hugetlb.c 128.4 KB
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/*
 * Generic hugetlb support.
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 * (C) Nadia Yvette Chambers, April 2004
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 */
#include <linux/list.h>
#include <linux/init.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/compiler.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/sched/signal.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 <linux/page-isolation.h>
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#include <linux/jhash.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 <linux/userfaultfd_k.h>
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#include "internal.h"
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39
int hugepages_treat_as_movable;
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41
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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/*
 * Minimum page order among possible hugepage sizes, set to a proper value
 * at boot time.
 */
static unsigned int minimum_order __read_mostly = UINT_MAX;
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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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static bool __initdata parsed_valid_hugepagesz = true;
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58
/*
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 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
 * free_huge_pages, and surplus_huge_pages.
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 */
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DEFINE_SPINLOCK(hugetlb_lock);
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/*
 * Serializes faults on the same logical page.  This is used to
 * prevent spurious OOMs when the hugepage pool is fully utilized.
 */
static int num_fault_mutexes;
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struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
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/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

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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
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	 * remain, give up any reservations mased on minimum size and
	 * free the subpool */
	if (free) {
		if (spool->min_hpages != -1)
			hugetlb_acct_memory(spool->hstate,
						-spool->min_hpages);
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		kfree(spool);
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	}
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}

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struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
						long min_hpages)
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{
	struct hugepage_subpool *spool;

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

	spin_lock_init(&spool->lock);
	spool->count = 1;
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	spool->max_hpages = max_hpages;
	spool->hstate = h;
	spool->min_hpages = min_hpages;

	if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
		kfree(spool);
		return NULL;
	}
	spool->rsv_hpages = min_hpages;
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	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);
}

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/*
 * Subpool accounting for allocating and reserving pages.
 * Return -ENOMEM if there are not enough resources to satisfy the
 * the request.  Otherwise, return the number of pages by which the
 * global pools must be adjusted (upward).  The returned value may
 * only be different than the passed value (delta) in the case where
 * a subpool minimum size must be manitained.
 */
static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
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				      long delta)
{
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	long ret = delta;
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	if (!spool)
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		return ret;
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	spin_lock(&spool->lock);
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	if (spool->max_hpages != -1) {		/* maximum size accounting */
		if ((spool->used_hpages + delta) <= spool->max_hpages)
			spool->used_hpages += delta;
		else {
			ret = -ENOMEM;
			goto unlock_ret;
		}
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	}

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	/* minimum size accounting */
	if (spool->min_hpages != -1 && spool->rsv_hpages) {
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		if (delta > spool->rsv_hpages) {
			/*
			 * Asking for more reserves than those already taken on
			 * behalf of subpool.  Return difference.
			 */
			ret = delta - spool->rsv_hpages;
			spool->rsv_hpages = 0;
		} else {
			ret = 0;	/* reserves already accounted for */
			spool->rsv_hpages -= delta;
		}
	}

unlock_ret:
	spin_unlock(&spool->lock);
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	return ret;
}

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/*
 * Subpool accounting for freeing and unreserving pages.
 * Return the number of global page reservations that must be dropped.
 * The return value may only be different than the passed value (delta)
 * in the case where a subpool minimum size must be maintained.
 */
static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
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				       long delta)
{
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	long ret = delta;

181
	if (!spool)
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		return delta;
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	spin_lock(&spool->lock);
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	if (spool->max_hpages != -1)		/* maximum size accounting */
		spool->used_hpages -= delta;

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	 /* minimum size accounting */
	if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
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		if (spool->rsv_hpages + delta <= spool->min_hpages)
			ret = 0;
		else
			ret = spool->rsv_hpages + delta - spool->min_hpages;

		spool->rsv_hpages += delta;
		if (spool->rsv_hpages > spool->min_hpages)
			spool->rsv_hpages = spool->min_hpages;
	}

	/*
	 * If hugetlbfs_put_super couldn't free spool due to an outstanding
	 * quota reference, free it now.
	 */
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	unlock_or_release_subpool(spool);
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	return ret;
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}

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)
{
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	return subpool_inode(file_inode(vma->vm_file));
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}

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/*
 * Region tracking -- allows tracking of reservations and instantiated pages
 *                    across the pages in a mapping.
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 *
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 * The region data structures are embedded into a resv_map and protected
 * by a resv_map's lock.  The set of regions within the resv_map represent
 * reservations for huge pages, or huge pages that have already been
 * instantiated within the map.  The from and to elements are huge page
 * indicies into the associated mapping.  from indicates the starting index
 * of the region.  to represents the first index past the end of  the region.
 *
 * For example, a file region structure with from == 0 and to == 4 represents
 * four huge pages in a mapping.  It is important to note that the to element
 * represents the first element past the end of the region. This is used in
 * arithmetic as 4(to) - 0(from) = 4 huge pages in the region.
 *
 * Interval notation of the form [from, to) will be used to indicate that
 * the endpoint from is inclusive and to is exclusive.
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 */
struct file_region {
	struct list_head link;
	long from;
	long to;
};

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/*
 * Add the huge page range represented by [f, t) to the reserve
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 * map.  In the normal case, existing regions will be expanded
 * to accommodate the specified range.  Sufficient regions should
 * exist for expansion due to the previous call to region_chg
 * with the same range.  However, it is possible that region_del
 * could have been called after region_chg and modifed the map
 * in such a way that no region exists to be expanded.  In this
 * case, pull a region descriptor from the cache associated with
 * the map and use that for the new range.
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 *
 * Return the number of new huge pages added to the map.  This
 * number is greater than or equal to zero.
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 */
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static long region_add(struct resv_map *resv, long f, long t)
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{
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	struct list_head *head = &resv->regions;
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	struct file_region *rg, *nrg, *trg;
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	long add = 0;
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	spin_lock(&resv->lock);
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	/* Locate the region we are either in or before. */
	list_for_each_entry(rg, head, link)
		if (f <= rg->to)
			break;

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	/*
	 * If no region exists which can be expanded to include the
	 * specified range, the list must have been modified by an
	 * interleving call to region_del().  Pull a region descriptor
	 * from the cache and use it for this range.
	 */
	if (&rg->link == head || t < rg->from) {
		VM_BUG_ON(resv->region_cache_count <= 0);

		resv->region_cache_count--;
		nrg = list_first_entry(&resv->region_cache, struct file_region,
					link);
		list_del(&nrg->link);

		nrg->from = f;
		nrg->to = t;
		list_add(&nrg->link, rg->link.prev);

		add += t - f;
		goto out_locked;
	}

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	/* 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) {
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			/* Decrement return value by the deleted range.
			 * Another range will span this area so that by
			 * end of routine add will be >= zero
			 */
			add -= (rg->to - rg->from);
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			list_del(&rg->link);
			kfree(rg);
		}
	}
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	add += (nrg->from - f);		/* Added to beginning of region */
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	nrg->from = f;
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	add += t - nrg->to;		/* Added to end of region */
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	nrg->to = t;
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out_locked:
	resv->adds_in_progress--;
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	spin_unlock(&resv->lock);
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	VM_BUG_ON(add < 0);
	return add;
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}

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/*
 * Examine the existing reserve map and determine how many
 * huge pages in the specified range [f, t) are NOT currently
 * represented.  This routine is called before a subsequent
 * call to region_add that will actually modify the reserve
 * map to add the specified range [f, t).  region_chg does
 * not change the number of huge pages represented by the
 * map.  However, if the existing regions in the map can not
 * be expanded to represent the new range, a new file_region
 * structure is added to the map as a placeholder.  This is
 * so that the subsequent region_add call will have all the
 * regions it needs and will not fail.
 *
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 * Upon entry, region_chg will also examine the cache of region descriptors
 * associated with the map.  If there are not enough descriptors cached, one
 * will be allocated for the in progress add operation.
 *
 * Returns the number of huge pages that need to be added to the existing
 * reservation map for the range [f, t).  This number is greater or equal to
 * zero.  -ENOMEM is returned if a new file_region structure or cache entry
 * is needed and can not be allocated.
354
 */
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static long region_chg(struct resv_map *resv, long f, long t)
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{
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	struct list_head *head = &resv->regions;
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	struct file_region *rg, *nrg = NULL;
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	long chg = 0;

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retry:
	spin_lock(&resv->lock);
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retry_locked:
	resv->adds_in_progress++;

	/*
	 * Check for sufficient descriptors in the cache to accommodate
	 * the number of in progress add operations.
	 */
	if (resv->adds_in_progress > resv->region_cache_count) {
		struct file_region *trg;

		VM_BUG_ON(resv->adds_in_progress - resv->region_cache_count > 1);
		/* Must drop lock to allocate a new descriptor. */
		resv->adds_in_progress--;
		spin_unlock(&resv->lock);

		trg = kmalloc(sizeof(*trg), GFP_KERNEL);
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		if (!trg) {
			kfree(nrg);
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			return -ENOMEM;
382
		}
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		spin_lock(&resv->lock);
		list_add(&trg->link, &resv->region_cache);
		resv->region_cache_count++;
		goto retry_locked;
	}

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	/* 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) {
399
		if (!nrg) {
400
			resv->adds_in_progress--;
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			spin_unlock(&resv->lock);
			nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
			if (!nrg)
				return -ENOMEM;

			nrg->from = f;
			nrg->to   = f;
			INIT_LIST_HEAD(&nrg->link);
			goto retry;
		}
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		list_add(&nrg->link, rg->link.prev);
		chg = t - f;
		goto out_nrg;
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	}

	/* 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)
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			goto out;
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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;
	}
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out:
	spin_unlock(&resv->lock);
	/*  We already know we raced and no longer need the new region */
	kfree(nrg);
	return chg;
out_nrg:
	spin_unlock(&resv->lock);
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	return chg;
}

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/*
 * Abort the in progress add operation.  The adds_in_progress field
 * of the resv_map keeps track of the operations in progress between
 * calls to region_chg and region_add.  Operations are sometimes
 * aborted after the call to region_chg.  In such cases, region_abort
 * is called to decrement the adds_in_progress counter.
 *
 * NOTE: The range arguments [f, t) are not needed or used in this
 * routine.  They are kept to make reading the calling code easier as
 * arguments will match the associated region_chg call.
 */
static void region_abort(struct resv_map *resv, long f, long t)
{
	spin_lock(&resv->lock);
	VM_BUG_ON(!resv->region_cache_count);
	resv->adds_in_progress--;
	spin_unlock(&resv->lock);
}

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/*
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 * Delete the specified range [f, t) from the reserve map.  If the
 * t parameter is LONG_MAX, this indicates that ALL regions after f
 * should be deleted.  Locate the regions which intersect [f, t)
 * and either trim, delete or split the existing regions.
 *
 * Returns the number of huge pages deleted from the reserve map.
 * In the normal case, the return value is zero or more.  In the
 * case where a region must be split, a new region descriptor must
 * be allocated.  If the allocation fails, -ENOMEM will be returned.
 * NOTE: If the parameter t == LONG_MAX, then we will never split
 * a region and possibly return -ENOMEM.  Callers specifying
 * t == LONG_MAX do not need to check for -ENOMEM error.
481
 */
482
static long region_del(struct resv_map *resv, long f, long t)
483
{
484
	struct list_head *head = &resv->regions;
485
	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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retry:
490
	spin_lock(&resv->lock);
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	list_for_each_entry_safe(rg, trg, head, link) {
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		/*
		 * Skip regions before the range to be deleted.  file_region
		 * ranges are normally of the form [from, to).  However, there
		 * may be a "placeholder" entry in the map which is of the form
		 * (from, to) with from == to.  Check for placeholder entries
		 * at the beginning of the range to be deleted.
		 */
		if (rg->to <= f && (rg->to != rg->from || rg->to != f))
500
			continue;
501

502
		if (rg->from >= t)
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			break;

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		if (f > rg->from && t < rg->to) { /* Must split region */
			/*
			 * Check for an entry in the cache before dropping
			 * lock and attempting allocation.
			 */
			if (!nrg &&
			    resv->region_cache_count > resv->adds_in_progress) {
				nrg = list_first_entry(&resv->region_cache,
							struct file_region,
							link);
				list_del(&nrg->link);
				resv->region_cache_count--;
			}
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			if (!nrg) {
				spin_unlock(&resv->lock);
				nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
				if (!nrg)
					return -ENOMEM;
				goto retry;
			}

			del += t - f;

			/* New entry for end of split region */
			nrg->from = t;
			nrg->to = rg->to;
			INIT_LIST_HEAD(&nrg->link);

			/* Original entry is trimmed */
			rg->to = f;

			list_add(&nrg->link, &rg->link);
			nrg = NULL;
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			break;
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		}

		if (f <= rg->from && t >= rg->to) { /* Remove entire region */
			del += rg->to - rg->from;
			list_del(&rg->link);
			kfree(rg);
			continue;
		}

		if (f <= rg->from) {	/* Trim beginning of region */
			del += t - rg->from;
			rg->from = t;
		} else {		/* Trim end of region */
			del += rg->to - f;
			rg->to = f;
		}
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	}
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	spin_unlock(&resv->lock);
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	kfree(nrg);
	return del;
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}

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/*
 * A rare out of memory error was encountered which prevented removal of
 * the reserve map region for a page.  The huge page itself was free'ed
 * and removed from the page cache.  This routine will adjust the subpool
 * usage count, and the global reserve count if needed.  By incrementing
 * these counts, the reserve map entry which could not be deleted will
 * appear as a "reserved" entry instead of simply dangling with incorrect
 * counts.
 */
572
void hugetlb_fix_reserve_counts(struct inode *inode)
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{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;

	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
578
	if (rsv_adjust) {
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		struct hstate *h = hstate_inode(inode);

		hugetlb_acct_memory(h, 1);
	}
}

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/*
 * Count and return the number of huge pages in the reserve map
 * that intersect with the range [f, t).
 */
589
static long region_count(struct resv_map *resv, long f, long t)
590
{
591
	struct list_head *head = &resv->regions;
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	struct file_region *rg;
	long chg = 0;

595
	spin_lock(&resv->lock);
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	/* 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;
	}
611
	spin_unlock(&resv->lock);
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	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)
622
{
623 624
	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
625 626
}

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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);
}
632
EXPORT_SYMBOL_GPL(linear_hugepage_index);
633

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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);

647
	return 1UL << huge_page_shift(hstate);
648
}
649
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
650

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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

664 665 666 667 668 669 670
/*
 * 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)
671
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
672

673 674 675 676 677 678 679 680 681
/*
 * 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.
682 683 684 685 686 687 688 689 690
 *
 * 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.
691
 */
692 693 694 695 696 697 698 699 700 701 702
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;
}

703
struct resv_map *resv_map_alloc(void)
704 705
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
706 707 708 709 710
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
711
		return NULL;
712
	}
713 714

	kref_init(&resv_map->refs);
715
	spin_lock_init(&resv_map->lock);
716 717
	INIT_LIST_HEAD(&resv_map->regions);

718 719 720 721 722 723
	resv_map->adds_in_progress = 0;

	INIT_LIST_HEAD(&resv_map->region_cache);
	list_add(&rg->link, &resv_map->region_cache);
	resv_map->region_cache_count = 1;

724 725 726
	return resv_map;
}

727
void resv_map_release(struct kref *ref)
728 729
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
730 731
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
732 733

	/* Clear out any active regions before we release the map. */
734
	region_del(resv_map, 0, LONG_MAX);
735 736 737 738 739 740 741 742 743

	/* ... and any entries left in the cache */
	list_for_each_entry_safe(rg, trg, head, link) {
		list_del(&rg->link);
		kfree(rg);
	}

	VM_BUG_ON(resv_map->adds_in_progress);

744 745 746
	kfree(resv_map);
}

747 748 749 750 751
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
	return inode->i_mapping->private_data;
}

752
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
753
{
754
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
755 756 757 758 759 760 761
	if (vma->vm_flags & VM_MAYSHARE) {
		struct address_space *mapping = vma->vm_file->f_mapping;
		struct inode *inode = mapping->host;

		return inode_resv_map(inode);

	} else {
762 763
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
764
	}
765 766
}

767
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
768
{
769 770
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
771

772 773
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
774 775 776 777
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
778 779
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
780 781

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
782 783 784 785
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
786
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
787 788

	return (get_vma_private_data(vma) & flag) != 0;
789 790
}

791
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
792 793
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
794
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
795
	if (!(vma->vm_flags & VM_MAYSHARE))
796 797 798 799
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
800
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
801
{
802 803 804 805 806 807 808 809 810 811 812
	if (vma->vm_flags & VM_NORESERVE) {
		/*
		 * This address is already reserved by other process(chg == 0),
		 * so, we should decrement reserved count. Without decrementing,
		 * reserve count remains after releasing inode, because this
		 * allocated page will go into page cache and is regarded as
		 * coming from reserved pool in releasing step.  Currently, we
		 * don't have any other solution to deal with this situation
		 * properly, so add work-around here.
		 */
		if (vma->vm_flags & VM_MAYSHARE && chg == 0)
813
			return true;
814
		else
815
			return false;
816
	}
817 818

	/* Shared mappings always use reserves */
819 820 821 822 823 824 825 826 827 828 829 830 831
	if (vma->vm_flags & VM_MAYSHARE) {
		/*
		 * We know VM_NORESERVE is not set.  Therefore, there SHOULD
		 * be a region map for all pages.  The only situation where
		 * there is no region map is if a hole was punched via
		 * fallocate.  In this case, there really are no reverves to
		 * use.  This situation is indicated if chg != 0.
		 */
		if (chg)
			return false;
		else
			return true;
	}
832 833 834 835 836

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
		/*
		 * Like the shared case above, a hole punch or truncate
		 * could have been performed on the private mapping.
		 * Examine the value of chg to determine if reserves
		 * actually exist or were previously consumed.
		 * Very Subtle - The value of chg comes from a previous
		 * call to vma_needs_reserves().  The reserve map for
		 * private mappings has different (opposite) semantics
		 * than that of shared mappings.  vma_needs_reserves()
		 * has already taken this difference in semantics into
		 * account.  Therefore, the meaning of chg is the same
		 * as in the shared case above.  Code could easily be
		 * combined, but keeping it separate draws attention to
		 * subtle differences.
		 */
		if (chg)
			return false;
		else
			return true;
	}
858

859
	return false;
860 861
}

862
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
863 864
{
	int nid = page_to_nid(page);
865
	list_move(&page->lru, &h->hugepage_freelists[nid]);
866 867
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
868 869
}

870
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
871 872 873
{
	struct page *page;

874 875 876 877 878 879 880 881
	list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
		if (!is_migrate_isolate_page(page))
			break;
	/*
	 * if 'non-isolated free hugepage' not found on the list,
	 * the allocation fails.
	 */
	if (&h->hugepage_freelists[nid] == &page->lru)
882
		return NULL;
883
	list_move(&page->lru, &h->hugepage_activelist);
884
	set_page_refcounted(page);
885 886 887 888 889
	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905
static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
{
	struct page *page;
	int node;

	if (nid != NUMA_NO_NODE)
		return dequeue_huge_page_node_exact(h, nid);

	for_each_online_node(node) {
		page = dequeue_huge_page_node_exact(h, node);
		if (page)
			return page;
	}
	return NULL;
}

906 907 908
/* Movability of hugepages depends on migration support. */
static inline gfp_t htlb_alloc_mask(struct hstate *h)
{
909
	if (hugepages_treat_as_movable || hugepage_migration_supported(h))
910 911 912 913 914
		return GFP_HIGHUSER_MOVABLE;
	else
		return GFP_HIGHUSER;
}

915 916
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
917 918
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
919
{
920
	struct page *page = NULL;
921
	struct mempolicy *mpol;
922
	nodemask_t *nodemask;
923
	struct zonelist *zonelist;
924 925
	struct zone *zone;
	struct zoneref *z;
926
	unsigned int cpuset_mems_cookie;
L
Linus Torvalds 已提交
927

928 929 930 931 932
	/*
	 * 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
	 */
933
	if (!vma_has_reserves(vma, chg) &&
934
			h->free_huge_pages - h->resv_huge_pages == 0)
935
		goto err;
936

937
	/* If reserves cannot be used, ensure enough pages are in the pool */
938
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
939
		goto err;
940

941
retry_cpuset:
942
	cpuset_mems_cookie = read_mems_allowed_begin();
943
	zonelist = huge_zonelist(vma, address,
944
					htlb_alloc_mask(h), &mpol, &nodemask);
945

946 947
	for_each_zone_zonelist_nodemask(zone, z, zonelist,
						MAX_NR_ZONES - 1, nodemask) {
948
		if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
949 950
			page = dequeue_huge_page_node(h, zone_to_nid(zone));
			if (page) {
951 952 953 954 955
				if (avoid_reserve)
					break;
				if (!vma_has_reserves(vma, chg))
					break;

956
				SetPagePrivate(page);
957
				h->resv_huge_pages--;
958 959
				break;
			}
A
Andrew Morton 已提交
960
		}
L
Linus Torvalds 已提交
961
	}
962

963
	mpol_cond_put(mpol);
964
	if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
965
		goto retry_cpuset;
L
Linus Torvalds 已提交
966
	return page;
967 968 969

err:
	return NULL;
L
Linus Torvalds 已提交
970 971
}

972 973 974 975 976 977 978 979 980
/*
 * 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.
 */
static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
{
981
	nid = next_node_in(nid, *nodes_allowed);
982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042
	VM_BUG_ON(nid >= MAX_NUMNODES);

	return nid;
}

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;
}

/*
 * 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.
 */
static int hstate_next_node_to_alloc(struct hstate *h,
					nodemask_t *nodes_allowed)
{
	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);

	return nid;
}

/*
 * 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.
 */
static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
{
	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);

	return nid;
}

#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask)		\
	for (nr_nodes = nodes_weight(*mask);				\
		nr_nodes > 0 &&						\
		((node = hstate_next_node_to_alloc(hs, mask)) || 1);	\
		nr_nodes--)

#define for_each_node_mask_to_free(hs, nr_nodes, node, mask)		\
	for (nr_nodes = nodes_weight(*mask);				\
		nr_nodes > 0 &&						\
		((node = hstate_next_node_to_free(hs, mask)) || 1);	\
		nr_nodes--)

1043
#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && \
1044 1045
	((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || \
	defined(CONFIG_CMA))
1046
static void destroy_compound_gigantic_page(struct page *page,
1047
					unsigned int order)
1048 1049 1050 1051 1052
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1053
	atomic_set(compound_mapcount_ptr(page), 0);
1054
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1055
		clear_compound_head(p);
1056 1057 1058 1059 1060 1061 1062
		set_page_refcounted(p);
	}

	set_compound_order(page, 0);
	__ClearPageHead(page);
}

1063
static void free_gigantic_page(struct page *page, unsigned int order)
1064 1065 1066 1067 1068 1069 1070 1071
{
	free_contig_range(page_to_pfn(page), 1 << order);
}

static int __alloc_gigantic_page(unsigned long start_pfn,
				unsigned long nr_pages)
{
	unsigned long end_pfn = start_pfn + nr_pages;
1072 1073
	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
				  GFP_KERNEL);
1074 1075
}

1076 1077
static bool pfn_range_valid_gigantic(struct zone *z,
			unsigned long start_pfn, unsigned long nr_pages)
1078 1079 1080 1081 1082 1083 1084 1085 1086 1087
{
	unsigned long i, end_pfn = start_pfn + nr_pages;
	struct page *page;

	for (i = start_pfn; i < end_pfn; i++) {
		if (!pfn_valid(i))
			return false;

		page = pfn_to_page(i);

1088 1089 1090
		if (page_zone(page) != z)
			return false;

1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110
		if (PageReserved(page))
			return false;

		if (page_count(page) > 0)
			return false;

		if (PageHuge(page))
			return false;
	}

	return true;
}

static bool zone_spans_last_pfn(const struct zone *zone,
			unsigned long start_pfn, unsigned long nr_pages)
{
	unsigned long last_pfn = start_pfn + nr_pages - 1;
	return zone_spans_pfn(zone, last_pfn);
}

1111
static struct page *alloc_gigantic_page(int nid, unsigned int order)
1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122
{
	unsigned long nr_pages = 1 << order;
	unsigned long ret, pfn, flags;
	struct zone *z;

	z = NODE_DATA(nid)->node_zones;
	for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) {
		spin_lock_irqsave(&z->lock, flags);

		pfn = ALIGN(z->zone_start_pfn, nr_pages);
		while (zone_spans_last_pfn(z, pfn, nr_pages)) {
1123
			if (pfn_range_valid_gigantic(z, pfn, nr_pages)) {
1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146
				/*
				 * We release the zone lock here because
				 * alloc_contig_range() will also lock the zone
				 * at some point. If there's an allocation
				 * spinning on this lock, it may win the race
				 * and cause alloc_contig_range() to fail...
				 */
				spin_unlock_irqrestore(&z->lock, flags);
				ret = __alloc_gigantic_page(pfn, nr_pages);
				if (!ret)
					return pfn_to_page(pfn);
				spin_lock_irqsave(&z->lock, flags);
			}
			pfn += nr_pages;
		}

		spin_unlock_irqrestore(&z->lock, flags);
	}

	return NULL;
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1147
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179

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

	page = alloc_gigantic_page(nid, huge_page_order(h));
	if (page) {
		prep_compound_gigantic_page(page, huge_page_order(h));
		prep_new_huge_page(h, page, nid);
	}

	return page;
}

static int alloc_fresh_gigantic_page(struct hstate *h,
				nodemask_t *nodes_allowed)
{
	struct page *page = NULL;
	int nr_nodes, node;

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
		page = alloc_fresh_gigantic_page_node(h, node);
		if (page)
			return 1;
	}

	return 0;
}

static inline bool gigantic_page_supported(void) { return true; }
#else
static inline bool gigantic_page_supported(void) { return false; }
1180
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1181
static inline void destroy_compound_gigantic_page(struct page *page,
1182
						unsigned int order) { }
1183 1184 1185 1186
static inline int alloc_fresh_gigantic_page(struct hstate *h,
					nodemask_t *nodes_allowed) { return 0; }
#endif

1187
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1188 1189
{
	int i;
1190

1191 1192
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
		return;
1193

1194 1195 1196
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1197 1198
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1199 1200
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1201
	}
1202
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1203
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1204
	set_page_refcounted(page);
1205 1206 1207 1208 1209 1210
	if (hstate_is_gigantic(h)) {
		destroy_compound_gigantic_page(page, huge_page_order(h));
		free_gigantic_page(page, huge_page_order(h));
	} else {
		__free_pages(page, huge_page_order(h));
	}
A
Adam Litke 已提交
1211 1212
}

1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223
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;
}

1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
/*
 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
 * to hstate->hugepage_activelist.)
 *
 * This function can be called for tail pages, but never returns true for them.
 */
bool page_huge_active(struct page *page)
{
	VM_BUG_ON_PAGE(!PageHuge(page), page);
	return PageHead(page) && PagePrivate(&page[1]);
}

/* never called for tail page */
static void set_page_huge_active(struct page *page)
{
	VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
	SetPagePrivate(&page[1]);
}

static void clear_page_huge_active(struct page *page)
{
	VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
	ClearPagePrivate(&page[1]);
}

1249
void free_huge_page(struct page *page)
1250
{
1251 1252 1253 1254
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1255
	struct hstate *h = page_hstate(page);
1256
	int nid = page_to_nid(page);
1257 1258
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1259
	bool restore_reserve;
1260

1261
	set_page_private(page, 0);
1262
	page->mapping = NULL;
1263 1264
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1265
	restore_reserve = PagePrivate(page);
1266
	ClearPagePrivate(page);
1267

1268 1269 1270 1271 1272 1273 1274 1275
	/*
	 * A return code of zero implies that the subpool will be under its
	 * minimum size if the reservation is not restored after page is free.
	 * Therefore, force restore_reserve operation.
	 */
	if (hugepage_subpool_put_pages(spool, 1) == 0)
		restore_reserve = true;

1276
	spin_lock(&hugetlb_lock);
1277
	clear_page_huge_active(page);
1278 1279
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1280 1281 1282
	if (restore_reserve)
		h->resv_huge_pages++;

1283
	if (h->surplus_huge_pages_node[nid]) {
1284 1285
		/* remove the page from active list */
		list_del(&page->lru);
1286 1287 1288
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1289
	} else {
1290
		arch_clear_hugepage_flags(page);
1291
		enqueue_huge_page(h, page);
1292
	}
1293 1294 1295
	spin_unlock(&hugetlb_lock);
}

1296
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1297
{
1298
	INIT_LIST_HEAD(&page->lru);
1299
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1300
	spin_lock(&hugetlb_lock);
1301
	set_hugetlb_cgroup(page, NULL);
1302 1303
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1304 1305 1306 1307
	spin_unlock(&hugetlb_lock);
	put_page(page); /* free it into the hugepage allocator */
}

1308
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1309 1310 1311 1312 1313 1314 1315
{
	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);
1316
	__ClearPageReserved(page);
1317
	__SetPageHead(page);
1318
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331
		/*
		 * For gigantic hugepages allocated through bootmem at
		 * boot, it's safer to be consistent with the not-gigantic
		 * hugepages and clear the PG_reserved bit from all tail pages
		 * too.  Otherwse drivers using get_user_pages() to access tail
		 * pages may get the reference counting wrong if they see
		 * PG_reserved set on a tail page (despite the head page not
		 * having PG_reserved set).  Enforcing this consistency between
		 * head and tail pages allows drivers to optimize away a check
		 * on the head page when they need know if put_page() is needed
		 * after get_user_pages().
		 */
		__ClearPageReserved(p);
1332
		set_page_count(p, 0);
1333
		set_compound_head(p, page);
1334
	}
1335
	atomic_set(compound_mapcount_ptr(page), -1);
1336 1337
}

A
Andrew Morton 已提交
1338 1339 1340 1341 1342
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1343 1344 1345 1346 1347 1348
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1349
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1350
}
1351 1352
EXPORT_SYMBOL_GPL(PageHuge);

1353 1354 1355 1356 1357 1358 1359 1360 1361
/*
 * PageHeadHuge() only returns true for hugetlbfs head page, but not for
 * normal or transparent huge pages.
 */
int PageHeadHuge(struct page *page_head)
{
	if (!PageHead(page_head))
		return 0;

1362
	return get_compound_page_dtor(page_head) == free_huge_page;
1363 1364
}

1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
pgoff_t __basepage_index(struct page *page)
{
	struct page *page_head = compound_head(page);
	pgoff_t index = page_index(page_head);
	unsigned long compound_idx;

	if (!PageHuge(page_head))
		return page_index(page);

	if (compound_order(page_head) >= MAX_ORDER)
		compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
	else
		compound_idx = page - page_head;

	return (index << compound_order(page_head)) + compound_idx;
}

1382
static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
L
Linus Torvalds 已提交
1383 1384
{
	struct page *page;
1385

1386
	page = __alloc_pages_node(nid,
1387
		htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1388
						__GFP_REPEAT|__GFP_NOWARN,
1389
		huge_page_order(h));
L
Linus Torvalds 已提交
1390
	if (page) {
1391
		prep_new_huge_page(h, page, nid);
L
Linus Torvalds 已提交
1392
	}
1393 1394 1395 1396

	return page;
}

1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
{
	struct page *page;
	int nr_nodes, node;
	int ret = 0;

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
		page = alloc_fresh_huge_page_node(h, node);
		if (page) {
			ret = 1;
			break;
		}
	}

	if (ret)
		count_vm_event(HTLB_BUDDY_PGALLOC);
	else
		count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);

	return ret;
}

1419 1420 1421 1422 1423 1424
/*
 * 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.
 */
1425 1426
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1427
{
1428
	int nr_nodes, node;
1429 1430
	int ret = 0;

1431
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1432 1433 1434 1435
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1436 1437
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1438
			struct page *page =
1439
				list_entry(h->hugepage_freelists[node].next,
1440 1441 1442
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1443
			h->free_huge_pages_node[node]--;
1444 1445
			if (acct_surplus) {
				h->surplus_huge_pages--;
1446
				h->surplus_huge_pages_node[node]--;
1447
			}
1448 1449
			update_and_free_page(h, page);
			ret = 1;
1450
			break;
1451
		}
1452
	}
1453 1454 1455 1456

	return ret;
}

1457 1458
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1459 1460 1461
 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
 * number of free hugepages would be reduced below the number of reserved
 * hugepages.
1462
 */
1463
static int dissolve_free_huge_page(struct page *page)
1464
{
1465 1466
	int rc = 0;

1467 1468
	spin_lock(&hugetlb_lock);
	if (PageHuge(page) && !page_count(page)) {
1469 1470 1471
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1472 1473 1474 1475
		if (h->free_huge_pages - h->resv_huge_pages == 0) {
			rc = -EBUSY;
			goto out;
		}
1476
		list_del(&head->lru);
1477 1478
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1479
		h->max_huge_pages--;
1480
		update_and_free_page(h, head);
1481
	}
1482
out:
1483
	spin_unlock(&hugetlb_lock);
1484
	return rc;
1485 1486 1487 1488 1489
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1490 1491
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1492 1493
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1494
 */
1495
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1496 1497
{
	unsigned long pfn;
1498
	struct page *page;
1499
	int rc = 0;
1500

1501
	if (!hugepages_supported())
1502
		return rc;
1503

1504 1505 1506 1507 1508 1509 1510 1511
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
		if (PageHuge(page) && !page_count(page)) {
			rc = dissolve_free_huge_page(page);
			if (rc)
				break;
		}
	}
1512 1513

	return rc;
1514 1515
}

1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533
/*
 * There are 3 ways this can get called:
 * 1. With vma+addr: we use the VMA's memory policy
 * 2. With !vma, but nid=NUMA_NO_NODE:  We try to allocate a huge
 *    page from any node, and let the buddy allocator itself figure
 *    it out.
 * 3. With !vma, but nid!=NUMA_NO_NODE.  We allocate a huge page
 *    strictly from 'nid'
 */
static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h,
		struct vm_area_struct *vma, unsigned long addr, int nid)
{
	int order = huge_page_order(h);
	gfp_t gfp = htlb_alloc_mask(h)|__GFP_COMP|__GFP_REPEAT|__GFP_NOWARN;
	unsigned int cpuset_mems_cookie;

	/*
	 * We need a VMA to get a memory policy.  If we do not
D
Dave Hansen 已提交
1534 1535 1536 1537 1538 1539
	 * have one, we use the 'nid' argument.
	 *
	 * The mempolicy stuff below has some non-inlined bits
	 * and calls ->vm_ops.  That makes it hard to optimize at
	 * compile-time, even when NUMA is off and it does
	 * nothing.  This helps the compiler optimize it out.
1540
	 */
D
Dave Hansen 已提交
1541
	if (!IS_ENABLED(CONFIG_NUMA) || !vma) {
1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557
		/*
		 * If a specific node is requested, make sure to
		 * get memory from there, but only when a node
		 * is explicitly specified.
		 */
		if (nid != NUMA_NO_NODE)
			gfp |= __GFP_THISNODE;
		/*
		 * Make sure to call something that can handle
		 * nid=NUMA_NO_NODE
		 */
		return alloc_pages_node(nid, gfp, order);
	}

	/*
	 * OK, so we have a VMA.  Fetch the mempolicy and try to
D
Dave Hansen 已提交
1558 1559
	 * allocate a huge page with it.  We will only reach this
	 * when CONFIG_NUMA=y.
1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591
	 */
	do {
		struct page *page;
		struct mempolicy *mpol;
		struct zonelist *zl;
		nodemask_t *nodemask;

		cpuset_mems_cookie = read_mems_allowed_begin();
		zl = huge_zonelist(vma, addr, gfp, &mpol, &nodemask);
		mpol_cond_put(mpol);
		page = __alloc_pages_nodemask(gfp, order, zl, nodemask);
		if (page)
			return page;
	} while (read_mems_allowed_retry(cpuset_mems_cookie));

	return NULL;
}

/*
 * There are two ways to allocate a huge page:
 * 1. When you have a VMA and an address (like a fault)
 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
 *
 * 'vma' and 'addr' are only for (1).  'nid' is always NUMA_NO_NODE in
 * this case which signifies that the allocation should be done with
 * respect for the VMA's memory policy.
 *
 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
 * implies that memory policies will not be taken in to account.
 */
static struct page *__alloc_buddy_huge_page(struct hstate *h,
		struct vm_area_struct *vma, unsigned long addr, int nid)
1592 1593
{
	struct page *page;
1594
	unsigned int r_nid;
1595

1596
	if (hstate_is_gigantic(h))
1597 1598
		return NULL;

1599 1600 1601 1602 1603 1604
	/*
	 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
	 * This makes sure the caller is picking _one_ of the modes with which
	 * we can call this function, not both.
	 */
	if (vma || (addr != -1)) {
D
Dave Hansen 已提交
1605 1606
		VM_WARN_ON_ONCE(addr == -1);
		VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
1607
	}
1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631
	/*
	 * 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);
1632
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1633 1634 1635
		spin_unlock(&hugetlb_lock);
		return NULL;
	} else {
1636 1637
		h->nr_huge_pages++;
		h->surplus_huge_pages++;
1638 1639 1640
	}
	spin_unlock(&hugetlb_lock);

1641
	page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid);
1642 1643

	spin_lock(&hugetlb_lock);
1644
	if (page) {
1645
		INIT_LIST_HEAD(&page->lru);
1646
		r_nid = page_to_nid(page);
1647
		set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1648
		set_hugetlb_cgroup(page, NULL);
1649 1650 1651
		/*
		 * We incremented the global counters already
		 */
1652 1653
		h->nr_huge_pages_node[r_nid]++;
		h->surplus_huge_pages_node[r_nid]++;
1654
		__count_vm_event(HTLB_BUDDY_PGALLOC);
1655
	} else {
1656 1657
		h->nr_huge_pages--;
		h->surplus_huge_pages--;
1658
		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1659
	}
1660
	spin_unlock(&hugetlb_lock);
1661 1662 1663 1664

	return page;
}

1665 1666 1667 1668 1669
/*
 * Allocate a huge page from 'nid'.  Note, 'nid' may be
 * NUMA_NO_NODE, which means that it may be allocated
 * anywhere.
 */
D
Dave Hansen 已提交
1670
static
1671 1672 1673 1674 1675 1676 1677 1678 1679 1680
struct page *__alloc_buddy_huge_page_no_mpol(struct hstate *h, int nid)
{
	unsigned long addr = -1;

	return __alloc_buddy_huge_page(h, NULL, addr, nid);
}

/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1681
static
1682 1683 1684 1685 1686 1687
struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
		struct vm_area_struct *vma, unsigned long addr)
{
	return __alloc_buddy_huge_page(h, vma, addr, NUMA_NO_NODE);
}

1688 1689 1690 1691 1692 1693 1694
/*
 * 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)
{
1695
	struct page *page = NULL;
1696 1697

	spin_lock(&hugetlb_lock);
1698 1699
	if (h->free_huge_pages - h->resv_huge_pages > 0)
		page = dequeue_huge_page_node(h, nid);
1700 1701
	spin_unlock(&hugetlb_lock);

1702
	if (!page)
1703
		page = __alloc_buddy_huge_page_no_mpol(h, nid);
1704 1705 1706 1707

	return page;
}

1708
/*
L
Lucas De Marchi 已提交
1709
 * Increase the hugetlb pool such that it can accommodate a reservation
1710 1711
 * of size 'delta'.
 */
1712
static int gather_surplus_pages(struct hstate *h, int delta)
1713 1714 1715 1716 1717
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
1718
	bool alloc_ok = true;
1719

1720
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1721
	if (needed <= 0) {
1722
		h->resv_huge_pages += delta;
1723
		return 0;
1724
	}
1725 1726 1727 1728 1729 1730 1731 1732

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
1733
		page = __alloc_buddy_huge_page_no_mpol(h, NUMA_NO_NODE);
1734 1735 1736 1737
		if (!page) {
			alloc_ok = false;
			break;
		}
1738 1739
		list_add(&page->lru, &surplus_list);
	}
1740
	allocated += i;
1741 1742 1743 1744 1745 1746

	/*
	 * 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);
1747 1748
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
1749 1750 1751 1752 1753 1754 1755 1756 1757 1758
	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;
	}
1759 1760
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
1761
	 * needed to accommodate the reservation.  Add the appropriate number
1762
	 * of pages to the hugetlb pool and free the extras back to the buddy
1763 1764 1765
	 * 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.
1766 1767
	 */
	needed += allocated;
1768
	h->resv_huge_pages += delta;
1769
	ret = 0;
1770

1771
	/* Free the needed pages to the hugetlb pool */
1772
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1773 1774
		if ((--needed) < 0)
			break;
1775 1776 1777 1778 1779
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
1780
		VM_BUG_ON_PAGE(page_count(page), page);
1781
		enqueue_huge_page(h, page);
1782
	}
1783
free:
1784
	spin_unlock(&hugetlb_lock);
1785 1786

	/* Free unnecessary surplus pages to the buddy allocator */
1787 1788
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
1789
	spin_lock(&hugetlb_lock);
1790 1791 1792 1793 1794

	return ret;
}

/*
1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806
 * This routine has two main purposes:
 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
 *    in unused_resv_pages.  This corresponds to the prior adjustments made
 *    to the associated reservation map.
 * 2) Free any unused surplus pages that may have been allocated to satisfy
 *    the reservation.  As many as unused_resv_pages may be freed.
 *
 * Called with hugetlb_lock held.  However, the lock could be dropped (and
 * reacquired) during calls to cond_resched_lock.  Whenever dropping the lock,
 * we must make sure nobody else can claim pages we are in the process of
 * freeing.  Do this by ensuring resv_huge_page always is greater than the
 * number of huge pages we plan to free when dropping the lock.
1807
 */
1808 1809
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
1810 1811 1812
{
	unsigned long nr_pages;

1813
	/* Cannot return gigantic pages currently */
1814
	if (hstate_is_gigantic(h))
1815
		goto out;
1816

1817 1818 1819 1820
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
1821
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1822

1823 1824
	/*
	 * We want to release as many surplus pages as possible, spread
1825 1826 1827 1828 1829
	 * 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.
1830 1831 1832 1833
	 *
	 * Note that we decrement resv_huge_pages as we free the pages.  If
	 * we drop the lock, resv_huge_pages will still be sufficiently large
	 * to cover subsequent pages we may free.
1834 1835
	 */
	while (nr_pages--) {
1836 1837
		h->resv_huge_pages--;
		unused_resv_pages--;
1838
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1839
			goto out;
1840
		cond_resched_lock(&hugetlb_lock);
1841
	}
1842 1843 1844 1845

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
1846 1847
}

1848

1849
/*
1850
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1851
 * are used by the huge page allocation routines to manage reservations.
1852 1853 1854 1855 1856 1857
 *
 * vma_needs_reservation is called to determine if the huge page at addr
 * within the vma has an associated reservation.  If a reservation is
 * needed, the value 1 is returned.  The caller is then responsible for
 * managing the global reservation and subpool usage counts.  After
 * the huge page has been allocated, vma_commit_reservation is called
1858 1859 1860
 * to add the page to the reservation map.  If the page allocation fails,
 * the reservation must be ended instead of committed.  vma_end_reservation
 * is called in such cases.
1861 1862 1863 1864 1865 1866
 *
 * In the normal case, vma_commit_reservation returns the same value
 * as the preceding vma_needs_reservation call.  The only time this
 * is not the case is if a reserve map was changed between calls.  It
 * is the responsibility of the caller to notice the difference and
 * take appropriate action.
1867 1868 1869 1870 1871
 *
 * vma_add_reservation is used in error paths where a reservation must
 * be restored when a newly allocated huge page must be freed.  It is
 * to be called after calling vma_needs_reservation to determine if a
 * reservation exists.
1872
 */
1873 1874 1875
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
1876
	VMA_END_RESV,
1877
	VMA_ADD_RESV,
1878
};
1879 1880
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
1881
				enum vma_resv_mode mode)
1882
{
1883 1884
	struct resv_map *resv;
	pgoff_t idx;
1885
	long ret;
1886

1887 1888
	resv = vma_resv_map(vma);
	if (!resv)
1889
		return 1;
1890

1891
	idx = vma_hugecache_offset(h, vma, addr);
1892 1893
	switch (mode) {
	case VMA_NEEDS_RESV:
1894
		ret = region_chg(resv, idx, idx + 1);
1895 1896 1897 1898
		break;
	case VMA_COMMIT_RESV:
		ret = region_add(resv, idx, idx + 1);
		break;
1899
	case VMA_END_RESV:
1900 1901 1902
		region_abort(resv, idx, idx + 1);
		ret = 0;
		break;
1903 1904 1905 1906 1907 1908 1909 1910
	case VMA_ADD_RESV:
		if (vma->vm_flags & VM_MAYSHARE)
			ret = region_add(resv, idx, idx + 1);
		else {
			region_abort(resv, idx, idx + 1);
			ret = region_del(resv, idx, idx + 1);
		}
		break;
1911 1912 1913
	default:
		BUG();
	}
1914

1915
	if (vma->vm_flags & VM_MAYSHARE)
1916
		return ret;
1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935
	else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
		/*
		 * In most cases, reserves always exist for private mappings.
		 * However, a file associated with mapping could have been
		 * hole punched or truncated after reserves were consumed.
		 * As subsequent fault on such a range will not use reserves.
		 * Subtle - The reserve map for private mappings has the
		 * opposite meaning than that of shared mappings.  If NO
		 * entry is in the reserve map, it means a reservation exists.
		 * If an entry exists in the reserve map, it means the
		 * reservation has already been consumed.  As a result, the
		 * return value of this routine is the opposite of the
		 * value returned from reserve map manipulation routines above.
		 */
		if (ret)
			return 0;
		else
			return 1;
	}
1936
	else
1937
		return ret < 0 ? ret : 0;
1938
}
1939 1940

static long vma_needs_reservation(struct hstate *h,
1941
			struct vm_area_struct *vma, unsigned long addr)
1942
{
1943
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1944
}
1945

1946 1947 1948
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
1949 1950 1951
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

1952
static void vma_end_reservation(struct hstate *h,
1953 1954
			struct vm_area_struct *vma, unsigned long addr)
{
1955
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1956 1957
}

1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
static long vma_add_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
	return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
}

/*
 * This routine is called to restore a reservation on error paths.  In the
 * specific error paths, a huge page was allocated (via alloc_huge_page)
 * and is about to be freed.  If a reservation for the page existed,
 * alloc_huge_page would have consumed the reservation and set PagePrivate
 * in the newly allocated page.  When the page is freed via free_huge_page,
 * the global reservation count will be incremented if PagePrivate is set.
 * However, free_huge_page can not adjust the reserve map.  Adjust the
 * reserve map here to be consistent with global reserve count adjustments
 * to be made by free_huge_page.
 */
static void restore_reserve_on_error(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address,
			struct page *page)
{
	if (unlikely(PagePrivate(page))) {
		long rc = vma_needs_reservation(h, vma, address);

		if (unlikely(rc < 0)) {
			/*
			 * Rare out of memory condition in reserve map
			 * manipulation.  Clear PagePrivate so that
			 * global reserve count will not be incremented
			 * by free_huge_page.  This will make it appear
			 * as though the reservation for this page was
			 * consumed.  This may prevent the task from
			 * faulting in the page at a later time.  This
			 * is better than inconsistent global huge page
			 * accounting of reserve counts.
			 */
			ClearPagePrivate(page);
		} else if (rc) {
			rc = vma_add_reservation(h, vma, address);
			if (unlikely(rc < 0))
				/*
				 * See above comment about rare out of
				 * memory condition.
				 */
				ClearPagePrivate(page);
		} else
			vma_end_reservation(h, vma, address);
	}
}

2008
struct page *alloc_huge_page(struct vm_area_struct *vma,
2009
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
2010
{
2011
	struct hugepage_subpool *spool = subpool_vma(vma);
2012
	struct hstate *h = hstate_vma(vma);
2013
	struct page *page;
2014 2015
	long map_chg, map_commit;
	long gbl_chg;
2016 2017
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2018

2019
	idx = hstate_index(h);
2020
	/*
2021 2022 2023
	 * Examine the region/reserve map to determine if the process
	 * has a reservation for the page to be allocated.  A return
	 * code of zero indicates a reservation exists (no change).
2024
	 */
2025 2026
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2027
		return ERR_PTR(-ENOMEM);
2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038

	/*
	 * Processes that did not create the mapping will have no
	 * reserves as indicated by the region/reserve map. Check
	 * that the allocation will not exceed the subpool limit.
	 * Allocations for MAP_NORESERVE mappings also need to be
	 * checked against any subpool limit.
	 */
	if (map_chg || avoid_reserve) {
		gbl_chg = hugepage_subpool_get_pages(spool, 1);
		if (gbl_chg < 0) {
2039
			vma_end_reservation(h, vma, addr);
2040
			return ERR_PTR(-ENOSPC);
2041
		}
L
Linus Torvalds 已提交
2042

2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054
		/*
		 * Even though there was no reservation in the region/reserve
		 * map, there could be reservations associated with the
		 * subpool that can be used.  This would be indicated if the
		 * return value of hugepage_subpool_get_pages() is zero.
		 * However, if avoid_reserve is specified we still avoid even
		 * the subpool reservations.
		 */
		if (avoid_reserve)
			gbl_chg = 1;
	}

2055
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2056 2057 2058
	if (ret)
		goto out_subpool_put;

L
Linus Torvalds 已提交
2059
	spin_lock(&hugetlb_lock);
2060 2061 2062 2063 2064 2065
	/*
	 * glb_chg is passed to indicate whether or not a page must be taken
	 * from the global free pool (global change).  gbl_chg == 0 indicates
	 * a reservation exists for the allocation.
	 */
	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
2066
	if (!page) {
2067
		spin_unlock(&hugetlb_lock);
2068
		page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
2069 2070
		if (!page)
			goto out_uncharge_cgroup;
2071 2072 2073 2074
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2075 2076
		spin_lock(&hugetlb_lock);
		list_move(&page->lru, &h->hugepage_activelist);
2077
		/* Fall through */
K
Ken Chen 已提交
2078
	}
2079 2080
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
	spin_unlock(&hugetlb_lock);
2081

2082
	set_page_private(page, (unsigned long)spool);
2083

2084 2085
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099
		/*
		 * The page was added to the reservation map between
		 * vma_needs_reservation and vma_commit_reservation.
		 * This indicates a race with hugetlb_reserve_pages.
		 * Adjust for the subpool count incremented above AND
		 * in hugetlb_reserve_pages for the same page.  Also,
		 * the reservation count added in hugetlb_reserve_pages
		 * no longer applies.
		 */
		long rsv_adjust;

		rsv_adjust = hugepage_subpool_put_pages(spool, 1);
		hugetlb_acct_memory(h, -rsv_adjust);
	}
2100
	return page;
2101 2102 2103 2104

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
out_subpool_put:
2105
	if (map_chg || avoid_reserve)
2106
		hugepage_subpool_put_pages(spool, 1);
2107
	vma_end_reservation(h, vma, addr);
2108
	return ERR_PTR(-ENOSPC);
2109 2110
}

2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124
/*
 * alloc_huge_page()'s wrapper which simply returns the page if allocation
 * succeeds, otherwise NULL. This function is called from new_vma_page(),
 * where no ERR_VALUE is expected to be returned.
 */
struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
				unsigned long addr, int avoid_reserve)
{
	struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
	if (IS_ERR(page))
		page = NULL;
	return page;
}

2125
int __weak alloc_bootmem_huge_page(struct hstate *h)
2126 2127
{
	struct huge_bootmem_page *m;
2128
	int nr_nodes, node;
2129

2130
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2131 2132
		void *addr;

2133 2134 2135
		addr = memblock_virt_alloc_try_nid_nopanic(
				huge_page_size(h), huge_page_size(h),
				0, BOOTMEM_ALLOC_ACCESSIBLE, node);
2136 2137 2138 2139 2140 2141 2142
		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;
2143
			goto found;
2144 2145 2146 2147 2148
		}
	}
	return 0;

found:
2149
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2150 2151 2152 2153 2154 2155
	/* 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;
}

2156 2157
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2158 2159 2160 2161 2162 2163 2164
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2165 2166 2167 2168 2169 2170 2171
/* 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;
2172 2173 2174 2175
		struct page *page;

#ifdef CONFIG_HIGHMEM
		page = pfn_to_page(m->phys >> PAGE_SHIFT);
2176 2177
		memblock_free_late(__pa(m),
				   sizeof(struct huge_bootmem_page));
2178 2179 2180
#else
		page = virt_to_page(m);
#endif
2181
		WARN_ON(page_count(page) != 1);
2182
		prep_compound_huge_page(page, h->order);
2183
		WARN_ON(PageReserved(page));
2184
		prep_new_huge_page(h, page, page_to_nid(page));
2185 2186 2187 2188 2189 2190
		/*
		 * 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.
		 */
2191
		if (hstate_is_gigantic(h))
2192
			adjust_managed_page_count(page, 1 << h->order);
2193 2194 2195
	}
}

2196
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2197 2198
{
	unsigned long i;
2199

2200
	for (i = 0; i < h->max_huge_pages; ++i) {
2201
		if (hstate_is_gigantic(h)) {
2202 2203
			if (!alloc_bootmem_huge_page(h))
				break;
2204
		} else if (!alloc_fresh_huge_page(h,
2205
					 &node_states[N_MEMORY]))
L
Linus Torvalds 已提交
2206 2207
			break;
	}
2208
	h->max_huge_pages = i;
2209 2210 2211 2212 2213 2214 2215
}

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

	for_each_hstate(h) {
2216 2217 2218
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2219
		/* oversize hugepages were init'ed in early boot */
2220
		if (!hstate_is_gigantic(h))
2221
			hugetlb_hstate_alloc_pages(h);
2222
	}
2223
	VM_BUG_ON(minimum_order == UINT_MAX);
2224 2225
}

A
Andi Kleen 已提交
2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236
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;
}

2237 2238 2239 2240 2241
static void __init report_hugepages(void)
{
	struct hstate *h;

	for_each_hstate(h) {
A
Andi Kleen 已提交
2242
		char buf[32];
2243
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
A
Andi Kleen 已提交
2244 2245
			memfmt(buf, huge_page_size(h)),
			h->free_huge_pages);
2246 2247 2248
	}
}

L
Linus Torvalds 已提交
2249
#ifdef CONFIG_HIGHMEM
2250 2251
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2252
{
2253 2254
	int i;

2255
	if (hstate_is_gigantic(h))
2256 2257
		return;

2258
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2259
		struct page *page, *next;
2260 2261 2262
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2263
				return;
L
Linus Torvalds 已提交
2264 2265 2266
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2267
			update_and_free_page(h, page);
2268 2269
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2270 2271 2272 2273
		}
	}
}
#else
2274 2275
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2276 2277 2278 2279
{
}
#endif

2280 2281 2282 2283 2284
/*
 * 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.
 */
2285 2286
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2287
{
2288
	int nr_nodes, node;
2289 2290 2291

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

2292 2293 2294 2295
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2296
		}
2297 2298 2299 2300 2301
	} else {
		for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node] <
					h->nr_huge_pages_node[node])
				goto found;
2302
		}
2303 2304
	}
	return 0;
2305

2306 2307 2308 2309
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2310 2311
}

2312
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2313 2314
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2315
{
2316
	unsigned long min_count, ret;
L
Linus Torvalds 已提交
2317

2318
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
2319 2320
		return h->max_huge_pages;

2321 2322 2323 2324
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2325
	 *
N
Naoya Horiguchi 已提交
2326
	 * We might race with __alloc_buddy_huge_page() here and be unable
2327 2328 2329 2330
	 * 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.
2331
	 */
L
Linus Torvalds 已提交
2332
	spin_lock(&hugetlb_lock);
2333
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2334
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2335 2336 2337
			break;
	}

2338
	while (count > persistent_huge_pages(h)) {
2339 2340 2341 2342 2343 2344
		/*
		 * 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);
2345 2346 2347 2348

		/* yield cpu to avoid soft lockup */
		cond_resched();

2349 2350 2351 2352
		if (hstate_is_gigantic(h))
			ret = alloc_fresh_gigantic_page(h, nodes_allowed);
		else
			ret = alloc_fresh_huge_page(h, nodes_allowed);
2353 2354 2355 2356
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2357 2358 2359
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2360 2361 2362 2363 2364 2365 2366 2367
	}

	/*
	 * 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.
2368 2369 2370 2371
	 *
	 * 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
N
Naoya Horiguchi 已提交
2372
	 * __alloc_buddy_huge_page() is checking the global counter,
2373 2374 2375
	 * 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.
2376
	 */
2377
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2378
	min_count = max(count, min_count);
2379
	try_to_free_low(h, min_count, nodes_allowed);
2380
	while (min_count < persistent_huge_pages(h)) {
2381
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2382
			break;
2383
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2384
	}
2385
	while (count < persistent_huge_pages(h)) {
2386
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2387 2388 2389
			break;
	}
out:
2390
	ret = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2391
	spin_unlock(&hugetlb_lock);
2392
	return ret;
L
Linus Torvalds 已提交
2393 2394
}

2395 2396 2397 2398 2399 2400 2401 2402 2403 2404
#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];

2405 2406 2407
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2408 2409
{
	int i;
2410

2411
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2412 2413 2414
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2415
			return &hstates[i];
2416 2417 2418
		}

	return kobj_to_node_hstate(kobj, nidp);
2419 2420
}

2421
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2422 2423
					struct kobj_attribute *attr, char *buf)
{
2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434
	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);
2435
}
2436

2437 2438 2439
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2440 2441
{
	int err;
2442
	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2443

2444
	if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2445 2446 2447 2448
		err = -EINVAL;
		goto out;
	}

2449 2450 2451 2452 2453 2454 2455
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
				init_nodemask_of_mempolicy(nodes_allowed))) {
			NODEMASK_FREE(nodes_allowed);
2456
			nodes_allowed = &node_states[N_MEMORY];
2457 2458 2459 2460 2461 2462 2463 2464 2465
		}
	} 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
2466
		nodes_allowed = &node_states[N_MEMORY];
2467

2468
	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2469

2470
	if (nodes_allowed != &node_states[N_MEMORY])
2471 2472 2473
		NODEMASK_FREE(nodes_allowed);

	return len;
2474 2475 2476
out:
	NODEMASK_FREE(nodes_allowed);
	return err;
2477 2478
}

2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495
static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
					 struct kobject *kobj, const char *buf,
					 size_t len)
{
	struct hstate *h;
	unsigned long count;
	int nid;
	int err;

	err = kstrtoul(buf, 10, &count);
	if (err)
		return err;

	h = kobj_to_hstate(kobj, &nid);
	return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
}

2496 2497 2498 2499 2500 2501 2502 2503 2504
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)
{
2505
	return nr_hugepages_store_common(false, kobj, buf, len);
2506 2507 2508
}
HSTATE_ATTR(nr_hugepages);

2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523
#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)
{
2524
	return nr_hugepages_store_common(true, kobj, buf, len);
2525 2526 2527 2528 2529
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2530 2531 2532
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2533
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2534 2535
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2536

2537 2538 2539 2540 2541
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;
2542
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2543

2544
	if (hstate_is_gigantic(h))
2545 2546
		return -EINVAL;

2547
	err = kstrtoul(buf, 10, &input);
2548
	if (err)
2549
		return err;
2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561

	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)
{
2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572
	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);
2573 2574 2575 2576 2577 2578
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2579
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2580 2581 2582 2583 2584 2585 2586
	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)
{
2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597
	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);
2598 2599 2600 2601 2602 2603 2604 2605 2606
}
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,
2607 2608 2609
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2610 2611 2612 2613 2614 2615 2616
	NULL,
};

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

J
Jeff Mahoney 已提交
2617 2618 2619
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
				    struct attribute_group *hstate_attr_group)
2620 2621
{
	int retval;
2622
	int hi = hstate_index(h);
2623

2624 2625
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
2626 2627
		return -ENOMEM;

2628
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2629
	if (retval)
2630
		kobject_put(hstate_kobjs[hi]);
2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644

	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) {
2645 2646
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
2647
		if (err)
2648
			pr_err("Hugetlb: Unable to add hstate %s", h->name);
2649 2650 2651
	}
}

2652 2653 2654 2655
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2656 2657 2658
 * 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
2659 2660 2661 2662 2663 2664
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
2665
static struct node_hstate node_hstates[MAX_NUMNODES];
2666 2667

/*
2668
 * A subset of global hstate attributes for node devices
2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681
 */
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,
};

/*
2682
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704
 * 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;
}

/*
2705
 * Unregister hstate attributes from a single node device.
2706 2707
 * No-op if no hstate attributes attached.
 */
2708
static void hugetlb_unregister_node(struct node *node)
2709 2710
{
	struct hstate *h;
2711
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2712 2713

	if (!nhs->hugepages_kobj)
2714
		return;		/* no hstate attributes */
2715

2716 2717 2718 2719 2720
	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;
2721
		}
2722
	}
2723 2724 2725 2726 2727 2728 2729

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


/*
2730
 * Register hstate attributes for a single node device.
2731 2732
 * No-op if attributes already registered.
 */
2733
static void hugetlb_register_node(struct node *node)
2734 2735
{
	struct hstate *h;
2736
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2737 2738 2739 2740 2741 2742
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2743
							&node->dev.kobj);
2744 2745 2746 2747 2748 2749 2750 2751
	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) {
2752 2753
			pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
				h->name, node->dev.id);
2754 2755 2756 2757 2758 2759 2760
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
2761
 * hugetlb init time:  register hstate attributes for all registered node
2762 2763
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
2764
 */
2765
static void __init hugetlb_register_all_nodes(void)
2766 2767 2768
{
	int nid;

2769
	for_each_node_state(nid, N_MEMORY) {
2770
		struct node *node = node_devices[nid];
2771
		if (node->dev.id == nid)
2772 2773 2774 2775
			hugetlb_register_node(node);
	}

	/*
2776
	 * Let the node device driver know we're here so it can
2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795
	 * [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_register_all_nodes(void) { }

#endif

2796 2797
static int __init hugetlb_init(void)
{
2798 2799
	int i;

2800
	if (!hugepages_supported())
2801
		return 0;
2802

2803 2804 2805 2806
	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);
2807
	}
2808
	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2809 2810 2811 2812
	if (default_hstate_max_huge_pages) {
		if (!default_hstate.max_huge_pages)
			default_hstate.max_huge_pages = default_hstate_max_huge_pages;
	}
2813 2814

	hugetlb_init_hstates();
2815
	gather_bootmem_prealloc();
2816 2817 2818
	report_hugepages();

	hugetlb_sysfs_init();
2819
	hugetlb_register_all_nodes();
2820
	hugetlb_cgroup_file_init();
2821

2822 2823 2824 2825 2826
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
2827
	hugetlb_fault_mutex_table =
2828
		kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2829
	BUG_ON(!hugetlb_fault_mutex_table);
2830 2831

	for (i = 0; i < num_fault_mutexes; i++)
2832
		mutex_init(&hugetlb_fault_mutex_table[i]);
2833 2834
	return 0;
}
2835
subsys_initcall(hugetlb_init);
2836 2837

/* Should be called on processing a hugepagesz=... option */
2838 2839 2840 2841 2842
void __init hugetlb_bad_size(void)
{
	parsed_valid_hugepagesz = false;
}

2843
void __init hugetlb_add_hstate(unsigned int order)
2844 2845
{
	struct hstate *h;
2846 2847
	unsigned long i;

2848
	if (size_to_hstate(PAGE_SIZE << order)) {
J
Joe Perches 已提交
2849
		pr_warn("hugepagesz= specified twice, ignoring\n");
2850 2851
		return;
	}
2852
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2853
	BUG_ON(order == 0);
2854
	h = &hstates[hugetlb_max_hstate++];
2855 2856
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2857 2858 2859 2860
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2861
	INIT_LIST_HEAD(&h->hugepage_activelist);
2862 2863
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
2864 2865
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
2866

2867 2868 2869
	parsed_hstate = h;
}

2870
static int __init hugetlb_nrpages_setup(char *s)
2871 2872
{
	unsigned long *mhp;
2873
	static unsigned long *last_mhp;
2874

2875 2876 2877 2878 2879 2880
	if (!parsed_valid_hugepagesz) {
		pr_warn("hugepages = %s preceded by "
			"an unsupported hugepagesz, ignoring\n", s);
		parsed_valid_hugepagesz = true;
		return 1;
	}
2881
	/*
2882
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2883 2884
	 * so this hugepages= parameter goes to the "default hstate".
	 */
2885
	else if (!hugetlb_max_hstate)
2886 2887 2888 2889
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

2890
	if (mhp == last_mhp) {
J
Joe Perches 已提交
2891
		pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2892 2893 2894
		return 1;
	}

2895 2896 2897
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

2898 2899 2900 2901 2902
	/*
	 * 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.
	 */
2903
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2904 2905 2906 2907
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

2908 2909
	return 1;
}
2910 2911 2912 2913 2914 2915 2916 2917
__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);
2918

2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930
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
2931 2932 2933
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
2934
{
2935
	struct hstate *h = &default_hstate;
2936
	unsigned long tmp = h->max_huge_pages;
2937
	int ret;
2938

2939
	if (!hugepages_supported())
2940
		return -EOPNOTSUPP;
2941

2942 2943
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2944 2945 2946
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2947

2948 2949 2950
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
2951 2952
out:
	return ret;
L
Linus Torvalds 已提交
2953
}
2954

2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971
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 */

2972
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2973
			void __user *buffer,
2974 2975
			size_t *length, loff_t *ppos)
{
2976
	struct hstate *h = &default_hstate;
2977
	unsigned long tmp;
2978
	int ret;
2979

2980
	if (!hugepages_supported())
2981
		return -EOPNOTSUPP;
2982

2983
	tmp = h->nr_overcommit_huge_pages;
2984

2985
	if (write && hstate_is_gigantic(h))
2986 2987
		return -EINVAL;

2988 2989
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2990 2991 2992
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2993 2994 2995 2996 2997 2998

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
2999 3000
out:
	return ret;
3001 3002
}

L
Linus Torvalds 已提交
3003 3004
#endif /* CONFIG_SYSCTL */

3005
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
3006
{
3007
	struct hstate *h = &default_hstate;
3008 3009
	if (!hugepages_supported())
		return;
3010
	seq_printf(m,
3011 3012 3013 3014 3015
			"HugePages_Total:   %5lu\n"
			"HugePages_Free:    %5lu\n"
			"HugePages_Rsvd:    %5lu\n"
			"HugePages_Surp:    %5lu\n"
			"Hugepagesize:   %8lu kB\n",
3016 3017 3018 3019 3020
			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
3021 3022 3023 3024
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
3025
	struct hstate *h = &default_hstate;
3026 3027
	if (!hugepages_supported())
		return 0;
L
Linus Torvalds 已提交
3028 3029
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
3030 3031
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
3032 3033 3034
		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
3035 3036
}

3037 3038 3039 3040 3041
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

3042 3043 3044
	if (!hugepages_supported())
		return;

3045 3046 3047 3048 3049 3050 3051 3052 3053 3054
	for_each_node_state(nid, N_MEMORY)
		for_each_hstate(h)
			pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
				nid,
				h->nr_huge_pages_node[nid],
				h->free_huge_pages_node[nid],
				h->surplus_huge_pages_node[nid],
				1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
}

3055 3056 3057 3058 3059 3060
void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
{
	seq_printf(m, "HugetlbPages:\t%8lu kB\n",
		   atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
}

L
Linus Torvalds 已提交
3061 3062 3063
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
3064 3065 3066 3067 3068 3069
	struct hstate *h;
	unsigned long nr_total_pages = 0;

	for_each_hstate(h)
		nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
	return nr_total_pages;
L
Linus Torvalds 已提交
3070 3071
}

3072
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094
{
	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) {
3095
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3096 3097
			goto out;

3098 3099
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3100 3101 3102 3103 3104 3105
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3106
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3107 3108 3109 3110 3111 3112

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

3113 3114
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3115
	struct resv_map *resv = vma_resv_map(vma);
3116 3117 3118 3119 3120

	/*
	 * 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
3121
	 * has a reference to the reservation map it cannot disappear until
3122 3123 3124
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3125
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3126
		kref_get(&resv->refs);
3127 3128
}

3129 3130
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3131
	struct hstate *h = hstate_vma(vma);
3132
	struct resv_map *resv = vma_resv_map(vma);
3133
	struct hugepage_subpool *spool = subpool_vma(vma);
3134
	unsigned long reserve, start, end;
3135
	long gbl_reserve;
3136

3137 3138
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3139

3140 3141
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3142

3143
	reserve = (end - start) - region_count(resv, start, end);
3144

3145 3146 3147
	kref_put(&resv->refs, resv_map_release);

	if (reserve) {
3148 3149 3150 3151 3152 3153
		/*
		 * Decrement reserve counts.  The global reserve count may be
		 * adjusted if the subpool has a minimum size.
		 */
		gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
		hugetlb_acct_memory(h, -gbl_reserve);
3154
	}
3155 3156
}

L
Linus Torvalds 已提交
3157 3158 3159 3160 3161 3162
/*
 * 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.
 */
3163
static int hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3164 3165
{
	BUG();
N
Nick Piggin 已提交
3166
	return 0;
L
Linus Torvalds 已提交
3167 3168
}

3169
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3170
	.fault = hugetlb_vm_op_fault,
3171
	.open = hugetlb_vm_op_open,
3172
	.close = hugetlb_vm_op_close,
L
Linus Torvalds 已提交
3173 3174
};

3175 3176
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3177 3178 3179
{
	pte_t entry;

3180
	if (writable) {
3181 3182
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3183
	} else {
3184 3185
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3186 3187 3188
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3189
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3190 3191 3192 3193

	return entry;
}

3194 3195 3196 3197 3198
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3199
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3200
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3201
		update_mmu_cache(vma, address, ptep);
3202 3203
}

3204
bool is_hugetlb_entry_migration(pte_t pte)
3205 3206 3207 3208
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3209
		return false;
3210 3211
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_migration_entry(swp))
3212
		return true;
3213
	else
3214
		return false;
3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228
}

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);
	if (non_swap_entry(swp) && is_hwpoison_entry(swp))
		return 1;
	else
		return 0;
}
3229

D
David Gibson 已提交
3230 3231 3232 3233 3234
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;
3235
	unsigned long addr;
3236
	int cow;
3237 3238
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3239 3240 3241
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
	int ret = 0;
3242 3243

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3244

3245 3246 3247 3248 3249
	mmun_start = vma->vm_start;
	mmun_end = vma->vm_end;
	if (cow)
		mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);

3250
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3251
		spinlock_t *src_ptl, *dst_ptl;
H
Hugh Dickins 已提交
3252 3253 3254
		src_pte = huge_pte_offset(src, addr);
		if (!src_pte)
			continue;
3255
		dst_pte = huge_pte_alloc(dst, addr, sz);
3256 3257 3258 3259
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3260 3261 3262 3263 3264

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

3265 3266 3267
		dst_ptl = huge_pte_lock(h, dst, dst_pte);
		src_ptl = huge_pte_lockptr(h, src, src_pte);
		spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285
		entry = huge_ptep_get(src_pte);
		if (huge_pte_none(entry)) { /* skip none entry */
			;
		} else if (unlikely(is_hugetlb_entry_migration(entry) ||
				    is_hugetlb_entry_hwpoisoned(entry))) {
			swp_entry_t swp_entry = pte_to_swp_entry(entry);

			if (is_write_migration_entry(swp_entry) && cow) {
				/*
				 * COW mappings require pages in both
				 * parent and child to be set to read.
				 */
				make_migration_entry_read(&swp_entry);
				entry = swp_entry_to_pte(swp_entry);
				set_huge_pte_at(src, addr, src_pte, entry);
			}
			set_huge_pte_at(dst, addr, dst_pte, entry);
		} else {
3286
			if (cow) {
3287
				huge_ptep_set_wrprotect(src, addr, src_pte);
3288 3289 3290
				mmu_notifier_invalidate_range(src, mmun_start,
								   mmun_end);
			}
3291
			entry = huge_ptep_get(src_pte);
3292 3293
			ptepage = pte_page(entry);
			get_page(ptepage);
3294
			page_dup_rmap(ptepage, true);
3295
			set_huge_pte_at(dst, addr, dst_pte, entry);
3296
			hugetlb_count_add(pages_per_huge_page(h), dst);
3297
		}
3298 3299
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3300 3301
	}

3302 3303 3304 3305
	if (cow)
		mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);

	return ret;
D
David Gibson 已提交
3306 3307
}

3308 3309 3310
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
3311 3312 3313
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3314
	pte_t *ptep;
D
David Gibson 已提交
3315
	pte_t pte;
3316
	spinlock_t *ptl;
D
David Gibson 已提交
3317
	struct page *page;
3318 3319
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3320 3321
	const unsigned long mmun_start = start;	/* For mmu_notifiers */
	const unsigned long mmun_end   = end;	/* For mmu_notifiers */
3322

D
David Gibson 已提交
3323
	WARN_ON(!is_vm_hugetlb_page(vma));
3324 3325
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3326

3327 3328 3329 3330 3331
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
	tlb_remove_check_page_size_change(tlb, sz);
3332
	tlb_start_vma(tlb, vma);
3333
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3334 3335
	address = start;
	for (; address < end; address += sz) {
3336
		ptep = huge_pte_offset(mm, address);
A
Adam Litke 已提交
3337
		if (!ptep)
3338 3339
			continue;

3340
		ptl = huge_pte_lock(h, mm, ptep);
3341 3342 3343 3344
		if (huge_pmd_unshare(mm, &address, ptep)) {
			spin_unlock(ptl);
			continue;
		}
3345

3346
		pte = huge_ptep_get(ptep);
3347 3348 3349 3350
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3351 3352

		/*
3353 3354
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3355
		 */
3356
		if (unlikely(!pte_present(pte))) {
3357
			huge_pte_clear(mm, address, ptep);
3358 3359
			spin_unlock(ptl);
			continue;
3360
		}
3361 3362

		page = pte_page(pte);
3363 3364 3365 3366 3367 3368
		/*
		 * 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) {
3369 3370 3371 3372
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3373 3374 3375 3376 3377 3378 3379 3380
			/*
			 * 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);
		}

3381
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3382
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3383
		if (huge_pte_dirty(pte))
3384
			set_page_dirty(page);
3385

3386
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3387
		page_remove_rmap(page, true);
3388

3389
		spin_unlock(ptl);
3390
		tlb_remove_page_size(tlb, page, huge_page_size(h));
3391 3392 3393 3394 3395
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
3396
	}
3397
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3398
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
3399
}
D
David Gibson 已提交
3400

3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412
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
3413
	 * is to clear it before releasing the i_mmap_rwsem. This works
3414
	 * because in the context this is called, the VMA is about to be
3415
	 * destroyed and the i_mmap_rwsem is held.
3416 3417 3418 3419
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

3420
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3421
			  unsigned long end, struct page *ref_page)
3422
{
3423 3424 3425 3426 3427
	struct mm_struct *mm;
	struct mmu_gather tlb;

	mm = vma->vm_mm;

3428
	tlb_gather_mmu(&tlb, mm, start, end);
3429 3430
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
	tlb_finish_mmu(&tlb, start, end);
3431 3432
}

3433 3434 3435 3436 3437 3438
/*
 * 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.
 */
3439 3440
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
3441
{
3442
	struct hstate *h = hstate_vma(vma);
3443 3444 3445 3446 3447 3448 3449 3450
	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.
	 */
3451
	address = address & huge_page_mask(h);
3452 3453
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
3454
	mapping = vma->vm_file->f_mapping;
3455

3456 3457 3458 3459 3460
	/*
	 * 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
	 */
3461
	i_mmap_lock_write(mapping);
3462
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3463 3464 3465 3466
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

3467 3468 3469 3470 3471 3472 3473 3474
		/*
		 * Shared VMAs have their own reserves and do not affect
		 * MAP_PRIVATE accounting but it is possible that a shared
		 * VMA is using the same page so check and skip such VMAs.
		 */
		if (iter_vma->vm_flags & VM_MAYSHARE)
			continue;

3475 3476 3477 3478 3479 3480 3481 3482
		/*
		 * 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))
3483 3484
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
3485
	}
3486
	i_mmap_unlock_write(mapping);
3487 3488
}

3489 3490
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3491 3492 3493
 * 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.
3494
 */
3495
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3496 3497
		       unsigned long address, pte_t *ptep,
		       struct page *pagecache_page, spinlock_t *ptl)
3498
{
3499
	pte_t pte;
3500
	struct hstate *h = hstate_vma(vma);
3501
	struct page *old_page, *new_page;
3502
	int ret = 0, outside_reserve = 0;
3503 3504
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
3505

3506
	pte = huge_ptep_get(ptep);
3507 3508
	old_page = pte_page(pte);

3509
retry_avoidcopy:
3510 3511
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
3512
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3513
		page_move_anon_rmap(old_page, vma);
3514
		set_huge_ptep_writable(vma, address, ptep);
N
Nick Piggin 已提交
3515
		return 0;
3516 3517
	}

3518 3519 3520 3521 3522 3523 3524 3525 3526
	/*
	 * 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.
	 */
3527
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3528 3529 3530
			old_page != pagecache_page)
		outside_reserve = 1;

3531
	get_page(old_page);
3532

3533 3534 3535 3536
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
3537
	spin_unlock(ptl);
3538
	new_page = alloc_huge_page(vma, address, outside_reserve);
3539

3540
	if (IS_ERR(new_page)) {
3541 3542 3543 3544 3545 3546 3547 3548
		/*
		 * 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) {
3549
			put_page(old_page);
3550
			BUG_ON(huge_pte_none(pte));
3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562
			unmap_ref_private(mm, vma, old_page, address);
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
			ptep = huge_pte_offset(mm, address & huge_page_mask(h));
			if (likely(ptep &&
				   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;
3563 3564
		}

3565 3566 3567
		ret = (PTR_ERR(new_page) == -ENOMEM) ?
			VM_FAULT_OOM : VM_FAULT_SIGBUS;
		goto out_release_old;
3568 3569
	}

3570 3571 3572 3573
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
3574
	if (unlikely(anon_vma_prepare(vma))) {
3575 3576
		ret = VM_FAULT_OOM;
		goto out_release_all;
3577
	}
3578

A
Andrea Arcangeli 已提交
3579 3580
	copy_user_huge_page(new_page, old_page, address, vma,
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
3581
	__SetPageUptodate(new_page);
3582
	set_page_huge_active(new_page);
3583

3584 3585 3586
	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);
3587

3588
	/*
3589
	 * Retake the page table lock to check for racing updates
3590 3591
	 * before the page tables are altered
	 */
3592
	spin_lock(ptl);
3593
	ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3594
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3595 3596
		ClearPagePrivate(new_page);

3597
		/* Break COW */
3598
		huge_ptep_clear_flush(vma, address, ptep);
3599
		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3600 3601
		set_huge_pte_at(mm, address, ptep,
				make_huge_pte(vma, new_page, 1));
3602
		page_remove_rmap(old_page, true);
3603
		hugepage_add_new_anon_rmap(new_page, vma, address);
3604 3605 3606
		/* Make the old page be freed below */
		new_page = old_page;
	}
3607
	spin_unlock(ptl);
3608
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3609
out_release_all:
3610
	restore_reserve_on_error(h, vma, address, new_page);
3611
	put_page(new_page);
3612
out_release_old:
3613
	put_page(old_page);
3614

3615 3616
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
3617 3618
}

3619
/* Return the pagecache page at a given address within a VMA */
3620 3621
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
3622 3623
{
	struct address_space *mapping;
3624
	pgoff_t idx;
3625 3626

	mapping = vma->vm_file->f_mapping;
3627
	idx = vma_hugecache_offset(h, vma, address);
3628 3629 3630 3631

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
3632 3633 3634 3635 3636
/*
 * 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
3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647 3648 3649 3650 3651
			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;
}

3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668
int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
			   pgoff_t idx)
{
	struct inode *inode = mapping->host;
	struct hstate *h = hstate_inode(inode);
	int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);

	if (err)
		return err;
	ClearPagePrivate(page);

	spin_lock(&inode->i_lock);
	inode->i_blocks += blocks_per_huge_page(h);
	spin_unlock(&inode->i_lock);
	return 0;
}

3669
static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3670 3671
			   struct address_space *mapping, pgoff_t idx,
			   unsigned long address, pte_t *ptep, unsigned int flags)
3672
{
3673
	struct hstate *h = hstate_vma(vma);
3674
	int ret = VM_FAULT_SIGBUS;
3675
	int anon_rmap = 0;
A
Adam Litke 已提交
3676 3677
	unsigned long size;
	struct page *page;
3678
	pte_t new_pte;
3679
	spinlock_t *ptl;
A
Adam Litke 已提交
3680

3681 3682 3683
	/*
	 * 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
3684
	 * COW. Warn that such a situation has occurred as it may not be obvious
3685 3686
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3687
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3688
			   current->pid);
3689 3690 3691
		return ret;
	}

A
Adam Litke 已提交
3692 3693 3694 3695
	/*
	 * Use page lock to guard against racing truncation
	 * before we get page_table_lock.
	 */
3696 3697 3698
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
3699
		size = i_size_read(mapping->host) >> huge_page_shift(h);
3700 3701
		if (idx >= size)
			goto out;
3702 3703 3704 3705 3706 3707 3708 3709 3710 3711 3712 3713 3714 3715 3716 3717 3718 3719 3720 3721 3722 3723 3724 3725 3726 3727 3728 3729 3730 3731 3732 3733

		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
				.address = address,
				.flags = flags,
				/*
				 * Hard to debug if it ends up being
				 * used by a callee that assumes
				 * something about the other
				 * uninitialized fields... same as in
				 * memory.c
				 */
			};

			/*
			 * hugetlb_fault_mutex must be dropped before
			 * handling userfault.  Reacquire after handling
			 * fault to make calling code simpler.
			 */
			hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping,
							idx, address);
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

3734
		page = alloc_huge_page(vma, address, 0);
3735
		if (IS_ERR(page)) {
3736 3737 3738 3739 3740
			ret = PTR_ERR(page);
			if (ret == -ENOMEM)
				ret = VM_FAULT_OOM;
			else
				ret = VM_FAULT_SIGBUS;
3741 3742
			goto out;
		}
A
Andrea Arcangeli 已提交
3743
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
3744
		__SetPageUptodate(page);
3745
		set_page_huge_active(page);
3746

3747
		if (vma->vm_flags & VM_MAYSHARE) {
3748
			int err = huge_add_to_page_cache(page, mapping, idx);
3749 3750 3751 3752 3753 3754
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
3755
		} else {
3756
			lock_page(page);
3757 3758 3759 3760
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
3761
			anon_rmap = 1;
3762
		}
3763
	} else {
3764 3765 3766 3767 3768 3769
		/*
		 * 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))) {
3770
			ret = VM_FAULT_HWPOISON |
3771
				VM_FAULT_SET_HINDEX(hstate_index(h));
3772 3773
			goto backout_unlocked;
		}
3774
	}
3775

3776 3777 3778 3779 3780 3781
	/*
	 * 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.
	 */
3782
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3783 3784 3785 3786
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
3787
		/* Just decrements count, does not deallocate */
3788
		vma_end_reservation(h, vma, address);
3789
	}
3790

3791
	ptl = huge_pte_lock(h, mm, ptep);
3792
	size = i_size_read(mapping->host) >> huge_page_shift(h);
A
Adam Litke 已提交
3793 3794 3795
	if (idx >= size)
		goto backout;

N
Nick Piggin 已提交
3796
	ret = 0;
3797
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
3798 3799
		goto backout;

3800 3801
	if (anon_rmap) {
		ClearPagePrivate(page);
3802
		hugepage_add_new_anon_rmap(page, vma, address);
3803
	} else
3804
		page_dup_rmap(page, true);
3805 3806 3807 3808
	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);

3809
	hugetlb_count_add(pages_per_huge_page(h), mm);
3810
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3811
		/* Optimization, do the COW without a second fault */
3812
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
3813 3814
	}

3815
	spin_unlock(ptl);
A
Adam Litke 已提交
3816 3817
	unlock_page(page);
out:
3818
	return ret;
A
Adam Litke 已提交
3819 3820

backout:
3821
	spin_unlock(ptl);
3822
backout_unlocked:
A
Adam Litke 已提交
3823
	unlock_page(page);
3824
	restore_reserve_on_error(h, vma, address, page);
A
Adam Litke 已提交
3825 3826
	put_page(page);
	goto out;
3827 3828
}

3829
#ifdef CONFIG_SMP
3830
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3831 3832 3833 3834 3835 3836 3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850 3851 3852 3853 3854
			    struct vm_area_struct *vma,
			    struct address_space *mapping,
			    pgoff_t idx, unsigned long address)
{
	unsigned long key[2];
	u32 hash;

	if (vma->vm_flags & VM_SHARED) {
		key[0] = (unsigned long) mapping;
		key[1] = idx;
	} else {
		key[0] = (unsigned long) mm;
		key[1] = address >> huge_page_shift(h);
	}

	hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);

	return hash & (num_fault_mutexes - 1);
}
#else
/*
 * For uniprocesor systems we always use a single mutex, so just
 * return 0 and avoid the hashing overhead.
 */
3855
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3856 3857 3858 3859 3860 3861 3862 3863
			    struct vm_area_struct *vma,
			    struct address_space *mapping,
			    pgoff_t idx, unsigned long address)
{
	return 0;
}
#endif

3864
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3865
			unsigned long address, unsigned int flags)
3866
{
3867
	pte_t *ptep, entry;
3868
	spinlock_t *ptl;
3869
	int ret;
3870 3871
	u32 hash;
	pgoff_t idx;
3872
	struct page *page = NULL;
3873
	struct page *pagecache_page = NULL;
3874
	struct hstate *h = hstate_vma(vma);
3875
	struct address_space *mapping;
3876
	int need_wait_lock = 0;
3877

3878 3879
	address &= huge_page_mask(h);

3880 3881 3882
	ptep = huge_pte_offset(mm, address);
	if (ptep) {
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
3883
		if (unlikely(is_hugetlb_entry_migration(entry))) {
3884
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
3885 3886
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3887
			return VM_FAULT_HWPOISON_LARGE |
3888
				VM_FAULT_SET_HINDEX(hstate_index(h));
3889 3890 3891 3892
	} else {
		ptep = huge_pte_alloc(mm, address, huge_page_size(h));
		if (!ptep)
			return VM_FAULT_OOM;
3893 3894
	}

3895 3896 3897
	mapping = vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, vma, address);

3898 3899 3900 3901 3902
	/*
	 * 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.
	 */
3903 3904
	hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
3905

3906 3907
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
3908
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3909
		goto out_mutex;
3910
	}
3911

N
Nick Piggin 已提交
3912
	ret = 0;
3913

3914 3915 3916 3917 3918 3919 3920 3921 3922 3923
	/*
	 * entry could be a migration/hwpoison entry at this point, so this
	 * check prevents the kernel from going below assuming that we have
	 * a active hugepage in pagecache. This goto expects the 2nd page fault,
	 * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
	 * handle it.
	 */
	if (!pte_present(entry))
		goto out_mutex;

3924 3925 3926 3927 3928 3929 3930 3931
	/*
	 * 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.
	 */
3932
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3933 3934
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
3935
			goto out_mutex;
3936
		}
3937
		/* Just decrements count, does not deallocate */
3938
		vma_end_reservation(h, vma, address);
3939

3940
		if (!(vma->vm_flags & VM_MAYSHARE))
3941 3942 3943 3944
			pagecache_page = hugetlbfs_pagecache_page(h,
								vma, address);
	}

3945 3946 3947 3948 3949 3950
	ptl = huge_pte_lock(h, mm, ptep);

	/* Check for a racing update before calling hugetlb_cow */
	if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
		goto out_ptl;

3951 3952 3953 3954 3955 3956 3957
	/*
	 * 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.
	 */
	page = pte_page(entry);
	if (page != pagecache_page)
3958 3959 3960 3961
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
3962

3963
	get_page(page);
3964

3965
	if (flags & FAULT_FLAG_WRITE) {
3966
		if (!huge_pte_write(entry)) {
3967 3968
			ret = hugetlb_cow(mm, vma, address, ptep,
					  pagecache_page, ptl);
3969
			goto out_put_page;
3970
		}
3971
		entry = huge_pte_mkdirty(entry);
3972 3973
	}
	entry = pte_mkyoung(entry);
3974 3975
	if (huge_ptep_set_access_flags(vma, address, ptep, entry,
						flags & FAULT_FLAG_WRITE))
3976
		update_mmu_cache(vma, address, ptep);
3977 3978 3979 3980
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
3981 3982
out_ptl:
	spin_unlock(ptl);
3983 3984 3985 3986 3987

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
3988
out_mutex:
3989
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3990 3991 3992 3993 3994 3995 3996 3997 3998
	/*
	 * Generally it's safe to hold refcount during waiting page lock. But
	 * here we just wait to defer the next page fault to avoid busy loop and
	 * the page is not used after unlocked before returning from the current
	 * page fault. So we are safe from accessing freed page, even if we wait
	 * here without taking refcount.
	 */
	if (need_wait_lock)
		wait_on_page_locked(page);
3999
	return ret;
4000 4001
}

4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012
/*
 * Used by userfaultfd UFFDIO_COPY.  Based on mcopy_atomic_pte with
 * modifications for huge pages.
 */
int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
			    pte_t *dst_pte,
			    struct vm_area_struct *dst_vma,
			    unsigned long dst_addr,
			    unsigned long src_addr,
			    struct page **pagep)
{
4013
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024 4025 4026 4027
	struct hstate *h = hstate_vma(dst_vma);
	pte_t _dst_pte;
	spinlock_t *ptl;
	int ret;
	struct page *page;

	if (!*pagep) {
		ret = -ENOMEM;
		page = alloc_huge_page(dst_vma, dst_addr, 0);
		if (IS_ERR(page))
			goto out;

		ret = copy_huge_page_from_user(page,
						(const void __user *) src_addr,
4028
						pages_per_huge_page(h), false);
4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047 4048 4049

		/* fallback to copy_from_user outside mmap_sem */
		if (unlikely(ret)) {
			ret = -EFAULT;
			*pagep = page;
			/* don't free the page */
			goto out;
		}
	} else {
		page = *pagep;
		*pagep = NULL;
	}

	/*
	 * The memory barrier inside __SetPageUptodate makes sure that
	 * preceding stores to the page contents become visible before
	 * the set_pte_at() write.
	 */
	__SetPageUptodate(page);
	set_page_huge_active(page);

4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
		struct address_space *mapping = dst_vma->vm_file->f_mapping;
		pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);

		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4062 4063 4064 4065 4066 4067 4068
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4069 4070 4071 4072 4073 4074
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090

	_dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
	if (dst_vma->vm_flags & VM_WRITE)
		_dst_pte = huge_pte_mkdirty(_dst_pte);
	_dst_pte = pte_mkyoung(_dst_pte);

	set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);

	(void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
					dst_vma->vm_flags & VM_WRITE);
	hugetlb_count_add(pages_per_huge_page(h), dst_mm);

	/* No need to invalidate - it was non-present before */
	update_mmu_cache(dst_vma, dst_addr, dst_pte);

	spin_unlock(ptl);
4091 4092
	if (vm_shared)
		unlock_page(page);
4093 4094 4095 4096 4097
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4098 4099 4100
out_release_nounlock:
	if (vm_shared)
		unlock_page(page);
4101 4102 4103 4104
	put_page(page);
	goto out;
}

4105 4106 4107
long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
			 struct page **pages, struct vm_area_struct **vmas,
			 unsigned long *position, unsigned long *nr_pages,
4108
			 long i, unsigned int flags, int *nonblocking)
D
David Gibson 已提交
4109
{
4110 4111
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4112
	unsigned long remainder = *nr_pages;
4113
	struct hstate *h = hstate_vma(vma);
D
David Gibson 已提交
4114 4115

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4116
		pte_t *pte;
4117
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4118
		int absent;
A
Adam Litke 已提交
4119
		struct page *page;
D
David Gibson 已提交
4120

4121 4122 4123 4124 4125 4126 4127 4128 4129
		/*
		 * If we have a pending SIGKILL, don't keep faulting pages and
		 * potentially allocating memory.
		 */
		if (unlikely(fatal_signal_pending(current))) {
			remainder = 0;
			break;
		}

A
Adam Litke 已提交
4130 4131
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4132
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4133
		 * first, for the page indexing below to work.
4134 4135
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4136
		 */
4137
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
4138 4139
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4140 4141 4142 4143
		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
4144 4145 4146 4147
		 * 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
4148
		 */
H
Hugh Dickins 已提交
4149 4150
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4151 4152
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4153 4154 4155
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4156

4157 4158 4159 4160 4161 4162 4163 4164 4165 4166 4167
		/*
		 * We need call hugetlb_fault for both hugepages under migration
		 * (in which case hugetlb_fault waits for the migration,) and
		 * hwpoisoned hugepages (in which case we need to prevent the
		 * caller from accessing to them.) In order to do this, we use
		 * here is_swap_pte instead of is_hugetlb_entry_migration and
		 * is_hugetlb_entry_hwpoisoned. This is because it simply covers
		 * both cases, and because we can't follow correct pages
		 * directly from any kind of swap entries.
		 */
		if (absent || is_swap_pte(huge_ptep_get(pte)) ||
4168 4169
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
A
Adam Litke 已提交
4170
			int ret;
4171
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4172

4173 4174
			if (pte)
				spin_unlock(ptl);
4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187 4188
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
			if (nonblocking)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY;
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
				VM_WARN_ON_ONCE(fault_flags &
						FAULT_FLAG_ALLOW_RETRY);
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4189 4190 4191 4192 4193
				int err = vm_fault_to_errno(ret, flags);

				if (err)
					return err;

4194 4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
				if (nonblocking)
					*nonblocking = 0;
				*nr_pages = 0;
				/*
				 * VM_FAULT_RETRY must not return an
				 * error, it will return zero
				 * instead.
				 *
				 * No need to update "position" as the
				 * caller will not check it after
				 * *nr_pages is set to 0.
				 */
				return i;
			}
			continue;
A
Adam Litke 已提交
4213 4214
		}

4215
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4216
		page = pte_page(huge_ptep_get(pte));
4217
same_page:
4218
		if (pages) {
H
Hugh Dickins 已提交
4219
			pages[i] = mem_map_offset(page, pfn_offset);
4220
			get_page(pages[i]);
4221
		}
D
David Gibson 已提交
4222 4223 4224 4225 4226

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4227
		++pfn_offset;
D
David Gibson 已提交
4228 4229
		--remainder;
		++i;
4230
		if (vaddr < vma->vm_end && remainder &&
4231
				pfn_offset < pages_per_huge_page(h)) {
4232 4233 4234 4235 4236 4237
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4238
		spin_unlock(ptl);
D
David Gibson 已提交
4239
	}
4240
	*nr_pages = remainder;
4241 4242 4243 4244 4245
	/*
	 * setting position is actually required only if remainder is
	 * not zero but it's faster not to add a "if (remainder)"
	 * branch.
	 */
D
David Gibson 已提交
4246 4247
	*position = vaddr;

H
Hugh Dickins 已提交
4248
	return i ? i : -EFAULT;
D
David Gibson 已提交
4249
}
4250

4251 4252 4253 4254 4255 4256 4257 4258
#ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
/*
 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
 * implement this.
 */
#define flush_hugetlb_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
#endif

4259
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4260 4261 4262 4263 4264 4265
		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;
4266
	struct hstate *h = hstate_vma(vma);
4267
	unsigned long pages = 0;
4268 4269 4270 4271

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

4272
	mmu_notifier_invalidate_range_start(mm, start, end);
4273
	i_mmap_lock_write(vma->vm_file->f_mapping);
4274
	for (; address < end; address += huge_page_size(h)) {
4275
		spinlock_t *ptl;
4276 4277 4278
		ptep = huge_pte_offset(mm, address);
		if (!ptep)
			continue;
4279
		ptl = huge_pte_lock(h, mm, ptep);
4280 4281
		if (huge_pmd_unshare(mm, &address, ptep)) {
			pages++;
4282
			spin_unlock(ptl);
4283
			continue;
4284
		}
4285 4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302 4303 4304
		pte = huge_ptep_get(ptep);
		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
			spin_unlock(ptl);
			continue;
		}
		if (unlikely(is_hugetlb_entry_migration(pte))) {
			swp_entry_t entry = pte_to_swp_entry(pte);

			if (is_write_migration_entry(entry)) {
				pte_t newpte;

				make_migration_entry_read(&entry);
				newpte = swp_entry_to_pte(entry);
				set_huge_pte_at(mm, address, ptep, newpte);
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
4305
			pte = huge_ptep_get_and_clear(mm, address, ptep);
4306
			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
4307
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
4308
			set_huge_pte_at(mm, address, ptep, pte);
4309
			pages++;
4310
		}
4311
		spin_unlock(ptl);
4312
	}
4313
	/*
4314
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4315
	 * may have cleared our pud entry and done put_page on the page table:
4316
	 * once we release i_mmap_rwsem, another task can do the final put_page
4317 4318
	 * and that page table be reused and filled with junk.
	 */
4319
	flush_hugetlb_tlb_range(vma, start, end);
4320
	mmu_notifier_invalidate_range(mm, start, end);
4321
	i_mmap_unlock_write(vma->vm_file->f_mapping);
4322
	mmu_notifier_invalidate_range_end(mm, start, end);
4323 4324

	return pages << h->order;
4325 4326
}

4327 4328
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
4329
					struct vm_area_struct *vma,
4330
					vm_flags_t vm_flags)
4331
{
4332
	long ret, chg;
4333
	struct hstate *h = hstate_inode(inode);
4334
	struct hugepage_subpool *spool = subpool_inode(inode);
4335
	struct resv_map *resv_map;
4336
	long gbl_reserve;
4337

4338 4339 4340
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
4341
	 * without using reserves
4342
	 */
4343
	if (vm_flags & VM_NORESERVE)
4344 4345
		return 0;

4346 4347 4348 4349 4350 4351
	/*
	 * 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
	 */
4352
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
4353
		resv_map = inode_resv_map(inode);
4354

4355
		chg = region_chg(resv_map, from, to);
4356 4357 4358

	} else {
		resv_map = resv_map_alloc();
4359 4360 4361
		if (!resv_map)
			return -ENOMEM;

4362
		chg = to - from;
4363

4364 4365 4366 4367
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

4368 4369 4370 4371
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
4372

4373 4374 4375 4376 4377 4378 4379
	/*
	 * There must be enough pages in the subpool for the mapping. If
	 * the subpool has a minimum size, there may be some global
	 * reservations already in place (gbl_reserve).
	 */
	gbl_reserve = hugepage_subpool_get_pages(spool, chg);
	if (gbl_reserve < 0) {
4380 4381 4382
		ret = -ENOSPC;
		goto out_err;
	}
4383 4384

	/*
4385
	 * Check enough hugepages are available for the reservation.
4386
	 * Hand the pages back to the subpool if there are not
4387
	 */
4388
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
4389
	if (ret < 0) {
4390 4391
		/* put back original number of pages, chg */
		(void)hugepage_subpool_put_pages(spool, chg);
4392
		goto out_err;
K
Ken Chen 已提交
4393
	}
4394 4395 4396 4397 4398 4399 4400 4401 4402 4403 4404 4405

	/*
	 * 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
	 */
4406 4407 4408 4409 4410 4411 4412 4413 4414 4415 4416 4417 4418 4419 4420 4421 4422 4423
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
		long add = region_add(resv_map, from, to);

		if (unlikely(chg > add)) {
			/*
			 * pages in this range were added to the reserve
			 * map between region_chg and region_add.  This
			 * indicates a race with alloc_huge_page.  Adjust
			 * the subpool and reserve counts modified above
			 * based on the difference.
			 */
			long rsv_adjust;

			rsv_adjust = hugepage_subpool_put_pages(spool,
								chg - add);
			hugetlb_acct_memory(h, -rsv_adjust);
		}
	}
4424
	return 0;
4425
out_err:
4426
	if (!vma || vma->vm_flags & VM_MAYSHARE)
4427 4428 4429
		/* Don't call region_abort if region_chg failed */
		if (chg >= 0)
			region_abort(resv_map, from, to);
J
Joonsoo Kim 已提交
4430 4431
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
4432
	return ret;
4433 4434
}

4435 4436
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
4437
{
4438
	struct hstate *h = hstate_inode(inode);
4439
	struct resv_map *resv_map = inode_resv_map(inode);
4440
	long chg = 0;
4441
	struct hugepage_subpool *spool = subpool_inode(inode);
4442
	long gbl_reserve;
K
Ken Chen 已提交
4443

4444 4445 4446 4447 4448 4449 4450 4451 4452 4453 4454
	if (resv_map) {
		chg = region_del(resv_map, start, end);
		/*
		 * region_del() can fail in the rare case where a region
		 * must be split and another region descriptor can not be
		 * allocated.  If end == LONG_MAX, it will not fail.
		 */
		if (chg < 0)
			return chg;
	}

K
Ken Chen 已提交
4455
	spin_lock(&inode->i_lock);
4456
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
4457 4458
	spin_unlock(&inode->i_lock);

4459 4460 4461 4462 4463 4464
	/*
	 * If the subpool has a minimum size, the number of global
	 * reservations to be released may be adjusted.
	 */
	gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
	hugetlb_acct_memory(h, -gbl_reserve);
4465 4466

	return 0;
4467
}
4468

4469 4470 4471 4472 4473 4474 4475 4476 4477 4478 4479
#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
static unsigned long page_table_shareable(struct vm_area_struct *svma,
				struct vm_area_struct *vma,
				unsigned long addr, pgoff_t idx)
{
	unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
				svma->vm_start;
	unsigned long sbase = saddr & PUD_MASK;
	unsigned long s_end = sbase + PUD_SIZE;

	/* Allow segments to share if only one is marked locked */
E
Eric B Munson 已提交
4480 4481
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4482 4483 4484 4485 4486 4487 4488 4489 4490 4491 4492 4493 4494

	/*
	 * match the virtual addresses, permission and the alignment of the
	 * page table page.
	 */
	if (pmd_index(addr) != pmd_index(saddr) ||
	    vm_flags != svm_flags ||
	    sbase < svma->vm_start || svma->vm_end < s_end)
		return 0;

	return saddr;
}

4495
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4496 4497 4498 4499 4500 4501 4502 4503 4504
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
	if (vma->vm_flags & VM_MAYSHARE &&
	    vma->vm_start <= base && end <= vma->vm_end)
4505 4506
		return true;
	return false;
4507 4508 4509 4510 4511 4512 4513
}

/*
 * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
 * and returns the corresponding pte. While this is not necessary for the
 * !shared pmd case because we can allocate the pmd later as well, it makes the
 * code much cleaner. pmd allocation is essential for the shared case because
4514
 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4515 4516 4517 4518 4519 4520 4521 4522 4523 4524 4525 4526 4527
 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
 * bad pmd for sharing.
 */
pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
{
	struct vm_area_struct *vma = find_vma(mm, addr);
	struct address_space *mapping = vma->vm_file->f_mapping;
	pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
	struct vm_area_struct *svma;
	unsigned long saddr;
	pte_t *spte = NULL;
	pte_t *pte;
4528
	spinlock_t *ptl;
4529 4530 4531 4532

	if (!vma_shareable(vma, addr))
		return (pte_t *)pmd_alloc(mm, pud, addr);

4533
	i_mmap_lock_write(mapping);
4534 4535 4536 4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549 4550
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
			spte = huge_pte_offset(svma->vm_mm, saddr);
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

4551
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
4552
	if (pud_none(*pud)) {
4553 4554
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
4555
		mm_inc_nr_pmds(mm);
4556
	} else {
4557
		put_page(virt_to_page(spte));
4558
	}
4559
	spin_unlock(ptl);
4560 4561
out:
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
4562
	i_mmap_unlock_write(mapping);
4563 4564 4565 4566 4567 4568 4569 4570 4571 4572
	return pte;
}

/*
 * unmap huge page backed by shared pte.
 *
 * Hugetlb pte page is ref counted at the time of mapping.  If pte is shared
 * indicated by page_count > 1, unmap is achieved by clearing pud and
 * decrementing the ref count. If count == 1, the pte page is not shared.
 *
4573
 * called with page table lock held.
4574 4575 4576 4577 4578 4579 4580
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	pgd_t *pgd = pgd_offset(mm, *addr);
4581 4582
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
4583 4584 4585 4586 4587 4588 4589

	BUG_ON(page_count(virt_to_page(ptep)) == 0);
	if (page_count(virt_to_page(ptep)) == 1)
		return 0;

	pud_clear(pud);
	put_page(virt_to_page(ptep));
4590
	mm_dec_nr_pmds(mm);
4591 4592 4593
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
4594 4595 4596 4597 4598 4599
#define want_pmd_share()	(1)
#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
{
	return NULL;
}
4600 4601 4602 4603 4604

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}
4605
#define want_pmd_share()	(0)
4606 4607
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

4608 4609 4610 4611 4612
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
4613
	p4d_t *p4d;
4614 4615 4616 4617
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
4618 4619
	p4d = p4d_offset(pgd, addr);
	pud = pud_alloc(mm, p4d, addr);
4620 4621 4622 4623 4624 4625 4626 4627 4628 4629 4630
	if (pud) {
		if (sz == PUD_SIZE) {
			pte = (pte_t *)pud;
		} else {
			BUG_ON(sz != PMD_SIZE);
			if (want_pmd_share() && pud_none(*pud))
				pte = huge_pmd_share(mm, addr, pud);
			else
				pte = (pte_t *)pmd_alloc(mm, pud, addr);
		}
	}
4631
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4632 4633 4634 4635 4636 4637 4638

	return pte;
}

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;
4639
	p4d_t *p4d;
4640
	pud_t *pud;
4641
	pmd_t *pmd;
4642 4643

	pgd = pgd_offset(mm, addr);
4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
	pud = pud_offset(p4d, addr);
	if (!pud_present(*pud))
		return NULL;
	if (pud_huge(*pud))
		return (pte_t *)pud;
	pmd = pmd_offset(pud, addr);
4655 4656 4657
	return (pte_t *) pmd;
}

4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668 4669 4670 4671
#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */

/*
 * These functions are overwritable if your architecture needs its own
 * behavior.
 */
struct page * __weak
follow_huge_addr(struct mm_struct *mm, unsigned long address,
			      int write)
{
	return ERR_PTR(-EINVAL);
}

struct page * __weak
4672
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4673
		pmd_t *pmd, int flags)
4674
{
4675 4676
	struct page *page = NULL;
	spinlock_t *ptl;
4677
	pte_t pte;
4678 4679 4680 4681 4682 4683 4684 4685 4686
retry:
	ptl = pmd_lockptr(mm, pmd);
	spin_lock(ptl);
	/*
	 * make sure that the address range covered by this pmd is not
	 * unmapped from other threads.
	 */
	if (!pmd_huge(*pmd))
		goto out;
4687 4688
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
4689
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4690 4691 4692
		if (flags & FOLL_GET)
			get_page(page);
	} else {
4693
		if (is_hugetlb_entry_migration(pte)) {
4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704
			spin_unlock(ptl);
			__migration_entry_wait(mm, (pte_t *)pmd, ptl);
			goto retry;
		}
		/*
		 * hwpoisoned entry is treated as no_page_table in
		 * follow_page_mask().
		 */
	}
out:
	spin_unlock(ptl);
4705 4706 4707
	return page;
}

4708
struct page * __weak
4709
follow_huge_pud(struct mm_struct *mm, unsigned long address,
4710
		pud_t *pud, int flags)
4711
{
4712 4713
	if (flags & FOLL_GET)
		return NULL;
4714

4715
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4716 4717
}

4718 4719 4720 4721 4722 4723 4724 4725 4726
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
	if (flags & FOLL_GET)
		return NULL;

	return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
}

4727 4728
#ifdef CONFIG_MEMORY_FAILURE

4729 4730 4731
/*
 * This function is called from memory failure code.
 */
4732
int dequeue_hwpoisoned_huge_page(struct page *hpage)
4733 4734 4735
{
	struct hstate *h = page_hstate(hpage);
	int nid = page_to_nid(hpage);
4736
	int ret = -EBUSY;
4737 4738

	spin_lock(&hugetlb_lock);
4739 4740 4741 4742 4743
	/*
	 * Just checking !page_huge_active is not enough, because that could be
	 * an isolated/hwpoisoned hugepage (which have >0 refcount).
	 */
	if (!page_huge_active(hpage) && !page_count(hpage)) {
4744 4745 4746 4747 4748 4749 4750
		/*
		 * Hwpoisoned hugepage isn't linked to activelist or freelist,
		 * but dangling hpage->lru can trigger list-debug warnings
		 * (this happens when we call unpoison_memory() on it),
		 * so let it point to itself with list_del_init().
		 */
		list_del_init(&hpage->lru);
4751
		set_page_refcounted(hpage);
4752 4753 4754 4755
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		ret = 0;
	}
4756
	spin_unlock(&hugetlb_lock);
4757
	return ret;
4758
}
4759
#endif
4760 4761 4762

bool isolate_huge_page(struct page *page, struct list_head *list)
{
4763 4764
	bool ret = true;

4765
	VM_BUG_ON_PAGE(!PageHead(page), page);
4766
	spin_lock(&hugetlb_lock);
4767 4768 4769 4770 4771
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
4772
	list_move_tail(&page->lru, list);
4773
unlock:
4774
	spin_unlock(&hugetlb_lock);
4775
	return ret;
4776 4777 4778 4779
}

void putback_active_hugepage(struct page *page)
{
4780
	VM_BUG_ON_PAGE(!PageHead(page), page);
4781
	spin_lock(&hugetlb_lock);
4782
	set_page_huge_active(page);
4783 4784 4785 4786
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}