_node[nid]--; 639 } else { 640 arch_clear_hugepage_flags(page); 641 enqueue_huge_page(h, page); 642 } 643 spin_unlock(&hugetlb_lock); 644 hugepage_subpool_put_pages(spool, 1); 645} 646 647static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) 648{ 649 INIT_LIST_HEAD(&page->lru); 650 set_compound_page_dtor(page, free_huge_page); 651 spin_lock(&hugetlb_lock); 652 set_hugetlb_cgroup(page, NULL); 653 h->nr_huge_pages++; 654 h->nr_huge_pages_node[nid]++; 655 spin_unlock(&hugetlb_lock); 656 put_page(page); /* free it into the hugepage allocator */ 657} 658 659static void prep_compound_gigantic_page(struct page *page, unsigned long order) 660{ 661 int i; 662 int nr_pages = 1 << order; 663 struct page *p = page + 1; 664 665 /* we rely on prep_new_huge_page to set the destructor */ 666 set_compound_order(page, order); 667 __SetPageHead(page); 668 for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { 669 __SetPageTail(p); 670 set_page_count(p, 0); 671 p->first_page = page; 672 } 673} 674 675int PageHuge(struct page *page) 676{ 677 compound_page_dtor *dtor; 678 679 if (!PageCompound(page)) 680 return 0; 681 682 page = compound_head(page); 683 dtor = get_compound_page_dtor(page); 684 685 return dtor == free_huge_page; 686} 687EXPORT_SYMBOL_GPL(PageHuge); 688 689static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) 690{ 691 struct page *page; 692 693 if (h->order >= MAX_ORDER) 694 return NULL; 695 696 page = alloc_pages_exact_node(nid, 697 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 698 __GFP_REPEAT|__GFP_NOWARN, 699 huge_page_order(h)); 700 if (page) { 701 if (arch_prepare_hugepage(page)) { 702 __free_pages(page, huge_page_order(h)); 703 return NULL; 704 } 705 prep_new_huge_page(h, page, nid); 706 } 707 708 return page; 709} 710 711/* 712 * common helper functions for hstate_next_node_to_{alloc|free}. 713 * We may have allocated or freed a huge page based on a different 714 * nodes_allowed previously, so h->next_node_to_{alloc|free} might 715 * be outside of *nodes_allowed. Ensure that we use an allowed 716 * node for alloc or free. 717 */ 718static int next_node_allowed(int nid, nodemask_t *nodes_allowed) 719{ 720 nid = next_node(nid, *nodes_allowed); 721 if (nid == MAX_NUMNODES) 722 nid = first_node(*nodes_allowed); 723 VM_BUG_ON(nid >= MAX_NUMNODES); 724 725 return nid; 726} 727 728static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) 729{ 730 if (!node_isset(nid, *nodes_allowed)) 731 nid = next_node_allowed(nid, nodes_allowed); 732 return nid; 733} 734 735/* 736 * returns the previously saved node ["this node"] from which to 737 * allocate a persistent huge page for the pool and advance the 738 * next node from which to allocate, handling wrap at end of node 739 * mask. 740 */ 741static int hstate_next_node_to_alloc(struct hstate *h, 742 nodemask_t *nodes_allowed) 743{ 744 int nid; 745 746 VM_BUG_ON(!nodes_allowed); 747 748 nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); 749 h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); 750 751 return nid; 752} 753 754static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) 755{ 756 struct page *page; 757 int start_nid; 758 int next_nid; 759 int ret = 0; 760 761 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 762 next_nid = start_nid; 763 764 do { 765 page = alloc_fresh_huge_page_node(h, next_nid); 766 if (page) { 767 ret = 1; 768 break; 769 } 770 next_nid = hstate_next_node_to_alloc(h, nodes_allowed); 771 } while (next_nid != start_nid); 772 773 if (ret) 774 count_vm_event(HTLB_BUDDY_PGALLOC); 775 else 776 count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 777 778 return ret; 779} 780 781/* 782 * helper for free_pool_huge_page() - return the previously saved 783 * node ["this node"] from which to free a huge page. Advance the 784 * next node id whether or not we find a free huge page to free so 785 * that the next attempt to free addresses the next node. 786 */ 787static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) 788{ 789 int nid; 790 791 VM_BUG_ON(!nodes_allowed); 792 793 nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); 794 h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); 795 796 return nid; 797} 798 799/* 800 * Free huge page from pool from next node to free. 801 * Attempt to keep persistent huge pages more or less 802 * balanced over allowed nodes. 803 * Called with hugetlb_lock locked. 804 */ 805static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, 806 bool acct_surplus) 807{ 808 int start_nid; 809 int next_nid; 810 int ret = 0; 811 812 start_nid = hstate_next_node_to_free(h, nodes_allowed); 813 next_nid = start_nid; 814 815 do { 816 /* 817 * If we're returning unused surplus pages, only examine 818 * nodes with surplus pages. 819 */ 820 if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && 821 !list_empty(&h->hugepage_freelists[next_nid])) { 822 struct page *page = 823 list_entry(h->hugepage_freelists[next_nid].next, 824 struct page, lru); 825 list_del(&page->lru); 826 h->free_huge_pages--; 827 h->free_huge_pages_node[next_nid]--; 828 if (acct_surplus) { 829 h->surplus_huge_pages--; 830 h->surplus_huge_pages_node[next_nid]--; 831 } 832 update_and_free_page(h, page); 833 ret = 1; 834 break; 835 } 836 next_nid = hstate_next_node_to_free(h, nodes_allowed); 837 } while (next_nid != start_nid); 838 839 return ret; 840} 841 842static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) 843{ 844 struct page *page; 845 unsigned int r_nid; 846 847 if (h->order >= MAX_ORDER) 848 return NULL; 849 850 /* 851 * Assume we will successfully allocate the surplus page to 852 * prevent racing processes from causing the surplus to exceed 853 * overcommit 854 * 855 * This however introduces a different race, where a process B 856 * tries to grow the static hugepage pool while alloc_pages() is 857 * called by process A. B will only examine the per-node 858 * counters in determining if surplus huge pages can be 859 * converted to normal huge pages in adjust_pool_surplus(). A 860 * won't be able to increment the per-node counter, until the 861 * lock is dropped by B, but B doesn't drop hugetlb_lock until 862 * no more huge pages can be converted from surplus to normal 863 * state (and doesn't try to convert again). Thus, we have a 864 * case where a surplus huge page exists, the pool is grown, and 865 * the surplus huge page still exists after, even though it 866 * should just have been converted to a normal huge page. This 867 * does not leak memory, though, as the hugepage will be freed 868 * once it is out of use. It also does not allow the counters to 869 * go out of whack in adjust_pool_surplus() as we don't modify 870 * the node values until we've gotten the hugepage and only the 871 * per-node value is checked there. 872 */ 873 spin_lock(&hugetlb_lock); 874 if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { 875 spin_unlock(&hugetlb_lock); 876 return NULL; 877 } else { 878 h->nr_huge_pages++; 879 h->surplus_huge_pages++; 880 } 881 spin_unlock(&hugetlb_lock); 882 883 if (nid == NUMA_NO_NODE) 884 page = alloc_pages(htlb_alloc_mask|__GFP_COMP| 885 __GFP_REPEAT|__GFP_NOWARN, 886 huge_page_order(h)); 887 else 888 page = alloc_pages_exact_node(nid, 889 htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| 890 __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); 891 892 if (page && arch_prepare_hugepage(page)) { 893 __free_pages(page, huge_page_order(h)); 894 page = NULL; 895 } 896 897 spin_lock(&hugetlb_lock); 898 if (page) { 899 INIT_LIST_HEAD(&page->lru); 900 r_nid = page_to_nid(page); 901 set_compound_page_dtor(page, free_huge_page); 902 set_hugetlb_cgroup(page, NULL); 903 /* 904 * We incremented the global counters already 905 */ 906 h->nr_huge_pages_node[r_nid]++; 907 h->surplus_huge_pages_node[r_nid]++; 908 __count_vm_event(HTLB_BUDDY_PGALLOC); 909 } else { 910 h->nr_huge_pages--; 911 h->surplus_huge_pages--; 912 __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); 913 } 914 spin_unlock(&hugetlb_lock); 915 916 return page; 917} 918 919/* 920 * This allocation function is useful in the context where vma is irrelevant. 921 * E.g. soft-offlining uses this function because it only cares physical 922 * address of error page. 923 */ 924struct page *alloc_huge_page_node(struct hstate *h, int nid) 925{ 926 struct page *page; 927 928 spin_lock(&hugetlb_lock); 929 page = dequeue_huge_page_node(h, nid); 930 spin_unlock(&hugetlb_lock); 931 932 if (!page) 933 page = alloc_buddy_huge_page(h, nid); 934 935 return page; 936} 937 938/* 939 * Increase the hugetlb pool such that it can accommodate a reservation 940 * of size 'delta'. 941 */ 942static int gather_surplus_pages(struct hstate *h, int delta) 943{ 944 struct list_head surplus_list; 945 struct page *page, *tmp; 946 int ret, i; 947 int needed, allocated; 948 bool alloc_ok = true; 949 950 needed = (h->resv_huge_pages + delta) - h->free_huge_pages; 951 if (needed <= 0) { 952 h->resv_huge_pages += delta; 953 return 0; 954 } 955 956 allocated = 0; 957 INIT_LIST_HEAD(&surplus_list); 958 959 ret = -ENOMEM; 960retry: 961 spin_unlock(&hugetlb_lock); 962 for (i = 0; i < needed; i++) { 963 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 964 if (!page) { 965 alloc_ok = false; 966 break; 967 } 968 list_add(&page->lru, &surplus_list); 969 } 970 allocated += i; 971 972 /* 973 * After retaking hugetlb_lock, we need to recalculate 'needed' 974 * because either resv_huge_pages or free_huge_pages may have changed. 975 */ 976 spin_lock(&hugetlb_lock); 977 needed = (h->resv_huge_pages + delta) - 978 (h->free_huge_pages + allocated); 979 if (needed > 0) { 980 if (alloc_ok) 981 goto retry; 982 /* 983 * We were not able to allocate enough pages to 984 * satisfy the entire reservation so we free what 985 * we've allocated so far. 986 */ 987 goto free; 988 } 989 /* 990 * The surplus_list now contains _at_least_ the number of extra pages 991 * needed to accommodate the reservation. Add the appropriate number 992 * of pages to the hugetlb pool and free the extras back to the buddy 993 * allocator. Commit the entire reservation here to prevent another 994 * process from stealing the pages as they are added to the pool but 995 * before they are reserved. 996 */ 997 needed += allocated; 998 h->resv_huge_pages += delta; 999 ret = 0; 1000 1001 /* Free the needed pages to the hugetlb pool */ 1002 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1003 if ((--needed) < 0) 1004 break; 1005 /* 1006 * This page is now managed by the hugetlb allocator and has 1007 * no users -- drop the buddy allocator's reference. 1008 */ 1009 put_page_testzero(page); 1010 VM_BUG_ON(page_count(page)); 1011 enqueue_huge_page(h, page); 1012 } 1013free: 1014 spin_unlock(&hugetlb_lock); 1015 1016 /* Free unnecessary surplus pages to the buddy allocator */ 1017 if (!list_empty(&surplus_list)) { 1018 list_for_each_entry_safe(page, tmp, &surplus_list, lru) { 1019 put_page(page); 1020 } 1021 } 1022 spin_lock(&hugetlb_lock); 1023 1024 return ret; 1025} 1026 1027/* 1028 * When releasing a hugetlb pool reservation, any surplus pages that were 1029 * allocated to satisfy the reservation must be explicitly freed if they were 1030 * never used. 1031 * Called with hugetlb_lock held. 1032 */ 1033static void return_unused_surplus_pages(struct hstate *h, 1034 unsigned long unused_resv_pages) 1035{ 1036 unsigned long nr_pages; 1037 1038 /* Uncommit the reservation */ 1039 h->resv_huge_pages -= unused_resv_pages; 1040 1041 /* Cannot return gigantic pages currently */ 1042 if (h->order >= MAX_ORDER) 1043 return; 1044 1045 nr_pages = min(unused_resv_pages, h->surplus_huge_pages); 1046 1047 /* 1048 * We want to release as many surplus pages as possible, spread 1049 * evenly across all nodes with memory. Iterate across these nodes 1050 * until we can no longer free unreserved surplus pages. This occurs 1051 * when the nodes with surplus pages have no free pages. 1052 * free_pool_huge_page() will balance the the freed pages across the 1053 * on-line nodes with memory and will handle the hstate accounting. 1054 */ 1055 while (nr_pages--) { 1056 if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1)) 1057 break; 1058 } 1059} 1060 1061/* 1062 * Determine if the huge page at addr within the vma has an associated 1063 * reservation. Where it does not we will need to logically increase 1064 * reservation and actually increase subpool usage before an allocation 1065 * can occur. Where any new reservation would be required the 1066 * reservation change is prepared, but not committed. Once the page 1067 * has been allocated from the subpool and instantiated the change should 1068 * be committed via vma_commit_reservation. No action is required on 1069 * failure. 1070 */ 1071static long vma_needs_reservation(struct hstate *h, 1072 struct vm_area_struct *vma, unsigned long addr) 1073{ 1074 struct address_space *mapping = vma->vm_file->f_mapping; 1075 struct inode *inode = mapping->host; 1076 1077 if (vma->vm_flags & VM_MAYSHARE) { 1078 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1079 return region_chg(&inode->i_mapping->private_list, 1080 idx, idx + 1); 1081 1082 } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1083 return 1; 1084 1085 } else { 1086 long err; 1087 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1088 struct resv_map *reservations = vma_resv_map(vma); 1089 1090 err = region_chg(&reservations->regions, idx, idx + 1); 1091 if (err < 0) 1092 return err; 1093 return 0; 1094 } 1095} 1096static void vma_commit_reservation(struct hstate *h, 1097 struct vm_area_struct *vma, unsigned long addr) 1098{ 1099 struct address_space *mapping = vma->vm_file->f_mapping; 1100 struct inode *inode = mapping->host; 1101 1102 if (vma->vm_flags & VM_MAYSHARE) { 1103 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1104 region_add(&inode->i_mapping->private_list, idx, idx + 1); 1105 1106 } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { 1107 pgoff_t idx = vma_hugecache_offset(h, vma, addr); 1108 struct resv_map *reservations = vma_resv_map(vma); 1109 1110 /* Mark this page used in the map. */ 1111 region_add(&reservations->regions, idx, idx + 1); 1112 } 1113} 1114 1115static struct page *alloc_huge_page(struct vm_area_struct *vma, 1116 unsigned long addr, int avoid_reserve) 1117{ 1118 struct hugepage_subpool *spool = subpool_vma(vma); 1119 struct hstate *h = hstate_vma(vma); 1120 struct page *page; 1121 long chg; 1122 int ret, idx; 1123 struct hugetlb_cgroup *h_cg; 1124 1125 idx = hstate_index(h); 1126 /* 1127 * Processes that did not create the mapping will have no 1128 * reserves and will not have accounted against subpool 1129 * limit. Check that the subpool limit can be made before 1130 * satisfying the allocation MAP_NORESERVE mappings may also 1131 * need pages and subpool limit allocated allocated if no reserve 1132 * mapping overlaps. 1133 */ 1134 chg = vma_needs_reservation(h, vma, addr); 1135 if (chg < 0) 1136 return ERR_PTR(-ENOMEM); 1137 if (chg) 1138 if (hugepage_subpool_get_pages(spool, chg)) 1139 return ERR_PTR(-ENOSPC); 1140 1141 ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); 1142 if (ret) { 1143 hugepage_subpool_put_pages(spool, chg); 1144 return ERR_PTR(-ENOSPC); 1145 } 1146 spin_lock(&hugetlb_lock); 1147 page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); 1148 if (page) { 1149 /* update page cgroup details */ 1150 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), 1151 h_cg, page); 1152 spin_unlock(&hugetlb_lock); 1153 } else { 1154 spin_unlock(&hugetlb_lock); 1155 page = alloc_buddy_huge_page(h, NUMA_NO_NODE); 1156 if (!page) { 1157 hugetlb_cgroup_uncharge_cgroup(idx, 1158 pages_per_huge_page(h), 1159 h_cg); 1160 hugepage_subpool_put_pages(spool, chg); 1161 return ERR_PTR(-ENOSPC); 1162 } 1163 spin_lock(&hugetlb_lock); 1164 hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), 1165 h_cg, page); 1166 list_move(&page->lru, &h->hugepage_activelist); 1167 spin_unlock(&hugetlb_lock); 1168 } 1169 1170 set_page_private(page, (unsigned long)spool); 1171 1172 vma_commit_reservation(h, vma, addr); 1173 return page; 1174} 1175 1176int __weak alloc_bootmem_huge_page(struct hstate *h) 1177{ 1178 struct huge_bootmem_page *m; 1179 int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]); 1180 1181 while (nr_nodes) { 1182 void *addr; 1183 1184 addr = __alloc_bootmem_node_nopanic( 1185 NODE_DATA(hstate_next_node_to_alloc(h, 1186 &node_states[N_HIGH_MEMORY])), 1187 huge_page_size(h), huge_page_size(h), 0); 1188 1189 if (addr) { 1190 /* 1191 * Use the beginning of the huge page to store the 1192 * huge_bootmem_page struct (until gather_bootmem 1193 * puts them into the mem_map). 1194 */ 1195 m = addr; 1196 goto found; 1197 } 1198 nr_nodes--; 1199 } 1200 return 0; 1201 1202found: 1203 BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); 1204 /* Put them into a private list first because mem_map is not up yet */ 1205 list_add(&m->list, &huge_boot_pages); 1206 m->hstate = h; 1207 return 1; 1208} 1209 1210static void prep_compound_huge_page(struct page *page, int order) 1211{ 1212 if (unlikely(order > (MAX_ORDER - 1))) 1213 prep_compound_gigantic_page(page, order); 1214 else 1215 prep_compound_page(page, order); 1216} 1217 1218/* Put bootmem huge pages into the standard lists after mem_map is up */ 1219static void __init gather_bootmem_prealloc(void) 1220{ 1221 struct huge_bootmem_page *m; 1222 1223 list_for_each_entry(m, &huge_boot_pages, list) { 1224 struct hstate *h = m->hstate; 1225 struct page *page; 1226 1227#ifdef CONFIG_HIGHMEM 1228 page = pfn_to_page(m->phys >> PAGE_SHIFT); 1229 free_bootmem_late((unsigned long)m, 1230 sizeof(struct huge_bootmem_page)); 1231#else 1232 page = virt_to_page(m); 1233#endif 1234 __ClearPageReserved(page); 1235 WARN_ON(page_count(page) != 1); 1236 prep_compound_huge_page(page, h->order); 1237 prep_new_huge_page(h, page, page_to_nid(page)); 1238 /* 1239 * If we had gigantic hugepages allocated at boot time, we need 1240 * to restore the 'stolen' pages to totalram_pages in order to 1241 * fix confusing memory reports from free(1) and another 1242 * side-effects, like CommitLimit going negative. 1243 */ 1244 if (h->order > (MAX_ORDER - 1)) 1245 totalram_pages += 1 << h->order; 1246 } 1247} 1248 1249static void __init hugetlb_hstate_alloc_pages(struct hstate *h) 1250{ 1251 unsigned long i; 1252 1253 for (i = 0; i < h->max_huge_pages; ++i) { 1254 if (h->order >= MAX_ORDER) { 1255 if (!alloc_bootmem_huge_page(h)) 1256 break; 1257 } else if (!alloc_fresh_huge_page(h, 1258 &node_states[N_HIGH_MEMORY])) 1259 break; 1260 } 1261 h->max_huge_pages = i; 1262} 1263 1264static void __init hugetlb_init_hstates(void) 1265{ 1266 struct hstate *h; 1267 1268 for_each_hstate(h) { 1269 /* oversize hugepages were init'ed in early boot */ 1270 if (h->order < MAX_ORDER) 1271 hugetlb_hstate_alloc_pages(h); 1272 } 1273} 1274 1275static char * __init memfmt(char *buf, unsigned long n) 1276{ 1277 if (n >= (1UL << 30)) 1278 sprintf(buf, "%lu GB", n >> 30); 1279 else if (n >= (1UL << 20)) 1280 sprintf(buf, "%lu MB", n >> 20); 1281 else 1282 sprintf(buf, "%lu KB", n >> 10); 1283 return buf; 1284} 1285 1286static void __init report_hugepages(void) 1287{ 1288 struct hstate *h; 1289 1290 for_each_hstate(h) { 1291 char buf[32]; 1292 printk(KERN_INFO "HugeTLB registered %s page size, " 1293 "pre-allocated %ld pages\n", 1294 memfmt(buf, huge_page_size(h)), 1295 h->free_huge_pages); 1296 } 1297} 1298 1299#ifdef CONFIG_HIGHMEM 1300static void try_to_free_low(struct hstate *h, unsigned long count, 1301 nodemask_t *nodes_allowed) 1302{ 1303 int i; 1304 1305 if (h->order >= MAX_ORDER) 1306 return; 1307 1308 for_each_node_mask(i, *nodes_allowed) { 1309 struct page *page, *next; 1310 struct list_head *freel = &h->hugepage_freelists[i]; 1311 list_for_each_entry_safe(page, next, freel, lru) { 1312 if (count >= h->nr_huge_pages) 1313 return; 1314 if (PageHighMem(page)) 1315 continue; 1316 list_del(&page->lru); 1317 update_and_free_page(h, page); 1318 h->free_huge_pages--; 1319 h->free_huge_pages_node[page_to_nid(page)]--; 1320 } 1321 } 1322} 1323#else 1324static inline void try_to_free_low(struct hstate *h, unsigned long count, 1325 nodemask_t *nodes_allowed) 1326{ 1327} 1328#endif 1329 1330/* 1331 * Increment or decrement surplus_huge_pages. Keep node-specific counters 1332 * balanced by operating on them in a round-robin fashion. 1333 * Returns 1 if an adjustment was made. 1334 */ 1335static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, 1336 int delta) 1337{ 1338 int start_nid, next_nid; 1339 int ret = 0; 1340 1341 VM_BUG_ON(delta != -1 && delta != 1); 1342 1343 if (delta < 0) 1344 start_nid = hstate_next_node_to_alloc(h, nodes_allowed); 1345 else 1346 start_nid = hstate_next_node_to_free(h, nodes_allowed); 1347 next_nid = start_nid; 1348 1349 do { 1350 int nid = next_nid; 1351 if (delta < 0) { 1352 /* 1353 * To shrink on this node, there must be a surplus page 1354 */ 1355 if (!h->surplus_huge_pages_node[nid]) { 1356 next_nid = hstate_next_node_to_alloc(h, 1357 nodes_allowed); 1358 continue; 1359 } 1360 } 1361 if (delta > 0) { 1362 /* 1363 * Surplus cannot exceed the total number of pages 1364 */ 1365 if (h->surplus_huge_pages_node[nid] >= 1366 h->nr_huge_pages_node[nid]) { 1367 next_nid = hstate_next_node_to_free(h, 1368 nodes_allowed); 1369 continue; 1370 } 1371 } 1372 1373 h->surplus_huge_pages += delta; 1374 h->surplus_huge_pages_node[nid] += delta; 1375 ret = 1; 1376 break; 1377 } while (next_nid != start_nid); 1378 1379 return ret; 1380} 1381 1382#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) 1383static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, 1384 nodemask_t *nodes_allowed) 1385{ 1386 unsigned long min_count, ret; 1387 1388 if (h->order >= MAX_ORDER) 1389 return h->max_huge_pages; 1390 1391 /* 1392 * Increase the pool size 1393 * First take pages out of surplus state. Then make up the 1394 * remaining difference by allocating fresh huge pages. 1395 * 1396 * We might race with alloc_buddy_huge_page() here and be unable 1397 * to convert a surplus huge page to a normal huge page. That is 1398 * not critical, though, it just means the overall size of the 1399 * pool might be one hugepage larger than it needs to be, but 1400 * within all the constraints specified by the sysctls. 1401 */ 1402 spin_lock(&hugetlb_lock); 1403 while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { 1404 if (!adjust_pool_surplus(h, nodes_allowed, -1)) 1405 break; 1406 } 1407 1408 while (count > persistent_huge_pages(h)) { 1409 /* 1410 * If this allocation races such that we no longer need the 1411 * page, free_huge_page will handle it by freeing the page 1412 * and reducing the surplus. 1413 */ 1414 spin_unlock(&hugetlb_lock); 1415 ret = alloc_fresh_huge_page(h, nodes_allowed); 1416 spin_lock(&hugetlb_lock); 1417 if (!ret) 1418 goto out; 1419 1420 /* Bail for signals. Probably ctrl-c from user */ 1421 if (signal_pending(current)) 1422 goto out; 1423 } 1424 1425 /* 1426 * Decrease the pool size 1427 * First return free pages to the buddy allocator (being careful 1428 * to keep enough around to satisfy reservations). Then place 1429 * pages into surplus state as needed so the pool will shrink 1430 * to the desired size as pages become free. 1431 * 1432 * By placing pages into the surplus state independent of the 1433 * overcommit value, we are allowing the surplus pool size to 1434 * exceed overcommit. There are few sane options here. Since 1435 * alloc_buddy_huge_page() is checking the global counter, 1436 * though, we'll note that we're not allowed to exceed surplus 1437 * and won't grow the pool anywhere else. Not until one of the 1438 * sysctls are changed, or the surplus pages go out of use. 1439 */ 1440 min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; 1441 min_count = max(count, min_count); 1442 try_to_free_low(h, min_count, nodes_allowed); 1443 while (min_count < persistent_huge_pages(h)) { 1444 if (!free_pool_huge_page(h, nodes_allowed, 0)) 1445 break; 1446 } 1447 while (count < persistent_huge_pages(h)) { 1448 if (!adjust_pool_surplus(h, nodes_allowed, 1)) 1449 break; 1450 } 1451out: 1452 ret = persistent_huge_pages(h); 1453 spin_unlock(&hugetlb_lock); 1454 return ret; 1455} 1456 1457#define HSTATE_ATTR_RO(_name) \ 1458 static struct kobj_attribute _name##_attr = __ATTR_RO(_name) 1459 1460#define HSTATE_ATTR(_name) \ 1461 static struct kobj_attribute _name##_attr = \ 1462 __ATTR(_name, 0644, _name##_show, _name##_store) 1463 1464static struct kobject *hugepages_kobj; 1465static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1466 1467static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); 1468 1469static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) 1470{ 1471 int i; 1472 1473 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1474 if (hstate_kobjs[i] == kobj) { 1475 if (nidp) 1476 *nidp = NUMA_NO_NODE; 1477 return &hstates[i]; 1478 } 1479 1480 return kobj_to_node_hstate(kobj, nidp); 1481} 1482 1483static ssize_t nr_hugepages_show_common(struct kobject *kobj, 1484 struct kobj_attribute *attr, char *buf) 1485{ 1486 struct hstate *h; 1487 unsigned long nr_huge_pages; 1488 int nid; 1489 1490 h = kobj_to_hstate(kobj, &nid); 1491 if (nid == NUMA_NO_NODE) 1492 nr_huge_pages = h->nr_huge_pages; 1493 else 1494 nr_huge_pages = h->nr_huge_pages_node[nid]; 1495 1496 return sprintf(buf, "%lu\n", nr_huge_pages); 1497} 1498 1499static ssize_t nr_hugepages_store_common(bool obey_mempolicy, 1500 struct kobject *kobj, struct kobj_attribute *attr, 1501 const char *buf, size_t len) 1502{ 1503 int err; 1504 int nid; 1505 unsigned long count; 1506 struct hstate *h; 1507 NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); 1508 1509 err = strict_strtoul(buf, 10, &count); 1510 if (err) 1511 goto out; 1512 1513 h = kobj_to_hstate(kobj, &nid); 1514 if (h->order >= MAX_ORDER) { 1515 err = -EINVAL; 1516 goto out; 1517 } 1518 1519 if (nid == NUMA_NO_NODE) { 1520 /* 1521 * global hstate attribute 1522 */ 1523 if (!(obey_mempolicy && 1524 init_nodemask_of_mempolicy(nodes_allowed))) { 1525 NODEMASK_FREE(nodes_allowed); 1526 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1527 } 1528 } else if (nodes_allowed) { 1529 /* 1530 * per node hstate attribute: adjust count to global, 1531 * but restrict alloc/free to the specified node. 1532 */ 1533 count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; 1534 init_nodemask_of_node(nodes_allowed, nid); 1535 } else 1536 nodes_allowed = &node_states[N_HIGH_MEMORY]; 1537 1538 h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); 1539 1540 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 1541 NODEMASK_FREE(nodes_allowed); 1542 1543 return len; 1544out: 1545 NODEMASK_FREE(nodes_allowed); 1546 return err; 1547} 1548 1549static ssize_t nr_hugepages_show(struct kobject *kobj, 1550 struct kobj_attribute *attr, char *buf) 1551{ 1552 return nr_hugepages_show_common(kobj, attr, buf); 1553} 1554 1555static ssize_t nr_hugepages_store(struct kobject *kobj, 1556 struct kobj_attribute *attr, const char *buf, size_t len) 1557{ 1558 return nr_hugepages_store_common(false, kobj, attr, buf, len); 1559} 1560HSTATE_ATTR(nr_hugepages); 1561 1562#ifdef CONFIG_NUMA 1563 1564/* 1565 * hstate attribute for optionally mempolicy-based constraint on persistent 1566 * huge page alloc/free. 1567 */ 1568static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, 1569 struct kobj_attribute *attr, char *buf) 1570{ 1571 return nr_hugepages_show_common(kobj, attr, buf); 1572} 1573 1574static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, 1575 struct kobj_attribute *attr, const char *buf, size_t len) 1576{ 1577 return nr_hugepages_store_common(true, kobj, attr, buf, len); 1578} 1579HSTATE_ATTR(nr_hugepages_mempolicy); 1580#endif 1581 1582 1583static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, 1584 struct kobj_attribute *attr, char *buf) 1585{ 1586 struct hstate *h = kobj_to_hstate(kobj, NULL); 1587 return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); 1588} 1589 1590static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, 1591 struct kobj_attribute *attr, const char *buf, size_t count) 1592{ 1593 int err; 1594 unsigned long input; 1595 struct hstate *h = kobj_to_hstate(kobj, NULL); 1596 1597 if (h->order >= MAX_ORDER) 1598 return -EINVAL; 1599 1600 err = strict_strtoul(buf, 10, &input); 1601 if (err) 1602 return err; 1603 1604 spin_lock(&hugetlb_lock); 1605 h->nr_overcommit_huge_pages = input; 1606 spin_unlock(&hugetlb_lock); 1607 1608 return count; 1609} 1610HSTATE_ATTR(nr_overcommit_hugepages); 1611 1612static ssize_t free_hugepages_show(struct kobject *kobj, 1613 struct kobj_attribute *attr, char *buf) 1614{ 1615 struct hstate *h; 1616 unsigned long free_huge_pages; 1617 int nid; 1618 1619 h = kobj_to_hstate(kobj, &nid); 1620 if (nid == NUMA_NO_NODE) 1621 free_huge_pages = h->free_huge_pages; 1622 else 1623 free_huge_pages = h->free_huge_pages_node[nid]; 1624 1625 return sprintf(buf, "%lu\n", free_huge_pages); 1626} 1627HSTATE_ATTR_RO(free_hugepages); 1628 1629static ssize_t resv_hugepages_show(struct kobject *kobj, 1630 struct kobj_attribute *attr, char *buf) 1631{ 1632 struct hstate *h = kobj_to_hstate(kobj, NULL); 1633 return sprintf(buf, "%lu\n", h->resv_huge_pages); 1634} 1635HSTATE_ATTR_RO(resv_hugepages); 1636 1637static ssize_t surplus_hugepages_show(struct kobject *kobj, 1638 struct kobj_attribute *attr, char *buf) 1639{ 1640 struct hstate *h; 1641 unsigned long surplus_huge_pages; 1642 int nid; 1643 1644 h = kobj_to_hstate(kobj, &nid); 1645 if (nid == NUMA_NO_NODE) 1646 surplus_huge_pages = h->surplus_huge_pages; 1647 else 1648 surplus_huge_pages = h->surplus_huge_pages_node[nid]; 1649 1650 return sprintf(buf, "%lu\n", surplus_huge_pages); 1651} 1652HSTATE_ATTR_RO(surplus_hugepages); 1653 1654static struct attribute *hstate_attrs[] = { 1655 &nr_hugepages_attr.attr, 1656 &nr_overcommit_hugepages_attr.attr, 1657 &free_hugepages_attr.attr, 1658 &resv_hugepages_attr.attr, 1659 &surplus_hugepages_attr.attr, 1660#ifdef CONFIG_NUMA 1661 &nr_hugepages_mempolicy_attr.attr, 1662#endif 1663 NULL, 1664}; 1665 1666static struct attribute_group hstate_attr_group = { 1667 .attrs = hstate_attrs, 1668}; 1669 1670static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, 1671 struct kobject **hstate_kobjs, 1672 struct attribute_group *hstate_attr_group) 1673{ 1674 int retval; 1675 int hi = hstate_index(h); 1676 1677 hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); 1678 if (!hstate_kobjs[hi]) 1679 return -ENOMEM; 1680 1681 retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); 1682 if (retval) 1683 kobject_put(hstate_kobjs[hi]); 1684 1685 return retval; 1686} 1687 1688static void __init hugetlb_sysfs_init(void) 1689{ 1690 struct hstate *h; 1691 int err; 1692 1693 hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); 1694 if (!hugepages_kobj) 1695 return; 1696 1697 for_each_hstate(h) { 1698 err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, 1699 hstate_kobjs, &hstate_attr_group); 1700 if (err) 1701 printk(KERN_ERR "Hugetlb: Unable to add hstate %s", 1702 h->name); 1703 } 1704} 1705 1706#ifdef CONFIG_NUMA 1707 1708/* 1709 * node_hstate/s - associate per node hstate attributes, via their kobjects, 1710 * with node devices in node_devices[] using a parallel array. The array 1711 * index of a node device or _hstate == node id. 1712 * This is here to avoid any static dependency of the node device driver, in 1713 * the base kernel, on the hugetlb module. 1714 */ 1715struct node_hstate { 1716 struct kobject *hugepages_kobj; 1717 struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; 1718}; 1719struct node_hstate node_hstates[MAX_NUMNODES]; 1720 1721/* 1722 * A subset of global hstate attributes for node devices 1723 */ 1724static struct attribute *per_node_hstate_attrs[] = { 1725 &nr_hugepages_attr.attr, 1726 &free_hugepages_attr.attr, 1727 &surplus_hugepages_attr.attr, 1728 NULL, 1729}; 1730 1731static struct attribute_group per_node_hstate_attr_group = { 1732 .attrs = per_node_hstate_attrs, 1733}; 1734 1735/* 1736 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. 1737 * Returns node id via non-NULL nidp. 1738 */ 1739static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1740{ 1741 int nid; 1742 1743 for (nid = 0; nid < nr_node_ids; nid++) { 1744 struct node_hstate *nhs = &node_hstates[nid]; 1745 int i; 1746 for (i = 0; i < HUGE_MAX_HSTATE; i++) 1747 if (nhs->hstate_kobjs[i] == kobj) { 1748 if (nidp) 1749 *nidp = nid; 1750 return &hstates[i]; 1751 } 1752 } 1753 1754 BUG(); 1755 return NULL; 1756} 1757 1758/* 1759 * Unregister hstate attributes from a single node device. 1760 * No-op if no hstate attributes attached. 1761 */ 1762void hugetlb_unregister_node(struct node *node) 1763{ 1764 struct hstate *h; 1765 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1766 1767 if (!nhs->hugepages_kobj) 1768 return; /* no hstate attributes */ 1769 1770 for_each_hstate(h) { 1771 int idx = hstate_index(h); 1772 if (nhs->hstate_kobjs[idx]) { 1773 kobject_put(nhs->hstate_kobjs[idx]); 1774 nhs->hstate_kobjs[idx] = NULL; 1775 } 1776 } 1777 1778 kobject_put(nhs->hugepages_kobj); 1779 nhs->hugepages_kobj = NULL; 1780} 1781 1782/* 1783 * hugetlb module exit: unregister hstate attributes from node devices 1784 * that have them. 1785 */ 1786static void hugetlb_unregister_all_nodes(void) 1787{ 1788 int nid; 1789 1790 /* 1791 * disable node device registrations. 1792 */ 1793 register_hugetlbfs_with_node(NULL, NULL); 1794 1795 /* 1796 * remove hstate attributes from any nodes that have them. 1797 */ 1798 for (nid = 0; nid < nr_node_ids; nid++) 1799 hugetlb_unregister_node(&node_devices[nid]); 1800} 1801 1802/* 1803 * Register hstate attributes for a single node device. 1804 * No-op if attributes already registered. 1805 */ 1806void hugetlb_register_node(struct node *node) 1807{ 1808 struct hstate *h; 1809 struct node_hstate *nhs = &node_hstates[node->dev.id]; 1810 int err; 1811 1812 if (nhs->hugepages_kobj) 1813 return; /* already allocated */ 1814 1815 nhs->hugepages_kobj = kobject_create_and_add("hugepages", 1816 &node->dev.kobj); 1817 if (!nhs->hugepages_kobj) 1818 return; 1819 1820 for_each_hstate(h) { 1821 err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, 1822 nhs->hstate_kobjs, 1823 &per_node_hstate_attr_group); 1824 if (err) { 1825 printk(KERN_ERR "Hugetlb: Unable to add hstate %s" 1826 " for node %d\n", 1827 h->name, node->dev.id); 1828 hugetlb_unregister_node(node); 1829 break; 1830 } 1831 } 1832} 1833 1834/* 1835 * hugetlb init time: register hstate attributes for all registered node 1836 * devices of nodes that have memory. All on-line nodes should have 1837 * registered their associated device by this time. 1838 */ 1839static void hugetlb_register_all_nodes(void) 1840{ 1841 int nid; 1842 1843 for_each_node_state(nid, N_HIGH_MEMORY) { 1844 struct node *node = &node_devices[nid]; 1845 if (node->dev.id == nid) 1846 hugetlb_register_node(node); 1847 } 1848 1849 /* 1850 * Let the node device driver know we're here so it can 1851 * [un]register hstate attributes on node hotplug. 1852 */ 1853 register_hugetlbfs_with_node(hugetlb_register_node, 1854 hugetlb_unregister_node); 1855} 1856#else /* !CONFIG_NUMA */ 1857 1858static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) 1859{ 1860 BUG(); 1861 if (nidp) 1862 *nidp = -1; 1863 return NULL; 1864} 1865 1866static void hugetlb_unregister_all_nodes(void) { } 1867 1868static void hugetlb_register_all_nodes(void) { } 1869 1870#endif 1871 1872static void __exit hugetlb_exit(void) 1873{ 1874 struct hstate *h; 1875 1876 hugetlb_unregister_all_nodes(); 1877 1878 for_each_hstate(h) { 1879 kobject_put(hstate_kobjs[hstate_index(h)]); 1880 } 1881 1882 kobject_put(hugepages_kobj); 1883} 1884module_exit(hugetlb_exit); 1885 1886static int __init hugetlb_init(void) 1887{ 1888 /* Some platform decide whether they support huge pages at boot 1889 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when 1890 * there is no such support 1891 */ 1892 if (HPAGE_SHIFT == 0) 1893 return 0; 1894 1895 if (!size_to_hstate(default_hstate_size)) { 1896 default_hstate_size = HPAGE_SIZE; 1897 if (!size_to_hstate(default_hstate_size)) 1898 hugetlb_add_hstate(HUGETLB_PAGE_ORDER); 1899 } 1900 default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); 1901 if (default_hstate_max_huge_pages) 1902 default_hstate.max_huge_pages = default_hstate_max_huge_pages; 1903 1904 hugetlb_init_hstates(); 1905 1906 gather_bootmem_prealloc(); 1907 1908 report_hugepages(); 1909 1910 hugetlb_sysfs_init(); 1911 1912 hugetlb_register_all_nodes(); 1913 1914 return 0; 1915} 1916module_init(hugetlb_init); 1917 1918/* Should be called on processing a hugepagesz=... option */ 1919void __init hugetlb_add_hstate(unsigned order) 1920{ 1921 struct hstate *h; 1922 unsigned long i; 1923 1924 if (size_to_hstate(PAGE_SIZE << order)) { 1925 printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); 1926 return; 1927 } 1928 BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); 1929 BUG_ON(order == 0); 1930 h = &hstates[hugetlb_max_hstate++]; 1931 h->order = order; 1932 h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); 1933 h->nr_huge_pages = 0; 1934 h->free_huge_pages = 0; 1935 for (i = 0; i < MAX_NUMNODES; ++i) 1936 INIT_LIST_HEAD(&h->hugepage_freelists[i]); 1937 INIT_LIST_HEAD(&h->hugepage_activelist); 1938 h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]); 1939 h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]); 1940 snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", 1941 huge_page_size(h)/1024); 1942 /* 1943 * Add cgroup control files only if the huge page consists 1944 * of more than two normal pages. This is because we use 1945 * page[2].lru.next for storing cgoup details. 1946 */ 1947 if (order >= HUGETLB_CGROUP_MIN_ORDER) 1948 hugetlb_cgroup_file_init(hugetlb_max_hstate - 1); 1949 1950 parsed_hstate = h; 1951} 1952 1953static int __init hugetlb_nrpages_setup(char *s) 1954{ 1955 unsigned long *mhp; 1956 static unsigned long *last_mhp; 1957 1958 /* 1959 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, 1960 * so this hugepages= parameter goes to the "default hstate". 1961 */ 1962 if (!hugetlb_max_hstate) 1963 mhp = &default_hstate_max_huge_pages; 1964 else 1965 mhp = &parsed_hstate->max_huge_pages; 1966 1967 if (mhp == last_mhp) { 1968 printk(KERN_WARNING "hugepages= specified twice without " 1969 "interleaving hugepagesz=, ignoring\n"); 1970 return 1; 1971 } 1972 1973 if (sscanf(s, "%lu", mhp) <= 0) 1974 *mhp = 0; 1975 1976 /* 1977 * Global state is always initialized later in hugetlb_init. 1978 * But we need to allocate >= MAX_ORDER hstates here early to still 1979 * use the bootmem allocator. 1980 */ 1981 if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) 1982 hugetlb_hstate_alloc_pages(parsed_hstate); 1983 1984 last_mhp = mhp; 1985 1986 return 1; 1987} 1988__setup("hugepages=", hugetlb_nrpages_setup); 1989 1990static int __init hugetlb_default_setup(char *s) 1991{ 1992 default_hstate_size = memparse(s, &s); 1993 return 1; 1994} 1995__setup("default_hugepagesz=", hugetlb_default_setup); 1996 1997static unsigned int cpuset_mems_nr(unsigned int *array) 1998{ 1999 int node; 2000 unsigned int nr = 0; 2001 2002 for_each_node_mask(node, cpuset_current_mems_allowed) 2003 nr += array[node]; 2004 2005 return nr; 2006} 2007 2008#ifdef CONFIG_SYSCTL 2009static int hugetlb_sysctl_handler_common(bool obey_mempolicy, 2010 struct ctl_table *table, int write, 2011 void __user *buffer, size_t *length, loff_t *ppos) 2012{ 2013 struct hstate *h = &default_hstate; 2014 unsigned long tmp; 2015 int ret; 2016 2017 tmp = h->max_huge_pages; 2018 2019 if (write && h->order >= MAX_ORDER) 2020 return -EINVAL; 2021 2022 table->data = &tmp; 2023 table->maxlen = sizeof(unsigned long); 2024 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2025 if (ret) 2026 goto out; 2027 2028 if (write) { 2029 NODEMASK_ALLOC(nodemask_t, nodes_allowed, 2030 GFP_KERNEL | __GFP_NORETRY); 2031 if (!(obey_mempolicy && 2032 init_nodemask_of_mempolicy(nodes_allowed))) { 2033 NODEMASK_FREE(nodes_allowed); 2034 nodes_allowed = &node_states[N_HIGH_MEMORY]; 2035 } 2036 h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); 2037 2038 if (nodes_allowed != &node_states[N_HIGH_MEMORY]) 2039 NODEMASK_FREE(nodes_allowed); 2040 } 2041out: 2042 return ret; 2043} 2044 2045int hugetlb_sysctl_handler(struct ctl_table *table, int write, 2046 void __user *buffer, size_t *length, loff_t *ppos) 2047{ 2048 2049 return hugetlb_sysctl_handler_common(false, table, write, 2050 buffer, length, ppos); 2051} 2052 2053#ifdef CONFIG_NUMA 2054int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, 2055 void __user *buffer, size_t *length, loff_t *ppos) 2056{ 2057 return hugetlb_sysctl_handler_common(true, table, write, 2058 buffer, length, ppos); 2059} 2060#endif /* CONFIG_NUMA */ 2061 2062int hugetlb_treat_movable_handler(struct ctl_table *table, int write, 2063 void __user *buffer, 2064 size_t *length, loff_t *ppos) 2065{ 2066 proc_dointvec(table, write, buffer, length, ppos); 2067 if (hugepages_treat_as_movable) 2068 htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; 2069 else 2070 htlb_alloc_mask = GFP_HIGHUSER; 2071 return 0; 2072} 2073 2074int hugetlb_overcommit_handler(struct ctl_table *table, int write, 2075 void __user *buffer, 2076 size_t *length, loff_t *ppos) 2077{ 2078 struct hstate *h = &default_hstate; 2079 unsigned long tmp; 2080 int ret; 2081 2082 tmp = h->nr_overcommit_huge_pages; 2083 2084 if (write && h->order >= MAX_ORDER) 2085 return -EINVAL; 2086 2087 table->data = &tmp; 2088 table->maxlen = sizeof(unsigned long); 2089 ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); 2090 if (ret) 2091 goto out; 2092 2093 if (write) { 2094 spin_lock(&hugetlb_lock); 2095 h->nr_overcommit_huge_pages = tmp; 2096 spin_unlock(&hugetlb_lock); 2097 } 2098out: 2099 return ret; 2100} 2101 2102#endif /* CONFIG_SYSCTL */ 2103 2104void hugetlb_report_meminfo(struct seq_file *m) 2105{ 2106 struct hstate *h = &default_hstate; 2107 seq_printf(m, 2108 "HugePages_Total: %5lu\n" 2109 "HugePages_Free: %5lu\n" 2110 "HugePages_Rsvd: %5lu\n" 2111 "HugePages_Surp: %5lu\n" 2112 "Hugepagesize: %8lu kB\n", 2113 h->nr_huge_pages, 2114 h->free_huge_pages, 2115 h->resv_huge_pages, 2116 h->surplus_huge_pages, 2117 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); 2118} 2119 2120int hugetlb_report_node_meminfo(int nid, char *buf) 2121{ 2122 struct hstate *h = &default_hstate; 2123 return sprintf(buf, 2124 "Node %d HugePages_Total: %5u\n" 2125 "Node %d HugePages_Free: %5u\n" 2126 "Node %d HugePages_Surp: %5u\n", 2127 nid, h->nr_huge_pages_node[nid], 2128 nid, h->free_huge_pages_node[nid], 2129 nid, h->surplus_huge_pages_node[nid]); 2130} 2131 2132/* Return the number pages of memory we physically have, in PAGE_SIZE units. */ 2133unsigned long hugetlb_total_pages(void) 2134{ 2135 struct hstate *h = &default_hstate; 2136 return h->nr_huge_pages * pages_per_huge_page(h); 2137} 2138 2139static int hugetlb_acct_memory(struct hstate *h, long delta) 2140{ 2141 int ret = -ENOMEM; 2142 2143 spin_lock(&hugetlb_lock); 2144 /* 2145 * When cpuset is configured, it breaks the strict hugetlb page 2146 * reservation as the accounting is done on a global variable. Such 2147 * reservation is completely rubbish in the presence of cpuset because 2148 * the reservation is not checked against page availability for the 2149 * current cpuset. Application can still potentially OOM'ed by kernel 2150 * with lack of free htlb page in cpuset that the task is in. 2151 * Attempt to enforce strict accounting with cpuset is almost 2152 * impossible (or too ugly) because cpuset is too fluid that 2153 * task or memory node can be dynamically moved between cpusets. 2154 * 2155 * The change of semantics for shared hugetlb mapping with cpuset is 2156 * undesirable. However, in order to preserve some of the semantics, 2157 * we fall back to check against current free page availability as 2158 * a best attempt and hopefully to minimize the impact of changing 2159 * semantics that cpuset has. 2160 */ 2161 if (delta > 0) { 2162 if (gather_surplus_pages(h, delta) < 0) 2163 goto out; 2164 2165 if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { 2166 return_unused_surplus_pages(h, delta); 2167 goto out; 2168 } 2169 } 2170 2171 ret = 0; 2172 if (delta < 0) 2173 return_unused_surplus_pages(h, (unsigned long) -delta); 2174 2175out: 2176 spin_unlock(&hugetlb_lock); 2177 return ret; 2178} 2179 2180static void hugetlb_vm_op_open(struct vm_area_struct *vma) 2181{ 2182 struct resv_map *reservations = vma_resv_map(vma); 2183 2184 /* 2185 * This new VMA should share its siblings reservation map if present. 2186 * The VMA will only ever have a valid reservation map pointer where 2187 * it is being copied for another still existing VMA. As that VMA 2188 * has a reference to the reservation map it cannot disappear until 2189 * after this open call completes. It is therefore safe to take a 2190 * new reference here without additional locking. 2191 */ 2192 if (reservations) 2193 kref_get(&reservations->refs); 2194} 2195 2196static void resv_map_put(struct vm_area_struct *vma) 2197{ 2198 struct resv_map *reservations = vma_resv_map(vma); 2199 2200 if (!reservations) 2201 return; 2202 kref_put(&reservations->refs, resv_map_release); 2203} 2204 2205static void hugetlb_vm_op_close(struct vm_area_struct *vma) 2206{ 2207 struct hstate *h = hstate_vma(vma); 2208 struct resv_map *reservations = vma_resv_map(vma); 2209 struct hugepage_subpool *spool = subpool_vma(vma); 2210 unsigned long reserve; 2211 unsigned long start; 2212 unsigned long end; 2213 2214 if (reservations) { 2215 start = vma_hugecache_offset(h, vma, vma->vm_start); 2216 end = vma_hugecache_offset(h, vma, vma->vm_end); 2217 2218 reserve = (end - start) - 2219 region_count(&reservations->regions, start, end); 2220 2221 resv_map_put(vma); 2222 2223 if (reserve) { 2224 hugetlb_acct_memory(h, -reserve); 2225 hugepage_subpool_put_pages(spool, reserve); 2226 } 2227 } 2228} 2229 2230/* 2231 * We cannot handle pagefaults against hugetlb pages at all. They cause 2232 * handle_mm_fault() to try to instantiate regular-sized pages in the 2233 * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get 2234 * this far. 2235 */ 2236static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 2237{ 2238 BUG(); 2239 return 0; 2240} 2241 2242const struct vm_operations_struct hugetlb_vm_ops = { 2243 .fault = hugetlb_vm_op_fault, 2244 .open = hugetlb_vm_op_open, 2245 .close = hugetlb_vm_op_close, 2246}; 2247 2248static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, 2249 int writable) 2250{ 2251 pte_t entry; 2252 2253 if (writable) { 2254 entry = 2255 pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); 2256 } else { 2257 entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); 2258 } 2259 entry = pte_mkyoung(entry); 2260 entry = pte_mkhuge(entry); 2261 entry = arch_make_huge_pte(entry, vma, page, writable); 2262 2263 return entry; 2264} 2265 2266static void set_huge_ptep_writable(struct vm_area_struct *vma, 2267 unsigned long address, pte_t *ptep) 2268{ 2269 pte_t entry; 2270 2271 entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); 2272 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) 2273 update_mmu_cache(vma, address, ptep); 2274} 2275 2276 2277int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, 2278 struct vm_area_struct *vma) 2279{ 2280 pte_t *src_pte, *dst_pte, entry; 2281 struct page *ptepage; 2282 unsigned long addr; 2283 int cow; 2284 struct hstate *h = hstate_vma(vma); 2285 unsigned long sz = huge_page_size(h); 2286 2287 cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 2288 2289 for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { 2290 src_pte = huge_pte_offset(src, addr); 2291 if (!src_pte) 2292 continue; 2293 dst_pte = huge_pte_alloc(dst, addr, sz); 2294 if (!dst_pte) 2295 goto nomem; 2296 2297 /* If the pagetables are shared don't copy or take references */ 2298 if (dst_pte == src_pte) 2299 continue; 2300 2301 spin_lock(&dst->page_table_lock); 2302 spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); 2303 if (!huge_pte_none(huge_ptep_get(src_pte))) { 2304 if (cow) 2305 huge_ptep_set_wrprotect(src, addr, src_pte); 2306 entry = huge_ptep_get(src_pte); 2307 ptepage = pte_page(entry); 2308 get_page(ptepage); 2309 page_dup_rmap(ptepage); 2310 set_huge_pte_at(dst, addr, dst_pte, entry); 2311 } 2312 spin_unlock(&src->page_table_lock); 2313 spin_unlock(&dst->page_table_lock); 2314 } 2315 return 0; 2316 2317nomem: 2318 return -ENOMEM; 2319} 2320 2321static int is_hugetlb_entry_migration(pte_t pte) 2322{ 2323 swp_entry_t swp; 2324 2325 if (huge_pte_none(pte) || pte_present(pte)) 2326 return 0; 2327 swp = pte_to_swp_entry(pte); 2328 if (non_swap_entry(swp) && is_migration_entry(swp)) 2329 return 1; 2330 else 2331 return 0; 2332} 2333 2334static int is_hugetlb_entry_hwpoisoned(pte_t pte) 2335{ 2336 swp_entry_t swp; 2337 2338 if (huge_pte_none(pte) || pte_present(pte)) 2339 return 0; 2340 swp = pte_to_swp_entry(pte); 2341 if (non_swap_entry(swp) && is_hwpoison_entry(swp)) 2342 return 1; 2343 else 2344 return 0; 2345} 2346 2347void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 2348 unsigned long start, unsigned long end, 2349 struct page *ref_page) 2350{ 2351 int force_flush = 0; 2352 struct mm_struct *mm = vma->vm_mm; 2353 unsigned long address; 2354 pte_t *ptep; 2355 pte_t pte; 2356 struct page *page; 2357 struct hstate *h = hstate_vma(vma); 2358 unsigned long sz = huge_page_size(h); 2359 2360 WARN_ON(!is_vm_hugetlb_page(vma)); 2361 BUG_ON(start & ~huge_page_mask(h)); 2362 BUG_ON(end & ~huge_page_mask(h)); 2363 2364 tlb_start_vma(tlb, vma); 2365 mmu_notifier_invalidate_range_start(mm, start, end); 2366again: 2367 spin_lock(&mm->page_table_lock); 2368 for (address = start; address < end; address += sz) { 2369 ptep = huge_pte_offset(mm, address); 2370 if (!ptep) 2371 continue; 2372 2373 if (huge_pmd_unshare(mm, &address, ptep)) 2374 continue; 2375 2376 pte = huge_ptep_get(ptep); 2377 if (huge_pte_none(pte)) 2378 continue; 2379 2380 /* 2381 * HWPoisoned hugepage is already unmapped and dropped reference 2382 */ 2383 if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) 2384 continue; 2385 2386 page = pte_page(pte); 2387 /* 2388 * If a reference page is supplied, it is because a specific 2389 * page is being unmapped, not a range. Ensure the page we 2390 * are about to unmap is the actual page of interest. 2391 */ 2392 if (ref_page) { 2393 if (page != ref_page) 2394 continue; 2395 2396 /* 2397 * Mark the VMA as having unmapped its page so that 2398 * future faults in this VMA will fail rather than 2399 * looking like data was lost 2400 */ 2401 set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); 2402 } 2403 2404 pte = huge_ptep_get_and_clear(mm, address, ptep); 2405 tlb_remove_tlb_entry(tlb, ptep, address); 2406 if (pte_dirty(pte)) 2407 set_page_dirty(page); 2408 2409 page_remove_rmap(page); 2410 force_flush = !__tlb_remove_page(tlb, page); 2411 if (force_flush) 2412 break; 2413 /* Bail out after unmapping reference page if supplied */ 2414 if (ref_page) 2415 break; 2416 } 2417 spin_unlock(&mm->page_table_lock); 2418 /* 2419 * mmu_gather ran out of room to batch pages, we break out of 2420 * the PTE lock to avoid doing the potential expensive TLB invalidate 2421 * and page-free while holding it. 2422 */ 2423 if (force_flush) { 2424 force_flush = 0; 2425 tlb_flush_mmu(tlb); 2426 if (address < end && !ref_page) 2427 goto again; 2428 } 2429 mmu_notifier_invalidate_range_end(mm, start, end); 2430 tlb_end_vma(tlb, vma); 2431} 2432 2433void __unmap_hugepage_range_final(struct mmu_gather *tlb, 2434 struct vm_area_struct *vma, unsigned long start, 2435 unsigned long end, struct page *ref_page) 2436{ 2437 __unmap_hugepage_range(tlb, vma, start, end, ref_page); 2438 2439 /* 2440 * Clear this flag so that x86's huge_pmd_share page_table_shareable 2441 * test will fail on a vma being torn down, and not grab a page table 2442 * on its way out. We're lucky that the flag has such an appropriate 2443 * name, and can in fact be safely cleared here. We could clear it 2444 * before the __unmap_hugepage_range above, but all that's necessary 2445 * is to clear it before releasing the i_mmap_mutex. This works 2446 * because in the context this is called, the VMA is about to be 2447 * destroyed and the i_mmap_mutex is held. 2448 */ 2449 vma->vm_flags &= ~VM_MAYSHARE; 2450} 2451 2452void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, 2453 unsigned long end, struct page *ref_page) 2454{ 2455 struct mm_struct *mm; 2456 struct mmu_gather tlb; 2457 2458 mm = vma->vm_mm; 2459 2460 tlb_gather_mmu(&tlb, mm, 0); 2461 __unmap_hugepage_range(&tlb, vma, start, end, ref_page); 2462 tlb_finish_mmu(&tlb, start, end); 2463} 2464 2465/* 2466 * This is called when the original mapper is failing to COW a MAP_PRIVATE 2467 * mappping it owns the reserve page for. The intention is to unmap the page 2468 * from other VMAs and let the children be SIGKILLed if they are faulting the 2469 * same region. 2470 */ 2471static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, 2472 struct page *page, unsigned long address) 2473{ 2474 struct hstate *h = hstate_vma(vma); 2475 struct vm_area_struct *iter_vma; 2476 struct address_space *mapping; 2477 pgoff_t pgoff; 2478 2479 /* 2480 * vm_pgoff is in PAGE_SIZE units, hence the different calculation 2481 * from page cache lookup which is in HPAGE_SIZE units. 2482 */ 2483 address = address & huge_page_mask(h); 2484 pgoff = vma_hugecache_offset(h, vma, address); 2485 mapping = vma->vm_file->f_dentry->d_inode->i_mapping; 2486 2487 /* 2488 * Take the mapping lock for the duration of the table walk. As 2489 * this mapping should be shared between all the VMAs, 2490 * __unmap_hugepage_range() is called as the lock is already held 2491 */ 2492 mutex_lock(&mapping->i_mmap_mutex); 2493 vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { 2494 /* Do not unmap the current VMA */ 2495 if (iter_vma == vma) 2496 continue; 2497 2498 /* 2499 * Unmap the page from other VMAs without their own reserves. 2500 * They get marked to be SIGKILLed if they fault in these 2501 * areas. This is because a future no-page fault on this VMA 2502 * could insert a zeroed page instead of the data existing 2503 * from the time of fork. This would look like data corruption 2504 */ 2505 if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) 2506 unmap_hugepage_range(iter_vma, address, 2507 address + huge_page_size(h), page); 2508 } 2509 mutex_unlock(&mapping->i_mmap_mutex); 2510 2511 return 1; 2512} 2513 2514/* 2515 * Hugetlb_cow() should be called with page lock of the original hugepage held. 2516 * Called with hugetlb_instantiation_mutex held and pte_page locked so we 2517 * cannot race with other handlers or page migration. 2518 * Keep the pte_same checks anyway to make transition from the mutex easier. 2519 */ 2520static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, 2521 unsigned long address, pte_t *ptep, pte_t pte, 2522 struct page *pagecache_page) 2523{ 2524 struct hstate *h = hstate_vma(vma); 2525 struct page *old_page, *new_page; 2526 int avoidcopy; 2527 int outside_reserve = 0; 2528 2529 old_page = pte_page(pte); 2530 2531retry_avoidcopy: 2532 /* If no-one else is actually using this page, avoid the copy 2533 * and just make the page writable */ 2534 avoidcopy = (page_mapcount(old_page) == 1); 2535 if (avoidcopy) { 2536 if (PageAnon(old_page)) 2537 page_move_anon_rmap(old_page, vma, address); 2538 set_huge_ptep_writable(vma, address, ptep); 2539 return 0; 2540 } 2541 2542 /* 2543 * If the process that created a MAP_PRIVATE mapping is about to 2544 * perform a COW due to a shared page count, attempt to satisfy 2545 * the allocation without using the existing reserves. The pagecache 2546 * page is used to determine if the reserve at this address was 2547 * consumed or not. If reserves were used, a partial faulted mapping 2548 * at the time of fork() could consume its reserves on COW instead 2549 * of the full address range. 2550 */ 2551 if (!(vma->vm_flags & VM_MAYSHARE) && 2552 is_vma_resv_set(vma, HPAGE_RESV_OWNER) && 2553 old_page != pagecache_page) 2554 outside_reserve = 1; 2555 2556 page_cache_get(old_page); 2557 2558 /* Drop page_table_lock as buddy allocator may be called */ 2559 spin_unlock(&mm->page_table_lock); 2560 new_page = alloc_huge_page(vma, address, outside_reserve); 2561 2562 if (IS_ERR(new_page)) { 2563 long err = PTR_ERR(new_page); 2564 page_cache_release(old_page); 2565 2566 /* 2567 * If a process owning a MAP_PRIVATE mapping fails to COW, 2568 * it is due to references held by a child and an insufficient 2569 * huge page pool. To guarantee the original mappers 2570 * reliability, unmap the page from child processes. The child 2571 * may get SIGKILLed if it later faults. 2572 */ 2573 if (outside_reserve) { 2574 BUG_ON(huge_pte_none(pte)); 2575 if (unmap_ref_private(mm, vma, old_page, address)) { 2576 BUG_ON(huge_pte_none(pte)); 2577 spin_lock(&mm->page_table_lock); 2578 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2579 if (likely(pte_same(huge_ptep_get(ptep), pte))) 2580 goto retry_avoidcopy; 2581 /* 2582 * race occurs while re-acquiring page_table_lock, and 2583 * our job is done. 2584 */ 2585 return 0; 2586 } 2587 WARN_ON_ONCE(1); 2588 } 2589 2590 /* Caller expects lock to be held */ 2591 spin_lock(&mm->page_table_lock); 2592 if (err == -ENOMEM) 2593 return VM_FAULT_OOM; 2594 else 2595 return VM_FAULT_SIGBUS; 2596 } 2597 2598 /* 2599 * When the original hugepage is shared one, it does not have 2600 * anon_vma prepared. 2601 */ 2602 if (unlikely(anon_vma_prepare(vma))) { 2603 page_cache_release(new_page); 2604 page_cache_release(old_page); 2605 /* Caller expects lock to be held */ 2606 spin_lock(&mm->page_table_lock); 2607 return VM_FAULT_OOM; 2608 } 2609 2610 copy_user_huge_page(new_page, old_page, address, vma, 2611 pages_per_huge_page(h)); 2612 __SetPageUptodate(new_page); 2613 2614 /* 2615 * Retake the page_table_lock to check for racing updates 2616 * before the page tables are altered 2617 */ 2618 spin_lock(&mm->page_table_lock); 2619 ptep = huge_pte_offset(mm, address & huge_page_mask(h)); 2620 if (likely(pte_same(huge_ptep_get(ptep), pte))) { 2621 /* Break COW */ 2622 mmu_notifier_invalidate_range_start(mm, 2623 address & huge_page_mask(h), 2624 (address & huge_page_mask(h)) + huge_page_size(h)); 2625 huge_ptep_clear_flush(vma, address, ptep); 2626 set_huge_pte_at(mm, address, ptep, 2627 make_huge_pte(vma, new_page, 1)); 2628 page_remove_rmap(old_page); 2629 hugepage_add_new_anon_rmap(new_page, vma, address); 2630 /* Make the old page be freed below */ 2631 new_page = old_page; 2632 mmu_notifier_invalidate_range_end(mm, 2633 address & huge_page_mask(h), 2634 (address & huge_page_mask(h)) + huge_page_size(h)); 2635 } 2636 page_cache_release(new_page); 2637 page_cache_release(old_page); 2638 return 0; 2639} 2640 2641/* Return the pagecache page at a given address within a VMA */ 2642static struct page *hugetlbfs_pagecache_page(struct hstate *h, 2643 struct vm_area_struct *vma, unsigned long address) 2644{ 2645 struct address_space *mapping; 2646 pgoff_t idx; 2647 2648 mapping = vma->vm_file->f_mapping; 2649 idx = vma_hugecache_offset(h, vma, address); 2650 2651 return find_lock_page(mapping, idx); 2652} 2653 2654/* 2655 * Return whether there is a pagecache page to back given address within VMA. 2656 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. 2657 */ 2658static bool hugetlbfs_pagecache_present(struct hstate *h, 2659 struct vm_area_struct *vma, unsigned long address) 2660{ 2661 struct address_space *mapping; 2662 pgoff_t idx; 2663 struct page *page; 2664 2665 mapping = vma->vm_file->f_mapping; 2666 idx = vma_hugecache_offset(h, vma, address); 2667 2668 page = find_get_page(mapping, idx); 2669 if (page) 2670 put_page(page); 2671 return page != NULL; 2672} 2673 2674static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2675 unsigned long address, pte_t *ptep, unsigned int flags) 2676{ 2677 struct hstate *h = hstate_vma(vma); 2678 int ret = VM_FAULT_SIGBUS; 2679 int anon_rmap = 0; 2680 pgoff_t idx; 2681 unsigned long size; 2682 struct page *page; 2683 struct address_space *mapping; 2684 pte_t new_pte; 2685 2686 /* 2687 * Currently, we are forced to kill the process in the event the 2688 * original mapper has unmapped pages from the child due to a failed 2689 * COW. Warn that such a situation has occurred as it may not be obvious 2690 */ 2691 if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { 2692 printk(KERN_WARNING 2693 "PID %d killed due to inadequate hugepage pool\n", 2694 current->pid); 2695 return ret; 2696 } 2697 2698 mapping = vma->vm_file->f_mapping; 2699 idx = vma_hugecache_offset(h, vma, address); 2700 2701 /* 2702 * Use page lock to guard against racing truncation 2703 * before we get page_table_lock. 2704 */ 2705retry: 2706 page = find_lock_page(mapping, idx); 2707 if (!page) { 2708 size = i_size_read(mapping->host) >> huge_page_shift(h); 2709 if (idx >= size) 2710 goto out; 2711 page = alloc_huge_page(vma, address, 0); 2712 if (IS_ERR(page)) { 2713 ret = PTR_ERR(page); 2714 if (ret == -ENOMEM) 2715 ret = VM_FAULT_OOM; 2716 else 2717 ret = VM_FAULT_SIGBUS; 2718 goto out; 2719 } 2720 clear_huge_page(page, address, pages_per_huge_page(h)); 2721 __SetPageUptodate(page); 2722 2723 if (vma->vm_flags & VM_MAYSHARE) { 2724 int err; 2725 struct inode *inode = mapping->host; 2726 2727 err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); 2728 if (err) { 2729 put_page(page); 2730 if (err == -EEXIST) 2731 goto retry; 2732 goto out; 2733 } 2734 2735 spin_lock(&inode->i_lock); 2736 inode->i_blocks += blocks_per_huge_page(h); 2737 spin_unlock(&inode->i_lock); 2738 } else { 2739 lock_page(page); 2740 if (unlikely(anon_vma_prepare(vma))) { 2741 ret = VM_FAULT_OOM; 2742 goto backout_unlocked; 2743 } 2744 anon_rmap = 1; 2745 } 2746 } else { 2747 /* 2748 * If memory error occurs between mmap() and fault, some process 2749 * don't have hwpoisoned swap entry for errored virtual address. 2750 * So we need to block hugepage fault by PG_hwpoison bit check. 2751 */ 2752 if (unlikely(PageHWPoison(page))) { 2753 ret = VM_FAULT_HWPOISON | 2754 VM_FAULT_SET_HINDEX(hstate_index(h)); 2755 goto backout_unlocked; 2756 } 2757 } 2758 2759 /* 2760 * If we are going to COW a private mapping later, we examine the 2761 * pending reservations for this page now. This will ensure that 2762 * any allocations necessary to record that reservation occur outside 2763 * the spinlock. 2764 */ 2765 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) 2766 if (vma_needs_reservation(h, vma, address) < 0) { 2767 ret = VM_FAULT_OOM; 2768 goto backout_unlocked; 2769 } 2770 2771 spin_lock(&mm->page_table_lock); 2772 size = i_size_read(mapping->host) >> huge_page_shift(h); 2773 if (idx >= size) 2774 goto backout; 2775 2776 ret = 0; 2777 if (!huge_pte_none(huge_ptep_get(ptep))) 2778 goto backout; 2779 2780 if (anon_rmap) 2781 hugepage_add_new_anon_rmap(page, vma, address); 2782 else 2783 page_dup_rmap(page); 2784 new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) 2785 && (vma->vm_flags & VM_SHARED))); 2786 set_huge_pte_at(mm, address, ptep, new_pte); 2787 2788 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { 2789 /* Optimization, do the COW without a second fault */ 2790 ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); 2791 } 2792 2793 spin_unlock(&mm->page_table_lock); 2794 unlock_page(page); 2795out: 2796 return ret; 2797 2798backout: 2799 spin_unlock(&mm->page_table_lock); 2800backout_unlocked: 2801 unlock_page(page); 2802 put_page(page); 2803 goto out; 2804} 2805 2806int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2807 unsigned long address, unsigned int flags) 2808{ 2809 pte_t *ptep; 2810 pte_t entry; 2811 int ret; 2812 struct page *page = NULL; 2813 struct page *pagecache_page = NULL; 2814 static DEFINE_MUTEX(hugetlb_instantiation_mutex); 2815 struct hstate *h = hstate_vma(vma); 2816 2817 address &= huge_page_mask(h); 2818 2819 ptep = huge_pte_offset(mm, address); 2820 if (ptep) { 2821 entry = huge_ptep_get(ptep); 2822 if (unlikely(is_hugetlb_entry_migration(entry))) { 2823 migration_entry_wait(mm, (pmd_t *)ptep, address); 2824 return 0; 2825 } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) 2826 return VM_FAULT_HWPOISON_LARGE | 2827 VM_FAULT_SET_HINDEX(hstate_index(h)); 2828 } 2829 2830 ptep = huge_pte_alloc(mm, address, huge_page_size(h)); 2831 if (!ptep) 2832 return VM_FAULT_OOM; 2833 2834 /* 2835 * Serialize hugepage allocation and instantiation, so that we don't 2836 * get spurious allocation failures if two CPUs race to instantiate 2837 * the same page in the page cache. 2838 */ 2839 mutex_lock(&hugetlb_instantiation_mutex); 2840 entry = huge_ptep_get(ptep); 2841 if (huge_pte_none(entry)) { 2842 ret = hugetlb_no_page(mm, vma, address, ptep, flags); 2843 goto out_mutex; 2844 } 2845 2846 ret = 0; 2847 2848 /* 2849 * If we are going to COW the mapping later, we examine the pending 2850 * reservations for this page now. This will ensure that any 2851 * allocations necessary to record that reservation occur outside the 2852 * spinlock. For private mappings, we also lookup the pagecache 2853 * page now as it is used to determine if a reservation has been 2854 * consumed. 2855 */ 2856 if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) { 2857 if (vma_needs_reservation(h, vma, address) < 0) { 2858 ret = VM_FAULT_OOM; 2859 goto out_mutex; 2860 } 2861 2862 if (!(vma->vm_flags & VM_MAYSHARE)) 2863 pagecache_page = hugetlbfs_pagecache_page(h, 2864 vma, address); 2865 } 2866 2867 /* 2868 * hugetlb_cow() requires page locks of pte_page(entry) and 2869 * pagecache_page, so here we need take the former one 2870 * when page != pagecache_page or !pagecache_page. 2871 * Note that locking order is always pagecache_page -> page, 2872 * so no worry about deadlock. 2873 */ 2874 page = pte_page(entry); 2875 get_page(page); 2876 if (page != pagecache_page) 2877 lock_page(page); 2878 2879 spin_lock(&mm->page_table_lock); 2880 /* Check for a racing update before calling hugetlb_cow */ 2881 if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) 2882 goto out_page_table_lock; 2883 2884 2885 if (flags & FAULT_FLAG_WRITE) { 2886 if (!pte_write(entry)) { 2887 ret = hugetlb_cow(mm, vma, address, ptep, entry, 2888 pagecache_page); 2889 goto out_page_table_lock; 2890 } 2891 entry = pte_mkdirty(entry); 2892 } 2893 entry = pte_mkyoung(entry); 2894 if (huge_ptep_set_access_flags(vma, address, ptep, entry, 2895 flags & FAULT_FLAG_WRITE)) 2896 update_mmu_cache(vma, address, ptep); 2897 2898out_page_table_lock: 2899 spin_unlock(&mm->page_table_lock); 2900 2901 if (pagecache_page) { 2902 unlock_page(pagecache_page); 2903 put_page(pagecache_page); 2904 } 2905 if (page != pagecache_page) 2906 unlock_page(page); 2907 put_page(page); 2908 2909out_mutex: 2910 mutex_unlock(&hugetlb_instantiation_mutex); 2911 2912 return ret; 2913} 2914 2915/* Can be overriden by architectures */ 2916__attribute__((weak)) struct page * 2917follow_huge_pud(struct mm_struct *mm, unsigned long address, 2918 pud_t *pud, int write) 2919{ 2920 BUG(); 2921 return NULL; 2922} 2923 2924int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 2925 struct page **pages, struct vm_area_struct **vmas, 2926 unsigned long *position, int *length, int i, 2927 unsigned int flags) 2928{ 2929 unsigned long pfn_offset; 2930 unsigned long vaddr = *position; 2931 int remainder = *length; 2932 struct hstate *h = hstate_vma(vma); 2933 2934 spin_lock(&mm->page_table_lock); 2935 while (vaddr < vma->vm_end && remainder) { 2936 pte_t *pte; 2937 int absent; 2938 struct page *page; 2939 2940 /* 2941 * Some archs (sparc64, sh*) have multiple pte_ts to 2942 * each hugepage. We have to make sure we get the 2943 * first, for the page indexing below to work. 2944 */ 2945 pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); 2946 absent = !pte || huge_pte_none(huge_ptep_get(pte)); 2947 2948 /* 2949 * When coredumping, it suits get_dump_page if we just return 2950 * an error where there's an empty slot with no huge pagecache 2951 * to back it. This way, we avoid allocating a hugepage, and 2952 * the sparse dumpfile avoids allocating disk blocks, but its 2953 * huge holes still show up with zeroes where they need to be. 2954 */ 2955 if (absent && (flags & FOLL_DUMP) && 2956 !hugetlbfs_pagecache_present(h, vma, vaddr)) { 2957 remainder = 0; 2958 break; 2959 } 2960 2961 if (absent || 2962 ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) { 2963 int ret; 2964 2965 spin_unlock(&mm->page_table_lock); 2966 ret = hugetlb_fault(mm, vma, vaddr, 2967 (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); 2968 spin_lock(&mm->page_table_lock); 2969 if (!(ret & VM_FAULT_ERROR)) 2970 continue; 2971 2972 remainder = 0; 2973 break; 2974 } 2975 2976 pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; 2977 page = pte_page(huge_ptep_get(pte)); 2978same_page: 2979 if (pages) { 2980 pages[i] = mem_map_offset(page, pfn_offset); 2981 get_page(pages[i]); 2982 } 2983 2984 if (vmas) 2985 vmas[i] = vma; 2986 2987 vaddr += PAGE_SIZE; 2988 ++pfn_offset; 2989 --remainder; 2990 ++i; 2991 if (vaddr < vma->vm_end && remainder && 2992 pfn_offset < pages_per_huge_page(h)) { 2993 /* 2994 * We use pfn_offset to avoid touching the pageframes 2995 * of this compound page. 2996 */ 2997 goto same_page; 2998 } 2999 } 3000 spin_unlock(&mm->page_table_lock); 3001 *length = remainder; 3002 *position = vaddr; 3003 3004 return i ? i : -EFAULT; 3005} 3006 3007void hugetlb_change_protection(struct vm_area_struct *vma, 3008 unsigned long address, unsigned long end, pgprot_t newprot) 3009{ 3010 struct mm_struct *mm = vma->vm_mm; 3011 unsigned long start = address; 3012 pte_t *ptep; 3013 pte_t pte; 3014 struct hstate *h = hstate_vma(vma); 3015 3016 BUG_ON(address >= end); 3017 flush_cache_range(vma, address, end); 3018 3019 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); 3020 spin_lock(&mm->page_table_lock); 3021 for (; address < end; address += huge_page_size(h)) { 3022 ptep = huge_pte_offset(mm, address); 3023 if (!ptep) 3024 continue; 3025 if (huge_pmd_unshare(mm, &address, ptep)) 3026 continue; 3027 if (!huge_pte_none(huge_ptep_get(ptep))) { 3028 pte = huge_ptep_get_and_clear(mm, address, ptep); 3029 pte = pte_mkhuge(pte_modify(pte, newprot)); 3030 set_huge_pte_at(mm, address, ptep, pte); 3031 } 3032 } 3033 spin_unlock(&mm->page_table_lock); 3034 /* 3035 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare 3036 * may have cleared our pud entry and done put_page on the page table: 3037 * once we release i_mmap_mutex, another task can do the final put_page 3038 * and that page table be reused and filled with junk. 3039 */ 3040 flush_tlb_range(vma, start, end); 3041 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); 3042} 3043 3044int hugetlb_reserve_pages(struct inode *inode, 3045 long from, long to, 3046 struct vm_area_struct *vma, 3047 vm_flags_t vm_flags) 3048{ 3049 long ret, chg; 3050 struct hstate *h = hstate_inode(inode); 3051 struct hugepage_subpool *spool = subpool_inode(inode); 3052 3053 /* 3054 * Only apply hugepage reservation if asked. At fault time, an 3055 * attempt will be made for VM_NORESERVE to allocate a page 3056 * without using reserves 3057 */ 3058 if (vm_flags & VM_NORESERVE) 3059 return 0; 3060 3061 /* 3062 * Shared mappings base their reservation on the number of pages that 3063 * are already allocated on behalf of the file. Private mappings need 3064 * to reserve the full area even if read-only as mprotect() may be 3065 * called to make the mapping read-write. Assume !vma is a shm mapping 3066 */ 3067 if (!vma || vma->vm_flags & VM_MAYSHARE) 3068 chg = region_chg(&inode->i_mapping->private_list, from, to); 3069 else { 3070 struct resv_map *resv_map = resv_map_alloc(); 3071 if (!resv_map) 3072 return -ENOMEM; 3073 3074 chg = to - from; 3075 3076 set_vma_resv_map(vma, resv_map); 3077 set_vma_resv_flags(vma, HPAGE_RESV_OWNER); 3078 } 3079 3080 if (chg < 0) { 3081 ret = chg; 3082 goto out_err; 3083 } 3084 3085 /* There must be enough pages in the subpool for the mapping */ 3086 if (hugepage_subpool_get_pages(spool, chg)) { 3087 ret = -ENOSPC; 3088 goto out_err; 3089 } 3090 3091 /* 3092 * Check enough hugepages are available for the reservation. 3093 * Hand the pages back to the subpool if there are not 3094 */ 3095 ret = hugetlb_acct_memory(h, chg); 3096 if (ret < 0) { 3097 hugepage_subpool_put_pages(spool, chg); 3098 goto out_err; 3099 } 3100 3101 /* 3102 * Account for the reservations made. Shared mappings record regions 3103 * that have reservations as they are shared by multiple VMAs. 3104 * When the last VMA disappears, the region map says how much 3105 * the reservation was and the page cache tells how much of 3106 * the reservation was consumed. Private mappings are per-VMA and 3107 * only the consumed reservations are tracked. When the VMA 3108 * disappears, the original reservation is the VMA size and the 3109 * consumed reservations are stored in the map. Hence, nothing 3110 * else has to be done for private mappings here 3111 */ 3112 if (!vma || vma->vm_flags & VM_MAYSHARE) 3113 region_add(&inode->i_mapping->private_list, from, to); 3114 return 0; 3115out_err: 3116 if (vma) 3117 resv_map_put(vma); 3118 return ret; 3119} 3120 3121void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) 3122{ 3123 struct hstate *h = hstate_inode(inode); 3124 long chg = region_truncate(&inode->i_mapping->private_list, offset); 3125 struct hugepage_subpool *spool = subpool_inode(inode); 3126 3127 spin_lock(&inode->i_lock); 3128 inode->i_blocks -= (blocks_per_huge_page(h) * freed); 3129 spin_unlock(&inode->i_lock); 3130 3131 hugepage_subpool_put_pages(spool, (chg - freed)); 3132 hugetlb_acct_memory(h, -(chg - freed)); 3133} 3134 3135#ifdef CONFIG_MEMORY_FAILURE 3136 3137/* Should be called in hugetlb_lock */ 3138static int is_hugepage_on_freelist(struct page *hpage) 3139{ 3140 struct page *page; 3141 struct page *tmp; 3142 struct hstate *h = page_hstate(hpage); 3143 int nid = page_to_nid(hpage); 3144 3145 list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) 3146 if (page == hpage) 3147 return 1; 3148 return 0; 3149} 3150 3151/* 3152 * This function is called from memory failure code. 3153 * Assume the caller holds page lock of the head page. 3154 */ 3155int dequeue_hwpoisoned_huge_page(struct page *hpage) 3156{ 3157 struct hstate *h = page_hstate(hpage); 3158 int nid = page_to_nid(hpage); 3159 int ret = -EBUSY; 3160 3161 spin_lock(&hugetlb_lock); 3162 if (is_hugepage_on_freelist(hpage)) { 3163 list_del(&hpage->lru); 3164 set_page_refcounted(hpage); 3165 h->free_huge_pages--; 3166 h->free_huge_pages_node[nid]--; 3167 ret = 0; 3168 } 3169 spin_unlock(&hugetlb_lock); 3170 return ret; 3171} 3172#endif 3173