hugetlb.c 82.3 KB
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Linus Torvalds 已提交
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/*
 * Generic hugetlb support.
 * (C) William Irwin, April 2004
 */
#include <linux/list.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
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#include <linux/seq_file.h>
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#include <linux/sysctl.h>
#include <linux/highmem.h>
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#include <linux/mmu_notifier.h>
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#include <linux/nodemask.h>
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#include <linux/pagemap.h>
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#include <linux/mempolicy.h>
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#include <linux/cpuset.h>
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#include <linux/mutex.h>
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#include <linux/bootmem.h>
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#include <linux/sysfs.h>
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#include <linux/slab.h>
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#include <linux/rmap.h>
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#include <linux/swap.h>
#include <linux/swapops.h>
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#include <asm/page.h>
#include <asm/pgtable.h>
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#include <asm/tlb.h>
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#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <linux/hugetlb_cgroup.h>
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#include <linux/node.h>
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#include "internal.h"
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const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
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static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
unsigned long hugepages_treat_as_movable;
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int hugetlb_max_hstate __read_mostly;
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unsigned int default_hstate_idx;
struct hstate hstates[HUGE_MAX_HSTATE];

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__initdata LIST_HEAD(huge_boot_pages);

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/* for command line parsing */
static struct hstate * __initdata parsed_hstate;
static unsigned long __initdata default_hstate_max_huge_pages;
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static unsigned long __initdata default_hstate_size;
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/*
 * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
 */
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DEFINE_SPINLOCK(hugetlb_lock);
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static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
{
	bool free = (spool->count == 0) && (spool->used_hpages == 0);

	spin_unlock(&spool->lock);

	/* If no pages are used, and no other handles to the subpool
	 * remain, free the subpool the subpool remain */
	if (free)
		kfree(spool);
}

struct hugepage_subpool *hugepage_new_subpool(long nr_blocks)
{
	struct hugepage_subpool *spool;

	spool = kmalloc(sizeof(*spool), GFP_KERNEL);
	if (!spool)
		return NULL;

	spin_lock_init(&spool->lock);
	spool->count = 1;
	spool->max_hpages = nr_blocks;
	spool->used_hpages = 0;

	return spool;
}

void hugepage_put_subpool(struct hugepage_subpool *spool)
{
	spin_lock(&spool->lock);
	BUG_ON(!spool->count);
	spool->count--;
	unlock_or_release_subpool(spool);
}

static int hugepage_subpool_get_pages(struct hugepage_subpool *spool,
				      long delta)
{
	int ret = 0;

	if (!spool)
		return 0;

	spin_lock(&spool->lock);
	if ((spool->used_hpages + delta) <= spool->max_hpages) {
		spool->used_hpages += delta;
	} else {
		ret = -ENOMEM;
	}
	spin_unlock(&spool->lock);

	return ret;
}

static void hugepage_subpool_put_pages(struct hugepage_subpool *spool,
				       long delta)
{
	if (!spool)
		return;

	spin_lock(&spool->lock);
	spool->used_hpages -= delta;
	/* If hugetlbfs_put_super couldn't free spool due to
	* an outstanding quota reference, free it now. */
	unlock_or_release_subpool(spool);
}

static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
{
	return HUGETLBFS_SB(inode->i_sb)->spool;
}

static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
{
	return subpool_inode(vma->vm_file->f_dentry->d_inode);
}

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/*
 * Region tracking -- allows tracking of reservations and instantiated pages
 *                    across the pages in a mapping.
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 *
 * The region data structures are protected by a combination of the mmap_sem
 * and the hugetlb_instantion_mutex.  To access or modify a region the caller
 * must either hold the mmap_sem for write, or the mmap_sem for read and
 * the hugetlb_instantiation mutex:
 *
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 *	down_write(&mm->mmap_sem);
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 * or
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 *	down_read(&mm->mmap_sem);
 *	mutex_lock(&hugetlb_instantiation_mutex);
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 */
struct file_region {
	struct list_head link;
	long from;
	long to;
};

static long region_add(struct list_head *head, long f, long t)
{
	struct file_region *rg, *nrg, *trg;

	/* Locate the region we are either in or before. */
	list_for_each_entry(rg, head, link)
		if (f <= rg->to)
			break;

	/* Round our left edge to the current segment if it encloses us. */
	if (f > rg->from)
		f = rg->from;

	/* Check for and consume any regions we now overlap with. */
	nrg = rg;
	list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
		if (&rg->link == head)
			break;
		if (rg->from > t)
			break;

		/* If this area reaches higher then extend our area to
		 * include it completely.  If this is not the first area
		 * which we intend to reuse, free it. */
		if (rg->to > t)
			t = rg->to;
		if (rg != nrg) {
			list_del(&rg->link);
			kfree(rg);
		}
	}
	nrg->from = f;
	nrg->to = t;
	return 0;
}

static long region_chg(struct list_head *head, long f, long t)
{
	struct file_region *rg, *nrg;
	long chg = 0;

	/* Locate the region we are before or in. */
	list_for_each_entry(rg, head, link)
		if (f <= rg->to)
			break;

	/* If we are below the current region then a new region is required.
	 * Subtle, allocate a new region at the position but make it zero
	 * size such that we can guarantee to record the reservation. */
	if (&rg->link == head || t < rg->from) {
		nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
		if (!nrg)
			return -ENOMEM;
		nrg->from = f;
		nrg->to   = f;
		INIT_LIST_HEAD(&nrg->link);
		list_add(&nrg->link, rg->link.prev);

		return t - f;
	}

	/* Round our left edge to the current segment if it encloses us. */
	if (f > rg->from)
		f = rg->from;
	chg = t - f;

	/* Check for and consume any regions we now overlap with. */
	list_for_each_entry(rg, rg->link.prev, link) {
		if (&rg->link == head)
			break;
		if (rg->from > t)
			return chg;

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		/* We overlap with this area, if it extends further than
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		 * us then we must extend ourselves.  Account for its
		 * existing reservation. */
		if (rg->to > t) {
			chg += rg->to - t;
			t = rg->to;
		}
		chg -= rg->to - rg->from;
	}
	return chg;
}

static long region_truncate(struct list_head *head, long end)
{
	struct file_region *rg, *trg;
	long chg = 0;

	/* Locate the region we are either in or before. */
	list_for_each_entry(rg, head, link)
		if (end <= rg->to)
			break;
	if (&rg->link == head)
		return 0;

	/* If we are in the middle of a region then adjust it. */
	if (end > rg->from) {
		chg = rg->to - end;
		rg->to = end;
		rg = list_entry(rg->link.next, typeof(*rg), link);
	}

	/* Drop any remaining regions. */
	list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
		if (&rg->link == head)
			break;
		chg += rg->to - rg->from;
		list_del(&rg->link);
		kfree(rg);
	}
	return chg;
}

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static long region_count(struct list_head *head, long f, long t)
{
	struct file_region *rg;
	long chg = 0;

	/* Locate each segment we overlap with, and count that overlap. */
	list_for_each_entry(rg, head, link) {
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		long seg_from;
		long seg_to;
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		if (rg->to <= f)
			continue;
		if (rg->from >= t)
			break;

		seg_from = max(rg->from, f);
		seg_to = min(rg->to, t);

		chg += seg_to - seg_from;
	}

	return chg;
}

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/*
 * Convert the address within this vma to the page offset within
 * the mapping, in pagecache page units; huge pages here.
 */
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static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
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{
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	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
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}

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pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
				     unsigned long address)
{
	return vma_hugecache_offset(hstate_vma(vma), vma, address);
}

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/*
 * Return the size of the pages allocated when backing a VMA. In the majority
 * cases this will be same size as used by the page table entries.
 */
unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
{
	struct hstate *hstate;

	if (!is_vm_hugetlb_page(vma))
		return PAGE_SIZE;

	hstate = hstate_vma(vma);

	return 1UL << (hstate->order + PAGE_SHIFT);
}
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EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
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/*
 * Return the page size being used by the MMU to back a VMA. In the majority
 * of cases, the page size used by the kernel matches the MMU size. On
 * architectures where it differs, an architecture-specific version of this
 * function is required.
 */
#ifndef vma_mmu_pagesize
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
	return vma_kernel_pagesize(vma);
}
#endif

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/*
 * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
 * bits of the reservation map pointer, which are always clear due to
 * alignment.
 */
#define HPAGE_RESV_OWNER    (1UL << 0)
#define HPAGE_RESV_UNMAPPED (1UL << 1)
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#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
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/*
 * These helpers are used to track how many pages are reserved for
 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
 * is guaranteed to have their future faults succeed.
 *
 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
 * the reserve counters are updated with the hugetlb_lock held. It is safe
 * to reset the VMA at fork() time as it is not in use yet and there is no
 * chance of the global counters getting corrupted as a result of the values.
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 *
 * The private mapping reservation is represented in a subtly different
 * manner to a shared mapping.  A shared mapping has a region map associated
 * with the underlying file, this region map represents the backing file
 * pages which have ever had a reservation assigned which this persists even
 * after the page is instantiated.  A private mapping has a region map
 * associated with the original mmap which is attached to all VMAs which
 * reference it, this region map represents those offsets which have consumed
 * reservation ie. where pages have been instantiated.
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 */
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static unsigned long get_vma_private_data(struct vm_area_struct *vma)
{
	return (unsigned long)vma->vm_private_data;
}

static void set_vma_private_data(struct vm_area_struct *vma,
							unsigned long value)
{
	vma->vm_private_data = (void *)value;
}

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struct resv_map {
	struct kref refs;
	struct list_head regions;
};

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static struct resv_map *resv_map_alloc(void)
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{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
	if (!resv_map)
		return NULL;

	kref_init(&resv_map->refs);
	INIT_LIST_HEAD(&resv_map->regions);

	return resv_map;
}

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static void resv_map_release(struct kref *ref)
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{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);

	/* Clear out any active regions before we release the map. */
	region_truncate(&resv_map->regions, 0);
	kfree(resv_map);
}

static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
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{
	VM_BUG_ON(!is_vm_hugetlb_page(vma));
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	if (!(vma->vm_flags & VM_MAYSHARE))
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		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
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	return NULL;
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}

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static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
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{
	VM_BUG_ON(!is_vm_hugetlb_page(vma));
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	VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
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	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
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}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
	VM_BUG_ON(!is_vm_hugetlb_page(vma));
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	VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
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	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
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}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
	VM_BUG_ON(!is_vm_hugetlb_page(vma));
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	return (get_vma_private_data(vma) & flag) != 0;
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}

/* Decrement the reserved pages in the hugepage pool by one */
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static void decrement_hugepage_resv_vma(struct hstate *h,
			struct vm_area_struct *vma)
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{
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	if (vma->vm_flags & VM_NORESERVE)
		return;

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	if (vma->vm_flags & VM_MAYSHARE) {
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		/* Shared mappings always use reserves */
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		h->resv_huge_pages--;
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	} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
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		/*
		 * Only the process that called mmap() has reserves for
		 * private mappings.
		 */
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		h->resv_huge_pages--;
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	}
}

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/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
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void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
	VM_BUG_ON(!is_vm_hugetlb_page(vma));
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	if (!(vma->vm_flags & VM_MAYSHARE))
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		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
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static int vma_has_reserves(struct vm_area_struct *vma)
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{
467
	if (vma->vm_flags & VM_MAYSHARE)
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		return 1;
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return 1;
	return 0;
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}

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static void copy_gigantic_page(struct page *dst, struct page *src)
{
	int i;
	struct hstate *h = page_hstate(src);
	struct page *dst_base = dst;
	struct page *src_base = src;

	for (i = 0; i < pages_per_huge_page(h); ) {
		cond_resched();
		copy_highpage(dst, src);

		i++;
		dst = mem_map_next(dst, dst_base, i);
		src = mem_map_next(src, src_base, i);
	}
}

void copy_huge_page(struct page *dst, struct page *src)
{
	int i;
	struct hstate *h = page_hstate(src);

	if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
		copy_gigantic_page(dst, src);
		return;
	}

	might_sleep();
	for (i = 0; i < pages_per_huge_page(h); i++) {
		cond_resched();
		copy_highpage(dst + i, src + i);
	}
}

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static void enqueue_huge_page(struct hstate *h, struct page *page)
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{
	int nid = page_to_nid(page);
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	list_move(&page->lru, &h->hugepage_freelists[nid]);
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	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
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}

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static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
{
	struct page *page;

	if (list_empty(&h->hugepage_freelists[nid]))
		return NULL;
	page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
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	list_move(&page->lru, &h->hugepage_activelist);
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	set_page_refcounted(page);
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	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

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static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
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				unsigned long address, int avoid_reserve)
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{
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	struct page *page = NULL;
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	struct mempolicy *mpol;
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	nodemask_t *nodemask;
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	struct zonelist *zonelist;
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	struct zone *zone;
	struct zoneref *z;
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	unsigned int cpuset_mems_cookie;
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retry_cpuset:
	cpuset_mems_cookie = get_mems_allowed();
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	zonelist = huge_zonelist(vma, address,
					htlb_alloc_mask, &mpol, &nodemask);
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	/*
	 * A child process with MAP_PRIVATE mappings created by their parent
	 * have no page reserves. This check ensures that reservations are
	 * not "stolen". The child may still get SIGKILLed
	 */
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	if (!vma_has_reserves(vma) &&
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			h->free_huge_pages - h->resv_huge_pages == 0)
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		goto err;
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	/* If reserves cannot be used, ensure enough pages are in the pool */
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	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
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		goto err;
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	for_each_zone_zonelist_nodemask(zone, z, zonelist,
						MAX_NR_ZONES - 1, nodemask) {
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		if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
			page = dequeue_huge_page_node(h, zone_to_nid(zone));
			if (page) {
				if (!avoid_reserve)
					decrement_hugepage_resv_vma(h, vma);
				break;
			}
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		}
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	}
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	mpol_cond_put(mpol);
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	if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
		goto retry_cpuset;
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	return page;
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err:
	mpol_cond_put(mpol);
	return NULL;
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}

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static void update_and_free_page(struct hstate *h, struct page *page)
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{
	int i;
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	VM_BUG_ON(h->order >= MAX_ORDER);

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	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
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		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
				1 << PG_active | 1 << PG_reserved |
				1 << PG_private | 1 << PG_writeback);
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	}
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	VM_BUG_ON(hugetlb_cgroup_from_page(page));
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	set_compound_page_dtor(page, NULL);
	set_page_refcounted(page);
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	arch_release_hugepage(page);
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	__free_pages(page, huge_page_order(h));
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}

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struct hstate *size_to_hstate(unsigned long size)
{
	struct hstate *h;

	for_each_hstate(h) {
		if (huge_page_size(h) == size)
			return h;
	}
	return NULL;
}

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static void free_huge_page(struct page *page)
{
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	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
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	struct hstate *h = page_hstate(page);
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	int nid = page_to_nid(page);
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	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
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	set_page_private(page, 0);
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	page->mapping = NULL;
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	BUG_ON(page_count(page));
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	BUG_ON(page_mapcount(page));
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	spin_lock(&hugetlb_lock);
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	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
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	if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
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		/* remove the page from active list */
		list_del(&page->lru);
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		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
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	} else {
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		arch_clear_hugepage_flags(page);
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		enqueue_huge_page(h, page);
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	}
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	spin_unlock(&hugetlb_lock);
643
	hugepage_subpool_put_pages(spool, 1);
644 645
}

646
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
647
{
648
	INIT_LIST_HEAD(&page->lru);
649 650
	set_compound_page_dtor(page, free_huge_page);
	spin_lock(&hugetlb_lock);
651
	set_hugetlb_cgroup(page, NULL);
652 653
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
654 655 656 657
	spin_unlock(&hugetlb_lock);
	put_page(page); /* free it into the hugepage allocator */
}

658 659 660 661 662 663 664 665 666 667 668
static void prep_compound_gigantic_page(struct page *page, unsigned long order)
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

	/* we rely on prep_new_huge_page to set the destructor */
	set_compound_order(page, order);
	__SetPageHead(page);
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
		__SetPageTail(p);
669
		set_page_count(p, 0);
670 671 672 673
		p->first_page = page;
	}
}

A
Andrew Morton 已提交
674 675 676 677 678
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
679 680 681 682 683 684 685 686 687 688 689 690
int PageHuge(struct page *page)
{
	compound_page_dtor *dtor;

	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
	dtor = get_compound_page_dtor(page);

	return dtor == free_huge_page;
}
691 692
EXPORT_SYMBOL_GPL(PageHuge);

693
static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
L
Linus Torvalds 已提交
694 695
{
	struct page *page;
696

697 698 699
	if (h->order >= MAX_ORDER)
		return NULL;

700
	page = alloc_pages_exact_node(nid,
701 702
		htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
						__GFP_REPEAT|__GFP_NOWARN,
703
		huge_page_order(h));
L
Linus Torvalds 已提交
704
	if (page) {
705
		if (arch_prepare_hugepage(page)) {
706
			__free_pages(page, huge_page_order(h));
707
			return NULL;
708
		}
709
		prep_new_huge_page(h, page, nid);
L
Linus Torvalds 已提交
710
	}
711 712 713 714

	return page;
}

715
/*
716 717 718 719 720
 * common helper functions for hstate_next_node_to_{alloc|free}.
 * We may have allocated or freed a huge page based on a different
 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
 * be outside of *nodes_allowed.  Ensure that we use an allowed
 * node for alloc or free.
721
 */
722
static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
723
{
724
	nid = next_node(nid, *nodes_allowed);
725
	if (nid == MAX_NUMNODES)
726
		nid = first_node(*nodes_allowed);
727 728 729 730 731
	VM_BUG_ON(nid >= MAX_NUMNODES);

	return nid;
}

732 733 734 735 736 737 738
static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
{
	if (!node_isset(nid, *nodes_allowed))
		nid = next_node_allowed(nid, nodes_allowed);
	return nid;
}

739
/*
740 741 742 743
 * returns the previously saved node ["this node"] from which to
 * allocate a persistent huge page for the pool and advance the
 * next node from which to allocate, handling wrap at end of node
 * mask.
744
 */
745 746
static int hstate_next_node_to_alloc(struct hstate *h,
					nodemask_t *nodes_allowed)
747
{
748 749 750 751 752 753
	int nid;

	VM_BUG_ON(!nodes_allowed);

	nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
	h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
754 755

	return nid;
756 757
}

758
static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
759 760 761 762 763 764
{
	struct page *page;
	int start_nid;
	int next_nid;
	int ret = 0;

765
	start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
766
	next_nid = start_nid;
767 768

	do {
769
		page = alloc_fresh_huge_page_node(h, next_nid);
770
		if (page) {
771
			ret = 1;
772 773
			break;
		}
774
		next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
775
	} while (next_nid != start_nid);
776

777 778 779 780 781
	if (ret)
		count_vm_event(HTLB_BUDDY_PGALLOC);
	else
		count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);

782
	return ret;
L
Linus Torvalds 已提交
783 784
}

785
/*
786 787 788 789
 * helper for free_pool_huge_page() - return the previously saved
 * node ["this node"] from which to free a huge page.  Advance the
 * next node id whether or not we find a free huge page to free so
 * that the next attempt to free addresses the next node.
790
 */
791
static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
792
{
793 794 795 796 797 798
	int nid;

	VM_BUG_ON(!nodes_allowed);

	nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
	h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
799 800

	return nid;
801 802 803 804 805 806 807 808
}

/*
 * Free huge page from pool from next node to free.
 * Attempt to keep persistent huge pages more or less
 * balanced over allowed nodes.
 * Called with hugetlb_lock locked.
 */
809 810
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
811 812 813 814 815
{
	int start_nid;
	int next_nid;
	int ret = 0;

816
	start_nid = hstate_next_node_to_free(h, nodes_allowed);
817 818 819
	next_nid = start_nid;

	do {
820 821 822 823 824 825
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
		if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
		    !list_empty(&h->hugepage_freelists[next_nid])) {
826 827 828 829 830 831
			struct page *page =
				list_entry(h->hugepage_freelists[next_nid].next,
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
			h->free_huge_pages_node[next_nid]--;
832 833 834 835
			if (acct_surplus) {
				h->surplus_huge_pages--;
				h->surplus_huge_pages_node[next_nid]--;
			}
836 837
			update_and_free_page(h, page);
			ret = 1;
838
			break;
839
		}
840
		next_nid = hstate_next_node_to_free(h, nodes_allowed);
841
	} while (next_nid != start_nid);
842 843 844 845

	return ret;
}

846
static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
847 848
{
	struct page *page;
849
	unsigned int r_nid;
850

851 852 853
	if (h->order >= MAX_ORDER)
		return NULL;

854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877
	/*
	 * Assume we will successfully allocate the surplus page to
	 * prevent racing processes from causing the surplus to exceed
	 * overcommit
	 *
	 * This however introduces a different race, where a process B
	 * tries to grow the static hugepage pool while alloc_pages() is
	 * called by process A. B will only examine the per-node
	 * counters in determining if surplus huge pages can be
	 * converted to normal huge pages in adjust_pool_surplus(). A
	 * won't be able to increment the per-node counter, until the
	 * lock is dropped by B, but B doesn't drop hugetlb_lock until
	 * no more huge pages can be converted from surplus to normal
	 * state (and doesn't try to convert again). Thus, we have a
	 * case where a surplus huge page exists, the pool is grown, and
	 * the surplus huge page still exists after, even though it
	 * should just have been converted to a normal huge page. This
	 * does not leak memory, though, as the hugepage will be freed
	 * once it is out of use. It also does not allow the counters to
	 * go out of whack in adjust_pool_surplus() as we don't modify
	 * the node values until we've gotten the hugepage and only the
	 * per-node value is checked there.
	 */
	spin_lock(&hugetlb_lock);
878
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
879 880 881
		spin_unlock(&hugetlb_lock);
		return NULL;
	} else {
882 883
		h->nr_huge_pages++;
		h->surplus_huge_pages++;
884 885 886
	}
	spin_unlock(&hugetlb_lock);

887 888 889 890 891 892 893 894
	if (nid == NUMA_NO_NODE)
		page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
				   __GFP_REPEAT|__GFP_NOWARN,
				   huge_page_order(h));
	else
		page = alloc_pages_exact_node(nid,
			htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
			__GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
895

896 897
	if (page && arch_prepare_hugepage(page)) {
		__free_pages(page, huge_page_order(h));
898
		page = NULL;
899 900
	}

901
	spin_lock(&hugetlb_lock);
902
	if (page) {
903
		INIT_LIST_HEAD(&page->lru);
904
		r_nid = page_to_nid(page);
905
		set_compound_page_dtor(page, free_huge_page);
906
		set_hugetlb_cgroup(page, NULL);
907 908 909
		/*
		 * We incremented the global counters already
		 */
910 911
		h->nr_huge_pages_node[r_nid]++;
		h->surplus_huge_pages_node[r_nid]++;
912
		__count_vm_event(HTLB_BUDDY_PGALLOC);
913
	} else {
914 915
		h->nr_huge_pages--;
		h->surplus_huge_pages--;
916
		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
917
	}
918
	spin_unlock(&hugetlb_lock);
919 920 921 922

	return page;
}

923 924 925 926 927 928 929 930 931 932 933 934 935
/*
 * This allocation function is useful in the context where vma is irrelevant.
 * E.g. soft-offlining uses this function because it only cares physical
 * address of error page.
 */
struct page *alloc_huge_page_node(struct hstate *h, int nid)
{
	struct page *page;

	spin_lock(&hugetlb_lock);
	page = dequeue_huge_page_node(h, nid);
	spin_unlock(&hugetlb_lock);

936
	if (!page)
937 938 939 940 941
		page = alloc_buddy_huge_page(h, nid);

	return page;
}

942
/*
L
Lucas De Marchi 已提交
943
 * Increase the hugetlb pool such that it can accommodate a reservation
944 945
 * of size 'delta'.
 */
946
static int gather_surplus_pages(struct hstate *h, int delta)
947 948 949 950 951
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
952
	bool alloc_ok = true;
953

954
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
955
	if (needed <= 0) {
956
		h->resv_huge_pages += delta;
957
		return 0;
958
	}
959 960 961 962 963 964 965 966

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
967
		page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
968 969 970 971
		if (!page) {
			alloc_ok = false;
			break;
		}
972 973
		list_add(&page->lru, &surplus_list);
	}
974
	allocated += i;
975 976 977 978 979 980

	/*
	 * After retaking hugetlb_lock, we need to recalculate 'needed'
	 * because either resv_huge_pages or free_huge_pages may have changed.
	 */
	spin_lock(&hugetlb_lock);
981 982
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
983 984 985 986 987 988 989 990 991 992
	if (needed > 0) {
		if (alloc_ok)
			goto retry;
		/*
		 * We were not able to allocate enough pages to
		 * satisfy the entire reservation so we free what
		 * we've allocated so far.
		 */
		goto free;
	}
993 994
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
995
	 * needed to accommodate the reservation.  Add the appropriate number
996
	 * of pages to the hugetlb pool and free the extras back to the buddy
997 998 999
	 * allocator.  Commit the entire reservation here to prevent another
	 * process from stealing the pages as they are added to the pool but
	 * before they are reserved.
1000 1001
	 */
	needed += allocated;
1002
	h->resv_huge_pages += delta;
1003
	ret = 0;
1004

1005
	/* Free the needed pages to the hugetlb pool */
1006
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1007 1008
		if ((--needed) < 0)
			break;
1009 1010 1011 1012 1013 1014
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
		VM_BUG_ON(page_count(page));
1015
		enqueue_huge_page(h, page);
1016
	}
1017
free:
1018
	spin_unlock(&hugetlb_lock);
1019 1020 1021 1022

	/* Free unnecessary surplus pages to the buddy allocator */
	if (!list_empty(&surplus_list)) {
		list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1023
			put_page(page);
1024
		}
1025
	}
1026
	spin_lock(&hugetlb_lock);
1027 1028 1029 1030 1031 1032 1033 1034

	return ret;
}

/*
 * When releasing a hugetlb pool reservation, any surplus pages that were
 * allocated to satisfy the reservation must be explicitly freed if they were
 * never used.
1035
 * Called with hugetlb_lock held.
1036
 */
1037 1038
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
1039 1040 1041
{
	unsigned long nr_pages;

1042
	/* Uncommit the reservation */
1043
	h->resv_huge_pages -= unused_resv_pages;
1044

1045 1046 1047 1048
	/* Cannot return gigantic pages currently */
	if (h->order >= MAX_ORDER)
		return;

1049
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1050

1051 1052
	/*
	 * We want to release as many surplus pages as possible, spread
1053 1054 1055 1056 1057
	 * evenly across all nodes with memory. Iterate across these nodes
	 * until we can no longer free unreserved surplus pages. This occurs
	 * when the nodes with surplus pages have no free pages.
	 * free_pool_huge_page() will balance the the freed pages across the
	 * on-line nodes with memory and will handle the hstate accounting.
1058 1059
	 */
	while (nr_pages--) {
1060
		if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
1061
			break;
1062 1063 1064
	}
}

1065 1066 1067
/*
 * Determine if the huge page at addr within the vma has an associated
 * reservation.  Where it does not we will need to logically increase
1068 1069 1070 1071 1072 1073
 * reservation and actually increase subpool usage before an allocation
 * can occur.  Where any new reservation would be required the
 * reservation change is prepared, but not committed.  Once the page
 * has been allocated from the subpool and instantiated the change should
 * be committed via vma_commit_reservation.  No action is required on
 * failure.
1074
 */
1075
static long vma_needs_reservation(struct hstate *h,
1076
			struct vm_area_struct *vma, unsigned long addr)
1077 1078 1079 1080
{
	struct address_space *mapping = vma->vm_file->f_mapping;
	struct inode *inode = mapping->host;

1081
	if (vma->vm_flags & VM_MAYSHARE) {
1082
		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1083 1084 1085
		return region_chg(&inode->i_mapping->private_list,
							idx, idx + 1);

1086 1087
	} else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
		return 1;
1088

1089
	} else  {
1090
		long err;
1091
		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1092 1093 1094 1095 1096 1097 1098
		struct resv_map *reservations = vma_resv_map(vma);

		err = region_chg(&reservations->regions, idx, idx + 1);
		if (err < 0)
			return err;
		return 0;
	}
1099
}
1100 1101
static void vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
1102 1103 1104 1105
{
	struct address_space *mapping = vma->vm_file->f_mapping;
	struct inode *inode = mapping->host;

1106
	if (vma->vm_flags & VM_MAYSHARE) {
1107
		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1108
		region_add(&inode->i_mapping->private_list, idx, idx + 1);
1109 1110

	} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
1111
		pgoff_t idx = vma_hugecache_offset(h, vma, addr);
1112 1113 1114 1115
		struct resv_map *reservations = vma_resv_map(vma);

		/* Mark this page used in the map. */
		region_add(&reservations->regions, idx, idx + 1);
1116 1117 1118
	}
}

1119
static struct page *alloc_huge_page(struct vm_area_struct *vma,
1120
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
1121
{
1122
	struct hugepage_subpool *spool = subpool_vma(vma);
1123
	struct hstate *h = hstate_vma(vma);
1124
	struct page *page;
1125
	long chg;
1126 1127
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
1128

1129
	idx = hstate_index(h);
1130
	/*
1131 1132 1133 1134 1135 1136
	 * Processes that did not create the mapping will have no
	 * reserves and will not have accounted against subpool
	 * limit. Check that the subpool limit can be made before
	 * satisfying the allocation MAP_NORESERVE mappings may also
	 * need pages and subpool limit allocated allocated if no reserve
	 * mapping overlaps.
1137
	 */
1138
	chg = vma_needs_reservation(h, vma, addr);
1139
	if (chg < 0)
1140
		return ERR_PTR(-ENOMEM);
1141
	if (chg)
1142
		if (hugepage_subpool_get_pages(spool, chg))
1143
			return ERR_PTR(-ENOSPC);
L
Linus Torvalds 已提交
1144

1145 1146 1147 1148 1149
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
	if (ret) {
		hugepage_subpool_put_pages(spool, chg);
		return ERR_PTR(-ENOSPC);
	}
L
Linus Torvalds 已提交
1150
	spin_lock(&hugetlb_lock);
1151
	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
1152 1153 1154 1155 1156 1157 1158
	if (page) {
		/* update page cgroup details */
		hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h),
					     h_cg, page);
		spin_unlock(&hugetlb_lock);
	} else {
		spin_unlock(&hugetlb_lock);
1159
		page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
K
Ken Chen 已提交
1160
		if (!page) {
1161 1162 1163
			hugetlb_cgroup_uncharge_cgroup(idx,
						       pages_per_huge_page(h),
						       h_cg);
1164
			hugepage_subpool_put_pages(spool, chg);
1165
			return ERR_PTR(-ENOSPC);
K
Ken Chen 已提交
1166
		}
1167
		spin_lock(&hugetlb_lock);
1168 1169
		hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h),
					     h_cg, page);
1170 1171
		list_move(&page->lru, &h->hugepage_activelist);
		spin_unlock(&hugetlb_lock);
K
Ken Chen 已提交
1172
	}
1173

1174
	set_page_private(page, (unsigned long)spool);
1175

1176
	vma_commit_reservation(h, vma, addr);
1177
	return page;
1178 1179
}

1180
int __weak alloc_bootmem_huge_page(struct hstate *h)
1181 1182
{
	struct huge_bootmem_page *m;
1183
	int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
1184 1185 1186 1187 1188

	while (nr_nodes) {
		void *addr;

		addr = __alloc_bootmem_node_nopanic(
1189
				NODE_DATA(hstate_next_node_to_alloc(h,
1190
						&node_states[N_HIGH_MEMORY])),
1191 1192 1193 1194 1195 1196 1197 1198 1199
				huge_page_size(h), huge_page_size(h), 0);

		if (addr) {
			/*
			 * Use the beginning of the huge page to store the
			 * huge_bootmem_page struct (until gather_bootmem
			 * puts them into the mem_map).
			 */
			m = addr;
1200
			goto found;
1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213
		}
		nr_nodes--;
	}
	return 0;

found:
	BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
	/* Put them into a private list first because mem_map is not up yet */
	list_add(&m->list, &huge_boot_pages);
	m->hstate = h;
	return 1;
}

1214 1215 1216 1217 1218 1219 1220 1221
static void prep_compound_huge_page(struct page *page, int order)
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

1222 1223 1224 1225 1226 1227 1228
/* Put bootmem huge pages into the standard lists after mem_map is up */
static void __init gather_bootmem_prealloc(void)
{
	struct huge_bootmem_page *m;

	list_for_each_entry(m, &huge_boot_pages, list) {
		struct hstate *h = m->hstate;
1229 1230 1231 1232 1233 1234 1235 1236 1237
		struct page *page;

#ifdef CONFIG_HIGHMEM
		page = pfn_to_page(m->phys >> PAGE_SHIFT);
		free_bootmem_late((unsigned long)m,
				  sizeof(struct huge_bootmem_page));
#else
		page = virt_to_page(m);
#endif
1238 1239
		__ClearPageReserved(page);
		WARN_ON(page_count(page) != 1);
1240
		prep_compound_huge_page(page, h->order);
1241
		prep_new_huge_page(h, page, page_to_nid(page));
1242 1243 1244 1245 1246 1247 1248 1249
		/*
		 * If we had gigantic hugepages allocated at boot time, we need
		 * to restore the 'stolen' pages to totalram_pages in order to
		 * fix confusing memory reports from free(1) and another
		 * side-effects, like CommitLimit going negative.
		 */
		if (h->order > (MAX_ORDER - 1))
			totalram_pages += 1 << h->order;
1250 1251 1252
	}
}

1253
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
1254 1255
{
	unsigned long i;
1256

1257
	for (i = 0; i < h->max_huge_pages; ++i) {
1258 1259 1260
		if (h->order >= MAX_ORDER) {
			if (!alloc_bootmem_huge_page(h))
				break;
1261 1262
		} else if (!alloc_fresh_huge_page(h,
					 &node_states[N_HIGH_MEMORY]))
L
Linus Torvalds 已提交
1263 1264
			break;
	}
1265
	h->max_huge_pages = i;
1266 1267 1268 1269 1270 1271 1272
}

static void __init hugetlb_init_hstates(void)
{
	struct hstate *h;

	for_each_hstate(h) {
1273 1274 1275
		/* oversize hugepages were init'ed in early boot */
		if (h->order < MAX_ORDER)
			hugetlb_hstate_alloc_pages(h);
1276 1277 1278
	}
}

A
Andi Kleen 已提交
1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289
static char * __init memfmt(char *buf, unsigned long n)
{
	if (n >= (1UL << 30))
		sprintf(buf, "%lu GB", n >> 30);
	else if (n >= (1UL << 20))
		sprintf(buf, "%lu MB", n >> 20);
	else
		sprintf(buf, "%lu KB", n >> 10);
	return buf;
}

1290 1291 1292 1293 1294
static void __init report_hugepages(void)
{
	struct hstate *h;

	for_each_hstate(h) {
A
Andi Kleen 已提交
1295 1296 1297 1298 1299
		char buf[32];
		printk(KERN_INFO "HugeTLB registered %s page size, "
				 "pre-allocated %ld pages\n",
			memfmt(buf, huge_page_size(h)),
			h->free_huge_pages);
1300 1301 1302
	}
}

L
Linus Torvalds 已提交
1303
#ifdef CONFIG_HIGHMEM
1304 1305
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
1306
{
1307 1308
	int i;

1309 1310 1311
	if (h->order >= MAX_ORDER)
		return;

1312
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
1313
		struct page *page, *next;
1314 1315 1316
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
1317
				return;
L
Linus Torvalds 已提交
1318 1319 1320
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
1321
			update_and_free_page(h, page);
1322 1323
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
1324 1325 1326 1327
		}
	}
}
#else
1328 1329
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
1330 1331 1332 1333
{
}
#endif

1334 1335 1336 1337 1338
/*
 * Increment or decrement surplus_huge_pages.  Keep node-specific counters
 * balanced by operating on them in a round-robin fashion.
 * Returns 1 if an adjustment was made.
 */
1339 1340
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
1341
{
1342
	int start_nid, next_nid;
1343 1344 1345 1346
	int ret = 0;

	VM_BUG_ON(delta != -1 && delta != 1);

1347
	if (delta < 0)
1348
		start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
1349
	else
1350
		start_nid = hstate_next_node_to_free(h, nodes_allowed);
1351 1352 1353 1354 1355 1356 1357 1358
	next_nid = start_nid;

	do {
		int nid = next_nid;
		if (delta < 0)  {
			/*
			 * To shrink on this node, there must be a surplus page
			 */
1359
			if (!h->surplus_huge_pages_node[nid]) {
1360 1361
				next_nid = hstate_next_node_to_alloc(h,
								nodes_allowed);
1362
				continue;
1363
			}
1364 1365 1366 1367 1368 1369
		}
		if (delta > 0) {
			/*
			 * Surplus cannot exceed the total number of pages
			 */
			if (h->surplus_huge_pages_node[nid] >=
1370
						h->nr_huge_pages_node[nid]) {
1371 1372
				next_nid = hstate_next_node_to_free(h,
								nodes_allowed);
1373
				continue;
1374
			}
1375
		}
1376 1377 1378 1379 1380

		h->surplus_huge_pages += delta;
		h->surplus_huge_pages_node[nid] += delta;
		ret = 1;
		break;
1381
	} while (next_nid != start_nid);
1382 1383 1384 1385

	return ret;
}

1386
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
1387 1388
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
1389
{
1390
	unsigned long min_count, ret;
L
Linus Torvalds 已提交
1391

1392 1393 1394
	if (h->order >= MAX_ORDER)
		return h->max_huge_pages;

1395 1396 1397 1398
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
1399 1400 1401 1402 1403 1404
	 *
	 * We might race with alloc_buddy_huge_page() here and be unable
	 * to convert a surplus huge page to a normal huge page. That is
	 * not critical, though, it just means the overall size of the
	 * pool might be one hugepage larger than it needs to be, but
	 * within all the constraints specified by the sysctls.
1405
	 */
L
Linus Torvalds 已提交
1406
	spin_lock(&hugetlb_lock);
1407
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
1408
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
1409 1410 1411
			break;
	}

1412
	while (count > persistent_huge_pages(h)) {
1413 1414 1415 1416 1417 1418
		/*
		 * If this allocation races such that we no longer need the
		 * page, free_huge_page will handle it by freeing the page
		 * and reducing the surplus.
		 */
		spin_unlock(&hugetlb_lock);
1419
		ret = alloc_fresh_huge_page(h, nodes_allowed);
1420 1421 1422 1423
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

1424 1425 1426
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
1427 1428 1429 1430 1431 1432 1433 1434
	}

	/*
	 * Decrease the pool size
	 * First return free pages to the buddy allocator (being careful
	 * to keep enough around to satisfy reservations).  Then place
	 * pages into surplus state as needed so the pool will shrink
	 * to the desired size as pages become free.
1435 1436 1437 1438 1439 1440 1441 1442
	 *
	 * By placing pages into the surplus state independent of the
	 * overcommit value, we are allowing the surplus pool size to
	 * exceed overcommit. There are few sane options here. Since
	 * alloc_buddy_huge_page() is checking the global counter,
	 * though, we'll note that we're not allowed to exceed surplus
	 * and won't grow the pool anywhere else. Not until one of the
	 * sysctls are changed, or the surplus pages go out of use.
1443
	 */
1444
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
1445
	min_count = max(count, min_count);
1446
	try_to_free_low(h, min_count, nodes_allowed);
1447
	while (min_count < persistent_huge_pages(h)) {
1448
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
1449 1450
			break;
	}
1451
	while (count < persistent_huge_pages(h)) {
1452
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
1453 1454 1455
			break;
	}
out:
1456
	ret = persistent_huge_pages(h);
L
Linus Torvalds 已提交
1457
	spin_unlock(&hugetlb_lock);
1458
	return ret;
L
Linus Torvalds 已提交
1459 1460
}

1461 1462 1463 1464 1465 1466 1467 1468 1469 1470
#define HSTATE_ATTR_RO(_name) \
	static struct kobj_attribute _name##_attr = __ATTR_RO(_name)

#define HSTATE_ATTR(_name) \
	static struct kobj_attribute _name##_attr = \
		__ATTR(_name, 0644, _name##_show, _name##_store)

static struct kobject *hugepages_kobj;
static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];

1471 1472 1473
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
1474 1475
{
	int i;
1476

1477
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
1478 1479 1480
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
1481
			return &hstates[i];
1482 1483 1484
		}

	return kobj_to_node_hstate(kobj, nidp);
1485 1486
}

1487
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
1488 1489
					struct kobj_attribute *attr, char *buf)
{
1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500
	struct hstate *h;
	unsigned long nr_huge_pages;
	int nid;

	h = kobj_to_hstate(kobj, &nid);
	if (nid == NUMA_NO_NODE)
		nr_huge_pages = h->nr_huge_pages;
	else
		nr_huge_pages = h->nr_huge_pages_node[nid];

	return sprintf(buf, "%lu\n", nr_huge_pages);
1501
}
1502

1503 1504 1505
static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
			struct kobject *kobj, struct kobj_attribute *attr,
			const char *buf, size_t len)
1506 1507
{
	int err;
1508
	int nid;
1509
	unsigned long count;
1510
	struct hstate *h;
1511
	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
1512

1513
	err = strict_strtoul(buf, 10, &count);
1514
	if (err)
1515
		goto out;
1516

1517
	h = kobj_to_hstate(kobj, &nid);
1518 1519 1520 1521 1522
	if (h->order >= MAX_ORDER) {
		err = -EINVAL;
		goto out;
	}

1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
				init_nodemask_of_mempolicy(nodes_allowed))) {
			NODEMASK_FREE(nodes_allowed);
			nodes_allowed = &node_states[N_HIGH_MEMORY];
		}
	} else if (nodes_allowed) {
		/*
		 * per node hstate attribute: adjust count to global,
		 * but restrict alloc/free to the specified node.
		 */
		count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
		init_nodemask_of_node(nodes_allowed, nid);
	} else
		nodes_allowed = &node_states[N_HIGH_MEMORY];

1542
	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
1543

1544
	if (nodes_allowed != &node_states[N_HIGH_MEMORY])
1545 1546 1547
		NODEMASK_FREE(nodes_allowed);

	return len;
1548 1549 1550
out:
	NODEMASK_FREE(nodes_allowed);
	return err;
1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562
}

static ssize_t nr_hugepages_show(struct kobject *kobj,
				       struct kobj_attribute *attr, char *buf)
{
	return nr_hugepages_show_common(kobj, attr, buf);
}

static ssize_t nr_hugepages_store(struct kobject *kobj,
	       struct kobj_attribute *attr, const char *buf, size_t len)
{
	return nr_hugepages_store_common(false, kobj, attr, buf, len);
1563 1564 1565
}
HSTATE_ATTR(nr_hugepages);

1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586
#ifdef CONFIG_NUMA

/*
 * hstate attribute for optionally mempolicy-based constraint on persistent
 * huge page alloc/free.
 */
static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
				       struct kobj_attribute *attr, char *buf)
{
	return nr_hugepages_show_common(kobj, attr, buf);
}

static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
	       struct kobj_attribute *attr, const char *buf, size_t len)
{
	return nr_hugepages_store_common(true, kobj, attr, buf, len);
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


1587 1588 1589
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
1590
	struct hstate *h = kobj_to_hstate(kobj, NULL);
1591 1592
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
1593

1594 1595 1596 1597 1598
static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
		struct kobj_attribute *attr, const char *buf, size_t count)
{
	int err;
	unsigned long input;
1599
	struct hstate *h = kobj_to_hstate(kobj, NULL);
1600

1601 1602 1603
	if (h->order >= MAX_ORDER)
		return -EINVAL;

1604 1605
	err = strict_strtoul(buf, 10, &input);
	if (err)
1606
		return err;
1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618

	spin_lock(&hugetlb_lock);
	h->nr_overcommit_huge_pages = input;
	spin_unlock(&hugetlb_lock);

	return count;
}
HSTATE_ATTR(nr_overcommit_hugepages);

static ssize_t free_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629
	struct hstate *h;
	unsigned long free_huge_pages;
	int nid;

	h = kobj_to_hstate(kobj, &nid);
	if (nid == NUMA_NO_NODE)
		free_huge_pages = h->free_huge_pages;
	else
		free_huge_pages = h->free_huge_pages_node[nid];

	return sprintf(buf, "%lu\n", free_huge_pages);
1630 1631 1632 1633 1634 1635
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
1636
	struct hstate *h = kobj_to_hstate(kobj, NULL);
1637 1638 1639 1640 1641 1642 1643
	return sprintf(buf, "%lu\n", h->resv_huge_pages);
}
HSTATE_ATTR_RO(resv_hugepages);

static ssize_t surplus_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
	struct hstate *h;
	unsigned long surplus_huge_pages;
	int nid;

	h = kobj_to_hstate(kobj, &nid);
	if (nid == NUMA_NO_NODE)
		surplus_huge_pages = h->surplus_huge_pages;
	else
		surplus_huge_pages = h->surplus_huge_pages_node[nid];

	return sprintf(buf, "%lu\n", surplus_huge_pages);
1655 1656 1657 1658 1659 1660 1661 1662 1663
}
HSTATE_ATTR_RO(surplus_hugepages);

static struct attribute *hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&nr_overcommit_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&resv_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
1664 1665 1666
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
1667 1668 1669 1670 1671 1672 1673
	NULL,
};

static struct attribute_group hstate_attr_group = {
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
1674 1675 1676
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
				    struct attribute_group *hstate_attr_group)
1677 1678
{
	int retval;
1679
	int hi = hstate_index(h);
1680

1681 1682
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
1683 1684
		return -ENOMEM;

1685
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
1686
	if (retval)
1687
		kobject_put(hstate_kobjs[hi]);
1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701

	return retval;
}

static void __init hugetlb_sysfs_init(void)
{
	struct hstate *h;
	int err;

	hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
	if (!hugepages_kobj)
		return;

	for_each_hstate(h) {
1702 1703
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
1704 1705 1706 1707 1708 1709
		if (err)
			printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
								h->name);
	}
}

1710 1711 1712 1713
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
1714 1715 1716
 * with node devices in node_devices[] using a parallel array.  The array
 * index of a node device or _hstate == node id.
 * This is here to avoid any static dependency of the node device driver, in
1717 1718 1719 1720 1721 1722 1723 1724 1725
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
struct node_hstate node_hstates[MAX_NUMNODES];

/*
1726
 * A subset of global hstate attributes for node devices
1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

static struct attribute_group per_node_hstate_attr_group = {
	.attrs = per_node_hstate_attrs,
};

/*
1740
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762
 * Returns node id via non-NULL nidp.
 */
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
{
	int nid;

	for (nid = 0; nid < nr_node_ids; nid++) {
		struct node_hstate *nhs = &node_hstates[nid];
		int i;
		for (i = 0; i < HUGE_MAX_HSTATE; i++)
			if (nhs->hstate_kobjs[i] == kobj) {
				if (nidp)
					*nidp = nid;
				return &hstates[i];
			}
	}

	BUG();
	return NULL;
}

/*
1763
 * Unregister hstate attributes from a single node device.
1764 1765 1766 1767 1768
 * No-op if no hstate attributes attached.
 */
void hugetlb_unregister_node(struct node *node)
{
	struct hstate *h;
1769
	struct node_hstate *nhs = &node_hstates[node->dev.id];
1770 1771

	if (!nhs->hugepages_kobj)
1772
		return;		/* no hstate attributes */
1773

1774 1775 1776 1777 1778
	for_each_hstate(h) {
		int idx = hstate_index(h);
		if (nhs->hstate_kobjs[idx]) {
			kobject_put(nhs->hstate_kobjs[idx]);
			nhs->hstate_kobjs[idx] = NULL;
1779
		}
1780
	}
1781 1782 1783 1784 1785 1786

	kobject_put(nhs->hugepages_kobj);
	nhs->hugepages_kobj = NULL;
}

/*
1787
 * hugetlb module exit:  unregister hstate attributes from node devices
1788 1789 1790 1791 1792 1793 1794
 * that have them.
 */
static void hugetlb_unregister_all_nodes(void)
{
	int nid;

	/*
1795
	 * disable node device registrations.
1796 1797 1798 1799 1800 1801 1802
	 */
	register_hugetlbfs_with_node(NULL, NULL);

	/*
	 * remove hstate attributes from any nodes that have them.
	 */
	for (nid = 0; nid < nr_node_ids; nid++)
1803
		hugetlb_unregister_node(node_devices[nid]);
1804 1805 1806
}

/*
1807
 * Register hstate attributes for a single node device.
1808 1809 1810 1811 1812
 * No-op if attributes already registered.
 */
void hugetlb_register_node(struct node *node)
{
	struct hstate *h;
1813
	struct node_hstate *nhs = &node_hstates[node->dev.id];
1814 1815 1816 1817 1818 1819
	int err;

	if (nhs->hugepages_kobj)
		return;		/* already allocated */

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
1820
							&node->dev.kobj);
1821 1822 1823 1824 1825 1826 1827 1828 1829 1830
	if (!nhs->hugepages_kobj)
		return;

	for_each_hstate(h) {
		err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
						nhs->hstate_kobjs,
						&per_node_hstate_attr_group);
		if (err) {
			printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
					" for node %d\n",
1831
						h->name, node->dev.id);
1832 1833 1834 1835 1836 1837 1838
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
1839
 * hugetlb init time:  register hstate attributes for all registered node
1840 1841
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
1842 1843 1844 1845 1846
 */
static void hugetlb_register_all_nodes(void)
{
	int nid;

1847
	for_each_node_state(nid, N_HIGH_MEMORY) {
1848
		struct node *node = node_devices[nid];
1849
		if (node->dev.id == nid)
1850 1851 1852 1853
			hugetlb_register_node(node);
	}

	/*
1854
	 * Let the node device driver know we're here so it can
1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875
	 * [un]register hstate attributes on node hotplug.
	 */
	register_hugetlbfs_with_node(hugetlb_register_node,
				     hugetlb_unregister_node);
}
#else	/* !CONFIG_NUMA */

static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
{
	BUG();
	if (nidp)
		*nidp = -1;
	return NULL;
}

static void hugetlb_unregister_all_nodes(void) { }

static void hugetlb_register_all_nodes(void) { }

#endif

1876 1877 1878 1879
static void __exit hugetlb_exit(void)
{
	struct hstate *h;

1880 1881
	hugetlb_unregister_all_nodes();

1882
	for_each_hstate(h) {
1883
		kobject_put(hstate_kobjs[hstate_index(h)]);
1884 1885 1886 1887 1888 1889 1890 1891
	}

	kobject_put(hugepages_kobj);
}
module_exit(hugetlb_exit);

static int __init hugetlb_init(void)
{
1892 1893 1894 1895 1896 1897
	/* Some platform decide whether they support huge pages at boot
	 * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
	 * there is no such support
	 */
	if (HPAGE_SHIFT == 0)
		return 0;
1898

1899 1900 1901 1902
	if (!size_to_hstate(default_hstate_size)) {
		default_hstate_size = HPAGE_SIZE;
		if (!size_to_hstate(default_hstate_size))
			hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
1903
	}
1904
	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
1905 1906
	if (default_hstate_max_huge_pages)
		default_hstate.max_huge_pages = default_hstate_max_huge_pages;
1907 1908 1909

	hugetlb_init_hstates();

1910 1911
	gather_bootmem_prealloc();

1912 1913 1914 1915
	report_hugepages();

	hugetlb_sysfs_init();

1916 1917
	hugetlb_register_all_nodes();

1918 1919 1920 1921 1922 1923 1924 1925
	return 0;
}
module_init(hugetlb_init);

/* Should be called on processing a hugepagesz=... option */
void __init hugetlb_add_hstate(unsigned order)
{
	struct hstate *h;
1926 1927
	unsigned long i;

1928 1929 1930 1931
	if (size_to_hstate(PAGE_SIZE << order)) {
		printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
		return;
	}
1932
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
1933
	BUG_ON(order == 0);
1934
	h = &hstates[hugetlb_max_hstate++];
1935 1936
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
1937 1938 1939 1940
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
1941
	INIT_LIST_HEAD(&h->hugepage_activelist);
1942 1943
	h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
	h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
1944 1945
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
1946 1947 1948 1949 1950 1951 1952
	/*
	 * Add cgroup control files only if the huge page consists
	 * of more than two normal pages. This is because we use
	 * page[2].lru.next for storing cgoup details.
	 */
	if (order >= HUGETLB_CGROUP_MIN_ORDER)
		hugetlb_cgroup_file_init(hugetlb_max_hstate - 1);
1953

1954 1955 1956
	parsed_hstate = h;
}

1957
static int __init hugetlb_nrpages_setup(char *s)
1958 1959
{
	unsigned long *mhp;
1960
	static unsigned long *last_mhp;
1961 1962

	/*
1963
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
1964 1965
	 * so this hugepages= parameter goes to the "default hstate".
	 */
1966
	if (!hugetlb_max_hstate)
1967 1968 1969 1970
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

1971 1972 1973 1974 1975 1976
	if (mhp == last_mhp) {
		printk(KERN_WARNING "hugepages= specified twice without "
			"interleaving hugepagesz=, ignoring\n");
		return 1;
	}

1977 1978 1979
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

1980 1981 1982 1983 1984
	/*
	 * Global state is always initialized later in hugetlb_init.
	 * But we need to allocate >= MAX_ORDER hstates here early to still
	 * use the bootmem allocator.
	 */
1985
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
1986 1987 1988 1989
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

1990 1991
	return 1;
}
1992 1993 1994 1995 1996 1997 1998 1999
__setup("hugepages=", hugetlb_nrpages_setup);

static int __init hugetlb_default_setup(char *s)
{
	default_hstate_size = memparse(s, &s);
	return 1;
}
__setup("default_hugepagesz=", hugetlb_default_setup);
2000

2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012
static unsigned int cpuset_mems_nr(unsigned int *array)
{
	int node;
	unsigned int nr = 0;

	for_each_node_mask(node, cpuset_current_mems_allowed)
		nr += array[node];

	return nr;
}

#ifdef CONFIG_SYSCTL
2013 2014 2015
static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
			 struct ctl_table *table, int write,
			 void __user *buffer, size_t *length, loff_t *ppos)
L
Linus Torvalds 已提交
2016
{
2017 2018
	struct hstate *h = &default_hstate;
	unsigned long tmp;
2019
	int ret;
2020

2021
	tmp = h->max_huge_pages;
2022

2023 2024 2025
	if (write && h->order >= MAX_ORDER)
		return -EINVAL;

2026 2027
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2028 2029 2030
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2031

2032
	if (write) {
2033 2034
		NODEMASK_ALLOC(nodemask_t, nodes_allowed,
						GFP_KERNEL | __GFP_NORETRY);
2035 2036 2037 2038 2039 2040 2041 2042 2043 2044
		if (!(obey_mempolicy &&
			       init_nodemask_of_mempolicy(nodes_allowed))) {
			NODEMASK_FREE(nodes_allowed);
			nodes_allowed = &node_states[N_HIGH_MEMORY];
		}
		h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);

		if (nodes_allowed != &node_states[N_HIGH_MEMORY])
			NODEMASK_FREE(nodes_allowed);
	}
2045 2046
out:
	return ret;
L
Linus Torvalds 已提交
2047
}
2048

2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
			  void __user *buffer, size_t *length, loff_t *ppos)
{

	return hugetlb_sysctl_handler_common(false, table, write,
							buffer, length, ppos);
}

#ifdef CONFIG_NUMA
int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
			  void __user *buffer, size_t *length, loff_t *ppos)
{
	return hugetlb_sysctl_handler_common(true, table, write,
							buffer, length, ppos);
}
#endif /* CONFIG_NUMA */

2066
int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
2067
			void __user *buffer,
2068 2069
			size_t *length, loff_t *ppos)
{
2070
	proc_dointvec(table, write, buffer, length, ppos);
2071 2072 2073 2074 2075 2076 2077
	if (hugepages_treat_as_movable)
		htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
	else
		htlb_alloc_mask = GFP_HIGHUSER;
	return 0;
}

2078
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2079
			void __user *buffer,
2080 2081
			size_t *length, loff_t *ppos)
{
2082
	struct hstate *h = &default_hstate;
2083
	unsigned long tmp;
2084
	int ret;
2085

2086
	tmp = h->nr_overcommit_huge_pages;
2087

2088 2089 2090
	if (write && h->order >= MAX_ORDER)
		return -EINVAL;

2091 2092
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2093 2094 2095
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2096 2097 2098 2099 2100 2101

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
2102 2103
out:
	return ret;
2104 2105
}

L
Linus Torvalds 已提交
2106 2107
#endif /* CONFIG_SYSCTL */

2108
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
2109
{
2110
	struct hstate *h = &default_hstate;
2111
	seq_printf(m,
2112 2113 2114 2115 2116
			"HugePages_Total:   %5lu\n"
			"HugePages_Free:    %5lu\n"
			"HugePages_Rsvd:    %5lu\n"
			"HugePages_Surp:    %5lu\n"
			"Hugepagesize:   %8lu kB\n",
2117 2118 2119 2120 2121
			h->nr_huge_pages,
			h->free_huge_pages,
			h->resv_huge_pages,
			h->surplus_huge_pages,
			1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
L
Linus Torvalds 已提交
2122 2123 2124 2125
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
2126
	struct hstate *h = &default_hstate;
L
Linus Torvalds 已提交
2127 2128
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
2129 2130
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
2131 2132 2133
		nid, h->nr_huge_pages_node[nid],
		nid, h->free_huge_pages_node[nid],
		nid, h->surplus_huge_pages_node[nid]);
L
Linus Torvalds 已提交
2134 2135 2136 2137 2138
}

/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
2139 2140
	struct hstate *h = &default_hstate;
	return h->nr_huge_pages * pages_per_huge_page(h);
L
Linus Torvalds 已提交
2141 2142
}

2143
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165
{
	int ret = -ENOMEM;

	spin_lock(&hugetlb_lock);
	/*
	 * When cpuset is configured, it breaks the strict hugetlb page
	 * reservation as the accounting is done on a global variable. Such
	 * reservation is completely rubbish in the presence of cpuset because
	 * the reservation is not checked against page availability for the
	 * current cpuset. Application can still potentially OOM'ed by kernel
	 * with lack of free htlb page in cpuset that the task is in.
	 * Attempt to enforce strict accounting with cpuset is almost
	 * impossible (or too ugly) because cpuset is too fluid that
	 * task or memory node can be dynamically moved between cpusets.
	 *
	 * The change of semantics for shared hugetlb mapping with cpuset is
	 * undesirable. However, in order to preserve some of the semantics,
	 * we fall back to check against current free page availability as
	 * a best attempt and hopefully to minimize the impact of changing
	 * semantics that cpuset has.
	 */
	if (delta > 0) {
2166
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
2167 2168
			goto out;

2169 2170
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
2171 2172 2173 2174 2175 2176
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
2177
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
2178 2179 2180 2181 2182 2183

out:
	spin_unlock(&hugetlb_lock);
	return ret;
}

2184 2185 2186 2187 2188 2189 2190 2191
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
	struct resv_map *reservations = vma_resv_map(vma);

	/*
	 * This new VMA should share its siblings reservation map if present.
	 * The VMA will only ever have a valid reservation map pointer where
	 * it is being copied for another still existing VMA.  As that VMA
L
Lucas De Marchi 已提交
2192
	 * has a reference to the reservation map it cannot disappear until
2193 2194 2195 2196 2197 2198 2199
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
	if (reservations)
		kref_get(&reservations->refs);
}

2200 2201 2202 2203 2204 2205 2206 2207 2208
static void resv_map_put(struct vm_area_struct *vma)
{
	struct resv_map *reservations = vma_resv_map(vma);

	if (!reservations)
		return;
	kref_put(&reservations->refs, resv_map_release);
}

2209 2210
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
2211
	struct hstate *h = hstate_vma(vma);
2212
	struct resv_map *reservations = vma_resv_map(vma);
2213
	struct hugepage_subpool *spool = subpool_vma(vma);
2214 2215 2216 2217 2218
	unsigned long reserve;
	unsigned long start;
	unsigned long end;

	if (reservations) {
2219 2220
		start = vma_hugecache_offset(h, vma, vma->vm_start);
		end = vma_hugecache_offset(h, vma, vma->vm_end);
2221 2222 2223 2224

		reserve = (end - start) -
			region_count(&reservations->regions, start, end);

2225
		resv_map_put(vma);
2226

2227
		if (reserve) {
2228
			hugetlb_acct_memory(h, -reserve);
2229
			hugepage_subpool_put_pages(spool, reserve);
2230
		}
2231
	}
2232 2233
}

L
Linus Torvalds 已提交
2234 2235 2236 2237 2238 2239
/*
 * We cannot handle pagefaults against hugetlb pages at all.  They cause
 * handle_mm_fault() to try to instantiate regular-sized pages in the
 * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
 * this far.
 */
N
Nick Piggin 已提交
2240
static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
L
Linus Torvalds 已提交
2241 2242
{
	BUG();
N
Nick Piggin 已提交
2243
	return 0;
L
Linus Torvalds 已提交
2244 2245
}

2246
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
2247
	.fault = hugetlb_vm_op_fault,
2248
	.open = hugetlb_vm_op_open,
2249
	.close = hugetlb_vm_op_close,
L
Linus Torvalds 已提交
2250 2251
};

2252 2253
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
2254 2255 2256
{
	pte_t entry;

2257
	if (writable) {
D
David Gibson 已提交
2258 2259 2260
		entry =
		    pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
	} else {
2261
		entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
D
David Gibson 已提交
2262 2263 2264
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
2265
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
2266 2267 2268 2269

	return entry;
}

2270 2271 2272 2273 2274
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

2275
	entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
2276
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
2277
		update_mmu_cache(vma, address, ptep);
2278 2279 2280
}


D
David Gibson 已提交
2281 2282 2283 2284 2285
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
			    struct vm_area_struct *vma)
{
	pte_t *src_pte, *dst_pte, entry;
	struct page *ptepage;
2286
	unsigned long addr;
2287
	int cow;
2288 2289
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
2290 2291

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
2292

2293
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
H
Hugh Dickins 已提交
2294 2295 2296
		src_pte = huge_pte_offset(src, addr);
		if (!src_pte)
			continue;
2297
		dst_pte = huge_pte_alloc(dst, addr, sz);
D
David Gibson 已提交
2298 2299
		if (!dst_pte)
			goto nomem;
2300 2301 2302 2303 2304

		/* If the pagetables are shared don't copy or take references */
		if (dst_pte == src_pte)
			continue;

H
Hugh Dickins 已提交
2305
		spin_lock(&dst->page_table_lock);
N
Nick Piggin 已提交
2306
		spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
2307
		if (!huge_pte_none(huge_ptep_get(src_pte))) {
2308
			if (cow)
2309 2310
				huge_ptep_set_wrprotect(src, addr, src_pte);
			entry = huge_ptep_get(src_pte);
2311 2312
			ptepage = pte_page(entry);
			get_page(ptepage);
2313
			page_dup_rmap(ptepage);
2314 2315 2316
			set_huge_pte_at(dst, addr, dst_pte, entry);
		}
		spin_unlock(&src->page_table_lock);
H
Hugh Dickins 已提交
2317
		spin_unlock(&dst->page_table_lock);
D
David Gibson 已提交
2318 2319 2320 2321 2322 2323 2324
	}
	return 0;

nomem:
	return -ENOMEM;
}

N
Naoya Horiguchi 已提交
2325 2326 2327 2328 2329 2330 2331
static int is_hugetlb_entry_migration(pte_t pte)
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
		return 0;
	swp = pte_to_swp_entry(pte);
2332
	if (non_swap_entry(swp) && is_migration_entry(swp))
N
Naoya Horiguchi 已提交
2333
		return 1;
2334
	else
N
Naoya Horiguchi 已提交
2335 2336 2337
		return 0;
}

2338 2339 2340 2341 2342 2343 2344
static int is_hugetlb_entry_hwpoisoned(pte_t pte)
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
		return 0;
	swp = pte_to_swp_entry(pte);
2345
	if (non_swap_entry(swp) && is_hwpoison_entry(swp))
2346
		return 1;
2347
	else
2348 2349 2350
		return 0;
}

2351 2352 2353
void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
			    unsigned long start, unsigned long end,
			    struct page *ref_page)
D
David Gibson 已提交
2354
{
2355
	int force_flush = 0;
D
David Gibson 已提交
2356 2357
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
2358
	pte_t *ptep;
D
David Gibson 已提交
2359 2360
	pte_t pte;
	struct page *page;
2361 2362
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
2363 2364
	const unsigned long mmun_start = start;	/* For mmu_notifiers */
	const unsigned long mmun_end   = end;	/* For mmu_notifiers */
2365

D
David Gibson 已提交
2366
	WARN_ON(!is_vm_hugetlb_page(vma));
2367 2368
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
2369

2370
	tlb_start_vma(tlb, vma);
2371
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2372
again:
2373
	spin_lock(&mm->page_table_lock);
2374
	for (address = start; address < end; address += sz) {
2375
		ptep = huge_pte_offset(mm, address);
A
Adam Litke 已提交
2376
		if (!ptep)
2377 2378
			continue;

2379 2380 2381
		if (huge_pmd_unshare(mm, &address, ptep))
			continue;

2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392
		pte = huge_ptep_get(ptep);
		if (huge_pte_none(pte))
			continue;

		/*
		 * HWPoisoned hugepage is already unmapped and dropped reference
		 */
		if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
			continue;

		page = pte_page(pte);
2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409
		/*
		 * If a reference page is supplied, it is because a specific
		 * page is being unmapped, not a range. Ensure the page we
		 * are about to unmap is the actual page of interest.
		 */
		if (ref_page) {
			if (page != ref_page)
				continue;

			/*
			 * Mark the VMA as having unmapped its page so that
			 * future faults in this VMA will fail rather than
			 * looking like data was lost
			 */
			set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
		}

2410
		pte = huge_ptep_get_and_clear(mm, address, ptep);
2411
		tlb_remove_tlb_entry(tlb, ptep, address);
2412 2413
		if (pte_dirty(pte))
			set_page_dirty(page);
2414

2415 2416 2417 2418
		page_remove_rmap(page);
		force_flush = !__tlb_remove_page(tlb, page);
		if (force_flush)
			break;
2419 2420 2421
		/* Bail out after unmapping reference page if supplied */
		if (ref_page)
			break;
D
David Gibson 已提交
2422
	}
2423
	spin_unlock(&mm->page_table_lock);
2424 2425 2426 2427 2428 2429 2430 2431 2432 2433
	/*
	 * mmu_gather ran out of room to batch pages, we break out of
	 * the PTE lock to avoid doing the potential expensive TLB invalidate
	 * and page-free while holding it.
	 */
	if (force_flush) {
		force_flush = 0;
		tlb_flush_mmu(tlb);
		if (address < end && !ref_page)
			goto again;
2434
	}
2435
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2436
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
2437
}
D
David Gibson 已提交
2438

2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457
void __unmap_hugepage_range_final(struct mmu_gather *tlb,
			  struct vm_area_struct *vma, unsigned long start,
			  unsigned long end, struct page *ref_page)
{
	__unmap_hugepage_range(tlb, vma, start, end, ref_page);

	/*
	 * Clear this flag so that x86's huge_pmd_share page_table_shareable
	 * test will fail on a vma being torn down, and not grab a page table
	 * on its way out.  We're lucky that the flag has such an appropriate
	 * name, and can in fact be safely cleared here. We could clear it
	 * before the __unmap_hugepage_range above, but all that's necessary
	 * is to clear it before releasing the i_mmap_mutex. This works
	 * because in the context this is called, the VMA is about to be
	 * destroyed and the i_mmap_mutex is held.
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

2458
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
2459
			  unsigned long end, struct page *ref_page)
2460
{
2461 2462 2463 2464 2465 2466 2467 2468
	struct mm_struct *mm;
	struct mmu_gather tlb;

	mm = vma->vm_mm;

	tlb_gather_mmu(&tlb, mm, 0);
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
	tlb_finish_mmu(&tlb, start, end);
2469 2470
}

2471 2472 2473 2474 2475 2476
/*
 * This is called when the original mapper is failing to COW a MAP_PRIVATE
 * mappping it owns the reserve page for. The intention is to unmap the page
 * from other VMAs and let the children be SIGKILLed if they are faulting the
 * same region.
 */
2477 2478
static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
				struct page *page, unsigned long address)
2479
{
2480
	struct hstate *h = hstate_vma(vma);
2481 2482 2483 2484 2485 2486 2487 2488
	struct vm_area_struct *iter_vma;
	struct address_space *mapping;
	pgoff_t pgoff;

	/*
	 * vm_pgoff is in PAGE_SIZE units, hence the different calculation
	 * from page cache lookup which is in HPAGE_SIZE units.
	 */
2489
	address = address & huge_page_mask(h);
2490 2491
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
2492
	mapping = vma->vm_file->f_dentry->d_inode->i_mapping;
2493

2494 2495 2496 2497 2498
	/*
	 * Take the mapping lock for the duration of the table walk. As
	 * this mapping should be shared between all the VMAs,
	 * __unmap_hugepage_range() is called as the lock is already held
	 */
2499
	mutex_lock(&mapping->i_mmap_mutex);
2500
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

		/*
		 * Unmap the page from other VMAs without their own reserves.
		 * They get marked to be SIGKILLed if they fault in these
		 * areas. This is because a future no-page fault on this VMA
		 * could insert a zeroed page instead of the data existing
		 * from the time of fork. This would look like data corruption
		 */
		if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
2513 2514
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
2515
	}
2516
	mutex_unlock(&mapping->i_mmap_mutex);
2517 2518 2519 2520

	return 1;
}

2521 2522
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
2523 2524 2525
 * Called with hugetlb_instantiation_mutex held and pte_page locked so we
 * cannot race with other handlers or page migration.
 * Keep the pte_same checks anyway to make transition from the mutex easier.
2526
 */
2527
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
2528 2529
			unsigned long address, pte_t *ptep, pte_t pte,
			struct page *pagecache_page)
2530
{
2531
	struct hstate *h = hstate_vma(vma);
2532
	struct page *old_page, *new_page;
2533
	int avoidcopy;
2534
	int outside_reserve = 0;
2535 2536
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
2537 2538 2539

	old_page = pte_page(pte);

2540
retry_avoidcopy:
2541 2542
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
2543
	avoidcopy = (page_mapcount(old_page) == 1);
2544
	if (avoidcopy) {
2545 2546
		if (PageAnon(old_page))
			page_move_anon_rmap(old_page, vma, address);
2547
		set_huge_ptep_writable(vma, address, ptep);
N
Nick Piggin 已提交
2548
		return 0;
2549 2550
	}

2551 2552 2553 2554 2555 2556 2557 2558 2559
	/*
	 * If the process that created a MAP_PRIVATE mapping is about to
	 * perform a COW due to a shared page count, attempt to satisfy
	 * the allocation without using the existing reserves. The pagecache
	 * page is used to determine if the reserve at this address was
	 * consumed or not. If reserves were used, a partial faulted mapping
	 * at the time of fork() could consume its reserves on COW instead
	 * of the full address range.
	 */
2560
	if (!(vma->vm_flags & VM_MAYSHARE) &&
2561 2562 2563 2564
			is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
			old_page != pagecache_page)
		outside_reserve = 1;

2565
	page_cache_get(old_page);
2566 2567 2568

	/* Drop page_table_lock as buddy allocator may be called */
	spin_unlock(&mm->page_table_lock);
2569
	new_page = alloc_huge_page(vma, address, outside_reserve);
2570

2571
	if (IS_ERR(new_page)) {
2572
		long err = PTR_ERR(new_page);
2573
		page_cache_release(old_page);
2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585

		/*
		 * If a process owning a MAP_PRIVATE mapping fails to COW,
		 * it is due to references held by a child and an insufficient
		 * huge page pool. To guarantee the original mappers
		 * reliability, unmap the page from child processes. The child
		 * may get SIGKILLed if it later faults.
		 */
		if (outside_reserve) {
			BUG_ON(huge_pte_none(pte));
			if (unmap_ref_private(mm, vma, old_page, address)) {
				BUG_ON(huge_pte_none(pte));
2586
				spin_lock(&mm->page_table_lock);
2587 2588 2589 2590 2591 2592 2593 2594
				ptep = huge_pte_offset(mm, address & huge_page_mask(h));
				if (likely(pte_same(huge_ptep_get(ptep), pte)))
					goto retry_avoidcopy;
				/*
				 * race occurs while re-acquiring page_table_lock, and
				 * our job is done.
				 */
				return 0;
2595 2596 2597 2598
			}
			WARN_ON_ONCE(1);
		}

2599 2600
		/* Caller expects lock to be held */
		spin_lock(&mm->page_table_lock);
2601 2602 2603 2604
		if (err == -ENOMEM)
			return VM_FAULT_OOM;
		else
			return VM_FAULT_SIGBUS;
2605 2606
	}

2607 2608 2609 2610
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
2611
	if (unlikely(anon_vma_prepare(vma))) {
2612 2613
		page_cache_release(new_page);
		page_cache_release(old_page);
2614 2615
		/* Caller expects lock to be held */
		spin_lock(&mm->page_table_lock);
2616
		return VM_FAULT_OOM;
2617
	}
2618

A
Andrea Arcangeli 已提交
2619 2620
	copy_user_huge_page(new_page, old_page, address, vma,
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
2621
	__SetPageUptodate(new_page);
2622

2623 2624 2625
	mmun_start = address & huge_page_mask(h);
	mmun_end = mmun_start + huge_page_size(h);
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2626 2627 2628 2629 2630
	/*
	 * Retake the page_table_lock to check for racing updates
	 * before the page tables are altered
	 */
	spin_lock(&mm->page_table_lock);
2631
	ptep = huge_pte_offset(mm, address & huge_page_mask(h));
2632
	if (likely(pte_same(huge_ptep_get(ptep), pte))) {
2633
		/* Break COW */
2634
		huge_ptep_clear_flush(vma, address, ptep);
2635 2636
		set_huge_pte_at(mm, address, ptep,
				make_huge_pte(vma, new_page, 1));
2637
		page_remove_rmap(old_page);
2638
		hugepage_add_new_anon_rmap(new_page, vma, address);
2639 2640 2641
		/* Make the old page be freed below */
		new_page = old_page;
	}
2642 2643 2644 2645
	spin_unlock(&mm->page_table_lock);
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
	/* Caller expects lock to be held */
	spin_lock(&mm->page_table_lock);
2646 2647
	page_cache_release(new_page);
	page_cache_release(old_page);
N
Nick Piggin 已提交
2648
	return 0;
2649 2650
}

2651
/* Return the pagecache page at a given address within a VMA */
2652 2653
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
2654 2655
{
	struct address_space *mapping;
2656
	pgoff_t idx;
2657 2658

	mapping = vma->vm_file->f_mapping;
2659
	idx = vma_hugecache_offset(h, vma, address);
2660 2661 2662 2663

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
2664 2665 2666 2667 2668
/*
 * Return whether there is a pagecache page to back given address within VMA.
 * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
 */
static bool hugetlbfs_pagecache_present(struct hstate *h,
H
Hugh Dickins 已提交
2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683
			struct vm_area_struct *vma, unsigned long address)
{
	struct address_space *mapping;
	pgoff_t idx;
	struct page *page;

	mapping = vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, vma, address);

	page = find_get_page(mapping, idx);
	if (page)
		put_page(page);
	return page != NULL;
}

2684
static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2685
			unsigned long address, pte_t *ptep, unsigned int flags)
2686
{
2687
	struct hstate *h = hstate_vma(vma);
2688
	int ret = VM_FAULT_SIGBUS;
2689
	int anon_rmap = 0;
2690
	pgoff_t idx;
A
Adam Litke 已提交
2691 2692 2693
	unsigned long size;
	struct page *page;
	struct address_space *mapping;
2694
	pte_t new_pte;
A
Adam Litke 已提交
2695

2696 2697 2698
	/*
	 * Currently, we are forced to kill the process in the event the
	 * original mapper has unmapped pages from the child due to a failed
L
Lucas De Marchi 已提交
2699
	 * COW. Warn that such a situation has occurred as it may not be obvious
2700 2701 2702 2703 2704 2705 2706 2707
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
		printk(KERN_WARNING
			"PID %d killed due to inadequate hugepage pool\n",
			current->pid);
		return ret;
	}

A
Adam Litke 已提交
2708
	mapping = vma->vm_file->f_mapping;
2709
	idx = vma_hugecache_offset(h, vma, address);
A
Adam Litke 已提交
2710 2711 2712 2713 2714

	/*
	 * Use page lock to guard against racing truncation
	 * before we get page_table_lock.
	 */
2715 2716 2717
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
2718
		size = i_size_read(mapping->host) >> huge_page_shift(h);
2719 2720
		if (idx >= size)
			goto out;
2721
		page = alloc_huge_page(vma, address, 0);
2722
		if (IS_ERR(page)) {
2723 2724 2725 2726 2727
			ret = PTR_ERR(page);
			if (ret == -ENOMEM)
				ret = VM_FAULT_OOM;
			else
				ret = VM_FAULT_SIGBUS;
2728 2729
			goto out;
		}
A
Andrea Arcangeli 已提交
2730
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
2731
		__SetPageUptodate(page);
2732

2733
		if (vma->vm_flags & VM_MAYSHARE) {
2734
			int err;
K
Ken Chen 已提交
2735
			struct inode *inode = mapping->host;
2736 2737 2738 2739 2740 2741 2742 2743

			err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
K
Ken Chen 已提交
2744 2745

			spin_lock(&inode->i_lock);
2746
			inode->i_blocks += blocks_per_huge_page(h);
K
Ken Chen 已提交
2747
			spin_unlock(&inode->i_lock);
2748
		} else {
2749
			lock_page(page);
2750 2751 2752 2753
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
2754
			anon_rmap = 1;
2755
		}
2756
	} else {
2757 2758 2759 2760 2761 2762
		/*
		 * If memory error occurs between mmap() and fault, some process
		 * don't have hwpoisoned swap entry for errored virtual address.
		 * So we need to block hugepage fault by PG_hwpoison bit check.
		 */
		if (unlikely(PageHWPoison(page))) {
2763
			ret = VM_FAULT_HWPOISON |
2764
				VM_FAULT_SET_HINDEX(hstate_index(h));
2765 2766
			goto backout_unlocked;
		}
2767
	}
2768

2769 2770 2771 2772 2773 2774
	/*
	 * If we are going to COW a private mapping later, we examine the
	 * pending reservations for this page now. This will ensure that
	 * any allocations necessary to record that reservation occur outside
	 * the spinlock.
	 */
2775
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
2776 2777 2778 2779
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
2780

2781
	spin_lock(&mm->page_table_lock);
2782
	size = i_size_read(mapping->host) >> huge_page_shift(h);
A
Adam Litke 已提交
2783 2784 2785
	if (idx >= size)
		goto backout;

N
Nick Piggin 已提交
2786
	ret = 0;
2787
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
2788 2789
		goto backout;

2790 2791 2792 2793
	if (anon_rmap)
		hugepage_add_new_anon_rmap(page, vma, address);
	else
		page_dup_rmap(page);
2794 2795 2796 2797
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
	set_huge_pte_at(mm, address, ptep, new_pte);

2798
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
2799
		/* Optimization, do the COW without a second fault */
2800
		ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
2801 2802
	}

2803
	spin_unlock(&mm->page_table_lock);
A
Adam Litke 已提交
2804 2805
	unlock_page(page);
out:
2806
	return ret;
A
Adam Litke 已提交
2807 2808 2809

backout:
	spin_unlock(&mm->page_table_lock);
2810
backout_unlocked:
A
Adam Litke 已提交
2811 2812 2813
	unlock_page(page);
	put_page(page);
	goto out;
2814 2815
}

2816
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2817
			unsigned long address, unsigned int flags)
2818 2819 2820
{
	pte_t *ptep;
	pte_t entry;
2821
	int ret;
2822
	struct page *page = NULL;
2823
	struct page *pagecache_page = NULL;
2824
	static DEFINE_MUTEX(hugetlb_instantiation_mutex);
2825
	struct hstate *h = hstate_vma(vma);
2826

2827 2828
	address &= huge_page_mask(h);

2829 2830 2831
	ptep = huge_pte_offset(mm, address);
	if (ptep) {
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
2832 2833 2834 2835
		if (unlikely(is_hugetlb_entry_migration(entry))) {
			migration_entry_wait(mm, (pmd_t *)ptep, address);
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
2836
			return VM_FAULT_HWPOISON_LARGE |
2837
				VM_FAULT_SET_HINDEX(hstate_index(h));
2838 2839
	}

2840
	ptep = huge_pte_alloc(mm, address, huge_page_size(h));
2841 2842 2843
	if (!ptep)
		return VM_FAULT_OOM;

2844 2845 2846 2847 2848 2849
	/*
	 * Serialize hugepage allocation and instantiation, so that we don't
	 * get spurious allocation failures if two CPUs race to instantiate
	 * the same page in the page cache.
	 */
	mutex_lock(&hugetlb_instantiation_mutex);
2850 2851
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
2852
		ret = hugetlb_no_page(mm, vma, address, ptep, flags);
2853
		goto out_mutex;
2854
	}
2855

N
Nick Piggin 已提交
2856
	ret = 0;
2857

2858 2859 2860 2861 2862 2863 2864 2865
	/*
	 * If we are going to COW the mapping later, we examine the pending
	 * reservations for this page now. This will ensure that any
	 * allocations necessary to record that reservation occur outside the
	 * spinlock. For private mappings, we also lookup the pagecache
	 * page now as it is used to determine if a reservation has been
	 * consumed.
	 */
2866
	if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
2867 2868
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
2869
			goto out_mutex;
2870
		}
2871

2872
		if (!(vma->vm_flags & VM_MAYSHARE))
2873 2874 2875 2876
			pagecache_page = hugetlbfs_pagecache_page(h,
								vma, address);
	}

2877 2878 2879 2880 2881 2882 2883 2884
	/*
	 * hugetlb_cow() requires page locks of pte_page(entry) and
	 * pagecache_page, so here we need take the former one
	 * when page != pagecache_page or !pagecache_page.
	 * Note that locking order is always pagecache_page -> page,
	 * so no worry about deadlock.
	 */
	page = pte_page(entry);
2885
	get_page(page);
2886
	if (page != pagecache_page)
2887 2888
		lock_page(page);

2889 2890
	spin_lock(&mm->page_table_lock);
	/* Check for a racing update before calling hugetlb_cow */
2891 2892 2893 2894
	if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
		goto out_page_table_lock;


2895
	if (flags & FAULT_FLAG_WRITE) {
2896
		if (!pte_write(entry)) {
2897 2898
			ret = hugetlb_cow(mm, vma, address, ptep, entry,
							pagecache_page);
2899 2900 2901 2902 2903
			goto out_page_table_lock;
		}
		entry = pte_mkdirty(entry);
	}
	entry = pte_mkyoung(entry);
2904 2905
	if (huge_ptep_set_access_flags(vma, address, ptep, entry,
						flags & FAULT_FLAG_WRITE))
2906
		update_mmu_cache(vma, address, ptep);
2907 2908

out_page_table_lock:
2909
	spin_unlock(&mm->page_table_lock);
2910 2911 2912 2913 2914

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
2915 2916
	if (page != pagecache_page)
		unlock_page(page);
2917
	put_page(page);
2918

2919
out_mutex:
2920
	mutex_unlock(&hugetlb_instantiation_mutex);
2921 2922

	return ret;
2923 2924
}

A
Andi Kleen 已提交
2925 2926 2927 2928 2929 2930 2931 2932 2933
/* Can be overriden by architectures */
__attribute__((weak)) struct page *
follow_huge_pud(struct mm_struct *mm, unsigned long address,
	       pud_t *pud, int write)
{
	BUG();
	return NULL;
}

D
David Gibson 已提交
2934 2935
int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
			struct page **pages, struct vm_area_struct **vmas,
2936
			unsigned long *position, int *length, int i,
H
Hugh Dickins 已提交
2937
			unsigned int flags)
D
David Gibson 已提交
2938
{
2939 2940
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
D
David Gibson 已提交
2941
	int remainder = *length;
2942
	struct hstate *h = hstate_vma(vma);
D
David Gibson 已提交
2943

2944
	spin_lock(&mm->page_table_lock);
D
David Gibson 已提交
2945
	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
2946
		pte_t *pte;
H
Hugh Dickins 已提交
2947
		int absent;
A
Adam Litke 已提交
2948
		struct page *page;
D
David Gibson 已提交
2949

A
Adam Litke 已提交
2950 2951
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
2952
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
2953 2954
		 * first, for the page indexing below to work.
		 */
2955
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
H
Hugh Dickins 已提交
2956 2957 2958 2959
		absent = !pte || huge_pte_none(huge_ptep_get(pte));

		/*
		 * When coredumping, it suits get_dump_page if we just return
H
Hugh Dickins 已提交
2960 2961 2962 2963
		 * an error where there's an empty slot with no huge pagecache
		 * to back it.  This way, we avoid allocating a hugepage, and
		 * the sparse dumpfile avoids allocating disk blocks, but its
		 * huge holes still show up with zeroes where they need to be.
H
Hugh Dickins 已提交
2964
		 */
H
Hugh Dickins 已提交
2965 2966
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
H
Hugh Dickins 已提交
2967 2968 2969
			remainder = 0;
			break;
		}
D
David Gibson 已提交
2970

H
Hugh Dickins 已提交
2971 2972
		if (absent ||
		    ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
A
Adam Litke 已提交
2973
			int ret;
D
David Gibson 已提交
2974

A
Adam Litke 已提交
2975
			spin_unlock(&mm->page_table_lock);
H
Hugh Dickins 已提交
2976 2977
			ret = hugetlb_fault(mm, vma, vaddr,
				(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
A
Adam Litke 已提交
2978
			spin_lock(&mm->page_table_lock);
2979
			if (!(ret & VM_FAULT_ERROR))
A
Adam Litke 已提交
2980
				continue;
D
David Gibson 已提交
2981

A
Adam Litke 已提交
2982 2983 2984 2985
			remainder = 0;
			break;
		}

2986
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
2987
		page = pte_page(huge_ptep_get(pte));
2988
same_page:
2989
		if (pages) {
H
Hugh Dickins 已提交
2990
			pages[i] = mem_map_offset(page, pfn_offset);
K
KOSAKI Motohiro 已提交
2991
			get_page(pages[i]);
2992
		}
D
David Gibson 已提交
2993 2994 2995 2996 2997

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
2998
		++pfn_offset;
D
David Gibson 已提交
2999 3000
		--remainder;
		++i;
3001
		if (vaddr < vma->vm_end && remainder &&
3002
				pfn_offset < pages_per_huge_page(h)) {
3003 3004 3005 3006 3007 3008
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
D
David Gibson 已提交
3009
	}
3010
	spin_unlock(&mm->page_table_lock);
D
David Gibson 已提交
3011 3012 3013
	*length = remainder;
	*position = vaddr;

H
Hugh Dickins 已提交
3014
	return i ? i : -EFAULT;
D
David Gibson 已提交
3015
}
3016 3017 3018 3019 3020 3021 3022 3023

void hugetlb_change_protection(struct vm_area_struct *vma,
		unsigned long address, unsigned long end, pgprot_t newprot)
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long start = address;
	pte_t *ptep;
	pte_t pte;
3024
	struct hstate *h = hstate_vma(vma);
3025 3026 3027 3028

	BUG_ON(address >= end);
	flush_cache_range(vma, address, end);

3029
	mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
3030
	spin_lock(&mm->page_table_lock);
3031
	for (; address < end; address += huge_page_size(h)) {
3032 3033 3034
		ptep = huge_pte_offset(mm, address);
		if (!ptep)
			continue;
3035 3036
		if (huge_pmd_unshare(mm, &address, ptep))
			continue;
3037
		if (!huge_pte_none(huge_ptep_get(ptep))) {
3038 3039 3040 3041 3042 3043
			pte = huge_ptep_get_and_clear(mm, address, ptep);
			pte = pte_mkhuge(pte_modify(pte, newprot));
			set_huge_pte_at(mm, address, ptep, pte);
		}
	}
	spin_unlock(&mm->page_table_lock);
3044 3045 3046 3047 3048 3049
	/*
	 * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
	 * may have cleared our pud entry and done put_page on the page table:
	 * once we release i_mmap_mutex, another task can do the final put_page
	 * and that page table be reused and filled with junk.
	 */
3050
	flush_tlb_range(vma, start, end);
3051
	mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
3052 3053
}

3054 3055
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
3056
					struct vm_area_struct *vma,
3057
					vm_flags_t vm_flags)
3058
{
3059
	long ret, chg;
3060
	struct hstate *h = hstate_inode(inode);
3061
	struct hugepage_subpool *spool = subpool_inode(inode);
3062

3063 3064 3065
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
3066
	 * without using reserves
3067
	 */
3068
	if (vm_flags & VM_NORESERVE)
3069 3070
		return 0;

3071 3072 3073 3074 3075 3076
	/*
	 * Shared mappings base their reservation on the number of pages that
	 * are already allocated on behalf of the file. Private mappings need
	 * to reserve the full area even if read-only as mprotect() may be
	 * called to make the mapping read-write. Assume !vma is a shm mapping
	 */
3077
	if (!vma || vma->vm_flags & VM_MAYSHARE)
3078
		chg = region_chg(&inode->i_mapping->private_list, from, to);
3079 3080 3081 3082 3083
	else {
		struct resv_map *resv_map = resv_map_alloc();
		if (!resv_map)
			return -ENOMEM;

3084
		chg = to - from;
3085

3086 3087 3088 3089
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

3090 3091 3092 3093
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
3094

3095
	/* There must be enough pages in the subpool for the mapping */
3096 3097 3098 3099
	if (hugepage_subpool_get_pages(spool, chg)) {
		ret = -ENOSPC;
		goto out_err;
	}
3100 3101

	/*
3102
	 * Check enough hugepages are available for the reservation.
3103
	 * Hand the pages back to the subpool if there are not
3104
	 */
3105
	ret = hugetlb_acct_memory(h, chg);
K
Ken Chen 已提交
3106
	if (ret < 0) {
3107
		hugepage_subpool_put_pages(spool, chg);
3108
		goto out_err;
K
Ken Chen 已提交
3109
	}
3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121

	/*
	 * Account for the reservations made. Shared mappings record regions
	 * that have reservations as they are shared by multiple VMAs.
	 * When the last VMA disappears, the region map says how much
	 * the reservation was and the page cache tells how much of
	 * the reservation was consumed. Private mappings are per-VMA and
	 * only the consumed reservations are tracked. When the VMA
	 * disappears, the original reservation is the VMA size and the
	 * consumed reservations are stored in the map. Hence, nothing
	 * else has to be done for private mappings here
	 */
3122
	if (!vma || vma->vm_flags & VM_MAYSHARE)
3123
		region_add(&inode->i_mapping->private_list, from, to);
3124
	return 0;
3125
out_err:
3126 3127
	if (vma)
		resv_map_put(vma);
3128
	return ret;
3129 3130 3131 3132
}

void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
{
3133
	struct hstate *h = hstate_inode(inode);
3134
	long chg = region_truncate(&inode->i_mapping->private_list, offset);
3135
	struct hugepage_subpool *spool = subpool_inode(inode);
K
Ken Chen 已提交
3136 3137

	spin_lock(&inode->i_lock);
3138
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
3139 3140
	spin_unlock(&inode->i_lock);

3141
	hugepage_subpool_put_pages(spool, (chg - freed));
3142
	hugetlb_acct_memory(h, -(chg - freed));
3143
}
3144

3145 3146
#ifdef CONFIG_MEMORY_FAILURE

3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160
/* Should be called in hugetlb_lock */
static int is_hugepage_on_freelist(struct page *hpage)
{
	struct page *page;
	struct page *tmp;
	struct hstate *h = page_hstate(hpage);
	int nid = page_to_nid(hpage);

	list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
		if (page == hpage)
			return 1;
	return 0;
}

3161 3162 3163 3164
/*
 * This function is called from memory failure code.
 * Assume the caller holds page lock of the head page.
 */
3165
int dequeue_hwpoisoned_huge_page(struct page *hpage)
3166 3167 3168
{
	struct hstate *h = page_hstate(hpage);
	int nid = page_to_nid(hpage);
3169
	int ret = -EBUSY;
3170 3171

	spin_lock(&hugetlb_lock);
3172 3173
	if (is_hugepage_on_freelist(hpage)) {
		list_del(&hpage->lru);
3174
		set_page_refcounted(hpage);
3175 3176 3177 3178
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		ret = 0;
	}
3179
	spin_unlock(&hugetlb_lock);
3180
	return ret;
3181
}
3182
#endif