1/*
   2 * Generic hugetlb support.
   3 * (C) Nadia Yvette Chambers, April 2004
   4 */
   5#include <linux/list.h>
   6#include <linux/init.h>
   7#include <linux/module.h>
   8#include <linux/mm.h>
   9#include <linux/seq_file.h>
  10#include <linux/sysctl.h>
  11#include <linux/highmem.h>
  12#include <linux/mmu_notifier.h>
  13#include <linux/nodemask.h>
  14#include <linux/pagemap.h>
  15#include <linux/mempolicy.h>
  16#include <linux/compiler.h>
  17#include <linux/cpuset.h>
  18#include <linux/mutex.h>
  19#include <linux/bootmem.h>
  20#include <linux/sysfs.h>
  21#include <linux/slab.h>
 
 
 
  22#include <linux/rmap.h>
 
  23#include <linux/swap.h>
  24#include <linux/swapops.h>
  25#include <linux/page-isolation.h>
  26#include <linux/jhash.h>
 
 
 
 
 
 
 
 
 
  27
  28#include <asm/page.h>
  29#include <asm/pgtable.h>
  30#include <asm/tlb.h>
  31
  32#include <linux/io.h>
  33#include <linux/hugetlb.h>
  34#include <linux/hugetlb_cgroup.h>
  35#include <linux/node.h>
 
  36#include "internal.h"
  37
  38const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
  39unsigned long hugepages_treat_as_movable;
  40
  41int hugetlb_max_hstate __read_mostly;
  42unsigned int default_hstate_idx;
  43struct hstate hstates[HUGE_MAX_HSTATE];
  44
  45__initdata LIST_HEAD(huge_boot_pages);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  46
  47/* for command line parsing */
  48static struct hstate * __initdata parsed_hstate;
  49static unsigned long __initdata default_hstate_max_huge_pages;
  50static unsigned long __initdata default_hstate_size;
 
 
  51
  52/*
  53 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
  54 * free_huge_pages, and surplus_huge_pages.
  55 */
  56DEFINE_SPINLOCK(hugetlb_lock);
  57
  58/*
  59 * Serializes faults on the same logical page.  This is used to
  60 * prevent spurious OOMs when the hugepage pool is fully utilized.
  61 */
  62static int num_fault_mutexes;
  63static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp;
  64
  65static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
 
 
 
 
 
 
 
 
 
  66{
  67	bool free = (spool->count == 0) && (spool->used_hpages == 0);
 
 
 
 
 
  68
  69	spin_unlock(&spool->lock);
 
 
 
 
 
 
  70
  71	/* If no pages are used, and no other handles to the subpool
  72	 * remain, free the subpool the subpool remain */
  73	if (free)
 
 
 
 
  74		kfree(spool);
 
  75}
  76
  77struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
 
  78{
  79	struct hugepage_subpool *spool;
  80
  81	spool = kmalloc(sizeof(*spool), GFP_KERNEL);
  82	if (!spool)
  83		return NULL;
  84
  85	spin_lock_init(&spool->lock);
  86	spool->count = 1;
  87	spool->max_hpages = nr_blocks;
  88	spool->used_hpages = 0;
 
 
 
 
 
 
 
  89
  90	return spool;
  91}
  92
  93void hugepage_put_subpool(struct hugepage_subpool *spool)
  94{
  95	spin_lock(&spool->lock);
 
 
  96	BUG_ON(!spool->count);
  97	spool->count--;
  98	unlock_or_release_subpool(spool);
  99}
 100
 101static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
 
 
 
 
 
 
 
 
 102				      long delta)
 103{
 104	int ret = 0;
 105
 106	if (!spool)
 107		return 0;
 108
 109	spin_lock(&spool->lock);
 110	if ((spool->used_hpages + delta) <= spool->max_hpages) {
 111		spool->used_hpages += delta;
 112	} else {
 113		ret = -ENOMEM;
 
 
 
 
 114	}
 115	spin_unlock(&spool->lock);
 116
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 117	return ret;
 118}
 119
 120static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
 
 
 
 
 
 
 121				       long delta)
 122{
 
 
 
 123	if (!spool)
 124		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 125
 126	spin_lock(&spool->lock);
 127	spool->used_hpages -= delta;
 128	/* If hugetlbfs_put_super couldn't free spool due to
 129	* an outstanding quota reference, free it now. */
 130	unlock_or_release_subpool(spool);
 
 
 131}
 132
 133static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
 134{
 135	return HUGETLBFS_SB(inode->i_sb)->spool;
 136}
 137
 138static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
 139{
 140	return subpool_inode(file_inode(vma->vm_file));
 141}
 142
 143/*
 144 * Region tracking -- allows tracking of reservations and instantiated pages
 145 *                    across the pages in a mapping.
 146 *
 147 * The region data structures are embedded into a resv_map and
 148 * protected by a resv_map's lock
 149 */
 150struct file_region {
 151	struct list_head link;
 152	long from;
 153	long to;
 154};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 155
 156static long region_add(struct resv_map *resv, long f, long t)
 157{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 158	struct list_head *head = &resv->regions;
 159	struct file_region *rg, *nrg, *trg;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 160
 161	spin_lock(&resv->lock);
 162	/* Locate the region we are either in or before. */
 163	list_for_each_entry(rg, head, link)
 164		if (f <= rg->to)
 
 165			break;
 
 166
 167	/* Round our left edge to the current segment if it encloses us. */
 168	if (f > rg->from)
 169		f = rg->from;
 
 
 
 
 
 170
 171	/* Check for and consume any regions we now overlap with. */
 172	nrg = rg;
 173	list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
 174		if (&rg->link == head)
 175			break;
 176		if (rg->from > t)
 177			break;
 178
 179		/* If this area reaches higher then extend our area to
 180		 * include it completely.  If this is not the first area
 181		 * which we intend to reuse, free it. */
 182		if (rg->to > t)
 183			t = rg->to;
 184		if (rg != nrg) {
 185			list_del(&rg->link);
 186			kfree(rg);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 187		}
 
 
 
 
 
 188	}
 189	nrg->from = f;
 190	nrg->to = t;
 191	spin_unlock(&resv->lock);
 192	return 0;
 
 
 
 
 
 
 
 193}
 194
 195static long region_chg(struct resv_map *resv, long f, long t)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 196{
 197	struct list_head *head = &resv->regions;
 198	struct file_region *rg, *nrg = NULL;
 199	long chg = 0;
 200
 201retry:
 202	spin_lock(&resv->lock);
 203	/* Locate the region we are before or in. */
 204	list_for_each_entry(rg, head, link)
 205		if (f <= rg->to)
 206			break;
 207
 208	/* If we are below the current region then a new region is required.
 209	 * Subtle, allocate a new region at the position but make it zero
 210	 * size such that we can guarantee to record the reservation. */
 211	if (&rg->link == head || t < rg->from) {
 212		if (!nrg) {
 213			spin_unlock(&resv->lock);
 214			nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
 215			if (!nrg)
 216				return -ENOMEM;
 217
 218			nrg->from = f;
 219			nrg->to   = f;
 220			INIT_LIST_HEAD(&nrg->link);
 221			goto retry;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 222		}
 223
 224		list_add(&nrg->link, rg->link.prev);
 225		chg = t - f;
 226		goto out_nrg;
 227	}
 228
 229	/* Round our left edge to the current segment if it encloses us. */
 230	if (f > rg->from)
 231		f = rg->from;
 232	chg = t - f;
 233
 234	/* Check for and consume any regions we now overlap with. */
 235	list_for_each_entry(rg, rg->link.prev, link) {
 236		if (&rg->link == head)
 237			break;
 238		if (rg->from > t)
 239			goto out;
 240
 241		/* We overlap with this area, if it extends further than
 242		 * us then we must extend ourselves.  Account for its
 243		 * existing reservation. */
 244		if (rg->to > t) {
 245			chg += rg->to - t;
 246			t = rg->to;
 247		}
 248		chg -= rg->to - rg->from;
 249	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 250
 251out:
 252	spin_unlock(&resv->lock);
 253	/*  We already know we raced and no longer need the new region */
 254	kfree(nrg);
 255	return chg;
 256out_nrg:
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 257	spin_unlock(&resv->lock);
 258	return chg;
 259}
 260
 261static long region_truncate(struct resv_map *resv, long end)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 262{
 263	struct list_head *head = &resv->regions;
 264	struct file_region *rg, *trg;
 265	long chg = 0;
 
 266
 
 267	spin_lock(&resv->lock);
 268	/* Locate the region we are either in or before. */
 269	list_for_each_entry(rg, head, link)
 270		if (end <= rg->to)
 
 
 
 
 
 
 
 
 
 271			break;
 272	if (&rg->link == head)
 273		goto out;
 274
 275	/* If we are in the middle of a region then adjust it. */
 276	if (end > rg->from) {
 277		chg = rg->to - end;
 278		rg->to = end;
 279		rg = list_entry(rg->link.next, typeof(*rg), link);
 280	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 281
 282	/* Drop any remaining regions. */
 283	list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
 284		if (&rg->link == head)
 
 
 285			break;
 286		chg += rg->to - rg->from;
 287		list_del(&rg->link);
 288		kfree(rg);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 289	}
 290
 291out:
 292	spin_unlock(&resv->lock);
 293	return chg;
 
 294}
 295
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 296static long region_count(struct resv_map *resv, long f, long t)
 297{
 298	struct list_head *head = &resv->regions;
 299	struct file_region *rg;
 300	long chg = 0;
 301
 302	spin_lock(&resv->lock);
 303	/* Locate each segment we overlap with, and count that overlap. */
 304	list_for_each_entry(rg, head, link) {
 305		long seg_from;
 306		long seg_to;
 307
 308		if (rg->to <= f)
 309			continue;
 310		if (rg->from >= t)
 311			break;
 312
 313		seg_from = max(rg->from, f);
 314		seg_to = min(rg->to, t);
 315
 316		chg += seg_to - seg_from;
 317	}
 318	spin_unlock(&resv->lock);
 319
 320	return chg;
 321}
 322
 323/*
 324 * Convert the address within this vma to the page offset within
 325 * the mapping, in pagecache page units; huge pages here.
 326 */
 327static pgoff_t vma_hugecache_offset(struct hstate *h,
 328			struct vm_area_struct *vma, unsigned long address)
 329{
 330	return ((address - vma->vm_start) >> huge_page_shift(h)) +
 331			(vma->vm_pgoff >> huge_page_order(h));
 332}
 333
 334pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
 335				     unsigned long address)
 336{
 337	return vma_hugecache_offset(hstate_vma(vma), vma, address);
 338}
 339
 340/*
 341 * Return the size of the pages allocated when backing a VMA. In the majority
 342 * cases this will be same size as used by the page table entries.
 343 */
 344unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
 345{
 346	struct hstate *hstate;
 347
 348	if (!is_vm_hugetlb_page(vma))
 349		return PAGE_SIZE;
 350
 351	hstate = hstate_vma(vma);
 352
 353	return 1UL << huge_page_shift(hstate);
 354}
 355EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
 356
 357/*
 358 * Return the page size being used by the MMU to back a VMA. In the majority
 359 * of cases, the page size used by the kernel matches the MMU size. On
 360 * architectures where it differs, an architecture-specific version of this
 361 * function is required.
 362 */
 363#ifndef vma_mmu_pagesize
 364unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
 365{
 366	return vma_kernel_pagesize(vma);
 367}
 368#endif
 369
 370/*
 371 * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
 372 * bits of the reservation map pointer, which are always clear due to
 373 * alignment.
 374 */
 375#define HPAGE_RESV_OWNER    (1UL << 0)
 376#define HPAGE_RESV_UNMAPPED (1UL << 1)
 377#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
 378
 379/*
 380 * These helpers are used to track how many pages are reserved for
 381 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
 382 * is guaranteed to have their future faults succeed.
 383 *
 384 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
 385 * the reserve counters are updated with the hugetlb_lock held. It is safe
 386 * to reset the VMA at fork() time as it is not in use yet and there is no
 387 * chance of the global counters getting corrupted as a result of the values.
 388 *
 389 * The private mapping reservation is represented in a subtly different
 390 * manner to a shared mapping.  A shared mapping has a region map associated
 391 * with the underlying file, this region map represents the backing file
 392 * pages which have ever had a reservation assigned which this persists even
 393 * after the page is instantiated.  A private mapping has a region map
 394 * associated with the original mmap which is attached to all VMAs which
 395 * reference it, this region map represents those offsets which have consumed
 396 * reservation ie. where pages have been instantiated.
 397 */
 398static unsigned long get_vma_private_data(struct vm_area_struct *vma)
 399{
 400	return (unsigned long)vma->vm_private_data;
 401}
 402
 403static void set_vma_private_data(struct vm_area_struct *vma,
 404							unsigned long value)
 405{
 406	vma->vm_private_data = (void *)value;
 407}
 408
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 409struct resv_map *resv_map_alloc(void)
 410{
 411	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
 412	if (!resv_map)
 
 
 
 
 413		return NULL;
 
 414
 415	kref_init(&resv_map->refs);
 416	spin_lock_init(&resv_map->lock);
 417	INIT_LIST_HEAD(&resv_map->regions);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 418
 419	return resv_map;
 420}
 421
 422void resv_map_release(struct kref *ref)
 423{
 424	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
 
 
 425
 426	/* Clear out any active regions before we release the map. */
 427	region_truncate(resv_map, 0);
 
 
 
 
 
 
 
 
 
 428	kfree(resv_map);
 429}
 430
 431static inline struct resv_map *inode_resv_map(struct inode *inode)
 432{
 433	return inode->i_mapping->private_data;
 
 
 
 
 
 
 
 
 434}
 435
 436static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
 437{
 438	VM_BUG_ON(!is_vm_hugetlb_page(vma));
 439	if (vma->vm_flags & VM_MAYSHARE) {
 440		struct address_space *mapping = vma->vm_file->f_mapping;
 441		struct inode *inode = mapping->host;
 442
 443		return inode_resv_map(inode);
 444
 445	} else {
 446		return (struct resv_map *)(get_vma_private_data(vma) &
 447							~HPAGE_RESV_MASK);
 448	}
 449}
 450
 451static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
 452{
 453	VM_BUG_ON(!is_vm_hugetlb_page(vma));
 454	VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
 455
 456	set_vma_private_data(vma, (get_vma_private_data(vma) &
 457				HPAGE_RESV_MASK) | (unsigned long)map);
 458}
 459
 460static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
 461{
 462	VM_BUG_ON(!is_vm_hugetlb_page(vma));
 463	VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
 464
 465	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
 466}
 467
 468static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
 469{
 470	VM_BUG_ON(!is_vm_hugetlb_page(vma));
 471
 472	return (get_vma_private_data(vma) & flag) != 0;
 473}
 474
 475/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
 476void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
 477{
 478	VM_BUG_ON(!is_vm_hugetlb_page(vma));
 479	if (!(vma->vm_flags & VM_MAYSHARE))
 480		vma->vm_private_data = (void *)0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 481}
 482
 483/* Returns true if the VMA has associated reserve pages */
 484static int vma_has_reserves(struct vm_area_struct *vma, long chg)
 485{
 486	if (vma->vm_flags & VM_NORESERVE) {
 487		/*
 488		 * This address is already reserved by other process(chg == 0),
 489		 * so, we should decrement reserved count. Without decrementing,
 490		 * reserve count remains after releasing inode, because this
 491		 * allocated page will go into page cache and is regarded as
 492		 * coming from reserved pool in releasing step.  Currently, we
 493		 * don't have any other solution to deal with this situation
 494		 * properly, so add work-around here.
 495		 */
 496		if (vma->vm_flags & VM_MAYSHARE && chg == 0)
 497			return 1;
 498		else
 499			return 0;
 500	}
 501
 502	/* Shared mappings always use reserves */
 503	if (vma->vm_flags & VM_MAYSHARE)
 504		return 1;
 
 
 
 
 
 
 
 
 
 
 
 505
 506	/*
 507	 * Only the process that called mmap() has reserves for
 508	 * private mappings.
 509	 */
 510	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
 511		return 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 512
 513	return 0;
 514}
 515
 516static void enqueue_huge_page(struct hstate *h, struct page *page)
 517{
 518	int nid = page_to_nid(page);
 519	list_move(&page->lru, &h->hugepage_freelists[nid]);
 
 
 
 
 520	h->free_huge_pages++;
 521	h->free_huge_pages_node[nid]++;
 
 522}
 523
 524static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
 
 525{
 526	struct page *page;
 
 527
 528	list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
 529		if (!is_migrate_isolate_page(page))
 530			break;
 531	/*
 532	 * if 'non-isolated free hugepage' not found on the list,
 533	 * the allocation fails.
 534	 */
 535	if (&h->hugepage_freelists[nid] == &page->lru)
 536		return NULL;
 537	list_move(&page->lru, &h->hugepage_activelist);
 538	set_page_refcounted(page);
 539	h->free_huge_pages--;
 540	h->free_huge_pages_node[nid]--;
 541	return page;
 
 
 
 542}
 543
 544/* Movability of hugepages depends on migration support. */
 545static inline gfp_t htlb_alloc_mask(struct hstate *h)
 546{
 547	if (hugepages_treat_as_movable || hugepage_migration_support(h))
 548		return GFP_HIGHUSER_MOVABLE;
 549	else
 550		return GFP_HIGHUSER;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 551}
 552
 553static struct page *dequeue_huge_page_vma(struct hstate *h,
 
 
 
 
 
 554				struct vm_area_struct *vma,
 555				unsigned long address, int avoid_reserve,
 556				long chg)
 557{
 558	struct page *page = NULL;
 559	struct mempolicy *mpol;
 
 560	nodemask_t *nodemask;
 561	struct zonelist *zonelist;
 562	struct zone *zone;
 563	struct zoneref *z;
 564	unsigned int cpuset_mems_cookie;
 565
 566	/*
 567	 * A child process with MAP_PRIVATE mappings created by their parent
 568	 * have no page reserves. This check ensures that reservations are
 569	 * not "stolen". The child may still get SIGKILLed
 570	 */
 571	if (!vma_has_reserves(vma, chg) &&
 572			h->free_huge_pages - h->resv_huge_pages == 0)
 573		goto err;
 574
 575	/* If reserves cannot be used, ensure enough pages are in the pool */
 576	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
 577		goto err;
 578
 579retry_cpuset:
 580	cpuset_mems_cookie = read_mems_allowed_begin();
 581	zonelist = huge_zonelist(vma, address,
 582					htlb_alloc_mask(h), &mpol, &nodemask);
 583
 584	for_each_zone_zonelist_nodemask(zone, z, zonelist,
 585						MAX_NR_ZONES - 1, nodemask) {
 586		if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) {
 587			page = dequeue_huge_page_node(h, zone_to_nid(zone));
 588			if (page) {
 589				if (avoid_reserve)
 590					break;
 591				if (!vma_has_reserves(vma, chg))
 592					break;
 593
 594				SetPagePrivate(page);
 595				h->resv_huge_pages--;
 596				break;
 597			}
 598		}
 
 
 
 
 
 
 599	}
 600
 601	mpol_cond_put(mpol);
 602	if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
 603		goto retry_cpuset;
 604	return page;
 605
 606err:
 607	return NULL;
 608}
 609
 610static void update_and_free_page(struct hstate *h, struct page *page)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 611{
 612	int i;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 613
 614	VM_BUG_ON(h->order >= MAX_ORDER);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 615
 616	h->nr_huge_pages--;
 617	h->nr_huge_pages_node[page_to_nid(page)]--;
 618	for (i = 0; i < pages_per_huge_page(h); i++) {
 619		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
 620				1 << PG_referenced | 1 << PG_dirty |
 621				1 << PG_active | 1 << PG_reserved |
 622				1 << PG_private | 1 << PG_writeback);
 623	}
 624	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
 625	set_compound_page_dtor(page, NULL);
 626	set_page_refcounted(page);
 627	arch_release_hugepage(page);
 628	__free_pages(page, huge_page_order(h));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 629}
 630
 631struct hstate *size_to_hstate(unsigned long size)
 632{
 633	struct hstate *h;
 634
 635	for_each_hstate(h) {
 636		if (huge_page_size(h) == size)
 637			return h;
 638	}
 639	return NULL;
 640}
 641
 642static void free_huge_page(struct page *page)
 643{
 644	/*
 645	 * Can't pass hstate in here because it is called from the
 646	 * compound page destructor.
 647	 */
 648	struct hstate *h = page_hstate(page);
 649	int nid = page_to_nid(page);
 650	struct hugepage_subpool *spool =
 651		(struct hugepage_subpool *)page_private(page);
 652	bool restore_reserve;
 
 653
 654	set_page_private(page, 0);
 655	page->mapping = NULL;
 656	BUG_ON(page_count(page));
 657	BUG_ON(page_mapcount(page));
 658	restore_reserve = PagePrivate(page);
 659	ClearPagePrivate(page);
 660
 661	spin_lock(&hugetlb_lock);
 662	hugetlb_cgroup_uncharge_page(hstate_index(h),
 663				     pages_per_huge_page(h), page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 664	if (restore_reserve)
 665		h->resv_huge_pages++;
 666
 667	if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
 
 
 
 
 668		/* remove the page from active list */
 669		list_del(&page->lru);
 670		update_and_free_page(h, page);
 671		h->surplus_huge_pages--;
 672		h->surplus_huge_pages_node[nid]--;
 673	} else {
 674		arch_clear_hugepage_flags(page);
 675		enqueue_huge_page(h, page);
 
 676	}
 677	spin_unlock(&hugetlb_lock);
 678	hugepage_subpool_put_pages(spool, 1);
 679}
 680
 681static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
 
 
 
 682{
 683	INIT_LIST_HEAD(&page->lru);
 684	set_compound_page_dtor(page, free_huge_page);
 685	spin_lock(&hugetlb_lock);
 686	set_hugetlb_cgroup(page, NULL);
 687	h->nr_huge_pages++;
 688	h->nr_huge_pages_node[nid]++;
 689	spin_unlock(&hugetlb_lock);
 690	put_page(page); /* free it into the hugepage allocator */
 691}
 692
 693static void __init prep_compound_gigantic_page(struct page *page,
 694					       unsigned long order)
 695{
 696	int i;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 697	int nr_pages = 1 << order;
 698	struct page *p = page + 1;
 
 
 
 
 699
 700	/* we rely on prep_new_huge_page to set the destructor */
 701	set_compound_order(page, order);
 702	__SetPageHead(page);
 703	__ClearPageReserved(page);
 704	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
 705		__SetPageTail(p);
 706		/*
 707		 * For gigantic hugepages allocated through bootmem at
 708		 * boot, it's safer to be consistent with the not-gigantic
 709		 * hugepages and clear the PG_reserved bit from all tail pages
 710		 * too.  Otherwse drivers using get_user_pages() to access tail
 711		 * pages may get the reference counting wrong if they see
 712		 * PG_reserved set on a tail page (despite the head page not
 713		 * having PG_reserved set).  Enforcing this consistency between
 714		 * head and tail pages allows drivers to optimize away a check
 715		 * on the head page when they need know if put_page() is needed
 716		 * after get_user_pages().
 717		 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 718		__ClearPageReserved(p);
 719		set_page_count(p, 0);
 720		p->first_page = page;
 721	}
 
 722}
 723
 724/*
 725 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 726 * transparent huge pages.  See the PageTransHuge() documentation for more
 727 * details.
 728 */
 729int PageHuge(struct page *page)
 730{
 731	if (!PageCompound(page))
 732		return 0;
 733
 734	page = compound_head(page);
 735	return get_compound_page_dtor(page) == free_huge_page;
 
 
 736}
 737EXPORT_SYMBOL_GPL(PageHuge);
 738
 739/*
 740 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
 741 * normal or transparent huge pages.
 
 
 
 742 */
 743int PageHeadHuge(struct page *page_head)
 744{
 745	if (!PageHead(page_head))
 746		return 0;
 
 
 747
 748	return get_compound_page_dtor(page_head) == free_huge_page;
 
 
 
 749}
 750
 751pgoff_t __basepage_index(struct page *page)
 
 
 752{
 753	struct page *page_head = compound_head(page);
 754	pgoff_t index = page_index(page_head);
 755	unsigned long compound_idx;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 756
 757	if (!PageHuge(page_head))
 758		return page_index(page);
 
 
 
 
 
 
 
 
 
 759
 760	if (compound_order(page_head) >= MAX_ORDER)
 761		compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
 762	else
 763		compound_idx = page - page_head;
 
 
 
 
 
 
 
 
 
 
 
 764
 765	return (index << compound_order(page_head)) + compound_idx;
 
 
 
 
 
 
 766}
 767
 768static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
 
 
 769{
 770	struct page *page;
 
 771
 772	if (h->order >= MAX_ORDER)
 
 
 
 
 
 
 773		return NULL;
 774
 775	page = alloc_pages_exact_node(nid,
 776		htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
 777						__GFP_REPEAT|__GFP_NOWARN,
 778		huge_page_order(h));
 779	if (page) {
 780		if (arch_prepare_hugepage(page)) {
 781			__free_pages(page, huge_page_order(h));
 
 
 
 
 782			return NULL;
 783		}
 784		prep_new_huge_page(h, page, nid);
 785	}
 786
 787	return page;
 788}
 789
 790/*
 791 * common helper functions for hstate_next_node_to_{alloc|free}.
 792 * We may have allocated or freed a huge page based on a different
 793 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
 794 * be outside of *nodes_allowed.  Ensure that we use an allowed
 795 * node for alloc or free.
 796 */
 797static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
 798{
 799	nid = next_node(nid, *nodes_allowed);
 800	if (nid == MAX_NUMNODES)
 801		nid = first_node(*nodes_allowed);
 802	VM_BUG_ON(nid >= MAX_NUMNODES);
 803
 804	return nid;
 805}
 806
 807static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
 808{
 809	if (!node_isset(nid, *nodes_allowed))
 810		nid = next_node_allowed(nid, nodes_allowed);
 811	return nid;
 812}
 813
 814/*
 815 * returns the previously saved node ["this node"] from which to
 816 * allocate a persistent huge page for the pool and advance the
 817 * next node from which to allocate, handling wrap at end of node
 818 * mask.
 
 819 */
 820static int hstate_next_node_to_alloc(struct hstate *h,
 821					nodemask_t *nodes_allowed)
 822{
 823	int nid;
 824
 825	VM_BUG_ON(!nodes_allowed);
 826
 827	nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
 828	h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
 
 829
 830	return nid;
 
 831}
 832
 833/*
 834 * helper for free_pool_huge_page() - return the previously saved
 835 * node ["this node"] from which to free a huge page.  Advance the
 836 * next node id whether or not we find a free huge page to free so
 837 * that the next attempt to free addresses the next node.
 838 */
 839static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
 840{
 841	int nid;
 842
 843	VM_BUG_ON(!nodes_allowed);
 844
 845	nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
 846	h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
 847
 848	return nid;
 
 
 
 
 
 
 849}
 850
 851#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask)		\
 852	for (nr_nodes = nodes_weight(*mask);				\
 853		nr_nodes > 0 &&						\
 854		((node = hstate_next_node_to_alloc(hs, mask)) || 1);	\
 855		nr_nodes--)
 856
 857#define for_each_node_mask_to_free(hs, nr_nodes, node, mask)		\
 858	for (nr_nodes = nodes_weight(*mask);				\
 859		nr_nodes > 0 &&						\
 860		((node = hstate_next_node_to_free(hs, mask)) || 1);	\
 861		nr_nodes--)
 862
 863static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
 864{
 865	struct page *page;
 866	int nr_nodes, node;
 867	int ret = 0;
 868
 869	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
 870		page = alloc_fresh_huge_page_node(h, node);
 871		if (page) {
 872			ret = 1;
 873			break;
 874		}
 875	}
 876
 877	if (ret)
 878		count_vm_event(HTLB_BUDDY_PGALLOC);
 879	else
 880		count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
 
 881
 882	return ret;
 883}
 884
 885/*
 886 * Free huge page from pool from next node to free.
 887 * Attempt to keep persistent huge pages more or less
 888 * balanced over allowed nodes.
 
 889 * Called with hugetlb_lock locked.
 890 */
 891static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
 892							 bool acct_surplus)
 893{
 894	int nr_nodes, node;
 895	int ret = 0;
 896
 
 897	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
 898		/*
 899		 * If we're returning unused surplus pages, only examine
 900		 * nodes with surplus pages.
 901		 */
 902		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
 903		    !list_empty(&h->hugepage_freelists[node])) {
 904			struct page *page =
 905				list_entry(h->hugepage_freelists[node].next,
 906					  struct page, lru);
 907			list_del(&page->lru);
 908			h->free_huge_pages--;
 909			h->free_huge_pages_node[node]--;
 910			if (acct_surplus) {
 911				h->surplus_huge_pages--;
 912				h->surplus_huge_pages_node[node]--;
 913			}
 914			update_and_free_page(h, page);
 915			ret = 1;
 916			break;
 917		}
 918	}
 919
 920	return ret;
 921}
 922
 923/*
 924 * Dissolve a given free hugepage into free buddy pages. This function does
 925 * nothing for in-use (including surplus) hugepages.
 
 
 
 
 
 
 
 
 
 
 926 */
 927static void dissolve_free_huge_page(struct page *page)
 928{
 929	spin_lock(&hugetlb_lock);
 930	if (PageHuge(page) && !page_count(page)) {
 931		struct hstate *h = page_hstate(page);
 932		int nid = page_to_nid(page);
 933		list_del(&page->lru);
 934		h->free_huge_pages--;
 935		h->free_huge_pages_node[nid]--;
 936		update_and_free_page(h, page);
 
 
 
 
 937	}
 938	spin_unlock(&hugetlb_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 939}
 940
 941/*
 942 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 943 * make specified memory blocks removable from the system.
 944 * Note that start_pfn should aligned with (minimum) hugepage size.
 
 
 
 945 */
 946void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
 947{
 948	unsigned int order = 8 * sizeof(void *);
 949	unsigned long pfn;
 
 
 
 950	struct hstate *h;
 951
 952	/* Set scan step to minimum hugepage size */
 
 
 
 953	for_each_hstate(h)
 954		if (order > huge_page_order(h))
 955			order = huge_page_order(h);
 956	VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
 957	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
 958		dissolve_free_huge_page(pfn_to_page(pfn));
 
 
 
 
 
 959}
 960
 961static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
 
 
 
 
 962{
 963	struct page *page;
 964	unsigned int r_nid;
 965
 966	if (h->order >= MAX_ORDER)
 967		return NULL;
 968
 
 
 
 
 
 
 
 
 
 
 969	/*
 970	 * Assume we will successfully allocate the surplus page to
 971	 * prevent racing processes from causing the surplus to exceed
 972	 * overcommit
 973	 *
 974	 * This however introduces a different race, where a process B
 975	 * tries to grow the static hugepage pool while alloc_pages() is
 976	 * called by process A. B will only examine the per-node
 977	 * counters in determining if surplus huge pages can be
 978	 * converted to normal huge pages in adjust_pool_surplus(). A
 979	 * won't be able to increment the per-node counter, until the
 980	 * lock is dropped by B, but B doesn't drop hugetlb_lock until
 981	 * no more huge pages can be converted from surplus to normal
 982	 * state (and doesn't try to convert again). Thus, we have a
 983	 * case where a surplus huge page exists, the pool is grown, and
 984	 * the surplus huge page still exists after, even though it
 985	 * should just have been converted to a normal huge page. This
 986	 * does not leak memory, though, as the hugepage will be freed
 987	 * once it is out of use. It also does not allow the counters to
 988	 * go out of whack in adjust_pool_surplus() as we don't modify
 989	 * the node values until we've gotten the hugepage and only the
 990	 * per-node value is checked there.
 991	 */
 992	spin_lock(&hugetlb_lock);
 993	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
 994		spin_unlock(&hugetlb_lock);
 
 
 995		return NULL;
 996	} else {
 997		h->nr_huge_pages++;
 998		h->surplus_huge_pages++;
 999	}
1000	spin_unlock(&hugetlb_lock);
1001
1002	if (nid == NUMA_NO_NODE)
1003		page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP|
1004				   __GFP_REPEAT|__GFP_NOWARN,
1005				   huge_page_order(h));
1006	else
1007		page = alloc_pages_exact_node(nid,
1008			htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1009			__GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
1010
1011	if (page && arch_prepare_hugepage(page)) {
1012		__free_pages(page, huge_page_order(h));
1013		page = NULL;
1014	}
1015
1016	spin_lock(&hugetlb_lock);
1017	if (page) {
1018		INIT_LIST_HEAD(&page->lru);
1019		r_nid = page_to_nid(page);
1020		set_compound_page_dtor(page, free_huge_page);
1021		set_hugetlb_cgroup(page, NULL);
1022		/*
1023		 * We incremented the global counters already
1024		 */
1025		h->nr_huge_pages_node[r_nid]++;
1026		h->surplus_huge_pages_node[r_nid]++;
1027		__count_vm_event(HTLB_BUDDY_PGALLOC);
1028	} else {
1029		h->nr_huge_pages--;
1030		h->surplus_huge_pages--;
1031		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1032	}
1033	spin_unlock(&hugetlb_lock);
1034
1035	return page;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1036}
1037
1038/*
1039 * This allocation function is useful in the context where vma is irrelevant.
1040 * E.g. soft-offlining uses this function because it only cares physical
1041 * address of error page.
1042 */
1043struct page *alloc_huge_page_node(struct hstate *h, int nid)
 
 
1044{
1045	struct page *page = NULL;
 
 
 
 
1046
1047	spin_lock(&hugetlb_lock);
1048	if (h->free_huge_pages - h->resv_huge_pages > 0)
1049		page = dequeue_huge_page_node(h, nid);
1050	spin_unlock(&hugetlb_lock);
1051
1052	if (!page)
1053		page = alloc_buddy_huge_page(h, nid);
1054
1055	return page;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1056}
1057
1058/*
1059 * Increase the hugetlb pool such that it can accommodate a reservation
1060 * of size 'delta'.
1061 */
1062static int gather_surplus_pages(struct hstate *h, int delta)
 
1063{
1064	struct list_head surplus_list;
1065	struct page *page, *tmp;
1066	int ret, i;
1067	int needed, allocated;
 
1068	bool alloc_ok = true;
1069
 
1070	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1071	if (needed <= 0) {
1072		h->resv_huge_pages += delta;
1073		return 0;
1074	}
1075
1076	allocated = 0;
1077	INIT_LIST_HEAD(&surplus_list);
1078
1079	ret = -ENOMEM;
1080retry:
1081	spin_unlock(&hugetlb_lock);
1082	for (i = 0; i < needed; i++) {
1083		page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1084		if (!page) {
 
1085			alloc_ok = false;
1086			break;
1087		}
1088		list_add(&page->lru, &surplus_list);
 
1089	}
1090	allocated += i;
1091
1092	/*
1093	 * After retaking hugetlb_lock, we need to recalculate 'needed'
1094	 * because either resv_huge_pages or free_huge_pages may have changed.
1095	 */
1096	spin_lock(&hugetlb_lock);
1097	needed = (h->resv_huge_pages + delta) -
1098			(h->free_huge_pages + allocated);
1099	if (needed > 0) {
1100		if (alloc_ok)
1101			goto retry;
1102		/*
1103		 * We were not able to allocate enough pages to
1104		 * satisfy the entire reservation so we free what
1105		 * we've allocated so far.
1106		 */
1107		goto free;
1108	}
1109	/*
1110	 * The surplus_list now contains _at_least_ the number of extra pages
1111	 * needed to accommodate the reservation.  Add the appropriate number
1112	 * of pages to the hugetlb pool and free the extras back to the buddy
1113	 * allocator.  Commit the entire reservation here to prevent another
1114	 * process from stealing the pages as they are added to the pool but
1115	 * before they are reserved.
1116	 */
1117	needed += allocated;
1118	h->resv_huge_pages += delta;
1119	ret = 0;
1120
1121	/* Free the needed pages to the hugetlb pool */
1122	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1123		if ((--needed) < 0)
1124			break;
1125		/*
1126		 * This page is now managed by the hugetlb allocator and has
1127		 * no users -- drop the buddy allocator's reference.
1128		 */
1129		put_page_testzero(page);
1130		VM_BUG_ON_PAGE(page_count(page), page);
1131		enqueue_huge_page(h, page);
1132	}
1133free:
1134	spin_unlock(&hugetlb_lock);
1135
1136	/* Free unnecessary surplus pages to the buddy allocator */
1137	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
1138		put_page(page);
1139	spin_lock(&hugetlb_lock);
 
 
 
1140
1141	return ret;
1142}
1143
1144/*
1145 * When releasing a hugetlb pool reservation, any surplus pages that were
1146 * allocated to satisfy the reservation must be explicitly freed if they were
1147 * never used.
1148 * Called with hugetlb_lock held.
 
 
1149 */
1150static void return_unused_surplus_pages(struct hstate *h,
1151					unsigned long unused_resv_pages)
1152{
1153	unsigned long nr_pages;
 
1154
 
1155	/* Uncommit the reservation */
1156	h->resv_huge_pages -= unused_resv_pages;
1157
1158	/* Cannot return gigantic pages currently */
1159	if (h->order >= MAX_ORDER)
1160		return;
1161
 
 
 
 
1162	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1163
1164	/*
1165	 * We want to release as many surplus pages as possible, spread
1166	 * evenly across all nodes with memory. Iterate across these nodes
1167	 * until we can no longer free unreserved surplus pages. This occurs
1168	 * when the nodes with surplus pages have no free pages.
1169	 * free_pool_huge_page() will balance the the freed pages across the
1170	 * on-line nodes with memory and will handle the hstate accounting.
1171	 */
1172	while (nr_pages--) {
1173		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1174			break;
1175		cond_resched_lock(&hugetlb_lock);
 
 
 
 
1176	}
 
 
 
 
 
1177}
1178
 
1179/*
1180 * Determine if the huge page at addr within the vma has an associated
1181 * reservation.  Where it does not we will need to logically increase
1182 * reservation and actually increase subpool usage before an allocation
1183 * can occur.  Where any new reservation would be required the
1184 * reservation change is prepared, but not committed.  Once the page
1185 * has been allocated from the subpool and instantiated the change should
1186 * be committed via vma_commit_reservation.  No action is required on
1187 * failure.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1188 */
1189static long vma_needs_reservation(struct hstate *h,
1190			struct vm_area_struct *vma, unsigned long addr)
 
 
 
 
 
 
 
 
1191{
1192	struct resv_map *resv;
1193	pgoff_t idx;
1194	long chg;
 
1195
1196	resv = vma_resv_map(vma);
1197	if (!resv)
1198		return 1;
1199
1200	idx = vma_hugecache_offset(h, vma, addr);
1201	chg = region_chg(resv, idx, idx + 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1202
1203	if (vma->vm_flags & VM_MAYSHARE)
1204		return chg;
1205	else
1206		return chg < 0 ? chg : 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1207}
1208static void vma_commit_reservation(struct hstate *h,
 
1209			struct vm_area_struct *vma, unsigned long addr)
1210{
1211	struct resv_map *resv;
1212	pgoff_t idx;
1213
1214	resv = vma_resv_map(vma);
1215	if (!resv)
1216		return;
 
 
1217
1218	idx = vma_hugecache_offset(h, vma, addr);
1219	region_add(resv, idx, idx + 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1220}
1221
1222static struct page *alloc_huge_page(struct vm_area_struct *vma,
1223				    unsigned long addr, int avoid_reserve)
1224{
1225	struct hugepage_subpool *spool = subpool_vma(vma);
1226	struct hstate *h = hstate_vma(vma);
1227	struct page *page;
1228	long chg;
1229	int ret, idx;
1230	struct hugetlb_cgroup *h_cg;
 
 
 
 
 
 
 
 
 
 
 
1231
1232	idx = hstate_index(h);
1233	/*
1234	 * Processes that did not create the mapping will have no
1235	 * reserves and will not have accounted against subpool
1236	 * limit. Check that the subpool limit can be made before
1237	 * satisfying the allocation MAP_NORESERVE mappings may also
1238	 * need pages and subpool limit allocated allocated if no reserve
1239	 * mapping overlaps.
1240	 */
1241	chg = vma_needs_reservation(h, vma, addr);
1242	if (chg < 0)
 
 
 
1243		return ERR_PTR(-ENOMEM);
1244	if (chg || avoid_reserve)
1245		if (hugepage_subpool_get_pages(spool, 1))
1246			return ERR_PTR(-ENOSPC);
1247
1248	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1249	if (ret) {
1250		if (chg || avoid_reserve)
1251			hugepage_subpool_put_pages(spool, 1);
1252		return ERR_PTR(-ENOSPC);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1253	}
1254	spin_lock(&hugetlb_lock);
1255	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
1256	if (!page) {
1257		spin_unlock(&hugetlb_lock);
1258		page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
1259		if (!page) {
1260			hugetlb_cgroup_uncharge_cgroup(idx,
1261						       pages_per_huge_page(h),
1262						       h_cg);
1263			if (chg || avoid_reserve)
1264				hugepage_subpool_put_pages(spool, 1);
1265			return ERR_PTR(-ENOSPC);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1266		}
1267		spin_lock(&hugetlb_lock);
1268		list_move(&page->lru, &h->hugepage_activelist);
1269		/* Fall through */
1270	}
1271	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
1272	spin_unlock(&hugetlb_lock);
1273
1274	set_page_private(page, (unsigned long)spool);
 
 
 
 
 
 
 
1275
1276	vma_commit_reservation(h, vma, addr);
1277	return page;
1278}
1279
1280/*
1281 * alloc_huge_page()'s wrapper which simply returns the page if allocation
1282 * succeeds, otherwise NULL. This function is called from new_vma_page(),
1283 * where no ERR_VALUE is expected to be returned.
1284 */
1285struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
1286				unsigned long addr, int avoid_reserve)
1287{
1288	struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
1289	if (IS_ERR(page))
1290		page = NULL;
1291	return page;
1292}
1293
1294int __weak alloc_bootmem_huge_page(struct hstate *h)
1295{
1296	struct huge_bootmem_page *m;
1297	int nr_nodes, node;
 
 
 
 
 
 
 
 
1298
1299	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1300		void *addr;
 
 
 
 
 
 
 
1301
1302		addr = memblock_virt_alloc_try_nid_nopanic(
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1303				huge_page_size(h), huge_page_size(h),
1304				0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1305		if (addr) {
1306			/*
1307			 * Use the beginning of the huge page to store the
1308			 * huge_bootmem_page struct (until gather_bootmem
1309			 * puts them into the mem_map).
1310			 */
1311			m = addr;
1312			goto found;
1313		}
1314	}
1315	return 0;
1316
1317found:
1318	BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
 
 
 
 
 
 
 
 
 
1319	/* Put them into a private list first because mem_map is not up yet */
1320	list_add(&m->list, &huge_boot_pages);
 
1321	m->hstate = h;
1322	return 1;
1323}
1324
1325static void __init prep_compound_huge_page(struct page *page, int order)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1326{
1327	if (unlikely(order > (MAX_ORDER - 1)))
1328		prep_compound_gigantic_page(page, order);
1329	else
1330		prep_compound_page(page, order);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1331}
1332
1333/* Put bootmem huge pages into the standard lists after mem_map is up */
1334static void __init gather_bootmem_prealloc(void)
 
 
 
1335{
 
1336	struct huge_bootmem_page *m;
 
1337
1338	list_for_each_entry(m, &huge_boot_pages, list) {
1339		struct hstate *h = m->hstate;
1340		struct page *page;
1341
1342#ifdef CONFIG_HIGHMEM
1343		page = pfn_to_page(m->phys >> PAGE_SHIFT);
1344		memblock_free_late(__pa(m),
1345				   sizeof(struct huge_bootmem_page));
1346#else
1347		page = virt_to_page(m);
1348#endif
1349		WARN_ON(page_count(page) != 1);
1350		prep_compound_huge_page(page, h->order);
1351		WARN_ON(PageReserved(page));
1352		prep_new_huge_page(h, page, page_to_nid(page));
1353		/*
1354		 * If we had gigantic hugepages allocated at boot time, we need
1355		 * to restore the 'stolen' pages to totalram_pages in order to
1356		 * fix confusing memory reports from free(1) and another
1357		 * side-effects, like CommitLimit going negative.
 
 
 
 
 
1358		 */
1359		if (h->order > (MAX_ORDER - 1))
1360			adjust_managed_page_count(page, 1 << h->order);
1361	}
 
 
1362}
1363
1364static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1365{
1366	unsigned long i;
 
1367
1368	for (i = 0; i < h->max_huge_pages; ++i) {
1369		if (h->order >= MAX_ORDER) {
1370			if (!alloc_bootmem_huge_page(h))
1371				break;
1372		} else if (!alloc_fresh_huge_page(h,
1373					 &node_states[N_MEMORY]))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1374			break;
 
 
 
1375	}
1376	h->max_huge_pages = i;
 
1377}
1378
1379static void __init hugetlb_init_hstates(void)
1380{
1381	struct hstate *h;
1382
1383	for_each_hstate(h) {
1384		/* oversize hugepages were init'ed in early boot */
1385		if (h->order < MAX_ORDER)
1386			hugetlb_hstate_alloc_pages(h);
1387	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1388}
1389
1390static char * __init memfmt(char *buf, unsigned long n)
 
 
 
 
 
 
 
 
 
 
 
1391{
1392	if (n >= (1UL << 30))
1393		sprintf(buf, "%lu GB", n >> 30);
1394	else if (n >= (1UL << 20))
1395		sprintf(buf, "%lu MB", n >> 20);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1396	else
1397		sprintf(buf, "%lu KB", n >> 10);
1398	return buf;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1399}
1400
1401static void __init report_hugepages(void)
1402{
1403	struct hstate *h;
1404
1405	for_each_hstate(h) {
1406		char buf[32];
1407		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
1408			memfmt(buf, huge_page_size(h)),
1409			h->free_huge_pages);
 
 
 
1410	}
1411}
1412
1413#ifdef CONFIG_HIGHMEM
1414static void try_to_free_low(struct hstate *h, unsigned long count,
1415						nodemask_t *nodes_allowed)
1416{
1417	int i;
 
1418
1419	if (h->order >= MAX_ORDER)
 
1420		return;
1421
 
 
 
1422	for_each_node_mask(i, *nodes_allowed) {
1423		struct page *page, *next;
1424		struct list_head *freel = &h->hugepage_freelists[i];
1425		list_for_each_entry_safe(page, next, freel, lru) {
1426			if (count >= h->nr_huge_pages)
1427				return;
1428			if (PageHighMem(page))
1429				continue;
1430			list_del(&page->lru);
1431			update_and_free_page(h, page);
1432			h->free_huge_pages--;
1433			h->free_huge_pages_node[page_to_nid(page)]--;
1434		}
1435	}
 
 
 
 
 
1436}
1437#else
1438static inline void try_to_free_low(struct hstate *h, unsigned long count,
1439						nodemask_t *nodes_allowed)
1440{
1441}
1442#endif
1443
1444/*
1445 * Increment or decrement surplus_huge_pages.  Keep node-specific counters
1446 * balanced by operating on them in a round-robin fashion.
1447 * Returns 1 if an adjustment was made.
1448 */
1449static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
1450				int delta)
1451{
1452	int nr_nodes, node;
1453
 
1454	VM_BUG_ON(delta != -1 && delta != 1);
1455
1456	if (delta < 0) {
1457		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1458			if (h->surplus_huge_pages_node[node])
1459				goto found;
1460		}
1461	} else {
1462		for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1463			if (h->surplus_huge_pages_node[node] <
1464					h->nr_huge_pages_node[node])
1465				goto found;
1466		}
1467	}
1468	return 0;
1469
1470found:
1471	h->surplus_huge_pages += delta;
1472	h->surplus_huge_pages_node[node] += delta;
1473	return 1;
1474}
1475
1476#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1477static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
1478						nodemask_t *nodes_allowed)
1479{
1480	unsigned long min_count, ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1481
1482	if (h->order >= MAX_ORDER)
1483		return h->max_huge_pages;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1484
1485	/*
1486	 * Increase the pool size
1487	 * First take pages out of surplus state.  Then make up the
1488	 * remaining difference by allocating fresh huge pages.
1489	 *
1490	 * We might race with alloc_buddy_huge_page() here and be unable
1491	 * to convert a surplus huge page to a normal huge page. That is
1492	 * not critical, though, it just means the overall size of the
1493	 * pool might be one hugepage larger than it needs to be, but
1494	 * within all the constraints specified by the sysctls.
1495	 */
1496	spin_lock(&hugetlb_lock);
1497	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1498		if (!adjust_pool_surplus(h, nodes_allowed, -1))
1499			break;
1500	}
1501
1502	while (count > persistent_huge_pages(h)) {
 
1503		/*
1504		 * If this allocation races such that we no longer need the
1505		 * page, free_huge_page will handle it by freeing the page
1506		 * and reducing the surplus.
1507		 */
1508		spin_unlock(&hugetlb_lock);
1509		ret = alloc_fresh_huge_page(h, nodes_allowed);
1510		spin_lock(&hugetlb_lock);
1511		if (!ret)
 
 
 
 
 
 
 
1512			goto out;
 
 
 
 
1513
1514		/* Bail for signals. Probably ctrl-c from user */
1515		if (signal_pending(current))
 
 
1516			goto out;
 
 
 
 
 
 
 
 
 
 
1517	}
1518
1519	/*
1520	 * Decrease the pool size
1521	 * First return free pages to the buddy allocator (being careful
1522	 * to keep enough around to satisfy reservations).  Then place
1523	 * pages into surplus state as needed so the pool will shrink
1524	 * to the desired size as pages become free.
1525	 *
1526	 * By placing pages into the surplus state independent of the
1527	 * overcommit value, we are allowing the surplus pool size to
1528	 * exceed overcommit. There are few sane options here. Since
1529	 * alloc_buddy_huge_page() is checking the global counter,
1530	 * though, we'll note that we're not allowed to exceed surplus
1531	 * and won't grow the pool anywhere else. Not until one of the
1532	 * sysctls are changed, or the surplus pages go out of use.
1533	 */
1534	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1535	min_count = max(count, min_count);
1536	try_to_free_low(h, min_count, nodes_allowed);
 
 
 
 
1537	while (min_count < persistent_huge_pages(h)) {
1538		if (!free_pool_huge_page(h, nodes_allowed, 0))
 
1539			break;
1540		cond_resched_lock(&hugetlb_lock);
 
1541	}
 
 
 
 
 
 
1542	while (count < persistent_huge_pages(h)) {
1543		if (!adjust_pool_surplus(h, nodes_allowed, 1))
1544			break;
1545	}
1546out:
1547	ret = persistent_huge_pages(h);
1548	spin_unlock(&hugetlb_lock);
1549	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1550}
1551
1552#define HSTATE_ATTR_RO(_name) \
1553	static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
1554
 
 
 
1555#define HSTATE_ATTR(_name) \
1556	static struct kobj_attribute _name##_attr = \
1557		__ATTR(_name, 0644, _name##_show, _name##_store)
1558
1559static struct kobject *hugepages_kobj;
1560static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
1561
1562static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
1563
1564static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1565{
1566	int i;
1567
1568	for (i = 0; i < HUGE_MAX_HSTATE; i++)
1569		if (hstate_kobjs[i] == kobj) {
1570			if (nidp)
1571				*nidp = NUMA_NO_NODE;
1572			return &hstates[i];
1573		}
1574
1575	return kobj_to_node_hstate(kobj, nidp);
1576}
1577
1578static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1579					struct kobj_attribute *attr, char *buf)
1580{
1581	struct hstate *h;
1582	unsigned long nr_huge_pages;
1583	int nid;
1584
1585	h = kobj_to_hstate(kobj, &nid);
1586	if (nid == NUMA_NO_NODE)
1587		nr_huge_pages = h->nr_huge_pages;
1588	else
1589		nr_huge_pages = h->nr_huge_pages_node[nid];
1590
1591	return sprintf(buf, "%lu\n", nr_huge_pages);
1592}
1593
1594static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
1595			struct kobject *kobj, struct kobj_attribute *attr,
1596			const char *buf, size_t len)
1597{
1598	int err;
1599	int nid;
1600	unsigned long count;
1601	struct hstate *h;
1602	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1603
1604	err = kstrtoul(buf, 10, &count);
1605	if (err)
1606		goto out;
1607
1608	h = kobj_to_hstate(kobj, &nid);
1609	if (h->order >= MAX_ORDER) {
1610		err = -EINVAL;
1611		goto out;
1612	}
1613
1614	if (nid == NUMA_NO_NODE) {
1615		/*
1616		 * global hstate attribute
1617		 */
1618		if (!(obey_mempolicy &&
1619				init_nodemask_of_mempolicy(nodes_allowed))) {
1620			NODEMASK_FREE(nodes_allowed);
1621			nodes_allowed = &node_states[N_MEMORY];
1622		}
1623	} else if (nodes_allowed) {
1624		/*
1625		 * per node hstate attribute: adjust count to global,
1626		 * but restrict alloc/free to the specified node.
1627		 */
1628		count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
1629		init_nodemask_of_node(nodes_allowed, nid);
1630	} else
1631		nodes_allowed = &node_states[N_MEMORY];
1632
1633	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1634
1635	if (nodes_allowed != &node_states[N_MEMORY])
1636		NODEMASK_FREE(nodes_allowed);
1637
1638	return len;
1639out:
1640	NODEMASK_FREE(nodes_allowed);
1641	return err;
 
 
 
 
 
 
 
 
 
 
 
1642}
1643
1644static ssize_t nr_hugepages_show(struct kobject *kobj,
1645				       struct kobj_attribute *attr, char *buf)
1646{
1647	return nr_hugepages_show_common(kobj, attr, buf);
1648}
1649
1650static ssize_t nr_hugepages_store(struct kobject *kobj,
1651	       struct kobj_attribute *attr, const char *buf, size_t len)
1652{
1653	return nr_hugepages_store_common(false, kobj, attr, buf, len);
1654}
1655HSTATE_ATTR(nr_hugepages);
1656
1657#ifdef CONFIG_NUMA
1658
1659/*
1660 * hstate attribute for optionally mempolicy-based constraint on persistent
1661 * huge page alloc/free.
1662 */
1663static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
1664				       struct kobj_attribute *attr, char *buf)
 
1665{
1666	return nr_hugepages_show_common(kobj, attr, buf);
1667}
1668
1669static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
1670	       struct kobj_attribute *attr, const char *buf, size_t len)
1671{
1672	return nr_hugepages_store_common(true, kobj, attr, buf, len);
1673}
1674HSTATE_ATTR(nr_hugepages_mempolicy);
1675#endif
1676
1677
1678static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
1679					struct kobj_attribute *attr, char *buf)
1680{
1681	struct hstate *h = kobj_to_hstate(kobj, NULL);
1682	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
1683}
1684
1685static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
1686		struct kobj_attribute *attr, const char *buf, size_t count)
1687{
1688	int err;
1689	unsigned long input;
1690	struct hstate *h = kobj_to_hstate(kobj, NULL);
1691
1692	if (h->order >= MAX_ORDER)
1693		return -EINVAL;
1694
1695	err = kstrtoul(buf, 10, &input);
1696	if (err)
1697		return err;
1698
1699	spin_lock(&hugetlb_lock);
1700	h->nr_overcommit_huge_pages = input;
1701	spin_unlock(&hugetlb_lock);
1702
1703	return count;
1704}
1705HSTATE_ATTR(nr_overcommit_hugepages);
1706
1707static ssize_t free_hugepages_show(struct kobject *kobj,
1708					struct kobj_attribute *attr, char *buf)
1709{
1710	struct hstate *h;
1711	unsigned long free_huge_pages;
1712	int nid;
1713
1714	h = kobj_to_hstate(kobj, &nid);
1715	if (nid == NUMA_NO_NODE)
1716		free_huge_pages = h->free_huge_pages;
1717	else
1718		free_huge_pages = h->free_huge_pages_node[nid];
1719
1720	return sprintf(buf, "%lu\n", free_huge_pages);
1721}
1722HSTATE_ATTR_RO(free_hugepages);
1723
1724static ssize_t resv_hugepages_show(struct kobject *kobj,
1725					struct kobj_attribute *attr, char *buf)
1726{
1727	struct hstate *h = kobj_to_hstate(kobj, NULL);
1728	return sprintf(buf, "%lu\n", h->resv_huge_pages);
1729}
1730HSTATE_ATTR_RO(resv_hugepages);
1731
1732static ssize_t surplus_hugepages_show(struct kobject *kobj,
1733					struct kobj_attribute *attr, char *buf)
1734{
1735	struct hstate *h;
1736	unsigned long surplus_huge_pages;
1737	int nid;
1738
1739	h = kobj_to_hstate(kobj, &nid);
1740	if (nid == NUMA_NO_NODE)
1741		surplus_huge_pages = h->surplus_huge_pages;
1742	else
1743		surplus_huge_pages = h->surplus_huge_pages_node[nid];
1744
1745	return sprintf(buf, "%lu\n", surplus_huge_pages);
1746}
1747HSTATE_ATTR_RO(surplus_hugepages);
1748
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1749static struct attribute *hstate_attrs[] = {
1750	&nr_hugepages_attr.attr,
1751	&nr_overcommit_hugepages_attr.attr,
1752	&free_hugepages_attr.attr,
1753	&resv_hugepages_attr.attr,
1754	&surplus_hugepages_attr.attr,
1755#ifdef CONFIG_NUMA
1756	&nr_hugepages_mempolicy_attr.attr,
1757#endif
1758	NULL,
1759};
1760
1761static struct attribute_group hstate_attr_group = {
1762	.attrs = hstate_attrs,
1763};
1764
 
 
 
 
 
 
 
 
 
 
1765static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
1766				    struct kobject **hstate_kobjs,
1767				    struct attribute_group *hstate_attr_group)
1768{
1769	int retval;
1770	int hi = hstate_index(h);
1771
1772	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
1773	if (!hstate_kobjs[hi])
1774		return -ENOMEM;
1775
1776	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1777	if (retval)
1778		kobject_put(hstate_kobjs[hi]);
 
 
 
1779
1780	return retval;
1781}
1782
1783static void __init hugetlb_sysfs_init(void)
1784{
1785	struct hstate *h;
1786	int err;
1787
1788	hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
1789	if (!hugepages_kobj)
1790		return;
1791
1792	for_each_hstate(h) {
1793		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
1794					 hstate_kobjs, &hstate_attr_group);
1795		if (err)
1796			pr_err("Hugetlb: Unable to add hstate %s", h->name);
1797	}
 
 
1798}
1799
1800#ifdef CONFIG_NUMA
 
1801
1802/*
1803 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1804 * with node devices in node_devices[] using a parallel array.  The array
1805 * index of a node device or _hstate == node id.
1806 * This is here to avoid any static dependency of the node device driver, in
1807 * the base kernel, on the hugetlb module.
1808 */
1809struct node_hstate {
1810	struct kobject		*hugepages_kobj;
1811	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
1812};
1813struct node_hstate node_hstates[MAX_NUMNODES];
1814
1815/*
1816 * A subset of global hstate attributes for node devices
1817 */
1818static struct attribute *per_node_hstate_attrs[] = {
1819	&nr_hugepages_attr.attr,
1820	&free_hugepages_attr.attr,
1821	&surplus_hugepages_attr.attr,
1822	NULL,
1823};
1824
1825static struct attribute_group per_node_hstate_attr_group = {
1826	.attrs = per_node_hstate_attrs,
1827};
1828
1829/*
1830 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1831 * Returns node id via non-NULL nidp.
1832 */
1833static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1834{
1835	int nid;
1836
1837	for (nid = 0; nid < nr_node_ids; nid++) {
1838		struct node_hstate *nhs = &node_hstates[nid];
1839		int i;
1840		for (i = 0; i < HUGE_MAX_HSTATE; i++)
1841			if (nhs->hstate_kobjs[i] == kobj) {
1842				if (nidp)
1843					*nidp = nid;
1844				return &hstates[i];
1845			}
1846	}
1847
1848	BUG();
1849	return NULL;
1850}
1851
1852/*
1853 * Unregister hstate attributes from a single node device.
1854 * No-op if no hstate attributes attached.
1855 */
1856static void hugetlb_unregister_node(struct node *node)
1857{
1858	struct hstate *h;
1859	struct node_hstate *nhs = &node_hstates[node->dev.id];
1860
1861	if (!nhs->hugepages_kobj)
1862		return;		/* no hstate attributes */
1863
1864	for_each_hstate(h) {
1865		int idx = hstate_index(h);
1866		if (nhs->hstate_kobjs[idx]) {
1867			kobject_put(nhs->hstate_kobjs[idx]);
1868			nhs->hstate_kobjs[idx] = NULL;
1869		}
 
 
 
 
 
1870	}
1871
1872	kobject_put(nhs->hugepages_kobj);
1873	nhs->hugepages_kobj = NULL;
1874}
1875
1876/*
1877 * hugetlb module exit:  unregister hstate attributes from node devices
1878 * that have them.
1879 */
1880static void hugetlb_unregister_all_nodes(void)
1881{
1882	int nid;
1883
1884	/*
1885	 * disable node device registrations.
1886	 */
1887	register_hugetlbfs_with_node(NULL, NULL);
1888
1889	/*
1890	 * remove hstate attributes from any nodes that have them.
1891	 */
1892	for (nid = 0; nid < nr_node_ids; nid++)
1893		hugetlb_unregister_node(node_devices[nid]);
1894}
1895
1896/*
1897 * Register hstate attributes for a single node device.
1898 * No-op if attributes already registered.
1899 */
1900static void hugetlb_register_node(struct node *node)
1901{
1902	struct hstate *h;
1903	struct node_hstate *nhs = &node_hstates[node->dev.id];
1904	int err;
1905
 
 
 
1906	if (nhs->hugepages_kobj)
1907		return;		/* already allocated */
1908
1909	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1910							&node->dev.kobj);
1911	if (!nhs->hugepages_kobj)
1912		return;
1913
1914	for_each_hstate(h) {
1915		err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
1916						nhs->hstate_kobjs,
1917						&per_node_hstate_attr_group);
1918		if (err) {
1919			pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
1920				h->name, node->dev.id);
1921			hugetlb_unregister_node(node);
1922			break;
1923		}
1924	}
1925}
1926
1927/*
1928 * hugetlb init time:  register hstate attributes for all registered node
1929 * devices of nodes that have memory.  All on-line nodes should have
1930 * registered their associated device by this time.
1931 */
1932static void hugetlb_register_all_nodes(void)
1933{
1934	int nid;
1935
1936	for_each_node_state(nid, N_MEMORY) {
1937		struct node *node = node_devices[nid];
1938		if (node->dev.id == nid)
1939			hugetlb_register_node(node);
1940	}
1941
1942	/*
1943	 * Let the node device driver know we're here so it can
1944	 * [un]register hstate attributes on node hotplug.
1945	 */
1946	register_hugetlbfs_with_node(hugetlb_register_node,
1947				     hugetlb_unregister_node);
1948}
1949#else	/* !CONFIG_NUMA */
1950
1951static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
1952{
1953	BUG();
1954	if (nidp)
1955		*nidp = -1;
1956	return NULL;
1957}
1958
1959static void hugetlb_unregister_all_nodes(void) { }
1960
1961static void hugetlb_register_all_nodes(void) { }
1962
1963#endif
1964
1965static void __exit hugetlb_exit(void)
 
 
 
 
 
 
 
 
1966{
1967	struct hstate *h;
 
1968
1969	hugetlb_unregister_all_nodes();
 
 
1970
1971	for_each_hstate(h) {
1972		kobject_put(hstate_kobjs[hstate_index(h)]);
 
 
 
1973	}
1974
1975	kobject_put(hugepages_kobj);
1976	kfree(htlb_fault_mutex_table);
 
 
1977}
1978module_exit(hugetlb_exit);
 
 
 
 
 
1979
1980static int __init hugetlb_init(void)
1981{
1982	int i;
1983
1984	if (!hugepages_supported())
 
 
 
 
 
1985		return 0;
 
1986
1987	if (!size_to_hstate(default_hstate_size)) {
1988		default_hstate_size = HPAGE_SIZE;
1989		if (!size_to_hstate(default_hstate_size))
1990			hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1991	}
1992	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1993	if (default_hstate_max_huge_pages)
1994		default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1995
 
1996	hugetlb_init_hstates();
1997	gather_bootmem_prealloc();
1998	report_hugepages();
1999
2000	hugetlb_sysfs_init();
2001	hugetlb_register_all_nodes();
2002	hugetlb_cgroup_file_init();
 
2003
2004#ifdef CONFIG_SMP
2005	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
2006#else
2007	num_fault_mutexes = 1;
2008#endif
2009	htlb_fault_mutex_table =
2010		kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2011	BUG_ON(!htlb_fault_mutex_table);
 
2012
2013	for (i = 0; i < num_fault_mutexes; i++)
2014		mutex_init(&htlb_fault_mutex_table[i]);
2015	return 0;
2016}
2017module_init(hugetlb_init);
 
 
 
 
 
 
2018
2019/* Should be called on processing a hugepagesz=... option */
2020void __init hugetlb_add_hstate(unsigned order)
2021{
2022	struct hstate *h;
2023	unsigned long i;
2024
2025	if (size_to_hstate(PAGE_SIZE << order)) {
2026		pr_warning("hugepagesz= specified twice, ignoring\n");
2027		return;
2028	}
2029	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2030	BUG_ON(order == 0);
2031	h = &hstates[hugetlb_max_hstate++];
 
2032	h->order = order;
2033	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2034	h->nr_huge_pages = 0;
2035	h->free_huge_pages = 0;
2036	for (i = 0; i < MAX_NUMNODES; ++i)
2037		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2038	INIT_LIST_HEAD(&h->hugepage_activelist);
2039	h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
2040	h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2041	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
2042					huge_page_size(h)/1024);
2043
2044	parsed_hstate = h;
2045}
2046
2047static int __init hugetlb_nrpages_setup(char *s)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2048{
2049	unsigned long *mhp;
2050	static unsigned long *last_mhp;
 
 
 
 
 
 
 
 
 
 
2051
2052	/*
2053	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2054	 * so this hugepages= parameter goes to the "default hstate".
 
 
2055	 */
2056	if (!hugetlb_max_hstate)
2057		mhp = &default_hstate_max_huge_pages;
2058	else
2059		mhp = &parsed_hstate->max_huge_pages;
2060
2061	if (mhp == last_mhp) {
2062		pr_warning("hugepages= specified twice without "
2063			   "interleaving hugepagesz=, ignoring\n");
2064		return 1;
2065	}
2066
2067	if (sscanf(s, "%lu", mhp) <= 0)
2068		*mhp = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2069
2070	/*
2071	 * Global state is always initialized later in hugetlb_init.
2072	 * But we need to allocate >= MAX_ORDER hstates here early to still
2073	 * use the bootmem allocator.
2074	 */
2075	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2076		hugetlb_hstate_alloc_pages(parsed_hstate);
2077
2078	last_mhp = mhp;
2079
2080	return 1;
 
 
 
 
 
2081}
2082__setup("hugepages=", hugetlb_nrpages_setup);
2083
2084static int __init hugetlb_default_setup(char *s)
 
 
 
 
 
 
 
2085{
2086	default_hstate_size = memparse(s, &s);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2087	return 1;
2088}
2089__setup("default_hugepagesz=", hugetlb_default_setup);
2090
2091static unsigned int cpuset_mems_nr(unsigned int *array)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2092{
2093	int node;
2094	unsigned int nr = 0;
2095
2096	for_each_node_mask(node, cpuset_current_mems_allowed)
2097		nr += array[node];
 
 
 
 
 
 
2098
2099	return nr;
2100}
2101
2102#ifdef CONFIG_SYSCTL
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2103static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
2104			 struct ctl_table *table, int write,
2105			 void __user *buffer, size_t *length, loff_t *ppos)
2106{
2107	struct hstate *h = &default_hstate;
2108	unsigned long tmp;
2109	int ret;
2110
2111	if (!hugepages_supported())
2112		return -ENOTSUPP;
2113
2114	tmp = h->max_huge_pages;
2115
2116	if (write && h->order >= MAX_ORDER)
2117		return -EINVAL;
2118
2119	table->data = &tmp;
2120	table->maxlen = sizeof(unsigned long);
2121	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2122	if (ret)
2123		goto out;
2124
2125	if (write) {
2126		NODEMASK_ALLOC(nodemask_t, nodes_allowed,
2127						GFP_KERNEL | __GFP_NORETRY);
2128		if (!(obey_mempolicy &&
2129			       init_nodemask_of_mempolicy(nodes_allowed))) {
2130			NODEMASK_FREE(nodes_allowed);
2131			nodes_allowed = &node_states[N_MEMORY];
2132		}
2133		h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
2134
2135		if (nodes_allowed != &node_states[N_MEMORY])
2136			NODEMASK_FREE(nodes_allowed);
2137	}
2138out:
2139	return ret;
2140}
2141
2142int hugetlb_sysctl_handler(struct ctl_table *table, int write,
2143			  void __user *buffer, size_t *length, loff_t *ppos)
2144{
2145
2146	return hugetlb_sysctl_handler_common(false, table, write,
2147							buffer, length, ppos);
2148}
2149
2150#ifdef CONFIG_NUMA
2151int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
2152			  void __user *buffer, size_t *length, loff_t *ppos)
2153{
2154	return hugetlb_sysctl_handler_common(true, table, write,
2155							buffer, length, ppos);
2156}
2157#endif /* CONFIG_NUMA */
2158
2159int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2160			void __user *buffer,
2161			size_t *length, loff_t *ppos)
2162{
2163	struct hstate *h = &default_hstate;
2164	unsigned long tmp;
2165	int ret;
2166
2167	if (!hugepages_supported())
2168		return -ENOTSUPP;
2169
2170	tmp = h->nr_overcommit_huge_pages;
2171
2172	if (write && h->order >= MAX_ORDER)
2173		return -EINVAL;
2174
2175	table->data = &tmp;
2176	table->maxlen = sizeof(unsigned long);
2177	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
2178	if (ret)
2179		goto out;
2180
2181	if (write) {
2182		spin_lock(&hugetlb_lock);
2183		h->nr_overcommit_huge_pages = tmp;
2184		spin_unlock(&hugetlb_lock);
2185	}
2186out:
2187	return ret;
2188}
2189
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2190#endif /* CONFIG_SYSCTL */
2191
2192void hugetlb_report_meminfo(struct seq_file *m)
2193{
2194	struct hstate *h = &default_hstate;
 
 
2195	if (!hugepages_supported())
2196		return;
2197	seq_printf(m,
2198			"HugePages_Total:   %5lu\n"
2199			"HugePages_Free:    %5lu\n"
2200			"HugePages_Rsvd:    %5lu\n"
2201			"HugePages_Surp:    %5lu\n"
2202			"Hugepagesize:   %8lu kB\n",
2203			h->nr_huge_pages,
2204			h->free_huge_pages,
2205			h->resv_huge_pages,
2206			h->surplus_huge_pages,
2207			1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
 
 
 
 
 
 
 
 
 
 
2208}
2209
2210int hugetlb_report_node_meminfo(int nid, char *buf)
2211{
2212	struct hstate *h = &default_hstate;
 
2213	if (!hugepages_supported())
2214		return 0;
2215	return sprintf(buf,
2216		"Node %d HugePages_Total: %5u\n"
2217		"Node %d HugePages_Free:  %5u\n"
2218		"Node %d HugePages_Surp:  %5u\n",
2219		nid, h->nr_huge_pages_node[nid],
2220		nid, h->free_huge_pages_node[nid],
2221		nid, h->surplus_huge_pages_node[nid]);
 
2222}
2223
2224void hugetlb_show_meminfo(void)
2225{
2226	struct hstate *h;
2227	int nid;
2228
2229	if (!hugepages_supported())
2230		return;
2231
2232	for_each_node_state(nid, N_MEMORY)
2233		for_each_hstate(h)
2234			pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
2235				nid,
2236				h->nr_huge_pages_node[nid],
2237				h->free_huge_pages_node[nid],
2238				h->surplus_huge_pages_node[nid],
2239				1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
 
 
 
 
 
2240}
2241
2242/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
2243unsigned long hugetlb_total_pages(void)
2244{
2245	struct hstate *h;
2246	unsigned long nr_total_pages = 0;
2247
2248	for_each_hstate(h)
2249		nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
2250	return nr_total_pages;
2251}
2252
2253static int hugetlb_acct_memory(struct hstate *h, long delta)
2254{
2255	int ret = -ENOMEM;
2256
2257	spin_lock(&hugetlb_lock);
 
 
 
2258	/*
2259	 * When cpuset is configured, it breaks the strict hugetlb page
2260	 * reservation as the accounting is done on a global variable. Such
2261	 * reservation is completely rubbish in the presence of cpuset because
2262	 * the reservation is not checked against page availability for the
2263	 * current cpuset. Application can still potentially OOM'ed by kernel
2264	 * with lack of free htlb page in cpuset that the task is in.
2265	 * Attempt to enforce strict accounting with cpuset is almost
2266	 * impossible (or too ugly) because cpuset is too fluid that
2267	 * task or memory node can be dynamically moved between cpusets.
2268	 *
2269	 * The change of semantics for shared hugetlb mapping with cpuset is
2270	 * undesirable. However, in order to preserve some of the semantics,
2271	 * we fall back to check against current free page availability as
2272	 * a best attempt and hopefully to minimize the impact of changing
2273	 * semantics that cpuset has.
 
 
 
 
 
 
2274	 */
2275	if (delta > 0) {
2276		if (gather_surplus_pages(h, delta) < 0)
2277			goto out;
2278
2279		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
2280			return_unused_surplus_pages(h, delta);
2281			goto out;
2282		}
2283	}
2284
2285	ret = 0;
2286	if (delta < 0)
2287		return_unused_surplus_pages(h, (unsigned long) -delta);
2288
2289out:
2290	spin_unlock(&hugetlb_lock);
2291	return ret;
2292}
2293
2294static void hugetlb_vm_op_open(struct vm_area_struct *vma)
2295{
2296	struct resv_map *resv = vma_resv_map(vma);
2297
2298	/*
 
2299	 * This new VMA should share its siblings reservation map if present.
2300	 * The VMA will only ever have a valid reservation map pointer where
2301	 * it is being copied for another still existing VMA.  As that VMA
2302	 * has a reference to the reservation map it cannot disappear until
2303	 * after this open call completes.  It is therefore safe to take a
2304	 * new reference here without additional locking.
2305	 */
2306	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
 
2307		kref_get(&resv->refs);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2308}
2309
2310static void hugetlb_vm_op_close(struct vm_area_struct *vma)
2311{
2312	struct hstate *h = hstate_vma(vma);
2313	struct resv_map *resv = vma_resv_map(vma);
2314	struct hugepage_subpool *spool = subpool_vma(vma);
2315	unsigned long reserve, start, end;
 
 
 
2316
 
2317	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2318		return;
2319
2320	start = vma_hugecache_offset(h, vma, vma->vm_start);
2321	end = vma_hugecache_offset(h, vma, vma->vm_end);
2322
2323	reserve = (end - start) - region_count(resv, start, end);
 
 
 
 
 
 
 
 
 
2324
2325	kref_put(&resv->refs, resv_map_release);
 
2326
2327	if (reserve) {
2328		hugetlb_acct_memory(h, -reserve);
2329		hugepage_subpool_put_pages(spool, reserve);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2330	}
 
 
 
 
 
 
 
2331}
2332
2333/*
2334 * We cannot handle pagefaults against hugetlb pages at all.  They cause
2335 * handle_mm_fault() to try to instantiate regular-sized pages in the
2336 * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
2337 * this far.
2338 */
2339static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
2340{
2341	BUG();
2342	return 0;
2343}
2344
 
 
 
 
 
 
 
2345const struct vm_operations_struct hugetlb_vm_ops = {
2346	.fault = hugetlb_vm_op_fault,
2347	.open = hugetlb_vm_op_open,
2348	.close = hugetlb_vm_op_close,
 
 
2349};
2350
2351static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
2352				int writable)
2353{
2354	pte_t entry;
 
2355
2356	if (writable) {
2357		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
2358					 vma->vm_page_prot)));
2359	} else {
2360		entry = huge_pte_wrprotect(mk_huge_pte(page,
2361					   vma->vm_page_prot));
2362	}
2363	entry = pte_mkyoung(entry);
2364	entry = pte_mkhuge(entry);
2365	entry = arch_make_huge_pte(entry, vma, page, writable);
2366
2367	return entry;
2368}
2369
2370static void set_huge_ptep_writable(struct vm_area_struct *vma,
2371				   unsigned long address, pte_t *ptep)
2372{
2373	pte_t entry;
2374
2375	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
2376	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2377		update_mmu_cache(vma, address, ptep);
2378}
2379
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2380
2381int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
2382			    struct vm_area_struct *vma)
 
2383{
2384	pte_t *src_pte, *dst_pte, entry;
2385	struct page *ptepage;
2386	unsigned long addr;
2387	int cow;
2388	struct hstate *h = hstate_vma(vma);
2389	unsigned long sz = huge_page_size(h);
2390	unsigned long mmun_start;	/* For mmu_notifiers */
2391	unsigned long mmun_end;		/* For mmu_notifiers */
 
2392	int ret = 0;
2393
2394	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
2395
2396	mmun_start = vma->vm_start;
2397	mmun_end = vma->vm_end;
2398	if (cow)
2399		mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
 
 
 
 
 
 
 
 
 
 
2400
2401	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
 
2402		spinlock_t *src_ptl, *dst_ptl;
2403		src_pte = huge_pte_offset(src, addr);
2404		if (!src_pte)
 
2405			continue;
2406		dst_pte = huge_pte_alloc(dst, addr, sz);
 
2407		if (!dst_pte) {
2408			ret = -ENOMEM;
2409			break;
2410		}
2411
2412		/* If the pagetables are shared don't copy or take references */
2413		if (dst_pte == src_pte)
 
 
 
 
 
 
 
 
2414			continue;
 
2415
2416		dst_ptl = huge_pte_lock(h, dst, dst_pte);
2417		src_ptl = huge_pte_lockptr(h, src, src_pte);
2418		spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
2419		if (!huge_pte_none(huge_ptep_get(src_pte))) {
2420			if (cow)
2421				huge_ptep_set_wrprotect(src, addr, src_pte);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2422			entry = huge_ptep_get(src_pte);
2423			ptepage = pte_page(entry);
2424			get_page(ptepage);
2425			page_dup_rmap(ptepage);
2426			set_huge_pte_at(dst, addr, dst_pte, entry);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2427		}
2428		spin_unlock(src_ptl);
2429		spin_unlock(dst_ptl);
2430	}
2431
2432	if (cow)
2433		mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
 
 
 
 
2434
2435	return ret;
2436}
2437
2438static int is_hugetlb_entry_migration(pte_t pte)
 
 
2439{
2440	swp_entry_t swp;
 
 
 
2441
2442	if (huge_pte_none(pte) || pte_present(pte))
2443		return 0;
2444	swp = pte_to_swp_entry(pte);
2445	if (non_swap_entry(swp) && is_migration_entry(swp))
2446		return 1;
2447	else
2448		return 0;
 
 
 
 
 
 
 
 
 
2449}
2450
2451static int is_hugetlb_entry_hwpoisoned(pte_t pte)
 
 
 
2452{
2453	swp_entry_t swp;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2454
2455	if (huge_pte_none(pte) || pte_present(pte))
2456		return 0;
2457	swp = pte_to_swp_entry(pte);
2458	if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2459		return 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2460	else
2461		return 0;
 
 
 
 
 
2462}
2463
2464void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
2465			    unsigned long start, unsigned long end,
2466			    struct page *ref_page)
2467{
2468	int force_flush = 0;
2469	struct mm_struct *mm = vma->vm_mm;
2470	unsigned long address;
2471	pte_t *ptep;
2472	pte_t pte;
2473	spinlock_t *ptl;
2474	struct page *page;
2475	struct hstate *h = hstate_vma(vma);
2476	unsigned long sz = huge_page_size(h);
2477	const unsigned long mmun_start = start;	/* For mmu_notifiers */
2478	const unsigned long mmun_end   = end;	/* For mmu_notifiers */
 
2479
2480	WARN_ON(!is_vm_hugetlb_page(vma));
2481	BUG_ON(start & ~huge_page_mask(h));
2482	BUG_ON(end & ~huge_page_mask(h));
2483
 
 
 
 
 
2484	tlb_start_vma(tlb, vma);
2485	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2486again:
2487	for (address = start; address < end; address += sz) {
2488		ptep = huge_pte_offset(mm, address);
2489		if (!ptep)
 
 
2490			continue;
 
2491
2492		ptl = huge_pte_lock(h, mm, ptep);
2493		if (huge_pmd_unshare(mm, &address, ptep))
2494			goto unlock;
 
 
 
 
 
2495
2496		pte = huge_ptep_get(ptep);
2497		if (huge_pte_none(pte))
2498			goto unlock;
 
 
2499
2500		/*
2501		 * HWPoisoned hugepage is already unmapped and dropped reference
 
2502		 */
2503		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
2504			huge_pte_clear(mm, address, ptep);
2505			goto unlock;
 
 
 
 
 
 
 
 
 
 
 
 
 
2506		}
2507
2508		page = pte_page(pte);
2509		/*
2510		 * If a reference page is supplied, it is because a specific
2511		 * page is being unmapped, not a range. Ensure the page we
2512		 * are about to unmap is the actual page of interest.
2513		 */
2514		if (ref_page) {
2515			if (page != ref_page)
2516				goto unlock;
2517
 
2518			/*
2519			 * Mark the VMA as having unmapped its page so that
2520			 * future faults in this VMA will fail rather than
2521			 * looking like data was lost
2522			 */
2523			set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
2524		}
2525
2526		pte = huge_ptep_get_and_clear(mm, address, ptep);
2527		tlb_remove_tlb_entry(tlb, ptep, address);
2528		if (huge_pte_dirty(pte))
2529			set_page_dirty(page);
 
 
 
 
 
 
 
 
2530
2531		page_remove_rmap(page);
2532		force_flush = !__tlb_remove_page(tlb, page);
2533		if (force_flush) {
2534			spin_unlock(ptl);
2535			break;
2536		}
2537		/* Bail out after unmapping reference page if supplied */
2538		if (ref_page) {
2539			spin_unlock(ptl);
2540			break;
 
2541		}
2542unlock:
2543		spin_unlock(ptl);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2544	}
2545	/*
2546	 * mmu_gather ran out of room to batch pages, we break out of
2547	 * the PTE lock to avoid doing the potential expensive TLB invalidate
2548	 * and page-free while holding it.
2549	 */
2550	if (force_flush) {
2551		force_flush = 0;
2552		tlb_flush_mmu(tlb);
2553		if (address < end && !ref_page)
2554			goto again;
2555	}
2556	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2557	tlb_end_vma(tlb, vma);
2558}
2559
2560void __unmap_hugepage_range_final(struct mmu_gather *tlb,
2561			  struct vm_area_struct *vma, unsigned long start,
2562			  unsigned long end, struct page *ref_page)
2563{
2564	__unmap_hugepage_range(tlb, vma, start, end, ref_page);
2565
2566	/*
2567	 * Clear this flag so that x86's huge_pmd_share page_table_shareable
2568	 * test will fail on a vma being torn down, and not grab a page table
2569	 * on its way out.  We're lucky that the flag has such an appropriate
2570	 * name, and can in fact be safely cleared here. We could clear it
2571	 * before the __unmap_hugepage_range above, but all that's necessary
2572	 * is to clear it before releasing the i_mmap_mutex. This works
2573	 * because in the context this is called, the VMA is about to be
2574	 * destroyed and the i_mmap_mutex is held.
2575	 */
2576	vma->vm_flags &= ~VM_MAYSHARE;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2577}
2578
2579void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2580			  unsigned long end, struct page *ref_page)
 
2581{
2582	struct mm_struct *mm;
2583	struct mmu_gather tlb;
2584
2585	mm = vma->vm_mm;
 
 
 
 
 
 
2586
2587	tlb_gather_mmu(&tlb, mm, start, end);
2588	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
2589	tlb_finish_mmu(&tlb, start, end);
2590}
2591
2592/*
2593 * This is called when the original mapper is failing to COW a MAP_PRIVATE
2594 * mappping it owns the reserve page for. The intention is to unmap the page
2595 * from other VMAs and let the children be SIGKILLed if they are faulting the
2596 * same region.
2597 */
2598static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
2599				struct page *page, unsigned long address)
2600{
2601	struct hstate *h = hstate_vma(vma);
2602	struct vm_area_struct *iter_vma;
2603	struct address_space *mapping;
2604	pgoff_t pgoff;
2605
2606	/*
2607	 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
2608	 * from page cache lookup which is in HPAGE_SIZE units.
2609	 */
2610	address = address & huge_page_mask(h);
2611	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
2612			vma->vm_pgoff;
2613	mapping = file_inode(vma->vm_file)->i_mapping;
2614
2615	/*
2616	 * Take the mapping lock for the duration of the table walk. As
2617	 * this mapping should be shared between all the VMAs,
2618	 * __unmap_hugepage_range() is called as the lock is already held
2619	 */
2620	mutex_lock(&mapping->i_mmap_mutex);
2621	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2622		/* Do not unmap the current VMA */
2623		if (iter_vma == vma)
2624			continue;
2625
2626		/*
 
 
 
 
 
 
 
 
2627		 * Unmap the page from other VMAs without their own reserves.
2628		 * They get marked to be SIGKILLed if they fault in these
2629		 * areas. This is because a future no-page fault on this VMA
2630		 * could insert a zeroed page instead of the data existing
2631		 * from the time of fork. This would look like data corruption
2632		 */
2633		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2634			unmap_hugepage_range(iter_vma, address,
2635					     address + huge_page_size(h), page);
2636	}
2637	mutex_unlock(&mapping->i_mmap_mutex);
2638
2639	return 1;
2640}
2641
2642/*
2643 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2644 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
2645 * cannot race with other handlers or page migration.
2646 * Keep the pte_same checks anyway to make transition from the mutex easier.
2647 */
2648static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2649			unsigned long address, pte_t *ptep, pte_t pte,
2650			struct page *pagecache_page, spinlock_t *ptl)
 
2651{
 
 
2652	struct hstate *h = hstate_vma(vma);
2653	struct page *old_page, *new_page;
 
2654	int outside_reserve = 0;
2655	unsigned long mmun_start;	/* For mmu_notifiers */
2656	unsigned long mmun_end;		/* For mmu_notifiers */
 
2657
2658	old_page = pte_page(pte);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2659
2660retry_avoidcopy:
2661	/* If no-one else is actually using this page, avoid the copy
2662	 * and just make the page writable */
2663	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
2664		page_move_anon_rmap(old_page, vma, address);
2665		set_huge_ptep_writable(vma, address, ptep);
 
 
 
 
 
 
 
 
2666		return 0;
2667	}
 
 
2668
2669	/*
2670	 * If the process that created a MAP_PRIVATE mapping is about to
2671	 * perform a COW due to a shared page count, attempt to satisfy
2672	 * the allocation without using the existing reserves. The pagecache
2673	 * page is used to determine if the reserve at this address was
2674	 * consumed or not. If reserves were used, a partial faulted mapping
2675	 * at the time of fork() could consume its reserves on COW instead
2676	 * of the full address range.
2677	 */
2678	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
2679			old_page != pagecache_page)
2680		outside_reserve = 1;
2681
2682	page_cache_get(old_page);
2683
2684	/* Drop page table lock as buddy allocator may be called */
 
 
 
2685	spin_unlock(ptl);
2686	new_page = alloc_huge_page(vma, address, outside_reserve);
2687
2688	if (IS_ERR(new_page)) {
2689		long err = PTR_ERR(new_page);
2690		page_cache_release(old_page);
2691
 
2692		/*
2693		 * If a process owning a MAP_PRIVATE mapping fails to COW,
2694		 * it is due to references held by a child and an insufficient
2695		 * huge page pool. To guarantee the original mappers
2696		 * reliability, unmap the page from child processes. The child
2697		 * may get SIGKILLed if it later faults.
2698		 */
2699		if (outside_reserve) {
2700			BUG_ON(huge_pte_none(pte));
2701			if (unmap_ref_private(mm, vma, old_page, address)) {
2702				BUG_ON(huge_pte_none(pte));
2703				spin_lock(ptl);
2704				ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2705				if (likely(ptep &&
2706					   pte_same(huge_ptep_get(ptep), pte)))
2707					goto retry_avoidcopy;
2708				/*
2709				 * race occurs while re-acquiring page table
2710				 * lock, and our job is done.
2711				 */
2712				return 0;
2713			}
2714			WARN_ON_ONCE(1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2715		}
2716
2717		/* Caller expects lock to be held */
2718		spin_lock(ptl);
2719		if (err == -ENOMEM)
2720			return VM_FAULT_OOM;
2721		else
2722			return VM_FAULT_SIGBUS;
2723	}
2724
2725	/*
2726	 * When the original hugepage is shared one, it does not have
2727	 * anon_vma prepared.
2728	 */
2729	if (unlikely(anon_vma_prepare(vma))) {
2730		page_cache_release(new_page);
2731		page_cache_release(old_page);
2732		/* Caller expects lock to be held */
2733		spin_lock(ptl);
2734		return VM_FAULT_OOM;
2735	}
 
 
 
 
 
 
2736
2737	copy_user_huge_page(new_page, old_page, address, vma,
2738			    pages_per_huge_page(h));
2739	__SetPageUptodate(new_page);
2740
2741	mmun_start = address & huge_page_mask(h);
2742	mmun_end = mmun_start + huge_page_size(h);
2743	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2744	/*
2745	 * Retake the page table lock to check for racing updates
2746	 * before the page tables are altered
2747	 */
2748	spin_lock(ptl);
2749	ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2750	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
2751		ClearPagePrivate(new_page);
2752
2753		/* Break COW */
2754		huge_ptep_clear_flush(vma, address, ptep);
2755		set_huge_pte_at(mm, address, ptep,
2756				make_huge_pte(vma, new_page, 1));
2757		page_remove_rmap(old_page);
2758		hugepage_add_new_anon_rmap(new_page, vma, address);
 
 
2759		/* Make the old page be freed below */
2760		new_page = old_page;
2761	}
2762	spin_unlock(ptl);
2763	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2764	page_cache_release(new_page);
2765	page_cache_release(old_page);
 
 
 
 
 
 
 
 
2766
2767	/* Caller expects lock to be held */
2768	spin_lock(ptl);
2769	return 0;
 
2770}
2771
2772/* Return the pagecache page at a given address within a VMA */
2773static struct page *hugetlbfs_pagecache_page(struct hstate *h,
 
 
2774			struct vm_area_struct *vma, unsigned long address)
2775{
2776	struct address_space *mapping;
2777	pgoff_t idx;
 
2778
2779	mapping = vma->vm_file->f_mapping;
2780	idx = vma_hugecache_offset(h, vma, address);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2781
2782	return find_lock_page(mapping, idx);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2783}
2784
2785/*
2786 * Return whether there is a pagecache page to back given address within VMA.
2787 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
2788 */
2789static bool hugetlbfs_pagecache_present(struct hstate *h,
2790			struct vm_area_struct *vma, unsigned long address)
2791{
2792	struct address_space *mapping;
2793	pgoff_t idx;
2794	struct page *page;
2795
2796	mapping = vma->vm_file->f_mapping;
2797	idx = vma_hugecache_offset(h, vma, address);
 
2798
2799	page = find_get_page(mapping, idx);
2800	if (page)
2801		put_page(page);
2802	return page != NULL;
2803}
2804
2805static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2806			   struct address_space *mapping, pgoff_t idx,
2807			   unsigned long address, pte_t *ptep, unsigned int flags)
 
 
 
2808{
2809	struct hstate *h = hstate_vma(vma);
2810	int ret = VM_FAULT_SIGBUS;
2811	int anon_rmap = 0;
2812	unsigned long size;
2813	struct page *page;
2814	pte_t new_pte;
2815	spinlock_t *ptl;
 
 
 
2816
2817	/*
2818	 * Currently, we are forced to kill the process in the event the
2819	 * original mapper has unmapped pages from the child due to a failed
2820	 * COW. Warn that such a situation has occurred as it may not be obvious
 
2821	 */
2822	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
2823		pr_warning("PID %d killed due to inadequate hugepage pool\n",
2824			   current->pid);
2825		return ret;
2826	}
2827
2828	/*
2829	 * Use page lock to guard against racing truncation
2830	 * before we get page_table_lock.
2831	 */
2832retry:
2833	page = find_lock_page(mapping, idx);
2834	if (!page) {
2835		size = i_size_read(mapping->host) >> huge_page_shift(h);
2836		if (idx >= size)
2837			goto out;
2838		page = alloc_huge_page(vma, address, 0);
2839		if (IS_ERR(page)) {
2840			ret = PTR_ERR(page);
2841			if (ret == -ENOMEM)
2842				ret = VM_FAULT_OOM;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2843			else
2844				ret = VM_FAULT_SIGBUS;
2845			goto out;
2846		}
2847		clear_huge_page(page, address, pages_per_huge_page(h));
2848		__SetPageUptodate(page);
 
2849
2850		if (vma->vm_flags & VM_MAYSHARE) {
2851			int err;
2852			struct inode *inode = mapping->host;
2853
2854			err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
2855			if (err) {
2856				put_page(page);
2857				if (err == -EEXIST)
2858					goto retry;
 
 
 
 
 
 
 
2859				goto out;
2860			}
2861			ClearPagePrivate(page);
2862
2863			spin_lock(&inode->i_lock);
2864			inode->i_blocks += blocks_per_huge_page(h);
2865			spin_unlock(&inode->i_lock);
2866		} else {
2867			lock_page(page);
2868			if (unlikely(anon_vma_prepare(vma))) {
2869				ret = VM_FAULT_OOM;
2870				goto backout_unlocked;
2871			}
2872			anon_rmap = 1;
2873		}
2874	} else {
2875		/*
2876		 * If memory error occurs between mmap() and fault, some process
2877		 * don't have hwpoisoned swap entry for errored virtual address.
2878		 * So we need to block hugepage fault by PG_hwpoison bit check.
2879		 */
2880		if (unlikely(PageHWPoison(page))) {
2881			ret = VM_FAULT_HWPOISON |
2882				VM_FAULT_SET_HINDEX(hstate_index(h));
2883			goto backout_unlocked;
2884		}
 
 
 
 
 
 
 
 
 
 
 
 
 
2885	}
2886
2887	/*
2888	 * If we are going to COW a private mapping later, we examine the
2889	 * pending reservations for this page now. This will ensure that
2890	 * any allocations necessary to record that reservation occur outside
2891	 * the spinlock.
2892	 */
2893	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2894		if (vma_needs_reservation(h, vma, address) < 0) {
2895			ret = VM_FAULT_OOM;
2896			goto backout_unlocked;
2897		}
 
 
 
2898
2899	ptl = huge_pte_lockptr(h, mm, ptep);
2900	spin_lock(ptl);
2901	size = i_size_read(mapping->host) >> huge_page_shift(h);
2902	if (idx >= size)
2903		goto backout;
2904
2905	ret = 0;
2906	if (!huge_pte_none(huge_ptep_get(ptep)))
 
2907		goto backout;
2908
2909	if (anon_rmap) {
2910		ClearPagePrivate(page);
2911		hugepage_add_new_anon_rmap(page, vma, address);
2912	} else
2913		page_dup_rmap(page);
2914	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
2915				&& (vma->vm_flags & VM_SHARED)));
2916	set_huge_pte_at(mm, address, ptep, new_pte);
 
 
 
 
 
 
2917
 
2918	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2919		/* Optimization, do the COW without a second fault */
2920		ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
2921	}
2922
2923	spin_unlock(ptl);
2924	unlock_page(page);
 
 
 
 
 
 
 
 
 
2925out:
 
 
2926	return ret;
2927
2928backout:
2929	spin_unlock(ptl);
2930backout_unlocked:
2931	unlock_page(page);
2932	put_page(page);
 
 
 
2933	goto out;
2934}
2935
2936#ifdef CONFIG_SMP
2937static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2938			    struct vm_area_struct *vma,
2939			    struct address_space *mapping,
2940			    pgoff_t idx, unsigned long address)
2941{
2942	unsigned long key[2];
2943	u32 hash;
2944
2945	if (vma->vm_flags & VM_SHARED) {
2946		key[0] = (unsigned long) mapping;
2947		key[1] = idx;
2948	} else {
2949		key[0] = (unsigned long) mm;
2950		key[1] = address >> huge_page_shift(h);
2951	}
2952
2953	hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
2954
2955	return hash & (num_fault_mutexes - 1);
2956}
2957#else
2958/*
2959 * For uniprocesor systems we always use a single mutex, so just
2960 * return 0 and avoid the hashing overhead.
2961 */
2962static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
2963			    struct vm_area_struct *vma,
2964			    struct address_space *mapping,
2965			    pgoff_t idx, unsigned long address)
2966{
2967	return 0;
2968}
2969#endif
2970
2971int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2972			unsigned long address, unsigned int flags)
2973{
2974	pte_t *ptep, entry;
2975	spinlock_t *ptl;
2976	int ret;
2977	u32 hash;
2978	pgoff_t idx;
2979	struct page *page = NULL;
2980	struct page *pagecache_page = NULL;
2981	struct hstate *h = hstate_vma(vma);
2982	struct address_space *mapping;
 
 
 
 
 
 
 
 
 
2983
2984	address &= huge_page_mask(h);
2985
2986	ptep = huge_pte_offset(mm, address);
2987	if (ptep) {
2988		entry = huge_ptep_get(ptep);
2989		if (unlikely(is_hugetlb_entry_migration(entry))) {
2990			migration_entry_wait_huge(vma, mm, ptep);
2991			return 0;
2992		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2993			return VM_FAULT_HWPOISON_LARGE |
2994				VM_FAULT_SET_HINDEX(hstate_index(h));
2995	}
2996
2997	ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2998	if (!ptep)
2999		return VM_FAULT_OOM;
3000
3001	mapping = vma->vm_file->f_mapping;
3002	idx = vma_hugecache_offset(h, vma, address);
3003
3004	/*
3005	 * Serialize hugepage allocation and instantiation, so that we don't
3006	 * get spurious allocation failures if two CPUs race to instantiate
3007	 * the same page in the page cache.
3008	 */
3009	hash = fault_mutex_hash(h, mm, vma, mapping, idx, address);
3010	mutex_lock(&htlb_fault_mutex_table[hash]);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3011
3012	entry = huge_ptep_get(ptep);
3013	if (huge_pte_none(entry)) {
3014		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3015		goto out_mutex;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3016	}
3017
3018	ret = 0;
3019
3020	/*
3021	 * If we are going to COW the mapping later, we examine the pending
3022	 * reservations for this page now. This will ensure that any
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3023	 * allocations necessary to record that reservation occur outside the
3024	 * spinlock. For private mappings, we also lookup the pagecache
3025	 * page now as it is used to determine if a reservation has been
3026	 * consumed.
3027	 */
3028	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3029		if (vma_needs_reservation(h, vma, address) < 0) {
 
3030			ret = VM_FAULT_OOM;
3031			goto out_mutex;
3032		}
 
 
3033
3034		if (!(vma->vm_flags & VM_MAYSHARE))
3035			pagecache_page = hugetlbfs_pagecache_page(h,
3036								vma, address);
 
3037	}
3038
3039	/*
3040	 * hugetlb_cow() requires page locks of pte_page(entry) and
3041	 * pagecache_page, so here we need take the former one
3042	 * when page != pagecache_page or !pagecache_page.
3043	 * Note that locking order is always pagecache_page -> page,
3044	 * so no worry about deadlock.
3045	 */
3046	page = pte_page(entry);
3047	get_page(page);
3048	if (page != pagecache_page)
3049		lock_page(page);
3050
3051	ptl = huge_pte_lockptr(h, mm, ptep);
3052	spin_lock(ptl);
3053	/* Check for a racing update before calling hugetlb_cow */
3054	if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
3055		goto out_ptl;
3056
 
 
 
 
 
 
 
 
 
 
 
 
 
3057
3058	if (flags & FAULT_FLAG_WRITE) {
3059		if (!huge_pte_write(entry)) {
3060			ret = hugetlb_cow(mm, vma, address, ptep, entry,
3061					pagecache_page, ptl);
 
 
 
 
 
 
 
 
 
 
 
3062			goto out_ptl;
3063		}
3064		entry = huge_pte_mkdirty(entry);
 
 
 
 
 
 
 
 
 
 
3065	}
3066	entry = pte_mkyoung(entry);
3067	if (huge_ptep_set_access_flags(vma, address, ptep, entry,
3068						flags & FAULT_FLAG_WRITE))
3069		update_mmu_cache(vma, address, ptep);
3070
 
 
 
3071out_ptl:
3072	spin_unlock(ptl);
3073
3074	if (pagecache_page) {
3075		unlock_page(pagecache_page);
3076		put_page(pagecache_page);
3077	}
3078	if (page != pagecache_page)
3079		unlock_page(page);
3080	put_page(page);
3081
3082out_mutex:
3083	mutex_unlock(&htlb_fault_mutex_table[hash]);
 
 
 
 
 
 
 
 
 
 
3084	return ret;
3085}
3086
3087long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
3088			 struct page **pages, struct vm_area_struct **vmas,
3089			 unsigned long *position, unsigned long *nr_pages,
3090			 long i, unsigned int flags)
3091{
3092	unsigned long pfn_offset;
3093	unsigned long vaddr = *position;
3094	unsigned long remainder = *nr_pages;
3095	struct hstate *h = hstate_vma(vma);
 
 
 
3096
3097	while (vaddr < vma->vm_end && remainder) {
3098		pte_t *pte;
3099		spinlock_t *ptl = NULL;
3100		int absent;
3101		struct page *page;
3102
3103		/*
3104		 * Some archs (sparc64, sh*) have multiple pte_ts to
3105		 * each hugepage.  We have to make sure we get the
3106		 * first, for the page indexing below to work.
3107		 *
3108		 * Note that page table lock is not held when pte is null.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3109		 */
3110		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3111		if (pte)
3112			ptl = huge_pte_lock(h, mm, pte);
3113		absent = !pte || huge_pte_none(huge_ptep_get(pte));
3114
3115		/*
3116		 * When coredumping, it suits get_dump_page if we just return
3117		 * an error where there's an empty slot with no huge pagecache
3118		 * to back it.  This way, we avoid allocating a hugepage, and
3119		 * the sparse dumpfile avoids allocating disk blocks, but its
3120		 * huge holes still show up with zeroes where they need to be.
3121		 */
3122		if (absent && (flags & FOLL_DUMP) &&
3123		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3124			if (pte)
3125				spin_unlock(ptl);
3126			remainder = 0;
3127			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3128		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3129
3130		/*
3131		 * We need call hugetlb_fault for both hugepages under migration
3132		 * (in which case hugetlb_fault waits for the migration,) and
3133		 * hwpoisoned hugepages (in which case we need to prevent the
3134		 * caller from accessing to them.) In order to do this, we use
3135		 * here is_swap_pte instead of is_hugetlb_entry_migration and
3136		 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
3137		 * both cases, and because we can't follow correct pages
3138		 * directly from any kind of swap entries.
3139		 */
3140		if (absent || is_swap_pte(huge_ptep_get(pte)) ||
3141		    ((flags & FOLL_WRITE) &&
3142		      !huge_pte_write(huge_ptep_get(pte)))) {
3143			int ret;
 
3144
3145			if (pte)
3146				spin_unlock(ptl);
3147			ret = hugetlb_fault(mm, vma, vaddr,
3148				(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3149			if (!(ret & VM_FAULT_ERROR))
3150				continue;
3151
3152			remainder = 0;
3153			break;
3154		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3155
3156		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3157		page = pte_page(huge_ptep_get(pte));
3158same_page:
3159		if (pages) {
3160			pages[i] = mem_map_offset(page, pfn_offset);
3161			get_page_foll(pages[i]);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3162		}
3163
3164		if (vmas)
3165			vmas[i] = vma;
3166
3167		vaddr += PAGE_SIZE;
3168		++pfn_offset;
3169		--remainder;
3170		++i;
3171		if (vaddr < vma->vm_end && remainder &&
3172				pfn_offset < pages_per_huge_page(h)) {
3173			/*
3174			 * We use pfn_offset to avoid touching the pageframes
3175			 * of this compound page.
3176			 */
3177			goto same_page;
 
 
 
3178		}
3179		spin_unlock(ptl);
 
3180	}
3181	*nr_pages = remainder;
3182	*position = vaddr;
 
 
3183
3184	return i ? i : -EFAULT;
 
 
 
 
 
 
 
 
3185}
3186
3187unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3188		unsigned long address, unsigned long end, pgprot_t newprot)
 
3189{
3190	struct mm_struct *mm = vma->vm_mm;
3191	unsigned long start = address;
3192	pte_t *ptep;
3193	pte_t pte;
3194	struct hstate *h = hstate_vma(vma);
3195	unsigned long pages = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3196
3197	BUG_ON(address >= end);
3198	flush_cache_range(vma, address, end);
3199
3200	mmu_notifier_invalidate_range_start(mm, start, end);
3201	mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3202	for (; address < end; address += huge_page_size(h)) {
 
 
3203		spinlock_t *ptl;
3204		ptep = huge_pte_offset(mm, address);
3205		if (!ptep)
3206			continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
3207		ptl = huge_pte_lock(h, mm, ptep);
3208		if (huge_pmd_unshare(mm, &address, ptep)) {
 
 
 
 
 
 
3209			pages++;
3210			spin_unlock(ptl);
 
 
3211			continue;
3212		}
3213		if (!huge_pte_none(huge_ptep_get(ptep))) {
3214			pte = huge_ptep_get_and_clear(mm, address, ptep);
3215			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3216			pte = arch_make_huge_pte(pte, vma, NULL, 0);
3217			set_huge_pte_at(mm, address, ptep, pte);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3218			pages++;
 
 
 
 
 
 
 
3219		}
3220		spin_unlock(ptl);
3221	}
3222	/*
3223	 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
3224	 * may have cleared our pud entry and done put_page on the page table:
3225	 * once we release i_mmap_mutex, another task can do the final put_page
3226	 * and that page table be reused and filled with junk.
 
 
 
 
 
 
 
 
 
 
 
 
3227	 */
3228	flush_tlb_range(vma, start, end);
3229	mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3230	mmu_notifier_invalidate_range_end(mm, start, end);
3231
3232	return pages << h->order;
3233}
3234
3235int hugetlb_reserve_pages(struct inode *inode,
 
3236					long from, long to,
3237					struct vm_area_struct *vma,
3238					vm_flags_t vm_flags)
3239{
3240	long ret, chg;
3241	struct hstate *h = hstate_inode(inode);
3242	struct hugepage_subpool *spool = subpool_inode(inode);
3243	struct resv_map *resv_map;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3244
3245	/*
3246	 * Only apply hugepage reservation if asked. At fault time, an
3247	 * attempt will be made for VM_NORESERVE to allocate a page
3248	 * without using reserves
3249	 */
3250	if (vm_flags & VM_NORESERVE)
3251		return 0;
3252
3253	/*
3254	 * Shared mappings base their reservation on the number of pages that
3255	 * are already allocated on behalf of the file. Private mappings need
3256	 * to reserve the full area even if read-only as mprotect() may be
3257	 * called to make the mapping read-write. Assume !vma is a shm mapping
3258	 */
3259	if (!vma || vma->vm_flags & VM_MAYSHARE) {
 
 
 
 
 
3260		resv_map = inode_resv_map(inode);
3261
3262		chg = region_chg(resv_map, from, to);
3263
3264	} else {
 
3265		resv_map = resv_map_alloc();
3266		if (!resv_map)
3267			return -ENOMEM;
3268
3269		chg = to - from;
3270
3271		set_vma_resv_map(vma, resv_map);
3272		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
3273	}
3274
3275	if (chg < 0) {
3276		ret = chg;
3277		goto out_err;
3278	}
3279
3280	/* There must be enough pages in the subpool for the mapping */
3281	if (hugepage_subpool_get_pages(spool, chg)) {
3282		ret = -ENOSPC;
3283		goto out_err;
 
 
 
 
 
 
3284	}
3285
3286	/*
 
 
 
 
 
 
 
 
 
3287	 * Check enough hugepages are available for the reservation.
3288	 * Hand the pages back to the subpool if there are not
3289	 */
3290	ret = hugetlb_acct_memory(h, chg);
3291	if (ret < 0) {
3292		hugepage_subpool_put_pages(spool, chg);
3293		goto out_err;
3294	}
3295
3296	/*
3297	 * Account for the reservations made. Shared mappings record regions
3298	 * that have reservations as they are shared by multiple VMAs.
3299	 * When the last VMA disappears, the region map says how much
3300	 * the reservation was and the page cache tells how much of
3301	 * the reservation was consumed. Private mappings are per-VMA and
3302	 * only the consumed reservations are tracked. When the VMA
3303	 * disappears, the original reservation is the VMA size and the
3304	 * consumed reservations are stored in the map. Hence, nothing
3305	 * else has to be done for private mappings here
3306	 */
3307	if (!vma || vma->vm_flags & VM_MAYSHARE)
3308		region_add(resv_map, from, to);
3309	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3310out_err:
3311	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
 
 
 
 
 
 
 
3312		kref_put(&resv_map->refs, resv_map_release);
3313	return ret;
 
 
3314}
3315
3316void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
 
3317{
3318	struct hstate *h = hstate_inode(inode);
3319	struct resv_map *resv_map = inode_resv_map(inode);
3320	long chg = 0;
3321	struct hugepage_subpool *spool = subpool_inode(inode);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3322
3323	if (resv_map)
3324		chg = region_truncate(resv_map, offset);
3325	spin_lock(&inode->i_lock);
3326	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
3327	spin_unlock(&inode->i_lock);
3328
3329	hugepage_subpool_put_pages(spool, (chg - freed));
3330	hugetlb_acct_memory(h, -(chg - freed));
 
 
 
 
 
 
 
 
 
3331}
3332
3333#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
3334static unsigned long page_table_shareable(struct vm_area_struct *svma,
3335				struct vm_area_struct *vma,
3336				unsigned long addr, pgoff_t idx)
3337{
3338	unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
3339				svma->vm_start;
3340	unsigned long sbase = saddr & PUD_MASK;
3341	unsigned long s_end = sbase + PUD_SIZE;
3342
3343	/* Allow segments to share if only one is marked locked */
3344	unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
3345	unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
3346
3347	/*
3348	 * match the virtual addresses, permission and the alignment of the
3349	 * page table page.
 
 
3350	 */
3351	if (pmd_index(addr) != pmd_index(saddr) ||
3352	    vm_flags != svm_flags ||
3353	    sbase < svma->vm_start || svma->vm_end < s_end)
 
3354		return 0;
3355
3356	return saddr;
3357}
3358
3359static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
3360{
3361	unsigned long base = addr & PUD_MASK;
3362	unsigned long end = base + PUD_SIZE;
3363
 
 
 
 
3364	/*
3365	 * check on proper vm_flags and page table alignment
3366	 */
3367	if (vma->vm_flags & VM_MAYSHARE &&
3368	    vma->vm_start <= base && end <= vma->vm_end)
3369		return 1;
3370	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3371}
3372
3373/*
3374 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
3375 * and returns the corresponding pte. While this is not necessary for the
3376 * !shared pmd case because we can allocate the pmd later as well, it makes the
3377 * code much cleaner. pmd allocation is essential for the shared case because
3378 * pud has to be populated inside the same i_mmap_mutex section - otherwise
3379 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
3380 * bad pmd for sharing.
3381 */
3382pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
 
3383{
3384	struct vm_area_struct *vma = find_vma(mm, addr);
3385	struct address_space *mapping = vma->vm_file->f_mapping;
3386	pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
3387			vma->vm_pgoff;
3388	struct vm_area_struct *svma;
3389	unsigned long saddr;
3390	pte_t *spte = NULL;
3391	pte_t *pte;
3392	spinlock_t *ptl;
3393
3394	if (!vma_shareable(vma, addr))
3395		return (pte_t *)pmd_alloc(mm, pud, addr);
3396
3397	mutex_lock(&mapping->i_mmap_mutex);
3398	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
3399		if (svma == vma)
3400			continue;
3401
3402		saddr = page_table_shareable(svma, vma, addr, idx);
3403		if (saddr) {
3404			spte = huge_pte_offset(svma->vm_mm, saddr);
 
3405			if (spte) {
3406				get_page(virt_to_page(spte));
3407				break;
3408			}
3409		}
3410	}
3411
3412	if (!spte)
3413		goto out;
3414
3415	ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
3416	spin_lock(ptl);
3417	if (pud_none(*pud))
3418		pud_populate(mm, pud,
3419				(pmd_t *)((unsigned long)spte & PAGE_MASK));
3420	else
 
3421		put_page(virt_to_page(spte));
3422	spin_unlock(ptl);
 
3423out:
3424	pte = (pte_t *)pmd_alloc(mm, pud, addr);
3425	mutex_unlock(&mapping->i_mmap_mutex);
3426	return pte;
3427}
3428
3429/*
3430 * unmap huge page backed by shared pte.
3431 *
3432 * Hugetlb pte page is ref counted at the time of mapping.  If pte is shared
3433 * indicated by page_count > 1, unmap is achieved by clearing pud and
3434 * decrementing the ref count. If count == 1, the pte page is not shared.
3435 *
3436 * called with page table lock held.
3437 *
3438 * returns: 1 successfully unmapped a shared pte page
3439 *	    0 the underlying pte page is not shared, or it is the last user
3440 */
3441int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 
3442{
3443	pgd_t *pgd = pgd_offset(mm, *addr);
3444	pud_t *pud = pud_offset(pgd, *addr);
 
3445
 
 
3446	BUG_ON(page_count(virt_to_page(ptep)) == 0);
3447	if (page_count(virt_to_page(ptep)) == 1)
3448		return 0;
3449
3450	pud_clear(pud);
3451	put_page(virt_to_page(ptep));
3452	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
3453	return 1;
3454}
3455#define want_pmd_share()	(1)
3456#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3457pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
 
 
3458{
3459	return NULL;
3460}
3461#define want_pmd_share()	(0)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3462#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
3463
3464#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
3465pte_t *huge_pte_alloc(struct mm_struct *mm,
3466			unsigned long addr, unsigned long sz)
3467{
3468	pgd_t *pgd;
 
3469	pud_t *pud;
3470	pte_t *pte = NULL;
3471
3472	pgd = pgd_offset(mm, addr);
3473	pud = pud_alloc(mm, pgd, addr);
 
 
 
3474	if (pud) {
3475		if (sz == PUD_SIZE) {
3476			pte = (pte_t *)pud;
3477		} else {
3478			BUG_ON(sz != PMD_SIZE);
3479			if (want_pmd_share() && pud_none(*pud))
3480				pte = huge_pmd_share(mm, addr, pud);
3481			else
3482				pte = (pte_t *)pmd_alloc(mm, pud, addr);
3483		}
3484	}
3485	BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
 
 
 
 
 
3486
3487	return pte;
3488}
3489
3490pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 
 
 
 
 
 
 
 
 
 
3491{
3492	pgd_t *pgd;
 
3493	pud_t *pud;
3494	pmd_t *pmd = NULL;
3495
3496	pgd = pgd_offset(mm, addr);
3497	if (pgd_present(*pgd)) {
3498		pud = pud_offset(pgd, addr);
3499		if (pud_present(*pud)) {
3500			if (pud_huge(*pud))
3501				return (pte_t *)pud;
3502			pmd = pmd_offset(pud, addr);
3503		}
3504	}
3505	return (pte_t *) pmd;
3506}
3507
3508struct page *
3509follow_huge_pmd(struct mm_struct *mm, unsigned long address,
3510		pmd_t *pmd, int write)
3511{
3512	struct page *page;
 
 
3513
3514	page = pte_page(*(pte_t *)pmd);
3515	if (page)
3516		page += ((address & ~PMD_MASK) >> PAGE_SHIFT);
3517	return page;
3518}
3519
3520struct page *
3521follow_huge_pud(struct mm_struct *mm, unsigned long address,
3522		pud_t *pud, int write)
 
 
 
 
 
3523{
3524	struct page *page;
3525
3526	page = pte_page(*(pte_t *)pud);
3527	if (page)
3528		page += ((address & ~PUD_MASK) >> PAGE_SHIFT);
3529	return page;
 
 
3530}
3531
3532#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3533
3534/* Can be overriden by architectures */
3535struct page * __weak
3536follow_huge_pud(struct mm_struct *mm, unsigned long address,
3537	       pud_t *pud, int write)
3538{
3539	BUG();
3540	return NULL;
 
 
 
3541}
3542
3543#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
3544
3545#ifdef CONFIG_MEMORY_FAILURE
3546
3547/* Should be called in hugetlb_lock */
3548static int is_hugepage_on_freelist(struct page *hpage)
 
3549{
3550	struct page *page;
3551	struct page *tmp;
3552	struct hstate *h = page_hstate(hpage);
3553	int nid = page_to_nid(hpage);
3554
3555	list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
3556		if (page == hpage)
3557			return 1;
3558	return 0;
 
 
 
 
 
 
 
 
3559}
3560
3561/*
3562 * This function is called from memory failure code.
3563 * Assume the caller holds page lock of the head page.
3564 */
3565int dequeue_hwpoisoned_huge_page(struct page *hpage)
3566{
3567	struct hstate *h = page_hstate(hpage);
3568	int nid = page_to_nid(hpage);
3569	int ret = -EBUSY;
3570
3571	spin_lock(&hugetlb_lock);
3572	if (is_hugepage_on_freelist(hpage)) {
3573		/*
3574		 * Hwpoisoned hugepage isn't linked to activelist or freelist,
3575		 * but dangling hpage->lru can trigger list-debug warnings
3576		 * (this happens when we call unpoison_memory() on it),
3577		 * so let it point to itself with list_del_init().
3578		 */
3579		list_del_init(&hpage->lru);
3580		set_page_refcounted(hpage);
3581		h->free_huge_pages--;
3582		h->free_huge_pages_node[nid]--;
3583		ret = 0;
3584	}
3585	spin_unlock(&hugetlb_lock);
3586	return ret;
3587}
3588#endif
3589
3590bool isolate_huge_page(struct page *page, struct list_head *list)
 
3591{
3592	VM_BUG_ON_PAGE(!PageHead(page), page);
3593	if (!get_page_unless_zero(page))
3594		return false;
3595	spin_lock(&hugetlb_lock);
3596	list_move_tail(&page->lru, list);
3597	spin_unlock(&hugetlb_lock);
3598	return true;
3599}
3600
3601void putback_active_hugepage(struct page *page)
3602{
3603	VM_BUG_ON_PAGE(!PageHead(page), page);
3604	spin_lock(&hugetlb_lock);
3605	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
3606	spin_unlock(&hugetlb_lock);
3607	put_page(page);
3608}
3609
3610bool is_hugepage_active(struct page *page)
3611{
3612	VM_BUG_ON_PAGE(!PageHuge(page), page);
 
 
 
 
3613	/*
3614	 * This function can be called for a tail page because the caller,
3615	 * scan_movable_pages, scans through a given pfn-range which typically
3616	 * covers one memory block. In systems using gigantic hugepage (1GB
3617	 * for x86_64,) a hugepage is larger than a memory block, and we don't
3618	 * support migrating such large hugepages for now, so return false
3619	 * when called for tail pages.
 
 
3620	 */
3621	if (PageTail(page))
3622		return false;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3623	/*
3624	 * Refcount of a hwpoisoned hugepages is 1, but they are not active,
3625	 * so we should return false for them.
3626	 */
3627	if (unlikely(PageHWPoison(page)))
3628		return false;
3629	return page_count(page) > 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3630}